From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D7C3199EAD; Mon, 30 Mar 2026 10:46:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774867609; cv=none; b=H6F3ji2CL0r7B/Ka3bDoTwDeMPkG7mvRJZzI9+hXQEfU53GMdarKqwFpuIzltWixBr3gkCg3eo1OUBqNEHVSX4qlWmNV06xTPK5Cyw41xR7w55xr3YHuIxbZZH/UHezkTiTwHii4ZchLMLQcJB3v42VxJbC8ju42jd08g7RXDXo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774867609; c=relaxed/simple; bh=IfLuRd6WK0NP79K39N3FZFdHua3GtggiRQm5XdkRClg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cgpgHMRWwkGvTtkh19y1YaLo0jchhgICCY4eNHa+wSS4SCieYVSO1SqVYJ6DeUfAAtZi/0EAwaojzQEtilBQCdkiRhBhP5YkbRoVrMznnSQ7erNF+X0wQ2FbqdPl6qlUiQ/7l8/Bsskl3eDZ9XI79Zz9gzjKbPw22zDq0ln3aRQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=nBCnOySc; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="nBCnOySc" Received: from [192.168.0.43] (cpc141996-chfd3-2-0-cust928.12-3.cable.virginm.net [86.13.91.161]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id BE7F93DA; Mon, 30 Mar 2026 12:45:22 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1774867523; bh=IfLuRd6WK0NP79K39N3FZFdHua3GtggiRQm5XdkRClg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=nBCnOySc8JUXIMslxFvPaWNks7InqSj1vcnHqG+DU+ilBaORJWNJWVpFz1T+ObXE9 qilr15c+9Tvsdnor3GqTmoypffibaxS6ujazURUDsq8QDBgOF6e+Z5nK8wlMeHUknh CeNY0JJD1yq2ZEAX6tVAce4vfnNhss/6DDzBURGI= Message-ID: Date: Mon, 30 Mar 2026 11:46:41 +0100 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 08/14] media: rz2gl-cru: Introduce a spinlock for hw operations To: Jacopo Mondi , Mauro Carvalho Chehab , Laurent Pinchart , Biju Das , Hans Verkuil , Sakari Ailus , Tommaso Merciai Cc: =?UTF-8?Q?Barnab=C3=A1s_P=C5=91cze?= , Lad Prabhakar , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Jacopo Mondi References: <20260327-b4-cru-rework-v1-0-3b7d0430f538@ideasonboard.com> <20260327-b4-cru-rework-v1-8-3b7d0430f538@ideasonboard.com> Content-Language: en-US From: Dan Scally In-Reply-To: <20260327-b4-cru-rework-v1-8-3b7d0430f538@ideasonboard.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Jacopo On 27/03/2026 17:10, Jacopo Mondi wrote: > From: Jacopo Mondi > > The CRU driver uses a single spinlock to protect the buffers queue and > the hardware operations. > > This single spinlock is held for the whole duration of the interrupt > handler, causing all other driver's operations to freeze. > > Under heavy system stress conditions with userspace not providing > buffers fast enough, this causes loss of frames. > > Prepare to re-work the driver locking by introducing (but not using yet) > a new spinlock to protect the hardware registers programming. > > Signed-off-by: Jacopo Mondi > --- Looks good: Reviewed-by: Daniel Scally > drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h | 10 +++++++--- > drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c | 1 + > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h > index 3a200db15730..b46696a0012b 100644 > --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h > +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h > @@ -109,7 +109,6 @@ struct rzg2l_cru_info { > * @v4l2_dev: V4L2 device > * @num_buf: Holds the current number of buffers enabled > * @svc_channel: SVC0/1/2/3 to use for RZ/G3E > - * @buf_addr: Memory addresses where current video data is written. > * @notifier: V4L2 asynchronous subdevs notifier > * > * @ip: Image processing subdev info > @@ -118,6 +117,10 @@ struct rzg2l_cru_info { > * @mdev_lock: protects the count, notifier and csi members > * @pad: media pad for the video device entity > * > + * @hw_lock: protects the slot counter, hardware programming of > + * slot addresses and the @buf_addr[] list > + * @buf_addr: Memory addresses where current video data is written > + * > * @lock: protects @queue > * @queue: vb2 buffers queue > * @scratch: cpu address for scratch buffer > @@ -147,8 +150,6 @@ struct rzg2l_cru_dev { > u8 num_buf; > > u8 svc_channel; > - dma_addr_t buf_addr[RZG2L_CRU_HW_BUFFER_DEFAULT]; > - > struct v4l2_async_notifier notifier; > > struct rzg2l_cru_ip ip; > @@ -157,6 +158,9 @@ struct rzg2l_cru_dev { > struct mutex mdev_lock; > struct media_pad pad; > > + spinlock_t hw_lock; > + dma_addr_t buf_addr[RZG2L_CRU_HW_BUFFER_DEFAULT]; > + > struct mutex lock; > struct vb2_queue queue; > void *scratch; > diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c > index 27079c17a54c..a79b17e146bf 100644 > --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c > +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c > @@ -844,6 +844,7 @@ int rzg2l_cru_dma_register(struct rzg2l_cru_dev *cru) > mutex_init(&cru->lock); > INIT_LIST_HEAD(&cru->buf_list); > > + spin_lock_init(&cru->hw_lock); > spin_lock_init(&cru->qlock); > > cru->state = RZG2L_CRU_DMA_STOPPED; >