222 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright 2024, Intel Corporation4 *5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>6 *7 * Thermal subsystem testing facility.8 *9 * This facility allows the thermal core functionality to be exercised in a10 * controlled way in order to verify its behavior.11 *12 * It resides in the "thermal-testing" directory under the debugfs root and13 * starts with a single file called "command" which can be written a string14 * representing a thermal testing facility command.15 *16 * The currently supported commands are listed in the tt_commands enum below.17 *18 * The "addtz" command causes a new test thermal zone template to be created,19 * for example:20 *21 * # echo addtz > /sys/kernel/debug/thermal-testing/command22 *23 * That template will be represented as a subdirectory in the "thermal-testing"24 * directory, for example25 *26 * # ls /sys/kernel/debug/thermal-testing/27 * command tz028 *29 * The thermal zone template can be populated with trip points with the help of30 * the "tzaddtrip" command, for example:31 *32 * # echo tzaddtrip:0 > /sys/kernel/debug/thermal-testing/command33 *34 * which causes a trip point template to be added to the test thermal zone35 * template 0 (represented by the tz0 subdirectory in "thermal-testing").36 *37 * # ls /sys/kernel/debug/thermal-testing/tz038 * init_temp temp trip_0_temp trip_0_hyst39 *40 * The temperature of a trip point template is initially THERMAL_TEMP_INVALID41 * and its hysteresis is initially 0. They can be adjusted by writing to the42 * "trip_x_temp" and "trip_x_hyst" files correspoinding to that trip point43 * template, respectively.44 *45 * The initial temperature of a thermal zone based on a template can be set by46 * writing to the "init_temp" file in its directory under "thermal-testing", for47 * example:48 *49 * echo 50000 > /sys/kernel/debug/thermal-testing/tz0/init_temp50 *51 * When ready, "tzreg" command can be used for registering and enabling a52 * thermal zone based on a given template with the thermal core, for example53 *54 * # echo tzreg:0 > /sys/kernel/debug/thermal-testing/command55 *56 * In this case, test thermal zone template 0 is used for registering a new57 * thermal zone and the set of trip point templates associated with it is used58 * for populating the new thermal zone's trip points table. The type of the new59 * thermal zone is "test_tz".60 *61 * The temperature and hysteresis of all of the trip points in that new thermal62 * zone are adjustable via sysfs, so they can be updated at any time.63 *64 * The current temperature of the new thermal zone can be set by writing to the65 * "temp" file in the corresponding thermal zone template's directory under66 * "thermal-testing", for example67 *68 * echo 10000 > /sys/kernel/debug/thermal-testing/tz0/temp69 *70 * which will also trigger a temperature update for this zone in the thermal71 * core, including checking its trip points, sending notifications to user space72 * if any of them have been crossed and so on.73 *74 * When it is not needed any more, a test thermal zone template can be deleted75 * with the help of the "deltz" command, for example76 *77 * # echo deltz:0 > /sys/kernel/debug/thermal-testing/command78 *79 * which will also unregister the thermal zone based on it, if present.80 */81 82#define pr_fmt(fmt) "thermal-testing: " fmt83 84#include <linux/debugfs.h>85#include <linux/module.h>86 87#include "thermal_testing.h"88 89struct dentry *d_testing;90 91#define TT_COMMAND_SIZE 1692 93enum tt_commands {94 TT_CMD_ADDTZ,95 TT_CMD_DELTZ,96 TT_CMD_TZADDTRIP,97 TT_CMD_TZREG,98 TT_CMD_TZUNREG,99};100 101static const char *tt_command_strings[] = {102 [TT_CMD_ADDTZ] = "addtz",103 [TT_CMD_DELTZ] = "deltz",104 [TT_CMD_TZADDTRIP] = "tzaddtrip",105 [TT_CMD_TZREG] = "tzreg",106 [TT_CMD_TZUNREG] = "tzunreg",107};108 109static int tt_command_exec(int index, const char *arg)110{111 int ret;112 113 switch (index) {114 case TT_CMD_ADDTZ:115 ret = tt_add_tz();116 break;117 118 case TT_CMD_DELTZ:119 ret = tt_del_tz(arg);120 break;121 122 case TT_CMD_TZADDTRIP:123 ret = tt_zone_add_trip(arg);124 break;125 126 case TT_CMD_TZREG:127 ret = tt_zone_reg(arg);128 break;129 130 case TT_CMD_TZUNREG:131 ret = tt_zone_unreg(arg);132 break;133 134 default:135 ret = -EINVAL;136 break;137 }138 139 return ret;140}141 142static ssize_t tt_command_process(struct dentry *dentry, const char __user *user_buf,143 size_t count)144{145 char *buf __free(kfree);146 char *arg;147 int i;148 149 buf = kmalloc(count + 1, GFP_KERNEL);150 if (!buf)151 return -ENOMEM;152 153 if (copy_from_user(buf, user_buf, count))154 return -EFAULT;155 156 buf[count] = '\0';157 strim(buf);158 159 arg = strstr(buf, ":");160 if (arg) {161 *arg = '\0';162 arg++;163 }164 165 for (i = 0; i < ARRAY_SIZE(tt_command_strings); i++) {166 if (!strcmp(buf, tt_command_strings[i]))167 return tt_command_exec(i, arg);168 }169 170 return -EINVAL;171}172 173static ssize_t tt_command_write(struct file *file, const char __user *user_buf,174 size_t count, loff_t *ppos)175{176 struct dentry *dentry = file->f_path.dentry;177 ssize_t ret;178 179 if (*ppos)180 return -EINVAL;181 182 if (count + 1 > TT_COMMAND_SIZE)183 return -E2BIG;184 185 ret = debugfs_file_get(dentry);186 if (unlikely(ret))187 return ret;188 189 ret = tt_command_process(dentry, user_buf, count);190 if (ret)191 return ret;192 193 return count;194}195 196static const struct file_operations tt_command_fops = {197 .write = tt_command_write,198 .open = simple_open,199 .llseek = default_llseek,200};201 202static int __init thermal_testing_init(void)203{204 d_testing = debugfs_create_dir("thermal-testing", NULL);205 if (!IS_ERR(d_testing))206 debugfs_create_file("command", 0200, d_testing, NULL,207 &tt_command_fops);208 209 return 0;210}211module_init(thermal_testing_init);212 213static void __exit thermal_testing_exit(void)214{215 debugfs_remove(d_testing);216 tt_zone_cleanup();217}218module_exit(thermal_testing_exit);219 220MODULE_DESCRIPTION("Thermal core testing facility");221MODULE_LICENSE("GPL v2");222