Patch "dmaengine: pl330: Fix hang on dmaengine_terminate_all on certain boards" has been added to the 4.0-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    dmaengine: pl330: Fix hang on dmaengine_terminate_all on certain boards

to the 4.0-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-pl330-fix-hang-on-dmaengine_terminate_all-on-certain-boards.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 81cc6edc08705ac0146fe6ac14a0982a31ce6f3d Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Date: Thu, 21 May 2015 09:34:09 +0900
Subject: dmaengine: pl330: Fix hang on dmaengine_terminate_all on certain boards

From: Krzysztof Kozlowski <k.kozlowski@samsung.com>

commit 81cc6edc08705ac0146fe6ac14a0982a31ce6f3d upstream.

The pl330 device could hang infinitely on certain boards when DMA
channels are terminated.

It was caused by lack of runtime resume when executing
pl330_terminate_all() which calls the _stop() function. _stop() accesses
device register and can loop infinitely while checking for device state.

The hang was confirmed by Dinh Nguyen on Altera SOCFPGA Cyclone V
board during boot. It can be also triggered with:

$ echo 1 > /sys/module/dmatest/parameters/iterations
$ echo dma1chan0 > /sys/module/dmatest/parameters/channel
$ echo 1 > /sys/module/dmatest/parameters/run
$ sleep 1
$ cat /sys/module/dmatest/parameters/run

Reported-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Fixes: ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12")
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/dma/pl330.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2127,6 +2127,7 @@ static int pl330_terminate_all(struct dm
 	struct pl330_dmac *pl330 = pch->dmac;
 	LIST_HEAD(list);
 
+	pm_runtime_get_sync(pl330->ddma.dev);
 	spin_lock_irqsave(&pch->lock, flags);
 	spin_lock(&pl330->lock);
 	_stop(pch->thread);
@@ -2151,6 +2152,8 @@ static int pl330_terminate_all(struct dm
 	list_splice_tail_init(&pch->work_list, &pl330->desc_pool);
 	list_splice_tail_init(&pch->completed_list, &pl330->desc_pool);
 	spin_unlock_irqrestore(&pch->lock, flags);
+	pm_runtime_mark_last_busy(pl330->ddma.dev);
+	pm_runtime_put_autosuspend(pl330->ddma.dev);
 
 	return 0;
 }


Patches currently in stable-queue which might be from k.kozlowski@samsung.com are

queue-4.0/dmaengine-fix-choppy-sound-because-of-unimplemented-resume.patch
queue-4.0/dmaengine-pl330-fix-hang-on-dmaengine_terminate_all-on-certain-boards.patch
queue-4.0/i2c-s3c2410-fix-oops-in-suspend-callback-for-non-dt.patch
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