ide: remove ->ide_dma_check (take 2)

* Add IDE_HFLAG_TRUST_BIOS_FOR_DMA host flag for host drivers that depend
  on BIOS for programming device/controller for DMA.  Set it in cy82c693,
  generic, ns87415, opti621 and trm290 host drivers.

* Add IDE_HFLAG_VDMA host flag for host drivers using VDMA.  Set it in cs5520
  host driver.

* Teach ide_tune_dma() about IDE_HFLAG_TRUST_BIOS_FOR_DMA flag.

* Add generic ide_dma_check() helper and remove all open coded ->ide_dma_check
  implementations.  Fix all places checking for presence of ->ide_dma_check
  hook to check for ->ide_dma_on instead.

* Remove no longer needed code from config_drive_for_dma().

* Make ide_tune_dma() static.

v2:
* Fix config_drive_for_dma() return values.

* Fix ide-dma.c build for CONFIG_BLK_DEV_IDEDMA_PCI=n by adding
  dummy config_drive_for_dma() inline.

* Fix IDE_HFLAG_TRUST_BIOS_FOR_DMA handling in ide_dma_check().

* Fix init_hwif_it8213() comment.

There should be no functionality changes caused by this patch.

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

1 files changed, 45 insertions, 30 deletions

diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index a4cbbbaccde9..716a4fdcc0b5 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -338,35 +338,30 @@ static int config_drive_for_dma (ide_drive_t *drive)
         ide_hwif_t *hwif = drive->hwif;
         struct hd_driveid *id = drive->id;
 
-        /* consult the list of known "bad" drives */
-        if (__ide_dma_bad_drive(drive))
-                return -1;
-
         if (drive->media != ide_disk && hwif->atapi_dma == 0)
-                return -1;
+                return 0;
 
-        if ((id->capability & 1) && drive->autodma) {
-                /*
-                 * Enable DMA on any drive that has
-                 * UltraDMA (mode 0/1/2/3/4/5/6) enabled
-                 */
-                if ((id->field_valid & 4) && ((id->dma_ultra >> 8) & 0x7f))
-                        return 0;
-                /*
-                 * Enable DMA on any drive that has mode2 DMA
-                 * (multi or single) enabled
-                 */
-                if (id->field_valid & 2)        /* regular DMA */
-                        if ((id->dma_mword & 0x404) == 0x404 ||
-                            (id->dma_1word & 0x404) == 0x404)
-                                return 0;
-
-                /* Consult the list of known "good" drives */
-                if (ide_dma_good_drive(drive))
-                        return 0;
-        }
+        /*
+         * Enable DMA on any drive that has
+         * UltraDMA (mode 0/1/2/3/4/5/6) enabled
+         */
+        if ((id->field_valid & 4) && ((id->dma_ultra >> 8) & 0x7f))
+                return 1;
+
+        /*
+         * Enable DMA on any drive that has mode2 DMA
+         * (multi or single) enabled
+         */
+        if (id->field_valid & 2)        /* regular DMA */
+                if ((id->dma_mword & 0x404) == 0x404 ||
+                    (id->dma_1word & 0x404) == 0x404)
+                        return 1;
 
-        return -1;
+        /* Consult the list of known "good" drives */
+        if (ide_dma_good_drive(drive))
+                return 1;
+
+        return 0;
 }
 
 /**
@@ -627,6 +622,8 @@ static int __ide_dma_test_irq(ide_drive_t *drive)
                         drive->name, __FUNCTION__);
         return 0;
 }
+#else
+static inline int config_drive_for_dma(ide_drive_t *drive) { return 0; }
 #endif /* CONFIG_BLK_DEV_IDEDMA_PCI */
 
 int __ide_dma_bad_drive (ide_drive_t *drive)
@@ -758,7 +755,7 @@ u8 ide_find_dma_mode(ide_drive_t *drive, u8 req_mode)
 
 EXPORT_SYMBOL_GPL(ide_find_dma_mode);
 
-int ide_tune_dma(ide_drive_t *drive)
+static int ide_tune_dma(ide_drive_t *drive)
 {
         u8 speed;
 
@@ -769,6 +766,9 @@ int ide_tune_dma(ide_drive_t *drive)
         if (__ide_dma_bad_drive(drive))
                 return 0;
 
+        if (drive->hwif->host_flags & IDE_HFLAG_TRUST_BIOS_FOR_DMA)
+                return config_drive_for_dma(drive);
+
         speed = ide_max_dma_mode(drive);
 
         if (!speed)
@@ -785,6 +785,23 @@ int ide_tune_dma(ide_drive_t *drive)
 
 EXPORT_SYMBOL_GPL(ide_tune_dma);
 
+static int ide_dma_check(ide_drive_t *drive)
+{
+        ide_hwif_t *hwif = drive->hwif;
+        int vdma = (hwif->host_flags & IDE_HFLAG_VDMA)? 1 : 0;
+
+        if (!vdma && ide_tune_dma(drive))
+                return 0;
+
+        /* TODO: always do PIO fallback */
+        if (hwif->host_flags & IDE_HFLAG_TRUST_BIOS_FOR_DMA)
+                return -1;
+
+        ide_set_max_pio(drive);
+
+        return vdma ? 0 : -1;
+}
+
 void ide_dma_verbose(ide_drive_t *drive)
 {
         struct hd_driveid *id   = drive->id;
@@ -842,7 +859,7 @@ int ide_set_dma(ide_drive_t *drive)
         ide_hwif_t *hwif = drive->hwif;
         int rc;
 
-        rc = hwif->ide_dma_check(drive);
+        rc = ide_dma_check(drive);
 
         switch(rc) {
         case -1: /* DMA needs to be disabled */
@@ -1019,8 +1036,6 @@ void ide_setup_dma (ide_hwif_t *hwif, unsigned long dma_base, unsigned int num_p
                 hwif->ide_dma_on = &__ide_dma_on;
         if (!hwif->dma_host_on)
                 hwif->dma_host_on = &ide_dma_host_on;
-        if (!hwif->ide_dma_check)
-                hwif->ide_dma_check = &config_drive_for_dma;
         if (!hwif->dma_setup)
                 hwif->dma_setup = &ide_dma_setup;
         if (!hwif->dma_exec_cmd)