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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16BD8C433FE for ; Fri, 12 Nov 2021 14:30:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0233360FE7 for ; Fri, 12 Nov 2021 14:30:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235341AbhKLOdE (ORCPT ); Fri, 12 Nov 2021 09:33:04 -0500 Received: from esa.microchip.iphmx.com ([68.232.154.123]:24737 "EHLO esa.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235352AbhKLOcw (ORCPT ); Fri, 12 Nov 2021 09:32:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1636727401; x=1668263401; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=xR2xChyp+/mKKklRKz7BqV+4uXpgD6Ige3/1mbZJg+U=; b=dFqRZ87u9mfuc3IZkXKwYVOVBKpsRVti94OuYlN4IV2GxAffOwyimJgV rNJNIIddKvKgwsMe2fCvteoFlHlC2QgOIceTve/2nxWaLcElq8ulTTk43 CNHTibfAB3zimEI5UxJWeoI1R2QerRB88KcR95Ox26xWitOJ1ANCkIydt omXraPDJnh15SJbxslyAcnLY5zevBmRONhQmuW0VkHujaJlUxdjwhF7Jo 3Dv1ELW5SUQ8STkI7Xr711Nx61TNcf7ZBk5wu6cpE8B5OgzAbmiZDPmuz ewXXX8sN3G/QU62G//7KAFxp8Uzx+mvbr7KxCA0nPcQgUyGsbOz0FQxE3 Q==; IronPort-SDR: KahGdEZzvc3gjvvEThA+XPCTEMzh3cKov3OuH40yz+SErzcb60v000cVJBc0dj0yemtXpurJ7T Q6nX0778G1ono5sPyqOanmgNDTnm/KSg+zgktkV1MaRos1ojqiFZKzuCtDnfoBscrNbAJ32mr5 tH44jZ/nyUJSL8n85FFRVaM9zDTK5faKx697j1SI5RdyTLn+mF2WEKl3pXWiw8kjH5OEfnSVbE Jbk/lWQ61IvswRZUYc6CQSsJG7wFUD2UFT58S79r4LsEOuO4IilrjPEGuNM0NtfQGg+8xXCwK1 iZ9xvPl20AUO8ZOIy8GqMm6b X-IronPort-AV: E=Sophos;i="5.87,229,1631602800"; d="scan'208";a="76260959" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa6.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 12 Nov 2021 07:30:01 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.14; Fri, 12 Nov 2021 07:30:00 -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 15.1.2176.14 via Frontend Transport; Fri, 12 Nov 2021 07:29:49 -0700 From: Eugen Hristev To: CC: , , , , , , , Eugen Hristev Subject: [PATCH v2 19/25] media: atmel: atmel-isc-base: use mutex to lock awb workqueue from streaming Date: Fri, 12 Nov 2021 16:25:03 +0200 Message-ID: <20211112142509.2230884-20-eugen.hristev@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211112142509.2230884-1-eugen.hristev@microchip.com> References: <20211112142509.2230884-1-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