| Message ID | 20100213133553.11564.95723.sendpatchset@localhost |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
On 02/13/2010 08:35 AM, Bartlomiej Zolnierkiewicz wrote: > From: Bartlomiej Zolnierkiewicz<bzolnier@gmail.com> > Subject: [PATCH] pata_pdc202xx_old: fix UDMA mode for Promise UDMA33 cards > > On Monday 04 January 2010 02:30:24 pm Russell King wrote: > >> Found the problem - getting rid of the read of the alt status register >> after the command has been written fixes the UDMA CRC errors on write: >> >> @@ -676,7 +676,8 @@ void ata_sff_exec_command(struct ata_port *ap, const struct >> ata_taskfile *tf) >> DPRINTK("ata%u: cmd 0x%X\n", ap->print_id, tf->command); >> >> iowrite8(tf->command, ap->ioaddr.command_addr); >> - ata_sff_pause(ap); >> + ndelay(400); >> +// ata_sff_pause(ap); >> } >> EXPORT_SYMBOL_GPL(ata_sff_exec_command); >> >> >> This rather makes sense. The PDC20247 handles the UDMA part of the >> protocol. It has no way to tell the PDC20246 to wait while it suspends >> UDMA, so that a normal register access can take place - the 246 ploughs >> on with the register access without any regard to the state of the 247. >> >> If the drive immediately starts the UDMA protocol after a write to the >> command register (as it probably will for the DMA WRITE command), then >> we'll be accessing the taskfile in the middle of the UDMA setup, which >> can't be good. It's certainly a violation of the ATA specs. > > Fix it by adding custom ->sff_exec_command method for UDMA33 chipsets. > > Debugged-by: Russell King<rmk@arm.linux.org.uk> > Signed-off-by: Bartlomiej Zolnierkiewicz<bzolnier@gmail.com> > --- > drivers/ata/pata_pdc202xx_old.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) applied -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: b/drivers/ata/pata_pdc202xx_old.c =================================================================== --- a/drivers/ata/pata_pdc202xx_old.c +++ b/drivers/ata/pata_pdc202xx_old.c @@ -2,7 +2,7 @@ * pata_pdc202xx_old.c - Promise PDC202xx PATA for new ATA layer * (C) 2005 Red Hat Inc * Alan Cox <alan@lxorguk.ukuu.org.uk> - * (C) 2007,2009 Bartlomiej Zolnierkiewicz + * (C) 2007,2009,2010 Bartlomiej Zolnierkiewicz * * Based in part on linux/drivers/ide/pci/pdc202xx_old.c * @@ -26,6 +26,15 @@ #include "pata_pdc202xx_old.h" +static void pdc20246_exec_command(struct ata_port *ap, + const struct ata_taskfile *tf) +{ + DPRINTK("ata%u: cmd 0x%X\n", ap->print_id, tf->command); + + iowrite8(tf->command, ap->ioaddr.command_addr); + ndelay(400); +} + /** * pdc2026x_bmdma_start - DMA engine begin * @qc: ATA command @@ -171,6 +180,8 @@ static struct ata_port_operations pdc202 .cable_detect = ata_cable_40wire, .set_piomode = pdc202xx_set_piomode, .set_dmamode = pdc202xx_set_dmamode, + + .sff_exec_command = pdc20246_exec_command, }; static struct ata_port_operations pdc2026x_port_ops = {