更新u-boot: Kconfig, 配置

09_u-boot完全分析与移植/doc_pic/03_配置u-boot的过程分析.md

@@ -166,9 +166,9 @@ conf_write(NULL); // 写到.config
   * ARM架构
   * 自己的一些配置项
 * 怎么处理呢？
-  * defconfig_file：直接写入.config
-  * 使用defconfig_file的内容去解析Kconfig，把各个依赖的配置项也写入.config
+  * 使用defconfig_file的内容去解析Kconfig，确定各个依赖的配置项
   * 其他未涉及的配置项，给它们指定默认值
+  * 写入.config
 
 
 

09_u-boot完全分析与移植/doc_pic/04_Kconfig介绍.md

@@ -0,0 +1,555 @@
+## Kconfig介绍
+
+参考文档：
+
+```
+任一个Linux内核的Documentation\kbuild\kconfig-language.rst
+
+https://www.rt-thread.org/document/site/programming-manual/kconfig/kconfig/
+```
+
+对于各类内核，只要支持menuconfig配置界面，都是使用Kconfig。
+在配置界面中，可以选择、设置选项，这些设置会保存在.config文件里。
+编译脚本会包含.config，根据里面的值决定编译哪些文件、怎么编译文件。
+.config文件也会被转换为头文件，C程序可以从头文件中获得配置信息。
+
+### 1.1 配置界面示例
+
+![image-20230319092829529](pic/03_Kconfig和Makefile/001_Kconfig_menuconfig.png)
+
+问题：
+
+* 这个界面里，各个配置项来自哪里
+* 这个界面里，这些配置项是怎么组织的
+* 这个界面里，我们的选择、设置，结果保存在哪里
+* 这些配置结果，怎么使用
+
+### 1.2 配置结果的保存
+
+#### 1.2.1 示例
+
+在配置界面中操作的结果保存在.config文件中，示例如下：
+
+```
+#
+# Automatically generated file; DO NOT EDIT.
+# U-Boot  Configuration
+#
+CONFIG_CREATE_ARCH_SYMLINK=y
+# CONFIG_ARC is not set
+CONFIG_ARM=y
+# CONFIG_AVR32 is not set
+# CONFIG_BLACKFIN is not set
+# CONFIG_M68K is not set
+# CONFIG_MICROBLAZE is not set
+# CONFIG_MIPS is not set
+# CONFIG_NDS32 is not set
+# CONFIG_NIOS2 is not set
+# CONFIG_OPENRISC is not set
+# CONFIG_PPC is not set
+# CONFIG_SANDBOX is not set
+# CONFIG_SH is not set
+# CONFIG_SPARC is not set
+# CONFIG_X86 is not set
+# CONFIG_XTENSA is not set
+CONFIG_SYS_ARCH="arm"
+CONFIG_SYS_CPU="armv7"
+CONFIG_SYS_SOC="mx6"
+CONFIG_SYS_VENDOR="freescale"
+CONFIG_SYS_BOARD="mx6ullevk"
+CONFIG_SYS_CONFIG_NAME="mx6ullevk"
+
+#
+# ARM architecture
+#
+CONFIG_HAS_VBAR=y
+CONFIG_HAS_THUMB2=y
+CONFIG_CPU_V7=y
+CONFIG_SYS_ARM_ARCH=7
+CONFIG_SYS_CACHE_SHIFT_6=y
+CONFIG_SYS_CACHELINE_SIZE=64
+```
+
+编译脚本会包含.config文件，它会根据里面的变量比如`CONFIG_CPU_V7`选择u-boot特性。
+
+#### 1.2.2 配置项的前缀
+
+在Kconfig文件中，假设配置项的名字是XXX，在.config文件中：
+
+* 默认情况下，它对应的变量名为`CONFIG_XXX`
+* 如果设置了环境变量`CONFIG_=ABC`，则对应的变量名为`ABC_XXX`
+
+  
+
+### 1.3 描述单个配置项config
+
+#### 1.3.1 示例
+
+在`menuconfig`界面，可以看到这个配置项：
+
+![image-20230319093006596](pic/03_Kconfig和Makefile/002_Kconfig_item_example.png)
+
+在配置界面，使用方向箭头游走到`Display information about the CPU during start up`后，可以：
+
+* 输入Y，选择配置项，在.config中对应`CONFIG_DISPLAY_CPUINFO=y`
+
+* 输入N，不选择配置项，在.config中对应`# CONFIG_DISPLAY_CPUINFO is not set`
+
+  
+
+上图中的配置项怎么实现的？
+在common/Kconfig文件中，它对应下列代码：
+
+![image-20230319093438365](pic/03_Kconfig和Makefile/003_config_item_example.png)
+
+
+#### 1.3.2 语法
+上面是一个精简的例子，完整的例子可以从Linux中获得，如下：
+
+```shell
+config SGI_SNSC
+        bool "SGI Altix system controller communication support"
+        depends on (IA64_SGI_SN2 || IA64_GENERIC)
+        default y
+        help
+          If you have an SGI Altix and you want to enable system
+          controller communication from user space (you want this!),
+          say Y.  Otherwise, say N.
+```
+解释如下：
+
+* config
+  表示`config option`，这是Kconfig的基本entry；其他entry是用来管理config的。
+  config 表示一个配置选项的开始，紧跟着的 SGI_SNSC 是配置选项的名称。
+  config 下面几行定义了该配置选项的属性。
+  属性可以是该配置选项的：类型、输入提示、依赖关系、默认值、帮助信息。
+  - bool 表示配置选项的类型，每个 config 菜单项都要有类型定义，变量有5种类型
+    - bool 布尔类型
+    - tristate 三态类型
+    - string 字符串
+    - hex 十六进制
+    - int 整型
+  - "SGI Altix system controller communication support"：提示信息
+  - depends on：表示依赖关系，只有(IA64_SGI_SN2 || IA64_GENERIC)被选中，才可以选择SGI_SNSC
+  - select XXX：表示反向依赖关系，即当前配置选项被选中后，`XXX`选项就会被选中。
+  - default 表示配置选项的默认值，bool 类型的默认值可以是 y/n。
+  - help 帮助信息，在`menuconfig`界面输入H键时，就会提示帮助信息。
+
+### 1.4 实现菜单menu/endmenu
+
+#### 1.4.1 示例
+
+示例代码：`rt-smart/kernel/src/Kconfig`，代码如下：
+
+```shell
+menu "Boot media"
+
+config NOR_BOOT
+        bool "Support for booting from NOR flash"
+        depends on NOR
+        help
+          Enabling this will make a U-Boot binary that is capable of being
+          booted via NOR.  In this case we will enable certain pinmux early
+          as the ROM only partially sets up pinmux.  We also default to using
+          NOR for environment.
+
+config NAND_BOOT
+        bool "Support for booting from NAND flash"
+        default n
+        help
+          Enabling this will make a U-Boot binary that is capable of being
+          booted via NAND flash. This is not a must, some SoCs need this,
+          some not.
+
+config ONENAND_BOOT
+        bool "Support for booting from ONENAND"
+        default n
+        help
+          Enabling this will make a U-Boot binary that is capable of being
+          booted via ONENAND. This is not a must, some SoCs need this,
+          some not.
+
+config QSPI_BOOT
+        bool "Support for booting from QSPI flash"
+        default n
+        help
+          Enabling this will make a U-Boot binary that is capable of being
+          booted via QSPI flash. This is not a must, some SoCs need this,
+          some not.
+
+config SATA_BOOT
+        bool "Support for booting from SATA"
+        default n
+        help
+          Enabling this will make a U-Boot binary that is capable of being
+          booted via SATA. This is not a must, some SoCs need this,
+          some not.
+
+config SD_BOOT
+        bool "Support for booting from SD/EMMC"
+        default n
+        help
+          Enabling this will make a U-Boot binary that is capable of being
+          booted via SD/EMMC. This is not a must, some SoCs need this,
+          some not.
+
+config SPI_BOOT
+        bool "Support for booting from SPI flash"
+        default n
+        help
+          Enabling this will make a U-Boot binary that is capable of being
+          booted via SPI flash. This is not a must, some SoCs need this,
+          some not.
+
+endmenu
+
+```
+
+界面如下：
+
+![image-20230319093820556](pic/03_Kconfig和Makefile/004_menuconfig_menu_example.png)
+
+#### 1.4.2 语法
+
+解释如下：
+
+* menu "xxx"表示一个菜单，菜单名是"xxx"
+
+* menu和endmenu之间的entry都是"xxx"菜单的选项
+
+* 在上面的例子中子菜单有6个选项：
+
+  ![image-20230319093946787](pic/03_Kconfig和Makefile/015_menu_items.png)
+
+  
+
+
+### 1.5 实现单选choice/endchoice
+
+#### 1.5.1 示例
+
+示例代码：`rt-smart/kernel/src/Kconfig`，代码如下：
+
+```shell
+config DEBUG_UART
+        bool "Enable an early debug UART for debugging"
+        help
+          The debug UART is intended for use very early in U-Boot to debug
+          problems when an ICE or other debug mechanism is not available.
+
+choice
+        prompt "Select which UART will provide the debug UART"
+        depends on DEBUG_UART
+        default DEBUG_UART_NS16550
+
+config DEBUG_UART_ALTERA_JTAGUART
+        bool "Altera JTAG UART"
+        help
+          Select this to enable a debug UART using the altera_jtag_uart driver.
+          You will need to provide parameters to make this work. The driver will
+          be available until the real driver model serial is running.
+
+config DEBUG_UART_ALTERA_UART
+        bool "Altera UART"
+        help
+          Select this to enable a debug UART using the altera_uart driver.
+          You will need to provide parameters to make this work. The driver will
+          be available until the real driver model serial is running.
+
+endchoice
+```
+
+界面如下：
+
+![image-20230319094841692](pic/03_Kconfig和Makefile/005_menuconfig_choice_example.png)
+
+
+
+在上述界面中，设置了`DEBUG_UART`，才有后续的"选择菜单"。
+
+
+
+#### 1.5.2 语法
+
+解释如下：
+
+* choice表示"选择"
+* choice和endchoice之间的entry是可以选择的项目
+  * 它们之间，只能有一个被设置为"y"：表示编进内核
+  * 它们之间，可以设置多个为"m"：表示编译为模块
+  * 比如一个硬件有多个驱动程序
+    * 同一时间只能有一个驱动能编进内核
+    * 但是多个驱动都可以单独编译为模块
+
+
+
+### 1.6 menuconfig
+
+`menuconfig XXX`和`config XXX`类似，
+唯一不同的是该选项除了能设置y/m/n外，还可以实现菜单效果(**能回车进入该项内部**)。
+
+#### 1.6.1 示例
+
+示例代码：`Kconfig`
+
+```shell
+menuconfig EXPERT
+        bool "Configure standard U-Boot features (expert users)"
+        default y
+        help
+          This option allows certain base U-Boot options and settings
+          to be disabled or tweaked. This is for specialized
+          environments which can tolerate a "non-standard" U-Boot.
+          Use this only if you really know what you are doing.
+
+if EXPERT
+        config SYS_MALLOC_CLEAR_ON_INIT
+        bool "Init with zeros the memory reserved for malloc (slow)"
+        default y
+        help
+          This setting is enabled by default. The reserved malloc
+          memory is initialized with zeros, so first malloc calls
+          will return the pointer to the zeroed memory. But this
+          slows the boot time.
+
+          It is recommended to disable it, when CONFIG_SYS_MALLOC_LEN
+          value, has more than few MiB, e.g. when uses bzip2 or bmp logo.
+          Then the boot time can be significantly reduced.
+          Warning:
+          When disabling this, please check if malloc calls, maybe
+          should be replaced by calloc - if one expects zeroed memory.
+
+config TOOLS_DEBUG
+        bool "Enable debug information for tools"
+        help
+          Enable generation of debug information for tools such as mkimage.
+          This can be used for debugging purposes. With debug information
+          it is possible to set breakpoints on particular lines, single-step
+          debug through the source code, etc.
+
+endif # EXPERT
+
+```
+
+界面如下：
+
+![image-20230321115421274](pic/03_Kconfig和Makefile/006_menuconfig_menuconfig_example.png)
+
+
+
+#### 1.6.2 语法
+
+menuconfig常用格式有2种：
+
+```shell
+  menuconfig M
+  if M
+      config C1
+      config C2
+  endif
+```
+
+或：
+
+```shell
+  menuconfig M
+  config C1
+      depends on M
+  config C2
+      depends on M
+```
+
+第1项`menuconfig M`跟`config M`语法是一样的，
+不同之处在于`menuocnfig M`后面可以跟着好几个依赖于M的`config C1`、`config C2`等子配置项。
+
+### 1.7 if/endif
+
+#### 1.7.1 语法
+
+在上面的menuconfig中就有`if/endif`的使用，它的语法如下：
+
+```shell
+"if" <expr>
+<if block>
+"endif"
+```
+
+#### 1.7.2 示例
+
+示例如下，只有定义了的EXPERT项，`SYS_MALLOC_CLEAR_ON_INIT`等才会显示出来：
+
+```shell
+if EXPERT
+        config SYS_MALLOC_CLEAR_ON_INIT
+        bool "Init with zeros the memory reserved for malloc (slow)"
+        default y
+        help
+          This setting is enabled by default. The reserved malloc
+          memory is initialized with zeros, so first malloc calls
+          will return the pointer to the zeroed memory. But this
+          slows the boot time.
+
+          It is recommended to disable it, when CONFIG_SYS_MALLOC_LEN
+          value, has more than few MiB, e.g. when uses bzip2 or bmp logo.
+          Then the boot time can be significantly reduced.
+          Warning:
+          When disabling this, please check if malloc calls, maybe
+          should be replaced by calloc - if one expects zeroed memory.
+
+config TOOLS_DEBUG
+        bool "Enable debug information for tools"
+        help
+          Enable generation of debug information for tools such as mkimage.
+          This can be used for debugging purposes. With debug information
+          it is possible to set breakpoints on particular lines, single-step
+          debug through the source code, etc.
+
+endif # EXPERT
+```
+
+### 1.8 source
+
+source 语句用于读取另一个文件中的 Kconfig 文件，
+比如`Kconfig`中就包含了其他Kconfig：
+
+```shell
+source "arch/Kconfig"
+```
+
+### 1.9 comment 
+
+comment 语句出现在界面的第一行，用于定义一些提示信息，如`cmd/Kconfig`：
+
+```shell
+comment "Commands"
+```
+
+界面如下：
+![image-20230321115907412](pic/03_Kconfig和Makefile/007_menuconfig_comment_example.png)
+
+### 1.10 测试代码
+
+#### 1.10.1 config
+
+```shell
+config 100ASK
+        bool "test for 100ask"
+        default y
+        help
+          just for Kconfig test
+```
+
+
+
+#### 1.10.2 menu(多选)
+
+```shell
+menu "100ASK menu"
+
+config IMX6ULL_TEST
+        tristate "menu test item 1 IMX6ULL"
+        help
+          just for test menu.
+
+config STM32MP157_TEST
+        tristate "menu test item 2 IMX6ULLh"
+        help
+          just for test menu.
+endmenu
+```
+
+
+
+#### 1.10.3 choice(单选)
+
+```shell
+config CHOICE_ON_100ASK
+        bool "Enable choice for 100ask"
+        help
+          Enable choice for 100ask
+
+choice
+        prompt "choice test for 100ask"
+        depends on CHOICE_ON_100ASK
+
+config CHOICE_ITEM1
+        bool "CHOICE_ITEM1"
+        help
+          CHOICE_ITEM1.
+
+config CHOICE_ITEM2
+        bool "CHOICE_ITEM2"
+        help
+          CHOICE_ITEM2.
+
+endchoice
+```
+
+
+
+#### 1.10.4 menuconfig
+
+```shell
+menuconfig 100ASK_MENUCFG
+         bool "test for menuconfig of 100ask"
+
+if 100ASK_MENUCFG
+config IMX6ULL_TEST_MENUCFG
+        tristate "menuconfig test item 1 IMX6ULL"
+        help
+          just for test menuconfig.
+
+config STM32MP157_MENUCFG
+        tristate "menuconfig test item 2 IMX6ULLh"
+        help
+          just for test menuconfig.
+endif
+```
+
+
+
+
+
+```shell
+menu "test menu"
+config TEST_A
+    bool "TEST A"
+    default y
+    
+config TEST_B
+    bool "TEST B"
+    default y
+
+endmenu
+
+choice
+        prompt "test choise"
+        default TEST_C
+
+config TEST_C
+    bool "TEST C"
+    default y
+    
+config TEST_D
+    bool "TEST D"
+    default y
+
+endchoice        
+
+menuconfig TEST_MENUCONFIG
+    bool "test menuconfig"
+    default n
+    
+if TEST_MENUCONFIG
+config TEST_E
+    bool "TEST E"
+    default y
+
+config TEST_F
+    bool "TEST F"
+    default y
+
+
+endif
+```
+

09_u-boot完全分析与移植/doc_pic/05_编译uboot的过程分析.md

@@ -0,0 +1,30 @@
+# 5. 编译uboot的过程分析
+
+
+
+## 5.1 体验
+
+```shell
+IMX6ULL: 
+make mx6ull_14x14_evk_defconfig
+make
+
+STM32MP157: 
+make stm32mp15_trusted_defconfig
+make
+```
+
+
+
+make过程
+
+* 检查、更新头文件，比如include/config.h 、u-boot.cfg
+* 制作工具
+* 交叉编译
+  * 编译哪些目录、哪些文件？
+  * .c文件可能需要使用.config的配置值，它可以引用config.h
+
+
+
+## 5.2 详细分析
+