linux-kernel - [PATCH v4 5/8] dmaengine: xilinx: xdma: Add error checking in xdma_channel

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Date:   Fri,  8 Dec 2023 14:49:26 +0100
From:   Jan Kuliga <jankul@...tek.krakow.pl>
To:     lizhi.hou@....com, brian.xu@....com, raj.kumar.rampelli@....com,
        vkoul@...nel.org, michal.simek@....com, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org, miquel.raynal@...tlin.com
Cc:     jankul@...tek.krakow.pl
Subject: [PATCH v4 5/8] dmaengine: xilinx: xdma: Add error checking in xdma_channel_isr()

Check and clear the status register value before proceeding any
further in xdma_channel_isr(). It is necessary to do it since the
interrupt may occur on any error condition enabled at the start of a
transfer.

Signed-off-by: Jan Kuliga <jankul@...tek.krakow.pl>
---
 drivers/dma/xilinx/xdma.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/xilinx/xdma.c b/drivers/dma/xilinx/xdma.c
index 521ba2a653b6..d1bc36133a45 100644
--- a/drivers/dma/xilinx/xdma.c
+++ b/drivers/dma/xilinx/xdma.c
@@ -812,21 +812,25 @@ static irqreturn_t xdma_channel_isr(int irq, void *dev_id)
 	desc = to_xdma_desc(vd);
 	xdev = xchan->xdev_hdl;

+	/* Clear-on-read the status register */
+	ret = regmap_read(xdev->rmap, xchan->base + XDMA_CHAN_STATUS_RC, &st);
+	if (ret)
+		goto out;
+
+	st &= XDMA_CHAN_STATUS_MASK;
+	if ((st & XDMA_CHAN_ERROR_MASK) ||
+		!(st & (CHAN_CTRL_IE_DESC_COMPLETED | CHAN_CTRL_IE_DESC_STOPPED))) {
+		xdma_err(xdev, "channel error, status register value: 0x%x", st);
+		goto out;
+	}
+
 	ret = regmap_read(xdev->rmap, xchan->base + XDMA_CHAN_COMPLETED_DESC,
-			  &complete_desc_num);
+							&complete_desc_num);
 	if (ret)
 		goto out;

 	if (desc->cyclic) {
 		desc->completed_desc_num = complete_desc_num;
-
-		ret = regmap_read(xdev->rmap, xchan->base + XDMA_CHAN_STATUS,
-				  &st);
-		if (ret)
-			goto out;
-
-		regmap_write(xdev->rmap, xchan->base + XDMA_CHAN_STATUS, st);
-
 		vchan_cyclic_callback(vd);
 	} else {
 		xchan->busy = false;
--
2.34.1