release/src-rt-6.x.4708/linux/linux-2.6.36/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 #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
  85 simscsi_setup (char *s)
  86 {
  87         if (strlen(s) > MAX_ROOT_LEN) {
  88                 printk(KERN_ERR "simscsi_setup: prefix too long---using default %s\n",
  89                        simscsi_root);
  90         }
  91         simscsi_root = s;
  92         return 1;
  93 }
  94
  95 __setup("simscsi=", simscsi_setup);
  96
  97 static void
  98 simscsi_interrupt (unsigned long val)
  99 {
 100         struct scsi_cmnd *sc;
 101
 102         while ((sc = queue[rd].sc) != NULL) {
 103                 atomic_dec(&num_reqs);
 104                 queue[rd].sc = NULL;
 105                 if (DBG)
 106                         printk("simscsi_interrupt: done with %ld\n", sc->serial_number);
 107                 (*sc->scsi_done)(sc);
 108                 rd = (rd + 1) % SIMSCSI_REQ_QUEUE_LEN;
 109         }
 110 }
 111
 112 static int
 113 simscsi_biosparam (struct scsi_device *sdev, struct block_device *n,
 114                 sector_t capacity, int ip[])
 115 {
 116         ip[0] = 64;             /* heads */
 117         ip[1] = 32;             /* sectors */
 118         ip[2] = capacity >> 11; /* cylinders */
 119         return 0;
 120 }
 121
 122 static void
 123 simscsi_sg_readwrite (struct scsi_cmnd *sc, int mode, unsigned long offset)
 124 {
 125         int i;
 126         struct scatterlist *sl;
 127         struct disk_stat stat;
 128         struct disk_req req;
 129
 130         stat.fd = desc[sc->device->id];
 131
 132         scsi_for_each_sg(sc, sl, scsi_sg_count(sc), i) {
 133                 req.addr = __pa(sg_virt(sl));
 134                 req.len  = sl->length;
 135                 if (DBG)
 136                         printk("simscsi_sg_%s @ %lx (off %lx) use_sg=%d len=%d\n",
 137                                mode == SSC_READ ? "read":"write", req.addr, offset,
 138                                scsi_sg_count(sc) - i, sl->length);
 139                 ia64_ssc(stat.fd, 1, __pa(&req), offset, mode);
 140                 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
 141
 142                 /* should not happen in our case */
 143                 if (stat.count != req.len) {
 144                         sc->result = DID_ERROR << 16;
 145                         return;
 146                 }
 147                 offset +=  sl->length;
 148         }
 149         sc->result = GOOD;
 150 }
 151
 152 /*
 153  * function handling both READ_6/WRITE_6 (non-scatter/gather mode)
 154  * commands.
 155  * Added 02/26/99 S.Eranian
 156  */
 157 static void
 158 simscsi_readwrite6 (struct scsi_cmnd *sc, int mode)
 159 {
 160         unsigned long offset;
 161
 162         offset = (((sc->cmnd[1] & 0x1f) << 16) | (sc->cmnd[2] << 8) | sc->cmnd[3])*512;
 163         simscsi_sg_readwrite(sc, mode, offset);
 164 }
 165
 166 static size_t
 167 simscsi_get_disk_size (int fd)
 168 {
 169         struct disk_stat stat;
 170         size_t bit, sectors = 0;
 171         struct disk_req req;
 172         char buf[512];
 173
 174         /*
 175          * This is a bit kludgey: the simulator doesn't provide a
 176          * direct way of determining the disk size, so we do a binary
 177          * search, assuming a maximum disk size of 128GB.
 178          */
 179         for (bit = (128UL << 30)/512; bit != 0; bit >>= 1) {
 180                 req.addr = __pa(&buf);
 181                 req.len = sizeof(buf);
 182                 ia64_ssc(fd, 1, __pa(&req), ((sectors | bit) - 1)*512, SSC_READ);
 183                 stat.fd = fd;
 184                 ia64_ssc(__pa(&stat), 0, 0, 0, SSC_WAIT_COMPLETION);
 185                 if (stat.count == sizeof(buf))
 186                         sectors |= bit;
 187         }
 188         return sectors - 1;     /* return last valid sector number */
 189 }
 190
 191 static void
 192 simscsi_readwrite10 (struct scsi_cmnd *sc, int mode)
 193 {
 194         unsigned long offset;
 195
 196         offset = (((unsigned long)sc->cmnd[2] << 24)
 197                 | ((unsigned long)sc->cmnd[3] << 16)
 198                 | ((unsigned long)sc->cmnd[4] <<  8)
 199                 | ((unsigned long)sc->cmnd[5] <<  0))*512UL;
 200         simscsi_sg_readwrite(sc, mode, offset);
 201 }
 202
 203 static int
 204 simscsi_queuecommand (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
 205 {
 206         unsigned int target_id = sc->device->id;
 207         char fname[MAX_ROOT_LEN+16];
 208         size_t disk_size;
 209         char *buf;
 210         char localbuf[36];
 211 #if DEBUG_SIMSCSI
 212         register long sp asm ("sp");
 213
 214         if (DBG)
 215                 printk("simscsi_queuecommand: target=%d,cmnd=%u,sc=%lu,sp=%lx,done=%p\n",
 216                        target_id, sc->cmnd[0], sc->serial_number, sp, done);
 217 #endif
 218
 219         sc->result = DID_BAD_TARGET << 16;
 220         sc->scsi_done = done;
 221         if (target_id <= 15 && sc->device->lun == 0) {
 222                 switch (sc->cmnd[0]) {
 223                       case INQUIRY:
 224                         if (scsi_bufflen(sc) < 35) {
 225                                 break;
 226                         }
 227                         sprintf (fname, "%s%c", simscsi_root, 'a' + target_id);
 228                         desc[target_id] = ia64_ssc(__pa(fname), SSC_READ_ACCESS|SSC_WRITE_ACCESS,
 229                                                    0, 0, SSC_OPEN);
 230                         if (desc[target_id] < 0) {
 231                                 /* disk doesn't exist... */
 232                                 break;
 233                         }
 234                         buf = localbuf;
 235                         buf[0] = 0;     /* magnetic disk */
 236                         buf[1] = 0;     /* not a removable medium */
 237                         buf[2] = 2;     /* SCSI-2 compliant device */
 238                         buf[3] = 2;     /* SCSI-2 response data format */
 239                         buf[4] = 31;    /* additional length (bytes) */
 240                         buf[5] = 0;     /* reserved */
 241                         buf[6] = 0;     /* reserved */
 242                         buf[7] = 0;     /* various flags */
 243                         memcpy(buf + 8, "HP      SIMULATED DISK  0.00",  28);
 244                         scsi_sg_copy_from_buffer(sc, buf, 36);
 245                         sc->result = GOOD;
 246                         break;
 247
 248                       case TEST_UNIT_READY:
 249                         sc->result = GOOD;
 250                         break;
 251
 252                       case READ_6:
 253                         if (desc[target_id] < 0 )
 254                                 break;
 255                         simscsi_readwrite6(sc, SSC_READ);
 256                         break;
 257
 258                       case READ_10:
 259                         if (desc[target_id] < 0 )
 260                                 break;
 261                         simscsi_readwrite10(sc, SSC_READ);
 262                         break;
 263
 264                       case WRITE_6:
 265                         if (desc[target_id] < 0)
 266                                 break;
 267                         simscsi_readwrite6(sc, SSC_WRITE);
 268                         break;
 269
 270                       case WRITE_10:
 271                         if (desc[target_id] < 0)
 272                                 break;
 273                         simscsi_readwrite10(sc, SSC_WRITE);
 274                         break;
 275
 276                       case READ_CAPACITY:
 277                         if (desc[target_id] < 0 || scsi_bufflen(sc) < 8) {
 278                                 break;
 279                         }
 280                         buf = localbuf;
 281                         disk_size = simscsi_get_disk_size(desc[target_id]);
 282
 283                         buf[0] = (disk_size >> 24) & 0xff;
 284                         buf[1] = (disk_size >> 16) & 0xff;
 285                         buf[2] = (disk_size >>  8) & 0xff;
 286                         buf[3] = (disk_size >>  0) & 0xff;
 287                         /* set block size of 512 bytes: */
 288                         buf[4] = 0;
 289                         buf[5] = 0;
 290                         buf[6] = 2;
 291                         buf[7] = 0;
 292                         scsi_sg_copy_from_buffer(sc, buf, 8);
 293                         sc->result = GOOD;
 294                         break;
 295
 296                       case MODE_SENSE:
 297                       case MODE_SENSE_10:
 298                         /* sd.c uses this to determine whether disk does write-caching. */
 299                         scsi_sg_copy_from_buffer(sc, (char *)empty_zero_page,
 300                                                  PAGE_SIZE);
 301                         sc->result = GOOD;
 302                         break;
 303
 304                       case START_STOP:
 305                         printk(KERN_ERR "START_STOP\n");
 306                         break;
 307
 308                       default:
 309                         panic("simscsi: unknown SCSI command %u\n", sc->cmnd[0]);
 310                 }
 311         }
 312         if (sc->result == DID_BAD_TARGET) {
 313                 sc->result |= DRIVER_SENSE << 24;
 314                 sc->sense_buffer[0] = 0x70;
 315                 sc->sense_buffer[2] = 0x00;
 316         }
 317         if (atomic_read(&num_reqs) >= SIMSCSI_REQ_QUEUE_LEN) {
 318                 panic("Attempt to queue command while command is pending!!");
 319         }
 320         atomic_inc(&num_reqs);
 321         queue[wr].sc = sc;
 322         wr = (wr + 1) % SIMSCSI_REQ_QUEUE_LEN;
 323
 324         tasklet_schedule(&simscsi_tasklet);
 325         return 0;
 326 }
 327
 328 static int
 329 simscsi_host_reset (struct scsi_cmnd *sc)
 330 {
 331         printk(KERN_ERR "simscsi_host_reset: not implemented\n");
 332         return 0;
 333 }
 334
 335 static struct scsi_host_template driver_template = {
 336         .name                   = "simulated SCSI host adapter",
 337         .proc_name              = "simscsi",
 338         .queuecommand           = simscsi_queuecommand,
 339         .eh_host_reset_handler  = simscsi_host_reset,
 340         .bios_param             = simscsi_biosparam,
 341         .can_queue              = SIMSCSI_REQ_QUEUE_LEN,
 342         .this_id                = -1,
 343         .sg_tablesize           = SG_ALL,
 344         .max_sectors            = 1024,
 345         .cmd_per_lun            = SIMSCSI_REQ_QUEUE_LEN,
 346         .use_clustering         = DISABLE_CLUSTERING,
 347 };
 348
 349 static int __init
 350 simscsi_init(void)
 351 {
 352         int error;
 353
 354         host = scsi_host_alloc(&driver_template, 0);
 355         if (!host)
 356                 return -ENOMEM;
 357
 358         error = scsi_add_host(host, NULL);
 359         if (error)
 360                 goto free_host;
 361         scsi_scan_host(host);
 362         return 0;
 363
 364  free_host:
 365         scsi_host_put(host);
 366         return error;
 367 }
 368
 369 static void __exit
 370 simscsi_exit(void)
 371 {
 372         scsi_remove_host(host);
 373         scsi_host_put(host);
 374 }
 375
 376 module_init(simscsi_init);
 377 module_exit(simscsi_exit);