On Fri, Sep 29, 2023 at 04:04:59PM +0100, Will Deacon wrote:
> On Mon, Sep 18, 2023 at 10:21:40AM -0700, Oza Pawandeep wrote:
> > Arm® 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: a36a7fecfe607 ("Add support for Low Power Idle(LPI) states")
> > Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> > Acked-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>
> > Signed-off-by: Oza Pawandeep <quic_poza@xxxxxxxxxxx>
> > ---
> >
> > Notes:
> > Will/Catalin: Rafael has acked and he prefers to take it via arm64 tree
> >
> > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> > index 4d537d56eb84..269d21209723 100644
> > --- a/arch/arm64/include/asm/acpi.h
> > +++ b/arch/arm64/include/asm/acpi.h
> > @@ -9,6 +9,7 @@
> > #ifndef _ASM_ACPI_H
> > #define _ASM_ACPI_H
> >
> > +#include <linux/cpuidle.h>
> > #include <linux/efi.h>
> > #include <linux/memblock.h>
> > #include <linux/psci.h>
> > @@ -44,6 +45,23 @@
> >
> > #define ACPI_MADT_GICC_TRBE (offsetof(struct acpi_madt_generic_interrupt, \
> > trbe_interrupt) + sizeof(u16))
> > +/*
> > + * Arm® Functional Fixed Hardware Specification Version 1.2.
> > + * Table 2: Arm Architecture context loss flags
> > + */
> > +#define CPUIDLE_CORE_CTXT BIT(0) /* Core context Lost */
> > +
> > +static __always_inline void _arch_update_idle_state_flags(u32 arch_flags,
> > + unsigned int *sflags)
>
> Why can't this just be 'static inline'?
>
> > +{
> > + if (arch_flags & CPUIDLE_CORE_CTXT)
> > + *sflags |= CPUIDLE_FLAG_TIMER_STOP;
> > +}
> > +#define arch_update_idle_state_flags _arch_update_idle_state_flags
>
> Usually, the function and the macro have the same name for this pattern,
> so I think it would be more consistent to drop the leading underscore
> from the C function name.
>
Sorry that's me telling him looking at some other example I think. I don't
have a strong opinion, just referred examples doing this way I guess.
Oza, please check it to as it was before I requested this.
--
Regards,
Sudeep
