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, 2 insertions, 18 deletions

diff --git a/drivers/ide/pci/cs5535.c b/drivers/ide/pci/cs5535.c
index 45f43efbf92c..66a101e470d0 100644
--- a/drivers/ide/pci/cs5535.c
+++ b/drivers/ide/pci/cs5535.c
@@ -127,20 +127,6 @@ static void cs5535_set_speed(ide_drive_t *drive, u8 speed)
         }
 }
 
-static u8 cs5535_ratemask(ide_drive_t *drive)
-{
-        /* eighty93 will return 1 if it's 80core and capable of
-        exceeding udma2, 0 otherwise. we need ratemask to set
-        the max speed and if we can > udma2 then we return 2
-        which selects speed_max as udma4 which is the 5535's max
-        speed, and 1 selects udma2 which is the max for 40c */
-        if (!eighty_ninty_three(drive))
-                return 1;
-
-        return 2;
-}
-
-
 /****
  *      cs5535_set_drive         -     Configure the drive to the new speed
  *      @drive: Drive to set up
@@ -151,7 +137,7 @@ static u8 cs5535_ratemask(ide_drive_t *drive)
  */
 static int cs5535_set_drive(ide_drive_t *drive, u8 speed)
 {
-        speed = ide_rate_filter(cs5535_ratemask(drive), speed);
+        speed = ide_rate_filter(drive, speed);
         ide_config_drive_speed(drive, speed);
         cs5535_set_speed(drive, speed);
 
@@ -180,9 +166,7 @@ static void cs5535_tuneproc(ide_drive_t *drive, u8 xferspeed)
 
 static int cs5535_config_drive_for_dma(ide_drive_t *drive)
 {
-        u8 speed;
-
-        speed = ide_dma_speed(drive, cs5535_ratemask(drive));
+        u8 speed = ide_max_dma_mode(drive);
 
         /* If no DMA speed was available then let dma_check hit pio */
         if (!speed) {