scsi_transport_spi.c

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/* 
 *  Parallel SCSI (SPI) transport specific attributes exported to sysfs.
 *
 *  Copyright (c) 2003 Silicon Graphics, Inc.  All rights reserved.
 *  Copyright (c) 2004, 2005 James Bottomley <[e-mail]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/workqueue.h>
#include <linux/blkdev.h>
#include <linux/mutex.h>
#include <scsi/scsi.h>
#include "scsi_priv.h"
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_spi.h>

#define SPI_NUM_ATTRS 14	/* increase this if you add attributes */
#define SPI_OTHER_ATTRS 1	/* Increase this if you add "always
				 * on" attributes */
#define SPI_HOST_ATTRS	1

#define SPI_MAX_ECHO_BUFFER_SIZE	4096

#define DV_LOOPS	3
#define DV_TIMEOUT	(10*HZ)
#define DV_RETRIES	3	/* should only need at most 
				 * two cc/ua clears */

/* Private data accessors (keep these out of the header file) */
#define spi_dv_in_progress(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_in_progress)
#define spi_dv_mutex(x) (((struct spi_transport_attrs *)&(x)->starget_data)->dv_mutex)

struct spi_internal {
	struct scsi_transport_template t;
	struct spi_function_template *f;
	/* The actual attributes */
	struct class_device_attribute private_attrs[SPI_NUM_ATTRS];
	/* The array of null terminated pointers to attributes 
	 * needed by scsi_sysfs.c */
	struct class_device_attribute *attrs[SPI_NUM_ATTRS + SPI_OTHER_ATTRS + 1];
	struct class_device_attribute private_host_attrs[SPI_HOST_ATTRS];
	struct class_device_attribute *host_attrs[SPI_HOST_ATTRS + 1];
};

#define to_spi_internal(tmpl)	container_of(tmpl, struct spi_internal, t)

static const int ppr_to_ps[] = {
	/* The PPR values 0-6 are reserved, fill them in when
	 * the committee defines them */
	-1,			/* 0x00 */
	-1,			/* 0x01 */
	-1,			/* 0x02 */
	-1,			/* 0x03 */
	-1,			/* 0x04 */
	-1,			/* 0x05 */
	-1,			/* 0x06 */
	 3125,			/* 0x07 */
	 6250,			/* 0x08 */
	12500,			/* 0x09 */
	25000,			/* 0x0a */
	30300,			/* 0x0b */
	50000,			/* 0x0c */
};
/* The PPR values at which you calculate the period in ns by multiplying
 * by 4 */
#define SPI_STATIC_PPR	0x0c

static int sprint_frac(char *dest, int value, int denom)
{
	int frac = value % denom;
	int result = sprintf(dest, "%d", value / denom);

	if (frac == 0)
		return result;
	dest[result++] = '.';

	do {
		denom /= 10;
		sprintf(dest + result, "%d", frac / denom);
		result++;
		frac %= denom;
	} while (frac);

	dest[result++] = '\0';
	return result;
}

static int spi_execute(struct scsi_device *sdev, const void *cmd,
		       enum dma_data_direction dir,
		       void *buffer, unsigned bufflen,
		       struct scsi_sense_hdr *sshdr)
{
	int i, result;
	unsigned char sense[SCSI_SENSE_BUFFERSIZE];

	for(i = 0; i < DV_RETRIES; i++) {
		result = scsi_execute(sdev, cmd, dir, buffer, bufflen,
				      sense, DV_TIMEOUT, /* retries */ 1,
				      REQ_FAILFAST);
		if (result & DRIVER_SENSE) {
			struct scsi_sense_hdr sshdr_tmp;
			if (!sshdr)
				sshdr = &sshdr_tmp;

			if (scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE,
						 sshdr)
			    && sshdr->sense_key == UNIT_ATTENTION)
				continue;
		}
		break;
	}
	return result;
}

static struct {
	enum spi_signal_type	value;
	char			*name;
} signal_types[] = {
	{ SPI_SIGNAL_UNKNOWN, "unknown" },
	{ SPI_SIGNAL_SE, "SE" },
	{ SPI_SIGNAL_LVD, "LVD" },
	{ SPI_SIGNAL_HVD, "HVD" },
};

static inline const char *spi_signal_to_string(enum spi_signal_type type)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(signal_types); i++) {
		if (type == signal_types[i].value)
			return signal_types[i].name;
	}
	return NULL;
}
static inline enum spi_signal_type spi_signal_to_value(const char *name)
{
	int i, len;

	for (i = 0; i < ARRAY_SIZE(signal_types); i++) {
		len =  strlen(signal_types[i].name);
		if (strncmp(name, signal_types[i].name, len) == 0 &&
		    (name[len] == '\n' || name[len] == '\0'))
			return signal_types[i].value;
	}
	return SPI_SIGNAL_UNKNOWN;
}

static int spi_host_setup(struct transport_container *tc, struct device *dev,
			  struct class_device *cdev)
{
	struct Scsi_Host *shost = dev_to_shost(dev);

	spi_signalling(shost) = SPI_SIGNAL_UNKNOWN;

	return 0;
}

static DECLARE_TRANSPORT_CLASS(spi_host_class,
			       "spi_host",
			       spi_host_setup,
			       NULL,
			       NULL);

static int spi_host_match(struct attribute_container *cont,
			  struct device *dev)
{
	struct Scsi_Host *shost;
	struct spi_internal *i;

	if (!scsi_is_host_device(dev))
		return 0;

	shost = dev_to_shost(dev);
	if (!shost->transportt  || shost->transportt->host_attrs.ac.class
	    != &spi_host_class.class)
		return 0;

	i = to_spi_internal(shost->transportt);
	
	return &i->t.host_attrs.ac == cont;
}

static int spi_device_configure(struct transport_container *tc,
				struct device *dev,
				struct class_device *cdev)
{
	struct scsi_device *sdev = to_scsi_device(dev);
	struct scsi_target *starget = sdev->sdev_target;

	/* Populate the target capability fields with the values
	 * gleaned from the device inquiry */

	spi_support_sync(starget) = scsi_device_sync(sdev);
	spi_support_wide(starget) = scsi_device_wide(sdev);
	spi_support_dt(starget) = scsi_device_dt(sdev);
	spi_support_dt_only(starget) = scsi_device_dt_only(sdev);
	spi_support_ius(starget) = scsi_device_ius(sdev);
	spi_support_qas(starget) = scsi_device_qas(sdev);

	return 0;
}

static int spi_setup_transport_attrs(struct transport_container *tc,
				     struct device *dev,
				     struct class_device *cdev)
{
	struct scsi_target *starget = to_scsi_target(dev);

	spi_period(starget) = -1;	/* illegal value */
	spi_min_period(starget) = 0;
	spi_offset(starget) = 0;	/* async */
	spi_max_offset(starget) = 255;
	spi_width(starget) = 0;	/* narrow */
	spi_max_width(starget) = 1;
	spi_iu(starget) = 0;	/* no IU */
	spi_dt(starget) = 0;	/* ST */
	spi_qas(starget) = 0;
	spi_wr_flow(starget) = 0;
	spi_rd_strm(starget) = 0;
	spi_rti(starget) = 0;
	spi_pcomp_en(starget) = 0;
	spi_hold_mcs(starget) = 0;
	spi_dv_pending(starget) = 0;
	spi_dv_in_progress(starget) = 0;
	spi_initial_dv(starget) = 0;
	mutex_init(&spi_dv_mutex(starget));

	return 0;
}

#define spi_transport_show_simple(field, format_string)			\
									\
static ssize_t								\
show_spi_transport_##field(struct class_device *cdev, char *buf)	\
{									\
	struct scsi_target *starget = transport_class_to_starget(cdev);	\
	struct spi_transport_attrs *tp;					\
									\
	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
	return snprintf(buf, 20, format_string, tp->field);		\
}

#define spi_transport_store_simple(field, format_string)		\
									\
static ssize_t								\
store_spi_transport_##field(struct class_device *cdev, const char *buf, \
			    size_t count)				\
{									\
	int val;							\
	struct scsi_target *starget = transport_class_to_starget(cdev);	\
	struct spi_transport_attrs *tp;					\
									\
	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
	val = simple_strtoul(buf, NULL, 0);				\
	tp->field = val;						\
	return count;							\
}

#define spi_transport_show_function(field, format_string)		\
									\
static ssize_t								\
show_spi_transport_##field(struct class_device *cdev, char *buf)	\
{									\
	struct scsi_target *starget = transport_class_to_starget(cdev);	\
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
	struct spi_transport_attrs *tp;					\
	struct spi_internal *i = to_spi_internal(shost->transportt);	\
	tp = (struct spi_transport_attrs *)&starget->starget_data;	\
	if (i->f->get_##field)						\
		i->f->get_##field(starget);				\
	return snprintf(buf, 20, format_string, tp->field);		\
}

#define spi_transport_store_function(field, format_string)		\
static ssize_t								\
store_spi_transport_##field(struct class_device *cdev, const char *buf, \
			    size_t count)				\
{									\
	int val;							\
	struct scsi_target *starget = transport_class_to_starget(cdev);	\
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
	struct spi_internal *i = to_spi_internal(shost->transportt);	\
									\
	val = simple_strtoul(buf, NULL, 0);				\
	i->f->set_##field(starget, val);			\
	return count;							\
}

#define spi_transport_store_max(field, format_string)			\
static ssize_t								\
store_spi_transport_##field(struct class_device *cdev, const char *buf, \
			    size_t count)				\
{									\
	int val;							\
	struct scsi_target *starget = transport_class_to_starget(cdev);	\
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);	\
	struct spi_internal *i = to_spi_internal(shost->transportt);	\
	struct spi_transport_attrs *tp					\
		= (struct spi_transport_attrs *)&starget->starget_data;	\
									\
	val = simple_strtoul(buf, NULL, 0);				\
	if (val > tp->max_##field)					\
		val = tp->max_##field;					\
	i->f->set_##field(starget, val);				\
	return count;							\
}

#define spi_transport_rd_attr(field, format_string)			\
	spi_transport_show_function(field, format_string)		\
	spi_transport_store_function(field, format_string)		\
static CLASS_DEVICE_ATTR(field, S_IRUGO | S_IWUSR,			\
			 show_spi_transport_##field,			\
			 store_spi_transport_##field);

#define spi_transport_simple_attr(field, format_string)			\
	spi_transport_show_simple(field, format_string)			\
	spi_transport_store_simple(field, format_string)		\
static CLASS_DEVICE_ATTR(field, S_IRUGO | S_IWUSR,			\
			 show_spi_transport_##field,			\
			 store_spi_transport_##field);

#define spi_transport_max_attr(field, format_string)			\
	spi_transport_show_function(field, format_string)		\
	spi_transport_store_max(field, format_string)			\
	spi_transport_simple_attr(max_##field, format_string)		\
static CLASS_DEVICE_ATTR(field, S_IRUGO | S_IWUSR,			\
			 show_spi_transport_##field,			\
			 store_spi_transport_##field);

/* The Parallel SCSI Tranport Attributes: */
spi_transport_max_attr(offset, "%d\n");
spi_transport_max_attr(width, "%d\n");
spi_transport_rd_attr(iu, "%d\n");
spi_transport_rd_attr(dt, "%d\n");
spi_transport_rd_attr(qas, "%d\n");
spi_transport_rd_attr(wr_flow, "%d\n");
spi_transport_rd_attr(rd_strm, "%d\n");
spi_transport_rd_attr(rti, "%d\n");
spi_transport_rd_attr(pcomp_en, "%d\n");
spi_transport_rd_attr(hold_mcs, "%d\n");

/* we only care about the first child device so we return 1 */
static int child_iter(struct device *dev, void *data)
{
	struct scsi_device *sdev = to_scsi_device(dev);

	spi_dv_device(sdev);
	return 1;
}

static ssize_t
store_spi_revalidate(struct class_device *cdev, const char *buf, size_t count)
{
	struct scsi_target *starget = transport_class_to_starget(cdev);

	device_for_each_child(&starget->dev, NULL, child_iter);
	return count;
}
static CLASS_DEVICE_ATTR(revalidate, S_IWUSR, NULL, store_spi_revalidate);

/* Translate the period into ns according to the current spec
 * for SDTR/PPR messages */
static int period_to_str(char *buf, int period)
{
	int len, picosec;

	if (period < 0 || period > 0xff) {
		picosec = -1;
	} else if (period <= SPI_STATIC_PPR) {
		picosec = ppr_to_ps[period];
	} else {
		picosec = period * 4000;
	}

	if (picosec == -1) {
		len = sprintf(buf, "reserved");
	} else {
		len = sprint_frac(buf, picosec, 1000);
	}

	return len;
}

static ssize_t
show_spi_transport_period_helper(char *buf, int period)
{
	int len = period_to_str(buf, period);
	buf[len++] = '\n';
	buf[len] = '\0';
	return len;
}

static ssize_t
store_spi_transport_period_helper(struct class_device *cdev, const char *buf,
				  size_t count, int *periodp)
{
	int j, picosec, period = -1;
	char *endp;

	picosec = simple_strtoul(buf, &endp, 10) * 1000;
	if (*endp == '.') {
		int mult = 100;
		do {
			endp++;
			if (!isdigit(*endp))
				break;
			picosec += (*endp - '0') * mult;
			mult /= 10;
		} while (mult > 0);
	}

	for (j = 0; j <= SPI_STATIC_PPR; j++) {
		if (ppr_to_ps[j] < picosec)
			continue;
		period = j;
		break;
	}

	if (period == -1)
		period = picosec / 4000;

	if (period > 0xff)
		period = 0xff;

	*periodp = period;

	return count;
}

static ssize_t
show_spi_transport_period(struct class_device *cdev, char *buf)
{
	struct scsi_target *starget = transport_class_to_starget(cdev);
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
	struct spi_internal *i = to_spi_internal(shost->transportt);
	struct spi_transport_attrs *tp =
		(struct spi_transport_attrs *)&starget->starget_data;

	if (i->f->get_period)
		i->f->get_period(starget);

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

static ssize_t
store_spi_transport_period(struct class_device *cdev, const char *buf,
			    size_t count)
{
	struct scsi_target *starget = transport_class_to_starget(cdev);
	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
	struct spi_internal *i = to_spi_internal(shost->transportt);
	struct spi_transport_attrs *tp =
		(struct spi_transport_attrs *)&starget->starget_data;
	int period, retval;

	retval = store_spi_transport_period_helper(cdev, buf, count, &period);

	if (period < tp->min_period)
		period = tp->min_period;

	i->f->set_period(starget, period);