Merge branch 'feature/disable_jtag_io_when_boot_v3.1' into 'release/v3.1'

feat(bootloader): add option to disable JTAG I/O when boot (backport v3.1)

See merge request sdk/ESP8266_RTOS_SDK!1421

components/bootloader/Kconfig.projbuild

@@ -10,6 +10,15 @@ config BOOTLOADER_INIT_SPI_FLASH
         If your system bootloader is based on v3.0, the option must not be enable, because the v3.0 bootloader don't support
         this function.
 
+config BOOTLOADER_DISABLE_JTAG_IO
+    bool "Bootloader disable JTAG I/O"
+    default n 
+    help
+        Enable this option, when SoC brings up and bootloader initializes hardware, it will
+        disable JTAG's I/O and set these GPIOs to be normal I/O with inputting mode.
+
+        If users use JTAG to help develop, please disable this option.
+
 choice LOG_BOOTLOADER_LEVEL
    bool "Bootloader log verbosity"
    default LOG_BOOTLOADER_LEVEL_INFO

components/bootloader_support/src/bootloader_init.c

@@ -613,6 +613,17 @@ esp_err_t bootloader_init()
 
 static esp_err_t bootloader_main()
 {
+#ifdef CONFIG_BOOTLOADER_DISABLE_JTAG_IO
+    /* Set GPIO 12-15 to be normal GPIO  */
+    PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTDI_U, FUNC_GPIO12);
+    PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTCK_U, FUNC_GPIO13);
+    PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTMS_U, FUNC_GPIO14);
+    PIN_FUNC_SELECT(PERIPHS_IO_MUX_MTDO_U, FUNC_GPIO15);
+
+    /* Set GPIO 12-15 to be input mode  */
+    GPIO_REG_WRITE(GPIO_ENABLE_W1TC_ADDRESS, BIT12 | BIT13 | BIT14 | BIT15);
+#endif
+
     uart_console_configure();
 
     esp_image_header_t fhdr;

docs/en/general-notes/index.rst

@@ -27,3 +27,14 @@ You need to disable the sniffer/promiscuous mode at first, then read/write/erase
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 ESP8285 or ESP8266 + 1MB flash can use "Copy OTA Mode" for OTA, more details are in the `examples/system/ota <https://github.com/espressif/ESP8266_RTOS_SDK/tree/master/examples/system/ota/>`_.
+
+4. JTAG I/O
+^^^^^^^^^^^
+
+In some cases, if enable JTAG I/O (default options), it will cost some more current so that the hardware will cost more power.
+So if users don't use Jtag or these GPIOs directly and want to save more power, please enable this option in the menuconfig:
+
+::
+
+    "Bootloader config  --->
+        [ ] Bootloader disable JTAG I/O"