Patchwork [3.5.y.z,extended,stable] Patch "sata_svw: check DMA start bit before reset" has been added to staging queue

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Submitter Herton Ronaldo Krzesinski
Date Dec. 13, 2012, 4:46 a.m.
Message ID <1355373963-2986-1-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/205726/
State New
Headers show

Comments

Herton Ronaldo Krzesinski - Dec. 13, 2012, 4:46 a.m.
This is a note to let you know that I have just added a patch titled

    sata_svw: check DMA start bit before reset

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

From 32c3da87d03d47b50ce5580ca2a0898b6986606c Mon Sep 17 00:00:00 2001
From: David Milburn <dmilburn@redhat.com>
Date: Mon, 29 Oct 2012 18:00:22 -0500
Subject: [PATCH 07/20] sata_svw: check DMA start bit before reset

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>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 drivers/ata/sata_svw.c |   35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

--
1.7.9.5

Patch

diff --git a/drivers/ata/sata_svw.c b/drivers/ata/sata_svw.c
index c646118..833607f 100644
--- a/drivers/ata/sata_svw.c
+++ b/drivers/ata/sata_svw.c
@@ -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,