linux-kernel - [PATCH v3] media: aspeed-video: ignore interrupts that aren't enabled

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Message-Id: <20210617220229.7352-1-zev@bewilderbeest.net>
Date:   Thu, 17 Jun 2021 17:02:29 -0500
From:   Zev Weiss <zev@...ilderbeest.net>
To:     Eddie James <eajames@...ux.ibm.com>
Cc:     Zev Weiss <zev@...ilderbeest.net>,
        Jae Hyun Yoo <jae.hyun.yoo@...ux.intel.com>,
        Joel Stanley <joel@....id.au>,
        Ryan Chen <ryan_chen@...eedtech.com>,
        linux-aspeed@...ts.ozlabs.org, Andrew Jeffery <andrew@...id.au>,
        openbmc@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org
Subject: [PATCH v3] media: aspeed-video: ignore interrupts that aren't enabled

As partially addressed in commit 65d270acb2d6 ("media: aspeed: clear
garbage interrupts"), the ASpeed video engine sometimes asserts
interrupts that the driver hasn't enabled.  In addition to the
CAPTURE_COMPLETE and FRAME_COMPLETE interrupts dealt with in that
patch, COMP_READY has also been observed.  Instead of playing
whack-a-mole with each one individually, we can instead just blanket
ignore everything we haven't explicitly enabled.

Signed-off-by: Zev Weiss <zev@...ilderbeest.net>
---

Changes since v2 [1]:
 - minor commit message improvements

Changes since v1 [0]:
 - dropped error message
 - switched to a blanket-ignore approach as suggested by Ryan

[0] https://lore.kernel.org/linux-arm-kernel/20201215024542.18888-1-zev@bewilderbeest.net/
[1] https://lore.kernel.org/openbmc/20210506234048.3214-1-zev@bewilderbeest.net/

 drivers/media/platform/aspeed-video.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
index 7bb6babdcade..77611c296a25 100644
--- a/drivers/media/platform/aspeed-video.c
+++ b/drivers/media/platform/aspeed-video.c
@@ -563,6 +563,12 @@ static irqreturn_t aspeed_video_irq(int irq, void *arg)
 	struct aspeed_video *video = arg;
 	u32 sts = aspeed_video_read(video, VE_INTERRUPT_STATUS);
 
+	/*
+	 * Hardware sometimes asserts interrupts that we haven't actually
+	 * enabled; ignore them if so.
+	 */
+	sts &= aspeed_video_read(video, VE_INTERRUPT_CTRL);
+
 	/*
 	 * Resolution changed or signal was lost; reset the engine and
 	 * re-initialize
@@ -629,16 +635,6 @@ static irqreturn_t aspeed_video_irq(int irq, void *arg)
 			aspeed_video_start_frame(video);
 	}
 
-	/*
-	 * CAPTURE_COMPLETE and FRAME_COMPLETE interrupts come even when these
-	 * are disabled in the VE_INTERRUPT_CTRL register so clear them to
-	 * prevent unnecessary interrupt calls.
-	 */
-	if (sts & VE_INTERRUPT_CAPTURE_COMPLETE)
-		sts &= ~VE_INTERRUPT_CAPTURE_COMPLETE;
-	if (sts & VE_INTERRUPT_FRAME_COMPLETE)
-		sts &= ~VE_INTERRUPT_FRAME_COMPLETE;
-
 	return sts ? IRQ_NONE : IRQ_HANDLED;
 }
 
-- 
2.32.0