dmaengine: stm32-dma3: add device_pause and device_resume ops

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 <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: ADESTM

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;