root/drivers/scsi/NCR5380.c

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DEFINITIONS

This source file includes following definitions.
  1. initialize_SCp
  2. NCR5380_print
  3. NCR5380_print_phase
  4. run_main
  5. should_disconnect
  6. NCR5380_set_timer
  7. NCR5380_timer_fn
  8. NCR5380_all_init
  9. probe_intr
  10. NCR5380_probe_irq
  11. NCR5380_print_options
  12. NCR5380_init
  13. NCR5380_queue_command
  14. NCR5380_main
  15. NCR5380_intr
  16. NCR5380_select
  17. NCR5380_transfer_pio
  18. NCR5380_transfer_dma
  19. NCR5380_information_transfer
  20. NCR5380_reselect
  21. NCR5380_dma_complete
  22. NCR5380_abort
  23. NCR5380_reset

   1 /* 
   2  * NCR 5380 generic driver routines.  These should make it *trivial*
   3  *      to implement 5380 SCSI drivers under Linux with a non-trantor
   4  *      architecture.
   5  *
   6  *      Note that these routines also work with NR53c400 family chips.
   7  *
   8  * Copyright 1993, Drew Eckhardt
   9  *      Visionary Computing 
  10  *      (Unix and Linux consulting and custom programming)
  11  *      drew@colorado.edu
  12  *      +1 (303) 666-5836
  13  *
  14  * DISTRIBUTION REALEASE 4. 
  15  *
  16  * For more information, please consult 
  17  *
  18  * NCR 5380 Family
  19  * SCSI Protocol Controller
  20  * Databook
  21  *
  22  * NCR Microelectronics
  23  * 1635 Aeroplaza Drive
  24  * Colorado Springs, CO 80916
  25  * 1+ (719) 578-3400
  26  * 1+ (800) 334-5454
  27  */
  28 
  29 /*
  30  * $Log: NCR5380.c,v $
  31  * Revision 1.5  1994/01/19  09:14:57  drew
  32  * Fixed udelay() hack that was being used on DATAOUT phases
  33  * instead of a propper wait for the final handshake.
  34  *
  35  * Revision 1.4  1994/01/19  06:44:25  drew
  36  * *** empty log message ***
  37  *
  38  * Revision 1.3  1994/01/19  05:24:40  drew
  39  * Added support for TCR LAST_BYTE_SENT bit.
  40  *
  41  * Revision 1.2  1994/01/15  06:14:11  drew
  42  * REAL DMA support, bug fixes.
  43  *
  44  * Revision 1.1  1994/01/15  06:00:54  drew
  45  * Initial revision
  46  *
  47  */
  48 
  49 /*
  50  * Furthur development / testing that should be done : 
  51  * 1.  Cleanup the NCR5380_transfer_dma function and DMA operation complete
  52  *     code so that everything does the same thing that's done at the 
  53  *     end of a pseudo-DMA read operation.
  54  *
  55  * 2.  Fix REAL_DMA (interrupt driven, polled works fine) -
  56  *     basically, transfer size needs to be reduced by one 
  57  *     and the last byte read as is done with PSEUDO_DMA.
  58  * 
  59  * 3.  Test USLEEP code 
  60  *
  61  * 4.  Test SCSI-II tagged queueing (I have no devices which support 
  62  *      tagged queueing)
  63  *
  64  * 5.  Test linked command handling code after Eric is ready with 
  65  *      the high level code.
  66  */
  67 
  68 #ifndef notyet
  69 #undef LINKED
  70 #undef USLEEP
  71 #undef REAL_DMA
  72 #endif
  73 
  74 #ifdef REAL_DMA_POLL
  75 #undef READ_OVERRUNS
  76 #define READ_OVERRUNS
  77 #endif
  78 
  79 /*
  80  * Design
  81  * Issues :
  82  *
  83  * The other Linux SCSI drivers were written when Linux was Intel PC-only,
  84  * and specifically for each board rather than each chip.  This makes their
  85  * adaptation to platforms like the Mac (Some of which use NCR5380's)
  86  * more difficult than it has to be.
  87  *
  88  * Also, many of the SCSI drivers were written before the command queing
  89  * routines were implemented, meaning their implementations of queued 
  90  * commands were hacked on rather than designed in from the start.
  91  *
  92  * When I designed the Linux SCSI drivers I figured that 
  93  * while having two different SCSI boards in a system might be useful
  94  * for debugging things, two of the same type wouldn't be used.
  95  * Well, I was wrong and a number of users have mailed me about running
  96  * multiple high-performance SCSI boards in a server.
  97  *
  98  * Finally, when I get questions from users, I have no idea what 
  99  * revision of my driver they are running.
 100  *
 101  * This driver attempts to address these problems :
 102  * This is a generic 5380 driver.  To use it on a different platform, 
 103  * one simply writes appropriate system specific macros (ie, data
 104  * transfer - some PC's will use the I/O bus, 68K's must use 
 105  * memory mapped) and drops this file in their 'C' wrapper.
 106  *
 107  * As far as command queueing, two queues are maintained for 
 108  * each 5380 in the system - commands that haven't been issued yet,
 109  * and commands that are currently executing.  This means that an 
 110  * unlimited number of commands may be queued, letting 
 111  * more commands propogate from the higher driver levels giving higher 
 112  * througput.  Note that both I_T_L and I_T_L_Q nexuses are supported, 
 113  * allowing multiple commands to propogate all the way to a SCSI-II device 
 114  * while a command is allready executing.
 115  *
 116  * To solve the multiple-boards-in-the-same-system problem, 
 117  * there is a separate instance structure for each instance
 118  * of a 5380 in the system.  So, mutliple NCR5380 drivers will
 119  * be able to coexist with appropriate changes to the high level
 120  * SCSI code.  
 121  *
 122  * A NCR5380_PUBLIC_REVISION macro is provided, with the release
 123  * number (updated for each public release) printed by the 
 124  * NCR5380_print_options command, which should be called from the 
 125  * wrapper detect function, so that I know what release of the driver
 126  * users are using.
 127  *
 128  * Issues specific to the NCR5380 : 
 129  *
 130  * When used in a PIO or pseudo-dma mode, the NCR5380 is a braindead 
 131  * piece of hardware that requires you to sit in a loop polling for 
 132  * the REQ signal as long as you are connected.  Some devices are 
 133  * brain dead (ie, many TEXEL CD ROM drives) and won't disconnect 
 134  * while doing long seek operations.
 135  * 
 136  * The workarround for this is to keep track of devices that have
 137  * disconnected.  If the device hasn't disconnected, for commands that
 138  * should disconnect, we do something like 
 139  *
 140  * while (!REQ is asserted) { sleep for N usecs; poll for M usecs }
 141  * 
 142  * Some tweaking of N and M needs to be done.  An algorithm based 
 143  * on "time to data" would give the best results as long as short time
 144  * to datas (ie, on the same track) were considered, however these 
 145  * broken devices are the exception rather than the rule and I'd rather
 146  * spend my time optomizing for the normal case.
 147  *
 148  * Architecture :
 149  *
 150  * At the heart of the design is a corroutine, NCR5380_main,
 151  * which is started when not running by the interrupt handler,
 152  * timer, and queue command function.  It attempts to establish
 153  * I_T_L or I_T_L_Q nexuses by removing the commands from the 
 154  * issue queue and calling NCR5380_select() if a nexus 
 155  * is not established. 
 156  *
 157  * Once a nexus is established, the NCR5380_information_transfer()
 158  * phase goes through the various phases as instructed by the target.
 159  * if the target goes into MSG IN and sends a DISCONNECT message,
 160  * the command structure is placed into the per instance disconnected
 161  * queue, and NCR5380_main tries to find more work.  If USLEEP
 162  * was defined, and the target is idle for too long, the system
 163  * will try to sleep.
 164  *
 165  * If a command has disconnected, eventually an interrupt will trigger,
 166  * calling NCR5380_intr()  which will inturn call NCR5380_reselect
 167  * to restablish a nexus.  This will run main if necessary.
 168  *
 169  * On command termination, the done function will be called as 
 170  * appropriate.
 171  *
 172  * SCSI pointers are maintained in the SCp field of SCSI command 
 173  * structures, being initialized after the command is connected
 174  * in NCR5380_select, and set as appropriate in NCR5380_information_transfer.
 175  * Note that in violation of the standard, an implicit SAVE POINTERS operation
 176  * is done, since some BROKEN disks fail to issue an explicit SAVE POINTERS.
 177  */
 178 
 179 /*
 180  * Using this file :
 181  * This file a skeleton Linux SCSI driver for the NCR 5380 series
 182  * of chips.  To use it, you write a architecture specific functions 
 183  * and macros and include this file in your driver.
 184  *
 185  * These macros control options : 
 186  * AUTOPROBE_IRQ - if defined, the NCR5380_probe_irq() function will be 
 187  *      defined.
 188  * 
 189  * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
 190  *      for commands that return with a CHECK CONDITION status. 
 191  *
 192  * DIFFERENTIAL - if defined, NCR53c81 chips will use external differential
 193  *      tracievers. 
 194  *
 195  * LINKED - if defined, linked commands are supported.
 196  *
 197  * PSEUDO_DMA - if defined, PSEUDO DMA is used during the data transfer phases.
 198  *
 199  * REAL_DMA - if defined, REAL DMA is used during the data transfer phases.
 200  *
 201  * REAL_DMA_POLL - if defined, REAL DMA is used but the driver doesn't
 202  *      rely on phase mismatch and EOP interrupts to determine end 
 203  *      of phase.
 204  *
 205  * SCSI2 - if defined, SCSI-2 tagged queing is used where possible
 206  *
 207  * UNSAFE - leave interrupts enabled during pseudo-DMA transfers.  You
 208  *          only really want to use this if you're having a problem with
 209  *          dropped characters during high speed communications, and even
 210  *          then, you're going to be better off twiddling with transfersize
 211  *          in the high level code.
 212  *
 213  * USLEEP - if defined, on devices that aren't disconnecting from the 
 214  *      bus, we will go to sleep so that the CPU can get real work done 
 215  *      when we run a command that won't complete immediately.
 216  *
 217  * Note that if USLEEP is defined, NCR5380_TIMER *must* also be
 218  * defined.
 219  *
 220  * Defaults for these will be provided if USLEEP is defined, although
 221  * the user may want to adjust these to allocate CPU resources to 
 222  * the SCSI driver or "real" code.
 223  * 
 224  * USLEEP_SLEEP - amount of time, in jiffies, to sleep
 225  *
 226  * USLEEP_POLL - amount of time, in jiffies, to poll
 227  *
 228  * These macros MUST be defined :
 229  * NCR5380_local_declare() - declare any local variables needed for your transfer
 230  *      routines.
 231  *
 232  * NCR5380_setup(instance) - initialize any local variables needed from a given
 233  *      instance of the host adapter for NCR5380_{read,write,pread,pwrite}
 234  * 
 235  * NCR5380_read(register)  - read from the specified register
 236  *
 237  * NCR5380_write(register, value) - write to the specific register 
 238  *
 239  * NCR5380_implementation_fields  - additional fields needed for this 
 240  *      specific implementation of the NCR5380
 241  *
 242  * Either real DMA *or* pseudo DMA may be implemented
 243  * REAL functions : 
 244  * NCR5380_REAL_DMA should be defined if real DMA is to be used.
 245  * Note that the DMA setup functions should return the number of bytes 
 246  *      that they were able to program the controller for.
 247  *
 248  * Also note that generic i386/PC versions of these macros are 
 249  *      available as NCR5380_i386_dma_write_setup,
 250  *      NCR5380_i386_dma_read_setup, and NCR5380_i386_dma_residual.
 251  *
 252  * NCR5380_dma_write_setup(instance, src, count) - initialize
 253  * NCR5380_dma_read_setup(instance, dst, count) - initialize
 254  * NCR5380_dma_residual(instance); - residual count
 255  *
 256  * PSEUDO functions :
 257  * NCR5380_pwrite(instance, src, count)
 258  * NCR5380_pread(instance, dst, count);
 259  *
 260  * If nothing specific to this implementation needs doing (ie, with external
 261  * hardware), you must also define 
 262  *  
 263  * NCR5380_queue_command
 264  * NCR5380_reset
 265  * NCR5380_abort
 266  *
 267  * to be the global entry points into the specific driver, ie 
 268  * #define NCR5380_queue_command t128_queue_command.
 269  *
 270  * If this is not done, the routines will be defined as static functions
 271  * with the NCR5380* names and the user must provide a globally
 272  * accessable wrapper function.
 273  *
 274  * The generic driver is initialized by calling NCR5380_init(instance),
 275  * after setting the appropriate host specific fields and ID.  If the 
 276  * driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance,
 277  * possible) function may be used.  Before the specific driver initialization
 278  * code finishes, NCR5380_print_options should be called.
 279  */
 280 
 281 static struct Scsi_Host *first_instance = NULL;
 282 static Scsi_Host_Template *the_template = NULL;
 283 
 284 /*
 285  * Function : void initialize_SCp(Scsi_Cmnd *cmd)
 286  *
 287  * Purpose : initialize the saved data pointers for cmd to point to the 
 288  *      start of the buffer.
 289  *
 290  * Inputs : cmd - Scsi_Cmnd structure to have pointers reset.
 291  */
 292 
 293 static __inline__ void initialize_SCp(Scsi_Cmnd *cmd) {
     /* [previous][next][first][last][top][bottom][index][help] */
 294     /* 
 295      * Initialize the Scsi Pointer field so that all of the commands in the 
 296      * various queues are valid.
 297      */
 298 
 299     if (cmd->use_sg) {
 300         cmd->SCp.buffer = (struct scatterlist *) cmd->buffer;
 301         cmd->SCp.buffers_residual = cmd->use_sg - 1;
 302         cmd->SCp.ptr = (char *) cmd->SCp.buffer->address;
 303         cmd->SCp.this_residual = cmd->SCp.buffer->length;
 304     } else {
 305         cmd->SCp.buffer = NULL;
 306         cmd->SCp.buffers_residual = 0;
 307         cmd->SCp.ptr = (char *) cmd->request_buffer;
 308         cmd->SCp.this_residual = cmd->request_bufflen;
 309     }
 310 }
 311 
 312 #include <linux/delay.h>
 313 
 314 #ifdef NDEBUG
 315 static struct {
 316     unsigned char mask;
 317     char * name;} 
 318 signals[] = {{ SR_DBP, "PARITY"}, { SR_RST, "RST" }, { SR_BSY, "BSY" }, 
 319     { SR_REQ, "REQ" }, { SR_MSG, "MSG" }, { SR_CD,  "CD" }, { SR_IO, "IO" }, 
 320     { SR_SEL, "SEL" }, {0, NULL}}, 
 321 basrs[] = {{BASR_ATN, "ATN"}, {BASR_ACK, "ACK"}, {0, NULL}},
 322 icrs[] = {{ICR_ASSERT_RST, "ASSERT RST"},{ICR_ASSERT_ACK, "ASSERT ACK"},
 323     {ICR_ASSERT_BSY, "ASSERT BSY"}, {ICR_ASSERT_SEL, "ASSERT SEL"}, 
 324     {ICR_ASSERT_ATN, "ASSERT ATN"}, {ICR_ASSERT_DATA, "ASSERT DATA"}, 
 325     {0, NULL}},
 326 mrs[] = {{MR_BLOCK_DMA_MODE, "MODE BLOCK DMA"}, {MR_TARGET, "MODE TARGET"}, 
 327     {MR_ENABLE_PAR_CHECK, "MODE PARITY CHECK"}, {MR_ENABLE_PAR_INTR, 
 328     "MODE PARITY INTR"}, {MR_MONITOR_BSY, "MODE MONITOR BSY"},
 329     {MR_DMA_MODE, "MODE DMA"}, {MR_ARBITRATE, "MODE ARBITRATION"}, 
 330     {0, NULL}};
 331 
 332 /*
 333  * Function : void NCR5380_print(struct Scsi_Host *instance)
 334  *
 335  * Purpose : print the SCSI bus signals for debugging purposes
 336  *
 337  * Input : instance - which NCR5380
 338  */
 339 
 340 static void NCR5380_print(struct Scsi_Host *instance) {
     /* [previous][next][first][last][top][bottom][index][help] */
 341     NCR5380_local_declare();
 342     unsigned char status, data, basr, mr, icr, i;
 343     NCR5380_setup(instance);
 344     cli();
 345     data = NCR5380_read(CURRENT_SCSI_DATA_REG);
 346     status = NCR5380_read(STATUS_REG);
 347     mr = NCR5380_read(MODE_REG);
 348     icr = NCR5380_read(INITIATOR_COMMAND_REG);
 349     basr = NCR5380_read(BUS_AND_STATUS_REG);
 350     sti();
 351     for (i = 0; signals[i].mask ; ++i) 
 352         if (status & signals[i].mask)
 353             printk(" %s", signals[i].name);
 354     for (i = 0; basrs[i].mask ; ++i) 
 355         if (basr & basrs[i].mask)
 356             printk(" %s", basrs[i].name);
 357     for (i = 0; icrs[i].mask; ++i) 
 358         if (icr & icrs[i].mask)
 359             printk(" %s", icrs[i].name);
 360     for (i = 0; mrs[i].mask; ++i) 
 361         if (mr & mrs[i].mask)
 362             printk(" %s", mrs[i].name);
 363     printk("\n");
 364 }
 365 
 366 static struct {
 367     unsigned char value;
 368     char *name;
 369 } phases[] = {
 370 {PHASE_DATAOUT, "DATAOUT"}, {PHASE_DATAIN, "DATAIN"}, {PHASE_CMDOUT, "CMDOUT"},
 371 {PHASE_STATIN, "STATIN"}, {PHASE_MSGOUT, "MSGOUT"}, {PHASE_MSGIN, "MSGIN"},
 372 {PHASE_UNKNOWN, "UNKNOWN"}};
 373 
 374 /* 
 375  * Function : void NCR5380_print_phase(struct Scsi_Host *instance)
 376  *
 377  * Purpose : print the current SCSI phase for debugging purposes
 378  *
 379  * Input : instance - which NCR5380
 380  */
 381 
 382 static void NCR5380_print_phase(struct Scsi_Host *instance) {
     /* [previous][next][first][last][top][bottom][index][help] */
 383     NCR5380_local_declare();
 384     unsigned char status;
 385     int i;
 386     NCR5380_setup(instance);
 387 
 388     status = NCR5380_read(STATUS_REG);
 389     if (!(status & SR_REQ)) 
 390         printk("scsi%d : REQ not asserted, phase unknown.\n", 
 391             instance->host_no);
 392     else {
 393         for (i = 0; (phases[i].value != PHASE_UNKNOWN) && 
 394             (phases[i].value != (status & PHASE_MASK)); ++i); 
 395         printk("scsi%d : phase %s\n", instance->host_no, phases[i].name);
 396     }
 397 }
 398 #endif
 399 
 400 /*
 401  * We need to have our corroutine active given these constraints : 
 402  * 1.  The mutex flag, main_running, can only be set when the main 
 403  *     routine can actually process data, otherwise SCSI commands
 404  *     will never get issued.
 405  *
 406  * 2.  NCR5380_main() shouldn't be called before it has exited, because
 407  *     other drivers have had kernel stack overflows in similar
 408  *     situations.
 409  *
 410  * 3.  We don't want to inline NCR5380_main() because of space concerns,
 411  *     even though it is only called in two places.
 412  *
 413  * So, the solution is to set the mutex in an inline wrapper for the 
 414  * main corroutine, and have the main corroutine exit with interrupts 
 415  * disabled after the final search through the queues so that no race 
 416  * conditions are possible.
 417  */
 418 
 419 static volatile int main_running = 0;
 420 
 421 /* 
 422  * Function : run_main(void)
 423  * 
 424  * Purpose : insure that the coroutine is running and will process our 
 425  *      request.  main_running is checked/set here (in an inline function)
 426  *      rather than in NCR5380_main itself to reduce the chances of stack
 427  *      overflow.
 428  *
 429  */
 430 
 431 static __inline__ void run_main(void) {
     /* [previous][next][first][last][top][bottom][index][help] */
 432     cli();
 433     if (!main_running) {
 434         main_running = 1;
 435         NCR5380_main();
 436         /* 
 437          * main_running is cleared in NCR5380_main once it can't do 
 438          * more work, and NCR5380_main exits with interrupts disabled.
 439          */
 440         sti();
 441     } else 
 442         sti();
 443 }
 444 
 445 #ifdef USLEEP
 446 #ifndef NCR5380_TIMER
 447 #error "NCR5380_TIMER must be defined so that this type of NCR5380 driver gets a unique timer."
 448 #endif
 449 
 450 /*
 451  * These need tweaking, and would probably work best as per-device 
 452  * flags initialized differently for disk, tape, cd, etc devices.
 453  * People with broken devices are free to experiment as to what gives
 454  * the best results for them.
 455  *
 456  * USLEEP_SLEEP should be a minimum seek time.
 457  *
 458  * USLEEP_POLL should be a maximum rotational latency.
 459  */
 460 #ifndef USLEEP_SLEEP
 461 /* 20 ms (reasonable hard disk speed) */
 462 #define USLEEP_SLEEP 2
 463 #endif
 464 /* 300 RPM (floppy speed) */
 465 #ifndef USLEEP_POLL
 466 #define USLEEP_POLL 20
 467 #endif
 468 
 469 static struct Scsi_Host * expires_first = NULL;
 470 
 471 /* 
 472  * Function : int should_disconnect (unsigned char cmd)
 473  *
 474  * Purpose : decide weather a commmand would normally disconnect or 
 475  *      not, since if it won't disconnect we should go to sleep.
 476  *
 477  * Input : cmd - opcode of SCSI command
 478  *
 479  * Returns : DISCONNECT_LONG if we should disconnect for a really long 
 480  *      time (ie always, sleep, look for REQ active, sleep), 
 481  *      DISCONNECT_TIME_TO_DATA if we would only disconnect for a normal
 482  *      time-to-data dealy, DISCONNECT_NONE if this command would return
 483  *      immediately.
 484  *
 485  *      Future sleep algorithms based on time to data can exploit 
 486  *      something like this so they can differentiate between "normal" 
 487  *      (ie, read, write, seek) and unusual commands (ie, * format).
 488  *
 489  * Note : We don't deal with commands that handle an immediate disconnect,
 490  *        
 491  */
 492 
 493 static int should_disconnect (unsigned char cmd) {
     /* [previous][next][first][last][top][bottom][index][help] */
 494     switch (cmd) {
 495     case READ_6:
 496     case WRITE_6:
 497     case SEEK_6:
 498     case READ_10:
 499     case WRITE_10:
 500     case SEEK_10:
 501         return DISCONNECT_TIME_TO_DATA;
 502     case FORMAT_UNIT:
 503     case SEARCH_HIGH:
 504     case SEARCH_LOW:
 505     case SEARCH_EQUAL:
 506         return DISCONNECT_LONG;
 507     default:
 508         return DISCONNECT_NONE;
 509     }
 510 }
 511 
 512 /*
 513  * Assumes instance->time_expires has been set in higher level code.
 514  */
 515 
 516 static int NCR5380_set_timer (struct Scsi_Host *instance) {
     /* [previous][next][first][last][top][bottom][index][help] */
 517     struct Scsi_Host *tmp, **prev;
 518     
 519     cli();
 520     if (((struct NCR5380_hostdata *) (instance->host_data))->next_timer) {
 521         sti();
 522         return -1;
 523     }
 524 
 525     for (prev = &expires_first, tmp = expires_first; tmp; 
 526         prev = &(((struct NCR5380_hostdata *) tmp->host_data)->next_timer), 
 527         tmp = ((struct NCR5380_hostdata *) tmp->host_data)->next_timer)
 528         if (instance->time_expires < tmp->time_expires) 
 529             break;
 530            
 531     instance->next_timer = tmp;
 532     *prev = instance;
 533     timer_table[NCR5380_TIMER].expires = expires_first->time_expires;
 534     timer_active |= 1 << NCR5380_TIMER;
 535     sti;
 536     return 0;
 537 }    
 538 
 539 /* Doing something about unwanted rentrancy here might be useful */
 540 void NCR5380_timer_fn(void) {
     /* [previous][next][first][last][top][bottom][index][help] */
 541     struct Scsi_Host *instance;
 542     cli();
 543     for (; expires_first && expires_first->time_expires >= jiffies; ) {
 544         instance = ((NCR5380_hostdata *) expires_first->host_data)->
 545             expires_next;
 546         ((NCR5380_hostdata *) expires_first->host_data)->expires_next = 
 547             NULL;
 548         ((NCR5380_hostdata *) expires_first->host_data)->time_expires = 
 549             0;
 550         expires_first = instance;
 551     }
 552 
 553     if (expires_first) {
 554         timer_table[NCR5380_TIMER].expires = ((NCR5380_hostdata *) 
 555             expires_first->host_data)->time_expires;
 556         timer_active |= (1 << NCR5380_TIMER);
 557     } else {
 558         timer_table[NCR5380_TIMER].expires = 0;
 559         timer_active &= ~(1 << MCR5380_TIMER);
 560     }
 561     sti();
 562 
 563     run_main();
 564 }
 565 #endif /* def USLEEP */
 566 
 567 static void NCR5380_all_init (void) {
     /* [previous][next][first][last][top][bottom][index][help] */
 568     static int done = 0;
 569     if (!done) {
 570 #if (NDEBUG & NDEBUG_INIT)
 571         printk("scsi : NCR5380_all_init()\n");
 572 #endif
 573         done = 1;
 574 #ifdef USLEEP
 575         timer_table[NCR5380_TIMER].expires = 0;
 576         timer_table[NCR5380_TIMER].fn = NCR5380_timer_fn;
 577 #endif
 578     }
 579 }
 580 
 581 #ifdef AUTOPROBE_IRQ
 582 /*
 583  * Function : int NCR5380_probe_irq (struct Scsi_Host *instance, int possible)
 584  * 
 585  * Purpose : autoprobe for the IRQ line used by the NCR5380.  
 586  *
 587  * Inputs : instance - pointer to this instance of the NCR5380 driver,
 588  *          possible - bitmask of permissable interrupts.
 589  *
 590  * Returns : number of the IRQ selected, IRQ_NONE if no interrupt fired.
 591  * 
 592  * XXX no effort is made to deal with spurious interrupts. 
 593  */
 594 
 595 
 596 static int probe_irq;
 597 static void probe_intr (int sig) {
     /* [previous][next][first][last][top][bottom][index][help] */
 598     probe_irq = sig;
 599 };
 600 static struct sigaction probe_sigaction = { probe_intr, 0, SA_INTERRUPT,
 601     NULL};
 602 
 603 static int NCR5380_probe_irq (struct Scsi_Host *instance, int possible) {
     /* [previous][next][first][last][top][bottom][index][help] */
 604     NCR5380_local_declare();
 605     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *)
 606          instance->hostdata;
 607     unsigned long timeout;
 608     int trying_irqs, i, mask;
 609     NCR5380_setup(instance);
 610 
 611     for (trying_irqs = i = 0, mask = 1; i < 16; ++i, mask <<= 1) 
 612         if ((mask & possible) &&  (irqaction (i, &probe_sigaction) 
 613             == 0)) 
 614             trying_irqs |= mask;
 615 
 616     timeout = jiffies + 25;
 617     probe_irq = IRQ_NONE;
 618 
 619 /*
 620  * A interrupt is triggered whenever BSY = false, SEL = true
 621  * and a bit set in the SELECT_ENABLE_REG is asserted on the 
 622  * SCSI bus.
 623  *
 624  * Note that the bus is only driven when the phase control signals
 625  * (I/O, C/D, and MSG) match those in the TCR, so we must reset that
 626  * to zero.
 627  */
 628 
 629     NCR5380_write(TARGET_COMMAND_REG, 0);
 630     NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
 631     NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
 632     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | 
 633         ICR_ASSERT_SEL);
 634 
 635     while (probe_irq == IRQ_NONE && jiffies < timeout);
 636 
 637     NCR5380_write(SELECT_ENABLE_REG, 0);
 638     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 639 
 640     for (i = 0, mask = 1; i < 16; ++i, mask <<= 1)
 641         if (trying_irqs & mask) 
 642             free_irq(i);
 643 
 644     return probe_irq;
 645 }
 646 #endif /* AUTOPROBE_IRQ */
 647  
 648 /*
 649  * Function : void NCR58380_print_options (struct Scsi_Host *instance)
 650  *
 651  * Purpose : called by probe code indicating the NCR5380 driver
 652  *           options that were selected.
 653  *
 654  * Inputs : instance, pointer to this instance.  Unused.
 655  */
 656 
 657 static void NCR5380_print_options (struct Scsi_Host *instance) {
     /* [previous][next][first][last][top][bottom][index][help] */
 658     printk(" generic options"
 659 #ifdef AUTOPROBE_IRQ
 660     " AUTOPROBE_IRQ"
 661 #endif
 662 #ifdef AUTOSENSE 
 663     " AUTOSENSE"
 664 #endif
 665 #ifdef DIFFERENTIAL
 666     " DIFFERENTIAL"
 667 #endif
 668 #ifdef REAL_DMA
 669     " REAL DMA"
 670 #endif
 671 #ifdef REAL_DMA_POLL
 672     " REAL DMA POLL"
 673 #endif
 674 #ifdef PARITY
 675     " PARITY"
 676 #endif
 677 #ifdef PSEUDO_DMA
 678     " PSEUDO DMA"
 679 #endif
 680 #ifdef SCSI2
 681     " SCSI-2"
 682 #endif
 683 #ifdef UNSAFE
 684     " UNSAFE "
 685 #endif
 686     );
 687 #ifdef USLEEP
 688     printk(" USLEEP, USLEEP_POLL=%d USLEEP_SLEEP=%d", USLEEP_POLL, USLEEP_SLEEP);
 689 #endif
 690     printk(" generic release=%d", NCR5380_PUBLIC_RELEASE);
 691 }
 692 
 693 
 694 /* 
 695  * Function : void NCR5380_init (struct Scsi_Host *instance)
 696  *
 697  * Purpose : initializies *instance and corresponding 5380 chip.
 698  *
 699  * Inputs : instance - instantiation of the 5380 driver.  
 700  *
 701  * Notes : I assume that the host, hostno, and id bits have been
 702  *      set correctly.  I don't care about the irq and other fields. 
 703  * 
 704  */
 705 
 706 static void NCR5380_init (struct Scsi_Host *instance) {
     /* [previous][next][first][last][top][bottom][index][help] */
 707     NCR5380_local_declare();
 708     int i;
 709     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) 
 710         instance->hostdata;
 711     NCR5380_setup(instance);
 712 
 713     NCR5380_all_init();
 714 
 715     hostdata->id_mask = 1 << instance->this_id;
 716     for (i = hostdata->id_mask; i <= 0x80; i <<= 1)
 717         if (i > hostdata->id_mask)
 718             hostdata->id_higher_mask |= i;
 719     for (i = 0; i < 8; ++i)
 720         hostdata->busy[i] = 0;
 721 #ifdef REAL_DMA
 722     hostdata->dmalen = 0;
 723 #endif
 724     hostdata->connected = NULL;
 725     hostdata->issue_queue = NULL;
 726     hostdata->disconnected_queue = NULL;
 727     hostdata->flags = FLAG_CHECK_LAST_BYTE_SENT;
 728 
 729     if (!the_template) {
 730         the_template = instance->hostt;
 731         first_instance = instance;
 732     }
 733         
 734 
 735 #ifdef USLEEP
 736     hostdata->time_expires = 0;
 737     hostdata->next_timer = NULL;
 738 #endif
 739 
 740 #ifndef AUTOSENSE
 741     if ((instance->cmd_per_lun > 1) || instance->can_queue > 1)) 
 742          printk("scsi%d : WARNING : support for multiple outstanding commands enabled\n"
 743                 "         without AUTOSENSE option, contigent alligence conditions may\n"
 744                 "         be incorrectly cleared.\n", instance->host_no);
 745 #endif /* def AUTOSENSE */
 746 
 747     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 748     NCR5380_write(MODE_REG, MR_BASE);
 749     NCR5380_write(TARGET_COMMAND_REG, 0);
 750     NCR5380_write(SELECT_ENABLE_REG, 0);
 751 }
 752 
 753 /* 
 754  * Function : int NCR5380_queue_command (Scsi_Cmnd *cmd, 
 755  *      void (*done)(Scsi_Cmnd *)) 
 756  *
 757  * Purpose :  enqueues a SCSI command
 758  *
 759  * Inputs : cmd - SCSI command, done - function called on completion, with
 760  *      a pointer to the command descriptor.
 761  * 
 762  * Returns : 0
 763  *
 764  * Side effects : 
 765  *      cmd is added to the per instance issue_queue, with minor 
 766  *      twiddling done to the host specific fields of cmd.  If the 
 767  *      main coroutine is not running, it is restarted.
 768  *
 769  */
 770 
 771 /* Only make static if a wrapper function is used */
 772 #ifndef NCR5380_queue_command
 773 static
 774 #endif
 775 int NCR5380_queue_command (Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *)) {
     /* [previous][next][first][last][top][bottom][index][help] */
 776     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *)
 777         cmd->host->hostdata;
 778     Scsi_Cmnd *tmp;
 779 
 780 #if (NDEBUG & NDEBUG_NO_WRITE)
 781     switch (cmd->cmnd[0]) {
 782     case WRITE:
 783     case WRITE_10:
 784         printk("scsi%d : WRITE attempted with NO_WRITE debugging flag set\n",
 785             instance->host_no);
 786         cmd->result = (DID_ERROR << 16);
 787         done(cmd);
 788         return 0;
 789     }
 790 #endif /* (NDEBUG & NDEBUG_NO_WRITE) */
 791 
 792 
 793     /* 
 794      * We use the host_scribble field as a pointer to the next command  
 795      * in a queue 
 796      */
 797 
 798     cmd->host_scribble = NULL;
 799     cmd->scsi_done = done;
 800 
 801     cmd->result = 0;
 802 
 803 
 804     /* 
 805      * Insert the cmd into the issue queue. Note that REQUEST SENSE 
 806      * commands are added to the head of the queue since any command will
 807      * clear the contingent allegience condition that exists and the 
 808      * sense data is only guranteed to be valid while the condition exists.
 809      */
 810 
 811     cli();
 812     if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
 813         cmd->host_scribble = (unsigned char *) hostdata->issue_queue;
 814         hostdata->issue_queue = cmd;
 815     } else {
 816         for (tmp = (Scsi_Cmnd *) hostdata->issue_queue; tmp->host_scribble; 
 817                 tmp = (Scsi_Cmnd *) tmp->host_scribble);
 818         tmp->host_scribble = (unsigned char *) cmd;
 819     }
 820 #if (NDEBUG & NDEBUG_QUEUES)
 821     printk("scsi%d : command added to %s of queue\n", instance->host_no,
 822         (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail");
 823 #endif
 824 
 825 /* Run the coroutine if it isn't allready running. */
 826     run_main();
 827     return 0;
 828 }
 829 
 830 /*
 831  * Function : NCR5380_main (void) 
 832  *
 833  * Purpose : NCR5380_main is a corroutine that runs as long as more work can 
 834  *      be done on the NCR5380 host adapters in a system.  Both 
 835  *      NCR5380_queue_command() and NCR5380_intr() will try to start it 
 836  *      in case it is not running.
 837  * 
 838  * NOTE : NCR5380_main exits with interrupts *disabled*, the caller should 
 839  *  reenable them.  This prevents rentrancy and kernel stack overflow.
 840  */     
 841     
 842 static void NCR5380_main (void) {
     /* [previous][next][first][last][top][bottom][index][help] */
 843     Scsi_Cmnd *tmp, *prev;
 844     struct Scsi_Host *instance;
 845     struct NCR5380_hostdata *hostdata;
 846     int done;
 847 
 848     /*
 849      * We run (with interrupts disabled) until we're sure that none of 
 850      * the host adapters have anything that can be done, at which point 
 851      * we set main_running to 0 and exit.
 852      *
 853      * Interrupts are enabled before doing various other internal 
 854      * instructions, after we've decided that we need to run through
 855      * the loop again.
 856      *
 857      * this should prevent any race conditions.
 858      */
 859 
 860     do {
 861         cli(); /* Freeze request queues */
 862         done = 1;
 863         for (instance = first_instance; instance && instance->hostt == the_template; 
 864             instance=instance->next) {
 865             hostdata = (struct NCR5380_hostdata *) instance->hostdata;
 866             cli();
 867             if (!hostdata->connected) {
 868 #if (NDEBUG & NDEBUG_MAIN)
 869                 printk("scsi%d : not connected\n", instance->host_no);
 870 #endif
 871                 /*
 872                  * Search through the issue_queue for a command destined
 873                  * for a target that's not busy.
 874                  */
 875                 for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, 
 876                     prev = NULL; tmp; prev = tmp, tmp = (Scsi_Cmnd *) 
 877                     tmp->host_scribble) 
 878 
 879                     /*  When we find one, remove it from the issue queue. */
 880                     if (!(hostdata->busy[tmp->target] & (1 << tmp->lun))) {
 881                             if (prev)
 882                                 prev->host_scribble = tmp->host_scribble;
 883                             else
 884                                 hostdata->issue_queue = (Scsi_Cmnd *) tmp->host_scribble;
 885                         tmp->host_scribble = NULL;
 886 
 887                         /* renable interrupts after finding one */
 888                         sti();
 889 
 890                         /* 
 891                          * Attempt to establish an I_T_L nexus here. 
 892                          * On success, instance->hostdata->connected is set.
 893                          * On failure, we must add the command back to the
 894                          *   issue queue so we can keep trying. 
 895                          */
 896 #if (NDEBUG & (NDEBUG_MAIN | NDEBUG_QUEUES))
 897                         printk("scsi%d : main() : command for target %d lun %d removed from issue_queue\n",
 898                             instance->host_no, tmp->target, tmp->lun);
 899 #endif
 900                         /* 
 901                          * REQUEST SENSE commands are issued without tagged
 902                          * queueing, even on SCSI-II devices because the 
 903                          * contingent alligence condition exists for the 
 904                          * entire unit.
 905                          */
 906                         
 907                         if (!NCR5380_select(instance, tmp, 
 908                             (tmp->cmnd[0] == REQUEST_SENSE) ? TAG_NONE : 
 909                             TAG_NEXT)) {
 910                             break;
 911                         } else {
 912                             cli();
 913                             tmp->host_scribble = (unsigned char *) 
 914                                 hostdata->issue_queue;
 915                             hostdata->issue_queue = tmp;
 916                             sti();
 917 #if (NDEBUG & (NDEBUG_MAIN | NDEBUG_QUEUES))
 918                         printk("scsi%d : main(): select() failed, returned to issue_queue\n",
 919                             instance->host_no);
 920 #endif
 921                         }
 922                     } /* if target/lun is not busy */
 923             } /* if (!hostdata->connected) */
 924                 
 925             if (hostdata->connected 
 926 #ifdef REAL_DMA
 927                 && !hostdata->dmalen
 928 #endif
 929 #ifdef USLEEP
 930                 && (!hostdata->time_expires || hostdata->time_expires >= jiffies)
 931 #endif
 932                 ) {
 933                 sti();
 934 #if (NDEBUG & NDEBUG_MAIN)
 935                 printk("scsi%d : main() : performing information transfer\n",
 936                         instance->host_no);
 937 #endif
 938                 NCR5380_information_transfer(instance);
 939 #if (NDEBUG & NDEBUG_MAIN)
 940                 printk("scsi%d : main() : done set false\n", instance->host_no);
 941 #endif
 942                 done = 0;
 943             } else 
 944                 break;
 945         } /* for instance */
 946     } while (!done);
 947     main_running = 0;
 948 }
 949 
 950 /*
 951  * Function : void NCR5380_intr (int irq)
 952  * 
 953  * Purpose : handle interrupts, restablishing I_T_L or I_T_L_Q nexuses
 954  *      from the disconnected queue, and restarting NCR5380_main() 
 955  *      as required.
 956  *
 957  * Inputs : int irq, irq that caused this interrupt.
 958  *
 959  */
 960 
 961 static void NCR5380_intr (int irq) {
     /* [previous][next][first][last][top][bottom][index][help] */
 962     NCR5380_local_declare(); 
 963     struct Scsi_Host *instance;
 964     int done;
 965     unsigned char basr;
 966 #if (NDEBUG & NDEBUG_INTR)
 967     printk("scsi : NCR5380 irq %d triggered\n", irq);
 968 #endif
 969     do {
 970         done = 1;
 971         for (instance = first_instance; instance && (instance->hostt == 
 972             the_template); instance = instance->next)
 973             if (instance->irq == irq) {
 974                 
 975                 /* Look for pending interrupts */
 976                 NCR5380_setup(instance);
 977                 basr = NCR5380_read(BUS_AND_STATUS_REG);
 978                 /* XXX dispatch to appropriate routine if found and done=0 */
 979                 if (basr & BASR_IRQ) {
 980 #if (NDEBUG & NDEBUG_INTR)
 981                     NCR5380_print(instance);
 982 #endif
 983                     if ((NCR5380_read(STATUS_REG) & (SR_SEL | SR_IO)) == 
 984                         (SR_SEL | SR_IO)) {
 985                         done = 0;
 986                         sti();
 987 #if (NDEBUG & NDEBUG_INTR)
 988                         printk("scsi%d : SEL interrupt\n", instance->host_no);
 989 #endif
 990                         NCR5380_reselect(instance);
 991                         (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
 992                     } else if (basr & 
 993                         BASR_PARITY_ERROR) {
 994 #if (NDEBUG & NDEBUG_INTR)
 995                         printk("scsi%d : PARITY interrupt\n", instance->host_no);
 996 #endif
 997                         (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
 998                     } else {
 999 /*  
1000  * XXX the rest of the interrupt conditions should *only* occur during a 
1001  * DMA transfer, which I haven't gotten arround to fixing yet.
1002  */
1003 
1004 #if defined(REAL_DMA)
1005                     /*
1006                      * We should only get PHASE MISMATCH and EOP interrupts
1007                      * if we have DMA enabled, so do a sanity check based on
1008                      * the current setting of the MODE register.
1009                      */
1010 
1011                         if ((NCR5380_read(MODE_REG) & MR_DMA) && ((basr & 
1012                             BASR_END_DMA_TRANSFER) || 
1013                             !(basr & BASR_PHASE_MATCH))) {
1014                             int transfered;
1015 
1016                             if (!hostdata->connected) 
1017                                 panic("scsi%d : recieved end of DMA interrupt with no connected cmd\n",
1018                                     instance->hostno);
1019 
1020                             transfered = (hostdata->dmalen - NCR5380_dma_residual(instance));
1021                             hostdata->connected->SCp.this_residual -= transferred;
1022                             hostdata->connected->SCp.ptr += transferred;
1023                             hostdata->dmalen = 0;
1024 
1025                             (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
1026 
1027                             while (NCR5380_read(BUS_AND_STATUS_REG) & 
1028                                 BASR_ACK));
1029 
1030                             NCR5380_write(MODE_REG, MR_BASE);
1031                             NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1032                         }
1033 #else
1034 #if (NDEBUG & NDEBUG_INTR)
1035                     printk("scsi : unknown interrupt, BASR 0x%X, MR 0x%X, SR 0x%x\n", basr, NCR5380_read(MODE_REG), NCR5380_read(STATUS_REG));
1036 #endif
1037                     (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
1038 #endif
1039                     } 
1040                 } /* if BASR_IRQ */
1041                 if (!done) 
1042                     run_main();
1043             } /* if (instance->irq == irq) */
1044     } while (!done);
1045 }
1046 
1047 /* 
1048  * Function : int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd, 
1049  *      int tag);
1050  *
1051  * Purpose : establishes I_T_L or I_T_L_Q nexus for new or existing command,
1052  *      including ARBITRATION, SELECTION, and initial message out for 
1053  *      IDENTIFY and queue messages. 
1054  *
1055  * Inputs : instance - instantiation of the 5380 driver on which this 
1056  *      target lives, cmd - SCSI command to execute, tag - set to TAG_NEXT for 
1057  *      new tag, TAG_NONE for untagged queueing, otherwise set to the tag for 
1058  *      the command that is presently connected.
1059  * 
1060  * Returns : -1 if selection could not execute for some reason,
1061  *      0 if selection succeeeded or failed because the target 
1062  *      did not respond.
1063  *
1064  * Side effects : 
1065  *      If bus busy, arbitration failed, etc, NCR5380_select() will exit 
1066  *              with registers as they should have been on entry - ie
1067  *              SELECT_ENABLE will be set appropriately, the NCR5380
1068  *              will cease to drive any SCSI bus signals.
1069  *
1070  *      If successful : I_T_L or I_T_L_Q nexus will be established, 
1071  *              instance->connected will be set to cmd.  
1072  *              SELECT interrupt will be disabled.
1073  *
1074  *      If failed (no target) : cmd->scsi_done() will be called, and the 
1075  *              cmd->result host byte set to DID_BAD_TARGET.
1076  */
1077 
1078 static int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd,
     /* [previous][next][first][last][top][bottom][index][help] */
1079     int tag) {
1080     NCR5380_local_declare();
1081     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata*) 
1082         instance->hostdata;
1083     unsigned char tmp[3], phase;
1084     unsigned char *data;
1085     int len;
1086     unsigned long timeout;
1087     NCR5380_setup(instance);
1088 
1089 #if defined (NDEBUG) && (NDEBUG & NDEBUG_ARBITRATION) 
1090     NCR5380_print(instance);
1091     printk("scsi%d : starting arbitration, id = %d\n", instance->host_no,
1092         instance->this_id);
1093 #endif
1094 
1095     /* 
1096      * Set the phase bits to 0, otherwise the NCR5380 won't drive the 
1097      * data bus during SELECTION.
1098      */
1099 
1100     NCR5380_write(TARGET_COMMAND_REG, 0);
1101 
1102     /* Start arbitration */ 
1103     NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
1104     NCR5380_write(MODE_REG, MR_ARBITRATE);
1105 
1106     /* Wait for arbitration logic to complete */
1107     while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS));
1108 
1109 #if (NDEBUG & NDEBUG_ARBITRATION) 
1110     printk("scsi%d : arbitration complete\n", instance->host_no);
1111 /* Avoid GCC 2.4.5 asm needs to many reloads error */
1112     __asm__("nop");
1113 #endif
1114 
1115     /* 
1116      * The arbitration delay is 2.2us, but this is a minimum and there is 
1117      * no maximum so we can safely sleep for ceil(2.2) usecs to accomodate
1118      * the integral nature of udelay().
1119      *
1120      */
1121 
1122     udelay(3);
1123 
1124     /* Check for lost arbitration */
1125     if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) ||
1126         (NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_higher_mask) ||
1127         (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST)) {
1128         NCR5380_write(MODE_REG, MR_BASE); 
1129 #if (NDEBUG & NDEBUG_ARBITRATION)
1130     printk("scsi%d : lost arbitration, deasserting MR_ARBITRATE\n", 
1131         instance->host_no);
1132 #endif
1133         return -1;
1134     }
1135 
1136     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_SEL);
1137     
1138     if (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) {
1139         NCR5380_write(MODE_REG, MR_BASE);
1140         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1141 #if (NDEBUG & NDEBUG_ARBITRATION)
1142     printk("scsi%d : lost arbitration, deasserting ICR_ASSERT_SEL\n", 
1143         instance->host_no);
1144 #endif
1145         return -1;
1146     }
1147 
1148     /* 
1149      * Again, bus clear + bus settle time is 1.2us, however, this is 
1150      * a minimum so we'll udelay ceil(1.2)
1151      */
1152 
1153     udelay(2);  
1154 
1155 #if (NDEBUG & NDEBUG_ARBITRATION)
1156     printk("scsi%d : won arbitration\n", instance->host_no);
1157 #endif
1158 
1159     /* 
1160      * Now that we have won arbitration, start Selection process, asserting 
1161      * the host and target ID's on the SCSI bus.
1162      */
1163 
1164     NCR5380_write(OUTPUT_DATA_REG, (hostdata->id_mask | (1 << cmd->target)));
1165 
1166     /* 
1167      * Raise ATN while SEL is true before BSY goes false from arbitration,
1168      * since this is the only way to gurantee that we'll get a MESSAGE OUT
1169      * phase immediately after selection.
1170      */
1171 
1172     NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_BSY | 
1173         ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_SEL ));
1174     NCR5380_write(MODE_REG, MR_BASE);
1175 
1176     /* 
1177      * Reselect interrupts must be turned off prior to the dropping of BSY,
1178      * otherwise we will trigger an interrupt.
1179      */
1180     NCR5380_write(SELECT_ENABLE_REG, 0);
1181 
1182     /* Reset BSY */
1183     NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_DATA | 
1184         ICR_ASSERT_ATN | ICR_ASSERT_SEL));
1185 
1186     /* 
1187      * Something wierd happens when we cease to drive BSY - looks
1188      * like the board/chip is letting us do another read before the 
1189      * appropriate propogation delay has expired, and we're confusing
1190      * a BSY signal from ourselves as the target's response to SELECTION.
1191      *
1192      * A small delay (the 'C++' frontend breaks the pipeline with an
1193      * unecessary jump, making it work on my 386-33/Trantor T128, the
1194      * tighter 'C' code breaks and requires this) solves the problem - 
1195      * the 1 us delay is arbitrary, and only used because this delay will 
1196      * be the same on other platforms and since it works here, it should 
1197      * work there.
1198      */
1199 
1200     udelay(1);
1201 
1202 #if (NDEBUG & NDEBUG_SELECTION)
1203     printk("scsi%d : selecting target %d\n", instance->host_no, cmd->target);
1204 #endif
1205 
1206     /* 
1207      * The SCSI specification calls for a 250 ms timeout for the actual 
1208      * selection.
1209      */
1210 
1211     timeout = jiffies + 25; 
1212 
1213     /* 
1214      * XXX very interesting - we're seeing a bounce where the BSY we 
1215      * asserted is being reflected / still asserted (propogation delay?)
1216      * and it's detecting as true.  Sigh.
1217      */
1218 
1219     while ((jiffies < timeout) && !(NCR5380_read(STATUS_REG) & SR_BSY));
1220 
1221     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
1222 
1223     if (!(NCR5380_read(STATUS_REG) & SR_BSY)) {
1224         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1225         cmd->result = DID_BAD_TARGET << 16;
1226         cmd->scsi_done(cmd);
1227         NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
1228 #if (NDEBUG & NDEBUG_SELECTION)
1229         printk("scsi%d : target did not respond within 250ms\n", 
1230             instance->host_no);
1231 #endif
1232         return 0;
1233     } 
1234 
1235     /*
1236      * Since we followed the SCSI spec, and raised ATN while SEL 
1237      * was true but before BSY was false during selection, the information
1238      * transfer phase should be a MESSAGE OUT phase so that we can send the
1239      * IDENTIFY message.
1240      * 
1241      * If SCSI-II tagged queing is enabled, we also send a SIMPLE_QUEUE_TAG
1242      * message (2 bytes) with a tag ID that we increment with every command
1243      * until it wraps back to 0.
1244      *
1245      * XXX - it turns out that there are some broken SCSI-II devices,
1246      *       which claim to support tagged queing but fail when more than
1247      *       some number of commands are issued at once.
1248      */
1249 
1250     /* Wait for start of REQ/ACK handshake */
1251     while (!(NCR5380_read(STATUS_REG) & SR_REQ));
1252 
1253 #if (NDEBUG & NDEBUG_SELECTION)
1254     printk("scsi%d : target %d selected, going into MESSAGE OUT phase.\n",
1255         instance->host_no, cmd->target);
1256 #endif
1257     tmp[0] = IDENTIFY(((instance->irq == IRQ_NONE) ? 0 : 1), cmd->lun);
1258 #ifdef SCSI2
1259     if (scsi_devices[cmd->index].tagged_queue && (tag != TAG_NONE)) {
1260         tmp[1] = SIMPLE_QUEUE_TAG;
1261         if (tag == TAG_NEXT) {
1262             /* 0 is TAG_NONE, used to imply no tag for this command */
1263             if (scsi_devices[cmd->index].current_tag == 0)
1264                 scsi_devices[cmd->index].current_tag = 1;
1265 
1266             cmd->tag = scsi_devices[cmd->index].current_tag;
1267             scsi_devices[cmd->index].current_tag++;
1268         } else  
1269             cmd->tag = (unsigned char) tag;
1270 
1271         tmp[2] = cmd->tag;
1272         hostdata->last_message = SIMPLE_QUEUE_TAG;
1273         len = 3;
1274     } else 
1275 #endif /* def SCSI2 */
1276     {
1277         len = 1;
1278         cmd->tag=0;
1279     }
1280 
1281     /* Send message(s) */
1282     data = tmp;
1283     phase = PHASE_MSGOUT;
1284     NCR5380_transfer_pio(instance, &phase, &len, &data);
1285 #if (NDEBUG & NDEBUG_SELECTION)
1286     printk("scsi%d : nexus established.\n", instance->host_no);
1287 #endif
1288     /* XXX need to handle errors here */
1289     hostdata->connected = cmd;
1290 #ifdef SCSI2
1291     if (!scsi_devices[cmd->index].tagged_queue)
1292 #endif    
1293         hostdata->busy[cmd->target] |= (1 << cmd->lun);
1294 
1295     initialize_SCp(cmd);
1296 
1297     return 0;
1298 }
1299 
1300 /* 
1301  * Function : int NCR5380_transfer_pio (struct Scsi_Host *instance, 
1302  *      unsigned char *phase, int *count, unsigned char **data)
1303  *
1304  * Purpose : transfers data in given phase using polled I/O
1305  *
1306  * Inputs : instance - instance of driver, *phase - pointer to 
1307  *      what phase is expected, *count - pointer to number of 
1308  *      bytes to transfer, **data - pointer to data pointer.
1309  * 
1310  * Returns : -1 when different phase is enterred without transfering
1311  *      maximum number of bytes, 0 if all bytes or transfered or exit
1312  *      is in same phase.
1313  *
1314  *      Also, *phase, *count, *data are modified in place.
1315  *
1316  * XXX Note : handling for bus free may be useful.
1317  */
1318 
1319 /*
1320  * Note : this code is not as quick as it could be, however it 
1321  * IS 100% reliable, and for the actual data transfer where speed
1322  * counts, we will always do a pseudo DMA or DMA transfer.
1323  */
1324 
1325 static int NCR5380_transfer_pio (struct Scsi_Host *instance, 
     /* [previous][next][first][last][top][bottom][index][help] */
1326         unsigned char *phase, int *count, unsigned char **data) {
1327     NCR5380_local_declare();
1328     register unsigned char p = *phase, tmp;
1329     register int c = *count;
1330     register unsigned char *d = *data;
1331     NCR5380_setup(instance);
1332 
1333     /* 
1334      * The NCR5380 chip will only drive the SCSI bus when the 
1335      * phase specified in the appropriate bits of the TARGET COMMAND
1336      * REGISTER match the STATUS REGISTER
1337      */
1338 
1339     NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));
1340 
1341     do {
1342         /* 
1343          * Wait for assertion of REQ, after which the phase bits will be 
1344          * valid 
1345          */
1346         while (!((tmp = NCR5380_read(STATUS_REG)) & SR_REQ));
1347 
1348 #if (NDEBUG & NDEBUG_HANDSHAKE)
1349         printk("scsi%d : REQ detected\n", instance->host_no);
1350 #endif
1351 
1352         /* Check for phase mismatch */  
1353         if ((tmp & PHASE_MASK) != p) {
1354 #if (NDEBUG & NDEBUG_PIO)
1355             printk("scsi%d : phase mismatch\n", instance->host_no);
1356             NCR5380_print_phase(instance);
1357 #endif
1358             break;
1359         }
1360 
1361         /* Do actual transfer from SCSI bus to / from memory */
1362         if (!(p & SR_IO)) 
1363             NCR5380_write(OUTPUT_DATA_REG, *d);
1364         else 
1365             *d = NCR5380_read(CURRENT_SCSI_DATA_REG);
1366 
1367         ++d;
1368 
1369         /* 
1370          * The SCSI standard suggests that in MSGOUT phase, the initiator
1371          * should drop ATN on the last byte of the message phase
1372          * after REQ has been asserted for the handshake but before
1373          * the initiator raises ACK.
1374          */
1375 
1376         if (!(p & SR_IO)) {
1377             if (!((p & SR_MSG) && c > 1)) {
1378                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | 
1379                     ICR_ASSERT_DATA);
1380 #if (NDEBUG & NDEBUG_PIO)
1381         NCR5380_print(instance);
1382 #endif
1383                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | 
1384                         ICR_ASSERT_DATA | ICR_ASSERT_ACK);
1385             } else {
1386                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
1387                     ICR_ASSERT_DATA | ICR_ASSERT_ATN);
1388 #if (NDEBUG & NDEBUG_PIO)
1389         NCR5380_print(instance);
1390 #endif
1391                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | 
1392                     ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
1393             }
1394         } else {
1395 #if (NDEBUG & NDEBUG_PIO)
1396         NCR5380_print(instance);
1397 #endif
1398         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ACK);
1399         }
1400 
1401         while (NCR5380_read(STATUS_REG) & SR_REQ);
1402 
1403 #if (NDEBUG & NDEBUG_HANDSHAKE)
1404             printk("scsi%d : req false, handshake complete\n", instance->host_no);
1405 #endif
1406 
1407         if (!(p == PHASE_MSGOUT && c > 1))
1408             NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1409         else
1410             NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
1411     } while (--c);
1412 
1413 #if (NDEBUG & NDEBUG_PIO) 
1414     printk("scsi%d : residual %d\n", instance->host_no, c);
1415 #endif
1416 
1417     *count = c;
1418     *data = d;
1419     tmp = NCR5380_read(STATUS_REG);
1420     if (tmp & SR_REQ)
1421         *phase = tmp & PHASE_MASK;
1422     else 
1423         *phase = PHASE_UNKNOWN;
1424 
1425     if (!c || (*phase == p))
1426         return 0;
1427     else 
1428         return -1;
1429 }
1430 
1431 #if defined(REAL_DMA) || defined(PSEUDO_DMA) || defined (REAL_DMA_POLL)
1432 /* 
1433  * Function : int NCR5380_transfer_dma (struct Scsi_Host *instance, 
1434  *      unsigned char *phase, int *count, unsigned char **data)
1435  *
1436  * Purpose : transfers data in given phase using either real
1437  *      or pseudo DMA.
1438  *
1439  * Inputs : instance - instance of driver, *phase - pointer to 
1440  *      what phase is expected, *count - pointer to number of 
1441  *      bytes to transfer, **data - pointer to data pointer.
1442  * 
1443  * Returns : -1 when different phase is enterred without transfering
1444  *      maximum number of bytes, 0 if all bytes or transfered or exit
1445  *      is in same phase.
1446  *
1447  *      Also, *phase, *count, *data are modified in place.
1448  *
1449  */
1450 
1451 
1452 static int NCR5380_transfer_dma (struct Scsi_Host *instance, 
     /* [previous][next][first][last][top][bottom][index][help] */
1453     unsigned char *phase, int *count, unsigned char **data) {
1454     NCR5380_local_declare();
1455     register int c = *count;
1456     register unsigned char p = *phase;
1457     register unsigned char *d = *data;
1458     unsigned char tmp;
1459     int foo;
1460 #if defined(REAL_DMA_POLL)
1461     int cnt, toPIO;
1462     unsigned char saved_data = 0, overrun = 0, residue;
1463 #endif
1464 
1465     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) 
1466         instance->hostdata;
1467 
1468     NCR5380_setup(instance);
1469 
1470     if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
1471         *phase = tmp;
1472         return -1;
1473     }
1474 #if defined(REAL_DMA) || defined(REAL_DMA_POLL) 
1475 #ifdef READ_OVERRUNS
1476      if (p & SR_IO) {
1477        c -= 2;
1478      }
1479 #endif
1480 #if (NDEBUG & NDEBUG_DMA)
1481     printk("scsi%d : initializing DMA channel %d for %s, %d bytes %s %0x\n",
1482         instance->host_no, instance->dma_channel, (p & SR_IO) ? "reading" :
1483         "writing", c, (p & SR_IO) ? "to" : "from", (unsigned) d);
1484 #endif
1485     hostdata->dma_len = (p & SR_IO) ?
1486         NCR5380_dma_read_setup(instance, d, c) : 
1487         NCR5380_dma_write_setup(instance, d, c);
1488 #endif
1489 
1490     NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));
1491 
1492 #ifdef REAL_DMA
1493     NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_ENABLE_EOP_INTR | MR_MONITOR_BSY);
1494 #elif defined(REAL_DMA_POLL)
1495     NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE);
1496 #else
1497     /*
1498      * Note : on my sample board, watch-dog timeouts occured when interrupts
1499      * were not disabled for the duration of a single DMA transfer, from 
1500      * before the setting of DMA mode to after transfer of the last byte.
1501      */
1502 
1503 #if defined(PSEUDO_DMA) && !defined(UNSAFE)
1504     cli();
1505 #endif
1506     NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE);
1507 #endif /* def REAL_DMA */
1508 
1509 #if (NDEBUG & NDEBUG_DMA) & 0
1510     printk("scsi%d : mode reg = 0x%X\n", instance->host_no, NCR5380_read(MODE_REG));
1511 #endif
1512 
1513     if (p & SR_IO)
1514         NCR5380_write(START_DMA_INITIATOR_RECIEVE_REG, 0);
1515     else {
1516         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA);
1517         NCR5380_write(START_DMA_SEND_REG, 0);
1518     }
1519 
1520 #if defined(REAL_DMA_POLL)
1521     do {
1522         tmp = NCR5380_read(BUS_AND_STATUS_REG);
1523     } while ((tmp & BASR_PHASE_MATCH) && !(tmp & (BASR_BUSY_ERROR | 
1524         BASR_END_DMA_TRANSFER)));
1525 
1526 /*
1527   At this point, either we've completed DMA, or we have a phase mismatch,
1528   or we've unexpectedly lost BUSY (which is a real error).
1529 
1530   For write DMAs, we want to wait until the last byte has been
1531   transferred out over the bus before we turn off DMA mode.  Alas, there
1532   seems to be no terribly good way of doing this on a 5380 under all
1533   conditions.  For non-scatter-gather operations, we can wait until REQ
1534   and ACK both go false, or until a phase mismatch occurs.  Gather-writes
1535   are nastier, since the device will be expecting more data than we
1536   are prepared to send it, and REQ will remain asserted.  On a 53C8[01] we
1537   could test LAST BIT SENT to assure transfer (I imagine this is precisely
1538   why this signal was added to the newer chips) but on the older 538[01]
1539   this signal does not exist.  The workaround for this lack is a watchdog;
1540   we bail out of the wait-loop after a modest amount of wait-time if
1541   the usual exit conditions are not met.  Not a terribly clean or
1542   correct solution :-%
1543 
1544   Reads are equally tricky due to a nasty characteristic of the NCR5380.
1545   If the chip is in DMA mode for an READ, it will respond to a target's
1546   REQ by latching the SCSI data into the INPUT DATA register and asserting
1547   ACK, even if it has _already_ been notified by the DMA controller that
1548   the current DMA transfer has completed!  If the NCR5380 is then taken
1549   out of DMA mode, this already-acknowledged byte is lost.
1550 
1551   This is not a problem for "one DMA transfer per command" reads, because
1552   the situation will never arise... either all of the data is DMA'ed
1553   properly, or the target switches to MESSAGE IN phase to signal a
1554   disconnection (either operation bringing the DMA to a clean halt).
1555   However, in order to handle scatter-reads, we must work around the
1556   problem.  The chosen fix is to DMA N-2 bytes, then check for the
1557   condition before taking the NCR5380 out of DMA mode.  One or two extra
1558   bytes are tranferred via PIO as necessary to fill out the original
1559   request.
1560 */
1561 
1562     if (p & SR_IO) {
1563 #ifdef READ_OVERRUNS
1564       udelay(10);
1565       if (((NCR5380_read(BUS_AND_STATUS_REG) & (BASR_PHASE_MATCH|BASR_ACK)) ==
1566            (BASR_PHASE_MATCH | BASR_ACK))) {
1567         saved_data = NCR5380_read(INPUT_DATA_REGISTER);
1568         overrun = 1;
1569       }
1570 #endif
1571     } else {
1572       int limit = 100;
1573       while (((tmp = NCR5380_read(BUS_AND_STATUS_REG)) & BASR_ACK) ||
1574             (NCR5380_read(STATUS_REG) & SR_REQ)) {
1575         if (!(tmp & BASR_PHASE_MATCH)) break;
1576         if (--limit < 0) break;
1577       }
1578     }
1579 
1580 
1581 #if (NDEBUG & NDEBUG_DMA)
1582     printk("scsi%d : polled DMA transfer complete, basr 0x%X, sr 0x%X\n",
1583            instance->host_no, tmp, NCR5380_read(STATUS_REG));
1584 #endif
1585 
1586     NCR5380_write(MODE_REG, MR_BASE);
1587     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1588 
1589     residue = NCR5380_dma_residual(instance);
1590     c -= residue;
1591     *count -= c;
1592     *data += c;
1593     *phase = NCR5380_read(STATUS_REG) & PHASE_MASK;
1594 
1595 #ifdef READ_OVERRUNS
1596     if (*phase == p && (p & SR_IO) && residue == 0) {
1597       if (overrun) {
1598 #if (NDEBUG & NDEBUG_DMA)
1599         printk("Got an input overrun, using saved byte\n");
1600 #endif
1601         **data = saved_data;
1602         *data += 1;
1603         *count -= 1;
1604         cnt = toPIO = 1;
1605       } else {
1606         printk("No overrun??\n");
1607         cnt = toPIO = 2;
1608       }
1609 #if (NDEBUG & NDEBUG_DMA)
1610       printk("Doing %d-byte PIO to 0x%X\n", cnt, *data);
1611 #endif
1612       NCR5380_transfer_pio(instance, phase, &cnt, data);
1613       *count -= toPIO - cnt;
1614     }
1615 #endif        
1616 
1617 #if (NDEBUG & NDEBUG_DMA)
1618      printk("Return with data ptr = 0x%X, count %d, last 0x%X, next 0x%X\n",
1619             *data, *count, *(*data+*count-1), *(*data+*count));
1620 #endif
1621      return 0;
1622      
1623 #elif defined(REAL_DMA)
1624     return 0;
1625 #else /* defined(REAL_DMA_POLL) */
1626     if (p & SR_IO) {
1627         if (!(foo = NCR5380_pread(instance, d, c - 1))) {
1628             /*
1629              * We can't disable DMA mode after successfully transfering 
1630              * what we plan to be the last byte, since that would open up
1631              * a race condition where if the target asserted REQ before 
1632              * we got the DMA mode reset, the NCR5380 would have latched
1633              * an additional byte into the INPUT DATA register and we'd
1634              * have dropped it.
1635              * 
1636              * The workarround was to transfer one fewer bytes than we 
1637              * intended to with the pseudo-DMA read function, wait for 
1638              * the chip to latch the last byte, read it, and then disable
1639              * pseudo-DMA mode.
1640              * 
1641              * After REQ is asserted, the NCR5380 asserts DRQ and ACK.
1642              * REQ is deasserted when ACK is asserted, and not reasserted
1643              * until ACK goes false.  Since the NCR5380 won't lower ACK
1644              * until DACK is asserted, which won't happen unless we twiddle
1645              * the DMA port or we take the NCR5380 out of DMA mode, we 
1646              * can gurantee that we won't handshake another extra 
1647              * byte.
1648              */
1649 
1650             while (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ));
1651             /* Wait for clean handshake */
1652             while (NCR5380_read(STATUS_REG) & SR_REQ);
1653             d[c - 1] = NCR5380_read(INPUT_DATA_REG);
1654         }
1655     } else {
1656         int timeout;
1657         if (!(foo = NCR5380_pwrite(instance, d, c))) {
1658             /*
1659              * Wait for the last byte to be sent.  If REQ is being asserted for 
1660              * the byte we're interested, we'll ACK it and it will go false.  
1661              */
1662             if (!(hostdata->flags & FLAG_HAS_LAST_BYTE_SENT)) {
1663                 timeout = 20000;
1664 #if 1
1665 #if 1
1666                 while (!(NCR5380_read(BUS_AND_STATUS_REG) & 
1667                         BASR_DRQ) && (NCR5380_read(BUS_AND_STATUS_REG) &
1668                         BASR_PHASE_MATCH));
1669 #else
1670                 if (NCR5380_read(STATUS_REG) & SR_REQ) {
1671                     for (; timeout && 
1672                         !(NCR5380_read(BUS_AND_STATUS_REG) & BASR_ACK); 
1673                         --timeout);
1674                     for (; timeout && (NCR5380_read(STATUS_REG) & SR_REQ);
1675                         --timeout);
1676                 } 
1677 #endif
1678         
1679 
1680 #if (NDEBUG & NDEBUG_LAST_BYTE_SENT)
1681                 if (!timeout) 
1682                     printk("scsi%d : timed out on last byte\n",
1683                             instance->host_no);
1684 #endif
1685 
1686 
1687                 if (hostdata->flags & FLAG_CHECK_LAST_BYTE_SENT) {
1688                     hostdata->flags &= ~FLAG_CHECK_LAST_BYTE_SENT;
1689                     if (NCR5380_read(TARGET_COMMAND_REG) & TCR_LAST_BYTE_SENT) {
1690                         hostdata->flags |= FLAG_HAS_LAST_BYTE_SENT;
1691 #if (NDEBUG & NDEBUG_LAST_BYTE_SENT)
1692                         printk("scsi%d : last bit sent works\n", 
1693                             instance->host_no);
1694 #endif
1695                     }
1696                 }
1697             } else 
1698                 while (!(NCR5380_read(TARGET_COMMAND_REG) & TCR_LAST_BYTE_SENT));
1699 #else
1700             udelay (5);
1701 #endif
1702         }
1703     }
1704 
1705     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1706     NCR5380_write(MODE_REG, MR_BASE);
1707 
1708     *data = d + c;
1709     *count = 0;
1710     *phase = (NCR5380_read(STATUS_REG & PHASE_MASK));
1711 #if defined(PSEUDO_DMA) && !defined(UNSAFE)
1712     sti();
1713 #endif /* defined(REAL_DMA_POLL) */
1714     return foo;
1715 #endif /* def REAL_DMA */
1716 }
1717 #endif /* defined(REAL_DMA) | defined(PSEUDO_DMA) */
1718 
1719 /*
1720  * Function : NCR5380_information_transfer (struct Scsi_Host *instance)
1721  *
1722  * Purpose : run through the various SCSI phases and do as the target 
1723  *      directs us to.  Operates on the currently connected command, 
1724  *      instance->connected.
1725  *
1726  * Inputs : instance, instance for which we are doing commands
1727  *
1728  * Side effects : SCSI things happen, the disconnected queue will be 
1729  *      modified if a command disconnects, *instance->connected will
1730  *      change.
1731  *
1732  * XXX Note : we need to watch for bus free or a reset condition here 
1733  *      to recover from an unexpected bus free condition.
1734  */
1735  
1736 static void NCR5380_information_transfer (struct Scsi_Host *instance) {
     /* [previous][next][first][last][top][bottom][index][help] */
1737     NCR5380_local_declare();
1738     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) 
1739         instance->hostdata;
1740     unsigned char msgout = NOP;
1741     int len, transfersize;
1742     unsigned char *data;
1743     unsigned char phase, tmp, old_phase=0xff;
1744     Scsi_Cmnd *cmd = (Scsi_Cmnd *) hostdata->connected;
1745     NCR5380_setup(instance);
1746 
1747     while (1) {
1748         tmp = NCR5380_read(STATUS_REG);
1749         /* We only have a valid SCSI phase when REQ is asserted */
1750         if (tmp & SR_REQ) {
1751             phase = (tmp & PHASE_MASK); 
1752             if (phase != old_phase) {
1753                 old_phase = phase;
1754 #if (NDEBUG & NDEBUG_INFORMATION)
1755                 NCR5380_print_phase(instance);
1756 #endif
1757             }
1758             switch (phase) {
1759             case PHASE_DATAIN:
1760             case PHASE_DATAOUT:
1761 #if (NDEBUG & NDEBUG_NO_DATAOUT)
1762                 printk("scsi%d : NDEBUG_NO_DATAOUT set, attempted DATAOUT aborted\n",
1763                     instance->host_no);
1764                 msgout = ABORT;
1765                 NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
1766                 break;
1767 #endif
1768                 /* 
1769                  * If there is no room left in the current buffer in the
1770                  * scatter-gather list, move onto the next one.
1771                  */
1772 
1773                 if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
1774                     ++cmd->SCp.buffer;
1775                     --cmd->SCp.buffers_residual;
1776                     cmd->SCp.this_residual = cmd->SCp.buffer->length;
1777                     cmd->SCp.ptr = cmd->SCp.buffer->address;
1778 #if (NDEBUG & NDEBUG_INFORMATION)
1779                     printk("scsi%d : %d bytes and %d buffers left\n",
1780                         instance->host_no, cmd->SCp.this_residual,
1781                         cmd->SCp.buffers_residual);
1782 #endif
1783                 }
1784 
1785                 /*
1786                  * The preffered transfer method is going to be 
1787                  * PSEUDO-DMA for systems that are strictly PIO,
1788                  * since we can let the hardware do the handshaking.
1789                  *
1790                  * For this to work, we need to know the transfersize
1791                  * ahead of time, since the pseudo-DMA code will sit
1792                  * in an unconditional loop.
1793                  */
1794 
1795 #if defined(PSEUDO_DMA) || defined(REAL_DMA_POLL)
1796 #ifdef NCR5380_dma_xfer_len
1797                 if (!scsi_devices[cmd->index].borken &&
1798                     (transfersize = NCR5380_dma_xfer_len(instance, cmd)) != 0) {
1799 #else
1800                 if (!scsi_devices[cmd->index].borken && 
1801                     (transfersize = cmd->transfersize) && 
1802                     cmd->SCp.this_residual && !(cmd->SCp.this_residual % 
1803                     transfersize)) {
1804 #endif
1805                     len = transfersize;
1806                     if (NCR5380_transfer_dma(instance, &phase,
1807                         &len, (unsigned char **) &cmd->SCp.ptr)) {
1808                         /*
1809                          * If the watchdog timer fires, all future accesses to this
1810                          * device will use the polled-IO.
1811                          */ 
1812                         printk("scsi%d : switching target %d lun %d to slow handshake\n",
1813                             instance->host_no, cmd->target, cmd->lun);
1814                         scsi_devices[cmd->index].borken = 1;
1815                         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | 
1816                             ICR_ASSERT_ATN);
1817                         msgout = ABORT;
1818                     } else
1819                         cmd->SCp.this_residual -= transfersize - len;
1820                 } else
1821 #endif /* defined(REAL_DMA) || defined(REAL_DMA_POLL) */
1822                   NCR5380_transfer_pio(instance, &phase, 
1823                     (int *) &cmd->SCp.this_residual, (unsigned char **)
1824                     &cmd->SCp.ptr);
1825                 break;
1826             case PHASE_MSGIN:
1827                 /* 
1828                  * XXX - we don't handle multi-byte messages here, since we 
1829                  * shouldn't get them after the I_T_L_Q nexus is established
1830                  * for tagged queuing, and the host should initiate any 
1831                  * negotiations for sync. SCSI, etc.
1832                  */
1833                 len = 1;
1834                 data = &tmp;
1835                 NCR5380_transfer_pio(instance, &phase, &len, &data);
1836                 cmd->SCp.Message = tmp;
1837 
1838                 switch (tmp) {
1839                 /*
1840                  * Linking lets us reduce the time required to get the 
1841                  * next command out to the device, hopefully this will
1842                  * mean we don't waste another revolution due to the delays
1843                  * required by ARBITRATION and another SELECTION.
1844                  *
1845                  * In the current implementation proposal, low level drivers
1846                  * merely have to start the next command, pointed to by 
1847                  * next_link, done() is called as with unlinked commands.
1848                  */
1849 #ifdef LINKED
1850                 case LINKED_CMD_COMPLETE:
1851                 case LINKED_FLG_CMD_COMPLETE:
1852 #if (NDEBUG & NDEBUG_LINKED) 
1853                     printk("scsi%d : target %d lun %d linked command complete.\n",
1854                         instance->host_no, cmd->target, cmd->lun);
1855 #endif
1856                     /* 
1857                      * Sanity check : A linked command should only terminate with
1858                      * one of these messages if there are more linked commands
1859                      * available.
1860                      */
1861 
1862                     if (!cmd->next_link) {
1863                          printk("scsi%d : target %d lun %d linked command complete, no next_link\n"
1864                             instance->host_no, cmd->target, cmd->lun);
1865                             msgout = ABORT;
1866                             NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
1867                                 ICR_ASSERT_ATN);
1868                             break;
1869                     }
1870 
1871                     initialize_SCp(cmd->next_link);
1872                     /* The next command is still part of this process */
1873                     cmd->next_link->tag = cmd->tag;
1874                     cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8); 
1875 #if (NDEBUG & NDEBUG_LINKED) 
1876                     printk("scsi%d : target %d lun %d linked request done, calling scsi_done().\n",
1877                         instance->host_no, cmd->target, cmd->lun);
1878 #endif
1879                     cmd->scsi_done(cmd);
1880                     cmd = hostdata->connected;
1881                     break;
1882 #endif /* def LINKED */
1883                 case ABORT:
1884                 case COMMAND_COMPLETE: 
1885                     hostdata->connected = NULL;
1886 #if (NDEBUG & NDEBUG_QUEUES)
1887                     printk("scsi%d : command for target %d, lun %d completed\n",
1888                         instance->host_no, cmd->target, cmd->lun);
1889 #endif
1890                     hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
1891 
1892                     /* 
1893                      * I'm not sure what the correct thing to do here is : 
1894                      * 
1895                      * If the command that just executed is NOT a request 
1896                      * sense, the obvious thing to do is to set the result
1897                      * code to the values of the stored parameters.
1898                      * 
1899                      * If it was a REQUEST SENSE command, we need some way 
1900                      * to differentiate between the failure code of the original
1901                      * and the failure code of the REQUEST sense - the obvious
1902                      * case is success, where we fall through and leave the result
1903                      * code unchanged.
1904                      * 
1905                      * The non-obvious place is where the REQUEST SENSE failed 
1906                      */
1907 
1908                     if (cmd->cmnd[0] != REQUEST_SENSE) 
1909                         cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8); 
1910                     else if (cmd->SCp.Status != GOOD)
1911                         cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);
1912                     
1913 #ifdef AUTOSENSE
1914                     if ((cmd->cmnd[0] != REQUEST_SENSE) && 
1915                         (cmd->SCp.Status == CHECK_CONDITION)) {
1916 #if (NDEBUG & NDEBUG_AUTOSENSE) 
1917                         printk("scsi%d : performing request sense\n", 
1918                             instance->host_no);
1919 #endif
1920                         cmd->cmnd[0] = REQUEST_SENSE;
1921                         cmd->cmnd[1] &= 0xe0;
1922                         cmd->cmnd[2] = 0;
1923                         cmd->cmnd[3] = 0;
1924                         cmd->cmnd[4] = sizeof(cmd->sense_buffer);
1925                         cmd->cmnd[5] = 0;
1926 
1927                         cmd->SCp.buffer = NULL;
1928                         cmd->SCp.buffers_residual = 0;
1929                         cmd->SCp.ptr = (char *) cmd->sense_buffer;
1930                         cmd->SCp.this_residual = sizeof(cmd->sense_buffer);
1931 
1932                         cli();
1933                         cmd->host_scribble = (unsigned char *) 
1934                             hostdata->issue_queue;
1935                         hostdata->issue_queue = (Scsi_Cmnd *) cmd;
1936                         sti();
1937 #if (NDEBUG & NDEBUG_QUEUES)
1938                         printk("scsi%d : REQUEST SENSE added to head of issue queue\n");
1939 #endif
1940                    } else
1941 #endif /* def AUTOSENSE */
1942                         cmd->scsi_done(cmd);
1943 
1944                     NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
1945                     
1946                     while ((NCR5380_read(STATUS_REG) & SR_BSY) && 
1947                         !hostdata->connected);
1948                     return;
1949                 case MESSAGE_REJECT:
1950                     switch (hostdata->last_message) {
1951                     case HEAD_OF_QUEUE_TAG:
1952                     case ORDERED_QUEUE_TAG:
1953                     case SIMPLE_QUEUE_TAG:
1954                         scsi_devices[cmd->index].tagged_queue = 0;
1955                         hostdata->busy[cmd->target] |= (1 << cmd->lun);
1956                         break;
1957                     default:
1958                         break;
1959                     }
1960                 case DISCONNECT:
1961                     scsi_devices[cmd->index].disconnect = 1;
1962                     cli();
1963                     cmd->host_scribble = (unsigned char *) 
1964                         hostdata->disconnected_queue;
1965                     hostdata->connected = NULL;
1966                     hostdata->disconnected_queue = cmd;
1967                     sti();
1968 #if (NDEBUG & NDEBUG_QUEUES)
1969                     printk("scsi%d : command for target %d lun %d was moved from connected to"
1970                            "  the disconnected_queue\n", instance->host_no, 
1971                             cmd->target, cmd->lun);
1972 #endif
1973 
1974                     /* Enable reselect interupts */
1975                     NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
1976                     /* Wait for bus free to avoid nasty timeouts */
1977                     while ((NCR5380_read(STATUS_REG) & SR_BSY) && 
1978                         !hostdata->connected);
1979                     return;
1980                 /* 
1981                  * The SCSI data pointer is *IMPLICITLY* saved on a disconnect
1982                  * operation, in violation of the SCSI spec so we can safely 
1983                  * ignore SAVE/RESTORE pointers calls.
1984                  *
1985                  * Unfortunately, some disks violate the SCSI spec and 
1986                  * don't issue the required SAVE_POINTERS message before
1987                  * disconnecting, and we have to break spec to remain 
1988                  * compatable.
1989                  */
1990                 case SAVE_POINTERS:
1991                 case RESTORE_POINTERS:
1992                     break;
1993                 default:
1994 /* 
1995  * XXX rejected messages should be handled in the pio data transfer phase,
1996  * since ATN should be raised before ACK goes false when we reject a message
1997  */
1998 
1999                     printk("Unknown message!\n");
2000 
2001 #ifdef notyet
2002                 /* 
2003                  * If we get something wierd that we aren't expecting, 
2004                  * reject it.
2005                  */
2006                     msgout = MESSAGE_REJECT;
2007                     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | 
2008                         ICR_ASSERT_ATN);
2009 #endif 
2010                     break;
2011                 } /* switch (tmp) */
2012                 break;
2013             case PHASE_MSGOUT:
2014                 len = 1;
2015                 data = &msgout;
2016                 hostdata->last_message = msgout;
2017                 NCR5380_transfer_pio(instance, &phase, &len, &data);
2018                 if (msgout == ABORT) {
2019                     hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
2020                     hostdata->connected = NULL;
2021                     cmd->result = DID_ERROR << 16;
2022                     cmd->scsi_done(cmd);
2023                     NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
2024                     return;
2025                 }
2026                 msgout = NOP;
2027                 break;
2028             case PHASE_CMDOUT:
2029                 len = COMMAND_SIZE(cmd->cmnd[0]);
2030                 data = cmd->cmnd;
2031                 /* 
2032                  * XXX for performance reasons, on machines with a 
2033                  * PSEUDO-DMA architecture we should probably 
2034                  * use the dma transfer function.  
2035                  */
2036                 NCR5380_transfer_pio(instance, &phase, &len, 
2037                     &data);
2038 #ifdef USLEEP
2039                 if (!disconnect && should_disconnect(cmd->cmnd[0])) {
2040                     hostdata->time_expires = jiffies + USLEEP_SLEEP;
2041 #if (NDEBUG & NDEBUG_USLEEP)
2042                 printk("scsi%d : issued command, sleeping until %ul\n", instance->host_no,
2043                     hostdata->time_expires);
2044 #endif
2045                     NCR5380_set_timer (instance);
2046                     return;
2047                 }
2048 #endif /* def USLEEP */
2049                 break;
2050             case PHASE_STATIN:
2051                 len = 1;
2052                 data = &tmp;
2053                 NCR5380_transfer_pio(instance, &phase, &len, &data);
2054                 cmd->SCp.Status = tmp;
2055                 break;
2056             default:
2057                 printk("scsi%d : unknown phase\n", instance->host_no);
2058 #ifdef NDEBUG
2059                 NCR5380_print(instance);
2060 #endif
2061             } /* switch(phase) */
2062         } /* if (tmp * SR_REQ) */ 
2063 #ifdef USLEEP
2064         else {
2065             if (!disconnect && hostdata->time_expires && jiffies > 
2066                 hostdata->time_expires) {
2067                 hostdata->time_expires = jiffies + USLEEP_SLEEP;
2068 #if (NDEBUG & NDEBUG_USLEEP)
2069                 printk("scsi%d : poll timed out, sleeping until %ul\n", instance->host_no,
2070                     hostdata->time_expires);
2071 #endif
2072                 NCR5380_set_timer (instance);
2073                 return;
2074             }
2075         }
2076 #endif
2077     } /* while (1) */
2078 }
2079 
2080 /*
2081  * Function : void NCR5380_reselect (struct Scsi_Host *instance)
2082  *
2083  * Purpose : does reselection, initializing the instance->connected 
2084  *      field to point to the Scsi_Cmnd for which the I_T_L or I_T_L_Q 
2085  *      nexus has been restablished,
2086  *      
2087  * Inputs : instance - this instance of the NCR5380.
2088  *
2089  */
2090 
2091 
2092 static void NCR5380_reselect (struct Scsi_Host *instance) {
     /* [previous][next][first][last][top][bottom][index][help] */
2093     NCR5380_local_declare();
2094     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *)
2095         instance->hostdata;
2096     unsigned char target_mask;
2097     unsigned char lun, phase;
2098     int len;
2099 #ifdef SCSI2
2100     unsigned char tag;
2101 #endif
2102     unsigned char msg[3];
2103     unsigned char *data;
2104     Scsi_Cmnd *tmp = NULL, *prev;
2105     int abort = 0;
2106     NCR5380_setup(instance);
2107 
2108     target_mask = NCR5380_read(CURRENT_SCSI_DATA_REG) & ~(hostdata->id_mask);
2109 
2110 #if (NDEBUG & NDEBUG_RESELECTION)
2111     printk("scsi%d : reselect\n", instance->host_no);
2112 #endif
2113 
2114     /* 
2115      * At this point, we have detected that our SCSI ID is on the bus,
2116      * SEL is true and BSY was false for at least one bus settle delay
2117      * (400 ns).
2118      *
2119      * We must assert BSY ourselves, until the target drops the SEL
2120      * signal.
2121      */
2122 
2123     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_BSY);
2124     
2125     while (NCR5380_read(STATUS_REG) & SR_SEL);
2126     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
2127 
2128     /*
2129      * Wait for target to go into MSGIN.
2130      */
2131 
2132     while (!(NCR5380_read(STATUS_REG) & SR_REQ));
2133 
2134     len = 3;
2135     data = msg;
2136     phase = PHASE_MSGIN;
2137     NCR5380_transfer_pio(instance, &phase, &len, &data);
2138 
2139 #ifdef SCSI2
2140     /*
2141      * If there was no residual from the attempt to transfer three bytes, then
2142      * the target sent the one byte IDENTIFY message followed by a two byte
2143      * queue message.
2144      *
2145      * If there were two bytes of residual, we got the IDENTIFY message
2146      * only.
2147      *
2148      * If there was one byte of residual, we got the IDENTIFY message
2149      * followed by a RESTORE pointers message (which was ignored - 
2150      * see MSGIN phase of the NCR5380_information_transfer() function.
2151      */
2152 
2153     if (!len) 
2154         tag = msg[2];
2155     else
2156         tag = 0;
2157 #endif
2158 
2159     if (!msg[0] & 0x80) {
2160         printk("scsi%d : expecting IDENTIFY message, got ",
2161             instance->host_no);
2162         print_msg(msg);
2163         abort = 1;
2164     } else {
2165 
2166         lun = (msg[0] & 0x07);
2167 
2168         /* 
2169          * Find the command corresponding to the I_T_L or I_T_L_Q  nexus we 
2170          * just restablished, and remove it from the disconnected queue.
2171          */
2172 
2173         for (tmp = (Scsi_Cmnd *) hostdata->disconnected_queue, prev = NULL; 
2174             tmp; prev = tmp, tmp = (Scsi_Cmnd *) tmp->host_scribble) 
2175             if ((target_mask == (1 << tmp->target)) && (lun == tmp->lun)
2176 #ifdef SCSI2
2177             && (tag == tmp->tag) 
2178 #endif
2179 ) {
2180             if (prev)
2181                 prev->host_scribble = tmp->host_scribble;
2182             else
2183                 hostdata->disconnected_queue = (Scsi_Cmnd *) tmp->host_scribble;
2184             tmp->host_scribble = NULL;
2185             break;
2186         }
2187 
2188         if (!tmp) {
2189 #ifdef SCSI2
2190             printk("scsi%d : warning : target bitmask %02x lun %d tag %d not in disconnect_queue.\n",
2191                     instance->host_no, target_mask, lun, tag);
2192 #else
2193             printk("scsi%d : warning : target bitmask %02x lun %d not in disconnect_queue.\n",
2194                     instance->host_no, target_mask, lun);
2195 #endif
2196         /* 
2197          * Since we have an established nexus that we can't do anything with,
2198          * we must abort it.  
2199          */
2200         abort = 1;
2201         }
2202     }
2203 
2204     if (abort) {
2205         msg[0] = ABORT;
2206         len = 1;
2207         data = msg;
2208         phase = PHASE_MSGOUT;
2209         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
2210         NCR5380_transfer_pio(instance, &phase, &len, &data);
2211     } else {
2212         hostdata->connected = tmp;
2213 #if (NDEBUG & NDEBUG_RESELECTION)
2214         printk"scsi%d : nexus established, target = %d, lun = %d, tag = %d\n",
2215             instance->host_no, cmd->target, cmd->lun, cmd->tag);
2216 #endif
2217     }
2218 }
2219 
2220 /*
2221  * Function : void NCR5380_dma_complete (struct Scsi_Host *instance)
2222  *
2223  * Purpose : called by interrupt handler when DMA finishes or a phase
2224  *      mismatch occurs (which would finish the DMA transfer).  
2225  *
2226  * Inputs : instance - this instance of the NCR5380.
2227  *
2228  * Returns : pointer to the Scsi_Cmnd structure for which the I_T_L
2229  *      nexus has been restablished, on failure NULL is returned.
2230  */
2231 
2232 #ifdef REAL_DMA
2233 static void NCR5380_dma_complete (NCR5380_instance *instance) {
     /* [previous][next][first][last][top][bottom][index][help] */
2234     NCR5380_local_declare();
2235     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *
2236         instance->hostdata);
2237     int transferred;
2238     NCR5380_setup(instance);
2239     
2240     /*
2241      * XXX this might not be right.
2242      *
2243      * Wait for final byte to transfer, ie wait for ACK to go false.
2244      *
2245      * We should use the Last Byte Sent bit, unfortunately this is 
2246      * not available on the 5380/5381 (only the various CMOS chips)
2247      */
2248 
2249     while (NCR5380_read(BUS_AND_STATUS_REG) & BASR_ACK);
2250 
2251     NCR5380_write(MODE_REG, MR_BASE);
2252     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
2253 
2254     /*
2255      * The only places we should see a phase mismatch and have to send
2256      * data from the same set of pointers will be the data transfer
2257      * phases.  So, residual, requested length are only important here.
2258      */
2259 
2260     if (!(hostdata->connected->SCp.phase & SR_CD)) {
2261         transferred = instance->dmalen - NCR5380_dma_residual();
2262         hostdata->connected->SCp.this_residual -= transferred;
2263         hostdata->connected->SCp.ptr += transferred;
2264     }
2265 }
2266 #endif /* def REAL_DMA */
2267 
2268 /*
2269  * Function : int NCR5380_abort (Scsi_Cmnd *cmd, int code)
2270  *
2271  * Purpose : abort a command
2272  *
2273  * Inputs : cmd - the Scsi_Cmnd to abort, code - code to set the 
2274  *      host byte of the result field to, if zero DID_ABORTED is 
2275  *      used.
2276  *
2277  * Returns : 0 - success, -1 on failure.
2278  *
2279  * XXX - there is no way to abort the command that is currently 
2280  *       connected, you have to wait for it to complete.  If this is 
2281  *       a problem, we could implement longjmp() / setjmp(), setjmp()
2282  *       called where the loop started in NCR5380_main().
2283  */
2284 
2285 #ifndef NCR5380_abort
2286 static
2287 #endif
2288 int NCR5380_abort (Scsi_Cmnd *cmd, int code) {
     /* [previous][next][first][last][top][bottom][index][help] */
2289     NCR5380_local_declare();
2290     struct Scsi_Host *instance = cmd->host;
2291     struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *)
2292         instance->hostdata;
2293     Scsi_Cmnd *tmp, **prev;
2294     unsigned char msg, phase, *msgptr;
2295     int len;
2296 
2297     cli();
2298     NCR5380_setup(instance);
2299     
2300 #if (NDEBUG & NDEBUG_ABORT)
2301     printk("scsi%d : abort called\n", instance->host_no);
2302     printk("        basr 0x%X, sr 0x%X\n", 
2303            NCR5380_read(BUS_AND_STATUS_REG), NCR5380_read(STATUS_REG));
2304 #endif
2305 /* 
2306  * Case 1 : If the command hasn't been issued yet, we simply remove it 
2307  *          from the issue queue.
2308  */
2309     for (prev = (Scsi_Cmnd **) &(hostdata->issue_queue), 
2310         tmp = (Scsi_Cmnd *) hostdata->issue_queue;
2311         tmp; prev = (Scsi_Cmnd **) &(tmp->host_scribble), tmp = 
2312         (Scsi_Cmnd *) tmp->host_scribble) 
2313         if (cmd == tmp) {
2314             (*prev) = (Scsi_Cmnd *) tmp->host_scribble;
2315             tmp->host_scribble = NULL;
2316             tmp->result = (code ? code : DID_ABORT) << 16;
2317             sti();
2318 #if (NDEBUG & NDEBUG_ABORT)
2319     printk("scsi%d : abort removed command from issue queue.\n", 
2320         instance->host_no);
2321 #endif
2322             tmp->done(tmp);
2323             return 0;
2324         }
2325 
2326 /* 
2327  * Case 2 : If any commands are connected, we're going to fail the abort
2328  *          and let the high level SCSI driver retry at a later time or 
2329  *          issue a reset.
2330  *
2331  *          Timeouts, and therefore aborted commands, will be highly unlikely
2332  *          and handling them cleanly in this situation would make the common
2333  *          case of noresets less efficient, and would pollute our code.  So,
2334  *          we fail.
2335  */
2336 
2337     if (hostdata->connected) {
2338         sti();
2339 #if (NDEBUG & NDEBUG_ABORT)
2340     printk("scsi%d : abort failed, command connected.\n", instance->host_no);
2341 #endif
2342         return -1;
2343     }
2344 
2345 /*
2346  * Case 3: If the command is currently disconnected from the bus, and 
2347  *      there are no connected commands, we reconnect the I_T_L or 
2348  *      I_T_L_Q nexus associated with it, go into message out, and send 
2349  *      an abort message.
2350  *
2351  * This case is especially ugly. In order to resetablish the nexus, we
2352  * need to call NCR5380_select().  The easiest way to implement this 
2353  * function was to abort if the bus was busy, and let the interrupt
2354  * handler triggered on the SEL for reselect take care of lost arbitrations
2355  * where necessary, meaning interrupts need to be enabled.
2356  *
2357  * When interrupts are enabled, the queues may change - so we 
2358  * can't remove it from the disconnected queue before selecting it
2359  * because that could cause a failure in hashing the nexus if that 
2360  * device reselected.
2361  * 
2362  * Since the queues may change, we can't use the pointers from when we
2363  * first locate it.
2364  *
2365  * So, we must first locate the command, and if NCR5380_select()
2366  * succeeds, then issue the abort, relocate the command and remove
2367  * it from the disconnected queue.
2368  */
2369 
2370     for (tmp = (Scsi_Cmnd *) hostdata->disconnected_queue; tmp; 
2371         tmp = (Scsi_Cmnd *) tmp->host_scribble) 
2372         if (cmd == tmp) {
2373             sti(); 
2374 #if (NDEBUG & NDEBUG_ABORT)
2375     printk("scsi%d : aborting disconnected command.\n", instance->host_no);
2376 #endif
2377   
2378             if (NCR5380_select (instance, cmd, (int) cmd->tag)) 
2379                 return 1;
2380 
2381 #if (NDEBUG & NDEBUG_ABORT)
2382     printk("scsi%d : nexus restablished.\n", instance->host_no);
2383 #endif
2384 
2385             msg = ABORT;
2386             msgptr = &msg;
2387             len = 1;
2388             phase = PHASE_MSGOUT;
2389             NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
2390             NCR5380_transfer_pio (instance, &phase, &len, &msgptr);
2391 
2392             cli();
2393             for (prev = (Scsi_Cmnd **) &(hostdata->disconnected_queue), 
2394                 tmp = (Scsi_Cmnd *) hostdata->disconnected_queue;
2395                 tmp; prev = (Scsi_Cmnd **) &(tmp->host_scribble), tmp = 
2396                 (Scsi_Cmnd *) tmp->host_scribble) 
2397                     if (cmd == tmp) {
2398                     *prev = (Scsi_Cmnd *) tmp->host_scribble;
2399                     tmp->host_scribble = NULL;
2400                     tmp->result = (code ? code : DID_ABORT) << 16;
2401                     sti();
2402                     tmp->done(tmp);
2403                     return 0;
2404                 }
2405         }
2406 
2407 /*
2408  * Case 4 : If we reached this point, the command was not found in any of 
2409  *          the queues.
2410  *
2411  * We probably reached this point because of an unlikely race condition
2412  * between the command completing successfully and the abortion code,
2413  * so we won't panic, but we will notify the user in case somethign really
2414  * broke.
2415  */
2416 
2417     sti();
2418     printk("scsi%d : warning : SCSI command probably completed successfully\n"
2419            "         before abortion\n", instance->host_no); 
2420     return 0;
2421 }
2422 
2423 
2424 /* 
2425  * Function : int NCR5380_reset (Scsi_Cmnd *cmd)
2426  * 
2427  * Purpose : reset the SCSI bus.
2428  *
2429  * Returns : 0
2430  *
2431  */ 
2432 
2433 #ifndef NCR5380_reset
2434 static
2435 #endif
2436 int NCR5380_reset (Scsi_Cmnd *cmd) {
     /* [previous][next][first][last][top][bottom][index][help] */
2437     NCR5380_local_declare();
2438     NCR5380_setup(cmd->host);
2439 
2440     cli();
2441     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
2442     udelay(1);
2443     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
2444     sti();
2445 
2446     return 0;
2447 }

/* [previous][next][first][last][top][bottom][index][help] */