Branch data Line data Source code
1 : : /* Driver for USB Mass Storage compliant devices
2 : : *
3 : : * Current development and maintenance by:
4 : : * (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
5 : : *
6 : : * Developed with the assistance of:
7 : : * (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
8 : : * (c) 2002 Alan Stern (stern@rowland.org)
9 : : *
10 : : * Initial work by:
11 : : * (c) 1999 Michael Gee (michael@linuxspecific.com)
12 : : *
13 : : * This driver is based on the 'USB Mass Storage Class' document. This
14 : : * describes in detail the protocol used to communicate with such
15 : : * devices. Clearly, the designers had SCSI and ATAPI commands in
16 : : * mind when they created this document. The commands are all very
17 : : * similar to commands in the SCSI-II and ATAPI specifications.
18 : : *
19 : : * It is important to note that in a number of cases this class
20 : : * exhibits class-specific exemptions from the USB specification.
21 : : * Notably the usage of NAK, STALL and ACK differs from the norm, in
22 : : * that they are used to communicate wait, failed and OK on commands.
23 : : *
24 : : * Also, for certain devices, the interrupt endpoint is used to convey
25 : : * status of a command.
26 : : *
27 : : * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
28 : : * information about this driver.
29 : : *
30 : : * This program is free software; you can redistribute it and/or modify it
31 : : * under the terms of the GNU General Public License as published by the
32 : : * Free Software Foundation; either version 2, or (at your option) any
33 : : * later version.
34 : : *
35 : : * This program is distributed in the hope that it will be useful, but
36 : : * WITHOUT ANY WARRANTY; without even the implied warranty of
37 : : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
38 : : * General Public License for more details.
39 : : *
40 : : * You should have received a copy of the GNU General Public License along
41 : : * with this program; if not, write to the Free Software Foundation, Inc.,
42 : : * 675 Mass Ave, Cambridge, MA 02139, USA.
43 : : */
44 : :
45 : : #include <linux/highmem.h>
46 : : #include <linux/export.h>
47 : : #include <scsi/scsi.h>
48 : : #include <scsi/scsi_cmnd.h>
49 : :
50 : : #include "usb.h"
51 : : #include "protocol.h"
52 : : #include "debug.h"
53 : : #include "scsiglue.h"
54 : : #include "transport.h"
55 : :
56 : : /***********************************************************************
57 : : * Protocol routines
58 : : ***********************************************************************/
59 : :
60 : 0 : void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us)
61 : : {
62 : : /*
63 : : * Pad the SCSI command with zeros out to 12 bytes. If the
64 : : * command already is 12 bytes or longer, leave it alone.
65 : : *
66 : : * NOTE: This only works because a scsi_cmnd struct field contains
67 : : * a unsigned char cmnd[16], so we know we have storage available
68 : : */
69 [ # # ]: 0 : for (; srb->cmd_len < 12; srb->cmd_len++)
70 : 0 : srb->cmnd[srb->cmd_len] = 0;
71 : :
72 : : /* send the command to the transport layer */
73 : 0 : usb_stor_invoke_transport(srb, us);
74 : 0 : }
75 : :
76 : 0 : void usb_stor_ufi_command(struct scsi_cmnd *srb, struct us_data *us)
77 : : {
78 : : /* fix some commands -- this is a form of mode translation
79 : : * UFI devices only accept 12 byte long commands
80 : : *
81 : : * NOTE: This only works because a scsi_cmnd struct field contains
82 : : * a unsigned char cmnd[16], so we know we have storage available
83 : : */
84 : :
85 : : /* Pad the ATAPI command with zeros */
86 [ # # ]: 0 : for (; srb->cmd_len < 12; srb->cmd_len++)
87 : 0 : srb->cmnd[srb->cmd_len] = 0;
88 : :
89 : : /* set command length to 12 bytes (this affects the transport layer) */
90 : 0 : srb->cmd_len = 12;
91 : :
92 : : /* XXX We should be constantly re-evaluating the need for these */
93 : :
94 : : /* determine the correct data length for these commands */
95 [ # # # # ]: 0 : switch (srb->cmnd[0]) {
96 : :
97 : : /* for INQUIRY, UFI devices only ever return 36 bytes */
98 : : case INQUIRY:
99 : 0 : srb->cmnd[4] = 36;
100 : 0 : break;
101 : :
102 : : /* again, for MODE_SENSE_10, we get the minimum (8) */
103 : : case MODE_SENSE_10:
104 : 0 : srb->cmnd[7] = 0;
105 : 0 : srb->cmnd[8] = 8;
106 : 0 : break;
107 : :
108 : : /* for REQUEST_SENSE, UFI devices only ever return 18 bytes */
109 : : case REQUEST_SENSE:
110 : 0 : srb->cmnd[4] = 18;
111 : 0 : break;
112 : : } /* end switch on cmnd[0] */
113 : :
114 : : /* send the command to the transport layer */
115 : 0 : usb_stor_invoke_transport(srb, us);
116 : 0 : }
117 : :
118 : 0 : void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb,
119 : : struct us_data *us)
120 : : {
121 : : /* send the command to the transport layer */
122 : 433719 : usb_stor_invoke_transport(srb, us);
123 : 433719 : }
124 : : EXPORT_SYMBOL_GPL(usb_stor_transparent_scsi_command);
125 : :
126 : : /***********************************************************************
127 : : * Scatter-gather transfer buffer access routines
128 : : ***********************************************************************/
129 : :
130 : : /* Copy a buffer of length buflen to/from the srb's transfer buffer.
131 : : * Update the **sgptr and *offset variables so that the next copy will
132 : : * pick up from where this one left off.
133 : : */
134 : 0 : unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
135 : : unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr,
136 : : unsigned int *offset, enum xfer_buf_dir dir)
137 : : {
138 : : unsigned int cnt;
139 : 0 : struct scatterlist *sg = *sgptr;
140 : :
141 : : /* We have to go through the list one entry
142 : : * at a time. Each s-g entry contains some number of pages, and
143 : : * each page has to be kmap()'ed separately. If the page is already
144 : : * in kernel-addressable memory then kmap() will return its address.
145 : : * If the page is not directly accessible -- such as a user buffer
146 : : * located in high memory -- then kmap() will map it to a temporary
147 : : * position in the kernel's virtual address space.
148 : : */
149 : :
150 [ # # ]: 0 : if (!sg)
151 : : sg = scsi_sglist(srb);
152 : :
153 : : /* This loop handles a single s-g list entry, which may
154 : : * include multiple pages. Find the initial page structure
155 : : * and the starting offset within the page, and update
156 : : * the *offset and **sgptr values for the next loop.
157 : : */
158 : : cnt = 0;
159 [ # # ]: 0 : while (cnt < buflen && sg) {
160 : 0 : struct page *page = sg_page(sg) +
161 : 0 : ((sg->offset + *offset) >> PAGE_SHIFT);
162 : 0 : unsigned int poff = (sg->offset + *offset) & (PAGE_SIZE-1);
163 : 0 : unsigned int sglen = sg->length - *offset;
164 : :
165 [ # # ]: 0 : if (sglen > buflen - cnt) {
166 : :
167 : : /* Transfer ends within this s-g entry */
168 : : sglen = buflen - cnt;
169 : 0 : *offset += sglen;
170 : : } else {
171 : :
172 : : /* Transfer continues to next s-g entry */
173 : 0 : *offset = 0;
174 : 0 : sg = sg_next(sg);
175 : : }
176 : :
177 : : /* Transfer the data for all the pages in this
178 : : * s-g entry. For each page: call kmap(), do the
179 : : * transfer, and call kunmap() immediately after. */
180 [ # # ]: 0 : while (sglen > 0) {
181 : 0 : unsigned int plen = min(sglen, (unsigned int)
182 : : PAGE_SIZE - poff);
183 : 0 : unsigned char *ptr = kmap(page);
184 : :
185 [ # # ]: 0 : if (dir == TO_XFER_BUF)
186 : 0 : memcpy(ptr + poff, buffer + cnt, plen);
187 : : else
188 : 0 : memcpy(buffer + cnt, ptr + poff, plen);
189 : 0 : kunmap(page);
190 : :
191 : : /* Start at the beginning of the next page */
192 : : poff = 0;
193 : 0 : ++page;
194 : 0 : cnt += plen;
195 : 0 : sglen -= plen;
196 : : }
197 : : }
198 : 0 : *sgptr = sg;
199 : :
200 : : /* Return the amount actually transferred */
201 : 0 : return cnt;
202 : : }
203 : : EXPORT_SYMBOL_GPL(usb_stor_access_xfer_buf);
204 : :
205 : : /* Store the contents of buffer into srb's transfer buffer and set the
206 : : * SCSI residue.
207 : : */
208 : 0 : void usb_stor_set_xfer_buf(unsigned char *buffer,
209 : : unsigned int buflen, struct scsi_cmnd *srb)
210 : : {
211 : 0 : unsigned int offset = 0;
212 : 0 : struct scatterlist *sg = NULL;
213 : :
214 : 0 : buflen = min(buflen, scsi_bufflen(srb));
215 : 0 : buflen = usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset,
216 : : TO_XFER_BUF);
217 [ # # ]: 0 : if (buflen < scsi_bufflen(srb))
218 : 0 : scsi_set_resid(srb, scsi_bufflen(srb) - buflen);
219 : 0 : }
220 : : EXPORT_SYMBOL_GPL(usb_stor_set_xfer_buf);
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