[SCSI] aic79xx: sequencer fixes

This patch updates the aic79xx sequencer with latest fixes from adaptec.
The sequencer code now corresponds with adaptec version 2.0.15.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 120 insertions, 23 deletions

diff --git a/drivers/scsi/aic7xxx/aic79xx.seq b/drivers/scsi/aic7xxx/aic79xx.seq
index bef1f9d369b6..58bc17591b54 100644
--- a/drivers/scsi/aic7xxx/aic79xx.seq
+++ b/drivers/scsi/aic7xxx/aic79xx.seq
@@ -1,7 +1,7 @@
 /*
  * Adaptec U320 device driver firmware for Linux and FreeBSD.
  *
- * Copyright (c) 1994-2001 Justin T. Gibbs.
+ * Copyright (c) 1994-2001, 2004 Justin T. Gibbs.
  * Copyright (c) 2000-2002 Adaptec Inc.
  * All rights reserved.
  *
@@ -40,7 +40,7 @@
  * $FreeBSD$
  */
 
-VERSION = "$Id: //depot/aic7xxx/aic7xxx/aic79xx.seq#119 $"
+VERSION = "$Id: //depot/aic7xxx/aic7xxx/aic79xx.seq#120 $"
 PATCH_ARG_LIST = "struct ahd_softc *ahd"
 PREFIX = "ahd_"
 
@@ -110,10 +110,8 @@ check_waiting_list:
          * one last time.
          */
         test    SSTAT0, SELDO jnz select_out;
-END_CRITICAL;
         call    start_selection;
 idle_loop_checkbus:
-BEGIN_CRITICAL;
         test    SSTAT0, SELDO jnz select_out;
 END_CRITICAL;
         test    SSTAT0, SELDI jnz select_in;
@@ -294,7 +292,6 @@ fetch_new_scb_inprog:
         test    CCSCBCTL, ARRDONE jz return;
 fetch_new_scb_done:
         and     CCSCBCTL, ~(CCARREN|CCSCBEN);
-        bmov    REG0, SCBPTR, 2;
         clr     A;
         add     CMDS_PENDING, 1;
         adc     CMDS_PENDING[1], A;
@@ -316,43 +313,117 @@ fetch_new_scb_done:
         clr     SCB_FIFO_USE_COUNT;
         /* Update the next SCB address to download. */
         bmov    NEXT_QUEUED_SCB_ADDR, SCB_NEXT_SCB_BUSADDR, 4;
+        /*
+         * NULL out the SCB links since these fields
+         * occupy the same location as SCB_NEXT_SCB_BUSADDR.
+         */
         mvi     SCB_NEXT[1], SCB_LIST_NULL;
         mvi     SCB_NEXT2[1], SCB_LIST_NULL;
         /* Increment our position in the QINFIFO. */
         mov     NONE, SNSCB_QOFF;
+
         /*
-         * SCBs that want to send messages are always
-         * queued independently.  This ensures that they
-         * are at the head of the SCB list to select out
-         * to a target and we will see the MK_MESSAGE flag.
+         * Save SCBID of this SCB in REG0 since
+         * SCBPTR will be clobbered during target
+         * list updates.  We also record the SCB's
+         * flags so that we can refer to them even
+         * after SCBPTR has been changed.
+         */
+        bmov    REG0, SCBPTR, 2;
+        mov     A, SCB_CONTROL;
+
+        /*
+         * Find the tail SCB of the execution queue
+         * for this target.
          */
-        test    SCB_CONTROL, MK_MESSAGE jnz first_new_target_scb;
         shr     SINDEX, 3, SCB_SCSIID;
         and     SINDEX, ~0x1;
         mvi     SINDEX[1], (WAITING_SCB_TAILS >> 8);
         bmov    DINDEX, SINDEX, 2;
         bmov    SCBPTR, SINDIR, 2;
+
+        /*
+         * Update the tail to point to the new SCB.
+         */
         bmov    DINDIR, REG0, 2;
+
+        /*
+         * If the queue was empty, queue this SCB as
+         * the first for this target.
+         */
         cmp     SCBPTR[1], SCB_LIST_NULL je first_new_target_scb;
+
+        /*
+         * SCBs that want to send messages must always be
+         * at the head of their per-target queue so that
+         * ATN can be asserted even if the current
+         * negotiation agreement is packetized.  If the
+         * target queue is empty, the SCB can be queued
+         * immediately.  If the queue is not empty, we must
+         * wait for it to empty before entering this SCB
+         * into the waiting for selection queue.  Otherwise
+         * our batching and round-robin selection scheme 
+         * could allow commands to be queued out of order.
+         * To simplify the implementation, we stop pulling
+         * new commands from the host until the MK_MESSAGE
+         * SCB can be queued to the waiting for selection
+         * list.
+         */
+        test    A, MK_MESSAGE jz batch_scb; 
+
+        /*
+         * If the last SCB is also a MK_MESSAGE SCB, then
+         * order is preserved even if we batch.
+         */
+        test    SCB_CONTROL, MK_MESSAGE jz batch_scb; 
+
+        /*
+         * Defer this SCB and stop fetching new SCBs until
+         * it can be queued.  Since the SCB_SCSIID of the
+         * tail SCB must be the same as that of the newly
+         * queued SCB, there is no need to restore the SCBID
+         * here.
+         */
+        or      SEQ_FLAGS2, PENDING_MK_MESSAGE;
+        bmov    MK_MESSAGE_SCB, REG0, 2;
+        mov     MK_MESSAGE_SCSIID, SCB_SCSIID ret;
+
+batch_scb:
+        /*
+         * Otherwise just update the previous tail SCB to
+         * point to the new tail.
+         */
         bmov    SCB_NEXT, REG0, 2 ret;
+
 first_new_target_scb:
+        /*
+         * Append SCB to the tail of the waiting for
+         * selection list.
+         */
         cmp     WAITING_TID_HEAD[1], SCB_LIST_NULL je first_new_scb;
         bmov    SCBPTR, WAITING_TID_TAIL, 2;
         bmov    SCB_NEXT2, REG0, 2;
         bmov    WAITING_TID_TAIL, REG0, 2 ret;
 first_new_scb:
+        /*
+         * Whole list is empty, so the head of
+         * the list must be initialized too.
+         */
         bmov    WAITING_TID_HEAD, REG0, 2;
         bmov    WAITING_TID_TAIL, REG0, 2 ret;
 END_CRITICAL;
 
 scbdma_idle:
         /*
-         * Give precedence to downloading new SCBs to execute
-         * unless select-outs are currently frozen.
+         * Don't bother downloading new SCBs to execute
+         * if select-outs are currently frozen or we have
+         * a MK_MESSAGE SCB waiting to enter the queue.
          */
-        test    SEQ_FLAGS2, SELECTOUT_QFROZEN jnz . + 2;
+        test    SEQ_FLAGS2, SELECTOUT_QFROZEN|PENDING_MK_MESSAGE
+                jnz scbdma_no_new_scbs;
 BEGIN_CRITICAL;
         test    QOFF_CTLSTA, NEW_SCB_AVAIL jnz fetch_new_scb;
+scbdma_no_new_scbs:
         cmp     COMPLETE_DMA_SCB_HEAD[1], SCB_LIST_NULL jne dma_complete_scb;
         cmp     COMPLETE_SCB_HEAD[1], SCB_LIST_NULL je return;
         /* FALLTHROUGH */
@@ -671,27 +742,41 @@ curscb_ww_done:
         }
 
         /*
-         * Requeue any SCBs not sent, to the tail of the waiting Q.
+         * The whole list made it.  Clear our tail pointer to indicate
+         * that the per-target selection queue is now empty.
          */
-        cmp     SCB_NEXT[1], SCB_LIST_NULL je select_out_list_done;
+        cmp     SCB_NEXT[1], SCB_LIST_NULL je select_out_clear_tail;
 
         /*
+         * Requeue any SCBs not sent, to the tail of the waiting Q.
          * We know that neither the per-TID list nor the list of
-         * TIDs is empty.  Use this knowledge to our advantage.
+         * TIDs is empty.  Use this knowledge to our advantage and
+         * queue the remainder to the tail of the global execution
+         * queue.
          */
         bmov    REG0, SCB_NEXT, 2;
+select_out_queue_remainder:
         bmov    SCBPTR, WAITING_TID_TAIL, 2;
         bmov    SCB_NEXT2, REG0, 2;
         bmov    WAITING_TID_TAIL, REG0, 2;
         jmp     select_out_inc_tid_q;
 
-select_out_list_done:
+select_out_clear_tail:
+        /*
+         * Queue any pending MK_MESSAGE SCB for this target now
+         * that the queue is empty.
+         */
+        test    SEQ_FLAGS2, PENDING_MK_MESSAGE jz select_out_no_mk_message_scb;
+        mov     A, MK_MESSAGE_SCSIID;
+        cmp     SCB_SCSIID, A jne select_out_no_mk_message_scb;
+        and     SEQ_FLAGS2, ~PENDING_MK_MESSAGE;
+        bmov    REG0, MK_MESSAGE_SCB, 2;
+        jmp select_out_queue_remainder;
+
+select_out_no_mk_message_scb:
         /*
-         * The whole list made it.  Just clear our TID's tail pointer
-         * unless we were queued independently due to our need to
-         * send a message.
+         * Clear this target's execution tail and increment the queue.
          */
-        test    SCB_CONTROL, MK_MESSAGE jnz select_out_inc_tid_q;
         shr     DINDEX, 3, SCB_SCSIID;
         or      DINDEX, 1;      /* Want only the second byte */
         mvi     DINDEX[1], ((WAITING_SCB_TAILS) >> 8);
@@ -703,8 +788,8 @@ select_out_inc_tid_q:
         mvi     WAITING_TID_TAIL[1], SCB_LIST_NULL;
         bmov    SCBPTR, CURRSCB, 2;
         mvi     CLRSINT0, CLRSELDO;
-        test    LQOSTAT2, LQOPHACHGOUTPKT jnz unexpected_nonpkt_phase;
-        test    LQOSTAT1, LQOPHACHGINPKT jnz unexpected_nonpkt_phase;
+        test    LQOSTAT2, LQOPHACHGOUTPKT jnz unexpected_nonpkt_mode_cleared;
+        test    LQOSTAT1, LQOPHACHGINPKT jnz unexpected_nonpkt_mode_cleared;
 
         /*
          * If this is a packetized connection, return to our
@@ -2127,6 +2212,18 @@ SET_DST_MODE	M_DFF0;
         mvi     DFFSXFRCTL, CLRCHN;
 unexpected_nonpkt_mode_cleared:
         mvi     CLRSINT2, CLRNONPACKREQ;
+        if ((ahd->bugs & AHD_BUSFREEREV_BUG) != 0) {
+                /*
+                 * Test to ensure that the bus has not
+                 * already gone free prior to clearing
+                 * any stale busfree status.  This avoids
+                 * a window whereby a busfree just after
+                 * a selection could be missed.
+                 */
+                test    SCSISIGI, BSYI jz . + 2;
+                mvi     CLRSINT1,CLRBUSFREE;
+                or      SIMODE1, ENBUSFREE;
+        }
         test    SCSIPHASE, ~(MSG_IN_PHASE|MSG_OUT_PHASE) jnz illegal_phase;
         SET_SEQINTCODE(ENTERING_NONPACK)
         jmp     ITloop;