Re: [PATCH 13/15] ide: fix UDMA/MWDMA/SWDMA masks

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Alan wrote:
> > > >   Ugh, I'm not seeing any *actual* support for MW/SW DMA in this driver... 

> > > Thats long been broken. Should be correct in the libata driver

> >    Here's a surprise for you. pata_cmd64x copied the SW/MW DMA setup code 
> > from the IDE driver.  No way it could be working.  You may check against the 
> > PC64x datasheets (if you have them -- if you don't I think I may share) and 
> > see for yourself -- it's abolutely idiotic.

   I.e. MWDMA2 should be working due to the way the driver is written (it 
sets up PIO4 timings when auto-tuning DMA) but not the other modes since 
speedproc() method is brain-damaged in this part.

> Not a suprise to be honest. I fixed some of the ALi stuff when I did it
> and I think that was pushed back into drivers/ide. The CMD64x hasn't had
> much love really.

   Another buglet found by random glancing at this driver:

/**
 *      cmd648_dma_stop -       DMA stop callback
 *      @qc: Command in progress
 *
 *      DMA has completed.
 */

static void cmd648_bmdma_stop(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct pci_dev *pdev = to_pci_dev(ap->host->dev);
        u8 dma_intr;
        int dma_reg = ap->port_no ? ARTTIM23_INTR_CH1 : CFR_INTR_CH0;
        int dma_mask = ap->port_no ? ARTTIM2 : CFR;

        ata_bmdma_stop(qc);

        pci_read_config_byte(pdev, dma_reg, &dma_intr);
        pci_write_config_byte(pdev, dma_reg, dma_intr | dma_mask);
}

   dma_reg and dma_mask initializers must have been swapped since ARTTIM2 and 
CFR are regster names.  So, the code reads/writes semi-random regs...

> Wouldn't mind the older 64x (not 640) data sheets if they are sharable.

   Sent what I had on this machine.  Will looks for newer revision of 
PCJ0646U2 spec elsewhere...

MBR, Sergei
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