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, 17 insertions, 59 deletions

diff --git a/drivers/ide/pci/alim15x3.c b/drivers/ide/pci/alim15x3.c
index 26c27d946c67..76643b626bdd 100644
--- a/drivers/ide/pci/alim15x3.c
+++ b/drivers/ide/pci/alim15x3.c
@@ -378,74 +378,31 @@ static void ali15x3_tune_drive (ide_drive_t *drive, u8 pio)
 }
 
 /**
- *	ali15x3_can_ultra	-	check for ultra DMA support
- *	@drive: drive to do the check
+ *	ali_udma_filter		-	compute UDMA mask
+ *	@drive: IDE device
  *
- *	Check the drive and controller revisions. Return 0 if UDMA is
- *	not available, or 1 if UDMA can be used. The actual rules for
- *	the ALi are
+ *	Return available UDMA modes.
+ *
+ *	The actual rules for the ALi are:
  *		No UDMA on revisions <= 0x20
  *		Disk only for revisions < 0xC2
  *		Not WDC drives for revisions < 0xC2
  *
  *	FIXME: WDC ifdef needs to die
  */
- 
-static u8 ali15x3_can_ultra (ide_drive_t *drive)
-{
-#ifndef CONFIG_WDC_ALI15X3
-	struct hd_driveid *id	= drive->id;
-#endif /* CONFIG_WDC_ALI15X3 */
-
-	if (m5229_revision <= 0x20) {
-		return 0;
-	} else if ((m5229_revision < 0xC2) &&
-#ifndef CONFIG_WDC_ALI15X3
-		   ((chip_is_1543c_e && strstr(id->model, "WDC ")) ||
-		    (drive->media!=ide_disk))) {
-#else /* CONFIG_WDC_ALI15X3 */
-		   (drive->media!=ide_disk)) {
-#endif /* CONFIG_WDC_ALI15X3 */
-		return 0;
-	} else {
-		return 1;
-	}
-}
 
-/**
- *	ali15x3_ratemask	-	generate DMA mode list
- *	@drive: drive to compute against
- *
- *	Generate a list of the available DMA modes for the drive. 
- *	FIXME: this function contains lots of bogus masking we can dump
- *
- *	Return the highest available mode (UDMA33, UDMA66, UDMA100,..)
- */
- 
-static u8 ali15x3_ratemask (ide_drive_t *drive)
+static u8 ali_udma_filter(ide_drive_t *drive)
 {
-	u8 mode = 0, can_ultra	= ali15x3_can_ultra(drive);
-
-	if (m5229_revision > 0xC4 && can_ultra) {
-		mode = 4;
-	} else if (m5229_revision == 0xC4 && can_ultra) {
-		mode = 3;
-	} else if (m5229_revision >= 0xC2 && can_ultra) {
-		mode = 2;
-	} else if (can_ultra) {
-		return 1;
-	} else {
-		return 0;
+	if (m5229_revision > 0x20 && m5229_revision < 0xC2) {
+		if (drive->media != ide_disk)
+			return 0;
+#ifndef CONFIG_WDC_ALI15X3
+		if (chip_is_1543c_e && strstr(drive->id->model, "WDC "))
+			return 0;
+#endif
 	}
 
-	/*
-	 *	If the drive sees no suitable cable then UDMA 33
-	 *	is the highest permitted mode
-	 */
-	 
-	if (!eighty_ninty_three(drive))
-		mode = min(mode, (u8)1);
-	return mode;
+	return drive->hwif->ultra_mask;
 }
 
 /**
@@ -461,7 +418,7 @@ static int ali15x3_tune_chipset (ide_drive_t *drive, u8 xferspeed)
 {
 	ide_hwif_t *hwif	= HWIF(drive);
 	struct pci_dev *dev	= hwif->pci_dev;
-	u8 speed		= ide_rate_filter(ali15x3_ratemask(drive), xferspeed);
+	u8 speed		= ide_rate_filter(drive, xferspeed);
 	u8 speed1		= speed;
 	u8 unit			= (drive->select.b.unit & 0x01);
 	u8 tmpbyte		= 0x00;
@@ -511,7 +468,7 @@ static int ali15x3_tune_chipset (ide_drive_t *drive, u8 xferspeed)
  
 static int config_chipset_for_dma (ide_drive_t *drive)
 {
-	u8 speed = ide_dma_speed(drive, ali15x3_ratemask(drive));
+	u8 speed = ide_max_dma_mode(drive);
 
 	if (!(speed))
 		return 0;
@@ -771,6 +728,7 @@ static void __devinit init_hwif_common_ali15x3 (ide_hwif_t *hwif)
 	hwif->autodma = 0;
 	hwif->tuneproc = &ali15x3_tune_drive;
 	hwif->speedproc = &ali15x3_tune_chipset;
+	hwif->udma_filter = &ali_udma_filter;
 
 	/* don't use LBA48 DMA on ALi devices before rev 0xC5 */
 	hwif->no_lba48_dma = (m5229_revision <= 0xC4) ? 1 : 0;