ide-scsi.c

linux 内核源代码

/*
 * linux/drivers/scsi/ide-scsi.c	Version 0.9		Jul   4, 1999
 *
 * Copyright (C) 1996 - 1999 Gadi Oxman <[e-mail]>
 */

/*
 * Emulation of a SCSI host adapter for IDE ATAPI devices.
 *
 * With this driver, one can use the Linux SCSI drivers instead of the
 * native IDE ATAPI drivers.
 *
 * Ver 0.1   Dec  3 96   Initial version.
 * Ver 0.2   Jan 26 97   Fixed bug in cleanup_module() and added emulation
 *                        of MODE_SENSE_6/MODE_SELECT_6 for cdroms. Thanks
 *                        to Janos Farkas for pointing this out.
 *                       Avoid using bitfields in structures for m68k.
 *                       Added Scatter/Gather and DMA support.
 * Ver 0.4   Dec  7 97   Add support for ATAPI PD/CD drives.
 *                       Use variable timeout for each command.
 * Ver 0.5   Jan  2 98   Fix previous PD/CD support.
 *                       Allow disabling of SCSI-6 to SCSI-10 transformation.
 * Ver 0.6   Jan 27 98   Allow disabling of SCSI command translation layer
 *                        for access through /dev/sg.
 *                       Fix MODE_SENSE_6/MODE_SELECT_6/INQUIRY translation.
 * Ver 0.7   Dec 04 98   Ignore commands where lun != 0 to avoid multiple
 *                        detection of devices with CONFIG_SCSI_MULTI_LUN
 * Ver 0.8   Feb 05 99   Optical media need translation too. Reverse 0.7.
 * Ver 0.9   Jul 04 99   Fix a bug in SG_SET_TRANSFORM.
 * Ver 0.91  Jun 10 02   Fix "off by one" error in transforms
 * Ver 0.92  Dec 31 02   Implement new SCSI mid level API
 */

#define IDESCSI_VERSION "0.92"

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/blkdev.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/slab.h>
#include <linux/ide.h>
#include <linux/scatterlist.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/bitops.h>

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

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
#include <scsi/sg.h>

#define IDESCSI_DEBUG_LOG		0

typedef struct idescsi_pc_s {
	u8 c[12];				/* Actual packet bytes */
	int request_transfer;			/* Bytes to transfer */
	int actually_transferred;		/* Bytes actually transferred */
	int buffer_size;			/* Size of our data buffer */
	struct request *rq;			/* The corresponding request */
	u8 *buffer;				/* Data buffer */
	u8 *current_position;			/* Pointer into the above buffer */
	struct scatterlist *sg;			/* Scatter gather table */
	unsigned int sg_cnt;			/* Number of entries in sg */
	int b_count;				/* Bytes transferred from current entry */
	struct scsi_cmnd *scsi_cmd;		/* SCSI command */
	void (*done)(struct scsi_cmnd *);	/* Scsi completion routine */
	unsigned long flags;			/* Status/Action flags */
	unsigned long timeout;			/* Command timeout */
} idescsi_pc_t;

/*
 *	Packet command status bits.
 */
#define PC_DMA_IN_PROGRESS		0	/* 1 while DMA in progress */
#define PC_WRITING			1	/* Data direction */
#define PC_TIMEDOUT			3	/* command timed out */
#define PC_DMA_OK			4	/* Use DMA */

/*
 *	SCSI command transformation layer
 */
#define IDESCSI_SG_TRANSFORM		1	/* /dev/sg transformation */

/*
 *	Log flags
 */
#define IDESCSI_LOG_CMD			0	/* Log SCSI commands */

typedef struct ide_scsi_obj {
	ide_drive_t		*drive;
	ide_driver_t		*driver;
	struct gendisk		*disk;
	struct Scsi_Host	*host;

	idescsi_pc_t *pc;			/* Current packet command */
	unsigned long flags;			/* Status/Action flags */
	unsigned long transform;		/* SCSI cmd translation layer */
	unsigned long log;			/* log flags */
} idescsi_scsi_t;

static DEFINE_MUTEX(idescsi_ref_mutex);
static int idescsi_nocd;			/* Set by module param to skip cd */

#define ide_scsi_g(disk) \
	container_of((disk)->private_data, struct ide_scsi_obj, driver)

static struct ide_scsi_obj *ide_scsi_get(struct gendisk *disk)
{
	struct ide_scsi_obj *scsi = NULL;

	mutex_lock(&idescsi_ref_mutex);
	scsi = ide_scsi_g(disk);
	if (scsi)
		scsi_host_get(scsi->host);
	mutex_unlock(&idescsi_ref_mutex);
	return scsi;
}

static void ide_scsi_put(struct ide_scsi_obj *scsi)
{
	mutex_lock(&idescsi_ref_mutex);
	scsi_host_put(scsi->host);
	mutex_unlock(&idescsi_ref_mutex);
}

static inline idescsi_scsi_t *scsihost_to_idescsi(struct Scsi_Host *host)
{
	return (idescsi_scsi_t*) (&host[1]);
}

static inline idescsi_scsi_t *drive_to_idescsi(ide_drive_t *ide_drive)
{
	return scsihost_to_idescsi(ide_drive->driver_data);
}

/*
 *	Per ATAPI device status bits.
 */
#define IDESCSI_DRQ_INTERRUPT		0	/* DRQ interrupt device */

/*
 *	ide-scsi requests.
 */
#define IDESCSI_PC_RQ			90

static void idescsi_discard_data (ide_drive_t *drive, unsigned int bcount)
{
	while (bcount--)
		(void) HWIF(drive)->INB(IDE_DATA_REG);
}

static void idescsi_output_zeros (ide_drive_t *drive, unsigned int bcount)
{
	while (bcount--)
		HWIF(drive)->OUTB(0, IDE_DATA_REG);
}

/*
 *	PIO data transfer routines using the scatter gather table.
 */
static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigned int bcount)
{
	int count;
	char *buf;

	while (bcount) {
		count = min(pc->sg->length - pc->b_count, bcount);
		if (PageHighMem(sg_page(pc->sg))) {
			unsigned long flags;

			local_irq_save(flags);
			buf = kmap_atomic(sg_page(pc->sg), KM_IRQ0) +
					pc->sg->offset;
			drive->hwif->atapi_input_bytes(drive,
						buf + pc->b_count, count);
			kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);
			local_irq_restore(flags);
		} else {
			buf = sg_virt(pc->sg);
			drive->hwif->atapi_input_bytes(drive,
						buf + pc->b_count, count);
		}
		bcount -= count; pc->b_count += count;
		if (pc->b_count == pc->sg->length) {
			if (!--pc->sg_cnt)
				break;
			pc->sg = sg_next(pc->sg);
			pc->b_count = 0;
		}
	}

	if (bcount) {
		printk (KERN_ERR "ide-scsi: scatter gather table too small, discarding data\n");
		idescsi_discard_data (drive, bcount);
	}
}

static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigned int bcount)
{
	int count;
	char *buf;

	while (bcount) {
		count = min(pc->sg->length - pc->b_count, bcount);
		if (PageHighMem(sg_page(pc->sg))) {
			unsigned long flags;

			local_irq_save(flags);
			buf = kmap_atomic(sg_page(pc->sg), KM_IRQ0) +
						pc->sg->offset;
			drive->hwif->atapi_output_bytes(drive,
						buf + pc->b_count, count);
			kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);
			local_irq_restore(flags);
		} else {
			buf = sg_virt(pc->sg);
			drive->hwif->atapi_output_bytes(drive,
						buf + pc->b_count, count);
		}
		bcount -= count; pc->b_count += count;
		if (pc->b_count == pc->sg->length) {
			if (!--pc->sg_cnt)
				break;
			pc->sg = sg_next(pc->sg);
			pc->b_count = 0;
		}
	}

	if (bcount) {
		printk (KERN_ERR "ide-scsi: scatter gather table too small, padding with zeros\n");
		idescsi_output_zeros (drive, bcount);
	}
}

static void ide_scsi_hex_dump(u8 *data, int len)
{
	print_hex_dump(KERN_CONT, "", DUMP_PREFIX_NONE, 16, 1, data, len, 0);
}

static int idescsi_check_condition(ide_drive_t *drive, struct request *failed_command)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);
	idescsi_pc_t   *pc;
	struct request *rq;
	u8             *buf;

	/* stuff a sense request in front of our current request */
	pc = kzalloc(sizeof(idescsi_pc_t), GFP_ATOMIC);
	rq = kmalloc(sizeof(struct request), GFP_ATOMIC);
	buf = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_ATOMIC);
	if (!pc || !rq || !buf) {
		kfree(buf);
		kfree(rq);
		kfree(pc);
		return -ENOMEM;
	}
	ide_init_drive_cmd(rq);
	rq->special = (char *) pc;
	pc->rq = rq;
	pc->buffer = buf;
	pc->c[0] = REQUEST_SENSE;
	pc->c[4] = pc->request_transfer = pc->buffer_size = SCSI_SENSE_BUFFERSIZE;
	rq->cmd_type = REQ_TYPE_SENSE;
	pc->timeout = jiffies + WAIT_READY;
	/* NOTE! Save the failed packet command in "rq->buffer" */
	rq->buffer = (void *) failed_command->special;
	pc->scsi_cmd = ((idescsi_pc_t *) failed_command->special)->scsi_cmd;
	if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
		printk ("ide-scsi: %s: queue cmd = ", drive->name);
		ide_scsi_hex_dump(pc->c, 6);
	}
	rq->rq_disk = scsi->disk;
	return ide_do_drive_cmd(drive, rq, ide_preempt);
}

static int idescsi_end_request(ide_drive_t *, int, int);

static ide_startstop_t
idescsi_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
{
	if (HWIF(drive)->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT))
		/* force an abort */
		HWIF(drive)->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG);

	rq->errors++;

	idescsi_end_request(drive, 0, 0);

	return ide_stopped;
}

static ide_startstop_t
idescsi_atapi_abort(ide_drive_t *drive, struct request *rq)
{
#if IDESCSI_DEBUG_LOG
	printk(KERN_WARNING "idescsi_atapi_abort called for %lu\n",
			((idescsi_pc_t *) rq->special)->scsi_cmd->serial_number);
#endif
	rq->errors |= ERROR_MAX;

	idescsi_end_request(drive, 0, 0);

	return ide_stopped;
}

static int idescsi_end_request (ide_drive_t *drive, int uptodate, int nrsecs)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);
	struct request *rq = HWGROUP(drive)->rq;
	idescsi_pc_t *pc = (idescsi_pc_t *) rq->special;
	int log = test_bit(IDESCSI_LOG_CMD, &scsi->log);
	struct Scsi_Host *host;
	int errors = rq->errors;
	unsigned long flags;

	if (!blk_special_request(rq) && !blk_sense_request(rq)) {
		ide_end_request(drive, uptodate, nrsecs);
		return 0;
	}
	ide_end_drive_cmd (drive, 0, 0);
	if (blk_sense_request(rq)) {
		idescsi_pc_t *opc = (idescsi_pc_t *) rq->buffer;
		if (log) {
			printk ("ide-scsi: %s: wrap up check %lu, rst = ", drive->name, opc->scsi_cmd->serial_number);
			ide_scsi_hex_dump(pc->buffer, 16);
		}
		memcpy((void *) opc->scsi_cmd->sense_buffer, pc->buffer, SCSI_SENSE_BUFFERSIZE);
		kfree(pc->buffer);
		kfree(pc);
		kfree(rq);
		pc = opc;
		rq = pc->rq;
		pc->scsi_cmd->result = (CHECK_CONDITION << 1) |
					((test_bit(PC_TIMEDOUT, &pc->flags)?DID_TIME_OUT:DID_OK) << 16);
	} else if (test_bit(PC_TIMEDOUT, &pc->flags)) {
		if (log)
			printk (KERN_WARNING "ide-scsi: %s: timed out for %lu\n",
					drive->name, pc->scsi_cmd->serial_number);
		pc->scsi_cmd->result = DID_TIME_OUT << 16;
	} else if (errors >= ERROR_MAX) {
		pc->scsi_cmd->result = DID_ERROR << 16;
		if (log)
			printk ("ide-scsi: %s: I/O error for %lu\n", drive->name, pc->scsi_cmd->serial_number);
	} else if (errors) {
		if (log)
			printk ("ide-scsi: %s: check condition for %lu\n", drive->name, pc->scsi_cmd->serial_number);
		if (!idescsi_check_condition(drive, rq))
			/* we started a request sense, so we'll be back, exit for now */
			return 0;
		pc->scsi_cmd->result = (CHECK_CONDITION << 1) | (DID_OK << 16);