ncr5380: Adopt uniform DMA setup convention

Standardize the DMA setup hooks so that the DMA implementation in
atari_NCR5380.c can be reconciled with pseudo DMA implementation in
NCR5380.c.

Calls to NCR5380_dma_recv_setup() and NCR5380_dma_send_setup() return
a negative value on failure, zero on PDMA transfer success and a positive
byte count for DMA setup success.

This convention is not entirely new, but is now applied consistently.

Also remove a pointless Status Register access: the *phase assignment is
redundant because after NCR5380_transfer_dma() returns control to
NCR5380_information_transfer(), that routine then returns control
to NCR5380_main(), which means *phase is dead.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

4 files changed, 20 insertions, 18 deletions

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index b3e5b6b57d83..e05cf505f0d4 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -1431,7 +1431,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
         register unsigned char p = *phase;
         register unsigned char *d = *data;
         unsigned char tmp;
-        int foo;
+        int result;
 
         if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
                 *phase = tmp;
@@ -1505,9 +1505,9 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
  */
 
         if (p & SR_IO) {
-                foo = NCR5380_dma_recv_setup(instance, d,
+                result = NCR5380_dma_recv_setup(instance, d,
                         hostdata->flags & FLAG_DMA_FIXUP ? c - 1 : c);
-                if (!foo && (hostdata->flags & FLAG_DMA_FIXUP)) {
+                if (!result && (hostdata->flags & FLAG_DMA_FIXUP)) {
                         /*
                          * The workaround was to transfer fewer bytes than we
                          * intended to with the pseudo-DMA read function, wait for
@@ -1525,19 +1525,19 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
 
                         if (NCR5380_poll_politely(instance, BUS_AND_STATUS_REG,
                                                   BASR_DRQ, BASR_DRQ, HZ) < 0) {
-                                foo = -1;
+                                result = -1;
                                 shost_printk(KERN_ERR, instance, "PDMA read: DRQ timeout\n");
                         }
                         if (NCR5380_poll_politely(instance, STATUS_REG,
                                                   SR_REQ, 0, HZ) < 0) {
-                                foo = -1;
+                                result = -1;
                                 shost_printk(KERN_ERR, instance, "PDMA read: !REQ timeout\n");
                         }
                         d[c - 1] = NCR5380_read(INPUT_DATA_REG);
                 }
         } else {
-                foo = NCR5380_dma_send_setup(instance, d, c);
-                if (!foo && (hostdata->flags & FLAG_DMA_FIXUP)) {
+                result = NCR5380_dma_send_setup(instance, d, c);
+                if (!result && (hostdata->flags & FLAG_DMA_FIXUP)) {
                         /*
                          * Wait for the last byte to be sent.  If REQ is being asserted for
                          * the byte we're interested, we'll ACK it and it will go false.
@@ -1545,7 +1545,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
                         if (NCR5380_poll_politely2(instance,
                              BUS_AND_STATUS_REG, BASR_DRQ, BASR_DRQ,
                              BUS_AND_STATUS_REG, BASR_PHASE_MATCH, 0, HZ) < 0) {
-                                foo = -1;
+                                result = -1;
                                 shost_printk(KERN_ERR, instance, "PDMA write: DRQ and phase timeout\n");
                         }
                 }
@@ -1555,8 +1555,7 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
         NCR5380_read(RESET_PARITY_INTERRUPT_REG);
         *data = d + c;
         *count = 0;
-        *phase = NCR5380_read(STATUS_REG) & PHASE_MASK;
-        return foo;
+        return result;
 }
 
 /*
@@ -1652,7 +1651,7 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
                                 if (!cmd->device->borken)
                                         transfersize = NCR5380_dma_xfer_len(instance, cmd, phase);
 
-                                if (transfersize) {
+                                if (transfersize > 0) {
                                         len = transfersize;
                                         if (NCR5380_transfer_dma(instance, &phase,
                                             &len, (unsigned char **)&cmd->SCp.ptr)) {
diff --git a/drivers/scsi/arm/cumana_1.c b/drivers/scsi/arm/cumana_1.c
index 7bcb66893059..402d984aa088 100644
--- a/drivers/scsi/arm/cumana_1.c
+++ b/drivers/scsi/arm/cumana_1.c
@@ -101,7 +101,10 @@ static inline int cumanascsi_pwrite(struct Scsi_Host *host,
   }
 end:
   writeb(priv(host)->ctrl | 0x40, priv(host)->base + CTRL);
-  return len;
+
+        if (len)
+                return -1;
+        return 0;
 }
 
 static inline int cumanascsi_pread(struct Scsi_Host *host,
@@ -163,7 +166,10 @@ static inline int cumanascsi_pread(struct Scsi_Host *host,
   }
 end:
   writeb(priv(host)->ctrl | 0x40, priv(host)->base + CTRL);
-  return len;
+
+        if (len)
+                return -1;
+        return 0;
 }
 
 static unsigned char cumanascsi_read(struct Scsi_Host *host, unsigned int reg)
diff --git a/drivers/scsi/arm/oak.c b/drivers/scsi/arm/oak.c
index 5d6e0e590638..05cf874fc739 100644
--- a/drivers/scsi/arm/oak.c
+++ b/drivers/scsi/arm/oak.c
@@ -47,13 +47,13 @@ static inline int oakscsi_pwrite(struct Scsi_Host *instance,
   void __iomem *base = priv(instance)->base;
 
 printk("writing %p len %d\n",addr, len);
-  if(!len) return -1;
 
   while(1)
   {
     int status;
     while (((status = readw(base + STAT)) & 0x100)==0);
   }
+  return 0;
 }
 
 static inline int oakscsi_pread(struct Scsi_Host *instance,
@@ -74,7 +74,7 @@ printk("reading %p len %d\n", addr, len);
       if(status & 0x200 || !timeout)
       {
         printk("status = %08X\n", status);
-        return 1;
+        return -1;
       }
     }
 
diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c
index 41ddd95cebe6..5a81cec79a59 100644
--- a/drivers/scsi/atari_scsi.c
+++ b/drivers/scsi/atari_scsi.c
@@ -527,9 +527,6 @@ static unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance,
          */
         dma_cache_maintenance(addr, count, dir);
 
-        if (count == 0)
-                printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
-
         if (IS_A_TT()) {
                 tt_scsi_dma.dma_ctrl = dir;
                 SCSI_DMA_WRITE_P(dma_addr, addr);