linux-kernel - [RESEND PATCH v5 2/7] dmaengine: hisilicon: Fix CQ head update

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Date:   Tue, 30 Aug 2022 14:22:46 +0800
From:   Jie Hai <haijie1@...wei.com>
To:     <vkoul@...nel.org>, <wangzhou1@...ilicon.com>
CC:     <dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [RESEND PATCH v5 2/7] dmaengine: hisilicon: Fix CQ head update

After completion of data transfer of one or multiple descriptors,
the completion status and the current head pointer to submission
queue are written into the CQ and interrupt can be generated to
inform the software. In interrupt process CQ is read and cq_head
is updated.

hisi_dma_irq updates cq_head only when the completion status is
success. When an abnormal interrupt reports, cq_head will not update
which will cause subsequent interrupt processes read the error CQ
and never report the correct status.

This patch updates cq_head whenever CQ is accessed.

Fixes: e9f08b65250d ("dmaengine: hisilicon: Add Kunpeng DMA engine support")
Signed-off-by: Jie Hai <haijie1@...wei.com>
Acked-by: Zhou Wang <wangzhou1@...ilicon.com>
---
 drivers/dma/hisi_dma.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/hisi_dma.c b/drivers/dma/hisi_dma.c
index 98bc488893cc..837f7e4adfa6 100644
--- a/drivers/dma/hisi_dma.c
+++ b/drivers/dma/hisi_dma.c
@@ -436,12 +436,10 @@ static irqreturn_t hisi_dma_irq(int irq, void *data)
 	desc = chan->desc;
 	cqe = chan->cq + chan->cq_head;
 	if (desc) {
+		chan->cq_head = (chan->cq_head + 1) % hdma_dev->chan_depth;
+		hisi_dma_chan_write(hdma_dev->base, HISI_DMA_CQ_HEAD_PTR,
+				    chan->qp_num, chan->cq_head);
 		if (FIELD_GET(STATUS_MASK, cqe->w0) == STATUS_SUCC) {
-			chan->cq_head = (chan->cq_head + 1) %
-					hdma_dev->chan_depth;
-			hisi_dma_chan_write(hdma_dev->base,
-					    HISI_DMA_CQ_HEAD_PTR, chan->qp_num,
-					    chan->cq_head);
 			vchan_cookie_complete(&desc->vd);
 		} else {
 			dev_err(&hdma_dev->pdev->dev, "task error!\n");
-- 
2.33.0