Add function to fetch platform specific reset reason register values

hal/reset_reason_api.h

@@ -20,6 +20,8 @@
 
 #if DEVICE_RESET_REASON
 
+#include <stdint.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -39,8 +41,7 @@ typedef enum {
   RESET_REASON_UNKNOWN         /**< Unknown or unreadable reset reason **/
 } reset_reason_t;
 
-/**
- * Fetch the reset reason for the last system reset
+/** Fetch the reset reason for the last system reset
  *
  * Note: Some platforms contain reset reason registers that persist through
  * system resets. If the registers haven't been cleared before calling this
@@ -51,8 +52,16 @@ typedef enum {
  */
 reset_reason_t hal_reset_reason_get(void);
 
-/**
- * Clear the reset reason from registers
+
+/** Fetch the raw platform specific reset reason register value
+ *
+ * @return value containing the reset reason register for the given platform.
+ *         If the platform contains reset reasons across multiple registers they
+ *         will be concatenated here.
+ */
+uint32_t hal_reset_reason_get_raw(void);
+
+/** Clear the reset reason from registers
  *
  * Reset the value of the reset status registers, the reset reason will persist
  * between system resets on certain platforms so the registers should be cleared

platform/mbed_reset_reason.cpp

@@ -26,10 +26,20 @@ reset_reason_t mbed_reset_reason_get(void)
   // this function resets it.
   const static reset_reason_t reason = hal_reset_reason_get();
 
+  // Call get raw to cache the reset reason before clearing the registers.
+  hal_reset_reason_get_raw();
   hal_reset_reason_clear();
 
   return reason;
 }
+
+uint32_t mbed_reset_reason_get_raw(void)
+{
+  const static uint32_t reason = hal_reset_reason_get_raw();
+
+  return reason;
+}
+
 } // namespace mbed
 
 #endif // DEVICE_RESET_REASON

platform/mbed_reset_reason.h

@@ -22,6 +22,8 @@
 
 #include "reset_reason_api.h"
 
+#include <stdint.h>
+
 namespace mbed {
 /** \addtogroup platform */
 /** @{*/
@@ -44,6 +46,23 @@ namespace mbed {
  */
 reset_reason_t mbed_reset_reason_get(void);
 
+
+/** Get the platform specific reason code for the last system reset.
+ *
+ * Platform specific reasons that are not covered by the reset_reason_t enum
+ * will cause the mbed_reset_reason_get function to return RESET_REASON_PLATFORM
+ * In order to get the actual reason the register value must be fetched directly
+ * using this function and interpreted in a platform specific manner.
+ *
+ * Example:
+ * @code
+ * if (mbed_reset_reason_get() == RESET_REASON_PLATFORM) {
+ *   const uint32_t platform_reason = mbed_reset_reason_get_raw();
+ * }
+ * @endcode
+ */
+uint32_t mbed_reset_reason_get_raw(void);
+
 /**@}*/
 /**@}*/
 

targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/TARGET_MCU_K64F/reset_reason.c

@@ -74,6 +74,13 @@ reset_reason_t hal_reset_reason_get(void)
     return RESET_REASON_UNKNOWN;
 }
 
+
+uint32_t hal_reset_reason_get_raw(void)
+{
+    return (RCM_GetPreviousResetSources(RCM) & kRCM_SourceAll);
+}
+
+
 void hal_reset_reason_clear(void)
 {
 #if (defined(FSL_FEATURE_RCM_HAS_SSRS) && FSL_FEATURE_RCM_HAS_SSRS)

targets/TARGET_STM/reset_reason.c

@@ -51,6 +51,13 @@ reset_reason_t hal_reset_reason_get(void)
     return RESET_REASON_UNKNOWN;
 }
 
+
+uint32_t hal_reset_reason_get_raw(void)
+{
+    return RCC->CSR;
+}
+
+
 void hal_reset_reason_clear(void)
 {
     __HAL_RCC_CLEAR_RESET_FLAGS();