From patchwork Tue Feb 4 02:56:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergey Senozhatsky X-Patchwork-Id: 11363933 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EB691186E for ; Tue, 4 Feb 2020 02:57:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C78F1218AC for ; Tue, 4 Feb 2020 02:57:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="hAKlVKM+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727218AbgBDC5C (ORCPT ); Mon, 3 Feb 2020 21:57:02 -0500 Received: from mail-pj1-f67.google.com ([209.85.216.67]:35016 "EHLO mail-pj1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727084AbgBDC5A (ORCPT ); Mon, 3 Feb 2020 21:57:00 -0500 Received: by mail-pj1-f67.google.com with SMTP id q39so704456pjc.0 for ; Mon, 03 Feb 2020 18:57:00 -0800 (PST) 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=Icxfnp9HKjOCxxd8LHDLtBzlH++tvRBMGK02TWhaPYI=; b=hAKlVKM+cc2osv8Wzq1OdoAIc0gwS/b7aByJyCTRrUEWILDvQchLX65IYYHuMNs4E8 CDdgtxQC2e//gNJXvwuLkaf1Jc6tsm0AM6UNh8PI1AR7GVWNABSDRdQOvy4qpiV35OHK TF/pS1ub1obJ8GAdEHFN4DuUFdUjCgTQrZDuQ= 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=Icxfnp9HKjOCxxd8LHDLtBzlH++tvRBMGK02TWhaPYI=; b=s1KSxyjBnftOBMEz9bTCm9KxhzZPMLVd4m6QWbCkFtTKtab2URexxttH2Wr7RPBKMd i4LzAj6DSrGojFywLyWS6vrRMI60+ygtUmuXxTEDfXSklaGZt6oeu6ivbNtBLCthLNvI 9ef58ArY5r1kzSaC+MCK2Oay69wxlsxPR8aEpCNwL4KEAQttyz0LthOHVSpgU716ueDi 2DlhIpnnsu536xxn0QrD+MTq7Vpx135WinK9Re4BH7xIQqtMRhRSOiLhPKMphuOMRLAE DHR8bBna27drlBoZvadMrqibqOrkGV79cjiz78YaENaGxTXoDH/iBjaUKeCKX/2gK0jm x8/A== X-Gm-Message-State: APjAAAVnzSqwUicpBtzNUlghIMFj+8yqSrWnkvO6Pm6vBNnRfLxCRsOG xRteUOb+B+Q/gaH03l4RYjRC3w== X-Google-Smtp-Source: APXvYqxBCz/RGzHXqMGg+UqQdt1FKzjwr4xjT+V51b+Hm23Ljn0PARusbNY2zOgAv7oXSEfUA81/Qw== X-Received: by 2002:a17:902:8f8a:: with SMTP id z10mr27668871plo.169.1580785019903; Mon, 03 Feb 2020 18:56:59 -0800 (PST) Received: from tigerii.tok.corp.google.com ([2401:fa00:8f:203:5bbb:c872:f2b1:f53b]) by smtp.gmail.com with ESMTPSA id e1sm22491971pfl.98.2020.02.03.18.56.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Feb 2020 18:56:59 -0800 (PST) From: Sergey Senozhatsky To: Hans Verkuil , Tomasz Figa , Mauro Carvalho Chehab , Kyungmin Park , Marek Szyprowski Cc: Sakari Ailus , Laurent Pinchart , Pawel Osciak , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: [RFC][PATCHv2 03/12] videobuf2: add V4L2_FLAG_MEMORY_NON_CONSISTENT flag Date: Tue, 4 Feb 2020 11:56:32 +0900 Message-Id: <20200204025641.218376-4-senozhatsky@chromium.org> X-Mailer: git-send-email 2.25.0.341.g760bfbb309-goog In-Reply-To: <20200204025641.218376-1-senozhatsky@chromium.org> References: <20200204025641.218376-1-senozhatsky@chromium.org> MIME-Version: 1.0 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org By setting or clearing V4L2_FLAG_MEMORY_NON_CONSISTENT flag user-space should be able to set or clear queue's NON_CONSISTENT ->dma_attrs. Queue's ->dma_attrs are passed to the underlying allocator in __vb2_buf_mem_alloc(), so thus user-space is able to request vb2 buffer's memory to be either consistent (coherent) or non-consistent. Change-Id: Ib333081c482e23c9a89386078293e19c3fd59076 Signed-off-by: Sergey Senozhatsky --- Documentation/media/uapi/v4l/buffer.rst | 27 +++++++++++++++++++++++++ include/uapi/linux/videodev2.h | 2 ++ 2 files changed, 29 insertions(+) diff --git a/Documentation/media/uapi/v4l/buffer.rst b/Documentation/media/uapi/v4l/buffer.rst index 9149b57728e5..af007daf0591 100644 --- a/Documentation/media/uapi/v4l/buffer.rst +++ b/Documentation/media/uapi/v4l/buffer.rst @@ -705,6 +705,33 @@ Buffer Flags .. c:type:: v4l2_memory +Memory Consistency Flags +======================== + +.. tabularcolumns:: |p{7.0cm}|p{2.2cm}|p{8.3cm}| + +.. cssclass:: longtable + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + :widths: 3 1 4 + + * .. _`V4L2_FLAG_MEMORY_NON_CONSISTENT`: + + - ``V4L2_FLAG_MEMORY_NON_CONSISTENT`` + - 0x00000001 + - vb2 buffer is allocated either in consistent (it will be automatically + coherent between CPU and bus) or non-consistent memory. The latter + can provide performance gains, for instance CPU cache sync/flush + operations can be avoided if the buffer is accesed by the corresponding + device only and CPU does not read/write to/from that buffer. However, + this requires extra care from the driver -- it must guarantee memory + consistency by issuing cache flush/sync when consistency is needed. + If this flag is set V4L2 will attempt to allocate vb2 buffer in + non-consistent memory. This flag is ignored if queue does not report + :ret:`V4L2_BUF_CAP_SUPPORTS_CACHE_HINTS` capability. + enum v4l2_memory ================ diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index 5f9357dcb060..72efc1c544cd 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -189,6 +189,8 @@ enum v4l2_memory { V4L2_MEMORY_DMABUF = 4, }; +#define V4L2_FLAG_MEMORY_NON_CONSISTENT (1 << 0) + /* see also http://vektor.theorem.ca/graphics/ycbcr/ */ enum v4l2_colorspace { /*