linux-kernel - [PATCH] dmaengine: qcom_hidma: prevent disable in error

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Message-Id: <1475782394-27887-1-git-send-email-okaya@codeaurora.org>
Date:   Thu,  6 Oct 2016 15:33:14 -0400
From:   Sinan Kaya <okaya@...eaurora.org>
To:     dmaengine@...r.kernel.org, timur@...eaurora.org, cov@...eaurora.org
Cc:     linux-arm-msm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Sinan Kaya <okaya@...eaurora.org>, linux-kernel@...r.kernel.org
Subject: [PATCH] dmaengine: qcom_hidma: prevent disable in error

When an error is observed, we try to disable the channel and prevent
further accesses from the client.

Depending on the type of error, transitioning into disabled state might
not be possible. Adding a check to make sure that HW is in enabled/running
state before the disable transition happens.

Signed-off-by: Sinan Kaya <okaya@...eaurora.org>
---
 drivers/dma/qcom/hidma_ll.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/drivers/dma/qcom/hidma_ll.c b/drivers/dma/qcom/hidma_ll.c
index 3224f24..c3a66c9 100644
--- a/drivers/dma/qcom/hidma_ll.c
+++ b/drivers/dma/qcom/hidma_ll.c
@@ -564,19 +564,8 @@ int hidma_ll_disable(struct hidma_lldev *lldev)
 	u32 val;
 	int ret;
 
-	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
-	lldev->evch_state = HIDMA_CH_STATE(val);
-	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
-	lldev->trch_state = HIDMA_CH_STATE(val);
-
-	/* already suspended by this OS */
-	if ((lldev->trch_state == HIDMA_CH_SUSPENDED) ||
-	    (lldev->evch_state == HIDMA_CH_SUSPENDED))
-		return 0;
-
-	/* already stopped by the manager */
-	if ((lldev->trch_state == HIDMA_CH_STOPPED) ||
-	    (lldev->evch_state == HIDMA_CH_STOPPED))
+	/* The channel needs to be in working state */
+	if (!hidma_ll_isenabled(lldev))
 		return 0;
 
 	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
-- 
1.9.1