[PATCH v3 3/5] dmaengine: sh: rz-dmac: Add device_{pause,resume}() callbacks

[Biju Das <biju.das.jz@xxxxxxxxxxxxxx>]

Add support for device_{pause, resume}() callbacks as it is needed
for RZ/G2L SCIFA driver.

Based on a patch in the BSP by Long Luu
<long.luu.ur@xxxxxxxxxxx>

Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
v2->v3:
 * No change.
v1->v2:
 * Added resume callback()
 * Updated commit description.
---
 drivers/dma/sh/rz-dmac.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index aaaae1c090ad..3ef516aee4fc 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -817,6 +817,35 @@ static enum dma_status rz_dmac_tx_status(struct dma_chan *chan,
 	return status;
 }
 
+static int rz_dmac_device_pause(struct dma_chan *chan)
+{
+	struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
+	struct rz_dmac *dmac = to_rz_dmac(chan->device);
+	unsigned int i;
+	u32 chstat;
+
+	for (i = 0; i < 1024; i++) {
+		chstat = rz_dmac_ch_readl(channel, CHSTAT, 1);
+		if (!(chstat & CHSTAT_EN))
+			break;
+		udelay(1);
+	}
+
+	rz_dmac_set_dmars_register(dmac, channel->index, 0);
+
+	return 0;
+}
+
+static int rz_dmac_device_resume(struct dma_chan *chan)
+{
+	struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
+	struct rz_dmac *dmac = to_rz_dmac(chan->device);
+
+	rz_dmac_set_dmars_register(dmac, channel->index, channel->mid_rid);
+
+	return 0;
+}
+
 /*
  * -----------------------------------------------------------------------------
  * IRQ handling
@@ -1106,6 +1135,8 @@ static int rz_dmac_probe(struct platform_device *pdev)
 	engine->device_terminate_all = rz_dmac_terminate_all;
 	engine->device_issue_pending = rz_dmac_issue_pending;
 	engine->device_synchronize = rz_dmac_device_synchronize;
+	engine->device_pause = rz_dmac_device_pause;
+	engine->device_resume = rz_dmac_device_resume;
 
 	engine->copy_align = DMAENGINE_ALIGN_1_BYTE;
 	dma_set_max_seg_size(engine->dev, U32_MAX);
-- 
2.25.1