serverworks: PIO mode setup fixes

* limit max PIO mode to PIO4, this driver doesn't support PIO5 and attempt
  to program PIO5 by svwks_tune_chipset() could result in incorrect PIO
  timings being programmed and possibly the data corruption (it seems that
  the minimum possible values were used but I lack the datasheets to be sure)

* select best PIO mode in svwks_tune_drive() and not in svwks_tune_chipset()
  when doing PIO autotuning (pio == 255)

* don't try to tune PIO in config_chipset_for_dma() as ide_dma_enable() could
  return 1 if DMA was previously enabled (svwks_config_drive_xfer_rate()
  takes care of PIO tuning if no suitable DMA mode is found)

* remove config_chipset_for_pio() and use svwks_tune_drive() instead,
  config_chipset_for_pio() contained numerous bugs when selecting PIO mode
  (luckily it was only used for devices limited to PIO by capabilities/BIOS):

  - it didn't check for validity of id->eide_pio_modes and id->eide_pio_iordy
    before using them

  - it tried to found out maximum PIO mode basing on minimum IORDY cycle time
    (moreover wrong cycle times were used for PIO0/1/5)

  - it was overriding PIO blacklist and conservative PIO "downgrade" done
    by ide_get_best_pio_mode()

  - if the max drive PIO was PIO5 then XFER_PIO_0/XFER_PIO_SLOW was selected
    (XFER_PIO_SLOW is not supported by svwks_tune_chipset() so the result
     was the same as if using XFER_PIO_5 => wrong PIO timings were set)

  - it was overriding drive->current_speed

* bump driver version

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 15 insertions, 53 deletions

diff --git a/drivers/ide/pci/serverworks.c b/drivers/ide/pci/serverworks.c
index 2fa6d92d16cc..a94e77d67db3 100644
--- a/drivers/ide/pci/serverworks.c
+++ b/drivers/ide/pci/serverworks.c
@@ -1,9 +1,10 @@
 /*
- * linux/drivers/ide/pci/serverworks.c          Version 0.8      25 Ebr 2003
+ * linux/drivers/ide/pci/serverworks.c          Version 0.9     Mar 4 2007
  *
  * Copyright (C) 1998-2000 Michel Aubry
  * Copyright (C) 1998-2000 Andrzej Krzysztofowicz
  * Copyright (C) 1998-2000 Andre Hedrick <andre@linux-ide.org>
+ * Copyright (C)      2007 Bartlomiej Zolnierkiewicz
  * Portions copyright (c) 2001 Sun Microsystems
  *
  *
@@ -136,19 +137,14 @@ static int svwks_tune_chipset (ide_drive_t *drive, u8 xferspeed)
 
         ide_hwif_t *hwif        = HWIF(drive);
         struct pci_dev *dev     = hwif->pci_dev;
-        u8 speed;
-        u8 pio                  = ide_get_best_pio_mode(drive, 255, 5, NULL);
+        u8 speed                = ide_rate_filter(drive, xferspeed);
+        u8 pio                  = ide_get_best_pio_mode(drive, 255, 4, NULL);
         u8 unit                 = (drive->select.b.unit & 0x01);
         u8 csb5                 = svwks_csb_check(dev);
         u8 ultra_enable         = 0, ultra_timing = 0;
         u8 dma_timing           = 0, pio_timing = 0;
         u16 csb5_pio            = 0;
 
-        if (xferspeed == 255)   /* PIO auto-tuning */
-                speed = XFER_PIO_0 + pio;
-        else
-                speed = ide_rate_filter(drive, xferspeed);
-
         /* If we are about to put a disk into UDMA mode we screwed up.
            Our code assumes we never _ever_ do this on an OSB4 */
            
@@ -231,6 +227,9 @@ oem_setup_failed:
                 case XFER_MW_DMA_2:
                 case XFER_MW_DMA_1:
                 case XFER_MW_DMA_0:
+                        /*
+                         * TODO: always setup PIO mode so this won't be needed
+                         */
                         pio_timing |= pio_modes[pio];
                         csb5_pio   |= (pio << (4*drive->dn));
                         dma_timing |= dma_modes[speed - XFER_MW_DMA_0];
@@ -242,6 +241,9 @@ oem_setup_failed:
                 case XFER_UDMA_2:
                 case XFER_UDMA_1:
                 case XFER_UDMA_0:
+                        /*
+                         * TODO: always setup PIO mode so this won't be needed
+                         */
                         pio_timing   |= pio_modes[pio];
                         csb5_pio     |= (pio << (4*drive->dn));
                         dma_timing   |= dma_modes[2];
@@ -262,58 +264,18 @@ oem_setup_failed:
         return (ide_config_drive_speed(drive, speed));
 }
 
-static void config_chipset_for_pio (ide_drive_t *drive)
-{
-        u16 eide_pio_timing[6] = {960, 480, 240, 180, 120, 90};
-        u16 xfer_pio = drive->id->eide_pio_modes;
-        u8 timing, speed, pio;
-
-        pio = ide_get_best_pio_mode(drive, 255, 5, NULL);
-
-        if (xfer_pio > 4)
-                xfer_pio = 0;
-
-        if (drive->id->eide_pio_iordy > 0)
-                for (xfer_pio = 5;
-                        xfer_pio>0 &&
-                        drive->id->eide_pio_iordy>eide_pio_timing[xfer_pio];
-                        xfer_pio--);
-        else
-                xfer_pio = (drive->id->eide_pio_modes & 4) ? 0x05 :
-                           (drive->id->eide_pio_modes & 2) ? 0x04 :
-                           (drive->id->eide_pio_modes & 1) ? 0x03 :
-                           (drive->id->tPIO & 2) ? 0x02 :
-                           (drive->id->tPIO & 1) ? 0x01 : xfer_pio;
-
-        timing = (xfer_pio >= pio) ? xfer_pio : pio;
-
-        switch(timing) {
-                case 4: speed = XFER_PIO_4;break;
-                case 3: speed = XFER_PIO_3;break;
-                case 2: speed = XFER_PIO_2;break;
-                case 1: speed = XFER_PIO_1;break;
-                default:
-                        speed = (!drive->id->tPIO) ? XFER_PIO_0 : XFER_PIO_SLOW;
-                        break;
-        }
-        (void) svwks_tune_chipset(drive, speed);
-        drive->current_speed = speed;
-}
-
 static void svwks_tune_drive (ide_drive_t *drive, u8 pio)
 {
-        if(pio == 255)
-                (void) svwks_tune_chipset(drive, 255);
-        else
-                (void) svwks_tune_chipset(drive, (XFER_PIO_0 + pio));
+        pio = ide_get_best_pio_mode(drive, pio, 4, NULL);
+        (void)svwks_tune_chipset(drive, XFER_PIO_0 + pio);
 }
 
 static int config_chipset_for_dma (ide_drive_t *drive)
 {
         u8 speed = ide_max_dma_mode(drive);
 
-        if (!(speed))
-                speed = XFER_PIO_0 + ide_get_best_pio_mode(drive, 255, 5, NULL);
+        if (!speed)
+                return 0;
 
         (void) svwks_tune_chipset(drive, speed);
         return ide_dma_enable(drive);
@@ -327,7 +289,7 @@ static int svwks_config_drive_xfer_rate (ide_drive_t *drive)
                 return 0;
 
         if (ide_use_fast_pio(drive))
-                config_chipset_for_pio(drive);
+                svwks_tune_drive(drive, 255);
 
         return -1;
 }