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| author | Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> | 2010-02-13 14:35:53 +0100 |
|---|---|---|
| committer | Jeff Garzik <jgarzik@redhat.com> | 2010-03-01 20:58:46 +0100 |
| commit | a75032e8772d13dab5e3501413d7e14a148281b4 (patch) | |
| tree | 6ba3b740c6db7ef5056c3079d58fd96cedf4d790 /drivers/ata | |
| parent | [libata] pata_at91: fix backslash-continued string (diff) | |
| download | linux-a75032e8772d13dab5e3501413d7e14a148281b4.tar.xz linux-a75032e8772d13dab5e3501413d7e14a148281b4.zip | |
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>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers/ata')
| -rw-r--r-- | drivers/ata/pata_pdc202xx_old.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/ata/pata_pdc202xx_old.c b/drivers/ata/pata_pdc202xx_old.c index 2f3c9bed63d9..8d25bd59a16e 100644 --- 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 * @@ -35,6 +35,15 @@ static int pdc2026x_cable_detect(struct ata_port *ap) return ATA_CBL_PATA80; } +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); +} + /** * pdc202xx_configure_piomode - set chip PIO timing * @ap: ATA interface @@ -271,6 +280,8 @@ static struct ata_port_operations pdc2024x_port_ops = { .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 = { |