Re: Proposal : Hart Suspend Extension for IDLE

liu shaohua <liush@...>

Hi Anup,
I have gained a lot from your information. Thank you very much.

1. SBI HSM HART SUSPEND call (with a parameter to specify platform specific CPU idle power mode)
In addition to "power_state", do we consider adding an address parameter “entrypoint”.It can be used to specify the adress where code execution resumes when a program is waken up. I think whether or not to configure the address parameters may affect the software flow after wake-up. Assuming that the address parameters are not configured, the runtime firmware may need to restore the state in all modes. If the address is configured, when waking up from the idle state, the runtime firmware only restores the state related to the M mode, and the OS restores the state related to the S mode.
> 2. Discovering supported SBI HART SUSPEND modes for given platform (Device Tree ?? ACPI ?? SBI Calls ??)
Do we need to add this additional configuration?
I learned that arm gets the parameters of Cx state from dts to fill the internal idle structure. If the Cx status parameter is not configured in the dts, it means that there will be no platform-related idle implementation, and the linux driver will not perform deeper idle behaviors.


liu shaohua

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