Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1C92C433FE for ; Mon, 13 Dec 2021 13:54:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238366AbhLMNyx (ORCPT ); Mon, 13 Dec 2021 08:54:53 -0500 Received: from esa.microchip.iphmx.com ([68.232.154.123]:49313 "EHLO esa.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233777AbhLMNyw (ORCPT ); Mon, 13 Dec 2021 08:54:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1639403692; x=1670939692; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=xR2xChyp+/mKKklRKz7BqV+4uXpgD6Ige3/1mbZJg+U=; b=CCH06MthosI+EHT+l6xitXvWAKF2iofJNyAy5mtCQqv1l92HYD31Fdev OGZSkvse4GeH+NqljlYbEskl0LiGbG99gNgnD5K1TneMKKD49tBP9Opx1 /F+iglpC4JrFqIKMip93hayYLBYuhzVFVW9jSokxSz18RIDKZwA5y1gjy t5g0WyRlRnvb4z6lHgmvBH0s8rItfYtvsdZToUObRsayDOrgcKaHQhtkM uK/sahY79GmCuWFBQaaIOcv2Gb0vUat1Uh21yHh+Vh/QAHgLydg/qDA3E feZvxGuNGBujhNb6ynigmqqzZ65D1fABv93dSw8blp592oQ7Pot79auKc A==; IronPort-SDR: TvHHYOddhrzubtSz18kcERmffyHIs4gmtnUHAlQzRDZGiX92ymjmDIVLAgEc1hNoPo0M8XxUBb Kx/yFaq//ViyZMthlNhyqDA/u6BDLb4QHXb8OinT8p61izBGXCKOz/KCdXFp9XBYKEDTkLdmrO OexstHTQC7XYDZ38Qrgm5SOQg2bWuc/L3s6z5ZcMMM3r/3AB1Mypz41iMca0SxV69UJ9iB82L7 aTI+7UcxXkicaIqpU/OZqpDOdYwAWUlW84myvf1GJ0U0aBVmvglbyucmO0lkwHLvJEwdmUrrYi F79emERL2PIkPQOJZhH1LwVb X-IronPort-AV: E=Sophos;i="5.88,202,1635231600"; d="scan'208";a="79361943" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa6.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 13 Dec 2021 06:54:51 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.17; Mon, 13 Dec 2021 06:54:50 -0700 Received: from ROB-ULT-M18282.microchip.com (10.10.115.15) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2375.17 via Frontend Transport; Mon, 13 Dec 2021 06:54:24 -0700 From: Eugen Hristev To: , , , , CC: , , , , "Eugen Hristev" Subject: [PATCH v3 17/23] media: atmel: atmel-isc-base: use mutex to lock awb workqueue from streaming Date: Mon, 13 Dec 2021 15:49:34 +0200 Message-ID: <20211213134940.324266-18-eugen.hristev@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211213134940.324266-1-eugen.hristev@microchip.com> References: <20211213134940.324266-1-eugen.hristev@microchip.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The AWB workqueue runs in a kernel thread and needs to be synchronized w.r.t. the streaming status. It is possible that streaming is stopped while the AWB workq is running. In this case it is likely that the check for isc->stop is done at one point in time, but the AWB computations are done later, including a call to isc_update_profile, which requires streaming to be started. Thus , isc_update_profile will fail if during this operation sequence the streaming was stopped. To solve this issue, a mutex is added, that will serialize the awb work and streaming stopping, with the mention that either streaming is stopped completely including termination of the last frame is done, and after that the AWB work can check stream status and stop; either first AWB work is completed and after that the streaming can stop correctly. The awb spin lock cannot be used since this spinlock is taken in the same context and using it in the stop streaming will result in a recursion BUG. Signed-off-by: Eugen Hristev --- drivers/media/platform/atmel/atmel-isc-base.c | 31 ++++++++++++++++--- drivers/media/platform/atmel/atmel-isc.h | 1 + 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c index b0c3ed21f372..53cac1aac0fd 100644 --- a/drivers/media/platform/atmel/atmel-isc-base.c +++ b/drivers/media/platform/atmel/atmel-isc-base.c @@ -401,6 +401,7 @@ static void isc_stop_streaming(struct vb2_queue *vq) struct isc_buffer *buf; int ret; + mutex_lock(&isc->awb_mutex); v4l2_ctrl_activate(isc->do_wb_ctrl, false); isc->stop = true; @@ -410,6 +411,8 @@ static void isc_stop_streaming(struct vb2_queue *vq) v4l2_err(&isc->v4l2_dev, "Timeout waiting for end of the capture\n"); + mutex_unlock(&isc->awb_mutex); + /* Disable DMA interrupt */ regmap_write(isc->regmap, ISC_INTDIS, ISC_INT_DDONE); @@ -1416,10 +1419,6 @@ static void isc_awb_work(struct work_struct *w) u32 min, max; int ret; - /* streaming is not active anymore */ - if (isc->stop) - return; - if (ctrls->hist_stat != HIST_ENABLED) return; @@ -1470,7 +1469,24 @@ static void isc_awb_work(struct work_struct *w) } regmap_write(regmap, ISC_HIS_CFG + isc->offsets.his, hist_id | baysel | ISC_HIS_CFG_RAR); + + /* + * We have to make sure the streaming has not stopped meanwhile. + * ISC requires a frame to clock the internal profile update. + * To avoid issues, lock the sequence with a mutex + */ + mutex_lock(&isc->awb_mutex); + + /* streaming is not active anymore */ + if (isc->stop) { + mutex_unlock(&isc->awb_mutex); + return; + }; + isc_update_profile(isc); + + mutex_unlock(&isc->awb_mutex); + /* if awb has been disabled, we don't need to start another histogram */ if (ctrls->awb) regmap_write(regmap, ISC_CTRLEN, ISC_CTRL_HISREQ); @@ -1549,6 +1565,8 @@ static int isc_s_awb_ctrl(struct v4l2_ctrl *ctrl) isc_update_awb_ctrls(isc); + mutex_lock(&isc->awb_mutex); + if (!isc->stop) { /* * If we are streaming, we can update profile to @@ -1563,6 +1581,7 @@ static int isc_s_awb_ctrl(struct v4l2_ctrl *ctrl) */ v4l2_ctrl_activate(isc->do_wb_ctrl, false); } + mutex_unlock(&isc->awb_mutex); /* if we have autowhitebalance on, start histogram procedure */ if (ctrls->awb == ISC_WB_AUTO && !isc->stop && @@ -1754,6 +1773,7 @@ static void isc_async_unbind(struct v4l2_async_notifier *notifier, { struct isc_device *isc = container_of(notifier->v4l2_dev, struct isc_device, v4l2_dev); + mutex_destroy(&isc->awb_mutex); cancel_work_sync(&isc->awb_work); video_unregister_device(&isc->video_dev); v4l2_ctrl_handler_free(&isc->ctrls.handler); @@ -1866,6 +1886,8 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier) isc->current_subdev = container_of(notifier, struct isc_subdev_entity, notifier); mutex_init(&isc->lock); + mutex_init(&isc->awb_mutex); + init_completion(&isc->comp); /* Initialize videobuf2 queue */ @@ -1941,6 +1963,7 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier) video_unregister_device(vdev); isc_async_complete_err: + mutex_destroy(&isc->awb_mutex); mutex_destroy(&isc->lock); return ret; } diff --git a/drivers/media/platform/atmel/atmel-isc.h b/drivers/media/platform/atmel/atmel-isc.h index 0b6370d7775f..c2cb805faff3 100644 --- a/drivers/media/platform/atmel/atmel-isc.h +++ b/drivers/media/platform/atmel/atmel-isc.h @@ -307,6 +307,7 @@ struct isc_device { struct work_struct awb_work; struct mutex lock; /* serialize access to file operations */ + struct mutex awb_mutex; /* serialize access to streaming status from awb work queue */ spinlock_t awb_lock; /* serialize access to DMA buffers from awb work queue */ struct regmap_field *pipeline[ISC_PIPE_LINE_NODE_NUM]; -- 2.25.1