1 files changed, 221 insertions, 0 deletions
diff --git a/drivers/thermal/testing/command.c b/drivers/thermal/testing/command.c
new file mode 100644
index 000000000000..ba11d70e8021
--- /dev/null
+++ b/drivers/thermal/testing/command.c
@@ -0,0 +1,221 @@
+// 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 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");