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 8U-Boot on Rockchip 9================== 10 11There are several repositories available with versions of U-Boot that support 12many Rockchip devices [1] [2]. 13 14The current mainline support is experimental only and is not useful for 15anything. It should provide a base on which to build. 16 17So far only support for the RK3288 and RK3036 is provided. 18 19 20Prerequisites 21============= 22 23You 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 36Building 37======== 38 39At 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 50Two RK3036 board are supported: 51 52 - EVB RK3036 - use evb-rk3036 configuration 53 - Kylin - use kylin_rk3036 configuration 54 55For 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 62Writing to the board with USB 63============================= 64 65For USB to work you must get your board into ROM boot mode, either by erasing 66your MMC or (perhaps) holding the recovery button when you boot the board. 67To erase your MMC, you can boot into Linux and type (as root) 68 69 dd if=/dev/zero of=/dev/mmcblk0 bs=1M 70 71Connect your board's OTG port to your computer. 72 73To 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 79If 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 86You will need to reset the board before each time you try. Yes, that's all 87it does so far. If support for the Rockchip USB protocol or DFU were added 88in SPL then we could in principle load U-Boot and boot to a prompt from USB 89as several other platforms do. However it does not seem to be possible to 90use the existing boot ROM code from SPL. 91 92 93Booting from an SD card 94======================= 95 96To 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 103This puts the Rockchip header and SPL image first and then places the U-Boot 104image at block 256 (i.e. 128KB from the start of the SD card). This 105corresponds with this setting in U-Boot: 106 107 #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR 256 108 109Put this SD (or micro-SD) card into your board and reset it. You should see 110something 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 127The rockchip bootrom can load and boot an initial spl, then continue to 128load a second-level bootloader(ie. U-BOOT) as soon as it returns to bootrom. 129Therefore RK3288 has another loading sequence like RK3036. The option of 130U-Boot is controlled with this setting in U-Boot: 131 132 #define CONFIG_ROCKCHIP_SPL_BACK_TO_BROM 133 134You 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 141If you have an HDMI cable attached you should see a video console. 142 143For 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 148Note: rk3036 SDMMC and debug uart use the same iomux, so if you boot from SD, the 149 debug uart must be disabled 150 151 152Booting from an SD card on RK3188 153================================= 154 155For rk3188 boards the general storage onto the card stays the same as 156described above, but the image creation needs a bit more care. 157 158The bootrom of rk3188 expects to find a small 1kb loader which returns 159control to the bootrom, after which it will load the real loader, which 160can then be up to 29kb in size and does the regular ddr init. 161 162Additionally the rk3188 requires everything the bootrom loads to be 163rc4-encrypted. Except for the very first stage the bootrom always reads 164and decodes 2kb pages, so files should be sized accordingly. 165 166# copy tpl, pad to 1020 bytes and append spl 167cat tpl/u-boot-tpl.bin > tplspl.bin 168truncate -s 1020 tplspl.bin 169cat spl/u-boot-spl.bin >> tplspl.bin 170tools/mkimage -n rk3188 -T rksd -d tplspl.bin out 171 172# truncate, encode and append u-boot.bin 173truncate -s %2048 u-boot.bin 174cat u-boot.bin | split -b 512 --filter='openssl rc4 -K 7C4E0304550509072D2C7B38170D1711' >> out 175 176 177Using fastboot on rk3288 178======================== 179- Write GPT partition layout to mmc device which fastboot want to use it to 180store 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 192You 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 202Booting from SPI 203================ 204 205To 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 213This converts the SPL image to the required SPI format by adding the Rockchip 214header and skipping every 2KB block. Then the U-Boot image is written at 215offset 128KB and the whole image is padded to 4MB which is the SPI flash size. 216The position of U-Boot is controlled with this setting in U-Boot: 217 218 #define CONFIG_SYS_SPI_U_BOOT_OFFS (128 << 10) 219 220If 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 224When 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 241Future work 242=========== 243 244Immediate 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 254Development Notes 255================= 256 257There 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 264rkimage 265------- 266 267rkimage.c produces an SPL image suitable for sending directly to the boot ROM 268over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes) 269followed by u-boot-spl-dtb.bin. 270 271The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM 272starts at 0xff700000 and extends to 0xff718000 where we put the stack. 273 274rksd 275---- 276 277rksd.c produces an image consisting of 32KB of empty space, a header and 278u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although 279most of the fields are unused by U-Boot. We just need to specify the 280signature, a flag and the block offset and size of the SPL image. 281 282The header occupies a single block but we pad it out to 4 blocks. The header 283is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL 284image can be encoded too but we don't do that. 285 286The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB, 287or 0x40 blocks. This is a severe and annoying limitation. There may be a way 288around this limitation, since there is plenty of SRAM, but at present the 289board refuses to boot if this limit is exceeded. 290 291The image produced is padded up to a block boundary (512 bytes). It should be 292written to the start of an SD card using dd. 293 294Since this image is set to load U-Boot from the SD card at block offset, 295CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write 296u-boot-dtb.img to the SD card at that offset. See above for instructions. 297 298rkspi 299----- 300 301rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The 302resulting image is then spread out so that only the first 2KB of each 4KB 303sector is used. The header is the same as with rksd and the maximum size is 304also 32KB (before spreading). The image should be written to the start of 305SPI flash. 306 307See above for instructions on how to write a SPI image. 308 309rkmux.py 310-------- 311 312You can use this script to create #defines for SoC register access. See the 313script for usage. 314 315 316Device tree and driver model 317---------------------------- 318 319Where possible driver model is used to provide a structure to the 320functionality. Device tree is used for configuration. However these have an 321overhead and in SPL with a 32KB size limit some shortcuts have been taken. 322In general all Rockchip drivers should use these features, with SPL-specific 323modifications where required. 324 325GPT partition layout 326---------------------------- 327 328Rockchip use a unified GPT partition layout in open source support. 329With this GPT partition layout, uboot can be compatilbe with other components, 330like miniloader, trusted-os, arm-trust-firmware. 331 332There are some documents about partitions in the links below. 333http://rockchip.wikidot.com/partitions 334 335-- 336Simon Glass <sjg@chromium.org> 33724 June 2015 338