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[PATCH 1/2] dmaengine: qcom_hidma: disable/enable IRQs on pause/resume

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  [PATCH 1/2] dmaengine: qcom_hidma: disable/enable IRQs on pause/resume Sinan Kaya <okaya@codeaurora.org> - 2017-03-26 00:10 +0100
    [PATCH 2/2] dmaengine: qcom_hidma: pause the channel on shutdown Sinan Kaya <okaya@codeaurora.org> - 2017-03-26 00:10 +0100
    Re: [PATCH 1/2] dmaengine: qcom_hidma: disable/enable IRQs on  pause/resume Vinod Koul <vinod.koul@intel.com> - 2017-03-27 07:20 +0200

#1609260 — [PATCH 1/2] dmaengine: qcom_hidma: disable/enable IRQs on pause/resume

Once the channels are stopped, disable interrupts to make sure no new
HW interaction can happen.

Similarly, re-enable the interrupts only if we know that channel is
operational again.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/dma/qcom/hidma_ll.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/dma/qcom/hidma_ll.c b/drivers/dma/qcom/hidma_ll.c
index 6645bdf..1530a66 100644
--- a/drivers/dma/qcom/hidma_ll.c
+++ b/drivers/dma/qcom/hidma_ll.c
@@ -499,6 +499,9 @@ int hidma_ll_enable(struct hidma_lldev *lldev)
 	lldev->trch_state = HIDMA_CH_ENABLED;
 	lldev->evch_state = HIDMA_CH_ENABLED;
 
+	/* enable irqs */
+	writel(ENABLE_IRQS, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
+
 	return 0;
 }
 
@@ -596,6 +599,9 @@ int hidma_ll_disable(struct hidma_lldev *lldev)
 
 	lldev->trch_state = HIDMA_CH_SUSPENDED;
 	lldev->evch_state = HIDMA_CH_SUSPENDED;
+
+	/* disable interrupts */
+	writel(0, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
 	return 0;
 }
 
-- 
1.9.1

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#1609261 — [PATCH 2/2] dmaengine: qcom_hidma: pause the channel on shutdown

We need to ensure that all DMAs and interrupts are cleared during
shutdown operation in order for kexec to start the next kernel clearly.

Otherwise, HW could be performing a DMA into random addresses in the
middle of second kernel start.

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

diff --git a/drivers/dma/qcom/hidma.c b/drivers/dma/qcom/hidma.c
index 3c982c9..5072a7d 100644
--- a/drivers/dma/qcom/hidma.c
+++ b/drivers/dma/qcom/hidma.c
@@ -865,6 +865,20 @@ static int hidma_probe(struct platform_device *pdev)
 	return rc;
 }
 
+static void hidma_shutdown(struct platform_device *pdev)
+{
+	struct hidma_dev *dmadev = platform_get_drvdata(pdev);
+
+	dev_info(dmadev->ddev.dev, "HI-DMA engine shutdown\n");
+
+	pm_runtime_get_sync(dmadev->ddev.dev);
+	if (hidma_ll_disable(dmadev->lldev))
+		dev_warn(dmadev->ddev.dev, "channel did not stop\n");
+	pm_runtime_mark_last_busy(dmadev->ddev.dev);
+	pm_runtime_put_autosuspend(dmadev->ddev.dev);
+
+}
+
 static int hidma_remove(struct platform_device *pdev)
 {
 	struct hidma_dev *dmadev = platform_get_drvdata(pdev);
@@ -908,6 +922,7 @@ static int hidma_remove(struct platform_device *pdev)
 static struct platform_driver hidma_driver = {
 	.probe = hidma_probe,
 	.remove = hidma_remove,
+	.shutdown = hidma_shutdown,
 	.driver = {
 		   .name = "hidma",
 		   .of_match_table = hidma_match,
-- 
1.9.1

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#1609450 — Re: [PATCH 1/2] dmaengine: qcom_hidma: disable/enable IRQs on pause/resume

On Sat, Mar 25, 2017 at 07:04:02PM -0400, Sinan Kaya wrote:
> Once the channels are stopped, disable interrupts to make sure no new
> HW interaction can happen.
> 
> Similarly, re-enable the interrupts only if we know that channel is
> operational again.

Applied both, thanks

-- 
~Vinod

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