arch/ia64/hp/sim/simscsi.c

   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
  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 /* Simulator system calls: */
  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
  47 static struct Scsi_Host *host;
  48
  49 static void simscsi_interrupt (unsigned long val);
  50 static DECLARE_TASKLET(simscsi_tasklet, simscsi_interrupt, 0);
  51
  52 struct disk_req {
  53         unsigned long addr;
  54         unsigned len;
  55 };
  56
  57 struct disk_stat {
  58         int fd;
  59         unsigned count;
  60 };
  61
  62 extern long ia64_ssc (long arg0, long arg1, long arg2, long arg3, int nr);
  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
  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         }
  93         simscsi_root = s;
  94         return 1;
  95 }
  96
  97 __setup("simscsi=", simscsi_setup);
  98
  99 static void
 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
 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
 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(page_address(sl->page) + sl->offset);
 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
 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
 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
 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 void simscsi_fillresult(struct scsi_cmnd *sc, char *buf, unsigned len)
 206 {
 207
 208         int i;
 209         unsigned thislen;
 210         struct scatterlist *slp;
 211
 212         scsi_for_each_sg(sc, slp, scsi_sg_count(sc), i) {
 213                 if (!len)
 214                         break;
 215                 thislen = min(len, slp->length);
 216                 memcpy(page_address(slp->page) + slp->offset, buf, thislen);
 217                 len -= thislen;
 218         }
 219 }
 220
 221 static int
 222 simscsi_queuecommand (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
 223 {
 224         unsigned int target_id = sc->device->id;
 225         char fname[MAX_ROOT_LEN+16];
 226         size_t disk_size;
 227         char *buf;
 228         char localbuf[36];
 229 #if DEBUG_SIMSCSI
 230         register long sp asm ("sp");
 231
 232         if (DBG)
 233                 printk("simscsi_queuecommand: target=%d,cmnd=%u,sc=%lu,sp=%lx,done=%p\n",
 234                        target_id, sc->cmnd[0], sc->serial_number, sp, done);
 235 #endif
 236
 237         sc->result = DID_BAD_TARGET << 16;
 238         sc->scsi_done = done;
 239         if (target_id <= 15 && sc->device->lun == 0) {
 240                 switch (sc->cmnd[0]) {
 241                       case INQUIRY:
 242                         if (scsi_bufflen(sc) < 35) {
 243                                 break;
 244                         }
 245                         sprintf (fname, "%s%c", simscsi_root, 'a' + target_id);
 246                         desc[target_id] = ia64_ssc(__pa(fname), SSC_READ_ACCESS|SSC_WRITE_ACCESS,
 247                                                    0, 0, SSC_OPEN);
 248                         if (desc[target_id] < 0) {
 249                                 /* disk doesn't exist... */
 250                                 break;
 251                         }
 252                         buf = localbuf;
 253                         buf[0] = 0;     /* magnetic disk */
 254                         buf[1] = 0;     /* not a removable medium */
 255                         buf[2] = 2;     /* SCSI-2 compliant device */
 256                         buf[3] = 2;     /* SCSI-2 response data format */
 257                         buf[4] = 31;    /* additional length (bytes) */
 258                         buf[5] = 0;     /* reserved */
 259                         buf[6] = 0;     /* reserved */
 260                         buf[7] = 0;     /* various flags */
 261                         memcpy(buf + 8, "HP      SIMULATED DISK  0.00",  28);
 262                         simscsi_fillresult(sc, buf, 36);
 263                         sc->result = GOOD;
 264                         break;
 265
 266                       case TEST_UNIT_READY:
 267                         sc->result = GOOD;
 268                         break;
 269
 270                       case READ_6:
 271                         if (desc[target_id] < 0 )
 272                                 break;
 273                         simscsi_readwrite6(sc, SSC_READ);
 274                         break;
 275
 276                       case READ_10:
 277                         if (desc[target_id] < 0 )
 278                                 break;
 279                         simscsi_readwrite10(sc, SSC_READ);
 280                         break;
 281
 282                       case WRITE_6:
 283                         if (desc[target_id] < 0)
 284                                 break;
 285                         simscsi_readwrite6(sc, SSC_WRITE);
 286                         break;
 287
 288                       case WRITE_10:
 289                         if (desc[target_id] < 0)
 290                                 break;
 291                         simscsi_readwrite10(sc, SSC_WRITE);
 292                         break;
 293
 294                       case READ_CAPACITY:
 295                         if (desc[target_id] < 0 || scsi_bufflen(sc) < 8) {
 296                                 break;
 297                         }
 298                         buf = localbuf;
 299                         disk_size = simscsi_get_disk_size(desc[target_id]);
 300
 301                         buf[0] = (disk_size >> 24) & 0xff;
 302                         buf[1] = (disk_size >> 16) & 0xff;
 303                         buf[2] = (disk_size >>  8) & 0xff;
 304                         buf[3] = (disk_size >>  0) & 0xff;
 305                         /* set block size of 512 bytes: */
 306                         buf[4] = 0;
 307                         buf[5] = 0;
 308                         buf[6] = 2;
 309                         buf[7] = 0;
 310                         simscsi_fillresult(sc, buf, 8);
 311                         sc->result = GOOD;
 312                         break;
 313
 314                       case MODE_SENSE:
 315                       case MODE_SENSE_10:
 316                         /* sd.c uses this to determine whether disk does write-caching. */
 317                         simscsi_fillresult(sc, (char *)empty_zero_page, scsi_bufflen(sc));
 318                         sc->result = GOOD;
 319                         break;
 320
 321                       case START_STOP:
 322                         printk(KERN_ERR "START_STOP\n");
 323                         break;
 324
 325                       default:
 326                         panic("simscsi: unknown SCSI command %u\n", sc->cmnd[0]);
 327                 }
 328         }
 329         if (sc->result == DID_BAD_TARGET) {
 330                 sc->result |= DRIVER_SENSE << 24;
 331                 sc->sense_buffer[0] = 0x70;
 332                 sc->sense_buffer[2] = 0x00;
 333         }
 334         if (atomic_read(&num_reqs) >= SIMSCSI_REQ_QUEUE_LEN) {
 335                 panic("Attempt to queue command while command is pending!!");
 336         }
 337         atomic_inc(&num_reqs);
 338         queue[wr].sc = sc;
 339         wr = (wr + 1) % SIMSCSI_REQ_QUEUE_LEN;
 340
 341         tasklet_schedule(&simscsi_tasklet);
 342         return 0;
 343 }
 344
 345 static int
 346 simscsi_host_reset (struct scsi_cmnd *sc)
 347 {
 348         printk(KERN_ERR "simscsi_host_reset: not implemented\n");
 349         return 0;
 350 }
 351
 352 static struct scsi_host_template driver_template = {
 353         .name                   = "simulated SCSI host adapter",
 354         .proc_name              = "simscsi",
 355         .queuecommand           = simscsi_queuecommand,
 356         .eh_host_reset_handler  = simscsi_host_reset,
 357         .bios_param             = simscsi_biosparam,
 358         .can_queue              = SIMSCSI_REQ_QUEUE_LEN,
 359         .this_id                = -1,
 360         .sg_tablesize           = SG_ALL,
 361         .max_sectors            = 1024,
 362         .cmd_per_lun            = SIMSCSI_REQ_QUEUE_LEN,
 363         .use_clustering         = DISABLE_CLUSTERING,
 364 };
 365
 366 static int __init
 367 simscsi_init(void)
 368 {
 369         int error;
 370
 371         host = scsi_host_alloc(&driver_template, 0);
 372         if (!host)
 373                 return -ENOMEM;
 374
 375         error = scsi_add_host(host, NULL);
 376         if (error)
 377                 goto free_host;
 378         scsi_scan_host(host);
 379         return 0;
 380
 381  free_host:
 382         scsi_host_put(host);
 383         return error;
 384 }
 385
 386 static void __exit
 387 simscsi_exit(void)
 388 {
 389         scsi_remove_host(host);
 390         scsi_host_put(host);
 391 }
 392
 393 module_init(simscsi_init);
 394 module_exit(simscsi_exit);