[PATCH 0/2] dmaengine: Fix issues in Xilinx dpdma driver

[PATCH 0/2] dmaengine: Fix issues in Xilinx dpdma driver

[Laurent Pinchart]

Hello,

This small patch series fixes two issues I've experienced with the
Xilinx dpdma driver. There isn't much to summarize in the cover letter,
please see individual patches for details.

Laurent Pinchart (2):
  dmaengine: xilinx: dpdma: Fix descriptor issuing on video group
  dmaengine: xilinx: dpdma: Fix race condition in done IRQ

 drivers/dma/xilinx/xilinx_dpdma.c | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

-- 
Regards,

Laurent Pinchart

[PATCH 1/2] dmaengine: xilinx: dpdma: Fix descriptor issuing on video group

[Laurent Pinchart]

When multiple channels are part of a video group, the transfer is
triggered only when all channels in the group are ready. The logic to do
so is incorrect, as it causes the descriptors for all channels but the
last one in a group to not being pushed to the hardware. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/dma/xilinx/xilinx_dpdma.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
index 55df63dead8d..d504112c609e 100644
--- a/drivers/dma/xilinx/xilinx_dpdma.c
+++ b/drivers/dma/xilinx/xilinx_dpdma.c
@@ -839,6 +839,7 @@ static void xilinx_dpdma_chan_queue_transfer(struct xilinx_dpdma_chan *chan)
 	struct xilinx_dpdma_tx_desc *desc;
 	struct virt_dma_desc *vdesc;
 	u32 reg, channels;
+	bool first_frame;
 
 	lockdep_assert_held(&chan->lock);
 
@@ -852,14 +853,6 @@ static void xilinx_dpdma_chan_queue_transfer(struct xilinx_dpdma_chan *chan)
 		chan->running = true;
 	}
 
-	if (chan->video_group)
-		channels = xilinx_dpdma_chan_video_group_ready(chan);
-	else
-		channels = BIT(chan->id);
-
-	if (!channels)
-		return;
-
 	vdesc = vchan_next_desc(&chan->vchan);
 	if (!vdesc)
 		return;
@@ -884,13 +877,26 @@ static void xilinx_dpdma_chan_queue_transfer(struct xilinx_dpdma_chan *chan)
 			    FIELD_PREP(XILINX_DPDMA_CH_DESC_START_ADDRE_MASK,
 				       upper_32_bits(sw_desc->dma_addr)));
 
-	if (chan->first_frame)
+	first_frame = chan->first_frame;
+	chan->first_frame = false;
+
+	if (chan->video_group) {
+		channels = xilinx_dpdma_chan_video_group_ready(chan);
+		/*
+		 * Trigger the transfer only when all channels in the group are
+		 * ready.
+		 */
+		if (!channels)
+			return;
+	} else {
+		channels = BIT(chan->id);
+	}
+
+	if (first_frame)
 		reg = XILINX_DPDMA_GBL_TRIG_MASK(channels);
 	else
 		reg = XILINX_DPDMA_GBL_RETRIG_MASK(channels);
 
-	chan->first_frame = false;
-
 	dpdma_write(xdev->reg, XILINX_DPDMA_GBL, reg);
 }
 
-- 
Regards,

Laurent Pinchart

[PATCH 2/2] dmaengine: xilinx: dpdma: Fix race condition in done IRQ

[Laurent Pinchart]

The active descriptor pointer is accessed from different contexts,
including different interrupt handlers, and its access must be protected
by the channel's lock. This wasn't done in the done IRQ handler. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/dma/xilinx/xilinx_dpdma.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
index d504112c609e..70b29bd079c9 100644
--- a/drivers/dma/xilinx/xilinx_dpdma.c
+++ b/drivers/dma/xilinx/xilinx_dpdma.c
@@ -1048,13 +1048,14 @@ static int xilinx_dpdma_chan_stop(struct xilinx_dpdma_chan *chan)
  */
 static void xilinx_dpdma_chan_done_irq(struct xilinx_dpdma_chan *chan)
 {
-	struct xilinx_dpdma_tx_desc *active = chan->desc.active;
+	struct xilinx_dpdma_tx_desc *active;
 	unsigned long flags;
 
 	spin_lock_irqsave(&chan->lock, flags);
 
 	xilinx_dpdma_debugfs_desc_done_irq(chan);
 
+	active = chan->desc.active;
 	if (active)
 		vchan_cyclic_callback(&active->vdesc);
 	else
-- 
Regards,

Laurent Pinchart

Re: [PATCH 0/2] dmaengine: Fix issues in Xilinx dpdma driver

[Vinod Koul]

On 07-03-21, 06:06, Laurent Pinchart wrote:
> Hello,
> 
> This small patch series fixes two issues I've experienced with the
> Xilinx dpdma driver. There isn't much to summarize in the cover letter,
> please see individual patches for details.

Applied, thanks

-- 
~Vinod