libata-scsi.c

linux 内核源代码

	struct scsi_cmnd *scmd = qc->scsicmd;
	struct ata_taskfile *tf = &qc->tf;
	const u8 *cdb = scmd->cmnd;

	if (scmd->cmd_len < 5)
		goto invalid_fld;

	tf->flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
	tf->protocol = ATA_PROT_NODATA;
	if (cdb[1] & 0x1) {
		;	/* ignore IMMED bit, violates sat-r05 */
	}
	if (cdb[4] & 0x2)
		goto invalid_fld;       /* LOEJ bit set not supported */
	if (((cdb[4] >> 4) & 0xf) != 0)
		goto invalid_fld;       /* power conditions not supported */

	if (qc->dev->horkage & ATA_HORKAGE_SKIP_PM) {
		/* the device lacks PM support, finish without doing anything */
		scmd->result = SAM_STAT_GOOD;
		return 1;
	}

	if (cdb[4] & 0x1) {
		tf->nsect = 1;	/* 1 sector, lba=0 */

		if (qc->dev->flags & ATA_DFLAG_LBA) {
			tf->flags |= ATA_TFLAG_LBA;

			tf->lbah = 0x0;
			tf->lbam = 0x0;
			tf->lbal = 0x0;
			tf->device |= ATA_LBA;
		} else {
			/* CHS */
			tf->lbal = 0x1; /* sect */
			tf->lbam = 0x0; /* cyl low */
			tf->lbah = 0x0; /* cyl high */
		}

		tf->command = ATA_CMD_VERIFY;	/* READ VERIFY */
	} else {
		/* XXX: This is for backward compatibility, will be
		 * removed.  Read Documentation/feature-removal-schedule.txt
		 * for more info.
		 */
		if ((qc->dev->flags & ATA_DFLAG_SPUNDOWN) &&
		    (system_state == SYSTEM_HALT ||
		     system_state == SYSTEM_POWER_OFF)) {
			static unsigned long warned;

			if (!test_and_set_bit(0, &warned)) {
				ata_dev_printk(qc->dev, KERN_WARNING,
					"DISK MIGHT NOT BE SPUN DOWN PROPERLY. "
					"UPDATE SHUTDOWN UTILITY\n");
				ata_dev_printk(qc->dev, KERN_WARNING,
					"For more info, visit "
					"http://linux-ata.org/shutdown.html\n");

				/* ->scsi_done is not used, use it for
				 * delayed completion.
				 */
				scmd->scsi_done = qc->scsidone;
				qc->scsidone = ata_delayed_done;
			}
			scmd->result = SAM_STAT_GOOD;
			return 1;
		}

		/* Issue ATA STANDBY IMMEDIATE command */
		tf->command = ATA_CMD_STANDBYNOW1;
	}

	/*
	 * Standby and Idle condition timers could be implemented but that
	 * would require libata to implement the Power condition mode page
	 * and allow the user to change it. Changing mode pages requires
	 * MODE SELECT to be implemented.
	 */

	return 0;

invalid_fld:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x0);
	/* "Invalid field in cbd" */
	return 1;
}


/**
 *	ata_scsi_flush_xlat - Translate SCSI SYNCHRONIZE CACHE command
 *	@qc: Storage for translated ATA taskfile
 *
 *	Sets up an ATA taskfile to issue FLUSH CACHE or
 *	FLUSH CACHE EXT.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */
static unsigned int ata_scsi_flush_xlat(struct ata_queued_cmd *qc)
{
	struct ata_taskfile *tf = &qc->tf;

	tf->flags |= ATA_TFLAG_DEVICE;
	tf->protocol = ATA_PROT_NODATA;

	if (qc->dev->flags & ATA_DFLAG_FLUSH_EXT)
		tf->command = ATA_CMD_FLUSH_EXT;
	else
		tf->command = ATA_CMD_FLUSH;

	/* flush is critical for IO integrity, consider it an IO command */
	qc->flags |= ATA_QCFLAG_IO;

	return 0;
}

/**
 *	scsi_6_lba_len - Get LBA and transfer length
 *	@cdb: SCSI command to translate
 *
 *	Calculate LBA and transfer length for 6-byte commands.
 *
 *	RETURNS:
 *	@plba: the LBA
 *	@plen: the transfer length
 */
static void scsi_6_lba_len(const u8 *cdb, u64 *plba, u32 *plen)
{
	u64 lba = 0;
	u32 len;

	VPRINTK("six-byte command\n");

	lba |= ((u64)(cdb[1] & 0x1f)) << 16;
	lba |= ((u64)cdb[2]) << 8;
	lba |= ((u64)cdb[3]);

	len = cdb[4];

	*plba = lba;
	*plen = len;
}

/**
 *	scsi_10_lba_len - Get LBA and transfer length
 *	@cdb: SCSI command to translate
 *
 *	Calculate LBA and transfer length for 10-byte commands.
 *
 *	RETURNS:
 *	@plba: the LBA
 *	@plen: the transfer length
 */
static void scsi_10_lba_len(const u8 *cdb, u64 *plba, u32 *plen)
{
	u64 lba = 0;
	u32 len = 0;

	VPRINTK("ten-byte command\n");

	lba |= ((u64)cdb[2]) << 24;
	lba |= ((u64)cdb[3]) << 16;
	lba |= ((u64)cdb[4]) << 8;
	lba |= ((u64)cdb[5]);

	len |= ((u32)cdb[7]) << 8;
	len |= ((u32)cdb[8]);

	*plba = lba;
	*plen = len;
}

/**
 *	scsi_16_lba_len - Get LBA and transfer length
 *	@cdb: SCSI command to translate
 *
 *	Calculate LBA and transfer length for 16-byte commands.
 *
 *	RETURNS:
 *	@plba: the LBA
 *	@plen: the transfer length
 */
static void scsi_16_lba_len(const u8 *cdb, u64 *plba, u32 *plen)
{
	u64 lba = 0;
	u32 len = 0;

	VPRINTK("sixteen-byte command\n");

	lba |= ((u64)cdb[2]) << 56;
	lba |= ((u64)cdb[3]) << 48;
	lba |= ((u64)cdb[4]) << 40;
	lba |= ((u64)cdb[5]) << 32;
	lba |= ((u64)cdb[6]) << 24;
	lba |= ((u64)cdb[7]) << 16;
	lba |= ((u64)cdb[8]) << 8;
	lba |= ((u64)cdb[9]);

	len |= ((u32)cdb[10]) << 24;
	len |= ((u32)cdb[11]) << 16;
	len |= ((u32)cdb[12]) << 8;
	len |= ((u32)cdb[13]);

	*plba = lba;
	*plen = len;
}

/**
 *	ata_scsi_verify_xlat - Translate SCSI VERIFY command into an ATA one
 *	@qc: Storage for translated ATA taskfile
 *
 *	Converts SCSI VERIFY command to an ATA READ VERIFY command.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */
static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;
	struct ata_taskfile *tf = &qc->tf;
	struct ata_device *dev = qc->dev;
	u64 dev_sectors = qc->dev->n_sectors;
	const u8 *cdb = scmd->cmnd;
	u64 block;
	u32 n_block;

	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf->protocol = ATA_PROT_NODATA;

	if (cdb[0] == VERIFY) {
		if (scmd->cmd_len < 10)
			goto invalid_fld;
		scsi_10_lba_len(cdb, &block, &n_block);
	} else if (cdb[0] == VERIFY_16) {
		if (scmd->cmd_len < 16)
			goto invalid_fld;
		scsi_16_lba_len(cdb, &block, &n_block);
	} else
		goto invalid_fld;

	if (!n_block)
		goto nothing_to_do;
	if (block >= dev_sectors)
		goto out_of_range;
	if ((block + n_block) > dev_sectors)
		goto out_of_range;

	if (dev->flags & ATA_DFLAG_LBA) {
		tf->flags |= ATA_TFLAG_LBA;

		if (lba_28_ok(block, n_block)) {
			/* use LBA28 */
			tf->command = ATA_CMD_VERIFY;
			tf->device |= (block >> 24) & 0xf;
		} else if (lba_48_ok(block, n_block)) {
			if (!(dev->flags & ATA_DFLAG_LBA48))
				goto out_of_range;

			/* use LBA48 */
			tf->flags |= ATA_TFLAG_LBA48;
			tf->command = ATA_CMD_VERIFY_EXT;

			tf->hob_nsect = (n_block >> 8) & 0xff;

			tf->hob_lbah = (block >> 40) & 0xff;
			tf->hob_lbam = (block >> 32) & 0xff;
			tf->hob_lbal = (block >> 24) & 0xff;
		} else
			/* request too large even for LBA48 */
			goto out_of_range;

		tf->nsect = n_block & 0xff;

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

		tf->device |= ATA_LBA;
	} else {
		/* CHS */
		u32 sect, head, cyl, track;

		if (!lba_28_ok(block, n_block))
			goto out_of_range;

		/* Convert LBA to CHS */
		track = (u32)block / dev->sectors;
		cyl   = track / dev->heads;
		head  = track % dev->heads;
		sect  = (u32)block % dev->sectors + 1;

		DPRINTK("block %u track %u cyl %u head %u sect %u\n",
			(u32)block, track, cyl, head, sect);

		/* Check whether the converted CHS can fit.
		   Cylinder: 0-65535
		   Head: 0-15
		   Sector: 1-255*/
		if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect))
			goto out_of_range;

		tf->command = ATA_CMD_VERIFY;
		tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
		tf->lbal = sect;
		tf->lbam = cyl;
		tf->lbah = cyl >> 8;
		tf->device |= head;
	}

	return 0;

invalid_fld:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x0);
	/* "Invalid field in cbd" */
	return 1;

out_of_range:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x21, 0x0);
	/* "Logical Block Address out of range" */
	return 1;

nothing_to_do:
	scmd->result = SAM_STAT_GOOD;
	return 1;
}

/**
 *	ata_scsi_rw_xlat - Translate SCSI r/w command into an ATA one
 *	@qc: Storage for translated ATA taskfile
 *
 *	Converts any of six SCSI read/write commands into the
 *	ATA counterpart, including starting sector (LBA),
 *	sector count, and taking into account the device's LBA48
 *	support.
 *
 *	Commands %READ_6, %READ_10, %READ_16, %WRITE_6, %WRITE_10, and
 *	%WRITE_16 are currently supported.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	Zero on success, non-zero on error.
 */
static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
{
	struct scsi_cmnd *scmd = qc->scsicmd;
	const u8 *cdb = scmd->cmnd;
	unsigned int tf_flags = 0;
	u64 block;
	u32 n_block;
	int rc;

	if (cdb[0] == WRITE_10 || cdb[0] == WRITE_6 || cdb[0] == WRITE_16)
		tf_flags |= ATA_TFLAG_WRITE;

	/* Calculate the SCSI LBA, transfer length and FUA. */
	switch (cdb[0]) {
	case READ_10:
	case WRITE_10:
		if (unlikely(scmd->cmd_len < 10))
			goto invalid_fld;
		scsi_10_lba_len(cdb, &block, &n_block);
		if (unlikely(cdb[1] & (1 << 3)))
			tf_flags |= ATA_TFLAG_FUA;
		break;
	case READ_6:
	case WRITE_6:
		if (unlikely(scmd->cmd_len < 6))
			goto invalid_fld;
		scsi_6_lba_len(cdb, &block, &n_block);

		/* for 6-byte r/w commands, transfer length 0
		 * means 256 blocks of data, not 0 block.
		 */
		if (!n_block)
			n_block = 256;
		break;
	case READ_16:
	case WRITE_16:
		if (unlikely(scmd->cmd_len < 16))
			goto invalid_fld;
		scsi_16_lba_len(cdb, &block, &n_block);
		if (unlikely(cdb[1] & (1 << 3)))
			tf_flags |= ATA_TFLAG_FUA;
		break;
	default:
		DPRINTK("no-byte command\n");
		goto invalid_fld;
	}

	/* Check and compose ATA command */
	if (!n_block)
		/* For 10-byte and 16-byte SCSI R/W commands, transfer
		 * length 0 means transfer 0 block of data.
		 * However, for ATA R/W commands, sector count 0 means
		 * 256 or 65536 sectors, not 0 sectors as in SCSI.
		 *
		 * WARNING: one or two older ATA drives treat 0 as 0...
		 */
		goto nothing_to_do;

	qc->flags |= ATA_QCFLAG_IO;
	qc->nbytes = n_block * ATA_SECT_SIZE;

	rc = ata_build_rw_tf(&qc->tf, qc->dev, block, n_block, tf_flags,
			     qc->tag);
	if (likely(rc == 0))
		return 0;

	if (rc == -ERANGE)
		goto out_of_range;
	/* treat all other errors as -EINVAL, fall through */
invalid_fld:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x24, 0x0);
	/* "Invalid field in cbd" */
	return 1;

out_of_range:
	ata_scsi_set_sense(scmd, ILLEGAL_REQUEST, 0x21, 0x0);
	/* "Logical Block Address out of range" */
	return 1;

nothing_to_do:
	scmd->result = SAM_STAT_GOOD;
	return 1;
}

static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct scsi_cmnd *cmd = qc->scsicmd;
	u8 *cdb = cmd->cmnd;
	int need_sense = (qc->err_mask != 0);

	/* For ATA pass thru (SAT) commands, generate a sense block if
	 * user mandated it or if there's an error.  Note that if we
	 * generate because the user forced us to, a check condition
	 * is generated and the ATA register values are returned
	 * whether the command completed successfully or not. If there
	 * was no error, SK, ASC and ASCQ will all be zero.
	 */
	if (((cdb[0] == ATA_16) || (cdb[0] == ATA_12)) &&
	    ((cdb[2] & 0x20) || need_sense)) {
		ata_gen_passthru_sense(qc);
	} else {
		if (!need_sense) {
			cmd->result = SAM_STAT_GOOD;
		} else {
			/* TODO: decide which descriptor format to use
			 * for 48b LBA devices and call that here
			 * instead of the fixed desc, which is only
			 * good for smaller LBA (and maybe CHS?)
			 * devices.
			 */
			ata_gen_ata_sense(qc);
		}
	}

	/* XXX: track spindown state for spindown skipping and warning */
	if (unlikely(qc->tf.command == ATA_CMD_STANDBY ||
		     qc->tf.command == ATA_CMD_STANDBYNOW1))
		qc->dev->flags |= ATA_DFLAG_SPUNDOWN;
	else if (likely(system_state != SYSTEM_HALT &&
			system_state != SYSTEM_POWER_OFF))
		qc->dev->flags &= ~ATA_DFLAG_SPUNDOWN;

	if (need_sense && !ap->ops->error_handler)
		ata_dump_status(ap->print_id, &qc->result_tf);

	qc->scsidone(cmd);

	ata_qc_free(qc);
}

/**
 *	ata_scsi_translate - Translate then issue SCSI command to ATA device
 *	@dev: ATA device to which the command is addressed
 *	@cmd: SCSI command to execute
 *	@done: SCSI command completion function
 *	@xlat_func: Actor which translates @cmd to an ATA taskfile
 *
 *	Our ->queuecommand() function has decided that the SCSI
 *	command issued can be directly translated into an ATA
 *	command, rather than handled internally.
 *
 *	This function sets up an ata_queued_cmd structure for the
 *	SCSI command, and sends that ata_queued_cmd to the hardware.
 *
 *	The xlat_func argument (actor) returns 0 if ready to execute
 *	ATA command, else 1 to finish translation. If 1 is returned
 *	then cmd->result (and possibly cmd->sense_buffer) are assumed
 *	to be set reflecting an error condition or clean (early)