git.oblomov.eu Git - linux-2.6/blob - 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 <asm/io.h>
  22
  23 #include <scsi/scsi.h>
  24 #include <scsi/scsi_cmnd.h>
  25 #include <scsi/scsi_device.h>
  26 #include <scsi/scsi_host.h>
  27
  28
  29 static void ppa_reset_pulse(unsigned int base);
  30
  31 typedef struct {
  32         struct pardevice *dev;  /* Parport device entry         */
  33         int base;               /* Actual port address          */
  34         int mode;               /* Transfer mode                */
  35         struct scsi_cmnd *cur_cmd;      /* Current queued command       */
  36         struct work_struct ppa_tq;      /* Polling interrupt stuff       */
  37         unsigned long jstart;   /* Jiffies at start             */
  38         unsigned long recon_tmo;        /* How many usecs to wait for reconnection (6th bit) */
  39         unsigned int failed:1;  /* Failure flag                 */
  40         unsigned wanted:1;      /* Parport sharing busy flag    */
  41         wait_queue_head_t *waiting;
  42         struct Scsi_Host *host;
  43         struct list_head list;
  44 } ppa_struct;
  45
  46 #include  "ppa.h"
  47
  48 static inline ppa_struct *ppa_dev(struct Scsi_Host *host)
  49 {
  50         return *(ppa_struct **)&host->hostdata;
  51 }
  52
  53 static DEFINE_SPINLOCK(arbitration_lock);
  54
  55 static void got_it(ppa_struct *dev)
  56 {
  57         dev->base = dev->dev->port->base;
  58         if (dev->cur_cmd)
  59                 dev->cur_cmd->SCp.phase = 1;
  60         else
  61                 wake_up(dev->waiting);
  62 }
  63
  64 static void ppa_wakeup(void *ref)
  65 {
  66         ppa_struct *dev = (ppa_struct *) ref;
  67         unsigned long flags;
  68
  69         spin_lock_irqsave(&arbitration_lock, flags);
  70         if (dev->wanted) {
  71                 parport_claim(dev->dev);
  72                 got_it(dev);
  73                 dev->wanted = 0;
  74         }
  75         spin_unlock_irqrestore(&arbitration_lock, flags);
  76         return;
  77 }
  78
  79 static int ppa_pb_claim(ppa_struct *dev)
  80 {
  81         unsigned long flags;
  82         int res = 1;
  83         spin_lock_irqsave(&arbitration_lock, flags);
  84         if (parport_claim(dev->dev) == 0) {
  85                 got_it(dev);
  86                 res = 0;
  87         }
  88         dev->wanted = res;
  89         spin_unlock_irqrestore(&arbitration_lock, flags);
  90         return res;
  91 }
  92
  93 static void ppa_pb_dismiss(ppa_struct *dev)
  94 {
  95         unsigned long flags;
  96         int wanted;
  97         spin_lock_irqsave(&arbitration_lock, flags);
  98         wanted = dev->wanted;
  99         dev->wanted = 0;
 100         spin_unlock_irqrestore(&arbitration_lock, flags);
 101         if (!wanted)
 102                 parport_release(dev->dev);
 103 }
 104
 105 static inline void ppa_pb_release(ppa_struct *dev)
 106 {
 107         parport_release(dev->dev);
 108 }
 109
 110 /*
 111  * Start of Chipset kludges
 112  */
 113
 114 /* This is to give the ppa driver a way to modify the timings (and other
 115  * parameters) by writing to the /proc/scsi/ppa/0 file.
 116  * Very simple method really... (To simple, no error checking :( )
 117  * Reason: Kernel hackers HATE having to unload and reload modules for
 118  * testing...
 119  * Also gives a method to use a script to obtain optimum timings (TODO)
 120  */
 121
 122 static inline int ppa_proc_write(ppa_struct *dev, char *buffer, int length)
 123 {
 124         unsigned long x;
 125
 126         if ((length > 5) && (strncmp(buffer, "mode=", 5) == 0)) {
 127                 x = simple_strtoul(buffer + 5, NULL, 0);
 128                 dev->mode = x;
 129                 return length;
 130         }
 131         if ((length > 10) && (strncmp(buffer, "recon_tmo=", 10) == 0)) {
 132                 x = simple_strtoul(buffer + 10, NULL, 0);
 133                 dev->recon_tmo = x;
 134                 printk("ppa: recon_tmo set to %ld\n", x);
 135                 return length;
 136         }
 137         printk("ppa /proc: invalid variable\n");
 138         return (-EINVAL);
 139 }
 140
 141 static int ppa_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset, int length, int inout)
 142 {
 143         int len = 0;
 144         ppa_struct *dev = ppa_dev(host);
 145
 146         if (inout)
 147                 return ppa_proc_write(dev, buffer, length);
 148
 149         len += sprintf(buffer + len, "Version : %s\n", PPA_VERSION);
 150         len +=
 151             sprintf(buffer + len, "Parport : %s\n",
 152                     dev->dev->port->name);
 153         len +=
 154             sprintf(buffer + len, "Mode    : %s\n",
 155                     PPA_MODE_STRING[dev->mode]);
 156 #if PPA_DEBUG > 0
 157         len +=
 158             sprintf(buffer + len, "recon_tmo : %lu\n", dev->recon_tmo);
 159 #endif
 160
 161         /* Request for beyond end of buffer */
 162         if (offset > length)
 163                 return 0;
 164
 165         *start = buffer + offset;
 166         len -= offset;
 167         if (len > length)
 168                 len = length;
 169         return len;
 170 }
 171
 172 static int device_check(ppa_struct *dev);
 173
 174 #if PPA_DEBUG > 0
 175 #define ppa_fail(x,y) printk("ppa: ppa_fail(%i) from %s at line %d\n",\
 176            y, __FUNCTION__, __LINE__); ppa_fail_func(x,y);
 177 static inline void ppa_fail_func(ppa_struct *dev, int error_code)
 178 #else
 179 static inline void ppa_fail(ppa_struct *dev, int error_code)
 180 #endif
 181 {
 182         /* If we fail a device then we trash status / message bytes */
 183         if (dev->cur_cmd) {
 184                 dev->cur_cmd->result = error_code << 16;
 185                 dev->failed = 1;
 186         }
 187 }
 188
 189 /*
 190  * Wait for the high bit to be set.
 191  *
 192  * In principle, this could be tied to an interrupt, but the adapter
 193  * doesn't appear to be designed to support interrupts.  We spin on
 194  * the 0x80 ready bit.
 195  */
 196 static unsigned char ppa_wait(ppa_struct *dev)
 197 {
 198         int k;
 199         unsigned short ppb = dev->base;
 200         unsigned char r;
 201
 202         k = PPA_SPIN_TMO;
 203         /* Wait for bit 6 and 7 - PJC */
 204         for (r = r_str(ppb); ((r & 0xc0) != 0xc0) && (k); k--) {
 205                 udelay(1);
 206                 r = r_str(ppb);
 207         }
 208
 209         /*
 210          * return some status information.
 211          * Semantics: 0xc0 = ZIP wants more data
 212          *            0xd0 = ZIP wants to send more data
 213          *            0xe0 = ZIP is expecting SCSI command data
 214          *            0xf0 = end of transfer, ZIP is sending status
 215          */
 216         if (k)
 217                 return (r & 0xf0);
 218
 219         /* Counter expired - Time out occurred */
 220         ppa_fail(dev, DID_TIME_OUT);
 221         printk("ppa timeout in ppa_wait\n");
 222         return 0;               /* command timed out */
 223 }
 224
 225 /*
 226  * Clear EPP Timeout Bit
 227  */
 228 static inline void epp_reset(unsigned short ppb)
 229 {
 230         int i;
 231
 232         i = r_str(ppb);
 233         w_str(ppb, i);
 234         w_str(ppb, i & 0xfe);
 235 }
 236
 237 /*
 238  * Wait for empty ECP fifo (if we are in ECP fifo mode only)
 239  */
 240 static inline void ecp_sync(ppa_struct *dev)
 241 {
 242         int i, ppb_hi = dev->dev->port->base_hi;
 243
 244         if (ppb_hi == 0)
 245                 return;
 246
 247         if ((r_ecr(ppb_hi) & 0xe0) == 0x60) {   /* mode 011 == ECP fifo mode */
 248                 for (i = 0; i < 100; i++) {
 249                         if (r_ecr(ppb_hi) & 0x01)
 250                                 return;
 251                         udelay(5);
 252                 }
 253                 printk("ppa: ECP sync failed as data still present in FIFO.\n");
 254         }
 255 }
 256
 257 static int ppa_byte_out(unsigned short base, const char *buffer, int len)
 258 {
 259         int i;
 260
 261         for (i = len; i; i--) {
 262                 w_dtr(base, *buffer++);
 263                 w_ctr(base, 0xe);
 264                 w_ctr(base, 0xc);
 265         }
 266         return 1;               /* All went well - we hope! */
 267 }
 268
 269 static int ppa_byte_in(unsigned short base, char *buffer, int len)
 270 {
 271         int i;
 272
 273         for (i = len; i; i--) {
 274                 *buffer++ = r_dtr(base);
 275                 w_ctr(base, 0x27);
 276                 w_ctr(base, 0x25);
 277         }
 278         return 1;               /* All went well - we hope! */
 279 }
 280
 281 static int ppa_nibble_in(unsigned short base, char *buffer, int len)
 282 {
 283         for (; len; len--) {
 284                 unsigned char h;
 285
 286                 w_ctr(base, 0x4);
 287                 h = r_str(base) & 0xf0;
 288                 w_ctr(base, 0x6);
 289                 *buffer++ = h | ((r_str(base) & 0xf0) >> 4);
 290         }
 291         return 1;               /* All went well - we hope! */
 292 }
 293
 294 static int ppa_out(ppa_struct *dev, char *buffer, int len)
 295 {
 296         int r;
 297         unsigned short ppb = dev->base;
 298
 299         r = ppa_wait(dev);
 300
 301         if ((r & 0x50) != 0x40) {
 302                 ppa_fail(dev, DID_ERROR);
 303                 return 0;
 304         }
 305         switch (dev->mode) {
 306         case PPA_NIBBLE:
 307         case PPA_PS2:
 308                 /* 8 bit output, with a loop */
 309                 r = ppa_byte_out(ppb, buffer, len);
 310                 break;
 311
 312         case PPA_EPP_32:
 313         case PPA_EPP_16:
 314         case PPA_EPP_8:
 315                 epp_reset(ppb);
 316                 w_ctr(ppb, 0x4);
 317 #ifdef CONFIG_SCSI_IZIP_EPP16
 318                 if (!(((long) buffer | len) & 0x01))
 319                         outsw(ppb + 4, buffer, len >> 1);
 320 #else
 321                 if (!(((long) buffer | len) & 0x03))
 322                         outsl(ppb + 4, buffer, len >> 2);
 323 #endif
 324                 else
 325                         outsb(ppb + 4, buffer, len);
 326                 w_ctr(ppb, 0xc);
 327                 r = !(r_str(ppb) & 0x01);
 328                 w_ctr(ppb, 0xc);
 329                 ecp_sync(dev);
 330                 break;
 331
 332         default:
 333                 printk("PPA: bug in ppa_out()\n");
 334                 r = 0;
 335         }
 336         return r;
 337 }
 338
 339 static int ppa_in(ppa_struct *dev, char *buffer, int len)
 340 {
 341         int r;
 342         unsigned short ppb = dev->base;
 343
 344         r = ppa_wait(dev);
 345
 346         if ((r & 0x50) != 0x50) {
 347                 ppa_fail(dev, DID_ERROR);
 348                 return 0;
 349         }
 350         switch (dev->mode) {
 351         case PPA_NIBBLE:
 352                 /* 4 bit input, with a loop */
 353                 r = ppa_nibble_in(ppb, buffer, len);
 354                 w_ctr(ppb, 0xc);
 355                 break;
 356
 357         case PPA_PS2:
 358                 /* 8 bit input, with a loop */
 359                 w_ctr(ppb, 0x25);
 360                 r = ppa_byte_in(ppb, buffer, len);
 361                 w_ctr(ppb, 0x4);
 362                 w_ctr(ppb, 0xc);
 363                 break;
 364
 365         case PPA_EPP_32:
 366         case PPA_EPP_16:
 367         case PPA_EPP_8:
 368                 epp_reset(ppb);
 369                 w_ctr(ppb, 0x24);
 370 #ifdef CONFIG_SCSI_IZIP_EPP16
 371                 if (!(((long) buffer | len) & 0x01))
 372                         insw(ppb + 4, buffer, len >> 1);
 373 #else
 374                 if (!(((long) buffer | len) & 0x03))
 375                         insl(ppb + 4, buffer, len >> 2);
 376 #endif
 377                 else
 378                         insb(ppb + 4, buffer, len);
 379                 w_ctr(ppb, 0x2c);
 380                 r = !(r_str(ppb) & 0x01);
 381                 w_ctr(ppb, 0x2c);
 382                 ecp_sync(dev);
 383                 break;
 384
 385         default:
 386                 printk("PPA: bug in ppa_ins()\n");
 387                 r = 0;
 388                 break;
 389         }
 390         return r;
 391 }
 392
 393 /* end of ppa_io.h */
 394 static inline void ppa_d_pulse(unsigned short ppb, unsigned char b)
 395 {
 396         w_dtr(ppb, b);
 397         w_ctr(ppb, 0xc);
 398         w_ctr(ppb, 0xe);
 399         w_ctr(ppb, 0xc);
 400         w_ctr(ppb, 0x4);
 401         w_ctr(ppb, 0xc);
 402 }
 403
 404 static void ppa_disconnect(ppa_struct *dev)
 405 {
 406         unsigned short ppb = dev->base;
 407
 408         ppa_d_pulse(ppb, 0);
 409         ppa_d_pulse(ppb, 0x3c);
 410         ppa_d_pulse(ppb, 0x20);
 411         ppa_d_pulse(ppb, 0xf);
 412 }
 413
 414 static inline void ppa_c_pulse(unsigned short ppb, unsigned char b)
 415 {
 416         w_dtr(ppb, b);
 417         w_ctr(ppb, 0x4);
 418         w_ctr(ppb, 0x6);
 419         w_ctr(ppb, 0x4);
 420         w_ctr(ppb, 0xc);
 421 }
 422
 423 static inline void ppa_connect(ppa_struct *dev, int flag)
 424 {
 425         unsigned short ppb = dev->base;
 426
 427         ppa_c_pulse(ppb, 0);
 428         ppa_c_pulse(ppb, 0x3c);
 429         ppa_c_pulse(ppb, 0x20);
 430         if ((flag == CONNECT_EPP_MAYBE) && IN_EPP_MODE(dev->mode))
 431                 ppa_c_pulse(ppb, 0xcf);
 432         else
 433                 ppa_c_pulse(ppb, 0x8f);
 434 }
 435
 436 static int ppa_select(ppa_struct *dev, int target)
 437 {
 438         int k;
 439         unsigned short ppb = dev->base;
 440
 441         /*
 442          * Bit 6 (0x40) is the device selected bit.
 443          * First we must wait till the current device goes off line...
 444          */
 445         k = PPA_SELECT_TMO;
 446         do {
 447                 k--;
 448                 udelay(1);
 449         } while ((r_str(ppb) & 0x40) && (k));
 450         if (!k)
 451                 return 0;
 452
 453         w_dtr(ppb, (1 << target));
 454         w_ctr(ppb, 0xe);
 455         w_ctr(ppb, 0xc);
 456         w_dtr(ppb, 0x80);       /* This is NOT the initator */
 457         w_ctr(ppb, 0x8);
 458
 459         k = PPA_SELECT_TMO;
 460         do {
 461                 k--;
 462                 udelay(1);
 463         }
 464         while (!(r_str(ppb) & 0x40) && (k));
 465         if (!k)
 466                 return 0;
 467
 468         return 1;
 469 }
 470
 471 /*
 472  * This is based on a trace of what the Iomega DOS 'guest' driver does.
 473  * I've tried several different kinds of parallel ports with guest and
 474  * coded this to react in the same ways that it does.
 475  *
 476  * The return value from this function is just a hint about where the
 477  * handshaking failed.
 478  *
 479  */
 480 static int ppa_init(ppa_struct *dev)
 481 {
 482         int retv;
 483         unsigned short ppb = dev->base;
 484
 485         ppa_disconnect(dev);
 486         ppa_connect(dev, CONNECT_NORMAL);
 487
 488         retv = 2;               /* Failed */
 489
 490         w_ctr(ppb, 0xe);
 491         if ((r_str(ppb) & 0x08) == 0x08)
 492                 retv--;
 493
 494         w_ctr(ppb, 0xc);
 495         if ((r_str(ppb) & 0x08) == 0x00)
 496                 retv--;
 497
 498         if (!retv)
 499                 ppa_reset_pulse(ppb);
 500         udelay(1000);           /* Allow devices to settle down */
 501         ppa_disconnect(dev);
 502         udelay(1000);           /* Another delay to allow devices to settle */
 503
 504         if (retv)
 505                 return -EIO;
 506
 507         return device_check(dev);
 508 }
 509
 510 static inline int ppa_send_command(struct scsi_cmnd *cmd)
 511 {
 512         ppa_struct *dev = ppa_dev(cmd->device->host);
 513         int k;
 514
 515         w_ctr(dev->base, 0x0c);
 516
 517         for (k = 0; k < cmd->cmd_len; k++)
 518                 if (!ppa_out(dev, &cmd->cmnd[k], 1))
 519                         return 0;
 520         return 1;
 521 }
 522
 523 /*
 524  * The bulk flag enables some optimisations in the data transfer loops,
 525  * it should be true for any command that transfers data in integral
 526  * numbers of sectors.
 527  *
 528  * The driver appears to remain stable if we speed up the parallel port
 529  * i/o in this function, but not elsewhere.
 530  */
 531 static int ppa_completion(struct scsi_cmnd *cmd)
 532 {
 533         /* Return codes:
 534          * -1     Error
 535          *  0     Told to schedule
 536          *  1     Finished data transfer
 537          */
 538         ppa_struct *dev = ppa_dev(cmd->device->host);
 539         unsigned short ppb = dev->base;
 540         unsigned long start_jiffies = jiffies;
 541
 542         unsigned char r, v;
 543         int fast, bulk, status;
 544
 545         v = cmd->cmnd[0];
 546         bulk = ((v == READ_6) ||
 547                 (v == READ_10) || (v == WRITE_6) || (v == WRITE_10));
 548
 549         /*
 550          * We only get here if the drive is ready to comunicate,
 551          * hence no need for a full ppa_wait.
 552          */
 553         r = (r_str(ppb) & 0xf0);
 554
 555         while (r != (unsigned char) 0xf0) {
 556                 /*
 557                  * If we have been running for more than a full timer tick
 558                  * then take a rest.
 559                  */
 560                 if (time_after(jiffies, start_jiffies + 1))
 561                         return 0;
 562
 563                 if ((cmd->SCp.this_residual <= 0)) {
 564                         ppa_fail(dev, DID_ERROR);
 565                         return -1;      /* ERROR_RETURN */
 566                 }
 567
 568                 /* On some hardware we have SCSI disconnected (6th bit low)
 569                  * for about 100usecs. It is too expensive to wait a
 570                  * tick on every loop so we busy wait for no more than
 571                  * 500usecs to give the drive a chance first. We do not
 572                  * change things for "normal" hardware since generally
 573                  * the 6th bit is always high.
 574                  * This makes the CPU load higher on some hardware
 575                  * but otherwise we can not get more than 50K/secs
 576                  * on this problem hardware.
 577                  */
 578                 if ((r & 0xc0) != 0xc0) {
 579                         /* Wait for reconnection should be no more than
 580                          * jiffy/2 = 5ms = 5000 loops
 581                          */
 582                         unsigned long k = dev->recon_tmo;
 583                         for (; k && ((r = (r_str(ppb) & 0xf0)) & 0xc0) != 0xc0;
 584                              k--)
 585                                 udelay(1);
 586
 587                         if (!k)
 588                                 return 0;
 589                 }
 590
 591                 /* determine if we should use burst I/O */
 592                 fast = (bulk && (cmd->SCp.this_residual >= PPA_BURST_SIZE))
 593                     ? PPA_BURST_SIZE : 1;
 594
 595                 if (r == (unsigned char) 0xc0)
 596                         status = ppa_out(dev, cmd->SCp.ptr, fast);
 597                 else
 598                         status = ppa_in(dev, cmd->SCp.ptr, fast);
 599
 600                 cmd->SCp.ptr += fast;
 601                 cmd->SCp.this_residual -= fast;
 602
 603                 if (!status) {
 604                         ppa_fail(dev, DID_BUS_BUSY);
 605                         return -1;      /* ERROR_RETURN */
 606                 }
 607                 if (cmd->SCp.buffer && !cmd->SCp.this_residual) {
 608                         /* if scatter/gather, advance to the next segment */
 609                         if (cmd->SCp.buffers_residual--) {
 610                                 cmd->SCp.buffer++;
 611                                 cmd->SCp.this_residual =
 612                                     cmd->SCp.buffer->length;
 613                                 cmd->SCp.ptr =
 614                                     page_address(cmd->SCp.buffer->page) +
 615                                     cmd->SCp.buffer->offset;
 616                         }
 617                 }
 618                 /* Now check to see if the drive is ready to comunicate */
 619                 r = (r_str(ppb) & 0xf0);
 620                 /* If not, drop back down to the scheduler and wait a timer tick */
 621                 if (!(r & 0x80))
 622                         return 0;
 623         }
 624         return 1;               /* FINISH_RETURN */
 625 }
 626
 627 /*
 628  * Since the PPA itself doesn't generate interrupts, we use
 629  * the scheduler's task queue to generate a stream of call-backs and
 630  * complete the request when the drive is ready.
 631  */
 632 static void ppa_interrupt(void *data)
 633 {
 634         ppa_struct *dev = (ppa_struct *) data;
 635         struct scsi_cmnd *cmd = dev->cur_cmd;
 636
 637         if (!cmd) {
 638                 printk("PPA: bug in ppa_interrupt\n");
 639                 return;
 640         }
 641         if (ppa_engine(dev, cmd)) {
 642                 dev->ppa_tq.data = (void *) dev;
 643                 schedule_delayed_work(&dev->ppa_tq, 1);
 644                 return;
 645         }
 646         /* Command must of completed hence it is safe to let go... */
 647 #if PPA_DEBUG > 0
 648         switch ((cmd->result >> 16) & 0xff) {
 649         case DID_OK:
 650                 break;
 651         case DID_NO_CONNECT:
 652                 printk("ppa: no device at SCSI ID %i\n", cmd->device->target);
 653                 break;
 654         case DID_BUS_BUSY:
 655                 printk("ppa: BUS BUSY - EPP timeout detected\n");
 656                 break;
 657         case DID_TIME_OUT:
 658                 printk("ppa: unknown timeout\n");
 659                 break;
 660         case DID_ABORT:
 661                 printk("ppa: told to abort\n");
 662                 break;
 663         case DID_PARITY:
 664                 printk("ppa: parity error (???)\n");
 665                 break;
 666         case DID_ERROR:
 667                 printk("ppa: internal driver error\n");
 668                 break;
 669         case DID_RESET:
 670                 printk("ppa: told to reset device\n");
 671                 break;
 672         case DID_BAD_INTR:
 673                 printk("ppa: bad interrupt (???)\n");
 674                 break;
 675         default:
 676                 printk("ppa: bad return code (%02x)\n",
 677                        (cmd->result >> 16) & 0xff);
 678         }
 679 #endif
 680
 681         if (cmd->SCp.phase > 1)
 682                 ppa_disconnect(dev);
 683
 684         ppa_pb_dismiss(dev);
 685
 686         dev->cur_cmd = NULL;
 687
 688         cmd->scsi_done(cmd);
 689 }
 690
 691 static int ppa_engine(ppa_struct *dev, struct scsi_cmnd *cmd)
 692 {
 693         unsigned short ppb = dev->base;
 694         unsigned char l = 0, h = 0;
 695         int retv;
 696
 697         /* First check for any errors that may of occurred
 698          * Here we check for internal errors
 699          */
 700         if (dev->failed)
 701                 return 0;
 702
 703         switch (cmd->SCp.phase) {
 704         case 0:         /* Phase 0 - Waiting for parport */
 705                 if (time_after(jiffies, dev->jstart + HZ)) {
 706                         /*
 707                          * We waited more than a second
 708                          * for parport to call us
 709                          */
 710                         ppa_fail(dev, DID_BUS_BUSY);
 711                         return 0;
 712                 }
 713                 return 1;       /* wait until ppa_wakeup claims parport */
 714         case 1:         /* Phase 1 - Connected */
 715                 {               /* Perform a sanity check for cable unplugged */
 716                         int retv = 2;   /* Failed */
 717
 718                         ppa_connect(dev, CONNECT_EPP_MAYBE);
 719
 720                         w_ctr(ppb, 0xe);
 721                         if ((r_str(ppb) & 0x08) == 0x08)
 722                                 retv--;
 723
 724                         w_ctr(ppb, 0xc);
 725                         if ((r_str(ppb) & 0x08) == 0x00)
 726                                 retv--;
 727
 728                         if (retv) {
 729                                 if ((jiffies - dev->jstart) > (1 * HZ)) {
 730                                         printk
 731                                             ("ppa: Parallel port cable is unplugged!!\n");
 732                                         ppa_fail(dev, DID_BUS_BUSY);
 733                                         return 0;
 734                                 } else {
 735                                         ppa_disconnect(dev);
 736                                         return 1;       /* Try again in a jiffy */
 737                                 }
 738                         }
 739                         cmd->SCp.phase++;
 740                 }
 741
 742         case 2:         /* Phase 2 - We are now talking to the scsi bus */
 743                 if (!ppa_select(dev, scmd_id(cmd))) {
 744                         ppa_fail(dev, DID_NO_CONNECT);
 745                         return 0;
 746                 }
 747                 cmd->SCp.phase++;
 748
 749         case 3:         /* Phase 3 - Ready to accept a command */
 750                 w_ctr(ppb, 0x0c);
 751                 if (!(r_str(ppb) & 0x80))
 752                         return 1;
 753
 754                 if (!ppa_send_command(cmd))
 755                         return 0;
 756                 cmd->SCp.phase++;
 757
 758         case 4:         /* Phase 4 - Setup scatter/gather buffers */
 759                 if (cmd->use_sg) {
 760                         /* if many buffers are available, start filling the first */
 761                         cmd->SCp.buffer =
 762                             (struct scatterlist *) cmd->request_buffer;
 763                         cmd->SCp.this_residual = cmd->SCp.buffer->length;
 764                         cmd->SCp.ptr =
 765                             page_address(cmd->SCp.buffer->page) +
 766                             cmd->SCp.buffer->offset;
 767                 } else {
 768                         /* else fill the only available buffer */
 769                         cmd->SCp.buffer = NULL;
 770                         cmd->SCp.this_residual = cmd->request_bufflen;
 771                         cmd->SCp.ptr = cmd->request_buffer;
 772                 }
 773                 cmd->SCp.buffers_residual = cmd->use_sg - 1;
 774                 cmd->SCp.phase++;
 775
 776         case 5:         /* Phase 5 - Data transfer stage */
 777                 w_ctr(ppb, 0x0c);
 778                 if (!(r_str(ppb) & 0x80))
 779                         return 1;
 780
 781                 retv = ppa_completion(cmd);
 782                 if (retv == -1)
 783                         return 0;
 784                 if (retv == 0)
 785                         return 1;
 786                 cmd->SCp.phase++;
 787
 788         case 6:         /* Phase 6 - Read status/message */
 789                 cmd->result = DID_OK << 16;
 790                 /* Check for data overrun */
 791                 if (ppa_wait(dev) != (unsigned char) 0xf0) {
 792                         ppa_fail(dev, DID_ERROR);
 793                         return 0;
 794                 }
 795                 if (ppa_in(dev, &l, 1)) {       /* read status byte */
 796                         /* Check for optional message byte */
 797                         if (ppa_wait(dev) == (unsigned char) 0xf0)
 798                                 ppa_in(dev, &h, 1);
 799                         cmd->result =
 800                             (DID_OK << 16) + (h << 8) + (l & STATUS_MASK);
 801                 }
 802                 return 0;       /* Finished */
 803                 break;
 804
 805         default:
 806                 printk("ppa: Invalid scsi phase\n");
 807         }
 808         return 0;
 809 }
 810
 811 static int ppa_queuecommand(struct scsi_cmnd *cmd,
 812                 void (*done) (struct scsi_cmnd *))
 813 {
 814         ppa_struct *dev = ppa_dev(cmd->device->host);
 815
 816         if (dev->cur_cmd) {
 817                 printk("PPA: bug in ppa_queuecommand\n");
 818                 return 0;
 819         }
 820         dev->failed = 0;
 821         dev->jstart = jiffies;
 822         dev->cur_cmd = cmd;
 823         cmd->scsi_done = done;
 824         cmd->result = DID_ERROR << 16;  /* default return code */
 825         cmd->SCp.phase = 0;     /* bus free */
 826
 827         dev->ppa_tq.data = dev;
 828         schedule_work(&dev->ppa_tq);
 829
 830         ppa_pb_claim(dev);
 831
 832         return 0;
 833 }
 834
 835 /*
 836  * Apparently the disk->capacity attribute is off by 1 sector
 837  * for all disk drives.  We add the one here, but it should really
 838  * be done in sd.c.  Even if it gets fixed there, this will still
 839  * work.
 840  */
 841 static int ppa_biosparam(struct scsi_device *sdev, struct block_device *dev,
 842               sector_t capacity, int ip[])
 843 {
 844         ip[0] = 0x40;
 845         ip[1] = 0x20;
 846         ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
 847         if (ip[2] > 1024) {
 848                 ip[0] = 0xff;
 849                 ip[1] = 0x3f;
 850                 ip[2] = ((unsigned long) capacity + 1) / (ip[0] * ip[1]);
 851                 if (ip[2] > 1023)
 852                         ip[2] = 1023;
 853         }
 854         return 0;
 855 }
 856
 857 static int ppa_abort(struct scsi_cmnd *cmd)
 858 {
 859         ppa_struct *dev = ppa_dev(cmd->device->host);
 860         /*
 861          * There is no method for aborting commands since Iomega
 862          * have tied the SCSI_MESSAGE line high in the interface
 863          */
 864
 865         switch (cmd->SCp.phase) {
 866         case 0:         /* Do not have access to parport */
 867         case 1:         /* Have not connected to interface */
 868                 dev->cur_cmd = NULL;    /* Forget the problem */
 869                 return SUCCESS;
 870                 break;
 871         default:                /* SCSI command sent, can not abort */
 872                 return FAILED;
 873                 break;
 874         }
 875 }
 876
 877 static void ppa_reset_pulse(unsigned int base)
 878 {
 879         w_dtr(base, 0x40);
 880         w_ctr(base, 0x8);
 881         udelay(30);
 882         w_ctr(base, 0xc);
 883 }
 884
 885 static int ppa_reset(struct scsi_cmnd *cmd)
 886 {
 887         ppa_struct *dev = ppa_dev(cmd->device->host);
 888
 889         if (cmd->SCp.phase)
 890                 ppa_disconnect(dev);
 891         dev->cur_cmd = NULL;    /* Forget the problem */
 892
 893         ppa_connect(dev, CONNECT_NORMAL);
 894         ppa_reset_pulse(dev->base);
 895         mdelay(1);              /* device settle delay */
 896         ppa_disconnect(dev);
 897         mdelay(1);              /* device settle delay */
 898         return SUCCESS;
 899 }
 900
 901 static int device_check(ppa_struct *dev)
 902 {
 903         /* This routine looks for a device and then attempts to use EPP
 904            to send a command. If all goes as planned then EPP is available. */
 905
 906         static char cmd[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
 907         int loop, old_mode, status, k, ppb = dev->base;
 908         unsigned char l;
 909
 910         old_mode = dev->mode;
 911         for (loop = 0; loop < 8; loop++) {
 912                 /* Attempt to use EPP for Test Unit Ready */
 913                 if ((ppb & 0x0007) == 0x0000)
 914                         dev->mode = PPA_EPP_32;
 915
 916               second_pass:
 917                 ppa_connect(dev, CONNECT_EPP_MAYBE);
 918                 /* Select SCSI device */
 919                 if (!ppa_select(dev, loop)) {
 920                         ppa_disconnect(dev);
 921                         continue;
 922                 }
 923                 printk("ppa: Found device at ID %i, Attempting to use %s\n",
 924                        loop, PPA_MODE_STRING[dev->mode]);
 925
 926                 /* Send SCSI command */
 927                 status = 1;
 928                 w_ctr(ppb, 0x0c);
 929                 for (l = 0; (l < 6) && (status); l++)
 930                         status = ppa_out(dev, cmd, 1);
 931
 932                 if (!status) {
 933                         ppa_disconnect(dev);
 934                         ppa_connect(dev, CONNECT_EPP_MAYBE);
 935                         w_dtr(ppb, 0x40);
 936                         w_ctr(ppb, 0x08);
 937                         udelay(30);
 938                         w_ctr(ppb, 0x0c);
 939                         udelay(1000);
 940                         ppa_disconnect(dev);
 941                         udelay(1000);
 942                         if (dev->mode == PPA_EPP_32) {
 943                                 dev->mode = old_mode;
 944                                 goto second_pass;
 945                         }
 946                         return -EIO;
 947                 }
 948                 w_ctr(ppb, 0x0c);
 949                 k = 1000000;    /* 1 Second */
 950                 do {
 951                         l = r_str(ppb);
 952                         k--;
 953                         udelay(1);
 954                 } while (!(l & 0x80) && (k));
 955
 956                 l &= 0xf0;
 957
 958                 if (l != 0xf0) {
 959                         ppa_disconnect(dev);
 960                         ppa_connect(dev, CONNECT_EPP_MAYBE);
 961                         ppa_reset_pulse(ppb);
 962                         udelay(1000);
 963                         ppa_disconnect(dev);
 964                         udelay(1000);
 965                         if (dev->mode == PPA_EPP_32) {
 966                                 dev->mode = old_mode;
 967                                 goto second_pass;
 968                         }
 969                         return -EIO;
 970                 }
 971                 ppa_disconnect(dev);
 972                 printk("ppa: Communication established with ID %i using %s\n",
 973                        loop, PPA_MODE_STRING[dev->mode]);
 974                 ppa_connect(dev, CONNECT_EPP_MAYBE);
 975                 ppa_reset_pulse(ppb);
 976                 udelay(1000);
 977                 ppa_disconnect(dev);
 978                 udelay(1000);
 979                 return 0;
 980         }
 981         return -ENODEV;
 982 }
 983
 984 static struct scsi_host_template ppa_template = {
 985         .module                 = THIS_MODULE,
 986         .proc_name              = "ppa",
 987         .proc_info              = ppa_proc_info,
 988         .name                   = "Iomega VPI0 (ppa) interface",
 989         .queuecommand           = ppa_queuecommand,
 990         .eh_abort_handler       = ppa_abort,
 991         .eh_bus_reset_handler   = ppa_reset,
 992         .eh_host_reset_handler  = ppa_reset,
 993         .bios_param             = ppa_biosparam,
 994         .this_id                = -1,
 995         .sg_tablesize           = SG_ALL,
 996         .cmd_per_lun            = 1,
 997         .use_clustering         = ENABLE_CLUSTERING,
 998         .can_queue              = 1,
 999 };
1000
1001 /***************************************************************************
1002  *                   Parallel port probing routines                        *
1003  ***************************************************************************/
1004
1005 static LIST_HEAD(ppa_hosts);
1006
1007 static int __ppa_attach(struct parport *pb)
1008 {
1009         struct Scsi_Host *host;
1010         DECLARE_WAIT_QUEUE_HEAD(waiting);
1011         DEFINE_WAIT(wait);
1012         ppa_struct *dev;
1013         int ports;
1014         int modes, ppb, ppb_hi;
1015         int err = -ENOMEM;
1016
1017         dev = kmalloc(sizeof(ppa_struct), GFP_KERNEL);
1018         if (!dev)
1019                 return -ENOMEM;
1020         memset(dev, 0, sizeof(ppa_struct));
1021         dev->base = -1;
1022         dev->mode = PPA_AUTODETECT;
1023         dev->recon_tmo = PPA_RECON_TMO;
1024         init_waitqueue_head(&waiting);
1025         dev->dev = parport_register_device(pb, "ppa", NULL, ppa_wakeup,
1026                                             NULL, 0, dev);
1027
1028         if (!dev->dev)
1029                 goto out;
1030
1031         /* Claim the bus so it remembers what we do to the control
1032          * registers. [ CTR and ECP ]
1033          */
1034         err = -EBUSY;
1035         dev->waiting = &waiting;
1036         prepare_to_wait(&waiting, &wait, TASK_UNINTERRUPTIBLE);
1037         if (ppa_pb_claim(dev))
1038                 schedule_timeout(3 * HZ);
1039         if (dev->wanted) {
1040                 printk(KERN_ERR "ppa%d: failed to claim parport because "
1041                                 "a pardevice is owning the port for too long "
1042                                 "time!\n", pb->number);
1043                 ppa_pb_dismiss(dev);
1044                 dev->waiting = NULL;
1045                 finish_wait(&waiting, &wait);
1046                 goto out1;
1047         }
1048         dev->waiting = NULL;
1049         finish_wait(&waiting, &wait);
1050         ppb = dev->base = dev->dev->port->base;
1051         ppb_hi = dev->dev->port->base_hi;
1052         w_ctr(ppb, 0x0c);
1053         modes = dev->dev->port->modes;
1054
1055         /* Mode detection works up the chain of speed
1056          * This avoids a nasty if-then-else-if-... tree
1057          */
1058         dev->mode = PPA_NIBBLE;
1059
1060         if (modes & PARPORT_MODE_TRISTATE)
1061                 dev->mode = PPA_PS2;
1062
1063         if (modes & PARPORT_MODE_ECP) {
1064                 w_ecr(ppb_hi, 0x20);
1065                 dev->mode = PPA_PS2;
1066         }
1067         if ((modes & PARPORT_MODE_EPP) && (modes & PARPORT_MODE_ECP))
1068                 w_ecr(ppb_hi, 0x80);
1069
1070         /* Done configuration */
1071
1072         err = ppa_init(dev);
1073         ppa_pb_release(dev);
1074
1075         if (err)
1076                 goto out1;
1077
1078         /* now the glue ... */
1079         if (dev->mode == PPA_NIBBLE || dev->mode == PPA_PS2)
1080                 ports = 3;
1081         else
1082                 ports = 8;
1083
1084         INIT_WORK(&dev->ppa_tq, ppa_interrupt, dev);
1085
1086         err = -ENOMEM;
1087         host = scsi_host_alloc(&ppa_template, sizeof(ppa_struct *));
1088         if (!host)
1089                 goto out1;
1090         host->io_port = pb->base;
1091         host->n_io_port = ports;
1092         host->dma_channel = -1;
1093         host->unique_id = pb->number;
1094         *(ppa_struct **)&host->hostdata = dev;
1095         dev->host = host;
1096         list_add_tail(&dev->list, &ppa_hosts);
1097         err = scsi_add_host(host, NULL);
1098         if (err)
1099                 goto out2;
1100         scsi_scan_host(host);
1101         return 0;
1102 out2:
1103         list_del_init(&dev->list);
1104         scsi_host_put(host);
1105 out1:
1106         parport_unregister_device(dev->dev);
1107 out:
1108         kfree(dev);
1109         return err;
1110 }
1111
1112 static void ppa_attach(struct parport *pb)
1113 {
1114         __ppa_attach(pb);
1115 }
1116
1117 static void ppa_detach(struct parport *pb)
1118 {
1119         ppa_struct *dev;
1120         list_for_each_entry(dev, &ppa_hosts, list) {
1121                 if (dev->dev->port == pb) {
1122                         list_del_init(&dev->list);
1123                         scsi_remove_host(dev->host);
1124                         scsi_host_put(dev->host);
1125                         parport_unregister_device(dev->dev);
1126                         kfree(dev);
1127                         break;
1128                 }
1129         }
1130 }
1131
1132 static struct parport_driver ppa_driver = {
1133         .name   = "ppa",
1134         .attach = ppa_attach,
1135         .detach = ppa_detach,
1136 };
1137
1138 static int __init ppa_driver_init(void)
1139 {
1140         printk("ppa: Version %s\n", PPA_VERSION);
1141         return parport_register_driver(&ppa_driver);
1142 }
1143
1144 static void __exit ppa_driver_exit(void)
1145 {
1146         parport_unregister_driver(&ppa_driver);
1147 }
1148
1149 module_init(ppa_driver_init);
1150 module_exit(ppa_driver_exit);
1151 MODULE_LICENSE("GPL");