From patchwork Fri Jul 9 09:20:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergey Senozhatsky X-Patchwork-Id: 12367013 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 216E3C07E9C for ; Fri, 9 Jul 2021 09:20:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07A05613D9 for ; Fri, 9 Jul 2021 09:20:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231966AbhGIJXc (ORCPT ); Fri, 9 Jul 2021 05:23:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46134 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231956AbhGIJXb (ORCPT ); Fri, 9 Jul 2021 05:23:31 -0400 Received: from mail-pg1-x534.google.com (mail-pg1-x534.google.com [IPv6:2607:f8b0:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F556C0613E5 for ; Fri, 9 Jul 2021 02:20:48 -0700 (PDT) Received: by mail-pg1-x534.google.com with SMTP id k20so2378787pgg.7 for ; Fri, 09 Jul 2021 02:20:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=uAmRcbaeeTJjhJGcVBh7oioKghH7S05ftzUdU5WTJx4=; b=oUw1WP7NqxifoEcHeIl/ELb3bduD4HfDt/fOlwwJ8V6e7HRdPDviRFNowEYtvcIBbh CfhXhe3CtsPtn+EaI/9K7qV87HEadVcRuQKBknUKp25FGDrqoazKCdK88W6034EeK9VR OeQBmAws5JlYIXkz1cBnzFNMafu4X9Kw4Dopk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=uAmRcbaeeTJjhJGcVBh7oioKghH7S05ftzUdU5WTJx4=; b=cgnRyXCc4rru6Fl8KL4/OJpJDDO/50BFD8wFzvfDXu5Pn3LccmVQiWqJcPzjGSYH20 5gd0oLS1OA3a2Z15wemSTjVO+aLW+hWhm5JEWjluJTSnEylpvYhzzo4pVLp6xVl++zny 4YFZF9d/x48rVuIRAtrTRVqkAmpDc5Vvuflb/KpIWAtt0Ai8fKcmaZ0SC9X9q8VMu5w4 ZW7H0s269Ot5vENxk1AZIRgoPWak1QlxP1HDLArLAkMBu6bBcfRnM+3c5c6k8R9ev/Tw d071Ob4xkzyvEDJl/MwUWh3I+s//Cec5G8p1HWSNF64g/X5w6OJiReOaYFfQSp4hOE54 HEqg== X-Gm-Message-State: AOAM5322wie/QLsszu0rXMjhJvtY9CGidcLu8te5+pU+GBCeK0BIhz1Q qkXCMkWs2VfCzYnj4+ZVKYyj2A== X-Google-Smtp-Source: ABdhPJzO1nASMzj6MPp3FSju9sWhHis1VKSBSUNcPWJtJzLZcxPGwM2q8ILS4YMIoc5LW+zBpvauiQ== X-Received: by 2002:a63:234c:: with SMTP id u12mr36511673pgm.345.1625822448007; Fri, 09 Jul 2021 02:20:48 -0700 (PDT) Received: from senozhatsky.flets-east.jp ([2409:10:2e40:5100:a30d:fc4:7834:ee08]) by smtp.gmail.com with ESMTPSA id e24sm5496539pfn.127.2021.07.09.02.20.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Jul 2021 02:20:47 -0700 (PDT) From: Sergey Senozhatsky To: Tomasz Figa , Hans Verkuil Cc: Ricardo Ribalda , Christoph Hellwig , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: [PATCHv3 5/8] videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag Date: Fri, 9 Jul 2021 18:20:24 +0900 Message-Id: <20210709092027.1050834-6-senozhatsky@chromium.org> X-Mailer: git-send-email 2.32.0.93.g670b81a890-goog In-Reply-To: <20210709092027.1050834-1-senozhatsky@chromium.org> References: <20210709092027.1050834-1-senozhatsky@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org By setting or clearing V4L2_MEMORY_FLAG_NON_COHERENT flag user-space should be able to hint vb2 that either a non-coherent (if supported) or coherent memory should be used for the buffer allocation. Signed-off-by: Sergey Senozhatsky --- .../userspace-api/media/v4l/buffer.rst | 40 ++++++++++++++++++- .../media/v4l/vidioc-reqbufs.rst | 5 ++- include/uapi/linux/videodev2.h | 2 + 3 files changed, 43 insertions(+), 4 deletions(-) diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst index e991ba73d873..4638ec64db00 100644 --- a/Documentation/userspace-api/media/v4l/buffer.rst +++ b/Documentation/userspace-api/media/v4l/buffer.rst @@ -676,8 +676,6 @@ Buffer Flags \normalsize -.. _memory-flags: - enum v4l2_memory ================ @@ -701,6 +699,44 @@ enum v4l2_memory - 4 - The buffer is used for :ref:`DMA shared buffer ` I/O. +.. _memory-flags: + +Memory Consistency Flags +------------------------ + +.. raw:: latex + + \small + +.. tabularcolumns:: |p{7.0cm}|p{2.1cm}|p{8.4cm}| + +.. cssclass:: longtable + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + :widths: 3 1 4 + + * .. _`V4L2-MEMORY-FLAG-NON-COHERENT`: + + - ``V4L2_MEMORY_FLAG_NON_COHERENT`` + - 0x00000001 + - A buffer is allocated either in coherent (it will be automatically + coherent between the CPU and the bus) or non-coherent memory. The + latter can provide performance gains, for instance the CPU cache + sync/flush operations can be avoided if the buffer is accessed by the + corresponding device only and the CPU does not read/write to/from that + buffer. However, this requires extra care from the driver -- it must + guarantee memory consistency by issuing a cache flush/sync when + consistency is needed. If this flag is set V4L2 will attempt to + allocate the buffer in non-coherent memory. The flag takes effect + only if the buffer is used for :ref:`memory mapping ` I/O and the + queue reports the :ref:`V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS + ` capability. + +.. raw:: latex + + \normalsize Timecodes ========= diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst index 50ea72043bb0..e59306aba2b0 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst @@ -158,8 +158,9 @@ aborting or finishing any DMA in progress, an implicit - This capability is set by the driver to indicate that the queue supports cache and memory management hints. However, it's only valid when the queue is used for :ref:`memory mapping ` streaming I/O. See - :ref:`V4L2_BUF_FLAG_NO_CACHE_INVALIDATE ` and - :ref:`V4L2_BUF_FLAG_NO_CACHE_CLEAN `. + :ref:`V4L2_BUF_FLAG_NO_CACHE_INVALIDATE `, + :ref:`V4L2_BUF_FLAG_NO_CACHE_CLEAN ` and + :ref:`V4L2_MEMORY_FLAG_NON_COHERENT `. .. raw:: latex diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index 9260791b8438..9d11e1d9c934 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -956,6 +956,8 @@ struct v4l2_requestbuffers { __u32 reserved[1]; }; +#define V4L2_MEMORY_FLAG_NON_COHERENT (1 << 0) + /* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */ #define V4L2_BUF_CAP_SUPPORTS_MMAP (1 << 0) #define V4L2_BUF_CAP_SUPPORTS_USERPTR (1 << 1)