xref: /openbmc/u-boot/arch/arm/lib/cmd_boot.c (revision f99993c1)
1*f99993c1SMatt Porter /*
2*f99993c1SMatt Porter  * (C) Copyright 2008-2011
3*f99993c1SMatt Porter  * Graeme Russ, <graeme.russ@gmail.com>
4*f99993c1SMatt Porter  *
5*f99993c1SMatt Porter  * (C) Copyright 2002
6*f99993c1SMatt Porter  * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
7*f99993c1SMatt Porter  *
8*f99993c1SMatt Porter  * (C) Copyright 2002
9*f99993c1SMatt Porter  * Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
10*f99993c1SMatt Porter  *
11*f99993c1SMatt Porter  * (C) Copyright 2002
12*f99993c1SMatt Porter  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
13*f99993c1SMatt Porter  * Marius Groeger <mgroeger@sysgo.de>
14*f99993c1SMatt Porter  *
15*f99993c1SMatt Porter  * Copyright 2015 ATS Advanced Telematics Systems GmbH
16*f99993c1SMatt Porter  * Copyright 2015 Konsulko Group, Matt Porter <mporter@konsulko.com>
17*f99993c1SMatt Porter  *
18*f99993c1SMatt Porter  * SPDX-License-Identifier:	GPL-2.0+
19*f99993c1SMatt Porter  */
20*f99993c1SMatt Porter 
21*f99993c1SMatt Porter #include <common.h>
22*f99993c1SMatt Porter #include <command.h>
23*f99993c1SMatt Porter 
24*f99993c1SMatt Porter DECLARE_GLOBAL_DATA_PTR;
25*f99993c1SMatt Porter 
26*f99993c1SMatt Porter /*
27*f99993c1SMatt Porter  * ARMv7M does not support ARM instruction mode. However, the
28*f99993c1SMatt Porter  * interworking BLX and BX instructions do encode the ARM/Thumb
29*f99993c1SMatt Porter  * field in bit 0. This means that when executing any Branch
30*f99993c1SMatt Porter  * and eXchange instruction we must set bit 0 to one to guarantee
31*f99993c1SMatt Porter  * that we keep the processor in Thumb instruction mode. From The
32*f99993c1SMatt Porter  * ARMv7-M Instruction Set A4.1.1:
33*f99993c1SMatt Porter  *   "ARMv7-M only supports the Thumb instruction execution state,
34*f99993c1SMatt Porter  *    therefore the value of address bit [0] must be 1 in interworking
35*f99993c1SMatt Porter  *    instructions, otherwise a fault occurs."
36*f99993c1SMatt Porter  */
37*f99993c1SMatt Porter unsigned long do_go_exec(ulong (*entry)(int, char * const []),
38*f99993c1SMatt Porter 			 int argc, char * const argv[])
39*f99993c1SMatt Porter {
40*f99993c1SMatt Porter 	ulong addr = (ulong)entry | 1;
41*f99993c1SMatt Porter 	entry = (void *)addr;
42*f99993c1SMatt Porter 
43*f99993c1SMatt Porter 	return entry(argc, argv);
44*f99993c1SMatt Porter }
45