/*
   *  EFI application boot time services
   *
   *  Copyright (c) 2016 Alexander Graf
   *
   *  SPDX-License-Identifier:     GPL-2.0+
   */
  
  #include <common.h>
  #include <div64.h>
  #include <efi_loader.h>
  #include <environment.h>
  #include <malloc.h>
  #include <asm/global_data.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);
  
  /*
   * 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[2];
  
  #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 EFI_DRIVER_BINDING_PROTOCOL */
  const efi_guid_t efi_guid_driver_binding_protocol =
  			EFI_DRIVER_BINDING_PROTOCOL_GUID;
  
  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
  }
  
  /*
   * Return a string for indenting with two spaces per level. A maximum of ten
   * indent levels is supported. Higher indent levels will be truncated.
   *
   * @level	indent level
   * @return	indent string
   */
  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);
  }
  
  /*
   * Queue an EFI event.
   *
   * 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.
   *
   * @event	event to signal
   * @check_tpl	check the TPL level
   */
  void efi_signal_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;
  }
  
  /*
   * Raise the task priority level.
   *
   * This function implements the RaiseTpl service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @new_tpl	new value of the task priority level
   * @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
  ", __func__);
  	efi_tpl = new_tpl;
  	if (efi_tpl > TPL_HIGH_LEVEL)
  		efi_tpl = TPL_HIGH_LEVEL;
  
  	EFI_EXIT(EFI_SUCCESS);
  	return old_tpl;
  }
  
  /*
   * Lower the task priority level.
   *
   * This function implements the RestoreTpl service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @old_tpl	value of the task priority level to be restored
   */
  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
  ", __func__);
  	efi_tpl = old_tpl;
  	if (efi_tpl > TPL_HIGH_LEVEL)
  		efi_tpl = TPL_HIGH_LEVEL;
  
  	EFI_EXIT(EFI_SUCCESS);
  }
  
  /*
   * Allocate memory pages.
   *
   * This function implements the AllocatePages service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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);
  }
  
  /*
   * Free memory pages.
   *
   * This function implements the FreePages service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @memory	start of the memory area to be freed
   * @pages	number of pages to be freed
   * @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);
  }
  
  /*
   * Get map describing memory usage.
   *
   * This function implements the GetMemoryMap service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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);
  }
  
  /*
   * Allocate memory from pool.
   *
   * This function implements the AllocatePool service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @pool_type	type of the pool from which memory is to be allocated
   * @size	number of bytes to be allocated
   * @buffer	allocated memory
   * @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);
  }
  
  /*
   * Free memory from pool.
   *
   * This function implements the FreePool service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @buffer	start of memory to be freed
   * @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);
  }
  
  /*
   * Add a new object to the object list.
   *
   * The protocols list is initialized.
   * The object handle is set.
   *
   * @obj	object to be added
   */
  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);
  }
  
  /*
   * Create handle.
   *
   * @handle	new handle
   * @return	status code
   */
  efi_status_t efi_create_handle(efi_handle_t *handle)
  {
  	struct efi_object *obj;
  	efi_status_t r;
  
  	r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES,
  			      sizeof(struct efi_object),
  			      (void **)&obj);
  	if (r != EFI_SUCCESS)
  		return r;
  	efi_add_handle(obj);
  	*handle = obj->handle;
  	return r;
  }
  
  /*
   * 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;
  }
  
  /*
   * 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;
  	list_del(&handler->link);
  	free(handler);
  	return EFI_SUCCESS;
  }
  
  /*
   * 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;
  }
  
  /*
   * Delete handle.
   *
   * @handle	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);
  }
  
  /*
   * Our event capabilities are very limited. Only a small limited
   * number of events is allowed to coexist.
   */
  static struct efi_event efi_events[16];
  
  /*
   * Create an 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.
   *
   * @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
   * @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, struct efi_event **event)
  {
  	int i;
  
  	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;
  
  	for (i = 0; i < ARRAY_SIZE(efi_events); ++i) {
  		if (efi_events[i].type)
  			continue;
  		efi_events[i].type = type;
  		efi_events[i].notify_tpl = notify_tpl;
  		efi_events[i].notify_function = notify_function;
  		efi_events[i].notify_context = notify_context;
  		/* Disable timers on bootup */
  		efi_events[i].trigger_next = -1ULL;
  		efi_events[i].is_queued = false;
  		efi_events[i].is_signaled = false;
  		*event = &efi_events[i];
  		return EFI_SUCCESS;
  	}
  	return EFI_OUT_OF_RESOURCES;
  }
  
  /*
   * Create an event in a group.
   *
   * This function implements the CreateEventEx service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   * TODO: Support event groups
   *
   * @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
   * @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);
  	if (event_group)
  		return EFI_EXIT(EFI_UNSUPPORTED);
  	return EFI_EXIT(efi_create_event(type, notify_tpl, notify_function,
  					 notify_context, event));
  }
  
  /*
   * Create an event.
   *
   * This function implements the CreateEvent service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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, event));
  }
  
  
  /*
   * 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)
  {
  	int i;
  	u64 now = timer_get_us();
  
  	for (i = 0; i < ARRAY_SIZE(efi_events); ++i) {
  		if (!efi_events[i].type)
  			continue;
  		if (efi_events[i].is_queued)
  			efi_signal_event(&efi_events[i], true);
  		if (!(efi_events[i].type & EVT_TIMER) ||
  		    now < efi_events[i].trigger_next)
  			continue;
  		switch (efi_events[i].trigger_type) {
  		case EFI_TIMER_RELATIVE:
  			efi_events[i].trigger_type = EFI_TIMER_STOP;
  			break;
  		case EFI_TIMER_PERIODIC:
  			efi_events[i].trigger_next +=
  				efi_events[i].trigger_time;
  			break;
  		default:
  			continue;
  		}
  		efi_events[i].is_signaled = true;
  		efi_signal_event(&efi_events[i], true);
  	}
  	WATCHDOG_RESET();
  }
  
  /*
   * Set the trigger time for a timer event or stop the event.
   *
   * This is the function for internal usage in U-Boot. For the API function
   * implementing the SetTimer service see efi_set_timer_ext.
   *
   * @event		event for which the timer is set
   * @type		type of the timer
   * @trigger_time	trigger period in multiples of 100ns
   * @return		status code
   */
  efi_status_t efi_set_timer(struct efi_event *event, enum efi_timer_delay type,
  			   uint64_t trigger_time)
  {
  	int i;
  
  	/*
  	 * The parameter defines a multiple of 100ns.
  	 * We use multiples of 1000ns. So divide by 10.
  	 */
  	do_div(trigger_time, 10);
  
  	for (i = 0; i < ARRAY_SIZE(efi_events); ++i) {
  		if (event != &efi_events[i])
  			continue;
  
  		if (!(event->type & EVT_TIMER))
  			break;
  		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;
  	}
  	return EFI_INVALID_PARAMETER;
  }
  
  /*
   * Set the trigger time for a timer event or stop the event.
   *
   * This function implements the SetTimer service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @event		event for which the timer is set
   * @type		type of the timer
   * @trigger_time	trigger period in multiples of 100ns
   * @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));
  }
  
  /*
   * Wait for events to be signaled.
   *
   * This function implements the WaitForEvent service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @num_events	number of events to be waited for
   * @events	events to be waited for
   * @index	index of the event that was signaled
   * @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, j;
  
  	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) {
  		for (j = 0; j < ARRAY_SIZE(efi_events); ++j) {
  			if (event[i] == &efi_events[j])
  				goto known_event;
  		}
  		return EFI_EXIT(EFI_INVALID_PARAMETER);
  known_event:
  		if (!event[i]->type || event[i]->type & EVT_NOTIFY_SIGNAL)
  			return EFI_EXIT(EFI_INVALID_PARAMETER);
  		if (!event[i]->is_signaled)
  			efi_signal_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);
  }
  
  /*
   * Signal an EFI event.
   *
   * 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.
   *
   * @event	event to signal
   * @return	status code
   */
  static efi_status_t EFIAPI efi_signal_event_ext(struct efi_event *event)
  {
  	int i;
  
  	EFI_ENTRY("%p", event);
  	for (i = 0; i < ARRAY_SIZE(efi_events); ++i) {
  		if (event != &efi_events[i])
  			continue;
  		if (event->is_signaled)
  			break;
  		event->is_signaled = true;
  		if (event->type & EVT_NOTIFY_SIGNAL)
  			efi_signal_event(event, true);
  		break;
  	}
  	return EFI_EXIT(EFI_SUCCESS);
  }
  
  /*
   * Close an EFI event.
   *
   * This function implements the CloseEvent service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @event	event to close
   * @return	status code
   */
  static efi_status_t EFIAPI efi_close_event(struct efi_event *event)
  {
  	int i;
  
  	EFI_ENTRY("%p", event);
  	for (i = 0; i < ARRAY_SIZE(efi_events); ++i) {
  		if (event == &efi_events[i]) {
  			event->type = 0;
  			event->trigger_next = -1ULL;
  			event->is_queued = false;
  			event->is_signaled = false;
  			return EFI_EXIT(EFI_SUCCESS);
  		}
  	}
  	return EFI_EXIT(EFI_INVALID_PARAMETER);
  }
  
  /*
   * Check if an event is signaled.
   *
   * 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.
   *
   * @event	event to check
   * @return	status code
   */
  static efi_status_t EFIAPI efi_check_event(struct efi_event *event)
  {
  	int i;
  
  	EFI_ENTRY("%p", event);
  	efi_timer_check();
  	for (i = 0; i < ARRAY_SIZE(efi_events); ++i) {
  		if (event != &efi_events[i])
  			continue;
  		if (!event->type || event->type & EVT_NOTIFY_SIGNAL)
  			break;
  		if (!event->is_signaled)
  			efi_signal_event(event, true);
  		if (event->is_signaled)
  			return EFI_EXIT(EFI_SUCCESS);
  		return EFI_EXIT(EFI_NOT_READY);
  	}
  	return EFI_EXIT(EFI_INVALID_PARAMETER);
  }
  
  /*
   * 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;
  }
  
  /*
   * 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;
  }
  
  /*
   * Remove an open protocol info entry from a protocol.
   *
   * @handler	handler of a protocol
   * @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;
  }
  
  /*
   * 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'
  ", protocol_interface);
  	return EFI_SUCCESS;
  }
  
  /*
   * Install protocol interface.
   *
   * This function implements the InstallProtocolInterface service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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
  ", indent_string(nesting_level),
  		      *handle);
  	} else {
  		debug("%sEFI: handle %p
  ", indent_string(nesting_level),
  		      *handle);
  	}
  	/* Add new protocol */
  	r = efi_add_protocol(*handle, protocol, protocol_interface);
  out:
  	return EFI_EXIT(r);
  }
  
  /*
   * Reinstall protocol interface.
   *
   * This function implements the ReinstallProtocolInterface service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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_ENTRY("%p, %pUl, %p, %p", handle, protocol, old_interface,
  		  new_interface);
  	return EFI_EXIT(EFI_ACCESS_DENIED);
  }
  
  /*
   * Get all drivers associated to a controller.
   * The allocated buffer has to be freed with free().
   *
   * @efiobj			handle of the controller
   * @protocol			protocol guid (optional)
   * @number_of_drivers		number of child controllers
   * @driver_handle_buffer	handles of the the drivers
   * @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;
  }
  
  /*
   * Disconnect all drivers from a controller.
   *
   * This function implements the DisconnectController service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @efiobj		handle of the controller
   * @protocol		protocol guid (optional)
   * @child_handle	handle of the child to destroy
   * @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;
  }
  
  /*
   * Uninstall protocol interface.
   *
   * This function implements the UninstallProtocolInterface service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @handle			handle from which the protocol shall be removed
   * @protocol			GUID of the protocol to be removed
   * @protocol_interface		interface to be removed
   * @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);
  }
  
  /*
   * Register an event for notification when a protocol is installed.
   *
   * This function implements the RegisterProtocolNotify service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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);
  }
  
  /*
   * Determine if an EFI handle implements a protocol.
   *
   * See the documentation of the LocateHandle service in the UEFI specification.
   *
   * @search_type		selection criterion
   * @protocol		GUID of the protocol
   * @search_key		registration key
   * @efiobj		handle
   * @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;
  	}
  }
  
  /*
   * Locate handles implementing a protocol.
   *
   * This function is meant for U-Boot internal calls. For the API implementation
   * of the LocateHandle service see efi_locate_handle_ext.
   *
   * @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
   * @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;
  }
  
  /*
   * Locate handles implementing a protocol.
   *
   * This function implements the LocateHandle service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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));
  }
  
  /* Collapses configuration table entries, removing index i */
  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--;
  }
  
  /*
   * Adds, updates, or removes a configuration table.
   *
   * This function is used for internal calls. For the API implementation of the
   * InstallConfigurationTable service see efi_install_configuration_table_ext.
   *
   * @guid		GUID of the installed table
   * @table		table to be installed
   * @return		status code
   */
  efi_status_t efi_install_configuration_table(const efi_guid_t *guid, void *table)
  {
  	int i;
  
  	/* 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);
  			return EFI_SUCCESS;
  		}
  	}
  
  	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;
  
  	return EFI_SUCCESS;
  }
  
  /*
   * Adds, updates, or removes a configuration table.
   *
   * This function implements the InstallConfigurationTable service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @guid		GUID of the installed table
   * @table		table to be installed
   * @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));
  }
  
  /*
   * Initialize a loaded_image_info + loaded_image_info object with correct
   * protocols, boot-device, etc.
   *
   * @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
   * @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_console_control,
  			       (void *)&efi_console_control);
  	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;
  
  	return ret;
  failure:
  	printf("ERROR: Failure to install protocols for loaded image
  ");
  	return ret;
  }
  
  /*
   * 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;
  	uint64_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;
  
  	EFI_CALL(ret = f->read(f, &info->file_size, *buffer));
  
  error:
  	free(info);
  	EFI_CALL(f->close(f));
  
  	if (ret != EFI_SUCCESS) {
  		efi_free_pool(*buffer);
  		*buffer = NULL;
  	}
  
  	return ret;
  }
  
  /*
   * Load an EFI image into memory.
   *
   * This function implements the LoadImage service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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,
  					  unsigned long 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, %ld, %p", boot_policy, parent_image,
  		  file_path, source_buffer, source_size, image_handle);
  
  	info = calloc(1, sizeof(*info));
  	obj = calloc(1, sizeof(*obj));
  
  	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);
  	return EFI_EXIT(ret);
  }
  
  /*
   * Call the entry point of an image.
   *
   * This function implements the StartImage service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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
  ",
  		      __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));
  }
  
  /*
   * Leave an EFI application or driver.
   *
   * This function implements the Exit service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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");
  }
  
  /*
   * Unload an EFI image.
   *
   * This function implements the UnloadImage service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @image_handle	handle of the image to be unloaded
   * @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);
  }
  
  /*
   * 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
  }
  
  /*
   * Stop all boot services.
   *
   * 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.
   *
   * @image_handle	handle of the loaded image
   * @map_key		key of the memory map
   * @return		status code
   */
  static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
  						  unsigned long map_key)
  {
  	int i;
  
  	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);
  
  	/* Notify that ExitBootServices is invoked. */
  	for (i = 0; i < ARRAY_SIZE(efi_events); ++i) {
  		if (efi_events[i].type != EVT_SIGNAL_EXIT_BOOT_SERVICES)
  			continue;
  		efi_events[i].is_signaled = true;
  		efi_signal_event(&efi_events[i], false);
  	}
  
  	/* 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);
  }
  
  /*
   * Get next value of the counter.
   *
   * This function implements the NextMonotonicCount service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @count	returned value of the counter
   * @return	status code
   */
  static efi_status_t EFIAPI efi_get_next_monotonic_count(uint64_t *count)
  {
  	static uint64_t mono = 0;
  	EFI_ENTRY("%p", count);
  	*count = mono++;
  	return EFI_EXIT(EFI_SUCCESS);
  }
  
  /*
   * Sleep.
   *
   * This function implements the Stall sercive.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @microseconds	period to sleep in microseconds
   * @return		status code
   */
  static efi_status_t EFIAPI efi_stall(unsigned long microseconds)
  {
  	EFI_ENTRY("%ld", microseconds);
  	udelay(microseconds);
  	return EFI_EXIT(EFI_SUCCESS);
  }
  
  /*
   * Reset the watchdog timer.
   *
   * This function implements the SetWatchdogTimer service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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));
  }
  
  /*
   * Close a protocol.
   *
   * This function implements the CloseProtocol service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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);
  }
  
  /*
   * Provide information about then open status of a protocol on a handle
   *
   * This function implements the OpenProtocolInformation service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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);
  }
  
  /*
   * Get protocols installed on a handle.
   *
   * This function implements the ProtocolsPerHandleService.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @handle			handle for which the information is retrieved
   * @protocol_buffer		buffer with protocol GUIDs
   * @protocol_buffer_count	number of entries in the buffer
   * @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);
  }
  
  /*
   * Locate handles implementing a protocol.
   *
   * This function implements the LocateHandleBuffer service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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);
  }
  
  /*
   * Find an interface implementing a protocol.
   *
   * This function implements the LocateProtocol service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @protocol		GUID of the protocol
   * @registration	registration key passed to the notification function
   * @protocol_interface	interface implementing the protocol
   * @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);
  }
  
  /*
   * Get the device path and handle of an device implementing a protocol.
   *
   * This function implements the LocateDevicePath service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @protocol		GUID of the protocol
   * @device_path		device path
   * @device		handle of the device
   * @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_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_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);
  }
  
  /*
   * Install multiple protocol interfaces.
   *
   * This function implements the MultipleProtocolInterfaces service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @handle	handle on which the protocol interfaces shall be installed
   * @...		NULL terminated argument list with pairs of protocol GUIDS and
   *		interfaces
   * @return	status code
   */
  static efi_status_t EFIAPI efi_install_multiple_protocol_interfaces(
  			void **handle, ...)
  {
  	EFI_ENTRY("%p", handle);
  
  	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);
  
  	va_start(argptr, handle);
  	for (;;) {
  		protocol = va_arg(argptr, efi_guid_t*);
  		if (!protocol)
  			break;
  		protocol_interface = va_arg(argptr, void*);
  		r = EFI_CALL(efi_install_protocol_interface(
  						handle, protocol,
  						EFI_NATIVE_INTERFACE,
  						protocol_interface));
  		if (r != EFI_SUCCESS)
  			break;
  		i++;
  	}
  	va_end(argptr);
  	if (r == EFI_SUCCESS)
  		return EFI_EXIT(r);
  
  	/* If an error occurred undo all changes. */
  	va_start(argptr, handle);
  	for (; i; --i) {
  		protocol = va_arg(argptr, efi_guid_t*);
  		protocol_interface = va_arg(argptr, void*);
  		EFI_CALL(efi_uninstall_protocol_interface(handle, protocol,
  							  protocol_interface));
  	}
  	va_end(argptr);
  
  	return EFI_EXIT(r);
  }
  
  /*
   * Uninstall multiple protocol interfaces.
   *
   * This function implements the UninstallMultipleProtocolInterfaces service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @handle	handle from which the protocol interfaces shall be removed
   * @...		NULL terminated argument list with pairs of protocol GUIDS and
   *		interfaces
   * @return	status code
   */
  static efi_status_t EFIAPI efi_uninstall_multiple_protocol_interfaces(
  			void *handle, ...)
  {
  	EFI_ENTRY("%p", handle);
  
  	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);
  
  	va_start(argptr, handle);
  	for (;;) {
  		protocol = va_arg(argptr, efi_guid_t*);
  		if (!protocol)
  			break;
  		protocol_interface = va_arg(argptr, void*);
  		r = EFI_CALL(efi_uninstall_protocol_interface(
  						handle, protocol,
  						protocol_interface));
  		if (r != EFI_SUCCESS)
  			break;
  		i++;
  	}
  	va_end(argptr);
  	if (r == EFI_SUCCESS)
  		return EFI_EXIT(r);
  
  	/* If an error occurred undo all changes. */
  	va_start(argptr, handle);
  	for (; i; --i) {
  		protocol = va_arg(argptr, efi_guid_t*);
  		protocol_interface = va_arg(argptr, void*);
  		EFI_CALL(efi_install_protocol_interface(&handle, protocol,
  							EFI_NATIVE_INTERFACE,
  							protocol_interface));
  	}
  	va_end(argptr);
  
  	return EFI_EXIT(r);
  }
  
  /*
   * Calculate cyclic redundancy code.
   *
   * This function implements the CalculateCrc32 service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @data	buffer with data
   * @data_size	size of buffer in bytes
   * @crc32_p	cyclic redundancy code
   * @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);
  }
  
  /*
   * Copy memory.
   *
   * This function implements the CopyMem service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @destination		destination of the copy operation
   * @source		source of the copy operation
   * @length		number of bytes to copy
   */
  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);
  }
  
  /*
   * Fill memory with a byte value.
   *
   * This function implements the SetMem service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @buffer		buffer to fill
   * @size		size of buffer in bytes
   * @value		byte to copy to the buffer
   */
  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);
  }
  
  /*
   * 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;
  }
  
  /*
   * Open protocol interface on a handle.
   *
   * This function implements the OpenProtocol interface.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @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
   * @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);
  }
  
  /*
   * Get interface of a protocol on a handle.
   *
   * This function implements the HandleProtocol service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @handle		handle on which the protocol shall be opened
   * @protocol		GUID of the protocol
   * @protocol_interface  interface implementing the protocol
   * @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);
  }
  
  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;
  }
  
  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;
  }
  
  /*
   * Connect a controller to a driver.
   *
   * 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.
   *
   * @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
   * @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);
  }
  
  /*
   * Get all child controllers associated to a driver.
   * The allocated buffer has to be freed with free().
   *
   * @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
   */
  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;
  }
  
  /*
   * Disconnect a controller from a driver.
   *
   * This function implements the DisconnectController service.
   * See the Unified Extensible Firmware Interface (UEFI) specification
   * for details.
   *
   * @controller_handle	handle of the controller
   * @driver_image_handle handle of the driver
   * @child_handle	handle of the child to destroy
   * @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,
  };