Hi Krzysztof,
On 2016-12-23 03:33, Krzysztof Kozlowski wrote:
On Fri, Dec 16, 2016 at 11:39:11AM +0100, Marek Szyprowski wrote:
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@xxxxxxxxxxx>
---
drivers/dma/pl330.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 030fe05ed43b..9f3dbc8c63d2 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -448,6 +448,9 @@ struct dma_pl330_chan {
/* for cyclic capability */
bool cyclic;
+
+ /* for runtime pm tracking */
+ bool active;
};
struct pl330_dmac {
@@ -2031,6 +2034,7 @@ static void pl330_tasklet(unsigned long data)
_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);
@@ -2050,6 +2054,7 @@ static void pl330_tasklet(unsigned long data)
desc->status = PREP;
list_move_tail(&desc->node, &pch->work_list);
if (power_down) {
+ pch->active = true;
It's been a while since I was playign with the driver so I don't
remember everything... but I can't get the logic behind this.
The device is marked as inactive and scheduled to power down. But you
mark chanel as active.
Please look 3 lines further. The channel is started again (because this
is cyclic request), so setting active to true is justified. Even power_down
is then set to false.
Maybe it is correct but for me it is unreadable.
I understand that you wanted to mark the device as active at some point,
in case transfer was terminated?
Frankly, I have no idea how to explain it more clear. Cyclic transfers are
automatically restarted, so the above logic simply keeps pch->active in sync
with hardware operations.
Best regards,
Krzysztof
spin_lock(&pch->thread->dmac->lock);
_start(pch->thread);
spin_unlock(&pch->thread->dmac->lock);
@@ -2164,6 +2169,7 @@ static int pl330_terminate_all(struct dma_chan *chan)
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);
@@ -2174,6 +2180,8 @@ static int pl330_terminate_all(struct dma_chan *chan)
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) {
@@ -2191,6 +2199,8 @@ static int pl330_terminate_all(struct dma_chan *chan)
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;
@@ -2350,6 +2360,7 @@ static void pl330_issue_pending(struct dma_chan *chan)
* 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);
--
1.9.1
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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