[PATCH] board: ea: mx7ulp_com: allocate specific region of memory to OP-TEE

[Oleksandr Suvorov]

Hi Tom,


On Wed, Aug 25, 2021 at 4:46 PM Tom Rini <trini at konsulko.com> wrote:
>
> On Wed, Aug 25, 2021 at 04:22:55PM +0300, Oleksandr Suvorov wrote:
>
> > From: Ricardo Salveti <ricardo at foundries.io>
> >
> > On the iMX7ULP uCOM board, OP-TEE uses the memory region defined by the
> > maximum DRAM address minus CONFIG_OPTEE_TZDRAM_SIZE, so subtract
> > CONFIG_OPTEE_TZDRAM_SIZE from the available DRAM size to avoid
> > conflicts.
> >
> > Note the OPTEE boot process itself subtracts the DRAM region it
> > lives in from the memory map passed to Linux.
>
> Is this something true of all OP-TEE?  All OP-TEE on ARMv7?  All OP-TEE
> on i.MX7?  I'm asking since currently this hook is done the exact same
> way on a few other i.MX7 boards, and nowhere else.  That says to me we
> should probably move this hook up somewhere, perhaps to imx_ddr_size()
> and poke the boards that aren't using that today to use it.

Shortly, no. There are different solutions for different boards and
they seem not
vendor-specific. Say, solutions for both stm32mp1 and zynqmp boards use fdt's
reserve memory section to avoid conflicts with the OP-TEE memory region.
We're thinking about providing a generic solution, but it will take
some time and
can't be done right now.

>
> --
> Tom


--
Best regards,

Oleksandr Suvorov
Software Engineer
W: www.foundries.io