arch/cris/boot/rescue/head_v10.S

   1 /*
   2  * Rescue code, made to reside at the beginning of the
   3  * flash-memory. when it starts, it checks a partition
   4  * table at the first sector after the rescue sector.
   5  * the partition table was generated by the product builder
   6  * script and contains offsets, lengths, types and checksums
   7  * for each partition that this code should check.
   8  *
   9  * If any of the checksums fail, we assume the flash is so
  10  * corrupt that we can't use it to boot into the ftp flash
  11  * loader, and instead we initialize the serial port to
  12  * receive a flash-loader and new flash image. we dont include
  13  * any flash code here, but just accept a certain amount of
  14  * bytes from the serial port and jump into it. the downloaded
  15  * code is put in the cache.
  16  *
  17  * The partitiontable is designed so that it is transparent to
  18  * code execution - it has a relative branch opcode in the
  19  * beginning that jumps over it. each entry contains extra
  20  * data so we can add stuff later.
  21  *
  22  * Partition table format:
  23  *
  24  *     Code transparency:
  25  *
  26  *     2 bytes    [opcode 'nop']
  27  *     2 bytes    [opcode 'di']
  28  *     4 bytes    [opcode 'ba <offset>', 8-bit or 16-bit version]
  29  *     2 bytes    [opcode 'nop', delay slot]
  30  *
  31  *     Table validation (at +10):
  32  *
  33  *     2 bytes    [magic/version word for partitiontable - 0xef, 0xbe]
  34  *     2 bytes    [length of all entries plus the end marker]
  35  *     4 bytes    [checksum for the partitiontable itself]
  36  *
  37  *     Entries, each with the following format, last has offset -1:
  38  *
  39  *        4 bytes    [offset in bytes, from start of flash]
  40  *        4 bytes    [length in bytes of partition]
  41  *        4 bytes    [checksum, simple longword sum]
  42  *        2 bytes    [partition type]
  43  *        2 bytes    [flags, only bit 0 used, ro/rw = 1/0]
  44  *        16 bytes   [reserved for future use]
  45  *
  46  *     End marker
  47  *
  48  *        4 bytes    [-1]
  49  *
  50  *       10 bytes    [0, padding]
  51  *
  52  * Bit 0 in flags signifies RW or RO. The rescue code only bothers
  53  * to check the checksum for RO partitions, since the others will
  54  * change their data without updating the checksums. A 1 in bit 0
  55  * means RO, 0 means RW. That way, it is possible to set a partition
  56  * in RO mode initially, and later mark it as RW, since you can always
  57  * write 0's to the flash.
  58  *
  59  * During the wait for serial input, the status LED will flash so the
  60  * user knows something went wrong.
  61  *
  62  * Copyright (C) 1999-2007 Axis Communications AB
  63  */
  64
  65 #ifdef CONFIG_ETRAX_AXISFLASHMAP
  66
  67 #define ASSEMBLER_MACROS_ONLY
  68 #include <arch/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.
  78         ;; The length is enough for downloading code that loads the rest
  79         ;; of itself (after having setup the DRAM etc).
  80         ;; It is the same length as the on-chip ROM loads, so the same
  81         ;; host loader can be used to load a rescued product as well as
  82         ;; one booted through the Etrax serial boot code.
  83
  84 #define CODE_START 0x40000000
  85 #define CODE_LENGTH 784
  86
  87 #ifdef CONFIG_ETRAX_RESCUE_SER0
  88 #define SERXOFF R_SERIAL0_XOFF
  89 #define SERBAUD R_SERIAL0_BAUD
  90 #define SERRECC R_SERIAL0_REC_CTRL
  91 #define SERRDAT R_SERIAL0_REC_DATA
  92 #define SERSTAT R_SERIAL0_STATUS
  93 #endif
  94 #ifdef CONFIG_ETRAX_RESCUE_SER1
  95 #define SERXOFF R_SERIAL1_XOFF
  96 #define SERBAUD R_SERIAL1_BAUD
  97 #define SERRECC R_SERIAL1_REC_CTRL
  98 #define SERRDAT R_SERIAL1_REC_DATA
  99 #define SERSTAT R_SERIAL1_STATUS
 100 #endif
 101 #ifdef CONFIG_ETRAX_RESCUE_SER2
 102 #define SERXOFF R_SERIAL2_XOFF
 103 #define SERBAUD R_SERIAL2_BAUD
 104 #define SERRECC R_SERIAL2_REC_CTRL
 105 #define SERRDAT R_SERIAL2_REC_DATA
 106 #define SERSTAT R_SERIAL2_STATUS
 107 #endif
 108 #ifdef CONFIG_ETRAX_RESCUE_SER3
 109 #define SERXOFF R_SERIAL3_XOFF
 110 #define SERBAUD R_SERIAL3_BAUD
 111 #define SERRECC R_SERIAL3_REC_CTRL
 112 #define SERRDAT R_SERIAL3_REC_DATA
 113 #define SERSTAT R_SERIAL3_STATUS
 114 #endif
 115
 116 #define NOP_DI 0xf025050f
 117 #define RAM_INIT_MAGIC 0x56902387
 118
 119         .text
 120
 121         ;; This is the entry point of the rescue code
 122         ;; 0x80000000 if loaded in flash (as it should be)
 123         ;; Since etrax actually starts at address 2 when booting from flash, we
 124         ;; put a nop (2 bytes) here first so we dont accidentally skip the di
 125
 126         nop
 127         di
 128
 129         jump    in_cache        ; enter cached area instead
 130 in_cache:
 131
 132
 133         ;; First put a jump test to give a possibility of upgrading the
 134         ;; rescue code without erasing/reflashing the sector.
 135         ;; We put a longword of -1 here and if it is not -1, we jump using
 136         ;; the value as jump target. Since we can always change 1's to 0's
 137         ;; without erasing the sector, it is possible to add new
 138         ;; code after this and altering the jumptarget in an upgrade.
 139
 140 jtcd:   move.d  [jumptarget], $r0
 141         cmp.d   0xffffffff, $r0
 142         beq     no_newjump
 143         nop
 144
 145         jump    [$r0]
 146
 147 jumptarget:
 148         .dword  0xffffffff      ; can be overwritten later to insert new code
 149
 150 no_newjump:
 151 #ifdef CONFIG_ETRAX_ETHERNET
 152         ;; Start MII clock to make sure it is running when tranceiver is reset
 153         move.d 0x3, $r0    ; enable = on, phy = mii_clk
 154         move.d $r0, [R_NETWORK_GEN_CONFIG]
 155 #endif
 156
 157         ;; We need to setup the bus registers before we start using the DRAM
 158 #include "../../../arch-v10/lib/dram_init.S"
 159
 160         ;; we now should go through the checksum-table and check the listed
 161         ;; partitions for errors.
 162
 163         move.d  PTABLE_START, $r3
 164         move.d  [$r3], $r0
 165         cmp.d   NOP_DI, $r0     ; make sure the nop/di is there...
 166         bne     do_rescue
 167         nop
 168
 169         ;; skip the code transparency block (10 bytes).
 170
 171         addq    10, $r3
 172
 173         ;; check for correct magic
 174
 175         move.w  [$r3+], $r0
 176         cmp.w   PTABLE_MAGIC, $r0
 177         bne     do_rescue       ; didn't recognize - trig rescue
 178         nop
 179
 180         ;; check for correct ptable checksum
 181
 182         movu.w  [$r3+], $r2     ; ptable length
 183         move.d  $r2, $r8        ; save for later, length of total ptable
 184         addq    28, $r8         ; account for the rest
 185         move.d  [$r3+], $r4     ; ptable checksum
 186         move.d  $r3, $r1
 187         jsr     checksum        ; r1 source, r2 length, returns in r0
 188
 189         cmp.d   $r0, $r4
 190         bne     do_rescue       ; didn't match - trig rescue
 191         nop
 192
 193         ;; ptable is ok. validate each entry.
 194
 195         moveq   -1, $r7
 196
 197 ploop:  move.d  [$r3+], $r1     ; partition offset (from ptable start)
 198         bne     notfirst        ; check if it is the partition containing ptable
 199         nop                     ; yes..
 200         move.d  $r8, $r1        ; for its checksum check, skip the ptable
 201         move.d  [$r3+], $r2     ; partition length
 202         sub.d   $r8, $r2        ; minus the ptable length
 203         ba      bosse
 204         nop
 205 notfirst:
 206         cmp.d   -1, $r1         ; the end of the ptable ?
 207         beq     flash_ok        ;   if so, the flash is validated
 208         move.d  [$r3+], $r2     ; partition length
 209 bosse:  move.d  [$r3+], $r5     ; checksum
 210         move.d  [$r3+], $r4     ; type and flags
 211         addq    16, $r3         ; skip the reserved bytes
 212         btstq   16, $r4         ; check ro flag
 213         bpl     ploop           ;   rw partition, skip validation
 214         nop
 215         btstq   17, $r4         ; check bootable flag
 216         bpl     1f
 217         nop
 218         move.d  $r1, $r7        ; remember boot partition offset
 219 1:
 220         add.d   PTABLE_START, $r1
 221
 222         jsr     checksum        ; checksum the partition
 223
 224         cmp.d   $r0, $r5
 225         beq     ploop           ; checksums matched, go to next entry
 226         nop
 227
 228         ;; otherwise fall through to the rescue code.
 229
 230 do_rescue:
 231         ;; setup port PA and PB default initial directions and data
 232         ;; (so we can flash LEDs, and so that DTR and others are set)
 233
 234         move.b  CONFIG_ETRAX_DEF_R_PORT_PA_DIR, $r0
 235         move.b  $r0, [R_PORT_PA_DIR]
 236         move.b  CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r0
 237         move.b  $r0, [R_PORT_PA_DATA]
 238
 239         move.b  CONFIG_ETRAX_DEF_R_PORT_PB_DIR, $r0
 240         move.b  $r0, [R_PORT_PB_DIR]
 241         move.b  CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r0
 242         move.b  $r0, [R_PORT_PB_DATA]
 243
 244         ;; setup the serial port at 115200 baud
 245
 246         moveq   0, $r0
 247         move.d  $r0, [SERXOFF]
 248
 249         move.b  0x99, $r0
 250         move.b  $r0, [SERBAUD]  ; 115.2kbaud for both transmit and receive
 251
 252         move.b  0x40, $r0       ; rec enable
 253         move.b  $r0, [SERRECC]
 254
 255         moveq   0, $r1          ; "timer" to clock out a LED red flash
 256         move.d  CODE_START, $r3 ; destination counter
 257         movu.w  CODE_LENGTH, $r4; length
 258
 259 wait_ser:
 260         addq    1, $r1
 261 #ifndef CONFIG_ETRAX_NO_LEDS
 262 #ifdef CONFIG_ETRAX_PA_LEDS
 263         move.b  CONFIG_ETRAX_DEF_R_PORT_PA_DATA, $r2
 264 #endif
 265 #ifdef CONFIG_ETRAX_PB_LEDS
 266         move.b  CONFIG_ETRAX_DEF_R_PORT_PB_DATA, $r2
 267 #endif
 268         move.d  (1 << CONFIG_ETRAX_LED1R) | (1 << CONFIG_ETRAX_LED2R), $r0
 269         btstq   16, $r1
 270         bpl     1f
 271         nop
 272         or.d    $r0, $r2        ; set bit
 273         ba      2f
 274         nop
 275 1:      not     $r0             ; clear bit
 276         and.d   $r0, $r2
 277 2:
 278 #ifdef CONFIG_ETRAX_PA_LEDS
 279         move.b  $r2, [R_PORT_PA_DATA]
 280 #endif
 281 #ifdef CONFIG_ETRAX_PB_LEDS
 282         move.b  $r2, [R_PORT_PB_DATA]
 283 #endif
 284 #endif
 285
 286         ;; check if we got something on the serial port
 287
 288         move.b  [SERSTAT], $r0
 289         btstq   0, $r0          ; data_avail
 290         bpl     wait_ser
 291         nop
 292
 293         ;; got something - copy the byte and loop
 294
 295         move.b  [SERRDAT], $r0
 296         move.b  $r0, [$r3+]
 297
 298         subq    1, $r4          ; decrease length
 299         bne     wait_ser
 300         nop
 301
 302         ;; jump into downloaded code
 303
 304         move.d  RAM_INIT_MAGIC, $r8     ; Tell next product that DRAM is
 305                                         ; initialized
 306         jump    CODE_START
 307
 308 flash_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
 315 1:
 316         move.d  RAM_INIT_MAGIC, $r8     ; Tell next product that DRAM is
 317                                         ; initialized
 318         jump    $r7             ; boot!
 319
 320
 321         ;; Helper subroutines
 322
 323         ;; Will checksum by simple addition
 324         ;; r1 - source
 325         ;; r2 - length in bytes
 326         ;; result will be in r0
 327 checksum:
 328         moveq   0, $r0
 329         moveq   CONFIG_ETRAX_FLASH1_SIZE, $r6
 330
 331         ;; If the first physical flash memory is exceeded wrap to the
 332         ;; second one
 333         btstq   26, $r1         ; Are we addressing first flash?
 334         bpl     1f
 335         nop
 336         clear.d $r6
 337
 338 1:      test.d  $r6             ; 0 = no wrapping
 339         beq     2f
 340         nop
 341         lslq    20, $r6         ; Convert MB to bytes
 342         sub.d   $r1, $r6
 343
 344 2:      addu.b  [$r1+], $r0
 345         subq    1, $r6          ; Flash memory left
 346         beq     3f
 347         subq    1, $r2          ; Length left
 348         bne     2b
 349         nop
 350         ret
 351         nop
 352
 353 3:      move.d  MEM_CSE1_START, $r1 ; wrap to second flash
 354         ba      2b
 355         nop
 356
 357 #endif