stm32/boards/LEGO_HUB_NO6: Implement robust filesystem-load updates.

Signed-off-by: Damien George <damien@micropython.org>

ports/stm32/boards/LEGO_HUB_NO6/board_init.c

@@ -3,7 +3,7 @@
  *
  * The MIT License (MIT)
  *
- * Copyright (c) 2021 Damien P. George
+ * Copyright (c) 2021-2022 Damien P. George
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -75,6 +75,7 @@ void board_init(void) {
 
 #if BUILDING_MBOOT
 
+#include "drivers/memory/spiflash.h"
 #include "mboot/mboot.h"
 #include "boardctrl.h"
 #include "adc.h"
@@ -88,6 +89,14 @@ void board_init(void) {
 #define PATTERN_N (0x01296ad2)
 #define PATTERN_S (0x0064104c)
 
+// Location and value for the SPI flash update key.  If this key exists at the defined
+// location then mboot will attempt to do a filesystem-load update of the main firmware.
+// This makes the update robust to power failures: if the update does not complete then
+// it will be restarted the next time it powers up.  Only when it fully completes will
+// this key be erased, and then the application can run.
+#define SPIFLASH_UPDATE_KEY_ADDR (1020 * 1024)
+#define SPIFLASH_UPDATE_KEY_VALUE (0x12345678)
+
 static void board_led_pattern(int reset_mode, uint16_t brightness) {
     static const uint32_t pixels[] = {
         0,
@@ -162,9 +171,36 @@ int board_mboot_get_reset_mode(uint32_t *initial_r0) {
             mp_hal_delay_ms(50);
         }
         mp_hal_delay_ms(300);
+    } else {
+        // Button not pressed, check flash for update key and start an update if the key exists.
+
+        // Initialise the external SPI flash.
+        MBOOT_SPIFLASH_SPIFLASH->config = MBOOT_SPIFLASH_CONFIG;
+        mp_spiflash_init(MBOOT_SPIFLASH_SPIFLASH);
+
+        // Read in the key.
+        uint32_t buf;
+        mp_spiflash_read(MBOOT_SPIFLASH_SPIFLASH, SPIFLASH_UPDATE_KEY_ADDR, 4, (uint8_t *)&buf);
+
+        if (buf == SPIFLASH_UPDATE_KEY_VALUE) {
+            // The key has the correct value, so read in the FS-load elements and enter the bootloader.
+            mp_spiflash_read(MBOOT_SPIFLASH_SPIFLASH, SPIFLASH_UPDATE_KEY_ADDR + 4, ELEM_DATA_SIZE, ELEM_DATA_START);
+            *initial_r0 = MBOOT_INITIAL_R0_KEY_FSLOAD;
+            reset_mode = BOARDCTRL_RESET_MODE_BOOTLOADER;
+        }
     }
     board_led_pattern(0, 0);
     return reset_mode;
 }
 
+void board_mboot_state_change(int state, uint32_t arg) {
+    if (state == MBOOT_STATE_FSLOAD_END) {
+        // The FS-load update completed (either with success or failure), so erase the
+        // update key and write the result of the FS-load operation into flash.
+        mp_spiflash_erase_block(MBOOT_SPIFLASH_SPIFLASH, SPIFLASH_UPDATE_KEY_ADDR);
+        mp_spiflash_write(MBOOT_SPIFLASH_SPIFLASH, SPIFLASH_UPDATE_KEY_ADDR + 4, 4, (const uint8_t *)&arg);
+    }
+    mboot_state_change_default(state, arg);
+}
+
 #endif

ports/stm32/boards/LEGO_HUB_NO6/mpconfigboard.h

@@ -153,6 +153,7 @@
 #define MBOOT_BOARD_EARLY_INIT(initial_r0)       board_init()
 #define MBOOT_BOARD_CLEANUP                      board_mboot_cleanup
 #define MBOOT_BOARD_GET_RESET_MODE               board_mboot_get_reset_mode
+#define MBOOT_BOARD_STATE_CHANGE                 board_mboot_state_change
 
 /******************************************************************************/
 // Function declarations
@@ -167,4 +168,5 @@ void board_mboot_cleanup(int reset_mode);
 void board_mboot_led_init(void);
 void board_mboot_led_state(int led, int state);
 int board_mboot_get_reset_mode(uint32_t *initial_r0);
+void board_mboot_state_change(int state, uint32_t arg);
 void *btstack_chipset_cc256x_instance(void);