aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ia64/hp/sim/simscsi.c
blob: 4552a1cf5b338f5a7aa2f03175a07a6cd5f35959 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
/*
 * Simulated SCSI driver.
 *
 * Copyright (C) 1999, 2001-2003 Hewlett-Packard Co
 *	David Mosberger-Tang <davidm@hpl.hp.com>
 *	Stephane Eranian <eranian@hpl.hp.com>
 *
 * 02/01/15 David Mosberger	Updated for v2.5.1
 * 99/12/18 David Mosberger	Added support for READ10/WRITE10 needed by linux v2.3.33
 */
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <asm/irq.h>
#include "hpsim_ssc.h"

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#define DEBUG_SIMSCSI	0

#define SIMSCSI_REQ_QUEUE_LEN	64
#define DEFAULT_SIMSCSI_ROOT	"/var/ski-disks/sd"

/* Simulator system calls: */

#define SSC_OPEN			50
#define SSC_CLOSE			51
#define SSC_READ			52
#define SSC_WRITE			53
#define SSC_GET_COMPLETION		54
#define SSC_WAIT_COMPLETION		55

#define SSC_WRITE_ACCESS		2
#define SSC_READ_ACCESS			1

#if DEBUG_SIMSCSI
  int simscsi_debug;
# define DBG	simscsi_debug
#else
# define DBG	0
#endif

static struct Scsi_Host *host;

static void simscsi_interrupt (unsigned long val);
static DECLARE_TASKLET(simscsi_tasklet, simscsi_interrupt, 0);

struct disk_req {
	unsigned long addr;
	unsigned len;
};

struct disk_stat {
	int fd;
	unsigned count;
};

static int desc[16] = {
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
};

static struct queue_entry {
	struct scsi_cmnd *sc;
} queue[SIMSCSI_REQ_QUEUE_LEN];

static int rd, wr;
static atomic_t num_reqs = ATOMIC_INIT(0);

/* base name for default disks */
static char *simscsi_root = DEFAULT_SIMSCSI_ROOT;

#define MAX_ROOT_LEN	128

/*
 * used to setup a new base for disk images
 * to use /foo/bar/disk[a-z] as disk images
 * you have to specify simscsi=/foo/bar/disk on the command line
 */
static int __init
simscsi_setup (char *s)
{
	/* XXX Fix me we may need to strcpy() ? */
	if (strlen(s) > MAX_ROOT_LEN) {
		printk(KERN_ERR "simscsi_setup: prefix too long---using default %s\n",
		       simscsi_root);
	}
	simscsi_root = s;
	return 1;
}

__setup("simscsi=", simscsi_setup);

static void
simscsi_interrupt (unsigned long val)
{
	struct scsi_cmnd *sc;

	while ((sc = queue[rd].sc) != NULL) {
		atomic_dec(&num_reqs);
		queue[rd].sc = NULL;
		if (DBG)
			printk("simscsi_interrupt: done with %ld\n", sc->serial_number);
		(*sc->scsi_done)(sc);
		rd = (rd + 1) % SIMSCSI_REQ_QUEUE_LEN;
	}
}

static int
simscsi_biosparam (struct scsi_device *sdev, struct block_device *n,
		sector_t capacity, int ip[])
{
	ip[0] = 64;		/* heads */
	ip[1] = 32;		/* sectors */
	ip[2] = capacity >> 11;	/* cylinders */
	return 0;
}

static void
simscsi_sg_readwrite (struct scsi_cmnd *sc, int mode, unsigned long offset)
{
	int i;
	struct scatterlist *sl;
	struct disk_stat stat;
	struct disk_req req;

	stat.fd = desc[sc->device->id];

	scsi_for_each_sg(sc, sl, scsi_sg_count(sc), i) {
		req.addr = __pa(page_address(sl->page) + sl->offset);
		req.len  = sl->length;
		if (DBG)
			printk("simscsi_sg_%s @ %lx (off %lx) use_sg=%d len=%d\n",
			       mode == SSC_READ ? "read":"write", req.addr, offset,
			       scsi_sg_count(sc) - i, sl->length);
		ia64_ssc(stat.fd, 1, __pa(&req), offset, mode);
		ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);

		/* should not happen in our case */
		if (stat.count != req.len) {
			sc->result = DID_ERROR << 16;
			return;
		}
		offset +=  sl->length;
	}
	sc->result = GOOD;
}

/*
 * function handling both READ_6/WRITE_6 (non-scatter/gather mode)
 * commands.
 * Added 02/26/99 S.Eranian
 */
static void
simscsi_readwrite6 (struct scsi_cmnd *sc, int mode)
{
	unsigned long offset;

	offset = (((sc->cmnd[1] & 0x1f) << 16) | (sc->cmnd[2] << 8) | sc->cmnd[3])*512;
	simscsi_sg_readwrite(sc, mode, offset);
}

static size_t
simscsi_get_disk_size (int fd)
{
	struct disk_stat stat;
	size_t bit, sectors = 0;
	struct disk_req req;
	char buf[512];

	/*
	 * This is a bit kludgey: the simulator doesn't provide a
	 * direct way of determining the disk size, so we do a binary
	 * search, assuming a maximum disk size of 128GB.
	 */
	for (bit = (128UL << 30)/512; bit != 0; bit >>= 1) {
		req.addr = __pa(&buf);
		req.len = sizeof(buf);
		ia64_ssc(fd, 1, __pa(&req), ((sectors | bit) - 1)*512, SSC_READ);
		stat.fd = fd;
		ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
		if (stat.count == sizeof(buf))
			sectors |= bit;
	}
	return sectors - 1;	/* return last valid sector number */
}

static void
simscsi_readwrite10 (struct scsi_cmnd *sc, int mode)
{
	unsigned long offset;

	offset = (((unsigned long)sc->cmnd[2] << 24) 
		| ((unsigned long)sc->cmnd[3] << 16)
		| ((unsigned long)sc->cmnd[4] <<  8) 
		| ((unsigned long)sc->cmnd[5] <<  0))*512UL;
	simscsi_sg_readwrite(sc, mode, offset);
}

static void simscsi_fillresult(struct scsi_cmnd *sc, char *buf, unsigned len)
{

	int i;
	unsigned thislen;
	struct scatterlist *slp;

	scsi_for_each_sg(sc, slp, scsi_sg_count(sc), i) {
		if (!len)
			break;
		thislen = min(len, slp->length);
		memcpy(page_address(slp->page) + slp->offset, buf, thislen);
		len -= thislen;
	}
}

static int
simscsi_queuecommand (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
{
	unsigned int target_id = sc->device->id;
	char fname[MAX_ROOT_LEN+16];
	size_t disk_size;
	char *buf;
	char localbuf[36];
#if DEBUG_SIMSCSI
	register long sp asm ("sp");

	if (DBG)
		printk("simscsi_queuecommand: target=%d,cmnd=%u,sc=%lu,sp=%lx,done=%p\n",
		       target_id, sc->cmnd[0], sc->serial_number, sp, done);
#endif

	sc->result = DID_BAD_TARGET << 16;
	sc->scsi_done = done;
	if (target_id <= 15 && sc->device->lun == 0) {
		switch (sc->cmnd[0]) {
		      case INQUIRY:
			if (scsi_bufflen(sc) < 35) {
				break;
			}
			sprintf (fname, "%s%c", simscsi_root, 'a' + target_id);
			desc[target_id] = ia64_ssc(__pa(fname), SSC_READ_ACCESS|SSC_WRITE_ACCESS,
						   0, 0, SSC_OPEN);
			if (desc[target_id] < 0) {
				/* disk doesn't exist... */
				break;
			}
			buf = localbuf;
			buf[0] = 0;	/* magnetic disk */
			buf[1] = 0;	/* not a removable medium */
			buf[2] = 2;	/* SCSI-2 compliant device */
			buf[3] = 2;	/* SCSI-2 response data format */
			buf[4] = 31;	/* additional length (bytes) */
			buf[5] = 0;	/* reserved */
			buf[6] = 0;	/* reserved */
			buf[7] = 0;	/* various flags */
			memcpy(buf + 8, "HP      SIMULATED DISK  0.00",  28);
			simscsi_fillresult(sc, buf, 36);
			sc->result = GOOD;
			break;

		      case TEST_UNIT_READY:
			sc->result = GOOD;
			break;

		      case READ_6:
			if (desc[target_id] < 0 )
				break;
			simscsi_readwrite6(sc, SSC_READ);
			break;

		      case READ_10:
			if (desc[target_id] < 0 )
				break;
			simscsi_readwrite10(sc, SSC_READ);
			break;

		      case WRITE_6:
			if (desc[target_id] < 0)
				break;
			simscsi_readwrite6(sc, SSC_WRITE);
			break;

		      case WRITE_10:
			if (desc[target_id] < 0)
				break;
			simscsi_readwrite10(sc, SSC_WRITE);
			break;

		      case READ_CAPACITY:
			if (desc[target_id] < 0 || scsi_bufflen(sc) < 8) {
				break;
			}
			buf = localbuf;
			disk_size = simscsi_get_disk_size(desc[target_id]);

			buf[0] = (disk_size >> 24) & 0xff;
			buf[1] = (disk_size >> 16) & 0xff;
			buf[2] = (disk_size >>  8) & 0xff;
			buf[3] = (disk_size >>  0) & 0xff;
			/* set block size of 512 bytes: */
			buf[4] = 0;
			buf[5] = 0;
			buf[6] = 2;
			buf[7] = 0;
			simscsi_fillresult(sc, buf, 8);
			sc->result = GOOD;
			break;

		      case MODE_SENSE:
		      case MODE_SENSE_10:
			/* sd.c uses this to determine whether disk does write-caching. */
			simscsi_fillresult(sc, (char *)empty_zero_page, scsi_bufflen(sc));
			sc->result = GOOD;
			break;

		      case START_STOP:
			printk(KERN_ERR "START_STOP\n");
			break;

		      default:
			panic("simscsi: unknown SCSI command %u\n", sc->cmnd[0]);
		}
	}
	if (sc->result == DID_BAD_TARGET) {
		sc->result |= DRIVER_SENSE << 24;
		sc->sense_buffer[0] = 0x70;
		sc->sense_buffer[2] = 0x00;
	}
	if (atomic_read(&num_reqs) >= SIMSCSI_REQ_QUEUE_LEN) {
		panic("Attempt to queue command while command is pending!!");
	}
	atomic_inc(&num_reqs);
	queue[wr].sc = sc;
	wr = (wr + 1) % SIMSCSI_REQ_QUEUE_LEN;

	tasklet_schedule(&simscsi_tasklet);
	return 0;
}

static int
simscsi_host_reset (struct scsi_cmnd *sc)
{
	printk(KERN_ERR "simscsi_host_reset: not implemented\n");
	return 0;
}

static struct scsi_host_template driver_template = {
	.name			= "simulated SCSI host adapter",
	.proc_name		= "simscsi",
	.queuecommand		= simscsi_queuecommand,
	.eh_host_reset_handler	= simscsi_host_reset,
	.bios_param		= simscsi_biosparam,
	.can_queue		= SIMSCSI_REQ_QUEUE_LEN,
	.this_id		= -1,
	.sg_tablesize		= SG_ALL,
	.max_sectors		= 1024,
	.cmd_per_lun		= SIMSCSI_REQ_QUEUE_LEN,
	.use_clustering		= DISABLE_CLUSTERING,
};

static int __init
simscsi_init(void)
{
	int error;

	host = scsi_host_alloc(&driver_template, 0);
	if (!host)
		return -ENOMEM;

	error = scsi_add_host(host, NULL);
	if (!error)
		scsi_scan_host(host);
	return error;
}

static void __exit
simscsi_exit(void)
{
	scsi_remove_host(host);
	scsi_host_put(host);
}

module_init(simscsi_init);
module_exit(simscsi_exit);