/*
 * libata-acpi.c
 * Provides ACPI support for PATA/SATA.
 *
 * Copyright (C) 2006 Intel Corp.
 * Copyright (C) 2006 Randy Dunlap
 */

#include <linux/ata.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
#include <linux/libata.h>
#include <linux/pci.h>
#include "libata.h"

#include <acpi/acpi_bus.h>
#include <acpi/acnames.h>
#include <acpi/acnamesp.h>
#include <acpi/acparser.h>
#include <acpi/acexcep.h>
#include <acpi/acmacros.h>
#include <acpi/actypes.h>

#define NO_PORT_MULT		0xffff
#define SATA_ADR(root,pmp)	(((root) << 16) | (pmp))

#define REGS_PER_GTF		7
struct ata_acpi_gtf {
	u8	tf[REGS_PER_GTF];	/* regs. 0x1f1 - 0x1f7 */
} __packed;

/*
 *	Helper - belongs in the PCI layer somewhere eventually
 */
static int is_pci_dev(struct device *dev)
{
	return (dev->bus == &pci_bus_type);
}

static void ata_acpi_associate_sata_port(struct ata_port *ap)
{
	acpi_integer adr = SATA_ADR(ap->port_no, NO_PORT_MULT);

	ap->device->acpi_handle = acpi_get_child(ap->host->acpi_handle, adr);
}

static void ata_acpi_associate_ide_port(struct ata_port *ap)
{
	int max_devices, i;

	ap->acpi_handle = acpi_get_child(ap->host->acpi_handle, ap->port_no);
	if (!ap->acpi_handle)
		return;

	max_devices = 1;
	if (ap->flags & ATA_FLAG_SLAVE_POSS)
		max_devices++;

	for (i = 0; i < max_devices; i++) {
		struct ata_device *dev = &ap->device[i];

		dev->acpi_handle = acpi_get_child(ap->acpi_handle, i);
	}
}

/**
 * ata_acpi_associate - associate ATA host with ACPI objects
 * @host: target ATA host
 *
 * Look up ACPI objects associated with @host and initialize
 * acpi_handle fields of @host, its ports and devices accordingly.
 *
 * LOCKING:
 * EH context.
 *
 * RETURNS:
 * 0 on success, -errno on failure.
 */
void ata_acpi_associate(struct ata_host *host)
{
	int i;

	if (!is_pci_dev(host->dev) || libata_noacpi)
		return;

	host->acpi_handle = DEVICE_ACPI_HANDLE(host->dev);
	if (!host->acpi_handle)
		return;

	for (i = 0; i < host->n_ports; i++) {
		struct ata_port *ap = host->ports[i];

		if (host->ports[0]->flags & ATA_FLAG_ACPI_SATA)
			ata_acpi_associate_sata_port(ap);
		else
			ata_acpi_associate_ide_port(ap);
	}
}

/**
 * ata_dev_get_GTF - get the drive bootup default taskfile settings
 * @dev: target ATA device
 * @gtf: output parameter for buffer containing _GTF taskfile arrays
 * @ptr_to_free: pointer which should be freed
 *
 * This applies to both PATA and SATA drives.
 *
 * The _GTF method has no input parameters.
 * It returns a variable number of register set values (registers
 * hex 1F1..1F7, taskfiles).
 * The <variable number> is not known in advance, so have ACPI-CA
 * allocate the buffer as needed and return it, then free it later.
 *
 * LOCKING:
 * EH context.
 *
 * RETURNS:
 * Number of taskfiles on success, 0 if _GTF doesn't exist or doesn't
 * contain valid data.  -errno on other errors.
 */
static int ata_dev_get_GTF(struct ata_device *dev, struct ata_acpi_gtf **gtf,
			   void **ptr_to_free)
{
	struct ata_port *ap = dev->ap;
	acpi_status status;
	struct acpi_buffer output;
	union acpi_object *out_obj;
	int rc = 0;

	/* set up output buffer */
	output.length = ACPI_ALLOCATE_BUFFER;
	output.pointer = NULL;	/* ACPI-CA sets this; save/free it later */

	if (ata_msg_probe(ap))
		ata_dev_printk(dev, KERN_DEBUG, "%s: ENTER: port#: %d\n",
			       __FUNCTION__, ap->port_no);

	/* _GTF has no input parameters */
	status = acpi_evaluate_object(dev->acpi_handle, "_GTF", NULL, &output);

	if (ACPI_FAILURE(status)) {
		if (status != AE_NOT_FOUND) {
			ata_dev_printk(dev, KERN_WARNING,
				       "_GTF evaluation failed (AE 0x%x)\n",
				       status);
			rc = -EIO;
		}
		goto out_free;
	}

	if (!output.length || !output.pointer) {
		if (ata_msg_probe(ap))
			ata_dev_printk(dev, KERN_DEBUG, "%s: Run _GTF: "
				"length or ptr is NULL (0x%llx, 0x%p)\n",
				__FUNCTION__,
				(unsigned long long)output.length,
				output.pointer);
		goto out_free;
	}

	out_obj = output.pointer;
	if (out_obj->type != ACPI_TYPE_BUFFER) {
		ata_dev_printk(dev, KERN_WARNING,
			       "_GTF unexpected object type 0x%x\n",
			       out_obj->type);
		rc = -EINVAL;
		goto out_free;
	}

	if (out_obj->buffer.length % REGS_PER_GTF) {
		ata_dev_printk(dev, KERN_WARNING,
			       "unexpected _GTF length (%d)\n",
			       out_obj->buffer.length);
		rc = -EINVAL;
		goto out_free;
	}

	*ptr_to_free = out_obj;
	*gtf = (void *)out_obj->buffer.pointer;
	rc = out_obj->buffer.length / REGS_PER_GTF;

	if (ata_msg_probe(ap))
		ata_dev_printk(dev, KERN_DEBUG, "%s: returning "
			"gtf=%p, gtf_count=%d, ptr_to_free=%p\n",
			__FUNCTION__, *gtf, rc, *ptr_to_free);
	return rc;

 out_free:
	kfree(output.pointer);
	return rc;
}

/**
 * taskfile_load_raw - send taskfile registers to host controller
 * @dev: target ATA device
 * @gtf: raw ATA taskfile register set (0x1f1 - 0x1f7)
 *
 * Outputs ATA taskfile to standard ATA host controller using MMIO
 * or PIO as indicated by the ATA_FLAG_MMIO flag.
 * Writes the control, feature, nsect, lbal, lbam, and lbah registers.
 * Optionally (ATA_TFLAG_LBA48) writes hob_feature, hob_nsect,
 * hob_lbal, hob_lbam, and hob_lbah.
 *
 * This function waits for idle (!BUSY and !DRQ) after writing
 * registers.  If the control register has a new value, this
 * function also waits for idle after writing control and before
 * writing the remaining registers.
 *
 * LOCKING:
 * EH context.
 *
 * RETURNS:
 * 0 on success, -errno on failure.
 */
static int taskfile_load_raw(struct ata_device *dev,
			      const struct ata_acpi_gtf *gtf)
{
	struct ata_port *ap = dev->ap;
	struct ata_taskfile tf, rtf;
	unsigned int err_mask;

	if ((gtf->tf[0] == 0) && (gtf->tf[1] == 0) && (gtf->tf[2] == 0)
	    && (gtf->tf[3] == 0) && (gtf->tf[4] == 0) && (gtf->tf[5] == 0)
	    && (gtf->tf[6] == 0))
		return 0;

	ata_tf_init(dev, &tf);

	/* convert gtf to tf */
	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE; /* TBD */
	tf.protocol = ATA_PROT_NODATA;
	tf.feature = gtf->tf[0];	/* 0x1f1 */
	tf.nsect   = gtf->tf[1];	/* 0x1f2 */
	tf.lbal    = gtf->tf[2];	/* 0x1f3 */
	tf.lbam    = gtf->tf[3];	/* 0x1f4 */
	tf.lbah    = gtf->tf[4];	/* 0x1f5 */
	tf.device  = gtf->tf[5];	/* 0x1f6 */
	tf.command = gtf->tf[6];	/* 0x1f7 */

	if (ata_msg_probe(ap))
		ata_dev_printk(dev, KERN_DEBUG, "executing ACPI cmd "
			       "%02x/%02x:%02x:%02x:%02x:%02x:%02x\n",
			       tf.command, tf.feature, tf.nsect,
			       tf.lbal, tf.lbam, tf.lbah, tf.device);

	rtf = tf;
	err_mask = ata_exec_internal(dev, &rtf, NULL, DMA_NONE, NULL, 0);
	if (err_mask) {
		ata_dev_printk(dev, KERN_ERR,
			"ACPI cmd %02x/%02x:%02x:%02x:%02x:%02x:%02x failed "
			"(Emask=0x%x Stat=0x%02x Err=0x%02x)\n",
			tf.command, tf.feature, tf.nsect, tf.lbal, tf.lbam,
			tf.lbah, tf.device, err_mask, rtf.command, rtf.feature);
		return -EIO;
	}

	return 0;
}

/**
 * ata_acpi_exec_tfs - get then write drive taskfile settings
 * @dev: target ATA device
 *
 * Evaluate _GTF and excute returned taskfiles.
 *
 * LOCKING:
 * EH context.
 *
 * RETURNS:
 * Number of executed taskfiles on success, 0 if _GTF doesn't exist or
 * doesn't contain valid data.  -errno on other errors.
 */
static int ata_acpi_exec_tfs(struct ata_device *dev)
{
	struct ata_acpi_gtf *gtf = NULL;
	void *ptr_to_free = NULL;
	int gtf_count, i, rc;

	/* get taskfiles */
	rc = ata_dev_get_GTF(dev, &gtf, &ptr_to_free);
	if (rc < 0)
		return rc;
	gtf_count = rc;

	/* execute them */
	for (i = 0, rc = 0; i < gtf_count; i++) {
		int tmp;

		/* ACPI errors are eventually ignored.  Run till the
		 * end even after errors.
		 */
		tmp = taskfile_load_raw(dev, gtf++);
		if (!rc)
			rc = tmp;
	}

	kfree(ptr_to_free);

	if (rc == 0)
		return gtf_count;
	return rc;
}

/**
 * ata_acpi_push_id - send Identify data to drive
 * @dev: target ATA device
 *
 * _SDD ACPI object: for SATA mode only
 * Must be after Identify (Packet) Device -- uses its data
 * ATM this function never returns a failure.  It is an optional
 * method and if it fails for whatever reason, we should still
 * just keep going.
 *
 * LOCKING:
 * EH context.
 *
 * RETURNS:
 * 0 on success, -errno on failure.
 */
static int ata_acpi_push_id(struct ata_device *dev)
{
	struct ata_port *ap = dev->ap;
	int err;
	acpi_status status;
	struct acpi_object_list input;
	union acpi_object in_params[1];

	if (ata_msg_probe(ap))
		ata_dev_printk(dev, KERN_DEBUG, "%s: ix = %d, port#: %d\n",
			       __FUNCTION__, dev->devno, ap->port_no);

	/* Give the drive Identify data to the drive via the _SDD method */
	/* _SDD: set up input parameters */
	input.count = 1;
	input.pointer = in_params;
	in_params[0].type = ACPI_TYPE_BUFFER;
	in_params[0].buffer.length = sizeof(dev->id[0]) * ATA_ID_WORDS;
	in_params[0].buffer.pointer = (u8 *)dev->id;
	/* Output buffer: _SDD has no output */

	/* It's OK for _SDD to be missing too. */
	swap_buf_le16(dev->id, ATA_ID_WORDS);
	status = acpi_evaluate_object(dev->acpi_handle, "_SDD", &input, NULL);
	swap_buf_le16(dev->id, ATA_ID_WORDS);

	err = ACPI_FAILURE(status) ? -EIO : 0;
	if (err < 0)
		ata_dev_printk(dev, KERN_WARNING,
			       "ACPI _SDD failed (AE 0x%x)\n", status);

	return err;
}

/**
 * ata_acpi_on_resume - ATA ACPI hook called on resume
 * @ap: target ATA port
 *
 * This function is called when @ap is resumed - right after port
 * itself is resumed but before any EH action is taken.
 *
 * LOCKING:
 * EH context.
 */
void ata_acpi_on_resume(struct ata_port *ap)
{
	int i;

	/* schedule _GTF */
	for (i = 0; i < ATA_MAX_DEVICES; i++)
		ap->device[i].flags |= ATA_DFLAG_ACPI_PENDING;
}

/**
 * ata_acpi_on_devcfg - ATA ACPI hook called on device donfiguration
 * @dev: target ATA device
 *
 * This function is called when @dev is about to be configured.
 * IDENTIFY data might have been modified after this hook is run.
 *
 * LOCKING:
 * EH context.
 *
 * RETURNS:
 * Positive number if IDENTIFY data needs to be refreshed, 0 if not,
 * -errno on failure.
 */
int ata_acpi_on_devcfg(struct ata_device *dev)
{
	struct ata_port *ap = dev->ap;
	struct ata_eh_context *ehc = &ap->eh_context;
	int acpi_sata = ap->flags & ATA_FLAG_ACPI_SATA;
	int rc;

	/* XXX: _STM isn't implemented yet, skip if IDE for now */
	if (!acpi_sata)
		return 0;

	if (!dev->acpi_handle)
		return 0;

	/* do we need to do _GTF? */
	if (!(dev->flags & ATA_DFLAG_ACPI_PENDING) &&
	    !(acpi_sata && (ehc->i.flags & ATA_EHI_DID_HARDRESET)))
		return 0;

	/* do _SDD if SATA */
	if (acpi_sata) {
		rc = ata_acpi_push_id(dev);
		if (rc)
			goto acpi_err;
	}

	/* do _GTF */
	rc = ata_acpi_exec_tfs(dev);
	if (rc < 0)
		goto acpi_err;

	dev->flags &= ~ATA_DFLAG_ACPI_PENDING;

	/* refresh IDENTIFY page if any _GTF command has been executed */
	if (rc > 0) {
		rc = ata_dev_reread_id(dev, 0);
		if (rc < 0) {
			ata_dev_printk(dev, KERN_ERR, "failed to IDENTIFY "
				       "after ACPI commands\n");
			return rc;
		}
	}

	return 0;

 acpi_err:
	/* let EH retry on the first failure, disable ACPI on the second */
	if (dev->flags & ATA_DFLAG_ACPI_FAILED) {
		ata_dev_printk(dev, KERN_WARNING, "ACPI on devcfg failed the "
			       "second time, disabling (errno=%d)\n", rc);

		dev->acpi_handle = NULL;

		/* if port is working, request IDENTIFY reload and continue */
		if (!(ap->pflags & ATA_PFLAG_FROZEN))
			rc = 1;
	}
	dev->flags |= ATA_DFLAG_ACPI_FAILED;
	return rc;
}