Hi

I'm trying to wrap my head around the purpose of the following lines in ft_system_setup():

        if (!CONFIG_IS_ENABLED(OPTEE) ||
            !tee_find_device(NULL, NULL, NULL, NULL))
                stm32_fdt_disable_optee(blob);

My interpretation is "if optee is not running, delete the FDT node".
The problem is that tee_find_device() invokes device_probe(). This in turn does an SMC call. This call results in an abort and reboot if optee is not running in the first place.

So I don't think that tee_find_device() can be used as a check for "Is optee running?". Exhibit B: Outside of mach-stm32mp, tee_find_device() is used to obtain of a _working_ TEE node, not to ask if "is optee running?".


My problem is that trying to start linux with CONFIG_OPTEE=y will cause the bootm command to crash (log in appendix A):

        load mmc 0:7 $loadaddr boot/uImage
        load mmc 0:7 $fdt_addr_r boot/stm32mp157c-dk2.dtb
        load mmc 0:7 0xc8000000 boot/utee
        setenv bootm_boot_mode sec
        bootm 0xc8000000 - $fdt_addr_r

What is the intent of calling tee_find_device() in an FDT fixup function? Do you have any ideas how to make it not crash (short of commenting out the problem lines) ?

Alex


Appendix A: u-boot log after bootm command

## Booting kernel from Legacy Image at c8000000 ...
   Image Name:
   Created:      2020-09-28  20:58:56 UTC
Image Type: ARM Trusted Execution Environment Kernel Image (uncompressed)
   Data Size:    349276 Bytes = 341.1 KiB
   Load Address: fdffffe4
   Entry Point:  fe000000
   Verifying Checksum ... OK
   Loading Kernel Image
## Flattened Device Tree blob at c4000000
   Booting using the fdt blob at 0xc4000000
   Loading Device Tree to cffef000, end cffff5e2 ... OK
<BOARD RESETS WITHOUT USER INPUT>
U-Boot SPL 2020.10-rc4 (Sep 20 2020 - 23:46:47 +0000)
Model: STMicroelectronics STM32MP157C-DK2 Discovery Board

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