1/* $Id: head.S,v 1.1.1.1 2008/10/15 03:26:00 james26_jang Exp $ 2 * 3 * Rescue code, made to reside at the beginning of the 4 * flash-memory. when it starts, it checks a partition 5 * table at the first sector after the rescue sector. 6 * the partition table was generated by the product builder 7 * script and contains offsets, lengths, types and checksums 8 * for each partition that this code should check. 9 * 10 * If any of the checksums fail, we assume the flash is so 11 * corrupt that we cant use it to boot into the ftp flash 12 * loader, and instead we initialize the serial port to 13 * receive a flash-loader and new flash image. we dont include 14 * any flash code here, but just accept a certain amount of 15 * bytes from the serial port and jump into it. the downloaded 16 * code is put in the cache. 17 * 18 * The partitiontable is designed so that it is transparent to 19 * code execution - it has a relative branch opcode in the 20 * beginning that jumps over it. each entry contains extra 21 * data so we can add stuff later. 22 * 23 * Partition table format: 24 * 25 * Code transparency: 26 * 27 * 2 bytes [opcode 'nop'] 28 * 2 bytes [opcode 'di'] 29 * 4 bytes [opcode 'ba <offset>', 8-bit or 16-bit version] 30 * 2 bytes [opcode 'nop', delay slot] 31 * 32 * Table validation (at +10): 33 * 34 * 2 bytes [magic/version word for partitiontable - 0xef, 0xbe] 35 * 2 bytes [length of all entries plus the end marker] 36 * 4 bytes [checksum for the partitiontable itself] 37 * 38 * Entries, each with the following format, last has offset -1: 39 * 40 * 4 bytes [offset in bytes, from start of flash] 41 * 4 bytes [length in bytes of partition] 42 * 4 bytes [checksum, simple longword sum] 43 * 2 bytes [partition type] 44 * 2 bytes [flags, only bit 0 used, ro/rw = 1/0] 45 * 16 bytes [reserved for future use] 46 * 47 * End marker 48 * 49 * 4 bytes [-1] 50 * 51 * 10 bytes [0, padding] 52 * 53 * Bit 0 in flags signifies RW or RO. The rescue code only bothers 54 * to check the checksum for RO partitions, since the others will 55 * change its data without updating the checksums. A 1 in bit 0 56 * means RO, 0 means RW. That way, it is possible to set a partition 57 * in RO mode initially, and later mark it as RW, since you can always 58 * write 0's to the flash. 59 * 60 * During the wait for serial input, the status LED will flash so the 61 * user knows something went wrong. 62 * 63 * Copyright (C) 1999,2001 Axis Communications AB 64 */ 65 66#include <linux/config.h> 67#define ASSEMBLER_MACROS_ONLY 68#include <asm/sv_addr_ag.h> 69 70 ;; The partitiontable is looked for at the first sector after the boot 71 ;; sector. Sector size is 65536 bytes in all flashes we use. 72 73#define PTABLE_START CONFIG_ETRAX_PTABLE_SECTOR 74#define PTABLE_MAGIC 0xbeef 75 76 ;; The normal Etrax100 on-chip boot ROM does serial boot at 0x380000f0. 77 ;; That is not where we put our downloaded serial boot-code. The length is 78 ;; enough for downloading code that loads the rest of itself (after 79 ;; having setup the DRAM etc). It is the same length as the on-chip 80 ;; ROM loads, so the same host loader can be used to load a rescued 81 ;; product as well as one booted through the Etrax serial boot code. 82 83#define CODE_START 0x40000000 84#define CODE_LENGTH 784 85 86#ifdef CONFIG_ETRAX_RESCUE_SER0 87#define SERXOFF R_SERIAL0_XOFF 88#define SERBAUD R_SERIAL0_BAUD 89#define SERRECC R_SERIAL0_REC_CTRL 90#define SERRDAT R_SERIAL0_REC_DATA 91#define SERSTAT R_SERIAL0_STATUS 92#endif 93#ifdef CONFIG_ETRAX_RESCUE_SER1 94#define SERXOFF R_SERIAL1_XOFF 95#define SERBAUD R_SERIAL1_BAUD 96#define SERRECC R_SERIAL1_REC_CTRL 97#define SERRDAT R_SERIAL1_REC_DATA 98#define SERSTAT R_SERIAL1_STATUS 99#endif 100#ifdef CONFIG_ETRAX_RESCUE_SER2 101#define SERXOFF R_SERIAL2_XOFF 102#define SERBAUD R_SERIAL2_BAUD 103#define SERRECC R_SERIAL2_REC_CTRL 104#define SERRDAT R_SERIAL2_REC_DATA 105#define SERSTAT R_SERIAL2_STATUS 106#endif 107#ifdef CONFIG_ETRAX_RESCUE_SER3 108#define SERXOFF R_SERIAL3_XOFF 109#define SERBAUD R_SERIAL3_BAUD 110#define SERRECC R_SERIAL3_REC_CTRL 111#define SERRDAT R_SERIAL3_REC_DATA 112#define SERSTAT R_SERIAL3_STATUS 113#endif 114 115#define NOP_DI 0xf025050f 116#define RAM_INIT_MAGIC 0x56902387 117 118 .text 119 120 ;; This is the entry point of the rescue code 121 ;; 0x80000000 if loaded in flash (as it should be) 122 ;; since etrax actually starts at address 2 when booting from flash, we 123 ;; put a nop (2 bytes) here first so we dont accidentally skip the di 124 125 nop 126 di 127 128 jump in_cache ; enter cached area instead 129in_cache: 130 131 ;; first put a jump test to give a possibility of upgrading the rescue code 132 ;; without erasing/reflashing the sector. we put a longword of -1 here and if 133 ;; its not -1, we jump using the value as jump target. since we can always 134 ;; change 1's to 0's without erasing the sector, it is possible to add new 135 ;; code after this and altering the jumptarget in an upgrade. 136 137jtcd: move.d [jumptarget], $r0 138 cmp.d 0xffffffff, $r0 139 beq no_newjump 140 nop 141 142 jump [$r0] 143 144jumptarget: 145 .dword 0xffffffff ; can be overwritten later to insert new code 146 147no_newjump: 148#ifdef CONFIG_ETRAX_ETHERNET 149 ;; Start MII clock to make sure it is running when tranceiver is reset 150 move.d 0x3, $r0 ; enable = on, phy = mii_clk 151 move.d $r0, [R_NETWORK_GEN_CONFIG] 152#endif 153 154 ;; We need to setup the bus registers before we start using the DRAM 155#include "../../lib/dram_init.S" 156 157 ;; we now should go through the checksum-table and check the listed 158 ;; partitions for errors. 159 160 move.d PTABLE_START, $r3 161 move.d [$r3], $r0 162 cmp.d NOP_DI, $r0 ; make sure the nop/di is there... 163 bne do_rescue 164 nop 165 166 ;; skip the code transparency block (10 bytes). 167 168 addq 10, $r3 169 170 ;; check for correct magic 171 172 move.w [$r3+], $r0 173 cmp.w PTABLE_MAGIC, $r0 174 bne do_rescue ; didn't recognize - trig rescue 175 nop 176 177 ;; check for correct ptable checksum 178 179 movu.w [$r3+], $r2 ; ptable length 180 move.d $r2, $r8 ; save for later, length of total ptable 181 addq 28, $r8 ; account for the rest 182 move.d [$r3+], $r4 ; ptable checksum 183 move.d $r3, $r1 184 jsr checksum ; r1 source, r2 length, returns in r0 185 186 cmp.d $r0, $r4 187 bne do_rescue ; didn't match - trig rescue 188 nop 189 190 ;; ptable is ok. validate each entry. 191 192 moveq -1, $r7 193 194ploop: move.d [$r3+], $r1 ; partition offset (from ptable start) 195 bne notfirst ; check if its the partition containing ptable 196 nop ; yes.. 197 move.d $r8, $r1 ; for its checksum check, skip the ptable 198 move.d [$r3+], $r2 ; partition length 199 sub.d $r8, $r2 ; minus the ptable length 200 ba bosse 201 nop 202notfirst: 203 cmp.d -1, $r1 ; the end of the ptable ? 204 beq flash_ok ; if so, the flash is validated 205 move.d [$r3+], $r2 ; partition length 206bosse: move.d [$r3+], $r5 ; checksum 207 move.d [$r3+], $r4 ; type and flags 208 addq 16, $r3 ; skip the reserved bytes 209 btstq 16, $r4 ; check ro flag 210 bpl ploop ; rw partition, skip validation 211 nop 212 btstq 17, $r4 ; check bootable flag 213 bpl 1f 214 nop 215 move.d $r1, $r7 ; remember boot partition offset 2161: 217 218 add.d PTABLE_START, $r1 219 220 jsr checksum ; checksum the partition 221 222 cmp.d $r0, $r5 223 beq ploop ; checksums matched, go to next entry 224 nop 225 226 ;; otherwise fall through to the rescue code. 227 228do_rescue: 229 ;; setup port PA and PB default initial directions and data 230 ;; (so we can flash LEDs, and so that DTR and others are set) 231 232 move.b CONFIG_ETRAX_DEF_R_PORT_PA_DIR, $r0 233 move.b $r0, [R_PORT_PA_DIR] 234 move.b CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r0 235 move.b $r0, [R_PORT_PA_DATA] 236 237 move.b CONFIG_ETRAX_DEF_R_PORT_PB_DIR, $r0 238 move.b $r0, [R_PORT_PB_DIR] 239 move.b CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r0 240 move.b $r0, [R_PORT_PB_DATA] 241 242 ;; setup the serial port at 115200 baud 243 244 moveq 0, $r0 245 move.d $r0, [SERXOFF] 246 247 move.b 0x99, $r0 248 move.b $r0, [SERBAUD] ; 115.2kbaud for both transmit and receive 249 250 move.b 0x40, $r0 ; rec enable 251 move.b $r0, [SERRECC] 252 253 moveq 0, $r1 ; "timer" to clock out a LED red flash 254 move.d CODE_START, $r3 ; destination counter 255 movu.w CODE_LENGTH, $r4; length 256 257wait_ser: 258 addq 1, $r1 259#ifndef CONFIG_ETRAX_NO_LEDS 260#ifdef CONFIG_ETRAX_PA_LEDS 261 move.b CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r2 262#endif 263#ifdef CONFIG_ETRAX_PB_LEDS 264 move.b CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r2 265#endif 266 move.d (1 << CONFIG_ETRAX_LED1R) | (1 << CONFIG_ETRAX_LED2R), $r0 267 btstq 16, $r1 268 bpl 1f 269 nop 270 or.d $r0, $r2 ; set bit 271 ba 2f 272 nop 2731: not $r0 ; clear bit 274 and.d $r0, $r2 2752: 276#ifdef CONFIG_ETRAX_PA_LEDS 277 move.b $r2, [R_PORT_PA_DATA] 278#endif 279#ifdef CONFIG_ETRAX_PB_LEDS 280 move.b $r2, [R_PORT_PB_DATA] 281#endif 282#ifdef CONFIG_ETRAX_90000000_LEDS 283 move.b $r2, [0x90000000] 284#endif 285#endif 286 287 ;; check if we got something on the serial port 288 289 move.b [SERSTAT], $r0 290 btstq 0, $r0 ; data_avail 291 bpl wait_ser 292 nop 293 294 ;; got something - copy the byte and loop 295 296 move.b [SERRDAT], $r0 297 move.b $r0, [$r3+] 298 299 subq 1, $r4 ; decrease length 300 bne wait_ser 301 nop 302 303 ;; jump into downloaded code 304 305 move.d RAM_INIT_MAGIC, $r8 ; Tell next product that DRAM is initialized 306 jump CODE_START 307 308flash_ok: 309 ;; check r7, which contains either -1 or the partition to boot from 310 311 cmp.d -1, $r7 312 bne 1f 313 nop 314 move.d PTABLE_START, $r7; otherwise use the ptable start 3151: 316 move.d RAM_INIT_MAGIC, $r8 ; Tell next product that DRAM is initialized 317 jump $r7 ; boot! 318 319 320 ;; Helper subroutines 321 322 ;; Will checksum by simple addition 323 ;; r1 - source 324 ;; r2 - length in bytes 325 ;; result will be in r0 326checksum: 327 moveq 0, $r0 3281: addu.b [$r1+], $r0 329 subq 1, $r2 330 bne 1b 331 nop 332 ret 333 nop 334