[PATCH v4 7/9] cpufreq: amd-pstate: add frequency dynamic boost sysfs control

[Perry Yuan <Perry.Yuan@amd.com>]

Add one sysfs entry to control the CPU cores frequency boost state
The attribute file can allow user to set max performance boosted or
keeping at normal perf level.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 66 ++++++++++++++++++++++++++++++++++--
 1 file changed, 64 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 645706d65173..b71bfbbb7639 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -765,12 +765,46 @@ static ssize_t show_energy_performance_preference(
 	return  sprintf(buf, "%s\n", energy_perf_strings[preference]);
 }
 
+static void amd_pstate_update_policies(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		cpufreq_update_policy(cpu);
+}
+
+static ssize_t show_boost(struct kobject *kobj,
+				struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%u\n", cppc_boost);
+}
+
+static ssize_t store_boost(struct kobject *a,
+				       struct kobj_attribute *b,
+				       const char *buf, size_t count)
+{
+	bool new_state;
+	int ret;
+
+	ret = kstrtobool(buf, &new_state);
+	if (ret)
+		return -EINVAL;
+
+	mutex_lock(&amd_pstate_driver_lock);
+	cppc_boost = !!new_state;
+	amd_pstate_update_policies();
+	mutex_unlock(&amd_pstate_driver_lock);
+
+	return count;
+}
+
 cpufreq_freq_attr_ro(amd_pstate_max_freq);
 cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
 
 cpufreq_freq_attr_ro(amd_pstate_highest_perf);
 cpufreq_freq_attr_rw(energy_performance_preference);
 cpufreq_freq_attr_ro(energy_performance_available_preferences);
+define_one_global_rw(boost);
 
 static struct freq_attr *amd_pstate_attr[] = {
 	&amd_pstate_max_freq,
@@ -788,6 +822,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
 	NULL,
 };
 
+static struct attribute *pstate_global_attributes[] = {
+	&boost.attr,
+	NULL
+};
+
+static const struct attribute_group amd_pstate_global_attr_group = {
+	.attrs = pstate_global_attributes,
+};
+
 static inline void update_boost_state(void)
 {
 	u64 misc_en;
@@ -1398,9 +1441,28 @@ static int __init amd_pstate_init(void)
 
 	ret = cpufreq_register_driver(default_pstate_driver);
 	if (ret)
-		pr_err("failed to register amd pstate driver with return %d\n",
-		       ret);
+		pr_err("failed to register driver with return %d\n", ret);
+
+	amd_pstate_kobj = kobject_create_and_add("amd-pstate", &cpu_subsys.dev_root->kobj);
+	if (!amd_pstate_kobj) {
+		ret = -EINVAL;
+		pr_err("global sysfs registration failed.\n");
+		goto kobject_free;
+	}
+
+	ret = sysfs_create_group(amd_pstate_kobj, &amd_pstate_global_attr_group);
+	if (ret) {
+		pr_err("sysfs attribute export failed with error %d.\n", ret);
+		goto global_attr_free;
+	}
+
+	return ret;
 
+global_attr_free:
+	kobject_put(amd_pstate_kobj);
+kobject_free:
+	kfree(cpudata);
+	cpufreq_unregister_driver(default_pstate_driver);
 	return ret;
 }
 device_initcall(amd_pstate_init);
-- 
2.34.1