[Mo.Elhawy]

Thanks Neeraj,
Your reply was quite clear and helpful, but applying only these modifications to u-boot device tree wasn’t enough to get the Kernel to be booted, the second stage boot loader (u-boot) still checks for Stm32CubeProgrammer pin and if it is active the boot loader doesn’t load the Kernel. I found some solutions to overcome this problem for any image that is configured for DK2 board.

•  Modifying stm32mp1.c file in u-boot source to stop the boot loader from checking the Stm32CubeProgrammer pin (PA14), this check is on board_key_check() function in the below lines:

if (gpio_request_by_name_nodev(node, "st,stm32prog-gpios", 0, &gpio, GPIOD_IS_IN)) { debug("%s: could not find a /config/st,stm32prog-gpios\n", __func__); } else { if (dm_gpio_get_value(&gpio)) { puts("STM32Programmer key pressed, "); boot_mode = BOOT_STM32PROG; } dm_gpio_free(NULL, &gpio); } I have also attached the modified file with these lines commented (lines 147 to 159)

1 2 3 4 5 6 7 8 9 10 11 12 13

if (gpio_request_by_name_nodev(node, "st,stm32prog-gpios", 0,        &gpio, GPIOD_IS_IN)) { debug("%s: could not find a /config/st,stm32prog-gpios\n",       __func__); } else { if (dm_gpio_get_value(&gpio)) { puts("STM32Programmer key pressed, "); boot_mode = BOOT_STM32PROG; } dm_gpio_free(NULL, &gpio); }   I have also attached the modified file with these lines commented (lines 147 to 159)

• Connecting PA14 pin on the board to logic high.
• Changing PA14 configuration in the device tree from active low to active high.  (stm32mp157a-dk1-u-boot.dtsi line 22), I am not sure if removing the configuration for PA14 by removing this line may cause any problems.

Best regards,

Elhawy

 

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