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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
18#include <scsi/scsi.h>
19#include <scsi/scsi_cmnd.h>
20#include <scsi/scsi_device.h>
21#include <scsi/scsi_host.h>
22
23#define DEBUG_SIMSCSI 0
24
25#define SIMSCSI_REQ_QUEUE_LEN 64
26#define DEFAULT_SIMSCSI_ROOT "/var/ski-disks/sd"
27
28
29
30#define SSC_OPEN 50
31#define SSC_CLOSE 51
32#define SSC_READ 52
33#define SSC_WRITE 53
34#define SSC_GET_COMPLETION 54
35#define SSC_WAIT_COMPLETION 55
36
37#define SSC_WRITE_ACCESS 2
38#define SSC_READ_ACCESS 1
39
40#if DEBUG_SIMSCSI
41 int simscsi_debug;
42# define DBG simscsi_debug
43#else
44# define DBG 0
45#endif
46
47static struct Scsi_Host *host;
48
49static void simscsi_interrupt (unsigned long val);
50static DECLARE_TASKLET(simscsi_tasklet, simscsi_interrupt, 0);
51
52struct disk_req {
53 unsigned long addr;
54 unsigned len;
55};
56
57struct disk_stat {
58 int fd;
59 unsigned count;
60};
61
62extern long ia64_ssc (long arg0, long arg1, long arg2, long arg3, int nr);
63
64static int desc[16] = {
65 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
66};
67
68static struct queue_entry {
69 struct scsi_cmnd *sc;
70} queue[SIMSCSI_REQ_QUEUE_LEN];
71
72static int rd, wr;
73static atomic_t num_reqs = ATOMIC_INIT(0);
74
75
76static char *simscsi_root = DEFAULT_SIMSCSI_ROOT;
77
78#define MAX_ROOT_LEN 128
79
80
81
82
83
84
85static int __init
86simscsi_setup (char *s)
87{
88
89 if (strlen(s) > MAX_ROOT_LEN) {
90 printk(KERN_ERR "simscsi_setup: prefix too long---using default %s\n",
91 simscsi_root);
92 }
93 simscsi_root = s;
94 return 1;
95}
96
97__setup("simscsi=", simscsi_setup);
98
99static void
100simscsi_interrupt (unsigned long val)
101{
102 struct scsi_cmnd *sc;
103
104 while ((sc = queue[rd].sc) != 0) {
105 atomic_dec(&num_reqs);
106 queue[rd].sc = 0;
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
114static int
115simscsi_biosparam (struct scsi_device *sdev, struct block_device *n,
116 sector_t capacity, int ip[])
117{
118 ip[0] = 64;
119 ip[1] = 32;
120 ip[2] = capacity >> 11;
121 return 0;
122}
123
124static void
125simscsi_readwrite (struct scsi_cmnd *sc, int mode, unsigned long offset, unsigned long len)
126{
127 struct disk_stat stat;
128 struct disk_req req;
129
130 req.addr = __pa(sc->request_buffer);
131 req.len = len;
132
133 if (sc->request_bufflen < req.len)
134 return;
135
136 stat.fd = desc[sc->device->id];
137 if (DBG)
138 printk("simscsi_%s @ %lx (off %lx)\n",
139 mode == SSC_READ ? "read":"write", req.addr, offset);
140 ia64_ssc(stat.fd, 1, __pa(&req), offset, mode);
141 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
142
143 if (stat.count == req.len) {
144 sc->result = GOOD;
145 } else {
146 sc->result = DID_ERROR << 16;
147 }
148}
149
150static void
151simscsi_sg_readwrite (struct scsi_cmnd *sc, int mode, unsigned long offset)
152{
153 int list_len = sc->use_sg;
154 struct scatterlist *sl = (struct scatterlist *)sc->buffer;
155 struct disk_stat stat;
156 struct disk_req req;
157
158 stat.fd = desc[sc->device->id];
159
160 while (list_len) {
161 req.addr = __pa(page_address(sl->page) + sl->offset);
162 req.len = sl->length;
163 if (DBG)
164 printk("simscsi_sg_%s @ %lx (off %lx) use_sg=%d len=%d\n",
165 mode == SSC_READ ? "read":"write", req.addr, offset,
166 list_len, sl->length);
167 ia64_ssc(stat.fd, 1, __pa(&req), offset, mode);
168 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
169
170
171 if (stat.count != req.len) {
172 sc->result = DID_ERROR << 16;
173 return;
174 }
175 offset += sl->length;
176 sl++;
177 list_len--;
178 }
179 sc->result = GOOD;
180}
181
182
183
184
185
186
187static void
188simscsi_readwrite6 (struct scsi_cmnd *sc, int mode)
189{
190 unsigned long offset;
191
192 offset = (((sc->cmnd[1] & 0x1f) << 16) | (sc->cmnd[2] << 8) | sc->cmnd[3])*512;
193 if (sc->use_sg > 0)
194 simscsi_sg_readwrite(sc, mode, offset);
195 else
196 simscsi_readwrite(sc, mode, offset, sc->cmnd[4]*512);
197}
198
199static size_t
200simscsi_get_disk_size (int fd)
201{
202 struct disk_stat stat;
203 size_t bit, sectors = 0;
204 struct disk_req req;
205 char buf[512];
206
207
208
209
210
211 for (bit = (4UL << 30)/512; bit != 0; bit >>= 1) {
212 req.addr = __pa(&buf);
213 req.len = sizeof(buf);
214 ia64_ssc(fd, 1, __pa(&req), ((sectors | bit) - 1)*512, SSC_READ);
215 stat.fd = fd;
216 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
217 if (stat.count == sizeof(buf))
218 sectors |= bit;
219 }
220 return sectors - 1;
221}
222
223static void
224simscsi_readwrite10 (struct scsi_cmnd *sc, int mode)
225{
226 unsigned long offset;
227
228 offset = ( (sc->cmnd[2] << 24) | (sc->cmnd[3] << 16)
229 | (sc->cmnd[4] << 8) | (sc->cmnd[5] << 0))*512;
230 if (sc->use_sg > 0)
231 simscsi_sg_readwrite(sc, mode, offset);
232 else
233 simscsi_readwrite(sc, mode, offset, ((sc->cmnd[7] << 8) | sc->cmnd[8])*512);
234}
235
236static int
237simscsi_queuecommand (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
238{
239 unsigned int target_id = sc->device->id;
240 char fname[MAX_ROOT_LEN+16];
241 size_t disk_size;
242 char *buf;
243#if DEBUG_SIMSCSI
244 register long sp asm ("sp");
245
246 if (DBG)
247 printk("simscsi_queuecommand: target=%d,cmnd=%u,sc=%lu,sp=%lx,done=%p\n",
248 target_id, sc->cmnd[0], sc->serial_number, sp, done);
249#endif
250
251 sc->result = DID_BAD_TARGET << 16;
252 sc->scsi_done = done;
253 if (target_id <= 15 && sc->device->lun == 0) {
254 switch (sc->cmnd[0]) {
255 case INQUIRY:
256 if (sc->request_bufflen < 35) {
257 break;
258 }
259 sprintf (fname, "%s%c", simscsi_root, 'a' + target_id);
260 desc[target_id] = ia64_ssc(__pa(fname), SSC_READ_ACCESS|SSC_WRITE_ACCESS,
261 0, 0, SSC_OPEN);
262 if (desc[target_id] < 0) {
263
264 break;
265 }
266 buf = sc->request_buffer;
267 buf[0] = 0;
268 buf[1] = 0;
269 buf[2] = 2;
270 buf[3] = 2;
271 buf[4] = 31;
272 buf[5] = 0;
273 buf[6] = 0;
274 buf[7] = 0;
275 memcpy(buf + 8, "HP SIMULATED DISK 0.00", 28);
276 sc->result = GOOD;
277 break;
278
279 case TEST_UNIT_READY:
280 sc->result = GOOD;
281 break;
282
283 case READ_6:
284 if (desc[target_id] < 0 )
285 break;
286 simscsi_readwrite6(sc, SSC_READ);
287 break;
288
289 case READ_10:
290 if (desc[target_id] < 0 )
291 break;
292 simscsi_readwrite10(sc, SSC_READ);
293 break;
294
295 case WRITE_6:
296 if (desc[target_id] < 0)
297 break;
298 simscsi_readwrite6(sc, SSC_WRITE);
299 break;
300
301 case WRITE_10:
302 if (desc[target_id] < 0)
303 break;
304 simscsi_readwrite10(sc, SSC_WRITE);
305 break;
306
307
308 case READ_CAPACITY:
309 if (desc[target_id] < 0 || sc->request_bufflen < 8) {
310 break;
311 }
312 buf = sc->request_buffer;
313
314 disk_size = simscsi_get_disk_size(desc[target_id]);
315
316
317 buf[0] = (disk_size >> 24) & 0xff;
318 buf[1] = (disk_size >> 16) & 0xff;
319 buf[2] = (disk_size >> 8) & 0xff;
320 buf[3] = (disk_size >> 0) & 0xff;
321
322 buf[4] = 0;
323 buf[5] = 0;
324 buf[6] = 2;
325 buf[7] = 0;
326 sc->result = GOOD;
327 break;
328
329 case MODE_SENSE:
330 case MODE_SENSE_10:
331
332 memset(sc->request_buffer, 0, 128);
333 sc->result = GOOD;
334 break;
335
336 case START_STOP:
337 printk(KERN_ERR "START_STOP\n");
338 break;
339
340 default:
341 panic("simscsi: unknown SCSI command %u\n", sc->cmnd[0]);
342 }
343 }
344 if (sc->result == DID_BAD_TARGET) {
345 sc->result |= DRIVER_SENSE << 24;
346 sc->sense_buffer[0] = 0x70;
347 sc->sense_buffer[2] = 0x00;
348 }
349 if (atomic_read(&num_reqs) >= SIMSCSI_REQ_QUEUE_LEN) {
350 panic("Attempt to queue command while command is pending!!");
351 }
352 atomic_inc(&num_reqs);
353 queue[wr].sc = sc;
354 wr = (wr + 1) % SIMSCSI_REQ_QUEUE_LEN;
355
356 tasklet_schedule(&simscsi_tasklet);
357 return 0;
358}
359
360static int
361simscsi_host_reset (struct scsi_cmnd *sc)
362{
363 printk(KERN_ERR "simscsi_host_reset: not implemented\n");
364 return 0;
365}
366
367static struct scsi_host_template driver_template = {
368 .name = "simulated SCSI host adapter",
369 .proc_name = "simscsi",
370 .queuecommand = simscsi_queuecommand,
371 .eh_host_reset_handler = simscsi_host_reset,
372 .bios_param = simscsi_biosparam,
373 .can_queue = SIMSCSI_REQ_QUEUE_LEN,
374 .this_id = -1,
375 .sg_tablesize = SG_ALL,
376 .max_sectors = 1024,
377 .cmd_per_lun = SIMSCSI_REQ_QUEUE_LEN,
378 .use_clustering = DISABLE_CLUSTERING,
379};
380
381static int __init
382simscsi_init(void)
383{
384 int error;
385
386 host = scsi_host_alloc(&driver_template, 0);
387 if (!host)
388 return -ENOMEM;
389
390 error = scsi_add_host(host, NULL);
391 if (!error)
392 scsi_scan_host(host);
393 return error;
394}
395
396static void __exit
397simscsi_exit(void)
398{
399 scsi_remove_host(host);
400 scsi_host_put(host);
401}
402
403module_init(simscsi_init);
404module_exit(simscsi_exit);
405
