ncr5380: Merge DMA implementation from atari_NCR5380 core driver

Adopt the DMA implementation from atari_NCR5380.c. This means that
atari_scsi and sun3_scsi can make use of the NCR5380.c core driver
and the atari_NCR5380.c driver fork can be made redundant.

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>

13 files changed, 152 insertions, 40 deletions

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index e05cf505f0d4..fbd8a98af881 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -31,9 +31,6 @@
 
 /*
  * Further development / testing that should be done :
- * 1.  Cleanup the NCR5380_transfer_dma function and DMA operation complete
- * code so that everything does the same thing that's done at the
- * end of a pseudo-DMA read operation.
  *
  * 4.  Test SCSI-II tagged queueing (I have no devices which support
  * tagged queueing)
@@ -117,6 +114,8 @@
  *
  * PSEUDO_DMA - if defined, PSEUDO DMA is used during the data transfer phases.
  *
+ * REAL_DMA - if defined, REAL DMA is used during the data transfer phases.
+ *
  * These macros MUST be defined :
  *
  * NCR5380_read(register)  - read from the specified register
@@ -801,6 +800,72 @@ static void NCR5380_main(struct work_struct *work)
         } while (!done);
 }
 
+/*
+ * NCR5380_dma_complete - finish DMA transfer
+ * @instance: the scsi host instance
+ *
+ * Called by the interrupt handler when DMA finishes or a phase
+ * mismatch occurs (which would end the DMA transfer).
+ */
+
+static void NCR5380_dma_complete(struct Scsi_Host *instance)
+{
+        struct NCR5380_hostdata *hostdata = shost_priv(instance);
+        int transferred;
+        unsigned char **data;
+        int *count;
+        int saved_data = 0, overrun = 0;
+        unsigned char p;
+
+        if (hostdata->read_overruns) {
+                p = hostdata->connected->SCp.phase;
+                if (p & SR_IO) {
+                        udelay(10);
+                        if ((NCR5380_read(BUS_AND_STATUS_REG) &
+                             (BASR_PHASE_MATCH | BASR_ACK)) ==
+                            (BASR_PHASE_MATCH | BASR_ACK)) {
+                                saved_data = NCR5380_read(INPUT_DATA_REG);
+                                overrun = 1;
+                                dsprintk(NDEBUG_DMA, instance, "read overrun handled\n");
+                        }
+                }
+        }
+
+        NCR5380_write(MODE_REG, MR_BASE);
+        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
+        NCR5380_read(RESET_PARITY_INTERRUPT_REG);
+
+        transferred = hostdata->dma_len - NCR5380_dma_residual(instance);
+        hostdata->dma_len = 0;
+
+        data = (unsigned char **)&hostdata->connected->SCp.ptr;
+        count = &hostdata->connected->SCp.this_residual;
+        *data += transferred;
+        *count -= transferred;
+
+        if (hostdata->read_overruns) {
+                int cnt, toPIO;
+
+                if ((NCR5380_read(STATUS_REG) & PHASE_MASK) == p && (p & SR_IO)) {
+                        cnt = toPIO = hostdata->read_overruns;
+                        if (overrun) {
+                                dsprintk(NDEBUG_DMA, instance,
+                                         "Got an input overrun, using saved byte\n");
+                                *(*data)++ = saved_data;
+                                (*count)--;
+                                cnt--;
+                                toPIO--;
+                        }
+                        if (toPIO > 0) {
+                                dsprintk(NDEBUG_DMA, instance,
+                                         "Doing %d byte PIO to 0x%p\n", cnt, *data);
+                                NCR5380_transfer_pio(instance, &p, &cnt, data);
+                                *count -= toPIO - cnt;
+                        }
+                }
+        }
+}
+
 #ifndef DONT_USE_INTR
 
 /**
@@ -855,7 +920,22 @@ static irqreturn_t NCR5380_intr(int irq, void *dev_id)
                 dsprintk(NDEBUG_INTR, instance, "IRQ %d, BASR 0x%02x, SR 0x%02x, MR 0x%02x\n",
                          irq, basr, sr, mr);
 
-                if ((NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_mask) &&
+                if ((mr & MR_DMA_MODE) || (mr & MR_MONITOR_BSY)) {
+                        /* Probably End of DMA, Phase Mismatch or Loss of BSY.
+                         * We ack IRQ after clearing Mode Register. Workarounds
+                         * for End of DMA errata need to happen in DMA Mode.
+                         */
+
+                        dsprintk(NDEBUG_INTR, instance, "interrupt in DMA mode\n");
+
+                        if (hostdata->connected) {
+                                NCR5380_dma_complete(instance);
+                                queue_work(hostdata->work_q, &hostdata->main_task);
+                        } else {
+                                NCR5380_write(MODE_REG, MR_BASE);
+                                NCR5380_read(RESET_PARITY_INTERRUPT_REG);
+                        }
+                } else if ((NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_mask) &&
                     (sr & (SR_SEL | SR_IO | SR_BSY | SR_RST)) == (SR_SEL | SR_IO)) {
                         /* Probably reselected */
                         NCR5380_write(SELECT_ENABLE_REG, 0);
@@ -1431,28 +1511,38 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
         register unsigned char p = *phase;
         register unsigned char *d = *data;
         unsigned char tmp;
-        int result;
+        int result = 0;
 
         if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
                 *phase = tmp;
                 return -1;
         }
 
-        NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));
+        hostdata->connected->SCp.phase = p;
 
-        /*
-         * Note : on my sample board, watch-dog timeouts occurred when interrupts
-         * were not disabled for the duration of a single DMA transfer, from
-         * before the setting of DMA mode to after transfer of the last byte.
-         */
+        if (p & SR_IO) {
+                if (hostdata->read_overruns)
+                        c -= hostdata->read_overruns;
+                else if (hostdata->flags & FLAG_DMA_FIXUP)
+                        --c;
+        }
 
-        if (hostdata->flags & FLAG_DMA_FIXUP)
-                NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_MONITOR_BSY);
-        else
-                NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_MONITOR_BSY |
-                                        MR_ENABLE_EOP_INTR);
+        dsprintk(NDEBUG_DMA, instance, "initializing DMA %s: length %d, address %p\n",
+                 (p & SR_IO) ? "receive" : "send", c, d);
 
-        dprintk(NDEBUG_DMA, "scsi%d : mode reg = 0x%X\n", instance->host_no, NCR5380_read(MODE_REG));
+        NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));
+        NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_MONITOR_BSY |
+                                MR_ENABLE_EOP_INTR);
+
+        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.
+                 */
+                if (p & SR_IO)
+                        result = NCR5380_dma_recv_setup(instance, d, c);
+                else
+                        result = NCR5380_dma_send_setup(instance, d, c);
+        }
 
         /*
          * On the PAS16 at least I/O recovery delays are not needed here.
@@ -1470,6 +1560,29 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
                 NCR5380_io_delay(1);
         }
 
+        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!
+                 */
+                if (p & SR_IO)
+                        result = NCR5380_dma_recv_setup(instance, d, c);
+                else
+                        result = NCR5380_dma_send_setup(instance, d, c);
+        }
+
+        /* On failure, NCR5380_dma_xxxx_setup() returns a negative int. */
+        if (result < 0)
+                return result;
+
+        /* For real DMA, result is the byte count. DMA interrupt is expected. */
+        if (result > 0) {
+                hostdata->dma_len = result;
+                return 0;
+        }
+
+        /* The result is zero iff pseudo DMA send/receive was completed. */
+        hostdata->dma_len = c;
+
 /*
  * A note regarding the DMA errata workarounds for early NMOS silicon.
  *
@@ -1504,10 +1617,8 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
  * request.
  */
 
-        if (p & SR_IO) {
-                result = NCR5380_dma_recv_setup(instance, d,
-                        hostdata->flags & FLAG_DMA_FIXUP ? c - 1 : c);
-                if (!result && (hostdata->flags & FLAG_DMA_FIXUP)) {
+        if (hostdata->flags & FLAG_DMA_FIXUP) {
+                if (p & SR_IO) {
                         /*
                          * The workaround was to transfer fewer bytes than we
                          * intended to with the pseudo-DMA read function, wait for
@@ -1533,11 +1644,8 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
                                 result = -1;
                                 shost_printk(KERN_ERR, instance, "PDMA read: !REQ timeout\n");
                         }
-                        d[c - 1] = NCR5380_read(INPUT_DATA_REG);
-                }
-        } else {
-                result = NCR5380_dma_send_setup(instance, d, c);
-                if (!result && (hostdata->flags & FLAG_DMA_FIXUP)) {
+                        d[*count - 1] = NCR5380_read(INPUT_DATA_REG);
+                } else {
                         /*
                          * 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.
@@ -1550,11 +1658,8 @@ static int NCR5380_transfer_dma(struct Scsi_Host *instance,
                         }
                 }
         }
-        NCR5380_write(MODE_REG, MR_BASE);
-        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
-        NCR5380_read(RESET_PARITY_INTERRUPT_REG);
-        *data = d + c;
-        *count = 0;
+
+        NCR5380_dma_complete(instance);
         return result;
 }
 
@@ -1667,8 +1772,7 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
                                                 do_abort(instance);
                                                 cmd->result = DID_ERROR << 16;
                                                 /* XXX - need to source or sink data here, as appropriate */
-                                        } else
-                                                cmd->SCp.this_residual -= transfersize - len;
+                                        }
                                 } else {
                                         /* Break up transfer into 3 ms chunks,
                                          * presuming 6 accesses per handshake.
diff --git a/drivers/scsi/arm/cumana_1.c b/drivers/scsi/arm/cumana_1.c
index 402d984aa088..8e9cfe8f22f5 100644
--- a/drivers/scsi/arm/cumana_1.c
+++ b/drivers/scsi/arm/cumana_1.c
@@ -20,6 +20,7 @@
 #define NCR5380_dma_xfer_len(instance, cmd, phase)      (cmd->transfersize)
 #define NCR5380_dma_recv_setup          cumanascsi_pread
 #define NCR5380_dma_send_setup          cumanascsi_pwrite
+#define NCR5380_dma_residual(instance)  (0)
 
 #define NCR5380_intr                    cumanascsi_intr
 #define NCR5380_queue_command           cumanascsi_queue_command
@@ -245,7 +246,7 @@ static int cumanascsi1_probe(struct expansion_card *ec,
 
         host->irq = ec->irq;
 
-        ret = NCR5380_init(host, FLAG_DMA_FIXUP);
+        ret = NCR5380_init(host, FLAG_DMA_FIXUP | FLAG_LATE_DMA_SETUP);
         if (ret)
                 goto out_unmap;
 
diff --git a/drivers/scsi/arm/oak.c b/drivers/scsi/arm/oak.c
index 05cf874fc739..3aac99c21267 100644
--- a/drivers/scsi/arm/oak.c
+++ b/drivers/scsi/arm/oak.c
@@ -26,6 +26,7 @@
 #define NCR5380_dma_xfer_len(instance, cmd, phase)      (0)
 #define NCR5380_dma_recv_setup          oakscsi_pread
 #define NCR5380_dma_send_setup          oakscsi_pwrite
+#define NCR5380_dma_residual(instance)  (0)
 
 #define NCR5380_queue_command           oakscsi_queue_command
 #define NCR5380_info                    oakscsi_info
@@ -144,7 +145,7 @@ static int oakscsi_probe(struct expansion_card *ec, const struct ecard_id *id)
         host->irq = NO_IRQ;
         host->n_io_port = 255;
 
-        ret = NCR5380_init(host, FLAG_DMA_FIXUP);
+        ret = NCR5380_init(host, FLAG_DMA_FIXUP | FLAG_LATE_DMA_SETUP);
         if (ret)
                 goto out_unmap;
 
diff --git a/drivers/scsi/dmx3191d.c b/drivers/scsi/dmx3191d.c
index 4b58fa0c16fe..cc46d67b9f6f 100644
--- a/drivers/scsi/dmx3191d.c
+++ b/drivers/scsi/dmx3191d.c
@@ -42,6 +42,7 @@
 #define NCR5380_dma_xfer_len(instance, cmd, phase)      (0)
 #define NCR5380_dma_recv_setup(instance, dst, len)      (0)
 #define NCR5380_dma_send_setup(instance, src, len)      (0)
+#define NCR5380_dma_residual(instance)                  (0)
 
 #define NCR5380_implementation_fields   /* none */
 
diff --git a/drivers/scsi/dtc.c b/drivers/scsi/dtc.c
index df17904bbe12..e87c632234f3 100644
--- a/drivers/scsi/dtc.c
+++ b/drivers/scsi/dtc.c
@@ -228,7 +228,7 @@ found:
                 instance->base = addr;
                 ((struct NCR5380_hostdata *)(instance)->hostdata)->base = base;
 
-                if (NCR5380_init(instance, 0))
+                if (NCR5380_init(instance, FLAG_LATE_DMA_SETUP))
                         goto out_unregister;
 
                 NCR5380_maybe_reset_bus(instance);
diff --git a/drivers/scsi/dtc.h b/drivers/scsi/dtc.h
index 65af89e4340c..fcb0a8ea7bda 100644
--- a/drivers/scsi/dtc.h
+++ b/drivers/scsi/dtc.h
@@ -23,6 +23,7 @@
         dtc_dma_xfer_len(cmd)
 #define NCR5380_dma_recv_setup          dtc_pread
 #define NCR5380_dma_send_setup          dtc_pwrite
+#define NCR5380_dma_residual(instance)  (0)
 
 #define NCR5380_intr                    dtc_intr
 #define NCR5380_queue_command           dtc_queue_command
diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index f8c00c96a837..09e1cf938ecf 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -466,7 +466,7 @@ static int __init generic_NCR5380_detect(struct scsi_host_template *tpnt)
                 }
 #endif
 
-                if (NCR5380_init(instance, flags))
+                if (NCR5380_init(instance, flags | FLAG_LATE_DMA_SETUP))
                         goto out_unregister;
 
                 switch (overrides[current_override].board) {
diff --git a/drivers/scsi/g_NCR5380.h b/drivers/scsi/g_NCR5380.h
index 7f4308705532..595177428d76 100644
--- a/drivers/scsi/g_NCR5380.h
+++ b/drivers/scsi/g_NCR5380.h
@@ -64,6 +64,7 @@
         generic_NCR5380_dma_xfer_len(instance, cmd)
 #define NCR5380_dma_recv_setup          generic_NCR5380_pread
 #define NCR5380_dma_send_setup          generic_NCR5380_pwrite
+#define NCR5380_dma_residual(instance)  (0)
 
 #define NCR5380_intr generic_NCR5380_intr
 #define NCR5380_queue_command generic_NCR5380_queue_command
diff --git a/drivers/scsi/mac_scsi.c b/drivers/scsi/mac_scsi.c
index 99b7bbc3dd94..4de6589fdbfb 100644
--- a/drivers/scsi/mac_scsi.c
+++ b/drivers/scsi/mac_scsi.c
@@ -37,6 +37,7 @@
         macscsi_dma_xfer_len(instance, cmd)
 #define NCR5380_dma_recv_setup          macscsi_pread
 #define NCR5380_dma_send_setup          macscsi_pwrite
+#define NCR5380_dma_residual(instance)  (0)
 
 #define NCR5380_intr                    macscsi_intr
 #define NCR5380_queue_command           macscsi_queue_command
@@ -386,7 +387,7 @@ static int __init mac_scsi_probe(struct platform_device *pdev)
 #endif
         host_flags |= setup_toshiba_delay > 0 ? FLAG_TOSHIBA_DELAY : 0;
 
-        error = NCR5380_init(instance, host_flags);
+        error = NCR5380_init(instance, host_flags | FLAG_LATE_DMA_SETUP);
         if (error)
                 goto fail_init;
 
diff --git a/drivers/scsi/pas16.c b/drivers/scsi/pas16.c
index c8fd2230c792..62eef3f6d140 100644
--- a/drivers/scsi/pas16.c
+++ b/drivers/scsi/pas16.c
@@ -375,7 +375,7 @@ static int __init pas16_detect(struct scsi_host_template *tpnt)
                 
         instance->io_port = io_port;
 
-        if (NCR5380_init(instance, FLAG_DMA_FIXUP))
+        if (NCR5380_init(instance, FLAG_DMA_FIXUP | FLAG_LATE_DMA_SETUP))
                 goto out_unregister;
 
         NCR5380_maybe_reset_bus(instance);
diff --git a/drivers/scsi/pas16.h b/drivers/scsi/pas16.h
index f56f38796bcd..9fe7f33660b4 100644
--- a/drivers/scsi/pas16.h
+++ b/drivers/scsi/pas16.h
@@ -105,6 +105,7 @@
 #define NCR5380_dma_xfer_len(instance, cmd, phase)      (cmd->transfersize)
 #define NCR5380_dma_recv_setup          pas16_pread
 #define NCR5380_dma_send_setup          pas16_pwrite
+#define NCR5380_dma_residual(instance)  (0)
 
 #define NCR5380_intr pas16_intr
 #define NCR5380_queue_command pas16_queue_command
diff --git a/drivers/scsi/t128.c b/drivers/scsi/t128.c
index 6cc3da8d1d69..b5beecfaa3d5 100644
--- a/drivers/scsi/t128.c
+++ b/drivers/scsi/t128.c
@@ -208,7 +208,7 @@ found:
         instance->base = base;
         ((struct NCR5380_hostdata *)instance->hostdata)->base = p;
 
-        if (NCR5380_init(instance, FLAG_DMA_FIXUP))
+        if (NCR5380_init(instance, FLAG_DMA_FIXUP | FLAG_LATE_DMA_SETUP))
                 goto out_unregister;
 
         NCR5380_maybe_reset_bus(instance);
diff --git a/drivers/scsi/t128.h b/drivers/scsi/t128.h
index b6fe70f0aa4b..c95bcd839109 100644
--- a/drivers/scsi/t128.h
+++ b/drivers/scsi/t128.h
@@ -79,6 +79,7 @@
 #define NCR5380_dma_xfer_len(instance, cmd, phase)      (cmd->transfersize)
 #define NCR5380_dma_recv_setup          t128_pread
 #define NCR5380_dma_send_setup          t128_pwrite
+#define NCR5380_dma_residual(instance)  (0)
 
 #define NCR5380_intr t128_intr
 #define NCR5380_queue_command t128_queue_command