2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 04:34:11 +08:00
linux-next/drivers/thermal/cpuidle_cooling.c
Daniel Lezcano dfd0bda370 thermal/drivers/cpuidle_cooling: Change the registration function
Today, there is no user for the cpuidle cooling device. The targetted
platform is ARM and ARM64.

The cpuidle and the cpufreq cooling device are based on the device tree.

As the cpuidle cooling device can have its own configuration depending
on the platform and the available idle states. The DT node description
will give the optional properties to set the cooling device up.

Do no longer rely on the CPU node which is prone to error and will
lead to a confusion in the DT because the cpufreq cooling device is
also using it. Let initialize the cpuidle cooling device with the DT
binding.

This was tested on:
 - hikey960
 - hikey6220
 - rock960
 - db845c

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
Link: https://lore.kernel.org/r/20200429103644.5492-3-daniel.lezcano@linaro.org
2020-05-19 12:55:29 +02:00

272 lines
7.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2019 Linaro Limited.
*
* Author: Daniel Lezcano <daniel.lezcano@linaro.org>
*
*/
#define pr_fmt(fmt) "cpuidle cooling: " fmt
#include <linux/cpu_cooling.h>
#include <linux/cpuidle.h>
#include <linux/err.h>
#include <linux/idle_inject.h>
#include <linux/idr.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/thermal.h>
/**
* struct cpuidle_cooling_device - data for the idle cooling device
* @ii_dev: an atomic to keep track of the last task exiting the idle cycle
* @state: a normalized integer giving the state of the cooling device
*/
struct cpuidle_cooling_device {
struct idle_inject_device *ii_dev;
unsigned long state;
};
static DEFINE_IDA(cpuidle_ida);
/**
* cpuidle_cooling_runtime - Running time computation
* @idle_duration_us: the idle cooling device
* @state: a percentile based number
*
* The running duration is computed from the idle injection duration
* which is fixed. If we reach 100% of idle injection ratio, that
* means the running duration is zero. If we have a 50% ratio
* injection, that means we have equal duration for idle and for
* running duration.
*
* The formula is deduced as follows:
*
* running = idle x ((100 / ratio) - 1)
*
* For precision purpose for integer math, we use the following:
*
* running = (idle x 100) / ratio - idle
*
* For example, if we have an injected duration of 50%, then we end up
* with 10ms of idle injection and 10ms of running duration.
*
* Return: An unsigned int for a usec based runtime duration.
*/
static unsigned int cpuidle_cooling_runtime(unsigned int idle_duration_us,
unsigned long state)
{
if (!state)
return 0;
return ((idle_duration_us * 100) / state) - idle_duration_us;
}
/**
* cpuidle_cooling_get_max_state - Get the maximum state
* @cdev : the thermal cooling device
* @state : a pointer to the state variable to be filled
*
* The function always returns 100 as the injection ratio. It is
* percentile based for consistency accross different platforms.
*
* Return: The function can not fail, it is always zero
*/
static int cpuidle_cooling_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
/*
* Depending on the configuration or the hardware, the running
* cycle and the idle cycle could be different. We want to
* unify that to an 0..100 interval, so the set state
* interface will be the same whatever the platform is.
*
* The state 100% will make the cluster 100% ... idle. A 0%
* injection ratio means no idle injection at all and 50%
* means for 10ms of idle injection, we have 10ms of running
* time.
*/
*state = 100;
return 0;
}
/**
* cpuidle_cooling_get_cur_state - Get the current cooling state
* @cdev: the thermal cooling device
* @state: a pointer to the state
*
* The function just copies the state value from the private thermal
* cooling device structure, the mapping is 1 <-> 1.
*
* Return: The function can not fail, it is always zero
*/
static int cpuidle_cooling_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct cpuidle_cooling_device *idle_cdev = cdev->devdata;
*state = idle_cdev->state;
return 0;
}
/**
* cpuidle_cooling_set_cur_state - Set the current cooling state
* @cdev: the thermal cooling device
* @state: the target state
*
* The function checks first if we are initiating the mitigation which
* in turn wakes up all the idle injection tasks belonging to the idle
* cooling device. In any case, it updates the internal state for the
* cooling device.
*
* Return: The function can not fail, it is always zero
*/
static int cpuidle_cooling_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
{
struct cpuidle_cooling_device *idle_cdev = cdev->devdata;
struct idle_inject_device *ii_dev = idle_cdev->ii_dev;
unsigned long current_state = idle_cdev->state;
unsigned int runtime_us, idle_duration_us;
idle_cdev->state = state;
idle_inject_get_duration(ii_dev, &runtime_us, &idle_duration_us);
runtime_us = cpuidle_cooling_runtime(idle_duration_us, state);
idle_inject_set_duration(ii_dev, runtime_us, idle_duration_us);
if (current_state == 0 && state > 0) {
idle_inject_start(ii_dev);
} else if (current_state > 0 && !state) {
idle_inject_stop(ii_dev);
}
return 0;
}
/**
* cpuidle_cooling_ops - thermal cooling device ops
*/
static struct thermal_cooling_device_ops cpuidle_cooling_ops = {
.get_max_state = cpuidle_cooling_get_max_state,
.get_cur_state = cpuidle_cooling_get_cur_state,
.set_cur_state = cpuidle_cooling_set_cur_state,
};
/**
* __cpuidle_cooling_register: register the cooling device
* @drv: a cpuidle driver structure pointer
* @np: a device node structure pointer used for the thermal binding
*
* This function is in charge of allocating the cpuidle cooling device
* structure, the idle injection, initialize them and register the
* cooling device to the thermal framework.
*
* Return: zero on success, a negative value returned by one of the
* underlying subsystem in case of error
*/
static int __cpuidle_cooling_register(struct device_node *np,
struct cpuidle_driver *drv)
{
struct idle_inject_device *ii_dev;
struct cpuidle_cooling_device *idle_cdev;
struct thermal_cooling_device *cdev;
unsigned int idle_duration_us = TICK_USEC;
unsigned int latency_us = UINT_MAX;
char dev_name[THERMAL_NAME_LENGTH];
int id, ret;
idle_cdev = kzalloc(sizeof(*idle_cdev), GFP_KERNEL);
if (!idle_cdev) {
ret = -ENOMEM;
goto out;
}
id = ida_simple_get(&cpuidle_ida, 0, 0, GFP_KERNEL);
if (id < 0) {
ret = id;
goto out_kfree;
}
ii_dev = idle_inject_register(drv->cpumask);
if (!ii_dev) {
ret = -EINVAL;
goto out_id;
}
of_property_read_u32(np, "duration-us", &idle_duration_us);
of_property_read_u32(np, "exit-latency-us", &latency_us);
idle_inject_set_duration(ii_dev, TICK_USEC, idle_duration_us);
idle_inject_set_latency(ii_dev, latency_us);
idle_cdev->ii_dev = ii_dev;
snprintf(dev_name, sizeof(dev_name), "thermal-idle-%d", id);
cdev = thermal_of_cooling_device_register(np, dev_name, idle_cdev,
&cpuidle_cooling_ops);
if (IS_ERR(cdev)) {
ret = PTR_ERR(cdev);
goto out_unregister;
}
pr_debug("%s: Idle injection set with idle duration=%u, latency=%u\n",
dev_name, idle_duration_us, latency_us);
return 0;
out_unregister:
idle_inject_unregister(ii_dev);
out_id:
ida_simple_remove(&cpuidle_ida, id);
out_kfree:
kfree(idle_cdev);
out:
return ret;
}
/**
* cpuidle_cooling_register - Idle cooling device initialization function
* @drv: a cpuidle driver structure pointer
*
* This function is in charge of creating a cooling device per cpuidle
* driver and register it to the thermal framework.
*
* Return: zero on success, or negative value corresponding to the
* error detected in the underlying subsystems.
*/
void cpuidle_cooling_register(struct cpuidle_driver *drv)
{
struct device_node *cooling_node;
struct device_node *cpu_node;
int cpu, ret;
for_each_cpu(cpu, drv->cpumask) {
cpu_node = of_cpu_device_node_get(cpu);
cooling_node = of_get_child_by_name(cpu_node, "thermal-idle");
of_node_put(cpu_node);
if (!cooling_node) {
pr_debug("'thermal-idle' node not found for cpu%d\n", cpu);
continue;
}
ret = __cpuidle_cooling_register(cooling_node, drv);
of_node_put(cooling_node);
if (ret) {
pr_err("Failed to register the cpuidle cooling device" \
"for cpu%d: %d\n", cpu, ret);
break;
}
}
}