ide-tape.c 114.0 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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 */

#define IDETAPE_VERSION "1.19"

#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>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#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 *****************************/


/*
 *	Pipelined mode parameters.
 *
 *	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:
 *
 *	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.
 *
 *	Setting the following parameter to 0 is illegal: the pipelined mode
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 *	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

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

/*
 *	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).
 */
#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)

/*
 *	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
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 *	interactive response, while using a high value might improve system
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 *	throughput.
 */
#define IDETAPE_FIFO_THRESHOLD 		2

/*
 *	DSC polling parameters.
 *
 *	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:
 *
 *	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 will service requests from
 *		the other device on the same interface meanwhile.
 *
 *	2.	After the successful initialization of a "media access
 *		packet command", which is a command which can take a long
 *		time to complete (it can be several seconds or 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 (one second), and if we don't receive DSC
 *		after IDETAPE_DSC_MA_THRESHOLD (5 minutes), we switch it to a
 *		lower frequency - IDETAPE_DSC_MA_SLOW (1 minute).
 *
 *	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.
 */
 
/*
 *	DSC timings.
 */
#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 ***********************/

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

/*
 *	For general magnetic tape device compatibility.
 */
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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;
};

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

/*
 *	A pipeline stage.
 */
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;

/*
 *	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 a variable
 *	of type idetape_tape_t, defined below.
 */
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;

	/*
	 *	DSC polling variables.
	 *
	 *	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.
	 */
	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 */
	unsigned long best_dsc_rw_frequency;
	/* The current polling frequency */
	unsigned long dsc_polling_frequency;
	/* Maximum waiting time */
	unsigned long dsc_timeout;

	/*
	 *	Read position information
	 */
	u8 partition;
	/* Current block */
	unsigned int first_frame_position;
	unsigned int last_frame_position;
	unsigned int blocks_in_buffer;

	/*
	 *	Last error information
	 */
	u8 sense_key, asc, ascq;

	/*
	 *	Character device operation
	 */
	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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	/*
	 *	Device information
	 */
	/* Usually 512 or 1024 bytes */
	unsigned short tape_block_size;
	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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	/*
	 *	Active data transfer request parameters.
	 *
	 *	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.
	 */
	/* Pointer to the request which is waiting in the device request queue */
	struct request *active_data_request;
	/* Data buffer size (chosen based on the tape's recommendation */
	int stage_size;
	idetape_stage_t *merge_stage;
	int merge_stage_size;
	struct idetape_bh *bh;
	char *b_data;
	int b_count;
	
	/*
	 *	Pipeline parameters.
	 *
	 *	To accomplish non-pipelined mode, we simply set the following
	 *	variables to zero (or NULL, where appropriate).
	 */
	/* 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 */
	spinlock_t spinlock;

	/*
	 * Measures average tape speed
	 */
	unsigned long avg_time;
	int avg_size;
	int avg_speed;

	char vendor_id[10];
	char product_id[18];
	char firmware_revision[6];
	int firmware_revision_num;

	/* 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;

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

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

	/*
	 * Measure tape still time, in milliseconds
	 */
	unsigned long tape_still_time_begin;
	int tape_still_time;

	/*
	 * Speed regulation negative feedback loop
	 */
	int speed_control;
	int pipeline_head_speed;
	int controlled_pipeline_head_speed;
	int uncontrolled_pipeline_head_speed;
	int controlled_last_pipeline_head;
	int uncontrolled_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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}

/*
 *	Tape door status
 */
#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

/*
 *	Some defines for the READ BUFFER command
 */
#define IDETAPE_RETRIEVE_FAULTY_BLOCK	6

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

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

/*
 *	Special requests for our block device strategy routine.
 *
 *	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.
 */

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),
	REQ_IDETAPE_READ_BUFFER	= (1 << 4),
};

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

/*
 *	The following is used to format the general configuration word of
 *	the ATAPI IDENTIFY DEVICE command.
 */
struct idetape_id_gcw {	
	unsigned packet_size		:2;	/* Packet Size */
	unsigned reserved234		:3;	/* Reserved */
	unsigned drq_type		:2;	/* Command packet DRQ type */
	unsigned removable		:1;	/* Removable media */
	unsigned device_type		:5;	/* Device type */
	unsigned reserved13		:1;	/* Reserved */
	unsigned protocol		:2;	/* Protocol type */
};

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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

/*
 *	The variables below are used for the character device interface.
 *	Additional state variables are defined in our ide_drive_t structure.
 */
static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES];

#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;
}

/*
 *      Function declarations
 *
 */
static int idetape_chrdev_release (struct inode *inode, struct file *filp);
static void idetape_write_release (ide_drive_t *drive, unsigned int minor);

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

static void idetape_input_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
{
	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;
		}
		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);
		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;
}

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

	while (bcount) {
		if (bh == NULL) {
			printk(KERN_ERR "ide-tape: bh == NULL in "
				"idetape_output_buffers\n");
			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) {
			pc->bh = bh = bh->b_reqnext;
			if (bh) {
				pc->b_data = bh->b_data;
				pc->b_count = atomic_read(&bh->b_count);
			}
		}
	}
}

static void idetape_update_buffers (idetape_pc_t *pc)
{
	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) {
			printk(KERN_ERR "ide-tape: bh == NULL in "
				"idetape_update_buffers\n");
			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.
 */
static idetape_pc_t *idetape_next_pc_storage (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;

702 703
	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)
		tape->pc_stack_index=0;
	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.
 */
 
/**************************************************************
 *                                                            *
 *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
 *  followed later on by kfree().   -ml                       *
 *                                                            *
 **************************************************************/
 
static struct request *idetape_next_rq_storage (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;

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

/*
 *	idetape_init_pc initializes a packet command.
 */
static void idetape_init_pc (idetape_pc_t *pc)
{
	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;
}

/*
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 * called on each failed packet command retry to analyze the request sense. We
 * currently do not utilize this information.
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 */
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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;

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	tape->sense_key = sense[2] & 0xF;
	tape->asc       = sense[12];
	tape->ascq      = sense[13];
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	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)) {
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		pc->actually_transferred = pc->request_transfer -
			tape->tape_block_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.
	 */
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	if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
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	    /* 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);
		}
	}
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	if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
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		pc->error = IDETAPE_ERROR_FILEMARK;
		set_bit(PC_ABORT, &pc->flags);
	}
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	if (pc->c[0] == WRITE_6) {
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		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) {
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		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;

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	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;
	tape->active_data_request = rq;
	tape->active_stage = stage;
	tape->next_stage = stage->next;
}

/*
 *	idetape_increase_max_pipeline_stages is a part of the feedback
 *	loop which tries to find the optimum number of stages. In the
 *	feedback loop, 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.
 */
static void idetape_increase_max_pipeline_stages (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	int increase = (tape->max_pipeline - tape->min_pipeline) / 10;
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	debug_log(DBG_PROCS, "Enter %s\n", __func__);
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	tape->max_stages += max(increase, 1);
	tape->max_stages = max(tape->max_stages, tape->min_pipeline);
	tape->max_stages = min(tape->max_stages, tape->max_pipeline);
}

/*
 *	idetape_kfree_stage calls kfree to completely free a stage, along with
 *	its related buffers.
 */
static void __idetape_kfree_stage (idetape_stage_t *stage)
{
	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);
}

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

/*
 *	idetape_remove_stage_head removes tape->first_stage from the pipeline.
 *	The caller should avoid race conditions.
 */
static void idetape_remove_stage_head (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *stage;
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	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)
			printk(KERN_ERR "ide-tape: bug: tape->next_stage != NULL\n");
		if (tape->nr_stages)
			printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 now\n");
	}
}

/*
 * 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;
}

/*
 *	idetape_end_request is used to finish servicing a request, and to
 *	insert a pending pipeline request into the main device queue.
 */
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) {
		case 0:	error = IDETAPE_ERROR_GENERAL; break;
		case 1: error = 0; break;
		default: error = uptodate;
	}
	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;
	}

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	spin_lock_irqsave(&tape->spinlock, flags);

	/* The request was a pipelined data transfer request */
	if (tape->active_data_request == rq) {
		active_stage = tape->active_stage;
		tape->active_stage = NULL;
		tape->active_data_request = NULL;
		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)
					idetape_abort_pipeline(drive, active_stage);
			}
		} 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) {
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			idetape_activate_next_stage(drive);
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			/*
			 * Insert the next request into the request queue.
			 */
			(void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
		} else if (!error) {
				idetape_increase_max_pipeline_stages(drive);
		}
	}
	ide_end_drive_cmd(drive, 0, 0);
//	blkdev_dequeue_request(rq);
//	drive->rq = NULL;
//	end_that_request_last(rq);

	if (remove_stage)
		idetape_remove_stage_head(drive);
	if (tape->active_data_request == NULL)
		clear_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
	spin_unlock_irqrestore(&tape->spinlock, flags);
	return 0;
}

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

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	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 {
		printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - Aborting request!\n");
		idetape_end_request(drive, 0, 0);
	}
	return ide_stopped;
}

static void idetape_create_request_sense_cmd (idetape_pc_t *pc)
{
	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));
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	rq->cmd_type = REQ_TYPE_SPECIAL;
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	rq->cmd[0] = cmd;
}

/*
 *	idetape_queue_pc_head generates 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.
 *
 *	idetape_queue_pc_head is called from the request handling part of
 *	the driver (the "bottom" part). Safe storage for the request should
 *	be allocated with idetape_next_pc_storage and idetape_next_rq_storage
 *	before calling idetape_queue_pc_head.
 *
 *	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.
 *
 *	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.
 */
static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
{
	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;

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	(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;
}

/*
 *	idetape_postpone_request postpones 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.
 */
static void idetape_postpone_request (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;

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

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

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

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/*
1112 1113 1114 1115 1116
 * 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
 * idetape_issue_packet_command.
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 */
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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;
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	xfer_func_t *xferfunc;
	idetape_io_buf *iobuf;
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	unsigned int temp;
#if SIMULATE_ERRORS
	static int error_sim_count = 0;
#endif
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	u16 bcount;
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	u8 stat, ireason;
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	debug_log(DBG_PROCS, "Enter %s - interrupt handler\n", __func__);
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	/* Clear the interrupt */
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	stat = ide_read_status(drive);
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	if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
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		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);
		}
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		debug_log(DBG_PROCS, "DMA finished\n");

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	}

	/* No more interrupts */
1170
	if ((stat & DRQ_STAT) == 0) {
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		debug_log(DBG_SENSE, "Packet command completed, %d bytes"
				" transferred\n", pc->actually_transferred);
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		clear_bit(PC_DMA_IN_PROGRESS, &pc->flags);
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		local_irq_enable();

#if SIMULATE_ERRORS
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		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);
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			stat |= ERR_STAT;
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		}
#endif
1185
		if ((stat & ERR_STAT) && pc->c[0] == REQUEST_SENSE)
1186 1187 1188
			stat &= ~ERR_STAT;
		if ((stat & ERR_STAT) || test_bit(PC_DMA_ERROR, &pc->flags)) {
			/* Error detected */
1189 1190
			debug_log(DBG_ERR, "%s: I/O error\n", tape->name);

1191
			if (pc->c[0] == REQUEST_SENSE) {
1192 1193
				printk(KERN_ERR "ide-tape: I/O error in request"
						" sense command\n");
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				return ide_do_reset(drive);
			}
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			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) &&
1204
		    (stat & SEEK_STAT) == 0) {
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			/* Media access command */
			tape->dsc_polling_start = jiffies;
			tape->dsc_polling_frequency = IDETAPE_DSC_MA_FAST;
			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");
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		ide_dma_off(drive);
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		return ide_do_reset(drive);
	}
	/* Get the number of bytes to transfer on this interrupt. */
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	bcount = (hwif->INB(IDE_BCOUNTH_REG) << 8) |
		  hwif->INB(IDE_BCOUNTL_REG);
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	ireason = hwif->INB(IDE_IREASON_REG);
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	if (ireason & CD) {
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		printk(KERN_ERR "ide-tape: CoD != 0 in %s\n", __func__);
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		return ide_do_reset(drive);
	}
1235
	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, ",
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				(ireason & IO) ? "Write" : "Read");
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		printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
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				(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 */
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		temp = pc->actually_transferred + bcount;
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		if (temp > pc->request_transfer) {
			if (temp > pc->buffer_size) {
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				printk(KERN_ERR "ide-tape: The tape wants to "
					"send us more data than expected "
					"- discarding data\n");
1251
				idetape_discard_data(drive, bcount);
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				ide_set_handler(drive, &idetape_pc_intr,
						IDETAPE_WAIT_CMD, NULL);
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				return ide_started;
			}
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			debug_log(DBG_SENSE, "The tape wants to send us more "
				"data than expected - allowing transfer\n");
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		}
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		iobuf = &idetape_input_buffers;
		xferfunc = hwif->atapi_input_bytes;
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	} else {
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		iobuf = &idetape_output_buffers;
		xferfunc = hwif->atapi_output_bytes;
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	}
1265 1266 1267 1268 1269 1270

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

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	/* Update the current position */
1272 1273
	pc->actually_transferred += bcount;
	pc->current_position += bcount;
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	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;
}

/*
 *	Packet Command Interface
 *
 *	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.
 *
 *	The handling will be done in three stages:
 *
 *	1.	idetape_issue_packet_command will send the packet command to the
 *		drive, and will set the interrupt handler to idetape_pc_intr.
 *
 *	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.
 *
 *	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.
 *
 *		ide.c will then give higher priority to requests which
 *		originate from the other device, until will change rq_status
 *		to RQ_ACTIVE.
 *
 *	4.	When the packet command is finished, it will be checked for errors.
 *
 *	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.
 *
 *	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.
 *
 */
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;
1332
	u8 ireason;
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	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");
		return startstop;
	}
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	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);
1343
		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");
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			ireason |= CD;
			ireason &= ~IO;
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		}
	}
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	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;
}

static ide_startstop_t idetape_issue_packet_command (ide_drive_t *drive, idetape_pc_t *pc)
{
	ide_hwif_t *hwif = drive->hwif;
	idetape_tape_t *tape = drive->driver_data;
	int dma_ok = 0;
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	u16 bcount;
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	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");
	}

1381
	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)) {
		/*
		 *	We will "abort" retrying a packet command in case
		 *	a legitimate error code was received (crossing a
		 *	filemark, or end of the media, for example).
		 */
		if (!test_bit(PC_ABORT, &pc->flags)) {
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			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);
	}
1410
	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 */
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	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");
1422
		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);

1427 1428 1429
	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)) {
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		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);
	}
}

/*
 *	General packet command callback function.
 */
static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
1448 1449

	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;
}

/*
 *	A mode sense command is used to "sense" tape parameters.
 */
static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
{
	idetape_init_pc(pc);
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	pc->c[0] = MODE_SENSE;
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	if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
		pc->c[1] = 8;	/* DBD = 1 - Don't return block descriptors */
	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;
	pc->c[4] = 255;		/* (We will just discard data in that case) */
	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;
}

1483
static void idetape_calculate_speeds(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;

	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;
		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))
		tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_last_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_pipeline_head_time);
	else if (time_after(jiffies, tape->controlled_previous_head_time))
		tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_previous_head_time);

	if (tape->nr_pending_stages < tape->max_stages /*- 1 */) {
		/* -1 for read mode error recovery */
		if (time_after(jiffies, tape->uncontrolled_previous_head_time + 10 * HZ)) {
			tape->uncontrolled_pipeline_head_time = jiffies;
			tape->uncontrolled_pipeline_head_speed = (tape->pipeline_head - tape->uncontrolled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->uncontrolled_previous_head_time);
		}
	} else {
		tape->uncontrolled_previous_head_time = jiffies;
		tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;
		if (time_after(jiffies, tape->uncontrolled_pipeline_head_time + 30 * HZ)) {
			tape->uncontrolled_pipeline_head_time = jiffies;
		}
	}
	tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed, tape->controlled_pipeline_head_speed);
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	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 +
				(1100 - tape->pipeline_head_speed) * 2 * (tape->nr_pending_stages - tape->max_stages / 2) / tape->max_stages;
		else
			tape->max_insert_speed = 500 +
				(tape->pipeline_head_speed - 500) * 2 * tape->nr_pending_stages / tape->max_stages;
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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;
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	tape->max_insert_speed = max(tape->max_insert_speed, 500);
}

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

1537 1538
	if (stat & SEEK_STAT) {
		if (stat & ERR_STAT) {
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			/* Error detected */
1540
			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);
}

static ide_startstop_t idetape_rw_callback (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	struct request *rq = HWGROUP(drive)->rq;
	int blocks = tape->pc->actually_transferred / tape->tape_block_size;

	tape->avg_size += blocks * tape->tape_block_size;
	tape->insert_size += blocks * tape->tape_block_size;
	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))
		tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
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	if (time_after_eq(jiffies, tape->avg_time + HZ)) {
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		tape->avg_speed = tape->avg_size * HZ / (jiffies - tape->avg_time) / 1024;
		tape->avg_size = 0;
		tape->avg_time = jiffies;
	}
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	debug_log(DBG_PROCS, "Enter %s\n", __func__);
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	tape->first_frame_position += blocks;
	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;
}

static void idetape_create_read_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
{
	idetape_init_pc(pc);
1593
	pc->c[0] = READ_6;
1594
	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
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	pc->c[1] = 1;
	pc->callback = &idetape_rw_callback;
	pc->bh = bh;
	atomic_set(&bh->b_count, 0);
	pc->buffer = NULL;
	pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
	if (pc->request_transfer == tape->stage_size)
		set_bit(PC_DMA_RECOMMENDED, &pc->flags);
}

static void idetape_create_read_buffer_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
{
	int size = 32768;
	struct idetape_bh *p = bh;

	idetape_init_pc(pc);
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	pc->c[0] = READ_BUFFER;
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	pc->c[1] = IDETAPE_RETRIEVE_FAULTY_BLOCK;
	pc->c[7] = size >> 8;
	pc->c[8] = size & 0xff;
	pc->callback = &idetape_pc_callback;
	pc->bh = bh;
	atomic_set(&bh->b_count, 0);
	pc->buffer = NULL;
	while (p) {
		atomic_set(&p->b_count, 0);
		p = p->b_reqnext;
	}
	pc->request_transfer = pc->buffer_size = size;
}

static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
{
	idetape_init_pc(pc);
1629
	pc->c[0] = WRITE_6;
1630
	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
L
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	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;
	pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
	if (pc->request_transfer == tape->stage_size)
		set_bit(PC_DMA_RECOMMENDED, &pc->flags);
}

/*
 * idetape_do_request is our request handling function.	
 */
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;
1652
	u8 stat;
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1654 1655
	debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
			" current_nr_sectors: %d\n",
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			rq->sector, rq->nr_sectors, rq->current_nr_sectors);

1658
	if (!blk_special_request(rq)) {
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		/*
		 * We do not support buffer cache originated requests.
		 */
		printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1663
			"request queue (%d)\n", drive->name, rq->cmd_type);
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		ide_end_request(drive, 0, 0);
		return ide_stopped;
	}

	/*
	 *	Retry a failed packet command
	 */
	if (tape->failed_pc != NULL &&
1672
	    tape->pc->c[0] == REQUEST_SENSE) {
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		return idetape_issue_packet_command(drive, tape->failed_pc);
	}
	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.
	 */
1689
	stat = ide_read_status(drive);
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	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 (tape->tape_still_time > 100 && tape->tape_still_time < 200)
		tape->measure_insert_time = 1;
	if (time_after(jiffies, tape->insert_time))
		tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
1703
	idetape_calculate_speeds(drive);
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	if (!test_and_clear_bit(IDETAPE_IGNORE_DSC, &tape->flags) &&
1705
	    (stat & SEEK_STAT) == 0) {
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		if (postponed_rq == NULL) {
			tape->dsc_polling_start = jiffies;
			tape->dsc_polling_frequency = tape->best_dsc_rw_frequency;
			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);
			}
1719
		} else if (time_after(jiffies, tape->dsc_polling_start + IDETAPE_DSC_MA_THRESHOLD))
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			tape->dsc_polling_frequency = IDETAPE_DSC_MA_SLOW;
		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);
		idetape_create_read_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
		goto out;
	}
	if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
		tape->buffer_head++;
		tape->postpone_cnt = 0;
		pc = idetape_next_pc_storage(drive);
		idetape_create_write_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
		goto out;
	}
	if (rq->cmd[0] & REQ_IDETAPE_READ_BUFFER) {
		tape->postpone_cnt = 0;
		pc = idetape_next_pc_storage(drive);
		idetape_create_read_buffer_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
		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:
	return idetape_issue_packet_command(drive, pc);
}

/*
 *	Pipeline related functions
 */
static inline int idetape_pipeline_active (idetape_tape_t *tape)
{
	int rc1, rc2;

	rc1 = test_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
	rc2 = (tape->active_data_request != NULL);
	return rc1;
}

/*
 *	idetape_kmalloc_stage 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.
 *
 *	Returns a pointer to the new allocated stage, or NULL if we
 *	can't (or don't want to) allocate a stage.
 *
 *	Pipeline stages are optional and are used to increase performance.
 *	If we can't allocate them, we'll manage without them.
 */
static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear)
{
	idetape_stage_t *stage;
	struct idetape_bh *prev_bh, *bh;
	int pages = tape->pages_per_stage;
	char *b_data = NULL;

1790
	if ((stage = kmalloc(sizeof (idetape_stage_t),GFP_KERNEL)) == NULL)
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		return NULL;
	stage->next = NULL;

1794
	bh = stage->bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
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	if (bh == NULL)
		goto abort;
	bh->b_reqnext = NULL;
	if ((bh->b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
		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) {
		if ((b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
			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;
1824
		if ((bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL)) == NULL) {
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			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;
}

static idetape_stage_t *idetape_kmalloc_stage (idetape_tape_t *tape)
{
	idetape_stage_t *cache_stage = tape->cache_stage;

1847
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
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	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);
}

1858
static int idetape_copy_stage_from_user (idetape_tape_t *tape, idetape_stage_t *stage, const char __user *buf, int n)
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{
	struct idetape_bh *bh = tape->bh;
	int count;
1862
	int ret = 0;
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	while (n) {
		if (bh == NULL) {
			printk(KERN_ERR "ide-tape: bh == NULL in "
				"idetape_copy_stage_from_user\n");
1868
			return 1;
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		}
		count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), (unsigned int)n);
1871 1872
		if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf, count))
			ret = 1;
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		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;
1883
	return ret;
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}

1886
static int idetape_copy_stage_to_user (idetape_tape_t *tape, char __user *buf, idetape_stage_t *stage, int n)
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{
	struct idetape_bh *bh = tape->bh;
	int count;
1890
	int ret = 0;
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	while (n) {
		if (bh == NULL) {
			printk(KERN_ERR "ide-tape: bh == NULL in "
				"idetape_copy_stage_to_user\n");
1896
			return 1;
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		}
		count = min(tape->b_count, n);
1899 1900
		if  (copy_to_user(buf, tape->b_data, count))
			ret = 1;
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		n -= count;
		tape->b_data += count;
		tape->b_count -= count;
		buf += count;
		if (!tape->b_count) {
			tape->bh = bh = bh->b_reqnext;
			if (bh) {
				tape->b_data = bh->b_data;
				tape->b_count = atomic_read(&bh->b_count);
			}
		}
	}
1913
	return ret;
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}

static void idetape_init_merge_stage (idetape_tape_t *tape)
{
	struct idetape_bh *bh = tape->merge_stage->bh;
	
	tape->bh = bh;
1921
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
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		atomic_set(&bh->b_count, 0);
	else {
		tape->b_data = bh->b_data;
		tape->b_count = atomic_read(&bh->b_count);
	}
}

static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage)
{
	struct idetape_bh *tmp;

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

/*
 *	idetape_add_stage_tail adds a new stage at the end of the pipeline.
 */
static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;
1946 1947 1948

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

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	spin_lock_irqsave(&tape->spinlock, flags);
	stage->next = NULL;
	if (tape->last_stage != NULL)
		tape->last_stage->next=stage;
	else
		tape->first_stage = tape->next_stage=stage;
	tape->last_stage = stage;
	if (tape->next_stage == NULL)
		tape->next_stage = tape->last_stage;
	tape->nr_stages++;
	tape->nr_pending_stages++;
	spin_unlock_irqrestore(&tape->spinlock, flags);
}

/*
 *	idetape_wait_for_request installs a completion in a pending request
 *	and sleeps until it is serviced.
 *
 *	The caller should ensure that the request will not be serviced
 *	before we install the completion (usually by disabling interrupts).
 */
static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
{
1972
	DECLARE_COMPLETION_ONSTACK(wait);
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	idetape_tape_t *tape = drive->driver_data;

1975
	if (rq == NULL || !blk_special_request(rq)) {
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		printk (KERN_ERR "ide-tape: bug: Trying to sleep on non-valid request\n");
		return;
	}
1979
	rq->end_io_data = &wait;
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	rq->end_io = blk_end_sync_rq;
	spin_unlock_irq(&tape->spinlock);
	wait_for_completion(&wait);
	/* The stage and its struct request have been deallocated */
	spin_lock_irq(&tape->spinlock);
}

1987
static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
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{
	idetape_tape_t *tape = drive->driver_data;
1990
	u8 *readpos = tape->pc->buffer;
1991 1992

	debug_log(DBG_PROCS, "Enter %s\n", __func__);
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	if (!tape->pc->error) {
1995 1996 1997 1998 1999 2000 2001 2002
		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");
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			clear_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
			idetape_end_request(drive, 0, 0);
		} else {
2006
			debug_log(DBG_SENSE, "Block Location - %u\n",
2007 2008 2009 2010 2011 2012 2013 2014
					be32_to_cpu(*(u32 *)&readpos[4]));

			tape->partition = readpos[1];
			tape->first_frame_position =
				be32_to_cpu(*(u32 *)&readpos[4]);
			tape->last_frame_position =
				be32_to_cpu(*(u32 *)&readpos[8]);
			tape->blocks_in_buffer = readpos[15];
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			set_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
			idetape_end_request(drive, 1, 0);
		}
	} else {
		idetape_end_request(drive, 0, 0);
	}
	return ide_stopped;
}

/*
 *	idetape_create_write_filemark_cmd will:
 *
 *		1.	Write a filemark if write_filemark=1.
 *		2.	Flush the device buffers without writing a filemark
 *			if write_filemark=0.
 *
 */
static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark)
{
	idetape_init_pc(pc);
2035
	pc->c[0] = WRITE_FILEMARKS;
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	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);
2044
	pc->c[0] = TEST_UNIT_READY;
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	pc->callback = &idetape_pc_callback;
}

/*
 *	idetape_queue_pc_tail is based on the following functions:
 *
 *	ide_do_drive_cmd from ide.c
 *	cdrom_queue_request and cdrom_queue_packet_command from ide-cd.c
 *
 *	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 in 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.
 *
 *	From the bottom part of the driver, we should allocate safe memory
 *	using idetape_next_pc_storage and idetape_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.
 */
static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
{
	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);
}

static void idetape_create_load_unload_cmd (ide_drive_t *drive, idetape_pc_t *pc,int cmd)
{
	idetape_init_pc(pc);
2082
	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;

	/*
	 * Wait for the tape to become ready
	 */
	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)
		    || (tape->asc == 0x3A)) {	/* no media */
			if (load_attempted)
				return -ENOMEDIUM;
			idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
			__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;
2114
		msleep(100);
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	}
	return -EIO;
}

static int idetape_queue_pc_tail (ide_drive_t *drive,idetape_pc_t *pc)
{
	return __idetape_queue_pc_tail(drive, pc);
}

static int idetape_flush_tape_buffers (ide_drive_t *drive)
{
	idetape_pc_t pc;
	int rc;

	idetape_create_write_filemark_cmd(drive, &pc, 0);
	if ((rc = idetape_queue_pc_tail(drive, &pc)))
		return rc;
	idetape_wait_ready(drive, 60 * 5 * HZ);
	return 0;
}

static void idetape_create_read_position_cmd (idetape_pc_t *pc)
{
	idetape_init_pc(pc);
2139
	pc->c[0] = READ_POSITION;
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	pc->request_transfer = 20;
	pc->callback = &idetape_read_position_callback;
}

static int idetape_read_position (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
	int position;

2150
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
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	idetape_create_read_position_cmd(&pc);
	if (idetape_queue_pc_tail(drive, &pc))
		return -1;
	position = tape->first_frame_position;
	return position;
}

static void idetape_create_locate_cmd (ide_drive_t *drive, idetape_pc_t *pc, unsigned int block, u8 partition, int skip)
{
	idetape_init_pc(pc);
2162
	pc->c[0] = POSITION_TO_ELEMENT;
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	pc->c[1] = 2;
2164
	put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
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	pc->c[8] = partition;
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

static int idetape_create_prevent_cmd (ide_drive_t *drive, idetape_pc_t *pc, int prevent)
{
	idetape_tape_t *tape = drive->driver_data;

2174 2175
	/* device supports locking according to capabilities page */
	if (!(tape->caps[6] & 0x01))
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		return 0;

	idetape_init_pc(pc);
2179
	pc->c[0] = ALLOW_MEDIUM_REMOVAL;
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	pc->c[4] = prevent;
	pc->callback = &idetape_pc_callback;
	return 1;
}

static int __idetape_discard_read_pipeline (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;
	int cnt;

2191
	if (tape->chrdev_dir != IDETAPE_DIR_READ)
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		return 0;

	/* Remove merge stage. */
	cnt = tape->merge_stage_size / tape->tape_block_size;
	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);
2206
	tape->chrdev_dir = IDETAPE_DIR_NONE;
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	/* Remove pipeline stages. */
	if (tape->first_stage == NULL)
		return 0;

	spin_lock_irqsave(&tape->spinlock, flags);
	tape->next_stage = NULL;
	if (idetape_pipeline_active(tape))
		idetape_wait_for_request(drive, tape->active_data_request);
	spin_unlock_irqrestore(&tape->spinlock, flags);

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

		cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors; 
		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;
}

/*
 *	idetape_position_tape positions 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.
 *	
 */
static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip)
{
	idetape_tape_t *tape = drive->driver_data;
	int retval;
	idetape_pc_t pc;

2246
	if (tape->chrdev_dir == IDETAPE_DIR_READ)
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		__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));
}

static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_position)
{
	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)) {
			printk(KERN_INFO "ide-tape: %s: position_tape failed in discard_pipeline()\n", tape->name);
			return;
		}
	}
}

/*
 * idetape_queue_rw_tail generates a read/write request for the block
 * device interface and wait for it to be serviced.
 */
static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh)
{
	idetape_tape_t *tape = drive->driver_data;
	struct request rq;

2284 2285
	debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);

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	if (idetape_pipeline_active(tape)) {
2287 2288
		printk(KERN_ERR "ide-tape: bug: the pipeline is active in %s\n",
				__func__);
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		return (0);
	}

	idetape_init_rq(&rq, cmd);
	rq.rq_disk = tape->disk;
	rq.special = (void *)bh;
	rq.sector = tape->first_frame_position;
	rq.nr_sectors = rq.current_nr_sectors = blocks;
	(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;
	return (tape->tape_block_size * (blocks-rq.current_nr_sectors));
}

/*
 *	idetape_insert_pipeline_into_queue is used to start servicing the
 *	pipeline stages, starting from tape->next_stage.
 */
static void idetape_insert_pipeline_into_queue (ide_drive_t *drive)
{
	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);
2321
		idetape_activate_next_stage(drive);
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		(void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
	}
}

static void idetape_create_inquiry_cmd (idetape_pc_t *pc)
{
	idetape_init_pc(pc);
2329
	pc->c[0] = INQUIRY;
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	pc->c[4] = pc->request_transfer = 254;
	pc->callback = &idetape_pc_callback;
}

static void idetape_create_rewind_cmd (ide_drive_t *drive, idetape_pc_t *pc)
{
	idetape_init_pc(pc);
2337
	pc->c[0] = REZERO_UNIT;
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	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

static void idetape_create_erase_cmd (idetape_pc_t *pc)
{
	idetape_init_pc(pc);
2345
	pc->c[0] = ERASE;
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	pc->c[1] = 1;
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

static void idetape_create_space_cmd (idetape_pc_t *pc,int count, u8 cmd)
{
	idetape_init_pc(pc);
2354
	pc->c[0] = SPACE;
2355
	put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
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	pc->c[1] = cmd;
	set_bit(PC_WAIT_FOR_DSC, &pc->flags);
	pc->callback = &idetape_pc_callback;
}

static void idetape_wait_first_stage (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;

	if (tape->first_stage == NULL)
		return;
	spin_lock_irqsave(&tape->spinlock, flags);
	if (tape->active_stage == tape->first_stage)
		idetape_wait_for_request(drive, tape->active_data_request);
	spin_unlock_irqrestore(&tape->spinlock, flags);
}

/*
 *	idetape_add_chrdev_write_request tries 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.
 *
 *	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.
 */
static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *new_stage;
	unsigned long flags;
	struct request *rq;

2392
	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
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     	/*
     	 *	Attempt to allocate a new stage.
	 *	Pay special attention to possible race conditions.
	 */
	while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
		spin_lock_irqsave(&tape->spinlock, flags);
		if (idetape_pipeline_active(tape)) {
			idetape_wait_for_request(drive, tape->active_data_request);
			spin_unlock_irqrestore(&tape->spinlock, flags);
		} else {
			spin_unlock_irqrestore(&tape->spinlock, flags);
			idetape_insert_pipeline_into_queue(drive);
			if (idetape_pipeline_active(tape))
				continue;
			/*
			 *	Linux is short on memory. Fallback to
			 *	non-pipelined operation mode for this request.
			 */
			return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
		}
	}
	rq = &new_stage->rq;
	idetape_init_rq(rq, REQ_IDETAPE_WRITE);
	/* Doesn't actually matter - We always assume sequential access */
	rq->sector = tape->first_frame_position;
	rq->nr_sectors = rq->current_nr_sectors = blocks;

	idetape_switch_buffers(tape, new_stage);
	idetape_add_stage_tail(drive, new_stage);
	tape->pipeline_head++;
2424
	idetape_calculate_speeds(drive);
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	/*
	 *	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 full enough
	 *	(90%) before starting to service requests, so that we will
	 *	be able to keep up with the higher speeds of the tape.
	 */
	if (!idetape_pipeline_active(tape)) {
		if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
		    tape->nr_stages >= tape->max_stages - tape->uncontrolled_pipeline_head_speed * 3 * 1024 / tape->tape_block_size) {
			tape->measure_insert_time = 1;
			tape->insert_time = jiffies;
			tape->insert_size = 0;
			tape->insert_speed = 0;
			idetape_insert_pipeline_into_queue(drive);
		}
	}
	if (test_and_clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
		/* Return a deferred error */
		return -EIO;
	return blocks;
}

/*
 *	idetape_wait_for_pipeline will wait until all pending pipeline
 *	requests are serviced. Typically called on device close.
 */
static void idetape_wait_for_pipeline (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;

	while (tape->next_stage || idetape_pipeline_active(tape)) {
		idetape_insert_pipeline_into_queue(drive);
		spin_lock_irqsave(&tape->spinlock, flags);
		if (idetape_pipeline_active(tape))
			idetape_wait_for_request(drive, tape->active_data_request);
		spin_unlock_irqrestore(&tape->spinlock, flags);
	}
}

static void idetape_empty_write_pipeline (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	int blocks, min;
	struct idetape_bh *bh;
2472

2473
	if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
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		printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline, but we are not writing.\n");
		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) {
		blocks = tape->merge_stage_size / tape->tape_block_size;
		if (tape->merge_stage_size % tape->tape_block_size) {
			unsigned int i;

			blocks++;
			i = tape->tape_block_size - tape->merge_stage_size % tape->tape_block_size;
			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) {

					printk(KERN_INFO "ide-tape: bug, bh NULL\n");
					break;
				}
				min = min(i, (unsigned int)(bh->b_size - atomic_read(&bh->b_count)));
				memset(bh->b_data + atomic_read(&bh->b_count), 0, min);
				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);
2516
	tape->chrdev_dir = IDETAPE_DIR_NONE;
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	/*
	 *	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).
	 */
	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);
	}
}

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

	tape->restart_speed_control_req = 0;
	tape->pipeline_head = 0;
	tape->controlled_last_pipeline_head = tape->uncontrolled_last_pipeline_head = 0;
	tape->controlled_previous_pipeline_head = tape->uncontrolled_previous_pipeline_head = 0;
	tape->pipeline_head_speed = tape->controlled_pipeline_head_speed = 5000;
	tape->uncontrolled_pipeline_head_speed = 0;
	tape->controlled_pipeline_head_time = tape->uncontrolled_pipeline_head_time = jiffies;
	tape->controlled_previous_head_time = tape->uncontrolled_previous_head_time = jiffies;
}

static int idetape_initiate_read (ide_drive_t *drive, int max_stages)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_stage_t *new_stage;
	struct request rq;
	int bytes_read;
2557
	u16 blocks = *(u16 *)&tape->caps[12];
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	/* Initialize read operation */
2560 2561
	if (tape->chrdev_dir != IDETAPE_DIR_READ) {
		if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
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			idetape_empty_write_pipeline(drive);
			idetape_flush_tape_buffers(drive);
		}
		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;
		}
		if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
			return -ENOMEM;
2571
		tape->chrdev_dir = IDETAPE_DIR_READ;
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		/*
		 *	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.
		 */
		if (drive->dsc_overlap) {
			bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh);
			if (bytes_read < 0) {
				__idetape_kfree_stage(tape->merge_stage);
				tape->merge_stage = NULL;
2585
				tape->chrdev_dir = IDETAPE_DIR_NONE;
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				return bytes_read;
			}
		}
	}
	if (tape->restart_speed_control_req)
		idetape_restart_speed_control(drive);
	idetape_init_rq(&rq, REQ_IDETAPE_READ);
	rq.sector = tape->first_frame_position;
	rq.nr_sectors = rq.current_nr_sectors = blocks;
	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;
			idetape_insert_pipeline_into_queue(drive);
		}
	}
	return 0;
}

/*
 *	idetape_add_chrdev_read_request is called from idetape_chrdev_read
 *	to service a character device read request and add read-ahead
 *	requests to our pipeline.
 */
static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
{
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;
	struct request *rq_ptr;
	int bytes_read;

2630
	debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
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	/*
	 * If we are at a filemark, return a read length of 0
	 */
	if (test_bit(IDETAPE_FILEMARK, &tape->flags))
		return 0;

	/*
	 * Wait for the next block to be available at the head
	 * of the pipeline
	 */
	idetape_initiate_read(drive, tape->max_stages);
	if (tape->first_stage == NULL) {
		if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
			return 0;
		return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, tape->merge_stage->bh);
	}
	idetape_wait_first_stage(drive);
	rq_ptr = &tape->first_stage->rq;
	bytes_read = tape->tape_block_size * (rq_ptr->nr_sectors - rq_ptr->current_nr_sectors);
	rq_ptr->nr_sectors = rq_ptr->current_nr_sectors = 0;


	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);
		spin_lock_irqsave(&tape->spinlock, flags);
		idetape_remove_stage_head(drive);
		spin_unlock_irqrestore(&tape->spinlock, flags);
		tape->pipeline_head++;
2664
		idetape_calculate_speeds(drive);
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	}
	if (bytes_read > blocks * tape->tape_block_size) {
		printk(KERN_ERR "ide-tape: bug: trying to return more bytes than requested\n");
		bytes_read = blocks * tape->tape_block_size;
	}
	return (bytes_read);
}

static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
{
	idetape_tape_t *tape = drive->driver_data;
	struct idetape_bh *bh;
	int blocks;
	
	while (bcount) {
		unsigned int count;

		bh = tape->merge_stage->bh;
		count = min(tape->stage_size, bcount);
		bcount -= count;
		blocks = count / tape->tape_block_size;
		while (count) {
			atomic_set(&bh->b_count, min(count, (unsigned int)bh->b_size));
			memset(bh->b_data, 0, atomic_read(&bh->b_count));
			count -= atomic_read(&bh->b_count);
			bh = bh->b_reqnext;
		}
		idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
	}
}

static int idetape_pipeline_size (ide_drive_t *drive)
{
	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;
		size += tape->tape_block_size * (rq->nr_sectors-rq->current_nr_sectors);
		if (rq->errors == IDETAPE_ERROR_FILEMARK)
			size += tape->tape_block_size;
		stage = stage->next;
	}
	size += tape->merge_stage_size;
	return size;
}

/*
 *	Rewinds the tape to the Beginning Of the current Partition (BOP).
 *
 *	We currently support only one partition.
 */ 
static int idetape_rewind_tape (ide_drive_t *drive)
{
	int retval;
	idetape_pc_t pc;
2725 2726 2727 2728 2729
	idetape_tape_t *tape;
	tape = drive->driver_data;

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

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	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;
}

/*
 *	Our special ide-tape ioctl's.
 *
 *	Currently there aren't any ioctl's.
 *	mtio.h compatible commands should be issued to the character device
 *	interface.
 */
static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg)
{
	idetape_tape_t *tape = drive->driver_data;
	void __user *argp = (void __user *)arg;

2754 2755 2756 2757 2758 2759
	struct idetape_config {
		int dsc_rw_frequency;
		int dsc_media_access_frequency;
		int nr_stages;
	} config;

2760 2761
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

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	switch (cmd) {
		case 0x0340:
2764
			if (copy_from_user(&config, argp, sizeof(config)))
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				return -EFAULT;
			tape->best_dsc_rw_frequency = config.dsc_rw_frequency;
			tape->max_stages = config.nr_stages;
			break;
		case 0x0350:
			config.dsc_rw_frequency = (int) tape->best_dsc_rw_frequency;
			config.nr_stages = tape->max_stages; 
2772
			if (copy_to_user(argp, &config, sizeof(config)))
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				return -EFAULT;
			break;
		default:
			return -EIO;
	}
	return 0;
}

/*
 *	idetape_space_over_filemarks 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.
 */
static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
	unsigned long flags;
	int retval,count=0;
2796
	int sprev = !!(tape->caps[4] & 0x20);
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	if (mt_count == 0)
		return 0;
	if (MTBSF == mt_op || MTBSFM == mt_op) {
2801
		if (!sprev)
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			return -EIO;
		mt_count = - mt_count;
	}

2806
	if (tape->chrdev_dir == IDETAPE_DIR_READ) {
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		/*
		 *	We have a read-ahead buffer. Scan it for crossed
		 *	filemarks.
		 */
		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;
			}
			spin_lock_irqsave(&tape->spinlock, flags);
			if (tape->first_stage == tape->active_stage) {
				/*
				 *	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.
				 *
				 *	This section should be moved to a separate subroutine,
				 *	because a similar function is performed in
				 *	__idetape_discard_read_pipeline(), for example.
				 */
				tape->next_stage = NULL;
				spin_unlock_irqrestore(&tape->spinlock, flags);
				idetape_wait_first_stage(drive);
				tape->next_stage = tape->first_stage->next;
			} else
				spin_unlock_irqrestore(&tape->spinlock, flags);
			if (tape->first_stage->rq.errors == IDETAPE_ERROR_FILEMARK)
				++count;
			idetape_remove_stage_head(drive);
		}
		idetape_discard_read_pipeline(drive, 0);
	}

	/*
	 *	The filemark was not found in our internal pipeline.
	 *	Now we can issue the space command.
	 */
	switch (mt_op) {
		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:
2855
			if (!sprev)
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				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);
	}
}


/*
 *	Our character device read / write functions.
 *
 *	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 (26 KB on my particular tape).
 *      (32 kB for Onstream)
 *
 *	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.
 */
static ssize_t idetape_chrdev_read (struct file *file, char __user *buf,
				    size_t count, loff_t *ppos)
{
	struct ide_tape_obj *tape = ide_tape_f(file);
	ide_drive_t *drive = tape->drive;
	ssize_t bytes_read,temp, actually_read = 0, rc;
2891
	ssize_t ret = 0;
2892
	u16 ctl = *(u16 *)&tape->caps[12];
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2894
	debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
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2895

2896
	if (tape->chrdev_dir != IDETAPE_DIR_READ) {
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		if (test_bit(IDETAPE_DETECT_BS, &tape->flags))
			if (count > tape->tape_block_size &&
			    (count % tape->tape_block_size) == 0)
				tape->user_bs_factor = count / tape->tape_block_size;
	}
	if ((rc = idetape_initiate_read(drive, tape->max_stages)) < 0)
		return rc;
	if (count == 0)
		return (0);
	if (tape->merge_stage_size) {
		actually_read = min((unsigned int)(tape->merge_stage_size), (unsigned int)count);
2908 2909
		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, actually_read))
			ret = -EFAULT;
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		buf += actually_read;
		tape->merge_stage_size -= actually_read;
		count -= actually_read;
	}
	while (count >= tape->stage_size) {
2915
		bytes_read = idetape_add_chrdev_read_request(drive, ctl);
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		if (bytes_read <= 0)
			goto finish;
2918 2919
		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, bytes_read))
			ret = -EFAULT;
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		buf += bytes_read;
		count -= bytes_read;
		actually_read += bytes_read;
	}
	if (count) {
2925
		bytes_read = idetape_add_chrdev_read_request(drive, ctl);
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		if (bytes_read <= 0)
			goto finish;
		temp = min((unsigned long)count, (unsigned long)bytes_read);
2929 2930
		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, temp))
			ret = -EFAULT;
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		actually_read += temp;
		tape->merge_stage_size = bytes_read-temp;
	}
finish:
	if (!actually_read && test_bit(IDETAPE_FILEMARK, &tape->flags)) {
2936 2937
		debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);

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		idetape_space_over_filemarks(drive, MTFSF, 1);
		return 0;
	}
2941 2942

	return (ret) ? ret : actually_read;
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}

static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
				     size_t count, loff_t *ppos)
{
	struct ide_tape_obj *tape = ide_tape_f(file);
	ide_drive_t *drive = tape->drive;
2950 2951
	ssize_t actually_written = 0;
	ssize_t ret = 0;
2952
	u16 ctl = *(u16 *)&tape->caps[12];
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	/* The drive is write protected. */
	if (tape->write_prot)
		return -EACCES;

2958
	debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
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	/* Initialize write operation */
2961 2962
	if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
		if (tape->chrdev_dir == IDETAPE_DIR_READ)
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			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;
		}
		if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
			return -ENOMEM;
2971
		tape->chrdev_dir = IDETAPE_DIR_WRITE;
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		idetape_init_merge_stage(tape);

		/*
		 *	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.
		 */
		if (drive->dsc_overlap) {
2982
			ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
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			if (retval < 0) {
				__idetape_kfree_stage(tape->merge_stage);
				tape->merge_stage = NULL;
2986
				tape->chrdev_dir = IDETAPE_DIR_NONE;
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				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) {
			printk(KERN_ERR "ide-tape: bug: merge buffer too big\n");
			tape->merge_stage_size = 0;
		}
		actually_written = min((unsigned int)(tape->stage_size - tape->merge_stage_size), (unsigned int)count);
3001 3002
		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, actually_written))
				ret = -EFAULT;
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		buf += actually_written;
		tape->merge_stage_size += actually_written;
		count -= actually_written;

		if (tape->merge_stage_size == tape->stage_size) {
3008
			ssize_t retval;
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			tape->merge_stage_size = 0;
3010
			retval = idetape_add_chrdev_write_request(drive, ctl);
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			if (retval <= 0)
				return (retval);
		}
	}
	while (count >= tape->stage_size) {
3016 3017 3018
		ssize_t retval;
		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, tape->stage_size))
			ret = -EFAULT;
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		buf += tape->stage_size;
		count -= tape->stage_size;
3021
		retval = idetape_add_chrdev_write_request(drive, ctl);
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		actually_written += tape->stage_size;
		if (retval <= 0)
			return (retval);
	}
	if (count) {
		actually_written += count;
3028 3029
		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, count))
			ret = -EFAULT;
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		tape->merge_stage_size += count;
	}
3032
	return (ret) ? ret : actually_written;
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}

static int idetape_write_filemark (ide_drive_t *drive)
{
	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;
}

/*
3049 3050
 * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
 * requested.
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 *
3052 3053 3054 3055
 * 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).
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3056
 *
3057
 * The following commands are currently not supported:
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 *
3059 3060
 * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
 * MT_ST_WRITE_THRESHOLD.
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 */
3062
static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
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{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
	int i,retval;

3068 3069
	debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
			mt_op, mt_count);
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	/*
	 *	Commands which need our pipelined read-ahead stages.
	 */
	switch (mt_op) {
		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;
	}
	switch (mt_op) {
		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->tape_block_size || mt_count % tape->tape_block_size)
					return -EIO;
				tape->user_bs_factor = mt_count / tape->tape_block_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))
				return 0;
			retval = idetape_queue_pc_tail(drive, &pc);
			if (retval) return retval;
			tape->door_locked = DOOR_EXPLICITLY_LOCKED;
			return 0;
		case MTUNLOCK:
			if (!idetape_create_prevent_cmd(drive, &pc, 0))
				return 0;
			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);
	}
}

/*
3174 3175 3176
 * 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
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3177
 */
3178 3179
static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
				unsigned int cmd, unsigned long arg)
L
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3180 3181 3182 3183 3184 3185 3186 3187 3188
{
	struct ide_tape_obj *tape = ide_tape_f(file);
	ide_drive_t *drive = tape->drive;
	struct mtop mtop;
	struct mtget mtget;
	struct mtpos mtpos;
	int block_offset = 0, position = tape->first_frame_position;
	void __user *argp = (void __user *)arg;

3189
	debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
L
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3190 3191

	tape->restart_speed_control_req = 1;
3192
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
L
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3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222
		idetape_empty_write_pipeline(drive);
		idetape_flush_tape_buffers(drive);
	}
	if (cmd == MTIOCGET || cmd == MTIOCPOS) {
		block_offset = idetape_pipeline_size(drive) / (tape->tape_block_size * tape->user_bs_factor);
		if ((position = idetape_read_position(drive)) < 0)
			return -EIO;
	}
	switch (cmd) {
		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->tape_block_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:
3223
			if (tape->chrdev_dir == IDETAPE_DIR_READ)
L
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3224 3225 3226 3227 3228
				idetape_discard_read_pipeline(drive, 1);
			return idetape_blkdev_ioctl(drive, cmd, arg);
	}
}

3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252
/*
 * 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");
		if (tape->tape_block_size == 0) {
			printk(KERN_WARNING "ide-tape: Cannot deal with zero "
					    "block size, assuming 32k\n");
			tape->tape_block_size = 32768;
		}
		return;
	}
	tape->tape_block_size = (pc.buffer[4 + 5] << 16) +
				(pc.buffer[4 + 6] << 8)  +
				 pc.buffer[4 + 7];
	tape->drv_write_prot = (pc.buffer[2] & 0x80) >> 7;
}
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3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264

/*
 *	Our character device open function.
 */
static int idetape_chrdev_open (struct inode *inode, struct file *filp)
{
	unsigned int minor = iminor(inode), i = minor & ~0xc0;
	ide_drive_t *drive;
	idetape_tape_t *tape;
	idetape_pc_t pc;
	int retval;

3265 3266 3267 3268 3269 3270 3271 3272 3273
	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__);

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3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300
	/*
	 * 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);

3301
	if (tape->chrdev_dir != IDETAPE_DIR_READ)
L
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3302 3303 3304
		clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);

	/* Read block size and write protect status from drive. */
3305
	ide_tape_get_bsize_from_bdesc(drive);
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3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325

	/* 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;
		}
	}

	/*
	 * Lock the tape drive door so user can't eject.
	 */
3326
	if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
L
Linus Torvalds 已提交
3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370
		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;
}

static void idetape_write_release (ide_drive_t *drive, unsigned int minor)
{
	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) {
		idetape_pad_zeros(drive, tape->tape_block_size * (tape->user_bs_factor - 1));
		__idetape_kfree_stage(tape->merge_stage);
		tape->merge_stage = NULL;
	}
	idetape_write_filemark(drive);
	idetape_flush_tape_buffers(drive);
	idetape_flush_tape_buffers(drive);
}

/*
 *	Our character device release function.
 */
static int idetape_chrdev_release (struct inode *inode, struct file *filp)
{
	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;
3371 3372

	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
L
Linus Torvalds 已提交
3373

3374
	if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
L
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3375
		idetape_write_release(drive, minor);
3376
	if (tape->chrdev_dir == IDETAPE_DIR_READ) {
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3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387
		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);
3388
	if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
L
Linus Torvalds 已提交
3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422
		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;
}

/*
 *	idetape_identify_device is called to check the contents of the
 *	ATAPI IDENTIFY command results. We return:
 *
 *	1	If the tape can be supported by us, based on the information
 *		we have so far.
 *
 *	0 	If this tape driver is not currently supported by us.
 */
static int idetape_identify_device (ide_drive_t *drive)
{
	struct idetape_id_gcw gcw;
	struct hd_driveid *id = drive->id;

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

	*((unsigned short *) &gcw) = id->config;

	/* Check that we can support this device */

3423 3424 3425
	if (gcw.protocol != 2)
		printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
				gcw.protocol);
L
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3426
	else if (gcw.device_type != 1)
3427 3428
		printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
				"to tape\n", gcw.device_type);
L
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3429 3430 3431
	else if (!gcw.removable)
		printk(KERN_ERR "ide-tape: The removable flag is not set\n");
	else if (gcw.packet_size != 0) {
3432 3433
		printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12 "
				"bytes long\n", gcw.packet_size);
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3434 3435 3436 3437 3438
	} else
		return 1;
	return 0;
}

3439
static void idetape_get_inquiry_results(ide_drive_t *drive)
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3440 3441 3442 3443
{
	char *r;
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
3444

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3445 3446
	idetape_create_inquiry_cmd(&pc);
	if (idetape_queue_pc_tail(drive, &pc)) {
3447 3448
		printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
				tape->name);
L
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3449 3450
		return;
	}
3451 3452 3453 3454
	memcpy(tape->vendor_id, &pc.buffer[8], 8);
	memcpy(tape->product_id, &pc.buffer[16], 16);
	memcpy(tape->firmware_revision, &pc.buffer[32], 4);

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3455 3456 3457 3458 3459
	ide_fixstring(tape->vendor_id, 10, 0);
	ide_fixstring(tape->product_id, 18, 0);
	ide_fixstring(tape->firmware_revision, 6, 0);
	r = tape->firmware_revision;
	if (*(r + 1) == '.')
3460 3461 3462 3463 3464
		tape->firmware_revision_num = (*r - '0') * 100 +
			(*(r + 2) - '0') * 10 +	*(r + 3) - '0';
	printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
			drive->name, tape->name, tape->vendor_id,
			tape->product_id, tape->firmware_revision);
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3465 3466 3467
}

/*
3468 3469
 * 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
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3470 3471 3472 3473 3474
 */
static void idetape_get_mode_sense_results (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
	idetape_pc_t pc;
3475 3476
	u8 *caps;
	u8 speed, max_speed;
3477

L
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3478 3479
	idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
	if (idetape_queue_pc_tail(drive, &pc)) {
3480 3481
		printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
				" some default values\n");
L
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3482
		tape->tape_block_size = 512;
3483 3484 3485
		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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3486 3487
		return;
	}
3488 3489 3490 3491 3492
	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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3493

3494 3495 3496 3497
	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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3498

3499 3500 3501 3502
	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
3503
	}
3504 3505 3506 3507
	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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3508 3509
	}

3510 3511
	memcpy(&tape->caps, caps, 20);
	if (caps[7] & 0x02)
L
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3512
		tape->tape_block_size = 512;
3513
	else if (caps[7] & 0x04)
L
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3514 3515 3516
		tape->tape_block_size = 1024;
}

3517
#ifdef CONFIG_IDE_PROC_FS
L
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3518 3519 3520 3521 3522
static void idetape_add_settings (ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;

/*
3523
 *			drive	setting name		read/write	data type	min			max			mul_factor			div_factor	data pointer				set function
L
Linus Torvalds 已提交
3524
 */
3525 3526
	ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
			1, 2, (u16 *)&tape->caps[16], NULL);
3527 3528 3529 3530 3531
	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);
3532 3533
	ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
			1, 1, (u16 *)&tape->caps[14], NULL);
3534 3535 3536 3537 3538 3539
	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_frequency,		NULL);
	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);
3540 3541
	ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
			1, &tape->debug_mask, NULL);
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3542
}
3543 3544 3545
#else
static inline void idetape_add_settings(ide_drive_t *drive) { ; }
#endif
L
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3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565

/*
 *	ide_setup is called to:
 *
 *		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).
 *
 *	Note that at this point ide.c already assigned us an irq, so that
 *	we can queue requests here and wait for their completion.
 */
static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
{
	unsigned long t1, tmid, tn, t;
	int speed;
	struct idetape_id_gcw gcw;
	int stage_size;
	struct sysinfo si;
3566
	u16 *ctl = (u16 *)&tape->caps[12];
L
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3567 3568 3569

	spin_lock_init(&tape->spinlock);
	drive->dsc_overlap = 1;
3570 3571 3572 3573
	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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3574 3575 3576 3577 3578 3579 3580 3581
	}
	/* 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;
3582
	tape->chrdev_dir = IDETAPE_DIR_NONE;
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3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593
	tape->pc = tape->pc_stack;
	tape->max_insert_speed = 10000;
	tape->speed_control = 1;
	*((unsigned short *) &gcw) = drive->id->config;
	if (gcw.drq_type == 1)
		set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);

	tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10;
	
	idetape_get_inquiry_results(drive);
	idetape_get_mode_sense_results(drive);
3594
	ide_tape_get_bsize_from_bdesc(drive);
L
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3595
	tape->user_bs_factor = 1;
3596
	tape->stage_size = *ctl * tape->tape_block_size;
L
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3597 3598
	while (tape->stage_size > 0xffff) {
		printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
3599 3600
		*ctl /= 2;
		tape->stage_size = *ctl * tape->tape_block_size;
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3601 3602 3603 3604 3605 3606 3607 3608
	}
	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;
	}

3609 3610
	/* 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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3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626

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

	/*
	 * 	Limit memory use for pipeline to 10% of physical memory
	 */
	si_meminfo(&si);
	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);
	tape->max_stages   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
	tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
	tape->max_pipeline = min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
	if (tape->max_stages == 0)
		tape->max_stages = tape->min_pipeline = tape->max_pipeline = 1;

	t1 = (tape->stage_size * HZ) / (speed * 1000);
3627
	tmid = (*(u16 *)&tape->caps[16] * 32 * HZ) / (speed * 125);
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3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641
	tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);

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

	/*
	 *	Ensure that the number we got makes sense; limit
	 *	it within IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
	 */
	tape->best_dsc_rw_frequency = max_t(unsigned long, min_t(unsigned long, t, IDETAPE_DSC_RW_MAX), IDETAPE_DSC_RW_MIN);
	printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
		"%dkB pipeline, %lums tDSC%s\n",
3642 3643
		drive->name, tape->name, *(u16 *)&tape->caps[14],
		(*(u16 *)&tape->caps[16] * 512) / tape->stage_size,
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3644 3645 3646 3647 3648 3649 3650 3651
		tape->stage_size / 1024,
		tape->max_stages * tape->stage_size / 1024,
		tape->best_dsc_rw_frequency * 1000 / HZ,
		drive->using_dma ? ", DMA":"");

	idetape_add_settings(drive);
}

3652
static void ide_tape_remove(ide_drive_t *drive)
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3653 3654 3655
{
	idetape_tape_t *tape = drive->driver_data;

3656
	ide_proc_unregister_driver(drive, tape->driver);
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Linus Torvalds 已提交
3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668

	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;

3669 3670
	BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);

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3671 3672
	drive->dsc_overlap = 0;
	drive->driver_data = NULL;
3673 3674
	device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
	device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor + 128));
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3675 3676 3677 3678 3679 3680
	idetape_devs[tape->minor] = NULL;
	g->private_data = NULL;
	put_disk(g);
	kfree(tape);
}

3681
#ifdef CONFIG_IDE_PROC_FS
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3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700
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

3701
static int ide_tape_probe(ide_drive_t *);
L
Linus Torvalds 已提交
3702 3703

static ide_driver_t idetape_driver = {
3704
	.gen_driver = {
3705
		.owner		= THIS_MODULE,
3706 3707 3708
		.name		= "ide-tape",
		.bus		= &ide_bus_type,
	},
3709 3710
	.probe			= ide_tape_probe,
	.remove			= ide_tape_remove,
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3711 3712 3713 3714 3715 3716 3717
	.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,
3718
#ifdef CONFIG_IDE_PROC_FS
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3719
	.proc			= idetape_proc,
3720
#endif
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3721 3722 3723 3724 3725
};

/*
 *	Our character device supporting functions, passed to register_chrdev.
 */
3726
static const struct file_operations idetape_fops = {
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3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774
	.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;

	if (!(tape = ide_tape_get(disk)))
		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,
};

3775
static int ide_tape_probe(ide_drive_t *drive)
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3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798
{
	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;
	if (!idetape_identify_device (drive)) {
		printk(KERN_ERR "ide-tape: %s: not supported by this version of ide-tape\n", drive->name);
		goto failed;
	}
	if (drive->scsi) {
		printk("ide-tape: passing drive %s to ide-scsi emulation.\n", drive->name);
		goto failed;
	}
	if (strstr(drive->id->model, "OnStream DI-")) {
		printk(KERN_WARNING "ide-tape: Use drive %s with ide-scsi emulation and osst.\n", drive->name);
		printk(KERN_WARNING "ide-tape: OnStream support will be removed soon from ide-tape!\n");
	}
3799
	tape = kzalloc(sizeof (idetape_tape_t), GFP_KERNEL);
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3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810
	if (tape == NULL) {
		printk(KERN_ERR "ide-tape: %s: Can't allocate a tape structure\n", drive->name);
		goto failed;
	}

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

	ide_init_disk(g, drive);

3811
	ide_proc_register_driver(drive, &idetape_driver);
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3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822

	kref_init(&tape->kref);

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

	g->private_data = &tape->driver;

	drive->driver_data = tape;

3823
	mutex_lock(&idetape_ref_mutex);
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3824 3825 3826
	for (minor = 0; idetape_devs[minor]; minor++)
		;
	idetape_devs[minor] = tape;
3827
	mutex_unlock(&idetape_ref_mutex);
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3828 3829 3830

	idetape_setup(drive, tape, minor);

3831 3832 3833 3834
	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);
3835

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3836 3837 3838 3839
	g->fops = &idetape_block_ops;
	ide_register_region(g);

	return 0;
3840

L
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3841 3842 3843
out_free_tape:
	kfree(tape);
failed:
3844
	return -ENODEV;
L
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3845 3846 3847 3848 3849 3850 3851
}

MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
MODULE_LICENSE("GPL");

static void __exit idetape_exit (void)
{
3852
	driver_unregister(&idetape_driver.gen_driver);
3853
	class_destroy(idetape_sysfs_class);
L
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3854 3855 3856
	unregister_chrdev(IDETAPE_MAJOR, "ht");
}

3857
static int __init idetape_init(void)
L
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3858
{
3859 3860 3861 3862 3863 3864 3865 3866 3867
	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
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3868 3869
	if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
		printk(KERN_ERR "ide-tape: Failed to register character device interface\n");
3870 3871
		error = -EBUSY;
		goto out_free_class;
L
Linus Torvalds 已提交
3872
	}
3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885

	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
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3886 3887
}

3888
MODULE_ALIAS("ide:*m-tape*");
L
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3889 3890 3891
module_init(idetape_init);
module_exit(idetape_exit);
MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);