From patchwork Sat Jul 20 10:46:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans Verkuil X-Patchwork-Id: 813659 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F12DE4779E for ; Sat, 20 Jul 2024 10:46:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721472414; cv=none; b=VTV3JgMBGd7JsEjvcIgpjForCAgh4HzgcjR1y6Nv2LEXSaE1ULGMvRMVbEK/4y7DVEirHLdOvMUi+VbPG42dUK2Fyea6ZnP3Zl3xhkTQGbPI/4xNKb84wZgB4x/4WE3o5jBxHdoa8d3Nx6pV3NfN6WY1YkM9SROY1vrX6B2lyKU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721472414; c=relaxed/simple; bh=ai6KA+Q5bk24vyOJ9J1YmjM3jFW/oOsltb6LRlBYiNM=; h=Message-ID:Date:MIME-Version:To:From:Subject:Content-Type; b=aqNLlPnLpliDkmbKkEoHMSJkm1w3evSg8GUNYZ5gmMjQprhLfnvNJQ1HwPdjTnE35t4HPHjRhqdQ636Zmm3n/y/D3S2JNKxQPkACHQPdzoxt9qZy5TBfL829Kmi+Shmw+qWbHs5BpH24a35w/3bT5upiwAqKLJFKxk2SeXQrCfU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B194C2BD10 for ; Sat, 20 Jul 2024 10:46:53 +0000 (UTC) Message-ID: Date: Sat, 20 Jul 2024 12:46:51 +0200 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US, nl To: Linux Media Mailing List From: Hans Verkuil Subject: [PATCH] Documentation: media: move Memory Consistency Flags The documentation of the Memory Consistency Flags was part of the struct v4l2_buffer documentation, but that struct doesn't use those flags. Instead it is used by VIDIOC_CREATE_BUFS and VIDIOC_REQBUFS. Move the documentation from buffer.rst to vidioc-reqbufs.rst which is where it belongs. Signed-off-by: Hans Verkuil diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst index 52bbee81c080..856874341882 100644 --- a/Documentation/userspace-api/media/v4l/buffer.rst +++ b/Documentation/userspace-api/media/v4l/buffer.rst @@ -694,41 +694,6 @@ 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 diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst index bbc22dd76032..634c2517221a 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst @@ -73,6 +73,8 @@ aborting or finishing any DMA in progress, an implicit .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| +.. cssclass:: longtable + .. flat-table:: struct v4l2_requestbuffers :header-rows: 0 :stub-columns: 0 @@ -123,14 +125,6 @@ aborting or finishing any DMA in progress, an implicit .. _V4L2-BUF-CAP-SUPPORTS-MAX-NUM-BUFFERS: .. _V4L2-BUF-CAP-SUPPORTS-REMOVE-BUFS: -.. raw:: latex - - \footnotesize - -.. tabularcolumns:: |p{8.1cm}|p{2.2cm}|p{7.0cm}| - -.. cssclass:: longtable - .. flat-table:: V4L2 Buffer Capabilities Flags :header-rows: 0 :stub-columns: 0 @@ -167,6 +161,29 @@ aborting or finishing any DMA in progress, an implicit :ref:`V4L2_BUF_FLAG_NO_CACHE_CLEAN ` and :ref:`V4L2_MEMORY_FLAG_NON_COHERENT `. +.. _memory-flags: +.. _V4L2-MEMORY-FLAG-NON-COHERENT: + +.. flat-table:: Memory Consistency Flags + :header-rows: 0 + :stub-columns: 0 + :widths: 3 1 4 + + * - ``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