sbl1_entry_init_stack:
  // -------------------------------
  // add more assembly init code here for entering sbl1_main_ctl//
  // restore PBL parameter and enter sbl1_main_ctl
  // -------------------------------
MOVw0,w7BLsbl1_main_ctl    //跳转到C环境继续

voidsbl1_main_ctl(boot_pbl_shared_data_type *pbl_shared){
  DALResultbsy_wait_init;

  /* Configure Domain access control register */
mmu_set_dacr(DACR_ALL_DOMAIN_CLIENTS); //配置域访问控制器

  /* Retrieve info passed from PBL*/
sbl1_retrieve_shared_info_from_pbl(pbl_shared); //将pbl传过来的信息保存到pbl_shared

  /* Initialize shared functions structure - provides other images with function pointers in Loader */
boot_shared_functions_register(); //初始化共享函数结构

  /* Initialize SBL memory map */
sbl1_populate_initial_mem_map(&bl_shared_data); //初始化SBL内存映射

  /* Calculate the SBL start time for use during boot logger initialization. */
sbl_start_time =CALCULATE_TIMESTAMP(HWIO_IN(TIMETICK_QTIMER_CLK));
sbl_start_time_mpm =CALCULATE_MPM_TIMESTAMP(HWIO_IN(TIMETICK_CLK));

  /* Initialize busywait module Note: required before logger init due to uart driver dependency on busywait */
BL_VERIFY((bsy_wait_init=boot_busywait_init()) ==DAL_SUCCESS, (uint16)bsy_wait_init|BL_ERROR_GROUP_BUSYWAIT);

  /* Enable qdss workaround*/
BL_VERIFY(boot_clock_debug_init() ==TRUE,FALSE|BL_ERROR_GROUP_CLK );

  /* Enter debug mode if debug cookie is set */
sbl1_debug_mode_enter(); //sbl1 debug mode，其实就是一个while,知道jtag获取到地址。判断cookie是否匹配，以确定是否进入jtag调试模式

  /* Initialize the stack protection canary */
boot_init_stack_chk_canary();//堆栈保护，随机初始化多出数值，避免堆栈溢出攻击

  /* Initialize boot shared imem */
boot_shared_imem_init(&bl_shared_data);
  //进行SBL间数据共享初始化，数据类型bl_shared_data_type，先进行溢出判断，检查魔数是否匹配，否则写0xFF,并更新版本和魔数值

  /* Initialize the ChipInfo driver */
ChipInfo_Init();

  /* Initialize the QSEE interface */
sbl1_init_sbl_qsee_interface(&bl_shared_data, &sbl_verified_info);
  //初始化QSEE(Secure Excution Environment)安全执行环境接口，清零interface，初始化完成后并为QSEE接口分配魔数和version号以及复位请求，调用boot_ddr_enter_self_refresh进行DDR自我更新和调用boot_ddr_exit_self_refresh退出自我更新。并使用PBL提供的验证信息更新QSEE的接口。更新bl_shared_data中的qsee中的boot_image_entry入口点。QSEE一般是为APP提供安全运行环境，它将整体系统分为安全运行环境和常规运行环境，像指纹识别、人脸识别均需要运行在安全环境下，而像普通APP则运行在常规环境下，QSEE一般和Trust Zone共同完成安全运行环境和常规运行环境的搭建
  /* Initialize dal heap using internal memory */
boot_DALSYS_HeapInit(boot_internal_heap,BOOT_INTERNAL_HEAP_SIZE,FALSE);

  /*Initialize DAL, needs to be called before modules that uses DAL */
boot_DALSYS_InitMod(NULL);

  /* Initialize boot logger and start the log timer.
     This must be done after sbl1_retrieve_shared_info_from_pbl
     and boot_secboot_ftbl_init. */
sbl1_boot_logger_init(&boot_log_data,pbl_shared);
  //配置GPIO使能串口，调用sbl1_boot_logger_init进行串口及定时器和相关log初始化，便于boot_log_message打印log信息。串口硬件初始化：sbl1_boot_logger_init-> boot_log_init-> boot_log_init_uart-> boot_uart_init> uart_initialize-> uart_open(&uart_debug_handle, UART_DEBUG_PORT, &c)，最后一个函数位于QomPkg/Library/UartQupv3Lib/UartXBL.c, 函数内调用UART_LOG_0(INFO,"+uart_open")打印串口开启log，有待探究，uart_open调用register_init函数配置寄存器，函数内调用REG_OUT;配置相关寄存器。

boot_log_set_meta_info(boot_log_data.meta_info_start);

  /* Set hash algorithm */
BL_VERIFY(boot_set_hash_algo(SBL_HASH_SHA256) ==BL_ERR_NONE,BL_ERR_UNSUPPORTED_HASH_ALGO|BL_ERROR_GROUP_BOOT);

  /* Call sbl1_hw_init to config pmic device so we can use PS_HOLD to reset */
sbl1_hw_init();
  //硬件初始化，调用boot_Tsens_Init初始化温度传感器；调用boot_qusb_ldr_utils_hs_phy_nondrive_mode_set将高速QUSB2置位为非驱动模式；IIC时钟初始化，因为EEPROM使用IIC协议，初始化IIC时钟来确保后面的EEPROM能够得到正常的初始化。首先根据宏定义FEATURE_BOOT_FAST_DEBUG判断是否进入debug mode->boot_debug_mode_enter();

#if defined (FEATURE_DEVICEPROGRAMMER_IMAGE) || defined (FEATURE_DDI_IMAGE)
  /* Enter device programmer does not return */
device_programmer_init(&bl_shared_data,pbl_shared);
#else/* Store the sbl1 hash to shared imem */
boot_store_tpm_hash_block(&bl_shared_data, &sbl_verified_info);

  /*-----------------------------------------------------------------------
    Process the target-dependent SBL1 procedures
  -----------------------------------------------------------------------*/
boot_config_process_bl(&bl_shared_data,SBL1_IMG,sbl1_config_table);
#endif

} /* sbl1_main_ctl() */

boot_config_process_bl->boot_config_process_entry->boot_do_procedures->

#define BOOT_FUNCTION_LEN 48
void boot_do_procedures
(
  bl_shared_data_type *bl_shared_data,
  boot_function_table_type *procs
)
{
  boot_function_table_type *cur_proc;
  uint32 func_start_time=0;
  char func_name[BOOT_FUNCTION_LEN];

  BL_VERIFY( bl_shared_data != NULL, BL_ERR_NULL_PTR_PASSED|BL_ERROR_GROUP_BOOT );

  if (procs != NULL)
  {
    for ( cur_proc = procs; (boot_procedure_func_type)cur_proc->func != NULL; cur_proc++ )
    {
      func_start_time = boot_log_get_time();
      ((boot_procedure_func_type)cur_proc->func)( bl_shared_data );
      qsnprintf(func_name, BOOT_FUNCTION_LEN ,"%s", cur_proc->func_name);
      boot_log_delta_time(func_start_time,func_name);//这边会打印log
    }
  }
}
//我们需要看这个sbl_config_table，他是在sbl_config.c中配置的
boot_configuration_table_entry sbl1_config_table[] =
{
/* host_img_id host_img_type target_img_id target_img_type target_img_sec_type        load   auth   exec   jump   exec_func jump_func   pre_procs       post_procs         load_cancel              target_img_partition_id         target_img_str            boot_ssa_enabled enable_xpu xpu_proc_id sbl_qsee_interface_index seg_elf_entry_point whitelist_ptr */
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_APDP_SW_TYPE,        TRUE,  TRUE,  FALSE, FALSE, NULL, NULL,           apdp_pre_procs, apdp_post_procs,   apdp_load_cancel,        apdp_partition_id,              APDP_BOOT_LOG_STR,        FALSE, FALSE, 0x0, 0x0, 0x0,                    apdp_img_whitelist    },
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_OEM_MISC_SW_TYPE,    TRUE,  TRUE,  FALSE, FALSE, NULL, NULL,           NULL,           NULL,              oem_misc_load_cancel,    multi_image_partition_id,       OEM_MISC_BOOT_LOG_STR,    FALSE, FALSE, 0x0, 0x0, 0x0,                    oem_misc_img_whitelist},
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_QTI_MISC_SW_TYPE,    TRUE,  TRUE,  FALSE, FALSE, NULL, NULL,           NULL,           NULL,              qti_misc_load_cancel,    multi_image_qti_partition_id,   QTI_MISC_BOOT_LOG_STR,    FALSE, FALSE, 0x0, 0x0, 0x0,                    qti_misc_img_whitelist},
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_RPM_FW_SW_TYPE,      TRUE,  TRUE,  FALSE, FALSE, NULL, NULL,           rpm_pre_procs,  NULL,              rpm_load_cancel,         rpm_partition_id,               RPM_BOOT_LOG_STR,         FALSE, FALSE, 0x0, 0x0, 0x0,                    rpm_img_whitelist     },
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_QSEE_DEVCFG_SW_TYPE, TRUE,  TRUE,  FALSE, FALSE, NULL, NULL,           NULL,           NULL,              qsee_devcfg_load_cancel, qsee_devcfg_image_partition_id, QSEE_DEVCFG_BOOT_LOG_STR, FALSE, FALSE, 0x0, 0x0, 0x0,                    devcfg_img_whitelist  },
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_QSEE_SW_TYPE,        TRUE,  TRUE,  FALSE, FALSE, NULL, NULL,           NULL,           qsee_post_procs,   NULL,                    qsee_partition_id,              QSEE_BOOT_LOG_STR,        FALSE, FALSE, 0x0, 0x0, 0x0,                    qsee_img_whitelist    },
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_SEC_SW_TYPE,         TRUE,  TRUE,  FALSE, FALSE, NULL, NULL,           NULL,           NULL,              sec_load_cancel,         secdata_partition_id,           SEC_BOOT_LOG_STR,         FALSE, FALSE, 0x0, 0x0, 0x0,                    sec_img_whitelist     },
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_QHEE_SW_TYPE,        TRUE,  TRUE,  FALSE, FALSE, NULL, NULL,           NULL,           NULL,              NULL,                    qhee_partition_id,              QHEE_BOOT_LOG_STR,        FALSE, FALSE, 0x0, 0x0, 0x0,                    qhee_img_whitelist    },
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_WDT_SW_TYPE,         TRUE,  TRUE,  FALSE, TRUE,  NULL, sti_jump_func,  NULL,           NULL,              sti_load_cancel,         sti_partition_id,               STI_BOOT_LOG_STR,         FALSE, FALSE, 0x0, 0x0, 0x0,                    sti_img_whitelist     },
  {SBL1_IMG, CONFIG_IMG_QC, GEN_IMG, CONFIG_IMG_ELF,     SECBOOT_APPSBL_SW_TYPE,      TRUE,  TRUE,  FALSE, TRUE,  NULL, qsee_jump_func, NULL,           appsbl_post_procs, appsbl_load_cancel,      appsbl_partition_id,            APPSBL_BOOT_LOG_STR,      FALSE, FALSE, 0x0, 0x0, SCL_XBL_CORE_CODE_BASE, xbl_core_img_whitelist},
  {NONE_IMG, }
};

//boot_do_procedures函数会按照这个表循环去执行相应的func，以第一个为例
//第一个循环的func为apdp_pre_procs
boot_function_table_type apdp_pre_procs[] =
{
  /* Initialize the flash device */
  {boot_flash_init, "boot_flash_init"}, //func: boot_flash_init, name: boot_flash_init

  /* Initialize XBL config Lib */
  {sbl1_xblconfig_init, "sbl1_xblconfig_init"},

  /*Initialize feature configuration from xbl config image*/
  {sbl1_feature_config_init,"sbl1_feature_config_init"},

  /* Initialize the default CDT before reading CDT from flash */
  {boot_config_data_table_default_init, "boot_config_data_table_default_init"},

  /* Set default DDR params */
  {sbl1_ddr_set_default_params, "sbl1_ddr_set_default_params"},

  /* Copy the configure data table from flash */
  {boot_config_data_table_init, "boot_config_data_table_init"},

  /* Store platform id */
  {sbl1_hw_platform_pre_ddr, "sbl1_hw_platform_pre_ddr"},

  /* Initialize PMIC and railway driver */
  {sbl1_hw_pre_ddr_init, "sbl1_hw_pre_ddr_init"},

  /* Check if forced dload timeout reset cookie is set */
  {boot_dload_handle_forced_dload_timeout, "boot_dload_handle_forced_dload_timeout"},

  /* Configure ddr parameters based on eeprom CDT table data. */
  {sbl1_ddr_set_params, "sbl1_ddr_set_params"},

  /* Initialize DDR */
  {sbl1_ddr_init, "sbl1_ddr_init"},

  /* Train DDR if applicable */
  {sbl1_do_ddr_training, "sbl1_do_ddr_training"},

  /*----------------------------------------------------------------------
   Run deviceprogrammer if compiling the deviceprogrammer_ddr image.
   In XBL builds the function below is stubbed out (does nothing)
  ----------------------------------------------------------------------*/
  {sbl1_hand_control_to_devprog_ddr_or_ddi, "sbl1_hand_control_to_devprog_ddr_or_ddi"},

#ifndef FEATURE_DEVICEPROGRAMMER_IMAGE

  /* Initialize SBL1 DDR ZI region, relocate boot log to DDR */
  {sbl1_post_ddr_init, "sbl1_post_ddr_init"},

  {sbl1_hw_init_secondary, "sbl1_hw_init_secondary"},

#endif /*FEATURE_DEVICEPROGRAMMER_IMAGE*/

  /* Last entry in the table. */
  NULL
};

//这也正好对应着串口lo中后续的log
D -        11 - boot_flash_init

static int abs(int x) { return x >= 0 ? x : -x; }

pm_err_flag_type
pm_device_init ( void )
{
   static pm_err_flag_type err_flag = PM_ERR_FLAG_SUCCESS;
   uint32 initial_num_spmi_transn = pm_get_num_spmi_transaction(0);

   err_flag |= pm_device_setup();//SPMI bus初始化

   pm_target_information_init();

   if( (pm_is_target_pre_silicon() == TRUE) && (pm_is_pmic_present(PMIC_A) == FALSE) )
   {
      pm_log_message("Bootup: No PMIC on RUMI Target");
      return err_flag = PM_ERR_FLAG_SUCCESS;
   }

   pm_comm_info_init();

   err_flag |= pm_device_pre_init();

   err_flag |= pm_pon_init(); //PON机制的初始化

   err_flag |= pm_pbs_info_rom_init();  /* Read PBS INFO for the pmic rom devices */

   err_flag |= pm_sbl_pre_config(); /* SBL Pre Configuration */

   err_flag |= pm_sbl_config(); /* SBL Configuration */
   if (err_flag == PM_ERR_FLAG_SUCCESS)
   {
      pm_ram_image_loaded_flag = TRUE;
   }

   err_flag |= pm_sbl_config_test(); /* SBL Configuration validation, only executes complete code if spare reg 0x88F bit 0 is set*/

   err_flag |= pm_pbs_info_ram_init();  /* Read PBS INFO for the pmic ram devices */

   err_flag |= pm_pbs_ram_version_validation_test(); /* PBS RAM Version validation, only executes complete code if spare reg 0x88F bit 0 is set*/

   err_flag |= pm_device_post_init(); /* Initialize PMIC with the ones PDM can not perform */

  //Write to Spare bit for pm_device_init_status
   if(err_flag == PM_ERR_FLAG_SUCCESS)
   {
      err_flag = pm_comm_write_byte_mask(PMIC_A_SLAVEID_PRIM, PMIO_PON_PERPH_RB_SPARE_ADDR, PON_PERPH_RB_SPARE_DEVICE_INIT_MASK,PON_PERPH_RB_SPARE_DEVICE_INIT_MASK, 0);
   }

   pm_log_message("Device Init # SPMI Transn: %d", pm_get_num_spmi_transaction(initial_num_spmi_transn));
   return err_flag; /* NON ZERO return means an ERROR */
}

#include <AsmMacroIoLibV8.h>
#include <Base.h>
#include <Library/PcdLib.h>
#include <AutoGen.h>

    AREA    |.text|,ALIGN=8,CODE,READONLY

    IMPORT CEntryPoint// 导入CEntryPoint()函数
    EXPORT _ModuleEntryPoint// 输出 _ModuleEntryPoint段
    IMPORT ArmWriteCpacr// 导入InitStackCanary()函数 初始化栈
    IMPORT ArmEnableInstructionCache//导入ArmDisableInterrupts()函数 禁用arm 中断
    IMPORT ArmInvalidateInstructionCache// 导入ArmDisableCachesAndMmu()函数 禁用cache, mmu
    IMPORT ArmInvalidateTlb
    IMPORT ArmEnableDataCache
    IMPORT InitStackCanary

  IMPORT  ArmDisableInterrupts
  IMPORT  ArmDisableCachesAndMmu
  IMPORT  ArmWriteCptr
  IMPORT  ArmDisableAlignmentCheck
  IMPORT  ArmWriteHcr
  IMPORT  ArmWriteVBar
  IMPORT  ArmInvalidateDataCache

// TODO - JDG
    EXPORT _StackBase
    EXPORT _StackSize
    EXPORT CNTFRQ

_StackBase
  dcq FixedPcdGet64(PcdPrePiStackBase)

_StackSize
  dcq FixedPcdGet64(PcdPrePiStackSize)

CNTFRQ
  dcq FixedPcdGet32(PcdArmArchTimerFreqInHz)

_ModuleEntryPoint
  mov x0, #0
  /* First ensure all interrupts are disabled */
  bl ArmDisableInterrupts        //关闭所有的中断

  /* Ensure that the MMU and caches are off */
  bl ArmDisableCachesAndMmu        //关闭MMU和caches

  /* Invalidate Instruction Cache and TLB */
  bl ArmInvalidateInstructionCache    //关闭TLB

  bl ArmInvalidateTlb

  /* Get current EL in x0 */
  //获得当前运行的安全环境：EL1、EL2、EL3
  EL1_OR_EL2_OR_EL3(x0)
// CurrentEL : 0xC = EL3; 8 = EL2; 4 = EL1
// This only selects between EL1 and EL2 and EL3, else we die.
// Provide the Macro with a safe temp xreg to use.
        //mrs    x0, CurrentEL
        cmp    x0, #0xC// 比较 x0寄存器是否为 0xc，如果是跳转到 标签3
        beq   %F3
        cmp    x0, #0x8// 比较 x0寄存器是否为 0x8，如果是跳转到 标签2
        beq   %F2
        cmp    x0, #0x4// 比较 x0寄存器是否为 0x4
        bne   .                    // We should never get here
// EL1 code starts here

1  beq _Start
2  beq _Start// 如果当前是 EL2，直接跳转到_Start

  /* Do not trap any access to Floating Point and Advanced SIMD in EL3. */
  /* Note this works only in EL3, x0 has current EL mode */
3  mov x0, #0
  bl ArmWriteCptr// 如果当前是 EL3，直接跳转到ArmWriteCptr

//初始化ELX 安全环境
_SetupELx
  mov x0, #0x30           /* RES1 */// x0 = 0x30
  orr x0, x0, #(1 << 0)   /* Non-secure bit */// 使能第0位为1
  orr x0, x0, #(1 << 8)   /* HVC enable */// 使能第8位为1
  orr x0, x0, #(1 << 10)  /* 64-bit EL2 */// 使能第10位为1
  msr scr_el3, x0

// ...
// ...
// ...

//使能 Cache
_EnableCache
#ifdef PRE_SIL
  LoadConstantToReg (FixedPcdGet32(PcdSkipEarlyCacheMaint), x0)
  cmn x0, #0
b.ne _PrepareArguments
#endif
  bl ArmInvalidateDataCache
  bl ArmEnableInstructionCache
  bl ArmEnableDataCache

//初始化栈
_PrepareArguments
  /* Initialize Stack Canary */
  bl InitStackCanary

//调用 CEntryPoint，传参 _StackBase、_StackSize
  /* x0 = _StackBase and x1 = _StackSize */
  ldr x0, _StackBase     /* Stack base arg0 */
  ldr x1, _StackSize     /* Stack size arg1 */
  bl CEntryPoint //进入C

dead
  b dead                      /* We should never get here */

END

VOIDMain (INVOID  *StackBase,INUINTNStackSize){
EFI_STATUSStatus =EFI_NOT_READY;
UefiInfoBlkType*UefiInfoBlkPtr =NULL;
UINT64UefiFdBase = 0,SecHeapMemBase = 0;
UINTNSecHeapAslrVal = 0;
UINTNHobStackSize;
UINTNUARTLogBufferSize = 0;
UINTN            *UARTLogBufferPtr;
MemRegionInfoDxeHeapMemInfo;
UINTNDxeHeapAslrVal = 0;

gReset =GetTimeInNanoSecond(GetPerformanceCounter());
  //获得fdf文件所在的地址，fdf可以说是UEFI的配置文件
  //在fdf文件中包含所有的inf文件所在路径，及相关的bmp图片资源路径，以及相关的cfg配置文件路径UefiFdBase =FixedPcdGet64(PcdEmbeddedFdBaseAddress);
SecHeapMemBase =UefiFdBase +SEC_HEAP_MEM_OFFSET;
HobStackSize =StackSize;

gStackBase =StackBase;

  /* Start UART debug output */
UartInit();    //初始化串口

PrintUefiStartInfo(); //打印一些串口log
  //这边加了log 来确定M7项目的UefiFdBase，StackBase，StackSize
  //LIUQI: gStackBase = 0x000000005FF90000
  //LIUQI: StackSize = 0x000000000003FD00
  //LIUQI: UefiFdBase = 0x000000005FC00000
  SerialPrint("LIUQI: gStackBase = 0x%016lx\\n", gStackBase);
  SerialPrint("LIUQI: StackSize = 0x%016lx\\n", StackSize);
  SerialPrint("LIUQI: UefiFdBase = 0x%016l\\nx", UefiFdBase);

  /* Get nibble from random value to adjust SEC heap */
SecHeapAslrVal =AslrAdjustRNGVal(ASLR_HEAP_RNG_BITS);

InitHobList(SecHeapMemBase,
SEC_HEAP_MEM_SIZE - (SecHeapAslrVal*ASLR_HEAP_ALIGN),
UefiInfoBlkPtr);

  // Need memory allocation working
InitializeCpuExceptionHandlers (NULL); //初始化CPU异常处理入口PrintTimerDelta(); //打印从开机到现在的时间差

  /* Enable program flow prediction, if supported *///  ArmEnableBranchPrediction ();/* Initialize Info Block */
UefiInfoBlkPtr =InitInfoBlock (UefiFdBase +UEFI_INFO_BLK_OFFSET);
UefiInfoBlkPtr->StackBase =StackBase;
UefiInfoBlkPtr->StackSize =StackSize;

  //初始化 RAM 分区表InitRamPartitionTableLib ();

ValidateFdRegion(UefiFdBase);

  /* Add the FVs to the hob list */
  //初始化hoblist，有关hob可参考：<https://opqqrjk1dc.feishu.cn/wiki/wikcnabfL0g6PS10ctRWRfzX9bcBuildFvHob> (PcdGet64(PcdFlashFvMainBase),PcdGet64(PcdFlashFvMainSize));

  /* Should be done after we have setup HOB for memory allocation  */
  //打印RAM 分区信息PrintRamPartitions ();

  //初始化cacheStatus =EarlyCacheInit (UefiFdBase,UEFI_FD_SIZE);

  /* Load and Parse platform cfg file, cache re-initialized per cfg file */
  //加载并解析 uefiplat.cfg平台配置文件Status =LoadAndParsePlatformCfg();

  //更新系统内存区相关信息
  /* Add information from all other memory banks */
Status =UpdateSystemMemoryRegions();
  /* Initialize cache for all memory regions */
Status =InitCacheWithMemoryRegions();

  //初始化所有的共享库
  /* All shared lib related initialization */
Status =InitSharedLibs();

  //获得DXE Heap堆内存信息，uefiplat.cfg中定义的Status =GetMemRegionInfoByName("DXE Heap", &DxeHeapMemInfo);

  /* Get nibble from random value to adjust DXE heap */
DxeHeapAslrVal =AslrAdjustRNGVal(ASLR_HEAP_RNG_BITS);

  /* Re-initialize HOB to point to the DXE Heap in CFG */
ReInitHobList(DxeHeapMemInfo.MemBase,
DxeHeapMemInfo.MemSize - (DxeHeapAslrVal*ASLR_HEAP_ALIGN),
UefiInfoBlkPtr);

    /* Update UART log buffer size if specififed in uefiplat else allocate 32KB of serial buffer in DXE Heap. */
  //在uefiplat.cfg中定义，可以调整uart的buffer size,目前M7此项注释掉了
Status =GetConfigValue ("UARTLogBufferSize", (UINT32*) &UARTLogBufferSize);

  // Allocate Runtime Pool
  //初始化分页池缓存区UARTLogBufferPtr =AllocatePagesRuntimeServiceData(EFI_SIZE_TO_PAGES(UARTLogBufferSize));

  /* Prevent Reinitializing of Serial Buffer */
SerialBufferReInitLock();

  /* Now we have access to bigger pool, move pre-pi memory allocation pool to it */
ReInitPagePoolBuffer ();

InitSplitBoot (&UefiBootContinue, 0);  // Doesn't return if succeeds

UefiBootContinue (0);  // Just continue booting explicitly if returns or on failure
}

EFI_STATUSEFIAPILoadAndParsePlatformCfg (VOID ){
EFI_STATUSStatus;
INTNMemParserDesc = 0;
UINT8      *CfgBuffer =NULL;
UINTNFileSize = 0;

  //1.初始化相关全局变量InitGlobals();
  //2. 加载并解析 uefiplat.cfg 配置文件Status =LoadFileFromFV0 (UEFIPLATCFG_FILE, &CfgBuffer, &FileSize);

MemParserDesc =OpenParser (CfgBuffer,FileSize,NULL);

  /* Reset Global for RAM load */
mMemRegions =NULL;
mNumMemRegions = 0;
  //3. 解析uefiplat.cfg 中的 [Config] 区域EnumKeyValues (MemParserDesc, (UINT8*)"Config",ProcessConfigTokens)
MemParserDesc =ReopenParser (MemParserDesc);
  //4. 解析uefiplat.cfg 中的 [MemoryMap] 区域EnumCommaDelimSectionItems (MemParserDesc, (UINT8*)"MemoryMap",ProcessMemoryMapTokens)
GetCfgMemMapBounds();

  //UpdateSystemMemoryRegions();
MemParserDesc =ReopenParser (MemParserDesc);
  //5. 解析uefiplat.cfg 中çš��?[RegisterMap] 区域，å†EnumCommaDelimSectionItems (MemParserDesc, (UINT8*)"RegisterMap",ProcessMemoryMapTokens)
MemParserDesc =ReopenParser (MemParserDesc);

  /* Reset for RAM load */
ConfigTable =NULL;
ConfigTableEntryCount = 0;
// 6. 解析uefiplat.cfg 中的 [ConfigParameters] 区域// 内容保存在 ConfigTable 中，ConfigTableEntryCount表示其内容的数量EnumKeyValues (MemParserDesc, (UINT8*)"ConfigParameters",ParseConfigParameters)
MemParserDesc =ReopenParser (MemParserDesc);

  //7. 解析uefiplat.cfg 中的 [ChipIDConfig] 区域EnumCommaDelimSectionItems (MemParserDesc, (UINT8*)"ChipIDConfig",ParseChipIDConfigParameters) < 0

CloseParser(MemParserDesc);

  returnEFI_SUCCESS;

ErrorExit:
DEBUG ((EFI_D_ERROR, "Failed LoadAndParsePlatformCfg\\r\\n"));
CpuDeadLoop();
  returnStatus;
}

void UefiBootContinue(void* arg){
  //EFI_STATUS       Status = EFI_NOT_READY;
  UINT32          UefiStartTime= 0;
  UefiInfoBlkType* UefiInfoBlkPtr= NULL;
  UINTN           HobStackSize= 0;

  //...

  //创建Stack、CPU Hob信息
  BuildStackHob((EFI_PHYSICAL_ADDRESS)gStackBase, HobStackSize);
  BuildCpuHob(PcdGet8(PcdPrePiCpuMemorySize), PcdGet8(PcdPrePiCpuIoSize));

  /* Build HOB to pass up prodmode info for security applications */
  gProdmodeInfo= JTAGDebugDisableFusesBlown();
  BuildGuidDataHob(&gQcomProdmodeInfoGuid, &gProdmodeInfo, sizeof(BOOLEAN));

  //Display 早期初始化
  DisplayEarlyInfo();

  AddMemRegionHobs();

  /* Start perf here, after timer init, start at current tick value */
  //开启耗费的时间统计，用于计算性能
  InitPerf();

  /*Add performance hob for pei performance data*/
  AddPerformanceHob(gReset);

  //...

  /* Any non-critical initialization */
  TargetLateInit();

  /* Build memory allocation HOB for FV2 type
     Need to remove for decompressed image */
  BuildMemHobForFv(EFI_HOB_TYPE_FV2);

  SetUefiCrashCookie();

  SetUefiTargetReset();

  /* Load the DXE Core and transfer control to it */
  //åŠ è½½ä¸”å°†CPU交
  LoadDxeCoreFromFv(NULL, 0);

  /* DXE Core should always load and never return */
  ASSERT(FALSE);
  CpuDeadLoop();
}

// BOOT.XF.4.1/boot_images/QcomPkg/Drivers/BdsDxe/BdsEntry.c
VOID EFIAPI BdsEntry(IN EFI_BDS_ARCH_PROTOCOL  *This)
{
  // 1. 注册按键事件，按下按键后会回调到HotkeyEvent() 函数，最终调用到HotkeyCallback()函数中，解析其中的key scancode
  // Initialize hotkey service
  InitializeHotkeyService ();
  // 2. 平台BDS初始化，在其中会打印显示版本号，平台版本信息等等，调用LaunchDefaultBDSApps ()加载默认APP，调用SetupPlatformSecurity()初始化secureboot安全环境，挂载efisp分区，调用ReadAnyKey() 循环检测音量下键是否按下，从而更新对应的启动项
  PlatformBdsInit ();

  // 3. 初始化所有 DriverOptionList 上的 驱动协议。
  // Set up the device list based on EFI 1.1 variables
  // process Driver#### and Load the driver's in the driver option list
  BdsLibLoadDrivers (&DriverOptionList);

  // Check if we have the boot next option
  mBootNext = BdsLibGetVariableAndSize ( L"BootNext",&gEfiGlobalVariableGuid,&BootNextSize );

  // Setup some platform policy here
  PlatformBdsPolicyBehavior (&DriverOptionList, &BootOptionList, BdsProcessCapsules, BdsMemoryTest);
  // 4. 根据选择的启动方式，启动对应的的系统，  启动sheLl app
  // BDS select the boot device to load OS
  BdsBootDeviceSelect ();

  // Only assert here since this is the right behavior, we should never
  // return back to DxeCore.
  ASSERT (FALSE);
  return ;
}

EFIAPILaunchDefaultBDSApps (VOID){

EFI_STATUSStatus =EFI_SUCCESS;
CHAR8DefaultApp[DEF_APP_STR_LEN];
UINTNSize =DEF_APP_STR_LEN;
CHAR8FileinFV[64] = {0};
  //1.解析 uefiplat.cfg中的DefaultChargerApp，字符串保存在DefaultApp数组中Status =GetConfigString ("DefaultChargerApp",DefaultApp, &Size);
AsciiStrCpy (FileinFV,FILE_IN_FV_PREPEND);
AsciiStrCat (FileinFV,DefaultApp);

  if (Status ==EFI_SUCCESS)
  {
    //2. 加载QcomChargerApp 应用程序，传参gMainFvGuid 和 “DefaultChargerApp”Status =LoadImageFromFV (FileinFV,NULL );
    if (EFI_ERROR(Status))
DEBUG((EFI_D_ERROR, "Failed to launch default charger app, status: %r\\n",Status));
  }

Size =DEF_APP_STR_LEN;
  // 3. 解析 uefiplat.cfg中的DefaultBDSBootApp，字符串保存在DefaultApp数组中。Status =GetConfigString ("DefaultBDSBootApp",DefaultApp, &Size);
  if (Status ==EFI_SUCCESS)
  {
DisplayPOSTTime ();
    //4. 加载DefaultBDSBootApp 应用程序，加载后不再返回LaunchAppFromGuidedFv(&gEfiAblFvNameGuid,DefaultApp,NULL);
    //If we return from above function, considered a failure
ConfirmShutdownOnFailure();
  }
  else
  {
DEBUG ((EFI_D_INFO, "[QcomBds] No default boot app specified\\n"));
  }

  returnStatus;
}