/*
 *
 * (C) COPYRIGHT 2011-2016 ARM Limited. All rights reserved.
 *
 * This program is free software and is provided to you under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation, and any use by you of this program is subject to the terms
 * of such GNU licence.
 *
 * A copy of the licence is included with the program, and can also be obtained
 * from Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA  02110-1301, USA.
 *
 */


#include <linux/devfreq_cooling.h>
#include <linux/thermal.h>
#include <linux/of.h>
#include <mali_kbase.h>
#include <mali_kbase_defs.h>
#include <backend/gpu/mali_kbase_power_model_simple.h>

/*
 * This model is primarily designed for the Juno platform. It may not be
 * suitable for other platforms.
 */

#define FALLBACK_STATIC_TEMPERATURE 55000

static u32 dynamic_coefficient;
static u32 static_coefficient;
static s32 ts[4];
static struct thermal_zone_device *gpu_tz;

static unsigned long model_static_power(unsigned long voltage)
{
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0)
	unsigned long temperature;
#else
	int temperature;
#endif
	unsigned long temp;
	unsigned long temp_squared, temp_cubed, temp_scaling_factor;
	const unsigned long voltage_cubed = (voltage * voltage * voltage) >> 10;

	if (gpu_tz) {
		int ret;

		ret = gpu_tz->ops->get_temp(gpu_tz, &temperature);
		if (ret) {
			pr_warn_ratelimited("Error reading temperature for gpu thermal zone: %d\n",
					ret);
			temperature = FALLBACK_STATIC_TEMPERATURE;
		}
	} else {
		temperature = FALLBACK_STATIC_TEMPERATURE;
	}

	/* Calculate the temperature scaling factor. To be applied to the
	 * voltage scaled power.
	 */
	temp = temperature / 1000;
	temp_squared = temp * temp;
	temp_cubed = temp_squared * temp;
	temp_scaling_factor =
			(ts[3] * temp_cubed)
			+ (ts[2] * temp_squared)
			+ (ts[1] * temp)
			+ ts[0];

	return (((static_coefficient * voltage_cubed) >> 20)
			* temp_scaling_factor)
				/ 1000000;
}

static unsigned long model_dynamic_power(unsigned long freq,
		unsigned long voltage)
{
	/* The inputs: freq (f) is in Hz, and voltage (v) in mV.
	 * The coefficient (c) is in mW/(MHz mV mV).
	 *
	 * This function calculates the dynamic power after this formula:
	 * Pdyn (mW) = c (mW/(MHz*mV*mV)) * v (mV) * v (mV) * f (MHz)
	 */
	const unsigned long v2 = (voltage * voltage) / 1000; /* m*(V*V) */
	const unsigned long f_mhz = freq / 1000000; /* MHz */

	return (dynamic_coefficient * v2 * f_mhz) / 1000000; /* mW */
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 4, 0)
struct devfreq_cooling_ops power_model_simple_ops = {
#else
struct devfreq_cooling_power power_model_simple_ops = {
#endif
	.get_static_power = model_static_power,
	.get_dynamic_power = model_dynamic_power,
};

int kbase_power_model_simple_init(struct kbase_device *kbdev)
{
	struct device_node *power_model_node;
	const char *tz_name;
	u32 static_power, dynamic_power;
	u32 voltage, voltage_squared, voltage_cubed, frequency;

	power_model_node = of_get_child_by_name(kbdev->dev->of_node,
			"power_model");
	if (!power_model_node) {
		dev_err(kbdev->dev, "could not find power_model node\n");
		return -ENODEV;
	}
	if (!of_device_is_compatible(power_model_node,
			"arm,mali-simple-power-model")) {
		dev_err(kbdev->dev, "power_model incompatible with simple power model\n");
		return -ENODEV;
	}

	if (of_property_read_string(power_model_node, "thermal-zone",
			&tz_name)) {
		dev_err(kbdev->dev, "ts in power_model not available\n");
		return -EINVAL;
	}

	gpu_tz = thermal_zone_get_zone_by_name(tz_name);
	if (IS_ERR(gpu_tz)) {
		pr_warn_ratelimited("Error getting gpu thermal zone (%ld), not yet ready?\n",
				PTR_ERR(gpu_tz));
		gpu_tz = NULL;

		return -EPROBE_DEFER;
	}

	if (of_property_read_u32(power_model_node, "static-power",
			&static_power)) {
		dev_err(kbdev->dev, "static-power in power_model not available\n");
		return -EINVAL;
	}
	if (of_property_read_u32(power_model_node, "dynamic-power",
			&dynamic_power)) {
		dev_err(kbdev->dev, "dynamic-power in power_model not available\n");
		return -EINVAL;
	}
	if (of_property_read_u32(power_model_node, "voltage",
			&voltage)) {
		dev_err(kbdev->dev, "voltage in power_model not available\n");
		return -EINVAL;
	}
	if (of_property_read_u32(power_model_node, "frequency",
			&frequency)) {
		dev_err(kbdev->dev, "frequency in power_model not available\n");
		return -EINVAL;
	}
	voltage_squared = (voltage * voltage) / 1000;
	voltage_cubed = voltage * voltage * voltage;
	static_coefficient = (static_power << 20) / (voltage_cubed >> 10);
	dynamic_coefficient = (((dynamic_power * 1000) / voltage_squared)
			* 1000) / frequency;

	if (of_property_read_u32_array(power_model_node, "ts", (u32 *)ts, 4)) {
		dev_err(kbdev->dev, "ts in power_model not available\n");
		return -EINVAL;
	}

	return 0;
}