[Patch 1/5] ACPI: CPPC: add read perf ctrls api and rename few existing

Sumit Gupta
2025-02-11T10:38:10Z

Add new API cppc_get_perf_ctrls() to read the performance controls.
Rename the following existing API's for more clarity.
- cppc_set_perf() to cppc_set_perf_ctrls().
- cppc_get_perf_ctrs() to cppc_get_perf_fb_ctrs().
- cppc_get_perf_ctrs_sample() to cppc_get_perf_fb_ctrs_sample().

Also, remove redundant energy_perf field from 'struct cppc_perf_caps'.
It is also present in 'struct cppc_perf_ctrls' which is being used.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
---
drivers/acpi/cppc_acpi.c | 91 +++++++++++++++++++++++++++++-----
drivers/cpufreq/cppc_cpufreq.c | 26 +++++-----
include/acpi/cppc_acpi.h | 14 ++++--
3 files changed, 101 insertions(+), 30 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index f193e713825a..297e689f8214 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -59,7 +59,7 @@ struct cppc_pcc_data {
/*
* Lock to provide controlled access to the PCC channel.
*
- * For performance critical usecases(currently cppc_set_perf)
+ * For performance critical usecases(currently cppc_set_perf_ctrls)
* We need to take read_lock and check if channel belongs to OSPM
* before reading or writing to PCC subspace
* We need to take write_lock before transferring the channel
@@ -169,8 +169,8 @@ show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, guaranteed_perf);
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_freq);
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);

-show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
-show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
+show_cppc_data(cppc_get_perf_fb_ctrs, cppc_perf_fb_ctrs, reference_perf);
+show_cppc_data(cppc_get_perf_fb_ctrs, cppc_perf_fb_ctrs, wraparound_time);

/* Check for valid access_width, otherwise, fallback to using bit_width */
#define GET_BIT_WIDTH(reg) ((reg)->access_width ? (8 << ((reg)->access_width - 1)) : (reg)->bit_width)
@@ -189,7 +189,7 @@ static ssize_t show_feedback_ctrs(struct kobject *kobj,
struct cppc_perf_fb_ctrs fb_ctrs = {0};
int ret;

- ret = cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
+ ret = cppc_get_perf_fb_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
if (ret)
return ret;

@@ -1360,7 +1360,7 @@ EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
*
* CPPC has flexibility about how CPU performance counters are accessed.
* One of the choices is PCC regions, which can have a high access latency. This
- * routine allows callers of cppc_get_perf_ctrs() to know this ahead of time.
+ * routine allows callers of cppc_get_perf_fb_ctrs() to know this ahead of time.
*
* Return: true if any of the counters are in PCC regions, false otherwise
*/
@@ -1398,13 +1398,13 @@ bool cppc_perf_ctrs_in_pcc(void)
EXPORT_SYMBOL_GPL(cppc_perf_ctrs_in_pcc);

/**
- * cppc_get_perf_ctrs - Read a CPU's performance feedback counters.
+ * cppc_get_perf_fb_ctrs - Read a CPU's performance feedback counters.
* @cpunum: CPU from which to read counters.
* @perf_fb_ctrs: ptr to cppc_perf_fb_ctrs. See cppc_acpi.h
*
* Return: 0 for success with perf_fb_ctrs populated else -ERRNO.
*/
-int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
+int cppc_get_perf_fb_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
{
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
struct cpc_register_resource *delivered_reg, *reference_reg,
@@ -1475,7 +1475,7 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
up_write(&pcc_ss_data->pcc_lock);
return ret;
}
-EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
+EXPORT_SYMBOL_GPL(cppc_get_perf_fb_ctrs);

/*
* Set Energy Performance Preference Register value through
@@ -1674,15 +1674,82 @@ int cppc_set_enable(int cpu, bool enable)
return cpc_write(cpu, enable_reg, 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_ctrls(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;
+ u64 max, min, desired_perf, energy_perf;
+ 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;
+ }
+
+ 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];
+
+ /* 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)) {
+ if (pcc_ss_id < 0) {
+ pr_debug("Invalid pcc_ss_id\n");
+ 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;
+
+out_err:
+ if (regs_in_pcc)
+ up_write(&pcc_ss_data->pcc_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cppc_get_perf_ctrls);

/**
- * cppc_set_perf - Set a CPU's performance controls.
+ * cppc_set_perf_ctrls - Set a CPU's performance controls.
* @cpu: CPU for which to set performance controls.
* @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
*
* Return: 0 for success, -ERRNO otherwise.
*/
-int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
+int cppc_set_perf_ctrls(int cpu, struct cppc_perf_ctrls *perf_ctrls)
{
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
struct cpc_register_resource *desired_reg, *min_perf_reg, *max_perf_reg;
@@ -1746,7 +1813,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
/*
* This is Phase-II where we transfer the ownership of PCC to Platform
*
- * Short Summary: Basically if we think of a group of cppc_set_perf
+ * Short Summary: Basically if we think of a group of cppc_set_perf_ctrls
* requests that happened in short overlapping interval. The last CPU to
* come out of Phase-I will enter Phase-II and ring the doorbell.
*
@@ -1805,7 +1872,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
}
return ret;
}
-EXPORT_SYMBOL_GPL(cppc_set_perf);
+EXPORT_SYMBOL_GPL(cppc_set_perf_ctrls);

/**
* cppc_get_transition_latency - returns frequency transition latency in ns
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index b3d74f9adcf0..17c49653a3c4 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -90,7 +90,7 @@ static void cppc_scale_freq_workfn(struct kthread_work *work)
cppc_fi = container_of(work, struct cppc_freq_invariance, work);
cpu_data = cppc_fi->cpu_data;

- if (cppc_get_perf_ctrs(cppc_fi->cpu, &fb_ctrs)) {
+ if (cppc_get_perf_fb_ctrs(cppc_fi->cpu, &fb_ctrs)) {
pr_warn("%s: failed to read perf counters\n", __func__);
return;
}
@@ -125,7 +125,7 @@ static void cppc_scale_freq_tick(void)
struct cppc_freq_invariance *cppc_fi = &per_cpu(cppc_freq_inv, smp_processor_id());

/*
- * cppc_get_perf_ctrs() can potentially sleep, call that from the right
+ * cppc_get_perf_fb_ctrs() can potentially sleep, call that from the right
* context.
*/
irq_work_queue(&cppc_fi->irq_work);
@@ -151,7 +151,7 @@ static void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy)
kthread_init_work(&cppc_fi->work, cppc_scale_freq_workfn);
init_irq_work(&cppc_fi->irq_work, cppc_irq_work);

- ret = cppc_get_perf_ctrs(cpu, &cppc_fi->prev_perf_fb_ctrs);
+ ret = cppc_get_perf_fb_ctrs(cpu, &cppc_fi->prev_perf_fb_ctrs);
if (ret) {
pr_warn("%s: failed to read perf counters for cpu:%d: %d\n",
__func__, cpu, ret);
@@ -281,7 +281,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
freqs.new = target_freq;

cpufreq_freq_transition_begin(policy, &freqs);
- ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
+ ret = cppc_set_perf_ctrls(cpu, &cpu_data->perf_ctrls);
cpufreq_freq_transition_end(policy, &freqs, ret != 0);

if (ret)
@@ -301,7 +301,7 @@ static unsigned int cppc_cpufreq_fast_switch(struct cpufreq_policy *policy,

desired_perf = cppc_khz_to_perf(&cpu_data->perf_caps, target_freq);
cpu_data->perf_ctrls.desired_perf = desired_perf;
- ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
+ ret = cppc_set_perf_ctrls(cpu, &cpu_data->perf_ctrls);

if (ret) {
pr_debug("Failed to set target on CPU:%d. ret:%d\n",
@@ -657,7 +657,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
policy->cur = cppc_perf_to_khz(caps, caps->highest_perf);
cpu_data->perf_ctrls.desired_perf = caps->highest_perf;

- ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
+ ret = cppc_set_perf_ctrls(cpu, &cpu_data->perf_ctrls);
if (ret) {
pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
caps->highest_perf, cpu, ret);
@@ -683,7 +683,7 @@ static void cppc_cpufreq_cpu_exit(struct cpufreq_policy *policy)

cpu_data->perf_ctrls.desired_perf = caps->lowest_perf;

- ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
+ ret = cppc_set_perf_ctrls(cpu, &cpu_data->perf_ctrls);
if (ret)
pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
caps->lowest_perf, cpu, ret);
@@ -723,19 +723,19 @@ static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data,
return (reference_perf * delta_delivered) / delta_reference;
}

-static int cppc_get_perf_ctrs_sample(int cpu,
- struct cppc_perf_fb_ctrs *fb_ctrs_t0,
- struct cppc_perf_fb_ctrs *fb_ctrs_t1)
+static int cppc_get_perf_fb_ctrs_sample(int cpu,
+ struct cppc_perf_fb_ctrs *fb_ctrs_t0,
+ struct cppc_perf_fb_ctrs *fb_ctrs_t1)
{
int ret;

- ret = cppc_get_perf_ctrs(cpu, fb_ctrs_t0);
+ ret = cppc_get_perf_fb_ctrs(cpu, fb_ctrs_t0);
if (ret)
return ret;

udelay(2); /* 2usec delay between sampling */

- return cppc_get_perf_ctrs(cpu, fb_ctrs_t1);
+ return cppc_get_perf_fb_ctrs(cpu, fb_ctrs_t1);
}

static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
@@ -753,7 +753,7 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)

cpufreq_cpu_put(policy);

- ret = cppc_get_perf_ctrs_sample(cpu, &fb_ctrs_t0, &fb_ctrs_t1);
+ ret = cppc_get_perf_fb_ctrs_sample(cpu, &fb_ctrs_t0, &fb_ctrs_t1);
if (ret) {
if (ret == -EFAULT)
/* Any of the associated CPPC regs is 0. */
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 62d368bcd9ec..31f4fd288b65 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -110,7 +110,6 @@ struct cppc_perf_caps {
u32 lowest_nonlinear_perf;
u32 lowest_freq;
u32 nominal_freq;
- u32 energy_perf;
bool auto_sel;
};

@@ -142,8 +141,9 @@ struct cppc_cpudata {
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_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
+extern int cppc_get_perf_fb_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
+extern int cppc_get_perf_ctrls(int cpu, struct cppc_perf_ctrls *perf_ctrls);
+extern int cppc_set_perf_ctrls(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);
extern bool cppc_perf_ctrs_in_pcc(void);
@@ -177,11 +177,15 @@ static inline int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
{
return -EOPNOTSUPP;
}
-static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
+static inline int cppc_get_perf_fb_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
+{
+ return -EOPNOTSUPP;
+}
+static inline int cppc_get_perf_ctrls(int cpu, struct cppc_perf_ctrls *perf_ctrls)
{
return -EOPNOTSUPP;
}
-static inline int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
+static inline int cppc_set_perf_ctrls(int cpu, struct cppc_perf_ctrls *perf_ctrls)
{
return -EOPNOTSUPP;
}
--
2.25.1