[PATCH 3.14 191/228] dma: mv_xor: Flush descriptors before activating a channel

From: Greg Kroah-Hartman
Date: Wed Jun 04 2014 - 20:03:35 EST


3.14-stable review patch. If anyone has any objections, please let me know.

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

From: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxx>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/dma/mv_xor.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -191,12 +191,10 @@ static void mv_set_mode(struct mv_xor_ch

static void mv_chan_activate(struct mv_xor_chan *chan)
{
- u32 activation;
-
dev_dbg(mv_chan_to_devp(chan), " activate chan.\n");
- activation = readl_relaxed(XOR_ACTIVATION(chan));
- activation |= 0x1;
- writel_relaxed(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)


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