diff --git a/Documentation/cpu-freq/intel-pstate.txt b/Documentation/cpu-freq/intel-pstate.txt
index 1953994ef5e6bfe4b5897bdd427b087f361c63e0..3fdcdfd968ba1237ef61856c51463d123b9321a1 100644
--- a/Documentation/cpu-freq/intel-pstate.txt
+++ b/Documentation/cpu-freq/intel-pstate.txt
@@ -85,6 +85,21 @@ Sysfs will show :
Refer to "Intel® 64 and IA-32 Architectures Software Developer’s Manual
Volume 3: System Programming Guide" to understand ratios.
+There is one more sysfs attribute in /sys/devices/system/cpu/intel_pstate/
+that can be used for controlling the operation mode of the driver:
+
+ status: Three settings are possible:
+ "off" - The driver is not in use at this time.
+ "active" - The driver works as a P-state governor (default).
+ "passive" - The driver works as a regular cpufreq one and collaborates
+ with the generic cpufreq governors (it sets P-states as
+ requested by those governors).
+ The current setting is returned by reads from this attribute. Writing one
+ of the above strings to it changes the operation mode as indicated by that
+ string, if possible. If HW-managed P-states (HWP) are enabled, it is not
+ possible to change the driver's operation mode and attempts to write to
+ this attribute will fail.
+
cpufreq sysfs for Intel P-State
Since this driver registers with cpufreq, cpufreq sysfs is also presented.
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 2d8a51733a51643e389e00c0b0a788f8109b6628..c783151b71e941d2696d3755c0bce1c5ca6f1226 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -541,7 +541,6 @@ static void intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)
acpi_processor_unregister_performance(policy->cpu);
}
-
#else
static inline void intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy)
{
@@ -1010,35 +1009,57 @@ static int pid_param_get(void *data, u64 *val)
}
DEFINE_SIMPLE_ATTRIBUTE(fops_pid_param, pid_param_get, pid_param_set, "%llu\n");
+static struct dentry *debugfs_parent;
+
struct pid_param {
char *name;
void *value;
+ struct dentry *dentry;
};
static struct pid_param pid_files[] = {
- {"sample_rate_ms", &pid_params.sample_rate_ms},
- {"d_gain_pct", &pid_params.d_gain_pct},
- {"i_gain_pct", &pid_params.i_gain_pct},
- {"deadband", &pid_params.deadband},
- {"setpoint", &pid_params.setpoint},
- {"p_gain_pct", &pid_params.p_gain_pct},
- {NULL, NULL}
+ {"sample_rate_ms", &pid_params.sample_rate_ms, },
+ {"d_gain_pct", &pid_params.d_gain_pct, },
+ {"i_gain_pct", &pid_params.i_gain_pct, },
+ {"deadband", &pid_params.deadband, },
+ {"setpoint", &pid_params.setpoint, },
+ {"p_gain_pct", &pid_params.p_gain_pct, },
+ {NULL, NULL, }
};
-static void __init intel_pstate_debug_expose_params(void)
+static void intel_pstate_debug_expose_params(void)
{
- struct dentry *debugfs_parent;
- int i = 0;
+ int i;
debugfs_parent = debugfs_create_dir("pstate_snb", NULL);
if (IS_ERR_OR_NULL(debugfs_parent))
return;
- while (pid_files[i].name) {
- debugfs_create_file(pid_files[i].name, 0660,
- debugfs_parent, pid_files[i].value,
- &fops_pid_param);
- i++;
+
+ for (i = 0; pid_files[i].name; i++) {
+ struct dentry *dentry;
+
+ dentry = debugfs_create_file(pid_files[i].name, 0660,
+ debugfs_parent, pid_files[i].value,
+ &fops_pid_param);
+ if (!IS_ERR(dentry))
+ pid_files[i].dentry = dentry;
+ }
+}
+
+static void intel_pstate_debug_hide_params(void)
+{
+ int i;
+
+ if (IS_ERR_OR_NULL(debugfs_parent))
+ return;
+
+ for (i = 0; pid_files[i].name; i++) {
+ debugfs_remove(pid_files[i].dentry);
+ pid_files[i].dentry = NULL;
}
+
+ debugfs_remove(debugfs_parent);
+ debugfs_parent = NULL;
}
/************************** debugfs end ************************/
@@ -1051,6 +1072,34 @@ static void __init intel_pstate_debug_expose_params(void)
return sprintf(buf, "%u\n", limits->object); \
}
+static ssize_t intel_pstate_show_status(char *buf);
+static int intel_pstate_update_status(const char *buf, size_t size);
+
+static ssize_t show_status(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ ssize_t ret;
+
+ mutex_lock(&intel_pstate_driver_lock);
+ ret = intel_pstate_show_status(buf);
+ mutex_unlock(&intel_pstate_driver_lock);
+
+ return ret;
+}
+
+static ssize_t store_status(struct kobject *a, struct attribute *b,
+ const char *buf, size_t count)
+{
+ char *p = memchr(buf, '\n', count);
+ int ret;
+
+ mutex_lock(&intel_pstate_driver_lock);
+ ret = intel_pstate_update_status(buf, p ? p - buf : count);
+ mutex_unlock(&intel_pstate_driver_lock);
+
+ return ret < 0 ? ret : count;
+}
+
static ssize_t show_turbo_pct(struct kobject *kobj,
struct attribute *attr, char *buf)
{
@@ -1236,6 +1285,7 @@ static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
show_one(max_perf_pct, max_perf_pct);
show_one(min_perf_pct, min_perf_pct);
+define_one_global_rw(status);
define_one_global_rw(no_turbo);
define_one_global_rw(max_perf_pct);
define_one_global_rw(min_perf_pct);
@@ -1243,6 +1293,7 @@ define_one_global_ro(turbo_pct);
define_one_global_ro(num_pstates);
static struct attribute *intel_pstate_attributes[] = {
+ &status.attr,
&no_turbo.attr,
&turbo_pct.attr,
&num_pstates.attr,
@@ -2329,6 +2380,111 @@ static struct cpufreq_driver intel_cpufreq = {
static struct cpufreq_driver *intel_pstate_driver = &intel_pstate;
+static void intel_pstate_driver_cleanup(void)
+{
+ unsigned int cpu;
+
+ get_online_cpus();
+ for_each_online_cpu(cpu) {
+ if (all_cpu_data[cpu]) {
+ if (intel_pstate_driver == &intel_pstate)
+ intel_pstate_clear_update_util_hook(cpu);
+
+ kfree(all_cpu_data[cpu]);
+ all_cpu_data[cpu] = NULL;
+ }
+ }
+ put_online_cpus();
+}
+
+static int intel_pstate_register_driver(void)
+{
+ int ret;
+
+ ret = cpufreq_register_driver(intel_pstate_driver);
+ if (ret) {
+ intel_pstate_driver_cleanup();
+ return ret;
+ }
+
+ mutex_lock(&intel_pstate_limits_lock);
+ driver_registered = true;
+ mutex_unlock(&intel_pstate_limits_lock);
+
+ if (intel_pstate_driver == &intel_pstate && !hwp_active &&
+ pstate_funcs.get_target_pstate != get_target_pstate_use_cpu_load)
+ intel_pstate_debug_expose_params();
+
+ return 0;
+}
+
+static int intel_pstate_unregister_driver(void)
+{
+ if (hwp_active)
+ return -EBUSY;
+
+ if (intel_pstate_driver == &intel_pstate && !hwp_active &&
+ pstate_funcs.get_target_pstate != get_target_pstate_use_cpu_load)
+ intel_pstate_debug_hide_params();
+
+ mutex_lock(&intel_pstate_limits_lock);
+ driver_registered = false;
+ mutex_unlock(&intel_pstate_limits_lock);
+
+ cpufreq_unregister_driver(intel_pstate_driver);
+ intel_pstate_driver_cleanup();
+
+ return 0;
+}
+
+static ssize_t intel_pstate_show_status(char *buf)
+{
+ if (!driver_registered)
+ return sprintf(buf, "off\n");
+
+ return sprintf(buf, "%s\n", intel_pstate_driver == &intel_pstate ?
+ "active" : "passive");
+}
+
+static int intel_pstate_update_status(const char *buf, size_t size)
+{
+ int ret;
+
+ if (size == 3 && !strncmp(buf, "off", size))
+ return driver_registered ?
+ intel_pstate_unregister_driver() : -EINVAL;
+
+ if (size == 6 && !strncmp(buf, "active", size)) {
+ if (driver_registered) {
+ if (intel_pstate_driver == &intel_pstate)
+ return 0;
+
+ ret = intel_pstate_unregister_driver();
+ if (ret)
+ return ret;
+ }
+
+ intel_pstate_driver = &intel_pstate;
+ return intel_pstate_register_driver();
+ }
+
+ if (size == 7 && !strncmp(buf, "passive", size)) {
+ if (driver_registered) {
+ if (intel_pstate_driver != &intel_pstate)
+ return 0;
+
+ ret = intel_pstate_unregister_driver();
+ if (ret)
+ return ret;
+ }
+
+ intel_pstate_driver = &intel_cpufreq;
+ return intel_pstate_register_driver();
+ }
+
+ return -EINVAL;
+}
+
static int no_load __initdata;
static int no_hwp __initdata;
static int hwp_only __initdata;
@@ -2516,9 +2672,9 @@ static const struct x86_cpu_id hwp_support_ids[] __initconst = {
static int __init intel_pstate_init(void)
{
- int cpu, rc = 0;
const struct x86_cpu_id *id;
struct cpu_defaults *cpu_def;
+ int rc = 0;
if (no_load)
return -ENODEV;
@@ -2550,49 +2706,29 @@ static int __init intel_pstate_init(void)
if (intel_pstate_platform_pwr_mgmt_exists())
return -ENODEV;
+ if (!hwp_active && hwp_only)
+ return -ENOTSUPP;
+
pr_info("Intel P-state driver initializing\n");
all_cpu_data = vzalloc(sizeof(void *) * num_possible_cpus());
if (!all_cpu_data)
return -ENOMEM;
- if (!hwp_active && hwp_only)
- goto out;
-
intel_pstate_request_control_from_smm();
intel_pstate_sysfs_expose_params();
- rc = cpufreq_register_driver(intel_pstate_driver);
- if (rc)
- goto out;
-
mutex_lock(&intel_pstate_driver_lock);
- driver_registered = true;
+ rc = intel_pstate_register_driver();
mutex_unlock(&intel_pstate_driver_lock);
-
- if (intel_pstate_driver == &intel_pstate && !hwp_active &&
- pstate_funcs.get_target_pstate != get_target_pstate_use_cpu_load)
- intel_pstate_debug_expose_params();
+ if (rc)
+ return rc;
if (hwp_active)
pr_info("HWP enabled\n");
- return rc;
-out:
- get_online_cpus();
- for_each_online_cpu(cpu) {
- if (all_cpu_data[cpu]) {
- if (intel_pstate_driver == &intel_pstate)
- intel_pstate_clear_update_util_hook(cpu);
-
- kfree(all_cpu_data[cpu]);
- }
- }
-
- put_online_cpus();
- vfree(all_cpu_data);
- return -ENODEV;
+ return 0;
}
device_initcall(intel_pstate_init);