doc/README.rockchip

   1 # SPDX-License-Identifier: GPL-2.0+
   2 #
   3 # Copyright (C) 2015 Google. Inc
   4 # Written by Simon Glass <sjg@chromium.org>
   5
   6 U-Boot on Rockchip
   7 ==================
   8
   9 A wide range of Rockchip SoCs are supported in mainline U-Boot
  10
  11
  12 Prerequisites
  13 =============
  14
  15 You will need:
  16
  17    - Firefly RK3288 board or something else with a supported RockChip SoC
  18    - Power connection to 5V using the supplied micro-USB power cable
  19    - Separate USB serial cable attached to your computer and the Firefly
  20         (connect to the micro-USB connector below the logo)
  21    - rkflashtool [3]
  22    - openssl (sudo apt-get install openssl)
  23    - Serial UART connection [4]
  24    - Suitable ARM cross compiler, e.g.:
  25         sudo apt-get install gcc-4.7-arm-linux-gnueabi
  26
  27
  28 Building
  29 ========
  30
  31 At present 12 RK3288 boards are supported:
  32
  33    - EVB RK3288 - use evb-rk3288 configuration
  34    - Fennec RK3288 - use fennec-rk3288 configuration
  35    - Firefly RK3288 - use firefly-rk3288 configuration
  36    - Hisense Chromebook - use chromebook_jerry configuration
  37    - Asus C100P Chromebook - use chromebook_minnie configuration
  38    - Asus Chromebit - use chromebook_mickey configuration
  39    - MiQi RK3288 - use miqi-rk3288 configuration
  40    - phyCORE-RK3288 RDK - use phycore-rk3288 configuration
  41    - PopMetal RK3288 - use popmetal-rk3288 configuration
  42    - Radxa Rock 2 - use rock2 configuration
  43    - Tinker RK3288 - use tinker-rk3288 configuration
  44    - Vyasa RK3288 - use vyasa-rk3288 configuration
  45
  46 Two RK3036 boards are supported:
  47
  48    - EVB RK3036 - use evb-rk3036 configuration
  49    - Kylin - use kylin_rk3036 configuration
  50
  51 One RK3328 board is supported:
  52
  53    - EVB RK3328
  54
  55 Size RK3399 boards are supported (aarch64):
  56
  57    - EBV RK3399 - use evb_rk3399 configuration
  58    - Firefly RK3399 - use the firefly_rk3399 configuration
  59    - Puma - use puma_rk3399 configuration
  60    - Ficus - use ficus-rk3399 configuration
  61    - Rock960 (Vamrs) - use rock960-rk3399 configuration
  62    - Bob - use chromebook_bob configuration
  63
  64 Four RK3368 boards are supported:
  65
  66    - Sheep - use sheep-rk3368 configuration
  67    - Lion - use lion-rk3368 configuration
  68    - Geekbox - use geekbox configuration
  69    - EVB PX5 - use evb-px5  configuration
  70
  71 One RK3128 board is supported:
  72
  73    - EVB RK3128 - use evb-rk3128 configuration
  74
  75 One RK3229 board is supported:
  76
  77    - EVB RK3229 - use evb-rk3229 configuration
  78
  79 Two RV1108 boards are supported:
  80
  81    - EVB RV1108 - use evb-rv1108 configuration
  82    - Elgin R1 - use elgin-rv1108 configuration
  83
  84 One RV3188 baord is supported:
  85
  86    - Raxda Rock - use rock configuration
  87
  88
  89 For example:
  90
  91 1. To build RK3288 board:
  92
  93    CROSS_COMPILE=arm-linux-gnueabi- make O=firefly firefly-rk3288_defconfig all
  94
  95     (or you can use another cross compiler if you prefer)
  96
  97 2. To build RK3399 board:
  98
  99    Option 1: Package the image with Rockchip miniloader:
 100
 101    - Compile U-Boot
 102
 103      => cd /path/to/u-boot
 104      => make nanopi-neo4-rk3399_defconfig
 105      => make
 106      => make u-boot.itb
 107
 108    - Get the rkbin
 109
 110      => git clone https://github.com/rockchip-linux/rkbin.git
 111
 112    - Create trust.img
 113
 114      => cd /path/to/rkbin
 115      => ./tools/trust_merger RKTRUST/RK3399TRUST.ini
 116
 117    - Create uboot.img
 118
 119      => cd /path/to/rkbin
 120      => ./tools/loaderimage --pack --uboot /path/to/u-boot/u-boot-dtb.bin uboot.img
 121
 122      (Get trust.img and uboot.img)
 123
 124    Option 2: Package the image with SPL:
 125
 126    - We need the Python elftools.elf.elffile library for make_fit_atf.py to work
 127
 128      => sudo apt-get install python-pyelftools
 129
 130    - Export cross compiler path for aarch64
 131
 132    - Compile ATF
 133
 134      For Puma board.
 135
 136         => git clone git://git.theobroma-systems.com/arm-trusted-firmware.git
 137         => cd arm-trusted-firmware
 138         => make CROSS_COMPILE=aarch64-linux-gnu- PLAT=rk3399 bl31
 139
 140         (copy bl31.bin into U-Boot root dir)
 141         => cp build/rk3399/release/bl31/bl31.bin /path/to/u-boot/bl31-rk3399.bin
 142
 143      For rest of rk3399 boards.
 144
 145         => git clone https://github.com/ARM-software/arm-trusted-firmware.git
 146         => cd arm-trusted-firmware
 147
 148         (export cross compiler path for Cortex-M0 MCU likely arm-none-eabi-)
 149         => make realclean
 150         => make CROSS_COMPILE=aarch64-linux-gnu- PLAT=rk3399
 151
 152         (copy bl31.elf into U-Boot root dir)
 153         => cp build/rk3399/release/bl31/bl31.elf /path/to/u-boot
 154
 155    - Compile PMU M0 firmware
 156
 157      This is optional for most of the rk3399 boards and required only for Puma board.
 158
 159      => git clone git://git.theobroma-systems.com/rk3399-cortex-m0.git
 160      => cd rk3399-cortex-m0
 161
 162      (export cross compiler path for Cortex-M0 PMU)
 163      => make CROSS_COMPILE=arm-cortex_m0-eabi-
 164
 165      (copy rk3399m0.bin into U-Boot root dir)
 166      => cp rk3399m0.bin /path/to/u-boot
 167
 168    - Compile U-Boot
 169
 170      => cd /path/to/u-boot
 171      => make orangepi-rk3399_defconfig
 172      => make
 173      => make u-boot.itb
 174
 175      (Get spl/u-boot-spl-dtb.bin, u-boot.itb images and some boards would get
 176       spl/u-boot-spl.bin since it doesn't enable CONFIG_SPL_OF_CONTROL
 177
 178       If TPL enabled on the target, get tpl/u-boot-tpl-dtb.bin or tpl/u-boot-tpl.bin
 179       if CONFIG_TPL_OF_CONTROL not enabled)
 180
 181 Writing to the board with USB
 182 =============================
 183
 184 For USB to work you must get your board into ROM boot mode, either by erasing
 185 your MMC or (perhaps) holding the recovery button when you boot the board.
 186 To erase your MMC, you can boot into Linux and type (as root)
 187
 188    dd if=/dev/zero of=/dev/mmcblk0 bs=1M
 189
 190 Connect your board's OTG port to your computer.
 191
 192 To create a suitable image and write it to the board:
 193
 194    ./firefly-rk3288/tools/mkimage -n rk3288 -T rkimage -d \
 195         ./firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
 196    cat out | openssl rc4 -K 7c4e0304550509072d2c7b38170d1711 | rkflashtool l
 197
 198 If all goes well you should something like:
 199
 200    U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 10:06:49)
 201    Card did not respond to voltage select!
 202    spl: mmc init failed with error: -17
 203    ### ERROR ### Please RESET the board ###
 204
 205 You will need to reset the board before each time you try. Yes, that's all
 206 it does so far. If support for the Rockchip USB protocol or DFU were added
 207 in SPL then we could in principle load U-Boot and boot to a prompt from USB
 208 as several other platforms do. However it does not seem to be possible to
 209 use the existing boot ROM code from SPL.
 210
 211
 212 Booting from an SD card
 213 =======================
 214
 215 To write an image that boots from an SD card (assumed to be /dev/sdc):
 216
 217    ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \
 218         firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
 219    sudo dd if=out of=/dev/sdc seek=64 && \
 220    sudo dd if=firefly-rk3288/u-boot-dtb.img of=/dev/sdc seek=16384
 221
 222 This puts the Rockchip header and SPL image first and then places the U-Boot
 223 image at block 16384 (i.e. 8MB from the start of the SD card). This
 224 corresponds with this setting in U-Boot:
 225
 226    #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR      0x4000
 227
 228 Put this SD (or micro-SD) card into your board and reset it. You should see
 229 something like:
 230
 231    U-Boot 2016.01-rc2-00309-ge5bad3b-dirty (Jan 02 2016 - 23:41:59 -0700)
 232
 233    Model: Radxa Rock 2 Square
 234    DRAM:  2 GiB
 235    MMC:   dwmmc@ff0f0000: 0, dwmmc@ff0c0000: 1
 236    *** Warning - bad CRC, using default environment
 237
 238    In:    serial
 239    Out:   vop@ff940000.vidconsole
 240    Err:   serial
 241    Net:   Net Initialization Skipped
 242    No ethernet found.
 243    Hit any key to stop autoboot:  0
 244    =>
 245
 246 The rockchip bootrom can load and boot an initial spl, then continue to
 247 load a second-stage bootloader (ie. U-Boot) as soon as the control is returned
 248 to the bootrom. Both the RK3288 and the RK3036 use this special boot sequence.
 249 The configuration option enabling this is:
 250
 251         CONFIG_SPL_ROCKCHIP_BACK_TO_BROM=y
 252
 253 You can create the image via the following operations:
 254
 255    ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \
 256         firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
 257    cat firefly-rk3288/u-boot-dtb.bin >> out && \
 258    sudo dd if=out of=/dev/sdc seek=64
 259
 260 If you have an HDMI cable attached you should see a video console.
 261
 262 For evb_rk3036 board:
 263         ./evb-rk3036/tools/mkimage -n rk3036 -T rksd  -d evb-rk3036/spl/u-boot-spl.bin out && \
 264         cat evb-rk3036/u-boot-dtb.bin >> out && \
 265         sudo dd if=out of=/dev/sdc seek=64
 266
 267 Note: rk3036 SDMMC and debug uart use the same iomux, so if you boot from SD, the
 268       debug uart must be disabled
 269
 270
 271 Booting from an SD card on RK3288 with TPL
 272 ==========================================
 273
 274 Since the size of SPL can't be exceeded 0x8000 bytes in RK3288, it is not possible add
 275 new SPL features like Falcon mode or etc.
 276
 277 So introduce TPL so-that adding new features to SPL is possible because now TPL should
 278 run minimal with code like DDR, clock etc and rest of new features in SPL.
 279
 280 As of now TPL is added on Vyasa-RK3288 board.
 281
 282 To write an image that boots from an SD card (assumed to be /dev/mmcblk0):
 283
 284    ./tools/mkimage -n rk3288 -T rksd -d ./tpl/u-boot-tpl.bin out &&
 285     cat ./spl/u-boot-spl-dtb.bin >> out &&
 286     sudo dd if=out of=/dev/mmcblk0 seek=64 &&
 287     sudo dd if=u-boot-dtb.img of=/dev/mmcblk0 seek=16384
 288
 289 Booting from an SD card on RK3188
 290 =================================
 291
 292 For rk3188 boards the general storage onto the card stays the same as
 293 described above, but the image creation needs a bit more care.
 294
 295 The bootrom of rk3188 expects to find a small 1kb loader which returns
 296 control to the bootrom, after which it will load the real loader, which
 297 can then be up to 29kb in size and does the regular ddr init.  This is
 298 handled by a single image (built as the SPL stage) that tests whether
 299 it is handled for the first or second time via code executed from the
 300 boot0-hook.
 301
 302 Additionally the rk3188 requires everything the bootrom loads to be
 303 rc4-encrypted. Except for the very first stage the bootrom always reads
 304 and decodes 2kb pages, so files should be sized accordingly.
 305
 306 # copy tpl, pad to 1020 bytes and append spl
 307 tools/mkimage -n rk3188 -T rksd -d spl/u-boot-spl.bin out
 308
 309 # truncate, encode and append u-boot.bin
 310 truncate -s %2048 u-boot.bin
 311 cat u-boot.bin | split -b 512 --filter='openssl rc4 -K 7C4E0304550509072D2C7B38170D1711' >> out
 312
 313 Booting from an SD card on RK3399
 314 =================================
 315
 316 To write an image that boots from an SD card (assumed to be /dev/sdc):
 317
 318 Option 1: Package the image with Rockchip miniloader:
 319
 320   - Create idbloader.img
 321
 322     => cd /path/to/u-boot
 323     => ./tools/mkimage  -n rk3399 -T rksd -d /path/to/rkbin/bin/rk33/rk3399_ddr_800MHz_v1.20.bin idbloader.img
 324     => cat /path/to/rkbin/bin/rk33/rk3399_miniloader_v1.19.bin >> idbloader.img
 325
 326   - Write idbloader.img at 64 sector
 327
 328     => sudo dd if=idbloader.img of=/dev/sdc seek=64
 329
 330   - Write trust.img at 24576
 331
 332     => sudo dd if=trust.img of=/dev/sdc seek=24576
 333
 334   - Write uboot.img at 16384 sector
 335
 336     => sudo dd if=uboot.img of=/dev/sdc seek=16384
 337     => sync
 338
 339 Put this SD (or micro-SD) card into your board and reset it. You should see
 340 something like:
 341
 342 DDR Version 1.20 20190314
 343 In
 344 Channel 0: DDR3, 933MHz
 345 Bus Width=32 Col=10 Bank=8 Row=15 CS=1 Die Bus-Width=16 Size=1024MB
 346 no stride
 347 ch 0 ddrconfig = 0x101, ddrsize = 0x20
 348 pmugrf_os_reg[2] = 0x10006281, stride = 0x17
 349 OUT
 350 Boot1: 2019-03-14, version: 1.19
 351 CPUId = 0x0
 352 ChipType = 0x10, 239
 353 mmc: ERROR: SDHCI ERR:cmd:0x102,stat:0x18000
 354 mmc: ERROR: Card did not respond to voltage select!
 355 emmc reinit
 356 mmc: ERROR: SDHCI ERR:cmd:0x102,stat:0x18000
 357 mmc: ERROR: Card did not respond to voltage select!
 358 emmc reinit
 359 mmc: ERROR: SDHCI ERR:cmd:0x102,stat:0x18000
 360 mmc: ERROR: Card did not respond to voltage select!
 361 SdmmcInit=2 1
 362 mmc0:cmd5,20
 363 SdmmcInit=0 0
 364 BootCapSize=0
 365 UserCapSize=60543MB
 366 FwPartOffset=2000 , 0
 367 StorageInit ok = 45266
 368 SecureMode = 0
 369 SecureInit read PBA: 0x4
 370 SecureInit read PBA: 0x404
 371 SecureInit read PBA: 0x804
 372 SecureInit read PBA: 0xc04
 373 SecureInit read PBA: 0x1004
 374 SecureInit read PBA: 0x1404
 375 SecureInit read PBA: 0x1804
 376 SecureInit read PBA: 0x1c04
 377 SecureInit ret = 0, SecureMode = 0
 378 atags_set_bootdev: ret:(0)
 379 GPT 0x3380ec0 signature is wrong
 380 recovery gpt...
 381 GPT 0x3380ec0 signature is wrong
 382 recovery gpt fail!
 383 LoadTrust Addr:0x4000
 384 No find bl30.bin
 385 Load uboot, ReadLba = 2000
 386 hdr 0000000003380880 + 0x0:0x88,0x41,0x3e,0x97,0xe6,0x61,0x54,0x23,0xe9,0x5a,0xd1,0x2b,0xdc,0x2f,0xf9,0x35,
 387
 388 Load OK, addr=0x200000, size=0x9c9c0
 389 RunBL31 0x10000
 390 NOTICE:  BL31: v1.3(debug):370ab80
 391 NOTICE:  BL31: Built : 09:23:41, Mar  4 2019
 392 NOTICE:  BL31: Rockchip release version: v1.1
 393 INFO:    GICv3 with legacy support detected. ARM GICV3 driver initialized in EL3
 394 INFO:    Using opteed sec cpu_context!
 395 INFO:    boot cpu mask: 0
 396 INFO:    plat_rockchip_pmu_init(1181): pd status 3e
 397 INFO:    BL31: Initializing runtime services
 398 INFO:    BL31: Initializing BL32
 399 INF [0x0] TEE-CORE:init_primary_helper:337: Initializing (1.1.0-195-g8f090d20 #6 Fri Dec  7 06:11:20 UTC 2018 aarch64)
 400
 401 INF [0x0] TEE-CORE:init_primary_helper:338: Release version: 1.2
 402
 403 INF [0x0] TEE-CORE:init_teecore:83: teecore inits done
 404 INFO:    BL31: Preparing for EL3 exit to normal world
 405 INFO:    Entry point address = 0x200000
 406 INFO:    SPSR = 0x3c9
 407
 408
 409 U-Boot 2019.04-rc4-00136-gfd121f9641-dirty (Apr 16 2019 - 14:02:47 +0530)
 410
 411 Model: FriendlyARM NanoPi NEO4
 412 DRAM:  1022 MiB
 413 MMC:   dwmmc@fe310000: 2, dwmmc@fe320000: 1, sdhci@fe330000: 0
 414 Loading Environment from MMC... *** Warning - bad CRC, using default environment
 415
 416 In:    serial@ff1a0000
 417 Out:   serial@ff1a0000
 418 Err:   serial@ff1a0000
 419 Model: FriendlyARM NanoPi NEO4
 420 Net:   eth0: ethernet@fe300000
 421 Hit any key to stop autoboot:  0
 422 =>
 423
 424 Option 2: Package the image with SPL:
 425
 426   - Prefix rk3399 header to SPL image
 427
 428     => cd /path/to/u-boot
 429     => ./tools/mkimage -n rk3399 -T rksd -d spl/u-boot-spl-dtb.bin out
 430
 431   - Write prefixed SPL at 64th sector
 432
 433     => sudo dd if=out of=/dev/sdc seek=64
 434
 435   - Write U-Boot proper at 16384 sector
 436
 437     => sudo dd if=u-boot.itb of=/dev/sdc seek=16384
 438     => sync
 439
 440 Put this SD (or micro-SD) card into your board and reset it. You should see
 441 something like:
 442
 443 U-Boot SPL board init
 444 Trying to boot from MMC1
 445
 446
 447 U-Boot 2019.01-00004-g14db5ee998 (Mar 11 2019 - 13:18:41 +0530)
 448
 449 Model: Orange Pi RK3399 Board
 450 DRAM:  2 GiB
 451 MMC:   dwmmc@fe310000: 2, dwmmc@fe320000: 1, sdhci@fe330000: 0
 452 Loading Environment from MMC... OK
 453 In:    serial@ff1a0000
 454 Out:   serial@ff1a0000
 455 Err:   serial@ff1a0000
 456 Model: Orange Pi RK3399 Board
 457 Net:   eth0: ethernet@fe300000
 458 Hit any key to stop autoboot:  0
 459 =>
 460
 461 Option 3: Package the image with TPL:
 462
 463   - Prefix rk3399 header to TPL image
 464
 465     => cd /path/to/u-boot
 466     => ./tools/mkimage -n rk3399 -T rksd -d tpl/u-boot-tpl-dtb.bin out
 467
 468   - Concatinate tpl with spl
 469
 470     => cd /path/to/u-boot
 471     => cat ./spl/u-boot-spl-dtb.bin >> out
 472
 473   - Write tpl+spl at 64th sector
 474
 475     => sudo dd if=out of=/dev/sdc seek=64
 476
 477   - Write U-Boot proper at 16384 sector
 478
 479     => sudo dd if=u-boot.itb of=/dev/sdc seek=16384
 480     => sync
 481
 482 Put this SD (or micro-SD) card into your board and reset it. You should see
 483 something like:
 484
 485 U-Boot TPL board init
 486 Trying to boot from BOOTROM
 487 Returning to boot ROM...
 488
 489 U-Boot SPL board init
 490 Trying to boot from MMC1
 491
 492
 493 U-Boot 2019.07-rc1-00241-g5b3244767a (May 08 2019 - 10:51:06 +0530)
 494
 495 Model: Orange Pi RK3399 Board
 496 DRAM:  2 GiB
 497 MMC:   dwmmc@fe310000: 2, dwmmc@fe320000: 1, sdhci@fe330000: 0
 498 Loading Environment from MMC... OK
 499 In:    serial@ff1a0000
 500 Out:   serial@ff1a0000
 501 Err:   serial@ff1a0000
 502 Model: Orange Pi RK3399 Board
 503 Net:   eth0: ethernet@fe300000
 504 Hit any key to stop autoboot:  0
 505 =>
 506
 507 Using fastboot on rk3288
 508 ========================
 509 - Write GPT partition layout to mmc device which fastboot want to use it to
 510 store the image
 511
 512         => gpt write mmc 1 $partitions
 513
 514 - Invoke fastboot command to prepare
 515
 516         => fastboot 1
 517
 518 - Start fastboot request on PC
 519
 520         fastboot -i 0x2207 flash loader evb-rk3288/spl/u-boot-spl-dtb.bin
 521
 522 You should see something like:
 523
 524         => fastboot 1
 525         WARNING: unknown variable: partition-type:loader
 526         Starting download of 357796 bytes
 527         ..
 528         downloading of 357796 bytes finished
 529         Flashing Raw Image
 530         ........ wrote 357888 bytes to 'loader'
 531
 532 Booting from SPI
 533 ================
 534
 535 To write an image that boots from SPI flash (e.g. for the Haier Chromebook or
 536 Bob):
 537
 538    ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \
 539         -d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \
 540    dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \
 541    cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \
 542    dd if=out.bin of=out.bin.pad bs=4M conv=sync
 543
 544 This converts the SPL image to the required SPI format by adding the Rockchip
 545 header and skipping every second 2KB block. Then the U-Boot image is written at
 546 offset 128KB and the whole image is padded to 4MB which is the SPI flash size.
 547 The position of U-Boot is controlled with this setting in U-Boot:
 548
 549    #define CONFIG_SYS_SPI_U_BOOT_OFFS   (128 << 10)
 550
 551 If you have a Dediprog em100pro connected then you can write the image with:
 552
 553       sudo em100 -s -c GD25LQ32 -d out.bin.pad -r
 554
 555 When booting you should see something like:
 556
 557    U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32)
 558
 559
 560    U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600)
 561
 562    Model: Google Jerry
 563    DRAM:  2 GiB
 564    MMC:
 565    Using default environment
 566
 567    In:    serial@ff690000
 568    Out:   serial@ff690000
 569    Err:   serial@ff690000
 570    =>
 571
 572 Future work
 573 ===========
 574
 575 Immediate priorities are:
 576
 577 - USB host
 578 - USB device
 579 - Run CPU at full speed (code exists but we only see ~60 DMIPS maximum)
 580 - NAND flash
 581 - Boot U-Boot proper over USB OTG (at present only SPL works)
 582
 583
 584 Development Notes
 585 =================
 586
 587 There are plenty of patches in the links below to help with this work.
 588
 589 [1] https://github.com/rkchrome/uboot.git
 590 [2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288
 591 [3] https://github.com/linux-rockchip/rkflashtool.git
 592 [4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en
 593
 594 rkimage
 595 -------
 596
 597 rkimage.c produces an SPL image suitable for sending directly to the boot ROM
 598 over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes)
 599 followed by u-boot-spl-dtb.bin.
 600
 601 The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM
 602 starts at 0xff700000 and extends to 0xff718000 where we put the stack.
 603
 604 rksd
 605 ----
 606
 607 rksd.c produces an image consisting of 32KB of empty space, a header and
 608 u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although
 609 most of the fields are unused by U-Boot. We just need to specify the
 610 signature, a flag and the block offset and size of the SPL image.
 611
 612 The header occupies a single block but we pad it out to 4 blocks. The header
 613 is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL
 614 image can be encoded too but we don't do that.
 615
 616 The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB,
 617 or 0x40 blocks. This is a severe and annoying limitation. There may be a way
 618 around this limitation, since there is plenty of SRAM, but at present the
 619 board refuses to boot if this limit is exceeded.
 620
 621 The image produced is padded up to a block boundary (512 bytes). It should be
 622 written to the start of an SD card using dd.
 623
 624 Since this image is set to load U-Boot from the SD card at block offset,
 625 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write
 626 u-boot-dtb.img to the SD card at that offset. See above for instructions.
 627
 628 rkspi
 629 -----
 630
 631 rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The
 632 resulting image is then spread out so that only the first 2KB of each 4KB
 633 sector is used. The header is the same as with rksd and the maximum size is
 634 also 32KB (before spreading). The image should be written to the start of
 635 SPI flash.
 636
 637 See above for instructions on how to write a SPI image.
 638
 639 rkmux.py
 640 --------
 641
 642 You can use this script to create #defines for SoC register access. See the
 643 script for usage.
 644
 645
 646 Device tree and driver model
 647 ----------------------------
 648
 649 Where possible driver model is used to provide a structure to the
 650 functionality. Device tree is used for configuration. However these have an
 651 overhead and in SPL with a 32KB size limit some shortcuts have been taken.
 652 In general all Rockchip drivers should use these features, with SPL-specific
 653 modifications where required.
 654
 655 GPT partition layout
 656 ----------------------------
 657
 658 Rockchip use a unified GPT partition layout  in open source support.
 659 With this GPT partition layout, uboot can be compatilbe with other components,
 660 like miniloader, trusted-os, arm-trust-firmware.
 661
 662 There are some documents about partitions in the links below.
 663 http://rockchip.wikidot.com/partitions
 664
 665 --
 666 Jagan Teki <jagan@amarulasolutions.com>
 667 27 Mar 2019
 668 Simon Glass <sjg@chromium.org>
 669 24 June 2015