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 - 2003, Axis Communications AB 6 */ 7 8#define ASSEMBLER_MACROS_ONLY 9#include <asm/arch/hwregs/asm/reg_map_asm.h> 10#include <asm/arch/hwregs/asm/gio_defs_asm.h> 11#include <asm/arch/hwregs/asm/config_defs_asm.h> 12 13#define RAM_INIT_MAGIC 0x56902387 14#define COMMAND_LINE_MAGIC 0x87109563 15 16 ;; Exported symbols 17 18 .globl input_data 19 20 .text 21start: 22 di 23 24 ;; Start clocks for used blocks. 25 move.d REG_ADDR(config, regi_config, rw_clk_ctrl), $r1 26 move.d [$r1], $r0 27 or.d REG_STATE(config, rw_clk_ctrl, cpu, yes) | \ 28 REG_STATE(config, rw_clk_ctrl, bif, yes) | \ 29 REG_STATE(config, rw_clk_ctrl, fix_io, yes), $r0 30 move.d $r0, [$r1] 31 32 ;; If booting from NAND flash we first have to copy some 33 ;; data from NAND flash to internal RAM to get the code 34 ;; that initializes the SDRAM. Lets copy 20 KB. This 35 ;; code executes at 0x38010000 if booting from NAND and 36 ;; we are guaranted that at least 0x200 bytes are good so 37 ;; lets start from there. The first 8192 bytes in the nand 38 ;; flash is spliced with zeroes and is thus 16384 bytes. 39 move.d 0x38010200, $r10 40 move.d 0x14200, $r11 ; Start offset in NAND flash 0x10200 + 16384 41 move.d 0x5000, $r12 ; Length of copy 42 43 ;; Before this code the tools add a partitiontable so the PC 44 ;; has an offset from the linked address. 45offset1: 46 lapcq ., $r13 ; get PC 47 add.d first_copy_complete-offset1, $r13 48 49#include "../../lib/nand_init.S" 50 51first_copy_complete: 52 ;; Initialze the DRAM registers. 53 cmp.d RAM_INIT_MAGIC, $r8 ; Already initialized? 54 beq dram_init_finished 55 nop 56 57#include "../../lib/dram_init.S" 58 59dram_init_finished: 60 lapcq ., $r13 ; get PC 61 add.d second_copy_complete-dram_init_finished, $r13 62 63 move.d REG_ADDR(config, regi_config, r_bootsel), $r0 64 move.d [$r0], $r0 65 and.d REG_MASK(config, r_bootsel, boot_mode), $r0 66 cmp.d REG_STATE(config, r_bootsel, boot_mode, nand), $r0 67 bne second_copy_complete ; No NAND boot 68 nop 69 70 ;; Copy 2MB from NAND flash to SDRAM (at 2-4MB into the SDRAM) 71 move.d 0x40204000, $r10 72 move.d 0x8000, $r11 73 move.d 0x200000, $r12 74 ba copy_nand_to_ram 75 nop 76second_copy_complete: 77 78 ;; Initiate the PA port. 79 move.d CONFIG_ETRAX_DEF_GIO_PA_OUT, $r0 80 move.d REG_ADDR(gio, regi_gio, rw_pa_dout), $r1 81 move.d $r0, [$r1] 82 83 move.d CONFIG_ETRAX_DEF_GIO_PA_OE, $r0 84 move.d REG_ADDR(gio, regi_gio, rw_pa_oe), $r1 85 move.d $r0, [$r1] 86 87 ;; Setup the stack to a suitably high address. 88 ;; We assume 8 MB is the minimum DRAM and put 89 ;; the SP at the top for now. 90 91 move.d 0x40800000, $sp 92 93 ;; Figure out where the compressed piggyback image is 94 ;; in the flash (since we wont try to copy it to DRAM 95 ;; before unpacking). It is at _edata, but in flash. 96 ;; Use (_edata - herami) as offset to the current PC. 97 98 move.d REG_ADDR(config, regi_config, r_bootsel), $r0 99 move.d [$r0], $r0 100 and.d REG_MASK(config, r_bootsel, boot_mode), $r0 101 cmp.d REG_STATE(config, r_bootsel, boot_mode, nand), $r0 102 beq hereami2 103 nop 104hereami: 105 lapcq ., $r5 ; get PC 106 and.d 0x7fffffff, $r5 ; strip any non-cache bit 107 move.d $r5, $r0 ; save for later - flash address of 'herami' 108 add.d _edata, $r5 109 sub.d hereami, $r5 ; r5 = flash address of '_edata' 110 move.d hereami, $r1 ; destination 111 ba 2f 112 nop 113hereami2: 114 lapcq ., $r5 ; get PC 115 and.d 0x00ffffff, $r5 ; strip any non-cache bit 116 move.d $r5, $r6 117 or.d 0x40200000, $r6 118 move.d $r6, $r0 ; save for later - flash address of 'herami' 119 add.d _edata, $r5 120 sub.d hereami2, $r5 ; r5 = flash address of '_edata' 121 add.d 0x40200000, $r5 122 move.d hereami2, $r1 ; destination 1232: 124 ;; Copy text+data to DRAM 125 126 move.d _edata, $r2 ; end destination 1271: move.w [$r0+], $r3 128 move.w $r3, [$r1+] 129 cmp.d $r2, $r1 130 bcs 1b 131 nop 132 133 move.d input_data, $r0 ; for the decompressor 134 move.d $r5, [$r0] ; for the decompressor 135 136 ;; Clear the decompressors BSS (between _edata and _end) 137 138 moveq 0, $r0 139 move.d _edata, $r1 140 move.d _end, $r2 1411: move.w $r0, [$r1+] 142 cmp.d $r2, $r1 143 bcs 1b 144 nop 145 146 ;; Save command line magic and address. 147 move.d _cmd_line_magic, $r12 148 move.d $r10, [$r12] 149 move.d _cmd_line_addr, $r12 150 move.d $r11, [$r12] 151 152 ;; Do the decompression and save compressed size in _inptr 153 154 jsr decompress_kernel 155 nop 156 157 ;; Restore command line magic and address. 158 move.d _cmd_line_magic, $r10 159 move.d [$r10], $r10 160 move.d _cmd_line_addr, $r11 161 move.d [$r11], $r11 162 163 ;; Put start address of root partition in r9 so the kernel can use it 164 ;; when mounting from flash 165 move.d input_data, $r0 166 move.d [$r0], $r9 ; flash address of compressed kernel 167 move.d inptr, $r0 168 add.d [$r0], $r9 ; size of compressed kernel 169 cmp.d 0x40200000, $r9 170 blo enter_kernel 171 nop 172 sub.d 0x40200000, $r9 173 add.d 0x4000, $r9 174 175enter_kernel: 176 ;; Enter the decompressed kernel 177 move.d RAM_INIT_MAGIC, $r8 ; Tell kernel that DRAM is initialized 178 jump 0x40004000 ; kernel is linked to this address 179 nop 180 181 .data 182 183input_data: 184 .dword 0 ; used by the decompressor 185_cmd_line_magic: 186 .dword 0 187_cmd_line_addr: 188 .dword 0 189is_nand_boot: 190 .dword 0 191 192#include "../../lib/hw_settings.S" 193