stm32/mboot: Allow mboot to be placed at any location in flash.

A board can now define MBOOT_TEXT0_ADDR to place mboot at a location other
than 0x08000000.  This can be useful if, for example, there is already a
different bootloader on the device.

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

ports/stm32/Makefile

@@ -27,6 +27,10 @@ MICROPY_ROM_TEXT_COMPRESSION ?= 1
 # File containing description of content to be frozen into firmware.
 FROZEN_MANIFEST ?= boards/manifest.py
 
+# Location of mboot (or other bootloader) if the device has one.
+# Used by machine.bootloader().
+MBOOT_TEXT0_ADDR ?= 0x08000000
+
 # include py core make definitions
 include $(TOP)/py/py.mk
 
@@ -101,6 +105,7 @@ CFLAGS += $(CFLAGS_MCU_$(MCU_SERIES))
 CFLAGS += $(COPT)
 CFLAGS += -I$(BOARD_DIR)
 CFLAGS += -DSTM32_HAL_H='<stm32$(MCU_SERIES)xx_hal.h>'
+CFLAGS += -DMBOOT_VTOR=$(MBOOT_TEXT0_ADDR)
 CFLAGS += -DMICROPY_HW_VTOR=$(TEXT0_ADDR)
 
 # Configure for nan-boxing object model if requested

ports/stm32/mboot/Makefile

@@ -29,6 +29,9 @@ BUILDING_MBOOT = 1
 include ../../../py/mkenv.mk
 include $(BOARD_DIR)/mpconfigboard.mk
 
+# A board can set MBOOT_TEXT0_ADDR to a custom location where mboot should reside.
+MBOOT_TEXT0_ADDR ?= 0x08000000
+
 MCU_SERIES_UPPER = $(shell echo $(MCU_SERIES) | tr '[:lower:]' '[:upper:]')
 CMSIS_MCU_LOWER = $(shell echo $(CMSIS_MCU) | tr '[:upper:]' '[:lower:]')
 
@@ -77,6 +80,7 @@ CFLAGS += $(COPT)
 CFLAGS += -I$(BOARD_DIR)
 CFLAGS += -DSTM32_HAL_H='<stm32$(MCU_SERIES)xx_hal.h>'
 CFLAGS += -DBOARD_$(BOARD)
+CFLAGS += -DMBOOT_VTOR=$(MBOOT_TEXT0_ADDR)
 CFLAGS += -DAPPLICATION_ADDR=$(TEXT0_ADDR)
 CFLAGS += -DFFCONF_H=\"ports/stm32/mboot/ffconf.h\"
 CFLAGS += -DLFS1_NO_MALLOC -DLFS1_NO_DEBUG -DLFS1_NO_WARN -DLFS1_NO_ERROR -DLFS1_NO_ASSERT
@@ -181,20 +185,18 @@ $(TOP)/lib/stm32lib/README.md:
 
 .PHONY: deploy deploy-stlink
 
-FLASH_ADDR = 0x08000000
-
 deploy: $(BUILD)/firmware.dfu
 	$(ECHO) "Writing $< to the board"
 	$(Q)$(PYTHON) $(PYDFU) -u $<
 
 deploy-stlink: $(BUILD)/firmware.dfu
 	$(ECHO) "Writing $< to the board via ST-LINK"
-	$(Q)$(STFLASH) write $(BUILD)/firmware.bin $(FLASH_ADDR)
+	$(Q)$(STFLASH) write $(BUILD)/firmware.bin $(MBOOT_TEXT0_ADDR)
 
 $(BUILD)/firmware.dfu: $(BUILD)/firmware.elf
 	$(ECHO) "Create $@"
 	$(Q)$(OBJCOPY) -O binary -j .isr_vector -j .text -j .data $^ $(BUILD)/firmware.bin
-	$(Q)$(PYTHON) $(DFU) -b $(FLASH_ADDR):$(BUILD)/firmware.bin $@
+	$(Q)$(PYTHON) $(DFU) -b $(MBOOT_TEXT0_ADDR):$(BUILD)/firmware.bin $@
 
 $(BUILD)/firmware.hex: $(BUILD)/firmware.elf
 	$(ECHO) "Create $@"

ports/stm32/mboot/main.c

@@ -1358,7 +1358,7 @@ void stm32_main(int initial_r0) {
     #endif
 
     // Make sure IRQ vector table points to flash where this bootloader lives.
-    SCB->VTOR = FLASH_BASE;
+    SCB->VTOR = MBOOT_VTOR;
 
     // Enable 8-byte stack alignment for IRQ handlers, in accord with EABI
     SCB->CCR |= SCB_CCR_STKALIGN_Msk;

ports/stm32/modmachine.c

@@ -270,16 +270,16 @@ STATIC NORETURN mp_obj_t machine_bootloader(size_t n_args, const mp_obj_t *args)
     #if MICROPY_HW_USES_BOOTLOADER
     if (n_args == 0 || !mp_obj_is_true(args[0])) {
         // By default, with no args given, we enter the custom bootloader (mboot)
-        powerctrl_enter_bootloader(0x70ad0000, 0x08000000);
+        powerctrl_enter_bootloader(0x70ad0000, MBOOT_VTOR);
     }
 
     if (n_args == 1 && mp_obj_is_str_or_bytes(args[0])) {
         // With a string/bytes given, pass its data to the custom bootloader
         size_t len;
         const char *data = mp_obj_str_get_data(args[0], &len);
-        void *mboot_region = (void *)*((volatile uint32_t *)0x08000000);
+        void *mboot_region = (void *)*((volatile uint32_t *)MBOOT_VTOR);
         memmove(mboot_region, data, len);
-        powerctrl_enter_bootloader(0x70ad0080, 0x08000000);
+        powerctrl_enter_bootloader(0x70ad0080, MBOOT_VTOR);
     }
     #endif