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authorBartlomiej Zolnierkiewicz <bzolnier@gmail.com>2010-02-13 14:35:53 +0100
committerJeff Garzik <jgarzik@redhat.com>2010-03-01 14:58:46 -0500
commita75032e8772d13dab5e3501413d7e14a148281b4 (patch)
tree6ba3b740c6db7ef5056c3079d58fd96cedf4d790 /drivers/ata
parent429e3861f9d5682c5bc5f237345f8962daf51bbc (diff)
downloadlinux-a75032e8772d13dab5e3501413d7e14a148281b4.tar.bz2
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.c13
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 = {