1/* 2 * Code that sets up the DRAM registers, calls the 3 * decompressor to unpack the piggybacked kernel, and jumps. 4 * 5 * Copyright (C) 1999 - 2006, Axis Communications AB 6 */ 7 8#define ASSEMBLER_MACROS_ONLY 9#include <hwregs/asm/reg_map_asm.h> 10#include <mach/startup.inc> 11 12#define RAM_INIT_MAGIC 0x56902387 13#define COMMAND_LINE_MAGIC 0x87109563 14 15 ;; Exported symbols 16 17 .globl input_data 18 19 .text 20start: 21 di 22 23 ;; Start clocks for used blocks. 24 START_CLOCKS 25 26 ;; Initialize the DRAM registers. 27 cmp.d RAM_INIT_MAGIC, $r8 ; Already initialized? 28 beq dram_init_finished 29 nop 30 31#if defined CONFIG_ETRAXFS 32#include "../../arch-v32/mach-fs/dram_init.S" 33#elif defined CONFIG_CRIS_MACH_ARTPEC3 34#include "../../arch-v32/mach-a3/dram_init.S" 35#else 36#error Only ETRAXFS and ARTPEC-3 supported! 37#endif 38 39dram_init_finished: 40 41 GIO_INIT 42 ;; Setup the stack to a suitably high address. 43 ;; We assume 8 MB is the minimum DRAM and put 44 ;; the SP at the top for now. 45 46 move.d 0x40800000, $sp 47 48 ;; Figure out where the compressed piggyback image is. 49 ;; It is either in [NOR] flash (we don't want to copy it 50 ;; to DRAM before unpacking), or copied to DRAM 51 ;; by the [NAND] flash boot loader. 52 ;; The piggyback image is at _edata, but relative to where the 53 ;; image is actually located in memory, not where it is linked 54 ;; (the decompressor is linked at 0x40700000+ and runs there). 55 ;; Use (_edata - herami) as offset to the current PC. 56 57hereami: 58 lapcq ., $r5 ; get PC 59 and.d 0x7fffffff, $r5 ; strip any non-cache bit 60 move.d $r5, $r0 ; source address of 'herami' 61 add.d _edata, $r5 62 sub.d hereami, $r5 ; r5 = flash address of '_edata' 63 move.d hereami, $r1 ; destination 64 65 ;; Copy text+data to DRAM 66 67 move.d _edata, $r2 ; end destination 681: move.w [$r0+], $r3 ; from herami+ source 69 move.w $r3, [$r1+] ; to hereami+ destination (linked address) 70 cmp.d $r2, $r1 ; finish when destination == _edata 71 bcs 1b 72 nop 73 move.d input_data, $r0 ; for the decompressor 74 move.d $r5, [$r0] ; for the decompressor 75 76 ;; Clear the decompressors BSS (between _edata and _end) 77 78 moveq 0, $r0 79 move.d _edata, $r1 80 move.d _end, $r2 811: move.w $r0, [$r1+] 82 cmp.d $r2, $r1 83 bcs 1b 84 nop 85 86 ;; Save command line magic and address. 87 move.d _cmd_line_magic, $r0 88 move.d $r10, [$r0] 89 move.d _cmd_line_addr, $r0 90 move.d $r11, [$r0] 91 92 ;; Save boot source indicator 93 move.d _boot_source, $r0 94 move.d $r12, [$r0] 95 96 ;; Do the decompression and save compressed size in _inptr 97 98 jsr decompress_kernel 99 nop 100 101 ;; Restore boot source indicator 102 move.d _boot_source, $r12 103 move.d [$r12], $r12 104 105 ;; Restore command line magic and address. 106 move.d _cmd_line_magic, $r10 107 move.d [$r10], $r10 108 move.d _cmd_line_addr, $r11 109 move.d [$r11], $r11 110 111 ;; Put start address of root partition in r9 so the kernel can use it 112 ;; when mounting from flash 113 move.d input_data, $r0 114 move.d [$r0], $r9 ; flash address of compressed kernel 115 move.d inptr, $r0 116 add.d [$r0], $r9 ; size of compressed kernel 117 cmp.d 0x40000000, $r9 ; image in DRAM ? 118 blo enter_kernel ; no, must be [NOR] flash, jump 119 nop ; delay slot 120 and.d 0x001fffff, $r9 ; assume compressed kernel was < 2M 121 122enter_kernel: 123 ;; Enter the decompressed kernel 124 move.d RAM_INIT_MAGIC, $r8 ; Tell kernel that DRAM is initialized 125 jump 0x40004000 ; kernel is linked to this address 126 nop 127 128 .data 129 130input_data: 131 .dword 0 ; used by the decompressor 132_cmd_line_magic: 133 .dword 0 134_cmd_line_addr: 135 .dword 0 136_boot_source: 137 .dword 0 138 139#if defined CONFIG_ETRAXFS 140#include "../../arch-v32/mach-fs/hw_settings.S" 141#elif defined CONFIG_CRIS_MACH_ARTPEC3 142#include "../../arch-v32/mach-a3/hw_settings.S" 143#else 144#error Only ETRAXFS and ARTPEC-3 supported! 145#endif 146