Commit b03e66a6 authored by David Milburn's avatar David Milburn Committed by Jeff Garzik
Browse files

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: default avatarDavid Milburn <dmilburn@redhat.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent cd705d5a

drivers/ata/sata_svw.c

+35 −0
Original line number Diff line number Diff line
@@ -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,

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