[PATCH v3 7/8] 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 | 53 ++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 841b1e2383b8..6958c5fd9e1c 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -786,12 +786,46 @@ 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_pstate_dynamic_boost(struct kobject *kobj,
+				struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%u\n", cppc_boost);
+}
+
+static ssize_t store_pstate_dynamic_boost(struct kobject *a,
+				       struct kobj_attribute *b,
+				       const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+
+	ret = kstrtouint(buf, 10, &input);
+	if (ret)
+		return ret;
+
+	mutex_lock(&amd_pstate_driver_lock);
+	cppc_boost = !!input;
+	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(pstate_dynamic_boost);
 
 static struct freq_attr *amd_pstate_attr[] = {
 	&amd_pstate_max_freq,
@@ -809,6 +843,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
 	NULL,
 };
 
+static struct attribute *pstate_global_attributes[] = {
+	&pstate_dynamic_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;
@@ -1416,6 +1459,16 @@ static int __init amd_pstate_init(void)
 		pr_err("failed to register amd pstate driver with return %d\n",
 		       ret);
 
+	amd_pstate_kobj = kobject_create_and_add("amd-pstate", &cpu_subsys.dev_root->kobj);
+	if (!amd_pstate_kobj)
+		pr_err("amd-pstate: Global sysfs registration failed.\n");
+
+	ret = sysfs_create_group(amd_pstate_kobj, &amd_pstate_global_attr_group);
+	if (ret) {
+		pr_err("amd-pstate: Sysfs attribute export failed with error %d.\n",
+		       ret);
+	}
+
 	return ret;
 }
 device_initcall(amd_pstate_init);
-- 
2.34.1