ACPI: CPPC: Add AMD pstate energy performance preference cppc control

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.

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 0f17b1c..02d83c8 100644 (file)
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1154,6 +1154,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *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.
  * @perf_caps: ptr to cppc_perf_caps. See cppc_acpi.h
@@ -1365,6 +1378,60 @@ out_err:
 }
 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;
+
+       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 for CPU:%d\n", cpu);
+                       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 c561444..6b487a5 100644 (file)
--- 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*/