On Tue, Aug 31, 2021 at 01:20:48PM -0500, Nishanth Menon wrote:
With Device Manager firmware in an elf file form, we cannot load the FIT image to the exact same address as any of the executable sections of the elf file itself is located.
However, the device tree descriptions for the ARMV8 bootloader/OS includes DDR regions only the final sections in DDR where the Device Manager firmware is actually executing out of.
As the R5 uC is usually operating at a slower rate than an ARMv8 MPU, by starting the Armv8 ahead of parsing the elf and copying the correct sections to the required memories creates a race condition where the ARMv8 could overwrite the elf image loaded from the FIT image prior to the R5 completing parsing and putting the correct sections of elf in the required memory locations. OR create rather obscure debug conditions where data in the section is being modified by ARMV8 OS while the elf copy is in progress.
To prevent all these conditions, lets make sure that the elf parse and copy operations are completed ahead of ARMv8 being released to execute.
We will pay a penalty of elf copy time, but that is a valid tradeoff in comparison to debug of alternate scenarios.
Signed-off-by: Nishanth Menon nm@ti.com
Applied to u-boot/master, thanks!