From patchwork Mon May 8 15:03:16 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sakari Ailus X-Patchwork-Id: 9716305 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 4A96D6035D for ; Mon, 8 May 2017 15:04:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3E5B420453 for ; Mon, 8 May 2017 15:04:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 32C9A2094F; Mon, 8 May 2017 15:04:33 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 8384520453 for ; Mon, 8 May 2017 15:04:32 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 65F6288BBA; Mon, 8 May 2017 15:04:30 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id CFA5788F9B for ; Mon, 8 May 2017 15:04:29 +0000 (UTC) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga105.jf.intel.com with ESMTP; 08 May 2017 08:04:29 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.38,309,1491289200"; d="scan'208";a="965843060" Received: from paasikivi.fi.intel.com ([10.237.72.42]) by orsmga003.jf.intel.com with ESMTP; 08 May 2017 08:04:26 -0700 Received: from nauris.fi.intel.com (nauris.localdomain [192.168.240.2]) by paasikivi.fi.intel.com (Postfix) with ESMTP id C33DA20E04; Mon, 8 May 2017 18:04:25 +0300 (EEST) Received: by nauris.fi.intel.com (Postfix, from userid 1000) id F3B95201B7; Mon, 8 May 2017 18:03:30 +0300 (EEST) From: Sakari Ailus To: linux-media@vger.kernel.org Subject: [RFC v4 04/18] v4l: Unify cache management hint buffer flags Date: Mon, 8 May 2017 18:03:16 +0300 Message-Id: <1494255810-12672-5-git-send-email-sakari.ailus@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1494255810-12672-1-git-send-email-sakari.ailus@linux.intel.com> References: <1494255810-12672-1-git-send-email-sakari.ailus@linux.intel.com> Cc: daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org, hverkuil@xs4all.nl, kyungmin.park@samsung.com, laurent.pinchart@ideasonboard.com, posciak@chromium.org, m.szyprowski@samsung.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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 ae6ee73..9eb42bd 100644 --- a/Documentation/media/uapi/v4l/buffer.rst +++ b/Documentation/media/uapi/v4l/buffer.rst @@ -559,23 +559,17 @@ 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. This 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 bdcfd9f..80aeb7e 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 b3a85b3..3d5897d 100644 --- a/include/trace/events/v4l2.h +++ b/include/trace/events/v4l2.h @@ -81,8 +81,7 @@ 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 2b8feb8..2e046bb 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -939,8 +939,11 @@ 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