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<section id="id1">
<h1>芯片通用移植指南<a class="headerlink" href="#id1" title="Link to this heading"></a></h1>
<p>本节主要介绍所有带 USB IP 的芯片，移植 CherryUSB 主从协议栈时的通用步骤和注意事项。在移植之前，需要 <strong>你准备好一个可以打印 helloworld 的基本工程</strong> ，默认打印使用 <cite>printf</cite>, 如果是主机模式， <strong>则需要准备好可以正常执行 os 调度的基本工程</strong>。</p>
<section id="usb-device">
<h2>USB Device 移植要点<a class="headerlink" href="#usb-device" title="Link to this heading"></a></h2>
<ul class="simple">
<li><p>拷贝 CherryUSB 源码到工程目录下，并按需添加源文件和头文件路径，头文件路径建议全部添加。其中 <cite>usbd_core.c</cite> 和 <cite>usb_dc_xxx.c</cite> 为必须添加项。而 <cite>usb_dc_xxx.c</cite> 是芯片所对应的 USB IP dcd 部分驱动，如果不知道自己芯片属于那个 USB IP，参考 <strong>port</strong> 目录下的不同 USB IP 的 readme。如果使用的 USB IP 没有支持，只能自己实现了</p></li>
<li><p>拷贝 <cite>cherryusb_config_template.h</cite> 文件到自己工程目录下，命名为 <cite>usb_config.h</cite>，并添加相应的目录头文件路径</p></li>
<li><p>实现 <cite>usb_dc_low_level_init</cite> 函数（该函数主要负责 USB 时钟、引脚、中断的初始化）。该函数可以放在你想要放的任何参与编译的 c 文件中。如何进行 USB 的时钟、引脚、中断等初始化，请自行根据你使用的芯片原厂提供的源码中进行添加。</p></li>
<li><p>在中断函数中调用 <cite>USBD_IRQHandler</cite>，并传入 <cite>busid</cite>, 如果你的 SDK 中中断入口已经存在 <cite>USBD_IRQHandler</cite> ，请更改 USB 协议栈中的名称</p></li>
<li><p>如果芯片带 cache，cache 修改参考 <a class="reference internal" href="#usb-cache"><span class="std std-ref">cache 配置修改</span></a> 章节</p></li>
<li><p>注册描述符并调用 <cite>usbd_initialize</cite>，填入 <cite>busid</cite> 和 USB IP 的 <cite>reg base</cite>， <cite>busid</cite> 从 0 开始，不能超过 <cite>CONFIG_USBDEV_MAX_BUS</cite>，可以直接使用 demo 下的 template</p></li>
</ul>
</section>
<section id="usb-host">
<h2>USB Host 移植要点<a class="headerlink" href="#usb-host" title="Link to this heading"></a></h2>
<ul class="simple">
<li><p>拷贝 CherryUSB 源码到工程目录下，并按需添加源文件和头文件路径，头文件路径建议全部添加。其中 <cite>usbh_core.c</cite> 、 <cite>usb_hc_xxx.c</cite> 以及 <strong>osal</strong> 目录下源文件（根据不同的 os 选择对应的源文件）为必须添加项。而 <cite>usb_hc_xxx.c</cite> 是芯片所对应的 USB IP hcd 部分驱动，如果不知道自己芯片属于那个 USB IP，参考 <strong>port</strong> 目录下的不同 USB IP 的 readme。如果使用的 USB IP 没有支持，只能自己实现了</p></li>
<li><p>拷贝 <cite>cherryusb_config_template.h</cite> 文件到自己工程目录下，命名为 <cite>usb_config.h</cite>，并添加相应的目录头文件路径</p></li>
<li><p>实现 <cite>usb_hc_low_level_init</cite> 函数（该函数主要负责 USB 时钟、引脚、中断的初始化）。该函数可以放在你想要放的任何参与编译的 c 文件中。如何进行 USB 的时钟、引脚、中断等初始化，请自行根据你使用的芯片原厂提供的源码中进行添加。</p></li>
<li><p>调用 <cite>usbh_initialize</cite> 并填入 <cite>busid</cite> 和 USB IP 的 <cite>reg base</cite> 还有 <cite>event_handler</cite> 可缺省为NULL， <cite>busid</cite> 从 0 开始，不能超过 <cite>CONFIG_USBHOST_MAX_BUS</cite></p></li>
<li><p>在中断函数中调用 <cite>USBH_IRQHandler</cite>，并传入 <cite>busid</cite>, 如果你的 SDK 中中断入口已经存在 <cite>USBH_IRQHandler</cite> ，请更改 USB 协议栈中的名称</p></li>
<li><p>链接脚本修改参考 <a class="reference internal" href="#usbh-link-script"><span class="std std-ref">主机链接脚本修改</span></a> 章节</p></li>
<li><p>如果芯片带 cache，cache 修改参考 <a class="reference internal" href="#usb-cache"><span class="std std-ref">cache 配置修改</span></a> 章节</p></li>
<li><p>调用 <cite>usbh_initialize</cite> ，填入 <cite>busid</cite> 和 USB IP 的 <cite>reg base</cite> 还有 <cite>event_handler</cite> 可缺省为NULL， <cite>busid</cite> 从 0 开始，不能超过 <cite>CONFIG_USBHOST_MAX_BUS</cite> 。基础的 cdc + hid + msc 参考 <cite>usb_host.c</cite> 文件，其余参考 <strong>platform</strong> 目录下适配</p></li>
</ul>
</section>
<section id="usbh-link-script">
<span id="id2"></span><h2>主机链接脚本修改<a class="headerlink" href="#usbh-link-script" title="Link to this heading"></a></h2>
<p>在使用主机时，如果没有修改链接脚本，会报 <cite>__usbh_class_info_start__</cite> 和 <cite>__usbh_class_info_end__</cite> 未定义的错误。因为主机协议栈需要在链接脚本中添加一个 section 来存储 class 信息。</p>
<ul class="simple">
<li><p>如果使用的是 KEIL 无需修改</p></li>
<li><p>如果使用的是 GCC ，需要在链接脚本中添加如下代码（需要放在 flash 位置，建议放最后）：</p></li>
</ul>
<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="c1">// 在 ld 文件中添加如下代码</span>
<span class="p">.</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ALIGN</span><span class="p">(</span><span class="mi">4</span><span class="p">);</span>
<span class="n">__usbh_class_info_start__</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">.;</span>
<span class="n">KEEP</span><span class="p">(</span><span class="o">*</span><span class="p">(.</span><span class="n">usbh_class_info</span><span class="p">))</span>
<span class="n">__usbh_class_info_end__</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">.;</span>
</pre></div>
</div>
<p>GCC 举例如下：</p>
<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="cm">/* The program code and other data into "FLASH" Rom type memory */</span>
<span class="p">.</span><span class="n">text</span><span class="w"> </span><span class="o">:</span>
<span class="p">{</span>
<span class="p">.</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ALIGN</span><span class="p">(</span><span class="mi">4</span><span class="p">);</span>
<span class="o">*</span><span class="p">(.</span><span class="n">text</span><span class="p">)</span><span class="w"> </span><span class="cm">/* .text sections (code) */</span>
<span class="o">*</span><span class="p">(.</span><span class="n">text</span><span class="o">*</span><span class="p">)</span><span class="w"> </span><span class="cm">/* .text* sections (code) */</span>
<span class="o">*</span><span class="p">(.</span><span class="n">glue_7</span><span class="p">)</span><span class="w"> </span><span class="cm">/* glue arm to thumb code */</span>
<span class="o">*</span><span class="p">(.</span><span class="n">glue_7t</span><span class="p">)</span><span class="w"> </span><span class="cm">/* glue thumb to arm code */</span>
<span class="o">*</span><span class="p">(.</span><span class="n">eh_frame</span><span class="p">)</span>
<span class="n">KEEP</span><span class="w"> </span><span class="p">(</span><span class="o">*</span><span class="p">(.</span><span class="n">init</span><span class="p">))</span>
<span class="n">KEEP</span><span class="w"> </span><span class="p">(</span><span class="o">*</span><span class="p">(.</span><span class="n">fini</span><span class="p">))</span>
<span class="p">.</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ALIGN</span><span class="p">(</span><span class="mi">4</span><span class="p">);</span>
<span class="n">__usbh_class_info_start__</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">.;</span>
<span class="n">KEEP</span><span class="p">(</span><span class="o">*</span><span class="p">(.</span><span class="n">usbh_class_info</span><span class="p">))</span>
<span class="n">__usbh_class_info_end__</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">.;</span>
<span class="p">.</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ALIGN</span><span class="p">(</span><span class="mi">4</span><span class="p">);</span>
<span class="n">_etext</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">.;</span><span class="w"> </span><span class="cm">/* define a global symbols at end of code */</span>
<span class="p">}</span><span class="w"> </span><span class="o">></span><span class="w"> </span><span class="n">FLASH</span>
</pre></div>
</div>
<ul class="simple">
<li><p>Segger Embedded Studio 举例如下：</p></li>
</ul>
<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">define</span><span class="w"> </span><span class="n">block</span><span class="w"> </span><span class="n">cherryusb_usbh_class_info</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">section</span><span class="w"> </span><span class="p">.</span><span class="n">usbh_class_info</span><span class="w"> </span><span class="p">};</span>
<span class="n">define</span><span class="w"> </span><span class="n">exported</span><span class="w"> </span><span class="n">symbol</span><span class="w"> </span><span class="n">__usbh_class_info_start__</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">start</span><span class="w"> </span><span class="n">of</span><span class="w"> </span><span class="n">block</span><span class="w"> </span><span class="n">cherryusb_usbh_class_info</span><span class="p">;</span>
<span class="n">define</span><span class="w"> </span><span class="n">exported</span><span class="w"> </span><span class="n">symbol</span><span class="w"> </span><span class="n">__usbh_class_info_end__</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">end</span><span class="w"> </span><span class="n">of</span><span class="w"> </span><span class="n">block</span><span class="w"> </span><span class="n">cherryusb_usbh_class_info</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span>
<span class="n">place</span><span class="w"> </span><span class="n">in</span><span class="w"> </span><span class="n">AXI_SRAM</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">block</span><span class="w"> </span><span class="n">cherryusb_usbh_class_info</span><span class="w"> </span><span class="p">};</span>
<span class="n">keep</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">section</span><span class="w"> </span><span class="p">.</span><span class="n">usbh_class_info</span><span class="p">};</span>
</pre></div>
</div>
</section>
<section id="cache">
<span id="usb-cache"></span><h2>cache 配置修改<a class="headerlink" href="#cache" title="Link to this heading"></a></h2>
<p>对于带 cache 的芯片，协议栈以及 port 中不会对 cache 区域的 ram 进行 clean 或者 invalid，所以需要使用一块非 cache 区域的 ram 来维护。
<cite>USB_NOCACHE_RAM_SECTION</cite> 宏表示将变量指定到非 cache ram上，默认 <cite>USB_NOCACHE_RAM_SECTION</cite> 定义为 <cite>__attribute__((section(“.noncacheable”)))</cite>。
因此，用户需要在对应的链接脚本中添加 no cache ram 的 section，并且 section 段包含 <cite>.noncacheable</cite>。</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>需要注意，光修改链接脚本中的 nocache section 是不够的，还需要配置该 section 中的 ram 是真的 nocache，一般需要配置 mpu 属性（arm 的参考 stm32h7 demo）。</p>
</div>
<p>GCC:</p>
<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">MEMORY</span>
<span class="p">{</span>
<span class="n">RAM</span><span class="w"> </span><span class="p">(</span><span class="n">xrw</span><span class="p">)</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">ORIGIN</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mh">0x20000000</span><span class="p">,</span><span class="w"> </span><span class="n">LENGTH</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">256</span><span class="n">K</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="mi">64</span><span class="n">K</span>
<span class="n">RAM_nocache</span><span class="w"> </span><span class="p">(</span><span class="n">xrw</span><span class="p">)</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">ORIGIN</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mh">0x20030000</span><span class="p">,</span><span class="w"> </span><span class="n">LENGTH</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">64</span><span class="n">K</span>
<span class="n">FLASH</span><span class="w"> </span><span class="p">(</span><span class="n">rx</span><span class="p">)</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">ORIGIN</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mh">0x8000000</span><span class="p">,</span><span class="w"> </span><span class="n">LENGTH</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">512</span><span class="n">K</span>
<span class="p">}</span>
<span class="p">.</span><span class="n">_nocache_ram</span><span class="w"> </span><span class="o">:</span>
<span class="p">{</span>
<span class="p">.</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ALIGN</span><span class="p">(</span><span class="mi">4</span><span class="p">);</span>
<span class="o">*</span><span class="p">(.</span><span class="n">noncacheable</span><span class="p">)</span>
<span class="p">}</span><span class="w"> </span><span class="o">></span><span class="n">RAM_nocache</span>
</pre></div>
</div>
<p>SCT:</p>
<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">LR_IROM1</span><span class="w"> </span><span class="mh">0x08000000</span><span class="w"> </span><span class="mh">0x00200000</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">;</span><span class="w"> </span><span class="n">load</span><span class="w"> </span><span class="n">region</span><span class="w"> </span><span class="n">size_region</span>
<span class="n">ER_IROM1</span><span class="w"> </span><span class="mh">0x08000000</span><span class="w"> </span><span class="mh">0x00200000</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">;</span><span class="w"> </span><span class="n">load</span><span class="w"> </span><span class="n">address</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">execution</span><span class="w"> </span><span class="n">address</span>
<span class="o">*</span><span class="p">.</span><span class="n">o</span><span class="w"> </span><span class="p">(</span><span class="n">RESET</span><span class="p">,</span><span class="w"> </span><span class="o">+</span><span class="n">First</span><span class="p">)</span>
<span class="o">*</span><span class="p">(</span><span class="n">InRoot$$Sections</span><span class="p">)</span>
<span class="p">.</span><span class="n">ANY</span><span class="w"> </span><span class="p">(</span><span class="o">+</span><span class="n">RO</span><span class="p">)</span>
<span class="p">.</span><span class="n">ANY</span><span class="w"> </span><span class="p">(</span><span class="o">+</span><span class="n">XO</span><span class="p">)</span>
<span class="p">}</span>
<span class="n">RW_IRAM2</span><span class="w"> </span><span class="mh">0x24000000</span><span class="w"> </span><span class="mh">0x00070000</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">;</span><span class="w"> </span><span class="n">RW</span><span class="w"> </span><span class="n">data</span>
<span class="p">.</span><span class="n">ANY</span><span class="w"> </span><span class="p">(</span><span class="o">+</span><span class="n">RW</span><span class="w"> </span><span class="o">+</span><span class="n">ZI</span><span class="p">)</span>
<span class="p">}</span>
<span class="n">USB_NOCACHERAM</span><span class="w"> </span><span class="mh">0x24070000</span><span class="w"> </span><span class="mh">0x00010000</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">;</span><span class="w"> </span><span class="n">RW</span><span class="w"> </span><span class="n">data</span>
<span class="o">*</span><span class="p">(.</span><span class="n">noncacheable</span><span class="p">)</span>
<span class="p">}</span>
<span class="p">}</span>
</pre></div>
</div>
<p>ICF:</p>
<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">define</span><span class="w"> </span><span class="n">region</span><span class="w"> </span><span class="n">NONCACHEABLE_RAM</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">[</span><span class="n">from</span><span class="w"> </span><span class="mh">0x1140000</span><span class="w"> </span><span class="n">size</span><span class="w"> </span><span class="mi">256</span><span class="n">K</span><span class="p">];</span>
<span class="n">place</span><span class="w"> </span><span class="n">in</span><span class="w"> </span><span class="n">NONCACHEABLE_RAM</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="n">section</span><span class="w"> </span><span class="p">.</span><span class="n">noncacheable</span><span class="p">,</span><span class="w"> </span><span class="n">section</span><span class="w"> </span><span class="p">.</span><span class="n">noncacheable</span><span class="p">.</span><span class="n">init</span><span class="p">,</span><span class="w"> </span><span class="n">section</span><span class="w"> </span><span class="p">.</span><span class="n">noncacheable</span><span class="p">.</span><span class="n">bss</span><span class="w"> </span><span class="p">};</span><span class="w"> </span><span class="c1">// Noncacheable</span>
</pre></div>
</div>
</section>
</section>
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