This is a note to let you know that I've just added the patch titled
dmaengine: at_xdmac: change block increment addressing mode
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dmaengine-at_xdmac-change-block-increment-addressing-mode.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a1cf09031e641d3cceaca4a4dd20ef6a785bc9b3 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Date: Tue, 15 Sep 2015 15:36:00 +0200
Subject: dmaengine: at_xdmac: change block increment addressing mode
From: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
commit a1cf09031e641d3cceaca4a4dd20ef6a785bc9b3 upstream.
The addressing mode we were using was not only incrementing the address at
each microblock, but also at each data boundary, which was severely slowing
the transfer, without any benefit since we were not using the data stride.
Switch to the micro block increment only in order to get back to an
acceptable performance level.
Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
Fixes: 6007ccb57744 ("dmaengine: xdmac: Add interleaved transfer support")
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/at_xdmac.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -878,14 +878,14 @@ at_xdmac_interleaved_queue_desc(struct d
if (xt->src_inc) {
if (xt->src_sgl)
- chan_cc |= AT_XDMAC_CC_SAM_UBS_DS_AM;
+ chan_cc |= AT_XDMAC_CC_SAM_UBS_AM;
else
chan_cc |= AT_XDMAC_CC_SAM_INCREMENTED_AM;
}
if (xt->dst_inc) {
if (xt->dst_sgl)
- chan_cc |= AT_XDMAC_CC_DAM_UBS_DS_AM;
+ chan_cc |= AT_XDMAC_CC_DAM_UBS_AM;
else
chan_cc |= AT_XDMAC_CC_DAM_INCREMENTED_AM;
}
Patches currently in stable-queue which might be from maxime.ripard@xxxxxxxxxxxxxxxxxx are
queue-4.2/dmaengine-at_xdmac-change-block-increment-addressing-mode.patch
queue-4.2/watchdog-sunxi-fix-activation-of-system-reset.patch
queue-4.2/arm-dts-sunxi-raise-minimum-cpu-voltage-for-sun7i-a20-to-meet-soc-specifications.patch
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