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5fd54ace | 1 | // SPDX-License-Identifier: GPL-2.0+ |
f0183a33 FB |
2 | /* |
3 | * Driver for USB Mass Storage compliant devices | |
1da177e4 LT |
4 | * |
5 | * Current development and maintenance by: | |
6 | * (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net) | |
7 | * | |
8 | * Developed with the assistance of: | |
9 | * (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org) | |
10 | * (c) 2002 Alan Stern (stern@rowland.org) | |
11 | * | |
12 | * Initial work by: | |
13 | * (c) 1999 Michael Gee (michael@linuxspecific.com) | |
14 | * | |
15 | * This driver is based on the 'USB Mass Storage Class' document. This | |
16 | * describes in detail the protocol used to communicate with such | |
17 | * devices. Clearly, the designers had SCSI and ATAPI commands in | |
18 | * mind when they created this document. The commands are all very | |
19 | * similar to commands in the SCSI-II and ATAPI specifications. | |
20 | * | |
21 | * It is important to note that in a number of cases this class | |
22 | * exhibits class-specific exemptions from the USB specification. | |
23 | * Notably the usage of NAK, STALL and ACK differs from the norm, in | |
24 | * that they are used to communicate wait, failed and OK on commands. | |
25 | * | |
26 | * Also, for certain devices, the interrupt endpoint is used to convey | |
27 | * status of a command. | |
1da177e4 LT |
28 | */ |
29 | ||
30 | #include <linux/highmem.h> | |
f940fcd8 | 31 | #include <linux/export.h> |
1da177e4 LT |
32 | #include <scsi/scsi.h> |
33 | #include <scsi/scsi_cmnd.h> | |
34 | ||
35 | #include "usb.h" | |
36 | #include "protocol.h" | |
37 | #include "debug.h" | |
38 | #include "scsiglue.h" | |
39 | #include "transport.h" | |
40 | ||
41 | /*********************************************************************** | |
42 | * Protocol routines | |
43 | ***********************************************************************/ | |
44 | ||
3dae5345 | 45 | void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us) |
1da177e4 | 46 | { |
2f640bf4 AS |
47 | /* |
48 | * Pad the SCSI command with zeros out to 12 bytes. If the | |
49 | * command already is 12 bytes or longer, leave it alone. | |
1da177e4 LT |
50 | * |
51 | * NOTE: This only works because a scsi_cmnd struct field contains | |
52 | * a unsigned char cmnd[16], so we know we have storage available | |
53 | */ | |
fc8ef481 | 54 | for (; srb->cmd_len < 12; srb->cmd_len++) |
1da177e4 LT |
55 | srb->cmnd[srb->cmd_len] = 0; |
56 | ||
1da177e4 LT |
57 | /* send the command to the transport layer */ |
58 | usb_stor_invoke_transport(srb, us); | |
59 | } | |
60 | ||
1da177e4 LT |
61 | void usb_stor_ufi_command(struct scsi_cmnd *srb, struct us_data *us) |
62 | { | |
f0183a33 FB |
63 | /* |
64 | * fix some commands -- this is a form of mode translation | |
fc8ef481 | 65 | * UFI devices only accept 12 byte long commands |
1da177e4 LT |
66 | * |
67 | * NOTE: This only works because a scsi_cmnd struct field contains | |
68 | * a unsigned char cmnd[16], so we know we have storage available | |
69 | */ | |
70 | ||
71 | /* Pad the ATAPI command with zeros */ | |
fc8ef481 | 72 | for (; srb->cmd_len < 12; srb->cmd_len++) |
1da177e4 LT |
73 | srb->cmnd[srb->cmd_len] = 0; |
74 | ||
75 | /* set command length to 12 bytes (this affects the transport layer) */ | |
76 | srb->cmd_len = 12; | |
77 | ||
78 | /* XXX We should be constantly re-evaluating the need for these */ | |
79 | ||
80 | /* determine the correct data length for these commands */ | |
81 | switch (srb->cmnd[0]) { | |
82 | ||
83 | /* for INQUIRY, UFI devices only ever return 36 bytes */ | |
84 | case INQUIRY: | |
85 | srb->cmnd[4] = 36; | |
86 | break; | |
87 | ||
88 | /* again, for MODE_SENSE_10, we get the minimum (8) */ | |
89 | case MODE_SENSE_10: | |
90 | srb->cmnd[7] = 0; | |
91 | srb->cmnd[8] = 8; | |
92 | break; | |
93 | ||
94 | /* for REQUEST_SENSE, UFI devices only ever return 18 bytes */ | |
95 | case REQUEST_SENSE: | |
96 | srb->cmnd[4] = 18; | |
97 | break; | |
98 | } /* end switch on cmnd[0] */ | |
99 | ||
100 | /* send the command to the transport layer */ | |
101 | usb_stor_invoke_transport(srb, us); | |
102 | } | |
103 | ||
104 | void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb, | |
105 | struct us_data *us) | |
106 | { | |
107 | /* send the command to the transport layer */ | |
108 | usb_stor_invoke_transport(srb, us); | |
109 | } | |
e6e244b6 | 110 | EXPORT_SYMBOL_GPL(usb_stor_transparent_scsi_command); |
1da177e4 LT |
111 | |
112 | /*********************************************************************** | |
113 | * Scatter-gather transfer buffer access routines | |
114 | ***********************************************************************/ | |
115 | ||
f0183a33 FB |
116 | /* |
117 | * Copy a buffer of length buflen to/from the srb's transfer buffer. | |
dd829d23 | 118 | * Update the **sgptr and *offset variables so that the next copy will |
7084191d AS |
119 | * pick up from where this one left off. |
120 | */ | |
1da177e4 | 121 | unsigned int usb_stor_access_xfer_buf(unsigned char *buffer, |
1f6f31a0 | 122 | unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr, |
1da177e4 LT |
123 | unsigned int *offset, enum xfer_buf_dir dir) |
124 | { | |
e5fc70d5 | 125 | unsigned int cnt = 0; |
7084191d | 126 | struct scatterlist *sg = *sgptr; |
e5fc70d5 ML |
127 | struct sg_mapping_iter miter; |
128 | unsigned int nents = scsi_sg_count(srb); | |
1da177e4 | 129 | |
e5fc70d5 ML |
130 | if (sg) |
131 | nents = sg_nents(sg); | |
132 | else | |
dd829d23 BH |
133 | sg = scsi_sglist(srb); |
134 | ||
e5fc70d5 ML |
135 | sg_miter_start(&miter, sg, nents, dir == FROM_XFER_BUF ? |
136 | SG_MITER_FROM_SG: SG_MITER_TO_SG); | |
dd829d23 | 137 | |
e5fc70d5 ML |
138 | if (!sg_miter_skip(&miter, *offset)) |
139 | return cnt; | |
140 | ||
141 | while (sg_miter_next(&miter) && cnt < buflen) { | |
40fcd88b ML |
142 | unsigned int len = min_t(unsigned int, miter.length, |
143 | buflen - cnt); | |
e5fc70d5 ML |
144 | |
145 | if (dir == FROM_XFER_BUF) | |
146 | memcpy(buffer + cnt, miter.addr, len); | |
147 | else | |
148 | memcpy(miter.addr, buffer + cnt, len); | |
dd829d23 | 149 | |
e5fc70d5 ML |
150 | if (*offset + len < miter.piter.sg->length) { |
151 | *offset += len; | |
152 | *sgptr = miter.piter.sg; | |
153 | } else { | |
154 | *offset = 0; | |
155 | *sgptr = sg_next(miter.piter.sg); | |
1da177e4 | 156 | } |
e5fc70d5 | 157 | cnt += len; |
1da177e4 | 158 | } |
e5fc70d5 | 159 | sg_miter_stop(&miter); |
1da177e4 | 160 | |
1da177e4 LT |
161 | return cnt; |
162 | } | |
e6e244b6 | 163 | EXPORT_SYMBOL_GPL(usb_stor_access_xfer_buf); |
1da177e4 | 164 | |
f0183a33 FB |
165 | /* |
166 | * Store the contents of buffer into srb's transfer buffer and set the | |
7084191d AS |
167 | * SCSI residue. |
168 | */ | |
1da177e4 LT |
169 | void usb_stor_set_xfer_buf(unsigned char *buffer, |
170 | unsigned int buflen, struct scsi_cmnd *srb) | |
171 | { | |
1f6f31a0 JA |
172 | unsigned int offset = 0; |
173 | struct scatterlist *sg = NULL; | |
1da177e4 | 174 | |
6d512a80 | 175 | buflen = min(buflen, scsi_bufflen(srb)); |
7084191d | 176 | buflen = usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset, |
1da177e4 | 177 | TO_XFER_BUF); |
dd829d23 BH |
178 | if (buflen < scsi_bufflen(srb)) |
179 | scsi_set_resid(srb, scsi_bufflen(srb) - buflen); | |
1da177e4 | 180 | } |
e6e244b6 | 181 | EXPORT_SYMBOL_GPL(usb_stor_set_xfer_buf); |