MTK平台preloader启动过程中UART初始化过程

1、一切从这里开始alps/bootable/bootloader/preloader/platform/XXXX/src/init/init.s
2、由init.s跳转至alps/bootable/bootloader/preloader/platform/XXXX/src/core/main.c
void main(void)
       static void bldr_pre_process(void)
                  void platform_pre_init(void)
                                //set UART1 GPIO to mode1, AP
                                mt_gpio_init_post(0);

                                /* init uart baudrate when pll on */
                                     mtk_uart_init(UART_SRC_CLK_FRQ, CFG_LOG_BAUDRATE);
                                 BOOTING_TIME_PROFILING_LOG("uart");

                                 /* init pmic i2c interface and pmic */
                                  /* no need in MT6572*/
                                  //i2c_ret = i2c_v1_init();
                                  //retry 3 times for pmic wrapper init
                                  pwrap_init_preloader();