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1da177e4 | 1 | /* Driver for USB Mass Storage compliant devices |
1da177e4 LT |
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> | |
f940fcd8 | 46 | #include <linux/export.h> |
1da177e4 LT |
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 | ||
3dae5345 | 60 | void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us) |
1da177e4 | 61 | { |
2f640bf4 AS |
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. | |
1da177e4 LT |
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 | */ | |
fc8ef481 | 69 | for (; srb->cmd_len < 12; srb->cmd_len++) |
1da177e4 LT |
70 | srb->cmnd[srb->cmd_len] = 0; |
71 | ||
1da177e4 LT |
72 | /* send the command to the transport layer */ |
73 | usb_stor_invoke_transport(srb, us); | |
74 | } | |
75 | ||
1da177e4 LT |
76 | 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 | |
fc8ef481 | 79 | * UFI devices only accept 12 byte long commands |
1da177e4 LT |
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 */ | |
fc8ef481 | 86 | for (; srb->cmd_len < 12; srb->cmd_len++) |
1da177e4 LT |
87 | srb->cmnd[srb->cmd_len] = 0; |
88 | ||
89 | /* set command length to 12 bytes (this affects the transport layer) */ | |
90 | 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 | switch (srb->cmnd[0]) { | |
96 | ||
97 | /* for INQUIRY, UFI devices only ever return 36 bytes */ | |
98 | case INQUIRY: | |
99 | srb->cmnd[4] = 36; | |
100 | break; | |
101 | ||
102 | /* again, for MODE_SENSE_10, we get the minimum (8) */ | |
103 | case MODE_SENSE_10: | |
104 | srb->cmnd[7] = 0; | |
105 | srb->cmnd[8] = 8; | |
106 | break; | |
107 | ||
108 | /* for REQUEST_SENSE, UFI devices only ever return 18 bytes */ | |
109 | case REQUEST_SENSE: | |
110 | srb->cmnd[4] = 18; | |
111 | break; | |
112 | } /* end switch on cmnd[0] */ | |
113 | ||
114 | /* send the command to the transport layer */ | |
115 | usb_stor_invoke_transport(srb, us); | |
116 | } | |
117 | ||
118 | 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 | usb_stor_invoke_transport(srb, us); | |
123 | } | |
e6e244b6 | 124 | EXPORT_SYMBOL_GPL(usb_stor_transparent_scsi_command); |
1da177e4 LT |
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. | |
dd829d23 | 131 | * Update the **sgptr and *offset variables so that the next copy will |
7084191d AS |
132 | * pick up from where this one left off. |
133 | */ | |
1da177e4 | 134 | unsigned int usb_stor_access_xfer_buf(unsigned char *buffer, |
1f6f31a0 | 135 | unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr, |
1da177e4 LT |
136 | unsigned int *offset, enum xfer_buf_dir dir) |
137 | { | |
138 | unsigned int cnt; | |
7084191d | 139 | struct scatterlist *sg = *sgptr; |
1da177e4 | 140 | |
dd829d23 | 141 | /* We have to go through the list one entry |
1da177e4 LT |
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 | |
7084191d AS |
147 | * position in the kernel's virtual address space. |
148 | */ | |
dd829d23 BH |
149 | |
150 | if (!sg) | |
151 | sg = scsi_sglist(srb); | |
152 | ||
153 | /* This loop handles a single s-g list entry, which may | |
7084191d AS |
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 | */ | |
dd829d23 | 158 | cnt = 0; |
7084191d | 159 | while (cnt < buflen && sg) { |
dd829d23 BH |
160 | struct page *page = sg_page(sg) + |
161 | ((sg->offset + *offset) >> PAGE_SHIFT); | |
7084191d | 162 | unsigned int poff = (sg->offset + *offset) & (PAGE_SIZE-1); |
dd829d23 BH |
163 | unsigned int sglen = sg->length - *offset; |
164 | ||
165 | if (sglen > buflen - cnt) { | |
166 | ||
167 | /* Transfer ends within this s-g entry */ | |
168 | sglen = buflen - cnt; | |
169 | *offset += sglen; | |
170 | } else { | |
171 | ||
172 | /* Transfer continues to next s-g entry */ | |
173 | *offset = 0; | |
174 | 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 | while (sglen > 0) { | |
181 | unsigned int plen = min(sglen, (unsigned int) | |
182 | PAGE_SIZE - poff); | |
183 | unsigned char *ptr = kmap(page); | |
184 | ||
185 | if (dir == TO_XFER_BUF) | |
186 | memcpy(ptr + poff, buffer + cnt, plen); | |
187 | else | |
188 | memcpy(buffer + cnt, ptr + poff, plen); | |
189 | kunmap(page); | |
190 | ||
191 | /* Start at the beginning of the next page */ | |
192 | poff = 0; | |
193 | ++page; | |
194 | cnt += plen; | |
195 | sglen -= plen; | |
1da177e4 LT |
196 | } |
197 | } | |
dd829d23 | 198 | *sgptr = sg; |
1da177e4 LT |
199 | |
200 | /* Return the amount actually transferred */ | |
201 | return cnt; | |
202 | } | |
e6e244b6 | 203 | EXPORT_SYMBOL_GPL(usb_stor_access_xfer_buf); |
1da177e4 LT |
204 | |
205 | /* Store the contents of buffer into srb's transfer buffer and set the | |
7084191d AS |
206 | * SCSI residue. |
207 | */ | |
1da177e4 LT |
208 | void usb_stor_set_xfer_buf(unsigned char *buffer, |
209 | unsigned int buflen, struct scsi_cmnd *srb) | |
210 | { | |
1f6f31a0 JA |
211 | unsigned int offset = 0; |
212 | struct scatterlist *sg = NULL; | |
1da177e4 | 213 | |
6d512a80 | 214 | buflen = min(buflen, scsi_bufflen(srb)); |
7084191d | 215 | buflen = usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset, |
1da177e4 | 216 | TO_XFER_BUF); |
dd829d23 BH |
217 | if (buflen < scsi_bufflen(srb)) |
218 | scsi_set_resid(srb, scsi_bufflen(srb) - buflen); | |
1da177e4 | 219 | } |
e6e244b6 | 220 | EXPORT_SYMBOL_GPL(usb_stor_set_xfer_buf); |