Uboot 2015 代码解析5 board_init_r

从crt0.S的_main跳转至 board_init_r，此时已经在外部的ddr中运行此代码，完整的c语言环境已经建立完毕。

board_init_r接着进行后续外围硬件的初始化。

 

简介

board_init_r主要做了

1.外围硬件的初始化。

2.跳转至最终的main_loop命令行。

 

代码注释

void board_init_r(gd_t *id, ulong dest_addr)
{
    ulong malloc_start;
#if !defined(CONFIG_SYS_NO_FLASH)
    ulong flash_size;
#endif

    gd->flags |= GD_FLG_RELOC;  /* tell others: relocation done */    //搬运完成
    bootstage_mark_name(BOOTSTAGE_ID_START_UBOOT_R, "board_init_r");  //board_init_r mark

    monitor_flash_len = (ulong)&__rel_dyn_end - (ulong)_start;

    /* Enable caches */
    enable_caches();

    debug("monitor flash len: %08lX\n", monitor_flash_len);
    board_init();   /* Setup chipselects */
    /*
     * TODO: printing of the clock inforamtion of the board is now
     * implemented as part of bdinfo command. Currently only support for
     * davinci SOC's is added. Remove this check once all the board
     * implement this.
     */
#ifdef CONFIG_CLOCKS
    set_cpu_clk_info(); /* Setup clock information */
#endif
    serial_initialize(); //串口初始化

    debug("Now running in RAM - U-Boot at: %08lx\n", dest_addr);

#ifdef CONFIG_LOGBUFFER
    logbuff_init_ptrs(); //logbuff初始化
#endif
#ifdef CONFIG_POST
    post_output_backlog();
#endif

    /* The Malloc area is immediately below the monitor copy in DRAM */
    malloc_start = dest_addr - TOTAL_MALLOC_LEN;         // (16 * SZ_1M)
    mem_malloc_init (malloc_start, TOTAL_MALLOC_LEN);    // malloc初始化

#ifdef CONFIG_ARCH_EARLY_INIT_R
    arch_early_init_r(); //
#endif
    power_init_board();

#if !defined(CONFIG_SYS_NO_FLASH)  //include/configs/*.h
    puts("Flash: ");

    flash_size = flash_init();     //flash初始化
    if (flash_size > 0) {
# ifdef CONFIG_SYS_FLASH_CHECKSUM
        print_size(flash_size, "");
        /*
         * Compute and print flash CRC if flashchecksum is set to 'y'
         *
         * NOTE: Maybe we should add some WATCHDOG_RESET()? XXX
         */
        if (getenv_yesno("flashchecksum") == 1) { //计算flash的checksum
            printf("  CRC: %08X", crc32(0,
                (const unsigned char *) CONFIG_SYS_FLASH_BASE,
                flash_size));
        }
        putc('\n');
# else  /* !CONFIG_SYS_FLASH_CHECKSUM */
        print_size(flash_size, "\n");
# endif /* CONFIG_SYS_FLASH_CHECKSUM */
    } else {                                     //flash初始化失败
        puts(failed);
        hang();
    }
#endif

#if defined(CONFIG_CMD_NAND)   //NAND初始化
    puts("NAND:  ");
    nand_init();        /* go init the NAND */
#endif

#if defined(CONFIG_CMD_ONENAND) //ONE_NAND初始化
    onenand_init();
#endif

#ifdef CONFIG_GENERIC_MMC  //MMC初始化
    puts("MMC:   ");
    mmc_initialize(gd->bd);
#endif

#ifdef CONFIG_CMD_SCSI  //SCSI初始化
    puts("SCSI:  ");
    scsi_init();
#endif

#ifdef CONFIG_HAS_DATAFLASH //DATA_FLASH初始化
    AT91F_DataflashInit();
    dataflash_print_info();
#endif

    /* initialize environment */
    if (should_load_env()) //load env
        env_relocate();
    else
        set_default_env(NULL);

#if defined(CONFIG_CMD_PCI) || defined(CONFIG_PCI)  //PCI初始化
    arm_pci_init();
#endif

    stdio_init();   /* get the devices list going. */   //i2c/lcd/video/keyboard/硬件初始化

    jumptable_init();                                   //将函数指针放在malloc所在的堆区

#if defined(CONFIG_API)
    /* Initialize API */
    api_init();                                         //api回调函数初始化
#endif

    console_init_r();   /* fully init console as a device */   //串口彻底初始化

#ifdef CONFIG_DISPLAY_BOARDINFO_LATE
# ifdef CONFIG_OF_CONTROL
    /* Put this here so it appears on the LCD, now it is ready */
    display_fdt_model(gd->fdt_blob);                             //打印fdt的model到lcd屏幕上
# else
    checkboard();                                                //打印板子id
# endif
#endif

#if defined(CONFIG_ARCH_MISC_INIT)
    /* miscellaneous arch dependent initialisations */
    arch_misc_init();                                            //MISC 初始化
#endif
#if defined(CONFIG_MISC_INIT_R)
    /* miscellaneous platform dependent initialisations */
    misc_init_r();                                               //MISC 相关初始化 自定义
#endif

     /* set up exceptions */
    interrupt_init();                                            //初始化中断
    /* enable exceptions */
    enable_interrupts();                                         //中断使能

    /* Initialize from environment */
    load_addr = getenv_ulong("loadaddr", 16, load_addr);         //get load_addr

#ifdef CONFIG_BOARD_LATE_INIT
    board_late_init();                                           //board/freescale/board.c
#endif

#ifdef CONFIG_FSL_FASTBOOT
    fastboot_setup();                                            //fastboot安装
#endif
                                                                                                                                                                                                                                                                                                                   
#ifdef CONFIG_BITBANGMII
    bb_miiphy_init();                                            //MII初始化
#endif
#if defined(CONFIG_CMD_NET)                                     
    puts("Net:   ");
    eth_initialize(gd->bd);                                      //网口初始化
#if defined(CONFIG_RESET_PHY_R)
    debug("Reset Ethernet PHY\n");
    reset_phy();                                                 //reset phy
#endif
#endif

#ifdef CONFIG_POST
    post_run(NULL, POST_RAM | post_bootmode_get(0));             //测试含POST_RAM flag的测试项, 以及之前指定的需要测试的部分.
#endif

#if defined(CONFIG_PRAM) || defined(CONFIG_LOGBUFFER)
    /*
     * Export available size of memory for Linux,
     * taking into account the protected RAM at top of memory
     */
    {
        ulong pram = 0;                                                        //pram
        uchar memsz[32];

#ifdef CONFIG_PRAM
        pram = getenv_ulong("pram", 10, CONFIG_PRAM);                          //get pram
#endif
#ifdef CONFIG_LOGBUFFER
#ifndef CONFIG_ALT_LB_ADDR
        /* Also take the logbuffer into account (pram is in kB) */
        pram += (LOGBUFF_LEN + LOGBUFF_OVERHEAD) / 1024;                       //pram += (LOGBUFF_LEN + LOGBUFF_OVERHEAD) / 1024;
#endif
#endif
        sprintf((char *)memsz, "%ldk", (gd->ram_size / 1024) - pram);       
        setenv("mem", (char *)memsz);                                          //mem = (gd->ram_size / 1024) - pram)
    }
#endif

#ifdef CONFIG_FSL_FASTBOOT
    check_fastboot();                                                          //run cmd fastboot
#endif

    /* main_loop() can return to retry autoboot, if so just run it again. */
    for (;;) {
        main_loop();
    }

    /* NOTREACHED - no way out of command loop except booting */
}