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, 21 insertions, 24 deletions

diff --git a/drivers/ide/pci/siimage.c b/drivers/ide/pci/siimage.c
index c0188de3cc66..5314ec913724 100644
--- a/drivers/ide/pci/siimage.c
+++ b/drivers/ide/pci/siimage.c
@@ -122,45 +122,41 @@ static inline unsigned long siimage_seldev(ide_drive_t *drive, int r)
 }
 
 /**
- *      siimage_ratemask        -       Compute available modes
- *      @drive: IDE drive
+ *      sil_udma_filter         -       compute UDMA mask
+ *      @drive: IDE device
+ *
+ *      Compute the available UDMA speeds for the device on the interface.
  *
- *      Compute the available speeds for the devices on the interface.
  *      For the CMD680 this depends on the clocking mode (scsc), for the
- *      SI3312 SATA controller life is a bit simpler. Enforce UDMA33
- *      as a limit if there is no 80pin cable present.
+ *      SI3112 SATA controller life is a bit simpler.
  */
- 
-static byte siimage_ratemask (ide_drive_t *drive)
+
+static u8 sil_udma_filter(ide_drive_t *drive)
 {
-        ide_hwif_t *hwif        = HWIF(drive);
-        u8 mode = 0, scsc = 0;
+        ide_hwif_t *hwif = drive->hwif;
         unsigned long base = (unsigned long) hwif->hwif_data;
+        u8 mask = 0, scsc = 0;
 
         if (hwif->mmio)
                 scsc = hwif->INB(base + 0x4A);
         else
                 pci_read_config_byte(hwif->pci_dev, 0x8A, &scsc);
 
-        if(is_sata(hwif))
-        {
-                if(strstr(drive->id->model, "Maxtor"))
-                        return 3;
-                return 4;
+        if (is_sata(hwif)) {
+                mask = strstr(drive->id->model, "Maxtor") ? 0x3f : 0x7f;
+                goto out;
         }
-        
+
         if ((scsc & 0x30) == 0x10)      /* 133 */
-                mode = 4;
+                mask = 0x7f;
         else if ((scsc & 0x30) == 0x20) /* 2xPCI */
-                mode = 4;
+                mask = 0x7f;
         else if ((scsc & 0x30) == 0x00) /* 100 */
-                mode = 3;
+                mask = 0x3f;
         else    /* Disabled ? */
                 BUG();
-
-        if (!eighty_ninty_three(drive))
-                mode = min(mode, (u8)1);
-        return mode;
+out:
+        return mask;
 }
 
 /**
@@ -306,7 +302,7 @@ static int siimage_tune_chipset (ide_drive_t *drive, byte xferspeed)
         ide_hwif_t *hwif        = HWIF(drive);
         u16 ultra = 0, multi    = 0;
         u8 mode = 0, unit       = drive->select.b.unit;
-        u8 speed                = ide_rate_filter(siimage_ratemask(drive), xferspeed);
+        u8 speed                = ide_rate_filter(drive, xferspeed);
         unsigned long base      = (unsigned long)hwif->hwif_data;
         u8 scsc = 0, addr_mask  = ((hwif->channel) ?
                                     ((hwif->mmio) ? 0xF4 : 0x84) :
@@ -389,7 +385,7 @@ static int siimage_tune_chipset (ide_drive_t *drive, byte xferspeed)
  
 static int config_chipset_for_dma (ide_drive_t *drive)
 {
-        u8 speed        = ide_dma_speed(drive, siimage_ratemask(drive));
+        u8 speed = ide_max_dma_mode(drive);
 
         if (!speed)
                 return 0;
@@ -989,6 +985,7 @@ static void __devinit init_hwif_siimage(ide_hwif_t *hwif)
         hwif->tuneproc  = &siimage_tuneproc;
         hwif->reset_poll = &siimage_reset_poll;
         hwif->pre_reset = &siimage_pre_reset;
+        hwif->udma_filter = &sil_udma_filter;
 
         if(is_sata(hwif)) {
                 static int first = 1;