arch/ia64/hp/sim/simscsi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Simulated SCSI driver.
   4  *
   5  * Copyright (C) 1999, 2001-2003 Hewlett-Packard Co
   6  *      David Mosberger-Tang <davidm@hpl.hp.com>
   7  *      Stephane Eranian <eranian@hpl.hp.com>
   8  *
   9  * 02/01/15 David Mosberger     Updated for v2.5.1
  10  * 99/12/18 David Mosberger     Added support for READ10/WRITE10 needed by linux v2.3.33
  11  */
  12 #include <linux/blkdev.h>
  13 #include <linux/init.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/kernel.h>
  16 #include <linux/timer.h>
  17 #include <asm/irq.h>
  18 #include "hpsim_ssc.h"
  19
  20 #include <scsi/scsi.h>
  21 #include <scsi/scsi_cmnd.h>
  22 #include <scsi/scsi_device.h>
  23 #include <scsi/scsi_host.h>
  24
  25 #define DEBUG_SIMSCSI   0
  26
  27 #define SIMSCSI_REQ_QUEUE_LEN   64
  28 #define DEFAULT_SIMSCSI_ROOT    "/var/ski-disks/sd"
  29
  30 /* Simulator system calls: */
  31
  32 #define SSC_OPEN                        50
  33 #define SSC_CLOSE                       51
  34 #define SSC_READ                        52
  35 #define SSC_WRITE                       53
  36 #define SSC_GET_COMPLETION              54
  37 #define SSC_WAIT_COMPLETION             55
  38
  39 #define SSC_WRITE_ACCESS                2
  40 #define SSC_READ_ACCESS                 1
  41
  42 #if DEBUG_SIMSCSI
  43   int simscsi_debug;
  44 # define DBG    simscsi_debug
  45 #else
  46 # define DBG    0
  47 #endif
  48
  49 static struct Scsi_Host *host;
  50
  51 static void simscsi_interrupt (unsigned long val);
  52 static DECLARE_TASKLET(simscsi_tasklet, simscsi_interrupt, 0);
  53
  54 struct disk_req {
  55         unsigned long addr;
  56         unsigned len;
  57 };
  58
  59 struct disk_stat {
  60         int fd;
  61         unsigned count;
  62 };
  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         } else
  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(sg_virt(sl));
 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 int
 206 simscsi_queuecommand_lck (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
 207 {
 208         unsigned int target_id = sc->device->id;
 209         char fname[MAX_ROOT_LEN+16];
 210         size_t disk_size;
 211         char *buf;
 212         char localbuf[36];
 213 #if DEBUG_SIMSCSI
 214         register long sp asm ("sp");
 215
 216         if (DBG)
 217                 printk("simscsi_queuecommand: target=%d,cmnd=%u,sc=%lu,sp=%lx,done=%p\n",
 218                        target_id, sc->cmnd[0], sc->serial_number, sp, done);
 219 #endif
 220
 221         sc->result = DID_BAD_TARGET << 16;
 222         sc->scsi_done = done;
 223         if (target_id <= 15 && sc->device->lun == 0) {
 224                 switch (sc->cmnd[0]) {
 225                       case INQUIRY:
 226                         if (scsi_bufflen(sc) < 35) {
 227                                 break;
 228                         }
 229                         sprintf (fname, "%s%c", simscsi_root, 'a' + target_id);
 230                         desc[target_id] = ia64_ssc(__pa(fname), SSC_READ_ACCESS|SSC_WRITE_ACCESS,
 231                                                    0, 0, SSC_OPEN);
 232                         if (desc[target_id] < 0) {
 233                                 /* disk doesn't exist... */
 234                                 break;
 235                         }
 236                         buf = localbuf;
 237                         buf[0] = 0;     /* magnetic disk */
 238                         buf[1] = 0;     /* not a removable medium */
 239                         buf[2] = 2;     /* SCSI-2 compliant device */
 240                         buf[3] = 2;     /* SCSI-2 response data format */
 241                         buf[4] = 31;    /* additional length (bytes) */
 242                         buf[5] = 0;     /* reserved */
 243                         buf[6] = 0;     /* reserved */
 244                         buf[7] = 0;     /* various flags */
 245                         memcpy(buf + 8, "HP      SIMULATED DISK  0.00",  28);
 246                         scsi_sg_copy_from_buffer(sc, buf, 36);
 247                         sc->result = GOOD;
 248                         break;
 249
 250                       case TEST_UNIT_READY:
 251                         sc->result = GOOD;
 252                         break;
 253
 254                       case READ_6:
 255                         if (desc[target_id] < 0 )
 256                                 break;
 257                         simscsi_readwrite6(sc, SSC_READ);
 258                         break;
 259
 260                       case READ_10:
 261                         if (desc[target_id] < 0 )
 262                                 break;
 263                         simscsi_readwrite10(sc, SSC_READ);
 264                         break;
 265
 266                       case WRITE_6:
 267                         if (desc[target_id] < 0)
 268                                 break;
 269                         simscsi_readwrite6(sc, SSC_WRITE);
 270                         break;
 271
 272                       case WRITE_10:
 273                         if (desc[target_id] < 0)
 274                                 break;
 275                         simscsi_readwrite10(sc, SSC_WRITE);
 276                         break;
 277
 278                       case READ_CAPACITY:
 279                         if (desc[target_id] < 0 || scsi_bufflen(sc) < 8) {
 280                                 break;
 281                         }
 282                         buf = localbuf;
 283                         disk_size = simscsi_get_disk_size(desc[target_id]);
 284
 285                         buf[0] = (disk_size >> 24) & 0xff;
 286                         buf[1] = (disk_size >> 16) & 0xff;
 287                         buf[2] = (disk_size >>  8) & 0xff;
 288                         buf[3] = (disk_size >>  0) & 0xff;
 289                         /* set block size of 512 bytes: */
 290                         buf[4] = 0;
 291                         buf[5] = 0;
 292                         buf[6] = 2;
 293                         buf[7] = 0;
 294                         scsi_sg_copy_from_buffer(sc, buf, 8);
 295                         sc->result = GOOD;
 296                         break;
 297
 298                       case MODE_SENSE:
 299                       case MODE_SENSE_10:
 300                         /* sd.c uses this to determine whether disk does write-caching. */
 301                         scsi_sg_copy_from_buffer(sc, (char *)empty_zero_page,
 302                                                  PAGE_SIZE);
 303                         sc->result = GOOD;
 304                         break;
 305
 306                       case START_STOP:
 307                         printk(KERN_ERR "START_STOP\n");
 308                         break;
 309
 310                       default:
 311                         panic("simscsi: unknown SCSI command %u\n", sc->cmnd[0]);
 312                 }
 313         }
 314         if (sc->result == DID_BAD_TARGET) {
 315                 sc->result |= DRIVER_SENSE << 24;
 316                 sc->sense_buffer[0] = 0x70;
 317                 sc->sense_buffer[2] = 0x00;
 318         }
 319         if (atomic_read(&num_reqs) >= SIMSCSI_REQ_QUEUE_LEN) {
 320                 panic("Attempt to queue command while command is pending!!");
 321         }
 322         atomic_inc(&num_reqs);
 323         queue[wr].sc = sc;
 324         wr = (wr + 1) % SIMSCSI_REQ_QUEUE_LEN;
 325
 326         tasklet_schedule(&simscsi_tasklet);
 327         return 0;
 328 }
 329
 330 static DEF_SCSI_QCMD(simscsi_queuecommand)
 331
 332 static int
 333 simscsi_host_reset (struct scsi_cmnd *sc)
 334 {
 335         printk(KERN_ERR "simscsi_host_reset: not implemented\n");
 336         return 0;
 337 }
 338
 339 static struct scsi_host_template driver_template = {
 340         .name                   = "simulated SCSI host adapter",
 341         .proc_name              = "simscsi",
 342         .queuecommand           = simscsi_queuecommand,
 343         .eh_host_reset_handler  = simscsi_host_reset,
 344         .bios_param             = simscsi_biosparam,
 345         .can_queue              = SIMSCSI_REQ_QUEUE_LEN,
 346         .this_id                = -1,
 347         .sg_tablesize           = SG_ALL,
 348         .max_sectors            = 1024,
 349         .cmd_per_lun            = SIMSCSI_REQ_QUEUE_LEN,
 350         .use_clustering         = DISABLE_CLUSTERING,
 351 };
 352
 353 static int __init
 354 simscsi_init(void)
 355 {
 356         int error;
 357
 358         host = scsi_host_alloc(&driver_template, 0);
 359         if (!host)
 360                 return -ENOMEM;
 361
 362         error = scsi_add_host(host, NULL);
 363         if (error)
 364                 goto free_host;
 365         scsi_scan_host(host);
 366         return 0;
 367
 368  free_host:
 369         scsi_host_put(host);
 370         return error;
 371 }
 372 device_initcall(simscsi_init);