1/*
2 *  linux/arch/arm/kernel/head-nommu.S
3 *
4 *  Copyright (C) 1994-2002 Russell King
5 *  Copyright (C) 2003-2006 Hyok S. Choi
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 *  Common kernel startup code (non-paged MM)
12 *
13 */
14#include <linux/linkage.h>
15#include <linux/init.h>
16
17#include <asm/assembler.h>
18#include <asm/mach-types.h>
19#include <asm/ptrace.h>
20#include <asm/asm-offsets.h>
21#include <asm/thread_info.h>
22#include <asm/system.h>
23
24/*
25 * Kernel startup entry point.
26 * ---------------------------
27 *
28 * This is normally called from the decompressor code.  The requirements
29 * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
30 * r1 = machine nr.
31 *
32 * See linux/arch/arm/tools/mach-types for the complete list of machine
33 * numbers for r1.
34 *
35 */
36	.section ".text.head", "ax"
37	.type	stext, %function
38ENTRY(stext)
39	msr	cpsr_c, #PSR_F_BIT | PSR_I_BIT | SVC_MODE @ ensure svc mode
40						@ and irqs disabled
41#ifndef CONFIG_CPU_CP15
42	ldr	r9, =CONFIG_PROCESSOR_ID
43#else
44	mrc	p15, 0, r9, c0, c0		@ get processor id
45#endif
46	bl	__lookup_processor_type		@ r5=procinfo r9=cpuid
47	movs	r10, r5				@ invalid processor (r5=0)?
48	beq	__error_p				@ yes, error 'p'
49	bl	__lookup_machine_type		@ r5=machinfo
50	movs	r8, r5				@ invalid machine (r5=0)?
51	beq	__error_a			@ yes, error 'a'
52
53	ldr	r13, __switch_data		@ address to jump to after
54						@ the initialization is done
55	adr	lr, __after_proc_init		@ return (PIC) address
56	add	pc, r10, #PROCINFO_INITFUNC
57
58/*
59 * Set the Control Register and Read the process ID.
60 */
61	.type	__after_proc_init, %function
62__after_proc_init:
63#ifdef CONFIG_CPU_CP15
64	mrc	p15, 0, r0, c1, c0, 0		@ read control reg
65#ifdef CONFIG_ALIGNMENT_TRAP
66	orr	r0, r0, #CR_A
67#else
68	bic	r0, r0, #CR_A
69#endif
70#ifdef CONFIG_CPU_DCACHE_DISABLE
71	bic	r0, r0, #CR_C
72#endif
73#ifdef CONFIG_CPU_BPREDICT_DISABLE
74	bic	r0, r0, #CR_Z
75#endif
76#ifdef CONFIG_CPU_ICACHE_DISABLE
77	bic	r0, r0, #CR_I
78#endif
79#ifdef CONFIG_CPU_HIGH_VECTOR
80	orr	r0, r0, #CR_V
81#else
82	bic	r0, r0, #CR_V
83#endif
84	mcr	p15, 0, r0, c1, c0, 0		@ write control reg
85#endif /* CONFIG_CPU_CP15 */
86
87	mov	pc, r13				@ clear the BSS and jump
88						@ to start_kernel
89	.ltorg
90
91#include "head-common.S"
92