Re: [PATCH v3 2/2] ACPI: CPPC: Add ospm_nominal_perf support
From: Pierre Gondois
Date: Thu May 21 2026 - 13:09:58 EST
Hello Sumit,
I copy-pasted and attached a complementary patch just to show
what I meant by caching the ospm_nominal_perf value at driver
init/exit.
This should also allow to handle the cases where a user tries
to store a new value for a policy with multiple CPUs,
one of the CPUs and we need to rollback.
I think another issue that should be solved is that:
- we don't the value of ospm_nominal_perf when loading the driver
- we leave the register in an unknown state if we unload/reload
the driver.
Note:
IMO caching values like in the patch would also benefit to the
auto_sel register.
------
If you think the patch helps, feel free to take it. Otherwise
please let me know the issues it would raise.
Regards,
Pierre
On 5/14/26 21:48, Sumit Gupta wrote:
Expose the OSPM Nominal Performance register (ACPI 6.6, Section
8.4.6.1.2.6), which conveys the desired nominal performance level
at which the platform may run. Unlike the existing read-only
Nominal Performance register, it is writable and lets OSPM
request a lower nominal level than the platform-reported nominal.
The platform classifies performance above this level as boosted
and below as throttled for its power/thermal decisions.
It is exposed as a per-policy cpufreq sysfs attribute in kHz, to
match the cpufreq sysfs unit convention:
/sys/devices/system/cpu/cpufreq/policyN/ospm_nominal_freq
The attribute is documented in
Documentation/ABI/testing/sysfs-devices-system-cpu.
Writes are converted to perf via cppc_khz_to_perf(), validated
against [Lowest Performance, Nominal Performance], and applied to
every CPU in policy->cpus.
The register is write-only; the kernel caches the last written
value in struct cppc_cpudata for sysfs readback (returns 0 until
userspace writes a value).
Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
---
.../ABI/testing/sysfs-devices-system-cpu | 17 ++++++++
drivers/acpi/cppc_acpi.c | 35 ++++++++++++++++
drivers/cpufreq/cppc_cpufreq.c | 40 +++++++++++++++++++
include/acpi/cppc_acpi.h | 7 ++++
4 files changed, 99 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 82d10d556cc8..ac1bf1b89ac4 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -346,6 +346,23 @@ Description: Performance Limited
This file is only present if the cppc-cpufreq driver is in use.
+What: /sys/devices/system/cpu/cpuX/cpufreq/ospm_nominal_freq
+Date: May 2026
+Contact: linux-pm@xxxxxxxxxxxxxxx
+Description: OSPM Nominal Performance (kHz)
+
+ OSPM uses this attribute to request a nominal performance
+ level lower than the platform-reported nominal. The
+ platform treats performance above this level as boost
+ and below as throttle for power and thermal decisions.
+
+ Read returns the last written value in kHz, or 0 if no
+ value has been written. Write a kHz value in the range
+ [lowest_freq, nominal_freq].
+
+ This file is only present if the cppc-cpufreq driver is
+ in use.
+
What: /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
Date: August 2008
KernelVersion: 2.6.27
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index c76cfafa3589..ad6ece16c30d 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1682,6 +1682,41 @@ int cppc_set_epp(int cpu, u64 epp_val)
}
EXPORT_SYMBOL_GPL(cppc_set_epp);
+/**
+ * cppc_set_ospm_nominal_perf() - Write OSPM Nominal Performance register.
+ * @cpu: CPU on which to write register.
+ * @ospm_nominal_perf: Value to write to the OSPM Nominal Performance register.
+ *
+ * OSPM Nominal Performance conveys the desired nominal performance level
+ * at which the platform may run. Per ACPI 6.6, s8.4.6.1.2.6, the value
+ * must lie within [Lowest Performance, Nominal Performance] and may be
+ * set independently of Minimum, Maximum and Desired performance.
+ *
+ * Return: 0 on success or negative error code.
+ */
+int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf)
+{
+ struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
+ struct cppc_perf_caps caps;
+ int ret;
+
+ if (!cpc_desc) {
+ pr_debug("No CPC descriptor for CPU:%d\n", cpu);
+ return -ENODEV;
+ }
+
+ ret = cppc_get_perf_caps(cpu, &caps);
+ if (ret)
+ return ret;
+
+ if (ospm_nominal_perf < caps.lowest_perf ||
+ ospm_nominal_perf > caps.nominal_perf)
+ return -EINVAL;
+
+ return cppc_set_reg_val(cpu, OSPM_NOMINAL_PERF, ospm_nominal_perf);
+}
+EXPORT_SYMBOL_GPL(cppc_set_ospm_nominal_perf);
+
/**
* cppc_get_auto_act_window() - Read autonomous activity window register.
* @cpu: CPU from which to read register.
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 7e7f9dfb7a24..6379b7ceee34 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -985,11 +985,50 @@ store_energy_performance_preference_val(struct cpufreq_policy *policy,
CPPC_CPUFREQ_ATTR_RW_U64(perf_limited, cppc_get_perf_limited,
cppc_set_perf_limited)
+static ssize_t show_ospm_nominal_freq(struct cpufreq_policy *policy, char *buf)
+{
+ struct cppc_cpudata *cpu_data = policy->driver_data;
+ unsigned int freq_khz;
+
+ if (!cpu_data->ospm_nominal_perf)
+ return sysfs_emit(buf, "0\n");
+
+ freq_khz = cppc_perf_to_khz(&cpu_data->perf_caps,
+ cpu_data->ospm_nominal_perf);
+ return sysfs_emit(buf, "%u\n", freq_khz);
+}
+
+static ssize_t store_ospm_nominal_freq(struct cpufreq_policy *policy,
+ const char *buf, size_t count)
+{
+ struct cppc_cpudata *cpu_data = policy->driver_data;
+ unsigned int sib;
+ u64 freq_khz;
+ u32 perf;
+ int ret;
+
+ ret = kstrtou64(buf, 0, &freq_khz);
+ if (ret)
+ return ret;
+
+ perf = cppc_khz_to_perf(&cpu_data->perf_caps, freq_khz);
+
+ for_each_cpu(sib, policy->cpus) {
+ ret = cppc_set_ospm_nominal_perf(sib, perf);
+ if (ret)
+ return ret;
+ }
+
+ cpu_data->ospm_nominal_perf = perf;
+ return count;
+}
+
cpufreq_freq_attr_ro(freqdomain_cpus);
cpufreq_freq_attr_rw(auto_select);
cpufreq_freq_attr_rw(auto_act_window);
cpufreq_freq_attr_rw(energy_performance_preference_val);
cpufreq_freq_attr_rw(perf_limited);
+cpufreq_freq_attr_rw(ospm_nominal_freq);
static struct freq_attr *cppc_cpufreq_attr[] = {
&freqdomain_cpus,
@@ -997,6 +1036,7 @@ static struct freq_attr *cppc_cpufreq_attr[] = {
&auto_act_window,
&energy_performance_preference_val,
&perf_limited,
+ &ospm_nominal_freq,
NULL,
};
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 8693890a7275..0b1dcdbea10a 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -153,6 +153,8 @@ struct cppc_cpudata {
struct cppc_perf_fb_ctrs perf_fb_ctrs;
unsigned int shared_type;
cpumask_var_t shared_cpu_map;
+ /* Cached OSPM Nominal Performance value (write-only register). */
+ u32 ospm_nominal_perf;
};
#ifdef CONFIG_ACPI_CPPC_LIB
@@ -180,6 +182,7 @@ 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);
extern int cppc_set_epp(int cpu, u64 epp_val);
+extern int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf);
extern int cppc_get_auto_act_window(int cpu, u64 *auto_act_window);
extern int cppc_set_auto_act_window(int cpu, u64 auto_act_window);
extern int cppc_get_auto_sel(int cpu, bool *enable);
@@ -266,6 +269,10 @@ static inline int cppc_set_epp(int cpu, u64 epp_val)
{
return -EOPNOTSUPP;
}
+static inline int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf)
+{
+ return -EOPNOTSUPP;
+}
static inline int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
{
return -EOPNOTSUPP;
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index ac1bf1b89ac4d..f3d357917242a 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -356,9 +356,7 @@Description: OSPM Nominal Performance (kHz)
platform treats performance above this level as boost
and below as throttle for power and thermal decisions.
- Read returns the last written value in kHz, or 0 if no
- value has been written. Write a kHz value in the range
- [lowest_freq, nominal_freq].
+Values are in kHz and in the range [lowest_freq, nominal_freq].
This file is only present if the cppc-cpufreq driver is
in use.
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 97218c4ac162b..01542184e69b2 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1717,6 +1717,19 @@int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf)
}
EXPORT_SYMBOL_GPL(cppc_set_ospm_nominal_perf);
+/**
+ * cppc_get_ospm_nominal_perf() - Read OSPM Nominal Performance register.
+ * @cpu: CPU from which to read register.
+ * @ospm_nominal_perf: Pointer to store the OSPM Nominal Performance value.
+ *
+ * Return: 0 on success or negative error code.
+ */
+int cppc_get_ospm_nominal_perf(int cpu, u64 *ospm_nominal_perf)
+{
+return cppc_get_reg_val(cpu, OSPM_NOMINAL_PERF, ospm_nominal_perf);
+}
+EXPORT_SYMBOL_GPL(cppc_get_ospm_nominal_perf);
+
/**
* cppc_get_auto_act_window() - Read autonomous activity window register.
* @cpu: CPU from which to read register.
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 6379b7ceee347..1a51017a81630 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -28,6 +28,9 @@
static struct cpufreq_driver cppc_cpufreq_driver;
+/* Values at driver init. */
+static u64 scratch_ospm_nominal_perf[NR_CPUS];
+
#ifdef CONFIG_ACPI_CPPC_CPUFREQ_FIE
static enum {
FIE_UNSET = -1,
@@ -642,7 +645,7 @@static void cppc_cpufreq_put_cpu_data(struct cpufreq_policy *policy)
static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
- unsigned int cpu = policy->cpu;
+unsigned int sib, cpu = policy->cpu;
struct cppc_cpudata *cpu_data;
struct cppc_perf_caps *caps;
int ret;
@@ -704,6 +707,34 @@static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
if (caps->highest_perf > caps->nominal_perf)
policy->boost_supported = true;
+/*
+ * CPUs are expected to have:
+ * ospm_nominal_perf = nominal_perf
+ * at policy init.
+ */
+cpu_data->ospm_nominal_perf = caps->nominal_perf;
+
+for_each_cpu(sib, policy->cpus) {
+u64 ospm_nominal_perf;
+
+ret = cppc_get_ospm_nominal_perf(sib, &ospm_nominal_perf);
+if (ret == -EOPNOTSUPP) {
+continue;
+} else if (ret) {
+pr_err("CPU%d: Could not read ospm_nominal_perf value\n",
+sib);
+goto out;
+}
+
+if (ospm_nominal_perf != caps->nominal_perf) {
+pr_err("Incoherent ospm_nominal_perf values: "
+"scratch_value=%llu expected_value=%u\n",
+scratch_ospm_nominal_perf[sib],
+caps->nominal_perf);
+goto out;
+}
+}
+
/* Set policy->cur to max now. The governors will adjust later. */
policy->cur = cppc_perf_to_khz(caps, caps->highest_perf);
cpu_data->perf_ctrls.desired_perf = caps->highest_perf;
@@ -727,9 +758,17 @@static void cppc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
struct cppc_perf_caps *caps = &cpu_data->perf_caps;
- unsigned int cpu = policy->cpu;
+unsigned int sib, cpu = policy->cpu;
int ret;
+/*
+ * CPUs are expected to have:
+ * ospm_nominal_perf = nominal_perf
+ * at policy init, so come back to that state.
+ */
+for_each_cpu(sib, policy->cpus)
+cppc_set_ospm_nominal_perf(sib, caps->nominal_perf);
+
cppc_cpufreq_cpu_fie_exit(policy);
cpu_data->perf_ctrls.desired_perf = caps->lowest_perf;
@@ -989,9 +1028,20 @@static ssize_t show_ospm_nominal_freq(struct cpufreq_policy *policy, char *buf)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
unsigned int freq_khz;
+u64 perf;
+int ret;
+
+ret = cppc_get_ospm_nominal_perf(policy->cpu, &perf);
+if (ret == -EOPNOTSUPP)
+return sysfs_emit(buf, "<unsupported>\n");
+if (ret)
+return ret;
- if (!cpu_data->ospm_nominal_perf)
- return sysfs_emit(buf, "0\n");
+if (perf != cpu_data->ospm_nominal_perf) {
+pr_warn("ospm_nominal_freq value is not coherent: "
+"register=%llu scratch_value=%u\n",
+perf, cpu_data->ospm_nominal_perf);
+}
freq_khz = cppc_perf_to_khz(&cpu_data->perf_caps,
cpu_data->ospm_nominal_perf);
@@ -1002,7 +1052,7 @@static ssize_t store_ospm_nominal_freq(struct cpufreq_policy *policy,
const char *buf, size_t count)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
- unsigned int sib;
+unsigned int sib, failing_cpu;
u64 freq_khz;
u32 perf;
int ret;
@@ -1015,12 +1065,23 @@static ssize_t store_ospm_nominal_freq(struct cpufreq_policy *policy,
for_each_cpu(sib, policy->cpus) {
ret = cppc_set_ospm_nominal_perf(sib, perf);
- if (ret)
- return ret;
+if (ret) {
+failing_cpu = sib;
+goto error;
+}
}
cpu_data->ospm_nominal_perf = perf;
return count;
+
+error:
+for_each_cpu(sib, policy->cpus) {
+if (sib == failing_cpu)
+break;
+cppc_set_ospm_nominal_perf(sib, cpu_data->ospm_nominal_perf);
+}
+
+return ret;
}
cpufreq_freq_attr_ro(freqdomain_cpus);
@@ -1053,6 +1114,64 @@static struct cpufreq_driver cppc_cpufreq_driver = {
.name = "cppc_cpufreq",
};
+static void __exit cppc_cpufreq_ospm_nominal_perf_exit(void)
+{
+int cpu;
+
+for_each_present_cpu(cpu) {
+if (scratch_ospm_nominal_perf[cpu] == U64_MAX)
+continue;
+
+/* Reset ospm_nominal_perf to the value present at init. */
+cppc_set_ospm_nominal_perf(cpu, scratch_ospm_nominal_perf[cpu]);
+}
+}
+
+static int __init cppc_cpufreq_ospm_nominal_perf_init(void)
+{
+int ret, cpu;
+
+ret = 0;
+
+for_each_present_cpu(cpu) {
+u64 nominal_perf;
+
+/*
+ * If one CPU failed, scratch_ospm_nominal_perf still needs
+ * to be initialized.
+ */
+if (ret) {
+scratch_ospm_nominal_perf[cpu] = U64_MAX;
+continue;
+}
+
+ret = cppc_get_ospm_nominal_perf(cpu, &scratch_ospm_nominal_perf[cpu]);
+if (ret) {
+if (ret == -EOPNOTSUPP) {
+/* Valid reason to fail. Continue to iterate. */
+ret = 0;
+}
+
+scratch_ospm_nominal_perf[cpu] = U64_MAX;
+continue;
+}
+
+/* Set ospm_nominal_perf to nominal_perf before policy init. */
+ret = cppc_get_nominal_perf(cpu, &nominal_perf);
+if (ret)
+continue;
+
+ret = cppc_set_ospm_nominal_perf(cpu, nominal_perf);
+if (ret)
+continue;
+}
+
+if (ret)
+cppc_cpufreq_ospm_nominal_perf_exit();
+
+return ret;
+}
+
static int __init cppc_cpufreq_init(void)
{
int ret;
@@ -1063,9 +1182,17 @@static int __init cppc_cpufreq_init(void)
cppc_freq_invariance_init();
populate_efficiency_class();
+ret = cppc_cpufreq_ospm_nominal_perf_init();
+if (ret) {
+cppc_freq_invariance_exit();
+return ret;
+}
+
ret = cpufreq_register_driver(&cppc_cpufreq_driver);
- if (ret)
+if (ret) {
+cppc_cpufreq_ospm_nominal_perf_exit();
cppc_freq_invariance_exit();
+}
return ret;
}
@@ -1074,6 +1201,7 @@static void __exit cppc_cpufreq_exit(void)
{
cpufreq_unregister_driver(&cppc_cpufreq_driver);
cppc_freq_invariance_exit();
+cppc_cpufreq_ospm_nominal_perf_exit();
}
module_exit(cppc_cpufreq_exit);
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 0b1dcdbea10a2..07e6598fa837a 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -183,6 +183,7 @@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);
extern int cppc_set_epp(int cpu, u64 epp_val);
extern int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf);
+extern int cppc_get_ospm_nominal_perf(int cpu, u64 *ospm_nominal_perf);
extern int cppc_get_auto_act_window(int cpu, u64 *auto_act_window);
extern int cppc_set_auto_act_window(int cpu, u64 auto_act_window);
extern int cppc_get_auto_sel(int cpu, bool *enable);
@@ -273,6 +274,10 @@static inline int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf)
{
return -EOPNOTSUPP;
}
+static inline int cppc_get_ospm_nominal_perf(int cpu, u64 *ospm_nominal_perf)
+{
+return -EOPNOTSUPP;
+}
static inline int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
{
return -EOPNOTSUPP;
From 28a1fd8e94f860a3bbf135779fa399621e9355ad Mon Sep 17 00:00:00 2001
From: Pierre Gondois <pierre.gondois@xxxxxxx>
Date: Thu, 21 May 2026 14:53:46 +0200
Subject: [PATCH] ACPI: CPPC: Add ospm_nominal_perf support additional changes
Complementary modifications to:
- "ACPI: CPPC: Add ospm_nominal_perf support"
Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
---
.../ABI/testing/sysfs-devices-system-cpu | 4 +-
drivers/acpi/cppc_acpi.c | 13 ++
drivers/cpufreq/cppc_cpufreq.c | 144 +++++++++++++++++-
include/acpi/cppc_acpi.h | 5 +
4 files changed, 155 insertions(+), 11 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index ac1bf1b89ac4d..f3d357917242a 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -356,9 +356,7 @@ Description: OSPM Nominal Performance (kHz)
platform treats performance above this level as boost
and below as throttle for power and thermal decisions.
- Read returns the last written value in kHz, or 0 if no
- value has been written. Write a kHz value in the range
- [lowest_freq, nominal_freq].
+ Values are in kHz and in the range [lowest_freq, nominal_freq].
This file is only present if the cppc-cpufreq driver is
in use.
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 97218c4ac162b..01542184e69b2 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1717,6 +1717,19 @@ int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf)
}
EXPORT_SYMBOL_GPL(cppc_set_ospm_nominal_perf);
+/**
+ * cppc_get_ospm_nominal_perf() - Read OSPM Nominal Performance register.
+ * @cpu: CPU from which to read register.
+ * @ospm_nominal_perf: Pointer to store the OSPM Nominal Performance value.
+ *
+ * Return: 0 on success or negative error code.
+ */
+int cppc_get_ospm_nominal_perf(int cpu, u64 *ospm_nominal_perf)
+{
+ return cppc_get_reg_val(cpu, OSPM_NOMINAL_PERF, ospm_nominal_perf);
+}
+EXPORT_SYMBOL_GPL(cppc_get_ospm_nominal_perf);
+
/**
* cppc_get_auto_act_window() - Read autonomous activity window register.
* @cpu: CPU from which to read register.
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 6379b7ceee347..1a51017a81630 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -28,6 +28,9 @@
static struct cpufreq_driver cppc_cpufreq_driver;
+/* Values at driver init. */
+static u64 scratch_ospm_nominal_perf[NR_CPUS];
+
#ifdef CONFIG_ACPI_CPPC_CPUFREQ_FIE
static enum {
FIE_UNSET = -1,
@@ -642,7 +645,7 @@ static void cppc_cpufreq_put_cpu_data(struct cpufreq_policy *policy)
static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
- unsigned int cpu = policy->cpu;
+ unsigned int sib, cpu = policy->cpu;
struct cppc_cpudata *cpu_data;
struct cppc_perf_caps *caps;
int ret;
@@ -704,6 +707,34 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
if (caps->highest_perf > caps->nominal_perf)
policy->boost_supported = true;
+ /*
+ * CPUs are expected to have:
+ * ospm_nominal_perf = nominal_perf
+ * at policy init.
+ */
+ cpu_data->ospm_nominal_perf = caps->nominal_perf;
+
+ for_each_cpu(sib, policy->cpus) {
+ u64 ospm_nominal_perf;
+
+ ret = cppc_get_ospm_nominal_perf(sib, &ospm_nominal_perf);
+ if (ret == -EOPNOTSUPP) {
+ continue;
+ } else if (ret) {
+ pr_err("CPU%d: Could not read ospm_nominal_perf value\n",
+ sib);
+ goto out;
+ }
+
+ if (ospm_nominal_perf != caps->nominal_perf) {
+ pr_err("Incoherent ospm_nominal_perf values: "
+ "scratch_value=%llu expected_value=%u\n",
+ scratch_ospm_nominal_perf[sib],
+ caps->nominal_perf);
+ goto out;
+ }
+ }
+
/* Set policy->cur to max now. The governors will adjust later. */
policy->cur = cppc_perf_to_khz(caps, caps->highest_perf);
cpu_data->perf_ctrls.desired_perf = caps->highest_perf;
@@ -727,9 +758,17 @@ static void cppc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
struct cppc_perf_caps *caps = &cpu_data->perf_caps;
- unsigned int cpu = policy->cpu;
+ unsigned int sib, cpu = policy->cpu;
int ret;
+ /*
+ * CPUs are expected to have:
+ * ospm_nominal_perf = nominal_perf
+ * at policy init, so come back to that state.
+ */
+ for_each_cpu(sib, policy->cpus)
+ cppc_set_ospm_nominal_perf(sib, caps->nominal_perf);
+
cppc_cpufreq_cpu_fie_exit(policy);
cpu_data->perf_ctrls.desired_perf = caps->lowest_perf;
@@ -989,9 +1028,20 @@ static ssize_t show_ospm_nominal_freq(struct cpufreq_policy *policy, char *buf)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
unsigned int freq_khz;
+ u64 perf;
+ int ret;
+
+ ret = cppc_get_ospm_nominal_perf(policy->cpu, &perf);
+ if (ret == -EOPNOTSUPP)
+ return sysfs_emit(buf, "<unsupported>\n");
+ if (ret)
+ return ret;
- if (!cpu_data->ospm_nominal_perf)
- return sysfs_emit(buf, "0\n");
+ if (perf != cpu_data->ospm_nominal_perf) {
+ pr_warn("ospm_nominal_freq value is not coherent: "
+ "register=%llu scratch_value=%u\n",
+ perf, cpu_data->ospm_nominal_perf);
+ }
freq_khz = cppc_perf_to_khz(&cpu_data->perf_caps,
cpu_data->ospm_nominal_perf);
@@ -1002,7 +1052,7 @@ static ssize_t store_ospm_nominal_freq(struct cpufreq_policy *policy,
const char *buf, size_t count)
{
struct cppc_cpudata *cpu_data = policy->driver_data;
- unsigned int sib;
+ unsigned int sib, failing_cpu;
u64 freq_khz;
u32 perf;
int ret;
@@ -1015,12 +1065,23 @@ static ssize_t store_ospm_nominal_freq(struct cpufreq_policy *policy,
for_each_cpu(sib, policy->cpus) {
ret = cppc_set_ospm_nominal_perf(sib, perf);
- if (ret)
- return ret;
+ if (ret) {
+ failing_cpu = sib;
+ goto error;
+ }
}
cpu_data->ospm_nominal_perf = perf;
return count;
+
+error:
+ for_each_cpu(sib, policy->cpus) {
+ if (sib == failing_cpu)
+ break;
+ cppc_set_ospm_nominal_perf(sib, cpu_data->ospm_nominal_perf);
+ }
+
+ return ret;
}
cpufreq_freq_attr_ro(freqdomain_cpus);
@@ -1053,6 +1114,64 @@ static struct cpufreq_driver cppc_cpufreq_driver = {
.name = "cppc_cpufreq",
};
+static void __exit cppc_cpufreq_ospm_nominal_perf_exit(void)
+{
+ int cpu;
+
+ for_each_present_cpu(cpu) {
+ if (scratch_ospm_nominal_perf[cpu] == U64_MAX)
+ continue;
+
+ /* Reset ospm_nominal_perf to the value present at init. */
+ cppc_set_ospm_nominal_perf(cpu, scratch_ospm_nominal_perf[cpu]);
+ }
+}
+
+static int __init cppc_cpufreq_ospm_nominal_perf_init(void)
+{
+ int ret, cpu;
+
+ ret = 0;
+
+ for_each_present_cpu(cpu) {
+ u64 nominal_perf;
+
+ /*
+ * If one CPU failed, scratch_ospm_nominal_perf still needs
+ * to be initialized.
+ */
+ if (ret) {
+ scratch_ospm_nominal_perf[cpu] = U64_MAX;
+ continue;
+ }
+
+ ret = cppc_get_ospm_nominal_perf(cpu, &scratch_ospm_nominal_perf[cpu]);
+ if (ret) {
+ if (ret == -EOPNOTSUPP) {
+ /* Valid reason to fail. Continue to iterate. */
+ ret = 0;
+ }
+
+ scratch_ospm_nominal_perf[cpu] = U64_MAX;
+ continue;
+ }
+
+ /* Set ospm_nominal_perf to nominal_perf before policy init. */
+ ret = cppc_get_nominal_perf(cpu, &nominal_perf);
+ if (ret)
+ continue;
+
+ ret = cppc_set_ospm_nominal_perf(cpu, nominal_perf);
+ if (ret)
+ continue;
+ }
+
+ if (ret)
+ cppc_cpufreq_ospm_nominal_perf_exit();
+
+ return ret;
+}
+
static int __init cppc_cpufreq_init(void)
{
int ret;
@@ -1063,9 +1182,17 @@ static int __init cppc_cpufreq_init(void)
cppc_freq_invariance_init();
populate_efficiency_class();
+ ret = cppc_cpufreq_ospm_nominal_perf_init();
+ if (ret) {
+ cppc_freq_invariance_exit();
+ return ret;
+ }
+
ret = cpufreq_register_driver(&cppc_cpufreq_driver);
- if (ret)
+ if (ret) {
+ cppc_cpufreq_ospm_nominal_perf_exit();
cppc_freq_invariance_exit();
+ }
return ret;
}
@@ -1074,6 +1201,7 @@ static void __exit cppc_cpufreq_exit(void)
{
cpufreq_unregister_driver(&cppc_cpufreq_driver);
cppc_freq_invariance_exit();
+ cppc_cpufreq_ospm_nominal_perf_exit();
}
module_exit(cppc_cpufreq_exit);
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 0b1dcdbea10a2..07e6598fa837a 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -183,6 +183,7 @@ 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);
extern int cppc_set_epp(int cpu, u64 epp_val);
extern int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf);
+extern int cppc_get_ospm_nominal_perf(int cpu, u64 *ospm_nominal_perf);
extern int cppc_get_auto_act_window(int cpu, u64 *auto_act_window);
extern int cppc_set_auto_act_window(int cpu, u64 auto_act_window);
extern int cppc_get_auto_sel(int cpu, bool *enable);
@@ -273,6 +274,10 @@ static inline int cppc_set_ospm_nominal_perf(int cpu, u64 ospm_nominal_perf)
{
return -EOPNOTSUPP;
}
+static inline int cppc_get_ospm_nominal_perf(int cpu, u64 *ospm_nominal_perf)
+{
+ return -EOPNOTSUPP;
+}
static inline int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
{
return -EOPNOTSUPP;
--
2.43.0