linux-kernel - [PATCH 4.4 40/42] dmaengine: pl330: Fix runtime PM support for terminated transfers

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Date:   Tue, 24 Jan 2017 08:55:50 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Vinod Koul <vinod.koul@...el.com>
Subject: [PATCH 4.4 40/42] dmaengine: pl330: Fix runtime PM support for terminated transfers

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

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

From: Marek Szyprowski <m.szyprowski@...sung.com>

commit 5c9e6c2b2ba3ec3a442e2fb5b4286498f8b4dcb7 upstream.

PL330 DMA engine driver is leaking a runtime reference after any terminated
DMA transactions. This patch fixes this issue by tracking runtime PM state
of the device and making additional call to pm_runtime_put() in terminate_all
callback if needed.

Fixes: ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12")
Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@...nel.org>
Signed-off-by: Vinod Koul <vinod.koul@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/dma/pl330.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -445,6 +445,9 @@ struct dma_pl330_chan {
 
 	/* for cyclic capability */
 	bool cyclic;
+
+	/* for runtime pm tracking */
+	bool active;
 };
 
 struct pl330_dmac {
@@ -1994,6 +1997,7 @@ static void pl330_tasklet(unsigned long
 		_stop(pch->thread);
 		spin_unlock(&pch->thread->dmac->lock);
 		power_down = true;
+		pch->active = false;
 	} else {
 		/* Make sure the PL330 Channel thread is active */
 		spin_lock(&pch->thread->dmac->lock);
@@ -2015,6 +2019,7 @@ static void pl330_tasklet(unsigned long
 			desc->status = PREP;
 			list_move_tail(&desc->node, &pch->work_list);
 			if (power_down) {
+				pch->active = true;
 				spin_lock(&pch->thread->dmac->lock);
 				_start(pch->thread);
 				spin_unlock(&pch->thread->dmac->lock);
@@ -2129,6 +2134,7 @@ static int pl330_terminate_all(struct dm
 	unsigned long flags;
 	struct pl330_dmac *pl330 = pch->dmac;
 	LIST_HEAD(list);
+	bool power_down = false;
 
 	pm_runtime_get_sync(pl330->ddma.dev);
 	spin_lock_irqsave(&pch->lock, flags);
@@ -2139,6 +2145,8 @@ static int pl330_terminate_all(struct dm
 	pch->thread->req[0].desc = NULL;
 	pch->thread->req[1].desc = NULL;
 	pch->thread->req_running = -1;
+	power_down = pch->active;
+	pch->active = false;
 
 	/* Mark all desc done */
 	list_for_each_entry(desc, &pch->submitted_list, node) {
@@ -2156,6 +2164,8 @@ static int pl330_terminate_all(struct dm
 	list_splice_tail_init(&pch->completed_list, &pl330->desc_pool);
 	spin_unlock_irqrestore(&pch->lock, flags);
 	pm_runtime_mark_last_busy(pl330->ddma.dev);
+	if (power_down)
+		pm_runtime_put_autosuspend(pl330->ddma.dev);
 	pm_runtime_put_autosuspend(pl330->ddma.dev);
 
 	return 0;
@@ -2302,6 +2312,7 @@ static void pl330_issue_pending(struct d
 		 * updated on work_list emptiness status.
 		 */
 		WARN_ON(list_empty(&pch->submitted_list));
+		pch->active = true;
 		pm_runtime_get_sync(pch->dmac->ddma.dev);
 	}
 	list_splice_tail_init(&pch->submitted_list, &pch->work_list);