[efi] Do not raise TPL within EFI_DRIVER_BINDING_PROTOCOL.Supported()
[ipxe.git] / src / arch / arm / interface / efi / efiarm_nap.c
1 /*
2 * Copyright (C) 2016 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., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 #include <ipxe/nap.h>
27 #include <ipxe/efi/efi.h>
28
29 /** @file
30 *
31 * iPXE CPU sleeping API for EFI
32 *
33 */
34
35 /**
36 * Sleep until next interrupt
37 *
38 */
39 static void efiarm_cpu_nap ( void ) {
40 /*
41 * I can't find any EFI API that allows us to put the CPU to
42 * sleep. The CpuSleep() function is defined in CpuLib.h, but
43 * isn't part of any exposed protocol so we have no way to
44 * call it.
45 *
46 * The EFI shell doesn't seem to bother sleeping the CPU; it
47 * just sits there idly burning power.
48 *
49 */
50 __asm__ __volatile__ ( "wfi" );
51 }
52
53 PROVIDE_NAP ( efiarm, cpu_nap, efiarm_cpu_nap );