From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D42EC43381 for ; Fri, 29 Mar 2019 21:32:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 551CF218A2 for ; Fri, 29 Mar 2019 21:32:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730086AbfC2VcX (ORCPT ); Fri, 29 Mar 2019 17:32:23 -0400 Received: from mga17.intel.com ([192.55.52.151]:51430 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729771AbfC2VcW (ORCPT ); Fri, 29 Mar 2019 17:32:22 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Mar 2019 14:27:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,286,1549958400"; d="scan'208";a="332020655" Received: from maru.jf.intel.com ([10.54.51.75]) by fmsmga006.fm.intel.com with ESMTP; 29 Mar 2019 14:27:20 -0700 From: Jae Hyun Yoo To: Eddie James , Mauro Carvalho Chehab , Joel Stanley , Andrew Jeffery Cc: linux-aspeed@lists.ozlabs.org, linux-media@vger.kernel.org, Jae Hyun Yoo Subject: [PATCH v2] media: platform: fix a kernel warning on clk control Date: Fri, 29 Mar 2019 14:27:10 -0700 Message-Id: <20190329212710.5378-1-jae.hyun.yoo@linux.intel.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org video_on and video_off functions in the Aspeed video engine driver are being called from multiple contexts without any protection so video clocks can be disabled twice and eventually it causes a kernel warning with stack dump printing out like below: [ 120.034729] WARNING: CPU: 0 PID: 1334 at drivers/clk/clk.c:684 clk_core_unprepare+0x13c/0x170 [ 120.043252] eclk-gate already unprepared [ 120.047283] CPU: 0 PID: 1334 Comm: obmc-ikvm Tainted: G W 5.0.3-b94b74e8b52db91fe4e99e0bb481ec8bf2b5b47c #1 [ 120.058417] Hardware name: Generic DT based system [ 120.063219] Backtrace: [ 120.065787] [<80107cdc>] (dump_backtrace) from [<80107f10>] (show_stack+0x20/0x24) [ 120.073371] r7:803a4ff0 r6:00000009 r5:00000000 r4:96197e1c [ 120.079152] [<80107ef0>] (show_stack) from [<8068f7d8>] (dump_stack+0x20/0x28) [ 120.086479] [<8068f7b8>] (dump_stack) from [<8011604c>] (__warn.part.3+0xb4/0xdc) [ 120.094068] [<80115f98>] (__warn.part.3) from [<801160e0>] (warn_slowpath_fmt+0x6c/0x90) [ 120.102164] r6:000002ac r5:8080c0b8 r4:80a07008 [ 120.106893] [<80116078>] (warn_slowpath_fmt) from [<803a4ff0>] (clk_core_unprepare+0x13c/0x170) [ 120.115686] r3:8080cf8c r2:8080c17c [ 120.119276] r7:97d68e58 r6:9df23200 r5:9668c260 r4:96459260 [ 120.125046] [<803a4eb4>] (clk_core_unprepare) from [<803a707c>] (clk_unprepare+0x34/0x3c) [ 120.133226] r5:9668c260 r4:96459260 [ 120.136932] [<803a7048>] (clk_unprepare) from [<804f34bc>] (aspeed_video_off+0x44/0x48) [ 120.145031] r5:9668c260 r4:9668cbc0 [ 120.148647] [<804f3478>] (aspeed_video_off) from [<804f3fd0>] (aspeed_video_release+0x94/0x118) [ 120.157435] r5:966a0cb8 r4:966a0800 [ 120.161049] [<804f3f3c>] (aspeed_video_release) from [<804d2c58>] (v4l2_release+0xd4/0xe8) [ 120.169404] r7:97d68e58 r6:9d087810 r5:9df23200 r4:966a0b20 [ 120.175168] [<804d2b84>] (v4l2_release) from [<80236224>] (__fput+0x98/0x1c4) [ 120.182316] r5:96698e78 r4:9df23200 [ 120.185994] [<8023618c>] (__fput) from [<802363b8>] (____fput+0x18/0x1c) [ 120.192712] r9:80a0700c r8:801011e4 r7:00000000 r6:80a64bbc r5:961dd560 r4:961dd89c [ 120.200562] [<802363a0>] (____fput) from [<80131c08>] (task_work_run+0x7c/0xa4) [ 120.207994] [<80131b8c>] (task_work_run) from [<80106884>] (do_work_pending+0x4a8/0x578) [ 120.216163] r7:801011e4 r6:80a07008 r5:96197fb0 r4:ffffe000 [ 120.221856] [<801063dc>] (do_work_pending) from [<8010106c>] (slow_work_pending+0xc/0x20) [ 120.230116] Exception stack(0x96197fb0 to 0x96197ff8) [ 120.235254] 7fa0: 00000000 76ccf094 00000000 00000000 [ 120.243438] 7fc0: 00000008 00a11978 7eab3c30 00000006 00000000 00000000 475b0fa4 00000000 [ 120.251692] 7fe0: 00000002 7eab3a40 00000000 47720e38 80000010 00000008 [ 120.258396] r10:00000000 r9:96196000 r8:801011e4 r7:00000006 r6:7eab3c30 r5:00a11978 [ 120.266291] r4:00000008 To prevent this issue, this commit adds spinlock protection and clock status checking logic into the Aspeed video engine driver. Fixes: d2b4387f3bdf ("media: platform: Add Aspeed Video Engine driver") Signed-off-by: Jae Hyun Yoo Cc: Eddie James Cc: Mauro Carvalho Chehab Cc: Joel Stanley Cc: Andrew Jeffery --- drivers/media/platform/aspeed-video.c | 32 ++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c index 692e08ef38c0..744d22ecc620 100644 --- a/drivers/media/platform/aspeed-video.c +++ b/drivers/media/platform/aspeed-video.c @@ -188,6 +188,7 @@ enum { VIDEO_STREAMING, VIDEO_FRAME_INPRG, VIDEO_STOPPED, + VIDEO_CLOCKS_ON, }; struct aspeed_video_addr { @@ -495,20 +496,30 @@ static void aspeed_video_reset(struct aspeed_video *video) static void aspeed_video_off(struct aspeed_video *video) { + if (!test_bit(VIDEO_CLOCKS_ON, &video->flags)) + return; + aspeed_video_reset(video); /* 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); aspeed_video_reset(video); + + set_bit(VIDEO_CLOCKS_ON, &video->flags); } static void aspeed_video_bufs_done(struct aspeed_video *video, @@ -526,12 +537,14 @@ static void aspeed_video_bufs_done(struct aspeed_video *video, static void aspeed_video_irq_res_change(struct aspeed_video *video) { + spin_lock(&video->lock); dev_dbg(video->dev, "Resolution changed; resetting\n"); set_bit(VIDEO_RES_CHANGE, &video->flags); clear_bit(VIDEO_FRAME_INPRG, &video->flags); aspeed_video_off(video); + spin_unlock(&video->lock); aspeed_video_bufs_done(video, VB2_BUF_STATE_ERROR); schedule_delayed_work(&video->res_work, RESOLUTION_CHANGE_DELAY); @@ -951,9 +964,13 @@ static void aspeed_video_init_regs(struct aspeed_video *video) static void aspeed_video_start(struct aspeed_video *video) { + unsigned long flags; + + spin_lock_irqsave(&video->lock, flags); aspeed_video_on(video); aspeed_video_init_regs(video); + spin_unlock_irqrestore(&video->lock, flags); /* Resolution set to 640x480 if no signal found */ aspeed_video_get_resolution(video); @@ -969,6 +986,9 @@ static void aspeed_video_start(struct aspeed_video *video) static void aspeed_video_stop(struct aspeed_video *video) { + unsigned long flags; + + spin_lock_irqsave(&video->lock, flags); set_bit(VIDEO_STOPPED, &video->flags); cancel_delayed_work_sync(&video->res_work); @@ -982,6 +1002,7 @@ static void aspeed_video_stop(struct aspeed_video *video) video->v4l2_input_status = V4L2_IN_ST_NO_SIGNAL; video->flags = 0; + spin_unlock_irqrestore(&video->lock, flags); } static int aspeed_video_querycap(struct file *file, void *fh, @@ -1319,16 +1340,21 @@ static void aspeed_video_resolution_work(struct work_struct *work) struct delayed_work *dwork = to_delayed_work(work); struct aspeed_video *video = container_of(dwork, struct aspeed_video, res_work); - u32 input_status = video->v4l2_input_status; + unsigned long flags; + u32 input_status; + spin_lock_irqsave(&video->lock, flags); + input_status = video->v4l2_input_status; aspeed_video_on(video); /* Exit early in case no clients remain */ - if (test_bit(VIDEO_STOPPED, &video->flags)) + if (test_bit(VIDEO_STOPPED, &video->flags)) { + spin_unlock_irqrestore(&video->lock, flags); goto done; + } aspeed_video_init_regs(video); - + spin_unlock_irqrestore(&video->lock, flags); aspeed_video_get_resolution(video); if (video->detected_timings.width != video->active_timings.width || -- 2.21.0