fix: Update README for bsp/qemu-vexpress-a9

Author: recan-li

bsp/qemu-vexpress-a9/README.md

@@ -32,9 +32,26 @@ QEMU/VExpress A9是QEMU模拟器针对ARM VExpress-A9 FPGA开发板进行软件
 
 如果在Linux下使用，请自行下载[GNU GCC工具链][3]。
 
-## 3. 执行
+## 3. 执行和退出
 
-当要执行编译好的RT-Thread时，在这个bsp目录下已经提供了运行脚本文件：qemu.bat和qemu.sh。可以在bsp目录下运行env，在env中敲入qemu.bat即可直接运行。
+### 3.1 执行脚本文件说明
+
+在这个bsp目录下已经提供了下面几个执行脚本文件，具体的说明如下表所示：
+
+| 执行脚本文件 | 运行平台  |  备注  |
+| ------ | ----  | :------:  |
+| qemu.bat | Windows | 普通模式启动运行 |
+| qemu.sh | Linux | 同上 |
+| qemu-dbg.bat | Windows | 调试模式启动运行 |
+| qemu-dbg.sh | Linux | 同上 |
+| qemu-nographic.bat | Windows | 以不带界面的模式启动运行 |
+| qemu-nographic.sh | Linux | 同上 |
+
+### 3.2 Windows下执行RT-Thread
+
+#### 3.2.1 启动QEMU运行
+
+当要执行编译好的RT-Thread时，可以在bsp目录下运行env，在env中敲入qemu.bat即可直接运行。
 
 这个执行脚本默认把串口输出到stdio（即控制台）上，所以直接执行脚本后就可以输出结果了。
 
@@ -49,6 +66,126 @@ hello rt-thread
 msh />
 ```
 
+当然你也可以尝试使用其他两个**.bat**文件启动运行。
+
+#### 3.2.2 退出QEMU运行
+
+在msh提示输入的状态下，按下 **CTRL+C** ，有以下提示之后，按下 **y** ，即可退出 QEMU 。
+
+```shell
+hello rt-thread
+msh />
+msh />
+msh />Terminate batch job (Y/N)? y
+```
+
+### 3.3 Linux下执行RT-Thread
+
+#### 3.3.1 安装QEMU工具包
+
+在Linux下调试启动与Windows下稍微有点点区别，由于Windows下安装了**env**工具就自带了**qemu-system-arm**，而Linux下默认是没有这个工具的，所以执行执行`./qemu.sh`会报错：
+
+```shell
+bsp/qemu-vexpress-a9$ ./qemu-nographic.sh
+./qemu-nographic.sh: line 5: /usr/bin/qemu-system-arm: No such file or directory
+```
+
+这个时候需要在Linux平台安装**qemu-system-arm**工具包，以**Linux Ubuntu**平台为例，使用以下命令即可安装对应的工具包：
+
+```shell
+bsp/qemu-vexpress-a9$ sudo apt-get install qemu-system-arm
+Reading package lists... Done
+Building dependency tree       
+Reading state information... Done
+The following package was automatically installed and is no longer required:
+  tinyproxy-bin
+Use 'sudo apt autoremove' to remove it.
+Suggested packages:
+  vde2
+The following NEW packages will be installed:
+  qemu-system-arm
+0 upgraded, 1 newly installed, 0 to remove and 168 not upgraded.
+Need to get 0 B/7,722 kB of archives.
+After this operation, 36.6 MB of additional disk space will be used.
+Selecting previously unselected package qemu-system-arm.
+(Reading database ... 159586 files and directories currently installed.)
+Preparing to unpack .../qemu-system-arm_1%3a4.2-3ubuntu6.17_amd64.deb ...
+Unpacking qemu-system-arm (1:4.2-3ubuntu6.17) ...
+Setting up qemu-system-arm (1:4.2-3ubuntu6.17) ...
+Processing triggers for man-db (2.9.1-1) ...
+```
+
+提示安装成功后，输入查看**qemu-system-arm**版本信息的命令，如果可以看到对应的版本信息，证明它可以正常使用。
+
+```shell
+/bsp/qemu-vexpress-a9$ qemu-system-arm --version
+QEMU emulator version 4.2.1 (Debian 1:4.2-3ubuntu6.17)
+Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers
+```
+
+#### 3.3.2 启动QEMU运行
+
+由于Linux平台一般都是不带界面的服务器，所以推荐使用`qemu-nographic.sh`脚本来启动运行，参考运行示例如下：
+
+```shell
+bsp/qemu-vexpress-a9$ ./qemu-nographic.sh
+WARNING: Image format was not specified for 'sd.bin' and probing guessed raw.
+         Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
+         Specify the 'raw' format explicitly to remove the restrictions.
+ALSA lib confmisc.c:767:(parse_card) cannot find card '0'
+ALSA lib conf.c:4732:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory
+ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
+ALSA lib conf.c:4732:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory
+ALSA lib confmisc.c:1246:(snd_func_refer) error evaluating name
+ALSA lib conf.c:4732:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
+ALSA lib conf.c:5220:(snd_config_expand) Evaluate error: No such file or directory
+ALSA lib pcm.c:2642:(snd_pcm_open_noupdate) Unknown PCM default
+alsa: Could not initialize DAC
+alsa: Failed to open `default':
+alsa: Reason: No such file or directory
+ALSA lib confmisc.c:767:(parse_card) cannot find card '0'
+ALSA lib conf.c:4732:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory
+ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
+ALSA lib conf.c:4732:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory
+ALSA lib confmisc.c:1246:(snd_func_refer) error evaluating name
+ALSA lib conf.c:4732:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
+ALSA lib conf.c:5220:(snd_config_expand) Evaluate error: No such file or directory
+ALSA lib pcm.c:2642:(snd_pcm_open_noupdate) Unknown PCM default
+alsa: Could not initialize DAC
+alsa: Failed to open `default':
+alsa: Reason: No such file or directory
+audio: Failed to create voice `lm4549.out'
+
+ \ | /
+- RT -     Thread Operating System
+ / | \     4.1.0 build Nov 24 2021 19:49:17
+ 2006 - 2021 Copyright by rt-thread team
+lwIP-2.1.2 initialized!
+[I/sal.skt] Socket Abstraction Layer initialize success.
+[I/SDIO] SD card capacity 65536 KB.
+[I/SDIO] switching card to high speed failed!
+[W/POSIX.delay] Please consider implementing rt_hw_us_delay() in another file.
+[W/POSIX.delay] Please consider implementing rt_hw_us_delay() in another file.
+[W/POSIX.delay] Please consider implementing rt_hw_us_delay() in another file.
+hello rt-thread
+msh />
+msh />
+msh />
+```
+
+**注意**： 前面的错误信息可以忽略，能看到RT-Thread的启动logo输出，以及msh能正常输入输出，即可进行代码调试了。
+
+#### 3.3.3 退出QEMU运行
+
+Linux下退出QEMU的方式与Windows下有些不一样；在msh提示输入的状态下，按下 **CTRL+A** ，再按下 **X** ，即可退出 QEMU 。
+
+```shell
+hello rt-thread
+msh />
+msh />
+msh />QEMU: Terminated
+```
+
 ## 4. 支持情况
 
 | 驱动 | 支持情况  |  备注  |
@@ -97,9 +234,11 @@ start qemu-system-arm -M vexpress-a9 -kernel rtthread.elf -serial stdio -sd sd.b
 
 ## 5. 联系人信息
 
-维护人：[bernard][4]
+维护人：[bernard][4]  [recan-li][5]
 
 [1]: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.subset.boards.express/index.html
 [2]: https://www.rt-thread.org/page/download.html
 [3]: https://launchpad.net/gcc-arm-embedded/5.0/5-2016-q3-update/+download/gcc-arm-none-eabi-5_4-2016q3-20160926-linux.tar.bz2
-[4]: https://github.com/BernardXiong
+[4]: https://github.com/BernardXiong
+[5]: https://github.com/recan-li
+