soc: samsung: cpupm: support sysfs to enable/disable power mode

Change-Id: I8f0384bb511a8d9c4aaa57329808e65766ce8b03
Signed-off-by: Park Bumgyu <bumgyu.park@samsung.com>

diff --git a/drivers/soc/samsung/exynos-cpupm.c b/drivers/soc/samsung/exynos-cpupm.c
index c72c36f22e42557a1da99b91acb8deb43fb576d3..fc2c7affab0878bb2cb567ef34977ab6d9860fb7 100644 (file)
--- a/drivers/soc/samsung/exynos-cpupm.c
+++ b/drivers/soc/samsung/exynos-cpupm.c
@@ -396,6 +396,15 @@ struct power_mode {
         * depending on system idle state
         */
        bool            system_idle;
+
+       /*
+        * kobject attribute for sysfs,
+        * it supports for enabling or disabling this power mode
+        */
+       struct kobj_attribute   attr;
+
+       /* user's request for enabling/disabling power mode */
+       bool            user_request;
 };
 
 /* Maximum number of power modes manageable per cpu */
@@ -684,6 +693,87 @@ void exynos_cpu_pm_exit(int cpu, int cancel)
        spin_unlock(&cpupm_lock);
 }
 
+/******************************************************************************
+ *                               sysfs interface                              *
+ ******************************************************************************/
+static ssize_t show_power_mode(struct kobject *kobj,
+                       struct kobj_attribute *attr, char *buf)
+{
+       struct power_mode *mode = container_of(attr, struct power_mode, attr);
+
+       return sprintf(buf, "%s\n",
+               atomic_read(&mode->disable) > 0 ? "disabled" : "enabled");
+}
+
+static ssize_t store_power_mode(struct kobject *kobj,
+                       struct kobj_attribute *attr, const char *buf,
+                       size_t count)
+{
+       unsigned int val;
+       int cpu, type;
+       struct power_mode *mode = container_of(attr, struct power_mode, attr);
+
+       if (!sscanf(buf, "%u", &val))
+               return -EINVAL;
+
+       cpu = cpumask_any(&mode->siblings);
+       type = mode->type;
+
+       val = !!val;
+       if (mode->user_request == val)
+               return count;
+
+       mode->user_request = val;
+       if (val)
+               enable_power_mode(cpu, type);
+       else
+               disable_power_mode(cpu, type);
+
+       return count;
+}
+
+/*
+ * attr_pool is used to create sysfs node at initialization time. Saving the
+ * initiailized attr to attr_pool, and it creates nodes of each attr at the
+ * time of sysfs creation. 10 is the appropriate value for the size of
+ * attr_pool.
+ */
+static struct attribute *attr_pool[10];
+
+static struct kobject *cpupm_kobj;
+static struct attribute_group attr_group;
+
+static void cpupm_sysfs_node_init(int attr_count)
+{
+       attr_group.attrs = kcalloc(attr_count + 1,
+                       sizeof(struct attribute *), GFP_KERNEL);
+       if (!attr_group.attrs)
+               return;
+
+       memcpy(attr_group.attrs, attr_pool,
+               sizeof(struct attribute *) * attr_count);
+
+       cpupm_kobj = kobject_create_and_add("cpupm", power_kobj);
+       if (!cpupm_kobj)
+               goto out;
+
+       if (sysfs_create_group(cpupm_kobj, &attr_group))
+               goto out;
+
+       return;
+
+out:
+       kfree(attr_group.attrs);
+}
+
+#define cpupm_attr_init(_attr, _name, _index)                          \
+       sysfs_attr_init(&_attr.attr);                           \
+       _attr.attr.name = _name;                                \
+       _attr.attr.mode = VERIFY_OCTAL_PERMISSIONS(0644);       \
+       _attr.show      = show_power_mode;                      \
+       _attr.store     = store_power_mode;                     \
+       attr_pool[_index] = &_attr.attr;
+
 /******************************************************************************
  *                                Initialization                              *
  ******************************************************************************/
@@ -708,7 +798,7 @@ static int __init cpu_power_mode_init(void)
        struct device_node *dn = NULL;
        struct power_mode *mode;
        const char *buf;
-       int id = 0;
+       int id = 0, attr_count = 0;
 
        while ((dn = of_find_node_by_type(dn, "cpupm"))) {
                int cpu;
@@ -741,6 +831,22 @@ static int __init cpu_power_mode_init(void)
 
                atomic_set(&mode->disable, 0);
 
+               /*
+                * The users' request is set to enable since initialization state of
+                * power mode is enabled.
+                */
+               mode->user_request = true;
+
+               /*
+                * Initialize attribute for sysfs.
+                * The absence of entry allowed cpu is equivalent to this power
+                * mode being disabled. In this case, no attribute is created.
+                */
+               if (!cpumask_empty(&mode->entry_allowed)) {
+                       cpupm_attr_init(mode->attr, mode->name, attr_count);
+                       attr_count++;
+               }
+
                /* Connect power mode to the cpus in the power domain */
                for_each_cpu(cpu, &mode->siblings)
                        add_mode(per_cpu(cpupm, cpu).modes, mode);
@@ -748,6 +854,9 @@ static int __init cpu_power_mode_init(void)
                cpuidle_profile_group_idle_register(mode->id, mode->name);
        }
 
+       if (attr_count)
+               cpupm_sysfs_node_init(attr_count);
+
        return 0;
 }