diff mbox series

[v7,3/4] dmaengine: pl330: Store pointer to slave device

Message ID 1485340088-25481-4-git-send-email-m.szyprowski@samsung.com
State New
Headers show
Series DMA Engine: switch PL330 driver to non-irq-safe runtime PM | expand

Commit Message

Marek Szyprowski Jan. 25, 2017, 10:28 a.m. UTC 
Store the pointer to slave device, which requested our channel. It will be
later used to implement runtime PM of PL330 DMA controller. Although
DMA channels might be requested many times, each DMA peripheral channel is
physically dedicated only for specific hardware, so there should be only
one slave device for each channel.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

Acked-by: Arnd Bergmann <arnd@arndb.de>

---
 drivers/dma/pl330.c | 9 +++++++++
 1 file changed, 9 insertions(+)

-- 
1.9.1

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diff mbox series

Patch

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index b6b2cc912380..c77a3494659c 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -450,6 +450,7 @@  struct dma_pl330_chan {
 
 	/* for runtime pm tracking */
 	bool active;
+	struct device *slave;
 };
 
 struct pl330_dmac {
@@ -2093,6 +2094,14 @@  static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec,
 	if (chan_id >= pl330->num_peripherals)
 		return NULL;
 
+	if (!pl330->peripherals[chan_id].slave) {
+		pl330->peripherals[chan_id].slave = slave;
+	} else if (pl330->peripherals[chan_id].slave != slave) {
+		dev_err(pl330->ddma.dev,
+			"Can't use same channel with multiple slave devices!\n");
+		return NULL;
+	}
+
 	return dma_get_slave_channel(&pl330->peripherals[chan_id].chan);
 }