@@ -27,6 +27,8 @@
#include <trace/events/thermal.h>
+#define SCALE_ERROR_MITIGATION 100
+
static DEFINE_MUTEX(devfreq_lock);
static DEFINE_IDR(devfreq_idr);
@@ -45,6 +47,12 @@ static DEFINE_IDR(devfreq_idr);
* @freq_table_size: Size of the @freq_table and @power_table
* @power_ops: Pointer to devfreq_cooling_power, used to generate the
* @power_table.
+ * @res_util: Resource utilization scaling factor for the power.
+ * It is multiplied by 100 to minimize the error. It is used
+ * for estimation of the power budget instead of using
+ * 'utilization' (which is 'busy_time / 'total_time').
+ * The 'res_util' range is from 100 to (power_table[state] * 100)
+ * for the corresponding 'state'.
*/
struct devfreq_cooling_device {
int id;
@@ -55,6 +63,7 @@ struct devfreq_cooling_device {
u32 *freq_table;
size_t freq_table_size;
struct devfreq_cooling_power *power_ops;
+ u32 res_util;
};
/**
@@ -292,27 +301,55 @@ static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cd
struct devfreq_dev_status *status = &df->last_status;
unsigned long state;
unsigned long freq = status->current_frequency;
- u32 dyn_power, static_power;
+ unsigned long voltage;
+ u32 dyn_power = 0;
+ u32 static_power = 0;
+ int res;
/* Get dynamic power for state */
state = freq_get_state(dfc, freq);
- if (state == THERMAL_CSTATE_INVALID)
- return -EAGAIN;
+ if (state == THERMAL_CSTATE_INVALID) {
+ res = -EAGAIN;
+ goto fail;
+ }
- dyn_power = dfc->power_table[state];
+ if (dfc->power_ops->get_real_power) {
+ voltage = get_voltage(df, freq);
+ if (voltage == 0) {
+ res = -EINVAL;
+ goto fail;
+ }
- /* Scale dynamic power for utilization */
- dyn_power = (dyn_power * status->busy_time) / status->total_time;
+ res = dfc->power_ops->get_real_power(df, power, freq, voltage);
+ if (!res) {
+ dfc->res_util = dfc->power_table[state];
+ dfc->res_util *= SCALE_ERROR_MITIGATION;
- /* Get static power */
- static_power = get_static_power(dfc, freq);
+ if (*power > 1)
+ dfc->res_util /= *power;
+ } else {
+ goto fail;
+ }
+ } else {
+ dyn_power = dfc->power_table[state];
+
+ /* Scale dynamic power for utilization */
+ dyn_power *= status->busy_time;
+ dyn_power /= status->total_time;
+ /* Get static power */
+ static_power = get_static_power(dfc, freq);
+
+ *power = dyn_power + static_power;
+ }
trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power,
static_power);
- *power = dyn_power + static_power;
-
return 0;
+fail:
+ /* It is safe to set max in this case */
+ dfc->res_util = SCALE_ERROR_MITIGATION;
+ return res;
}
static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
@@ -345,23 +382,30 @@ static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
unsigned long busy_time;
s32 dyn_power;
u32 static_power;
+ s32 est_power;
int i;
- static_power = get_static_power(dfc, freq);
+ if (dfc->power_ops->get_real_power) {
+ /* Scale for resource utilization */
+ est_power = power * dfc->res_util;
+ est_power /= SCALE_ERROR_MITIGATION;
+ } else {
+ static_power = get_static_power(dfc, freq);
- dyn_power = power - static_power;
- dyn_power = dyn_power > 0 ? dyn_power : 0;
+ dyn_power = power - static_power;
+ dyn_power = dyn_power > 0 ? dyn_power : 0;
- /* Scale dynamic power for utilization */
- busy_time = status->busy_time ?: 1;
- dyn_power = (dyn_power * status->total_time) / busy_time;
+ /* Scale dynamic power for utilization */
+ busy_time = status->busy_time ?: 1;
+ est_power = (dyn_power * status->total_time) / busy_time;
+ }
/*
* Find the first cooling state that is within the power
* budget for dynamic power.
*/
for (i = 0; i < dfc->freq_table_size - 1; i++)
- if (dyn_power >= dfc->power_table[i])
+ if (est_power >= dfc->power_table[i])
break;
*state = i;
@@ -34,6 +34,21 @@
* If get_dynamic_power() is NULL, then the
* dynamic power is calculated as
* @dyn_power_coeff * frequency * voltage^2
+ * @get_real_power: When this it is set, the framework uses it to ask the
+ * device driver for the actual power.
+ * Some devices have more sophisticated methods
+ * (like power counters) to approximate the actual power
+ * that they use.
+ * This function provides more accurate data to the
+ * thermal governor. When the driver does not provide
+ * such function, framework just uses pre-calculated
+ * table and scale the power by 'utilization'
+ * (based on 'busy_time' and 'total_time' taken from
+ * devfreq 'last_status').
+ * The value returned by this function must be lower
+ * or equal than the maximum power value
+ * for the current state
+ * (which can be found in power_table[state]).
*/
struct devfreq_cooling_power {
unsigned long (*get_static_power)(struct devfreq *devfreq,
@@ -41,6 +56,8 @@ struct devfreq_cooling_power {
unsigned long (*get_dynamic_power)(struct devfreq *devfreq,
unsigned long freq,
unsigned long voltage);
+ int (*get_real_power)(struct devfreq *df, u32 *power,
+ unsigned long freq, unsigned long voltage);
unsigned long dyn_power_coeff;
};