fix(rtc): fixed bbpll not calibrated from bootloader issue

components/esp_system/Kconfig

@@ -564,6 +564,15 @@ menu "ESP System Settings"
             This config allows to trigger a panic interrupt when Stack Pointer register goes out of allocated stack
             memory bounds.
 
+    config ESP_SYSTEM_BBPLL_RECALIB
+        bool "Re-calibration BBPLL at startup"
+        depends on IDF_TARGET_ESP32C2 || IDF_TARGET_ESP32S3 || IDF_TARGET_ESP32C6 || IDF_TARGET_ESP32H2
+        default y
+        help
+            This configuration helps to address an BBPLL inaccurate issue when boot from certain bootloader version,
+            which may increase about the boot-up time by about 200 us. Disable this when your bootloader is built with
+            ESP-IDF version v5.2 and above.
+
 endmenu  # ESP System Settings
 
 menu "IPC (Inter-Processor Call)"

components/esp_system/port/cpu_start.c

@@ -544,7 +544,14 @@ void IRAM_ATTR call_start_cpu0(void)
      * In this stage, we re-configure the Flash (and MSPI) to required configuration
      */
     spi_flash_init_chip_state();
+
+    // In earlier version of ESP-IDF, the PLL provided by bootloader is not stable enough.
+    // Do calibration again here so that we can use better clock for the timing tuning.
+#if CONFIG_ESP_SYSTEM_BBPLL_RECALIB
+    rtc_clk_recalib_bbpll();
+#endif
 #if SOC_MEMSPI_SRC_FREQ_120M
+    // This function needs to be called when PLL is enabled
     mspi_timing_flash_tuning();
 #endif