AP_BoardConfig: add options for write protecting bootloader and main flash

add option to completely remove protection on flash banks

libraries/AP_BoardConfig/AP_BoardConfig.cpp

@@ -275,7 +275,7 @@ const AP_Param::GroupInfo AP_BoardConfig::var_info[] = {
     // @Param: OPTIONS
     // @DisplayName: Board options
     // @Description: Board specific option flags
-    // @Bitmask: 0:Enable hardware watchdog, 1:Disable MAVftp, 2:Enable set of internal parameters, 3:Enable Debug Pins
+    // @Bitmask: 0:Enable hardware watchdog, 1:Disable MAVftp, 2:Enable set of internal parameters, 3:Enable Debug Pins, 4:Unlock flash on reboot, 5:Write protect firmware flash on reboot, 6:Write protect bootloader flash on reboot
     // @User: Advanced
     AP_GROUPINFO("OPTIONS", 19, AP_BoardConfig, _options, HAL_BRD_OPTIONS_DEFAULT),
 

libraries/AP_BoardConfig/AP_BoardConfig.h

@@ -172,6 +172,9 @@ public:
         DISABLE_FTP = (1<<1),
         ALLOW_SET_INTERNAL_PARM = (1<<2),
         BOARD_OPTION_DEBUG_ENABLE = (1<<3),
+        UNLOCK_FLASH = (1<<4),
+        WRITE_PROTECT_FLASH = (1<<5),
+        WRITE_PROTECT_BOOTLOADER = (1<<6),
     };
 
     // return true if ftp is disabled
@@ -184,6 +187,21 @@ public:
         return _singleton?(_singleton->_options & BOARD_OPTION_WATCHDOG)!=0:HAL_WATCHDOG_ENABLED_DEFAULT;
     }
 
+    // return true if flash should be unlocked
+    static bool unlock_flash(void) {
+        return _singleton && (_singleton->_options & UNLOCK_FLASH) != 0;
+    }
+
+    // return true if flash should be write protected
+    static bool protect_flash(void) {
+        return _singleton && (_singleton->_options & WRITE_PROTECT_FLASH) != 0;
+    }
+
+    // return true if bootloader should be write protected
+    static bool protect_bootloader(void) {
+        return _singleton && (_singleton->_options & WRITE_PROTECT_BOOTLOADER) != 0;
+    }
+
     // return true if we allow setting of internal parameters (for developers)
     static bool allow_set_internal_parameters(void) {
         return _singleton?(_singleton->_options & ALLOW_SET_INTERNAL_PARM)!=0:false;