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ACPI: CPPC: Add cppc_get_perf() API to read performance controls

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Add cppc_get_perf() function to read values of performance control
registers including desired_perf, min_perf, max_perf, energy_perf,
and auto_sel.

This provides a read interface to complement the existing
cppc_set_perf() write interface for performance control registers.

Note that auto_sel is read by cppc_get_perf() but not written by
cppc_set_perf() to avoid unintended mode changes during performance
updates. It can be updated with existing dedicated cppc_set_auto_sel()
API.

Use cppc_get_perf() in cppc_cpufreq_get_cpu_data() to initialize
perf_ctrls with current hardware register values during cpufreq
policy initialization.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Link: https://patch.msgid.link/20260206142658.72583-2-sumitg@nvidia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Sumit Gupta
2026-02-27 20:50:41 +01:00
committed by Rafael J. Wysocki
parent 6de23f81a5
commit 658fa7b1c4
3 changed files with 91 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/acpi/cppc_acpi.c
+80
View File
@@ -1738,6 +1738,86 @@ int cppc_set_enable(int cpu, bool enable)
}
EXPORT_SYMBOL_GPL(cppc_set_enable);
/**
* cppc_get_perf - Get a CPU's performance controls.
* @cpu: CPU for which to get performance controls.
* @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
*
* Return: 0 for success with perf_ctrls, -ERRNO otherwise.
*/
int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
{
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
struct cpc_register_resource *desired_perf_reg,
*min_perf_reg, *max_perf_reg,
*energy_perf_reg, *auto_sel_reg;
u64 desired_perf = 0, min = 0, max = 0, energy_perf = 0, auto_sel = 0;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
struct cppc_pcc_data *pcc_ss_data = NULL;
int ret = 0, regs_in_pcc = 0;
if (!cpc_desc) {
pr_debug("No CPC descriptor for CPU:%d\n", cpu);
return -ENODEV;
}
if (!perf_ctrls) {
pr_debug("Invalid perf_ctrls pointer\n");
return -EINVAL;
}
desired_perf_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
min_perf_reg = &cpc_desc->cpc_regs[MIN_PERF];
max_perf_reg = &cpc_desc->cpc_regs[MAX_PERF];
energy_perf_reg = &cpc_desc->cpc_regs[ENERGY_PERF];
auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
/* Are any of the regs PCC ?*/
if (CPC_IN_PCC(desired_perf_reg) || CPC_IN_PCC(min_perf_reg) ||
CPC_IN_PCC(max_perf_reg) || CPC_IN_PCC(energy_perf_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;
}
pcc_ss_data = pcc_data[pcc_ss_id];
regs_in_pcc = 1;
down_write(&pcc_ss_data->pcc_lock);
/* Ring doorbell once to update PCC subspace */
if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
ret = -EIO;
goto out_err;
}
}
/* Read optional elements if present */
if (CPC_SUPPORTED(max_perf_reg))
cpc_read(cpu, max_perf_reg, &max);
perf_ctrls->max_perf = max;
if (CPC_SUPPORTED(min_perf_reg))
cpc_read(cpu, min_perf_reg, &min);
perf_ctrls->min_perf = min;
if (CPC_SUPPORTED(desired_perf_reg))
cpc_read(cpu, desired_perf_reg, &desired_perf);
perf_ctrls->desired_perf = desired_perf;
if (CPC_SUPPORTED(energy_perf_reg))
cpc_read(cpu, energy_perf_reg, &energy_perf);
perf_ctrls->energy_perf = energy_perf;
if (CPC_SUPPORTED(auto_sel_reg))
cpc_read(cpu, auto_sel_reg, &auto_sel);
perf_ctrls->auto_sel = (bool)auto_sel;
out_err:
if (regs_in_pcc)
up_write(&pcc_ss_data->pcc_lock);
return ret;
}
EXPORT_SYMBOL_GPL(cppc_get_perf);
/**
* cppc_set_perf - Set a CPU's performance controls.
* @cpu: CPU for which to set performance controls.
drivers/cpufreq/cppc_cpufreq.c
+6
View File
@@ -594,6 +594,12 @@ static struct cppc_cpudata *cppc_cpufreq_get_cpu_data(unsigned int cpu)
goto free_mask;
}
ret = cppc_get_perf(cpu, &cpu_data->perf_ctrls);
if (ret) {
pr_debug("Err reading CPU%d perf ctrls: ret:%d\n", cpu, ret);
goto free_mask;
}
return cpu_data;
free_mask:
include/acpi/cppc_acpi.h
+5
View File
@@ -151,6 +151,7 @@ extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
extern int cppc_get_highest_perf(int cpunum, u64 *highest_perf);
extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
extern int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
extern int cppc_set_enable(int cpu, bool enable);
extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
@@ -193,6 +194,10 @@ static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_
{
return -EOPNOTSUPP;
}
static inline int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
{
return -EOPNOTSUPP;
}
static inline int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
{
return -EOPNOTSUPP;