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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA96BC433F5 for ; Thu, 10 Mar 2022 09:53:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241026AbiCJJyC (ORCPT ); Thu, 10 Mar 2022 04:54:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241000AbiCJJxt (ORCPT ); Thu, 10 Mar 2022 04:53:49 -0500 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.153.233]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DB352644; Thu, 10 Mar 2022 01:52:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1646905966; x=1678441966; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=LThCuAfW7xET2MZo5q9C4gm+wpOhS9QVzkmQqBCA9Y8=; b=G3KUvY6BVKJgpAagRumJGmvKE15Vew73F0XwSca3ppFUyIPn4VNHd0C7 Gnb7Z8gn2syEb94btDhFz82m+kksStxtTpknSetakPgSHWzTEFGhoc753 woVzqTcUR2FO2xuNaZBtUvJlMBM98IhLsPfPr3lZ3TTdlKlALypkq6sjw aiCAuwUlG7tQeirOoOLLHaBWKAmJM51qOmmgsMkyZBu/5vof7Gowc91X1 SMAKU55WdTl/d90ths84LNTztOgyXWs80iXK/ZRQ2gd1Q9irPL9NGbOsz iBbX0gO6k0lboEWUAF2YJcdjPyct3R7svvB6yRRBL7tRjQZPU9I09Rygt Q==; X-IronPort-AV: E=Sophos;i="5.90,170,1643698800"; d="scan'208";a="165253128" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa1.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 10 Mar 2022 02:52:42 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.17; Thu, 10 Mar 2022 02:52:41 -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; Thu, 10 Mar 2022 02:52:37 -0700 From: Eugen Hristev To: , CC: , , , , , , Eugen Hristev Subject: [PATCH v9 06/13] media: atmel: atmel-isc-base: use mutex to lock awb workqueue from streaming Date: Thu, 10 Mar 2022 11:51:55 +0200 Message-ID: <20220310095202.2701399-7-eugen.hristev@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220310095202.2701399-1-eugen.hristev@microchip.com> References: <20220310095202.2701399-1-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 vb2_start_streaming_called 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 Reviewed-by: Jacopo Mondi --- drivers/media/platform/atmel/atmel-isc-base.c | 29 ++++++++++++++++--- drivers/media/platform/atmel/atmel-isc.h | 2 ++ 2 files changed, 27 insertions(+), 4 deletions(-) diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c index 448bf281c61a..ee1dda6707a0 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); @@ -1397,10 +1400,6 @@ 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; @@ -1455,7 +1454,24 @@ 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); @@ -1548,6 +1564,7 @@ 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 && @@ -1740,6 +1757,7 @@ 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); @@ -1850,6 +1868,8 @@ 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 */ @@ -1930,6 +1950,7 @@ 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 9cc69c3ae26d..f98f25a55e73 100644 --- a/drivers/media/platform/atmel/atmel-isc.h +++ b/drivers/media/platform/atmel/atmel-isc.h @@ -229,6 +229,7 @@ enum isc_scaler_pads { * * @lock: lock for serializing userspace file operations * with ISC operations + * @awb_mutex: serialize access to streaming status from awb work queue * @awb_lock: lock for serializing awb work queue operations * with DMA/buffer operations * @@ -307,6 +308,7 @@ struct isc_device { struct work_struct awb_work; struct mutex lock; + struct mutex awb_mutex; spinlock_t awb_lock; struct regmap_field *pipeline[ISC_PIPE_LINE_NODE_NUM]; -- 2.25.1