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 cf9d344d19f8..de5ad9c35dc6 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: