| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm26/kernel/head.S |
| 3 | * |
| 4 | * Copyright (C) 1994-2000 Russell King |
| 5 | * Copyright (C) 2003 Ian Molton |
| 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 | * 26-bit kernel startup code |
| 12 | */ |
| 13 | #include <linux/config.h> |
| 14 | #include <linux/linkage.h> |
| 15 | #include <asm/mach-types.h> |
| 16 | |
| 17 | .globl swapper_pg_dir |
| 18 | .equ swapper_pg_dir, 0x0207d000 |
| 19 | |
| 20 | /* |
| 21 | * Entry point. |
| 22 | */ |
| 23 | .section ".init.text",#alloc,#execinstr |
| 24 | ENTRY(stext) |
| 25 | |
| 26 | __entry: |
| 27 | cmp pc, #0x02000000 |
| 28 | ldrlt pc, LC0 @ if 0x01800000, call at 0x02080000 |
| 29 | teq r0, #0 @ Check for old calling method |
| 30 | blne oldparams @ Move page if old |
| 31 | |
| 32 | adr r0, LC0 |
| 33 | ldmib r0, {r2-r5, sp} @ Setup stack (and fetch other values) |
| 34 | |
| 35 | mov r0, #0 @ Clear BSS |
| 36 | 1: cmp r2, r3 |
| 37 | strcc r0, [r2], #4 |
| 38 | bcc 1b |
| 39 | |
| 40 | bl detect_proc_type |
| 41 | str r0, [r4] |
| 42 | bl detect_arch_type |
| 43 | str r0, [r5] |
| 44 | |
| 45 | #ifdef CONFIG_XIP_KERNEL |
| 46 | ldr r3, ETEXT @ data section copy |
| 47 | ldr r4, SDATA |
| 48 | ldr r5, EDATA |
| 49 | 1: |
| 50 | ldr r6, [r3], #4 |
| 51 | str r6, [r4], #4 |
| 52 | cmp r4, r5 |
| 53 | blt 1b |
| 54 | #endif |
| 55 | mov fp, #0 |
| 56 | b start_kernel |
| 57 | |
| 58 | LC0: .word _stext |
| 59 | .word __bss_start @ r2 |
| 60 | .word _end @ r3 |
| 61 | .word processor_id @ r4 |
| 62 | .word __machine_arch_type @ r5 |
| 63 | .word init_thread_union+8192 @ sp |
| 64 | #ifdef CONFIG_XIP_KERNEL |
| 65 | ETEXT: .word _endtext |
| 66 | SDATA: .word _sdata |
| 67 | EDATA: .word __bss_start |
| 68 | #endif |
| 69 | |
| 70 | arm2_id: .long 0x41560200 @ ARM2 and 250 dont have a CPUID |
| 71 | arm250_id: .long 0x41560250 @ So we create some after probing for them |
| 72 | .align |
| 73 | |
| 74 | oldparams: mov r4, #0x02000000 |
| 75 | add r3, r4, #0x00080000 |
| 76 | add r4, r4, #0x0007c000 |
| 77 | 1: ldmia r0!, {r5 - r12} |
| 78 | stmia r4!, {r5 - r12} |
| 79 | cmp r4, r3 |
| 80 | blt 1b |
| 81 | mov pc, lr |
| 82 | |
| 83 | /* |
| 84 | * We need some way to automatically detect the difference between |
| 85 | * these two machines. Unfortunately, it is not possible to detect |
| 86 | * the presence of the SuperIO chip, because that will hang the old |
| 87 | * Archimedes machines solid. |
| 88 | */ |
| 89 | /* DAG: Outdated, these have been combined !!!!!!! */ |
| 90 | detect_arch_type: |
| 91 | #if defined(CONFIG_ARCH_ARC) |
| 92 | mov r0, #MACH_TYPE_ARCHIMEDES |
| 93 | #elif defined(CONFIG_ARCH_A5K) |
| 94 | mov r0, #MACH_TYPE_A5K |
| 95 | #endif |
| 96 | mov pc, lr |
| 97 | |
| 98 | detect_proc_type: |
| 99 | mov ip, lr |
| 100 | mov r2, #0xea000000 @ Point undef instr to continuation |
| 101 | adr r0, continue - 12 |
| 102 | orr r0, r2, r0, lsr #2 |
| 103 | mov r1, #0 |
| 104 | str r0, [r1, #4] |
| 105 | ldr r0, arm2_id |
| 106 | swp r2, r2, [r1] @ check for swp (ARM2 cant) |
| 107 | ldr r0, arm250_id |
| 108 | mrc 15, 0, r3, c0, c0 @ check for CP#15 (ARM250 cant) |
| 109 | mov r0, r3 |
| 110 | continue: mov r2, #0xeb000000 @ Make undef vector loop |
| 111 | sub r2, r2, #2 |
| 112 | str r2, [r1, #4] |
| 113 | mov pc, ip |