Feat: Add watchdog disable

example/stub_main.c

@@ -15,6 +15,7 @@
 #include <esp-stub-lib/mem_utils.h>
 #include <esp-stub-lib/security.h>
 #include <esp-stub-lib/uart.h>
+#include <esp-stub-lib/usb_serial_jtag.h>
 
 #include "stub_main.h"
 
@@ -63,6 +64,18 @@ static void example_security(void)
     }
 }
 
+static void __attribute__((unused)) test_usb_serial_jtag_disable_watchdogs(void)
+{
+    stub_lib_usb_serial_jtag_disable_watchdogs();
+    (void)stub_lib_usb_serial_jtag_is_active();
+    (void)stub_lib_usb_serial_jtag_rominit_intr_attach(17, NULL, 0);
+    (void)stub_lib_usb_serial_jtag_clear_intr_flags();
+    (void)stub_lib_usb_serial_jtag_is_data_available();
+    (void)stub_lib_usb_serial_jtag_read_rxfifo_byte();
+    (void)stub_lib_usb_serial_jtag_tx_one_char('A');
+    (void)stub_lib_usb_serial_jtag_tx_flush();
+}
+
 static int __attribute__((unused)) handle_test_uart(void)
 {
     void *uart_rx_interrupt_handler = NULL;

include/esp-stub-lib/usb_serial_jtag.h

@@ -16,6 +16,15 @@ extern "C"
 
 #define USB_SERIAL_JTAG_OUT_RECV_PKT_INT_ENA    (0x1 << 2)
 
+/**
+ * @brief Disable watchdogs for USB-Serial/JTAG
+ *
+ * This function disables the watchdogs for USB-Serial/JTAG to prevent the device from resetting.
+ * By default watchdog is disabled after chip reset, but second stage bootloader may enable it again,
+ * and if application does not disable it, it will reset the device, because USB-Serial/JTAG does only software reset.
+ */
+void stub_lib_usb_serial_jtag_disable_watchdogs(void);
+
 /**
  * @brief Check if USB-Serial/JTAG is currently being used for communication
  *

src/target/base/include/target/usb_serial_jtag.h

@@ -10,11 +10,13 @@
 #include <stdbool.h>
 
 /**
- * @brief Check if USB-Serial/JTAG is supported on this chip
+ * @brief Disable watchdogs for USB-Serial/JTAG
  *
- * @return true if USB-Serial/JTAG is supported, false otherwise
+ * This function disables the watchdogs for USB-Serial/JTAG to prevent the device from resetting.
+ * By default watchdog is disabled after chip reset, but second stage bootloader may enable it again,
+ * and if application does not disable it, it will reset the device, because USB-Serial/JTAG does only software reset.
  */
-bool stub_target_usb_serial_jtag_is_supported(void);
+void stub_target_usb_serial_jtag_disable_watchdogs(void);
 
 /**
  * @brief Attach interrupt handler to USB-Serial/JTAG and configure interrupts

src/target/common/CMakeLists.txt

@@ -3,7 +3,6 @@ set(common_srcs
     src/mem_utils.c
     src/security.c
     src/uart.c
-    src/usb_serial_jtag.c
 )
 
 add_library(${ESP_COMMON_LIB} STATIC ${common_srcs})

src/target/esp32c3/src/usb_serial_jtag.c

@@ -10,16 +10,28 @@
 #include <target/usb_serial_jtag.h>
 #include <soc/usb_serial_jtag_reg.h>
 #include <soc/interrupt_core0_reg.h>
+#include <soc/rtc_cntl_reg.h>
 #include <soc_utils.h>
 
 // External ROM functions
 extern void esp_rom_isr_attach(int int_num, void *handler, void *arg);
 extern void esp_rom_isr_unmask(int int_num);
 extern void esprv_intc_int_set_priority(int int_num, int priority);
 
-bool stub_target_usb_serial_jtag_is_supported(void)
+#define RTC_CNTL_WDT_KEY 0x50D83AA1
+#define RTC_CNTL_SWD_KEY 0x8F1D312A
+
+void stub_target_usb_serial_jtag_disable_watchdogs(void)
 {
-    return true;
+    // Disable RWDT (RTC Watchdog)
+    WRITE_PERI_REG(RTC_CNTL_WDTWPROTECT_REG, RTC_CNTL_WDT_WKEY);
+    WRITE_PERI_REG(RTC_CNTL_WDTCONFIG0_REG, 0x0);
+    WRITE_PERI_REG(RTC_CNTL_WDTWPROTECT_REG, 0x0);
+
+    // Configure SWD (Super Watchdog) to autofeed
+    WRITE_PERI_REG(RTC_CNTL_SWD_WPROTECT_REG, RTC_CNTL_SWD_WKEY);
+    SET_PERI_REG_MASK(RTC_CNTL_SWD_CONF_REG, RTC_CNTL_SWD_AUTO_FEED_EN);
+    WRITE_PERI_REG(RTC_CNTL_SWD_WPROTECT_REG, 0x0);
 }
 
 void stub_target_usb_serial_jtag_rominit_intr_attach(int intr_num, void *handler, uint32_t flags)