From patchwork Mon Aug 23 12:22:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergey Senozhatsky X-Patchwork-Id: 12452649 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=-19.5 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 81BB7C432BE for ; Mon, 23 Aug 2021 12:23:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 662AE6138E for ; Mon, 23 Aug 2021 12:23:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237170AbhHWMXu (ORCPT ); Mon, 23 Aug 2021 08:23:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237147AbhHWMXt (ORCPT ); Mon, 23 Aug 2021 08:23:49 -0400 Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D1A6C061760 for ; Mon, 23 Aug 2021 05:23:07 -0700 (PDT) Received: by mail-pf1-x42d.google.com with SMTP id a21so15205309pfh.5 for ; Mon, 23 Aug 2021 05:23:07 -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=kl9D+jL1lrKIs7+Zv10VN+k/0hE7ZG4QEhx3SFGsUvw=; b=K8YH2isw3JSzIWfsHxoAsS/N670qqv2iMRMWQSpu4njRUXmggvxo8BLT92x2XLQTkE wUUBXPn4LtfsumZwl5qQJUetjM3RYDvbQ/7t8RpCCa2IiwGhX5F4sqc6F95E64e5qa6M wc0hQqGL5zKJ9w+VeXZCXzwgHP0dtP3YXdnIs= 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=kl9D+jL1lrKIs7+Zv10VN+k/0hE7ZG4QEhx3SFGsUvw=; b=i7q/4hwhlTdeZ58TcfoXbW2YSrPia/BaLFS+03ZA8ruIg39aaL3iFb9KuK05i+cewa BkDvD749b3vTa8TjX0otRq6C/TbUz9OOyFCq+FC9gP73UE6I9hojDESPiEW0jbO6aawo VP+1kT8y1AOE9G7zIaQlcpVA7E0DCI4/rzXc00bPIlYRzVJIm7OExoDjaCP9ahido0GP 73JvxY/I1pQRDUXbhbb8Qdxfzr20z5RKNqEtbIsvr+coBxLamBhJCyTV8MeaD+FRDMml kOfLNNNnCjgthlfPlG1xyaE+1mJRN1nXsG7AWzeLYVl58rTfPJSzRTZchIqc7h6vtkfB aLog== X-Gm-Message-State: AOAM5330hKjL1u9HdmEaKsjZ8VTRV2XGf7I1fEG3lWnyA8bvJ+jIRqjz L1c7cRtxmbdYRSqEJUZ5qF8eyA== X-Google-Smtp-Source: ABdhPJxxVZnoFnXZJWKmK88E/eWpUCVoS/pCcov+3jnbdrLDmrjY+LqGpCfLriAbIXy/EtsiiaRF0A== X-Received: by 2002:a63:cc0e:: with SMTP id x14mr32114324pgf.352.1629721386846; Mon, 23 Aug 2021 05:23:06 -0700 (PDT) Received: from senozhatsky.flets-east.jp ([2409:10:2e40:5100:8821:8b2f:2912:f9e4]) by smtp.gmail.com with ESMTPSA id a15sm9035576pfn.219.2021.08.23.05.23.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Aug 2021 05:23:06 -0700 (PDT) From: Sergey Senozhatsky To: Tomasz Figa , Hans Verkuil Cc: Marek Szyprowski , Dafna Hirschfeld , Ricardo Ribalda , Christoph Hellwig , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: [PATCHv5 5/8] videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag Date: Mon, 23 Aug 2021 21:22:32 +0900 Message-Id: <20210823122235.116189-6-senozhatsky@chromium.org> X-Mailer: git-send-email 2.33.0.rc2.250.ged5fa647cd-goog In-Reply-To: <20210823122235.116189-1-senozhatsky@chromium.org> References: <20210823122235.116189-1-senozhatsky@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org By setting or clearing the V4L2_MEMORY_FLAG_NON_COHERENT flag user-space should be able to hint vb2 that either 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 5cc9545feb40..9b7032abb2c7 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -962,6 +962,8 @@ 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)