[PATCH v10 01/12] ACPI: CPPC: Add AMD pstate energy performance preference cppc control

Perry Yuan
2023-01-06T06:14:50Z

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.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
---
drivers/acpi/cppc_acpi.c | 67 ++++++++++++++++++++++++++++++++++++++++
include/acpi/cppc_acpi.h | 12 +++++++
2 files changed, 79 insertions(+)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 093675b1a1ff..0ce6c55a76ca 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1153,6 +1153,19 @@ 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 +1378,60 @@ 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;
+
+ 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 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