[U-Boot] [PATCH v2 6/9] tools: mkimage: add optee image type

[Bryan O'Donoghue]

On 22/01/18 14:46, Andrew F. Davis wrote:

>> As I understand it, that's a board-specific method, which wants to
>> install a TEE (jump into a TEE and return to u-boot), whereas the aim
>> with this patch-set is to chain-load and boot via TEE - OPTEE in this case.
>>
> 
> This is not board-specific, this is the flow all ARM boards I know of
> use (except i.MX 6).

The OPTEE port I'm working with is i.MX 7, which chain-loads in this 
same way.

> Is there some technical reason I am missing as to why you want to use
> this alternate flow?

The reason is the upstream OPTEE port we are working with already uses 
this bootflow.

>> The example from Peng Fang
>>
>>>> mkimage -A arm -O linux -C none -a 0x9c0fffe4 -e 0x9c100000 -d
>>>> ./out/arm-plat-imx/core/tee.bin uTee
>>
> 
> I haven't used mkimage in a while, but how is this any different than
> what we do with the kernel image? Why do we need to pull this info out
> of the header when we don't do the same for Linux?

So for a kernel you are typically making a uImage of a compressed kernel 
image and therefore you have to pass load-address and entry point.

mkimage -A arm -O linux -T kernel -C none -a 0x80008000 -e 0x80008000 -n 
"Linux kernel" -d arch/arm/boot/zImage uImage

For the bootable OPTEE image case I'm proposing

1. A distinct image type
2. Based on that image type we validate the OPTEE header
    MAGIC, version, etc
3. Based on the OPTEE header we can validate the location the OPTEE
    binary gets loaded to.

Having a distinct image type makes it more robust.

>>>> mkimage -A arm -T optee -C none -d ./out/arm-plat-imx/core/tee.bin
>>> and remove the requirement to pass load and entry point on the command
>> line.
>>
> To me the save in this command (which should be handled automatically
> during the build process),

As above, it's about image generation, validation and load-address 
sanity checking.

I apologize for not making that clearer upfront - my bad, I'll attempt 
to flesh-out the patch descriptions to make the logic clearer.

---
bod