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>
b740d8846e