in2000.c

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 * status byte is stored.
 */

   cmd->SCp.Status = ILLEGAL_STATUS_BYTE;

/* We need to disable interrupts before messing with the input
 * queue and calling in2000_execute().
 */

   save_flags(flags);
   cli();

   /*
    * Add the cmd to the end of 'input_Q'. Note that REQUEST_SENSE
    * commands are added to the head of the queue so that the desired
    * sense data is not lost before REQUEST_SENSE executes.
    */

   if (!(hostdata->input_Q) || (cmd->cmnd[0] == REQUEST_SENSE)) {
      cmd->host_scribble = (uchar *)hostdata->input_Q;
      hostdata->input_Q = cmd;
      }
   else {   /* find the end of the queue */
      for (tmp=(Scsi_Cmnd *)hostdata->input_Q; tmp->host_scribble;
            tmp=(Scsi_Cmnd *)tmp->host_scribble)
         ;
      tmp->host_scribble = (uchar *)cmd;
      }

/* We know that there's at least one command in 'input_Q' now.
 * Go see if any of them are runnable!
 */

   in2000_execute(cmd->host);

DB(DB_QUEUE_COMMAND,printk(")Q-%ld ",cmd->pid))

   restore_flags(flags);
   return 0;
}



/*
 * This routine attempts to start a scsi command. If the host_card is
 * already connected, we give up immediately. Otherwise, look through
 * the input_Q, using the first command we find that's intended
 * for a currently non-busy target/lun.
 * Note that this function is always called with interrupts already
 * disabled (either from in2000_queuecommand() or in2000_intr()).
 */
static void in2000_execute (struct Scsi_Host *instance)
{
struct IN2000_hostdata *hostdata;
Scsi_Cmnd *cmd, *prev;
int i;
unsigned short *sp;
unsigned short f;
unsigned short flushbuf[16];


   hostdata = (struct IN2000_hostdata *)instance->hostdata;

DB(DB_EXECUTE,printk("EX("))

   if (hostdata->selecting || hostdata->connected) {

DB(DB_EXECUTE,printk(")EX-0 "))

      return;
      }

    /*
     * Search through the input_Q for a command destined
     * for an idle target/lun.
     */

   cmd = (Scsi_Cmnd *)hostdata->input_Q;
   prev = 0;
   while (cmd) {
      if (!(hostdata->busy[cmd->target] & (1 << cmd->lun)))
         break;
      prev = cmd;
      cmd = (Scsi_Cmnd *)cmd->host_scribble;
      }

   /* quit if queue empty or all possible targets are busy */

   if (!cmd) {

DB(DB_EXECUTE,printk(")EX-1 "))

      return;
      }

   /*  remove command from queue */
   
   if (prev)
      prev->host_scribble = cmd->host_scribble;
   else
      hostdata->input_Q = (Scsi_Cmnd *)cmd->host_scribble;

#ifdef PROC_STATISTICS
   hostdata->cmd_cnt[cmd->target]++;
#endif

/*
 * Start the selection process
 */

   if (is_dir_out(cmd))
      write_3393(hostdata,WD_DESTINATION_ID, cmd->target);
   else
      write_3393(hostdata,WD_DESTINATION_ID, cmd->target | DSTID_DPD);

/* Now we need to figure out whether or not this command is a good
 * candidate for disconnect/reselect. We guess to the best of our
 * ability, based on a set of hierarchical rules. When several
 * devices are operating simultaneously, disconnects are usually
 * an advantage. In a single device system, or if only 1 device
 * is being accessed, transfers usually go faster if disconnects
 * are not allowed:
 *
 * + Commands should NEVER disconnect if hostdata->disconnect =
 *   DIS_NEVER (this holds for tape drives also), and ALWAYS
 *   disconnect if hostdata->disconnect = DIS_ALWAYS.
 * + Tape drive commands should always be allowed to disconnect.
 * + Disconnect should be allowed if disconnected_Q isn't empty.
 * + Commands should NOT disconnect if input_Q is empty.
 * + Disconnect should be allowed if there are commands in input_Q
 *   for a different target/lun. In this case, the other commands
 *   should be made disconnect-able, if not already.
 *
 * I know, I know - this code would flunk me out of any
 * "C Programming 101" class ever offered. But it's easy
 * to change around and experiment with for now.
 */

   cmd->SCp.phase = 0;  /* assume no disconnect */
   if (hostdata->disconnect == DIS_NEVER)
      goto no;
   if (hostdata->disconnect == DIS_ALWAYS)
      goto yes;
   if (cmd->device->type == 1)   /* tape drive? */
      goto yes;
   if (hostdata->disconnected_Q) /* other commands disconnected? */
      goto yes;
   if (!(hostdata->input_Q))     /* input_Q empty? */
      goto no;
   for (prev=(Scsi_Cmnd *)hostdata->input_Q; prev;
         prev=(Scsi_Cmnd *)prev->host_scribble) {
      if ((prev->target != cmd->target) || (prev->lun != cmd->lun)) {
         for (prev=(Scsi_Cmnd *)hostdata->input_Q; prev;
               prev=(Scsi_Cmnd *)prev->host_scribble)
            prev->SCp.phase = 1;
         goto yes;
         }
      }
   goto no;

yes:
   cmd->SCp.phase = 1;

#ifdef PROC_STATISTICS
   hostdata->disc_allowed_cnt[cmd->target]++;
#endif

no:
   write_3393(hostdata,WD_SOURCE_ID,((cmd->SCp.phase)?SRCID_ER:0));

   write_3393(hostdata,WD_TARGET_LUN, cmd->lun);
   write_3393(hostdata,WD_SYNCHRONOUS_TRANSFER,hostdata->sync_xfer[cmd->target]);
   hostdata->busy[cmd->target] |= (1 << cmd->lun);

   if ((hostdata->level2 <= L2_NONE) ||
       (hostdata->sync_stat[cmd->target] == SS_UNSET)) {

         /*
          * Do a 'Select-With-ATN' command. This will end with
          * one of the following interrupts:
          *    CSR_RESEL_AM:  failure - can try again later.
          *    CSR_TIMEOUT:   failure - give up.
          *    CSR_SELECT:    success - proceed.
          */

      hostdata->selecting = cmd;

/* Every target has its own synchronous transfer setting, kept in
 * the sync_xfer array, and a corresponding status byte in sync_stat[].
 * Each target's sync_stat[] entry is initialized to SS_UNSET, and its
 * sync_xfer[] entry is initialized to the default/safe value. SS_UNSET
 * means that the parameters are undetermined as yet, and that we
 * need to send an SDTR message to this device after selection is
 * complete. We set SS_FIRST to tell the interrupt routine to do so,
 * unless we don't want to even _try_ synchronous transfers: In this
 * case we set SS_SET to make the defaults final.
 */
      if (hostdata->sync_stat[cmd->target] == SS_UNSET) {
         if (hostdata->sync_off & (1 << cmd->target))
            hostdata->sync_stat[cmd->target] = SS_SET;
         else
            hostdata->sync_stat[cmd->target] = SS_FIRST;
         }
      hostdata->state = S_SELECTING;
      write_3393_count(hostdata,0); /* this guarantees a DATA_PHASE interrupt */
      write_3393_cmd(hostdata,WD_CMD_SEL_ATN);
      }

   else {

         /*
          * Do a 'Select-With-ATN-Xfer' command. This will end with
          * one of the following interrupts:
          *    CSR_RESEL_AM:  failure - can try again later.
          *    CSR_TIMEOUT:   failure - give up.
          *    anything else: success - proceed.
          */

      hostdata->connected = cmd;
      write_3393(hostdata,WD_COMMAND_PHASE, 0);

   /* copy command_descriptor_block into WD chip
    * (take advantage of auto-incrementing)
    */

      write1_io(WD_CDB_1, IO_WD_ADDR);
      for (i=0; i<cmd->cmd_len; i++)
         write1_io(cmd->cmnd[i], IO_WD_DATA);

   /* The wd33c93 only knows about Group 0, 1, and 5 commands when
    * it's doing a 'select-and-transfer'. To be safe, we write the
    * size of the CDB into the OWN_ID register for every case. This
    * way there won't be problems with vendor-unique, audio, etc.
    */

      write_3393(hostdata, WD_OWN_ID, cmd->cmd_len);

   /* When doing a non-disconnect command, we can save ourselves a DATA
    * phase interrupt later by setting everything up now. With writes we
    * need to pre-fill the fifo; if there's room for the 32 flush bytes,
    * put them in there too - that'll avoid a fifo interrupt. Reads are
    * somewhat simpler.
    * KLUDGE NOTE: It seems that you can't completely fill the fifo here:
    * This results in the IO_FIFO_COUNT register rolling over to zero,
    * and apparently the gate array logic sees this as empty, not full,
    * so the 3393 chip is never signalled to start reading from the
    * fifo. Or maybe it's seen as a permanent fifo interrupt condition.
    * Regardless, we fix this by temporarily pretending that the fifo
    * is 16 bytes smaller. (I see now that the old driver has a comment
    * about "don't fill completely" in an analogous place - must be the
    * same deal.) This results in CDROM, swap partitions, and tape drives
    * needing an extra interrupt per write command - I think we can live
    * with that!
    */

      if (!(cmd->SCp.phase)) {
         write_3393_count(hostdata, cmd->SCp.this_residual);
         write_3393(hostdata,WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_BUS);
         write1_io(0, IO_FIFO_WRITE);  /* clear fifo counter, write mode */

         if (is_dir_out(cmd)) {
            hostdata->fifo = FI_FIFO_WRITING;
            if ((i = cmd->SCp.this_residual) > (IN2000_FIFO_SIZE - 16) )
               i = IN2000_FIFO_SIZE - 16;
            cmd->SCp.have_data_in = i;    /* this much data in fifo */
            i >>= 1;                      /* Gulp. Assuming modulo 2. */
            sp = (unsigned short *)cmd->SCp.ptr;
            f = hostdata->io_base + IO_FIFO;

#ifdef FAST_WRITE_IO

            FAST_WRITE2_IO();
#else
            while (i--)
               write2_io(*sp++,IO_FIFO);

#endif

      /* Is there room for the flush bytes? */

            if (cmd->SCp.have_data_in <= ((IN2000_FIFO_SIZE - 16) - 32)) {
               sp = flushbuf;
               i = 16;

#ifdef FAST_WRITE_IO

               FAST_WRITE2_IO();
#else
               while (i--)
                  write2_io(0,IO_FIFO);

#endif

               }
            }

         else {
            write1_io(0, IO_FIFO_READ);   /* put fifo in read mode */
            hostdata->fifo = FI_FIFO_READING;
            cmd->SCp.have_data_in = 0;    /* nothing transfered yet */
            }

         }
      else {
         write_3393_count(hostdata,0); /* this guarantees a DATA_PHASE interrupt */
         }
      hostdata->state = S_RUNNING_LEVEL2;
      write_3393_cmd(hostdata,WD_CMD_SEL_ATN_XFER);
      }

   /*
    * Since the SCSI bus can handle only 1 connection at a time,
    * we get out of here now. If the selection fails, or when
    * the command disconnects, we'll come back to this routine
    * to search the input_Q again...
    */
      
DB(DB_EXECUTE,printk("%s%ld)EX-2 ",(cmd->SCp.phase)?"d:":"",cmd->pid))

}



static void transfer_pio(uchar *buf, int cnt,
                  int data_in_dir, struct IN2000_hostdata *hostdata)
{
uchar asr;

DB(DB_TRANSFER,printk("(%p,%d,%s)",buf,cnt,data_in_dir?"in":"out"))

   write_3393(hostdata,WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
   write_3393_count(hostdata,cnt);
   write_3393_cmd(hostdata,WD_CMD_TRANS_INFO);
   if (data_in_dir) {
      do {
         asr = READ_AUX_STAT();
         if (asr & ASR_DBR)
            *buf++ = read_3393(hostdata,WD_DATA);
         } while (!(asr & ASR_INT));
      }
   else {
      do {
         asr = READ_AUX_STAT();
         if (asr & ASR_DBR)
            write_3393(hostdata,WD_DATA, *buf++);
         } while (!(asr & ASR_INT));
      }

   /* Note: we are returning with the interrupt UN-cleared.
   * Since (presumably) an entire I/O operation has
   * completed, the bus phase is probably different, and
   * the interrupt routine will discover this when it
   * responds to the uncleared int.
   */

}



static void transfer_bytes(Scsi_Cmnd *cmd, int data_in_dir)
{
struct IN2000_hostdata *hostdata;
unsigned short *sp;
unsigned short f;
int i;

   hostdata = (struct IN2000_hostdata *)cmd->host->hostdata;

/* Normally, you'd expect 'this_residual' to be non-zero here.
 * In a series of scatter-gather transfers, however, this
 * routine will usually be called with 'this_residual' equal
 * to 0 and 'buffers_residual' non-zero. This means that a
 * previous transfer completed, clearing 'this_residual', and
 * now we need to setup the next scatter-gather buffer as the
 * source or destination for THIS transfer.
 */
   if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
      ++cmd->SCp.buffer;
      --cmd->SCp.buffers_residual;
      cmd->SCp.this_residual = cmd->SCp.buffer->length;
      cmd->SCp.ptr = cmd->SCp.buffer->address;
      }

/* Set up hardware registers */