boards: arm: stm32u585 disco with external memory region for XiP

Declare a sub-region of the whole ext_memory with attributes
ATTR_MPU_IO so that XiP becomes possible on this external
octo- NOR flash. Use the STM32CubeProgrammer runner
with the external loader for flashing.

Signed-off-by: Francois Ramu <[email protected]>

Author: FRASTM

boards/st/b_u585i_iot02a/b_u585i_iot02a.dts

@@ -6,6 +6,8 @@
 
 /dts-v1/;
 #include "b_u585i_iot02a-common.dtsi"
+#include <zephyr/dt-bindings/memory-attr/memory-attr.h>
+#include <zephyr/dt-bindings/memory-attr/memory-attr-arm.h>
 
 / {
 	model = "STMicroelectronics B-U585I-IOT02A discovery kit";
@@ -25,6 +27,14 @@
 		led1 = &red_led_1;
 		sw0 = &user_button;
 	};
+
+	octo_nor: memory@70000000 {
+		compatible = "zephyr,memory-region";
+		reg = <0x70000000 DT_SIZE_M(64)>;
+		zephyr,memory-region = "EXTMEM";
+		/* The ATTR_MPU_EXTMEM attribut causing a MPU FAULT */
+		zephyr,memory-attr = <( DT_MEM_ARM(ATTR_MPU_IO) )>;
+	};
 };
 
 &flash0 {

boards/st/b_u585i_iot02a/board.cmake

@@ -12,8 +12,13 @@ if(CONFIG_BUILD_WITH_TFM)
   endif()
 endif()
 
-board_runner_args(stm32cubeprogrammer "--erase" "--port=swd" "--reset-mode=hw")
+if(CONFIG_STM32_MEMMAP)
 board_runner_args(stm32cubeprogrammer "--port=swd" "--reset-mode=hw")
+board_runner_args(stm32cubeprogrammer "--hex-file=${ZEPHYR_BASE}/build/zephyr/zephyr.hex")
+board_runner_args(stm32cubeprogrammer "--extload=MX25LM51245G_STM32U585I-IOT02A.stldr")
+else()
+board_runner_args(stm32cubeprogrammer "--erase" "--port=swd" "--reset-mode=hw")
+endif()
 
 board_runner_args(openocd "--tcl-port=6666")
 board_runner_args(openocd --cmd-pre-init "gdb_report_data_abort enable")