xref: /OK3568_Linux_fs/u-boot/arch/arm/cpu/arm720t/start.S (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun/*
2*4882a593Smuzhiyun *  armboot - Startup Code for ARM720 CPU-core
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun *  Copyright (c) 2001	Marius Gröger <mag@sysgo.de>
5*4882a593Smuzhiyun *  Copyright (c) 2002	Alex Züpke <azu@sysgo.de>
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * SPDX-License-Identifier:	GPL-2.0+
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun#include <asm-offsets.h>
11*4882a593Smuzhiyun#include <config.h>
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun/*
14*4882a593Smuzhiyun *************************************************************************
15*4882a593Smuzhiyun *
16*4882a593Smuzhiyun * Startup Code (reset vector)
17*4882a593Smuzhiyun *
18*4882a593Smuzhiyun * do important init only if we don't start from RAM!
19*4882a593Smuzhiyun * relocate armboot to ram
20*4882a593Smuzhiyun * setup stack
21*4882a593Smuzhiyun * jump to second stage
22*4882a593Smuzhiyun *
23*4882a593Smuzhiyun *************************************************************************
24*4882a593Smuzhiyun */
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun	.globl	reset
27*4882a593Smuzhiyun
28*4882a593Smuzhiyunreset:
29*4882a593Smuzhiyun	/*
30*4882a593Smuzhiyun	 * set the cpu to SVC32 mode
31*4882a593Smuzhiyun	 */
32*4882a593Smuzhiyun	mrs	r0,cpsr
33*4882a593Smuzhiyun	bic	r0,r0,#0x1f
34*4882a593Smuzhiyun	orr	r0,r0,#0xd3
35*4882a593Smuzhiyun	msr	cpsr,r0
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun	/*
38*4882a593Smuzhiyun	 * we do sys-critical inits only at reboot,
39*4882a593Smuzhiyun	 * not when booting from ram!
40*4882a593Smuzhiyun	 */
41*4882a593Smuzhiyun#if !defined(CONFIG_SKIP_LOWLEVEL_INIT) && \
42*4882a593Smuzhiyun		!defined(CONFIG_SKIP_LOWLEVEL_INIT_ONLY)
43*4882a593Smuzhiyun	bl	cpu_init_crit
44*4882a593Smuzhiyun#endif
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun	bl	_main
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun/*------------------------------------------------------------------------------*/
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun	.globl	c_runtime_cpu_setup
51*4882a593Smuzhiyunc_runtime_cpu_setup:
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun	mov	pc, lr
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun/*
56*4882a593Smuzhiyun *************************************************************************
57*4882a593Smuzhiyun *
58*4882a593Smuzhiyun * CPU_init_critical registers
59*4882a593Smuzhiyun *
60*4882a593Smuzhiyun * setup important registers
61*4882a593Smuzhiyun * setup memory timing
62*4882a593Smuzhiyun *
63*4882a593Smuzhiyun *************************************************************************
64*4882a593Smuzhiyun */
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun#if !defined(CONFIG_SKIP_LOWLEVEL_INIT) && \
67*4882a593Smuzhiyun		!defined(CONFIG_SKIP_LOWLEVEL_INIT_ONLY)
68*4882a593Smuzhiyuncpu_init_crit:
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun	mov	ip, lr
71*4882a593Smuzhiyun	/*
72*4882a593Smuzhiyun	 * before relocating, we have to setup RAM timing
73*4882a593Smuzhiyun	 * because memory timing is board-dependent, you will
74*4882a593Smuzhiyun	 * find a lowlevel_init.S in your board directory.
75*4882a593Smuzhiyun	 */
76*4882a593Smuzhiyun	bl	lowlevel_init
77*4882a593Smuzhiyun	mov	lr, ip
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun	mov	pc, lr
80*4882a593Smuzhiyun#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
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