/* Driver for USB Mass Storage compliant devices
* SCSI layer glue code
*
* $Id: scsiglue.c,v 1.26 2002/04/22 03:39:43 mdharm Exp $
*
* Current development and maintenance by:
* (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
*
* Developed with the assistance of:
* (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
* (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
*
* Initial work by:
* (c) 1999 Michael Gee (michael@linuxspecific.com)
*
* This driver is based on the 'USB Mass Storage Class' document. This
* describes in detail the protocol used to communicate with such
* devices. Clearly, the designers had SCSI and ATAPI commands in
* mind when they created this document. The commands are all very
* similar to commands in the SCSI-II and ATAPI specifications.
*
* It is important to note that in a number of cases this class
* exhibits class-specific exemptions from the USB specification.
* Notably the usage of NAK, STALL and ACK differs from the norm, in
* that they are used to communicate wait, failed and OK on commands.
*
* Also, for certain devices, the interrupt endpoint is used to convey
* status of a command.
*
* Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
* information about this driver.
*
* 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, 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.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_devinfo.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include "usb.h"
#include "scsiglue.h"
#include "debug.h"
#include "transport.h"
#include "protocol.h"
/***********************************************************************
* Host functions
***********************************************************************/
static const char* host_info(struct Scsi_Host *host)
{
return "SCSI emulation for USB Mass Storage devices";
}
static int slave_alloc (struct scsi_device *sdev)
{
/*
* Set the INQUIRY transfer length to 36. We don't use any of
* the extra data and many devices choke if asked for more or
* less than 36 bytes.
*/
sdev->inquiry_len = 36;
return 0;
}
static int slave_configure(struct scsi_device *sdev)
{
struct us_data *us = host_to_us(sdev->host);
/* Scatter-gather buffers (all but the last) must have a length
* divisible by the bulk maxpacket size. Otherwise a data packet
* would end up being short, causing a premature end to the data
* transfer. Since high-speed bulk pipes have a maxpacket size
* of 512, we'll use that as the scsi device queue's DMA alignment
* mask. Guaranteeing proper alignment of the first buffer will
* have the desired effect because, except at the beginning and
* the end, scatter-gather buffers follow page boundaries. */
blk_queue_dma_alignment(sdev->request_queue, (512 - 1));
/* Set the SCSI level to at least 2. We'll leave it at 3 if that's
* what is originally reported. We need this to avoid confusing
* the SCSI layer with devices that report 0 or 1, but need 10-byte
* commands (ala ATAPI devices behind certain bridges, or devices
* which simply have broken INQUIRY data).
*
* NOTE: This means /dev/sg programs (ala cdrecord) will get the
* actual information. This seems to be the preference for
* programs like that.
*
* NOTE: This also means that /proc/scsi/scsi and sysfs may report
* the actual value or the modified one, depending on where the
* data comes from.
*/
if (sdev->scsi_level < SCSI_2)
sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2;
/* Many devices have trouble transfering more than 32KB at a time,
* while others have trouble with more than 64K. At this time we
* are limiting both to 32K (64 sectores).
*/
if ((us->flags & US_FL_MAX_SECTORS_64) &&
sdev->request_queue->max_sectors > 64)
blk_queue_max_sectors(sdev->request_queue, 64);
/* We can't put these settings in slave_alloc() because that gets
* called before the device type is known. Consequently these
* settings can't be overridden via the scsi devinfo mechanism. */
if (sdev->type == TYPE_DISK) {
/* Disk-type devices use MODE SENSE(6) if the protocol
* (SubClass) is Transparent SCSI, otherwise they use
* MODE SENSE(10). */
if (us->subclass != US_SC_SCSI)
sdev->use_10_for_ms = 1;
/* Many disks only accept MODE SENSE transfer lengths of
* 192 bytes (that's what Windows uses). */
sdev->use_192_bytes_for_3f = 1;
/* Some devices don't like MODE SENSE with page=0x3f,
* which is the command used for checking if a device
* is write-protected. Now that we tell the sd driver
* to do a 192-byte transfer with this command the
* majority of devices work fine, but a few still can't
* handle it. The sd driver will simply assume those
* devices are write-enabled. */
if (us->flags & US_FL_NO_WP_DETECT)
sdev->skip_ms_page_3f = 1;
/* A number of devices have problems with MODE SENSE for
* page x08, so we will skip it. */
sdev->skip_ms_page_8 = 1;
/* Some disks return the total number of blocks in response
* to READ CAPACITY rather than the highest block number.
* If this device makes that mistake, tell the sd driver. */
if (us->flags & US_FL_FIX_CAPACITY)
sdev->fix_capacity = 1;
/* Some devices report a SCSI revision level above 2 but are
* unable to handle the REPORT LUNS command (for which
* support is mandatory at level 3). Since we already have
* a Get-Max-LUN request, we won't lose much by setting the
* revision level down to 2. The only devices that would be
* affected are those with sparse LUNs. */
sdev->scsi_level = sdev->sdev_target->scsi_level = SCSI_2;
/* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
* Hardware Error) when any low-level error occurs,
* recoverable or not. Setting this flag tells the SCSI
* midlayer to retry such commands, which frequently will
* succeed and fix the error. The worst this can lead to
* is an occasional series of retries that will all fail. */
sdev->retry_hwerror = 1;
} else {
/* Non-disk-type devices don't need to blacklist any pages
* or to force 192-byte transfer lengths for MODE SENSE.
* But they do need to use MODE SENSE(10). */
sdev->use_10_for_ms = 1;
}
/* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
* REMOVAL command, so suppress those commands. */
if (us->flags & US_FL_NOT_LOCKABLE)
sdev->lockable = 0;
/* this is to satisfy the compiler, tho I don't think the
* return code is ever checked anywhere. */
return 0;
}
/* queue a command */
/* This is always called with scsi_lock(host) held */
static int queuecommand(struct scsi_cmnd *srb,
void (*done)(struct scsi_cmnd *))
{
struct us_data *us = host_to_us(srb->device->host);
US_DEBUGP("%s called\n", __FUNCTION__);
/* check for state-transition errors */
if (us->srb != NULL) {
printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
__FUNCTION__, us->srb);
return SCSI_MLQUEUE_HOST_BUSY;
}
/* fail the command if we are disconnecting */
if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
US_DEBUGP("Fail command during disconnect\n");
srb->result = DID_NO_CONNECT << 16;
done(srb);
return 0;
}
/* enqueue the command and wake up the control thread */
srb->scsi_done = done;
us->srb = srb;
up(&(us->sema));
return 0;
}
/***********************************************************************
* Error handling functions
***********************************************************************/
/* Command timeout and abort */
static int command_abort(struct scsi_cmnd *srb)
{
struct us_data *us = host_to_us(srb->device->host);
US_DEBUGP("%s called\n", __FUNCTION__);
/* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
* bits are protected by the host lock. */
scsi_lock(us_to_host(us));
/* Is this command still active? */
if (us->srb != srb) {
scsi_unlock(us_to_host(us));
US_DEBUGP ("-- nothing to abort\n");
return FAILED;
}
/* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
* a device reset isn't already in progress (to avoid interfering
* with the reset). Note that we must retain the host lock while
* calling usb_stor_stop_transport(); otherwise it might interfere
* with an auto-reset that begins as soon as we release the lock. */
set_bit(US_FLIDX_TIMED_OUT, &us->flags);
if (!test_bit(US_FLIDX_RESETTING, &us->flags)) {
set_bit(US_FLIDX_ABORTING, &us->flags);
usb_stor_stop_transport(us);
}
scsi_unlock(us_to_host(us));
/* Wait for the aborted command to finish */
wait_for_completion(&us->notify);
return SUCCESS;
}
/* This invokes the transport reset mechanism to reset the state of the
* device */
static int device_reset(struct scsi_cmnd *srb)
{
struct us_data *us = host_to_us(srb->device->host);
int result;
US_DEBUGP("%s called\n", __FUNCTION__);
/* lock the device pointers and do the reset */
mutex_lock(&(us->dev_mutex));
result = us->transport_reset(us);
mutex_unlock(&us->dev_mutex);
return result < 0 ? FAILED : SUCCESS;
}
/* Simulate a SCSI bus reset by resetting the device's USB port. */
static int bus_reset(struct scsi_cmnd *srb)
{
struct us_data *us = host_to_us(srb->device->host);
int result;
US_DEBUGP("%s called\n", __FUNCTION__);
result = usb_stor_port_reset(us);
return result < 0 ? FAILED : SUCCESS;
}
/* Report a driver-initiated device reset to the SCSI layer.
* Calling this for a SCSI-initiated reset is unnecessary but harmless.
* The caller must own the SCSI host lock. */
void usb_stor_report_device_reset(struct us_data *us)
{
int i;
struct Scsi_Host *host = us_to_host(us);
scsi_report_device_reset(host, 0, 0);
if (us->flags & US_FL_SCM_MULT_TARG) {
for (i = 1; i < host->max_id; ++i)
scsi_report_device_reset(host, 0, i);
}
}
/* Report a driver-initiated bus reset to the SCSI layer.
* Calling this for a SCSI-initiated reset is unnecessary but harmless.
* The caller must own the SCSI host lock. */
void usb_stor_report_bus_reset(struct us_data *us)
{
scsi_report_bus_reset(us_to_host(us), 0);
}
/***********************************************************************
* /proc/scsi/ functions
***********************************************************************/
/* we use this macro to help us write into the buffer */
#undef SPRINTF
#define SPRINTF(args...) \
do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
static int proc_info (struct Scsi_Host *host, char *buffer,
char **start, off_t offset, int length, int inout)
{
struct us_data *us = host_to_us(host);
char *pos = buffer;
const char *string;
/* if someone is sending us data, just throw it away */
if (inout)
return length;
/* print the controller name */
SPRINTF(" Host scsi%d: usb-storage\n", host->host_no);
/* print product, vendor, and serial number strings */
if (us->pusb_dev->manufacturer)
string = us->pusb_dev->manufacturer;
else if (us->unusual_dev->vendorName)
string = us->unusual_dev->vendorName;
else
string = "Unknown";
SPRINTF(" Vendor: %s\n", string);
if (us->pusb_dev->product)
string = us->pusb_dev->product;
else if (us->unusual_dev->productName)
string = us->unusual_dev->productName;
else
string = "Unknown";
SPRINTF(" Product: %s\n", string);
if (us->pusb_dev->serial)
string = us->pusb_dev->serial;
else
string = "None";
SPRINTF("Serial Number: %s\n", string);
/* show the protocol and transport */
SPRINTF(" Protocol: %s\n", us->protocol_name);
SPRINTF(" Transport: %s\n", us->transport_name);
/* show the device flags */
if (pos < buffer + length) {
pos += sprintf(pos, " Quirks:");
#define US_FLAG(name, value) \
if (us->flags & value) pos += sprintf(pos, " " #name);
US_DO_ALL_FLAGS
#undef US_FLAG
*(pos++) = '\n';
}
/*
* Calculate start of next buffer, and return value.
*/
*start = buffer + offset;
if ((pos - buffer) < offset)
return (0);
else if ((pos - buffer - offset) < length)
return (pos - buffer - offset);
else
return (length);
}
/***********************************************************************
* Sysfs interface
***********************************************************************/
/* Output routine for the sysfs max_sectors file */
static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
{
struct scsi_device *sdev = to_scsi_device(dev);
return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
}
/* Input routine for the sysfs max_sectors file */
static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
size_t count)
{
struct scsi_device *sdev = to_scsi_device(dev);
unsigned short ms;
if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
blk_queue_max_sectors(sdev->request_queue, ms);
return strlen(buf);
}
return -EINVAL;
}
static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
store_max_sectors);
static struct device_attribute *sysfs_device_attr_list[] = {
&dev_attr_max_sectors,
NULL,
};
/*
* this defines our host template, with which we'll allocate hosts
*/
struct scsi_host_template usb_stor_host_template = {
/* basic userland interface stuff */
.name = "usb-storage",
.proc_name = "usb-storage",
.proc_info = proc_info,
.info = host_info,
/* command interface -- queued only */
.queuecommand = queuecommand,
/* error and abort handlers */
.eh_abort_handler = command_abort,
.eh_device_reset_handler = device_reset,
.eh_bus_reset_handler = bus_reset,
/* queue commands only, only one command per LUN */
.can_queue = 1,
.cmd_per_lun = 1,
/* unknown initiator id */
.this_id = -1,
.slave_alloc = slave_alloc,
.slave_configure = slave_configure,
/* lots of sg segments can be handled */
.sg_tablesize = SG_ALL,
/* limit the total size of a transfer to 120 KB */
.max_sectors = 240,
/* merge commands... this seems to help performance, but
* periodically someone should test to see which setting is more
* optimal.
*/
.use_clustering = 1,
/* emulated HBA */
.emulated = 1,
/* we do our own delay after a device or bus reset */
.skip_settle_delay = 1,
/* sysfs device attributes */
.sdev_attrs = sysfs_device_attr_list,
/* module management */
.module = THIS_MODULE
};
/* To Report "Illegal Request: Invalid Field in CDB */
unsigned char usb_stor_sense_invalidCDB[18] = {
[0] = 0x70, /* current error */
[2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */
[7] = 0x0a, /* additional length */
[12] = 0x24 /* Invalid Field in CDB */
};
