Booting directly to kernel from TFA on stm32mp157DAC

[adnan_pasha]

Hi,

I am working on optimizing the boot process on my STM32MP157DAC board by removing U-Boot and booting the Linux kernel directly. I’ve been following the documented procedure from ST for the STM32MP1 series:
ST Wiki - How to optimize the boot time

TF-A Configuration

I’ve updated the configuration in stm32mp1_def.h as follows:

1. • #define STM32MP_BL33_BASE (STM32MP_DDR_BASE + U(0x2008000))

     #define STM32MP_BL33_MAX_SIZE U(0x3FF8000)

2. SD Card Timeout Modification

   Modified the SD card timeout value in <tf-a_sources>/drivers/st/mmc/stm32_sdmmc2.c:

   • timeout = timeout_init_us(TIMEOUT_US_1_S * 10);

3. TF-A Build Process:

   • I applied the changes as a patch through my custom Yocto layer and rebuilt the tf-a-stm32mp recipe successfully.

4. Kernel Configuration:

   • • I added the following configuration parameters to my stm32_defconfig:
       CONFIG_CMDLINE_BOOL=y
       CONFIG_CMDLINE="root=PARTUUID=e91c4e10-16e6-4c0e-bd0e-77becf4a3582 rootwait rw earlyprintk earlycon console=ttySTM0,115200"

     • I created and applied a patch for this as well via my custom Yocto layer.

5. FIP Tool Update:

   • I updated the FIP image using fiptool:

     fiptool update --nt-fw kernel/uImage --hw-config kernel/stm32mp157f-dk2.dtb fip/fip-stm32mp157f-dk2-optee-sdcard.bin

   • The result was the new FIP file: fip-stm32mp157f-dk2-optee-sdcard.bin

6. Flash Layout Modification:

   • I modified the TSV file as follows to include the new TF-A and FIP binaries:

     #Opt	Id	Name	Type	IP	Offset	Binary
     -	0x01	fsbl-boot	Binary	none	0x0	arm-trusted-firmware/tf-a-stm32mp157f-dk2-usb.stm32
     -	0x03	fip-boot	FIP	none	0x0	fip/fip-stm32mp157f-dk2-optee-emmc.bin
     P	0x04	fsbl1	Binary	mmc1	boot1	arm-trusted-firmware/tf-a-stm32mp157f-dk2-optee-emmc.stm32
     P	0x05	fsbl2	Binary	mmc1	boot2	arm-trusted-firmware/tf-a-stm32mp157f-dk2-optee-emmc.stm32
     P	0x06	metadata1	FWU_MDATA	mmc1	0x00080000	arm-trusted-firmware/metadata.bin
     P	0x07	metadata2	FWU_MDATA	mmc1	0x00100000	arm-trusted-firmware/metadata.bin
     P	0x08	fip-a	FIP	mmc1	0x00180000	fip/fip-stm32mp157f-dk2-optee-emmc.bin
     PED	0x09	fip-b	FIP	mmc1	0x02180000	none
     PED	0x0A	u-boot-env	ENV	mmc1	0x02580000	none
     P	0x10	bootfs	System	mmc1	0x02600000	st-image-bootfs-openstlinux-weston-stm32mp15-disco.ext4
     P	0x11	vendorfs	FileSystem	mmc1	0x06600000	st-image-vendorfs-openstlinux-weston-stm32mp15-disco.ext4
     P	0x12	rootfs	FileSystem	mmc1	0x07600000	st-image-qt-openstlinux-weston-stm32mp15-disco.ext4

When attempting to flash the image using STM32CubeProgrammer, I receive a timeout error indicating "unable to reconnect", and the operation fails at partition 0x03.

I’ve also attached the patch with my TF-A and kernel changes. Please let me know if there’s anything I may have missed or need to correct.

For reference, I’ve reviewed a related thread on ST’s community forum:
Direct kernel boot on STM32MP1

Thanks.