[PATCH AUTOSEL 5.2 071/249] media: aspeed: fix a kernel warning on clk control

From: Sasha Levin
Date: Mon Jul 15 2019 - 09:51:00 EST

From: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>

[ Upstream commit 9698ed4d4a2993ce54b9f7d71a2891e972caa117 ]

Video engine clock control can be double disabled and eventually
it causes a kernel warning with stack dump printing out like below:

[ 515.540498] ------------[ cut here ]------------
[ 515.545174] WARNING: CPU: 0 PID: 1310 at drivers/clk/clk.c:684 clk_core_unprepare+0x13c/0x170
[ 515.553806] vclk-gate already unprepared
[ 515.557841] CPU: 0 PID: 1310 Comm: obmc-ikvm Tainted: G W 5.0.6-df66fbc97853fbba90a0bfa44de32f3d5f7602b4 #1
[ 515.568973] Hardware name: Generic DT based system
[ 515.573777] Backtrace:
[ 515.576272] [<80107cdc>] (dump_backtrace) from [<80107f10>] (show_stack+0x20/0x24)
[ 515.583930] r7:803a5614 r6:00000009 r5:00000000 r4:9d88fe1c
[ 515.589712] [<80107ef0>] (show_stack) from [<80690184>] (dump_stack+0x20/0x28)
[ 515.597053] [<80690164>] (dump_stack) from [<80116044>] (__warn.part.3+0xb4/0xdc)
[ 515.604557] [<80115f90>] (__warn.part.3) from [<801160d8>] (warn_slowpath_fmt+0x6c/0x90)
[ 515.612734] r6:000002ac r5:8080befc r4:80a07008
[ 515.617463] [<80116070>] (warn_slowpath_fmt) from [<803a5614>] (clk_core_unprepare+0x13c/0x170)
[ 515.626167] r3:8080cdf4 r2:8080bfc0
[ 515.629834] r7:98d682a8 r6:9d8a9200 r5:9e5151a0 r4:97abd620
[ 515.635530] [<803a54d8>] (clk_core_unprepare) from [<803a76a4>] (clk_unprepare+0x34/0x3c)
[ 515.643812] r5:9e5151a0 r4:97abd620
[ 515.647529] [<803a7670>] (clk_unprepare) from [<804f36ec>] (aspeed_video_off+0x38/0x50)
[ 515.655539] r5:9e5151a0 r4:9e504000
[ 515.659242] [<804f36b4>] (aspeed_video_off) from [<804f4358>] (aspeed_video_release+0x90/0x114)
[ 515.668036] r5:9e5044b0 r4:9e504000
[ 515.671643] [<804f42c8>] (aspeed_video_release) from [<804d302c>] (v4l2_release+0xd4/0xe8)
[ 515.679999] r7:98d682a8 r6:9d087810 r5:9d8a9200 r4:9e504318
[ 515.685695] [<804d2f58>] (v4l2_release) from [<80236454>] (__fput+0x98/0x1c4)
[ 515.692914] r5:9e51b608 r4:9d8a9200
[ 515.696597] [<802363bc>] (__fput) from [<802365e8>] (____fput+0x18/0x1c)
[ 515.703315] r9:80a0700c r8:801011e4 r7:00000000 r6:80a64b9c r5:9d8e35a0 r4:9d8e38dc
[ 515.711167] [<802365d0>] (____fput) from [<80131ca4>] (task_work_run+0x7c/0xa0)
[ 515.718596] [<80131c28>] (task_work_run) from [<80106884>] (do_work_pending+0x4a8/0x578)
[ 515.726777] r7:801011e4 r6:80a07008 r5:9d88ffb0 r4:ffffe000
[ 515.732466] [<801063dc>] (do_work_pending) from [<8010106c>] (slow_work_pending+0xc/0x20)
[ 515.740727] Exception stack(0x9d88ffb0 to 0x9d88fff8)
[ 515.745840] ffa0: 00000000 76f18094 00000000 00000000
[ 515.754122] ffc0: 00000007 00176778 7eda4c20 00000006 00000000 00000000 48e20fa4 00000000
[ 515.762386] ffe0: 00000002 7eda4b08 00000000 48f91efc 80000010 00000007
[ 515.769097] r10:00000000 r9:9d88e000 r8:801011e4 r7:00000006 r6:7eda4c20 r5:00176778
[ 515.777006] r4:00000007
[ 515.779558] ---[ end trace 12c04aadef8afbbb ]---
[ 515.784176] ------------[ cut here ]------------
[ 515.788817] WARNING: CPU: 0 PID: 1310 at drivers/clk/clk.c:825 clk_core_disable+0x18c/0x204
[ 515.797161] eclk-gate already disabled
[ 515.800916] CPU: 0 PID: 1310 Comm: obmc-ikvm Tainted: G W 5.0.6-df66fbc97853fbba90a0bfa44de32f3d5f7602b4 #1
[ 515.811945] Hardware name: Generic DT based system
[ 515.816730] Backtrace:
[ 515.819210] [<80107cdc>] (dump_backtrace) from [<80107f10>] (show_stack+0x20/0x24)
[ 515.826782] r7:803a5900 r6:00000009 r5:00000000 r4:9d88fe04
[ 515.832454] [<80107ef0>] (show_stack) from [<80690184>] (dump_stack+0x20/0x28)
[ 515.839687] [<80690164>] (dump_stack) from [<80116044>] (__warn.part.3+0xb4/0xdc)
[ 515.847170] [<80115f90>] (__warn.part.3) from [<801160d8>] (warn_slowpath_fmt+0x6c/0x90)
[ 515.855247] r6:00000339 r5:8080befc r4:80a07008
[ 515.859868] [<80116070>] (warn_slowpath_fmt) from [<803a5900>] (clk_core_disable+0x18c/0x204)
[ 515.868385] r3:8080cdd0 r2:8080c00c
[ 515.871957] r7:98d682a8 r6:9d8a9200 r5:97abd560 r4:97abd560
[ 515.877615] [<803a5774>] (clk_core_disable) from [<803a59a0>] (clk_core_disable_lock+0x28/0x34)
[ 515.886301] r7:98d682a8 r6:9d8a9200 r5:97abd560 r4:a0000013
[ 515.891960] [<803a5978>] (clk_core_disable_lock) from [<803a7714>] (clk_disable+0x2c/0x30)
[ 515.900216] r5:9e5151a0 r4:9e515f60
[ 515.903816] [<803a76e8>] (clk_disable) from [<804f36f8>] (aspeed_video_off+0x44/0x50)
[ 515.911656] [<804f36b4>] (aspeed_video_off) from [<804f4358>] (aspeed_video_release+0x90/0x114)
[ 515.920341] r5:9e5044b0 r4:9e504000
[ 515.923921] [<804f42c8>] (aspeed_video_release) from [<804d302c>] (v4l2_release+0xd4/0xe8)
[ 515.932184] r7:98d682a8 r6:9d087810 r5:9d8a9200 r4:9e504318
[ 515.937851] [<804d2f58>] (v4l2_release) from [<80236454>] (__fput+0x98/0x1c4)
[ 515.944980] r5:9e51b608 r4:9d8a9200
[ 515.948559] [<802363bc>] (__fput) from [<802365e8>] (____fput+0x18/0x1c)
[ 515.955257] r9:80a0700c r8:801011e4 r7:00000000 r6:80a64b9c r5:9d8e35a0 r4:9d8e38dc
[ 515.963008] [<802365d0>] (____fput) from [<80131ca4>] (task_work_run+0x7c/0xa0)
[ 515.970333] [<80131c28>] (task_work_run) from [<80106884>] (do_work_pending+0x4a8/0x578)
[ 515.978421] r7:801011e4 r6:80a07008 r5:9d88ffb0 r4:ffffe000
[ 515.984086] [<801063dc>] (do_work_pending) from [<8010106c>] (slow_work_pending+0xc/0x20)
[ 515.992247] Exception stack(0x9d88ffb0 to 0x9d88fff8)
[ 515.997296] ffa0: 00000000 76f18094 00000000 00000000
[ 516.005473] ffc0: 00000007 00176778 7eda4c20 00000006 00000000 00000000 48e20fa4 00000000
[ 516.013642] ffe0: 00000002 7eda4b08 00000000 48f91efc 80000010 00000007
[ 516.020257] r10:00000000 r9:9d88e000 r8:801011e4 r7:00000006 r6:7eda4c20 r5:00176778
[ 516.028072] r4:00000007
[ 516.030606] ---[ end trace 12c04aadef8afbbc ]---

To prevent this issue, this commit adds clock status checking
logic into the Aspeed video engine driver.

Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
Reviewed-by: Eddie James <eajames@xxxxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/media/platform/aspeed-video.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
index 76d7512c82a3..de0f192afa8b 100644
--- a/drivers/media/platform/aspeed-video.c
+++ b/drivers/media/platform/aspeed-video.c
@@ -187,6 +187,7 @@ enum {
VIDEO_STREAMING,
VIDEO_FRAME_INPRG,
VIDEO_STOPPED,
+ VIDEO_CLOCKS_ON,
};

struct aspeed_video_addr {
@@ -483,19 +484,29 @@ static void aspeed_video_enable_mode_detect(struct aspeed_video *video)

static void aspeed_video_off(struct aspeed_video *video)
{
+ if (!test_bit(VIDEO_CLOCKS_ON, &video->flags))
+ return;
+
/* Disable interrupts */
aspeed_video_write(video, VE_INTERRUPT_CTRL, 0);

/* Turn off the relevant clocks */
clk_disable_unprepare(video->vclk);
clk_disable_unprepare(video->eclk);
+
+ clear_bit(VIDEO_CLOCKS_ON, &video->flags);
}

static void aspeed_video_on(struct aspeed_video *video)
{
+ if (test_bit(VIDEO_CLOCKS_ON, &video->flags))
+ return;
+
/* Turn on the relevant clocks */
clk_prepare_enable(video->eclk);
clk_prepare_enable(video->vclk);
+
+ set_bit(VIDEO_CLOCKS_ON, &video->flags);
}

static void aspeed_video_bufs_done(struct aspeed_video *video,
--
2.20.1