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sata_svw: check DMA start bit before reset 

If kdump is triggered with pending IO, controller may not respond causing
kdump to fail.

http://marc.info/?l=linux-ide&m=133032255424658&w=2

During error recovery ata_do_dev_read_id never completes due hang
in mmio_insw.

ata_do_dev_read_id
 ata_sff_data_xfer
  ioread16_rep
   mmio_insw

if DMA start bit is cleared before reset, PIO command is successful
and kdump succeeds.

Signed-off-by: David Milburn <dmilburn@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
David Milburn 2012-10-29 18:00:22 -05:00 committed by Jeff Garzik
parent cd705d5ad4
commit b03e66a6be
1 changed files with 35 additions and 0 deletions
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35
drivers/ata/sata_svw.c
View File

@ -142,6 +142,39 @@ static int k2_sata_scr_write(struct ata_link *link,
return 0;
}
static int k2_sata_softreset(struct ata_link *link,
unsigned int *class, unsigned long deadline)
{
u8 dmactl;
void __iomem *mmio = link->ap->ioaddr.bmdma_addr;
dmactl = readb(mmio + ATA_DMA_CMD);
/* Clear the start bit */
if (dmactl & ATA_DMA_START) {
dmactl &= ~ATA_DMA_START;
writeb(dmactl, mmio + ATA_DMA_CMD);
}
return ata_sff_softreset(link, class, deadline);
}
static int k2_sata_hardreset(struct ata_link *link,
unsigned int *class, unsigned long deadline)
{
u8 dmactl;
void __iomem *mmio = link->ap->ioaddr.bmdma_addr;
dmactl = readb(mmio + ATA_DMA_CMD);
/* Clear the start bit */
if (dmactl & ATA_DMA_START) {
dmactl &= ~ATA_DMA_START;
writeb(dmactl, mmio + ATA_DMA_CMD);
}
return sata_sff_hardreset(link, class, deadline);
}
static void k2_sata_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)
{
@ -346,6 +379,8 @@ static struct scsi_host_template k2_sata_sht = {
static struct ata_port_operations k2_sata_ops = {
.inherits = &ata_bmdma_port_ops,
.softreset = k2_sata_softreset,
.hardreset = k2_sata_hardreset,
.sff_tf_load = k2_sata_tf_load,
.sff_tf_read = k2_sata_tf_read,
.sff_check_status = k2_stat_check_status,