[PATCH v1 4/5] dmaengine: dw: Reset DRAIN bit when resume the channel

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

For Intel iDMA 32-bit the channel can be drained on a suspend.
We need to reset the bit on the resume to return a status quo.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
 drivers/dma/dw/core.c   | 10 +++++-----
 drivers/dma/dw/dw.c     |  8 ++++++++
 drivers/dma/dw/idma32.c | 13 +++++++++++--
 drivers/dma/dw/regs.h   |  1 +
 4 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 711f4d19bbf1..092d642bec83 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -846,11 +846,11 @@ static int dwc_pause(struct dma_chan *chan)
 	return 0;
 }
 
-static inline void dwc_chan_resume(struct dw_dma_chan *dwc)
+static inline void dwc_chan_resume(struct dw_dma_chan *dwc, bool drain)
 {
-	u32 cfglo = channel_readl(dwc, CFG_LO);
+	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
 
-	channel_writel(dwc, CFG_LO, cfglo & ~DWC_CFGL_CH_SUSP);
+	dw->resume_chan(dwc, drain);
 
 	clear_bit(DW_DMA_IS_PAUSED, &dwc->flags);
 }
@@ -863,7 +863,7 @@ static int dwc_resume(struct dma_chan *chan)
 	spin_lock_irqsave(&dwc->lock, flags);
 
 	if (test_bit(DW_DMA_IS_PAUSED, &dwc->flags))
-		dwc_chan_resume(dwc);
+		dwc_chan_resume(dwc, false);
 
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
@@ -886,7 +886,7 @@ static int dwc_terminate_all(struct dma_chan *chan)
 
 	dwc_chan_disable(dw, dwc);
 
-	dwc_chan_resume(dwc);
+	dwc_chan_resume(dwc, true);
 
 	/* active_list entries will end up before queued entries */
 	list_splice_init(&dwc->queue, &list);
diff --git a/drivers/dma/dw/dw.c b/drivers/dma/dw/dw.c
index 998a9eeb561d..92f1e9c7b6f6 100644
--- a/drivers/dma/dw/dw.c
+++ b/drivers/dma/dw/dw.c
@@ -32,6 +32,13 @@ static void dw_dma_suspend_chan(struct dw_dma_chan *dwc, bool drain)
 	channel_writel(dwc, CFG_LO, cfglo | DWC_CFGL_CH_SUSP);
 }
 
+static void dw_dma_resume_chan(struct dw_dma_chan *dwc, bool drain)
+{
+	u32 cfglo = channel_readl(dwc, CFG_LO);
+
+	channel_writel(dwc, CFG_LO, cfglo & ~DWC_CFGL_CH_SUSP);
+}
+
 static u32 dw_dma_bytes2block(struct dw_dma_chan *dwc,
 			      size_t bytes, unsigned int width, size_t *len)
 {
@@ -88,6 +95,7 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 	/* Channel operations */
 	dw->initialize_chan = dw_dma_initialize_chan;
 	dw->suspend_chan = dw_dma_suspend_chan;
+	dw->resume_chan = dw_dma_resume_chan;
 	dw->encode_maxburst = dw_dma_encode_maxburst;
 	dw->bytes2block = dw_dma_bytes2block;
 	dw->block2bytes = dw_dma_block2bytes;
diff --git a/drivers/dma/dw/idma32.c b/drivers/dma/dw/idma32.c
index d06fb00fb862..7c013b257802 100644
--- a/drivers/dma/dw/idma32.c
+++ b/drivers/dma/dw/idma32.c
@@ -33,12 +33,20 @@ static void idma32_suspend_chan(struct dw_dma_chan *dwc, bool drain)
 
 	if (drain)
 		cfglo |= IDMA32C_CFGL_CH_DRAIN;
-	else
-		cfglo &= ~IDMA32C_CFGL_CH_DRAIN;
 
 	channel_writel(dwc, CFG_LO, cfglo | DWC_CFGL_CH_SUSP);
 }
 
+static void idma32_resume_chan(struct dw_dma_chan *dwc, bool drain)
+{
+	u32 cfglo = channel_readl(dwc, CFG_LO);
+
+	if (drain)
+		cfglo &= ~IDMA32C_CFGL_CH_DRAIN;
+
+	channel_writel(dwc, CFG_LO, cfglo & ~DWC_CFGL_CH_SUSP);
+}
+
 static u32 idma32_bytes2block(struct dw_dma_chan *dwc,
 			      size_t bytes, unsigned int width, size_t *len)
 {
@@ -116,6 +124,7 @@ int idma32_dma_probe(struct dw_dma_chip *chip)
 	/* Channel operations */
 	dw->initialize_chan = idma32_initialize_chan;
 	dw->suspend_chan = idma32_suspend_chan;
+	dw->resume_chan = idma32_resume_chan;
 	dw->encode_maxburst = idma32_encode_maxburst;
 	dw->bytes2block = idma32_bytes2block;
 	dw->block2bytes = idma32_block2bytes;
diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h
index 90e46e69c047..bd26c492507b 100644
--- a/drivers/dma/dw/regs.h
+++ b/drivers/dma/dw/regs.h
@@ -311,6 +311,7 @@ struct dw_dma {
 	/* Channel operations */
 	void	(*initialize_chan)(struct dw_dma_chan *dwc);
 	void	(*suspend_chan)(struct dw_dma_chan *dwc, bool drain);
+	void	(*resume_chan)(struct dw_dma_chan *dwc, bool drain);
 	void	(*encode_maxburst)(struct dw_dma_chan *dwc, u32 *maxburst);
 	u32	(*bytes2block)(struct dw_dma_chan *dwc, size_t bytes,
 			       unsigned int width, size_t *len);
-- 
2.19.2