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Date:   Mon, 12 Dec 2022 11:29:28 +0800
From:   Huang Rui <ray.huang@amd.com>
To:     "Yuan, Perry" <Perry.Yuan@amd.com>
Cc:     "rafael.j.wysocki@intel.com" <rafael.j.wysocki@intel.com>,
        "Limonciello, Mario" <Mario.Limonciello@amd.com>,
        "viresh.kumar@linaro.org" <viresh.kumar@linaro.org>,
        "Sharma, Deepak" <Deepak.Sharma@amd.com>,
        "Fontenot, Nathan" <Nathan.Fontenot@amd.com>,
        "Deucher, Alexander" <Alexander.Deucher@amd.com>,
        "Huang, Shimmer" <Shimmer.Huang@amd.com>,
        "Du, Xiaojian" <Xiaojian.Du@amd.com>,
        "Meng, Li (Jassmine)" <Li.Meng@amd.com>,
        "Karny, Wyes" <Wyes.Karny@amd.com>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 01/13] ACPI: CPPC: Add AMD pstate energy performance
 preference cppc control
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References: <20221208111852.386731-1-perry.yuan@amd.com>
 <20221208111852.386731-2-perry.yuan@amd.com>
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On Fri, Dec 09, 2022 at 03:55:28PM +0800, Huang Rui wrote:
> On Thu, Dec 08, 2022 at 07:18:40PM +0800, Yuan, Perry wrote:
> > From: Perry Yuan <Perry.Yuan@amd.com>
> > 
> > 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
> > 
> > Downstream drivers that want to use the new symbols cppc_get_epp_caps
> > and cppc_set_epp_perf for querying and setting EPP preferences will need
> > to call cppc_set_auto_epp to enable the EPP function first.
> > 
> > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> 
> Acked-by: Huang Rui <ray.huang@amd.com>
> 
> > ---
> >  drivers/acpi/cppc_acpi.c | 114 +++++++++++++++++++++++++++++++++++++--
> >  include/acpi/cppc_acpi.h |  12 +++++
> >  2 files changed, 121 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> > index 093675b1a1ff..37fa75f25f62 100644
> > --- a/drivers/acpi/cppc_acpi.c
> > +++ b/drivers/acpi/cppc_acpi.c
> > @@ -1093,6 +1093,9 @@ static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
> >  {
> >  	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
> >  	struct cpc_register_resource *reg;
> > +	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
> > +	struct cppc_pcc_data *pcc_ss_data = NULL;
> > +	int ret = -EINVAL;
> >  
> >  	if (!cpc_desc) {
> >  		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
> > @@ -1102,10 +1105,6 @@ static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
> >  	reg = &cpc_desc->cpc_regs[reg_idx];
> >  
> >  	if (CPC_IN_PCC(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 -EIO;
> >  
> > @@ -1125,7 +1124,7 @@ static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
> >  
> >  	cpc_read(cpunum, reg, perf);
> >  
> > -	return 0;
> > +	return ret;
> >  }
> >  
> >  /**
> > @@ -1365,6 +1364,111 @@ 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)

Take a look at the patch again, due to the energy_perf is actually one of
the members in struct cppc_perf_caps. It's better to modify the existing
cppc_get_perf_caps() to get the epp value as well.

Thanks,
Ray

> > +{
> > +	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_debug("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_once("energy perf reg update is unsupported!\n");
> > +
> > +	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);
> > +
> > +/*
> > + * Set Energy Performance Preference Register value through
> > + * Performance Controls Interface
> > + */
> > +int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
> > +{
> > +	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
> > +	struct cpc_register_resource *epp_set_reg;
> > +	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_debug("No CPC descriptor for CPU:%d\n", cpu);
> > +		return -ENODEV;
> > +	}
> > +
> > +	auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
> > +	epp_set_reg = &cpc_desc->cpc_regs[ENERGY_PERF];
> > +
> > +	if (CPC_IN_PCC(epp_set_reg) || CPC_IN_PCC(auto_sel_reg)) {
> > +		if (pcc_ss_id < 0) {
> > +			pr_debug("Invalid pcc_ss_id\n");
> > +			return -ENODEV;
> > +		}
> > +
> > +		if (CPC_SUPPORTED(auto_sel_reg)) {
> > +			ret = cpc_write(cpu, auto_sel_reg, enable);
> > +			if (ret)
> > +				return ret;
> > +		}
> > +
> > +		if (CPC_SUPPORTED(epp_set_reg)) {
> > +			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);
> > +	} else {
> > +		ret = -ENOTSUPP;
> > +		pr_debug("_CPC in PCC is not supported\n");
> > +	}
> > +
> > +	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..a45bb876a19c 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 +151,8 @@ 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_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, bool enable);
> >  #else /* !CONFIG_ACPI_CPPC_LIB */
> >  static inline int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
> >  {
> > @@ -202,6 +206,14 @@ static inline int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
> >  {
> >  	return -ENOTSUPP;
> >  }
> > +static inline int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
> > +{
> > +	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*/
> > -- 
> > 2.34.1
> >