Function sbi_rt::system_suspend

source ·

pub fn system_suspend<T>(
    sleep_type: T,
    resume_addr: usize,
    opaque: usize
) -> SbiRetwhere
    T: SleepType,

Expand description

Suspend the system based on provided sleep_type.

§Parameters

The sleep_type parameter specifies the sleep type.

Type	Name	Description
0	SUSPEND_TO_RAM	This is a “suspend to RAM” sleep type, similar to ACPI’s S2 or S3. Entry requires all but the calling hart be in the HSM `STOPPED` state and all hart registers and CSRs saved to RAM.
0x00000001 - 0x7fffffff		Reserved for future use
0x80000000 - 0xffffffff		Platform-specific system sleep types

The resume_addr parameter points to a runtime-specified physical address, where the hart can resume execution in supervisor-mode after a system suspend.

The opaque parameter is an XLEN-bit value that will be set in the a1 register when the hart resumes execution at resume_addr after a system suspend.

§Return value

The possible return error codes returned in SbiRet.error are shown in the table below:

Return code	Description
`SbiRet::success()`	The suspend request is accepted, and the system is suspended. The system will resume execution at `resume_addr` after the sleep period.
`SbiRet::invalid_param()`	`sleep_type` is reserved or is platform-specific and unimplemented.
`SbiRet::not_supported()`	`sleep_type` is not reserved and is implemented, but the platform does not support it due to one or more missing dependencies.
`SbiRet::invalid_address()`	`resume_addr` is not valid, possibly due to the following reasons: + * It is not a valid physical address. + * Executable access to the address is prohibited by a physical memory protection mechanism or H-extension G-stage for supervisor mode.
`SbiRet::denied()`	The suspend request failed due to unsatisfied entry criteria.
`SbiRet::failed()`	The suspend request failed for unspecified or unknown other reasons.

This function is defined in RISC-V SBI Specification chapter 13.1.