Messages in this thread | | | Date | Mon, 7 Nov 2022 12:44:35 -0600 | Subject | Re: [PATCH v3 1/8] ACPI: CPPC: Add AMD pstate energy performance preference cppc control | From | "Limonciello, Mario" <> |
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On 11/7/2022 11:56, Perry Yuan wrote: > Add the EPP(Energy Performance Preference) support for the > AMD SoCs without the dedicated CPPC MSR, those SoCs need to add this > cppc acpi functions to update EPP values and desired perf value.
As far as I can tell this is generic code. Although the reason you're submitting it is for enabling AMD SoCs, the commit message should be worded as such.
> > In order to get EPP worked, cppc_get_epp_caps() will query EPP preference > value and cppc_set_epp_perf() will set EPP new value. > Before the EPP works, pstate driver will use cppc_set_auto_epp() to > enable EPP function from firmware firstly.
This could more succinctly say:
"Add support for setting and querying EPP preferences to the generic CPPC driver. This enables downstream drivers such as amd-pstate to discover and use these values."
> > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com> > --- > drivers/acpi/cppc_acpi.c | 126 +++++++++++++++++++++++++++++++++++++++ > include/acpi/cppc_acpi.h | 17 ++++++ > 2 files changed, 143 insertions(+) > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c > index 093675b1a1ff..d9c38dee1f48 100644 > --- a/drivers/acpi/cppc_acpi.c > +++ b/drivers/acpi/cppc_acpi.c > @@ -1365,6 +1365,132 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs) > } > EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs); > > +/** > + * cppc_get_epp_caps - Get the energy preference register value. > + * @cpunum: CPU from which to get epp preference level. > + * @perf_caps: Return address. > + * > + * Return: 0 for success, -EIO otherwise. > + */ > +int cppc_get_epp_caps(int cpunum, struct cppc_perf_caps *perf_caps) > +{ > + struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum); > + struct cpc_register_resource *energy_perf_reg; > + u64 energy_perf; > + > + if (!cpc_desc) { > + pr_warn("No CPC descriptor for CPU:%d\n", cpunum); > + return -ENODEV; > + } > + > + energy_perf_reg = &cpc_desc->cpc_regs[ENERGY_PERF]; > + > + if (!CPC_SUPPORTED(energy_perf_reg)) > + pr_warn("energy perf reg update is unsupported!\n");
No need to add a explanation point at the end.
As this is a per-CPU message I wonder if this would be better as pr_warn_once()? Othewrise some systems with large numbers of cores might potentially show this message quite a few times.
> + > + if (CPC_IN_PCC(energy_perf_reg)) { > + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum); > + struct cppc_pcc_data *pcc_ss_data = NULL; > + int ret = 0; > + > + if (pcc_ss_id < 0) > + return -ENODEV; > + > + pcc_ss_data = pcc_data[pcc_ss_id]; > + > + down_write(&pcc_ss_data->pcc_lock); > + > + if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0) { > + cpc_read(cpunum, energy_perf_reg, &energy_perf); > + perf_caps->energy_perf = energy_perf; > + } else { > + ret = -EIO; > + } > + > + up_write(&pcc_ss_data->pcc_lock); > + > + return ret; > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(cppc_get_epp_caps); > + > +int cppc_set_auto_epp(int cpu, bool enable) > +{ > + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu); > + 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; > + int ret = -EINVAL; > + > + if (!cpc_desc) { > + pr_warn("No CPC descriptor for CPU:%d\n", cpu);
Is this actually warn worthy? I would think it's fine a debug like we have for the other _CPC missing messages.
> + return -EINVAL; > + } > + > + auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE]; > + > + if (CPC_IN_PCC(auto_sel_reg)) { > + if (pcc_ss_id < 0) > + return -ENODEV; > + > + ret = cpc_write(cpu, auto_sel_reg, enable); > + if (ret) > + return ret; > + > + pcc_ss_data = pcc_data[pcc_ss_id]; > + > + down_write(&pcc_ss_data->pcc_lock); > + /* 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); > + return ret; > + } > + > + return cpc_write(cpu, auto_sel_reg, enable); > +} > +EXPORT_SYMBOL_GPL(cppc_set_auto_epp); > + > +/* > + * Set Energy Performance Preference Register value through > + * Performance Controls Interface > + */ > +int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) > +{ > + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu); > + struct cpc_register_resource *epp_set_reg; > + struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu); > + struct cppc_pcc_data *pcc_ss_data = NULL; > + int ret = -EINVAL; > + > + if (!cpc_desc) { > + pr_warn("No CPC descriptor for CPU:%d\n", cpu);
Is this actually warn worthy? I would think it's fine a debug like we have for the other _CPC missing messages.
> + return -EINVAL; > + } > + > + epp_set_reg = &cpc_desc->cpc_regs[ENERGY_PERF]; > + > + if (CPC_IN_PCC(epp_set_reg)) { > + if (pcc_ss_id < 0) > + return -ENODEV; > + > + ret = cpc_write(cpu, epp_set_reg, perf_ctrls->energy_perf); > + if (ret) > + return ret; > + > + pcc_ss_data = pcc_data[pcc_ss_id]; > + > + down_write(&pcc_ss_data->pcc_lock); > + /* 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);
cppc_set_auto_epp and cppc_set_epp_perf have nearly the same code in the if block. I wonder if it's worth having a static helper function for this purpose that takes "reg" and "value" as arguments?
> + } > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(cppc_set_epp_perf); > + > /** > * cppc_set_enable - Set to enable CPPC on the processor by writing the > * Continuous Performance Control package EnableRegister field. > diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h > index c5614444031f..10d91aeedaca 100644 > --- a/include/acpi/cppc_acpi.h > +++ b/include/acpi/cppc_acpi.h > @@ -108,12 +108,14 @@ struct cppc_perf_caps { > u32 lowest_nonlinear_perf; > u32 lowest_freq; > u32 nominal_freq; > + u32 energy_perf; > }; > > struct cppc_perf_ctrls { > u32 max_perf; > u32 min_perf; > u32 desired_perf; > + u32 energy_perf; > }; > > struct cppc_perf_fb_ctrs { > @@ -149,6 +151,9 @@ extern bool cpc_ffh_supported(void); > extern bool cpc_supported_by_cpu(void); > extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val); > extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val); > +extern int cppc_set_auto_epp(int cpu, bool enable); > +extern int cppc_get_epp_caps(int cpunum, struct cppc_perf_caps *perf_caps); > +extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls); > #else /* !CONFIG_ACPI_CPPC_LIB */ > static inline int cppc_get_desired_perf(int cpunum, u64 *desired_perf) > { > @@ -202,6 +207,18 @@ static inline int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val) > { > return -ENOTSUPP; > } > +static inline int cppc_set_auto_epp(int cpu, bool enable) > +{ > + return -ENOTSUPP; > +} > +static inline int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) > +{ > + return -ENOTSUPP; > +} > +static inline int cppc_get_epp_caps(int cpunum, struct cppc_perf_caps *perf_caps) > +{ > + return -ENOTSUPP; > +} > #endif /* !CONFIG_ACPI_CPPC_LIB */ > > #endif /* _CPPC_ACPI_H*/
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