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: default avatarBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Acked-by: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
parent 71d441dd
/*
* 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
......@@ -152,83 +152,10 @@ static int svwks_tune_chipset (ide_drive_t *drive, u8 xferspeed)
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));
......
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