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         /* 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         } else
  92                 simscsi_root = s;
  93         return 1;
  94 }
  95
  96 __setup("simscsi=", simscsi_setup);
  97
  98 static void
  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
 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
 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
 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
 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
 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
 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
 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
 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 device_initcall(simscsi_init);