linux-kernel - [PATCH AUTOSEL for 4.15 102/102] dmaengine: qcom

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Date:   Sat, 3 Mar 2018 22:25:08 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
CC:     Sinan Kaya <okaya@...eaurora.org>,
        Vinod Koul <vinod.koul@...el.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.15 102/102] dmaengine: qcom_hidma: check pending
 interrupts

From: Sinan Kaya <okaya@...eaurora.org>

[ 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.

Signed-off-by: Sinan Kaya <okaya@...eaurora.org>
Signed-off-by: Vinod Koul <vinod.koul@...el.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/dma/qcom/hidma_ll.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/qcom/hidma_ll.c b/drivers/dma/qcom/hidma_ll.c
index 4999e266b2de..7c6e2ff212a2 100644
--- a/drivers/dma/qcom/hidma_ll.c
+++ b/drivers/dma/qcom/hidma_ll.c
@@ -393,6 +393,8 @@ static int hidma_ll_reset(struct hidma_lldev *lldev)
  */
 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_internal(struct hidma_lldev *lldev, int cause)
 		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_internal(struct hidma_lldev *lldev, int cause)
 	 * 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)
-- 
2.14.1