ide: rework the code for selecting the best DMA transfer mode (v3)

Depends on the "ide: fix UDMA/MWDMA/SWDMA masks" patch.

* add ide_hwif_t.udma_filter hook for filtering UDMA mask
  (use it in alim15x3, hpt366, siimage and serverworks drivers)
* add ide_max_dma_mode() for finding best DMA mode for the device
  (loosely based on some older libata-core.c code)
* convert ide_dma_speed() users to use ide_max_dma_mode()
* make ide_rate_filter() take "ide_drive_t *drive" as an argument instead
  of "u8 mode" and teach it to how to use UDMA mask to do filtering
* use ide_rate_filter() in hpt366 driver
* remove no longer needed ide_dma_speed() and *_ratemask()
* unexport eighty_ninty_three()

v2:
* rename ->filter_udma_mask to ->udma_filter
  [ Suggested by Sergei Shtylyov <sshtylyov@ru.mvista.com>. ]

v3:
* updated for scc_pata driver (fixes XFER_UDMA_6 filtering for user-space
  originated transfer mode change requests when 100MHz clock is used)

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

1 files changed, 19 insertions, 12 deletions

diff --git a/drivers/ide/pci/serverworks.c b/drivers/ide/pci/serverworks.c
index dbcd37a0c652..2fa6d92d16cc 100644
--- a/drivers/ide/pci/serverworks.c
+++ b/drivers/ide/pci/serverworks.c
@@ -65,16 +65,16 @@ static int check_in_drive_lists (ide_drive_t *drive, const char **list)
         return 0;
 }
 
-static u8 svwks_ratemask (ide_drive_t *drive)
+static u8 svwks_udma_filter(ide_drive_t *drive)
 {
         struct pci_dev *dev     = HWIF(drive)->pci_dev;
-        u8 mode = 0;
+        u8 mask = 0;
 
         if (!svwks_revision)
                 pci_read_config_byte(dev, PCI_REVISION_ID, &svwks_revision);
 
         if (dev->device == PCI_DEVICE_ID_SERVERWORKS_HT1000IDE)
-                return 2;
+                return 0x1f;
         if (dev->device == PCI_DEVICE_ID_SERVERWORKS_OSB4IDE) {
                 u32 reg = 0;
                 if (isa_dev)
@@ -86,25 +86,31 @@ static u8 svwks_ratemask (ide_drive_t *drive)
                 if(drive->media == ide_disk)
                         return 0;
                 /* Check the OSB4 DMA33 enable bit */
-                return ((reg & 0x00004000) == 0x00004000) ? 1 : 0;
+                return ((reg & 0x00004000) == 0x00004000) ? 0x07 : 0;
         } else if (svwks_revision < SVWKS_CSB5_REVISION_NEW) {
-                return 1;
+                return 0x07;
         } else if (svwks_revision >= SVWKS_CSB5_REVISION_NEW) {
-                u8 btr = 0;
+                u8 btr = 0, mode;
                 pci_read_config_byte(dev, 0x5A, &btr);
                 mode = btr & 0x3;
-                if (!eighty_ninty_three(drive))
-                        mode = min(mode, (u8)1);
+
                 /* If someone decides to do UDMA133 on CSB5 the same
                    issue will bite so be inclusive */
                 if (mode > 2 && check_in_drive_lists(drive, svwks_bad_ata100))
                         mode = 2;
+
+                switch(mode) {
+                case 2:  mask = 0x1f; break;
+                case 1:  mask = 0x07; break;
+                default: mask = 0x00; break;
+                }
         }
         if (((dev->device == PCI_DEVICE_ID_SERVERWORKS_CSB6IDE) ||
              (dev->device == PCI_DEVICE_ID_SERVERWORKS_CSB6IDE2)) &&
             (!(PCI_FUNC(dev->devfn) & 1)))
-                mode = 2;
-        return mode;
+                mask = 0x1f;
+
+        return mask;
 }
 
 static u8 svwks_csb_check (struct pci_dev *dev)
@@ -141,7 +147,7 @@ static int svwks_tune_chipset (ide_drive_t *drive, u8 xferspeed)
         if (xferspeed == 255)   /* PIO auto-tuning */
                 speed = XFER_PIO_0 + pio;
         else
-                speed = ide_rate_filter(svwks_ratemask(drive), xferspeed);
+                speed = ide_rate_filter(drive, xferspeed);
 
         /* If we are about to put a disk into UDMA mode we screwed up.
            Our code assumes we never _ever_ do this on an OSB4 */
@@ -304,7 +310,7 @@ static void svwks_tune_drive (ide_drive_t *drive, u8 pio)
 
 static int config_chipset_for_dma (ide_drive_t *drive)
 {
-        u8 speed = ide_dma_speed(drive, svwks_ratemask(drive));
+        u8 speed = ide_max_dma_mode(drive);
 
         if (!(speed))
                 speed = XFER_PIO_0 + ide_get_best_pio_mode(drive, 255, 5, NULL);
@@ -500,6 +506,7 @@ static void __devinit init_hwif_svwks (ide_hwif_t *hwif)
 
         hwif->tuneproc = &svwks_tune_drive;
         hwif->speedproc = &svwks_tune_chipset;
+        hwif->udma_filter = &svwks_udma_filter;
 
         hwif->atapi_dma = 1;