Import of the watch repository from Pebble

src/fw/drivers/stm32f2/watchdog.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "drivers/watchdog.h"
+
+#include "util/bitset.h"
+#include "system/logging.h"
+
+#define STM32F2_COMPATIBLE
+#define STM32F4_COMPATIBLE
+#define STM32F7_COMPATIBLE
+#include <mcu.h>
+
+#include <inttypes.h>
+
+void watchdog_init(void) {
+  IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
+
+  IWDG_SetPrescaler(IWDG_Prescaler_64); // ~8 seconds
+  IWDG_SetReload(0xfff);
+
+  IWDG_WriteAccessCmd(IWDG_WriteAccess_Disable);
+
+  DBGMCU_APB1PeriphConfig(DBGMCU_IWDG_STOP, ENABLE);
+}
+
+void watchdog_start(void) {
+  IWDG_Enable();
+  watchdog_feed();
+}
+
+// This behaves differently from the bootloader and the firmware.
+void watchdog_feed(void) {
+  IWDG_ReloadCounter();
+}
+
+bool watchdog_check_reset_flag(void) {
+  return RCC_GetFlagStatus(RCC_FLAG_IWDGRST) != RESET;
+}
+
+McuRebootReason watchdog_clear_reset_flag(void) {
+  McuRebootReason mcu_reboot_reason = {
+    .brown_out_reset = (RCC_GetFlagStatus(RCC_FLAG_BORRST) != RESET),
+    .pin_reset = (RCC_GetFlagStatus(RCC_FLAG_PINRST) != RESET),
+    .power_on_reset = (RCC_GetFlagStatus(RCC_FLAG_PORRST) != RESET),
+    .software_reset = (RCC_GetFlagStatus(RCC_FLAG_SFTRST) != RESET),
+    .independent_watchdog_reset = (RCC_GetFlagStatus(RCC_FLAG_IWDGRST) != RESET),
+    .window_watchdog_reset = (RCC_GetFlagStatus(RCC_FLAG_WWDGRST) != RESET),
+    .low_power_manager_reset = (RCC_GetFlagStatus(RCC_FLAG_LPWRRST) != RESET)
+  };
+
+  RCC_ClearFlag();
+
+  return mcu_reboot_reason;
+}