1 /* 2 * Copyright (C) 2009 Thomas Chou <thomas@wytron.com.tw> 3 * 4 * Based on arch/nios2/kernel/head.S 5 * 6 * This file is subject to the terms and conditions of the GNU General Public 7 * License. See the file "COPYING" in the main directory of this archive 8 * for more details. 9 * 10 */ 11 12 /* 13 * This code can be loaded anywhere, eg FLASH ROM as reset vector, 14 * as long as output does not overlap it. 15 */ 16 17 #include <linux/linkage.h> 18 #include <asm/cache.h> 19 20 .text 21 .set noat 22 ENTRY(_start) 23 wrctl status, r0 /* disable interrupt */ 24 /* invalidate all instruction cache */ 25 movia r1, NIOS2_ICACHE_SIZE 26 movui r2, NIOS2_ICACHE_LINE_SIZE 27 1: initi r1 28 sub r1, r1, r2 29 bgt r1, r0, 1b 30 /* invalidate all data cache */ 31 movia r1, NIOS2_DCACHE_SIZE 32 movui r2, NIOS2_DCACHE_LINE_SIZE 33 1: initd 0(r1) 34 sub r1, r1, r2 35 bgt r1, r0, 1b 36 37 nextpc r1 /* Find out where we are */ 38 chkadr: 39 movia r2, chkadr 40 beq r1, r2, finish_move /* We are running in correct address, 41 done */ 42 /* move code, r1: src, r2: dest, r3: last dest */ 43 addi r1, r1, (_start - chkadr) /* Source */ 44 movia r2, _start /* Destination */ 45 movia r3, __bss_start /* End of copy */ 46 1: ldw r8, 0(r1) /* load a word from [r1] */ 47 stw r8, 0(r2) /* stort a word to dest [r2] */ 48 addi r1, r1, 4 /* inc the src addr */ 49 addi r2, r2, 4 /* inc the dest addr */ 50 blt r2, r3, 1b 51 /* flush the data cache after moving */ 52 movia r1, NIOS2_DCACHE_SIZE 53 movui r2, NIOS2_DCACHE_LINE_SIZE 54 1: flushd 0(r1) 55 sub r1, r1, r2 56 bgt r1, r0, 1b 57 movia r1, finish_move 58 jmp r1 /* jmp to linked address */ 59 60 finish_move: 61 /* zero out the .bss segment (uninitialized common data) */ 62 movia r2, __bss_start /* presume nothing is between */ 63 movia r1, _end /* the .bss and _end. */ 64 1: stb r0, 0(r2) 65 addi r2, r2, 1 66 bne r1, r2, 1b 67 /* 68 * set up the stack pointer, some where higher than _end. 69 * The stack space must be greater than 32K for decompress. 70 */ 71 movia sp, 0x10000 72 add sp, sp, r1 73 /* save args passed from u-boot, maybe */ 74 addi sp, sp, -16 75 stw r4, 0(sp) 76 stw r5, 4(sp) 77 stw r6, 8(sp) 78 stw r7, 12(sp) 79 /* decompress the kernel */ 80 call decompress_kernel 81 /* pass saved args to kernel */ 82 ldw r4, 0(sp) 83 ldw r5, 4(sp) 84 ldw r6, 8(sp) 85 ldw r7, 12(sp) 86 87 /* flush all data cache after decompressing */ 88 movia r1, NIOS2_DCACHE_SIZE 89 movui r2, NIOS2_DCACHE_LINE_SIZE 90 1: flushd 0(r1) 91 sub r1, r1, r2 92 bgt r1, r0, 1b 93 /* flush all instruction cache */ 94 movia r1, NIOS2_ICACHE_SIZE 95 movui r2, NIOS2_ICACHE_LINE_SIZE 96 1: flushi r1 97 sub r1, r1, r2 98 bgt r1, r0, 1b 99 flushp 100 /* jump to start real kernel */ 101 movia r1, (CONFIG_NIOS2_MEM_BASE | CONFIG_NIOS2_KERNEL_REGION_BASE) 102 jmp r1 103 104 .balign 512 105 fake_headers_as_bzImage: 106 .short 0 107 .ascii "HdrS" 108 .short 0x0202 109 .short 0 110 .short 0 111 .byte 0x00, 0x10 112 .short 0 113 .byte 0 114 .byte 1 115 .byte 0x00, 0x80 116 .long 0 117 .long 0 118