AP_Bootloader: added flash size limiting on old CPUs

Tools/AP_Bootloader/AP_Bootloader.cpp

@@ -48,6 +48,9 @@ int main(void)
     board_info.board_type = APJ_BOARD_ID;
     board_info.board_rev = 0;
     board_info.fw_size = (BOARD_FLASH_SIZE - FLASH_BOOTLOADER_LOAD_KB)*1024;
+    if (BOARD_FLASH_SIZE > 1024 && check_limit_flash_1M()) {
+        board_info.fw_size = (1024 - FLASH_BOOTLOADER_LOAD_KB)*1024;        
+    }
 
     flash_init();
 

Tools/AP_Bootloader/bl_protocol.cpp

@@ -740,6 +740,9 @@ bootloader(unsigned timeout)
             continue;
         }
 
+        // we got a good command on this port, lock to the port
+        lock_bl_port();
+        
         // we got a command worth syncing, so kill the timeout because
         // we are probably talking to the uploader
         timeout = 0;

Tools/AP_Bootloader/mcu_f4.h

@@ -29,12 +29,12 @@ const mcu_des_t mcu_descriptions[] = {
 };
 
 const mcu_rev_t silicon_revs[] = {
-    {MCU_REV_STM32F4_REV_3, '3'}, /* Revision 3 */
+    {MCU_REV_STM32F4_REV_3, '3', false}, /* Revision 3 */
 
-    {MCU_REV_STM32F4_REV_A, 'A'}, /* Revision A */  // FIRST_BAD_SILICON_OFFSET (place good ones above this line and update the FIRST_BAD_SILICON_OFFSET accordingly)
-    {MCU_REV_STM32F4_REV_Z, 'Z'}, /* Revision Z */
-    {MCU_REV_STM32F4_REV_Y, 'Y'}, /* Revision Y */
-    {MCU_REV_STM32F4_REV_1, '1'}, /* Revision 1 */
+    {MCU_REV_STM32F4_REV_A, 'A', true}, /* Revision A */
+    {MCU_REV_STM32F4_REV_Z, 'Z', true}, /* Revision Z */
+    {MCU_REV_STM32F4_REV_Y, 'Y', true}, /* Revision Y */
+    {MCU_REV_STM32F4_REV_1, '1', true}, /* Revision 1 */
 };
 
 #endif // STM32F4

Tools/AP_Bootloader/support.cpp

@@ -159,6 +159,22 @@ uint32_t get_mcu_desc(uint32_t max, uint8_t *revstr)
     return  strp - revstr;
 }
 
+/*
+  see if we should limit flash to 1M on devices with older revisions
+ */
+bool check_limit_flash_1M(void)
+{
+    uint32_t idcode = (*(uint32_t *)DBGMCU_BASE);
+    uint16_t revid = ((idcode & REVID_MASK) >> 16);
+
+    for (int i = 0; i < ARRAY_SIZE_SIMPLE(silicon_revs); i++) {
+        if (silicon_revs[i].revid == revid) {
+            return silicon_revs[i].limit_flash_size_1M;
+        }
+    }
+    return false;
+}
+
 void led_on(unsigned led)
 {
 #ifdef HAL_GPIO_PIN_LED_BOOTLOADER
@@ -251,3 +267,7 @@ int strcmp(const char *s1, const char *s2)
     }
     return (*s1 - *s2);
 }
+
+void lock_bl_port(void)
+{
+}

Tools/AP_Bootloader/support.h

@@ -26,9 +26,11 @@ void flash_func_erase_sector(uint32_t sector);
 uint32_t flash_func_read_otp(uint32_t idx);
 uint32_t flash_func_read_sn(uint32_t idx);
 void flash_set_keep_unlocked(bool);
+void lock_bl_port(void);
 
 uint32_t get_mcu_id(void);
 uint32_t get_mcu_desc(uint32_t len, uint8_t *buf);
+bool check_limit_flash_1M(void);
 
 void led_on(unsigned led);
 void led_off(unsigned led);
@@ -49,4 +51,5 @@ typedef struct mcu_des_t {
 typedef struct mcu_rev_t {
     uint16_t revid;
     char  rev;
+    bool limit_flash_size_1M;
 } mcu_rev_t;