ide-tape.c 109.3 KB
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/*
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 * IDE ATAPI streaming tape driver.
 *
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 * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
 * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
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 *
 * This driver was constructed as a student project in the software laboratory
 * of the faculty of electrical engineering in the Technion - Israel's
 * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
 *
 * It is hereby placed under the terms of the GNU general public license.
 * (See linux/COPYING).
 *
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 * For a historical changelog see
 * Documentation/ide/ChangeLog.ide-tape.1995-2002
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 */

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#define IDETAPE_VERSION "1.20"
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#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
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#include <linux/jiffies.h>
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#include <linux/major.h>
#include <linux/errno.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/ide.h>
#include <linux/smp_lock.h>
#include <linux/completion.h>
#include <linux/bitops.h>
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#include <linux/mutex.h>
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#include <scsi/scsi.h>
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#include <asm/byteorder.h>
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#include <linux/irq.h>
#include <linux/uaccess.h>
#include <linux/io.h>
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#include <asm/unaligned.h>
#include <linux/mtio.h>

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enum {
	/* output errors only */
	DBG_ERR =		(1 << 0),
	/* output all sense key/asc */
	DBG_SENSE =		(1 << 1),
	/* info regarding all chrdev-related procedures */
	DBG_CHRDEV =		(1 << 2),
	/* all remaining procedures */
	DBG_PROCS =		(1 << 3),
	/* buffer alloc info (pc_stack & rq_stack) */
	DBG_PCRQ_STACK =	(1 << 4),
};

/* define to see debug info */
#define IDETAPE_DEBUG_LOG		0

#if IDETAPE_DEBUG_LOG
#define debug_log(lvl, fmt, args...)			\
{							\
	if (tape->debug_mask & lvl)			\
	printk(KERN_INFO "ide-tape: " fmt, ## args);	\
}
#else
#define debug_log(lvl, fmt, args...) do {} while (0)
#endif

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/**************************** Tunable parameters *****************************/


/*
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 * Pipelined mode parameters.
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 *
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 * We try to use the minimum number of stages which is enough to keep the tape
 * constantly streaming. To accomplish that, we implement a feedback loop around
 * the maximum number of stages:
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 *
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 * We start from MIN maximum stages (we will not even use MIN stages if we don't
 * need them), increment it by RATE*(MAX-MIN) whenever we sense that the
 * pipeline is empty, until we reach the optimum value or until we reach MAX.
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 *
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 * Setting the following parameter to 0 is illegal: the pipelined mode cannot be
 * disabled (idetape_calculate_speeds() divides by tape->max_stages.)
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 */
#define IDETAPE_MIN_PIPELINE_STAGES	  1
#define IDETAPE_MAX_PIPELINE_STAGES	400
#define IDETAPE_INCREASE_STAGES_RATE	 20

/*
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 * After each failed packet command we issue a request sense command and retry
 * the packet command IDETAPE_MAX_PC_RETRIES times.
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 *
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 * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
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 */
#define IDETAPE_MAX_PC_RETRIES		3

/*
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 * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
 * bytes. This is used for several packet commands (Not for READ/WRITE commands)
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 */
#define IDETAPE_PC_BUFFER_SIZE		256

/*
 *	In various places in the driver, we need to allocate storage
 *	for packet commands and requests, which will remain valid while
 *	we leave the driver to wait for an interrupt or a timeout event.
 */
#define IDETAPE_PC_STACK		(10 + IDETAPE_MAX_PC_RETRIES)

/*
 * Some drives (for example, Seagate STT3401A Travan) require a very long
 * timeout, because they don't return an interrupt or clear their busy bit
 * until after the command completes (even retension commands).
 */
#define IDETAPE_WAIT_CMD		(900*HZ)

/*
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 * The following parameter is used to select the point in the internal tape fifo
 * in which we will start to refill the buffer. Decreasing the following
 * parameter will improve the system's latency and interactive response, while
 * using a high value might improve system throughput.
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 */
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#define IDETAPE_FIFO_THRESHOLD		2
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/*
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 * DSC polling parameters.
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 *
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 * Polling for DSC (a single bit in the status register) is a very important
 * function in ide-tape. There are two cases in which we poll for DSC:
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 *
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 * 1. Before a read/write packet command, to ensure that we can transfer data
 * from/to the tape's data buffers, without causing an actual media access.
 * In case the tape is not ready yet, we take out our request from the device
 * request queue, so that ide.c could service requests from the other device
 * on the same interface in the meantime.
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 *
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 * 2. After the successful initialization of a "media access packet command",
 * which is a command that can take a long time to complete (the interval can
 * range from several seconds to even an hour). Again, we postpone our request
 * in the middle to free the bus for the other device. The polling frequency
 * here should be lower than the read/write frequency since those media access
 * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
 * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
 * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
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 *
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 * We also set a timeout for the timer, in case something goes wrong. The
 * timeout should be longer then the maximum execution time of a tape operation.
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 */
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/* DSC timings. */
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#define IDETAPE_DSC_RW_MIN		5*HZ/100	/* 50 msec */
#define IDETAPE_DSC_RW_MAX		40*HZ/100	/* 400 msec */
#define IDETAPE_DSC_RW_TIMEOUT		2*60*HZ		/* 2 minutes */
#define IDETAPE_DSC_MA_FAST		2*HZ		/* 2 seconds */
#define IDETAPE_DSC_MA_THRESHOLD	5*60*HZ		/* 5 minutes */
#define IDETAPE_DSC_MA_SLOW		30*HZ		/* 30 seconds */
#define IDETAPE_DSC_MA_TIMEOUT		2*60*60*HZ	/* 2 hours */

/*************************** End of tunable parameters ***********************/

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/* Read/Write error simulation */
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#define SIMULATE_ERRORS			0

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/* tape directions */
enum {
	IDETAPE_DIR_NONE  = (1 << 0),
	IDETAPE_DIR_READ  = (1 << 1),
	IDETAPE_DIR_WRITE = (1 << 2),
};
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struct idetape_bh {
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	u32 b_size;
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	atomic_t b_count;
	struct idetape_bh *b_reqnext;
	char *b_data;
};

typedef struct idetape_packet_command_s {
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	/* Actual packet bytes */
	u8 c[12];
	/* On each retry, we increment retries */
	int retries;
	/* Error code */
	int error;
	/* Bytes to transfer */
	int request_transfer;
	/* Bytes actually transferred */
	int actually_transferred;
	/* Size of our data buffer */
	int buffer_size;
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	struct idetape_bh *bh;
	char *b_data;
	int b_count;
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	/* Data buffer */
	u8 *buffer;
	/* Pointer into the above buffer */
	u8 *current_position;
	/* Called when this packet command is completed */
	ide_startstop_t (*callback) (ide_drive_t *);
	/* Temporary buffer */
	u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE];
	/* Status/Action bit flags: long for set_bit */
	unsigned long flags;
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} idetape_pc_t;

/*
 *	Packet command flag bits.
 */
/* Set when an error is considered normal - We won't retry */
#define	PC_ABORT			0
/* 1 When polling for DSC on a media access command */
#define PC_WAIT_FOR_DSC			1
/* 1 when we prefer to use DMA if possible */
#define PC_DMA_RECOMMENDED		2
/* 1 while DMA in progress */
#define	PC_DMA_IN_PROGRESS		3
/* 1 when encountered problem during DMA */
#define	PC_DMA_ERROR			4
/* Data direction */
#define	PC_WRITING			5

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/* A pipeline stage. */
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typedef struct idetape_stage_s {
	struct request rq;			/* The corresponding request */
	struct idetape_bh *bh;			/* The data buffers */
	struct idetape_stage_s *next;		/* Pointer to the next stage */
} idetape_stage_t;

/*
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 * Most of our global data which we need to save even as we leave the driver due
 * to an interrupt or a timer event is stored in the struct defined below.
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 */
typedef struct ide_tape_obj {
	ide_drive_t	*drive;
	ide_driver_t	*driver;
	struct gendisk	*disk;
	struct kref	kref;

	/*
	 *	Since a typical character device operation requires more
	 *	than one packet command, we provide here enough memory
	 *	for the maximum of interconnected packet commands.
	 *	The packet commands are stored in the circular array pc_stack.
	 *	pc_stack_index points to the last used entry, and warps around
	 *	to the start when we get to the last array entry.
	 *
	 *	pc points to the current processed packet command.
	 *
	 *	failed_pc points to the last failed packet command, or contains
	 *	NULL if we do not need to retry any packet command. This is
	 *	required since an additional packet command is needed before the
	 *	retry, to get detailed information on what went wrong.
	 */
	/* Current packet command */
	idetape_pc_t *pc;
	/* Last failed packet command */
	idetape_pc_t *failed_pc;
	/* Packet command stack */
	idetape_pc_t pc_stack[IDETAPE_PC_STACK];
	/* Next free packet command storage space */
	int pc_stack_index;
	struct request rq_stack[IDETAPE_PC_STACK];
	/* We implement a circular array */
	int rq_stack_index;

	/*
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	 * DSC polling variables.
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	 *
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	 * While polling for DSC we use postponed_rq to postpone the current
	 * request so that ide.c will be able to service pending requests on the
	 * other device. Note that at most we will have only one DSC (usually
	 * data transfer) request in the device request queue. Additional
	 * requests can be queued in our internal pipeline, but they will be
	 * visible to ide.c only one at a time.
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	 */
	struct request *postponed_rq;
	/* The time in which we started polling for DSC */
	unsigned long dsc_polling_start;
	/* Timer used to poll for dsc */
	struct timer_list dsc_timer;
	/* Read/Write dsc polling frequency */
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	unsigned long best_dsc_rw_freq;
	unsigned long dsc_poll_freq;
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	unsigned long dsc_timeout;

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	/* Read position information */
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	u8 partition;
	/* Current block */
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	unsigned int first_frame;
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	/* Last error information */
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	u8 sense_key, asc, ascq;

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	/* Character device operation */
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	unsigned int minor;
	/* device name */
	char name[4];
	/* Current character device data transfer direction */
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	u8 chrdev_dir;
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	/* tape block size, usually 512 or 1024 bytes */
	unsigned short blk_size;
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	int user_bs_factor;
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	/* Copy of the tape's Capabilities and Mechanical Page */
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	u8 caps[20];
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	/*
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	 * Active data transfer request parameters.
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	 *
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	 * At most, there is only one ide-tape originated data transfer request
	 * in the device request queue. This allows ide.c to easily service
	 * requests from the other device when we postpone our active request.
	 * In the pipelined operation mode, we use our internal pipeline
	 * structure to hold more data requests. The data buffer size is chosen
	 * based on the tape's recommendation.
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	 */
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	/* ptr to the request which is waiting in the device request queue */
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	struct request *active_data_rq;
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	/* Data buffer size chosen based on the tape's recommendation */
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	int stage_size;
	idetape_stage_t *merge_stage;
	int merge_stage_size;
	struct idetape_bh *bh;
	char *b_data;
	int b_count;
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	/*
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	 * Pipeline parameters.
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	 *
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	 * To accomplish non-pipelined mode, we simply set the following
	 * variables to zero (or NULL, where appropriate).
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	 */
	/* Number of currently used stages */
	int nr_stages;
	/* Number of pending stages */
	int nr_pending_stages;
	/* We will not allocate more than this number of stages */
	int max_stages, min_pipeline, max_pipeline;
	/* The first stage which will be removed from the pipeline */
	idetape_stage_t *first_stage;
	/* The currently active stage */
	idetape_stage_t *active_stage;
	/* Will be serviced after the currently active request */
	idetape_stage_t *next_stage;
	/* New requests will be added to the pipeline here */
	idetape_stage_t *last_stage;
	/* Optional free stage which we can use */
	idetape_stage_t *cache_stage;
	int pages_per_stage;
	/* Wasted space in each stage */
	int excess_bh_size;

	/* Status/Action flags: long for set_bit */
	unsigned long flags;
	/* protects the ide-tape queue */
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	spinlock_t lock;
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	/* Measures average tape speed */
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	unsigned long avg_time;
	int avg_size;
	int avg_speed;

	/* the door is currently locked */
	int door_locked;
	/* the tape hardware is write protected */
	char drv_write_prot;
	/* the tape is write protected (hardware or opened as read-only) */
	char write_prot;

	/*
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	 * Limit the number of times a request can be postponed, to avoid an
	 * infinite postpone deadlock.
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	 */
	int postpone_cnt;

	/*
	 * Measures number of frames:
	 *
	 * 1. written/read to/from the driver pipeline (pipeline_head).
	 * 2. written/read to/from the tape buffers (idetape_bh).
	 * 3. written/read by the tape to/from the media (tape_head).
	 */
	int pipeline_head;
	int buffer_head;
	int tape_head;
	int last_tape_head;

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	/* Speed control at the tape buffers input/output */
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	unsigned long insert_time;
	int insert_size;
	int insert_speed;
	int max_insert_speed;
	int measure_insert_time;

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	/* Speed regulation negative feedback loop */
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	int speed_control;
	int pipeline_head_speed;
	int controlled_pipeline_head_speed;
	int uncontrolled_pipeline_head_speed;
	int controlled_last_pipeline_head;
	unsigned long uncontrolled_pipeline_head_time;
	unsigned long controlled_pipeline_head_time;
	int controlled_previous_pipeline_head;
	int uncontrolled_previous_pipeline_head;
	unsigned long controlled_previous_head_time;
	unsigned long uncontrolled_previous_head_time;
	int restart_speed_control_req;

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	u32 debug_mask;
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} idetape_tape_t;

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static DEFINE_MUTEX(idetape_ref_mutex);
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static struct class *idetape_sysfs_class;

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#define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)

#define ide_tape_g(disk) \
	container_of((disk)->private_data, struct ide_tape_obj, driver)

static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
{
	struct ide_tape_obj *tape = NULL;

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	mutex_lock(&idetape_ref_mutex);
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	tape = ide_tape_g(disk);
	if (tape)
		kref_get(&tape->kref);
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	mutex_unlock(&idetape_ref_mutex);
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	return tape;
}

static void ide_tape_release(struct kref *);

static void ide_tape_put(struct ide_tape_obj *tape)
{
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	mutex_lock(&idetape_ref_mutex);
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	kref_put(&tape->kref, ide_tape_release);
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	mutex_unlock(&idetape_ref_mutex);
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}

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/* Tape door status */
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#define DOOR_UNLOCKED			0
#define DOOR_LOCKED			1
#define DOOR_EXPLICITLY_LOCKED		2

/*
 *	Tape flag bits values.
 */
#define IDETAPE_IGNORE_DSC		0
#define IDETAPE_ADDRESS_VALID		1	/* 0 When the tape position is unknown */
#define IDETAPE_BUSY			2	/* Device already opened */
#define IDETAPE_PIPELINE_ERROR		3	/* Error detected in a pipeline stage */
#define IDETAPE_DETECT_BS		4	/* Attempt to auto-detect the current user block size */
#define IDETAPE_FILEMARK		5	/* Currently on a filemark */
#define IDETAPE_DRQ_INTERRUPT		6	/* DRQ interrupt device */
#define IDETAPE_READ_ERROR		7
#define IDETAPE_PIPELINE_ACTIVE		8	/* pipeline active */
/* 0 = no tape is loaded, so we don't rewind after ejecting */
#define IDETAPE_MEDIUM_PRESENT		9

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/* Some defines for the SPACE command */
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#define IDETAPE_SPACE_OVER_FILEMARK	1
#define IDETAPE_SPACE_TO_EOD		3

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/* Some defines for the LOAD UNLOAD command */
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#define IDETAPE_LU_LOAD_MASK		1
#define IDETAPE_LU_RETENSION_MASK	2
#define IDETAPE_LU_EOT_MASK		4

/*
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 * Special requests for our block device strategy routine.
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 *
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 * In order to service a character device command, we add special requests to
 * the tail of our block device request queue and wait for their completion.
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 */

enum {
	REQ_IDETAPE_PC1		= (1 << 0), /* packet command (first stage) */
	REQ_IDETAPE_PC2		= (1 << 1), /* packet command (second stage) */
	REQ_IDETAPE_READ	= (1 << 2),
	REQ_IDETAPE_WRITE	= (1 << 3),
};

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/* Error codes returned in rq->errors to the higher part of the driver. */
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#define	IDETAPE_ERROR_GENERAL		101
#define	IDETAPE_ERROR_FILEMARK		102
#define	IDETAPE_ERROR_EOD		103

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/* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
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#define IDETAPE_BLOCK_DESCRIPTOR	0
#define	IDETAPE_CAPABILITIES_PAGE	0x2a

/*
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 * The variables below are used for the character device interface. Additional
 * state variables are defined in our ide_drive_t structure.
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 */
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static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
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#define ide_tape_f(file) ((file)->private_data)

static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
{
	struct ide_tape_obj *tape = NULL;

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	mutex_lock(&idetape_ref_mutex);
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	tape = idetape_devs[i];
	if (tape)
		kref_get(&tape->kref);
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	mutex_unlock(&idetape_ref_mutex);
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	return tape;
}

/*
 * Too bad. The drive wants to send us data which we are not ready to accept.
 * Just throw it away.
 */
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static void idetape_discard_data(ide_drive_t *drive, unsigned int bcount)
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{
	while (bcount--)
		(void) HWIF(drive)->INB(IDE_DATA_REG);
}

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static void idetape_input_buffers(ide_drive_t *drive, idetape_pc_t *pc,
				  unsigned int bcount)
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{
	struct idetape_bh *bh = pc->bh;
	int count;

	while (bcount) {
		if (bh == NULL) {
			printk(KERN_ERR "ide-tape: bh == NULL in "
				"idetape_input_buffers\n");
			idetape_discard_data(drive, bcount);
			return;
		}
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		count = min(
			(unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
			bcount);
		HWIF(drive)->atapi_input_bytes(drive, bh->b_data +
					atomic_read(&bh->b_count), count);
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		bcount -= count;
		atomic_add(count, &bh->b_count);
		if (atomic_read(&bh->b_count) == bh->b_size) {
			bh = bh->b_reqnext;
			if (bh)
				atomic_set(&bh->b_count, 0);
		}
	}
	pc->bh = bh;
}

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static void idetape_output_buffers(ide_drive_t *drive, idetape_pc_t *pc,
				   unsigned int bcount)
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{
	struct idetape_bh *bh = pc->bh;
	int count;

	while (bcount) {
		if (bh == NULL) {
568 569
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
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			return;
		}
		count = min((unsigned int)pc->b_count, (unsigned int)bcount);
		HWIF(drive)->atapi_output_bytes(drive, pc->b_data, count);
		bcount -= count;
		pc->b_data += count;
		pc->b_count -= count;
		if (!pc->b_count) {
578 579
			bh = bh->b_reqnext;
			pc->bh = bh;
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			if (bh) {
				pc->b_data = bh->b_data;
				pc->b_count = atomic_read(&bh->b_count);
			}
		}
	}
}

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static void idetape_update_buffers(idetape_pc_t *pc)
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{
	struct idetape_bh *bh = pc->bh;
	int count;
	unsigned int bcount = pc->actually_transferred;

	if (test_bit(PC_WRITING, &pc->flags))
		return;
	while (bcount) {
		if (bh == NULL) {
598 599
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
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			return;
		}
		count = min((unsigned int)bh->b_size, (unsigned int)bcount);
		atomic_set(&bh->b_count, count);
		if (atomic_read(&bh->b_count) == bh->b_size)
			bh = bh->b_reqnext;
		bcount -= count;
	}
	pc->bh = bh;
}

/*
 *	idetape_next_pc_storage returns a pointer to a place in which we can
 *	safely store a packet command, even though we intend to leave the
 *	driver. A storage space for a maximum of IDETAPE_PC_STACK packet
 *	commands is allocated at initialization time.
 */
617
static idetape_pc_t *idetape_next_pc_storage(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;

621 622
	debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);

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	if (tape->pc_stack_index == IDETAPE_PC_STACK)
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		tape->pc_stack_index = 0;
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	return (&tape->pc_stack[tape->pc_stack_index++]);
}

/*
 *	idetape_next_rq_storage is used along with idetape_next_pc_storage.
 *	Since we queue packet commands in the request queue, we need to
 *	allocate a request, along with the allocation of a packet command.
 */
633

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/**************************************************************
 *                                                            *
 *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
 *  followed later on by kfree().   -ml                       *
 *                                                            *
 **************************************************************/
640 641

static struct request *idetape_next_rq_storage(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;

645 646
	debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);

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	if (tape->rq_stack_index == IDETAPE_PC_STACK)
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		tape->rq_stack_index = 0;
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	return (&tape->rq_stack[tape->rq_stack_index++]);
}

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static void idetape_init_pc(idetape_pc_t *pc)
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{
	memset(pc->c, 0, 12);
	pc->retries = 0;
	pc->flags = 0;
	pc->request_transfer = 0;
	pc->buffer = pc->pc_buffer;
	pc->buffer_size = IDETAPE_PC_BUFFER_SIZE;
	pc->bh = NULL;
	pc->b_data = NULL;
}

/*
665 666
 * called on each failed packet command retry to analyze the request sense. We
 * currently do not utilize this information.
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 */
668
static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
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{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t *pc = tape->failed_pc;

673 674 675
	tape->sense_key = sense[2] & 0xF;
	tape->asc       = sense[12];
	tape->ascq      = sense[13];
676 677 678

	debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
		 pc->c[0], tape->sense_key, tape->asc, tape->ascq);
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	/* Correct pc->actually_transferred by asking the tape.	 */
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	if (test_bit(PC_DMA_ERROR, &pc->flags)) {
682
		pc->actually_transferred = pc->request_transfer -
683
			tape->blk_size *
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			be32_to_cpu(get_unaligned((u32 *)&sense[3]));
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		idetape_update_buffers(pc);
	}

	/*
	 * If error was the result of a zero-length read or write command,
	 * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
	 * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
	 */
693
	if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
694 695 696
	    /* length == 0 */
	    && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
		if (tape->sense_key == 5) {
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			/* don't report an error, everything's ok */
			pc->error = 0;
			/* don't retry read/write */
			set_bit(PC_ABORT, &pc->flags);
		}
	}
703
	if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
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		pc->error = IDETAPE_ERROR_FILEMARK;
		set_bit(PC_ABORT, &pc->flags);
	}
707
	if (pc->c[0] == WRITE_6) {
708 709
		if ((sense[2] & 0x40) || (tape->sense_key == 0xd
		     && tape->asc == 0x0 && tape->ascq == 0x2)) {
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			pc->error = IDETAPE_ERROR_EOD;
			set_bit(PC_ABORT, &pc->flags);
		}
	}
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	if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
715
		if (tape->sense_key == 8) {
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			pc->error = IDETAPE_ERROR_EOD;
			set_bit(PC_ABORT, &pc->flags);
		}
		if (!test_bit(PC_ABORT, &pc->flags) &&
		    pc->actually_transferred)
			pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
	}
}

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static void idetape_activate_next_stage(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *stage = tape->next_stage;
	struct request *rq = &stage->rq;

731 732
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

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	if (stage == NULL) {
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		printk(KERN_ERR "ide-tape: bug: Trying to activate a non"
				" existing stage\n");
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		return;
	}

	rq->rq_disk = tape->disk;
	rq->buffer = NULL;
	rq->special = (void *)stage->bh;
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	tape->active_data_rq = rq;
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	tape->active_stage = stage;
	tape->next_stage = stage->next;
}

747
/* Free a stage along with its related buffers completely. */
748
static void __idetape_kfree_stage(idetape_stage_t *stage)
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{
	struct idetape_bh *prev_bh, *bh = stage->bh;
	int size;

	while (bh != NULL) {
		if (bh->b_data != NULL) {
			size = (int) bh->b_size;
			while (size > 0) {
				free_page((unsigned long) bh->b_data);
				size -= PAGE_SIZE;
				bh->b_data += PAGE_SIZE;
			}
		}
		prev_bh = bh;
		bh = bh->b_reqnext;
		kfree(prev_bh);
	}
	kfree(stage);
}

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static void idetape_kfree_stage(idetape_tape_t *tape, idetape_stage_t *stage)
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{
	__idetape_kfree_stage(stage);
}

/*
775 776
 * Remove tape->first_stage from the pipeline. The caller should avoid race
 * conditions.
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 */
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static void idetape_remove_stage_head(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *stage;
782 783 784

	debug_log(DBG_PROCS, "Enter %s\n", __func__);

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	if (tape->first_stage == NULL) {
		printk(KERN_ERR "ide-tape: bug: tape->first_stage is NULL\n");
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		return;
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	}
	if (tape->active_stage == tape->first_stage) {
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		printk(KERN_ERR "ide-tape: bug: Trying to free our active "
				"pipeline stage\n");
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		return;
	}
	stage = tape->first_stage;
	tape->first_stage = stage->next;
	idetape_kfree_stage(tape, stage);
	tape->nr_stages--;
	if (tape->first_stage == NULL) {
		tape->last_stage = NULL;
		if (tape->next_stage != NULL)
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			printk(KERN_ERR "ide-tape: bug: tape->next_stage !="
					" NULL\n");
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		if (tape->nr_stages)
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			printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 "
					"now\n");
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	}
}

/*
 * This will free all the pipeline stages starting from new_last_stage->next
 * to the end of the list, and point tape->last_stage to new_last_stage.
 */
static void idetape_abort_pipeline(ide_drive_t *drive,
				   idetape_stage_t *new_last_stage)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *stage = new_last_stage->next;
	idetape_stage_t *nstage;

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	debug_log(DBG_PROCS, "%s: Enter %s\n", tape->name, __func__);

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	while (stage) {
		nstage = stage->next;
		idetape_kfree_stage(tape, stage);
		--tape->nr_stages;
		--tape->nr_pending_stages;
		stage = nstage;
	}
	if (new_last_stage)
		new_last_stage->next = NULL;
	tape->last_stage = new_last_stage;
	tape->next_stage = NULL;
}

/*
836 837
 * Finish servicing a request and insert a pending pipeline request into the
 * main device queue.
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 */
static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
{
	struct request *rq = HWGROUP(drive)->rq;
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;
	int error;
	int remove_stage = 0;
	idetape_stage_t *active_stage;

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	debug_log(DBG_PROCS, "Enter %s\n", __func__);
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	switch (uptodate) {
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	case 0:	error = IDETAPE_ERROR_GENERAL; break;
	case 1: error = 0; break;
	default: error = uptodate;
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	}
	rq->errors = error;
	if (error)
		tape->failed_pc = NULL;

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	if (!blk_special_request(rq)) {
		ide_end_request(drive, uptodate, nr_sects);
		return 0;
	}

864
	spin_lock_irqsave(&tape->lock, flags);
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	/* The request was a pipelined data transfer request */
867
	if (tape->active_data_rq == rq) {
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		active_stage = tape->active_stage;
		tape->active_stage = NULL;
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		tape->active_data_rq = NULL;
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		tape->nr_pending_stages--;
		if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
			remove_stage = 1;
			if (error) {
				set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
				if (error == IDETAPE_ERROR_EOD)
877 878
					idetape_abort_pipeline(drive,
								active_stage);
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			}
		} else if (rq->cmd[0] & REQ_IDETAPE_READ) {
			if (error == IDETAPE_ERROR_EOD) {
				set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
				idetape_abort_pipeline(drive, active_stage);
			}
		}
		if (tape->next_stage != NULL) {
887
			idetape_activate_next_stage(drive);
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889
			/* Insert the next request into the request queue. */
890 891
			(void)ide_do_drive_cmd(drive, tape->active_data_rq,
						ide_end);
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		} else if (!error) {
893 894 895 896 897 898 899 900 901 902 903 904 905 906 907
			/*
			 * This is a part of the feedback loop which tries to
			 * find the optimum number of stages. We are starting
			 * from a minimum maximum number of stages, and if we
			 * sense that the pipeline is empty, we try to increase
			 * it, until we reach the user compile time memory
			 * limit.
			 */
			int i = (tape->max_pipeline - tape->min_pipeline) / 10;

			tape->max_stages += max(i, 1);
			tape->max_stages = max(tape->max_stages,
						tape->min_pipeline);
			tape->max_stages = min(tape->max_stages,
						tape->max_pipeline);
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		}
	}
	ide_end_drive_cmd(drive, 0, 0);

	if (remove_stage)
		idetape_remove_stage_head(drive);
914
	if (tape->active_data_rq == NULL)
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		clear_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
916
	spin_unlock_irqrestore(&tape->lock, flags);
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	return 0;
}

920
static ide_startstop_t idetape_request_sense_callback(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;

924 925
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

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	if (!tape->pc->error) {
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		idetape_analyze_error(drive, tape->pc->buffer);
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		idetape_end_request(drive, 1, 0);
	} else {
930 931
		printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - "
				"Aborting request!\n");
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		idetape_end_request(drive, 0, 0);
	}
	return ide_stopped;
}

937
static void idetape_create_request_sense_cmd(idetape_pc_t *pc)
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{
939
	idetape_init_pc(pc);
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	pc->c[0] = REQUEST_SENSE;
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	pc->c[4] = 20;
	pc->request_transfer = 20;
	pc->callback = &idetape_request_sense_callback;
}

static void idetape_init_rq(struct request *rq, u8 cmd)
{
	memset(rq, 0, sizeof(*rq));
949
	rq->cmd_type = REQ_TYPE_SPECIAL;
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	rq->cmd[0] = cmd;
}

/*
954 955 956 957 958
 * Generate a new packet command request in front of the request queue, before
 * the current request, so that it will be processed immediately, on the next
 * pass through the driver. The function below is called from the request
 * handling part of the driver (the "bottom" part). Safe storage for the request
 * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
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 *
960 961 962
 * Memory for those requests is pre-allocated at initialization time, and is
 * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
 * the maximum possible number of inter-dependent packet commands.
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 *
964 965 966
 * The higher level of the driver - The ioctl handler and the character device
 * handling functions should queue request to the lower level part and wait for
 * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
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 */
968 969
static void idetape_queue_pc_head(ide_drive_t *drive, idetape_pc_t *pc,
				  struct request *rq)
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{
	struct ide_tape_obj *tape = drive->driver_data;

	idetape_init_rq(rq, REQ_IDETAPE_PC1);
	rq->buffer = (char *) pc;
	rq->rq_disk = tape->disk;
	(void) ide_do_drive_cmd(drive, rq, ide_preempt);
}

/*
 *	idetape_retry_pc is called when an error was detected during the
 *	last packet command. We queue a request sense packet command in
 *	the head of the request list.
 */
static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t *pc;
	struct request *rq;

990
	(void)ide_read_error(drive);
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	pc = idetape_next_pc_storage(drive);
	rq = idetape_next_rq_storage(drive);
	idetape_create_request_sense_cmd(pc);
	set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
	idetape_queue_pc_head(drive, pc, rq);
	return ide_stopped;
}

/*
1000 1001
 * Postpone the current request so that ide.c will be able to service requests
 * from another device on the same hwgroup while we are polling for DSC.
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 */
1003
static void idetape_postpone_request(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;

1007 1008
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

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	tape->postponed_rq = HWGROUP(drive)->rq;
1010
	ide_stall_queue(drive, tape->dsc_poll_freq);
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}

1013 1014
typedef void idetape_io_buf(ide_drive_t *, idetape_pc_t *, unsigned int);

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/*
1016 1017 1018 1019
 * This is the usual interrupt handler which will be called during a packet
 * command. We will transfer some of the data (as requested by the drive) and
 * will re-point interrupt handler to us. When data transfer is finished, we
 * will act according to the algorithm described before
1020
 * idetape_issue_pc.
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 */
1022
static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
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{
	ide_hwif_t *hwif = drive->hwif;
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t *pc = tape->pc;
1027 1028
	xfer_func_t *xferfunc;
	idetape_io_buf *iobuf;
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	unsigned int temp;
#if SIMULATE_ERRORS
1031
	static int error_sim_count;
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#endif
1033
	u16 bcount;
1034
	u8 stat, ireason;
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	debug_log(DBG_PROCS, "Enter %s - interrupt handler\n", __func__);
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	/* Clear the interrupt */
1039
	stat = ide_read_status(drive);
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	if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1042
		if (hwif->ide_dma_end(drive) || (stat & ERR_STAT)) {
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			/*
			 * A DMA error is sometimes expected. For example,
			 * if the tape is crossing a filemark during a
			 * READ command, it will issue an irq and position
			 * itself before the filemark, so that only a partial
			 * data transfer will occur (which causes the DMA
			 * error). In that case, we will later ask the tape
			 * how much bytes of the original request were
			 * actually transferred (we can't receive that
			 * information from the DMA engine on most chipsets).
			 */

			/*
			 * On the contrary, a DMA error is never expected;
			 * it usually indicates a hardware error or abort.
			 * If the tape crosses a filemark during a READ
			 * command, it will issue an irq and position itself
			 * after the filemark (not before). Only a partial
			 * data transfer will occur, but no DMA error.
			 * (AS, 19 Apr 2001)
			 */
			set_bit(PC_DMA_ERROR, &pc->flags);
		} else {
			pc->actually_transferred = pc->request_transfer;
			idetape_update_buffers(pc);
		}
1069 1070
		debug_log(DBG_PROCS, "DMA finished\n");

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	}

	/* No more interrupts */
1074
	if ((stat & DRQ_STAT) == 0) {
1075 1076
		debug_log(DBG_SENSE, "Packet command completed, %d bytes"
				" transferred\n", pc->actually_transferred);
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1078
		clear_bit(PC_DMA_IN_PROGRESS, &pc->flags);
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		local_irq_enable();

#if SIMULATE_ERRORS
1082
		if ((pc->c[0] == WRITE_6 || pc->c[0] == READ_6) &&
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		    (++error_sim_count % 100) == 0) {
			printk(KERN_INFO "ide-tape: %s: simulating error\n",
				tape->name);
1086
			stat |= ERR_STAT;
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		}
#endif
1089
		if ((stat & ERR_STAT) && pc->c[0] == REQUEST_SENSE)
1090 1091 1092
			stat &= ~ERR_STAT;
		if ((stat & ERR_STAT) || test_bit(PC_DMA_ERROR, &pc->flags)) {
			/* Error detected */
1093 1094
			debug_log(DBG_ERR, "%s: I/O error\n", tape->name);

1095
			if (pc->c[0] == REQUEST_SENSE) {
1096 1097
				printk(KERN_ERR "ide-tape: I/O error in request"
						" sense command\n");
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				return ide_do_reset(drive);
			}
1100 1101 1102
			debug_log(DBG_ERR, "[cmd %x]: check condition\n",
					pc->c[0]);

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			/* Retry operation */
			return idetape_retry_pc(drive);
		}
		pc->error = 0;
		if (test_bit(PC_WAIT_FOR_DSC, &pc->flags) &&
1108
		    (stat & SEEK_STAT) == 0) {
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			/* Media access command */
			tape->dsc_polling_start = jiffies;
1111
			tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
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			tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
			/* Allow ide.c to handle other requests */
			idetape_postpone_request(drive);
			return ide_stopped;
		}
		if (tape->failed_pc == pc)
			tape->failed_pc = NULL;
		/* Command finished - Call the callback function */
		return pc->callback(drive);
	}
	if (test_and_clear_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
		printk(KERN_ERR "ide-tape: The tape wants to issue more "
				"interrupts in DMA mode\n");
		printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
1126
		ide_dma_off(drive);
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		return ide_do_reset(drive);
	}
	/* Get the number of bytes to transfer on this interrupt. */
1130 1131
	bcount = (hwif->INB(IDE_BCOUNTH_REG) << 8) |
		  hwif->INB(IDE_BCOUNTL_REG);
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1133
	ireason = hwif->INB(IDE_IREASON_REG);
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1135
	if (ireason & CD) {
1136
		printk(KERN_ERR "ide-tape: CoD != 0 in %s\n", __func__);
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		return ide_do_reset(drive);
	}
1139
	if (((ireason & IO) == IO) == test_bit(PC_WRITING, &pc->flags)) {
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		/* Hopefully, we will never get here */
		printk(KERN_ERR "ide-tape: We wanted to %s, ",
1142
				(ireason & IO) ? "Write" : "Read");
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		printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
1144
				(ireason & IO) ? "Read" : "Write");
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		return ide_do_reset(drive);
	}
	if (!test_bit(PC_WRITING, &pc->flags)) {
		/* Reading - Check that we have enough space */
1149
		temp = pc->actually_transferred + bcount;
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		if (temp > pc->request_transfer) {
			if (temp > pc->buffer_size) {
1152 1153 1154
				printk(KERN_ERR "ide-tape: The tape wants to "
					"send us more data than expected "
					"- discarding data\n");
1155
				idetape_discard_data(drive, bcount);
1156 1157
				ide_set_handler(drive, &idetape_pc_intr,
						IDETAPE_WAIT_CMD, NULL);
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				return ide_started;
			}
1160 1161
			debug_log(DBG_SENSE, "The tape wants to send us more "
				"data than expected - allowing transfer\n");
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		}
1163 1164
		iobuf = &idetape_input_buffers;
		xferfunc = hwif->atapi_input_bytes;
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	} else {
1166 1167
		iobuf = &idetape_output_buffers;
		xferfunc = hwif->atapi_output_bytes;
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	}
1169 1170 1171 1172 1173 1174

	if (pc->bh)
		iobuf(drive, pc, bcount);
	else
		xferfunc(drive, pc->current_position, bcount);

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	/* Update the current position */
1176 1177
	pc->actually_transferred += bcount;
	pc->current_position += bcount;
1178 1179 1180 1181

	debug_log(DBG_SENSE, "[cmd %x] transferred %d bytes on that intr.\n",
			pc->c[0], bcount);

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	/* And set the interrupt handler again */
	ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
	return ide_started;
}

/*
1188
 * Packet Command Interface
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 *
1190 1191 1192
 * The current Packet Command is available in tape->pc, and will not change
 * until we finish handling it. Each packet command is associated with a
 * callback function that will be called when the command is finished.
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 *
1194
 * The handling will be done in three stages:
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 *
1196 1197
 * 1. idetape_issue_pc will send the packet command to the drive, and will set
 * the interrupt handler to idetape_pc_intr.
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 *
1199 1200
 * 2. On each interrupt, idetape_pc_intr will be called. This step will be
 * repeated until the device signals us that no more interrupts will be issued.
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 *
1202 1203 1204 1205 1206 1207 1208
 * 3. ATAPI Tape media access commands have immediate status with a delayed
 * process. In case of a successful initiation of a media access packet command,
 * the DSC bit will be set when the actual execution of the command is finished.
 * Since the tape drive will not issue an interrupt, we have to poll for this
 * event. In this case, we define the request as "low priority request" by
 * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
 * exit the driver.
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 *
1210 1211
 * ide.c will then give higher priority to requests which originate from the
 * other device, until will change rq_status to RQ_ACTIVE.
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 *
1213
 * 4. When the packet command is finished, it will be checked for errors.
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 *
1215 1216 1217
 * 5. In case an error was found, we queue a request sense packet command in
 * front of the request queue and retry the operation up to
 * IDETAPE_MAX_PC_RETRIES times.
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 *
1219 1220 1221
 * 6. In case no error was found, or we decided to give up and not to retry
 * again, the callback function will be called and then we will handle the next
 * request.
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 */
static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
{
	ide_hwif_t *hwif = drive->hwif;
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t *pc = tape->pc;
	int retries = 100;
	ide_startstop_t startstop;
1230
	u8 ireason;
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1232 1233 1234
	if (ide_wait_stat(&startstop, drive, DRQ_STAT, BUSY_STAT, WAIT_READY)) {
		printk(KERN_ERR "ide-tape: Strange, packet command initiated "
				"yet DRQ isn't asserted\n");
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		return startstop;
	}
1237 1238
	ireason = hwif->INB(IDE_IREASON_REG);
	while (retries-- && ((ireason & CD) == 0 || (ireason & IO))) {
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		printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
				"a packet command, retrying\n");
		udelay(100);
1242
		ireason = hwif->INB(IDE_IREASON_REG);
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		if (retries == 0) {
			printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
					"issuing a packet command, ignoring\n");
1246 1247
			ireason |= CD;
			ireason &= ~IO;
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		}
	}
1250
	if ((ireason & CD) == 0 || (ireason & IO)) {
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		printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
				"a packet command\n");
		return ide_do_reset(drive);
	}
	/* Set the interrupt routine */
	ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
#ifdef CONFIG_BLK_DEV_IDEDMA
	/* Begin DMA, if necessary */
	if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags))
		hwif->dma_start(drive);
#endif
	/* Send the actual packet */
	HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
	return ide_started;
}

1267
static ide_startstop_t idetape_issue_pc(ide_drive_t *drive, idetape_pc_t *pc)
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{
	ide_hwif_t *hwif = drive->hwif;
	idetape_tape_t *tape = drive->driver_data;
	int dma_ok = 0;
1272
	u16 bcount;
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1274 1275
	if (tape->pc->c[0] == REQUEST_SENSE &&
	    pc->c[0] == REQUEST_SENSE) {
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		printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
			"Two request sense in serial were issued\n");
	}

1280
	if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
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		tape->failed_pc = pc;
	/* Set the current packet command */
	tape->pc = pc;

	if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
	    test_bit(PC_ABORT, &pc->flags)) {
		/*
1288 1289 1290
		 * We will "abort" retrying a packet command in case legitimate
		 * error code was received (crossing a filemark, or end of the
		 * media, for example).
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		 */
		if (!test_bit(PC_ABORT, &pc->flags)) {
1293
			if (!(pc->c[0] == TEST_UNIT_READY &&
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			      tape->sense_key == 2 && tape->asc == 4 &&
			     (tape->ascq == 1 || tape->ascq == 8))) {
				printk(KERN_ERR "ide-tape: %s: I/O error, "
						"pc = %2x, key = %2x, "
						"asc = %2x, ascq = %2x\n",
						tape->name, pc->c[0],
						tape->sense_key, tape->asc,
						tape->ascq);
			}
			/* Giving up */
			pc->error = IDETAPE_ERROR_GENERAL;
		}
		tape->failed_pc = NULL;
		return pc->callback(drive);
	}
1309
	debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
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	pc->retries++;
	/* We haven't transferred any data yet */
	pc->actually_transferred = 0;
	pc->current_position = pc->buffer;
	/* Request to transfer the entire buffer at once */
1316
	bcount = pc->request_transfer;
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	if (test_and_clear_bit(PC_DMA_ERROR, &pc->flags)) {
		printk(KERN_WARNING "ide-tape: DMA disabled, "
				"reverting to PIO\n");
1321
		ide_dma_off(drive);
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	}
	if (test_bit(PC_DMA_RECOMMENDED, &pc->flags) && drive->using_dma)
		dma_ok = !hwif->dma_setup(drive);

1326 1327 1328
	ide_pktcmd_tf_load(drive, IDE_TFLAG_NO_SELECT_MASK |
			   IDE_TFLAG_OUT_DEVICE, bcount, dma_ok);

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	if (dma_ok)			/* Will begin DMA later */
		set_bit(PC_DMA_IN_PROGRESS, &pc->flags);
	if (test_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags)) {
1332 1333
		ide_execute_command(drive, WIN_PACKETCMD, &idetape_transfer_pc,
				    IDETAPE_WAIT_CMD, NULL);
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		return ide_started;
	} else {
		hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
		return idetape_transfer_pc(drive);
	}
}

1341
static ide_startstop_t idetape_pc_callback(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;
1344 1345

	debug_log(DBG_PROCS, "Enter %s\n", __func__);
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	idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
	return ide_stopped;
}

1351
/* A mode sense command is used to "sense" tape parameters. */
1352
static void idetape_create_mode_sense_cmd(idetape_pc_t *pc, u8 page_code)
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{
	idetape_init_pc(pc);
1355
	pc->c[0] = MODE_SENSE;
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	if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
1357 1358
		/* DBD = 1 - Don't return block descriptors */
		pc->c[1] = 8;
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	pc->c[2] = page_code;
	/*
	 * Changed pc->c[3] to 0 (255 will at best return unused info).
	 *
	 * For SCSI this byte is defined as subpage instead of high byte
	 * of length and some IDE drives seem to interpret it this way
	 * and return an error when 255 is used.
	 */
	pc->c[3] = 0;
1368 1369
	/* We will just discard data in that case */
	pc->c[4] = 255;
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	if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
		pc->request_transfer = 12;
	else if (page_code == IDETAPE_CAPABILITIES_PAGE)
		pc->request_transfer = 24;
	else
		pc->request_transfer = 50;
	pc->callback = &idetape_pc_callback;
}

1379
static void idetape_calculate_speeds(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;

1383 1384 1385 1386 1387 1388
	if (time_after(jiffies,
			tape->controlled_pipeline_head_time + 120 * HZ)) {
		tape->controlled_previous_pipeline_head =
			tape->controlled_last_pipeline_head;
		tape->controlled_previous_head_time =
			tape->controlled_pipeline_head_time;
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		tape->controlled_last_pipeline_head = tape->pipeline_head;
		tape->controlled_pipeline_head_time = jiffies;
	}
	if (time_after(jiffies, tape->controlled_pipeline_head_time + 60 * HZ))
1393 1394 1395
		tape->controlled_pipeline_head_speed = (tape->pipeline_head -
				tape->controlled_last_pipeline_head) * 32 * HZ /
				(jiffies - tape->controlled_pipeline_head_time);
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	else if (time_after(jiffies, tape->controlled_previous_head_time))
1397 1398 1399
		tape->controlled_pipeline_head_speed = (tape->pipeline_head -
				tape->controlled_previous_pipeline_head) * 32 *
			HZ / (jiffies - tape->controlled_previous_head_time);
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1401
	if (tape->nr_pending_stages < tape->max_stages/*- 1 */) {
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		/* -1 for read mode error recovery */
1403 1404
		if (time_after(jiffies, tape->uncontrolled_previous_head_time +
					10 * HZ)) {
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			tape->uncontrolled_pipeline_head_time = jiffies;
1406 1407 1408 1409 1410
			tape->uncontrolled_pipeline_head_speed =
				(tape->pipeline_head -
				 tape->uncontrolled_previous_pipeline_head) *
				32 * HZ / (jiffies -
					tape->uncontrolled_previous_head_time);
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		}
	} else {
		tape->uncontrolled_previous_head_time = jiffies;
		tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;
1415 1416
		if (time_after(jiffies, tape->uncontrolled_pipeline_head_time +
					30 * HZ))
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			tape->uncontrolled_pipeline_head_time = jiffies;
1418

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	}
1420 1421
	tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed,
					tape->controlled_pipeline_head_speed);
1422 1423

	if (tape->speed_control == 1) {
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		if (tape->nr_pending_stages >= tape->max_stages / 2)
			tape->max_insert_speed = tape->pipeline_head_speed +
1426 1427 1428
				(1100 - tape->pipeline_head_speed) * 2 *
				(tape->nr_pending_stages - tape->max_stages / 2)
				/ tape->max_stages;
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		else
			tape->max_insert_speed = 500 +
1431 1432
				(tape->pipeline_head_speed - 500) * 2 *
				tape->nr_pending_stages / tape->max_stages;
1433

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		if (tape->nr_pending_stages >= tape->max_stages * 99 / 100)
			tape->max_insert_speed = 5000;
	} else
		tape->max_insert_speed = tape->speed_control;
1438

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	tape->max_insert_speed = max(tape->max_insert_speed, 500);
}

1442
static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t *pc = tape->pc;
1446
	u8 stat;
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1448 1449
	stat = ide_read_status(drive);

1450 1451
	if (stat & SEEK_STAT) {
		if (stat & ERR_STAT) {
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			/* Error detected */
1453
			if (pc->c[0] != TEST_UNIT_READY)
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				printk(KERN_ERR "ide-tape: %s: I/O error, ",
						tape->name);
			/* Retry operation */
			return idetape_retry_pc(drive);
		}
		pc->error = 0;
		if (tape->failed_pc == pc)
			tape->failed_pc = NULL;
	} else {
		pc->error = IDETAPE_ERROR_GENERAL;
		tape->failed_pc = NULL;
	}
	return pc->callback(drive);
}

1469
static ide_startstop_t idetape_rw_callback(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;
	struct request *rq = HWGROUP(drive)->rq;
1473
	int blocks = tape->pc->actually_transferred / tape->blk_size;
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1475 1476
	tape->avg_size += blocks * tape->blk_size;
	tape->insert_size += blocks * tape->blk_size;
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	if (tape->insert_size > 1024 * 1024)
		tape->measure_insert_time = 1;
	if (tape->measure_insert_time) {
		tape->measure_insert_time = 0;
		tape->insert_time = jiffies;
		tape->insert_size = 0;
	}
	if (time_after(jiffies, tape->insert_time))
1485 1486
		tape->insert_speed = tape->insert_size / 1024 * HZ /
					(jiffies - tape->insert_time);
1487
	if (time_after_eq(jiffies, tape->avg_time + HZ)) {
1488 1489
		tape->avg_speed = tape->avg_size * HZ /
				(jiffies - tape->avg_time) / 1024;
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		tape->avg_size = 0;
		tape->avg_time = jiffies;
	}
1493
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
L
Linus Torvalds 已提交
1494

1495
	tape->first_frame += blocks;
L
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1496 1497 1498 1499 1500 1501 1502 1503 1504
	rq->current_nr_sectors -= blocks;

	if (!tape->pc->error)
		idetape_end_request(drive, 1, 0);
	else
		idetape_end_request(drive, tape->pc->error, 0);
	return ide_stopped;
}

1505 1506
static void idetape_create_read_cmd(idetape_tape_t *tape, idetape_pc_t *pc,
		unsigned int length, struct idetape_bh *bh)
L
Linus Torvalds 已提交
1507 1508
{
	idetape_init_pc(pc);
1509
	pc->c[0] = READ_6;
1510
	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
L
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1511 1512 1513 1514 1515
	pc->c[1] = 1;
	pc->callback = &idetape_rw_callback;
	pc->bh = bh;
	atomic_set(&bh->b_count, 0);
	pc->buffer = NULL;
1516 1517
	pc->buffer_size = length * tape->blk_size;
	pc->request_transfer = pc->buffer_size;
L
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1518 1519 1520 1521
	if (pc->request_transfer == tape->stage_size)
		set_bit(PC_DMA_RECOMMENDED, &pc->flags);
}

1522 1523
static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc,
		unsigned int length, struct idetape_bh *bh)
L
Linus Torvalds 已提交
1524 1525
{
	idetape_init_pc(pc);
1526
	pc->c[0] = WRITE_6;
1527
	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
L
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1528 1529 1530 1531 1532 1533 1534
	pc->c[1] = 1;
	pc->callback = &idetape_rw_callback;
	set_bit(PC_WRITING, &pc->flags);
	pc->bh = bh;
	pc->b_data = bh->b_data;
	pc->b_count = atomic_read(&bh->b_count);
	pc->buffer = NULL;
1535 1536
	pc->buffer_size = length * tape->blk_size;
	pc->request_transfer = pc->buffer_size;
L
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1537 1538 1539 1540 1541 1542 1543 1544 1545 1546
	if (pc->request_transfer == tape->stage_size)
		set_bit(PC_DMA_RECOMMENDED, &pc->flags);
}

static ide_startstop_t idetape_do_request(ide_drive_t *drive,
					  struct request *rq, sector_t block)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t *pc = NULL;
	struct request *postponed_rq = tape->postponed_rq;
1547
	u8 stat;
L
Linus Torvalds 已提交
1548

1549 1550
	debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
			" current_nr_sectors: %d\n",
L
Linus Torvalds 已提交
1551 1552
			rq->sector, rq->nr_sectors, rq->current_nr_sectors);

1553
	if (!blk_special_request(rq)) {
1554
		/* We do not support buffer cache originated requests. */
L
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1555
		printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1556
			"request queue (%d)\n", drive->name, rq->cmd_type);
L
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1557 1558 1559 1560
		ide_end_request(drive, 0, 0);
		return ide_stopped;
	}

1561
	/* Retry a failed packet command */
1562
	if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE)
1563
		return idetape_issue_pc(drive, tape->failed_pc);
1564

L
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1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578
	if (postponed_rq != NULL)
		if (rq != postponed_rq) {
			printk(KERN_ERR "ide-tape: ide-tape.c bug - "
					"Two DSC requests were queued\n");
			idetape_end_request(drive, 0, 0);
			return ide_stopped;
		}

	tape->postponed_rq = NULL;

	/*
	 * If the tape is still busy, postpone our request and service
	 * the other device meanwhile.
	 */
1579
	stat = ide_read_status(drive);
L
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1580 1581 1582 1583 1584 1585 1586 1587 1588 1589

	if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
		set_bit(IDETAPE_IGNORE_DSC, &tape->flags);

	if (drive->post_reset == 1) {
		set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
		drive->post_reset = 0;
	}

	if (time_after(jiffies, tape->insert_time))
1590 1591
		tape->insert_speed = tape->insert_size / 1024 * HZ /
					(jiffies - tape->insert_time);
1592
	idetape_calculate_speeds(drive);
L
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1593
	if (!test_and_clear_bit(IDETAPE_IGNORE_DSC, &tape->flags) &&
1594
	    (stat & SEEK_STAT) == 0) {
L
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1595 1596
		if (postponed_rq == NULL) {
			tape->dsc_polling_start = jiffies;
1597
			tape->dsc_poll_freq = tape->best_dsc_rw_freq;
L
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1598 1599 1600 1601 1602 1603 1604 1605 1606 1607
			tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
		} else if (time_after(jiffies, tape->dsc_timeout)) {
			printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
				tape->name);
			if (rq->cmd[0] & REQ_IDETAPE_PC2) {
				idetape_media_access_finished(drive);
				return ide_stopped;
			} else {
				return ide_do_reset(drive);
			}
1608 1609 1610
		} else if (time_after(jiffies,
					tape->dsc_polling_start +
					IDETAPE_DSC_MA_THRESHOLD))
1611
			tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
L
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1612 1613 1614 1615 1616 1617 1618
		idetape_postpone_request(drive);
		return ide_stopped;
	}
	if (rq->cmd[0] & REQ_IDETAPE_READ) {
		tape->buffer_head++;
		tape->postpone_cnt = 0;
		pc = idetape_next_pc_storage(drive);
1619 1620
		idetape_create_read_cmd(tape, pc, rq->current_nr_sectors,
					(struct idetape_bh *)rq->special);
L
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1621 1622 1623 1624 1625 1626
		goto out;
	}
	if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
		tape->buffer_head++;
		tape->postpone_cnt = 0;
		pc = idetape_next_pc_storage(drive);
1627 1628
		idetape_create_write_cmd(tape, pc, rq->current_nr_sectors,
					 (struct idetape_bh *)rq->special);
L
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1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642
		goto out;
	}
	if (rq->cmd[0] & REQ_IDETAPE_PC1) {
		pc = (idetape_pc_t *) rq->buffer;
		rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
		rq->cmd[0] |= REQ_IDETAPE_PC2;
		goto out;
	}
	if (rq->cmd[0] & REQ_IDETAPE_PC2) {
		idetape_media_access_finished(drive);
		return ide_stopped;
	}
	BUG();
out:
1643
	return idetape_issue_pc(drive, pc);
L
Linus Torvalds 已提交
1644 1645
}

1646
/* Pipeline related functions */
1647
static inline int idetape_pipeline_active(idetape_tape_t *tape)
L
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1648 1649 1650 1651
{
	int rc1, rc2;

	rc1 = test_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
1652
	rc2 = (tape->active_data_rq != NULL);
L
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1653 1654 1655 1656
	return rc1;
}

/*
1657 1658 1659 1660
 * The function below uses __get_free_page to allocate a pipeline stage, along
 * with all the necessary small buffers which together make a buffer of size
 * tape->stage_size (or a bit more). We attempt to combine sequential pages as
 * much as possible.
L
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1661
 *
1662 1663
 * It returns a pointer to the new allocated stage, or NULL if we can't (or
 * don't want to) allocate a stage.
L
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1664
 *
1665 1666
 * Pipeline stages are optional and are used to increase performance. If we
 * can't allocate them, we'll manage without them.
L
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1667
 */
1668 1669
static idetape_stage_t *__idetape_kmalloc_stage(idetape_tape_t *tape, int full,
						int clear)
L
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1670 1671 1672 1673 1674 1675
{
	idetape_stage_t *stage;
	struct idetape_bh *prev_bh, *bh;
	int pages = tape->pages_per_stage;
	char *b_data = NULL;

1676 1677
	stage = kmalloc(sizeof(idetape_stage_t), GFP_KERNEL);
	if (!stage)
L
Linus Torvalds 已提交
1678 1679 1680
		return NULL;
	stage->next = NULL;

1681 1682
	stage->bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
	bh = stage->bh;
L
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1683 1684 1685
	if (bh == NULL)
		goto abort;
	bh->b_reqnext = NULL;
1686 1687
	bh->b_data = (char *) __get_free_page(GFP_KERNEL);
	if (!bh->b_data)
L
Linus Torvalds 已提交
1688 1689 1690 1691 1692 1693 1694
		goto abort;
	if (clear)
		memset(bh->b_data, 0, PAGE_SIZE);
	bh->b_size = PAGE_SIZE;
	atomic_set(&bh->b_count, full ? bh->b_size : 0);

	while (--pages) {
1695 1696
		b_data = (char *) __get_free_page(GFP_KERNEL);
		if (!b_data)
L
Linus Torvalds 已提交
1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713
			goto abort;
		if (clear)
			memset(b_data, 0, PAGE_SIZE);
		if (bh->b_data == b_data + PAGE_SIZE) {
			bh->b_size += PAGE_SIZE;
			bh->b_data -= PAGE_SIZE;
			if (full)
				atomic_add(PAGE_SIZE, &bh->b_count);
			continue;
		}
		if (b_data == bh->b_data + bh->b_size) {
			bh->b_size += PAGE_SIZE;
			if (full)
				atomic_add(PAGE_SIZE, &bh->b_count);
			continue;
		}
		prev_bh = bh;
1714 1715
		bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
		if (!bh) {
L
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1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733
			free_page((unsigned long) b_data);
			goto abort;
		}
		bh->b_reqnext = NULL;
		bh->b_data = b_data;
		bh->b_size = PAGE_SIZE;
		atomic_set(&bh->b_count, full ? bh->b_size : 0);
		prev_bh->b_reqnext = bh;
	}
	bh->b_size -= tape->excess_bh_size;
	if (full)
		atomic_sub(tape->excess_bh_size, &bh->b_count);
	return stage;
abort:
	__idetape_kfree_stage(stage);
	return NULL;
}

1734
static idetape_stage_t *idetape_kmalloc_stage(idetape_tape_t *tape)
L
Linus Torvalds 已提交
1735 1736 1737
{
	idetape_stage_t *cache_stage = tape->cache_stage;

1738
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
L
Linus Torvalds 已提交
1739 1740 1741 1742 1743 1744 1745 1746 1747 1748

	if (tape->nr_stages >= tape->max_stages)
		return NULL;
	if (cache_stage != NULL) {
		tape->cache_stage = NULL;
		return cache_stage;
	}
	return __idetape_kmalloc_stage(tape, 0, 0);
}

1749 1750
static int idetape_copy_stage_from_user(idetape_tape_t *tape,
		idetape_stage_t *stage, const char __user *buf, int n)
L
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1751 1752 1753
{
	struct idetape_bh *bh = tape->bh;
	int count;
1754
	int ret = 0;
L
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1755 1756 1757

	while (n) {
		if (bh == NULL) {
1758 1759
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
1760
			return 1;
L
Linus Torvalds 已提交
1761
		}
1762 1763 1764 1765 1766
		count = min((unsigned int)
				(bh->b_size - atomic_read(&bh->b_count)),
				(unsigned int)n);
		if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
				count))
1767
			ret = 1;
L
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1768 1769 1770 1771 1772 1773 1774 1775 1776 1777
		n -= count;
		atomic_add(count, &bh->b_count);
		buf += count;
		if (atomic_read(&bh->b_count) == bh->b_size) {
			bh = bh->b_reqnext;
			if (bh)
				atomic_set(&bh->b_count, 0);
		}
	}
	tape->bh = bh;
1778
	return ret;
L
Linus Torvalds 已提交
1779 1780
}

1781 1782
static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
		idetape_stage_t *stage, int n)
L
Linus Torvalds 已提交
1783 1784 1785
{
	struct idetape_bh *bh = tape->bh;
	int count;
1786
	int ret = 0;
L
Linus Torvalds 已提交
1787 1788 1789

	while (n) {
		if (bh == NULL) {
1790 1791
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
1792
			return 1;
L
Linus Torvalds 已提交
1793 1794
		}
		count = min(tape->b_count, n);
1795 1796
		if  (copy_to_user(buf, tape->b_data, count))
			ret = 1;
L
Linus Torvalds 已提交
1797 1798 1799 1800 1801
		n -= count;
		tape->b_data += count;
		tape->b_count -= count;
		buf += count;
		if (!tape->b_count) {
1802 1803
			bh = bh->b_reqnext;
			tape->bh = bh;
L
Linus Torvalds 已提交
1804 1805 1806 1807 1808 1809
			if (bh) {
				tape->b_data = bh->b_data;
				tape->b_count = atomic_read(&bh->b_count);
			}
		}
	}
1810
	return ret;
L
Linus Torvalds 已提交
1811 1812
}

1813
static void idetape_init_merge_stage(idetape_tape_t *tape)
L
Linus Torvalds 已提交
1814 1815
{
	struct idetape_bh *bh = tape->merge_stage->bh;
1816

L
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1817
	tape->bh = bh;
1818
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
L
Linus Torvalds 已提交
1819 1820 1821 1822 1823 1824 1825
		atomic_set(&bh->b_count, 0);
	else {
		tape->b_data = bh->b_data;
		tape->b_count = atomic_read(&bh->b_count);
	}
}

1826
static void idetape_switch_buffers(idetape_tape_t *tape, idetape_stage_t *stage)
L
Linus Torvalds 已提交
1827 1828 1829 1830 1831 1832 1833 1834 1835
{
	struct idetape_bh *tmp;

	tmp = stage->bh;
	stage->bh = tape->merge_stage->bh;
	tape->merge_stage->bh = tmp;
	idetape_init_merge_stage(tape);
}

1836
/* Add a new stage at the end of the pipeline. */
1837
static void idetape_add_stage_tail(ide_drive_t *drive, idetape_stage_t *stage)
L
Linus Torvalds 已提交
1838 1839 1840
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;
1841 1842 1843

	debug_log(DBG_PROCS, "Enter %s\n", __func__);

1844
	spin_lock_irqsave(&tape->lock, flags);
L
Linus Torvalds 已提交
1845 1846
	stage->next = NULL;
	if (tape->last_stage != NULL)
1847
		tape->last_stage->next = stage;
L
Linus Torvalds 已提交
1848
	else
1849 1850
		tape->first_stage = stage;
		tape->next_stage  = stage;
L
Linus Torvalds 已提交
1851 1852 1853 1854 1855
	tape->last_stage = stage;
	if (tape->next_stage == NULL)
		tape->next_stage = tape->last_stage;
	tape->nr_stages++;
	tape->nr_pending_stages++;
1856
	spin_unlock_irqrestore(&tape->lock, flags);
L
Linus Torvalds 已提交
1857 1858
}

1859 1860 1861
/* Install a completion in a pending request and sleep until it is serviced. The
 * caller should ensure that the request will not be serviced before we install
 * the completion (usually by disabling interrupts).
L
Linus Torvalds 已提交
1862
 */
1863
static void idetape_wait_for_request(ide_drive_t *drive, struct request *rq)
L
Linus Torvalds 已提交
1864
{
1865
	DECLARE_COMPLETION_ONSTACK(wait);
L
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1866 1867
	idetape_tape_t *tape = drive->driver_data;

1868
	if (rq == NULL || !blk_special_request(rq)) {
1869 1870
		printk(KERN_ERR "ide-tape: bug: Trying to sleep on non-valid"
				 " request\n");
L
Linus Torvalds 已提交
1871 1872
		return;
	}
1873
	rq->end_io_data = &wait;
L
Linus Torvalds 已提交
1874
	rq->end_io = blk_end_sync_rq;
1875
	spin_unlock_irq(&tape->lock);
L
Linus Torvalds 已提交
1876 1877
	wait_for_completion(&wait);
	/* The stage and its struct request have been deallocated */
1878
	spin_lock_irq(&tape->lock);
L
Linus Torvalds 已提交
1879 1880
}

1881
static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
L
Linus Torvalds 已提交
1882 1883
{
	idetape_tape_t *tape = drive->driver_data;
1884
	u8 *readpos = tape->pc->buffer;
1885 1886

	debug_log(DBG_PROCS, "Enter %s\n", __func__);
L
Linus Torvalds 已提交
1887 1888

	if (!tape->pc->error) {
1889 1890 1891 1892 1893 1894 1895 1896
		debug_log(DBG_SENSE, "BOP - %s\n",
				(readpos[0] & 0x80) ? "Yes" : "No");
		debug_log(DBG_SENSE, "EOP - %s\n",
				(readpos[0] & 0x40) ? "Yes" : "No");

		if (readpos[0] & 0x4) {
			printk(KERN_INFO "ide-tape: Block location is unknown"
					 "to the tape\n");
L
Linus Torvalds 已提交
1897 1898 1899
			clear_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
			idetape_end_request(drive, 0, 0);
		} else {
1900
			debug_log(DBG_SENSE, "Block Location - %u\n",
1901 1902 1903
					be32_to_cpu(*(u32 *)&readpos[4]));

			tape->partition = readpos[1];
1904
			tape->first_frame =
1905
				be32_to_cpu(*(u32 *)&readpos[4]);
L
Linus Torvalds 已提交
1906 1907 1908 1909 1910 1911 1912 1913 1914 1915
			set_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
			idetape_end_request(drive, 1, 0);
		}
	} else {
		idetape_end_request(drive, 0, 0);
	}
	return ide_stopped;
}

/*
1916 1917
 * Write a filemark if write_filemark=1. Flush the device buffers without
 * writing a filemark otherwise.
L
Linus Torvalds 已提交
1918
 */
1919 1920
static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
		idetape_pc_t *pc, int write_filemark)
L
Linus Torvalds 已提交
1921 1922
{
	idetape_init_pc(pc);
1923
	pc->c[0] = WRITE_FILEMARKS;
L
Linus Torvalds 已提交
1924 1925 1926 1927 1928 1929 1930 1931
	pc->c[4] = write_filemark;
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc)
{
	idetape_init_pc(pc);
1932
	pc->c[0] = TEST_UNIT_READY;
L
Linus Torvalds 已提交
1933 1934 1935 1936
	pc->callback = &idetape_pc_callback;
}

/*
1937 1938 1939 1940 1941 1942
 * We add a special packet command request to the tail of the request queue, and
 * wait for it to be serviced. This is not to be called from within the request
 * handling part of the driver! We allocate here data on the stack and it is
 * valid until the request is finished. This is not the case for the bottom part
 * of the driver, where we are always leaving the functions to wait for an
 * interrupt or a timer event.
L
Linus Torvalds 已提交
1943
 *
1944 1945 1946 1947
 * From the bottom part of the driver, we should allocate safe memory using
 * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
 * to the request list without waiting for it to be serviced! In that case, we
 * usually use idetape_queue_pc_head().
L
Linus Torvalds 已提交
1948
 */
1949
static int __idetape_queue_pc_tail(ide_drive_t *drive, idetape_pc_t *pc)
L
Linus Torvalds 已提交
1950 1951 1952 1953 1954 1955 1956 1957 1958 1959
{
	struct ide_tape_obj *tape = drive->driver_data;
	struct request rq;

	idetape_init_rq(&rq, REQ_IDETAPE_PC1);
	rq.buffer = (char *) pc;
	rq.rq_disk = tape->disk;
	return ide_do_drive_cmd(drive, &rq, ide_wait);
}

1960 1961
static void idetape_create_load_unload_cmd(ide_drive_t *drive, idetape_pc_t *pc,
		int cmd)
L
Linus Torvalds 已提交
1962 1963
{
	idetape_init_pc(pc);
1964
	pc->c[0] = START_STOP;
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	pc->c[4] = cmd;
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
	int load_attempted = 0;

1976
	/* Wait for the tape to become ready */
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	set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
	timeout += jiffies;
	while (time_before(jiffies, timeout)) {
		idetape_create_test_unit_ready_cmd(&pc);
		if (!__idetape_queue_pc_tail(drive, &pc))
			return 0;
		if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1984 1985
		    || (tape->asc == 0x3A)) {
			/* no media */
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			if (load_attempted)
				return -ENOMEDIUM;
1988 1989
			idetape_create_load_unload_cmd(drive, &pc,
							IDETAPE_LU_LOAD_MASK);
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			__idetape_queue_pc_tail(drive, &pc);
			load_attempted = 1;
		/* not about to be ready */
		} else if (!(tape->sense_key == 2 && tape->asc == 4 &&
			     (tape->ascq == 1 || tape->ascq == 8)))
			return -EIO;
1996
		msleep(100);
L
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	}
	return -EIO;
}

2001
static int idetape_queue_pc_tail(ide_drive_t *drive, idetape_pc_t *pc)
L
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2002 2003 2004 2005
{
	return __idetape_queue_pc_tail(drive, pc);
}

2006
static int idetape_flush_tape_buffers(ide_drive_t *drive)
L
Linus Torvalds 已提交
2007 2008 2009 2010 2011
{
	idetape_pc_t pc;
	int rc;

	idetape_create_write_filemark_cmd(drive, &pc, 0);
2012 2013
	rc = idetape_queue_pc_tail(drive, &pc);
	if (rc)
L
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2014 2015 2016 2017 2018
		return rc;
	idetape_wait_ready(drive, 60 * 5 * HZ);
	return 0;
}

2019
static void idetape_create_read_position_cmd(idetape_pc_t *pc)
L
Linus Torvalds 已提交
2020 2021
{
	idetape_init_pc(pc);
2022
	pc->c[0] = READ_POSITION;
L
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2023 2024 2025 2026
	pc->request_transfer = 20;
	pc->callback = &idetape_read_position_callback;
}

2027
static int idetape_read_position(ide_drive_t *drive)
L
Linus Torvalds 已提交
2028 2029 2030 2031 2032
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
	int position;

2033
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
L
Linus Torvalds 已提交
2034 2035 2036 2037

	idetape_create_read_position_cmd(&pc);
	if (idetape_queue_pc_tail(drive, &pc))
		return -1;
2038
	position = tape->first_frame;
L
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2039 2040 2041
	return position;
}

2042 2043
static void idetape_create_locate_cmd(ide_drive_t *drive, idetape_pc_t *pc,
		unsigned int block, u8 partition, int skip)
L
Linus Torvalds 已提交
2044 2045
{
	idetape_init_pc(pc);
2046
	pc->c[0] = POSITION_TO_ELEMENT;
L
Linus Torvalds 已提交
2047
	pc->c[1] = 2;
2048
	put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
L
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2049 2050 2051 2052 2053
	pc->c[8] = partition;
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

2054 2055
static int idetape_create_prevent_cmd(ide_drive_t *drive, idetape_pc_t *pc,
				      int prevent)
L
Linus Torvalds 已提交
2056 2057 2058
{
	idetape_tape_t *tape = drive->driver_data;

2059 2060
	/* device supports locking according to capabilities page */
	if (!(tape->caps[6] & 0x01))
L
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2061 2062 2063
		return 0;

	idetape_init_pc(pc);
2064
	pc->c[0] = ALLOW_MEDIUM_REMOVAL;
L
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2065 2066 2067 2068 2069
	pc->c[4] = prevent;
	pc->callback = &idetape_pc_callback;
	return 1;
}

2070
static int __idetape_discard_read_pipeline(ide_drive_t *drive)
L
Linus Torvalds 已提交
2071 2072 2073 2074 2075
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;
	int cnt;

2076
	if (tape->chrdev_dir != IDETAPE_DIR_READ)
L
Linus Torvalds 已提交
2077 2078 2079
		return 0;

	/* Remove merge stage. */
2080
	cnt = tape->merge_stage_size / tape->blk_size;
L
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2081 2082 2083 2084 2085 2086 2087 2088 2089 2090
	if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
		++cnt;		/* Filemarks count as 1 sector */
	tape->merge_stage_size = 0;
	if (tape->merge_stage != NULL) {
		__idetape_kfree_stage(tape->merge_stage);
		tape->merge_stage = NULL;
	}

	/* Clear pipeline flags. */
	clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
2091
	tape->chrdev_dir = IDETAPE_DIR_NONE;
L
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2092 2093 2094 2095 2096

	/* Remove pipeline stages. */
	if (tape->first_stage == NULL)
		return 0;

2097
	spin_lock_irqsave(&tape->lock, flags);
L
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2098 2099
	tape->next_stage = NULL;
	if (idetape_pipeline_active(tape))
2100 2101
		idetape_wait_for_request(drive, tape->active_data_rq);
	spin_unlock_irqrestore(&tape->lock, flags);
L
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2102 2103 2104 2105

	while (tape->first_stage != NULL) {
		struct request *rq_ptr = &tape->first_stage->rq;

2106
		cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors;
L
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2107 2108 2109 2110 2111 2112 2113 2114 2115 2116
		if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
			++cnt;
		idetape_remove_stage_head(drive);
	}
	tape->nr_pending_stages = 0;
	tape->max_stages = tape->min_pipeline;
	return cnt;
}

/*
2117 2118 2119 2120
 * Position the tape to the requested block using the LOCATE packet command.
 * A READ POSITION command is then issued to check where we are positioned. Like
 * all higher level operations, we queue the commands at the tail of the request
 * queue and wait for their completion.
L
Linus Torvalds 已提交
2121
 */
2122 2123
static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
		u8 partition, int skip)
L
Linus Torvalds 已提交
2124 2125 2126 2127 2128
{
	idetape_tape_t *tape = drive->driver_data;
	int retval;
	idetape_pc_t pc;

2129
	if (tape->chrdev_dir == IDETAPE_DIR_READ)
L
Linus Torvalds 已提交
2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140
		__idetape_discard_read_pipeline(drive);
	idetape_wait_ready(drive, 60 * 5 * HZ);
	idetape_create_locate_cmd(drive, &pc, block, partition, skip);
	retval = idetape_queue_pc_tail(drive, &pc);
	if (retval)
		return (retval);

	idetape_create_read_position_cmd(&pc);
	return (idetape_queue_pc_tail(drive, &pc));
}

2141 2142
static void idetape_discard_read_pipeline(ide_drive_t *drive,
					  int restore_position)
L
Linus Torvalds 已提交
2143 2144 2145 2146 2147 2148 2149 2150 2151 2152
{
	idetape_tape_t *tape = drive->driver_data;
	int cnt;
	int seek, position;

	cnt = __idetape_discard_read_pipeline(drive);
	if (restore_position) {
		position = idetape_read_position(drive);
		seek = position > cnt ? position - cnt : 0;
		if (idetape_position_tape(drive, seek, 0, 0)) {
2153 2154
			printk(KERN_INFO "ide-tape: %s: position_tape failed in"
					 " discard_pipeline()\n", tape->name);
L
Linus Torvalds 已提交
2155 2156 2157 2158 2159 2160
			return;
		}
	}
}

/*
2161 2162
 * Generate a read/write request for the block device interface and wait for it
 * to be serviced.
L
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2163
 */
2164 2165
static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
				 struct idetape_bh *bh)
L
Linus Torvalds 已提交
2166 2167 2168 2169
{
	idetape_tape_t *tape = drive->driver_data;
	struct request rq;

2170 2171
	debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);

L
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2172
	if (idetape_pipeline_active(tape)) {
2173 2174
		printk(KERN_ERR "ide-tape: bug: the pipeline is active in %s\n",
				__func__);
L
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2175 2176 2177 2178 2179 2180
		return (0);
	}

	idetape_init_rq(&rq, cmd);
	rq.rq_disk = tape->disk;
	rq.special = (void *)bh;
2181
	rq.sector = tape->first_frame;
2182 2183
	rq.nr_sectors		= blocks;
	rq.current_nr_sectors	= blocks;
L
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2184 2185 2186 2187 2188 2189 2190 2191 2192
	(void) ide_do_drive_cmd(drive, &rq, ide_wait);

	if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
		return 0;

	if (tape->merge_stage)
		idetape_init_merge_stage(tape);
	if (rq.errors == IDETAPE_ERROR_GENERAL)
		return -EIO;
2193
	return (tape->blk_size * (blocks-rq.current_nr_sectors));
L
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2194 2195
}

2196 2197
/* start servicing the pipeline stages, starting from tape->next_stage. */
static void idetape_plug_pipeline(ide_drive_t *drive)
L
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2198 2199 2200 2201 2202 2203 2204
{
	idetape_tape_t *tape = drive->driver_data;

	if (tape->next_stage == NULL)
		return;
	if (!idetape_pipeline_active(tape)) {
		set_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
2205
		idetape_activate_next_stage(drive);
2206
		(void) ide_do_drive_cmd(drive, tape->active_data_rq, ide_end);
L
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2207 2208 2209
	}
}

2210
static void idetape_create_inquiry_cmd(idetape_pc_t *pc)
L
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2211 2212
{
	idetape_init_pc(pc);
2213
	pc->c[0] = INQUIRY;
2214 2215
	pc->c[4] = 254;
	pc->request_transfer = 254;
L
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2216 2217 2218
	pc->callback = &idetape_pc_callback;
}

2219
static void idetape_create_rewind_cmd(ide_drive_t *drive, idetape_pc_t *pc)
L
Linus Torvalds 已提交
2220 2221
{
	idetape_init_pc(pc);
2222
	pc->c[0] = REZERO_UNIT;
L
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2223 2224 2225 2226
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

2227
static void idetape_create_erase_cmd(idetape_pc_t *pc)
L
Linus Torvalds 已提交
2228 2229
{
	idetape_init_pc(pc);
2230
	pc->c[0] = ERASE;
L
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2231 2232 2233 2234 2235
	pc->c[1] = 1;
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

2236
static void idetape_create_space_cmd(idetape_pc_t *pc, int count, u8 cmd)
L
Linus Torvalds 已提交
2237 2238
{
	idetape_init_pc(pc);
2239
	pc->c[0] = SPACE;
2240
	put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
L
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2241 2242 2243 2244 2245
	pc->c[1] = cmd;
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

2246
static void idetape_wait_first_stage(ide_drive_t *drive)
L
Linus Torvalds 已提交
2247 2248 2249 2250 2251 2252
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;

	if (tape->first_stage == NULL)
		return;
2253
	spin_lock_irqsave(&tape->lock, flags);
L
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2254
	if (tape->active_stage == tape->first_stage)
2255 2256
		idetape_wait_for_request(drive, tape->active_data_rq);
	spin_unlock_irqrestore(&tape->lock, flags);
L
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2257 2258 2259
}

/*
2260 2261 2262
 * Try to add a character device originated write request to our pipeline. In
 * case we don't succeed, we revert to non-pipelined operation mode for this
 * request. In order to accomplish that, we
L
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2263
 *
2264 2265 2266 2267 2268
 * 1. Try to allocate a new pipeline stage.
 * 2. If we can't, wait for more and more requests to be serviced and try again
 * each time.
 * 3. If we still can't allocate a stage, fallback to non-pipelined operation
 * mode for this request.
L
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2269
 */
2270
static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
L
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2271 2272 2273 2274 2275 2276
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *new_stage;
	unsigned long flags;
	struct request *rq;

2277
	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
L
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2278

2279
	/* Attempt to allocate a new stage. Beware possible race conditions. */
L
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2280
	while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
2281
		spin_lock_irqsave(&tape->lock, flags);
L
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2282
		if (idetape_pipeline_active(tape)) {
2283 2284
			idetape_wait_for_request(drive, tape->active_data_rq);
			spin_unlock_irqrestore(&tape->lock, flags);
L
Linus Torvalds 已提交
2285
		} else {
2286
			spin_unlock_irqrestore(&tape->lock, flags);
2287
			idetape_plug_pipeline(drive);
L
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2288 2289 2290
			if (idetape_pipeline_active(tape))
				continue;
			/*
2291 2292
			 * The machine is short on memory. Fallback to non-
			 * pipelined operation mode for this request.
L
Linus Torvalds 已提交
2293
			 */
2294 2295
			return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
						blocks, tape->merge_stage->bh);
L
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2296 2297 2298 2299 2300
		}
	}
	rq = &new_stage->rq;
	idetape_init_rq(rq, REQ_IDETAPE_WRITE);
	/* Doesn't actually matter - We always assume sequential access */
2301
	rq->sector = tape->first_frame;
2302 2303
	rq->current_nr_sectors = blocks;
	rq->nr_sectors = blocks;
L
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2304 2305 2306 2307

	idetape_switch_buffers(tape, new_stage);
	idetape_add_stage_tail(drive, new_stage);
	tape->pipeline_head++;
2308
	idetape_calculate_speeds(drive);
L
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2309 2310

	/*
2311 2312 2313 2314 2315
	 * Estimate whether the tape has stopped writing by checking if our
	 * write pipeline is currently empty. If we are not writing anymore,
	 * wait for the pipeline to be almost completely full (90%) before
	 * starting to service requests, so that we will be able to keep up with
	 * the higher speeds of the tape.
L
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2316 2317 2318
	 */
	if (!idetape_pipeline_active(tape)) {
		if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
2319 2320 2321
			tape->nr_stages >= tape->max_stages -
			tape->uncontrolled_pipeline_head_speed * 3 * 1024 /
			tape->blk_size) {
L
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2322 2323 2324 2325
			tape->measure_insert_time = 1;
			tape->insert_time = jiffies;
			tape->insert_size = 0;
			tape->insert_speed = 0;
2326
			idetape_plug_pipeline(drive);
L
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2327 2328 2329 2330 2331 2332 2333 2334 2335
		}
	}
	if (test_and_clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
		/* Return a deferred error */
		return -EIO;
	return blocks;
}

/*
2336 2337
 * Wait until all pending pipeline requests are serviced. Typically called on
 * device close.
L
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2338
 */
2339
static void idetape_wait_for_pipeline(ide_drive_t *drive)
L
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2340 2341 2342 2343 2344
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;

	while (tape->next_stage || idetape_pipeline_active(tape)) {
2345
		idetape_plug_pipeline(drive);
2346
		spin_lock_irqsave(&tape->lock, flags);
L
Linus Torvalds 已提交
2347
		if (idetape_pipeline_active(tape))
2348 2349
			idetape_wait_for_request(drive, tape->active_data_rq);
		spin_unlock_irqrestore(&tape->lock, flags);
L
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2350 2351 2352
	}
}

2353
static void idetape_empty_write_pipeline(ide_drive_t *drive)
L
Linus Torvalds 已提交
2354 2355 2356 2357
{
	idetape_tape_t *tape = drive->driver_data;
	int blocks, min;
	struct idetape_bh *bh;
2358

2359
	if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
2360 2361
		printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline,"
				" but we are not writing.\n");
L
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2362 2363 2364 2365 2366 2367 2368
		return;
	}
	if (tape->merge_stage_size > tape->stage_size) {
		printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
		tape->merge_stage_size = tape->stage_size;
	}
	if (tape->merge_stage_size) {
2369 2370
		blocks = tape->merge_stage_size / tape->blk_size;
		if (tape->merge_stage_size % tape->blk_size) {
L
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2371 2372 2373
			unsigned int i;

			blocks++;
2374 2375
			i = tape->blk_size - tape->merge_stage_size %
				tape->blk_size;
L
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2376 2377 2378 2379 2380 2381 2382 2383
			bh = tape->bh->b_reqnext;
			while (bh) {
				atomic_set(&bh->b_count, 0);
				bh = bh->b_reqnext;
			}
			bh = tape->bh;
			while (i) {
				if (bh == NULL) {
2384 2385
					printk(KERN_INFO "ide-tape: bug,"
							 " bh NULL\n");
L
Linus Torvalds 已提交
2386 2387
					break;
				}
2388 2389 2390 2391
				min = min(i, (unsigned int)(bh->b_size -
						atomic_read(&bh->b_count)));
				memset(bh->b_data + atomic_read(&bh->b_count),
						0, min);
L
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2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405
				atomic_add(min, &bh->b_count);
				i -= min;
				bh = bh->b_reqnext;
			}
		}
		(void) idetape_add_chrdev_write_request(drive, blocks);
		tape->merge_stage_size = 0;
	}
	idetape_wait_for_pipeline(drive);
	if (tape->merge_stage != NULL) {
		__idetape_kfree_stage(tape->merge_stage);
		tape->merge_stage = NULL;
	}
	clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
2406
	tape->chrdev_dir = IDETAPE_DIR_NONE;
L
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2407 2408

	/*
2409 2410 2411 2412
	 * On the next backup, perform the feedback loop again. (I don't want to
	 * keep sense information between backups, as some systems are
	 * constantly on, and the system load can be totally different on the
	 * next backup).
L
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2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426
	 */
	tape->max_stages = tape->min_pipeline;
	if (tape->first_stage != NULL ||
	    tape->next_stage != NULL ||
	    tape->last_stage != NULL ||
	    tape->nr_stages != 0) {
		printk(KERN_ERR "ide-tape: ide-tape pipeline bug, "
			"first_stage %p, next_stage %p, "
			"last_stage %p, nr_stages %d\n",
			tape->first_stage, tape->next_stage,
			tape->last_stage, tape->nr_stages);
	}
}

2427
static void idetape_restart_speed_control(ide_drive_t *drive)
L
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2428 2429 2430 2431 2432
{
	idetape_tape_t *tape = drive->driver_data;

	tape->restart_speed_control_req = 0;
	tape->pipeline_head = 0;
2433
	tape->controlled_last_pipeline_head = 0;
2434 2435 2436 2437
	tape->controlled_previous_pipeline_head = 0;
	tape->uncontrolled_previous_pipeline_head = 0;
	tape->controlled_pipeline_head_speed = 5000;
	tape->pipeline_head_speed = 5000;
L
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2438
	tape->uncontrolled_pipeline_head_speed = 0;
2439 2440 2441 2442
	tape->controlled_pipeline_head_time =
		tape->uncontrolled_pipeline_head_time = jiffies;
	tape->controlled_previous_head_time =
		tape->uncontrolled_previous_head_time = jiffies;
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}

2445
static int idetape_init_read(ide_drive_t *drive, int max_stages)
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2446 2447 2448 2449 2450
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *new_stage;
	struct request rq;
	int bytes_read;
2451
	u16 blocks = *(u16 *)&tape->caps[12];
L
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2452 2453

	/* Initialize read operation */
2454 2455
	if (tape->chrdev_dir != IDETAPE_DIR_READ) {
		if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
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2456 2457 2458 2459
			idetape_empty_write_pipeline(drive);
			idetape_flush_tape_buffers(drive);
		}
		if (tape->merge_stage || tape->merge_stage_size) {
2460 2461
			printk(KERN_ERR "ide-tape: merge_stage_size should be"
					 " 0 now\n");
L
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2462 2463
			tape->merge_stage_size = 0;
		}
2464 2465
		tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
		if (!tape->merge_stage)
L
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2466
			return -ENOMEM;
2467
		tape->chrdev_dir = IDETAPE_DIR_READ;
L
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2468 2469

		/*
2470 2471 2472 2473
		 * Issue a read 0 command to ensure that DSC handshake is
		 * switched from completion mode to buffer available mode.
		 * No point in issuing this if DSC overlap isn't supported, some
		 * drives (Seagate STT3401A) will return an error.
L
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2474 2475
		 */
		if (drive->dsc_overlap) {
2476 2477 2478
			bytes_read = idetape_queue_rw_tail(drive,
							REQ_IDETAPE_READ, 0,
							tape->merge_stage->bh);
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2479 2480 2481
			if (bytes_read < 0) {
				__idetape_kfree_stage(tape->merge_stage);
				tape->merge_stage = NULL;
2482
				tape->chrdev_dir = IDETAPE_DIR_NONE;
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2483 2484 2485 2486 2487 2488 2489
				return bytes_read;
			}
		}
	}
	if (tape->restart_speed_control_req)
		idetape_restart_speed_control(drive);
	idetape_init_rq(&rq, REQ_IDETAPE_READ);
2490
	rq.sector = tape->first_frame;
2491 2492
	rq.nr_sectors = blocks;
	rq.current_nr_sectors = blocks;
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2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509
	if (!test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags) &&
	    tape->nr_stages < max_stages) {
		new_stage = idetape_kmalloc_stage(tape);
		while (new_stage != NULL) {
			new_stage->rq = rq;
			idetape_add_stage_tail(drive, new_stage);
			if (tape->nr_stages >= max_stages)
				break;
			new_stage = idetape_kmalloc_stage(tape);
		}
	}
	if (!idetape_pipeline_active(tape)) {
		if (tape->nr_pending_stages >= 3 * max_stages / 4) {
			tape->measure_insert_time = 1;
			tape->insert_time = jiffies;
			tape->insert_size = 0;
			tape->insert_speed = 0;
2510
			idetape_plug_pipeline(drive);
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2511 2512 2513 2514 2515 2516
		}
	}
	return 0;
}

/*
2517 2518
 * Called from idetape_chrdev_read() to service a character device read request
 * and add read-ahead requests to our pipeline.
L
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2519
 */
2520
static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
L
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2521 2522 2523 2524 2525 2526
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;
	struct request *rq_ptr;
	int bytes_read;

2527
	debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
L
Linus Torvalds 已提交
2528

2529
	/* If we are at a filemark, return a read length of 0 */
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2530 2531 2532
	if (test_bit(IDETAPE_FILEMARK, &tape->flags))
		return 0;

2533
	/* Wait for the next block to reach the head of the pipeline. */
2534
	idetape_init_read(drive, tape->max_stages);
L
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2535 2536 2537
	if (tape->first_stage == NULL) {
		if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
			return 0;
2538 2539
		return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
					tape->merge_stage->bh);
L
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2540 2541 2542
	}
	idetape_wait_first_stage(drive);
	rq_ptr = &tape->first_stage->rq;
2543 2544
	bytes_read = tape->blk_size * (rq_ptr->nr_sectors -
					rq_ptr->current_nr_sectors);
2545 2546
	rq_ptr->nr_sectors = 0;
	rq_ptr->current_nr_sectors = 0;
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2547 2548 2549 2550 2551 2552 2553

	if (rq_ptr->errors == IDETAPE_ERROR_EOD)
		return 0;
	else {
		idetape_switch_buffers(tape, tape->first_stage);
		if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
			set_bit(IDETAPE_FILEMARK, &tape->flags);
2554
		spin_lock_irqsave(&tape->lock, flags);
L
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2555
		idetape_remove_stage_head(drive);
2556
		spin_unlock_irqrestore(&tape->lock, flags);
L
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2557
		tape->pipeline_head++;
2558
		idetape_calculate_speeds(drive);
L
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2559
	}
2560
	if (bytes_read > blocks * tape->blk_size) {
2561 2562
		printk(KERN_ERR "ide-tape: bug: trying to return more bytes"
				" than requested\n");
2563
		bytes_read = blocks * tape->blk_size;
L
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2564 2565 2566 2567
	}
	return (bytes_read);
}

2568
static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
L
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2569 2570 2571 2572
{
	idetape_tape_t *tape = drive->driver_data;
	struct idetape_bh *bh;
	int blocks;
2573

L
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2574 2575 2576 2577 2578 2579
	while (bcount) {
		unsigned int count;

		bh = tape->merge_stage->bh;
		count = min(tape->stage_size, bcount);
		bcount -= count;
2580
		blocks = count / tape->blk_size;
L
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2581
		while (count) {
2582 2583
			atomic_set(&bh->b_count,
				   min(count, (unsigned int)bh->b_size));
L
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2584 2585 2586 2587
			memset(bh->b_data, 0, atomic_read(&bh->b_count));
			count -= atomic_read(&bh->b_count);
			bh = bh->b_reqnext;
		}
2588 2589
		idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
				      tape->merge_stage->bh);
L
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2590 2591 2592
	}
}

2593
static int idetape_pipeline_size(ide_drive_t *drive)
L
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2594 2595 2596 2597 2598 2599 2600 2601 2602 2603
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *stage;
	struct request *rq;
	int size = 0;

	idetape_wait_for_pipeline(drive);
	stage = tape->first_stage;
	while (stage != NULL) {
		rq = &stage->rq;
2604 2605
		size += tape->blk_size * (rq->nr_sectors -
				rq->current_nr_sectors);
L
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2606
		if (rq->errors == IDETAPE_ERROR_FILEMARK)
2607
			size += tape->blk_size;
L
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2608 2609 2610 2611 2612 2613 2614
		stage = stage->next;
	}
	size += tape->merge_stage_size;
	return size;
}

/*
2615 2616 2617
 * Rewinds the tape to the Beginning Of the current Partition (BOP). We
 * currently support only one partition.
 */
2618
static int idetape_rewind_tape(ide_drive_t *drive)
L
Linus Torvalds 已提交
2619 2620 2621
{
	int retval;
	idetape_pc_t pc;
2622 2623 2624 2625 2626
	idetape_tape_t *tape;
	tape = drive->driver_data;

	debug_log(DBG_SENSE, "Enter %s\n", __func__);

L
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2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638
	idetape_create_rewind_cmd(drive, &pc);
	retval = idetape_queue_pc_tail(drive, &pc);
	if (retval)
		return retval;

	idetape_create_read_position_cmd(&pc);
	retval = idetape_queue_pc_tail(drive, &pc);
	if (retval)
		return retval;
	return 0;
}

2639
/* mtio.h compatible commands should be issued to the chrdev interface. */
2640 2641
static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
				unsigned long arg)
L
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2642 2643 2644 2645
{
	idetape_tape_t *tape = drive->driver_data;
	void __user *argp = (void __user *)arg;

2646 2647 2648 2649 2650 2651
	struct idetape_config {
		int dsc_rw_frequency;
		int dsc_media_access_frequency;
		int nr_stages;
	} config;

2652 2653
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

L
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2654
	switch (cmd) {
2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668
	case 0x0340:
		if (copy_from_user(&config, argp, sizeof(config)))
			return -EFAULT;
		tape->best_dsc_rw_freq = config.dsc_rw_frequency;
		tape->max_stages = config.nr_stages;
		break;
	case 0x0350:
		config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
		config.nr_stages = tape->max_stages;
		if (copy_to_user(argp, &config, sizeof(config)))
			return -EFAULT;
		break;
	default:
		return -EIO;
L
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2669 2670 2671 2672 2673
	}
	return 0;
}

/*
2674 2675 2676 2677 2678
 * The function below is now a bit more complicated than just passing the
 * command to the tape since we may have crossed some filemarks during our
 * pipelined read-ahead mode. As a minor side effect, the pipeline enables us to
 * support MTFSFM when the filemark is in our internal pipeline even if the tape
 * doesn't support spacing over filemarks in the reverse direction.
L
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2679
 */
2680 2681
static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
					int mt_count)
L
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2682 2683 2684 2685
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
	unsigned long flags;
2686
	int retval, count = 0;
2687
	int sprev = !!(tape->caps[4] & 0x20);
L
Linus Torvalds 已提交
2688 2689 2690 2691

	if (mt_count == 0)
		return 0;
	if (MTBSF == mt_op || MTBSFM == mt_op) {
2692
		if (!sprev)
L
Linus Torvalds 已提交
2693
			return -EIO;
2694
		mt_count = -mt_count;
L
Linus Torvalds 已提交
2695 2696
	}

2697
	if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2698
		/* its a read-ahead buffer, scan it for crossed filemarks. */
L
Linus Torvalds 已提交
2699 2700 2701 2702 2703 2704 2705 2706 2707
		tape->merge_stage_size = 0;
		if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
			++count;
		while (tape->first_stage != NULL) {
			if (count == mt_count) {
				if (mt_op == MTFSFM)
					set_bit(IDETAPE_FILEMARK, &tape->flags);
				return 0;
			}
2708
			spin_lock_irqsave(&tape->lock, flags);
L
Linus Torvalds 已提交
2709 2710
			if (tape->first_stage == tape->active_stage) {
				/*
2711 2712 2713 2714
				 * We have reached the active stage in the read
				 * pipeline. There is no point in allowing the
				 * drive to continue reading any farther, so we
				 * stop the pipeline.
L
Linus Torvalds 已提交
2715
				 *
2716 2717 2718 2719
				 * This section should be moved to a separate
				 * subroutine because similar operations are
				 * done in __idetape_discard_read_pipeline(),
				 * for example.
L
Linus Torvalds 已提交
2720 2721
				 */
				tape->next_stage = NULL;
2722
				spin_unlock_irqrestore(&tape->lock, flags);
L
Linus Torvalds 已提交
2723 2724 2725
				idetape_wait_first_stage(drive);
				tape->next_stage = tape->first_stage->next;
			} else
2726
				spin_unlock_irqrestore(&tape->lock, flags);
2727 2728
			if (tape->first_stage->rq.errors ==
					IDETAPE_ERROR_FILEMARK)
L
Linus Torvalds 已提交
2729 2730 2731 2732 2733 2734 2735
				++count;
			idetape_remove_stage_head(drive);
		}
		idetape_discard_read_pipeline(drive, 0);
	}

	/*
2736 2737
	 * The filemark was not found in our internal pipeline;	now we can issue
	 * the space command.
L
Linus Torvalds 已提交
2738 2739
	 */
	switch (mt_op) {
2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758
	case MTFSF:
	case MTBSF:
		idetape_create_space_cmd(&pc, mt_count - count,
					 IDETAPE_SPACE_OVER_FILEMARK);
		return idetape_queue_pc_tail(drive, &pc);
	case MTFSFM:
	case MTBSFM:
		if (!sprev)
			return -EIO;
		retval = idetape_space_over_filemarks(drive, MTFSF,
						      mt_count - count);
		if (retval)
			return retval;
		count = (MTBSFM == mt_op ? 1 : -1);
		return idetape_space_over_filemarks(drive, MTFSF, count);
	default:
		printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
				mt_op);
		return -EIO;
L
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2759 2760 2761 2762
	}
}

/*
2763
 * Our character device read / write functions.
L
Linus Torvalds 已提交
2764
 *
2765 2766 2767
 * The tape is optimized to maximize throughput when it is transferring an
 * integral number of the "continuous transfer limit", which is a parameter of
 * the specific tape (26kB on my particular tape, 32kB for Onstream).
L
Linus Torvalds 已提交
2768
 *
2769 2770 2771 2772 2773 2774 2775
 * As of version 1.3 of the driver, the character device provides an abstract
 * continuous view of the media - any mix of block sizes (even 1 byte) on the
 * same backup/restore procedure is supported. The driver will internally
 * convert the requests to the recommended transfer unit, so that an unmatch
 * between the user's block size to the recommended size will only result in a
 * (slightly) increased driver overhead, but will no longer hit performance.
 * This is not applicable to Onstream.
L
Linus Torvalds 已提交
2776
 */
2777 2778
static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
				   size_t count, loff_t *ppos)
L
Linus Torvalds 已提交
2779 2780 2781
{
	struct ide_tape_obj *tape = ide_tape_f(file);
	ide_drive_t *drive = tape->drive;
2782
	ssize_t bytes_read, temp, actually_read = 0, rc;
2783
	ssize_t ret = 0;
2784
	u16 ctl = *(u16 *)&tape->caps[12];
L
Linus Torvalds 已提交
2785

2786
	debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
L
Linus Torvalds 已提交
2787

2788
	if (tape->chrdev_dir != IDETAPE_DIR_READ) {
L
Linus Torvalds 已提交
2789
		if (test_bit(IDETAPE_DETECT_BS, &tape->flags))
2790 2791 2792
			if (count > tape->blk_size &&
			    (count % tape->blk_size) == 0)
				tape->user_bs_factor = count / tape->blk_size;
L
Linus Torvalds 已提交
2793
	}
2794 2795
	rc = idetape_init_read(drive, tape->max_stages);
	if (rc < 0)
L
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2796 2797 2798 2799
		return rc;
	if (count == 0)
		return (0);
	if (tape->merge_stage_size) {
2800 2801 2802 2803
		actually_read = min((unsigned int)(tape->merge_stage_size),
				    (unsigned int)count);
		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
					       actually_read))
2804
			ret = -EFAULT;
L
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2805 2806 2807 2808 2809
		buf += actually_read;
		tape->merge_stage_size -= actually_read;
		count -= actually_read;
	}
	while (count >= tape->stage_size) {
2810
		bytes_read = idetape_add_chrdev_read_request(drive, ctl);
L
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2811 2812
		if (bytes_read <= 0)
			goto finish;
2813 2814
		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
					       bytes_read))
2815
			ret = -EFAULT;
L
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2816 2817 2818 2819 2820
		buf += bytes_read;
		count -= bytes_read;
		actually_read += bytes_read;
	}
	if (count) {
2821
		bytes_read = idetape_add_chrdev_read_request(drive, ctl);
L
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2822 2823 2824
		if (bytes_read <= 0)
			goto finish;
		temp = min((unsigned long)count, (unsigned long)bytes_read);
2825 2826
		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
					       temp))
2827
			ret = -EFAULT;
L
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2828 2829 2830 2831 2832
		actually_read += temp;
		tape->merge_stage_size = bytes_read-temp;
	}
finish:
	if (!actually_read && test_bit(IDETAPE_FILEMARK, &tape->flags)) {
2833 2834
		debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);

L
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2835 2836 2837
		idetape_space_over_filemarks(drive, MTFSF, 1);
		return 0;
	}
2838

2839
	return ret ? ret : actually_read;
L
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2840 2841
}

2842
static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
L
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2843 2844 2845 2846
				     size_t count, loff_t *ppos)
{
	struct ide_tape_obj *tape = ide_tape_f(file);
	ide_drive_t *drive = tape->drive;
2847 2848
	ssize_t actually_written = 0;
	ssize_t ret = 0;
2849
	u16 ctl = *(u16 *)&tape->caps[12];
L
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2850 2851 2852 2853 2854

	/* The drive is write protected. */
	if (tape->write_prot)
		return -EACCES;

2855
	debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
L
Linus Torvalds 已提交
2856 2857

	/* Initialize write operation */
2858 2859
	if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
		if (tape->chrdev_dir == IDETAPE_DIR_READ)
L
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2860 2861 2862 2863 2864 2865
			idetape_discard_read_pipeline(drive, 1);
		if (tape->merge_stage || tape->merge_stage_size) {
			printk(KERN_ERR "ide-tape: merge_stage_size "
				"should be 0 now\n");
			tape->merge_stage_size = 0;
		}
2866 2867
		tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
		if (!tape->merge_stage)
L
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2868
			return -ENOMEM;
2869
		tape->chrdev_dir = IDETAPE_DIR_WRITE;
L
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2870 2871 2872
		idetape_init_merge_stage(tape);

		/*
2873 2874 2875 2876
		 * Issue a write 0 command to ensure that DSC handshake is
		 * switched from completion mode to buffer available mode. No
		 * point in issuing this if DSC overlap isn't supported, some
		 * drives (Seagate STT3401A) will return an error.
L
Linus Torvalds 已提交
2877 2878
		 */
		if (drive->dsc_overlap) {
2879 2880 2881
			ssize_t retval = idetape_queue_rw_tail(drive,
							REQ_IDETAPE_WRITE, 0,
							tape->merge_stage->bh);
L
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2882 2883 2884
			if (retval < 0) {
				__idetape_kfree_stage(tape->merge_stage);
				tape->merge_stage = NULL;
2885
				tape->chrdev_dir = IDETAPE_DIR_NONE;
L
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2886 2887 2888 2889 2890 2891 2892 2893 2894 2895
				return retval;
			}
		}
	}
	if (count == 0)
		return (0);
	if (tape->restart_speed_control_req)
		idetape_restart_speed_control(drive);
	if (tape->merge_stage_size) {
		if (tape->merge_stage_size >= tape->stage_size) {
2896
			printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
L
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2897 2898
			tape->merge_stage_size = 0;
		}
2899 2900 2901 2902 2903
		actually_written = min((unsigned int)
				(tape->stage_size - tape->merge_stage_size),
				(unsigned int)count);
		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
						 actually_written))
2904
				ret = -EFAULT;
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2905 2906 2907 2908 2909
		buf += actually_written;
		tape->merge_stage_size += actually_written;
		count -= actually_written;

		if (tape->merge_stage_size == tape->stage_size) {
2910
			ssize_t retval;
L
Linus Torvalds 已提交
2911
			tape->merge_stage_size = 0;
2912
			retval = idetape_add_chrdev_write_request(drive, ctl);
L
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2913 2914 2915 2916 2917
			if (retval <= 0)
				return (retval);
		}
	}
	while (count >= tape->stage_size) {
2918
		ssize_t retval;
2919 2920
		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
						 tape->stage_size))
2921
			ret = -EFAULT;
L
Linus Torvalds 已提交
2922 2923
		buf += tape->stage_size;
		count -= tape->stage_size;
2924
		retval = idetape_add_chrdev_write_request(drive, ctl);
L
Linus Torvalds 已提交
2925 2926 2927 2928 2929 2930
		actually_written += tape->stage_size;
		if (retval <= 0)
			return (retval);
	}
	if (count) {
		actually_written += count;
2931 2932
		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
						 count))
2933
			ret = -EFAULT;
L
Linus Torvalds 已提交
2934 2935
		tape->merge_stage_size += count;
	}
2936
	return ret ? ret : actually_written;
L
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2937 2938
}

2939
static int idetape_write_filemark(ide_drive_t *drive)
L
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2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952
{
	idetape_pc_t pc;

	/* Write a filemark */
	idetape_create_write_filemark_cmd(drive, &pc, 1);
	if (idetape_queue_pc_tail(drive, &pc)) {
		printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
		return -EIO;
	}
	return 0;
}

/*
2953 2954
 * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
 * requested.
L
Linus Torvalds 已提交
2955
 *
2956 2957 2958 2959
 * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
 * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
 * usually not supported (it is supported in the rare case in which we crossed
 * the filemark during our read-ahead pipelined operation mode).
L
Linus Torvalds 已提交
2960
 *
2961
 * The following commands are currently not supported:
L
Linus Torvalds 已提交
2962
 *
2963 2964
 * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
 * MT_ST_WRITE_THRESHOLD.
L
Linus Torvalds 已提交
2965
 */
2966
static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
L
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2967 2968 2969
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
2970
	int i, retval;
L
Linus Torvalds 已提交
2971

2972 2973
	debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
			mt_op, mt_count);
2974

2975
	/* Commands which need our pipelined read-ahead stages. */
L
Linus Torvalds 已提交
2976
	switch (mt_op) {
2977 2978 2979 2980 2981 2982 2983 2984 2985
	case MTFSF:
	case MTFSFM:
	case MTBSF:
	case MTBSFM:
		if (!mt_count)
			return 0;
		return idetape_space_over_filemarks(drive, mt_op, mt_count);
	default:
		break;
L
Linus Torvalds 已提交
2986
	}
2987

L
Linus Torvalds 已提交
2988
	switch (mt_op) {
2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045
	case MTWEOF:
		if (tape->write_prot)
			return -EACCES;
		idetape_discard_read_pipeline(drive, 1);
		for (i = 0; i < mt_count; i++) {
			retval = idetape_write_filemark(drive);
			if (retval)
				return retval;
		}
		return 0;
	case MTREW:
		idetape_discard_read_pipeline(drive, 0);
		if (idetape_rewind_tape(drive))
			return -EIO;
		return 0;
	case MTLOAD:
		idetape_discard_read_pipeline(drive, 0);
		idetape_create_load_unload_cmd(drive, &pc,
					       IDETAPE_LU_LOAD_MASK);
		return idetape_queue_pc_tail(drive, &pc);
	case MTUNLOAD:
	case MTOFFL:
		/*
		 * If door is locked, attempt to unlock before
		 * attempting to eject.
		 */
		if (tape->door_locked) {
			if (idetape_create_prevent_cmd(drive, &pc, 0))
				if (!idetape_queue_pc_tail(drive, &pc))
					tape->door_locked = DOOR_UNLOCKED;
		}
		idetape_discard_read_pipeline(drive, 0);
		idetape_create_load_unload_cmd(drive, &pc,
					      !IDETAPE_LU_LOAD_MASK);
		retval = idetape_queue_pc_tail(drive, &pc);
		if (!retval)
			clear_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
		return retval;
	case MTNOP:
		idetape_discard_read_pipeline(drive, 0);
		return idetape_flush_tape_buffers(drive);
	case MTRETEN:
		idetape_discard_read_pipeline(drive, 0);
		idetape_create_load_unload_cmd(drive, &pc,
			IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
		return idetape_queue_pc_tail(drive, &pc);
	case MTEOM:
		idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
		return idetape_queue_pc_tail(drive, &pc);
	case MTERASE:
		(void)idetape_rewind_tape(drive);
		idetape_create_erase_cmd(&pc);
		return idetape_queue_pc_tail(drive, &pc);
	case MTSETBLK:
		if (mt_count) {
			if (mt_count < tape->blk_size ||
			    mt_count % tape->blk_size)
L
Linus Torvalds 已提交
3046
				return -EIO;
3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062
			tape->user_bs_factor = mt_count / tape->blk_size;
			clear_bit(IDETAPE_DETECT_BS, &tape->flags);
		} else
			set_bit(IDETAPE_DETECT_BS, &tape->flags);
		return 0;
	case MTSEEK:
		idetape_discard_read_pipeline(drive, 0);
		return idetape_position_tape(drive,
			mt_count * tape->user_bs_factor, tape->partition, 0);
	case MTSETPART:
		idetape_discard_read_pipeline(drive, 0);
		return idetape_position_tape(drive, 0, mt_count, 0);
	case MTFSR:
	case MTBSR:
	case MTLOCK:
		if (!idetape_create_prevent_cmd(drive, &pc, 1))
L
Linus Torvalds 已提交
3063
			return 0;
3064 3065
		retval = idetape_queue_pc_tail(drive, &pc);
		if (retval)
L
Linus Torvalds 已提交
3066
			return retval;
3067 3068 3069 3070
		tape->door_locked = DOOR_EXPLICITLY_LOCKED;
		return 0;
	case MTUNLOCK:
		if (!idetape_create_prevent_cmd(drive, &pc, 0))
L
Linus Torvalds 已提交
3071
			return 0;
3072 3073 3074 3075 3076 3077 3078 3079 3080
		retval = idetape_queue_pc_tail(drive, &pc);
		if (retval)
			return retval;
		tape->door_locked = DOOR_UNLOCKED;
		return 0;
	default:
		printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
				mt_op);
		return -EIO;
L
Linus Torvalds 已提交
3081 3082 3083 3084
	}
}

/*
3085 3086 3087
 * Our character device ioctls. General mtio.h magnetic io commands are
 * supported here, and not in the corresponding block interface. Our own
 * ide-tape ioctls are supported on both interfaces.
L
Linus Torvalds 已提交
3088
 */
3089 3090
static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
				unsigned int cmd, unsigned long arg)
L
Linus Torvalds 已提交
3091 3092 3093 3094 3095 3096
{
	struct ide_tape_obj *tape = ide_tape_f(file);
	ide_drive_t *drive = tape->drive;
	struct mtop mtop;
	struct mtget mtget;
	struct mtpos mtpos;
3097
	int block_offset = 0, position = tape->first_frame;
L
Linus Torvalds 已提交
3098 3099
	void __user *argp = (void __user *)arg;

3100
	debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
L
Linus Torvalds 已提交
3101 3102

	tape->restart_speed_control_req = 1;
3103
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
L
Linus Torvalds 已提交
3104 3105 3106 3107
		idetape_empty_write_pipeline(drive);
		idetape_flush_tape_buffers(drive);
	}
	if (cmd == MTIOCGET || cmd == MTIOCPOS) {
3108 3109
		block_offset = idetape_pipeline_size(drive) /
			(tape->blk_size * tape->user_bs_factor);
3110 3111
		position = idetape_read_position(drive);
		if (position < 0)
L
Linus Torvalds 已提交
3112 3113 3114
			return -EIO;
	}
	switch (cmd) {
3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141
	case MTIOCTOP:
		if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
			return -EFAULT;
		return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
	case MTIOCGET:
		memset(&mtget, 0, sizeof(struct mtget));
		mtget.mt_type = MT_ISSCSI2;
		mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
		mtget.mt_dsreg =
			((tape->blk_size * tape->user_bs_factor)
			 << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;

		if (tape->drv_write_prot)
			mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);

		if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
			return -EFAULT;
		return 0;
	case MTIOCPOS:
		mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
		if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
			return -EFAULT;
		return 0;
	default:
		if (tape->chrdev_dir == IDETAPE_DIR_READ)
			idetape_discard_read_pipeline(drive, 1);
		return idetape_blkdev_ioctl(drive, cmd, arg);
L
Linus Torvalds 已提交
3142 3143 3144
	}
}

3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156
/*
 * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
 * block size with the reported value.
 */
static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;

	idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
	if (idetape_queue_pc_tail(drive, &pc)) {
		printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
3157
		if (tape->blk_size == 0) {
3158 3159
			printk(KERN_WARNING "ide-tape: Cannot deal with zero "
					    "block size, assuming 32k\n");
3160
			tape->blk_size = 32768;
3161 3162 3163
		}
		return;
	}
3164
	tape->blk_size = (pc.buffer[4 + 5] << 16) +
3165 3166 3167 3168
				(pc.buffer[4 + 6] << 8)  +
				 pc.buffer[4 + 7];
	tape->drv_write_prot = (pc.buffer[2] & 0x80) >> 7;
}
L
Linus Torvalds 已提交
3169

3170
static int idetape_chrdev_open(struct inode *inode, struct file *filp)
L
Linus Torvalds 已提交
3171 3172 3173 3174 3175 3176 3177
{
	unsigned int minor = iminor(inode), i = minor & ~0xc0;
	ide_drive_t *drive;
	idetape_tape_t *tape;
	idetape_pc_t pc;
	int retval;

3178 3179 3180 3181 3182 3183 3184 3185 3186
	if (i >= MAX_HWIFS * MAX_DRIVES)
		return -ENXIO;

	tape = ide_tape_chrdev_get(i);
	if (!tape)
		return -ENXIO;

	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);

L
Linus Torvalds 已提交
3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213
	/*
	 * We really want to do nonseekable_open(inode, filp); here, but some
	 * versions of tar incorrectly call lseek on tapes and bail out if that
	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
	 */
	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);

	drive = tape->drive;

	filp->private_data = tape;

	if (test_and_set_bit(IDETAPE_BUSY, &tape->flags)) {
		retval = -EBUSY;
		goto out_put_tape;
	}

	retval = idetape_wait_ready(drive, 60 * HZ);
	if (retval) {
		clear_bit(IDETAPE_BUSY, &tape->flags);
		printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
		goto out_put_tape;
	}

	idetape_read_position(drive);
	if (!test_bit(IDETAPE_ADDRESS_VALID, &tape->flags))
		(void)idetape_rewind_tape(drive);

3214
	if (tape->chrdev_dir != IDETAPE_DIR_READ)
L
Linus Torvalds 已提交
3215 3216 3217
		clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);

	/* Read block size and write protect status from drive. */
3218
	ide_tape_get_bsize_from_bdesc(drive);
L
Linus Torvalds 已提交
3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235

	/* Set write protect flag if device is opened as read-only. */
	if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
		tape->write_prot = 1;
	else
		tape->write_prot = tape->drv_write_prot;

	/* Make sure drive isn't write protected if user wants to write. */
	if (tape->write_prot) {
		if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
		    (filp->f_flags & O_ACCMODE) == O_RDWR) {
			clear_bit(IDETAPE_BUSY, &tape->flags);
			retval = -EROFS;
			goto out_put_tape;
		}
	}

3236
	/* Lock the tape drive door so user can't eject. */
3237
	if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
L
Linus Torvalds 已提交
3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253
		if (idetape_create_prevent_cmd(drive, &pc, 1)) {
			if (!idetape_queue_pc_tail(drive, &pc)) {
				if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
					tape->door_locked = DOOR_LOCKED;
			}
		}
	}
	idetape_restart_speed_control(drive);
	tape->restart_speed_control_req = 0;
	return 0;

out_put_tape:
	ide_tape_put(tape);
	return retval;
}

3254
static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
L
Linus Torvalds 已提交
3255 3256 3257 3258 3259 3260
{
	idetape_tape_t *tape = drive->driver_data;

	idetape_empty_write_pipeline(drive);
	tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
	if (tape->merge_stage != NULL) {
3261 3262
		idetape_pad_zeros(drive, tape->blk_size *
				(tape->user_bs_factor - 1));
L
Linus Torvalds 已提交
3263 3264 3265 3266 3267 3268 3269 3270
		__idetape_kfree_stage(tape->merge_stage);
		tape->merge_stage = NULL;
	}
	idetape_write_filemark(drive);
	idetape_flush_tape_buffers(drive);
	idetape_flush_tape_buffers(drive);
}

3271
static int idetape_chrdev_release(struct inode *inode, struct file *filp)
L
Linus Torvalds 已提交
3272 3273 3274 3275 3276 3277 3278 3279
{
	struct ide_tape_obj *tape = ide_tape_f(filp);
	ide_drive_t *drive = tape->drive;
	idetape_pc_t pc;
	unsigned int minor = iminor(inode);

	lock_kernel();
	tape = drive->driver_data;
3280 3281

	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
L
Linus Torvalds 已提交
3282

3283
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
L
Linus Torvalds 已提交
3284
		idetape_write_release(drive, minor);
3285
	if (tape->chrdev_dir == IDETAPE_DIR_READ) {
L
Linus Torvalds 已提交
3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296
		if (minor < 128)
			idetape_discard_read_pipeline(drive, 1);
		else
			idetape_wait_for_pipeline(drive);
	}
	if (tape->cache_stage != NULL) {
		__idetape_kfree_stage(tape->cache_stage);
		tape->cache_stage = NULL;
	}
	if (minor < 128 && test_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags))
		(void) idetape_rewind_tape(drive);
3297
	if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
L
Linus Torvalds 已提交
3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311
		if (tape->door_locked == DOOR_LOCKED) {
			if (idetape_create_prevent_cmd(drive, &pc, 0)) {
				if (!idetape_queue_pc_tail(drive, &pc))
					tape->door_locked = DOOR_UNLOCKED;
			}
		}
	}
	clear_bit(IDETAPE_BUSY, &tape->flags);
	ide_tape_put(tape);
	unlock_kernel();
	return 0;
}

/*
3312
 * check the contents of the ATAPI IDENTIFY command results. We return:
L
Linus Torvalds 已提交
3313
 *
3314 3315
 * 1 - If the tape can be supported by us, based on the information we have so
 * far.
L
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3316
 *
3317
 * 0 - If this tape driver is not currently supported by us.
L
Linus Torvalds 已提交
3318
 */
3319
static int idetape_identify_device(ide_drive_t *drive)
L
Linus Torvalds 已提交
3320
{
3321
	u8 gcw[2], protocol, device_type, removable, packet_size;
L
Linus Torvalds 已提交
3322 3323 3324 3325

	if (drive->id_read == 0)
		return 1;

3326
	*((unsigned short *) &gcw) = drive->id->config;
L
Linus Torvalds 已提交
3327

3328 3329 3330 3331
	protocol	=   (gcw[1] & 0xC0) >> 6;
	device_type	=    gcw[1] & 0x1F;
	removable	= !!(gcw[0] & 0x80);
	packet_size	=    gcw[0] & 0x3;
L
Linus Torvalds 已提交
3332

3333 3334
	/* Check that we can support this device */
	if (protocol != 2)
3335
		printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
3336 3337
				protocol);
	else if (device_type != 1)
3338
		printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
3339 3340
				"to tape\n", device_type);
	else if (!removable)
L
Linus Torvalds 已提交
3341
		printk(KERN_ERR "ide-tape: The removable flag is not set\n");
3342
	else if (packet_size != 0) {
3343 3344
		printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12"
				" bytes\n", packet_size);
L
Linus Torvalds 已提交
3345 3346 3347 3348 3349
	} else
		return 1;
	return 0;
}

3350
static void idetape_get_inquiry_results(ide_drive_t *drive)
L
Linus Torvalds 已提交
3351 3352 3353
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
3354
	char fw_rev[6], vendor_id[10], product_id[18];
3355

L
Linus Torvalds 已提交
3356 3357
	idetape_create_inquiry_cmd(&pc);
	if (idetape_queue_pc_tail(drive, &pc)) {
3358 3359
		printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
				tape->name);
L
Linus Torvalds 已提交
3360 3361
		return;
	}
3362 3363 3364 3365 3366 3367 3368 3369
	memcpy(vendor_id, &pc.buffer[8], 8);
	memcpy(product_id, &pc.buffer[16], 16);
	memcpy(fw_rev, &pc.buffer[32], 4);

	ide_fixstring(vendor_id, 10, 0);
	ide_fixstring(product_id, 18, 0);
	ide_fixstring(fw_rev, 6, 0);

3370
	printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
3371
			drive->name, tape->name, vendor_id, product_id, fw_rev);
L
Linus Torvalds 已提交
3372 3373 3374
}

/*
3375 3376
 * Ask the tape about its various parameters. In particular, we will adjust our
 * data transfer buffer	size to the recommended value as returned by the tape.
L
Linus Torvalds 已提交
3377
 */
3378
static void idetape_get_mode_sense_results(ide_drive_t *drive)
L
Linus Torvalds 已提交
3379 3380 3381
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
3382 3383
	u8 *caps;
	u8 speed, max_speed;
3384

L
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3385 3386
	idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
	if (idetape_queue_pc_tail(drive, &pc)) {
3387 3388
		printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
				" some default values\n");
3389
		tape->blk_size = 512;
3390 3391 3392
		put_unaligned(52,   (u16 *)&tape->caps[12]);
		put_unaligned(540,  (u16 *)&tape->caps[14]);
		put_unaligned(6*52, (u16 *)&tape->caps[16]);
L
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3393 3394
		return;
	}
3395 3396 3397 3398 3399
	caps = pc.buffer + 4 + pc.buffer[3];

	/* convert to host order and save for later use */
	speed = be16_to_cpu(*(u16 *)&caps[14]);
	max_speed = be16_to_cpu(*(u16 *)&caps[8]);
L
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3400

3401 3402 3403 3404
	put_unaligned(max_speed, (u16 *)&caps[8]);
	put_unaligned(be16_to_cpu(*(u16 *)&caps[12]), (u16 *)&caps[12]);
	put_unaligned(speed, (u16 *)&caps[14]);
	put_unaligned(be16_to_cpu(*(u16 *)&caps[16]), (u16 *)&caps[16]);
L
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3405

3406 3407 3408 3409
	if (!speed) {
		printk(KERN_INFO "ide-tape: %s: invalid tape speed "
				"(assuming 650KB/sec)\n", drive->name);
		put_unaligned(650, (u16 *)&caps[14]);
L
Linus Torvalds 已提交
3410
	}
3411 3412 3413 3414
	if (!max_speed) {
		printk(KERN_INFO "ide-tape: %s: invalid max_speed "
				"(assuming 650KB/sec)\n", drive->name);
		put_unaligned(650, (u16 *)&caps[8]);
L
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3415 3416
	}

3417 3418
	memcpy(&tape->caps, caps, 20);
	if (caps[7] & 0x02)
3419
		tape->blk_size = 512;
3420
	else if (caps[7] & 0x04)
3421
		tape->blk_size = 1024;
L
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3422 3423
}

3424
#ifdef CONFIG_IDE_PROC_FS
3425
static void idetape_add_settings(ide_drive_t *drive)
L
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3426 3427 3428
{
	idetape_tape_t *tape = drive->driver_data;

3429 3430
	ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
			1, 2, (u16 *)&tape->caps[16], NULL);
3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442
	ide_add_setting(drive, "pipeline_min", SETTING_RW, TYPE_INT, 1, 0xffff,
			tape->stage_size / 1024, 1, &tape->min_pipeline, NULL);
	ide_add_setting(drive, "pipeline", SETTING_RW, TYPE_INT, 1, 0xffff,
			tape->stage_size / 1024, 1, &tape->max_stages, NULL);
	ide_add_setting(drive, "pipeline_max", SETTING_RW, TYPE_INT, 1,	0xffff,
			tape->stage_size / 1024, 1, &tape->max_pipeline, NULL);
	ide_add_setting(drive, "pipeline_used",	SETTING_READ, TYPE_INT, 0,
			0xffff,	tape->stage_size / 1024, 1, &tape->nr_stages,
			NULL);
	ide_add_setting(drive, "pipeline_pending", SETTING_READ, TYPE_INT, 0,
			0xffff, tape->stage_size / 1024, 1,
			&tape->nr_pending_stages, NULL);
3443 3444
	ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
			1, 1, (u16 *)&tape->caps[14], NULL);
3445 3446 3447 3448 3449
	ide_add_setting(drive, "stage", SETTING_READ, TYPE_INT,	0, 0xffff, 1,
			1024, &tape->stage_size, NULL);
	ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
			IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
			NULL);
3450 3451 3452 3453 3454 3455 3456 3457 3458 3459
	ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,
			1, &drive->dsc_overlap, NULL);
	ide_add_setting(drive, "pipeline_head_speed_c", SETTING_READ, TYPE_INT,
			0, 0xffff, 1, 1, &tape->controlled_pipeline_head_speed,
			NULL);
	ide_add_setting(drive, "pipeline_head_speed_u", SETTING_READ, TYPE_INT,
			0, 0xffff, 1, 1,
			&tape->uncontrolled_pipeline_head_speed, NULL);
	ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,
			1, 1, &tape->avg_speed, NULL);
3460 3461
	ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
			1, &tape->debug_mask, NULL);
L
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3462
}
3463 3464 3465
#else
static inline void idetape_add_settings(ide_drive_t *drive) { ; }
#endif
L
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3466 3467

/*
3468
 * The function below is called to:
L
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3469
 *
3470 3471 3472 3473
 * 1. Initialize our various state variables.
 * 2. Ask the tape for its capabilities.
 * 3. Allocate a buffer which will be used for data transfer. The buffer size
 * is chosen based on the recommendation which we received in step 2.
L
Linus Torvalds 已提交
3474
 *
3475 3476
 * Note that at this point ide.c already assigned us an irq, so that we can
 * queue requests here and wait for their completion.
L
Linus Torvalds 已提交
3477
 */
3478
static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
L
Linus Torvalds 已提交
3479 3480 3481 3482
{
	unsigned long t1, tmid, tn, t;
	int speed;
	int stage_size;
3483
	u8 gcw[2];
L
Linus Torvalds 已提交
3484
	struct sysinfo si;
3485
	u16 *ctl = (u16 *)&tape->caps[12];
L
Linus Torvalds 已提交
3486

3487
	spin_lock_init(&tape->lock);
L
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3488
	drive->dsc_overlap = 1;
3489 3490 3491 3492
	if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
		printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
				 tape->name);
		drive->dsc_overlap = 0;
L
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3493 3494 3495 3496 3497 3498 3499 3500
	}
	/* Seagate Travan drives do not support DSC overlap. */
	if (strstr(drive->id->model, "Seagate STT3401"))
		drive->dsc_overlap = 0;
	tape->minor = minor;
	tape->name[0] = 'h';
	tape->name[1] = 't';
	tape->name[2] = '0' + minor;
3501
	tape->chrdev_dir = IDETAPE_DIR_NONE;
L
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3502 3503 3504 3505
	tape->pc = tape->pc_stack;
	tape->max_insert_speed = 10000;
	tape->speed_control = 1;
	*((unsigned short *) &gcw) = drive->id->config;
3506 3507 3508

	/* Command packet DRQ type */
	if (((gcw[0] & 0x60) >> 5) == 1)
L
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3509 3510
		set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);

3511 3512 3513
	tape->min_pipeline = 10;
	tape->max_pipeline = 10;
	tape->max_stages   = 10;
3514

L
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3515 3516
	idetape_get_inquiry_results(drive);
	idetape_get_mode_sense_results(drive);
3517
	ide_tape_get_bsize_from_bdesc(drive);
L
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3518
	tape->user_bs_factor = 1;
3519
	tape->stage_size = *ctl * tape->blk_size;
L
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3520 3521
	while (tape->stage_size > 0xffff) {
		printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
3522
		*ctl /= 2;
3523
		tape->stage_size = *ctl * tape->blk_size;
L
Linus Torvalds 已提交
3524 3525 3526 3527 3528 3529 3530 3531
	}
	stage_size = tape->stage_size;
	tape->pages_per_stage = stage_size / PAGE_SIZE;
	if (stage_size % PAGE_SIZE) {
		tape->pages_per_stage++;
		tape->excess_bh_size = PAGE_SIZE - stage_size % PAGE_SIZE;
	}

3532 3533
	/* Select the "best" DSC read/write polling freq and pipeline size. */
	speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
L
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3534 3535 3536

	tape->max_stages = speed * 1000 * 10 / tape->stage_size;

3537
	/* Limit memory use for pipeline to 10% of physical memory */
L
Linus Torvalds 已提交
3538
	si_meminfo(&si);
3539 3540 3541 3542 3543
	if (tape->max_stages * tape->stage_size >
			si.totalram * si.mem_unit / 10)
		tape->max_stages =
			si.totalram * si.mem_unit / (10 * tape->stage_size);

L
Linus Torvalds 已提交
3544 3545
	tape->max_stages   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
	tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
3546 3547 3548 3549 3550 3551 3552
	tape->max_pipeline =
		min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
	if (tape->max_stages == 0) {
		tape->max_stages   = 1;
		tape->min_pipeline = 1;
		tape->max_pipeline = 1;
	}
L
Linus Torvalds 已提交
3553 3554

	t1 = (tape->stage_size * HZ) / (speed * 1000);
3555
	tmid = (*(u16 *)&tape->caps[16] * 32 * HZ) / (speed * 125);
L
Linus Torvalds 已提交
3556 3557 3558 3559 3560 3561 3562 3563
	tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);

	if (tape->max_stages)
		t = tn;
	else
		t = t1;

	/*
3564 3565
	 * Ensure that the number we got makes sense; limit it within
	 * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
L
Linus Torvalds 已提交
3566
	 */
3567 3568 3569
	tape->best_dsc_rw_freq = max_t(unsigned long,
				min_t(unsigned long, t, IDETAPE_DSC_RW_MAX),
				IDETAPE_DSC_RW_MIN);
L
Linus Torvalds 已提交
3570 3571
	printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
		"%dkB pipeline, %lums tDSC%s\n",
3572 3573
		drive->name, tape->name, *(u16 *)&tape->caps[14],
		(*(u16 *)&tape->caps[16] * 512) / tape->stage_size,
L
Linus Torvalds 已提交
3574 3575
		tape->stage_size / 1024,
		tape->max_stages * tape->stage_size / 1024,
3576
		tape->best_dsc_rw_freq * 1000 / HZ,
L
Linus Torvalds 已提交
3577 3578 3579 3580 3581
		drive->using_dma ? ", DMA":"");

	idetape_add_settings(drive);
}

3582
static void ide_tape_remove(ide_drive_t *drive)
L
Linus Torvalds 已提交
3583 3584 3585
{
	idetape_tape_t *tape = drive->driver_data;

3586
	ide_proc_unregister_driver(drive, tape->driver);
L
Linus Torvalds 已提交
3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598

	ide_unregister_region(tape->disk);

	ide_tape_put(tape);
}

static void ide_tape_release(struct kref *kref)
{
	struct ide_tape_obj *tape = to_ide_tape(kref);
	ide_drive_t *drive = tape->drive;
	struct gendisk *g = tape->disk;

3599 3600
	BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);

L
Linus Torvalds 已提交
3601 3602
	drive->dsc_overlap = 0;
	drive->driver_data = NULL;
3603
	device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
3604 3605
	device_destroy(idetape_sysfs_class,
			MKDEV(IDETAPE_MAJOR, tape->minor + 128));
L
Linus Torvalds 已提交
3606 3607 3608 3609 3610 3611
	idetape_devs[tape->minor] = NULL;
	g->private_data = NULL;
	put_disk(g);
	kfree(tape);
}

3612
#ifdef CONFIG_IDE_PROC_FS
L
Linus Torvalds 已提交
3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631
static int proc_idetape_read_name
	(char *page, char **start, off_t off, int count, int *eof, void *data)
{
	ide_drive_t	*drive = (ide_drive_t *) data;
	idetape_tape_t	*tape = drive->driver_data;
	char		*out = page;
	int		len;

	len = sprintf(out, "%s\n", tape->name);
	PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
}

static ide_proc_entry_t idetape_proc[] = {
	{ "capacity",	S_IFREG|S_IRUGO,	proc_ide_read_capacity, NULL },
	{ "name",	S_IFREG|S_IRUGO,	proc_idetape_read_name,	NULL },
	{ NULL, 0, NULL, NULL }
};
#endif

3632
static int ide_tape_probe(ide_drive_t *);
L
Linus Torvalds 已提交
3633 3634

static ide_driver_t idetape_driver = {
3635
	.gen_driver = {
3636
		.owner		= THIS_MODULE,
3637 3638 3639
		.name		= "ide-tape",
		.bus		= &ide_bus_type,
	},
3640 3641
	.probe			= ide_tape_probe,
	.remove			= ide_tape_remove,
L
Linus Torvalds 已提交
3642 3643 3644 3645 3646 3647 3648
	.version		= IDETAPE_VERSION,
	.media			= ide_tape,
	.supports_dsc_overlap 	= 1,
	.do_request		= idetape_do_request,
	.end_request		= idetape_end_request,
	.error			= __ide_error,
	.abort			= __ide_abort,
3649
#ifdef CONFIG_IDE_PROC_FS
L
Linus Torvalds 已提交
3650
	.proc			= idetape_proc,
3651
#endif
L
Linus Torvalds 已提交
3652 3653
};

3654
/* Our character device supporting functions, passed to register_chrdev. */
3655
static const struct file_operations idetape_fops = {
L
Linus Torvalds 已提交
3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668
	.owner		= THIS_MODULE,
	.read		= idetape_chrdev_read,
	.write		= idetape_chrdev_write,
	.ioctl		= idetape_chrdev_ioctl,
	.open		= idetape_chrdev_open,
	.release	= idetape_chrdev_release,
};

static int idetape_open(struct inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct ide_tape_obj *tape;

3669 3670
	tape = ide_tape_get(disk);
	if (!tape)
L
Linus Torvalds 已提交
3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704
		return -ENXIO;

	return 0;
}

static int idetape_release(struct inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct ide_tape_obj *tape = ide_tape_g(disk);

	ide_tape_put(tape);

	return 0;
}

static int idetape_ioctl(struct inode *inode, struct file *file,
			unsigned int cmd, unsigned long arg)
{
	struct block_device *bdev = inode->i_bdev;
	struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
	ide_drive_t *drive = tape->drive;
	int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
	if (err == -EINVAL)
		err = idetape_blkdev_ioctl(drive, cmd, arg);
	return err;
}

static struct block_device_operations idetape_block_ops = {
	.owner		= THIS_MODULE,
	.open		= idetape_open,
	.release	= idetape_release,
	.ioctl		= idetape_ioctl,
};

3705
static int ide_tape_probe(ide_drive_t *drive)
L
Linus Torvalds 已提交
3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716
{
	idetape_tape_t *tape;
	struct gendisk *g;
	int minor;

	if (!strstr("ide-tape", drive->driver_req))
		goto failed;
	if (!drive->present)
		goto failed;
	if (drive->media != ide_tape)
		goto failed;
3717 3718 3719
	if (!idetape_identify_device(drive)) {
		printk(KERN_ERR "ide-tape: %s: not supported by this version of"
				" the driver\n", drive->name);
L
Linus Torvalds 已提交
3720 3721 3722
		goto failed;
	}
	if (drive->scsi) {
3723 3724
		printk(KERN_INFO "ide-tape: passing drive %s to ide-scsi"
				 " emulation.\n", drive->name);
L
Linus Torvalds 已提交
3725 3726
		goto failed;
	}
3727
	tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
L
Linus Torvalds 已提交
3728
	if (tape == NULL) {
3729 3730
		printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
				drive->name);
L
Linus Torvalds 已提交
3731 3732 3733 3734 3735 3736 3737 3738 3739
		goto failed;
	}

	g = alloc_disk(1 << PARTN_BITS);
	if (!g)
		goto out_free_tape;

	ide_init_disk(g, drive);

3740
	ide_proc_register_driver(drive, &idetape_driver);
L
Linus Torvalds 已提交
3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751

	kref_init(&tape->kref);

	tape->drive = drive;
	tape->driver = &idetape_driver;
	tape->disk = g;

	g->private_data = &tape->driver;

	drive->driver_data = tape;

3752
	mutex_lock(&idetape_ref_mutex);
L
Linus Torvalds 已提交
3753 3754 3755
	for (minor = 0; idetape_devs[minor]; minor++)
		;
	idetape_devs[minor] = tape;
3756
	mutex_unlock(&idetape_ref_mutex);
L
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3757 3758 3759

	idetape_setup(drive, tape, minor);

3760 3761 3762 3763
	device_create(idetape_sysfs_class, &drive->gendev,
		      MKDEV(IDETAPE_MAJOR, minor), "%s", tape->name);
	device_create(idetape_sysfs_class, &drive->gendev,
			MKDEV(IDETAPE_MAJOR, minor + 128), "n%s", tape->name);
3764

L
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3765 3766 3767 3768
	g->fops = &idetape_block_ops;
	ide_register_region(g);

	return 0;
3769

L
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3770 3771 3772
out_free_tape:
	kfree(tape);
failed:
3773
	return -ENODEV;
L
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3774 3775
}

3776
static void __exit idetape_exit(void)
L
Linus Torvalds 已提交
3777
{
3778
	driver_unregister(&idetape_driver.gen_driver);
3779
	class_destroy(idetape_sysfs_class);
L
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3780 3781 3782
	unregister_chrdev(IDETAPE_MAJOR, "ht");
}

3783
static int __init idetape_init(void)
L
Linus Torvalds 已提交
3784
{
3785 3786 3787 3788 3789 3790 3791 3792 3793
	int error = 1;
	idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
	if (IS_ERR(idetape_sysfs_class)) {
		idetape_sysfs_class = NULL;
		printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
		error = -EBUSY;
		goto out;
	}

L
Linus Torvalds 已提交
3794
	if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
3795 3796
		printk(KERN_ERR "ide-tape: Failed to register chrdev"
				" interface\n");
3797 3798
		error = -EBUSY;
		goto out_free_class;
L
Linus Torvalds 已提交
3799
	}
3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812

	error = driver_register(&idetape_driver.gen_driver);
	if (error)
		goto out_free_driver;

	return 0;

out_free_driver:
	driver_unregister(&idetape_driver.gen_driver);
out_free_class:
	class_destroy(idetape_sysfs_class);
out:
	return error;
L
Linus Torvalds 已提交
3813 3814
}

3815
MODULE_ALIAS("ide:*m-tape*");
L
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3816 3817 3818
module_init(idetape_init);
module_exit(idetape_exit);
MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
3819 3820
MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
MODULE_LICENSE("GPL");