xref: /OK3568_Linux_fs/u-boot/arch/arm/cpu/arm946es/start.S (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun/*
2*4882a593Smuzhiyun *  armboot - Startup Code for ARM926EJS CPU-core
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun *  Copyright (c) 2003  Texas Instruments
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun *  ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun *  Copyright (c) 2001	Marius Gröger <mag@sysgo.de>
9*4882a593Smuzhiyun *  Copyright (c) 2002	Alex Züpke <azu@sysgo.de>
10*4882a593Smuzhiyun *  Copyright (c) 2002	Gary Jennejohn <garyj@denx.de>
11*4882a593Smuzhiyun *  Copyright (c) 2003	Richard Woodruff <r-woodruff2@ti.com>
12*4882a593Smuzhiyun *  Copyright (c) 2003	Kshitij <kshitij@ti.com>
13*4882a593Smuzhiyun *  Copyright (c) 2010	Albert Aribaud <albert.u.boot@aribaud.net>
14*4882a593Smuzhiyun *
15*4882a593Smuzhiyun * SPDX-License-Identifier:	GPL-2.0+
16*4882a593Smuzhiyun */
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun#include <asm-offsets.h>
19*4882a593Smuzhiyun#include <config.h>
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun/*
22*4882a593Smuzhiyun *************************************************************************
23*4882a593Smuzhiyun *
24*4882a593Smuzhiyun * Startup Code (reset vector)
25*4882a593Smuzhiyun *
26*4882a593Smuzhiyun * do important init only if we don't start from memory!
27*4882a593Smuzhiyun * setup Memory and board specific bits prior to relocation.
28*4882a593Smuzhiyun * relocate armboot to ram
29*4882a593Smuzhiyun * setup stack
30*4882a593Smuzhiyun *
31*4882a593Smuzhiyun *************************************************************************
32*4882a593Smuzhiyun */
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun	.globl	reset
35*4882a593Smuzhiyun
36*4882a593Smuzhiyunreset:
37*4882a593Smuzhiyun	/*
38*4882a593Smuzhiyun	 * set the cpu to SVC32 mode
39*4882a593Smuzhiyun	 */
40*4882a593Smuzhiyun	mrs	r0,cpsr
41*4882a593Smuzhiyun	bic	r0,r0,#0x1f
42*4882a593Smuzhiyun	orr	r0,r0,#0xd3
43*4882a593Smuzhiyun	msr	cpsr,r0
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun	/*
46*4882a593Smuzhiyun	 * we do sys-critical inits only at reboot,
47*4882a593Smuzhiyun	 * not when booting from ram!
48*4882a593Smuzhiyun	 */
49*4882a593Smuzhiyun#ifndef CONFIG_SKIP_LOWLEVEL_INIT
50*4882a593Smuzhiyun	bl	cpu_init_crit
51*4882a593Smuzhiyun#endif
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun	bl	_main
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun/*------------------------------------------------------------------------------*/
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun	.globl	c_runtime_cpu_setup
58*4882a593Smuzhiyunc_runtime_cpu_setup:
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun	mov	pc, lr
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun/*
63*4882a593Smuzhiyun *************************************************************************
64*4882a593Smuzhiyun *
65*4882a593Smuzhiyun * CPU_init_critical registers
66*4882a593Smuzhiyun *
67*4882a593Smuzhiyun * setup important registers
68*4882a593Smuzhiyun * setup memory timing
69*4882a593Smuzhiyun *
70*4882a593Smuzhiyun *************************************************************************
71*4882a593Smuzhiyun */
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun#ifndef CONFIG_SKIP_LOWLEVEL_INIT
75*4882a593Smuzhiyuncpu_init_crit:
76*4882a593Smuzhiyun	/*
77*4882a593Smuzhiyun	 * flush v4 I/D caches
78*4882a593Smuzhiyun	 */
79*4882a593Smuzhiyun	mov	r0, #0
80*4882a593Smuzhiyun	mcr	p15, 0, r0, c7, c5, 0	/* flush v4 I-cache */
81*4882a593Smuzhiyun	mcr	p15, 0, r0, c7, c6, 0	/* flush v4 D-cache */
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun	/*
84*4882a593Smuzhiyun	 * disable MMU stuff and caches
85*4882a593Smuzhiyun	 */
86*4882a593Smuzhiyun	mrc	p15, 0, r0, c1, c0, 0
87*4882a593Smuzhiyun	bic	r0, r0, #0x00002300	/* clear bits 13, 9:8 (--V- --RS) */
88*4882a593Smuzhiyun	bic	r0, r0, #0x00000087	/* clear bits 7, 2:0 (B--- -CAM) */
89*4882a593Smuzhiyun	orr	r0, r0, #0x00000002	/* set bit 1 (A) Align */
90*4882a593Smuzhiyun	orr	r0, r0, #0x00001000	/* set bit 12 (I) I-Cache */
91*4882a593Smuzhiyun	mcr	p15, 0, r0, c1, c0, 0
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY
94*4882a593Smuzhiyun	/*
95*4882a593Smuzhiyun	 * Go setup Memory and board specific bits prior to relocation.
96*4882a593Smuzhiyun	 */
97*4882a593Smuzhiyun	mov	ip, lr		/* perserve link reg across call */
98*4882a593Smuzhiyun	bl	lowlevel_init	/* go setup memory */
99*4882a593Smuzhiyun	mov	lr, ip		/* restore link */
100*4882a593Smuzhiyun#endif
101*4882a593Smuzhiyun	mov	pc, lr		/* back to my caller */
102*4882a593Smuzhiyun#endif
103