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/*
* Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <ipxe/nap.h>
#include <ipxe/efi/efi.h>
/** @file
*
* iPXE CPU sleeping API for EFI
*
*/
/**
* Sleep until next interrupt
*
*/
static void efiarm_cpu_nap ( void ) {
/*
* I can't find any EFI API that allows us to put the CPU to
* sleep. The CpuSleep() function is defined in CpuLib.h, but
* isn't part of any exposed protocol so we have no way to
* call it.
*
* The EFI shell doesn't seem to bother sleeping the CPU; it
* just sits there idly burning power.
*
* If a shutdown is in progess, there may be nothing to
* generate an interrupt since the timer is disabled in the
* first step of ExitBootServices().
*/
if ( ! efi_shutdown_in_progress )
__asm__ __volatile__ ( "wfi" );
}
PROVIDE_NAP ( efiarm, cpu_nap, efiarm_cpu_nap );
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