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 nine 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 - phyCORE-RK3288 RDK - use phycore-rk3288 configuration 47 - PopMetal RK3288 - use popmetal-rk3288 configuration 48 - Radxa Rock 2 - use rock2 configuration 49 - Tinker RK3288 - use tinker-rk3288 configuration 50 51Two RK3036 board are supported: 52 53 - EVB RK3036 - use evb-rk3036 configuration 54 - Kylin - use kylin_rk3036 configuration 55 56For example: 57 58 CROSS_COMPILE=arm-linux-gnueabi- make O=firefly firefly-rk3288_defconfig all 59 60(or you can use another cross compiler if you prefer) 61 62 63Writing to the board with USB 64============================= 65 66For USB to work you must get your board into ROM boot mode, either by erasing 67your MMC or (perhaps) holding the recovery button when you boot the board. 68To erase your MMC, you can boot into Linux and type (as root) 69 70 dd if=/dev/zero of=/dev/mmcblk0 bs=1M 71 72Connect your board's OTG port to your computer. 73 74To create a suitable image and write it to the board: 75 76 ./firefly-rk3288/tools/mkimage -n rk3288 -T rkimage -d \ 77 ./firefly-rk3288/spl/u-boot-spl-dtb.bin out && \ 78 cat out | openssl rc4 -K 7c4e0304550509072d2c7b38170d1711 | rkflashtool l 79 80If all goes well you should something like: 81 82 U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 10:06:49) 83 Card did not respond to voltage select! 84 spl: mmc init failed with error: -17 85 ### ERROR ### Please RESET the board ### 86 87You will need to reset the board before each time you try. Yes, that's all 88it does so far. If support for the Rockchip USB protocol or DFU were added 89in SPL then we could in principle load U-Boot and boot to a prompt from USB 90as several other platforms do. However it does not seem to be possible to 91use the existing boot ROM code from SPL. 92 93 94Booting from an SD card 95======================= 96 97To write an image that boots from an SD card (assumed to be /dev/sdc): 98 99 ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \ 100 firefly-rk3288/spl/u-boot-spl-dtb.bin out && \ 101 sudo dd if=out of=/dev/sdc seek=64 && \ 102 sudo dd if=firefly-rk3288/u-boot-dtb.img of=/dev/sdc seek=16384 103 104This puts the Rockchip header and SPL image first and then places the U-Boot 105image at block 16384 (i.e. 8MB from the start of the SD card). This 106corresponds with this setting in U-Boot: 107 108 #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR 0x4000 109 110Put this SD (or micro-SD) card into your board and reset it. You should see 111something like: 112 113 U-Boot 2016.01-rc2-00309-ge5bad3b-dirty (Jan 02 2016 - 23:41:59 -0700) 114 115 Model: Radxa Rock 2 Square 116 DRAM: 2 GiB 117 MMC: dwmmc@ff0f0000: 0, dwmmc@ff0c0000: 1 118 *** Warning - bad CRC, using default environment 119 120 In: serial 121 Out: vop@ff940000.vidconsole 122 Err: serial 123 Net: Net Initialization Skipped 124 No ethernet found. 125 Hit any key to stop autoboot: 0 126 => 127 128The rockchip bootrom can load and boot an initial spl, then continue to 129load a second-level bootloader(ie. U-BOOT) as soon as it returns to bootrom. 130Therefore RK3288 has another loading sequence like RK3036. The option of 131U-Boot is controlled with this setting in U-Boot: 132 133 #define CONFIG_SPL_ROCKCHIP_BACK_TO_BROM 134 135You can create the image via the following operations: 136 137 ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \ 138 firefly-rk3288/spl/u-boot-spl-dtb.bin out && \ 139 cat firefly-rk3288/u-boot-dtb.bin >> out && \ 140 sudo dd if=out of=/dev/sdc seek=64 141 142If you have an HDMI cable attached you should see a video console. 143 144For evb_rk3036 board: 145 ./evb-rk3036/tools/mkimage -n rk3036 -T rksd -d evb-rk3036/spl/u-boot-spl.bin out && \ 146 cat evb-rk3036/u-boot-dtb.bin >> out && \ 147 sudo dd if=out of=/dev/sdc seek=64 148 149Note: rk3036 SDMMC and debug uart use the same iomux, so if you boot from SD, the 150 debug uart must be disabled 151 152 153Booting from an SD card on RK3288 with TPL 154========================================== 155 156Since the size of SPL can't be exceeded 0x8000 bytes in RK3288, it is not possible add 157new SPL features like Falcon mode or etc. 158 159So introduce TPL so-that adding new features to SPL is possible because now TPL should 160run minimal with code like DDR, clock etc and rest of new features in SPL. 161 162As of now TPL is added on Vyasa-RK3288 board. 163 164To write an image that boots from an SD card (assumed to be /dev/mmcblk0): 165 166 ./tools/mkimage -n rk3288 -T rksd -d ./tpl/u-boot-tpl.bin out && 167 cat ./spl/u-boot-spl-dtb.bin >> out && 168 sudo dd if=out of=/dev/mmcblk0 seek=64 && 169 sudo dd if=u-boot-dtb.img of=/dev/mmcblk0 seek=16384 170 171Booting from an SD card on RK3188 172================================= 173 174For rk3188 boards the general storage onto the card stays the same as 175described above, but the image creation needs a bit more care. 176 177The bootrom of rk3188 expects to find a small 1kb loader which returns 178control to the bootrom, after which it will load the real loader, which 179can then be up to 29kb in size and does the regular ddr init. This is 180handled by a single image (built as the SPL stage) that tests whether 181it is handled for the first or second time via code executed from the 182boot0-hook. 183 184Additionally the rk3188 requires everything the bootrom loads to be 185rc4-encrypted. Except for the very first stage the bootrom always reads 186and decodes 2kb pages, so files should be sized accordingly. 187 188# copy tpl, pad to 1020 bytes and append spl 189tools/mkimage -n rk3188 -T rksd -d spl/u-boot-spl.bin out 190 191# truncate, encode and append u-boot.bin 192truncate -s %2048 u-boot.bin 193cat u-boot.bin | split -b 512 --filter='openssl rc4 -K 7C4E0304550509072D2C7B38170D1711' >> out 194 195 196Using fastboot on rk3288 197======================== 198- Write GPT partition layout to mmc device which fastboot want to use it to 199store the image 200 201 => gpt write mmc 1 $partitions 202 203- Invoke fastboot command to prepare 204 205 => fastboot 1 206 207- Start fastboot request on PC 208 209 fastboot -i 0x2207 flash loader evb-rk3288/spl/u-boot-spl-dtb.bin 210 211You should see something like: 212 213 => fastboot 1 214 WARNING: unknown variable: partition-type:loader 215 Starting download of 357796 bytes 216 .. 217 downloading of 357796 bytes finished 218 Flashing Raw Image 219 ........ wrote 357888 bytes to 'loader' 220 221Booting from SPI 222================ 223 224To write an image that boots from SPI flash (e.g. for the Haier Chromebook): 225 226 ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \ 227 -d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \ 228 dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \ 229 cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \ 230 dd if=out.bin of=out.bin.pad bs=4M conv=sync 231 232This converts the SPL image to the required SPI format by adding the Rockchip 233header and skipping every 2KB block. Then the U-Boot image is written at 234offset 128KB and the whole image is padded to 4MB which is the SPI flash size. 235The position of U-Boot is controlled with this setting in U-Boot: 236 237 #define CONFIG_SYS_SPI_U_BOOT_OFFS (128 << 10) 238 239If you have a Dediprog em100pro connected then you can write the image with: 240 241 sudo em100 -s -c GD25LQ32 -d out.bin.pad -r 242 243When booting you should see something like: 244 245 U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32) 246 247 248 U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600) 249 250 Model: Google Jerry 251 DRAM: 2 GiB 252 MMC: 253 Using default environment 254 255 In: serial@ff690000 256 Out: serial@ff690000 257 Err: serial@ff690000 258 => 259 260Future work 261=========== 262 263Immediate priorities are: 264 265- USB host 266- USB device 267- Run CPU at full speed (code exists but we only see ~60 DMIPS maximum) 268- NAND flash 269- Support for other Rockchip parts 270- Boot U-Boot proper over USB OTG (at present only SPL works) 271 272 273Development Notes 274================= 275 276There are plenty of patches in the links below to help with this work. 277 278[1] https://github.com/rkchrome/uboot.git 279[2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288 280[3] https://github.com/linux-rockchip/rkflashtool.git 281[4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en 282 283rkimage 284------- 285 286rkimage.c produces an SPL image suitable for sending directly to the boot ROM 287over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes) 288followed by u-boot-spl-dtb.bin. 289 290The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM 291starts at 0xff700000 and extends to 0xff718000 where we put the stack. 292 293rksd 294---- 295 296rksd.c produces an image consisting of 32KB of empty space, a header and 297u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although 298most of the fields are unused by U-Boot. We just need to specify the 299signature, a flag and the block offset and size of the SPL image. 300 301The header occupies a single block but we pad it out to 4 blocks. The header 302is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL 303image can be encoded too but we don't do that. 304 305The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB, 306or 0x40 blocks. This is a severe and annoying limitation. There may be a way 307around this limitation, since there is plenty of SRAM, but at present the 308board refuses to boot if this limit is exceeded. 309 310The image produced is padded up to a block boundary (512 bytes). It should be 311written to the start of an SD card using dd. 312 313Since this image is set to load U-Boot from the SD card at block offset, 314CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write 315u-boot-dtb.img to the SD card at that offset. See above for instructions. 316 317rkspi 318----- 319 320rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The 321resulting image is then spread out so that only the first 2KB of each 4KB 322sector is used. The header is the same as with rksd and the maximum size is 323also 32KB (before spreading). The image should be written to the start of 324SPI flash. 325 326See above for instructions on how to write a SPI image. 327 328rkmux.py 329-------- 330 331You can use this script to create #defines for SoC register access. See the 332script for usage. 333 334 335Device tree and driver model 336---------------------------- 337 338Where possible driver model is used to provide a structure to the 339functionality. Device tree is used for configuration. However these have an 340overhead and in SPL with a 32KB size limit some shortcuts have been taken. 341In general all Rockchip drivers should use these features, with SPL-specific 342modifications where required. 343 344GPT partition layout 345---------------------------- 346 347Rockchip use a unified GPT partition layout in open source support. 348With this GPT partition layout, uboot can be compatilbe with other components, 349like miniloader, trusted-os, arm-trust-firmware. 350 351There are some documents about partitions in the links below. 352http://rockchip.wikidot.com/partitions 353 354-- 355Simon Glass <sjg@chromium.org> 35624 June 2015 357