![Alan Stern](/assets/img/avatar_default.png)
This patch (as1174) merges usb-storage's QIC-157 and ATAPI protocol routines. Since the two functions are identical, there's no reason to keep them separate. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
218 lines
6.8 KiB
C
218 lines
6.8 KiB
C
/* Driver for USB Mass Storage compliant devices
|
|
*
|
|
* 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) 2002 Alan Stern (stern@rowland.org)
|
|
*
|
|
* 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/highmem.h>
|
|
#include <scsi/scsi.h>
|
|
#include <scsi/scsi_cmnd.h>
|
|
|
|
#include "usb.h"
|
|
#include "protocol.h"
|
|
#include "debug.h"
|
|
#include "scsiglue.h"
|
|
#include "transport.h"
|
|
|
|
/***********************************************************************
|
|
* Protocol routines
|
|
***********************************************************************/
|
|
|
|
void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us)
|
|
{
|
|
/* Pad the SCSI command with zeros out to 12 bytes
|
|
*
|
|
* NOTE: This only works because a scsi_cmnd struct field contains
|
|
* a unsigned char cmnd[16], so we know we have storage available
|
|
*/
|
|
for (; srb->cmd_len<12; srb->cmd_len++)
|
|
srb->cmnd[srb->cmd_len] = 0;
|
|
|
|
/* set command length to 12 bytes */
|
|
srb->cmd_len = 12;
|
|
|
|
/* send the command to the transport layer */
|
|
usb_stor_invoke_transport(srb, us);
|
|
}
|
|
|
|
void usb_stor_ufi_command(struct scsi_cmnd *srb, struct us_data *us)
|
|
{
|
|
/* fix some commands -- this is a form of mode translation
|
|
* UFI devices only accept 12 byte long commands
|
|
*
|
|
* NOTE: This only works because a scsi_cmnd struct field contains
|
|
* a unsigned char cmnd[16], so we know we have storage available
|
|
*/
|
|
|
|
/* Pad the ATAPI command with zeros */
|
|
for (; srb->cmd_len<12; srb->cmd_len++)
|
|
srb->cmnd[srb->cmd_len] = 0;
|
|
|
|
/* set command length to 12 bytes (this affects the transport layer) */
|
|
srb->cmd_len = 12;
|
|
|
|
/* XXX We should be constantly re-evaluating the need for these */
|
|
|
|
/* determine the correct data length for these commands */
|
|
switch (srb->cmnd[0]) {
|
|
|
|
/* for INQUIRY, UFI devices only ever return 36 bytes */
|
|
case INQUIRY:
|
|
srb->cmnd[4] = 36;
|
|
break;
|
|
|
|
/* again, for MODE_SENSE_10, we get the minimum (8) */
|
|
case MODE_SENSE_10:
|
|
srb->cmnd[7] = 0;
|
|
srb->cmnd[8] = 8;
|
|
break;
|
|
|
|
/* for REQUEST_SENSE, UFI devices only ever return 18 bytes */
|
|
case REQUEST_SENSE:
|
|
srb->cmnd[4] = 18;
|
|
break;
|
|
} /* end switch on cmnd[0] */
|
|
|
|
/* send the command to the transport layer */
|
|
usb_stor_invoke_transport(srb, us);
|
|
}
|
|
|
|
void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb,
|
|
struct us_data *us)
|
|
{
|
|
/* send the command to the transport layer */
|
|
usb_stor_invoke_transport(srb, us);
|
|
}
|
|
|
|
/***********************************************************************
|
|
* Scatter-gather transfer buffer access routines
|
|
***********************************************************************/
|
|
|
|
/* Copy a buffer of length buflen to/from the srb's transfer buffer.
|
|
* Update the **sgptr and *offset variables so that the next copy will
|
|
* pick up from where this one left off.
|
|
*/
|
|
unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
|
|
unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr,
|
|
unsigned int *offset, enum xfer_buf_dir dir)
|
|
{
|
|
unsigned int cnt;
|
|
struct scatterlist *sg = *sgptr;
|
|
|
|
/* We have to go through the list one entry
|
|
* at a time. Each s-g entry contains some number of pages, and
|
|
* each page has to be kmap()'ed separately. If the page is already
|
|
* in kernel-addressable memory then kmap() will return its address.
|
|
* If the page is not directly accessible -- such as a user buffer
|
|
* located in high memory -- then kmap() will map it to a temporary
|
|
* position in the kernel's virtual address space.
|
|
*/
|
|
|
|
if (!sg)
|
|
sg = scsi_sglist(srb);
|
|
|
|
/* This loop handles a single s-g list entry, which may
|
|
* include multiple pages. Find the initial page structure
|
|
* and the starting offset within the page, and update
|
|
* the *offset and **sgptr values for the next loop.
|
|
*/
|
|
cnt = 0;
|
|
while (cnt < buflen && sg) {
|
|
struct page *page = sg_page(sg) +
|
|
((sg->offset + *offset) >> PAGE_SHIFT);
|
|
unsigned int poff = (sg->offset + *offset) & (PAGE_SIZE-1);
|
|
unsigned int sglen = sg->length - *offset;
|
|
|
|
if (sglen > buflen - cnt) {
|
|
|
|
/* Transfer ends within this s-g entry */
|
|
sglen = buflen - cnt;
|
|
*offset += sglen;
|
|
} else {
|
|
|
|
/* Transfer continues to next s-g entry */
|
|
*offset = 0;
|
|
sg = sg_next(sg);
|
|
}
|
|
|
|
/* Transfer the data for all the pages in this
|
|
* s-g entry. For each page: call kmap(), do the
|
|
* transfer, and call kunmap() immediately after. */
|
|
while (sglen > 0) {
|
|
unsigned int plen = min(sglen, (unsigned int)
|
|
PAGE_SIZE - poff);
|
|
unsigned char *ptr = kmap(page);
|
|
|
|
if (dir == TO_XFER_BUF)
|
|
memcpy(ptr + poff, buffer + cnt, plen);
|
|
else
|
|
memcpy(buffer + cnt, ptr + poff, plen);
|
|
kunmap(page);
|
|
|
|
/* Start at the beginning of the next page */
|
|
poff = 0;
|
|
++page;
|
|
cnt += plen;
|
|
sglen -= plen;
|
|
}
|
|
}
|
|
*sgptr = sg;
|
|
|
|
/* Return the amount actually transferred */
|
|
return cnt;
|
|
}
|
|
|
|
/* Store the contents of buffer into srb's transfer buffer and set the
|
|
* SCSI residue.
|
|
*/
|
|
void usb_stor_set_xfer_buf(unsigned char *buffer,
|
|
unsigned int buflen, struct scsi_cmnd *srb)
|
|
{
|
|
unsigned int offset = 0;
|
|
struct scatterlist *sg = NULL;
|
|
|
|
buflen = min(buflen, scsi_bufflen(srb));
|
|
buflen = usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset,
|
|
TO_XFER_BUF);
|
|
if (buflen < scsi_bufflen(srb))
|
|
scsi_set_resid(srb, scsi_bufflen(srb) - buflen);
|
|
}
|