[PATCH v4 08/12] dmaengine: stm32-dma3: add device_pause and device_resume ops

[Amelie Delaunay]

STM32 DMA3 controller is able to suspend an ongoing transfer (the transfer
is suspended after the ongoing burst is flushed to the destination) and
resume it from the point it was suspended. No need to reconfigure any
register.

Signed-off-by: Amelie Delaunay <amelie.delaunay at foss.st.com>
---
 drivers/dma/stm32/stm32-dma3.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/dma/stm32/stm32-dma3.c b/drivers/dma/stm32/stm32-dma3.c
index 31c5b0e3fd18..5032d74d6288 100644
--- a/drivers/dma/stm32/stm32-dma3.c
+++ b/drivers/dma/stm32/stm32-dma3.c
@@ -1249,6 +1249,35 @@ static int stm32_dma3_config(struct dma_chan *c, struct dma_slave_config *config
 	return 0;
 }
 
+static int stm32_dma3_pause(struct dma_chan *c)
+{
+	struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
+	int ret;
+
+	ret = stm32_dma3_chan_suspend(chan, true);
+	if (ret)
+		return ret;
+
+	chan->dma_status = DMA_PAUSED;
+
+	dev_dbg(chan2dev(chan), "vchan %pK: paused\n", &chan->vchan);
+
+	return 0;
+}
+
+static int stm32_dma3_resume(struct dma_chan *c)
+{
+	struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
+
+	stm32_dma3_chan_suspend(chan, false);
+
+	chan->dma_status = DMA_IN_PROGRESS;
+
+	dev_dbg(chan2dev(chan), "vchan %pK: resumed\n", &chan->vchan);
+
+	return 0;
+}
+
 static int stm32_dma3_terminate_all(struct dma_chan *c)
 {
 	struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
@@ -1485,6 +1514,8 @@ static int stm32_dma3_probe(struct platform_device *pdev)
 	dma_dev->device_prep_dma_cyclic = stm32_dma3_prep_dma_cyclic;
 	dma_dev->device_caps = stm32_dma3_caps;
 	dma_dev->device_config = stm32_dma3_config;
+	dma_dev->device_pause = stm32_dma3_pause;
+	dma_dev->device_resume = stm32_dma3_resume;
 	dma_dev->device_terminate_all = stm32_dma3_terminate_all;
 	dma_dev->device_synchronize = stm32_dma3_synchronize;
 	dma_dev->device_tx_status = dma_cookie_status;
-- 
2.25.1