linux/drivers/acpi/platform_profile.c

// SPDX-License-Identifier: GPL-2.0-or-later

/* Platform profile sysfs interface */

#include <linux/acpi.h>
#include <linux/bits.h>
#include <linux/init.h>
#include <linux/kdev_t.h>
#include <linux/mutex.h>
#include <linux/platform_profile.h>
#include <linux/sysfs.h>

static struct platform_profile_handler *cur_profile;
static DEFINE_MUTEX(profile_lock);

static const char * const profile_names[] = {
	[PLATFORM_PROFILE_LOW_POWER] = "low-power",
	[PLATFORM_PROFILE_COOL] = "cool",
	[PLATFORM_PROFILE_QUIET] = "quiet",
	[PLATFORM_PROFILE_BALANCED] = "balanced",
	[PLATFORM_PROFILE_BALANCED_PERFORMANCE] = "balanced-performance",
	[PLATFORM_PROFILE_PERFORMANCE] = "performance",
};
static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);

static DEFINE_IDA(platform_profile_ida);

static const struct class platform_profile_class = {
	.name = "platform-profile",
};

static ssize_t platform_profile_choices_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	int len = 0;
	int i;

	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
		if (!cur_profile)
			return -ENODEV;
		for_each_set_bit(i, cur_profile->choices, PLATFORM_PROFILE_LAST)
			len += sysfs_emit_at(buf, len, len ? " %s": "%s", profile_names[i]);
	}
	len += sysfs_emit_at(buf, len, "\n");

	return len;
}

static ssize_t platform_profile_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED;
	int err;

	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
		if (!cur_profile)
			return -ENODEV;

		err = cur_profile->profile_get(cur_profile, &profile);
		if (err)
			return err;
	}

	/* Check that profile is valid index */
	if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
		return -EIO;

	return sysfs_emit(buf, "%s\n", profile_names[profile]);
}

static ssize_t platform_profile_store(struct device *dev,
			    struct device_attribute *attr,
			    const char *buf, size_t count)
{
	int err, i;

	/* Scan for a matching profile */
	i = sysfs_match_string(profile_names, buf);
	if (i < 0)
		return -EINVAL;

	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
		if (!cur_profile)
			return -ENODEV;

		/* Check that platform supports this profile choice */
		if (!test_bit(i, cur_profile->choices))
			return -EOPNOTSUPP;

		err = cur_profile->profile_set(cur_profile, i);
		if (err)
			return err;
	}

	sysfs_notify(acpi_kobj, NULL, "platform_profile");

	return count;
}

static DEVICE_ATTR_RO(platform_profile_choices);
static DEVICE_ATTR_RW(platform_profile);

static struct attribute *platform_profile_attrs[] = {
	&dev_attr_platform_profile_choices.attr,
	&dev_attr_platform_profile.attr,
	NULL
};

static int profile_class_registered(struct device *dev, const void *data)
{
	return 1;
}

static umode_t profile_class_is_visible(struct kobject *kobj, struct attribute *attr, int idx)
{
	if (!class_find_device(&platform_profile_class, NULL, NULL, profile_class_registered))
		return 0;
	return attr->mode;
}

static const struct attribute_group platform_profile_group = {
	.attrs = platform_profile_attrs,
	.is_visible = profile_class_is_visible,
};

void platform_profile_notify(struct platform_profile_handler *pprof)
{
	if (!cur_profile)
		return;
	sysfs_notify(acpi_kobj, NULL, "platform_profile");
}
EXPORT_SYMBOL_GPL(platform_profile_notify);

int platform_profile_cycle(void)
{
	enum platform_profile_option profile;
	enum platform_profile_option next;
	int err;

	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
		if (!cur_profile)
			return -ENODEV;

		err = cur_profile->profile_get(cur_profile, &profile);
		if (err)
			return err;

		next = find_next_bit_wrap(cur_profile->choices, PLATFORM_PROFILE_LAST,
					  profile + 1);

		if (WARN_ON(next == PLATFORM_PROFILE_LAST))
			return -EINVAL;

		err = cur_profile->profile_set(cur_profile, next);
		if (err)
			return err;
	}

	sysfs_notify(acpi_kobj, NULL, "platform_profile");

	return 0;
}
EXPORT_SYMBOL_GPL(platform_profile_cycle);

int platform_profile_register(struct platform_profile_handler *pprof)
{
	int err;

	/* Sanity check the profile handler */
	if (!pprof || bitmap_empty(pprof->choices, PLATFORM_PROFILE_LAST) ||
	    !pprof->profile_set || !pprof->profile_get) {
		pr_err("platform_profile: handler is invalid\n");
		return -EINVAL;
	}

	guard(mutex)(&profile_lock);
	/* We can only have one active profile */
	if (cur_profile)
		return -EEXIST;

	/* create class interface for individual handler */
	pprof->minor = ida_alloc(&platform_profile_ida, GFP_KERNEL);
	if (pprof->minor < 0)
		return pprof->minor;
	pprof->class_dev = device_create(&platform_profile_class, pprof->dev,
					 MKDEV(0, 0), pprof, "platform-profile-%d",
					 pprof->minor);
	if (IS_ERR(pprof->class_dev)) {
		err = PTR_ERR(pprof->class_dev);
		goto cleanup_ida;
	}

	cur_profile = pprof;

	err = sysfs_update_group(acpi_kobj, &platform_profile_group);
	if (err)
		goto cleanup_cur;

	return 0;

cleanup_cur:
	cur_profile = NULL;
	device_unregister(pprof->class_dev);

cleanup_ida:
	ida_free(&platform_profile_ida, pprof->minor);

	return err;
}
EXPORT_SYMBOL_GPL(platform_profile_register);

int platform_profile_remove(struct platform_profile_handler *pprof)
{
	int id;
	guard(mutex)(&profile_lock);

	cur_profile = NULL;

	id = pprof->minor;
	device_unregister(pprof->class_dev);
	ida_free(&platform_profile_ida, id);

	sysfs_update_group(acpi_kobj, &platform_profile_group);

	return 0;
}
EXPORT_SYMBOL_GPL(platform_profile_remove);

static int __init platform_profile_init(void)
{
	int err;

	err = class_register(&platform_profile_class);
	if (err)
		return err;

	err = sysfs_create_group(acpi_kobj, &platform_profile_group);
	if (err)
		class_unregister(&platform_profile_class);

	return err;
}

static void __exit platform_profile_exit(void)
{
	sysfs_remove_group(acpi_kobj, &platform_profile_group);
	class_unregister(&platform_profile_class);
}
module_init(platform_profile_init);
module_exit(platform_profile_exit);

MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
MODULE_DESCRIPTION("ACPI platform profile sysfs interface");
MODULE_LICENSE("GPL");