[PATCH 3.12 124/146] dma: mv_xor: Flush descriptors before activating a channel

Jiri Slaby
2014-06-09T09:31:07Z

From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>

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

===============

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@marvell.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 536dcb8ba5fd..dea771435a19 100644
--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -205,12 +205,10 @@ 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 = 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)
--
1.9.3