Re: [PATCH v2 0/4] Implement vendor resets for PSCI SYSTEM_RESET2

Sudeep Holla
2024-04-16T09:35:28Z

On Sun, Apr 14, 2024 at 12:30:23PM -0700, Elliot Berman wrote:
> The PSCI SYSTEM_RESET2 call allows vendor firmware to define additional
> reset types which could be mapped to the reboot argument.
>
> Setting up reboot on Qualcomm devices can be inconsistent from chipset
> to chipset.

That doesn't sound good. Do you mean PSCI SYSTEM_RESET doesn't work as
expected ? Does it mean it is not conformant to the specification ?

> Generally, there is a PMIC register that gets written to
> decide the reboot type. There is also sometimes a cookie that can be
> written to indicate that the bootloader should behave differently than a
> regular boot. These knobs evolve over product generations and require
> more drivers. Qualcomm firmwares are beginning to expose vendor
> SYSTEM_RESET2 types to simplify driver requirements from Linux.
>

Why can't this be fully userspace driven ? What is the need to keep the
cookie in the DT ?

--
Regards,
Sudeep