// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2024, Intel Corporation
*
* Author: Rafael J. Wysocki <[email protected]>
*
* Thermal subsystem testing facility.
*
* This facility allows the thermal core functionality to be exercised in a
* controlled way in order to verify its behavior.
*
* It resides in the "thermal-testing" directory under the debugfs root and
* starts with a single file called "command" which can be written a string
* representing a thermal testing facility command.
*
* The currently supported commands are listed in the tt_commands enum below.
*
* The "addtz" command causes a new test thermal zone template to be created,
* for example:
*
* # echo addtz > /sys/kernel/debug/thermal-testing/command
*
* That template will be represented as a subdirectory in the "thermal-testing"
* directory, for example
*
* # ls /sys/kernel/debug/thermal-testing/
* command tz0
*
* The thermal zone template can be populated with trip points with the help of
* the "tzaddtrip" command, for example:
*
* # echo tzaddtrip:0 > /sys/kernel/debug/thermal-testing/command
*
* which causes a trip point template to be added to the test thermal zone
* template 0 (represented by the tz0 subdirectory in "thermal-testing").
*
* # ls /sys/kernel/debug/thermal-testing/tz0
* init_temp temp trip_0_temp trip_0_hyst
*
* The temperature of a trip point template is initially THERMAL_TEMP_INVALID
* and its hysteresis is initially 0. They can be adjusted by writing to the
* "trip_x_temp" and "trip_x_hyst" files correspoinding to that trip point
* template, respectively.
*
* The initial temperature of a thermal zone based on a template can be set by
* writing to the "init_temp" file in its directory under "thermal-testing", for
* example:
*
* echo 50000 > /sys/kernel/debug/thermal-testing/tz0/init_temp
*
* When ready, "tzreg" command can be used for registering and enabling a
* thermal zone based on a given template with the thermal core, for example
*
* # echo tzreg:0 > /sys/kernel/debug/thermal-testing/command
*
* In this case, test thermal zone template 0 is used for registering a new
* thermal zone and the set of trip point templates associated with it is used
* for populating the new thermal zone's trip points table. The type of the new
* thermal zone is "test_tz".
*
* The temperature and hysteresis of all of the trip points in that new thermal
* zone are adjustable via sysfs, so they can be updated at any time.
*
* The current temperature of the new thermal zone can be set by writing to the
* "temp" file in the corresponding thermal zone template's directory under
* "thermal-testing", for example
*
* echo 10000 > /sys/kernel/debug/thermal-testing/tz0/temp
*
* which will also trigger a temperature update for this zone in the thermal
* core, including checking its trip points, sending notifications to user space
* if any of them have been crossed and so on.
*
* When it is not needed any more, a test thermal zone template can be deleted
* with the help of the "deltz" command, for example
*
* # echo deltz:0 > /sys/kernel/debug/thermal-testing/command
*
* which will also unregister the thermal zone based on it, if present.
*/
#define pr_fmt(fmt) "thermal-testing: " fmt
#include <linux/debugfs.h>
#include <linux/module.h>
#include "thermal_testing.h"
struct dentry *d_testing;
#define TT_COMMAND_SIZE 16
enum tt_commands {
TT_CMD_ADDTZ,
TT_CMD_DELTZ,
TT_CMD_TZADDTRIP,
TT_CMD_TZREG,
TT_CMD_TZUNREG,
};
static const char *tt_command_strings[] = {
[TT_CMD_ADDTZ] = "addtz",
[TT_CMD_DELTZ] = "deltz",
[TT_CMD_TZADDTRIP] = "tzaddtrip",
[TT_CMD_TZREG] = "tzreg",
[TT_CMD_TZUNREG] = "tzunreg",
};
static int tt_command_exec(int index, const char *arg)
{
int ret;
switch (index) {
case TT_CMD_ADDTZ:
ret = tt_add_tz();
break;
case TT_CMD_DELTZ:
ret = tt_del_tz(arg);
break;
case TT_CMD_TZADDTRIP:
ret = tt_zone_add_trip(arg);
break;
case TT_CMD_TZREG:
ret = tt_zone_reg(arg);
break;
case TT_CMD_TZUNREG:
ret = tt_zone_unreg(arg);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static ssize_t tt_command_process(struct dentry *dentry, const char __user *user_buf,
size_t count)
{
char *buf __free(kfree);
char *arg;
int i;
buf = kmalloc(count + 1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (copy_from_user(buf, user_buf, count))
return -EFAULT;
buf[count] = '\0';
strim(buf);
arg = strstr(buf, ":");
if (arg) {
*arg = '\0';
arg++;
}
for (i = 0; i < ARRAY_SIZE(tt_command_strings); i++) {
if (!strcmp(buf, tt_command_strings[i]))
return tt_command_exec(i, arg);
}
return -EINVAL;
}
static ssize_t tt_command_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct dentry *dentry = file->f_path.dentry;
ssize_t ret;
if (*ppos)
return -EINVAL;
if (count + 1 > TT_COMMAND_SIZE)
return -E2BIG;
ret = debugfs_file_get(dentry);
if (unlikely(ret))
return ret;
ret = tt_command_process(dentry, user_buf, count);
if (ret)
return ret;
return count;
}
static const struct file_operations tt_command_fops = {
.write = tt_command_write,
.open = simple_open,
.llseek = default_llseek,
};
static int __init thermal_testing_init(void)
{
d_testing = debugfs_create_dir("thermal-testing", NULL);
if (!IS_ERR(d_testing))
debugfs_create_file("command", 0200, d_testing, NULL,
&tt_command_fops);
return 0;
}
module_init(thermal_testing_init);
static void __exit thermal_testing_exit(void)
{
debugfs_remove(d_testing);
tt_zone_cleanup();
}
module_exit(thermal_testing_exit);
MODULE_DESCRIPTION("Thermal core testing facility");
MODULE_LICENSE("GPL v2");
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