1/* 2 * arch/cris/boot/compressed/head.S 3 * 4 * Copyright (C) 1999, 2001 Axis Communications AB 5 * 6 * Code that sets up the DRAM registers, calls the 7 * decompressor to unpack the piggybacked kernel, and jumps. 8 * 9 */ 10 11#define ASSEMBLER_MACROS_ONLY 12#include <asm/arch/sv_addr_ag.h> 13 14#define RAM_INIT_MAGIC 0x56902387 15#define COMMAND_LINE_MAGIC 0x87109563 16 17 ;; Exported symbols 18 19 .globl _input_data 20 21 22 .text 23 24 nop 25 di 26 27;; We need to initialze DRAM registers before we start using the DRAM 28 29 cmp.d RAM_INIT_MAGIC, r8 ; Already initialized? 30 beq dram_init_finished 31 nop 32 33#include "../../lib/dram_init.S" 34 35dram_init_finished: 36 37 ;; Initiate the PA and PB ports 38 39 move.b CONFIG_ETRAX_DEF_R_PORT_PA_DATA, r0 40 move.b r0, [R_PORT_PA_DATA] 41 42 move.b CONFIG_ETRAX_DEF_R_PORT_PA_DIR, r0 43 move.b r0, [R_PORT_PA_DIR] 44 45 move.b CONFIG_ETRAX_DEF_R_PORT_PB_DATA, r0 46 move.b r0, [R_PORT_PB_DATA] 47 48 move.b CONFIG_ETRAX_DEF_R_PORT_PB_DIR, r0 49 move.b r0, [R_PORT_PB_DIR] 50 51 ;; Setup the stack to a suitably high address. 52 ;; We assume 8 MB is the minimum DRAM in an eLinux 53 ;; product and put the sp at the top for now. 54 55 move.d 0x40800000, sp 56 57 ;; Figure out where the compressed piggyback image is 58 ;; in the flash (since we wont try to copy it to DRAM 59 ;; before unpacking). It is at _edata, but in flash. 60 ;; Use (_edata - basse) as offset to the current PC. 61 62basse: move.d pc, r5 63 and.d 0x7fffffff, r5 ; strip any non-cache bit 64 subq 2, r5 ; compensate for the move.d pc instr 65 move.d r5, r0 ; save for later - flash address of 'basse' 66 add.d _edata, r5 67 sub.d basse, r5 ; r5 = flash address of '_edata' 68 69 ;; Copy text+data to DRAM 70 71 move.d basse, r1 ; destination 72 move.d _edata, r2 ; end destination 731: move.w [r0+], r3 74 move.w r3, [r1+] 75 cmp.d r2, r1 76 bcs 1b 77 nop 78 79 move.d r5, [_input_data] ; for the decompressor 80 81 82 ;; Clear the decompressors BSS (between _edata and _end) 83 84 moveq 0, r0 85 move.d _edata, r1 86 move.d _end, r2 871: move.w r0, [r1+] 88 cmp.d r2, r1 89 bcs 1b 90 nop 91 92 ;; Save command line magic and address. 93 move.d _cmd_line_magic, $r12 94 move.d $r10, [$r12] 95 move.d _cmd_line_addr, $r12 96 move.d $r11, [$r12] 97 98 ;; Do the decompression and save compressed size in _inptr 99 100 jsr _decompress_kernel 101 102 ;; Put start address of root partition in r9 so the kernel can use it 103 ;; when mounting from flash 104 105 move.d [_input_data], r9 ; flash address of compressed kernel 106 add.d [_inptr], r9 ; size of compressed kernel 107 108 ;; Restore command line magic and address. 109 move.d _cmd_line_magic, $r10 110 move.d [$r10], $r10 111 move.d _cmd_line_addr, $r11 112 move.d [$r11], $r11 113 114 ;; Enter the decompressed kernel 115 move.d RAM_INIT_MAGIC, r8 ; Tell kernel that DRAM is initialized 116 jump 0x40004000 ; kernel is linked to this address 117 118 .data 119 120_input_data: 121 .dword 0 ; used by the decompressor 122_cmd_line_magic: 123 .dword 0 124_cmd_line_addr: 125 .dword 0 126#include "../../lib/hw_settings.S" 127