1/*-
2 * Copyright (c) 2008 Semihalf, Rafal Czubak
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29#include <machine/asm.h>
30#include <machine/armreg.h>
31
32/*
33 * Entry point to the loader that U-Boot passes control to.
34 */
35	.text
36	.globl	_start
37_start:
38	/* Hint where to look for the API signature */
39	ldr	ip, =uboot_address
40	str	sp, [ip]
41
42	/* Save U-Boot's r8 and r9 */
43	ldr	ip, =saved_regs
44	str	r8, [ip, #0]
45	str	r9, [ip, #4]
46
47#ifdef _ARM_ARCH_6
48	mrc     p15, 0, r2, c1, c0, 0
49	orr	r2, r2, #(CPU_CONTROL_UNAL_ENABLE)
50	orr	r2, r2, #(CPU_CONTROL_AFLT_ENABLE)
51	mcr     p15, 0, r2, c1, c0, 0
52#endif
53
54	/* Start loader */
55	b	main
56
57/*
58 * syscall()
59 */
60ENTRY(syscall)
61	/* Save caller's lr, r8 and r9 */
62	ldr	ip, =saved_regs
63	str	r8, [ip, #8]
64	str	r9, [ip, #12]
65	str	lr, [ip, #16]
66	/* Restore U-Boot's r8 and r9 */
67	ldr	r8, [ip, #0]
68	ldr	r9, [ip, #4]
69	/* Call into U-Boot */
70	ldr	lr, =return_from_syscall
71	ldr	ip, =syscall_ptr
72	ldr	pc, [ip]
73return_from_syscall:
74	/* Restore loader's r8, r9 and lr */
75	ldr	ip, =saved_regs
76	ldr	lr, [ip, #16]
77	ldr	r9, [ip, #12]
78	ldr	r8, [ip, #8]
79	/* Return to caller */
80	mov	pc, lr
81
82/*
83 * Data section
84 */
85	.data
86	.align	4
87	.globl	syscall_ptr
88syscall_ptr:
89	.long	0
90
91	.globl	uboot_address
92uboot_address:
93	.long	0
94
95saved_regs:
96	.long	0	/* U-Boot's r8 */
97	.long	0	/* U-Boot's r9 */
98	.long	0	/* Loader's r8 */
99	.long	0	/* Loader's r9 */
100	.long	0	/* Loader's lr */
101