MTK （android 开机）Android开机流程解析

最新推荐文章于 2025-06-08 09:11:02 发布

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本文介绍了嵌入式系统的早期初始化过程，包括平台硬件初始化、UART初始化、中断配置等，并详细解释了启动模式的选择和相应的处理流程。

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//平台相关早期初始化，如获取板级信息，初始化时钟、中断、定时器等
/*
      平台硬件早期初始化，包括irq、timer，wdt，uart，led，pmic(电压管理芯片)，i2c，gpio等,
       初始化平台硬件，建立lk基本运行环境。
   */

1. void platform_early_init(void)

{

    /* initialize the uart */
    uart_init_early();
    platform_init_interrupts();
    platform_early_init_timer();
    mt_gpio_set_default();

     mtk_wdt_init();
    #ifdef LK_PROFILING
    dprintf(INFO,"[PROFILE] ------- WDT Init takes %d ms -------- \n", (int)get_timer(time_wdt_early_init));

    g_fb_size = mt_disp_get_vram_size();
    g_fb_base = memory_size() - g_fb_size + DRAM_PHY_ADDR;
    dprintf(INFO, "FB base = 0x%x, FB size = %d\n", g_fb_base, g_fb_size);

    //FIXME: Disable for MT6582 FPGA Ealry Porting
    #ifndef DISABLE_DISPLAY_IN_LK_FOR_82_BRINGUP
    if (!(lcm_params->type==LCM_TYPE_DSI && lcm_params->dsi.mode ==CMD_MODE))
        {printf("tony:will mt_disp_init...000\n");
        mt_disp_init((void *)g_fb_base);
      }
     #endif

}

/*
包括nand/emmc，显现相关驱动，启动模式选择，加载logo资源检测是否DA模式，
检测分区中是否有KE信息，如果就KE信息，就从分区load 到DRAM，点亮背光，
显示logo，禁止I/D-cache和MMU,跳转到DA（??）,配置二级cache的size 获取bat电压，
判断是否低电量是否显示充电logo等
*/

2.void platform_init(void)
{

    #ifdef MTK_EMMC_SUPPORT
    mmc_legacy_init(1);
    #else
    #ifndef MACH_FPGA
    nand_init();
    nand_driver_test();

      #ifdef MTK_KERNEL_POWER_OFF_CHARGING ///关机充电模式
       if((g_boot_arg->boot_reason == BR_USB) && (upmu_is_chr_det() == KAL_FALSE))
       {
       printf("[%s] Unplugged Charger/Usb between Pre-loader and Uboot in Kernel Charging Mode, Power Off \n",

       __func__);
       mt6575_power_off();
       }
       #endif

env_init();
print_env();

mboot_common_load_logo((unsigned long)mt_get_logo_db_addr(), "logo");///加载logo

       mt_disp_fill_rect(0, 0, CFG_DISPLAY_WIDTH, CFG_DISPLAY_HEIGHT, 0x0);//0->f///显示背景图片
       mt_disp_power(TRUE);
       mt_disp_update(0, 0, CFG_DISPLAY_WIDTH, CFG_DISPLAY_HEIGHT);
       mt_disp_wait_idle();
       mt_disp_update(0, 0, CFG_DISPLAY_WIDTH, CFG_DISPLAY_HEIGHT);
       mt_disp_wait_idle();
       mt_disp_power(1);           //power on display related modules

mt65xx_backlight_on(); ///delete by tony /////////////打开背光

boot_mode_select();//////////////选择启动模式！！！--很重要

if (g_boot_arg->boot_mode == DOWNLOAD_BOOT)///////若是DOWNLOAD_BOOT模式

     {
   printf("[LK] boot mode is DOWNLOAD_BOOT\n");

      #ifdef MTK_SECURITY_SW_SUPPORT
   /* verify da before jumping to da*/
   if (sec_usbdl_enabled()) {
        u8 *da_addr = (u8 *)g_boot_arg->da_info.addr;
        u32 da_len   = g_boot_arg->da_info.len;
        u32 sig_len = g_boot_arg->da_info.sig_len;
        u8 *sig_addr = (unsigned char *)da_addr + (da_len - sig_len);

        if (da_len == 0 || sig_len == 0) {
       printf("[LK] da argument is invalid\n");
       printf("da_addr = 0x%x\n", da_addr);
       printf("da_len = 0x%x\n", da_len);
       printf("sig_len = 0x%x\n", sig_len);
        }

        if (sec_usbdl_verify_da(da_addr, (da_len - sig_len), sig_addr, sig_len)) {
       /* da verify fail */
                video_printf(" => Not authenticated tool, download stop...\n");
       while(1); /* fix me, should not be infinite loop in lk */
        }
   }
   else
#endif
   {
        printf(" DA verification disabled...\n");
   }
        mt_disp_show_boot_logo();
        video_printf(" => Downloading...\n");
        mt65xx_backlight_on();
        mtk_wdt_disable();//Disable wdt before jump to DA
        platform_uninit();
#ifdef HAVE_CACHE_PL310
        l2_disable();
#endif

#ifdef ENABLE_L2_SHARING
        config_shared_SRAM_size();
#endif
        arch_disable_cache(UCACHE);
        arch_disable_mmu();
        jump_da(g_boot_arg->da_info.addr, g_boot_arg->da_info.arg1, g_boot_arg->da_info.arg2);
    }

}

mt65xx_bat_init(); //电池初始化

if(kernel_charging_boot() == 1)///////若是DOWNLOAD_BOOT模式

       {
#ifdef MTK_BATLOWV_NO_PANEL_ON_EARLY
       CHARGER_TYPE CHR_Type_num = CHARGER_UNKNOWN;
       charging_get_charger_type(&CHR_Type_num);
       if ((g_boot_mode != LOW_POWER_OFF_CHARGING_BOOT) ||
       ((CHR_Type_num != STANDARD_HOST) && (CHR_Type_num != NONSTANDARD_CHARGER)))
       {
           dprintf(INFO, "[PROFILE] ------- g_boot_mode = %d -------- \n", g_boot_mode);
#endif
       mt_disp_power(TRUE);
       mt_disp_show_low_battery();
       mt_disp_wait_idle();
       mt65xx_leds_brightness_set(6, 110);
#ifdef MTK_BATLOWV_NO_PANEL_ON_EARLY
       }
#endif
   }

           if(kernel_charging_boot() == 1)   ///////若是关机充电模式
   {
#ifdef MTK_BATLOWV_NO_PANEL_ON_EARLY
       CHARGER_TYPE CHR_Type_num = CHARGER_UNKNOWN;
       charging_get_charger_type(&CHR_Type_num);
       if ((g_boot_mode != LOW_POWER_OFF_CHARGING_BOOT) ||
       ((CHR_Type_num != STANDARD_HOST) && (CHR_Type_num != NONSTANDARD_CHARGER)))
       {
           dprintf(INFO, "[PROFILE] ------- g_boot_mode = %d -------- \n", g_boot_mode);
#endif
       mt_disp_power(TRUE);
       mt_disp_show_low_battery();
       mt_disp_wait_idle();
       mt65xx_leds_brightness_set(6, 110);
#ifdef MTK_BATLOWV_NO_PANEL_ON_EARLY
       }
#endif
   }

       else if(g_boot_mode != KERNEL_POWER_OFF_CHARGING_BOOT && g_boot_mode != LOW_POWER_OFF_CHARGING_BOOT)     ///////若是正常的模式
   {
#ifndef DISABLE_DISPLAY_IN_LK_FOR_82_BRINGUP
       if (g_boot_mode != ALARM_BOOT && (g_boot_mode != FASTBOOT))
       {
                printf("tony:in 2222:will mt_disp_show_boot_logo\n");
           mt_disp_show_boot_logo();
       }
#endif
   }

      #else    ///////若是其他的模式
#ifndef DISABLE_DISPLAY_IN_LK_FOR_82_BRINGUP
   if (g_boot_mode != ALARM_BOOT && (g_boot_mode != FASTBOOT))
   {      //printf("tony:in 3333:will mt_disp_show_boot_logo \n");
       mt_disp_show_boot_logo();
   }
#endif
#endif

printf("tony:will invoke sw_env( )\n");////打印出各种启动模式：normal mode，fastboot mode，meta mode，etc
sw_env(); ====>>>>具体实现：

      #ifndef USER_BUILD
    switch (g_boot_mode)
   {
      case META_BOOT:
          video_printf(" => META MODE\n");
          break;
      case FACTORY_BOOT:
          video_printf(" => FACTORY MODE\n");
          break;
      case RECOVERY_BOOT:
          video_printf(" => RECOVERY MODE\n");
          break;
      case SW_REBOOT:
          //video_printf(" => SW RESET\n");
          break;
      case NORMAL_BOOT:
       printf("tony:in sw_env( )==>> case NORMAL_BOOT.... \n");
          //if(g_boot_arg->boot_reason != BR_RTC && get_env("hibboot") != NULL && atoi(get_env("hibboot")) == 1)
          if(get_env("hibboot") != NULL && atoi(get_env("hibboot")) == 1)
              video_printf(" => HIBERNATION BOOT\n");
          else
              video_printf(" => NORMAL BOOT\n");
          break;
      case ADVMETA_BOOT:
          video_printf(" => ADVANCED META MODE\n");
          break;
      case ATE_FACTORY_BOOT:
          video_printf(" => ATE FACTORY MODE\n");
          break;
#if defined (MTK_KERNEL_POWER_OFF_CHARGING)
   case KERNEL_POWER_OFF_CHARGING_BOOT:
       video_printf(" => POWER OFF CHARGING MODE\n");
       break;
   case LOW_POWER_OFF_CHARGING_BOOT:
       video_printf(" => LOW POWER OFF CHARGING MODE\n");
       break;
#endif
      case ALARM_BOOT:
          video_printf(" => ALARM BOOT\n");
          break;
      case FASTBOOT:
          video_printf(" => FASTBOOT mode...\n");
          break;
      default:
          video_printf(" => UNKNOWN BOOT\n");
    }
    return;
#endif