scsi_transport_spi.c

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	return retval;
}

static CLASS_DEVICE_ATTR(period, S_IRUGO | S_IWUSR, 
			 show_spi_transport_period,
			 store_spi_transport_period);

static ssize_t
show_spi_transport_min_period(struct class_device *cdev, char *buf)
{
	struct scsi_target *starget = transport_class_to_starget(cdev);
	struct spi_transport_attrs *tp =
		(struct spi_transport_attrs *)&starget->starget_data;

	return show_spi_transport_period_helper(buf, tp->min_period);
}

static ssize_t
store_spi_transport_min_period(struct class_device *cdev, const char *buf,
			    size_t count)
{
	struct scsi_target *starget = transport_class_to_starget(cdev);
	struct spi_transport_attrs *tp =
		(struct spi_transport_attrs *)&starget->starget_data;

	return store_spi_transport_period_helper(cdev, buf, count,
						 &tp->min_period);
}


static CLASS_DEVICE_ATTR(min_period, S_IRUGO | S_IWUSR, 
			 show_spi_transport_min_period,
			 store_spi_transport_min_period);


static ssize_t show_spi_host_signalling(struct class_device *cdev, char *buf)
{
	struct Scsi_Host *shost = transport_class_to_shost(cdev);
	struct spi_internal *i = to_spi_internal(shost->transportt);

	if (i->f->get_signalling)
		i->f->get_signalling(shost);

	return sprintf(buf, "%s\n", spi_signal_to_string(spi_signalling(shost)));
}
static ssize_t store_spi_host_signalling(struct class_device *cdev,
					 const char *buf, size_t count)
{
	struct Scsi_Host *shost = transport_class_to_shost(cdev);
	struct spi_internal *i = to_spi_internal(shost->transportt);
	enum spi_signal_type type = spi_signal_to_value(buf);

	if (type != SPI_SIGNAL_UNKNOWN)
		i->f->set_signalling(shost, type);

	return count;
}
static CLASS_DEVICE_ATTR(signalling, S_IRUGO | S_IWUSR,
			 show_spi_host_signalling,
			 store_spi_host_signalling);

#define DV_SET(x, y)			\
	if(i->f->set_##x)		\
		i->f->set_##x(sdev->sdev_target, y)

enum spi_compare_returns {
	SPI_COMPARE_SUCCESS,
	SPI_COMPARE_FAILURE,
	SPI_COMPARE_SKIP_TEST,
};


/* This is for read/write Domain Validation:  If the device supports
 * an echo buffer, we do read/write tests to it */
static enum spi_compare_returns
spi_dv_device_echo_buffer(struct scsi_device *sdev, u8 *buffer,
			  u8 *ptr, const int retries)
{
	int len = ptr - buffer;
	int j, k, r, result;
	unsigned int pattern = 0x0000ffff;
	struct scsi_sense_hdr sshdr;

	const char spi_write_buffer[] = {
		WRITE_BUFFER, 0x0a, 0, 0, 0, 0, 0, len >> 8, len & 0xff, 0
	};
	const char spi_read_buffer[] = {
		READ_BUFFER, 0x0a, 0, 0, 0, 0, 0, len >> 8, len & 0xff, 0
	};

	/* set up the pattern buffer.  Doesn't matter if we spill
	 * slightly beyond since that's where the read buffer is */
	for (j = 0; j < len; ) {

		/* fill the buffer with counting (test a) */
		for ( ; j < min(len, 32); j++)
			buffer[j] = j;
		k = j;
		/* fill the buffer with alternating words of 0x0 and
		 * 0xffff (test b) */
		for ( ; j < min(len, k + 32); j += 2) {
			u16 *word = (u16 *)&buffer[j];
			
			*word = (j & 0x02) ? 0x0000 : 0xffff;
		}
		k = j;
		/* fill with crosstalk (alternating 0x5555 0xaaa)
                 * (test c) */
		for ( ; j < min(len, k + 32); j += 2) {
			u16 *word = (u16 *)&buffer[j];

			*word = (j & 0x02) ? 0x5555 : 0xaaaa;
		}
		k = j;
		/* fill with shifting bits (test d) */
		for ( ; j < min(len, k + 32); j += 4) {
			u32 *word = (unsigned int *)&buffer[j];
			u32 roll = (pattern & 0x80000000) ? 1 : 0;
			
			*word = pattern;
			pattern = (pattern << 1) | roll;
		}
		/* don't bother with random data (test e) */
	}

	for (r = 0; r < retries; r++) {
		result = spi_execute(sdev, spi_write_buffer, DMA_TO_DEVICE,
				     buffer, len, &sshdr);
		if(result || !scsi_device_online(sdev)) {

			scsi_device_set_state(sdev, SDEV_QUIESCE);
			if (scsi_sense_valid(&sshdr)
			    && sshdr.sense_key == ILLEGAL_REQUEST
			    /* INVALID FIELD IN CDB */
			    && sshdr.asc == 0x24 && sshdr.ascq == 0x00)
				/* This would mean that the drive lied
				 * to us about supporting an echo
				 * buffer (unfortunately some Western
				 * Digital drives do precisely this)
				 */
				return SPI_COMPARE_SKIP_TEST;


			sdev_printk(KERN_ERR, sdev, "Write Buffer failure %x\n", result);
			return SPI_COMPARE_FAILURE;
		}

		memset(ptr, 0, len);
		spi_execute(sdev, spi_read_buffer, DMA_FROM_DEVICE,
			    ptr, len, NULL);
		scsi_device_set_state(sdev, SDEV_QUIESCE);

		if (memcmp(buffer, ptr, len) != 0)
			return SPI_COMPARE_FAILURE;
	}
	return SPI_COMPARE_SUCCESS;
}

/* This is for the simplest form of Domain Validation: a read test
 * on the inquiry data from the device */
static enum spi_compare_returns
spi_dv_device_compare_inquiry(struct scsi_device *sdev, u8 *buffer,
			      u8 *ptr, const int retries)
{
	int r, result;
	const int len = sdev->inquiry_len;
	const char spi_inquiry[] = {
		INQUIRY, 0, 0, 0, len, 0
	};

	for (r = 0; r < retries; r++) {
		memset(ptr, 0, len);

		result = spi_execute(sdev, spi_inquiry, DMA_FROM_DEVICE,
				     ptr, len, NULL);
		
		if(result || !scsi_device_online(sdev)) {
			scsi_device_set_state(sdev, SDEV_QUIESCE);
			return SPI_COMPARE_FAILURE;
		}

		/* If we don't have the inquiry data already, the
		 * first read gets it */
		if (ptr == buffer) {
			ptr += len;
			--r;
			continue;
		}

		if (memcmp(buffer, ptr, len) != 0)
			/* failure */
			return SPI_COMPARE_FAILURE;
	}
	return SPI_COMPARE_SUCCESS;
}

static enum spi_compare_returns
spi_dv_retrain(struct scsi_device *sdev, u8 *buffer, u8 *ptr,
	       enum spi_compare_returns 
	       (*compare_fn)(struct scsi_device *, u8 *, u8 *, int))
{
	struct spi_internal *i = to_spi_internal(sdev->host->transportt);
	struct scsi_target *starget = sdev->sdev_target;
	int period = 0, prevperiod = 0; 
	enum spi_compare_returns retval;


	for (;;) {
		int newperiod;
		retval = compare_fn(sdev, buffer, ptr, DV_LOOPS);

		if (retval == SPI_COMPARE_SUCCESS
		    || retval == SPI_COMPARE_SKIP_TEST)
			break;

		/* OK, retrain, fallback */
		if (i->f->get_iu)
			i->f->get_iu(starget);
		if (i->f->get_qas)
			i->f->get_qas(starget);
		if (i->f->get_period)
			i->f->get_period(sdev->sdev_target);

		/* Here's the fallback sequence; first try turning off
		 * IU, then QAS (if we can control them), then finally
		 * fall down the periods */
		if (i->f->set_iu && spi_iu(starget)) {
			starget_printk(KERN_ERR, starget, "Domain Validation Disabing Information Units\n");
			DV_SET(iu, 0);
		} else if (i->f->set_qas && spi_qas(starget)) {
			starget_printk(KERN_ERR, starget, "Domain Validation Disabing Quick Arbitration and Selection\n");
			DV_SET(qas, 0);
		} else {
			newperiod = spi_period(starget);
			period = newperiod > period ? newperiod : period;
			if (period < 0x0d)
				period++;
			else
				period += period >> 1;

			if (unlikely(period > 0xff || period == prevperiod)) {
				/* Total failure; set to async and return */
				starget_printk(KERN_ERR, starget, "Domain Validation Failure, dropping back to Asynchronous\n");
				DV_SET(offset, 0);
				return SPI_COMPARE_FAILURE;
			}
			starget_printk(KERN_ERR, starget, "Domain Validation detected failure, dropping back\n");
			DV_SET(period, period);
			prevperiod = period;
		}
	}
	return retval;
}

static int
spi_dv_device_get_echo_buffer(struct scsi_device *sdev, u8 *buffer)
{
	int l, result;

	/* first off do a test unit ready.  This can error out 
	 * because of reservations or some other reason.  If it
	 * fails, the device won't let us write to the echo buffer
	 * so just return failure */
	
	const char spi_test_unit_ready[] = {
		TEST_UNIT_READY, 0, 0, 0, 0, 0
	};

	const char spi_read_buffer_descriptor[] = {
		READ_BUFFER, 0x0b, 0, 0, 0, 0, 0, 0, 4, 0
	};

	
	/* We send a set of three TURs to clear any outstanding 
	 * unit attention conditions if they exist (Otherwise the
	 * buffer tests won't be happy).  If the TUR still fails
	 * (reservation conflict, device not ready, etc) just
	 * skip the write tests */
	for (l = 0; ; l++) {
		result = spi_execute(sdev, spi_test_unit_ready, DMA_NONE, 
				     NULL, 0, NULL);

		if(result) {
			if(l >= 3)
				return 0;
		} else {
			/* TUR succeeded */
			break;
		}
	}

	result = spi_execute(sdev, spi_read_buffer_descriptor, 
			     DMA_FROM_DEVICE, buffer, 4, NULL);

	if (result)
		/* Device has no echo buffer */
		return 0;

	return buffer[3] + ((buffer[2] & 0x1f) << 8);
}

static void
spi_dv_device_internal(struct scsi_device *sdev, u8 *buffer)
{
	struct spi_internal *i = to_spi_internal(sdev->host->transportt);
	struct scsi_target *starget = sdev->sdev_target;
	struct Scsi_Host *shost = sdev->host;
	int len = sdev->inquiry_len;
	int min_period = spi_min_period(starget);
	int max_width = spi_max_width(starget);
	/* first set us up for narrow async */
	DV_SET(offset, 0);
	DV_SET(width, 0);

	if (spi_dv_device_compare_inquiry(sdev, buffer, buffer, DV_LOOPS)
	    != SPI_COMPARE_SUCCESS) {
		starget_printk(KERN_ERR, starget, "Domain Validation Initial Inquiry Failed\n");
		/* FIXME: should probably offline the device here? */
		return;
	}

	if (!scsi_device_wide(sdev)) {
		spi_max_width(starget) = 0;
		max_width = 0;
	}

	/* test width */
	if (i->f->set_width && max_width) {
		i->f->set_width(starget, 1);

		if (spi_dv_device_compare_inquiry(sdev, buffer,
						   buffer + len,
						   DV_LOOPS)
		    != SPI_COMPARE_SUCCESS) {
			starget_printk(KERN_ERR, starget, "Wide Transfers Fail\n");
			i->f->set_width(starget, 0);
			/* Make sure we don't force wide back on by asking
			 * for a transfer period that requires it */
			max_width = 0;
			if (min_period < 10)
				min_period = 10;
		}
	}

	if (!i->f->set_period)
		return;

	/* device can't handle synchronous */
	if (!scsi_device_sync(sdev) && !scsi_device_dt(sdev))
		return;

	/* len == -1 is the signal that we need to ascertain the
	 * presence of an echo buffer before trying to use it.  len ==
	 * 0 means we don't have an echo buffer */
	len = -1;

 retry:

	/* now set up to the maximum */
	DV_SET(offset, spi_max_offset(starget));
	DV_SET(period, min_period);

	/* try QAS requests; this should be harmless to set if the
	 * target supports it */
	if (scsi_device_qas(sdev)) {
		DV_SET(qas, 1);
	} else {
		DV_SET(qas, 0);
	}

	if (scsi_device_ius(sdev) && min_period < 9) {
		/* This u320 (or u640). Set IU transfers */
		DV_SET(iu, 1);
		/* Then set the optional parameters */
		DV_SET(rd_strm, 1);
		DV_SET(wr_flow, 1);
		DV_SET(rti, 1);
		if (min_period == 8)
			DV_SET(pcomp_en, 1);
	} else {
		DV_SET(iu, 0);
	}

	/* now that we've done all this, actually check the bus
	 * signal type (if known).  Some devices are stupid on
	 * a SE bus and still claim they can try LVD only settings */
	if (i->f->get_signalling)
		i->f->get_signalling(shost);
	if (spi_signalling(shost) == SPI_SIGNAL_SE ||
	    spi_signalling(shost) == SPI_SIGNAL_HVD ||
	    !scsi_device_dt(sdev)) {
		DV_SET(dt, 0);
	} else {
		DV_SET(dt, 1);
	}
	/* set width last because it will pull all the other
	 * parameters down to required values */
	DV_SET(width, max_width);

	/* Do the read only INQUIRY tests */
	spi_dv_retrain(sdev, buffer, buffer + sdev->inquiry_len,
		       spi_dv_device_compare_inquiry);
	/* See if we actually managed to negotiate and sustain DT */
	if (i->f->get_dt)
		i->f->get_dt(starget);

	/* see if the device has an echo buffer.  If it does we can do
	 * the SPI pattern write tests.  Because of some broken
	 * devices, we *only* try this on a device that has actually
	 * negotiated DT */

	if (len == -1 && spi_dt(starget))
		len = spi_dv_device_get_echo_buffer(sdev, buffer);

	if (len <= 0) {
		starget_printk(KERN_INFO, starget, "Domain Validation skipping write tests\n");
		return;
	}

	if (len > SPI_MAX_ECHO_BUFFER_SIZE) {
		starget_printk(KERN_WARNING, starget, "Echo buffer size %d is too big, trimming to %d\n", len, SPI_MAX_ECHO_BUFFER_SIZE);
		len = SPI_MAX_ECHO_BUFFER_SIZE;
	}

	if (spi_dv_retrain(sdev, buffer, buffer + len,
			   spi_dv_device_echo_buffer)
	    == SPI_COMPARE_SKIP_TEST) {
		/* OK, the stupid drive can't do a write echo buffer
		 * test after all, fall back to the read tests */
		len = 0;
		goto retry;
	}
}


/**	spi_dv_device - Do Domain Validation on the device
 *	@sdev:		scsi device to validate
 *
 *	Performs the domain validation on the given device in the
 *	current execution thread.  Since DV operations may sleep,
 *	the current thread must have user context.  Also no SCSI
 *	related locks that would deadlock I/O issued by the DV may
 *	be held.
 */
void
spi_dv_device(struct scsi_device *sdev)
{
	struct scsi_target *starget = sdev->sdev_target;
	u8 *buffer;
	const int len = SPI_MAX_ECHO_BUFFER_SIZE*2;

	if (unlikely(scsi_device_get(sdev)))
		return;

	if (unlikely(spi_dv_in_progress(starget)))
		return;
	spi_dv_in_progress(starget) = 1;

	buffer = kzalloc(len, GFP_KERNEL);

	if (unlikely(!buffer))
		goto out_put;

	/* We need to verify that the actual device will quiesce; the
	 * later target quiesce is just a nice to have */
	if (unlikely(scsi_device_quiesce(sdev)))
		goto out_free;

	scsi_target_quiesce(starget);

	spi_dv_pending(starget) = 1;
	mutex_lock(&spi_dv_mutex(starget));

	starget_printk(KERN_INFO, starget, "Beginning Domain Validation\n");

	spi_dv_device_internal(sdev, buffer);

	starget_printk(KERN_INFO, starget, "Ending Domain Validation\n");

	mutex_unlock(&spi_dv_mutex(starget));
	spi_dv_pending(starget) = 0;