1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
|
/* 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 <linux/export.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. If the
* command already is 12 bytes or longer, leave it alone.
*
* 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;
/* 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);
}
EXPORT_SYMBOL_GPL(usb_stor_transparent_scsi_command);
/***********************************************************************
* 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 = 0;
struct scatterlist *sg = *sgptr;
struct sg_mapping_iter miter;
unsigned int nents = scsi_sg_count(srb);
if (sg)
nents = sg_nents(sg);
else
sg = scsi_sglist(srb);
sg_miter_start(&miter, sg, nents, dir == FROM_XFER_BUF ?
SG_MITER_FROM_SG: SG_MITER_TO_SG);
if (!sg_miter_skip(&miter, *offset))
return cnt;
while (sg_miter_next(&miter) && cnt < buflen) {
unsigned int len = min(miter.length, buflen - cnt);
if (dir == FROM_XFER_BUF)
memcpy(buffer + cnt, miter.addr, len);
else
memcpy(miter.addr, buffer + cnt, len);
if (*offset + len < miter.piter.sg->length) {
*offset += len;
*sgptr = miter.piter.sg;
} else {
*offset = 0;
*sgptr = sg_next(miter.piter.sg);
}
cnt += len;
}
sg_miter_stop(&miter);
return cnt;
}
EXPORT_SYMBOL_GPL(usb_stor_access_xfer_buf);
/* 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);
}
EXPORT_SYMBOL_GPL(usb_stor_set_xfer_buf);
|
