atari_NCR5380: Refactor Falcon special cases

Make the atari_NCR5380.c core driver usable by sun3_scsi, mac_scsi and
others by moving some of the Falcon-specific code out of the core driver:
!IS_A_TT, atari_read_overruns and falcon_dont_release. Replace these with
hostdata variables and flags. FLAG_CHECK_LAST_BYTE_SENT is unused in
atari_NCR5380.c so don't set it.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

3 files changed, 31 insertions, 24 deletions

diff --git a/drivers/scsi/NCR5380.h b/drivers/scsi/NCR5380.h
index 11257784b2d7..7b1a0913d94c 100644
--- a/drivers/scsi/NCR5380.h
+++ b/drivers/scsi/NCR5380.h
@@ -241,6 +241,7 @@
 #define FLAG_NCR53C400                  4       /* NCR53c400 */
 #define FLAG_NO_PSEUDO_DMA              8       /* Inhibit DMA */
 #define FLAG_DTC3181E                   16      /* DTC3181E */
+#define FLAG_LATE_DMA_SETUP             32      /* Setup NCR before DMA H/W */
 
 #ifndef ASM
 struct NCR5380_hostdata {
@@ -269,6 +270,9 @@ struct NCR5380_hostdata {
         struct delayed_work coroutine;          /* our co-routine */
         struct scsi_eh_save ses;
         char info[256];
+        int read_overruns;                /* number of bytes to cut from a
+                                           * transfer to handle chip overruns */
+        int retain_dma_intr;
 #ifdef PSEUDO_DMA
         unsigned spin_max_r;
         unsigned spin_max_w;
diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c
index 75d34031c280..371ca14f08ea 100644
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -839,7 +839,7 @@ static int __init NCR5380_init(struct Scsi_Host *instance, int flags)
         hostdata->connected = NULL;
         hostdata->issue_queue = NULL;
         hostdata->disconnected_queue = NULL;
-        hostdata->flags = FLAG_CHECK_LAST_BYTE_SENT;
+        hostdata->flags = flags;
 
         if (!the_template) {
                 the_template = instance->hostt;
@@ -1054,7 +1054,7 @@ static void NCR5380_main(struct work_struct *work)
                                                 hostdata->issue_queue = NEXT(tmp);
                                         }
                                         SET_NEXT(tmp, NULL);
-                                        falcon_dont_release++;
+                                        hostdata->retain_dma_intr++;
 
                                         /* reenable interrupts after finding one */
                                         local_irq_restore(flags);
@@ -1082,7 +1082,7 @@ static void NCR5380_main(struct work_struct *work)
                                         cmd_get_tag(tmp, tmp->cmnd[0] != REQUEST_SENSE);
 #endif
                                         if (!NCR5380_select(instance, tmp)) {
-                                                falcon_dont_release--;
+                                                hostdata->retain_dma_intr--;
                                                 /* release if target did not response! */
                                                 falcon_release_lock_if_possible(hostdata);
                                                 break;
@@ -1094,7 +1094,7 @@ static void NCR5380_main(struct work_struct *work)
 #ifdef SUPPORT_TAGS
                                                 cmd_free_tag(tmp);
 #endif
-                                                falcon_dont_release--;
+                                                hostdata->retain_dma_intr--;
                                                 local_irq_restore(flags);
                                                 dprintk(NDEBUG_MAIN, "scsi%d: main(): select() failed, "
                                                             "returned to issue_queue\n", HOSTNO);
@@ -1151,7 +1151,7 @@ static void NCR5380_dma_complete(struct Scsi_Host *instance)
                 return;
         }
 
-        if (atari_read_overruns) {
+        if (hostdata->read_overruns) {
                 p = hostdata->connected->SCp.phase;
                 if (p & SR_IO) {
                         udelay(10);
@@ -1181,9 +1181,9 @@ static void NCR5380_dma_complete(struct Scsi_Host *instance)
         *data += transfered;
         *count -= transfered;
 
-        if (atari_read_overruns) {
+        if (hostdata->read_overruns) {
                 if ((NCR5380_read(STATUS_REG) & PHASE_MASK) == p && (p & SR_IO)) {
-                        cnt = toPIO = atari_read_overruns;
+                        cnt = toPIO = hostdata->read_overruns;
                         if (overrun) {
                                 dprintk(NDEBUG_DMA, "Got an input overrun, using saved byte\n");
                                 *(*data)++ = saved_data;
@@ -1838,8 +1838,8 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
                 return -1;
         }
 
-        if (atari_read_overruns && (p & SR_IO))
-                c -= atari_read_overruns;
+        if (hostdata->read_overruns && (p & SR_IO))
+                c -= hostdata->read_overruns;
 
         dprintk(NDEBUG_DMA, "scsi%d: initializing DMA for %s, %d bytes %s %p\n",
                    HOSTNO, (p & SR_IO) ? "reading" : "writing",
@@ -1851,7 +1851,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
         NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_ENABLE_EOP_INTR | MR_MONITOR_BSY);
 #endif /* def REAL_DMA  */
 
-        if (IS_A_TT()) {
+        if (!(hostdata->flags & FLAG_LATE_DMA_SETUP)) {
                 /* On the Medusa, it is a must to initialize the DMA before
                  * starting the NCR. This is also the cleaner way for the TT.
                  */
@@ -1869,7 +1869,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
                 NCR5380_write(START_DMA_SEND_REG, 0);
         }
 
-        if (!IS_A_TT()) {
+        if (hostdata->flags & FLAG_LATE_DMA_SETUP) {
                 /* On the Falcon, the DMA setup must be done after the last */
                 /* NCR access, else the DMA setup gets trashed!
                  */
@@ -2084,7 +2084,7 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
                                         /* Accept message by clearing ACK */
                                         NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                         /* ++guenther: possible race with Falcon locking */
-                                        falcon_dont_release++;
+                                        hostdata->retain_dma_intr++;
                                         hostdata->connected = NULL;
                                         dprintk(NDEBUG_QUEUES, "scsi%d: command for target %d, lun %llu "
                                                   "completed\n", HOSTNO, cmd->device->id, cmd->device->lun);
@@ -2167,7 +2167,7 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
                                         while ((NCR5380_read(STATUS_REG) & SR_BSY) && !hostdata->connected)
                                                 barrier();
 
-                                        falcon_dont_release--;
+                                        hostdata->retain_dma_intr--;
                                         /* ++roman: For Falcon SCSI, release the lock on the
                                          * ST-DMA here if no other commands are waiting on the
                                          * disconnected queue.
@@ -2474,7 +2474,7 @@ static void NCR5380_reselect(struct Scsi_Host *instance)
 #endif
                     ) {
                         /* ++guenther: prevent race with falcon_release_lock */
-                        falcon_dont_release++;
+                        hostdata->retain_dma_intr++;
                         if (prev) {
                                 REMOVE(prev, NEXT(prev), tmp, NEXT(tmp));
                                 SET_NEXT(prev, NEXT(tmp));
@@ -2512,7 +2512,7 @@ static void NCR5380_reselect(struct Scsi_Host *instance)
         hostdata->connected = tmp;
         dprintk(NDEBUG_RESELECTION, "scsi%d: nexus established, target = %d, lun = %llu, tag = %d\n",
                    HOSTNO, tmp->device->id, tmp->device->lun, tmp->tag);
-        falcon_dont_release--;
+        hostdata->retain_dma_intr--;
 }
 
 
diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c
index 78324e056d4c..70c662f9fee4 100644
--- a/drivers/scsi/atari_scsi.c
+++ b/drivers/scsi/atari_scsi.c
@@ -196,8 +196,6 @@ static char		*atari_dma_orig_addr;
 /* mask for address bits that can't be used with the ST-DMA */
 static unsigned long    atari_dma_stram_mask;
 #define STRAM_ADDR(a)   (((a) & atari_dma_stram_mask) == 0)
-/* number of bytes to cut from a transfer to handle NCR overruns */
-static int atari_read_overruns;
 #endif
 
 static int setup_can_queue = -1;
@@ -446,8 +444,6 @@ static void atari_scsi_fetch_restbytes(void)
 #endif /* REAL_DMA */
 
 
-static int falcon_dont_release = 0;
-
 /* This function releases the lock on the DMA chip if there is no
  * connected command and the disconnected queue is empty.
  */
@@ -464,7 +460,7 @@ static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
         if (!hostdata->disconnected_queue &&
             !hostdata->issue_queue &&
             !hostdata->connected &&
-            !falcon_dont_release &&
+            !hostdata->retain_dma_intr &&
             stdma_is_locked_by(scsi_falcon_intr))
                 stdma_release();
 
@@ -846,6 +842,7 @@ static int __init atari_scsi_probe(struct platform_device *pdev)
         struct Scsi_Host *instance;
         int error;
         struct resource *irq;
+        int host_flags = 0;
 
         irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
         if (!irq)
@@ -942,7 +939,9 @@ static int __init atari_scsi_probe(struct platform_device *pdev)
 
         instance->irq = irq->start;
 
-        NCR5380_init(instance, 0);
+        host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP;
+
+        NCR5380_init(instance, host_flags);
 
         if (IS_A_TT()) {
                 error = request_irq(instance->irq, scsi_tt_intr, 0,
@@ -965,12 +964,16 @@ static int __init atari_scsi_probe(struct platform_device *pdev)
                  *
                  * In principle it should be sufficient to do max. 1 byte with
                  * PIO, but there is another problem on the Medusa with the DMA
-                 * rest data register. So 'atari_read_overruns' is currently set
+                 * rest data register. So read_overruns is currently set
                  * to 4 to avoid having transfers that aren't a multiple of 4.
                  * If the rest data bug is fixed, this can be lowered to 1.
                  */
-                if (MACH_IS_MEDUSA)
-                        atari_read_overruns = 4;
+                if (MACH_IS_MEDUSA) {
+                        struct NCR5380_hostdata *hostdata =
+                                shost_priv(instance);
+
+                        hostdata->read_overruns = 4;
+                }
 #endif
         } else {
                 /* Nothing to do for the interrupt: the ST-DMA is initialized