Implement the device_synchronize() callback which wait until a dma
channel is stopped to provide a synchronization point.
This protects the driver from multiple race conditions when terminating
and freeing resources. E.g. the completion callback still running after
device_terminate_all() has completed.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
---
drivers/dma/sh/rcar-dmac.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 3038654f11b5c6ed..4b90deb40d559bed 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -1353,6 +1353,13 @@ static void rcar_dmac_issue_pending(struct dma_chan *chan)
spin_unlock_irqrestore(&rchan->lock, flags);
}
+static void rcar_dmac_device_synchronize(struct dma_chan *chan)
+{
+ struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+
+ synchronize_irq(rchan->irq);
+}
+
/* -----------------------------------------------------------------------------
* IRQ handling
*/
@@ -1834,6 +1841,7 @@ static int rcar_dmac_probe(struct platform_device *pdev)
engine->device_terminate_all = rcar_dmac_chan_terminate_all;
engine->device_tx_status = rcar_dmac_tx_status;
engine->device_issue_pending = rcar_dmac_issue_pending;
+ engine->device_synchronize = rcar_dmac_device_synchronize;
ret = dma_async_device_register(engine);
if (ret < 0)
--
2.12.0
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