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, 35 insertions, 32 deletions

diff --git a/drivers/ide/pci/hpt366.c b/drivers/ide/pci/hpt366.c
index cf9d344d19f..de5ad9c35dc 100644
--- a/drivers/ide/pci/hpt366.c
+++ b/drivers/ide/pci/hpt366.c
@@ -514,43 +514,31 @@ static int check_in_drive_list(ide_drive_t *drive, const char **list)
 	return 0;
 }
 
-static u8 hpt3xx_ratemask(ide_drive_t *drive)
-{
-	struct hpt_info *info	= pci_get_drvdata(HWIF(drive)->pci_dev);
-	u8 mode			= info->max_mode;
-
-	if (!eighty_ninty_three(drive) && mode)
-		mode = min(mode, (u8)1);
-	return mode;
-}
-
 /*
  *	Note for the future; the SATA hpt37x we must set
  *	either PIO or UDMA modes 0,4,5
  */
- 
-static u8 hpt3xx_ratefilter(ide_drive_t *drive, u8 speed)
+
+static u8 hpt3xx_udma_filter(ide_drive_t *drive)
 {
 	struct hpt_info *info	= pci_get_drvdata(HWIF(drive)->pci_dev);
 	u8 chip_type		= info->chip_type;
-	u8 mode			= hpt3xx_ratemask(drive);
-
-	if (drive->media != ide_disk)
-		return min(speed, (u8)XFER_PIO_4);
+	u8 mode			= info->max_mode;
+	u8 mask;
 
 	switch (mode) {
 		case 0x04:
-			speed = min_t(u8, speed, XFER_UDMA_6);
+			mask = 0x7f;
 			break;
 		case 0x03:
-			speed = min_t(u8, speed, XFER_UDMA_5);
+			mask = 0x3f;
 			if (chip_type >= HPT374)
 				break;
 			if (!check_in_drive_list(drive, bad_ata100_5))
 				goto check_bad_ata33;
 			/* fall thru */
 		case 0x02:
-			speed = min_t(u8, speed, XFER_UDMA_4);
+			mask = 0x1f;
 
 			/*
 			 * CHECK ME, Does this need to be changed to HPT374 ??
@@ -561,13 +549,13 @@ static u8 hpt3xx_ratefilter(ide_drive_t *drive, u8 speed)
 			    !check_in_drive_list(drive, bad_ata66_4))
 				goto check_bad_ata33;
 
-			speed = min_t(u8, speed, XFER_UDMA_3);
+			mask = 0x0f;
 			if (HPT366_ALLOW_ATA66_3 &&
 			    !check_in_drive_list(drive, bad_ata66_3))
 				goto check_bad_ata33;
 			/* fall thru */
 		case 0x01:
-			speed = min_t(u8, speed, XFER_UDMA_2);
+			mask = 0x07;
 
 		check_bad_ata33:
 			if (chip_type >= HPT370A)
@@ -577,10 +565,10 @@ static u8 hpt3xx_ratefilter(ide_drive_t *drive, u8 speed)
 			/* fall thru */
 		case 0x00:
 		default:
-			speed = min_t(u8, speed, XFER_MW_DMA_2);
+			mask = 0x00;
 			break;
 	}
-	return speed;
+	return mask;
 }
 
 static u32 get_speed_setting(u8 speed, struct hpt_info *info)
@@ -608,12 +596,19 @@ static int hpt36x_tune_chipset(ide_drive_t *drive, u8 xferspeed)
 	ide_hwif_t *hwif	= HWIF(drive);
 	struct pci_dev  *dev	= hwif->pci_dev;
 	struct hpt_info	*info	= pci_get_drvdata(dev);
-	u8  speed		= hpt3xx_ratefilter(drive, xferspeed);
+	u8  speed		= ide_rate_filter(drive, xferspeed);
 	u8  itr_addr		= drive->dn ? 0x44 : 0x40;
-	u32 itr_mask		= speed < XFER_MW_DMA_0 ? 0x30070000 :
-				 (speed < XFER_UDMA_0   ? 0xc0070000 : 0xc03800ff);
-	u32 new_itr		= get_speed_setting(speed, info);
 	u32 old_itr		= 0;
+	u32 itr_mask, new_itr;
+
+	/* TODO: move this to ide_rate_filter() [ check ->atapi_dma ] */
+	if (drive->media != ide_disk)
+		speed = min_t(u8, speed, XFER_PIO_4);
+
+	itr_mask = speed < XFER_MW_DMA_0 ? 0x30070000 :
+		  (speed < XFER_UDMA_0   ? 0xc0070000 : 0xc03800ff);
+
+	new_itr = get_speed_setting(speed, info);
 
 	/*
 	 * Disable on-chip PIO FIFO/buffer (and PIO MST mode as well)
@@ -633,12 +628,19 @@ static int hpt37x_tune_chipset(ide_drive_t *drive, u8 xferspeed)
 	ide_hwif_t *hwif	= HWIF(drive);
 	struct pci_dev  *dev	= hwif->pci_dev;
 	struct hpt_info	*info	= pci_get_drvdata(dev);
-	u8  speed		= hpt3xx_ratefilter(drive, xferspeed);
+	u8  speed		= ide_rate_filter(drive, xferspeed);
 	u8  itr_addr		= 0x40 + (drive->dn * 4);
-	u32 itr_mask		= speed < XFER_MW_DMA_0 ? 0x303c0000 :
-				 (speed < XFER_UDMA_0   ? 0xc03c0000 : 0xc1c001ff);
-	u32 new_itr		= get_speed_setting(speed, info);
 	u32 old_itr		= 0;
+	u32 itr_mask, new_itr;
+
+	/* TODO: move this to ide_rate_filter() [ check ->atapi_dma ] */
+	if (drive->media != ide_disk)
+		speed = min_t(u8, speed, XFER_PIO_4);
+
+	itr_mask = speed < XFER_MW_DMA_0 ? 0x303c0000 :
+		  (speed < XFER_UDMA_0   ? 0xc03c0000 : 0xc1c001ff);
+
+	new_itr = get_speed_setting(speed, info);
 
 	pci_read_config_dword(dev, itr_addr, &old_itr);
 	new_itr = (new_itr & ~itr_mask) | (old_itr & itr_mask);
@@ -676,7 +678,7 @@ static void hpt3xx_tune_drive(ide_drive_t *drive, u8 pio)
  */
 static int config_chipset_for_dma(ide_drive_t *drive)
 {
-	u8 speed = ide_dma_speed(drive, hpt3xx_ratemask(drive));
+	u8 speed = ide_max_dma_mode(drive);
 
 	if (!speed)
 		return 0;
@@ -1271,6 +1273,7 @@ static void __devinit init_hwif_hpt366(ide_hwif_t *hwif)
 	hwif->intrproc			= &hpt3xx_intrproc;
 	hwif->maskproc			= &hpt3xx_maskproc;
 	hwif->busproc			= &hpt3xx_busproc;
+	hwif->udma_filter		= &hpt3xx_udma_filter;
 
 	/*
 	 * HPT3xxN chips have some complications: