uboot 完整源码追踪注释

robe.zhang · 发表于 2018-8-15 09:04:13

uboot 完整的源码追踪注释，代码比较多，细节会有错误，程序走向没有问题，
从第一行代码：b reset
到最后一行：kernel_entry(0, machid, r2);
完整源码追踪做了注释
本文格式：缩进代表是上层函数的子函数，像 python 那样。括号中是文件全路径。
u-boot.lds(arch/arm/lib/vectors.S) .globl _start b reset ldr pc, _undefined_instruction ldr pc, _software_interrupt ldr pc, _prefetch_abort ldr pc, _data_abort ldr pc, _not_used ldr pc, _irq ldr pc, _fiq .globl _undefined_instruction .globl _software_interrupt .globl _prefetch_abort .globl _data_abort .globl _not_used .globl _irq .globl _fiq _undefined_instruction: .word undefined_instruction _software_interrupt: .word software_interrupt _prefetch_abort: .word prefetch_abort _data_abort: .word data_abort _not_used: .word not_used _irq: .word irq _fiq: .word fiq .globl IRQ_STACK_START_IN IRQ_STACK_START_IN: .globl IRQ_STACK_START IRQ_STACK_START: .globl FIQ_STACK_START FIQ_STACK_START: 中断处理函数：寄存器压栈，处理结束，弹栈 do_undefined_instruction do_software_interrupt do_prefetch_abort do_data_abort do_not_used do_irq do_fiq (arch/arm/lib/interrupts.c) (arch/arm/cpu/armv7/start.S) .reset .save_boot_params_ret reset: save_boot_params_ret: 关闭FIQ/IRQ, 设置SVC32，或者进HYP模式设置向量表_start(定义CONFIG_SPL_BUILD) cpu_init_cp15: 关mmu，关caches，开i-cache cpu_init_crit: lowlevel_init：设置sp指针=CONFIG_SYS_INIT_SP_ADDR，清零r9,=0(定义CONFIG_SPL_DM) 设置r9,=gdata(定义CONFIG_SPL_BUILD) 设置r9,放到 sp 空间上面 s_init: 设置PLL _main：(arch/arm/lib/crt0.S

_main ldr sp, =(CONFIG_SYS_INIT_SP_ADDR): 设置sp #define CONFIG_SYS_INIT_SP_ADDR (CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_INIT_SP_OFFSET) #define CONFIG_SYS_INIT_RAM_ADDR IRAM_BASE_ADDR #define IRAM_BASE_ADDR 0x00900000 #define CONFIG_SYS_INIT_SP_OFFSET (CONFIG_SYS_INIT_RAM_SIZE - GENERATED_GBL_DATA_SIZE) #define CONFIG_SYS_INIT_RAM_SIZE IRAM_SIZE #define IRAM_SIZE 0x00020000 board_init_f_alloc_reserve： (common/init/board_init.c

：保留1k空间设置r9 board_init_f_init_reserve： (common/init/board_init.c

：设置gd->malloc_base board_init_f： (common/board_f.c

: 清零gd空间，设置gd->flags=0,gd->have_console=0 initcall_run_list: init_sequence_f

common/board_f.c)init_sequence_f: setup_mon_len: 设置gd->mon_len = (ulong)&__bss_end - (ulong)_start; initf_malloc：设置gd->malloc_ptr = 0;设置gd->malloc_limit = CONFIG_SYS_MALLOC_F_LEN; initf_console_record：空 arch_cpu_init： (arch/arm/cpu/armv7/mx6) init_aips: clear_mmdc_ch_mask: init_src: initf_dm： dm_init_and_scan: dm_init: gd->dm_root存在，返回。不存在初始化gd->uclass_root device_bind_by_name： device_probe： dm_scan_platdata： dm_scan_other： arch_cpu_init_dm：空 mark_bootstage: 添加record记录(static struct bootstage_record record[BOOTSTAGE_ID_COUNT] = { {1} };) board_early_init_f: (board/myir/mys_imx6ull/mys_imx6ull.c) //修改1 setup_iomux_uart: 设置串口 timer_init： (arch/arm/imx-common/syscounter.c) 初始化启动syscounter，清零gd->arch.tbl，gd->arch.tbu board_postclk_init： set_ldo_voltage： get_clocks：设置gd->arch.sdhc_clk env_init：设置gd->env_addr=default_environment[]地址，(include/env_default.h) 设置gd->env_valid=1 init_baud_rate: 设置gd->baudrate serial_init：设置gd->flags |= GD_FLG_SERIAL_READY; get_current: default_serial_console： mxc_serial_drv： struct serial_device mxc_serial_drv={ .name = "mxc_serial", .start = mxc_serial_init, .stop = NULL, .setbrg = mxc_serial_setbrg, .putc = mxc_serial_putc, .puts = default_serial_puts, .getc = mxc_serial_getc, .tstc = mxc_serial_tstc, } get_current()->start(): 初始化串口，并使能。(drivers/serial/serial_mxc.c) console_init_f: 设置gd->have_console=1,初始化console display_options： [打印]u-boot第一次开始输出信息，输出版本信息 display_text_info: print_cpuinfo： [打印]cpu信息，reset cause：por 信息 show_board_info： [打印]board信息，(board/myir/mys_imx6ull/mys_imx6ull.c) announce_dram_init： puts打印信息 dram_init： get_ram_size：获取实际ram size，赋值给gd->ram_size setup_dest_addr: 重新设置内存分配内存设置gd->relocaddr = gd->ram_top reserve_round_4k：设置gd->relocaddr 4k对齐 reserve_mmu：设置gd->arch.tlb_size，gd->arch.tlb_addr reserve_trace：空 reserve_uboot：预留gd->mon_len reserve_malloc：预留TOTAL_MALLOC_LEN reserve_board：预留gd->bd，设置gd->bd setup_machine：设置gd->bd->bi_arch_number reserve_global_data：预留gd->new_gd空间，设置gd->new_gd reserve_fdt：预留gd->new_fdt，设置gd->new_fdt arch_reserve_stacks：预留gd->irq_sp，设置gd->irq_sp dram_init_banksize：设置gd->bd->bi_dram[0].start，设置gd->bd->bi_dram[0].size show_dram_config： [打印]dram信息 display_new_sp: [打印]gd->start_addr_sp信息(已设置gd->start_addr_sp) setup_board_extra：设置gd->bd->bi_s_version，设置gd->bd->bi_r_version，设置gd->bd->bi_procfreq = gd->cpu_clk 设置gd->bd->bi_plb_busfreq = gd->bus_clk reloc_fdt：复制memcpy(gd->new_fdt, gd->fdt_blob, gd->fdt_size); 设置gd->fdt_blob = gd->new_fdt; setup_reloc：复制memcpy(gd->new_gd, (char *)gd, sizeof(gd_t)); 未完接下页
(arch/arm/lib/crt0.S

_main sp = gd->start_addr_sp r9 = new GD 设置返回寄存器 r0 = gd->relocaddr b relocate_code(arch/arm/lib/relocate.S

relocate_code 复制 __image_copy_start 和 __image_copy_end 之间代码(arch/arm/lib/crt0.S

_main bl relocate_vectors(arch/arm/lib/relocate.S

relocate_vectors r0 = gd->relocaddr 复制代码(arch/arm/lib/crt0.S

_main bl c_runtime_cpu_setup：关闭I-cache 清空bss bl coloured_LED_init bl red_led_on mov r0, r9 /* gd_t */ ldr r1, [r9, #GD_RELOCADDR] /* dest_addr */ ldr pc, =board_init_r(common/baord_r.c

board_init_r initcall_run_list: init_sequence_rinit_sequence_r: initr_reloc: 设置gd->flags gd->flags |= GD_FLG_RELOC | GD_FLG_FULL_MALLOC_INIT; initr_caches: 使能D-cache initr_reloc_global_data: 设置monitor_flash_len monitor_flash_len = _end - __image_copy_start; initr_barrier：空 initr_malloc：设置malloc_start，并初始化 malloc_start = gd->relocaddr - TOTAL_MALLOC_LEN; initr_console_record：空 bootstage_relocate：复制record initr_dm： gd->dm_root_f = gd->dm_root; gd->dm_root = NULL; dm_init： device_bind_by_name：初始化gd->dm_root，(udevice) initr_bootstage：空 board_init： //修改2 gd->bd->bi_boot_params = PHYS_SDRAM + 0x100; 设置变量 imx_iomux_v3_setup_multiple_pads 初始化pads(gpio5:7/8/10/11) SNVS_TAMPER7/8 和 bootmode iox74lv_init 检查boot mode setup_i2c 设置pad，设置复用，使能clk setup_fec setup_usb board_qspi_init setup_gpmi_nand stdio_init_tables: 初始化struct stdio_dev的list变量 initr_serial, serial_initialize 初始化所有串口 initr_announce, 打印信息 power_init_board：空 initr_nand 空 initr_onenand 空 initr_mmc mmc_initialize INIT_LIST_HEAD (&mmc_devices); 初始化mmc_devices mmc_probe probe do_preinit 初始化mmc卡 initr_dataflash 空 initr_env env_relocate 设置env，从emmc分配空间 load_addr = getenv_ulong("loadaddr", 16, load_addr); 设置load_addr initr_malloc_bootparams 空 initr_secondary_cpu 空 mac_read_from_eeprom 空 stdio_add_devices, drv_video_init board_video_skip 找到displays，配置lcdif pad. video_init mxs_lcd_init 设置lcdc stdio_register(&console_dev) 注册console_dev设备 drv_system_init 注册"serial"设备 serial_stdio_init 注册serial_device设备 drv_jtag_console_init 注册"jtag"设备 initr_jumptable, 给gd->jt分配堆空间 console_init_r console_setfile 设置stdio_devices[file] = dev;初始化gd->jf->getc/putc setenv(stdio_names, stdio_devices->name) 设置stdio_devices名字 interrupt_init 中断初始化,设置堆栈指针 (中断处理实现在arch/arm/lib/interrupts.c) IRQ_STACK_START = gd->irq_sp - 4; IRQ_STACK_START_IN = gd->irq_sp + 8; FIQ_STACK_START = IRQ_STACK_START - CONFIG_STACKSIZE_IRQ; initr_enable_interrupts 开中断 initr_ethaddr 获取环境变量ip地址，验证有效性 board_late_init 增加sd/qspi启动模式，//修改3 setenv("board_name", "MYS6ULL"); 设置环境变量 setenv("board_rev", "14X14"); board_late_mmc_env_init 检测mmc是否启动设备 mmc_get_env_dev 获取mmc启动设备 getenv("mmcautodetect"); 获取mmcautodetect环境变量，并判断是否等于yes，决定是否mmc启动 strcmp(autodetect_str, "yes") 设置环境变量mmcdev/mmcroot run_command(cmd, 0); 执行cmd启动 sprintf(cmd, "mmc dev %d", dev_no); set_wdog_reset 使能看门狗 initr_net 初始化，或者reset eth控制器 initr_check_fastboot 是否需要从 fastboot 启动 run_main_loop 主循环 main_loop 陷入死循环执行 main_loop 中(common/main.c:)main_loop cli_init cli环境初始化 run_preboot_environment_command 获取preboot 环境变量，并执行 s = bootdelay_process(); bootdelay_process s = getenv("bootdelay"); 获取bootdelay环境变量，保存到stored_bootdelsy stored_bootdelsy = s retrun s;s = getenv("bootcmd"); 返回bootcmd指令 if (cli_process_fdt(&s)) 查找设备树是否有bootcmd，有的话覆盖环境变量bootcmd，并执行bootcmd，然后hang cli_secure_boot_cmd(s); (如果fdt设置了secureboot,就从fdt，bootcmd启动。) autoboot_command(s); 如果在bootdelay时间内按了按键，不执行bootcmd，不然直接启动 run_command_list(s, -1, 0); 启动前后关闭恢复disable_ctrlc 功能 cli_loop();(common/cli.c:)run_command_list(s, -1, 0) parse_string_outer(buff, FLAG_PARSE_SEMICOLON); =parse_string_outer("bootcmd", (1<<1));(common/cli_hush.c:)parse_string_outer parse_stream_outer run_list run_list_real run_pipe_real cmd_process cmd_call (cmdtp->cmd)(cmdtp, flag, argc, argv);(cmd/bootm.c)do_bootz bootz_start do_bootm_states bootm_start bootm_find_os bootm_find_other bootm_disable_interrupts bootm_load_os lmb_reserve bootm_os_get_boot_func boot_selected_os arch_preboot_os boot_fn do_bootm_linux boot_prep_linux boot_jump_linux kernel_entry(0, machid, r2);源码到 kernel_entery 结束了，下一页看几个相关的东西

几个结构，结构体，宏，环境变量等：kernel_entry, cmd_tbl_s，U_BOOT_CMD，env 。
/* kernel_entry */void (*kernel_entry)(int zero, int arch, uint params);/* cmd_tbl_s / cmd_tbl_t 结构体 */struct cmd_tbl_s { char *name; /* Command Name */ int maxargs; /* maximum number of arguments */ int repeatable; /* autorepeat allowed? */ /* Implementation function */ int (*cmd)(struct cmd_tbl_s *, int, int, char * const []); char *usage; /* Usage message (short) */#ifdef CONFIG_SYS_LONGHELP char *help; /* Help message (long) */#endif#ifdef CONFIG_AUTO_COMPLETE /* do auto completion on the arguments */ int (*complete)(int argc, char * const argv[], char last_char, int maxv, char *cmdv[]);#endif};/* U_BOOT_CMD 宏定义解析 */U_BOOT_CMD(_name, _maxargs, _rep, _cmd, _usage, _help)U_BOOT_CMD_COMPLETE(_name, _maxargs, _rep, _cmd, _usage, _help, NULL)ll_entry_declare(cmd_tbl_t, _name, cmd) = U_BOOT_CMD_MKENT_COMPLETE(_name, _maxargs, _rep, _cmd,_usage, _help, _comp);ll_entry_declare(cmd_tbl_t, _name, cmd) = { #_name, _maxargs, _rep, _cmd, _usage,_CMD_HELP(_help) _CMD_COMPLETE(_comp) }//U_BOOT_CMD 宏解析结果，两种情况ll_entry_declare(cmd_tbl_t, _name, cmd) = { #_name, _maxargs, _rep, _cmd, _usage,_help _comp}ll_entry_declare(cmd_tbl_t, _name, cmd) = { #_name, _maxargs, _rep, _cmd, _usage, }/* env */ baudrate=115200board_name=MYS6ULLboard_rev=14X14boot_fdt=trybootargs=console=ttymxc0,115200 root=/dev/nfs ip=dhcp nfsroot=:,v3,tcpbootcmd=run findfdt;mmc dev ${mmcdev};mmc dev ${mmcdev}; if mmc rescan; then if run loadbootscript; then run bootscript; else if run loadimage; then run mmcboot; else run netboot; fi; fi; else run netboot; fibootcmd_mfg=run mfgtool_args;bootz ${loadaddr} ${initrd_addr} ${fdt_addr};bootdelay=3bootscript=echo Running bootscript from mmc ...; sourceconsole=ttymxc0ethact=FEC0ethprime=FECfdt_addr=0x83000000fdt_file=mys-imx6ull-14x14.dtbfdt_high=0xfffffffffindfdt=if test $fdt_file = undefined; then if test $board_name = EVK && test $board_rev = 9X9; then setenv fdt_file imx6ull-9x9-evk.dtb; fi; if test $board_name = MYS6ULL && test $board_rev = 14X14; then setenv fdt_file mys-imx6ull-14x14.dtb; fi; if test $fdt_file = undefined; then echo WARNING: Could not determine dtb to use; fi; fi;get_cmd=dhcpimage=zImageinitrd_addr=0x83800000initrd_high=0xffffffffip_dyn=yesloadaddr=0x80800000loadbootscript=fatload mmc ${mmcdev}{mmcpart} ${loadaddr} ${script};loadfdt=fatload mmc ${mmcdev}{mmcpart} ${fdt_addr} ${fdt_file}loadimage=fatload mmc ${mmcdev}{mmcpart} ${loadaddr} ${image}mfgtool_args=setenv bootargs console=${console},${baudrate} rdinit=/linuxrc g_mass_storage.stall=0 g_mass_storage.removable=1 g_mass_storage.file=/fat g_mass_storage.ro=1 g_mass_storage.idVendor=0x066F g_mass_storage.idProduct=0x37FF g_mass_storage.iSerialNumber="" clk_ignore_unused mmcargs=setenv bootargs console=${console},${baudrate} root=${mmcroot}mmcautodetect=yesmmcboot=echo Booting from mmc ...; run mmcargs; if test ${boot_fdt} = yes || test ${boot_fdt} = try; then if run loadfdt; then bootz ${loadaddr} - ${fdt_addr}; else if test ${boot_fdt} = try; then bootz; else echo WARN: Cannot load the DT; fi; fi; else bootz; fi;mmcdev=0mmcpart=1mmcroot=/dev/mmcblk0p2 rootwait rwnetargs=setenv bootargs console=${console},${baudrate} root=/dev/nfs ip=dhcp nfsroot=${serverip}{nfsroot},v3,tcpnetboot=echo Booting from net ...; run netargs; if test ${ip_dyn} = yes; then setenv get_cmd dhcp; else setenv get_cmd tftp; fi; ${get_cmd} ${image}; if test ${boot_fdt} = yes || test ${boot_fdt} = try; then if ${get_cmd} ${fdt_addr} ${fdt_file}; then bootz ${loadaddr} - ${fdt_addr}; else if test ${boot_fdt} = try; then bootz; else echo WARN: Cannot load the DT; fi; fi; else bootz; fi;panel=LCD050_800x480_Robescript=boot.scr /* bootcmd */ /* 先从bootscript启动，再mmc启动(加载zImage fdt，bootz启动)，其次net启动 */bootcmd=run findfdt;mmc dev ${mmcdev};mmc dev ${mmcdev};if mmc rescan; then if run loadbootscript; then run bootscript; else if run loadimage; then run mmcboot; else run netboot; fi; fi; else run netboot;fi;/* findfdt */ findfdt=if test $fdt_file = undefined; then if test $board_name = EVK && test $board_rev = 9X9; then setenv fdt_file imx6ull-9x9-evk.dtb; fi; if test $board_name = MYS6ULL && test $board_rev = 14X14; then setenv fdt_file mys-imx6ull-14x14.dtb; fi; if test $fdt_file = undefined; then echo WARNING: Could not determine dtb to use; fi; fi; 上一篇文章，uboot 屏幕源码解析，入口就是本文第二页 70 行代码，stdio_add_devices 指针函数。能看出来 uboot 屏幕源码只占 uboot 整个项目中很小的一部分，仅仅是一个环节而已。
代码注释有可能不对，以后单独看局部代码时候再修改增加完善注释，后续更新的话再另开一篇。本文可以看看 uboot 整个源码大概走向，这个是没有问题的，本文达成这个目标就好。
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uboot 完整源码追踪注释

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