1 /*
2 * Simulated SCSI driver.
3 *
4 * Copyright (C) 1999, 2001-2003 Hewlett-Packard Co
5 * David Mosberger-Tang <davidm@hpl.hp.com>
6 * Stephane Eranian <eranian@hpl.hp.com>
7 *
8 * 02/01/15 David Mosberger Updated for v2.5.1
9 * 99/12/18 David Mosberger Added support for READ10/WRITE10 needed by linux v2.3.33
10 */
11 #include <linux/blkdev.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/kernel.h>
15 #include <linux/timer.h>
16 #include <asm/irq.h>
17 #include "hpsim_ssc.h"
18
19 #include <scsi/scsi.h>
20 #include <scsi/scsi_cmnd.h>
21 #include <scsi/scsi_device.h>
22 #include <scsi/scsi_host.h>
23
24 #define DEBUG_SIMSCSI 0
25
26 #define SIMSCSI_REQ_QUEUE_LEN 64
27 #define DEFAULT_SIMSCSI_ROOT "/var/ski-disks/sd"
28
29 /* Simulator system calls: */
30
31 #define SSC_OPEN 50
32 #define SSC_CLOSE 51
33 #define SSC_READ 52
34 #define SSC_WRITE 53
35 #define SSC_GET_COMPLETION 54
36 #define SSC_WAIT_COMPLETION 55
37
38 #define SSC_WRITE_ACCESS 2
39 #define SSC_READ_ACCESS 1
40
41 #if DEBUG_SIMSCSI
42 int simscsi_debug;
43 # define DBG simscsi_debug
44 #else
45 # define DBG 0
46 #endif
47
48 static struct Scsi_Host *host;
49
50 static void simscsi_interrupt (unsigned long val);
51 static DECLARE_TASKLET(simscsi_tasklet, simscsi_interrupt, 0);
52
53 struct disk_req {
54 unsigned long addr;
55 unsigned len;
56 };
57
58 struct disk_stat {
59 int fd;
60 unsigned count;
61 };
62
63 static int desc[16] = {
64 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
65 };
66
67 static struct queue_entry {
68 struct scsi_cmnd *sc;
69 } queue[SIMSCSI_REQ_QUEUE_LEN];
70
71 static int rd, wr;
72 static atomic_t num_reqs = ATOMIC_INIT(0);
73
74 /* base name for default disks */
75 static char *simscsi_root = DEFAULT_SIMSCSI_ROOT;
76
77 #define MAX_ROOT_LEN 128
78
79 /*
80 * used to setup a new base for disk images
81 * to use /foo/bar/disk[a-z] as disk images
82 * you have to specify simscsi=/foo/bar/disk on the command line
83 */
84 static int __init
simscsi_setup(char * s)85 simscsi_setup (char *s)
86 {
87 /* XXX Fix me we may need to strcpy() ? */
88 if (strlen(s) > MAX_ROOT_LEN) {
89 printk(KERN_ERR "simscsi_setup: prefix too long---using default %s\n",
90 simscsi_root);
91 }
92 simscsi_root = s;
93 return 1;
94 }
95
96 __setup("simscsi=", simscsi_setup);
97
98 static void
simscsi_interrupt(unsigned long val)99 simscsi_interrupt (unsigned long val)
100 {
101 struct scsi_cmnd *sc;
102
103 while ((sc = queue[rd].sc) != NULL) {
104 atomic_dec(&num_reqs);
105 queue[rd].sc = NULL;
106 if (DBG)
107 printk("simscsi_interrupt: done with %ld\n", sc->serial_number);
108 (*sc->scsi_done)(sc);
109 rd = (rd + 1) % SIMSCSI_REQ_QUEUE_LEN;
110 }
111 }
112
113 static int
simscsi_biosparam(struct scsi_device * sdev,struct block_device * n,sector_t capacity,int ip[])114 simscsi_biosparam (struct scsi_device *sdev, struct block_device *n,
115 sector_t capacity, int ip[])
116 {
117 ip[0] = 64; /* heads */
118 ip[1] = 32; /* sectors */
119 ip[2] = capacity >> 11; /* cylinders */
120 return 0;
121 }
122
123 static void
simscsi_sg_readwrite(struct scsi_cmnd * sc,int mode,unsigned long offset)124 simscsi_sg_readwrite (struct scsi_cmnd *sc, int mode, unsigned long offset)
125 {
126 int i;
127 struct scatterlist *sl;
128 struct disk_stat stat;
129 struct disk_req req;
130
131 stat.fd = desc[sc->device->id];
132
133 scsi_for_each_sg(sc, sl, scsi_sg_count(sc), i) {
134 req.addr = __pa(sg_virt(sl));
135 req.len = sl->length;
136 if (DBG)
137 printk("simscsi_sg_%s @ %lx (off %lx) use_sg=%d len=%d\n",
138 mode == SSC_READ ? "read":"write", req.addr, offset,
139 scsi_sg_count(sc) - i, sl->length);
140 ia64_ssc(stat.fd, 1, __pa(&req), offset, mode);
141 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
142
143 /* should not happen in our case */
144 if (stat.count != req.len) {
145 sc->result = DID_ERROR << 16;
146 return;
147 }
148 offset += sl->length;
149 }
150 sc->result = GOOD;
151 }
152
153 /*
154 * function handling both READ_6/WRITE_6 (non-scatter/gather mode)
155 * commands.
156 * Added 02/26/99 S.Eranian
157 */
158 static void
simscsi_readwrite6(struct scsi_cmnd * sc,int mode)159 simscsi_readwrite6 (struct scsi_cmnd *sc, int mode)
160 {
161 unsigned long offset;
162
163 offset = (((sc->cmnd[1] & 0x1f) << 16) | (sc->cmnd[2] << 8) | sc->cmnd[3])*512;
164 simscsi_sg_readwrite(sc, mode, offset);
165 }
166
167 static size_t
simscsi_get_disk_size(int fd)168 simscsi_get_disk_size (int fd)
169 {
170 struct disk_stat stat;
171 size_t bit, sectors = 0;
172 struct disk_req req;
173 char buf[512];
174
175 /*
176 * This is a bit kludgey: the simulator doesn't provide a
177 * direct way of determining the disk size, so we do a binary
178 * search, assuming a maximum disk size of 128GB.
179 */
180 for (bit = (128UL << 30)/512; bit != 0; bit >>= 1) {
181 req.addr = __pa(&buf);
182 req.len = sizeof(buf);
183 ia64_ssc(fd, 1, __pa(&req), ((sectors | bit) - 1)*512, SSC_READ);
184 stat.fd = fd;
185 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
186 if (stat.count == sizeof(buf))
187 sectors |= bit;
188 }
189 return sectors - 1; /* return last valid sector number */
190 }
191
192 static void
simscsi_readwrite10(struct scsi_cmnd * sc,int mode)193 simscsi_readwrite10 (struct scsi_cmnd *sc, int mode)
194 {
195 unsigned long offset;
196
197 offset = (((unsigned long)sc->cmnd[2] << 24)
198 | ((unsigned long)sc->cmnd[3] << 16)
199 | ((unsigned long)sc->cmnd[4] << 8)
200 | ((unsigned long)sc->cmnd[5] << 0))*512UL;
201 simscsi_sg_readwrite(sc, mode, offset);
202 }
203
204 static int
simscsi_queuecommand_lck(struct scsi_cmnd * sc,void (* done)(struct scsi_cmnd *))205 simscsi_queuecommand_lck (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
206 {
207 unsigned int target_id = sc->device->id;
208 char fname[MAX_ROOT_LEN+16];
209 size_t disk_size;
210 char *buf;
211 char localbuf[36];
212 #if DEBUG_SIMSCSI
213 register long sp asm ("sp");
214
215 if (DBG)
216 printk("simscsi_queuecommand: target=%d,cmnd=%u,sc=%lu,sp=%lx,done=%p\n",
217 target_id, sc->cmnd[0], sc->serial_number, sp, done);
218 #endif
219
220 sc->result = DID_BAD_TARGET << 16;
221 sc->scsi_done = done;
222 if (target_id <= 15 && sc->device->lun == 0) {
223 switch (sc->cmnd[0]) {
224 case INQUIRY:
225 if (scsi_bufflen(sc) < 35) {
226 break;
227 }
228 sprintf (fname, "%s%c", simscsi_root, 'a' + target_id);
229 desc[target_id] = ia64_ssc(__pa(fname), SSC_READ_ACCESS|SSC_WRITE_ACCESS,
230 0, 0, SSC_OPEN);
231 if (desc[target_id] < 0) {
232 /* disk doesn't exist... */
233 break;
234 }
235 buf = localbuf;
236 buf[0] = 0; /* magnetic disk */
237 buf[1] = 0; /* not a removable medium */
238 buf[2] = 2; /* SCSI-2 compliant device */
239 buf[3] = 2; /* SCSI-2 response data format */
240 buf[4] = 31; /* additional length (bytes) */
241 buf[5] = 0; /* reserved */
242 buf[6] = 0; /* reserved */
243 buf[7] = 0; /* various flags */
244 memcpy(buf + 8, "HP SIMULATED DISK 0.00", 28);
245 scsi_sg_copy_from_buffer(sc, buf, 36);
246 sc->result = GOOD;
247 break;
248
249 case TEST_UNIT_READY:
250 sc->result = GOOD;
251 break;
252
253 case READ_6:
254 if (desc[target_id] < 0 )
255 break;
256 simscsi_readwrite6(sc, SSC_READ);
257 break;
258
259 case READ_10:
260 if (desc[target_id] < 0 )
261 break;
262 simscsi_readwrite10(sc, SSC_READ);
263 break;
264
265 case WRITE_6:
266 if (desc[target_id] < 0)
267 break;
268 simscsi_readwrite6(sc, SSC_WRITE);
269 break;
270
271 case WRITE_10:
272 if (desc[target_id] < 0)
273 break;
274 simscsi_readwrite10(sc, SSC_WRITE);
275 break;
276
277 case READ_CAPACITY:
278 if (desc[target_id] < 0 || scsi_bufflen(sc) < 8) {
279 break;
280 }
281 buf = localbuf;
282 disk_size = simscsi_get_disk_size(desc[target_id]);
283
284 buf[0] = (disk_size >> 24) & 0xff;
285 buf[1] = (disk_size >> 16) & 0xff;
286 buf[2] = (disk_size >> 8) & 0xff;
287 buf[3] = (disk_size >> 0) & 0xff;
288 /* set block size of 512 bytes: */
289 buf[4] = 0;
290 buf[5] = 0;
291 buf[6] = 2;
292 buf[7] = 0;
293 scsi_sg_copy_from_buffer(sc, buf, 8);
294 sc->result = GOOD;
295 break;
296
297 case MODE_SENSE:
298 case MODE_SENSE_10:
299 /* sd.c uses this to determine whether disk does write-caching. */
300 scsi_sg_copy_from_buffer(sc, (char *)empty_zero_page,
301 PAGE_SIZE);
302 sc->result = GOOD;
303 break;
304
305 case START_STOP:
306 printk(KERN_ERR "START_STOP\n");
307 break;
308
309 default:
310 panic("simscsi: unknown SCSI command %u\n", sc->cmnd[0]);
311 }
312 }
313 if (sc->result == DID_BAD_TARGET) {
314 sc->result |= DRIVER_SENSE << 24;
315 sc->sense_buffer[0] = 0x70;
316 sc->sense_buffer[2] = 0x00;
317 }
318 if (atomic_read(&num_reqs) >= SIMSCSI_REQ_QUEUE_LEN) {
319 panic("Attempt to queue command while command is pending!!");
320 }
321 atomic_inc(&num_reqs);
322 queue[wr].sc = sc;
323 wr = (wr + 1) % SIMSCSI_REQ_QUEUE_LEN;
324
325 tasklet_schedule(&simscsi_tasklet);
326 return 0;
327 }
328
DEF_SCSI_QCMD(simscsi_queuecommand)329 static DEF_SCSI_QCMD(simscsi_queuecommand)
330
331 static int
332 simscsi_host_reset (struct scsi_cmnd *sc)
333 {
334 printk(KERN_ERR "simscsi_host_reset: not implemented\n");
335 return 0;
336 }
337
338 static struct scsi_host_template driver_template = {
339 .name = "simulated SCSI host adapter",
340 .proc_name = "simscsi",
341 .queuecommand = simscsi_queuecommand,
342 .eh_host_reset_handler = simscsi_host_reset,
343 .bios_param = simscsi_biosparam,
344 .can_queue = SIMSCSI_REQ_QUEUE_LEN,
345 .this_id = -1,
346 .sg_tablesize = SG_ALL,
347 .max_sectors = 1024,
348 .cmd_per_lun = SIMSCSI_REQ_QUEUE_LEN,
349 .use_clustering = DISABLE_CLUSTERING,
350 };
351
352 static int __init
simscsi_init(void)353 simscsi_init(void)
354 {
355 int error;
356
357 host = scsi_host_alloc(&driver_template, 0);
358 if (!host)
359 return -ENOMEM;
360
361 error = scsi_add_host(host, NULL);
362 if (error)
363 goto free_host;
364 scsi_scan_host(host);
365 return 0;
366
367 free_host:
368 scsi_host_put(host);
369 return error;
370 }
371
372 static void __exit
simscsi_exit(void)373 simscsi_exit(void)
374 {
375 scsi_remove_host(host);
376 scsi_host_put(host);
377 }
378
379 module_init(simscsi_init);
380 module_exit(simscsi_exit);
381