drivers/scsi/ppa.c

   1 /* ppa.c   --  low level driver for the IOMEGA PPA3
   2  * parallel port SCSI host adapter.
   3  *
   4  * (The PPA3 is the embedded controller in the ZIP drive.)
   5  *
   6  * (c) 1995,1996 Grant R. Guenther, grant@torque.net,
   7  * under the terms of the GNU General Public License.
   8  *
   9  * Current Maintainer: David Campbell (Perth, Western Australia, GMT+0800)
  10  *                     campbell@torque.net
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/blkdev.h>
  18 #include <linux/parport.h>
  19 #include <linux/workqueue.h>
  20 #include <linux/delay.h>
  21 #include <linux/jiffies.h>
  22 #include <asm/io.h>
  23
  24 #include <scsi/scsi.h>
  25 #include <scsi/scsi_cmnd.h>
  26 #include <scsi/scsi_device.h>
  27 #include <scsi/scsi_host.h>
  28
  29
  30 static void ppa_reset_pulse(unsigned int base);
  31
  32 typedef struct {
  33         struct pardevice *dev;  /* Parport device entry         */
  34         int base;               /* Actual port address          */
  35         int mode;               /* Transfer mode                */
  36         struct scsi_cmnd *cur_cmd;      /* Current queued command       */
  37         struct work_struct ppa_tq;      /* Polling interrupt stuff       */
  38         unsigned long jstart;   /* Jiffies at start             */
  39         unsigned long recon_tmo;        /* How many usecs to wait for reconnection (6th bit) */
  40         unsigned int failed:1;  /* Failure flag                 */
  41         unsigned wanted:1;      /* Parport sharing busy flag    */
  42         wait_queue_head_t *waiting;
  43         struct Scsi_Host *host;
  44         struct list_head list;
  45 } ppa_struct;
  46
  47 #include  "ppa.h"
  48
  49 static inline ppa_struct *ppa_dev(struct Scsi_Host *host)
  50 {
  51         return *(ppa_struct **)&host->hostdata;
  52 }
  53
  54 static DEFINE_SPINLOCK(arbitration_lock);
  55
  56 static void got_it(ppa_struct *dev)
  57 {
  58         dev->base = dev->dev->port->base;
  59         if (dev->cur_cmd)
  60                 dev->cur_cmd->SCp.phase = 1;
  61         else
  62                 wake_up(dev->waiting);
  63 }
  64
  65 static void ppa_wakeup(void *ref)
  66 {
  67         ppa_struct *dev = (ppa_struct *) ref;
  68         unsigned long flags;
  69
  70         spin_lock_irqsave(&arbitration_lock, flags);
  71         if (dev->wanted) {
  72                 parport_claim(dev->dev);
  73                 got_it(dev);
  74                 dev->wanted = 0;
  75         }
  76         spin_unlock_irqrestore(&arbitration_lock, flags);
  77         return;
  78 }
  79
  80 static int ppa_pb_claim(ppa_struct *dev)
  81 {
  82         unsigned long flags;
  83         int res = 1;
  84         spin_lock_irqsave(&arbitration_lock, flags);
  85         if (parport_claim(dev->dev) == 0) {
  86                 got_it(dev);
  87                 res = 0;
  88         }
  89         dev->wanted = res;
  90         spin_unlock_irqrestore(&arbitration_lock, flags);
  91         return res;
  92 }
  93
  94 static void ppa_pb_dismiss(ppa_struct *dev)
  95 {
  96         unsigned long flags;
  97         int wanted;
  98         spin_lock_irqsave(&arbitration_lock, flags);
  99         wanted = dev->wanted;
 100         dev->wanted = 0;
 101         spin_unlock_irqrestore(&arbitration_lock, flags);
 102         if (!wanted)
 103                 parport_release(dev->dev);
 104 }
 105
 106 static inline void ppa_pb_release(ppa_struct *dev)
 107 {
 108         parport_release(dev->dev);
 109 }
 110
 111 /*
 112  * Start of Chipset kludges
 113  */
 114
 115 /* This is to give the ppa driver a way to modify the timings (and other
 116  * parameters) by writing to the /proc/scsi/ppa/0 file.
 117  * Very simple method really... (To simple, no error checking :( )
 118  * Reason: Kernel hackers HATE having to unload and reload modules for
 119  * testing...
 120  * Also gives a method to use a script to obtain optimum timings (TODO)
 121  */
 122
 123 static inline int ppa_proc_write(ppa_struct *dev, char *buffer, int length)
 124 {
 125         unsigned long x;
 126
 127         if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
 128                 x = simple_strtoul(buffer + 5, NULL, 0);
 129                 dev->mode = x;
 130                 return length;
 131         }
 132         if ((length > 10) && (strncmp(buffer, "recon_tmo=", 10) == 0)) {
 133                 x = simple_strtoul(buffer + 10, NULL, 0);
 134                 dev->recon_tmo = x;
 135                 printk("ppa: recon_tmo set to %ld\n", x);
 136                 return length;
 137         }
 138         printk("ppa /proc: invalid variable\n");
 139         return (-EINVAL);
 140 }
 141
 142 static int ppa_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset, int length, int inout)
 143 {
 144         int len = 0;
 145         ppa_struct *dev = ppa_dev(host);
 146
 147         if (inout)
 148                 return ppa_proc_write(dev, buffer, length);
 149
 150         len += sprintf(buffer + len, "Version : %s\n", PPA_VERSION);
 151         len +=
 152             sprintf(buffer + len, "Parport : %s\n",
 153                     dev->dev->port->name);
 154         len +=
 155             sprintf(buffer + len, "Mode    : %s\n",
 156                     PPA_MODE_STRING[dev->mode]);
 157 #if PPA_DEBUG > 0
 158         len +=
 159             sprintf(buffer + len, "recon_tmo : %lu\n", dev->recon_tmo);
 160 #endif
 161
 162         /* Request for beyond end of buffer */
 163         if (offset > length)
 164                 return 0;
 165
 166         *start = buffer + offset;
 167         len -= offset;
 168         if (len > length)
 169                 len = length;
 170         return len;
 171 }
 172
 173 static int device_check(ppa_struct *dev);
 174
 175 #if PPA_DEBUG > 0
 176 #define ppa_fail(x,y) printk("ppa: ppa_fail(%i) from %s at line %d\n",\
 177            y, __FUNCTION__, __LINE__); ppa_fail_func(x,y);
 178 static inline void ppa_fail_func(ppa_struct *dev, int error_code)
 179 #else
 180 static inline void ppa_fail(ppa_struct *dev, int error_code)
 181 #endif
 182 {
 183         /* If we fail a device then we trash status / message bytes */
 184         if (dev->cur_cmd) {
 185                 dev->cur_cmd->result = error_code << 16;
 186                 dev->failed = 1;
 187         }
 188 }
 189
 190 /*
 191  * Wait for the high bit to be set.
 192  *
 193  * In principle, this could be tied to an interrupt, but the adapter
 194  * doesn't appear to be designed to support interrupts.  We spin on
 195  * the 0x80 ready bit.
 196  */
 197 static unsigned char ppa_wait(ppa_struct *dev)
 198 {
 199         int k;
 200         unsigned short ppb = dev->base;
 201         unsigned char r;
 202
 203         k = PPA_SPIN_TMO;
 204         /* Wait for bit 6 and 7 - PJC */
 205         for (r = r_str(ppb); ((r & 0xc0) != 0xc0) && (k); k--) {
 206                 udelay(1);
 207                 r = r_str(ppb);
 208         }
 209
 210         /*
 211          * return some status information.
 212          * Semantics: 0xc0 = ZIP wants more data
 213          *            0xd0 = ZIP wants to send more data
 214          *            0xe0 = ZIP is expecting SCSI command data
 215          *            0xf0 = end of transfer, ZIP is sending status
 216          */
 217         if (k)
 218                 return (r & 0xf0);
 219
 220         /* Counter expired - Time out occurred */
 221         ppa_fail(dev, DID_TIME_OUT);
 222         printk("ppa timeout in ppa_wait\n");
 223         return 0;               /* command timed out */
 224 }
 225
 226 /*
 227  * Clear EPP Timeout Bit
 228  */
 229 static inline void epp_reset(unsigned short ppb)
 230 {
 231         int i;
 232
 233         i = r_str(ppb);
 234         w_str(ppb, i);
 235         w_str(ppb, i & 0xfe);
 236 }
 237
 238 /*
 239  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
 240  */
 241 static inline void ecp_sync(ppa_struct *dev)
 242 {
 243         int i, ppb_hi = dev->dev->port->base_hi;
 244
 245         if (ppb_hi == 0)
 246                 return;
 247
 248         if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {   /* mode 011 == ECP fifo mode */
 249                 for (i = 0; i < 100; i++) {
 250                         if (r_ecr(ppb_hi) & 0x01)
 251                                 return;
 252                         udelay(5);
 253                 }
 254                 printk("ppa: ECP sync failed as data still present in FIFO.\n");
 255         }
 256 }
 257
 258 static int ppa_byte_out(unsigned short base, const char *buffer, int len)
 259 {
 260         int i;
 261
 262         for (i = len; i; i--) {
 263                 w_dtr(base, *buffer++);
 264                 w_ctr(base, 0xe);
 265                 w_ctr(base, 0xc);
 266         }
 267         return 1;               /* All went well - we hope! */
 268 }
 269
 270 static int ppa_byte_in(unsigned short base, char *buffer, int len)
 271 {
 272         int i;
 273
 274         for (i = len; i; i--) {
 275                 *buffer++ = r_dtr(base);
 276                 w_ctr(base, 0x27);
 277                 w_ctr(base, 0x25);
 278         }
 279         return 1;               /* All went well - we hope! */
 280 }
 281
 282 static int ppa_nibble_in(unsigned short base, char *buffer, int len)
 283 {
 284         for (; len; len--) {
 285                 unsigned char h;
 286
 287                 w_ctr(base, 0x4);
 288                 h = r_str(base) & 0xf0;
 289                 w_ctr(base, 0x6);
 290                 *buffer++ = h | ((r_str(base) & 0xf0) >> 4);
 291         }
 292         return 1;               /* All went well - we hope! */
 293 }
 294
 295 static int ppa_out(ppa_struct *dev, char *buffer, int len)
 296 {
 297         int r;
 298         unsigned short ppb = dev->base;
 299
 300         r = ppa_wait(dev);
 301
 302         if ((r & 0x50) != 0x40) {
 303                 ppa_fail(dev, DID_ERROR);
 304                 return 0;
 305         }
 306         switch (dev->mode) {
 307         case PPA_NIBBLE:
 308         case PPA_PS2:
 309                 /* 8 bit output, with a loop */
 310                 r = ppa_byte_out(ppb, buffer, len);
 311                 break;
 312
 313         case PPA_EPP_32:
 314         case PPA_EPP_16:
 315         case PPA_EPP_8:
 316                 epp_reset(ppb);
 317                 w_ctr(ppb, 0x4);
 318 #ifdef CONFIG_SCSI_IZIP_EPP16
 319                 if (!(((long) buffer | len) & 0x01))
 320                         outsw(ppb + 4, buffer, len >> 1);
 321 #else
 322                 if (!(((long) buffer | len) & 0x03))
 323                         outsl(ppb + 4, buffer, len >> 2);
 324 #endif
 325                 else
 326                         outsb(ppb + 4, buffer, len);
 327                 w_ctr(ppb, 0xc);
 328                 r = !(r_str(ppb) & 0x01);
 329                 w_ctr(ppb, 0xc);
 330                 ecp_sync(dev);
 331                 break;
 332
 333         default:
 334                 printk("PPA: bug in ppa_out()\n");
 335                 r = 0;
 336         }
 337         return r;
 338 }
 339
 340 static int ppa_in(ppa_struct *dev, char *buffer, int len)
 341 {
 342         int r;
 343         unsigned short ppb = dev->base;
 344
 345         r = ppa_wait(dev);
 346
 347         if ((r & 0x50) != 0x50) {
 348                 ppa_fail(dev, DID_ERROR);
 349                 return 0;
 350         }
 351         switch (dev->mode) {
 352         case PPA_NIBBLE:
 353                 /* 4 bit input, with a loop */
 354                 r = ppa_nibble_in(ppb, buffer, len);
 355                 w_ctr(ppb, 0xc);
 356                 break;
 357
 358         case PPA_PS2:
 359                 /* 8 bit input, with a loop */
 360                 w_ctr(ppb, 0x25);
 361                 r = ppa_byte_in(ppb, buffer, len);
 362                 w_ctr(ppb, 0x4);
 363                 w_ctr(ppb, 0xc);
 364                 break;
 365
 366         case PPA_EPP_32:
 367         case PPA_EPP_16:
 368         case PPA_EPP_8:
 369                 epp_reset(ppb);
 370                 w_ctr(ppb, 0x24);
 371 #ifdef CONFIG_SCSI_IZIP_EPP16
 372                 if (!(((long) buffer | len) & 0x01))
 373                         insw(ppb + 4, buffer, len >> 1);
 374 #else
 375                 if (!(((long) buffer | len) & 0x03))
 376                         insl(ppb + 4, buffer, len >> 2);
 377 #endif
 378                 else
 379                         insb(ppb + 4, buffer, len);
 380                 w_ctr(ppb, 0x2c);
 381                 r = !(r_str(ppb) & 0x01);
 382                 w_ctr(ppb, 0x2c);
 383                 ecp_sync(dev);
 384                 break;
 385
 386         default:
 387                 printk("PPA: bug in ppa_ins()\n");
 388                 r = 0;
 389                 break;
 390         }
 391         return r;
 392 }
 393
 394 /* end of ppa_io.h */
 395 static inline void ppa_d_pulse(unsigned short ppb, unsigned char b)
 396 {
 397         w_dtr(ppb, b);
 398         w_ctr(ppb, 0xc);
 399         w_ctr(ppb, 0xe);
 400         w_ctr(ppb, 0xc);
 401         w_ctr(ppb, 0x4);
 402         w_ctr(ppb, 0xc);
 403 }
 404
 405 static void ppa_disconnect(ppa_struct *dev)
 406 {
 407         unsigned short ppb = dev->base;
 408
 409         ppa_d_pulse(ppb, 0);
 410         ppa_d_pulse(ppb, 0x3c);
 411         ppa_d_pulse(ppb, 0x20);
 412         ppa_d_pulse(ppb, 0xf);
 413 }
 414
 415 static inline void ppa_c_pulse(unsigned short ppb, unsigned char b)
 416 {
 417         w_dtr(ppb, b);
 418         w_ctr(ppb, 0x4);
 419         w_ctr(ppb, 0x6);
 420         w_ctr(ppb, 0x4);
 421         w_ctr(ppb, 0xc);
 422 }
 423
 424 static inline void ppa_connect(ppa_struct *dev, int flag)
 425 {
 426         unsigned short ppb = dev->base;
 427
 428         ppa_c_pulse(ppb, 0);
 429         ppa_c_pulse(ppb, 0x3c);
 430         ppa_c_pulse(ppb, 0x20);
 431         if ((flag == CONNECT_EPP_MAYBE) && IN_EPP_MODE(dev->mode))
 432                 ppa_c_pulse(ppb, 0xcf);
 433         else
 434                 ppa_c_pulse(ppb, 0x8f);
 435 }
 436
 437 static int ppa_select(ppa_struct *dev, int target)
 438 {
 439         int k;
 440         unsigned short ppb = dev->base;
 441
 442         /*
 443          * Bit 6 (0x40) is the device selected bit.
 444          * First we must wait till the current device goes off line...
 445          */
 446         k = PPA_SELECT_TMO;
 447         do {
 448                 k--;
 449                 udelay(1);
 450         } while ((r_str(ppb) & 0x40) && (k));
 451         if (!k)
 452                 return 0;
 453
 454         w_dtr(ppb, (1 << target));
 455         w_ctr(ppb, 0xe);
 456         w_ctr(ppb, 0xc);
 457         w_dtr(ppb, 0x80);       /* This is NOT the initator */
 458         w_ctr(ppb, 0x8);
 459
 460         k = PPA_SELECT_TMO;
 461         do {
 462                 k--;
 463                 udelay(1);
 464         }
 465         while (!(r_str(ppb) & 0x40) && (k));
 466         if (!k)
 467                 return 0;
 468
 469         return 1;
 470 }
 471
 472 /*
 473  * This is based on a trace of what the Iomega DOS 'guest' driver does.
 474  * I've tried several different kinds of parallel ports with guest and
 475  * coded this to react in the same ways that it does.
 476  *
 477  * The return value from this function is just a hint about where the
 478  * handshaking failed.
 479  *
 480  */
 481 static int ppa_init(ppa_struct *dev)
 482 {
 483         int retv;
 484         unsigned short ppb = dev->base;
 485
 486         ppa_disconnect(dev);
 487         ppa_connect(dev, CONNECT_NORMAL);
 488
 489         retv = 2;               /* Failed */
 490
 491         w_ctr(ppb, 0xe);
 492         if ((r_str(ppb) & 0x08) == 0x08)
 493                 retv--;
 494
 495         w_ctr(ppb, 0xc);
 496         if ((r_str(ppb) & 0x08) == 0x00)
 497                 retv--;
 498
 499         if (!retv)
 500                 ppa_reset_pulse(ppb);
 501         udelay(1000);           /* Allow devices to settle down */
 502         ppa_disconnect(dev);
 503         udelay(1000);           /* Another delay to allow devices to settle */
 504
 505         if (retv)
 506                 return -EIO;
 507
 508         return device_check(dev);
 509 }
 510
 511 static inline int ppa_send_command(struct scsi_cmnd *cmd)
 512 {
 513         ppa_struct *dev = ppa_dev(cmd->device->host);
 514         int k;
 515
 516         w_ctr(dev->base, 0x0c);
 517
 518         for (k = 0; k < cmd->cmd_len; k++)
 519                 if (!ppa_out(dev, &cmd->cmnd[k], 1))
 520                         return 0;
 521         return 1;
 522 }
 523
 524 /*
 525  * The bulk flag enables some optimisations in the data transfer loops,
 526  * it should be true for any command that transfers data in integral
 527  * numbers of sectors.
 528  *
 529  * The driver appears to remain stable if we speed up the parallel port
 530  * i/o in this function, but not elsewhere.
 531  */
 532 static int ppa_completion(struct scsi_cmnd *cmd)
 533 {
 534         /* Return codes:
 535          * -1     Error
 536          *  0     Told to schedule
 537          *  1     Finished data transfer
 538          */
 539         ppa_struct *dev = ppa_dev(cmd->device->host);
 540         unsigned short ppb = dev->base;
 541         unsigned long start_jiffies = jiffies;
 542
 543         unsigned char r, v;
 544         int fast, bulk, status;
 545
 546         v = cmd->cmnd[0];
 547         bulk = ((v == READ_6) ||
 548                 (v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
 549
 550         /*
 551          * We only get here if the drive is ready to comunicate,
 552          * hence no need for a full ppa_wait.
 553          */
 554         r = (r_str(ppb) & 0xf0);
 555
 556         while (r != (unsigned char) 0xf0) {
 557                 /*
 558                  * If we have been running for more than a full timer tick
 559                  * then take a rest.
 560                  */
 561                 if (time_after(jiffies, start_jiffies + 1))
 562                         return 0;
 563
 564                 if ((cmd->SCp.this_residual <= 0)) {
 565                         ppa_fail(dev, DID_ERROR);
 566                         return -1;      /* ERROR_RETURN */
 567                 }
 568
 569                 /* On some hardware we have SCSI disconnected (6th bit low)
 570                  * for about 100usecs. It is too expensive to wait a
 571                  * tick on every loop so we busy wait for no more than
 572                  * 500usecs to give the drive a chance first. We do not
 573                  * change things for "normal" hardware since generally
 574                  * the 6th bit is always high.
 575                  * This makes the CPU load higher on some hardware
 576                  * but otherwise we can not get more than 50K/secs
 577                  * on this problem hardware.
 578                  */
 579                 if ((r & 0xc0) != 0xc0) {
 580                         /* Wait for reconnection should be no more than
 581                          * jiffy/2 = 5ms = 5000 loops
 582                          */
 583                         unsigned long k = dev->recon_tmo;
 584                         for (; k && ((r = (r_str(ppb) & 0xf0)) & 0xc0) != 0xc0;
 585                              k--)
 586                                 udelay(1);
 587
 588                         if (!k)
 589                                 return 0;
 590                 }
 591
 592                 /* determine if we should use burst I/O */
 593                 fast = (bulk && (cmd->SCp.this_residual >= PPA_BURST_SIZE))
 594                     ? PPA_BURST_SIZE : 1;
 595
 596                 if (r == (unsigned char) 0xc0)
 597                         status = ppa_out(dev, cmd->SCp.ptr, fast);
 598                 else
 599                         status = ppa_in(dev, cmd->SCp.ptr, fast);
 600
 601                 cmd->SCp.ptr += fast;
 602                 cmd->SCp.this_residual -= fast;
 603
 604                 if (!status) {
 605                         ppa_fail(dev, DID_BUS_BUSY);
 606                         return -1;      /* ERROR_RETURN */
 607                 }
 608                 if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
 609                         /* if scatter/gather, advance to the next segment */
 610                         if (cmd->SCp.buffers_residual--) {
 611                                 cmd->SCp.buffer++;
 612                                 cmd->SCp.this_residual =
 613                                     cmd->SCp.buffer->length;
 614                                 cmd->SCp.ptr =
 615                                     page_address(cmd->SCp.buffer->page) +
 616                                     cmd->SCp.buffer->offset;
 617                         }
 618                 }
 619                 /* Now check to see if the drive is ready to comunicate */
 620                 r = (r_str(ppb) & 0xf0);
 621                 /* If not, drop back down to the scheduler and wait a timer tick */
 622                 if (!(r & 0x80))
 623                         return 0;
 624         }
 625         return 1;               /* FINISH_RETURN */
 626 }
 627
 628 /*
 629  * Since the PPA itself doesn't generate interrupts, we use
 630  * the scheduler's task queue to generate a stream of call-backs and
 631  * complete the request when the drive is ready.
 632  */
 633 static void ppa_interrupt(void *data)
 634 {
 635         ppa_struct *dev = (ppa_struct *) data;
 636         struct scsi_cmnd *cmd = dev->cur_cmd;
 637
 638         if (!cmd) {
 639                 printk("PPA: bug in ppa_interrupt\n");
 640                 return;
 641         }
 642         if (ppa_engine(dev, cmd)) {
 643                 dev->ppa_tq.data = (void *) dev;
 644                 schedule_delayed_work(&dev->ppa_tq, 1);
 645                 return;
 646         }
 647         /* Command must of completed hence it is safe to let go... */
 648 #if PPA_DEBUG > 0
 649         switch ((cmd->result >> 16) & 0xff) {
 650         case DID_OK:
 651                 break;
 652         case DID_NO_CONNECT:
 653                 printk("ppa: no device at SCSI ID %i\n", cmd->device->target);
 654                 break;
 655         case DID_BUS_BUSY:
 656                 printk("ppa: BUS BUSY - EPP timeout detected\n");
 657                 break;
 658         case DID_TIME_OUT:
 659                 printk("ppa: unknown timeout\n");
 660                 break;
 661         case DID_ABORT:
 662                 printk("ppa: told to abort\n");
 663                 break;
 664         case DID_PARITY:
 665                 printk("ppa: parity error (???)\n");
 666                 break;
 667         case DID_ERROR:
 668                 printk("ppa: internal driver error\n");
 669                 break;
 670         case DID_RESET:
 671                 printk("ppa: told to reset device\n");
 672                 break;
 673         case DID_BAD_INTR:
 674                 printk("ppa: bad interrupt (???)\n");
 675                 break;
 676         default:
 677                 printk("ppa: bad return code (%02x)\n",
 678                        (cmd->result >> 16) & 0xff);
 679         }
 680 #endif
 681
 682         if (cmd->SCp.phase > 1)
 683                 ppa_disconnect(dev);
 684
 685         ppa_pb_dismiss(dev);
 686
 687         dev->cur_cmd = NULL;
 688
 689         cmd->scsi_done(cmd);
 690 }
 691
 692 static int ppa_engine(ppa_struct *dev, struct scsi_cmnd *cmd)
 693 {
 694         unsigned short ppb = dev->base;
 695         unsigned char l = 0, h = 0;
 696         int retv;
 697
 698         /* First check for any errors that may of occurred
 699          * Here we check for internal errors
 700          */
 701         if (dev->failed)
 702                 return 0;
 703
 704         switch (cmd->SCp.phase) {
 705         case 0:         /* Phase 0 - Waiting for parport */
 706                 if (time_after(jiffies, dev->jstart + HZ)) {
 707                         /*
 708                          * We waited more than a second
 709                          * for parport to call us
 710                          */
 711                         ppa_fail(dev, DID_BUS_BUSY);
 712                         return 0;
 713                 }
 714                 return 1;       /* wait until ppa_wakeup claims parport */
 715         case 1:         /* Phase 1 - Connected */
 716                 {               /* Perform a sanity check for cable unplugged */
 717                         int retv = 2;   /* Failed */
 718
 719                         ppa_connect(dev, CONNECT_EPP_MAYBE);
 720
 721                         w_ctr(ppb, 0xe);
 722                         if ((r_str(ppb) & 0x08) == 0x08)
 723                                 retv--;
 724
 725                         w_ctr(ppb, 0xc);
 726                         if ((r_str(ppb) & 0x08) == 0x00)
 727                                 retv--;
 728
 729                         if (retv) {
 730                                 if (time_after(jiffies, dev->jstart + (1 * HZ))) {
 731                                         printk
 732                                             ("ppa: Parallel port cable is unplugged!!\n");
 733                                         ppa_fail(dev, DID_BUS_BUSY);
 734                                         return 0;
 735                                 } else {
 736                                         ppa_disconnect(dev);
 737                                         return 1;       /* Try again in a jiffy */
 738                                 }
 739                         }
 740                         cmd->SCp.phase++;
 741                 }
 742
 743         case 2:         /* Phase 2 - We are now talking to the scsi bus */
 744                 if (!ppa_select(dev, scmd_id(cmd))) {
 745                         ppa_fail(dev, DID_NO_CONNECT);
 746                         return 0;
 747                 }
 748                 cmd->SCp.phase++;
 749
 750         case 3:         /* Phase 3 - Ready to accept a command */
 751                 w_ctr(ppb, 0x0c);
 752                 if (!(r_str(ppb) & 0x80))
 753                         return 1;
 754
 755                 if (!ppa_send_command(cmd))
 756                         return 0;
 757                 cmd->SCp.phase++;
 758
 759         case 4:         /* Phase 4 - Setup scatter/gather buffers */
 760                 if (cmd->use_sg) {
 761                         /* if many buffers are available, start filling the first */
 762                         cmd->SCp.buffer =
 763                             (struct scatterlist *) cmd->request_buffer;
 764                         cmd->SCp.this_residual = cmd->SCp.buffer->length;
 765                         cmd->SCp.ptr =
 766                             page_address(cmd->SCp.buffer->page) +
 767                             cmd->SCp.buffer->offset;
 768                 } else {
 769                         /* else fill the only available buffer */
 770                         cmd->SCp.buffer = NULL;
 771                         cmd->SCp.this_residual = cmd->request_bufflen;
 772                         cmd->SCp.ptr = cmd->request_buffer;
 773                 }
 774                 cmd->SCp.buffers_residual = cmd->use_sg - 1;
 775                 cmd->SCp.phase++;
 776
 777         case 5:         /* Phase 5 - Data transfer stage */
 778                 w_ctr(ppb, 0x0c);
 779                 if (!(r_str(ppb) & 0x80))
 780                         return 1;
 781
 782                 retv = ppa_completion(cmd);
 783                 if (retv == -1)
 784                         return 0;
 785                 if (retv == 0)
 786                         return 1;
 787                 cmd->SCp.phase++;
 788
 789         case 6:         /* Phase 6 - Read status/message */
 790                 cmd->result = DID_OK << 16;
 791                 /* Check for data overrun */
 792                 if (ppa_wait(dev) != (unsigned char) 0xf0) {
 793                         ppa_fail(dev, DID_ERROR);
 794                         return 0;
 795                 }
 796                 if (ppa_in(dev, &l, 1)) {       /* read status byte */
 797                         /* Check for optional message byte */
 798                         if (ppa_wait(dev) == (unsigned char) 0xf0)
 799                                 ppa_in(dev, &h, 1);
 800                         cmd->result =
 801                             (DID_OK << 16) + (h << 8) + (l & STATUS_MASK);
 802                 }
 803                 return 0;       /* Finished */
 804                 break;
 805
 806         default:
 807                 printk("ppa: Invalid scsi phase\n");
 808         }
 809         return 0;
 810 }
 811
 812 static int ppa_queuecommand(struct scsi_cmnd *cmd,
 813                 void (*done) (struct scsi_cmnd *))
 814 {
 815         ppa_struct *dev = ppa_dev(cmd->device->host);
 816
 817         if (dev->cur_cmd) {
 818                 printk("PPA: bug in ppa_queuecommand\n");
 819                 return 0;
 820         }
 821         dev->failed = 0;
 822         dev->jstart = jiffies;
 823         dev->cur_cmd = cmd;
 824         cmd->scsi_done = done;
 825         cmd->result = DID_ERROR << 16;  /* default return code */
 826         cmd->SCp.phase = 0;     /* bus free */
 827
 828         dev->ppa_tq.data = dev;
 829         schedule_work(&dev->ppa_tq);
 830
 831         ppa_pb_claim(dev);
 832
 833         return 0;
 834 }
 835
 836 /*
 837  * Apparently the disk->capacity attribute is off by 1 sector
 838  * for all disk drives.  We add the one here, but it should really
 839  * be done in sd.c.  Even if it gets fixed there, this will still
 840  * work.
 841  */
 842 static int ppa_biosparam(struct scsi_device *sdev, struct block_device *dev,
 843               sector_t capacity, int ip[])
 844 {
 845         ip[0] = 0x40;
 846         ip[1] = 0x20;
 847         ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
 848         if (ip[2] > 1024) {
 849                 ip[0] = 0xff;
 850                 ip[1] = 0x3f;
 851                 ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
 852                 if (ip[2] > 1023)
 853                         ip[2] = 1023;
 854         }
 855         return 0;
 856 }
 857
 858 static int ppa_abort(struct scsi_cmnd *cmd)
 859 {
 860         ppa_struct *dev = ppa_dev(cmd->device->host);
 861         /*
 862          * There is no method for aborting commands since Iomega
 863          * have tied the SCSI_MESSAGE line high in the interface
 864          */
 865
 866         switch (cmd->SCp.phase) {
 867         case 0:         /* Do not have access to parport */
 868         case 1:         /* Have not connected to interface */
 869                 dev->cur_cmd = NULL;    /* Forget the problem */
 870                 return SUCCESS;
 871                 break;
 872         default:                /* SCSI command sent, can not abort */
 873                 return FAILED;
 874                 break;
 875         }
 876 }
 877
 878 static void ppa_reset_pulse(unsigned int base)
 879 {
 880         w_dtr(base, 0x40);
 881         w_ctr(base, 0x8);
 882         udelay(30);
 883         w_ctr(base, 0xc);
 884 }
 885
 886 static int ppa_reset(struct scsi_cmnd *cmd)
 887 {
 888         ppa_struct *dev = ppa_dev(cmd->device->host);
 889
 890         if (cmd->SCp.phase)
 891                 ppa_disconnect(dev);
 892         dev->cur_cmd = NULL;    /* Forget the problem */
 893
 894         ppa_connect(dev, CONNECT_NORMAL);
 895         ppa_reset_pulse(dev->base);
 896         mdelay(1);              /* device settle delay */
 897         ppa_disconnect(dev);
 898         mdelay(1);              /* device settle delay */
 899         return SUCCESS;
 900 }
 901
 902 static int device_check(ppa_struct *dev)
 903 {
 904         /* This routine looks for a device and then attempts to use EPP
 905            to send a command. If all goes as planned then EPP is available. */
 906
 907         static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
 908         int loop, old_mode, status, k, ppb = dev->base;
 909         unsigned char l;
 910
 911         old_mode = dev->mode;
 912         for (loop = 0; loop < 8; loop++) {
 913                 /* Attempt to use EPP for Test Unit Ready */
 914                 if ((ppb & 0x0007) == 0x0000)
 915                         dev->mode = PPA_EPP_32;
 916
 917               second_pass:
 918                 ppa_connect(dev, CONNECT_EPP_MAYBE);
 919                 /* Select SCSI device */
 920                 if (!ppa_select(dev, loop)) {
 921                         ppa_disconnect(dev);
 922                         continue;
 923                 }
 924                 printk("ppa: Found device at ID %i, Attempting to use %s\n",
 925                        loop, PPA_MODE_STRING[dev->mode]);
 926
 927                 /* Send SCSI command */
 928                 status = 1;
 929                 w_ctr(ppb, 0x0c);
 930                 for (l = 0; (l < 6) && (status); l++)
 931                         status = ppa_out(dev, cmd, 1);
 932
 933                 if (!status) {
 934                         ppa_disconnect(dev);
 935                         ppa_connect(dev, CONNECT_EPP_MAYBE);
 936                         w_dtr(ppb, 0x40);
 937                         w_ctr(ppb, 0x08);
 938                         udelay(30);
 939                         w_ctr(ppb, 0x0c);
 940                         udelay(1000);
 941                         ppa_disconnect(dev);
 942                         udelay(1000);
 943                         if (dev->mode == PPA_EPP_32) {
 944                                 dev->mode = old_mode;
 945                                 goto second_pass;
 946                         }
 947                         return -EIO;
 948                 }
 949                 w_ctr(ppb, 0x0c);
 950                 k = 1000000;    /* 1 Second */
 951                 do {
 952                         l = r_str(ppb);
 953                         k--;
 954                         udelay(1);
 955                 } while (!(l & 0x80) && (k));
 956
 957                 l &= 0xf0;
 958
 959                 if (l != 0xf0) {
 960                         ppa_disconnect(dev);
 961                         ppa_connect(dev, CONNECT_EPP_MAYBE);
 962                         ppa_reset_pulse(ppb);
 963                         udelay(1000);
 964                         ppa_disconnect(dev);
 965                         udelay(1000);
 966                         if (dev->mode == PPA_EPP_32) {
 967                                 dev->mode = old_mode;
 968                                 goto second_pass;
 969                         }
 970                         return -EIO;
 971                 }
 972                 ppa_disconnect(dev);
 973                 printk("ppa: Communication established with ID %i using %s\n",
 974                        loop, PPA_MODE_STRING[dev->mode]);
 975                 ppa_connect(dev, CONNECT_EPP_MAYBE);
 976                 ppa_reset_pulse(ppb);
 977                 udelay(1000);
 978                 ppa_disconnect(dev);
 979                 udelay(1000);
 980                 return 0;
 981         }
 982         return -ENODEV;
 983 }
 984
 985 static struct scsi_host_template ppa_template = {
 986         .module                 = THIS_MODULE,
 987         .proc_name              = "ppa",
 988         .proc_info              = ppa_proc_info,
 989         .name                   = "Iomega VPI0 (ppa) interface",
 990         .queuecommand           = ppa_queuecommand,
 991         .eh_abort_handler       = ppa_abort,
 992         .eh_bus_reset_handler   = ppa_reset,
 993         .eh_host_reset_handler  = ppa_reset,
 994         .bios_param             = ppa_biosparam,
 995         .this_id                = -1,
 996         .sg_tablesize           = SG_ALL,
 997         .cmd_per_lun            = 1,
 998         .use_clustering         = ENABLE_CLUSTERING,
 999         .can_queue              = 1,
1000 };
1001
1002 /***************************************************************************
1003  *                   Parallel port probing routines                        *
1004  ***************************************************************************/
1005
1006 static LIST_HEAD(ppa_hosts);
1007
1008 static int __ppa_attach(struct parport *pb)
1009 {
1010         struct Scsi_Host *host;
1011         DECLARE_WAIT_QUEUE_HEAD(waiting);
1012         DEFINE_WAIT(wait);
1013         ppa_struct *dev;
1014         int ports;
1015         int modes, ppb, ppb_hi;
1016         int err = -ENOMEM;
1017
1018         dev = kmalloc(sizeof(ppa_struct), GFP_KERNEL);
1019         if (!dev)
1020                 return -ENOMEM;
1021         memset(dev, 0, sizeof(ppa_struct));
1022         dev->base = -1;
1023         dev->mode = PPA_AUTODETECT;
1024         dev->recon_tmo = PPA_RECON_TMO;
1025         init_waitqueue_head(&waiting);
1026         dev->dev = parport_register_device(pb, "ppa", NULL, ppa_wakeup,
1027                                             NULL, 0, dev);
1028
1029         if (!dev->dev)
1030                 goto out;
1031
1032         /* Claim the bus so it remembers what we do to the control
1033          * registers. [ CTR and ECP ]
1034          */
1035         err = -EBUSY;
1036         dev->waiting = &waiting;
1037         prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1038         if (ppa_pb_claim(dev))
1039                 schedule_timeout(3 * HZ);
1040         if (dev->wanted) {
1041                 printk(KERN_ERR "ppa%d: failed to claim parport because "
1042                                 "a pardevice is owning the port for too long "
1043                                 "time!\n", pb->number);
1044                 ppa_pb_dismiss(dev);
1045                 dev->waiting = NULL;
1046                 finish_wait(&waiting, &wait);
1047                 goto out1;
1048         }
1049         dev->waiting = NULL;
1050         finish_wait(&waiting, &wait);
1051         ppb = dev->base = dev->dev->port->base;
1052         ppb_hi = dev->dev->port->base_hi;
1053         w_ctr(ppb, 0x0c);
1054         modes = dev->dev->port->modes;
1055
1056         /* Mode detection works up the chain of speed
1057          * This avoids a nasty if-then-else-if-... tree
1058          */
1059         dev->mode = PPA_NIBBLE;
1060
1061         if (modes & PARPORT_MODE_TRISTATE)
1062                 dev->mode = PPA_PS2;
1063
1064         if (modes & PARPORT_MODE_ECP) {
1065                 w_ecr(ppb_hi, 0x20);
1066                 dev->mode = PPA_PS2;
1067         }
1068         if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))
1069                 w_ecr(ppb_hi, 0x80);
1070
1071         /* Done configuration */
1072
1073         err = ppa_init(dev);
1074         ppa_pb_release(dev);
1075
1076         if (err)
1077                 goto out1;
1078
1079         /* now the glue ... */
1080         if (dev->mode == PPA_NIBBLE || dev->mode == PPA_PS2)
1081                 ports = 3;
1082         else
1083                 ports = 8;
1084
1085         INIT_WORK(&dev->ppa_tq, ppa_interrupt, dev);
1086
1087         err = -ENOMEM;
1088         host = scsi_host_alloc(&ppa_template, sizeof(ppa_struct *));
1089         if (!host)
1090                 goto out1;
1091         host->io_port = pb->base;
1092         host->n_io_port = ports;
1093         host->dma_channel = -1;
1094         host->unique_id = pb->number;
1095         *(ppa_struct **)&host->hostdata = dev;
1096         dev->host = host;
1097         list_add_tail(&dev->list, &ppa_hosts);
1098         err = scsi_add_host(host, NULL);
1099         if (err)
1100                 goto out2;
1101         scsi_scan_host(host);
1102         return 0;
1103 out2:
1104         list_del_init(&dev->list);
1105         scsi_host_put(host);
1106 out1:
1107         parport_unregister_device(dev->dev);
1108 out:
1109         kfree(dev);
1110         return err;
1111 }
1112
1113 static void ppa_attach(struct parport *pb)
1114 {
1115         __ppa_attach(pb);
1116 }
1117
1118 static void ppa_detach(struct parport *pb)
1119 {
1120         ppa_struct *dev;
1121         list_for_each_entry(dev, &ppa_hosts, list) {
1122                 if (dev->dev->port == pb) {
1123                         list_del_init(&dev->list);
1124                         scsi_remove_host(dev->host);
1125                         scsi_host_put(dev->host);
1126                         parport_unregister_device(dev->dev);
1127                         kfree(dev);
1128                         break;
1129                 }
1130         }
1131 }
1132
1133 static struct parport_driver ppa_driver = {
1134         .name   = "ppa",
1135         .attach = ppa_attach,
1136         .detach = ppa_detach,
1137 };
1138
1139 static int __init ppa_driver_init(void)
1140 {
1141         printk("ppa: Version %s\n", PPA_VERSION);
1142         return parport_register_driver(&ppa_driver);
1143 }
1144
1145 static void __exit ppa_driver_exit(void)
1146 {
1147         parport_unregister_driver(&ppa_driver);
1148 }
1149
1150 module_init(ppa_driver_init);
1151 module_exit(ppa_driver_exit);
1152 MODULE_LICENSE("GPL");