boards: stm32h7s78_dk: Introduce App in Ext Flash variant #97992

erwango · 2025-10-21T11:50:43Z

Based on #97037

Similarly to what is done for stm32h750_dk board in #97037, introduce a ext_flash_app board variant aiming at being chainloaded by MCUBoot.
Requires mcuboot counter part (mcu-tools/mcuboot#2510) to allow MCUBoot to run on internal flash.

Doc not provided, waiting for #97037 to be merged.
@JarmouniA, in a fisrst step, I plan to redirect doc to stm32h750_dk to avoid redundant doc in each board.

github-actions · 2025-10-21T11:54:12Z

The following west manifest projects have changed revision in this Pull Request:

Name	Old Revision	New Revision	Diff
mcuboot	zephyrproject-rtos/mcuboot@`b192716` (`main`)	zephyrproject-rtos/mcuboot@`96576b3` (`upstream-sync`)	zephyrproject-rtos/[email protected]

✅ All manifest checks OK

Note: This message is automatically posted and updated by the Manifest GitHub Action.

maass-hamburg · 2025-10-23T08:43:37Z

boards/st/stm32h7s78_dk/stm32h7s78_dk-common.dtsi

+			compatible = "soc-nv-flash";
+			reg = <0x0 DT_SIZE_M(128)>;
+			write-block-size = <1>;
+			erase-block-size = <DT_SIZE_K(128)>;


Suggested change

erase-block-size = <DT_SIZE_K(128)>;

erase-block-size = <DT_SIZE_K(4)>;

lowest as possible, see #97037 (comment)

maass-hamburg · 2025-10-23T08:49:42Z

boards/st/stm32h7s78_dk/Kconfig.sysbuild

+choice MCUBOOT_MODE
+	default MCUBOOT_MODE_DIRECT_XIP
+endchoice


also use MCUBOOT_MODE_SWAP_USING_OFFSET like in #97037 ?

For some reason, MCUBOOT_MODE_SWAP_USING_OFFSET prevents building mcuboot image as it has an impact on following parameters (build/stm32h7s78_dk/stm32h7s7xx/ext_app_flash/mcubootCMakeCache.txt)

//Estimated MCUboot image trailer size mcuboot_image_footer_size:INTERNAL=32808 //Estimated MCUboot update image trailer size mcuboot_image_upgrade_footer_size:INTERNAL=32768

vs (SINGLE_APP_MODE & DIRECT_XIP)

//Estimated MCUboot image trailer size mcuboot_image_footer_size:INTERNAL=88 //Estimated MCUboot update image trailer size mcuboot_image_upgrade_footer_size:INTERNAL=48

As a consequence, this doesn't fit available RAM anymore.
Note that it is the same on stm32h750_dk because it can afford it:

Memory region Used Size Region Size %age Used FLASH: 34568 B 128 KB 26.37% RAM: 138304 B 512 KB 26.38%

but also trailers size are lower:

//Estimated MCUboot image trailer size mcuboot_image_footer_size:INTERNAL=16424 //Estimated MCUboot update image trailer size mcuboot_image_upgrade_footer_size:INTERNAL=16384

(Anyway, in any case, this wouldn't fit on stm32h7s78_dk which has only 128k of RAM)

I'll go for SINGLE_APP_MODE for now, but there is probably something to investigate here.

The ammount of sectors in slot0 and slot1 has a direct influence in mcuboot size, as it uses that for the size of an array. would propably work, if we make the flash driver respect the value from the dt prop erase-block-size, so it can be used to increase it.

but that's for later

JarmouniA

There are other MCUboot tests the board can be added to (see the H750B-DK PR).

boards/st/stm32h7s78_dk/stm32h7s78_dk-common.dtsi

JarmouniA · 2025-10-23T09:08:37Z

boards/st/stm32h7s78_dk/stm32h7s78_dk-common.dtsi

+		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)>;


Can you test samples/modules/lvgl/demos? On H750B-DK, it didn't work with MPU_IO (but worked with MPU_FLASH). On H573I-DK it did work (& with MPU_FLASH the board didn't boot), not sure why yet.

Display related features are not working yet when executed from external flash. Probably due to STM32_LTDC_FB_USE_SHARED_MULTI_HEAP, had no time to investigate this (likely related to use of multiple XSPI instances used in //)

Is everyone fine to put this as a notable issue that can still be investigated and fixed in RC ?

Display related features are not working yet

Weird, even samples/drivers/display?

Non-blocking, but could you try with MPU_FLASH attribute?

Is everyone fine to put this as a notable issue that can still be investigated and fixed in RC ?

Makes sense.

MPU_FLASH should be the correct configuration, as MPU_IO does not allow unaligned memory access. Would be interesting to find out, why the H573I-DK didn't boot with that configuration.
I fixed getting mem faults on the nucleo_h7s3l8 by setting the ext_flash to MPU_FLASH - see #99505 point 6

boards/st/stm32h7s78_dk/stm32h7s78_dk-common.dtsi

boards/st/stm32h7s78_dk/stm32h7s78_dk_stm32h7s7xx_ext_flash_app.dts

Add ext_flash_app variant to stm32h7s78_dk to allow building application running on ext flash. Largely based on A.Jarmouni's work to enable the same on stm32h750_dk in PR 97037. Signed-off-by: Erwan Gouriou <[email protected]>

…iant Now that ext_flash_app variant is available, it should be used for mcuboot related apps on this board. Signed-off-by: Erwan Gouriou <[email protected]>

Add debug using stlink gdbserver as an alternative to pyocd. Signed-off-by: Erwan Gouriou <[email protected]>

Actual available internal RAM size was wrong, fix it. Signed-off-by: Erwan Gouriou <[email protected]>

etienne-lms

LGTM

sonarqubecloud · 2025-10-24T12:28:39Z

Quality Gate passed

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0.0% Duplication on New Code

See analysis details on SonarQube Cloud

Add ext_flash_app variant to nucleo_h7s3l8 to allow building applications running on ext flash. Based on Erwan Gouriou's work on stm32h7s78_dk in PR zephyrproject-rtos#97992 (which is based on A.Jarmouni's work on stm32h750_dk in PR 97037). Signed-off-by: Thomas Decker <[email protected]>

github-actions bot added manifest manifest-mcuboot DNM (manifest) This PR should not be merged (controlled by action-manifest) labels Oct 21, 2025

erwango force-pushed the dev_h7dk_ext_app_flash branch from dae3619 to 1ddea9e Compare October 21, 2025 11:54

zephyrbot added area: Sysbuild platform: STM32 ST Micro STM32 area: MCUBoot area: Samples Samples area: Boards/SoCs labels Oct 21, 2025

erwango force-pushed the dev_h7dk_ext_app_flash branch from 1ddea9e to 8251c15 Compare October 21, 2025 11:56

zephyrbot requested review from 57300, FRASTM, GeorgeCGV, JarmouniA, d3zd3z, de-nordic, djiatsaf-st, etienne-lms, gautierg-st, kartben, marwaiehm-st, mathieuchopstm, nashif, nordicjm and tejlmand October 21, 2025 11:56

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maass-hamburg requested changes Oct 23, 2025

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erwango force-pushed the dev_h7dk_ext_app_flash branch from 4c675de to 0669808 Compare October 24, 2025 09:53

github-actions bot removed the DNM (manifest) This PR should not be merged (controlled by action-manifest) label Oct 24, 2025

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etienne-lms mentioned this pull request Oct 24, 2025

boards: st: correct or add RAM/Flash sizes in some ST boards YAML files #98198

Merged

erwango added 4 commits October 24, 2025 14:01

boards: st: stm32h7s78_dk: Add ext_flash_app variant

e6a22f7

Add ext_flash_app variant to stm32h7s78_dk to allow building application running on ext flash. Largely based on A.Jarmouni's work to enable the same on stm32h750_dk in PR 97037. Signed-off-by: Erwan Gouriou <[email protected]>

samples: sysbuild: with_mcuboot: stm32h7s78_dk: Use ext_flash_app var…

92e2386

…iant Now that ext_flash_app variant is available, it should be used for mcuboot related apps on this board. Signed-off-by: Erwan Gouriou <[email protected]>

boards: st: stm32h7s78_dk: Add debug using stlink gdbserver

f2b3205

Add debug using stlink gdbserver as an alternative to pyocd. Signed-off-by: Erwan Gouriou <[email protected]>

boards: st: stm32h7s78_dk: Fix ram size in board yaml file

1e20348

Actual available internal RAM size was wrong, fix it. Signed-off-by: Erwan Gouriou <[email protected]>

erwango force-pushed the dev_h7dk_ext_app_flash branch from 0669808 to 1e20348 Compare October 24, 2025 12:01

maass-hamburg requested review from JarmouniA and nordicjm October 24, 2025 12:05

maass-hamburg added this to the v4.3.0 milestone Oct 24, 2025

nordicjm approved these changes Oct 24, 2025

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etienne-lms approved these changes Oct 24, 2025

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JarmouniA approved these changes Oct 24, 2025

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maass-hamburg assigned erwango and unassigned tejlmand Oct 24, 2025

erwango assigned etienne-lms and unassigned erwango Oct 24, 2025

cfriedt merged commit e532f6a into zephyrproject-rtos:main Oct 24, 2025
29 checks passed

JarmouniA mentioned this pull request Nov 4, 2025

stm32: fix memc initialization to avoid XSPIM configuration is APP_IN_EXT_FLASH #98683

Merged

JarmouniA mentioned this pull request Nov 17, 2025

SoC STM32H7RS MPU configuration issues #99505

Open

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TD-JBL mentioned this pull request Nov 19, 2025

boards: st: nucleo_h7s3l8: Introduce App in Ext Flash variant #99647

Open

	erase-block-size = <DT_SIZE_K(128)>;
	erase-block-size = <DT_SIZE_K(4)>;

boards: stm32h7s78_dk: Introduce App in Ext Flash variant #97992

boards: stm32h7s78_dk: Introduce App in Ext Flash variant #97992

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