Re: [PATCH v5 04/11] ACPI: CPPC: Extend cppc_set_epp_perf() to support auto_sel and epp

[Sumit Gupta]

On 25/12/25 09:26, zhenglifeng (A) wrote:
> External email: Use caution opening links or attachments
>
>
> On 2025/12/23 20:13, Sumit Gupta wrote:
> > Extend cppc_set_epp_perf() to write both auto_sel and energy_perf
> > registers when they are in FFH or SystemMemory address space.
> >
> > This keeps the behavior consistent with PCC case where both registers
> > are already updated together, but was missing for FFH/SystemMemory.
> >
> > Also update EPP constants for better clarity:
> > - Add CPPC_EPP_PERFORMANCE_PREF (0x00) for performance preference
> > - Add CPPC_EPP_ENERGY_EFFICIENCY_PREF (0xFF) for energy efficiency
> >
> > Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
> > ---
> >   drivers/acpi/cppc_acpi.c | 35 +++++++++++++++++++++++++++++------
> >   include/acpi/cppc_acpi.h |  3 ++-
> >   2 files changed, 31 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> > index a4e89fe6aab5..403ee988a8c6 100644
> > --- a/drivers/acpi/cppc_acpi.c
> > +++ b/drivers/acpi/cppc_acpi.c
> > @@ -1556,6 +1556,8 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
> >        struct cpc_register_resource *auto_sel_reg;
> >        struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
> >        struct cppc_pcc_data *pcc_ss_data = NULL;
> > +     bool autosel_ffh_sysmem;
> > +     bool epp_ffh_sysmem;
> >        int ret;
> >
> >        if (!cpc_desc) {
> > @@ -1566,6 +1568,11 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
> >        auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
> >        epp_set_reg = &cpc_desc->cpc_regs[ENERGY_PERF];
> >
> > +     epp_ffh_sysmem = CPC_SUPPORTED(epp_set_reg) &&
> > +             (CPC_IN_FFH(epp_set_reg) || CPC_IN_SYSTEM_MEMORY(epp_set_reg));
> > +     autosel_ffh_sysmem = CPC_SUPPORTED(auto_sel_reg) &&
> > +             (CPC_IN_FFH(auto_sel_reg) || CPC_IN_SYSTEM_MEMORY(auto_sel_reg));
> > +
> >        if (CPC_IN_PCC(epp_set_reg) || CPC_IN_PCC(auto_sel_reg)) {
> >                if (pcc_ss_id < 0) {
> >                        pr_debug("Invalid pcc_ss_id for CPU:%d\n", cpu);
> > @@ -1590,14 +1597,30 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
> >                /* after writing CPC, transfer the ownership of PCC to platform */
> >                ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
> >                up_write(&pcc_ss_data->pcc_lock);
> > -     } else if (osc_cpc_flexible_adr_space_confirmed &&
> > -                CPC_SUPPORTED(epp_set_reg) && CPC_IN_FFH(epp_set_reg)) {
> > -             ret = cpc_write(cpu, epp_set_reg, perf_ctrls->energy_perf);
> > +     } else if (osc_cpc_flexible_adr_space_confirmed) {
> > +             if (!epp_ffh_sysmem && !autosel_ffh_sysmem) {
> > +                     ret = -EOPNOTSUPP;
> > +             } else {
> I think this can do the same thing:
>
>          } else if (osc_cpc_flexible_adr_space_confirmed &&
>                     (epp_ffh_sysmem || autosel_ffh_sysmem)) {
>
> and reduce the levels of indentation.

Thanks for suggesting. Will change in v6.

> > +                     if (autosel_ffh_sysmem) {
> > +                             ret = cpc_write(cpu, auto_sel_reg, enable);
> > +                             if (ret)
> > +                                     return ret;
> > +                     }
> > +
> > +                     if (epp_ffh_sysmem) {
> > +                             ret = cpc_write(cpu, epp_set_reg,
> > +                                             perf_ctrls->energy_perf);
> > +                             if (ret)
> > +                                     return ret;
> > +                     }
> > +             }
> >        } else {
> > -             ret = -ENOTSUPP;
> > -             pr_debug("_CPC in PCC and _CPC in FFH are not supported\n");
> > +             ret = -EOPNOTSUPP;
> >        }
> >
> > +     if (ret == -EOPNOTSUPP)
> > +             pr_debug("CPU%d: _CPC not in PCC/FFH/SystemMemory\n", cpu);
> > +
> >        return ret;
> >   }
> >   EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
> The code below is unrelated to the code above and should ideally be
> separated into a separate patch I think.

Will move it to a separate patch in v6.

Thank you,
Sumit Gupta

> > @@ -1609,7 +1632,7 @@ EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
> >    */
> >   int cppc_set_epp(int cpu, u64 epp_val)
> >   {
> > -     if (epp_val > CPPC_ENERGY_PERF_MAX)
> > +     if (epp_val > CPPC_EPP_ENERGY_EFFICIENCY_PREF)
> >                return -EINVAL;
> >
> >        return cppc_set_reg_val(cpu, ENERGY_PERF, epp_val);
> > diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> > index 12a1dc31bf2a..2860a0252313 100644
> > --- a/include/acpi/cppc_acpi.h
> > +++ b/include/acpi/cppc_acpi.h
> > @@ -39,7 +39,8 @@
> >   /* CPPC_AUTO_ACT_WINDOW_MAX_SIG is 127, so 128 and 129 will decay to 127 when writing */
> >   #define CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH 129
> >
> > -#define CPPC_ENERGY_PERF_MAX (0xFF)
> > +#define CPPC_EPP_PERFORMANCE_PREF            0x00
> > +#define CPPC_EPP_ENERGY_EFFICIENCY_PREF              0xFF
> >
> >   /* Each register has the folowing format. */
> >   struct cpc_reg {