1 /*
2 * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <gpxe/nap.h>
22 #include <gpxe/efi/efi.h>
23
24 /** @file
25 *
26 * gPXE CPU sleeping API for EFI
27 *
28 */
29
30 /**
31 * Sleep until next interrupt
32 *
33 */
efix86_cpu_nap(void)34 static void efix86_cpu_nap ( void ) {
35 /*
36 * I can't find any EFI API that allows us to put the CPU to
37 * sleep. The CpuSleep() function is defined in CpuLib.h, but
38 * isn't part of any exposed protocol so we have no way to
39 * call it.
40 *
41 * The EFI shell doesn't seem to bother sleeping the CPU; it
42 * just sits there idly burning power.
43 *
44 */
45 __asm__ __volatile__ ( "hlt" );
46 }
47
48 PROVIDE_NAP ( efix86, cpu_nap, efix86_cpu_nap );
49