u-boot/lib/efi_loader/efi_boottime.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *  EFI application boot time services
 *
 *  Copyright (c) 2016 Alexander Graf
 */

#include <common.h>
#include <div64.h>
#include <efi_loader.h>
#include <environment.h>
#include <malloc.h>
#include <linux/libfdt_env.h>
#include <u-boot/crc.h>
#include <bootm.h>
#include <inttypes.h>
#include <watchdog.h>

DECLARE_GLOBAL_DATA_PTR;

/* Task priority level */
static efi_uintn_t efi_tpl = TPL_APPLICATION;

/* This list contains all the EFI objects our payload has access to */
LIST_HEAD(efi_obj_list);

/* List of all events */
LIST_HEAD(efi_events);

/*
 * If we're running on nasty systems (32bit ARM booting into non-EFI Linux)
 * we need to do trickery with caches. Since we don't want to break the EFI
 * aware boot path, only apply hacks when loading exiting directly (breaking
 * direct Linux EFI booting along the way - oh well).
 */
static bool efi_is_direct_boot = true;

/*
 * EFI can pass arbitrary additional "tables" containing vendor specific
 * information to the payload. One such table is the FDT table which contains
 * a pointer to a flattened device tree blob.
 *
 * In most cases we want to pass an FDT to the payload, so reserve one slot of
 * config table space for it. The pointer gets populated by do_bootefi_exec().
 */
static struct efi_configuration_table __efi_runtime_data efi_conf_table[16];

#ifdef CONFIG_ARM
/*
 * The "gd" pointer lives in a register on ARM and AArch64 that we declare
 * fixed when compiling U-Boot. However, the payload does not know about that
 * restriction so we need to manually swap its and our view of that register on
 * EFI callback entry/exit.
 */
static volatile void *efi_gd, *app_gd;
#endif

static int entry_count;
static int nesting_level;
/* GUID of the device tree table */
const efi_guid_t efi_guid_fdt = EFI_FDT_GUID;
/* GUID of the EFI_DRIVER_BINDING_PROTOCOL */
const efi_guid_t efi_guid_driver_binding_protocol =
			EFI_DRIVER_BINDING_PROTOCOL_GUID;

/* event group ExitBootServices() invoked */
const efi_guid_t efi_guid_event_group_exit_boot_services =
			EFI_EVENT_GROUP_EXIT_BOOT_SERVICES;
/* event group SetVirtualAddressMap() invoked */
const efi_guid_t efi_guid_event_group_virtual_address_change =
			EFI_EVENT_GROUP_VIRTUAL_ADDRESS_CHANGE;
/* event group memory map changed */
const efi_guid_t efi_guid_event_group_memory_map_change =
			EFI_EVENT_GROUP_MEMORY_MAP_CHANGE;
/* event group boot manager about to boot */
const efi_guid_t efi_guid_event_group_ready_to_boot =
			EFI_EVENT_GROUP_READY_TO_BOOT;
/* event group ResetSystem() invoked (before ExitBootServices) */
const efi_guid_t efi_guid_event_group_reset_system =
			EFI_EVENT_GROUP_RESET_SYSTEM;

static efi_status_t EFIAPI efi_disconnect_controller(
					efi_handle_t controller_handle,
					efi_handle_t driver_image_handle,
					efi_handle_t child_handle);

/* Called on every callback entry */
int __efi_entry_check(void)
{
	int ret = entry_count++ == 0;
#ifdef CONFIG_ARM
	assert(efi_gd);
	app_gd = gd;
	gd = efi_gd;
#endif
	return ret;
}

/* Called on every callback exit */
int __efi_exit_check(void)
{
	int ret = --entry_count == 0;
#ifdef CONFIG_ARM
	gd = app_gd;
#endif
	return ret;
}

/* Called from do_bootefi_exec() */
void efi_save_gd(void)
{
#ifdef CONFIG_ARM
	efi_gd = gd;
#endif
}

/*
 * Special case handler for error/abort that just forces things back to u-boot
 * world so we can dump out an abort msg, without any care about returning back
 * to UEFI world.
 */
void efi_restore_gd(void)
{
#ifdef CONFIG_ARM
	/* Only restore if we're already in EFI context */
	if (!efi_gd)
		return;
	gd = efi_gd;
#endif
}

/**
 * indent_string() - returns a string for indenting with two spaces per level
 * @level: indent level
 *
 * A maximum of ten indent levels is supported. Higher indent levels will be
 * truncated.
 *
 * Return: A string for indenting with two spaces per level is
 *         returned.
 */
static const char *indent_string(int level)
{
	const char *indent = "                    ";
	const int max = strlen(indent);

	level = min(max, level * 2);
	return &indent[max - level];
}

const char *__efi_nesting(void)
{
	return indent_string(nesting_level);
}

const char *__efi_nesting_inc(void)
{
	return indent_string(nesting_level++);
}

const char *__efi_nesting_dec(void)
{
	return indent_string(--nesting_level);
}

/**
 * efi_queue_event() - queue an EFI event
 * @event:     event to signal
 * @check_tpl: check the TPL level
 *
 * This function queues the notification function of the event for future
 * execution.
 *
 * The notification function is called if the task priority level of the event
 * is higher than the current task priority level.
 *
 * For the SignalEvent service see efi_signal_event_ext.
 *
 */
static void efi_queue_event(struct efi_event *event, bool check_tpl)
{
	if (event->notify_function) {
		event->is_queued = true;
		/* Check TPL */
		if (check_tpl && efi_tpl >= event->notify_tpl)
			return;
		EFI_CALL_VOID(event->notify_function(event,
						     event->notify_context));
	}
	event->is_queued = false;
}

/**
 * efi_signal_event() - signal an EFI event
 * @event:     event to signal
 * @check_tpl: check the TPL level
 *
 * This function signals an event. If the event belongs to an event group all
 * events of the group are signaled. If they are of type EVT_NOTIFY_SIGNAL
 * their notification function is queued.
 *
 * For the SignalEvent service see efi_signal_event_ext.
 */
void efi_signal_event(struct efi_event *event, bool check_tpl)
{
	if (event->group) {
		struct efi_event *evt;

		/*
		 * The signaled state has to set before executing any
		 * notification function
		 */
		list_for_each_entry(evt, &efi_events, link) {
			if (!evt->group || guidcmp(evt->group, event->group))
				continue;
			if (evt->is_signaled)
				continue;
			evt->is_signaled = true;
			if (evt->type & EVT_NOTIFY_SIGNAL &&
			    evt->notify_function)
				evt->is_queued = true;
		}
		list_for_each_entry(evt, &efi_events, link) {
			if (!evt->group || guidcmp(evt->group, event->group))
				continue;
			if (evt->is_queued)
				efi_queue_event(evt, check_tpl);
		}
	} else if (!event->is_signaled) {
		event->is_signaled = true;
		if (event->type & EVT_NOTIFY_SIGNAL)
			efi_queue_event(event, check_tpl);
	}
}

/**
 * efi_raise_tpl() - raise the task priority level
 * @new_tpl: new value of the task priority level
 *
 * This function implements the RaiseTpl service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: old value of the task priority level
 */
static unsigned long EFIAPI efi_raise_tpl(efi_uintn_t new_tpl)
{
	efi_uintn_t old_tpl = efi_tpl;

	EFI_ENTRY("0x%zx", new_tpl);

	if (new_tpl < efi_tpl)
		debug("WARNING: new_tpl < current_tpl in %s\n", __func__);
	efi_tpl = new_tpl;
	if (efi_tpl > TPL_HIGH_LEVEL)
		efi_tpl = TPL_HIGH_LEVEL;

	EFI_EXIT(EFI_SUCCESS);
	return old_tpl;
}

/**
 * efi_restore_tpl() - lower the task priority level
 * @old_tpl: value of the task priority level to be restored
 *
 * This function implements the RestoreTpl service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 */
static void EFIAPI efi_restore_tpl(efi_uintn_t old_tpl)
{
	EFI_ENTRY("0x%zx", old_tpl);

	if (old_tpl > efi_tpl)
		debug("WARNING: old_tpl > current_tpl in %s\n", __func__);
	efi_tpl = old_tpl;
	if (efi_tpl > TPL_HIGH_LEVEL)
		efi_tpl = TPL_HIGH_LEVEL;

	/*
	 * Lowering the TPL may have made queued events eligible for execution.
	 */
	efi_timer_check();

	EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_allocate_pages_ext() - allocate memory pages
 * @type:        type of allocation to be performed
 * @memory_type: usage type of the allocated memory
 * @pages:       number of pages to be allocated
 * @memory:      allocated memory
 *
 * This function implements the AllocatePages service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_allocate_pages_ext(int type, int memory_type,
						  efi_uintn_t pages,
						  uint64_t *memory)
{
	efi_status_t r;

	EFI_ENTRY("%d, %d, 0x%zx, %p", type, memory_type, pages, memory);
	r = efi_allocate_pages(type, memory_type, pages, memory);
	return EFI_EXIT(r);
}

/**
 * efi_free_pages_ext() - Free memory pages.
 * @memory: start of the memory area to be freed
 * @pages:  number of pages to be freed
 *
 * This function implements the FreePages service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_free_pages_ext(uint64_t memory,
					      efi_uintn_t pages)
{
	efi_status_t r;

	EFI_ENTRY("%" PRIx64 ", 0x%zx", memory, pages);
	r = efi_free_pages(memory, pages);
	return EFI_EXIT(r);
}

/**
 * efi_get_memory_map_ext() - get map describing memory usage
 * @memory_map_size:    on entry the size, in bytes, of the memory map buffer,
 *                      on exit the size of the copied memory map
 * @memory_map:         buffer to which the memory map is written
 * @map_key:            key for the memory map
 * @descriptor_size:    size of an individual memory descriptor
 * @descriptor_version: version number of the memory descriptor structure
 *
 * This function implements the GetMemoryMap service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_get_memory_map_ext(
					efi_uintn_t *memory_map_size,
					struct efi_mem_desc *memory_map,
					efi_uintn_t *map_key,
					efi_uintn_t *descriptor_size,
					uint32_t *descriptor_version)
{
	efi_status_t r;

	EFI_ENTRY("%p, %p, %p, %p, %p", memory_map_size, memory_map,
		  map_key, descriptor_size, descriptor_version);
	r = efi_get_memory_map(memory_map_size, memory_map, map_key,
			       descriptor_size, descriptor_version);
	return EFI_EXIT(r);
}

/**
 * efi_allocate_pool_ext() - allocate memory from pool
 * @pool_type: type of the pool from which memory is to be allocated
 * @size:      number of bytes to be allocated
 * @buffer:    allocated memory
 *
 * This function implements the AllocatePool service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_allocate_pool_ext(int pool_type,
						 efi_uintn_t size,
						 void **buffer)
{
	efi_status_t r;

	EFI_ENTRY("%d, %zd, %p", pool_type, size, buffer);
	r = efi_allocate_pool(pool_type, size, buffer);
	return EFI_EXIT(r);
}

/**
 * efi_free_pool_ext() - free memory from pool
 * @buffer: start of memory to be freed
 *
 * This function implements the FreePool service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_free_pool_ext(void *buffer)
{
	efi_status_t r;

	EFI_ENTRY("%p", buffer);
	r = efi_free_pool(buffer);
	return EFI_EXIT(r);
}

/**
 * efi_add_handle() - add a new object to the object list
 * @obj: object to be added
 *
 * The protocols list is initialized. The object handle is set.
 */
void efi_add_handle(struct efi_object *obj)
{
	if (!obj)
		return;
	INIT_LIST_HEAD(&obj->protocols);
	obj->handle = obj;
	list_add_tail(&obj->link, &efi_obj_list);
}

/**
 * efi_create_handle() - create handle
 * @handle: new handle
 *
 * Return: status code
 */
efi_status_t efi_create_handle(efi_handle_t *handle)
{
	struct efi_object *obj;

	obj = calloc(1, sizeof(struct efi_object));
	if (!obj)
		return EFI_OUT_OF_RESOURCES;

	efi_add_handle(obj);
	*handle = obj->handle;

	return EFI_SUCCESS;
}

/**
 * efi_search_protocol() - find a protocol on a handle.
 * @handle:        handle
 * @protocol_guid: GUID of the protocol
 * @handler:       reference to the protocol
 *
 * Return: status code
 */
efi_status_t efi_search_protocol(const efi_handle_t handle,
				 const efi_guid_t *protocol_guid,
				 struct efi_handler **handler)
{
	struct efi_object *efiobj;
	struct list_head *lhandle;

	if (!handle || !protocol_guid)
		return EFI_INVALID_PARAMETER;
	efiobj = efi_search_obj(handle);
	if (!efiobj)
		return EFI_INVALID_PARAMETER;
	list_for_each(lhandle, &efiobj->protocols) {
		struct efi_handler *protocol;

		protocol = list_entry(lhandle, struct efi_handler, link);
		if (!guidcmp(protocol->guid, protocol_guid)) {
			if (handler)
				*handler = protocol;
			return EFI_SUCCESS;
		}
	}
	return EFI_NOT_FOUND;
}

/**
 * efi_remove_protocol() - delete protocol from a handle
 * @handle:             handle from which the protocol shall be deleted
 * @protocol:           GUID of the protocol to be deleted
 * @protocol_interface: interface of the protocol implementation
 *
 * Return: status code
 */
efi_status_t efi_remove_protocol(const efi_handle_t handle,
				 const efi_guid_t *protocol,
				 void *protocol_interface)
{
	struct efi_handler *handler;
	efi_status_t ret;

	ret = efi_search_protocol(handle, protocol, &handler);
	if (ret != EFI_SUCCESS)
		return ret;
	if (guidcmp(handler->guid, protocol))
		return EFI_INVALID_PARAMETER;
	if (handler->protocol_interface != protocol_interface)
		return EFI_INVALID_PARAMETER;
	list_del(&handler->link);
	free(handler);
	return EFI_SUCCESS;
}

/**
 * efi_remove_all_protocols() - delete all protocols from a handle
 * @handle: handle from which the protocols shall be deleted
 *
 * Return: status code
 */
efi_status_t efi_remove_all_protocols(const efi_handle_t handle)
{
	struct efi_object *efiobj;
	struct efi_handler *protocol;
	struct efi_handler *pos;

	efiobj = efi_search_obj(handle);
	if (!efiobj)
		return EFI_INVALID_PARAMETER;
	list_for_each_entry_safe(protocol, pos, &efiobj->protocols, link) {
		efi_status_t ret;

		ret = efi_remove_protocol(handle, protocol->guid,
					  protocol->protocol_interface);
		if (ret != EFI_SUCCESS)
			return ret;
	}
	return EFI_SUCCESS;
}

/**
 * efi_delete_handle() - delete handle
 *
 * @obj: handle to delete
 */
void efi_delete_handle(struct efi_object *obj)
{
	if (!obj)
		return;
	efi_remove_all_protocols(obj->handle);
	list_del(&obj->link);
	free(obj);
}

/**
 * efi_is_event() - check if a pointer is a valid event
 * @event: pointer to check
 *
 * Return: status code
 */
static efi_status_t efi_is_event(const struct efi_event *event)
{
	const struct efi_event *evt;

	if (!event)
		return EFI_INVALID_PARAMETER;
	list_for_each_entry(evt, &efi_events, link) {
		if (evt == event)
			return EFI_SUCCESS;
	}
	return EFI_INVALID_PARAMETER;
}

/**
 * efi_create_event() - create an event
 * @type:            type of the event to create
 * @notify_tpl:      task priority level of the event
 * @notify_function: notification function of the event
 * @notify_context:  pointer passed to the notification function
 * @group:           event group
 * @event:           created event
 *
 * This function is used inside U-Boot code to create an event.
 *
 * For the API function implementing the CreateEvent service see
 * efi_create_event_ext.
 *
 * Return: status code
 */
efi_status_t efi_create_event(uint32_t type, efi_uintn_t notify_tpl,
			      void (EFIAPI *notify_function) (
					struct efi_event *event,
					void *context),
			      void *notify_context, efi_guid_t *group,
			      struct efi_event **event)
{
	struct efi_event *evt;

	if (event == NULL)
		return EFI_INVALID_PARAMETER;

	if ((type & EVT_NOTIFY_SIGNAL) && (type & EVT_NOTIFY_WAIT))
		return EFI_INVALID_PARAMETER;

	if ((type & (EVT_NOTIFY_SIGNAL | EVT_NOTIFY_WAIT)) &&
	    notify_function == NULL)
		return EFI_INVALID_PARAMETER;

	evt = calloc(1, sizeof(struct efi_event));
	if (!evt)
		return EFI_OUT_OF_RESOURCES;
	evt->type = type;
	evt->notify_tpl = notify_tpl;
	evt->notify_function = notify_function;
	evt->notify_context = notify_context;
	evt->group = group;
	/* Disable timers on bootup */
	evt->trigger_next = -1ULL;
	evt->is_queued = false;
	evt->is_signaled = false;
	list_add_tail(&evt->link, &efi_events);
	*event = evt;
	return EFI_SUCCESS;
}

/*
 * efi_create_event_ex() - create an event in a group
 * @type:            type of the event to create
 * @notify_tpl:      task priority level of the event
 * @notify_function: notification function of the event
 * @notify_context:  pointer passed to the notification function
 * @event:           created event
 * @event_group:     event group
 *
 * This function implements the CreateEventEx service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
efi_status_t EFIAPI efi_create_event_ex(uint32_t type, efi_uintn_t notify_tpl,
					void (EFIAPI *notify_function) (
							struct efi_event *event,
							void *context),
					void *notify_context,
					efi_guid_t *event_group,
					struct efi_event **event)
{
	EFI_ENTRY("%d, 0x%zx, %p, %p, %pUl", type, notify_tpl, notify_function,
		  notify_context, event_group);
	return EFI_EXIT(efi_create_event(type, notify_tpl, notify_function,
					 notify_context, event_group, event));
}

/**
 * efi_create_event_ext() - create an event
 * @type:            type of the event to create
 * @notify_tpl:      task priority level of the event
 * @notify_function: notification function of the event
 * @notify_context:  pointer passed to the notification function
 * @event:           created event
 *
 * This function implements the CreateEvent service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_create_event_ext(
			uint32_t type, efi_uintn_t notify_tpl,
			void (EFIAPI *notify_function) (
					struct efi_event *event,
					void *context),
			void *notify_context, struct efi_event **event)
{
	EFI_ENTRY("%d, 0x%zx, %p, %p", type, notify_tpl, notify_function,
		  notify_context);
	return EFI_EXIT(efi_create_event(type, notify_tpl, notify_function,
					 notify_context, NULL, event));
}

/**
 * efi_timer_check() - check if a timer event has occurred
 *
 * Check if a timer event has occurred or a queued notification function should
 * be called.
 *
 * Our timers have to work without interrupts, so we check whenever keyboard
 * input or disk accesses happen if enough time elapsed for them to fire.
 */
void efi_timer_check(void)
{
	struct efi_event *evt;
	u64 now = timer_get_us();

	list_for_each_entry(evt, &efi_events, link) {
		if (evt->is_queued)
			efi_queue_event(evt, true);
		if (!(evt->type & EVT_TIMER) || now < evt->trigger_next)
			continue;
		switch (evt->trigger_type) {
		case EFI_TIMER_RELATIVE:
			evt->trigger_type = EFI_TIMER_STOP;
			break;
		case EFI_TIMER_PERIODIC:
			evt->trigger_next += evt->trigger_time;
			break;
		default:
			continue;
		}
		evt->is_signaled = false;
		efi_signal_event(evt, true);
	}
	WATCHDOG_RESET();
}

/**
 * efi_set_timer() - set the trigger time for a timer event or stop the event
 * @event:        event for which the timer is set
 * @type:         type of the timer
 * @trigger_time: trigger period in multiples of 100ns
 *
 * This is the function for internal usage in U-Boot. For the API function
 * implementing the SetTimer service see efi_set_timer_ext.
 *
 * Return: status code
 */
efi_status_t efi_set_timer(struct efi_event *event, enum efi_timer_delay type,
			   uint64_t trigger_time)
{
	/* Check that the event is valid */
	if (efi_is_event(event) != EFI_SUCCESS || !(event->type & EVT_TIMER))
		return EFI_INVALID_PARAMETER;

	/*
	 * The parameter defines a multiple of 100ns.
	 * We use multiples of 1000ns. So divide by 10.
	 */
	do_div(trigger_time, 10);

	switch (type) {
	case EFI_TIMER_STOP:
		event->trigger_next = -1ULL;
		break;
	case EFI_TIMER_PERIODIC:
	case EFI_TIMER_RELATIVE:
		event->trigger_next = timer_get_us() + trigger_time;
		break;
	default:
		return EFI_INVALID_PARAMETER;
	}
	event->trigger_type = type;
	event->trigger_time = trigger_time;
	event->is_signaled = false;
	return EFI_SUCCESS;
}

/**
 * efi_set_timer_ext() - Set the trigger time for a timer event or stop the
 *                       event
 * @event:        event for which the timer is set
 * @type:         type of the timer
 * @trigger_time: trigger period in multiples of 100ns
 *
 * This function implements the SetTimer service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_set_timer_ext(struct efi_event *event,
					     enum efi_timer_delay type,
					     uint64_t trigger_time)
{
	EFI_ENTRY("%p, %d, %" PRIx64, event, type, trigger_time);
	return EFI_EXIT(efi_set_timer(event, type, trigger_time));
}

/**
 * efi_wait_for_event() - wait for events to be signaled
 * @num_events: number of events to be waited for
 * @event:      events to be waited for
 * @index:      index of the event that was signaled
 *
 * This function implements the WaitForEvent service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_wait_for_event(efi_uintn_t num_events,
					      struct efi_event **event,
					      efi_uintn_t *index)
{
	int i;

	EFI_ENTRY("%zd, %p, %p", num_events, event, index);

	/* Check parameters */
	if (!num_events || !event)
		return EFI_EXIT(EFI_INVALID_PARAMETER);
	/* Check TPL */
	if (efi_tpl != TPL_APPLICATION)
		return EFI_EXIT(EFI_UNSUPPORTED);
	for (i = 0; i < num_events; ++i) {
		if (efi_is_event(event[i]) != EFI_SUCCESS)
			return EFI_EXIT(EFI_INVALID_PARAMETER);
		if (!event[i]->type || event[i]->type & EVT_NOTIFY_SIGNAL)
			return EFI_EXIT(EFI_INVALID_PARAMETER);
		if (!event[i]->is_signaled)
			efi_queue_event(event[i], true);
	}

	/* Wait for signal */
	for (;;) {
		for (i = 0; i < num_events; ++i) {
			if (event[i]->is_signaled)
				goto out;
		}
		/* Allow events to occur. */
		efi_timer_check();
	}

out:
	/*
	 * Reset the signal which is passed to the caller to allow periodic
	 * events to occur.
	 */
	event[i]->is_signaled = false;
	if (index)
		*index = i;

	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_signal_event_ext() - signal an EFI event
 * @event: event to signal
 *
 * This function implements the SignalEvent service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * This functions sets the signaled state of the event and queues the
 * notification function for execution.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_signal_event_ext(struct efi_event *event)
{
	EFI_ENTRY("%p", event);
	if (efi_is_event(event) != EFI_SUCCESS)
		return EFI_EXIT(EFI_INVALID_PARAMETER);
	efi_signal_event(event, true);
	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_close_event() - close an EFI event
 * @event: event to close
 *
 * This function implements the CloseEvent service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_close_event(struct efi_event *event)
{
	EFI_ENTRY("%p", event);
	if (efi_is_event(event) != EFI_SUCCESS)
		return EFI_EXIT(EFI_INVALID_PARAMETER);
	list_del(&event->link);
	free(event);
	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_check_event() - check if an event is signaled
 * @event: event to check
 *
 * This function implements the CheckEvent service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * If an event is not signaled yet, the notification function is queued. The
 * signaled state is cleared.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_check_event(struct efi_event *event)
{
	EFI_ENTRY("%p", event);
	efi_timer_check();
	if (efi_is_event(event) != EFI_SUCCESS ||
	    event->type & EVT_NOTIFY_SIGNAL)
		return EFI_EXIT(EFI_INVALID_PARAMETER);
	if (!event->is_signaled)
		efi_queue_event(event, true);
	if (event->is_signaled) {
		event->is_signaled = false;
		return EFI_EXIT(EFI_SUCCESS);
	}
	return EFI_EXIT(EFI_NOT_READY);
}

/**
 * efi_search_obj() - find the internal EFI object for a handle
 * @handle: handle to find
 *
 * Return: EFI object
 */
struct efi_object *efi_search_obj(const efi_handle_t handle)
{
	struct efi_object *efiobj;

	list_for_each_entry(efiobj, &efi_obj_list, link) {
		if (efiobj->handle == handle)
			return efiobj;
	}

	return NULL;
}

/**
 * efi_open_protocol_info_entry() - create open protocol info entry and add it
 *                                  to a protocol
 * @handler: handler of a protocol
 *
 * Return: open protocol info entry
 */
static struct efi_open_protocol_info_entry *efi_create_open_info(
			struct efi_handler *handler)
{
	struct efi_open_protocol_info_item *item;

	item = calloc(1, sizeof(struct efi_open_protocol_info_item));
	if (!item)
		return NULL;
	/* Append the item to the open protocol info list. */
	list_add_tail(&item->link, &handler->open_infos);

	return &item->info;
}

/**
 * efi_delete_open_info() - remove an open protocol info entry from a protocol
 * @item: open protocol info entry to delete
 *
 * Return: status code
 */
static efi_status_t efi_delete_open_info(
			struct efi_open_protocol_info_item *item)
{
	list_del(&item->link);
	free(item);
	return EFI_SUCCESS;
}

/**
 * efi_add_protocol() - install new protocol on a handle
 * @handle:             handle on which the protocol shall be installed
 * @protocol:           GUID of the protocol to be installed
 * @protocol_interface: interface of the protocol implementation
 *
 * Return: status code
 */
efi_status_t efi_add_protocol(const efi_handle_t handle,
			      const efi_guid_t *protocol,
			      void *protocol_interface)
{
	struct efi_object *efiobj;
	struct efi_handler *handler;
	efi_status_t ret;

	efiobj = efi_search_obj(handle);
	if (!efiobj)
		return EFI_INVALID_PARAMETER;
	ret = efi_search_protocol(handle, protocol, NULL);
	if (ret != EFI_NOT_FOUND)
		return EFI_INVALID_PARAMETER;
	handler = calloc(1, sizeof(struct efi_handler));
	if (!handler)
		return EFI_OUT_OF_RESOURCES;
	handler->guid = protocol;
	handler->protocol_interface = protocol_interface;
	INIT_LIST_HEAD(&handler->open_infos);
	list_add_tail(&handler->link, &efiobj->protocols);
	if (!guidcmp(&efi_guid_device_path, protocol))
		EFI_PRINT("installed device path '%pD'\n", protocol_interface);
	return EFI_SUCCESS;
}

/**
 * efi_install_protocol_interface() - install protocol interface
 * @handle:                  handle on which the protocol shall be installed
 * @protocol:                GUID of the protocol to be installed
 * @protocol_interface_type: type of the interface to be installed,
 *                           always EFI_NATIVE_INTERFACE
 * @protocol_interface:      interface of the protocol implementation
 *
 * This function implements the InstallProtocolInterface service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_install_protocol_interface(
			void **handle, const efi_guid_t *protocol,
			int protocol_interface_type, void *protocol_interface)
{
	efi_status_t r;

	EFI_ENTRY("%p, %pUl, %d, %p", handle, protocol, protocol_interface_type,
		  protocol_interface);

	if (!handle || !protocol ||
	    protocol_interface_type != EFI_NATIVE_INTERFACE) {
		r = EFI_INVALID_PARAMETER;
		goto out;
	}

	/* Create new handle if requested. */
	if (!*handle) {
		r = efi_create_handle(handle);
		if (r != EFI_SUCCESS)
			goto out;
		debug("%sEFI: new handle %p\n", indent_string(nesting_level),
		      *handle);
	} else {
		debug("%sEFI: handle %p\n", indent_string(nesting_level),
		      *handle);
	}
	/* Add new protocol */
	r = efi_add_protocol(*handle, protocol, protocol_interface);
out:
	return EFI_EXIT(r);
}

/**
 * efi_get_drivers() - get all drivers associated to a controller
 * @efiobj:               handle of the controller
 * @protocol:             protocol guid (optional)
 * @number_of_drivers:    number of child controllers
 * @driver_handle_buffer: handles of the the drivers
 *
 * The allocated buffer has to be freed with free().
 *
 * Return: status code
 */
static efi_status_t efi_get_drivers(struct efi_object *efiobj,
				    const efi_guid_t *protocol,
				    efi_uintn_t *number_of_drivers,
				    efi_handle_t **driver_handle_buffer)
{
	struct efi_handler *handler;
	struct efi_open_protocol_info_item *item;
	efi_uintn_t count = 0, i;
	bool duplicate;

	/* Count all driver associations */
	list_for_each_entry(handler, &efiobj->protocols, link) {
		if (protocol && guidcmp(handler->guid, protocol))
			continue;
		list_for_each_entry(item, &handler->open_infos, link) {
			if (item->info.attributes &
			    EFI_OPEN_PROTOCOL_BY_DRIVER)
				++count;
		}
	}
	/*
	 * Create buffer. In case of duplicate driver assignments the buffer
	 * will be too large. But that does not harm.
	 */
	*number_of_drivers = 0;
	*driver_handle_buffer = calloc(count, sizeof(efi_handle_t));
	if (!*driver_handle_buffer)
		return EFI_OUT_OF_RESOURCES;
	/* Collect unique driver handles */
	list_for_each_entry(handler, &efiobj->protocols, link) {
		if (protocol && guidcmp(handler->guid, protocol))
			continue;
		list_for_each_entry(item, &handler->open_infos, link) {
			if (item->info.attributes &
			    EFI_OPEN_PROTOCOL_BY_DRIVER) {
				/* Check this is a new driver */
				duplicate = false;
				for (i = 0; i < *number_of_drivers; ++i) {
					if ((*driver_handle_buffer)[i] ==
					    item->info.agent_handle)
						duplicate = true;
				}
				/* Copy handle to buffer */
				if (!duplicate) {
					i = (*number_of_drivers)++;
					(*driver_handle_buffer)[i] =
						item->info.agent_handle;
				}
			}
		}
	}
	return EFI_SUCCESS;
}

/**
 * efi_disconnect_all_drivers() - disconnect all drivers from a controller
 * @efiobj:       handle of the controller
 * @protocol:     protocol guid (optional)
 * @child_handle: handle of the child to destroy
 *
 * This function implements the DisconnectController service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t efi_disconnect_all_drivers(
				struct efi_object *efiobj,
				const efi_guid_t *protocol,
				efi_handle_t child_handle)
{
	efi_uintn_t number_of_drivers;
	efi_handle_t *driver_handle_buffer;
	efi_status_t r, ret;

	ret = efi_get_drivers(efiobj, protocol, &number_of_drivers,
			      &driver_handle_buffer);
	if (ret != EFI_SUCCESS)
		return ret;

	ret = EFI_NOT_FOUND;
	while (number_of_drivers) {
		r = EFI_CALL(efi_disconnect_controller(
				efiobj->handle,
				driver_handle_buffer[--number_of_drivers],
				child_handle));
		if (r == EFI_SUCCESS)
			ret = r;
	}
	free(driver_handle_buffer);
	return ret;
}

/**
 * efi_uninstall_protocol_interface() - uninstall protocol interface
 * @handle:             handle from which the protocol shall be removed
 * @protocol:           GUID of the protocol to be removed
 * @protocol_interface: interface to be removed
 *
 * This function implements the UninstallProtocolInterface service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_uninstall_protocol_interface(
				efi_handle_t handle, const efi_guid_t *protocol,
				void *protocol_interface)
{
	struct efi_object *efiobj;
	struct efi_handler *handler;
	struct efi_open_protocol_info_item *item;
	struct efi_open_protocol_info_item *pos;
	efi_status_t r;

	EFI_ENTRY("%p, %pUl, %p", handle, protocol, protocol_interface);

	/* Check handle */
	efiobj = efi_search_obj(handle);
	if (!efiobj) {
		r = EFI_INVALID_PARAMETER;
		goto out;
	}
	/* Find the protocol on the handle */
	r = efi_search_protocol(handle, protocol, &handler);
	if (r != EFI_SUCCESS)
		goto out;
	/* Disconnect controllers */
	efi_disconnect_all_drivers(efiobj, protocol, NULL);
	if (!list_empty(&handler->open_infos)) {
		r =  EFI_ACCESS_DENIED;
		goto out;
	}
	/* Close protocol */
	list_for_each_entry_safe(item, pos, &handler->open_infos, link) {
		if (item->info.attributes ==
			EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL ||
		    item->info.attributes == EFI_OPEN_PROTOCOL_GET_PROTOCOL ||
		    item->info.attributes == EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
			list_del(&item->link);
	}
	if (!list_empty(&handler->open_infos)) {
		r =  EFI_ACCESS_DENIED;
		goto out;
	}
	r = efi_remove_protocol(handle, protocol, protocol_interface);
out:
	return EFI_EXIT(r);
}

/**
 * efi_register_protocol_notify() - register an event for notification when a
 *                                  protocol is installed.
 * @protocol:     GUID of the protocol whose installation shall be notified
 * @event:        event to be signaled upon installation of the protocol
 * @registration: key for retrieving the registration information
 *
 * This function implements the RegisterProtocolNotify service.
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_register_protocol_notify(
						const efi_guid_t *protocol,
						struct efi_event *event,
						void **registration)
{
	EFI_ENTRY("%pUl, %p, %p", protocol, event, registration);
	return EFI_EXIT(EFI_OUT_OF_RESOURCES);
}

/**
 * efi_search() - determine if an EFI handle implements a protocol
 * @search_type: selection criterion
 * @protocol:    GUID of the protocol
 * @search_key:  registration key
 * @efiobj:      handle
 *
 * See the documentation of the LocateHandle service in the UEFI specification.
 *
 * Return: 0 if the handle implements the protocol
 */
static int efi_search(enum efi_locate_search_type search_type,
		      const efi_guid_t *protocol, void *search_key,
		      struct efi_object *efiobj)
{
	efi_status_t ret;

	switch (search_type) {
	case ALL_HANDLES:
		return 0;
	case BY_REGISTER_NOTIFY:
		/* TODO: RegisterProtocolNotify is not implemented yet */
		return -1;
	case BY_PROTOCOL:
		ret = efi_search_protocol(efiobj->handle, protocol, NULL);
		return (ret != EFI_SUCCESS);
	default:
		/* Invalid search type */
		return -1;
	}
}

/**
 * efi_locate_handle() - locate handles implementing a protocol
 * @search_type: selection criterion
 * @protocol:    GUID of the protocol
 * @search_key: registration key
 * @buffer_size: size of the buffer to receive the handles in bytes
 * @buffer:      buffer to receive the relevant handles
 *
 * This function is meant for U-Boot internal calls. For the API implementation
 * of the LocateHandle service see efi_locate_handle_ext.
 *
 * Return: status code
 */
static efi_status_t efi_locate_handle(
			enum efi_locate_search_type search_type,
			const efi_guid_t *protocol, void *search_key,
			efi_uintn_t *buffer_size, efi_handle_t *buffer)
{
	struct efi_object *efiobj;
	efi_uintn_t size = 0;

	/* Check parameters */
	switch (search_type) {
	case ALL_HANDLES:
		break;
	case BY_REGISTER_NOTIFY:
		if (!search_key)
			return EFI_INVALID_PARAMETER;
		/* RegisterProtocolNotify is not implemented yet */
		return EFI_UNSUPPORTED;
	case BY_PROTOCOL:
		if (!protocol)
			return EFI_INVALID_PARAMETER;
		break;
	default:
		return EFI_INVALID_PARAMETER;
	}

	/*
	 * efi_locate_handle_buffer uses this function for
	 * the calculation of the necessary buffer size.
	 * So do not require a buffer for buffersize == 0.
	 */
	if (!buffer_size || (*buffer_size && !buffer))
		return EFI_INVALID_PARAMETER;

	/* Count how much space we need */
	list_for_each_entry(efiobj, &efi_obj_list, link) {
		if (!efi_search(search_type, protocol, search_key, efiobj))
			size += sizeof(void *);
	}

	if (*buffer_size < size) {
		*buffer_size = size;
		return EFI_BUFFER_TOO_SMALL;
	}

	*buffer_size = size;
	if (size == 0)
		return EFI_NOT_FOUND;

	/* Then fill the array */
	list_for_each_entry(efiobj, &efi_obj_list, link) {
		if (!efi_search(search_type, protocol, search_key, efiobj))
			*buffer++ = efiobj->handle;
	}

	return EFI_SUCCESS;
}

/**
 * efi_locate_handle_ext() - locate handles implementing a protocol.
 * @search_type: selection criterion
 * @protocol:    GUID of the protocol
 * @search_key:  registration key
 * @buffer_size: size of the buffer to receive the handles in bytes
 * @buffer:      buffer to receive the relevant handles
 *
 * This function implements the LocateHandle service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: 0 if the handle implements the protocol
 */
static efi_status_t EFIAPI efi_locate_handle_ext(
			enum efi_locate_search_type search_type,
			const efi_guid_t *protocol, void *search_key,
			efi_uintn_t *buffer_size, efi_handle_t *buffer)
{
	EFI_ENTRY("%d, %pUl, %p, %p, %p", search_type, protocol, search_key,
		  buffer_size, buffer);

	return EFI_EXIT(efi_locate_handle(search_type, protocol, search_key,
			buffer_size, buffer));
}

/**
 * efi_remove_configuration_table() - collapses configuration table entries,
 *                                    removing index i
 *
 * @i: index of the table entry to be removed
 */
static void efi_remove_configuration_table(int i)
{
	struct efi_configuration_table *this = &efi_conf_table[i];
	struct efi_configuration_table *next = &efi_conf_table[i + 1];
	struct efi_configuration_table *end = &efi_conf_table[systab.nr_tables];

	memmove(this, next, (ulong)end - (ulong)next);
	systab.nr_tables--;
}

/**
 * efi_install_configuration_table() - adds, updates, or removes a
 *                                     configuration table
 * @guid:  GUID of the installed table
 * @table: table to be installed
 *
 * This function is used for internal calls. For the API implementation of the
 * InstallConfigurationTable service see efi_install_configuration_table_ext.
 *
 * Return: status code
 */
efi_status_t efi_install_configuration_table(const efi_guid_t *guid,
					     void *table)
{
	struct efi_event *evt;
	int i;

	if (!guid)
		return EFI_INVALID_PARAMETER;

	/* Check for guid override */
	for (i = 0; i < systab.nr_tables; i++) {
		if (!guidcmp(guid, &efi_conf_table[i].guid)) {
			if (table)
				efi_conf_table[i].table = table;
			else
				efi_remove_configuration_table(i);
			goto out;
		}
	}

	if (!table)
		return EFI_NOT_FOUND;

	/* No override, check for overflow */
	if (i >= ARRAY_SIZE(efi_conf_table))
		return EFI_OUT_OF_RESOURCES;

	/* Add a new entry */
	memcpy(&efi_conf_table[i].guid, guid, sizeof(*guid));
	efi_conf_table[i].table = table;
	systab.nr_tables = i + 1;

out:
	/* Notify that the configuration table was changed */
	list_for_each_entry(evt, &efi_events, link) {
		if (evt->group && !guidcmp(evt->group, guid)) {
			efi_signal_event(evt, false);
			break;
		}
	}

	return EFI_SUCCESS;
}

/**
 * efi_install_configuration_table_ex() - Adds, updates, or removes a
 *                                        configuration table.
 * @guid:  GUID of the installed table
 * @table: table to be installed
 *
 * This function implements the InstallConfigurationTable service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_install_configuration_table_ext(efi_guid_t *guid,
							       void *table)
{
	EFI_ENTRY("%pUl, %p", guid, table);
	return EFI_EXIT(efi_install_configuration_table(guid, table));
}

/**
 * efi_setup_loaded_image() - initialize a loaded image
 * @info:        loaded image info to be passed to the entry point of the image
 * @obj:         internal object associated with the loaded image
 * @device_path: device path of the loaded image
 * @file_path:   file path of the loaded image
 *
 * Initialize a loaded_image_info and loaded_image_info object with correct
 * protocols, boot-device, etc.
 *
 * Return: status code
 */
efi_status_t efi_setup_loaded_image(
			struct efi_loaded_image *info, struct efi_object *obj,
			struct efi_device_path *device_path,
			struct efi_device_path *file_path)
{
	efi_status_t ret;

	/* Add internal object to object list */
	efi_add_handle(obj);
	/* efi_exit() assumes that the handle points to the info */
	obj->handle = info;

	info->file_path = file_path;

	if (device_path) {
		info->device_handle = efi_dp_find_obj(device_path, NULL);
		/*
		 * When asking for the device path interface, return
		 * bootefi_device_path
		 */
		ret = efi_add_protocol(obj->handle, &efi_guid_device_path,
				       device_path);
		if (ret != EFI_SUCCESS)
			goto failure;
	}

	/*
	 * When asking for the loaded_image interface, just
	 * return handle which points to loaded_image_info
	 */
	ret = efi_add_protocol(obj->handle, &efi_guid_loaded_image, info);
	if (ret != EFI_SUCCESS)
		goto failure;

	ret = efi_add_protocol(obj->handle,
			       &efi_guid_device_path_to_text_protocol,
			       (void *)&efi_device_path_to_text);
	if (ret != EFI_SUCCESS)
		goto failure;

	ret = efi_add_protocol(obj->handle,
			       &efi_guid_device_path_utilities_protocol,
			       (void *)&efi_device_path_utilities);
	if (ret != EFI_SUCCESS)
		goto failure;

	return ret;
failure:
	printf("ERROR: Failure to install protocols for loaded image\n");
	return ret;
}

/**
 * efi_load_image_from_path() - load an image using a file path
 * @file_path: the path of the image to load
 * @buffer:    buffer containing the loaded image
 *
 * Return: status code
 */
efi_status_t efi_load_image_from_path(struct efi_device_path *file_path,
				      void **buffer)
{
	struct efi_file_info *info = NULL;
	struct efi_file_handle *f;
	static efi_status_t ret;
	efi_uintn_t bs;

	f = efi_file_from_path(file_path);
	if (!f)
		return EFI_DEVICE_ERROR;

	bs = 0;
	EFI_CALL(ret = f->getinfo(f, (efi_guid_t *)&efi_file_info_guid,
				  &bs, info));
	if (ret == EFI_BUFFER_TOO_SMALL) {
		info = malloc(bs);
		EFI_CALL(ret = f->getinfo(f, (efi_guid_t *)&efi_file_info_guid,
					  &bs, info));
	}
	if (ret != EFI_SUCCESS)
		goto error;

	ret = efi_allocate_pool(EFI_LOADER_DATA, info->file_size, buffer);
	if (ret)
		goto error;

	bs = info->file_size;
	EFI_CALL(ret = f->read(f, &bs, *buffer));

error:
	free(info);
	EFI_CALL(f->close(f));

	if (ret != EFI_SUCCESS) {
		efi_free_pool(*buffer);
		*buffer = NULL;
	}

	return ret;
}

/**
 * efi_load_image() - load an EFI image into memory
 * @boot_policy:   true for request originating from the boot manager
 * @parent_image:  the caller's image handle
 * @file_path:     the path of the image to load
 * @source_buffer: memory location from which the image is installed
 * @source_size:   size of the memory area from which the image is installed
 * @image_handle:  handle for the newly installed image
 *
 * This function implements the LoadImage service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_load_image(bool boot_policy,
					  efi_handle_t parent_image,
					  struct efi_device_path *file_path,
					  void *source_buffer,
					  efi_uintn_t source_size,
					  efi_handle_t *image_handle)
{
	struct efi_loaded_image *info;
	struct efi_object *obj;
	efi_status_t ret;

	EFI_ENTRY("%d, %p, %pD, %p, %zd, %p", boot_policy, parent_image,
		  file_path, source_buffer, source_size, image_handle);

	if (!image_handle || !parent_image) {
		ret = EFI_INVALID_PARAMETER;
		goto error;
	}

	if (!source_buffer && !file_path) {
		ret = EFI_NOT_FOUND;
		goto error;
	}

	info = calloc(1, sizeof(*info));
	if (!info) {
		ret = EFI_OUT_OF_RESOURCES;
		goto error;
	}
	obj = calloc(1, sizeof(*obj));
	if (!obj) {
		free(info);
		ret = EFI_OUT_OF_RESOURCES;
		goto error;
	}

	if (!source_buffer) {
		struct efi_device_path *dp, *fp;

		ret = efi_load_image_from_path(file_path, &source_buffer);
		if (ret != EFI_SUCCESS)
			goto failure;
		/*
		 * split file_path which contains both the device and
		 * file parts:
		 */
		efi_dp_split_file_path(file_path, &dp, &fp);
		ret = efi_setup_loaded_image(info, obj, dp, fp);
		if (ret != EFI_SUCCESS)
			goto failure;
	} else {
		/* In this case, file_path is the "device" path, ie.
		 * something like a HARDWARE_DEVICE:MEMORY_MAPPED
		 */
		ret = efi_setup_loaded_image(info, obj, file_path, NULL);
		if (ret != EFI_SUCCESS)
			goto failure;
	}
	info->reserved = efi_load_pe(source_buffer, info);
	if (!info->reserved) {
		ret = EFI_UNSUPPORTED;
		goto failure;
	}
	info->system_table = &systab;
	info->parent_handle = parent_image;
	*image_handle = obj->handle;
	return EFI_EXIT(EFI_SUCCESS);
failure:
	free(info);
	efi_delete_handle(obj);
error:
	return EFI_EXIT(ret);
}

/**
 * efi_start_image() - dall the entry point of an image
 * @image_handle:   handle of the image
 * @exit_data_size: size of the buffer
 * @exit_data:      buffer to receive the exit data of the called image
 *
 * This function implements the StartImage service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,
					   unsigned long *exit_data_size,
					   s16 **exit_data)
{
	EFIAPI efi_status_t (*entry)(efi_handle_t image_handle,
				     struct efi_system_table *st);
	struct efi_loaded_image *info = image_handle;
	efi_status_t ret;

	EFI_ENTRY("%p, %p, %p", image_handle, exit_data_size, exit_data);
	entry = info->reserved;

	efi_is_direct_boot = false;

	/* call the image! */
	if (setjmp(&info->exit_jmp)) {
		/*
		 * We called the entry point of the child image with EFI_CALL
		 * in the lines below. The child image called the Exit() boot
		 * service efi_exit() which executed the long jump that brought
		 * us to the current line. This implies that the second half
		 * of the EFI_CALL macro has not been executed.
		 */
#ifdef CONFIG_ARM
		/*
		 * efi_exit() called efi_restore_gd(). We have to undo this
		 * otherwise __efi_entry_check() will put the wrong value into
		 * app_gd.
		 */
		gd = app_gd;
#endif
		/*
		 * To get ready to call EFI_EXIT below we have to execute the
		 * missed out steps of EFI_CALL.
		 */
		assert(__efi_entry_check());
		debug("%sEFI: %lu returned by started image\n",
		      __efi_nesting_dec(),
		      (unsigned long)((uintptr_t)info->exit_status &
				      ~EFI_ERROR_MASK));
		return EFI_EXIT(info->exit_status);
	}

	ret = EFI_CALL(entry(image_handle, &systab));

	/*
	 * Usually UEFI applications call Exit() instead of returning.
	 * But because the world doesn not consist of ponies and unicorns,
	 * we're happy to emulate that behavior on behalf of a payload
	 * that forgot.
	 */
	return EFI_CALL(systab.boottime->exit(image_handle, ret, 0, NULL));
}

/**
 * efi_exit() - leave an EFI application or driver
 * @image_handle:   handle of the application or driver that is exiting
 * @exit_status:    status code
 * @exit_data_size: size of the buffer in bytes
 * @exit_data:      buffer with data describing an error
 *
 * This function implements the Exit service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
				    efi_status_t exit_status,
				    unsigned long exit_data_size,
				    int16_t *exit_data)
{
	/*
	 * We require that the handle points to the original loaded
	 * image protocol interface.
	 *
	 * For getting the longjmp address this is safer than locating
	 * the protocol because the protocol may have been reinstalled
	 * pointing to another memory location.
	 *
	 * TODO: We should call the unload procedure of the loaded
	 *	 image protocol.
	 */
	struct efi_loaded_image *loaded_image_info = (void *)image_handle;

	EFI_ENTRY("%p, %ld, %ld, %p", image_handle, exit_status,
		  exit_data_size, exit_data);

	/* Make sure entry/exit counts for EFI world cross-overs match */
	EFI_EXIT(exit_status);

	/*
	 * But longjmp out with the U-Boot gd, not the application's, as
	 * the other end is a setjmp call inside EFI context.
	 */
	efi_restore_gd();

	loaded_image_info->exit_status = exit_status;
	longjmp(&loaded_image_info->exit_jmp, 1);

	panic("EFI application exited");
}

/**
 * efi_unload_image() - unload an EFI image
 * @image_handle: handle of the image to be unloaded
 *
 * This function implements the UnloadImage service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_unload_image(efi_handle_t image_handle)
{
	struct efi_object *efiobj;

	EFI_ENTRY("%p", image_handle);
	efiobj = efi_search_obj(image_handle);
	if (efiobj)
		list_del(&efiobj->link);

	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_exit_caches() - fix up caches for EFI payloads if necessary
 */
static void efi_exit_caches(void)
{
#if defined(CONFIG_ARM) && !defined(CONFIG_ARM64)
	/*
	 * Grub on 32bit ARM needs to have caches disabled before jumping into
	 * a zImage, but does not know of all cache layers. Give it a hand.
	 */
	if (efi_is_direct_boot)
		cleanup_before_linux();
#endif
}

/**
 * efi_exit_boot_services() - stop all boot services
 * @image_handle: handle of the loaded image
 * @map_key:      key of the memory map
 *
 * This function implements the ExitBootServices service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification
 * for details.
 *
 * All timer events are disabled. For exit boot services events the
 * notification function is called. The boot services are disabled in the
 * system table.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
						  unsigned long map_key)
{
	struct efi_event *evt;

	EFI_ENTRY("%p, %ld", image_handle, map_key);

	/* Make sure that notification functions are not called anymore */
	efi_tpl = TPL_HIGH_LEVEL;

	/* Check if ExitBootServices has already been called */
	if (!systab.boottime)
		return EFI_EXIT(EFI_SUCCESS);

	/* Add related events to the event group */
	list_for_each_entry(evt, &efi_events, link) {
		if (evt->type == EVT_SIGNAL_EXIT_BOOT_SERVICES)
			evt->group = &efi_guid_event_group_exit_boot_services;
	}
	/* Notify that ExitBootServices is invoked. */
	list_for_each_entry(evt, &efi_events, link) {
		if (evt->group &&
		    !guidcmp(evt->group,
			     &efi_guid_event_group_exit_boot_services)) {
			efi_signal_event(evt, false);
			break;
		}
	}

	/* TODO Should persist EFI variables here */

	board_quiesce_devices();

	/* Fix up caches for EFI payloads if necessary */
	efi_exit_caches();

	/* This stops all lingering devices */
	bootm_disable_interrupts();

	/* Disable boottime services */
	systab.con_in_handle = NULL;
	systab.con_in = NULL;
	systab.con_out_handle = NULL;
	systab.con_out = NULL;
	systab.stderr_handle = NULL;
	systab.std_err = NULL;
	systab.boottime = NULL;

	/* Recalculate CRC32 */
	systab.hdr.crc32 = 0;
	systab.hdr.crc32 = crc32(0, (const unsigned char *)&systab,
				 sizeof(struct efi_system_table));

	/* Give the payload some time to boot */
	efi_set_watchdog(0);
	WATCHDOG_RESET();

	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_get_next_monotonic_count() - get next value of the counter
 * @count: returned value of the counter
 *
 * This function implements the NextMonotonicCount service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_get_next_monotonic_count(uint64_t *count)
{
	static uint64_t mono;

	EFI_ENTRY("%p", count);
	*count = mono++;
	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_stall() - sleep
 * @microseconds: period to sleep in microseconds
 *
 * This function implements the Stall service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return:  status code
 */
static efi_status_t EFIAPI efi_stall(unsigned long microseconds)
{
	EFI_ENTRY("%ld", microseconds);
	udelay(microseconds);
	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_set_watchdog_timer() - reset the watchdog timer
 * @timeout:       seconds before reset by watchdog
 * @watchdog_code: code to be logged when resetting
 * @data_size:     size of buffer in bytes
 * @watchdog_data: buffer with data describing the reset reason
 *
 * This function implements the SetWatchdogTimer service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_set_watchdog_timer(unsigned long timeout,
						  uint64_t watchdog_code,
						  unsigned long data_size,
						  uint16_t *watchdog_data)
{
	EFI_ENTRY("%ld, 0x%" PRIx64 ", %ld, %p", timeout, watchdog_code,
		  data_size, watchdog_data);
	return EFI_EXIT(efi_set_watchdog(timeout));
}

/**
 * efi_close_protocol() - close a protocol
 * @handle:            handle on which the protocol shall be closed
 * @protocol:          GUID of the protocol to close
 * @agent_handle:      handle of the driver
 * @controller_handle: handle of the controller
 *
 * This function implements the CloseProtocol service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_close_protocol(efi_handle_t handle,
					      const efi_guid_t *protocol,
					      efi_handle_t agent_handle,
					      efi_handle_t controller_handle)
{
	struct efi_handler *handler;
	struct efi_open_protocol_info_item *item;
	struct efi_open_protocol_info_item *pos;
	efi_status_t r;

	EFI_ENTRY("%p, %pUl, %p, %p", handle, protocol, agent_handle,
		  controller_handle);

	if (!agent_handle) {
		r = EFI_INVALID_PARAMETER;
		goto out;
	}
	r = efi_search_protocol(handle, protocol, &handler);
	if (r != EFI_SUCCESS)
		goto out;

	r = EFI_NOT_FOUND;
	list_for_each_entry_safe(item, pos, &handler->open_infos, link) {
		if (item->info.agent_handle == agent_handle &&
		    item->info.controller_handle == controller_handle) {
			efi_delete_open_info(item);
			r = EFI_SUCCESS;
			break;
		}
	}
out:
	return EFI_EXIT(r);
}

/**
 * efi_open_protocol_information() - provide information about then open status
 *                                   of a protocol on a handle
 * @handle:       handle for which the information shall be retrieved
 * @protocol:     GUID of the protocol
 * @entry_buffer: buffer to receive the open protocol information
 * @entry_count:  number of entries available in the buffer
 *
 * This function implements the OpenProtocolInformation service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_open_protocol_information(
			efi_handle_t handle, const efi_guid_t *protocol,
			struct efi_open_protocol_info_entry **entry_buffer,
			efi_uintn_t *entry_count)
{
	unsigned long buffer_size;
	unsigned long count;
	struct efi_handler *handler;
	struct efi_open_protocol_info_item *item;
	efi_status_t r;

	EFI_ENTRY("%p, %pUl, %p, %p", handle, protocol, entry_buffer,
		  entry_count);

	/* Check parameters */
	if (!entry_buffer) {
		r = EFI_INVALID_PARAMETER;
		goto out;
	}
	r = efi_search_protocol(handle, protocol, &handler);
	if (r != EFI_SUCCESS)
		goto out;

	/* Count entries */
	count = 0;
	list_for_each_entry(item, &handler->open_infos, link) {
		if (item->info.open_count)
			++count;
	}
	*entry_count = count;
	*entry_buffer = NULL;
	if (!count) {
		r = EFI_SUCCESS;
		goto out;
	}

	/* Copy entries */
	buffer_size = count * sizeof(struct efi_open_protocol_info_entry);
	r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, buffer_size,
			      (void **)entry_buffer);
	if (r != EFI_SUCCESS)
		goto out;
	list_for_each_entry_reverse(item, &handler->open_infos, link) {
		if (item->info.open_count)
			(*entry_buffer)[--count] = item->info;
	}
out:
	return EFI_EXIT(r);
}

/**
 * efi_protocols_per_handle() - get protocols installed on a handle
 * @handle:                handle for which the information is retrieved
 * @protocol_buffer:       buffer with protocol GUIDs
 * @protocol_buffer_count: number of entries in the buffer
 *
 * This function implements the ProtocolsPerHandleService.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_protocols_per_handle(
			efi_handle_t handle, efi_guid_t ***protocol_buffer,
			efi_uintn_t *protocol_buffer_count)
{
	unsigned long buffer_size;
	struct efi_object *efiobj;
	struct list_head *protocol_handle;
	efi_status_t r;

	EFI_ENTRY("%p, %p, %p", handle, protocol_buffer,
		  protocol_buffer_count);

	if (!handle || !protocol_buffer || !protocol_buffer_count)
		return EFI_EXIT(EFI_INVALID_PARAMETER);

	*protocol_buffer = NULL;
	*protocol_buffer_count = 0;

	efiobj = efi_search_obj(handle);
	if (!efiobj)
		return EFI_EXIT(EFI_INVALID_PARAMETER);

	/* Count protocols */
	list_for_each(protocol_handle, &efiobj->protocols) {
		++*protocol_buffer_count;
	}

	/* Copy guids */
	if (*protocol_buffer_count) {
		size_t j = 0;

		buffer_size = sizeof(efi_guid_t *) * *protocol_buffer_count;
		r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, buffer_size,
				      (void **)protocol_buffer);
		if (r != EFI_SUCCESS)
			return EFI_EXIT(r);
		list_for_each(protocol_handle, &efiobj->protocols) {
			struct efi_handler *protocol;

			protocol = list_entry(protocol_handle,
					      struct efi_handler, link);
			(*protocol_buffer)[j] = (void *)protocol->guid;
			++j;
		}
	}

	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_locate_handle_buffer() - locate handles implementing a protocol
 * @search_type: selection criterion
 * @protocol:    GUID of the protocol
 * @search_key:  registration key
 * @no_handles:  number of returned handles
 * @buffer:      buffer with the returned handles
 *
 * This function implements the LocateHandleBuffer service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_locate_handle_buffer(
			enum efi_locate_search_type search_type,
			const efi_guid_t *protocol, void *search_key,
			efi_uintn_t *no_handles, efi_handle_t **buffer)
{
	efi_status_t r;
	efi_uintn_t buffer_size = 0;

	EFI_ENTRY("%d, %pUl, %p, %p, %p", search_type, protocol, search_key,
		  no_handles, buffer);

	if (!no_handles || !buffer) {
		r = EFI_INVALID_PARAMETER;
		goto out;
	}
	*no_handles = 0;
	*buffer = NULL;
	r = efi_locate_handle(search_type, protocol, search_key, &buffer_size,
			      *buffer);
	if (r != EFI_BUFFER_TOO_SMALL)
		goto out;
	r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, buffer_size,
			      (void **)buffer);
	if (r != EFI_SUCCESS)
		goto out;
	r = efi_locate_handle(search_type, protocol, search_key, &buffer_size,
			      *buffer);
	if (r == EFI_SUCCESS)
		*no_handles = buffer_size / sizeof(efi_handle_t);
out:
	return EFI_EXIT(r);
}

/**
 * efi_locate_protocol() - find an interface implementing a protocol
 * @protocol:           GUID of the protocol
 * @registration:       registration key passed to the notification function
 * @protocol_interface: interface implementing the protocol
 *
 * This function implements the LocateProtocol service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_locate_protocol(const efi_guid_t *protocol,
					       void *registration,
					       void **protocol_interface)
{
	struct list_head *lhandle;
	efi_status_t ret;

	EFI_ENTRY("%pUl, %p, %p", protocol, registration, protocol_interface);

	if (!protocol || !protocol_interface)
		return EFI_EXIT(EFI_INVALID_PARAMETER);

	list_for_each(lhandle, &efi_obj_list) {
		struct efi_object *efiobj;
		struct efi_handler *handler;

		efiobj = list_entry(lhandle, struct efi_object, link);

		ret = efi_search_protocol(efiobj->handle, protocol, &handler);
		if (ret == EFI_SUCCESS) {
			*protocol_interface = handler->protocol_interface;
			return EFI_EXIT(EFI_SUCCESS);
		}
	}
	*protocol_interface = NULL;

	return EFI_EXIT(EFI_NOT_FOUND);
}

/**
 * efi_locate_device_path() - Get the device path and handle of an device
 *                            implementing a protocol
 * @protocol:    GUID of the protocol
 * @device_path: device path
 * @device:      handle of the device
 *
 * This function implements the LocateDevicePath service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_locate_device_path(
			const efi_guid_t *protocol,
			struct efi_device_path **device_path,
			efi_handle_t *device)
{
	struct efi_device_path *dp;
	size_t i;
	struct efi_handler *handler;
	efi_handle_t *handles;
	size_t len, len_dp;
	size_t len_best = 0;
	efi_uintn_t no_handles;
	u8 *remainder;
	efi_status_t ret;

	EFI_ENTRY("%pUl, %p, %p", protocol, device_path, device);

	if (!protocol || !device_path || !*device_path || !device) {
		ret = EFI_INVALID_PARAMETER;
		goto out;
	}

	/* Find end of device path */
	len = efi_dp_instance_size(*device_path);

	/* Get all handles implementing the protocol */
	ret = EFI_CALL(efi_locate_handle_buffer(BY_PROTOCOL, protocol, NULL,
						&no_handles, &handles));
	if (ret != EFI_SUCCESS)
		goto out;

	for (i = 0; i < no_handles; ++i) {
		/* Find the device path protocol */
		ret = efi_search_protocol(handles[i], &efi_guid_device_path,
					  &handler);
		if (ret != EFI_SUCCESS)
			continue;
		dp = (struct efi_device_path *)handler->protocol_interface;
		len_dp = efi_dp_instance_size(dp);
		/*
		 * This handle can only be a better fit
		 * if its device path length is longer than the best fit and
		 * if its device path length is shorter of equal the searched
		 * device path.
		 */
		if (len_dp <= len_best || len_dp > len)
			continue;
		/* Check if dp is a subpath of device_path */
		if (memcmp(*device_path, dp, len_dp))
			continue;
		*device = handles[i];
		len_best = len_dp;
	}
	if (len_best) {
		remainder = (u8 *)*device_path + len_best;
		*device_path = (struct efi_device_path *)remainder;
		ret = EFI_SUCCESS;
	} else {
		ret = EFI_NOT_FOUND;
	}
out:
	return EFI_EXIT(ret);
}

/**
 * efi_install_multiple_protocol_interfaces() - Install multiple protocol
 *                                              interfaces
 * @handle: handle on which the protocol interfaces shall be installed
 * @...:    NULL terminated argument list with pairs of protocol GUIDS and
 *          interfaces
 *
 * This function implements the MultipleProtocolInterfaces service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_install_multiple_protocol_interfaces(
			void **handle, ...)
{
	EFI_ENTRY("%p", handle);

	efi_va_list argptr;
	const efi_guid_t *protocol;
	void *protocol_interface;
	efi_status_t r = EFI_SUCCESS;
	int i = 0;

	if (!handle)
		return EFI_EXIT(EFI_INVALID_PARAMETER);

	efi_va_start(argptr, handle);
	for (;;) {
		protocol = efi_va_arg(argptr, efi_guid_t*);
		if (!protocol)
			break;
		protocol_interface = efi_va_arg(argptr, void*);
		r = EFI_CALL(efi_install_protocol_interface(
						handle, protocol,
						EFI_NATIVE_INTERFACE,
						protocol_interface));
		if (r != EFI_SUCCESS)
			break;
		i++;
	}
	efi_va_end(argptr);
	if (r == EFI_SUCCESS)
		return EFI_EXIT(r);

	/* If an error occurred undo all changes. */
	efi_va_start(argptr, handle);
	for (; i; --i) {
		protocol = efi_va_arg(argptr, efi_guid_t*);
		protocol_interface = efi_va_arg(argptr, void*);
		EFI_CALL(efi_uninstall_protocol_interface(handle, protocol,
							  protocol_interface));
	}
	efi_va_end(argptr);

	return EFI_EXIT(r);
}

/**
 * efi_uninstall_multiple_protocol_interfaces() - uninstall multiple protocol
 *                                                interfaces
 * @handle: handle from which the protocol interfaces shall be removed
 * @...:    NULL terminated argument list with pairs of protocol GUIDS and
 *          interfaces
 *
 * This function implements the UninstallMultipleProtocolInterfaces service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_uninstall_multiple_protocol_interfaces(
			void *handle, ...)
{
	EFI_ENTRY("%p", handle);

	efi_va_list argptr;
	const efi_guid_t *protocol;
	void *protocol_interface;
	efi_status_t r = EFI_SUCCESS;
	size_t i = 0;

	if (!handle)
		return EFI_EXIT(EFI_INVALID_PARAMETER);

	efi_va_start(argptr, handle);
	for (;;) {
		protocol = efi_va_arg(argptr, efi_guid_t*);
		if (!protocol)
			break;
		protocol_interface = efi_va_arg(argptr, void*);
		r = EFI_CALL(efi_uninstall_protocol_interface(
						handle, protocol,
						protocol_interface));
		if (r != EFI_SUCCESS)
			break;
		i++;
	}
	efi_va_end(argptr);
	if (r == EFI_SUCCESS)
		return EFI_EXIT(r);

	/* If an error occurred undo all changes. */
	efi_va_start(argptr, handle);
	for (; i; --i) {
		protocol = efi_va_arg(argptr, efi_guid_t*);
		protocol_interface = efi_va_arg(argptr, void*);
		EFI_CALL(efi_install_protocol_interface(&handle, protocol,
							EFI_NATIVE_INTERFACE,
							protocol_interface));
	}
	efi_va_end(argptr);

	return EFI_EXIT(r);
}

/**
 * efi_calculate_crc32() - calculate cyclic redundancy code
 * @data:      buffer with data
 * @data_size: size of buffer in bytes
 * @crc32_p:   cyclic redundancy code
 *
 * This function implements the CalculateCrc32 service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_calculate_crc32(void *data,
					       unsigned long data_size,
					       uint32_t *crc32_p)
{
	EFI_ENTRY("%p, %ld", data, data_size);
	*crc32_p = crc32(0, data, data_size);
	return EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_copy_mem() - copy memory
 * @destination: destination of the copy operation
 * @source:      source of the copy operation
 * @length:      number of bytes to copy
 *
 * This function implements the CopyMem service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 */
static void EFIAPI efi_copy_mem(void *destination, const void *source,
				size_t length)
{
	EFI_ENTRY("%p, %p, %ld", destination, source, (unsigned long)length);
	memcpy(destination, source, length);
	EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_set_mem() - Fill memory with a byte value.
 * @buffer: buffer to fill
 * @size:   size of buffer in bytes
 * @value:  byte to copy to the buffer
 *
 * This function implements the SetMem service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 */
static void EFIAPI efi_set_mem(void *buffer, size_t size, uint8_t value)
{
	EFI_ENTRY("%p, %ld, 0x%x", buffer, (unsigned long)size, value);
	memset(buffer, value, size);
	EFI_EXIT(EFI_SUCCESS);
}

/**
 * efi_protocol_open() - open protocol interface on a handle
 * @handler:            handler of a protocol
 * @protocol_interface: interface implementing the protocol
 * @agent_handle:       handle of the driver
 * @controller_handle:  handle of the controller
 * @attributes:         attributes indicating how to open the protocol
 *
 * Return: status code
 */
static efi_status_t efi_protocol_open(
			struct efi_handler *handler,
			void **protocol_interface, void *agent_handle,
			void *controller_handle, uint32_t attributes)
{
	struct efi_open_protocol_info_item *item;
	struct efi_open_protocol_info_entry *match = NULL;
	bool opened_by_driver = false;
	bool opened_exclusive = false;

	/* If there is no agent, only return the interface */
	if (!agent_handle)
		goto out;

	/* For TEST_PROTOCOL ignore interface attribute */
	if (attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
		*protocol_interface = NULL;

	/*
	 * Check if the protocol is already opened by a driver with the same
	 * attributes or opened exclusively
	 */
	list_for_each_entry(item, &handler->open_infos, link) {
		if (item->info.agent_handle == agent_handle) {
			if ((attributes & EFI_OPEN_PROTOCOL_BY_DRIVER) &&
			    (item->info.attributes == attributes))
				return EFI_ALREADY_STARTED;
		}
		if (item->info.attributes & EFI_OPEN_PROTOCOL_EXCLUSIVE)
			opened_exclusive = true;
	}

	/* Only one controller can open the protocol exclusively */
	if (opened_exclusive && attributes &
	    (EFI_OPEN_PROTOCOL_EXCLUSIVE | EFI_OPEN_PROTOCOL_BY_DRIVER))
		return EFI_ACCESS_DENIED;

	/* Prepare exclusive opening */
	if (attributes & EFI_OPEN_PROTOCOL_EXCLUSIVE) {
		/* Try to disconnect controllers */
		list_for_each_entry(item, &handler->open_infos, link) {
			if (item->info.attributes ==
					EFI_OPEN_PROTOCOL_BY_DRIVER)
				EFI_CALL(efi_disconnect_controller(
						item->info.controller_handle,
						item->info.agent_handle,
						NULL));
		}
		opened_by_driver = false;
		/* Check if all controllers are disconnected */
		list_for_each_entry(item, &handler->open_infos, link) {
			if (item->info.attributes & EFI_OPEN_PROTOCOL_BY_DRIVER)
				opened_by_driver = true;
		}
		/* Only one controller can be conncected */
		if (opened_by_driver)
			return EFI_ACCESS_DENIED;
	}

	/* Find existing entry */
	list_for_each_entry(item, &handler->open_infos, link) {
		if (item->info.agent_handle == agent_handle &&
		    item->info.controller_handle == controller_handle)
			match = &item->info;
	}
	/* None found, create one */
	if (!match) {
		match = efi_create_open_info(handler);
		if (!match)
			return EFI_OUT_OF_RESOURCES;
	}

	match->agent_handle = agent_handle;
	match->controller_handle = controller_handle;
	match->attributes = attributes;
	match->open_count++;

out:
	/* For TEST_PROTOCOL ignore interface attribute. */
	if (attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL)
		*protocol_interface = handler->protocol_interface;

	return EFI_SUCCESS;
}

/**
 * efi_open_protocol() - open protocol interface on a handle
 * @handle:             handle on which the protocol shall be opened
 * @protocol:           GUID of the protocol
 * @protocol_interface: interface implementing the protocol
 * @agent_handle:       handle of the driver
 * @controller_handle:  handle of the controller
 * @attributes:         attributes indicating how to open the protocol
 *
 * This function implements the OpenProtocol interface.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_open_protocol(
			void *handle, const efi_guid_t *protocol,
			void **protocol_interface, void *agent_handle,
			void *controller_handle, uint32_t attributes)
{
	struct efi_handler *handler;
	efi_status_t r = EFI_INVALID_PARAMETER;

	EFI_ENTRY("%p, %pUl, %p, %p, %p, 0x%x", handle, protocol,
		  protocol_interface, agent_handle, controller_handle,
		  attributes);

	if (!handle || !protocol ||
	    (!protocol_interface && attributes !=
	     EFI_OPEN_PROTOCOL_TEST_PROTOCOL)) {
		goto out;
	}

	switch (attributes) {
	case EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL:
	case EFI_OPEN_PROTOCOL_GET_PROTOCOL:
	case EFI_OPEN_PROTOCOL_TEST_PROTOCOL:
		break;
	case EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER:
		if (controller_handle == handle)
			goto out;
		/* fall-through */
	case EFI_OPEN_PROTOCOL_BY_DRIVER:
	case EFI_OPEN_PROTOCOL_BY_DRIVER | EFI_OPEN_PROTOCOL_EXCLUSIVE:
		/* Check that the controller handle is valid */
		if (!efi_search_obj(controller_handle))
			goto out;
		/* fall-through */
	case EFI_OPEN_PROTOCOL_EXCLUSIVE:
		/* Check that the agent handle is valid */
		if (!efi_search_obj(agent_handle))
			goto out;
		break;
	default:
		goto out;
	}

	r = efi_search_protocol(handle, protocol, &handler);
	if (r != EFI_SUCCESS)
		goto out;

	r = efi_protocol_open(handler, protocol_interface, agent_handle,
			      controller_handle, attributes);
out:
	return EFI_EXIT(r);
}

/**
 * efi_handle_protocol() - get interface of a protocol on a handle
 * @handle:             handle on which the protocol shall be opened
 * @protocol:           GUID of the protocol
 * @protocol_interface: interface implementing the protocol
 *
 * This function implements the HandleProtocol service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_handle_protocol(efi_handle_t handle,
					       const efi_guid_t *protocol,
					       void **protocol_interface)
{
	return efi_open_protocol(handle, protocol, protocol_interface, NULL,
				 NULL, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
}

/**
 * efi_bind_controller() - bind a single driver to a controller
 * @controller_handle:   controller handle
 * @driver_image_handle: driver handle
 * @remain_device_path:  remaining path
 *
 * Return: status code
 */
static efi_status_t efi_bind_controller(
			efi_handle_t controller_handle,
			efi_handle_t driver_image_handle,
			struct efi_device_path *remain_device_path)
{
	struct efi_driver_binding_protocol *binding_protocol;
	efi_status_t r;

	r = EFI_CALL(efi_open_protocol(driver_image_handle,
				       &efi_guid_driver_binding_protocol,
				       (void **)&binding_protocol,
				       driver_image_handle, NULL,
				       EFI_OPEN_PROTOCOL_GET_PROTOCOL));
	if (r != EFI_SUCCESS)
		return r;
	r = EFI_CALL(binding_protocol->supported(binding_protocol,
						 controller_handle,
						 remain_device_path));
	if (r == EFI_SUCCESS)
		r = EFI_CALL(binding_protocol->start(binding_protocol,
						     controller_handle,
						     remain_device_path));
	EFI_CALL(efi_close_protocol(driver_image_handle,
				    &efi_guid_driver_binding_protocol,
				    driver_image_handle, NULL));
	return r;
}

/**
 * efi_connect_single_controller() - connect a single driver to a controller
 * @controller_handle:   controller
 * @driver_image_handle: driver
 * @remain_device_path:  remainting path
 *
 * Return: status code
 */
static efi_status_t efi_connect_single_controller(
			efi_handle_t controller_handle,
			efi_handle_t *driver_image_handle,
			struct efi_device_path *remain_device_path)
{
	efi_handle_t *buffer;
	size_t count;
	size_t i;
	efi_status_t r;
	size_t connected = 0;

	/* Get buffer with all handles with driver binding protocol */
	r = EFI_CALL(efi_locate_handle_buffer(BY_PROTOCOL,
					      &efi_guid_driver_binding_protocol,
					      NULL, &count, &buffer));
	if (r != EFI_SUCCESS)
		return r;

	/*  Context Override */
	if (driver_image_handle) {
		for (; *driver_image_handle; ++driver_image_handle) {
			for (i = 0; i < count; ++i) {
				if (buffer[i] == *driver_image_handle) {
					buffer[i] = NULL;
					r = efi_bind_controller(
							controller_handle,
							*driver_image_handle,
							remain_device_path);
					/*
					 * For drivers that do not support the
					 * controller or are already connected
					 * we receive an error code here.
					 */
					if (r == EFI_SUCCESS)
						++connected;
				}
			}
		}
	}

	/*
	 * TODO: Some overrides are not yet implemented:
	 * - Platform Driver Override
	 * - Driver Family Override Search
	 * - Bus Specific Driver Override
	 */

	/* Driver Binding Search */
	for (i = 0; i < count; ++i) {
		if (buffer[i]) {
			r = efi_bind_controller(controller_handle,
						buffer[i],
						remain_device_path);
			if (r == EFI_SUCCESS)
				++connected;
		}
	}

	efi_free_pool(buffer);
	if (!connected)
		return EFI_NOT_FOUND;
	return EFI_SUCCESS;
}

/**
 * efi_connect_controller() - connect a controller to a driver
 * @controller_handle:   handle of the controller
 * @driver_image_handle: handle of the driver
 * @remain_device_path:  device path of a child controller
 * @recursive:           true to connect all child controllers
 *
 * This function implements the ConnectController service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * First all driver binding protocol handles are tried for binding drivers.
 * Afterwards all handles that have openened a protocol of the controller
 * with EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER are connected to drivers.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_connect_controller(
			efi_handle_t controller_handle,
			efi_handle_t *driver_image_handle,
			struct efi_device_path *remain_device_path,
			bool recursive)
{
	efi_status_t r;
	efi_status_t ret = EFI_NOT_FOUND;
	struct efi_object *efiobj;

	EFI_ENTRY("%p, %p, %p, %d", controller_handle, driver_image_handle,
		  remain_device_path, recursive);

	efiobj = efi_search_obj(controller_handle);
	if (!efiobj) {
		ret = EFI_INVALID_PARAMETER;
		goto out;
	}

	r = efi_connect_single_controller(controller_handle,
					  driver_image_handle,
					  remain_device_path);
	if (r == EFI_SUCCESS)
		ret = EFI_SUCCESS;
	if (recursive) {
		struct efi_handler *handler;
		struct efi_open_protocol_info_item *item;

		list_for_each_entry(handler, &efiobj->protocols, link) {
			list_for_each_entry(item, &handler->open_infos, link) {
				if (item->info.attributes &
				    EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER) {
					r = EFI_CALL(efi_connect_controller(
						item->info.controller_handle,
						driver_image_handle,
						remain_device_path,
						recursive));
					if (r == EFI_SUCCESS)
						ret = EFI_SUCCESS;
				}
			}
		}
	}
	/*  Check for child controller specified by end node */
	if (ret != EFI_SUCCESS && remain_device_path &&
	    remain_device_path->type == DEVICE_PATH_TYPE_END)
		ret = EFI_SUCCESS;
out:
	return EFI_EXIT(ret);
}

/**
 * efi_reinstall_protocol_interface() - reinstall protocol interface
 * @handle:        handle on which the protocol shall be reinstalled
 * @protocol:      GUID of the protocol to be installed
 * @old_interface: interface to be removed
 * @new_interface: interface to be installed
 *
 * This function implements the ReinstallProtocolInterface service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * The old interface is uninstalled. The new interface is installed.
 * Drivers are connected.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_reinstall_protocol_interface(
			efi_handle_t handle, const efi_guid_t *protocol,
			void *old_interface, void *new_interface)
{
	efi_status_t ret;

	EFI_ENTRY("%p, %pUl, %p, %p", handle, protocol, old_interface,
		  new_interface);
	ret = EFI_CALL(efi_uninstall_protocol_interface(handle, protocol,
							old_interface));
	if (ret != EFI_SUCCESS)
		goto out;
	ret = EFI_CALL(efi_install_protocol_interface(&handle, protocol,
						      EFI_NATIVE_INTERFACE,
						      new_interface));
	if (ret != EFI_SUCCESS)
		goto out;
	/*
	 * The returned status code has to be ignored.
	 * Do not create an error if no suitable driver for the handle exists.
	 */
	EFI_CALL(efi_connect_controller(handle, NULL, NULL, true));
out:
	return EFI_EXIT(ret);
}

/**
 * efi_get_child_controllers() - get all child controllers associated to a driver
 * @efiobj:              handle of the controller
 * @driver_handle:       handle of the driver
 * @number_of_children:  number of child controllers
 * @child_handle_buffer: handles of the the child controllers
 *
 * The allocated buffer has to be freed with free().
 *
 * Return: status code
 */
static efi_status_t efi_get_child_controllers(
				struct efi_object *efiobj,
				efi_handle_t driver_handle,
				efi_uintn_t *number_of_children,
				efi_handle_t **child_handle_buffer)
{
	struct efi_handler *handler;
	struct efi_open_protocol_info_item *item;
	efi_uintn_t count = 0, i;
	bool duplicate;

	/* Count all child controller associations */
	list_for_each_entry(handler, &efiobj->protocols, link) {
		list_for_each_entry(item, &handler->open_infos, link) {
			if (item->info.agent_handle == driver_handle &&
			    item->info.attributes &
			    EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER)
				++count;
		}
	}
	/*
	 * Create buffer. In case of duplicate child controller assignments
	 * the buffer will be too large. But that does not harm.
	 */
	*number_of_children = 0;
	*child_handle_buffer = calloc(count, sizeof(efi_handle_t));
	if (!*child_handle_buffer)
		return EFI_OUT_OF_RESOURCES;
	/* Copy unique child handles */
	list_for_each_entry(handler, &efiobj->protocols, link) {
		list_for_each_entry(item, &handler->open_infos, link) {
			if (item->info.agent_handle == driver_handle &&
			    item->info.attributes &
			    EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER) {
				/* Check this is a new child controller */
				duplicate = false;
				for (i = 0; i < *number_of_children; ++i) {
					if ((*child_handle_buffer)[i] ==
					    item->info.controller_handle)
						duplicate = true;
				}
				/* Copy handle to buffer */
				if (!duplicate) {
					i = (*number_of_children)++;
					(*child_handle_buffer)[i] =
						item->info.controller_handle;
				}
			}
		}
	}
	return EFI_SUCCESS;
}

/**
 * efi_disconnect_controller() - disconnect a controller from a driver
 * @controller_handle:   handle of the controller
 * @driver_image_handle: handle of the driver
 * @child_handle:        handle of the child to destroy
 *
 * This function implements the DisconnectController service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * Return: status code
 */
static efi_status_t EFIAPI efi_disconnect_controller(
				efi_handle_t controller_handle,
				efi_handle_t driver_image_handle,
				efi_handle_t child_handle)
{
	struct efi_driver_binding_protocol *binding_protocol;
	efi_handle_t *child_handle_buffer = NULL;
	size_t number_of_children = 0;
	efi_status_t r;
	size_t stop_count = 0;
	struct efi_object *efiobj;

	EFI_ENTRY("%p, %p, %p", controller_handle, driver_image_handle,
		  child_handle);

	efiobj = efi_search_obj(controller_handle);
	if (!efiobj) {
		r = EFI_INVALID_PARAMETER;
		goto out;
	}

	if (child_handle && !efi_search_obj(child_handle)) {
		r = EFI_INVALID_PARAMETER;
		goto out;
	}

	/* If no driver handle is supplied, disconnect all drivers */
	if (!driver_image_handle) {
		r = efi_disconnect_all_drivers(efiobj, NULL, child_handle);
		goto out;
	}

	/* Create list of child handles */
	if (child_handle) {
		number_of_children = 1;
		child_handle_buffer = &child_handle;
	} else {
		efi_get_child_controllers(efiobj,
					  driver_image_handle,
					  &number_of_children,
					  &child_handle_buffer);
	}

	/* Get the driver binding protocol */
	r = EFI_CALL(efi_open_protocol(driver_image_handle,
				       &efi_guid_driver_binding_protocol,
				       (void **)&binding_protocol,
				       driver_image_handle, NULL,
				       EFI_OPEN_PROTOCOL_GET_PROTOCOL));
	if (r != EFI_SUCCESS)
		goto out;
	/* Remove the children */
	if (number_of_children) {
		r = EFI_CALL(binding_protocol->stop(binding_protocol,
						    controller_handle,
						    number_of_children,
						    child_handle_buffer));
		if (r == EFI_SUCCESS)
			++stop_count;
	}
	/* Remove the driver */
	if (!child_handle)
		r = EFI_CALL(binding_protocol->stop(binding_protocol,
						    controller_handle,
						    0, NULL));
	if (r == EFI_SUCCESS)
		++stop_count;
	EFI_CALL(efi_close_protocol(driver_image_handle,
				    &efi_guid_driver_binding_protocol,
				    driver_image_handle, NULL));

	if (stop_count)
		r = EFI_SUCCESS;
	else
		r = EFI_NOT_FOUND;
out:
	if (!child_handle)
		free(child_handle_buffer);
	return EFI_EXIT(r);
}

static const struct efi_boot_services efi_boot_services = {
	.hdr = {
		.headersize = sizeof(struct efi_table_hdr),
	},
	.raise_tpl = efi_raise_tpl,
	.restore_tpl = efi_restore_tpl,
	.allocate_pages = efi_allocate_pages_ext,
	.free_pages = efi_free_pages_ext,
	.get_memory_map = efi_get_memory_map_ext,
	.allocate_pool = efi_allocate_pool_ext,
	.free_pool = efi_free_pool_ext,
	.create_event = efi_create_event_ext,
	.set_timer = efi_set_timer_ext,
	.wait_for_event = efi_wait_for_event,
	.signal_event = efi_signal_event_ext,
	.close_event = efi_close_event,
	.check_event = efi_check_event,
	.install_protocol_interface = efi_install_protocol_interface,
	.reinstall_protocol_interface = efi_reinstall_protocol_interface,
	.uninstall_protocol_interface = efi_uninstall_protocol_interface,
	.handle_protocol = efi_handle_protocol,
	.reserved = NULL,
	.register_protocol_notify = efi_register_protocol_notify,
	.locate_handle = efi_locate_handle_ext,
	.locate_device_path = efi_locate_device_path,
	.install_configuration_table = efi_install_configuration_table_ext,
	.load_image = efi_load_image,
	.start_image = efi_start_image,
	.exit = efi_exit,
	.unload_image = efi_unload_image,
	.exit_boot_services = efi_exit_boot_services,
	.get_next_monotonic_count = efi_get_next_monotonic_count,
	.stall = efi_stall,
	.set_watchdog_timer = efi_set_watchdog_timer,
	.connect_controller = efi_connect_controller,
	.disconnect_controller = efi_disconnect_controller,
	.open_protocol = efi_open_protocol,
	.close_protocol = efi_close_protocol,
	.open_protocol_information = efi_open_protocol_information,
	.protocols_per_handle = efi_protocols_per_handle,
	.locate_handle_buffer = efi_locate_handle_buffer,
	.locate_protocol = efi_locate_protocol,
	.install_multiple_protocol_interfaces =
			efi_install_multiple_protocol_interfaces,
	.uninstall_multiple_protocol_interfaces =
			efi_uninstall_multiple_protocol_interfaces,
	.calculate_crc32 = efi_calculate_crc32,
	.copy_mem = efi_copy_mem,
	.set_mem = efi_set_mem,
	.create_event_ex = efi_create_event_ex,
};

static uint16_t __efi_runtime_data firmware_vendor[] = L"Das U-Boot";

struct efi_system_table __efi_runtime_data systab = {
	.hdr = {
		.signature = EFI_SYSTEM_TABLE_SIGNATURE,
		.revision = 2 << 16 | 70, /* 2.7 */
		.headersize = sizeof(struct efi_table_hdr),
	},
	.fw_vendor = (long)firmware_vendor,
	.con_in = (void *)&efi_con_in,
	.con_out = (void *)&efi_con_out,
	.std_err = (void *)&efi_con_out,
	.runtime = (void *)&efi_runtime_services,
	.boottime = (void *)&efi_boot_services,
	.nr_tables = 0,
	.tables = (void *)efi_conf_table,
};