1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Simulated SCSI driver.
4 *
5 * Copyright (C) 1999, 2001-2003 Hewlett-Packard Co
6 * David Mosberger-Tang <davidm@hpl.hp.com>
7 * Stephane Eranian <eranian@hpl.hp.com>
8 *
9 * 02/01/15 David Mosberger Updated for v2.5.1
10 * 99/12/18 David Mosberger Added support for READ10/WRITE10 needed by linux v2.3.33
11 */
12 #include <linux/blkdev.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/kernel.h>
16 #include <linux/timer.h>
17 #include <asm/irq.h>
18 #include "hpsim_ssc.h"
19
20 #include <scsi/scsi.h>
21 #include <scsi/scsi_cmnd.h>
22 #include <scsi/scsi_device.h>
23 #include <scsi/scsi_host.h>
24
25 #define DEBUG_SIMSCSI 0
26
27 #define SIMSCSI_REQ_QUEUE_LEN 64
28 #define DEFAULT_SIMSCSI_ROOT "/var/ski-disks/sd"
29
30 /* Simulator system calls: */
31
32 #define SSC_OPEN 50
33 #define SSC_CLOSE 51
34 #define SSC_READ 52
35 #define SSC_WRITE 53
36 #define SSC_GET_COMPLETION 54
37 #define SSC_WAIT_COMPLETION 55
38
39 #define SSC_WRITE_ACCESS 2
40 #define SSC_READ_ACCESS 1
41
42 #if DEBUG_SIMSCSI
43 int simscsi_debug;
44 # define DBG simscsi_debug
45 #else
46 # define DBG 0
47 #endif
48
49 static struct Scsi_Host *host;
50
51 static void simscsi_interrupt (unsigned long val);
52 static DECLARE_TASKLET(simscsi_tasklet, simscsi_interrupt, 0);
53
54 struct disk_req {
55 unsigned long addr;
56 unsigned len;
57 };
58
59 struct disk_stat {
60 int fd;
61 unsigned count;
62 };
63
64 static int desc[16] = {
65 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
66 };
67
68 static struct queue_entry {
69 struct scsi_cmnd *sc;
70 } queue[SIMSCSI_REQ_QUEUE_LEN];
71
72 static int rd, wr;
73 static atomic_t num_reqs = ATOMIC_INIT(0);
74
75 /* base name for default disks */
76 static char *simscsi_root = DEFAULT_SIMSCSI_ROOT;
77
78 #define MAX_ROOT_LEN 128
79
80 /*
81 * used to setup a new base for disk images
82 * to use /foo/bar/disk[a-z] as disk images
83 * you have to specify simscsi=/foo/bar/disk on the command line
84 */
85 static int __init
simscsi_setup(char * s)86 simscsi_setup (char *s)
87 {
88 /* XXX Fix me we may need to strcpy() ? */
89 if (strlen(s) > MAX_ROOT_LEN) {
90 printk(KERN_ERR "simscsi_setup: prefix too long---using default %s\n",
91 simscsi_root);
92 } else
93 simscsi_root = s;
94 return 1;
95 }
96
97 __setup("simscsi=", simscsi_setup);
98
99 static void
simscsi_interrupt(unsigned long val)100 simscsi_interrupt (unsigned long val)
101 {
102 struct scsi_cmnd *sc;
103
104 while ((sc = queue[rd].sc) != NULL) {
105 atomic_dec(&num_reqs);
106 queue[rd].sc = NULL;
107 if (DBG)
108 printk("simscsi_interrupt: done with %ld\n", sc->serial_number);
109 (*sc->scsi_done)(sc);
110 rd = (rd + 1) % SIMSCSI_REQ_QUEUE_LEN;
111 }
112 }
113
114 static int
simscsi_biosparam(struct scsi_device * sdev,struct block_device * n,sector_t capacity,int ip[])115 simscsi_biosparam (struct scsi_device *sdev, struct block_device *n,
116 sector_t capacity, int ip[])
117 {
118 ip[0] = 64; /* heads */
119 ip[1] = 32; /* sectors */
120 ip[2] = capacity >> 11; /* cylinders */
121 return 0;
122 }
123
124 static void
simscsi_sg_readwrite(struct scsi_cmnd * sc,int mode,unsigned long offset)125 simscsi_sg_readwrite (struct scsi_cmnd *sc, int mode, unsigned long offset)
126 {
127 int i;
128 struct scatterlist *sl;
129 struct disk_stat stat;
130 struct disk_req req;
131
132 stat.fd = desc[sc->device->id];
133
134 scsi_for_each_sg(sc, sl, scsi_sg_count(sc), i) {
135 req.addr = __pa(sg_virt(sl));
136 req.len = sl->length;
137 if (DBG)
138 printk("simscsi_sg_%s @ %lx (off %lx) use_sg=%d len=%d\n",
139 mode == SSC_READ ? "read":"write", req.addr, offset,
140 scsi_sg_count(sc) - i, sl->length);
141 ia64_ssc(stat.fd, 1, __pa(&req), offset, mode);
142 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
143
144 /* should not happen in our case */
145 if (stat.count != req.len) {
146 sc->result = DID_ERROR << 16;
147 return;
148 }
149 offset += sl->length;
150 }
151 sc->result = GOOD;
152 }
153
154 /*
155 * function handling both READ_6/WRITE_6 (non-scatter/gather mode)
156 * commands.
157 * Added 02/26/99 S.Eranian
158 */
159 static void
simscsi_readwrite6(struct scsi_cmnd * sc,int mode)160 simscsi_readwrite6 (struct scsi_cmnd *sc, int mode)
161 {
162 unsigned long offset;
163
164 offset = (((sc->cmnd[1] & 0x1f) << 16) | (sc->cmnd[2] << 8) | sc->cmnd[3])*512;
165 simscsi_sg_readwrite(sc, mode, offset);
166 }
167
168 static size_t
simscsi_get_disk_size(int fd)169 simscsi_get_disk_size (int fd)
170 {
171 struct disk_stat stat;
172 size_t bit, sectors = 0;
173 struct disk_req req;
174 char buf[512];
175
176 /*
177 * This is a bit kludgey: the simulator doesn't provide a
178 * direct way of determining the disk size, so we do a binary
179 * search, assuming a maximum disk size of 128GB.
180 */
181 for (bit = (128UL << 30)/512; bit != 0; bit >>= 1) {
182 req.addr = __pa(&buf);
183 req.len = sizeof(buf);
184 ia64_ssc(fd, 1, __pa(&req), ((sectors | bit) - 1)*512, SSC_READ);
185 stat.fd = fd;
186 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
187 if (stat.count == sizeof(buf))
188 sectors |= bit;
189 }
190 return sectors - 1; /* return last valid sector number */
191 }
192
193 static void
simscsi_readwrite10(struct scsi_cmnd * sc,int mode)194 simscsi_readwrite10 (struct scsi_cmnd *sc, int mode)
195 {
196 unsigned long offset;
197
198 offset = (((unsigned long)sc->cmnd[2] << 24)
199 | ((unsigned long)sc->cmnd[3] << 16)
200 | ((unsigned long)sc->cmnd[4] << 8)
201 | ((unsigned long)sc->cmnd[5] << 0))*512UL;
202 simscsi_sg_readwrite(sc, mode, offset);
203 }
204
205 static int
simscsi_queuecommand_lck(struct scsi_cmnd * sc,void (* done)(struct scsi_cmnd *))206 simscsi_queuecommand_lck (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
207 {
208 unsigned int target_id = sc->device->id;
209 char fname[MAX_ROOT_LEN+16];
210 size_t disk_size;
211 char *buf;
212 char localbuf[36];
213 #if DEBUG_SIMSCSI
214 register long sp asm ("sp");
215
216 if (DBG)
217 printk("simscsi_queuecommand: target=%d,cmnd=%u,sc=%lu,sp=%lx,done=%p\n",
218 target_id, sc->cmnd[0], sc->serial_number, sp, done);
219 #endif
220
221 sc->result = DID_BAD_TARGET << 16;
222 sc->scsi_done = done;
223 if (target_id <= 15 && sc->device->lun == 0) {
224 switch (sc->cmnd[0]) {
225 case INQUIRY:
226 if (scsi_bufflen(sc) < 35) {
227 break;
228 }
229 sprintf (fname, "%s%c", simscsi_root, 'a' + target_id);
230 desc[target_id] = ia64_ssc(__pa(fname), SSC_READ_ACCESS|SSC_WRITE_ACCESS,
231 0, 0, SSC_OPEN);
232 if (desc[target_id] < 0) {
233 /* disk doesn't exist... */
234 break;
235 }
236 buf = localbuf;
237 buf[0] = 0; /* magnetic disk */
238 buf[1] = 0; /* not a removable medium */
239 buf[2] = 2; /* SCSI-2 compliant device */
240 buf[3] = 2; /* SCSI-2 response data format */
241 buf[4] = 31; /* additional length (bytes) */
242 buf[5] = 0; /* reserved */
243 buf[6] = 0; /* reserved */
244 buf[7] = 0; /* various flags */
245 memcpy(buf + 8, "HP SIMULATED DISK 0.00", 28);
246 scsi_sg_copy_from_buffer(sc, buf, 36);
247 sc->result = GOOD;
248 break;
249
250 case TEST_UNIT_READY:
251 sc->result = GOOD;
252 break;
253
254 case READ_6:
255 if (desc[target_id] < 0 )
256 break;
257 simscsi_readwrite6(sc, SSC_READ);
258 break;
259
260 case READ_10:
261 if (desc[target_id] < 0 )
262 break;
263 simscsi_readwrite10(sc, SSC_READ);
264 break;
265
266 case WRITE_6:
267 if (desc[target_id] < 0)
268 break;
269 simscsi_readwrite6(sc, SSC_WRITE);
270 break;
271
272 case WRITE_10:
273 if (desc[target_id] < 0)
274 break;
275 simscsi_readwrite10(sc, SSC_WRITE);
276 break;
277
278 case READ_CAPACITY:
279 if (desc[target_id] < 0 || scsi_bufflen(sc) < 8) {
280 break;
281 }
282 buf = localbuf;
283 disk_size = simscsi_get_disk_size(desc[target_id]);
284
285 buf[0] = (disk_size >> 24) & 0xff;
286 buf[1] = (disk_size >> 16) & 0xff;
287 buf[2] = (disk_size >> 8) & 0xff;
288 buf[3] = (disk_size >> 0) & 0xff;
289 /* set block size of 512 bytes: */
290 buf[4] = 0;
291 buf[5] = 0;
292 buf[6] = 2;
293 buf[7] = 0;
294 scsi_sg_copy_from_buffer(sc, buf, 8);
295 sc->result = GOOD;
296 break;
297
298 case MODE_SENSE:
299 case MODE_SENSE_10:
300 /* sd.c uses this to determine whether disk does write-caching. */
301 scsi_sg_copy_from_buffer(sc, (char *)empty_zero_page,
302 PAGE_SIZE);
303 sc->result = GOOD;
304 break;
305
306 case START_STOP:
307 printk(KERN_ERR "START_STOP\n");
308 break;
309
310 default:
311 panic("simscsi: unknown SCSI command %u\n", sc->cmnd[0]);
312 }
313 }
314 if (sc->result == DID_BAD_TARGET) {
315 sc->result |= DRIVER_SENSE << 24;
316 sc->sense_buffer[0] = 0x70;
317 sc->sense_buffer[2] = 0x00;
318 }
319 if (atomic_read(&num_reqs) >= SIMSCSI_REQ_QUEUE_LEN) {
320 panic("Attempt to queue command while command is pending!!");
321 }
322 atomic_inc(&num_reqs);
323 queue[wr].sc = sc;
324 wr = (wr + 1) % SIMSCSI_REQ_QUEUE_LEN;
325
326 tasklet_schedule(&simscsi_tasklet);
327 return 0;
328 }
329
DEF_SCSI_QCMD(simscsi_queuecommand)330 static DEF_SCSI_QCMD(simscsi_queuecommand)
331
332 static int
333 simscsi_host_reset (struct scsi_cmnd *sc)
334 {
335 printk(KERN_ERR "simscsi_host_reset: not implemented\n");
336 return 0;
337 }
338
339 static struct scsi_host_template driver_template = {
340 .name = "simulated SCSI host adapter",
341 .proc_name = "simscsi",
342 .queuecommand = simscsi_queuecommand,
343 .eh_host_reset_handler = simscsi_host_reset,
344 .bios_param = simscsi_biosparam,
345 .can_queue = SIMSCSI_REQ_QUEUE_LEN,
346 .this_id = -1,
347 .sg_tablesize = SG_ALL,
348 .max_sectors = 1024,
349 .cmd_per_lun = SIMSCSI_REQ_QUEUE_LEN,
350 .use_clustering = DISABLE_CLUSTERING,
351 };
352
353 static int __init
simscsi_init(void)354 simscsi_init(void)
355 {
356 int error;
357
358 host = scsi_host_alloc(&driver_template, 0);
359 if (!host)
360 return -ENOMEM;
361
362 error = scsi_add_host(host, NULL);
363 if (error)
364 goto free_host;
365 scsi_scan_host(host);
366 return 0;
367
368 free_host:
369 scsi_host_put(host);
370 return error;
371 }
372 device_initcall(simscsi_init);
373