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 c0188de3cc6650..5314ec91372487 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;