/*
 *  Copyright (C) 1994-1998	   Linus Torvalds & authors (see below)
 *  Copyright (C) 1998-2002	   Linux ATA Development
 *				      Andre Hedrick <andre@linux-ide.org>
 *  Copyright (C) 2003		   Red Hat <alan@redhat.com>
 *  Copyright (C) 2003-2005, 2007  Bartlomiej Zolnierkiewicz
 */

/*
 *  Mostly written by Mark Lord <mlord@pobox.com>
 *                and Gadi Oxman <gadio@netvision.net.il>
 *                and Andre Hedrick <andre@linux-ide.org>
 *
 * This is the IDE/ATA disk driver, as evolved from hd.c and ide.c.
 */

#define IDEDISK_VERSION	"1.18"

//#define DEBUG

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/leds.h>

#define _IDE_DISK

#include <linux/ide.h>

#include <asm/byteorder.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/div64.h>

struct ide_disk_obj {
	ide_drive_t	*drive;
	ide_driver_t	*driver;
	struct gendisk	*disk;
	struct kref	kref;
	unsigned int	openers;	/* protected by BKL for now */
};

static DEFINE_MUTEX(idedisk_ref_mutex);

#define to_ide_disk(obj) container_of(obj, struct ide_disk_obj, kref)

#define ide_disk_g(disk) \
	container_of((disk)->private_data, struct ide_disk_obj, driver)

static struct ide_disk_obj *ide_disk_get(struct gendisk *disk)
{
	struct ide_disk_obj *idkp = NULL;

	mutex_lock(&idedisk_ref_mutex);
	idkp = ide_disk_g(disk);
	if (idkp)
		kref_get(&idkp->kref);
	mutex_unlock(&idedisk_ref_mutex);
	return idkp;
}

static void ide_disk_release(struct kref *);

static void ide_disk_put(struct ide_disk_obj *idkp)
{
	mutex_lock(&idedisk_ref_mutex);
	kref_put(&idkp->kref, ide_disk_release);
	mutex_unlock(&idedisk_ref_mutex);
}

/*
 * lba_capacity_is_ok() performs a sanity check on the claimed "lba_capacity"
 * value for this drive (from its reported identification information).
 *
 * Returns:	1 if lba_capacity looks sensible
 *		0 otherwise
 *
 * It is called only once for each drive.
 */
static int lba_capacity_is_ok (struct hd_driveid *id)
{
	unsigned long lba_sects, chs_sects, head, tail;

	/* No non-LBA info .. so valid! */
	if (id->cyls == 0)
		return 1;

	/*
	 * The ATA spec tells large drives to return
	 * C/H/S = 16383/16/63 independent of their size.
	 * Some drives can be jumpered to use 15 heads instead of 16.
	 * Some drives can be jumpered to use 4092 cyls instead of 16383.
	 */
	if ((id->cyls == 16383
	     || (id->cyls == 4092 && id->cur_cyls == 16383)) &&
	    id->sectors == 63 &&
	    (id->heads == 15 || id->heads == 16) &&
	    (id->lba_capacity >= 16383*63*id->heads))
		return 1;

	lba_sects   = id->lba_capacity;
	chs_sects   = id->cyls * id->heads * id->sectors;

	/* perform a rough sanity check on lba_sects:  within 10% is OK */
	if ((lba_sects - chs_sects) < chs_sects/10)
		return 1;

	/* some drives have the word order reversed */
	head = ((lba_sects >> 16) & 0xffff);
	tail = (lba_sects & 0xffff);
	lba_sects = (head | (tail << 16));
	if ((lba_sects - chs_sects) < chs_sects/10) {
		id->lba_capacity = lba_sects;
		return 1;	/* lba_capacity is (now) good */
	}

	return 0;	/* lba_capacity value may be bad */
}

static const u8 ide_rw_cmds[] = {
	WIN_MULTREAD,
	WIN_MULTWRITE,
	WIN_MULTREAD_EXT,
	WIN_MULTWRITE_EXT,
	WIN_READ,
	WIN_WRITE,
	WIN_READ_EXT,
	WIN_WRITE_EXT,
	WIN_READDMA,
	WIN_WRITEDMA,
	WIN_READDMA_EXT,
	WIN_WRITEDMA_EXT,
};

static const u8 ide_data_phases[] = {
	TASKFILE_MULTI_IN,
	TASKFILE_MULTI_OUT,
	TASKFILE_IN,
	TASKFILE_OUT,
	TASKFILE_IN_DMA,
	TASKFILE_OUT_DMA,
};

static void ide_tf_set_cmd(ide_drive_t *drive, ide_task_t *task, u8 dma)
{
	u8 index, lba48, write;

	lba48 = (task->tf_flags & IDE_TFLAG_LBA48) ? 2 : 0;
	write = (task->tf_flags & IDE_TFLAG_WRITE) ? 1 : 0;

	if (dma)
		index = drive->vdma ? 4 : 8;
	else
		index = drive->mult_count ? 0 : 4;

	task->tf.command = ide_rw_cmds[index + lba48 + write];

	if (dma)
		index = 8; /* fixup index */

	task->data_phase = ide_data_phases[index / 2 + write];
}

/*
 * __ide_do_rw_disk() issues READ and WRITE commands to a disk,
 * using LBA if supported, or CHS otherwise, to address sectors.
 */
static ide_startstop_t __ide_do_rw_disk(ide_drive_t *drive, struct request *rq, sector_t block)
{
	ide_hwif_t *hwif	= HWIF(drive);
	unsigned int dma	= drive->using_dma;
	u16 nsectors		= (u16)rq->nr_sectors;
	u8 lba48		= (drive->addressing == 1) ? 1 : 0;
	ide_task_t		task;
	struct ide_taskfile	*tf = &task.tf;
	ide_startstop_t		rc;

	if ((hwif->host_flags & IDE_HFLAG_NO_LBA48_DMA) && lba48 && dma) {
		if (block + rq->nr_sectors > 1ULL << 28)
			dma = 0;
		else
			lba48 = 0;
	}

	if (!dma) {
		ide_init_sg_cmd(drive, rq);
		ide_map_sg(drive, rq);
	}

	memset(&task, 0, sizeof(task));
	task.tf_flags = IDE_TFLAG_NO_SELECT_MASK;  /* FIXME? */
	task.tf_flags |= (IDE_TFLAG_TF | IDE_TFLAG_DEVICE);

	if (drive->select.b.lba) {
		if (lba48) {
			pr_debug("%s: LBA=0x%012llx\n", drive->name,
					(unsigned long long)block);

			tf->hob_nsect = (nsectors >> 8) & 0xff;
			tf->hob_lbal  = (u8)(block >> 24);
			if (sizeof(block) != 4) {
				tf->hob_lbam = (u8)((u64)block >> 32);
				tf->hob_lbah = (u8)((u64)block >> 40);
			}

			tf->nsect  = nsectors & 0xff;
			tf->lbal   = (u8) block;
			tf->lbam   = (u8)(block >>  8);
			tf->lbah   = (u8)(block >> 16);

			task.tf_flags |= (IDE_TFLAG_LBA48 | IDE_TFLAG_HOB);
		} else {
			tf->nsect  = nsectors & 0xff;
			tf->lbal   = block;
			tf->lbam   = block >>= 8;
			tf->lbah   = block >>= 8;
			tf->device = (block >> 8) & 0xf;
		}
	} else {
		unsigned int sect,head,cyl,track;
		track = (int)block / drive->sect;
		sect  = (int)block % drive->sect + 1;
		head  = track % drive->head;
		cyl   = track / drive->head;

		pr_debug("%s: CHS=%u/%u/%u\n", drive->name, cyl, head, sect);

		tf->nsect  = nsectors & 0xff;
		tf->lbal   = sect;
		tf->lbam   = cyl;
		tf->lbah   = cyl >> 8;
		tf->device = head;
	}

	if (rq_data_dir(rq))
		task.tf_flags |= IDE_TFLAG_WRITE;

	ide_tf_set_cmd(drive, &task, dma);
	if (!dma)
		hwif->data_phase = task.data_phase;
	task.rq = rq;

	rc = do_rw_taskfile(drive, &task);

	if (rc == ide_stopped && dma) {
		/* fallback to PIO */
		task.tf_flags |= IDE_TFLAG_DMA_PIO_FALLBACK;
		ide_tf_set_cmd(drive, &task, 0);
		hwif->data_phase = task.data_phase;
		ide_init_sg_cmd(drive, rq);
		rc = do_rw_taskfile(drive, &task);
	}

	return rc;
}

/*
 * 268435455  == 137439 MB or 28bit limit
 * 320173056  == 163929 MB or 48bit addressing
 * 1073741822 == 549756 MB or 48bit addressing fake drive
 */

static ide_startstop_t ide_do_rw_disk (ide_drive_t *drive, struct request *rq, sector_t block)
{
	ide_hwif_t *hwif = HWIF(drive);

	BUG_ON(drive->blocked);

	if (!blk_fs_request(rq)) {
		blk_dump_rq_flags(rq, "ide_do_rw_disk - bad command");
		ide_end_request(drive, 0, 0);
		return ide_stopped;
	}

	ledtrig_ide_activity();

	pr_debug("%s: %sing: block=%llu, sectors=%lu, buffer=0x%08lx\n",
		 drive->name, rq_data_dir(rq) == READ ? "read" : "writ",
		 (unsigned long long)block, rq->nr_sectors,
		 (unsigned long)rq->buffer);

	if (hwif->rw_disk)
		hwif->rw_disk(drive, rq);

	return __ide_do_rw_disk(drive, rq, block);
}

/*
 * Queries for true maximum capacity of the drive.
 * Returns maximum LBA address (> 0) of the drive, 0 if failed.
 */
static u64 idedisk_read_native_max_address(ide_drive_t *drive, int lba48)
{
	ide_task_t args;
	struct ide_taskfile *tf = &args.tf;
	u64 addr = 0;

	/* Create IDE/ATA command request structure */
	memset(&args, 0, sizeof(ide_task_t));
	if (lba48)
		tf->command = WIN_READ_NATIVE_MAX_EXT;
	else
		tf->command = WIN_READ_NATIVE_MAX;
	tf->device  = ATA_LBA;
	args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
	if (lba48)
		args.tf_flags |= (IDE_TFLAG_LBA48 | IDE_TFLAG_HOB);
	/* submit command request */
	ide_no_data_taskfile(drive, &args);

	/* if OK, compute maximum address value */
	if ((tf->status & 0x01) == 0)
		addr = ide_get_lba_addr(tf, lba48) + 1;

	return addr;
}

/*
 * Sets maximum virtual LBA address of the drive.
 * Returns new maximum virtual LBA address (> 0) or 0 on failure.
 */
static u64 idedisk_set_max_address(ide_drive_t *drive, u64 addr_req, int lba48)
{
	ide_task_t args;
	struct ide_taskfile *tf = &args.tf;
	u64 addr_set = 0;

	addr_req--;
	/* Create IDE/ATA command request structure */
	memset(&args, 0, sizeof(ide_task_t));
	tf->lbal     = (addr_req >>  0) & 0xff;
	tf->lbam     = (addr_req >>= 8) & 0xff;
	tf->lbah     = (addr_req >>= 8) & 0xff;
	if (lba48) {
		tf->hob_lbal = (addr_req >>= 8) & 0xff;
		tf->hob_lbam = (addr_req >>= 8) & 0xff;
		tf->hob_lbah = (addr_req >>= 8) & 0xff;
		tf->command  = WIN_SET_MAX_EXT;
	} else {
		tf->device   = (addr_req >>= 8) & 0x0f;
		tf->command  = WIN_SET_MAX;
	}
	tf->device |= ATA_LBA;
	args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
	if (lba48)
		args.tf_flags |= (IDE_TFLAG_LBA48 | IDE_TFLAG_HOB);
	/* submit command request */
	ide_no_data_taskfile(drive, &args);
	/* if OK, compute maximum address value */
	if ((tf->status & 0x01) == 0)
		addr_set = ide_get_lba_addr(tf, lba48) + 1;

	return addr_set;
}

static unsigned long long sectors_to_MB(unsigned long long n)
{
	n <<= 9;		/* make it bytes */
	do_div(n, 1000000);	/* make it MB */
	return n;
}

/*
 * Bits 10 of command_set_1 and cfs_enable_1 must be equal,
 * so on non-buggy drives we need test only one.
 * However, we should also check whether these fields are valid.
 */
static inline int idedisk_supports_hpa(const struct hd_driveid *id)
{
	return (id->command_set_1 & 0x0400) && (id->cfs_enable_1 & 0x0400);
}

/*
 * The same here.
 */
static inline int idedisk_supports_lba48(const struct hd_driveid *id)
{
	return (id->command_set_2 & 0x0400) && (id->cfs_enable_2 & 0x0400)
	       && id->lba_capacity_2;
}

/*
 * Some disks report total number of sectors instead of
 * maximum sector address.  We list them here.
 */
static const struct drive_list_entry hpa_list[] = {
	{ "ST340823A",	NULL },
	{ "ST320413A",	NULL },
	{ "ST310211A",	NULL },
	{ NULL,		NULL }
};

static void idedisk_check_hpa(ide_drive_t *drive)
{
	unsigned long long capacity, set_max;
	int lba48 = idedisk_supports_lba48(drive->id);

	capacity = drive->capacity64;

	set_max = idedisk_read_native_max_address(drive, lba48);

	if (ide_in_drive_list(drive->id, hpa_list)) {
		/*
		 * Since we are inclusive wrt to firmware revisions do this
		 * extra check and apply the workaround only when needed.
		 */
		if (set_max == capacity + 1)
			set_max--;
	}

	if (set_max <= capacity)
		return;

	printk(KERN_INFO "%s: Host Protected Area detected.\n"
			 "\tcurrent capacity is %llu sectors (%llu MB)\n"
			 "\tnative  capacity is %llu sectors (%llu MB)\n",
			 drive->name,
			 capacity, sectors_to_MB(capacity),
			 set_max, sectors_to_MB(set_max));

	set_max = idedisk_set_max_address(drive, set_max, lba48);

	if (set_max) {
		drive->capacity64 = set_max;
		printk(KERN_INFO "%s: Host Protected Area disabled.\n",
				 drive->name);
	}
}

/*
 * Compute drive->capacity, the full capacity of the drive
 * Called with drive->id != NULL.
 *
 * To compute capacity, this uses either of
 *
 *    1. CHS value set by user       (whatever user sets will be trusted)
 *    2. LBA value from target drive (require new ATA feature)
 *    3. LBA value from system BIOS  (new one is OK, old one may break)
 *    4. CHS value from system BIOS  (traditional style)
 *
 * in above order (i.e., if value of higher priority is available,
 * reset will be ignored).
 */
static void init_idedisk_capacity (ide_drive_t  *drive)
{
	struct hd_driveid *id = drive->id;
	/*
	 * If this drive supports the Host Protected Area feature set,
	 * then we may need to change our opinion about the drive's capacity.
	 */
	int hpa = idedisk_supports_hpa(id);

	if (idedisk_supports_lba48(id)) {
		/* drive speaks 48-bit LBA */
		drive->select.b.lba = 1;
		drive->capacity64 = id->lba_capacity_2;
		if (hpa)
			idedisk_check_hpa(drive);
	} else if ((id->capability & 2) && lba_capacity_is_ok(id)) {
		/* drive speaks 28-bit LBA */
		drive->select.b.lba = 1;
		drive->capacity64 = id->lba_capacity;
		if (hpa)
			idedisk_check_hpa(drive);
	} else {
		/* drive speaks boring old 28-bit CHS */
		drive->capacity64 = drive->cyl * drive->head * drive->sect;
	}
}

static sector_t idedisk_capacity (ide_drive_t *drive)
{
	return drive->capacity64 - drive->sect0;
}

#ifdef CONFIG_IDE_PROC_FS
static int smart_enable(ide_drive_t *drive)
{
	ide_task_t args;
	struct ide_taskfile *tf = &args.tf;

	memset(&args, 0, sizeof(ide_task_t));
	tf->feature = SMART_ENABLE;
	tf->lbam    = SMART_LCYL_PASS;
	tf->lbah    = SMART_HCYL_PASS;
	tf->command = WIN_SMART;
	args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
	return ide_no_data_taskfile(drive, &args);
}

static int get_smart_data(ide_drive_t *drive, u8 *buf, u8 sub_cmd)
{
	ide_task_t args;
	struct ide_taskfile *tf = &args.tf;