path: root/drivers/acpi/power.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * drivers/acpi/power.c - ACPI Power Resources management.
 *
 * Copyright (C) 2001 - 2015 Intel Corp.
 * Author: Andy Grover <andrew.grover@intel.com>
 * Author: Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 */

/*
 * ACPI power-managed devices may be controlled in two ways:
 * 1. via "Device Specific (D-State) Control"
 * 2. via "Power Resource Control".
 * The code below deals with ACPI Power Resources control.
 *
 * An ACPI "power resource object" represents a software controllable power
 * plane, clock plane, or other resource depended on by a device.
 *
 * A device may rely on multiple power resources, and a power resource
 * may be shared by multiple devices.
 */

#define pr_fmt(fmt) "ACPI: PM: " fmt

#include <linux/dmi.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/sysfs.h>
#include <linux/acpi.h>
#include "sleep.h"
#include "internal.h"

#define ACPI_POWER_CLASS		"power_resource"
#define ACPI_POWER_DEVICE_NAME		"Power Resource"
#define ACPI_POWER_RESOURCE_STATE_OFF	0x00
#define ACPI_POWER_RESOURCE_STATE_ON	0x01
#define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF

struct acpi_power_dependent_device {
	struct device *dev;
	struct list_head node;
};

struct acpi_power_resource {
	struct acpi_device device;
	struct list_head list_node;
	u32 system_level;
	u32 order;
	unsigned int ref_count;
	u8 state;
	struct mutex resource_lock;
	struct list_head dependents;
};

struct acpi_power_resource_entry {
	struct list_head node;
	struct acpi_power_resource *resource;
};

static LIST_HEAD(acpi_power_resource_list);
static DEFINE_MUTEX(power_resource_list_lock);

/* --------------------------------------------------------------------------
                             Power Resource Management
   -------------------------------------------------------------------------- */

static inline const char *resource_dev_name(struct acpi_power_resource *pr)
{
	return dev_name(&pr->device.dev);
}

static inline
struct acpi_power_resource *to_power_resource(struct acpi_device *device)
{
	return container_of(device, struct acpi_power_resource, device);
}

static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
{
	struct acpi_device *device = acpi_fetch_acpi_dev(handle);

	if (!device)
		return NULL;

	return to_power_resource(device);
}

static int acpi_power_resources_list_add(acpi_handle handle,
					 struct list_head *list)
{
	struct acpi_power_resource *resource = acpi_power_get_context(handle);
	struct acpi_power_resource_entry *entry;

	if (!resource || !list)
		return -EINVAL;

	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return -ENOMEM;

	entry->resource = resource;
	if (!list_empty(list)) {
		struct acpi_power_resource_entry *e;

		list_for_each_entry(e, list, node)
			if (e->resource->order > resource->order) {
				list_add_tail(&entry->node, &e->node);
				return 0;
			}
	}
	list_add_tail(&entry->node, list);
	return 0;
}

void acpi_power_resources_list_free(struct list_head *list)
{
	struct acpi_power_resource_entry *entry, *e;

	list_for_each_entry_safe(entry, e, list, node) {
		list_del(&entry->node);
		kfree(entry);
	}
}

static bool acpi_power_resource_is_dup(union acpi_object *package,
				       unsigned int start, unsigned int i)
{
	acpi_handle rhandle, dup;
	unsigned int j;

	/* The caller is expected to check the package element types */
	rhandle = package->package.elements[i].reference.handle;
	for (j = start; j < i; j++) {
		dup = package->package.elements[j].reference.handle;
		if (dup == rhandle)
			return true;
	}

	return false;
}

int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
				 struct list_head *list)
{
	unsigned int i;
	int err = 0;

	for (i = start; i < package->package.count; i++) {
		union acpi_object *element = &package->package.elements[i];
		struct acpi_device *rdev;
		acpi_handle rhandle;

		if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
			err = -ENODATA;
			break;
		}
		rhandle = element->reference.handle;
		if (!rhandle) {
			err = -ENODEV;
			break;
		}

		/* Some ACPI tables contain duplicate power resource references */
		if (acpi_power_resource_is_dup(package, start, i))
			continue;

		rdev = acpi_add_power_resource(rhandle);
		if (!rdev) {
			err = -ENODEV;
			break;
		}
		err = acpi_power_resources_list_add(rhandle, list);
		if (err)
			break;
	}
	if (err)
		acpi_power_resources_list_free(list);

	return err;
}

static int __get_state(acpi_handle handle, u8 *state)
{
	acpi_status status = AE_OK;
	unsigned long long sta = 0;
	u8