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_epp_perf to enable the EPP function firstly.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
---
 drivers/acpi/cppc_acpi.c | 76 +++++++++++++++++++++++++++++++++++++---
 include/acpi/cppc_acpi.h | 12 +++++++
 2 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 093675b1a1ff..81081eb899ea 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;
 }
 
 /**
@@ -1153,6 +1152,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
 	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
 }
 
+/**
+ * cppc_get_epp_perf - Get the epp register value.
+ * @cpunum: CPU from which to get epp preference value.
+ * @epp_perf: Return address.
+ *
+ * Return: 0 for success, -EIO otherwise.
+ */
+int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
+{
+	return cppc_get_perf(cpunum, ENERGY_PERF, epp_perf);
+}
+EXPORT_SYMBOL_GPL(cppc_get_epp_perf);
+
 /**
  * cppc_get_perf_caps - Get a CPU's performance capabilities.
  * @cpunum: CPU from which to get capabilities info.
@@ -1365,6 +1377,60 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
 }
 EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
 
+/*
+ * 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..6b487a5bd638 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_perf(int cpunum, u64 *epp_perf);
+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_perf(int cpunum, u64 *epp_perf)
+{
+	return -ENOTSUPP;
+}
 #endif /* !CONFIG_ACPI_CPPC_LIB */
 
 #endif /* _CPPC_ACPI_H*/
-- 
2.34.1

On Mon, Dec 19, 2022 at 02:40:30PM +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_epp_perf to enable the EPP function firstly.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>  drivers/acpi/cppc_acpi.c | 76 +++++++++++++++++++++++++++++++++++++---
>  include/acpi/cppc_acpi.h | 12 +++++++
>  2 files changed, 83 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 093675b1a1ff..81081eb899ea 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;
> -

Do you have any specific reason to move this piece out of if-condition?

>  		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;
>  }
>  
>  /**
> @@ -1153,6 +1152,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
>  	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
>  }
>  
> +/**
> + * cppc_get_epp_perf - Get the epp register value.
> + * @cpunum: CPU from which to get epp preference value.
> + * @epp_perf: Return address.
> + *
> + * Return: 0 for success, -EIO otherwise.
> + */
> +int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
> +{
> +	return cppc_get_perf(cpunum, ENERGY_PERF, epp_perf);
> +}
> +EXPORT_SYMBOL_GPL(cppc_get_epp_perf);
> +

This function is enough to get the epp value.

Thanks,
Ray

>  /**
>   * cppc_get_perf_caps - Get a CPU's performance capabilities.
>   * @cpunum: CPU from which to get capabilities info.
> @@ -1365,6 +1377,60 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
>  }
>  EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
>  
> +/*
> + * 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..6b487a5bd638 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_perf(int cpunum, u64 *epp_perf);
> +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_perf(int cpunum, u64 *epp_perf)
> +{
> +	return -ENOTSUPP;
> +}
>  #endif /* !CONFIG_ACPI_CPPC_LIB */
>  
>  #endif /* _CPPC_ACPI_H*/
> -- 
> 2.34.1
>

[AMD Official Use Only - General]



> -----Original Message-----
> From: Huang, Ray <Ray.Huang@amd.com>
> Sent: Friday, December 23, 2022 10:16 AM
> To: Yuan, Perry <Perry.Yuan@amd.com>
> Cc: rafael.j.wysocki@intel.com; Limonciello, Mario
> <Mario.Limonciello@amd.com>; 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-kernel@vger.kernel.org
> Subject: Re: [PATCH v8 01/13] ACPI: CPPC: Add AMD pstate energy
> performance preference cppc control
> 
> On Mon, Dec 19, 2022 at 02:40:30PM +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_epp_perf to enable the EPP function firstly.
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> > ---
> >  drivers/acpi/cppc_acpi.c | 76
> > +++++++++++++++++++++++++++++++++++++---
> >  include/acpi/cppc_acpi.h | 12 +++++++
> >  2 files changed, 83 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index
> > 093675b1a1ff..81081eb899ea 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;
> > -
> 
> Do you have any specific reason to move this piece out of if-condition?

Move the declaration ahead of the If conditions like other functions did.
It looks more reasonable and no functions impact. 

Perry. 

> 
> >  		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;
> >  }
> >
> >  /**
> > @@ -1153,6 +1152,19 @@ int cppc_get_nominal_perf(int cpunum, u64
> *nominal_perf)
> >  	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);  }
> >
> > +/**
> > + * cppc_get_epp_perf - Get the epp register value.
> > + * @cpunum: CPU from which to get epp preference value.
> > + * @epp_perf: Return address.
> > + *
> > + * Return: 0 for success, -EIO otherwise.
> > + */
> > +int cppc_get_epp_perf(int cpunum, u64 *epp_perf) {
> > +	return cppc_get_perf(cpunum, ENERGY_PERF, epp_perf); }
> > +EXPORT_SYMBOL_GPL(cppc_get_epp_perf);
> > +
> 
> This function is enough to get the epp value.
> 
> Thanks,
> Ray
> 
> >  /**
> >   * cppc_get_perf_caps - Get a CPU's performance capabilities.
> >   * @cpunum: CPU from which to get capabilities info.
> > @@ -1365,6 +1377,60 @@ int cppc_get_perf_ctrs(int cpunum, struct
> > cppc_perf_fb_ctrs *perf_fb_ctrs)  }
> > EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
> >
> > +/*
> > + * 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..6b487a5bd638 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_perf(int cpunum, u64 *epp_perf); 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_perf(int cpunum, u64 *epp_perf) {
> > +	return -ENOTSUPP;
> > +}
> >  #endif /* !CONFIG_ACPI_CPPC_LIB */
> >
> >  #endif /* _CPPC_ACPI_H*/
> > --
> > 2.34.1
> >

On Fri, Dec 23, 2022 at 11:19:57AM +0800, Yuan, Perry wrote:
> [AMD Official Use Only - General]
> 
> 
> 
> > -----Original Message-----
> > From: Huang, Ray <Ray.Huang@amd.com>
> > Sent: Friday, December 23, 2022 10:16 AM
> > To: Yuan, Perry <Perry.Yuan@amd.com>
> > Cc: rafael.j.wysocki@intel.com; Limonciello, Mario
> > <Mario.Limonciello@amd.com>; 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-kernel@vger.kernel.org
> > Subject: Re: [PATCH v8 01/13] ACPI: CPPC: Add AMD pstate energy
> > performance preference cppc control
> > 
> > On Mon, Dec 19, 2022 at 02:40:30PM +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_epp_perf to enable the EPP function firstly.
> > >
> > > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> > > ---
> > >  drivers/acpi/cppc_acpi.c | 76
> > > +++++++++++++++++++++++++++++++++++++---
> > >  include/acpi/cppc_acpi.h | 12 +++++++
> > >  2 files changed, 83 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index
> > > 093675b1a1ff..81081eb899ea 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;
> > > -
> > 
> > Do you have any specific reason to move this piece out of if-condition?
> 
> Move the declaration ahead of the If conditions like other functions did.
> It looks more reasonable and no functions impact. 
>

If one platform doesn't have any CPC registers, it even won't need define
these variables like pcc_ss_id, pcc_ss_data, and it will save more time.

Thanks,
Ray

[AMD Official Use Only - General]



> -----Original Message-----
> From: Huang, Ray <Ray.Huang@amd.com>
> Sent: Friday, December 23, 2022 5:06 PM
> To: Yuan, Perry <Perry.Yuan@amd.com>
> Cc: rafael.j.wysocki@intel.com; Limonciello, Mario
> <Mario.Limonciello@amd.com>; 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-kernel@vger.kernel.org
> Subject: Re: [PATCH v8 01/13] ACPI: CPPC: Add AMD pstate energy
> performance preference cppc control
> 
> On Fri, Dec 23, 2022 at 11:19:57AM +0800, Yuan, Perry wrote:
> > [AMD Official Use Only - General]
> >
> >
> >
> > > -----Original Message-----
> > > From: Huang, Ray <Ray.Huang@amd.com>
> > > Sent: Friday, December 23, 2022 10:16 AM
> > > To: Yuan, Perry <Perry.Yuan@amd.com>
> > > Cc: rafael.j.wysocki@intel.com; Limonciello, Mario
> > > <Mario.Limonciello@amd.com>; 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-kernel@vger.kernel.org
> > > Subject: Re: [PATCH v8 01/13] ACPI: CPPC: Add AMD pstate energy
> > > performance preference cppc control
> > >
> > > On Mon, Dec 19, 2022 at 02:40:30PM +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_epp_perf to enable the EPP
> function firstly.
> > > >
> > > > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> > > > ---
> > > >  drivers/acpi/cppc_acpi.c | 76
> > > > +++++++++++++++++++++++++++++++++++++---
> > > >  include/acpi/cppc_acpi.h | 12 +++++++
> > > >  2 files changed, 83 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> > > > index 093675b1a1ff..81081eb899ea 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;
> > > > -
> > >
> > > Do you have any specific reason to move this piece out of if-condition?
> >
> > Move the declaration ahead of the If conditions like other functions did.
> > It looks more reasonable and no functions impact.
> >
> 
> If one platform doesn't have any CPC registers, it even won't need define
> these variables like pcc_ss_id, pcc_ss_data, and it will save more time.
> 
> Thanks,
> Ray

Make sense , get it fixed in V9 

For this patch there's a few small nits you should fix for v9.
With those fixed:

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

On 12/19/2022 00:40, Perry Yuan 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

Missing a period here at end of the sentence.

> 
> 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_epp_perf to enable the EPP function firstly.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>   drivers/acpi/cppc_acpi.c | 76 +++++++++++++++++++++++++++++++++++++---
>   include/acpi/cppc_acpi.h | 12 +++++++
>   2 files changed, 83 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 093675b1a1ff..81081eb899ea 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;
>   }
>   
>   /**
> @@ -1153,6 +1152,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
>   	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
>   }
>   
> +/**
> + * cppc_get_epp_perf - Get the epp register value.
> + * @cpunum: CPU from which to get epp preference value.
> + * @epp_perf: Return address.
> + *
> + * Return: 0 for success, -EIO otherwise.
> + */
> +int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
> +{
> +	return cppc_get_perf(cpunum, ENERGY_PERF, epp_perf);
> +}
> +EXPORT_SYMBOL_GPL(cppc_get_epp_perf);
> +
>   /**
>    * cppc_get_perf_caps - Get a CPU's performance capabilities.
>    * @cpunum: CPU from which to get capabilities info.
> @@ -1365,6 +1377,60 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
>   }
>   EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
>   
> +/*
> + * 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;

AFAICT, you don't actually ever return -EINVAL in this function.
I think you should just avoid initializing this variable.

> +
> +	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");

Would it perhaps be useful to note the cpu # for this message?

> +			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..6b487a5bd638 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_perf(int cpunum, u64 *epp_perf);
> +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_perf(int cpunum, u64 *epp_perf)
> +{
> +	return -ENOTSUPP;
> +}
>   #endif /* !CONFIG_ACPI_CPPC_LIB */
>   
>   #endif /* _CPPC_ACPI_H*/