1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SCSI functions used by both the initiator and the target code.
4 */
5
6#include <linux/bug.h>
7#include <linux/kernel.h>
8#include <linux/string.h>
9#include <linux/errno.h>
10#include <asm/unaligned.h>
11#include <scsi/scsi_common.h>
12
13/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
14 * You may not alter any existing entry (although adding new ones is
15 * encouraged once assigned by ANSI/INCITS T10).
16 */
17static const char *const scsi_device_types[] = {
18 "Direct-Access ",
19 "Sequential-Access",
20 "Printer ",
21 "Processor ",
22 "WORM ",
23 "CD-ROM ",
24 "Scanner ",
25 "Optical Device ",
26 "Medium Changer ",
27 "Communications ",
28 "ASC IT8 ",
29 "ASC IT8 ",
30 "RAID ",
31 "Enclosure ",
32 "Direct-Access-RBC",
33 "Optical card ",
34 "Bridge controller",
35 "Object storage ",
36 "Automation/Drive ",
37 "Security Manager ",
38 "Direct-Access-ZBC",
39};
40
41/**
42 * scsi_device_type - Return 17-char string indicating device type.
43 * @type: type number to look up
44 */
45const char *scsi_device_type(unsigned type)
46{
47 if (type == 0x1e)
48 return "Well-known LUN ";
49 if (type == 0x1f)
50 return "No Device ";
51 if (type >= ARRAY_SIZE(scsi_device_types))
52 return "Unknown ";
53 return scsi_device_types[type];
54}
55EXPORT_SYMBOL(scsi_device_type);
56
57/**
58 * scsilun_to_int - convert a scsi_lun to an int
59 * @scsilun: struct scsi_lun to be converted.
60 *
61 * Description:
62 * Convert @scsilun from a struct scsi_lun to a four-byte host byte-ordered
63 * integer, and return the result. The caller must check for
64 * truncation before using this function.
65 *
66 * Notes:
67 * For a description of the LUN format, post SCSI-3 see the SCSI
68 * Architecture Model, for SCSI-3 see the SCSI Controller Commands.
69 *
70 * Given a struct scsi_lun of: d2 04 0b 03 00 00 00 00, this function
71 * returns the integer: 0x0b03d204
72 *
73 * This encoding will return a standard integer LUN for LUNs smaller
74 * than 256, which typically use a single level LUN structure with
75 * addressing method 0.
76 */
77u64 scsilun_to_int(struct scsi_lun *scsilun)
78{
79 int i;
80 u64 lun;
81
82 lun = 0;
83 for (i = 0; i < sizeof(lun); i += 2)
84 lun = lun | (((u64)scsilun->scsi_lun[i] << ((i + 1) * 8)) |
85 ((u64)scsilun->scsi_lun[i + 1] << (i * 8)));
86 return lun;
87}
88EXPORT_SYMBOL(scsilun_to_int);
89
90/**
91 * int_to_scsilun - reverts an int into a scsi_lun
92 * @lun: integer to be reverted
93 * @scsilun: struct scsi_lun to be set.
94 *
95 * Description:
96 * Reverts the functionality of the scsilun_to_int, which packed
97 * an 8-byte lun value into an int. This routine unpacks the int
98 * back into the lun value.
99 *
100 * Notes:
101 * Given an integer : 0x0b03d204, this function returns a
102 * struct scsi_lun of: d2 04 0b 03 00 00 00 00
103 *
104 */
105void int_to_scsilun(u64 lun, struct scsi_lun *scsilun)
106{
107 int i;
108
109 memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
110
111 for (i = 0; i < sizeof(lun); i += 2) {
112 scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
113 scsilun->scsi_lun[i+1] = lun & 0xFF;
114 lun = lun >> 16;
115 }
116}
117EXPORT_SYMBOL(int_to_scsilun);
118
119/**
120 * scsi_normalize_sense - normalize main elements from either fixed or
121 * descriptor sense data format into a common format.
122 *
123 * @sense_buffer: byte array containing sense data returned by device
124 * @sb_len: number of valid bytes in sense_buffer
125 * @sshdr: pointer to instance of structure that common
126 * elements are written to.
127 *
128 * Notes:
129 * The "main elements" from sense data are: response_code, sense_key,
130 * asc, ascq and additional_length (only for descriptor format).
131 *
132 * Typically this function can be called after a device has
133 * responded to a SCSI command with the CHECK_CONDITION status.
134 *
135 * Return value:
136 * true if valid sense data information found, else false;
137 */
138bool scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
139 struct scsi_sense_hdr *sshdr)
140{
141 memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
142
143 if (!sense_buffer || !sb_len)
144 return false;
145
146 sshdr->response_code = (sense_buffer[0] & 0x7f);
147
148 if (!scsi_sense_valid(sshdr))
149 return false;
150
151 if (sshdr->response_code >= 0x72) {
152 /*
153 * descriptor format
154 */
155 if (sb_len > 1)
156 sshdr->sense_key = (sense_buffer[1] & 0xf);
157 if (sb_len > 2)
158 sshdr->asc = sense_buffer[2];
159 if (sb_len > 3)
160 sshdr->ascq = sense_buffer[3];
161 if (sb_len > 7)
162 sshdr->additional_length = sense_buffer[7];
163 } else {
164 /*
165 * fixed format
166 */
167 if (sb_len > 2)
168 sshdr->sense_key = (sense_buffer[2] & 0xf);
169 if (sb_len > 7) {
170 sb_len = (sb_len < (sense_buffer[7] + 8)) ?
171 sb_len : (sense_buffer[7] + 8);
172 if (sb_len > 12)
173 sshdr->asc = sense_buffer[12];
174 if (sb_len > 13)
175 sshdr->ascq = sense_buffer[13];
176 }
177 }
178
179 return true;
180}
181EXPORT_SYMBOL(scsi_normalize_sense);
182
183/**
184 * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
185 * @sense_buffer: byte array of descriptor format sense data
186 * @sb_len: number of valid bytes in sense_buffer
187 * @desc_type: value of descriptor type to find
188 * (e.g. 0 -> information)
189 *
190 * Notes:
191 * only valid when sense data is in descriptor format
192 *
193 * Return value:
194 * pointer to start of (first) descriptor if found else NULL
195 */
196const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
197 int desc_type)
198{
199 int add_sen_len, add_len, desc_len, k;
200 const u8 * descp;
201
202 if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
203 return NULL;
204 if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
205 return NULL;
206 add_sen_len = (add_sen_len < (sb_len - 8)) ?
207 add_sen_len : (sb_len - 8);
208 descp = &sense_buffer[8];
209 for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
210 descp += desc_len;
211 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
212 desc_len = add_len + 2;
213 if (descp[0] == desc_type)
214 return descp;
215 if (add_len < 0) // short descriptor ??
216 break;
217 }
218 return NULL;
219}
220EXPORT_SYMBOL(scsi_sense_desc_find);
221
222/**
223 * scsi_build_sense_buffer - build sense data in a buffer
224 * @desc: Sense format (non-zero == descriptor format,
225 * 0 == fixed format)
226 * @buf: Where to build sense data
227 * @key: Sense key
228 * @asc: Additional sense code
229 * @ascq: Additional sense code qualifier
230 *
231 **/
232void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
233{
234 if (desc) {
235 buf[0] = 0x72; /* descriptor, current */
236 buf[1] = key;
237 buf[2] = asc;
238 buf[3] = ascq;
239 buf[7] = 0;
240 } else {
241 buf[0] = 0x70; /* fixed, current */
242 buf[2] = key;
243 buf[7] = 0xa;
244 buf[12] = asc;
245 buf[13] = ascq;
246 }
247}
248EXPORT_SYMBOL(scsi_build_sense_buffer);
249
250/**
251 * scsi_set_sense_information - set the information field in a
252 * formatted sense data buffer
253 * @buf: Where to build sense data
254 * @buf_len: buffer length
255 * @info: 64-bit information value to be set
256 *
257 * Return value:
258 * 0 on success or -EINVAL for invalid sense buffer length
259 **/
260int scsi_set_sense_information(u8 *buf, int buf_len, u64 info)
261{
262 if ((buf[0] & 0x7f) == 0x72) {
263 u8 *ucp, len;
264
265 len = buf[7];
266 ucp = (char *)scsi_sense_desc_find(buf, len + 8, 0);
267 if (!ucp) {
268 buf[7] = len + 0xc;
269 ucp = buf + 8 + len;
270 }
271
272 if (buf_len < len + 0xc)
273 /* Not enough room for info */
274 return -EINVAL;
275
276 ucp[0] = 0;
277 ucp[1] = 0xa;
278 ucp[2] = 0x80; /* Valid bit */
279 ucp[3] = 0;
280 put_unaligned_be64(info, &ucp[4]);
281 } else if ((buf[0] & 0x7f) == 0x70) {
282 /*
283 * Only set the 'VALID' bit if we can represent the value
284 * correctly; otherwise just fill out the lower bytes and
285 * clear the 'VALID' flag.
286 */
287 if (info <= 0xffffffffUL)
288 buf[0] |= 0x80;
289 else
290 buf[0] &= 0x7f;
291 put_unaligned_be32((u32)info, &buf[3]);
292 }
293
294 return 0;
295}
296EXPORT_SYMBOL(scsi_set_sense_information);
297
298/**
299 * scsi_set_sense_field_pointer - set the field pointer sense key
300 * specific information in a formatted sense data buffer
301 * @buf: Where to build sense data
302 * @buf_len: buffer length
303 * @fp: field pointer to be set
304 * @bp: bit pointer to be set
305 * @cd: command/data bit
306 *
307 * Return value:
308 * 0 on success or -EINVAL for invalid sense buffer length
309 */
310int scsi_set_sense_field_pointer(u8 *buf, int buf_len, u16 fp, u8 bp, bool cd)
311{
312 u8 *ucp, len;
313
314 if ((buf[0] & 0x7f) == 0x72) {
315 len = buf[7];
316 ucp = (char *)scsi_sense_desc_find(buf, len + 8, 2);
317 if (!ucp) {
318 buf[7] = len + 8;
319 ucp = buf + 8 + len;
320 }
321
322 if (buf_len < len + 8)
323 /* Not enough room for info */
324 return -EINVAL;
325
326 ucp[0] = 2;
327 ucp[1] = 6;
328 ucp[4] = 0x80; /* Valid bit */
329 if (cd)
330 ucp[4] |= 0x40;
331 if (bp < 0x8)
332 ucp[4] |= 0x8 | bp;
333 put_unaligned_be16(fp, &ucp[5]);
334 } else if ((buf[0] & 0x7f) == 0x70) {
335 len = buf[7];
336 if (len < 18)
337 buf[7] = 18;
338
339 buf[15] = 0x80;
340 if (cd)
341 buf[15] |= 0x40;
342 if (bp < 0x8)
343 buf[15] |= 0x8 | bp;
344 put_unaligned_be16(fp, &buf[16]);
345 }
346
347 return 0;
348}
349EXPORT_SYMBOL(scsi_set_sense_field_pointer);
350