path: root/drivers/ide/ide-disk.c

/*
 *  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"

#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>
#include <linux/ide.h>
#include <linux/hdreg.h>

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

#if !defined(CONFIG_DEBUG_BLOCK_EXT_DEVT)
#define IDE_DISK_MINORS		(1 << PARTN_BITS)
#else
#define IDE_DISK_MINORS		0
#endif

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 void ide_disk_release(struct kref *);

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) {
		if (ide_device_get(idkp->drive))
			idkp = NULL;
		else
			kref_get(&idkp->kref);
	}
	mutex_unlock(&idedisk_ref_mutex);
	return idkp;
}

static void ide_disk_put(struct ide_disk_obj *idkp)
{
	ide_drive_t *drive = idkp->drive;

	mutex_lock(&idedisk_ref_mutex);
	kref_put(&idkp->kref, ide_disk_release);
	ide_device_put(drive);
	mutex_unlock(&idedisk_ref_mutex);
}

static const u8 ide_rw_cmds[] = {
	ATA_CMD_READ_MULTI,
	ATA_CMD_WRITE_MULTI,
	ATA_CMD_READ_MULTI_EXT,
	ATA_CMD_WRITE_MULTI_EXT,
	ATA_CMD_PIO_READ,
	ATA_CMD_PIO_WRITE,
	ATA_CMD_PIO_READ_EXT,
	ATA_CMD_PIO_WRITE_EXT,
	ATA_CMD_READ,
	ATA_CMD_WRITE,
	ATA_CMD_READ_EXT,
	ATA_CMD_WRITE_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 = 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);
	u16 nsectors		= (u16)rq->nr_sectors;
	u8 lba48		= !!(