Patch "dmaengine: qcom_hidma: check pending interrupts" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

dmaengine: qcom_hidma: check pending interrupts

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
dmaengine-qcom_hidma-check-pending-interrupts.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Sinan Kaya <[email protected]>
Date: Tue, 14 Nov 2017 09:55:01 -0500
Subject: dmaengine: qcom_hidma: check pending interrupts

From: Sinan Kaya <[email protected]>

[ Upstream commit 38680bc6b1e3592bc9e18adc1d6e259667df27ce ]

Driver is missing the interrupts if two requests are queued up at the same time as the interrupt handler is servicing a request that was just delivered.

The ISR clears the interrupt at the end but it could be clearing the interrupt for an outstanding event. Therefore, second interrupt never arrives.

Clear the interrupt first and then check for completions.

Also, make sure that request start and interrupt clear do not overlap in time by using a spinlock.

---
 drivers/dma/qcom/hidma_ll.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

@@ -393,6 +393,8 @@ static int hidma_ll_reset(struct hidma_l
  */
 static void hidma_ll_int_handler_internal(struct hidma_lldev *lldev, int cause)
 {
+	unsigned long irqflags;
+
 	if (cause & HIDMA_ERR_INT_MASK) {
 		dev_err(lldev->dev, "error 0x%x, disabling...\n",
 				cause);

@@ -410,6 +412,10 @@ static void hidma_ll_int_handler_interna
 		return;
 	}
 
+	spin_lock_irqsave(&lldev->lock, irqflags);
+	writel_relaxed(cause, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
+	spin_unlock_irqrestore(&lldev->lock, irqflags);
+
 	/*
 	 * Fine tuned for this HW...
 	 *

@@ -421,9 +427,6 @@ static void hidma_ll_int_handler_interna
 	 * Try to consume as many EVREs as possible.
 	 */
 	hidma_handle_tre_completion(lldev);
-
-	/* We consumed TREs or there are pending TREs or EVREs. */
-	writel_relaxed(cause, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
 }
 
 irqreturn_t hidma_ll_inthandler(int chirq, void *arg)

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/dmaengine-qcom_hidma-check-pending-interrupts.patch