ide: add ->dma_check method

* Add (an optional) ->dma_check method for checking if DMA can be
  used for a given command and fail DMA setup in ide_dma_prepare()
  if necessary.

* Convert alim15x3 and trm290 host drivers to use ->dma_check.

* Rename ali15x3_dma_setup() to ali_dma_check() while at it.

There should be no functional changes caused by this patch.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

3 files changed, 19 insertions, 12 deletions

diff --git a/drivers/ide/alim15x3.c b/drivers/ide/alim15x3.c
index d3faf0b97f42..537da1cde16d 100644
--- a/drivers/ide/alim15x3.c
+++ b/drivers/ide/alim15x3.c
@@ -189,20 +189,20 @@ static void ali_set_dma_mode(ide_drive_t *drive, const u8 speed)
 }
 
 /**
- *      ali15x3_dma_setup       -       begin a DMA phase
+ *      ali_dma_check   -       DMA check
  *      @drive: target device
  *      @cmd: command
  *
  *      Returns 1 if the DMA cannot be performed, zero on success.
  */
 
-static int ali15x3_dma_setup(ide_drive_t *drive, struct ide_cmd *cmd)
+static int ali_dma_check(ide_drive_t *drive, struct ide_cmd *cmd)
 {
         if (m5229_revision < 0xC2 && drive->media != ide_disk) {
                 if (cmd->tf_flags & IDE_TFLAG_WRITE)
                         return 1;       /* try PIO instead of DMA */
         }
-        return ide_dma_setup(drive, cmd);
+        return 0;
 }
 
 /**
@@ -503,11 +503,12 @@ static const struct ide_port_ops ali_port_ops = {
 
 static const struct ide_dma_ops ali_dma_ops = {
         .dma_host_set           = ide_dma_host_set,
-        .dma_setup              = ali15x3_dma_setup,
+        .dma_setup              = ide_dma_setup,
         .dma_start              = ide_dma_start,
         .dma_end                = ide_dma_end,
         .dma_test_irq           = ide_dma_test_irq,
         .dma_lost_irq           = ide_dma_lost_irq,
+        .dma_check              = ali_dma_check,
         .dma_timer_expiry       = ide_dma_sff_timer_expiry,
         .dma_sff_read_status    = ide_dma_sff_read_status,
 };
diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index cf5897f5533f..c0505e2dfc2e 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -566,9 +566,12 @@ EXPORT_SYMBOL_GPL(ide_allocate_dma_engine);
 
 int ide_dma_prepare(ide_drive_t *drive, struct ide_cmd *cmd)
 {
+        const struct ide_dma_ops *dma_ops = drive->hwif->dma_ops;
+
         if ((drive->dev_flags & IDE_DFLAG_USING_DMA) == 0 ||
+            (dma_ops->dma_check && dma_ops->dma_check(drive, cmd)) ||
             ide_build_sglist(drive, cmd) == 0 ||
-            drive->hwif->dma_ops->dma_setup(drive, cmd))
+            dma_ops->dma_setup(drive, cmd))
                 return 1;
         return 0;
 }
diff --git a/drivers/ide/trm290.c b/drivers/ide/trm290.c
index b91bb709af40..1076efd050dc 100644
--- a/drivers/ide/trm290.c
+++ b/drivers/ide/trm290.c
@@ -176,19 +176,21 @@ static void trm290_selectproc (ide_drive_t *drive)
         trm290_prepare_drive(drive, !!(drive->dev_flags & IDE_DFLAG_USING_DMA));
 }
 
-static int trm290_dma_setup(ide_drive_t *drive, struct ide_cmd *cmd)
+static int trm290_dma_check(ide_drive_t *drive, struct ide_cmd *cmd)
 {
-        ide_hwif_t *hwif = drive->hwif;
-        unsigned int count, rw;
-
         if (cmd->tf_flags & IDE_TFLAG_WRITE) {
 #ifdef TRM290_NO_DMA_WRITES
                 /* always use PIO for writes */
                 return 1;
 #endif
-                rw = 1;
-        } else
-                rw = 2;
+        }
+        return 0;
+}
+
+static int trm290_dma_setup(ide_drive_t *drive, struct ide_cmd *cmd)
+{
+        ide_hwif_t *hwif = drive->hwif;
+        unsigned int count, rw = (cmd->tf_flags & IDE_TFLAG_WRITE) ? 1 : 2;
 
         count = ide_build_dmatable(drive, cmd);
         if (count == 0) {
@@ -312,6 +314,7 @@ static struct ide_dma_ops trm290_dma_ops = {
         .dma_end                = trm290_dma_end,
         .dma_test_irq           = trm290_dma_test_irq,
         .dma_lost_irq           = ide_dma_lost_irq,
+        .dma_check              = trm290_dma_check,
 };
 
 static const struct ide_port_info trm290_chipset __devinitdata = {