AP_HAL: added run_debug_shell() hal.util method

libraries/AP_HAL/Util.h

@@ -20,6 +20,11 @@ public:
     virtual int vsnprintf_P(char* str, size_t size,
             const prog_char_t *format, va_list ap) = 0;
 
+    // run a debug shall on the given stream if possible. This is used
+    // to support dropping into a debug shell to run firmware upgrade
+    // commands
+    virtual bool run_debug_shell(AP_HAL::BetterStream *stream) = 0;
+
 };
 
 #endif // __AP_HAL_UTIL_H__

libraries/AP_HAL_AVR/Util.h

@@ -12,6 +12,7 @@ public:
     int vsnprintf(char* str, size_t size, const char *format, va_list ap);
     int vsnprintf_P(char* str, size_t size, const prog_char_t *format,
             va_list ap);
+    bool run_debug_shell(AP_HAL::BetterStream *stream) { return false; }
 };
 
 #endif // __AP_HAL_AVR_UTIL_H__

libraries/AP_HAL_AVR_SITL/Util.h

@@ -12,6 +12,7 @@ public:
     int vsnprintf(char* str, size_t size, const char *format, va_list ap);
     int vsnprintf_P(char* str, size_t size, const prog_char_t *format,
             va_list ap);
+    bool run_debug_shell(AP_HAL::BetterStream *stream) { return false; }
 };
 
 #endif // __AP_HAL_SITL_UTIL_H__

libraries/AP_HAL_Empty/Util.h

@@ -12,6 +12,7 @@ public:
     int vsnprintf(char* str, size_t size, const char *format, va_list ap);
     int vsnprintf_P(char* str, size_t size, const prog_char_t *format,
             va_list ap);
+    bool run_debug_shell(AP_HAL::BetterStream *stream) { return false; }
 };
 
 #endif // __AP_HAL_EMPTY_UTIL_H__

libraries/AP_HAL_SMACCM/Util.h

@@ -12,6 +12,7 @@ public:
     int vsnprintf(char* str, size_t size, const char *format, va_list ap);
     int vsnprintf_P(char* str, size_t size, const prog_char_t *format,
             va_list ap);
+    bool run_debug_shell(AP_HAL::BetterStream *stream) { return false; }
 };
 
 #endif // __AP_HAL_SMACCM_UTIL_H__