cs5530/sc1200: add ->udma_filter methods

CS5530/SC1200 specifies that two drives on the same cable cannot mix
UDMA/MDMA.  Add {cs5530,sc1200}_udma_filter() to handle this.  This also
makes it possible to remove open-coded best DMA mode selection and use
standard ide_use_dma()/ide_max_dma_mode() helpers.  While at it bump
version numbers.

There should be no functionality changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 35 insertions, 51 deletions

diff --git a/drivers/ide/pci/sc1200.c b/drivers/ide/pci/sc1200.c
index b5ae0c50e216..c0254b5e7d92 100644
--- a/drivers/ide/pci/sc1200.c
+++ b/drivers/ide/pci/sc1200.c
@@ -1,7 +1,9 @@
 /*
- * linux/drivers/ide/pci/sc1200.c               Version 0.91    28-Jan-2003
+ * linux/drivers/ide/pci/sc1200.c               Version 0.92    Mar 10 2007
  *
  * Copyright (C) 2000-2002              Mark Lord <mlord@pobox.com>
+ * Copyright (C)      2007              Bartlomiej Zolnierkiewicz
+ *
  * May be copied or modified under the terms of the GNU General Public License
  *
  * Development of this chipset driver was funded
@@ -93,57 +95,33 @@ static const unsigned int sc1200_pio_timings[4][5] =
  */
 //#define SC1200_BAD_PIO(timings) (((timings)&~0x80000000)==0x00009172)
 
-static int sc1200_autoselect_dma_mode (ide_drive_t *drive)
+/*
+ *      The SC1200 specifies that two drives sharing a cable cannot mix
+ *      UDMA/MDMA.  It has to be one or the other, for the pair, though
+ *      different timings can still be chosen for each drive.  We could
+ *      set the appropriate timing bits on the fly, but that might be
+ *      a bit confusing.  So, for now we statically handle this requirement
+ *      by looking at our mate drive to see what it is capable of, before
+ *      choosing a mode for our own drive.
+ */
+static u8 sc1200_udma_filter(ide_drive_t *drive)
 {
-        int                     udma_ok = 1, mode = 0;
-        ide_hwif_t              *hwif = HWIF(drive);
-        int                     unit = drive->select.b.unit;
-        ide_drive_t             *mate = &hwif->drives[unit^1];
-        struct hd_driveid       *id = drive->id;
-
-        /*
-         * The SC1200 specifies that two drives sharing a cable cannot
-         * mix UDMA/MDMA.  It has to be one or the other, for the pair,
-         * though different timings can still be chosen for each drive.
-         * We could set the appropriate timing bits on the fly,
-         * but that might be a bit confusing.  So, for now we statically
-         * handle this requirement by looking at our mate drive to see
-         * what it is capable of, before choosing a mode for our own drive.
-         */
-        if (mate->present) {
-                struct hd_driveid *mateid = mate->id;
-                if (mateid && (mateid->capability & 1) && !__ide_dma_bad_drive(mate)) {
-                        if ((mateid->field_valid & 4) && (mateid->dma_ultra & 7))
-                                udma_ok = 1;
-                        else if ((mateid->field_valid & 2) && (mateid->dma_mword & 7))
-                                udma_ok = 0;
-                        else
-                                udma_ok = 1;
-                }
-        }
-        /*
-         * Now see what the current drive is capable of,
-         * selecting UDMA only if the mate said it was ok.
-         */
-        if (id && (id->capability & 1) && hwif->autodma && !__ide_dma_bad_drive(drive)) {
-                if (udma_ok && (id->field_valid & 4) && (id->dma_ultra & 7)) {
-                        if      (id->dma_ultra & 4)
-                                mode = XFER_UDMA_2;
-                        else if (id->dma_ultra & 2)
-                                mode = XFER_UDMA_1;
-                        else if (id->dma_ultra & 1)
-                                mode = XFER_UDMA_0;
-                }
-                if (!mode && (id->field_valid & 2) && (id->dma_mword & 7)) {
-                        if      (id->dma_mword & 4)
-                                mode = XFER_MW_DMA_2;
-                        else if (id->dma_mword & 2)
-                                mode = XFER_MW_DMA_1;
-                        else if (id->dma_mword & 1)
-                                mode = XFER_MW_DMA_0;
-                }
+        ide_hwif_t *hwif = drive->hwif;
+        ide_drive_t *mate = &hwif->drives[(drive->dn & 1) ^ 1];
+        struct hd_driveid *mateid = mate->id;
+        u8 mask = hwif->ultra_mask;
+
+        if (mate->present == 0)
+                goto out;
+
+        if ((mateid->capability & 1) && __ide_dma_bad_drive(mate) == 0) {
+                if ((mateid->field_valid & 4) && (mateid->dma_ultra & 7))
+                        goto out;
+                if ((mateid->field_valid & 2) && (mateid->dma_mword & 7))
+                        mask = 0;
         }
-        return mode;
+out:
+        return mask;
 }
 
 /*
@@ -250,7 +228,12 @@ static int sc1200_config_dma2 (ide_drive_t *drive, int mode)
  */
 static int sc1200_config_dma (ide_drive_t *drive)
 {
-        return sc1200_config_dma2(drive, sc1200_autoselect_dma_mode(drive));
+        u8 mode = 0;
+
+        if (ide_use_dma(drive))
+                mode = ide_max_dma_mode(drive);
+
+        return sc1200_config_dma2(drive, mode);
 }
 
 
@@ -461,6 +444,7 @@ static void __devinit init_hwif_sc1200 (ide_hwif_t *hwif)
                 hwif->serialized = hwif->mate->serialized = 1;
         hwif->autodma = 0;
         if (hwif->dma_base) {
+                hwif->udma_filter = sc1200_udma_filter;
                 hwif->ide_dma_check = &sc1200_config_dma;
                 hwif->ide_dma_end   = &sc1200_ide_dma_end;
                 if (!noautodma)