339 lines
45 KiB
HTML
339 lines
45 KiB
HTML
|
<!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh-cn" lang="zh-cn" data-whc_version="27.0">
|
|||
|
|
<head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/><meta name="viewport" content="width=device-width, initial-scale=1.0"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><meta name="description" content="本模块源代码在内核目录 linux-5.4/drivers/media/platform/artinchip 下，目录结构如下： drivers/media/platform/artinchip/ ├── aic_buf.c // 和 buf 管理相关的处理代码 ├── aic_dvp.c // DVP 驱动的初始化入口，主要实现了 probe、Notifier 接口 ├── aic_dvp.h ..."/><meta name="DC.rights.owner" content="(C) 版权 2025"/><meta name="copyright" content="(C) 版权 2025"/><meta name="generator" content="DITA-OT"/><meta name="DC.type" content="concept"/><meta name="DC.relation" content="../../../topics/sdk/dvp/dvp_user_guide.html"/><meta name="DC.relation" content="../../../topics/sdk/dvp/dvp_test.html"/><meta name="DC.relation" content="../../../topics/sdk/dvp/dvp_key_procedure.html"/><meta name="DC.relation" content="../../../topics/sdk/dvp/dvp_key_procedure.html"/><meta name="DC.relation" content="../../../topics/sdk/dvp/dvp_data_struct.html"/><meta name="DC.relation" content="../../../topics/sdk/dvp/dvp_interface.html"/><meta name="DC.relation" content="../../../topics/sdk/dvp/dvp_demo.html"/><meta name="DC.contributor" content="yan.wang"/><meta name="DC.contributor" content="yan.wang"/><meta name="DC.date.modified" content="2024-01-15"/><meta name="DC.format" content="HTML5"/><meta name="DC.identifier" content="dvp_design_intro"/><meta name="DC.language" content="zh-CN"/><title>设计说明</title><!-- Generated with build number 2024112209. --><meta name="wh-path2root" content="../../../"/><meta name="wh-toc-id" content="dvp_design_intro-d4445e5274"/><meta name="wh-source-relpath" content="topics/sdk/dvp/dvp_design.dita"/><meta name="wh-out-relpath" content="topics/sdk/dvp/dvp_design.html"/>
|
|||
|
|
|
|||
|
|
<link rel="stylesheet" type="text/css" href="../../../webhelp/app/commons.css?buildId=2024112209"/>
|
|||
|
|
<link rel="stylesheet" type="text/css" href="../../../webhelp/app/topic.css?buildId=2024112209"/>
|
|||
|
|
|
|||
|
|
<script src="../../../webhelp/app/options/properties.js?buildId=20250123154945"></script>
|
|||
|
|
<script src="../../../webhelp/app/localization/strings.js?buildId=2024112209"></script>
|
|||
|
|
<script src="../../../webhelp/app/search/index/keywords.js?buildId=20250123154945"></script>
|
|||
|
|
<script defer="defer" src="../../../webhelp/app/commons.js?buildId=2024112209"></script>
|
|||
|
|
<script defer="defer" src="../../../webhelp/app/topic.js?buildId=2024112209"></script>
|
|||
|
|
<link rel="stylesheet" type="text/css" href="../../../webhelp/template/aic-styles-web.css?buildId=2024112209"/><link rel="stylesheet" type="text/css" href="../../../webhelp/template/notes.css?buildId=2024112209"/><link rel="stylesheet" type="text/css" href="../../../webhelp/template/aic-common.css?buildId=2024112209"/><link rel="stylesheet" type="text/css" href="../../../webhelp/template/aic-images.css?buildId=2024112209"/><link rel="stylesheet" type="text/css" href="../../../webhelp/template/footnote.css?buildId=2024112209"/><link rel="stylesheet" type="text/css" href="../../../webhelp/template/aic-web-watermark.css?buildId=2024112209"/><link rel="stylesheet" type="text/css" href="../../../webhelp/template/topic-body-list.css?buildId=2024112209"/></head>
|
|||
|
|
|
|||
|
|
<body id="dvp_design_intro" class="wh_topic_page frmBody">
|
|||
|
|
<a href="#wh_topic_body" class="sr-only sr-only-focusable">
|
|||
|
|
跳转到主要内容
|
|||
|
|
</a>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<header class="navbar navbar-default wh_header">
|
|||
|
|
<div class="container-fluid">
|
|||
|
|
<div class="wh_header_flex_container navbar-nav navbar-expand-md navbar-dark">
|
|||
|
|
<div class="wh_logo_and_publication_title_container">
|
|||
|
|
<div class="wh_logo_and_publication_title">
|
|||
|
|
|
|||
|
|
<a href="http://www.artinchip.com" class=" wh_logo d-none d-sm-block "><img src="../../../company-logo-white.png" alt=" Linux SDK 使用指南 SDK 指南文件 "/></a>
|
|||
|
|
<div class=" wh_publication_title "><a href="../../../index.html"><span class="booktitle"> <span class="ph mainbooktitle">Linux SDK 使用指南</span> <span class="ph booktitlealt">SDK 指南文件</span> </span></a></div>
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
<div class="wh_top_menu_and_indexterms_link collapse navbar-collapse" id="wh_top_menu_and_indexterms_link">
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</header>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<div class=" wh_search_input navbar-form wh_topic_page_search search " role="form">
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<form id="searchForm" method="get" role="search" action="../../../search.html"><div><input type="search" placeholder="搜索 " class="wh_search_textfield" id="textToSearch" name="searchQuery" aria-label="搜索查询" required="required"/><button type="submit" class="wh_search_button" aria-label="搜索"><span class="search_input_text">搜索</span></button></div></form>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
<div class="container-fluid" id="wh_topic_container">
|
|||
|
|
<div class="row">
|
|||
|
|
|
|||
|
|
<nav class="wh_tools d-print-none navbar-expand-md" aria-label="Tools">
|
|||
|
|
|
|||
|
|
<div data-tooltip-position="bottom" class=" wh_breadcrumb "><ol class="d-print-none"><li><span class="home"><a href="../../../index.html"><span>主页</span></a></span></li><li><div class="topicref" data-id="id"><div class="title"><a href="../../../topics/sdk/chapter-advanced-app.html">高级应用</a><div class="wh-tooltip"><p class="shortdesc">系统、存储、多媒体、接口、安全等模块的详细配置和设计说明。</p></div></div></div></li><li><div class="topicref" data-id="concept_mcc_32s_nbc"><div class="title"><a href="../../../topics/chapter-title/chapter-multi-media-sdk.html">多媒体</a><div class="wh-tooltip"><p class="shortdesc">GE、VE、Display、DVP、MPP、MPP 播放器等多媒体模块的介绍和使用说明。</p></div></div></div></li><li><div class="topicref" data-id="concept_h4d_fwt_tzb"><div class="title"><a href="../../../topics/sdk/dvp/dvp_user_guide.html">DVP 使用指南</a></div></div></li><li class="active"><div class="topicref" data-id="dvp_design_intro"><div class="title"><a href="../../../topics/sdk/dvp/dvp_design.html">设计说明</a></div></div></li></ol></div>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<div class="wh_right_tools">
|
|||
|
|
<button class="wh_hide_highlight" aria-label="切换搜索突出显示" title="切换搜索突出显示"></button>
|
|||
|
|
<button class="webhelp_expand_collapse_sections" data-next-state="collapsed" aria-label="折叠截面" title="折叠截面"></button>
|
|||
|
|
<div class=" wh_navigation_links "><span id="topic_navigation_links" class="navheader">
|
|||
|
|
|
|||
|
|
<span class="navprev"><a class="- topic/link link" href="../../../topics/sdk/dvp/dvp_test.html" title="测试指南" aria-label="上一主题: 测试指南" rel="prev"></a></span>
|
|||
|
|
<span class="navnext"><a class="- topic/link link" href="../../../topics/sdk/dvp/dvp_key_procedure.html" title="关键流程设计" aria-label="下一主题: 关键流程设计" rel="next"></a></span> </span></div>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<div class=" wh_print_link print d-none d-md-inline-block "><button onClick="window.print()" title="打印此页" aria-label="打印此页"></button></div>
|
|||
|
|
|
|||
|
|
<button type="button" id="wh_toc_button" class="custom-toggler navbar-toggler collapsed wh_toggle_button navbar-light" aria-expanded="false" aria-label="Toggle publishing table of content" aria-controls="wh_publication_toc">
|
|||
|
|
<span class="navbar-toggler-icon"></span>
|
|||
|
|
</button>
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
</nav>
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<div class="wh_content_area">
|
|||
|
|
<div class="row">
|
|||
|
|
|
|||
|
|
<nav id="wh_publication_toc" class="col-lg-3 col-md-3 col-sm-12 d-md-block d-none d-print-none" aria-label="Table of Contents Container">
|
|||
|
|
<div id="wh_publication_toc_content">
|
|||
|
|
|
|||
|
|
<div class=" wh_publication_toc " data-tooltip-position="right"><span class="expand-button-action-labels"><span id="button-expand-action" role="button" aria-label="Expand"></span><span id="button-collapse-action" role="button" aria-label="Collapse"></span><span id="button-pending-action" role="button" aria-label="Pending"></span></span><ul role="tree" aria-label="Table of Contents"><li role="treeitem"><div data-tocid="revinfo_linux-d4445e1079" class="topicref" data-id="revinfo_linux" data-state="leaf"><span role="button" class="wh-expand-btn"></span><div class="title"><a href="../../../topics/revinfo/revinfo_linux.html" id="revinfo_linux-d4445e1079-link">修订记录</a></div></div></li><li role="treeitem" aria-expanded="false"><div data-tocid="id-d4445e1096" class="topicref" data-id="id" data-state="not-ready"><span role="button" tabindex="0" aria-labelledby="button-expand-action id-d4445e1096-link" class="wh-expand-btn"></span><div class="title"><a href="../../../topics/sdk/env/sdk-compile.html" id="id-d4445e1096-link">SDK 编译</a><div class="wh-tooltip"><p class="shortdesc">介绍不同编译环境下 SDK 的详细编译流程。</p></div></div></div></li><li role="treeitem" aria-expanded="false"><div data-tocid="tocId-d4445e1240" class="topicref" data-state="not-ready"><span role="button" tabindex="0" aria-labelledby="button-expand-action tocId-d4445e1240-link" class="wh-expand-btn"></span><div class="title"><a href="../../../topics/sdk/advanced/lb_usage_commands.html" id="tocId-d4445e1240-link">使用指南</a></div></div></li><li role="treeitem" aria-expanded="false"><div data-tocid="concept_rcx_czh_pzb-d4445e1360" class="topicref" data-id="concept_rcx_czh_pzb" data-state="not-ready"><span role="button" tabindex="0" aria-labelledby="button-expand-action concept_rcx_czh_pzb-d4445e1360-link" class="wh-expand-btn"></span><div class="title"><a href="../../../topics/sdk/chapter-app.html" id="concept_rcx_czh_pzb-d4445e1360-link">应用场景</a><div class="wh-tooltip"><p class="shortdesc">描述了 SDK 在不同应用场景中的配置和使用，包括系统更新、OTA、安全方案等。</p></div></div></div></li><li role="treeitem" aria-expanded="false"><div data-tocid="id-d4445e1678" class="topicref" data-id="id" data-state="not-ready"><span role="button" tabindex="0" aria-labelledby="button-expand-action id-d4445e1678-link" class="wh-expand-btn"></span><div class="title"><a href="../../../topics/sdk/peripheral/peripheral-intro.html" id="id-d4445e1678-link">外设移植</a><div class="wh-tooltip"><p class="shortdesc"><span class="ph">触摸屏、显示器、WIFI 模块、按键</span>等外设的介绍和使用说明。</p></div></div></div></li><li role="treeitem" aria-expanded="false"><div data-tocid="id-d4445e1964" class="topicref" data-id="id" data-state="not-ready"><span role="button" tabindex="0" aria-labelledby="button-expand-action id-d4445e1964-link" class="wh-expand-btn"></span><div class="title"><a href="../../../topics/sdk/bringup/chapter-bringup.html" id="id-d4445e1964-link">BringUp</a><div class="wh-tooltip"><p class="shortdesc">在硬件上电后快速初始化系统，为操作系统的启动准备好必要的硬件环境。</p></div></div></div></li><li role="treeitem" aria-expanded="true"><div data-tocid="id-d4445e2153" class="topicref" data-id="id" data-state="expanded"><span role="button" tabindex="0" aria-labelledby="button-collapse-action id-d4445e2153-link" class="wh-expand-btn"></span><div class="title"><a href="../../../topics/sdk/chapter-advanced-app.html" id="id-d4445e2153-link">高级应用</a><div class="wh-tooltip"><p class="shortdesc">系统、存储、多媒体、接口、安全等模块的详细配置和设计说明。</p></div></div></div><ul role="group" class="navbar-nav nav-list"><li role="treeitem" aria-expanded="false"><div data-tocid="uBoot-d4445e2170" class="topicref" data-id="uBoot" data-state="not-ready"><span role="button" tabindex="0" aria-labelledby="button-expand-action uBoot-d4445e2170-link" class="wh-expand-btn"></span><div class="titl
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
</nav>
|
|||
|
|
|
|||
|
|
|
|||
|
|
<div class="col-lg-7 col-md-9 col-sm-12" id="wh_topic_body">
|
|||
|
|
<button id="wh_close_publication_toc_button" class="close-toc-button d-none" aria-label="Toggle publishing table of content" aria-controls="wh_publication_toc" aria-expanded="true">
|
|||
|
|
<span class="close-toc-icon-container">
|
|||
|
|
<span class="close-toc-icon"></span>
|
|||
|
|
</span>
|
|||
|
|
</button>
|
|||
|
|
<button id="wh_close_topic_toc_button" class="close-toc-button d-none" aria-label="Toggle topic table of content" aria-controls="wh_topic_toc" aria-expanded="true">
|
|||
|
|
<span class="close-toc-icon-container">
|
|||
|
|
<span class="close-toc-icon"></span>
|
|||
|
|
</span>
|
|||
|
|
</button>
|
|||
|
|
|
|||
|
|
<div class=" wh_topic_content body "><main role="main"><article class="- topic/topic concept/concept topic concept" role="article" aria-labelledby="ariaid-title1">
|
|||
|
|
<span class="edit-link" style="font-size:12px; opacity:0.6; text-align:right; vertical-align:middle"><a target="_blank" title="Edit this document" href="http://172.16.35.88/tasks/jdssno1uvvbf2mltu9kb9v3if05d5gopuakboe8hlud18rma/edit/F:/aicdita/aicdita-cn/topics/sdk/dvp/dvp_design.dita">Edit online</a></span><h1 class="- topic/title title topictitle1" id="ariaid-title1">设计说明</h1>
|
|||
|
|
|
|||
|
|
<div class="date inPage">15 Jan 2024</div><div style="color: gray;">
|
|||
|
|
Read time: 4 minute(s)
|
|||
|
|
</div>
|
|||
|
|
<div class="- topic/body concept/conbody body conbody">
|
|||
|
|
<div class="- topic/p p" data-ofbid="d154069e33__20250123155215">本模块源代码在内核目录
|
|||
|
|
<span class="+ topic/ph sw-d/filepath ph filepath">linux-5.4/drivers/media/platform/artinchip</span>下，目录结构如下：<pre class="+ topic/pre pr-d/codeblock pre codeblock language-c" id="dvp_design_intro__pre_lg2_vzg_d1c" data-ofbid="dvp_design_intro__pre_lg2_vzg_d1c"><code>drivers/media/platform/artinchip/
|
|||
|
|
├── aic_buf.c <em class="hl-comment">// 和 buf 管理相关的处理代码</em>
|
|||
|
|
├── aic_dvp.c <em class="hl-comment">// DVP 驱动的初始化入口，主要实现了 probe、Notifier 接口</em>
|
|||
|
|
├── aic_dvp.h <em class="hl-comment">// DVP 驱动共用的头文件，其中定义了寄存器、共用数据结构、全局函数等</em>
|
|||
|
|
├── aic_dvp_hw.c <em class="hl-comment">// 对寄存器的访问封装</em>
|
|||
|
|
├── aic_video.c <em class="hl-comment">// 和 L2 框架强相关的一些接口定义，如 ops、ioctl_ops 的接口实现等</em>
|
|||
|
|
├── Kconfig
|
|||
|
|
└── Makefile</code></pre></div>
|
|||
|
|
<section class="- topic/section section" id="dvp_design_intro__section_wwl_b1h_d1c" data-ofbid="dvp_design_intro__section_wwl_b1h_d1c"><h2 class="- topic/title title sectiontitle">V4L2 软件框架</h2>
|
|||
|
|
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e46__20250123155215">Linux 中的 V4L2 框架是一个专门为视频输入输出设备而设计的成熟方案，DVP 驱动需要基于 V4L2。</p>
|
|||
|
|
<div class="- topic/p p" data-ofbid="d154069e49__20250123155215">
|
|||
|
|
<figure class="- topic/fig fig fignone" id="dvp_design_intro__fig_rkz_41h_d1c" data-ofbid="dvp_design_intro__fig_rkz_41h_d1c">
|
|||
|
|
|
|||
|
|
<br/><div class="imagecenter"><img class="- topic/image image imagecenter" id="dvp_design_intro__image_xwl_b1h_d1c" src="../../../images/dvp/v4l2_system.jpg" alt="v4l2_system"/></div><br/>
|
|||
|
|
<figcaption data-caption-side="bottom" class="- topic/title title figcapcenter"><span class="figtitleprefix fig--title-label">图<span class="fig--title-label-number"> 1</span><span class="fig--title-label-punctuation">. </span></span><span class="fig--title">Linux V4L2 子系统架构图</span></figcaption></figure>
|
|||
|
|
</div>
|
|||
|
|
<ol class="- topic/ol ol" id="dvp_design_intro__ol_ywl_b1h_d1c" data-ofbid="dvp_design_intro__ol_ywl_b1h_d1c">
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e66__20250123155215">
|
|||
|
|
<div class="- topic/p p" data-ofbid="d154069e68__20250123155215">V4L2，Video For Linux 第 2 版，最早出现在 1998 年，一个针对无线广播（收音机）、视频捕获、视频输出设备的通用框架，源码目录
|
|||
|
|
<span class="+ topic/ph sw-d/filepath ph filepath">drivers/media/v4l2-core</span>。V4L2 中支持的 5 大类接口设备：<ul class="- topic/ul ul" id="dvp_design_intro__ul_axl_b1h_d1c" data-ofbid="dvp_design_intro__ul_axl_b1h_d1c">
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e75__20250123155215">
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e77__20250123155215">Video capture interface：影像捕获接口。</p>
|
|||
|
|
</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e81__20250123155215">
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e83__20250123155215">Video output interface：视频输出接口，主要用于电视信号类。</p>
|
|||
|
|
</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e87__20250123155215">
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e89__20250123155215">Video overlay interface：视频覆盖接口，方便视频显示设备直接从捕获设备上获取数据。</p>
|
|||
|
|
</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e93__20250123155215">
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e95__20250123155215">VBI interface：垂直消隐接口，可提供垂直消隐区的数据接入，包括 raw 和 sliced 两种。</p>
|
|||
|
|
</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e99__20250123155215">
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e101__20250123155215">Radio interface：广播接口，主要是从 AM 或 FM 调谐器中获取音频数据。</p>
|
|||
|
|
</li>
|
|||
|
|
</ul></div>
|
|||
|
|
</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e107__20250123155215">
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e109__20250123155215">V4L2 为用户空间提供了字符设备的通用接口，设备节点 /dev/videoX，主设备号 81，次设备号的分配跟设备类型有关，规则定义如下：</p>
|
|||
|
|
<div class="table-container"><table class="- topic/table table frame-all" id="dvp_design_intro__table_dxl_b1h_d1c" data-ofbid="dvp_design_intro__table_dxl_b1h_d1c" data-cols="2"><caption></caption><colgroup><col style="width:50%"/><col style="width:50%"/></colgroup><thead class="- topic/thead thead">
|
|||
|
|
<tr class="- topic/row">
|
|||
|
|
<th class="- topic/entry entry colsep-1 rowsep-1" id="dvp_design_intro__table_dxl_b1h_d1c__entry__1">设备类型</th>
|
|||
|
|
<th class="- topic/entry entry colsep-0 rowsep-1" id="dvp_design_intro__table_dxl_b1h_d1c__entry__2">次设备号</th>
|
|||
|
|
</tr>
|
|||
|
|
</thead><tbody class="- topic/tbody tbody">
|
|||
|
|
<tr class="- topic/row">
|
|||
|
|
<td class="- topic/entry entry colsep-1 rowsep-1" headers="dvp_design_intro__table_dxl_b1h_d1c__entry__1">视频设备</td>
|
|||
|
|
<td class="- topic/entry entry colsep-0 rowsep-1" headers="dvp_design_intro__table_dxl_b1h_d1c__entry__2">0~63</td>
|
|||
|
|
</tr>
|
|||
|
|
<tr class="- topic/row">
|
|||
|
|
<td class="- topic/entry entry colsep-1 rowsep-1" headers="dvp_design_intro__table_dxl_b1h_d1c__entry__1">Radio 设备</td>
|
|||
|
|
<td class="- topic/entry entry colsep-0 rowsep-1" headers="dvp_design_intro__table_dxl_b1h_d1c__entry__2">64~127</td>
|
|||
|
|
</tr>
|
|||
|
|
<tr class="- topic/row">
|
|||
|
|
<td class="- topic/entry entry colsep-1 rowsep-1" headers="dvp_design_intro__table_dxl_b1h_d1c__entry__1">Teletext 设备</td>
|
|||
|
|
<td class="- topic/entry entry colsep-0 rowsep-1" headers="dvp_design_intro__table_dxl_b1h_d1c__entry__2">192~233</td>
|
|||
|
|
</tr>
|
|||
|
|
<tr class="- topic/row">
|
|||
|
|
<td class="- topic/entry entry colsep-1 rowsep-0" headers="dvp_design_intro__table_dxl_b1h_d1c__entry__1">VBI 设备</td>
|
|||
|
|
<td class="- topic/entry entry colsep-0 rowsep-0" headers="dvp_design_intro__table_dxl_b1h_d1c__entry__2">224~255</td>
|
|||
|
|
</tr>
|
|||
|
|
</tbody></table></div>
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e173__20250123155215">用户态 APP 通过 ioctl 控制 video 设备，通过 mmap 进行内存映射。在/dev 目录中会产生 videoX、radioX 和 vbiX
|
|||
|
|
设备节点。</p>
|
|||
|
|
</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e177__20250123155215">在 V4L2 框架中，将每一个 Sensor、DVP 硬件设备都看作一个 subdev，相应的有一个字符设备节点
|
|||
|
|
/dev/v4l-subdevX，用户态通过这些节点的 ioctl 接口可以完成 subdev 的格式协商、时序配置等功能。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e180__20250123155215">Notifier 子模块是为了解决多个设备之间的初始化顺序、以及媒体流对接的匹配检查，如 DVP 需要等 Sensor 初始化完成后，才能去真正完成 video
|
|||
|
|
device 的注册。可见，DVP 和 Sensor 要有一个绑定的关系，这个关系是由 DTS 中的 remote-endpoint 来指定的。Notifier
|
|||
|
|
会调用 Fwnode 系列接口来解析和获取 remote-endpoint 的属性字段。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e183__20250123155215">为了进行数据流的管理，V4L2 维护了一个 device 链表，每一个 video device、V4L2 device、V4L2-subdev 都是一个
|
|||
|
|
Media device 实例，这些 Media device 在数据结构的设计上第一个成员变量都是一个 struct media_entity，其中有
|
|||
|
|
list_head 成员，借此互相链接起来。见下一节详述。</li>
|
|||
|
|
</ol>
|
|||
|
|
</section>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<section class="- topic/section section" id="dvp_design_intro__section_cyl_b1h_d1c" data-ofbid="dvp_design_intro__section_cyl_b1h_d1c"><h2 class="- topic/title title sectiontitle">V4L2 的 Buf 队列管理</h2>
|
|||
|
|
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e193__20250123155215">V4L2 的 Buffer 管理由 videobuf 子模块实现，从源头看分为两种方式的 Buffer：</p>
|
|||
|
|
<ol class="- topic/ol ol" id="dvp_design_intro__ol_dyl_b1h_d1c" data-ofbid="dvp_design_intro__ol_dyl_b1h_d1c">
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e198__20250123155215">驱动申请 Buffer<p class="- topic/p p" data-ofbid="d154069e200__20250123155215">用户态通过 VIDIOC_REQBUFS ioctl 命令触发 Buffer 申请，然后使用 mmap 接口来获取用户态的
|
|||
|
|
Buffer 地址。这种方式，Buffer 个数一般有个最大值 32 VIDEO_MAX_FRAME。</p></li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e203__20250123155215">用户态申请 Buffer<p class="- topic/p p" data-ofbid="d154069e205__20250123155215">用户态根据实际需要知道要申请多少 Buffer，然后借助其他机制（可以是 dma-buf）在用户态完成
|
|||
|
|
Buffer（当然必须是物理连续的）申请，并将物理地址告诉 Video 驱动。</p></li>
|
|||
|
|
</ol>
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e209__20250123155215">按照 Buffer 的物理连续，又可以分为三种情况：（详见
|
|||
|
|
<span class="+ topic/ph sw-d/filepath ph filepath">Documentationmediakapiv4l2-videobuf.rst</span>）</p>
|
|||
|
|
<ol class="- topic/ol ol" id="dvp_design_intro__ol_gyl_b1h_d1c" data-ofbid="dvp_design_intro__ol_gyl_b1h_d1c">
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e217__20250123155215">物理连续、不连续的 Buffer 混用<p class="- topic/p p" data-ofbid="d154069e219__20250123155215">几乎所有用户空间的 Buffer 都属于这种情况，这样最大可能的发挥虚拟内存管理的灵活性。缺点也很明显，这些
|
|||
|
|
Buffer 给硬件的话需要有支持 scatter 的 DMA。</p></li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e222__20250123155215">物理不连续、虚拟地址连续的 Buffer<p class="- topic/p p" data-ofbid="d154069e224__20250123155215">它们由 vmalloc()分配，也用于支持 scatter 接口的 DMA 硬件。</p></li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e227__20250123155215">物理连续的 Buffer<p class="- topic/p p" data-ofbid="d154069e229__20250123155215">非常适合 DMA 类硬件的访问。</p></li>
|
|||
|
|
</ol>
|
|||
|
|
<div class="- topic/note note note note_note" id="dvp_design_intro__note_y3h_gch_d1c" data-ofbid="dvp_design_intro__note_y3h_gch_d1c"><span class="note__title">注：</span> <div class="note__body">
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e236__20250123155215">驱动开发者必须三选一，对于我们的 DVP 模块来说，要选择 3。并且底层用到 dma-buf。</p>
|
|||
|
|
</div></div>
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e240__20250123155215">V4L 第二版不再支持 Overlay 类型，而 V4L 第一版不支持 DMABUF 类型。</p>
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e243__20250123155215">V4L2 在数据流传输的时候需要多个 Buf 切换，通过 struct vb2_queue 结构中的 Qbuf 两个 Buf 队列来管理，DVP 驱动中还需要维护一个
|
|||
|
|
buf_list 来配合 DVP 控制器的地址更新。整个 Buf 流转的过程如下图：</p>
|
|||
|
|
<div class="- topic/p p" data-ofbid="d154069e246__20250123155215">
|
|||
|
|
<figure class="- topic/fig fig fignone" id="dvp_design_intro__fig_npb_d1h_d1c" data-ofbid="dvp_design_intro__fig_npb_d1h_d1c">
|
|||
|
|
|
|||
|
|
<br/><div class="imagecenter"><img class="- topic/image image imagecenter" id="dvp_design_intro__image_kyl_b1h_d1c" src="../../../images/dvp/dvp_buf_list.jpg" alt="dvp_buf_list"/></div><br/>
|
|||
|
|
<figcaption data-caption-side="bottom" class="- topic/title title figcapcenter"><span class="figtitleprefix fig--title-label">图<span class="fig--title-label-number"> 2</span><span class="fig--title-label-punctuation">. </span></span><span class="fig--title">DVP 驱动中的 Buf 队列管理</span></figcaption></figure>
|
|||
|
|
</div>
|
|||
|
|
<ul class="- topic/ul ul" id="dvp_design_intro__ul_lyl_b1h_d1c" data-ofbid="dvp_design_intro__ul_lyl_b1h_d1c">
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e263__20250123155215">Qbuf 队列（在代码中见 struct vb2_queue->queued_list）：是一些空闲 Buf，等待 Sensor 的数据到来后，DVP
|
|||
|
|
驱动会从这个队列中找可用 Buf 来保存下一帧数据。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e266__20250123155215">DQbuf 队列（在代码中见 struct vb2_queue->done_list）：是一些填了视频数据的
|
|||
|
|
Buf，等待用户来处理这些数据，一般用户处理完后需要将 Buf 还给驱动，也就是还给 Qbuf。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e269__20250123155215">从 Qbuf 和 DQbuf 来的 buf 格式是 buffer，其中没有字段可以保存物理地址（DVP 控制器需要），同时还需要为每个 buf
|
|||
|
|
记录一个是否正在被 DVP 使用的状态，所以 DVP 驱动中定义了基于 vb2_buffer 结构的封装 buffer，并且维护一个和 Qbuf
|
|||
|
|
几乎同步的队列。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e272__20250123155215">从图中的流转过程看，运行期间，在某一时刻，DVP 需要使用一个 Buf，APP 需要使用一个 Buf，QBuf 需要有一个 Buf 在等待（否则 DVP 的
|
|||
|
|
done 中断来了后发现没有等待的 Qbuf 会发生丢帧），一共至少要有 3 个 Buf。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e275__20250123155215">以 YUV422 格式计算，有两个 plane，在 L2 框架中这一组 plane 算一个 Buf，3 个 Buf 就需要申请 6 个
|
|||
|
|
plane，<code class="+ topic/ph pr-d/codeph ph codeph">总大小 = 长 * 宽 * 2 * 3</code>。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e282__20250123155215">DVP 驱动中需要定义一个 queue 实例，Video device 中会有一个指针*queue 指向该实例。</li>
|
|||
|
|
</ul>
|
|||
|
|
</section>
|
|||
|
|
<section class="- topic/section section" id="dvp_design_intro__section_myl_b1h_d1c" data-ofbid="dvp_design_intro__section_myl_b1h_d1c"><h2 class="- topic/title title sectiontitle">DVP 驱动的子模块结构</h2>
|
|||
|
|
|
|||
|
|
<p class="- topic/p p" data-ofbid="d154069e292__20250123155215">基于以上对 V4L2 框架的分析，DVP 驱动内部可以分为以下 5 个子模块：</p>
|
|||
|
|
<div class="- topic/p p" data-ofbid="d154069e295__20250123155215">
|
|||
|
|
<figure class="- topic/fig fig fignone" id="dvp_design_intro__fig_bzw_b1h_d1c" data-ofbid="dvp_design_intro__fig_bzw_b1h_d1c">
|
|||
|
|
|
|||
|
|
<br/><div class="imagecenter"><img class="- topic/image image imagecenter" id="dvp_design_intro__image_nyl_b1h_d1c" src="../../../images/dvp/dvp_drv_structure.jpg" alt="dvp_drv_structure"/></div><br/>
|
|||
|
|
<figcaption data-caption-side="bottom" class="- topic/title title figcapcenter"><span class="figtitleprefix fig--title-label">图<span class="fig--title-label-number"> 3</span><span class="fig--title-label-punctuation">. </span></span><span class="fig--title">DVP 驱动的子模块结构</span></figcaption></figure>
|
|||
|
|
</div>
|
|||
|
|
<ul class="- topic/ul ul" id="dvp_design_intro__ul_oyl_b1h_d1c" data-ofbid="dvp_design_intro__ul_oyl_b1h_d1c">
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e312__20250123155215">Video Dvice 管理，主要实现和 device 相关的注册、ioctl 处理。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e315__20250123155215">Notifier 管理，主要处理和 Sensor 设备的初始化次序的依赖关系。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e318__20250123155215">Buf 管理，主要实现 Buf 的入队、出队，以及在中断响应时切换 DVP 控制器的输出地址等。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e321__20250123155215">Subdev 管理，主要实现输入格式相关的接口。</li>
|
|||
|
|
<li class="- topic/li li" data-ofbid="d154069e324__20250123155215">寄存器访问，封装了对 DVP 控制器寄存器的读写访问。</li>
|
|||
|
|
</ul>
|
|||
|
|
</section>
|
|||
|
|
</div>
|
|||
|
|
</article></main></div>
|
|||
|
|
|
|||
|
|
<div class=" wh_child_links d-print-none "><nav aria-label="Child Links" role="navigation" class="- topic/related-links related-links"><ul class="ullinks"><li class="- topic/link link ulchildlink"><strong><a href="../../../topics/sdk/dvp/dvp_key_procedure.html">关键流程设计</a></strong></li><li class="- topic/link link ulchildlink"><strong><a href="../../../topics/sdk/dvp/dvp_data_struct.html">数据结构设计</a></strong></li><li class="- topic/link link ulchildlink"><strong><a href="../../../topics/sdk/dvp/dvp_interface.html">接口设计</a></strong></li><li class="- topic/link link ulchildlink"><strong><a href="../../../topics/sdk/dvp/dvp_demo.html">APP Demo</a></strong></li></ul></nav></div>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
<nav role="navigation" id="wh_topic_toc" aria-label="On this page" class="col-lg-2 d-none d-lg-block navbar d-print-none">
|
|||
|
|
<div id="wh_topic_toc_content">
|
|||
|
|
|
|||
|
|
<div class=" wh_topic_toc "><div class="wh_topic_label">在本页上</div><ul><li class="section-item"><div class="section-title"><a href="#dvp_design_intro__section_wwl_b1h_d1c" data-tocid="dvp_design_intro__section_wwl_b1h_d1c">V4L2 软件框架</a></div></li><li class="section-item"><div class="section-title"><a href="#dvp_design_intro__section_cyl_b1h_d1c" data-tocid="dvp_design_intro__section_cyl_b1h_d1c">V4L2 的 Buf 队列管理</a></div></li><li class="section-item"><div class="section-title"><a href="#dvp_design_intro__section_myl_b1h_d1c" data-tocid="dvp_design_intro__section_myl_b1h_d1c">DVP 驱动的子模块结构</a></div></li></ul></div>
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
</nav>
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
</div>
|
|||
|
|
<footer class="navbar navbar-default wh_footer">
|
|||
|
|
<div class=" footer-container mx-auto ">
|
|||
|
|
<title>footer def</title>
|
|||
|
|
<style><!--
|
|||
|
|
|
|||
|
|
.p1 {
|
|||
|
|
font-family: FangZhengShuSong, Times, serif;
|
|||
|
|
}
|
|||
|
|
.p2 {
|
|||
|
|
font-family: Arial, Helvetica, sans-serif;
|
|||
|
|
}
|
|||
|
|
.p3 {
|
|||
|
|
font-family: "Lucida Console", "Courier New", monospace;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
--></style>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
<div class="webhelp.fragment.footer">
|
|||
|
|
<p class="p1">Copyright © 2019-2024 广东匠芯创科技有限公司. All rights reserved.</p>
|
|||
|
|
</div><div>
|
|||
|
|
<div class="generation_time">
|
|||
|
|
Update Time: 2025-01-23
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</footer>
|
|||
|
|
|
|||
|
|
<button id="go2top" class="d-print-none" title="返回顶部">
|
|||
|
|
<span class="oxy-icon oxy-icon-up"></span>
|
|||
|
|
</button>
|
|||
|
|
|
|||
|
|
<div id="modal_img_large" class="modal">
|
|||
|
|
<span class="close oxy-icon oxy-icon-remove"></span>
|
|||
|
|
<div id="modal_img_container"></div>
|
|||
|
|
<div id="caption"></div>
|
|||
|
|
</div>
|
|||
|
|
|
|||
|
|
|
|||
|
|
<script src="${pd}/publishing/publishing-styles-AIC-template/js/custom.js" defer="defer"></script>
|
|||
|
|
|
|||
|
|
|
|||
|
|
</body>
|
|||
|
|
</html>
|