serverworks: always tune CSB6

Switch the driver to always program DMA/PIO timings and set device transfer
mode instead of trusting BIOS on CSB6 controllers (libata pata_serverworks.c
driver is also doing things this way and there were no problems reported so
far).  While doing conversion I noticed that the old code had many issues:

* the code was assuming that hwif->dma_status is always valid
  (which obviously isn't true if hwif->dma_base == NULL)

* value of "(ultra_timing >> (4*unit)) & ~(0xF0)" expression wasn't checked
  to fit into udma_modes[5]

* code validating DMA timings didn't validate corresponding PIO timings

* extra CSB5 PIO register wasn't validated et all

* hwif->ide_dma_off_quietly() is always called before ide_set_dma() (which in
  turn calls hwif->speedproc() method - svwks_tune_chipset() in this case)
  so the code depending on DMA capable bit of DMA status to be set was never
  executed (=> the code was never validating DMA timings despite actually
  enabling DMA if the PIO timings were OK!)

* on resume driver dependend entirely on BIOS to restore timings and set
  transfer mode on the device

While at it:

There is no need to read PIO/MWDMA timings now so don't do it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>

diff --git a/drivers/ide/pci/serverworks.c b/drivers/ide/pci/serverworks.c
index d9c4fd1..09a7aed 100644 (file)
--- a/drivers/ide/pci/serverworks.c
+++ b/drivers/ide/pci/serverworks.c
@@ -1,5 +1,5 @@
 /*
- * linux/drivers/ide/pci/serverworks.c         Version 0.11    Jun 2 2007
+ * linux/drivers/ide/pci/serverworks.c         Version 0.20    Jun 3 2007
  *
  * Copyright (C) 1998-2000 Michel Aubry
  * Copyright (C) 1998-2000 Andrzej Krzysztofowicz
@@ -151,84 +151,11 @@ static int svwks_tune_chipset (ide_drive_t *drive, u8 xferspeed)
        if(dev->device == PCI_DEVICE_ID_SERVERWORKS_OSB4 &&
                drive->media == ide_disk && speed >= XFER_UDMA_0)
                        BUG();
-                       
-       pci_read_config_byte(dev, drive_pci[drive->dn], &pio_timing);
-       pci_read_config_byte(dev, drive_pci2[drive->dn], &dma_timing);
+
        pci_read_config_byte(dev, (0x56|hwif->channel), &ultra_timing);
        pci_read_config_word(dev, 0x4A, &csb5_pio);
        pci_read_config_byte(dev, 0x54, &ultra_enable);
 
-       /* If we are in RAID mode (eg AMI MegaIDE) then we can't it
-          turns out trust the firmware configuration */
-
-       if ((dev->class >> 8) != PCI_CLASS_STORAGE_IDE)
-               goto oem_setup_failed;
-
-       /* Per Specified Design by OEM, and ASIC Architect */
-       if ((dev->device == PCI_DEVICE_ID_SERVERWORKS_CSB6IDE) ||
-           (dev->device == PCI_DEVICE_ID_SERVERWORKS_CSB6IDE2)) {
-               if (!drive->init_speed) {
-                       u8 dma_stat = inb(hwif->dma_status);
-
-                       if (((ultra_enable << (7-drive->dn) & 0x80) == 0x80) &&
-                           ((dma_stat & (1<<(5+unit))) == (1<<(5+unit)))) {
-                               drive->current_speed = drive->init_speed = XFER_UDMA_0 + udma_modes[(ultra_timing >> (4*unit)) & ~(0xF0)];
-                               return 0;
-                       } else if ((dma_timing) &&
-                                  ((dma_stat&(1<<(5+unit)))==(1<<(5+unit)))) {
-                               u8 dmaspeed;
-
-                               switch (dma_timing & 0x77) {
-                               case 0x20:
-                                       dmaspeed = XFER_MW_DMA_2;
-                                       break;
-                               case 0x21:
-                                       dmaspeed = XFER_MW_DMA_1;
-                                       break;
-                               case 0x77:
-                                       dmaspeed = XFER_MW_DMA_0;
-                                       break;
-                               default:
-                                       goto dma_pio;
-                               }
-
-                               drive->current_speed = drive->init_speed = dmaspeed;
-                               return 0;
-                       }
-dma_pio:
-                       if (pio_timing) {
-                               u8 piospeed;
-
-                               switch (pio_timing & 0x7f) {
-                               case 0x20:
-                                       piospeed = XFER_PIO_4;
-                                       break;
-                               case 0x22:
-                                       piospeed = XFER_PIO_3;
-                                       break;
-                               case 0x34:
-                                       piospeed = XFER_PIO_2;
-                                       break;
-                               case 0x47:
-                                       piospeed = XFER_PIO_1;
-                                       break;
-                               case 0x5d:
-                                       piospeed = XFER_PIO_0;
-                                       break;
-                               default:
-                                       goto oem_setup_failed;
-                               }
-
-                               drive->current_speed = drive->init_speed = piospeed;
-                               return 0;
-                       }
-               }
-       }
-
-oem_setup_failed:
-
-       pio_timing      = 0;
-       dma_timing      = 0;
        ultra_timing    &= ~(0x0F << (4*unit));
        ultra_enable    &= ~(0x01 << drive->dn);
        csb5_pio        &= ~(0x0F << (4*drive->dn));