doc/README.rockchip

   1 #
   2 # Copyright (C) 2015 Google. Inc
   3 # Written by Simon Glass <sjg@chromium.org>
   4 #
   5 # SPDX-License-Identifier:      GPL-2.0+
   6 #
   7
   8 U-Boot on Rockchip
   9 ==================
  10
  11 There are several repositories available with versions of U-Boot that support
  12 many Rockchip devices [1] [2].
  13
  14 The current mainline support is experimental only and is not useful for
  15 anything. It should provide a base on which to build.
  16
  17 So far only support for the RK3288 and RK3036 is provided.
  18
  19
  20 Prerequisites
  21 =============
  22
  23 You will need:
  24
  25    - Firefly RK3288 board or something else with a supported RockChip SoC
  26    - Power connection to 5V using the supplied micro-USB power cable
  27    - Separate USB serial cable attached to your computer and the Firefly
  28         (connect to the micro-USB connector below the logo)
  29    - rkflashtool [3]
  30    - openssl (sudo apt-get install openssl)
  31    - Serial UART connection [4]
  32    - Suitable ARM cross compiler, e.g.:
  33         sudo apt-get install gcc-4.7-arm-linux-gnueabi
  34
  35
  36 Building
  37 ========
  38
  39 At present eight RK3288 boards are supported:
  40
  41    - EVB RK3288 - use evb-rk3288 configuration
  42    - Fennec RK3288 - use fennec-rk3288 configuration
  43    - Firefly RK3288 - use firefly-rk3288 configuration
  44    - Hisense Chromebook - use chromebook_jerry configuration
  45    - MiQi RK3288 - use miqi-rk3288 configuration
  46    - PopMetal RK3288 - use popmetal-rk3288 configuration
  47    - Radxa Rock 2 - use rock2 configuration
  48    - Tinker RK3288 - use tinker-rk3288 configuration
  49
  50 Two RK3036 board are supported:
  51
  52    - EVB RK3036 - use evb-rk3036 configuration
  53    - Kylin - use kylin_rk3036 configuration
  54
  55 For example:
  56
  57    CROSS_COMPILE=arm-linux-gnueabi- make O=firefly firefly-rk3288_defconfig all
  58
  59 (or you can use another cross compiler if you prefer)
  60
  61
  62 Writing to the board with USB
  63 =============================
  64
  65 For USB to work you must get your board into ROM boot mode, either by erasing
  66 your MMC or (perhaps) holding the recovery button when you boot the board.
  67 To erase your MMC, you can boot into Linux and type (as root)
  68
  69    dd if=/dev/zero of=/dev/mmcblk0 bs=1M
  70
  71 Connect your board's OTG port to your computer.
  72
  73 To create a suitable image and write it to the board:
  74
  75    ./firefly-rk3288/tools/mkimage -n rk3288 -T rkimage -d \
  76         ./firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
  77    cat out | openssl rc4 -K 7c4e0304550509072d2c7b38170d1711 | rkflashtool l
  78
  79 If all goes well you should something like:
  80
  81    U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 10:06:49)
  82    Card did not respond to voltage select!
  83    spl: mmc init failed with error: -17
  84    ### ERROR ### Please RESET the board ###
  85
  86 You will need to reset the board before each time you try. Yes, that's all
  87 it does so far. If support for the Rockchip USB protocol or DFU were added
  88 in SPL then we could in principle load U-Boot and boot to a prompt from USB
  89 as several other platforms do. However it does not seem to be possible to
  90 use the existing boot ROM code from SPL.
  91
  92
  93 Booting from an SD card
  94 =======================
  95
  96 To write an image that boots from an SD card (assumed to be /dev/sdc):
  97
  98    ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \
  99         firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
 100    sudo dd if=out of=/dev/sdc seek=64 && \
 101    sudo dd if=firefly-rk3288/u-boot-dtb.img of=/dev/sdc seek=256
 102
 103 This puts the Rockchip header and SPL image first and then places the U-Boot
 104 image at block 256 (i.e. 128KB from the start of the SD card). This
 105 corresponds with this setting in U-Boot:
 106
 107    #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR      256
 108
 109 Put this SD (or micro-SD) card into your board and reset it. You should see
 110 something like:
 111
 112    U-Boot 2016.01-rc2-00309-ge5bad3b-dirty (Jan 02 2016 - 23:41:59 -0700)
 113
 114    Model: Radxa Rock 2 Square
 115    DRAM:  2 GiB
 116    MMC:   dwmmc@ff0f0000: 0, dwmmc@ff0c0000: 1
 117    *** Warning - bad CRC, using default environment
 118
 119    In:    serial
 120    Out:   vop@ff940000.vidconsole
 121    Err:   serial
 122    Net:   Net Initialization Skipped
 123    No ethernet found.
 124    Hit any key to stop autoboot:  0
 125    =>
 126
 127 The rockchip bootrom can load and boot an initial spl, then continue to
 128 load a second-level bootloader(ie. U-BOOT) as soon as it returns to bootrom.
 129 Therefore RK3288 has another loading sequence like RK3036. The option of
 130 U-Boot is controlled with this setting in U-Boot:
 131
 132         #define CONFIG_ROCKCHIP_SPL_BACK_TO_BROM
 133
 134 You can create the image via the following operations:
 135
 136    ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \
 137         firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
 138    cat firefly-rk3288/u-boot-dtb.bin >> out && \
 139    sudo dd if=out of=/dev/sdc seek=64
 140
 141 If you have an HDMI cable attached you should see a video console.
 142
 143 For evb_rk3036 board:
 144         ./evb-rk3036/tools/mkimage -n rk3036 -T rksd  -d evb-rk3036/spl/u-boot-spl.bin out && \
 145         cat evb-rk3036/u-boot-dtb.bin >> out && \
 146         sudo dd if=out of=/dev/sdc seek=64
 147
 148 Note: rk3036 SDMMC and debug uart use the same iomux, so if you boot from SD, the
 149       debug uart must be disabled
 150
 151
 152 Booting from an SD card on RK3188
 153 =================================
 154
 155 For rk3188 boards the general storage onto the card stays the same as
 156 described above, but the image creation needs a bit more care.
 157
 158 The bootrom of rk3188 expects to find a small 1kb loader which returns
 159 control to the bootrom, after which it will load the real loader, which
 160 can then be up to 29kb in size and does the regular ddr init.
 161
 162 Additionally the rk3188 requires everything the bootrom loads to be
 163 rc4-encrypted. Except for the very first stage the bootrom always reads
 164 and decodes 2kb pages, so files should be sized accordingly.
 165
 166 # copy tpl, pad to 1020 bytes and append spl
 167 cat tpl/u-boot-tpl.bin > tplspl.bin
 168 truncate -s 1020 tplspl.bin
 169 cat spl/u-boot-spl.bin >> tplspl.bin
 170 tools/mkimage -n rk3188 -T rksd -d tplspl.bin out
 171
 172 # truncate, encode and append u-boot.bin
 173 truncate -s %2048 u-boot.bin
 174 cat u-boot.bin | split -b 512 --filter='openssl rc4 -K 7C4E0304550509072D2C7B38170D1711' >> out
 175
 176
 177 Using fastboot on rk3288
 178 ========================
 179 - Write GPT partition layout to mmc device which fastboot want to use it to
 180 store the image
 181
 182         => gpt write mmc 1 $partitions
 183
 184 - Invoke fastboot command to prepare
 185
 186         => fastboot 1
 187
 188 - Start fastboot request on PC
 189
 190         fastboot -i 0x2207 flash loader evb-rk3288/spl/u-boot-spl-dtb.bin
 191
 192 You should see something like:
 193
 194         => fastboot 1
 195         WARNING: unknown variable: partition-type:loader
 196         Starting download of 357796 bytes
 197         ..
 198         downloading of 357796 bytes finished
 199         Flashing Raw Image
 200         ........ wrote 357888 bytes to 'loader'
 201
 202 Booting from SPI
 203 ================
 204
 205 To write an image that boots from SPI flash (e.g. for the Haier Chromebook):
 206
 207    ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \
 208         -d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \
 209    dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \
 210    cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \
 211    dd if=out.bin of=out.bin.pad bs=4M conv=sync
 212
 213 This converts the SPL image to the required SPI format by adding the Rockchip
 214 header and skipping every 2KB block. Then the U-Boot image is written at
 215 offset 128KB and the whole image is padded to 4MB which is the SPI flash size.
 216 The position of U-Boot is controlled with this setting in U-Boot:
 217
 218    #define CONFIG_SYS_SPI_U_BOOT_OFFS   (128 << 10)
 219
 220 If you have a Dediprog em100pro connected then you can write the image with:
 221
 222       sudo em100 -s -c GD25LQ32 -d out.bin.pad -r
 223
 224 When booting you should see something like:
 225
 226    U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32)
 227
 228
 229    U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600)
 230
 231    Model: Google Jerry
 232    DRAM:  2 GiB
 233    MMC:
 234    Using default environment
 235
 236    In:    serial@ff690000
 237    Out:   serial@ff690000
 238    Err:   serial@ff690000
 239    =>
 240
 241 Future work
 242 ===========
 243
 244 Immediate priorities are:
 245
 246 - USB host
 247 - USB device
 248 - Run CPU at full speed (code exists but we only see ~60 DMIPS maximum)
 249 - NAND flash
 250 - Support for other Rockchip parts
 251 - Boot U-Boot proper over USB OTG (at present only SPL works)
 252
 253
 254 Development Notes
 255 =================
 256
 257 There are plenty of patches in the links below to help with this work.
 258
 259 [1] https://github.com/rkchrome/uboot.git
 260 [2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288
 261 [3] https://github.com/linux-rockchip/rkflashtool.git
 262 [4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en
 263
 264 rkimage
 265 -------
 266
 267 rkimage.c produces an SPL image suitable for sending directly to the boot ROM
 268 over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes)
 269 followed by u-boot-spl-dtb.bin.
 270
 271 The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM
 272 starts at 0xff700000 and extends to 0xff718000 where we put the stack.
 273
 274 rksd
 275 ----
 276
 277 rksd.c produces an image consisting of 32KB of empty space, a header and
 278 u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although
 279 most of the fields are unused by U-Boot. We just need to specify the
 280 signature, a flag and the block offset and size of the SPL image.
 281
 282 The header occupies a single block but we pad it out to 4 blocks. The header
 283 is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL
 284 image can be encoded too but we don't do that.
 285
 286 The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB,
 287 or 0x40 blocks. This is a severe and annoying limitation. There may be a way
 288 around this limitation, since there is plenty of SRAM, but at present the
 289 board refuses to boot if this limit is exceeded.
 290
 291 The image produced is padded up to a block boundary (512 bytes). It should be
 292 written to the start of an SD card using dd.
 293
 294 Since this image is set to load U-Boot from the SD card at block offset,
 295 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write
 296 u-boot-dtb.img to the SD card at that offset. See above for instructions.
 297
 298 rkspi
 299 -----
 300
 301 rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The
 302 resulting image is then spread out so that only the first 2KB of each 4KB
 303 sector is used. The header is the same as with rksd and the maximum size is
 304 also 32KB (before spreading). The image should be written to the start of
 305 SPI flash.
 306
 307 See above for instructions on how to write a SPI image.
 308
 309 rkmux.py
 310 --------
 311
 312 You can use this script to create #defines for SoC register access. See the
 313 script for usage.
 314
 315
 316 Device tree and driver model
 317 ----------------------------
 318
 319 Where possible driver model is used to provide a structure to the
 320 functionality. Device tree is used for configuration. However these have an
 321 overhead and in SPL with a 32KB size limit some shortcuts have been taken.
 322 In general all Rockchip drivers should use these features, with SPL-specific
 323 modifications where required.
 324
 325 GPT partition layout
 326 ----------------------------
 327
 328 Rockchip use a unified GPT partition layout  in open source support.
 329 With this GPT partition layout, uboot can be compatilbe with other components,
 330 like miniloader, trusted-os, arm-trust-firmware.
 331
 332 There are some documents about partitions in the links below.
 333 http://rockchip.wikidot.com/partitions
 334
 335 --
 336 Simon Glass <sjg@chromium.org>
 337 24 June 2015