| /* |
| * 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 ); |