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Subject[ 28/37] sata_svw: check DMA start bit before reset
Date
3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Milburn <dmilburn@redhat.com>

commit b03e66a6be91f8389fcd902ab6c1563db1c9c06b upstream.

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>
Cc: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/ata/sata_svw.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)

--- a/drivers/ata/sata_svw.c
+++ b/drivers/ata/sata_svw.c
@@ -142,6 +142,39 @@ static int k2_sata_scr_write(struct ata_
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

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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