]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
cpuidle, ACPI: Evaluate LPI arch_flags for broadcast timer
authorOza Pawandeep <quic_poza@quicinc.com>
Tue, 3 Oct 2023 17:33:33 +0000 (10:33 -0700)
committerWill Deacon <will@kernel.org>
Wed, 4 Oct 2023 15:31:27 +0000 (16:31 +0100)
commit4785aa8028536c2be656d22c74ec1995b97056f3
treef95063294a84be0066324d15b6b05dcb213a95bb
parent471470bc7052d28ce125901877dd10e4c048e513
cpuidle, ACPI: Evaluate LPI arch_flags for broadcast timer

ArmĀ® Functional Fixed Hardware Specification defines LPI states,
which provide an architectural context loss flags field that can
be used to describe the context that might be lost when an LPI
state is entered.

- Core context Lost
        - General purpose registers.
        - Floating point and SIMD registers.
        - System registers, include the System register based
        - generic timer for the core.
        - Debug register in the core power domain.
        - PMU registers in the core power domain.
        - Trace register in the core power domain.
- Trace context loss
- GICR
- GICD

Qualcomm's custom CPUs preserves the architectural state,
including keeping the power domain for local timers active.
when core is power gated, the local timers are sufficient to
wake the core up without needing broadcast timer.

The patch fixes the evaluation of cpuidle arch_flags, and moves only to
broadcast timer if core context lost is defined in ACPI LPI.

Fixes: a36a7fecfe60 ("ACPI / processor_idle: Add support for Low Power Idle(LPI) states")
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Oza Pawandeep <quic_poza@quicinc.com>
Link: https://lore.kernel.org/r/20231003173333.2865323-1-quic_poza@quicinc.com
Signed-off-by: Will Deacon <will@kernel.org>
arch/arm64/include/asm/acpi.h
drivers/acpi/processor_idle.c
include/linux/acpi.h