[3.11.y.z extended stable] Patch "dma: mv_xor: Flush descriptors before activating a channel" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    dma: mv_xor: Flush descriptors before activating a channel

to the linux-3.11.y-queue branch of the 3.11.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-3.11.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 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b22e7101ae6073ae67f87f917715e733e75a3491 Mon Sep 17 00:00:00 2001
From: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
Date: Wed, 21 May 2014 14:02:35 -0700
Subject: dma: mv_xor: Flush descriptors before activating a channel

commit 5a9a55bf9157d3490b0c8c4c81d4708602c26e07 upstream.

We need to use writel() instead of writel_relaxed() when starting
a channel, to ensure all the descriptors have been flushed before
the activation.

While at it, remove the unneeded read-modify-write and make the
code simpler.

Signed-off-by: Lior Amsalem <alior at marvell.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
Signed-off-by: Dan Williams <dan.j.williams at intel.com>
[bwh: Backported to 3.2: it was using __raw_readl() and __raw_writel()
 which are just as wrong]
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/dma/mv_xor.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
index 200f1a3c9a44..753796d6c017 100644
--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -198,12 +198,10 @@ static void mv_set_mode(struct mv_xor_chan *chan,

 static void mv_chan_activate(struct mv_xor_chan *chan)
 {
-	u32 activation;
-
 	dev_dbg(mv_chan_to_devp(chan), " activate chan.\n");
-	activation = __raw_readl(XOR_ACTIVATION(chan));
-	activation |= 0x1;
-	__raw_writel(activation, XOR_ACTIVATION(chan));
+
+	/* writel ensures all descriptors are flushed before activation */
+	writel(BIT(0), XOR_ACTIVATION(chan));
 }

 static char mv_chan_is_busy(struct mv_xor_chan *chan)
--
1.9.1