Custom u-boot environment

[dhk112]

Hello everyone,

I am trying to migrate a project for the STM32MP151C from dunfell to kirkstone.

The versions of the main components I am using are the following:

Component	Version
tf-a-stm32mp	v2.6-stm32mp-r2.2
optee-os-stm32mp	v3.16.0-stm32mp-r2.2
u-boot-stm32mp	v2021.10-stm32mp-r2.2
linux-stm32mp	v5.15.145-stm32mp-r2.2

The project intends to have a custom u-boot environment. For this a patch is applied to modify CONFIG_EXTRA_ENV_SETTINGS in stm32mp15_common.h, like this:

#define FOO_USBFLASH_BOOTFS "foo_usbflash_bootfs=" \
	"load usb 0:1 ${loadaddr} foo-image-bootfs-foo-core-stm32mp151c-foo.ext4;" \
	"mmc write ${loadaddr} 2400 20000;" \
	"mmc write ${loadaddr} 22400 20000;\0"


#define CONFIG_EXTRA_ENV_SETTINGS \
	STM32MP_MEM_LAYOUT \
	STM32MP_BOOTCMD \
	STM32MP_PARTS_DEFAULT \
	BOOTENV \
	FOO_USBFLASH_BOOTFS \
	STM32MP_EXTRA \
	STM32MP_BOARD_EXTRA_ENV

This approach worked perfectly fine in the old version of the project, but now when the system boots into u-boot I see that the custom u-boot environment is not present anymore.

I use the following flashlayout:

#Opt	Id	Name	Type	IP	Offset	Binary
-	0x01	fsbl-boot	Binary	none	0x0	arm-trusted-firmware/tf-a-stm32mp151c-foo-uart.stm32
-	0x03	fip-boot	FIP	none	0x0	fip/fip-stm32mp151c-foo-optee.bin
P	0x04	fsbl	Binary	mmc0	boot1	arm-trusted-firmware/tf-a-stm32mp151c-foo-emmc.stm32
P	0x05	fsbl2	Binary	mmc0	boot2	arm-trusted-firmware/tf-a-stm32mp151c-foo-emmc.stm32
P	0x06	metadata1	Binary	mmc0	0x00080000	arm-trusted-firmware/metadata.bin
P	0x07	metadata2	Binary	mmc0	0x00100000	arm-trusted-firmware/metadata.bin
P	0x08	fip-a	FIP	mmc0	0x00180000	fip/fip-stm32mp151c-foo-optee.bin
P	0x09	fip-b	FIP	mmc0	0x00580000	fip/fip-stm32mp151c-foo-optee.bin
PED	0x0A	u-boot-env	Binary	mmc0	0x00980000	none
P	0x10	boot1	System	mmc0	0x00A00000	pseudo.ext4
P	0x11	boot2	System	mmc0	0x04A00000	pseudo.ext4
P	0x12	super1	FileSystem	mmc0	0x08A00000	pseudo.ext4
P	0x13	super2	FileSystem	mmc0	0x66600000	pseudo.ext4
P	0x14	data	FileSystem	mmc0	0xC4200000	pseudo.ext4

What additional settings are needed for my custom u-boot environment to work?

[dhk112 · Accepted solution]

I managed to figure this out myself.

So the goal was to have a compiled-in (default) u-boot environment.

It was a combination of two things:

1. Modification of CONFIG_EXTRA_ENV_SETTINGS

Apparently in the kirkstone version there are two header files where CONFIG_EXTRA_ENV_SETTINGS is defined:

• stm32mp15_common.h
• stm32mp15_st_common.h

Whereby in stm32mp15_st_common.h the following can be found:

#ifdef CONFIG_EXTRA_ENV_SETTINGS
//...
#undef CONFIG_EXTRA_ENV_SETTINGS
#define CONFIG_EXTRA_ENV_SETTINGS

I don't get what the purpose is to undefine CONFIG_EXTRA_ENV_SETTINGS here, but the result is that the extra environment variables have to be put into 

• stm32mp15_st_common.h

to take effect.

2. Configuration flags CONFIG_ENV_IN_*

There are multiple configuration flags in stm32mp15_defconfig which relate to where u-boot shall search for the environment. By default all of them are enabled:

• CONFIG_ENV_IS_NOWHERE=y
• CONFIG_ENV_IS_IN_MMC=y
• CONFIG_ENV_IS_IN_SPI_FLASH=y
• CONFIG_ENV_IS_IN_UBI=y

 To only have the compiled-in (default) environment I applied a patch like this:

 CONFIG_ENV_IS_NOWHERE=y
-CONFIG_ENV_IS_IN_MMC=y
-CONFIG_ENV_IS_IN_SPI_FLASH=y
-CONFIG_ENV_IS_IN_UBI=y
+CONFIG_ENV_IS_IN_MMC=n
+CONFIG_ENV_IS_IN_SPI_FLASH=n
+CONFIG_ENV_IS_IN_UBI=n

Note: This should also be changed in stm32mp15_trusted_defconfig