xref: /openbmc/u-boot/arch/arm/cpu/arm926ejs/spear/start.S (revision da4105df)
1/*
2 *  armboot - Startup Code for ARM926EJS CPU-core
3 *
4 *  Copyright (c) 2003  Texas Instruments
5 *
6 *  ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------
7 *
8 *  Copyright (c) 2001	Marius Gröger <mag@sysgo.de>
9 *  Copyright (c) 2002	Alex Züpke <azu@sysgo.de>
10 *  Copyright (c) 2002	Gary Jennejohn <garyj@denx.de>
11 *  Copyright (c) 2003	Richard Woodruff <r-woodruff2@ti.com>
12 *  Copyright (c) 2003	Kshitij <kshitij@ti.com>
13 *
14 * SPDX-License-Identifier:	GPL-2.0+
15 */
16
17
18#include <config.h>
19
20.globl _start
21_start:
22	b	reset
23	ldr	pc, _undefined_instruction
24	ldr	pc, _software_interrupt
25	ldr	pc, _prefetch_abort
26	ldr	pc, _data_abort
27	ldr	pc, _not_used
28	ldr	pc, _irq
29	ldr	pc, _fiq
30
31_undefined_instruction:
32_software_interrupt:
33_prefetch_abort:
34_data_abort:
35_not_used:
36_irq:
37_fiq:
38	.word infinite_loop
39
40infinite_loop:
41	b	infinite_loop
42
43/*
44 *************************************************************************
45 *
46 * Startup Code (reset vector)
47 *
48 * Below are the critical initializations already taken place in BootROM.
49 * So, these are not taken care in Xloader
50 * 1. Relocation to RAM
51 * 2. Initializing stacks
52 *
53 *************************************************************************
54 */
55
56/*
57 * the actual reset code
58 */
59
60reset:
61/*
62 * Xloader has to return back to BootROM in a few cases.
63 * eg. Ethernet boot, UART boot, USB boot
64 * Saving registers for returning back
65 */
66	stmdb	sp!, {r0-r12,r14}
67	bl	cpu_init_crit
68/*
69 * Clearing bss area is not done in Xloader.
70 * BSS area lies in the DDR location which is not yet initialized
71 * bss is assumed to be uninitialized.
72 */
73	bl	spl_boot
74	ldmia	sp!, {r0-r12,pc}
75
76/*
77 *************************************************************************
78 *
79 * CPU_init_critical registers
80 *
81 * setup important registers
82 * setup memory timing
83 *
84 *************************************************************************
85 */
86cpu_init_crit:
87	/*
88	 * flush v4 I/D caches
89	 */
90	mov	r0, #0
91	mcr	p15, 0, r0, c7, c7, 0	/* flush v3/v4 cache */
92	mcr	p15, 0, r0, c8, c7, 0	/* flush v4 TLB */
93
94	/*
95	 * enable instruction cache
96	 */
97	mrc	p15, 0, r0, c1, c0, 0
98	orr	r0, r0, #0x00001000	/* set bit 12 (I) I-Cache */
99	mcr	p15, 0, r0, c1, c0, 0
100
101	/*
102	 * Go setup Memory and board specific bits prior to relocation.
103	 */
104	stmdb	sp!, {lr}
105	bl	lowlevel_init	/* go setup pll,mux,memory */
106	ldmia	sp!, {pc}
107