// SPDX-License-Identifier: GPL-2.0/* * Copyright 2024, Intel Corporation * * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> * * 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 workqueue_struct *tt_wq __ro_after_init; struct dentry *d_testing __ro_after_init;static struct dentry *d_command __ro_after_init; #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:		if (!arg || !*arg)			return -EINVAL; 		ret = tt_del_tz(arg);		break; 	case TT_CMD_TZADDTRIP:		if (!arg || !*arg)			return -EINVAL; 		ret = tt_zone_add_trip(arg);		break; 	case TT_CMD_TZREG:		if (!arg || !*arg)			return -EINVAL; 		ret = tt_zone_reg(arg);		break; 	case TT_CMD_TZUNREG:		if (!arg || !*arg)			return -EINVAL; 		ret = tt_zone_unreg(arg);		break; 	default:		ret = -EINVAL;		break;	} 	return ret;} static ssize_t tt_command_process(char *s){	char *arg;	int i; 	strim(s); 	arg = strchr(s, ':');	if (arg) {		*arg = '\0';		arg++;	} 	for (i = 0; i < ARRAY_SIZE(tt_command_strings); i++) {		if (!strcmp(s, 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){	char buf[TT_COMMAND_SIZE];	ssize_t ret; 	if (*ppos)		return -EINVAL; 	if (count > TT_COMMAND_SIZE - 1)		return -E2BIG; 	if (copy_from_user(buf, user_buf, count))		return -EFAULT;	buf[count] = '\0'; 	ret = tt_command_process(buf);	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){	int error; 	tt_wq = alloc_workqueue("thermal_testing", WQ_UNBOUND, 0);	if (!tt_wq)		return -ENOMEM; 	d_testing = debugfs_create_dir("thermal-testing", NULL);	if (IS_ERR(d_testing)) {		error = PTR_ERR(d_testing);		goto destroy_wq;	} 	d_command = debugfs_create_file("command", 0200, d_testing, NULL, &tt_command_fops);	if (IS_ERR(d_command)) {		error = PTR_ERR(d_command);		goto remove_d_testing;	} 	return 0; remove_d_testing:	debugfs_remove(d_testing);destroy_wq:	destroy_workqueue(tt_wq);	return error;}module_init(thermal_testing_init); static void __exit thermal_testing_exit(void){	/* First, prevent new commands from being entered. */	debugfs_remove(d_command);	/* Flush commands in progress (if any). */	flush_workqueue(tt_wq);	destroy_workqueue(tt_wq);	/* Remove the directory structure and clean up. */	debugfs_remove(d_testing);	tt_zone_cleanup();}module_exit(thermal_testing_exit); MODULE_DESCRIPTION("Thermal core testing facility");MODULE_LICENSE("GPL v2");