From patchwork Fri Dec 16 01:24:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Pinchart X-Patchwork-Id: 9477167 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 93F6060827 for ; Fri, 16 Dec 2016 01:24:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8F70F28876 for ; Fri, 16 Dec 2016 01:24:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 84344288A7; Fri, 16 Dec 2016 01:24:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D8122288A3 for ; Fri, 16 Dec 2016 01:24:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757253AbcLPBYC (ORCPT ); Thu, 15 Dec 2016 20:24:02 -0500 Received: from galahad.ideasonboard.com ([185.26.127.97]:50169 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756817AbcLPBX6 (ORCPT ); Thu, 15 Dec 2016 20:23:58 -0500 Received: from avalon.bb.dnainternet.fi (dfj612ybrt5fhg77mgycy-3.rev.dnainternet.fi [IPv6:2001:14ba:21f5:5b00:2e86:4862:ef6a:2804]) by galahad.ideasonboard.com (Postfix) with ESMTPSA id C55EA207BA; Fri, 16 Dec 2016 02:23:41 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1481851422; bh=P4b/Dz03m3n6x7pUwTkTCm91DiShlXlyqovwK50v2Jc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H5tY3xN/JN5qhxEwMTKkxz5sl5PULFSUsfQX2m/ssR0AUz6VUNa+a6WScYE8iatsm OYEVeIq6LH6oDxEC7H//Iqvj0ehscBieRGGwoeeuHeJzq7pnukEGeH83NMxRvc1yJF Z/EUncxwWL0ix/T54wQW8Ncb9ZgqNqdaO7JWBYdU= From: Laurent Pinchart To: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org, Pawel Osciak , Marek Szyprowski , Kyungmin Park , Hans Verkuil , Sumit Semwal , Rob Clark , Daniel Vetter , Laura Abbott , Sakari Ailus Subject: [RFC v2 04/11] v4l: Unify cache management hint buffer flags Date: Fri, 16 Dec 2016 03:24:18 +0200 Message-Id: <20161216012425.11179-5-laurent.pinchart+renesas@ideasonboard.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161216012425.11179-1-laurent.pinchart+renesas@ideasonboard.com> References: <20161216012425.11179-1-laurent.pinchart+renesas@ideasonboard.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Sakari Ailus The V4L2_BUF_FLAG_NO_CACHE_INVALIDATE and V4L2_BUF_FLAG_NO_CACHE_CLEAN buffer flags are currently not used by the kernel. Replace the definitions by a single V4L2_BUF_FLAG_NO_CACHE_SYNC flag to be used by further patches. Different cache architectures should not be visible to the user space which can make no meaningful use of the differences anyway. In case a device can make use of non-coherent memory accesses, the necessary cache operations depend on the CPU architecture and the buffer type, not the requests of the user. The cache operation itself may be skipped on the user's request which was the purpose of the two flags. On ARM the invalidate and clean are separate operations whereas on x86(-64) the two are a single operation (flush). Whether the hardware uses the buffer for reading (V4L2_BUF_TYPE_*_OUTPUT*) or writing (V4L2_BUF_TYPE_*CAPTURE*) already defines the required cache operation (clean and invalidate, respectively). No user input is required. Signed-off-by: Sakari Ailus Acked-by: Hans Verkuil --- Documentation/media/uapi/v4l/buffer.rst | 24 ++++++++-------------- .../media/uapi/v4l/vidioc-prepare-buf.rst | 5 ++--- include/trace/events/v4l2.h | 3 +-- include/uapi/linux/videodev2.h | 7 +++++-- 4 files changed, 17 insertions(+), 22 deletions(-) diff --git a/Documentation/media/uapi/v4l/buffer.rst b/Documentation/media/uapi/v4l/buffer.rst index ac58966ccb9b..601c3e96464a 100644 --- a/Documentation/media/uapi/v4l/buffer.rst +++ b/Documentation/media/uapi/v4l/buffer.rst @@ -437,23 +437,17 @@ Buffer Flags :ref:`VIDIOC_PREPARE_BUF `, :ref:`VIDIOC_QBUF` or :ref:`VIDIOC_DQBUF ` ioctl is called. - * .. _`V4L2-BUF-FLAG-NO-CACHE-INVALIDATE`: + * .. _`V4L2-BUF-FLAG-NO-CACHE-SYNC`: - - ``V4L2_BUF_FLAG_NO_CACHE_INVALIDATE`` + - ``V4L2_BUF_FLAG_NO_CACHE_SYNC`` - 0x00000800 - - Caches do not have to be invalidated for this buffer. Typically - applications shall use this flag if the data captured in the - buffer is not going to be touched by the CPU, instead the buffer - will, probably, be passed on to a DMA-capable hardware unit for - further processing or output. - * .. _`V4L2-BUF-FLAG-NO-CACHE-CLEAN`: - - - ``V4L2_BUF_FLAG_NO_CACHE_CLEAN`` - - 0x00001000 - - Caches do not have to be cleaned for this buffer. Typically - applications shall use this flag for output buffers if the data in - this buffer has not been created by the CPU but by some - DMA-capable unit, in which case caches have not been used. + - Do not perform CPU cache synchronisation operations when the buffer is + queued or dequeued. The user is responsible for the correct use of + this flag. It should be only used when the buffer is not accessed + using the CPU, e.g. the buffer is written to by a hardware block and + then read by another one, in which case the flag should be set in both + :ref:`VIDIOC_QBUF` and :ref:`VIDIOC_DQBUF` ioctls. The flag has no + effect on some devices / architectures. * .. _`V4L2-BUF-FLAG-LAST`: - ``V4L2_BUF_FLAG_LAST`` diff --git a/Documentation/media/uapi/v4l/vidioc-prepare-buf.rst b/Documentation/media/uapi/v4l/vidioc-prepare-buf.rst index bdcfd9fe550d..80aeb7e403f3 100644 --- a/Documentation/media/uapi/v4l/vidioc-prepare-buf.rst +++ b/Documentation/media/uapi/v4l/vidioc-prepare-buf.rst @@ -36,9 +36,8 @@ pass ownership of the buffer to the driver before actually enqueuing it, using the :ref:`VIDIOC_QBUF` ioctl, and to prepare it for future I/O. Such preparations may include cache invalidation or cleaning. Performing them in advance saves time during the actual I/O. In case such cache -operations are not required, the application can use one of -``V4L2_BUF_FLAG_NO_CACHE_INVALIDATE`` and -``V4L2_BUF_FLAG_NO_CACHE_CLEAN`` flags to skip the respective step. +operations are not required, the application can use the +``V4L2_BUF_FLAG_NO_CACHE_SYNC`` flag to skip the cache synchronization step. The struct :c:type:`v4l2_buffer` structure is specified in :ref:`buffer`. diff --git a/include/trace/events/v4l2.h b/include/trace/events/v4l2.h index ee7754c6e4a1..fb9ad7b0dddd 100644 --- a/include/trace/events/v4l2.h +++ b/include/trace/events/v4l2.h @@ -80,8 +80,7 @@ SHOW_FIELD { V4L2_BUF_FLAG_ERROR, "ERROR" }, \ { V4L2_BUF_FLAG_TIMECODE, "TIMECODE" }, \ { V4L2_BUF_FLAG_PREPARED, "PREPARED" }, \ - { V4L2_BUF_FLAG_NO_CACHE_INVALIDATE, "NO_CACHE_INVALIDATE" }, \ - { V4L2_BUF_FLAG_NO_CACHE_CLEAN, "NO_CACHE_CLEAN" }, \ + { V4L2_BUF_FLAG_NO_CACHE_SYNC, "NO_CACHE_SYNC" }, \ { V4L2_BUF_FLAG_TIMESTAMP_MASK, "TIMESTAMP_MASK" }, \ { V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN, "TIMESTAMP_UNKNOWN" }, \ { V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC, "TIMESTAMP_MONOTONIC" }, \ diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index 46e8a2e369f9..3516dd638009 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -935,8 +935,11 @@ struct v4l2_buffer { #define V4L2_BUF_FLAG_TIMECODE 0x00000100 /* Buffer is prepared for queuing */ #define V4L2_BUF_FLAG_PREPARED 0x00000400 -/* Cache handling flags */ -#define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE 0x00000800 +/* Cache sync hint */ +#define V4L2_BUF_FLAG_NO_CACHE_SYNC 0x00000800 +/* DEPRECATED. THIS WILL BE REMOVED IN THE FUTURE! */ +#define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE V4L2_BUF_FLAG_NO_CACHE_SYNC +/* DEPRECATED. THIS WILL BE REMOVED IN THE FUTURE! */ #define V4L2_BUF_FLAG_NO_CACHE_CLEAN 0x00001000 /* Timestamp type */ #define V4L2_BUF_FLAG_TIMESTAMP_MASK 0x0000e000