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 three RK3288 boards are supported:
  40
  41    - Firefly RK3288 - use firefly-rk3288 configuration
  42    - Radxa Rock 2 - use rock2 configuration
  43    - Hisense Chromebook - use chromebook_jerry configuration
  44
  45 Two RK3036 board are supported:
  46
  47    - EVB RK3036 - use evb-rk3036 configuration
  48    - Kylin - use kylin_rk3036 configuration
  49
  50 For example:
  51
  52    CROSS_COMPILE=arm-linux-gnueabi- make O=firefly firefly-rk3288_defconfig all
  53
  54 (or you can use another cross compiler if you prefer)
  55
  56
  57 Writing to the board with USB
  58 =============================
  59
  60 For USB to work you must get your board into ROM boot mode, either by erasing
  61 your MMC or (perhaps) holding the recovery button when you boot the board.
  62 To erase your MMC, you can boot into Linux and type (as root)
  63
  64    dd if=/dev/zero of=/dev/mmcblk0 bs=1M
  65
  66 Connect your board's OTG port to your computer.
  67
  68 To create a suitable image and write it to the board:
  69
  70    ./firefly-rk3288/tools/mkimage -n rk3288 -T rkimage -d \
  71         ./firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
  72    cat out | openssl rc4 -K 7c4e0304550509072d2c7b38170d1711 | rkflashtool l
  73
  74 If all goes well you should something like:
  75
  76    U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 10:06:49)
  77    Card did not respond to voltage select!
  78    spl: mmc init failed with error: -17
  79    ### ERROR ### Please RESET the board ###
  80
  81 You will need to reset the board before each time you try. Yes, that's all
  82 it does so far. If support for the Rockchip USB protocol or DFU were added
  83 in SPL then we could in principle load U-Boot and boot to a prompt from USB
  84 as several other platforms do. However it does not seem to be possible to
  85 use the existing boot ROM code from SPL.
  86
  87
  88 Booting from an SD card
  89 =======================
  90
  91 To write an image that boots from an SD card (assumed to be /dev/sdc):
  92
  93    ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \
  94         firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
  95    sudo dd if=out of=/dev/sdc seek=64 && \
  96    sudo dd if=firefly-rk3288/u-boot-dtb.img of=/dev/sdc seek=256
  97
  98 This puts the Rockchip header and SPL image first and then places the U-Boot
  99 image at block 256 (i.e. 128KB from the start of the SD card). This
 100 corresponds with this setting in U-Boot:
 101
 102    #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR      256
 103
 104 Put this SD (or micro-SD) card into your board and reset it. You should see
 105 something like:
 106
 107    U-Boot 2016.01-rc2-00309-ge5bad3b-dirty (Jan 02 2016 - 23:41:59 -0700)
 108
 109    Model: Radxa Rock 2 Square
 110    DRAM:  2 GiB
 111    MMC:   dwmmc@ff0f0000: 0, dwmmc@ff0c0000: 1
 112    *** Warning - bad CRC, using default environment
 113
 114    In:    serial
 115    Out:   vop@ff940000.vidconsole
 116    Err:   serial
 117    Net:   Net Initialization Skipped
 118    No ethernet found.
 119    Hit any key to stop autoboot:  0
 120    =>
 121
 122 If you have an HDMI cable attached you should see a video console.
 123
 124 For evb_rk3036 board:
 125         ./evb-rk3036/tools/mkimage -n rk3036 -T rksd  -d evb-rk3036/spl/u-boot-spl.bin out && \
 126         cat evb-rk3036/u-boot-dtb.bin >> out && \
 127         sudo dd if=out of=/dev/sdc seek=64
 128
 129 Note: rk3036 SDMMC and debug uart use the same iomux, so if you boot from SD, the
 130       debug uart must be disabled
 131
 132 Booting from SPI
 133 ================
 134
 135 To write an image that boots from SPI flash (e.g. for the Haier Chromebook):
 136
 137    ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \
 138         -d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \
 139    dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \
 140    cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \
 141    dd if=out.bin of=out.bin.pad bs=4M conv=sync
 142
 143 This converts the SPL image to the required SPI format by adding the Rockchip
 144 header and skipping every 2KB block. Then the U-Boot image is written at
 145 offset 128KB and the whole image is padded to 4MB which is the SPI flash size.
 146 The position of U-Boot is controlled with this setting in U-Boot:
 147
 148    #define CONFIG_SYS_SPI_U_BOOT_OFFS   (128 << 10)
 149
 150 If you have a Dediprog em100pro connected then you can write the image with:
 151
 152       sudo em100 -s -c GD25LQ32 -d out.bin.pad -r
 153
 154 When booting you should see something like:
 155
 156    U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32)
 157
 158
 159    U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600)
 160
 161    Model: Google Jerry
 162    DRAM:  2 GiB
 163    MMC:
 164    Using default environment
 165
 166    In:    serial@ff690000
 167    Out:   serial@ff690000
 168    Err:   serial@ff690000
 169    =>
 170
 171
 172 Future work
 173 ===========
 174
 175 Immediate priorities are:
 176
 177 - USB host
 178 - USB device
 179 - Run CPU at full speed (code exists but we only see ~60 DMIPS maximum)
 180 - Ethernet
 181 - NAND flash
 182 - Support for other Rockchip parts
 183 - Boot U-Boot proper over USB OTG (at present only SPL works)
 184
 185
 186 Development Notes
 187 =================
 188
 189 There are plenty of patches in the links below to help with this work.
 190
 191 [1] https://github.com/rkchrome/uboot.git
 192 [2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288
 193 [3] https://github.com/linux-rockchip/rkflashtool.git
 194 [4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en
 195
 196 rkimage
 197 -------
 198
 199 rkimage.c produces an SPL image suitable for sending directly to the boot ROM
 200 over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes)
 201 followed by u-boot-spl-dtb.bin.
 202
 203 The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM
 204 starts at 0xff700000 and extends to 0xff718000 where we put the stack.
 205
 206 rksd
 207 ----
 208
 209 rksd.c produces an image consisting of 32KB of empty space, a header and
 210 u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although
 211 most of the fields are unused by U-Boot. We just need to specify the
 212 signature, a flag and the block offset and size of the SPL image.
 213
 214 The header occupies a single block but we pad it out to 4 blocks. The header
 215 is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL
 216 image can be encoded too but we don't do that.
 217
 218 The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB,
 219 or 0x40 blocks. This is a severe and annoying limitation. There may be a way
 220 around this limitation, since there is plenty of SRAM, but at present the
 221 board refuses to boot if this limit is exceeded.
 222
 223 The image produced is padded up to a block boundary (512 bytes). It should be
 224 written to the start of an SD card using dd.
 225
 226 Since this image is set to load U-Boot from the SD card at block offset,
 227 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write
 228 u-boot-dtb.img to the SD card at that offset. See above for instructions.
 229
 230 rkspi
 231 -----
 232
 233 rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The
 234 resulting image is then spread out so that only the first 2KB of each 4KB
 235 sector is used. The header is the same as with rksd and the maximum size is
 236 also 32KB (before spreading). The image should be written to the start of
 237 SPI flash.
 238
 239 See above for instructions on how to write a SPI image.
 240
 241 rkmux.py
 242 --------
 243
 244 You can use this script to create #defines for SoC register access. See the
 245 script for usage.
 246
 247
 248 Device tree and driver model
 249 ----------------------------
 250
 251 Where possible driver model is used to provide a structure to the
 252 functionality. Device tree is used for configuration. However these have an
 253 overhead and in SPL with a 32KB size limit some shortcuts have been taken.
 254 In general all Rockchip drivers should use these features, with SPL-specific
 255 modifications where required.
 256
 257
 258 --
 259 Simon Glass <sjg@chromium.org>
 260 24 June 2015