1# SPDX-License-Identifier: GPL-2.0+ 2# 3# Copyright (C) 2015 Google. Inc 4# Written by Simon Glass <sjg@chromium.org> 5 6U-Boot on Rockchip 7================== 8 9There are several repositories available with versions of U-Boot that support 10many Rockchip devices [1] [2]. 11 12The current mainline support is experimental only and is not useful for 13anything. It should provide a base on which to build. 14 15So far only support for the RK3288 and RK3036 is provided. 16 17 18Prerequisites 19============= 20 21You will need: 22 23 - Firefly RK3288 board or something else with a supported RockChip SoC 24 - Power connection to 5V using the supplied micro-USB power cable 25 - Separate USB serial cable attached to your computer and the Firefly 26 (connect to the micro-USB connector below the logo) 27 - rkflashtool [3] 28 - openssl (sudo apt-get install openssl) 29 - Serial UART connection [4] 30 - Suitable ARM cross compiler, e.g.: 31 sudo apt-get install gcc-4.7-arm-linux-gnueabi 32 33 34Building 35======== 36 37At present nine RK3288 boards are supported: 38 39 - EVB RK3288 - use evb-rk3288 configuration 40 - Fennec RK3288 - use fennec-rk3288 configuration 41 - Firefly RK3288 - use firefly-rk3288 configuration 42 - Hisense Chromebook - use chromebook_jerry configuration 43 - MiQi RK3288 - use miqi-rk3288 configuration 44 - phyCORE-RK3288 RDK - use phycore-rk3288 configuration 45 - PopMetal RK3288 - use popmetal-rk3288 configuration 46 - Radxa Rock 2 - use rock2 configuration 47 - Tinker RK3288 - use tinker-rk3288 configuration 48 49Two RK3036 board are supported: 50 51 - EVB RK3036 - use evb-rk3036 configuration 52 - Kylin - use kylin_rk3036 configuration 53 54For example: 55 56 CROSS_COMPILE=arm-linux-gnueabi- make O=firefly firefly-rk3288_defconfig all 57 58(or you can use another cross compiler if you prefer) 59 60 61Writing to the board with USB 62============================= 63 64For USB to work you must get your board into ROM boot mode, either by erasing 65your MMC or (perhaps) holding the recovery button when you boot the board. 66To erase your MMC, you can boot into Linux and type (as root) 67 68 dd if=/dev/zero of=/dev/mmcblk0 bs=1M 69 70Connect your board's OTG port to your computer. 71 72To create a suitable image and write it to the board: 73 74 ./firefly-rk3288/tools/mkimage -n rk3288 -T rkimage -d \ 75 ./firefly-rk3288/spl/u-boot-spl-dtb.bin out && \ 76 cat out | openssl rc4 -K 7c4e0304550509072d2c7b38170d1711 | rkflashtool l 77 78If all goes well you should something like: 79 80 U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 10:06:49) 81 Card did not respond to voltage select! 82 spl: mmc init failed with error: -17 83 ### ERROR ### Please RESET the board ### 84 85You will need to reset the board before each time you try. Yes, that's all 86it does so far. If support for the Rockchip USB protocol or DFU were added 87in SPL then we could in principle load U-Boot and boot to a prompt from USB 88as several other platforms do. However it does not seem to be possible to 89use the existing boot ROM code from SPL. 90 91 92Booting from an SD card 93======================= 94 95To write an image that boots from an SD card (assumed to be /dev/sdc): 96 97 ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \ 98 firefly-rk3288/spl/u-boot-spl-dtb.bin out && \ 99 sudo dd if=out of=/dev/sdc seek=64 && \ 100 sudo dd if=firefly-rk3288/u-boot-dtb.img of=/dev/sdc seek=16384 101 102This puts the Rockchip header and SPL image first and then places the U-Boot 103image at block 16384 (i.e. 8MB from the start of the SD card). This 104corresponds with this setting in U-Boot: 105 106 #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR 0x4000 107 108Put this SD (or micro-SD) card into your board and reset it. You should see 109something like: 110 111 U-Boot 2016.01-rc2-00309-ge5bad3b-dirty (Jan 02 2016 - 23:41:59 -0700) 112 113 Model: Radxa Rock 2 Square 114 DRAM: 2 GiB 115 MMC: dwmmc@ff0f0000: 0, dwmmc@ff0c0000: 1 116 *** Warning - bad CRC, using default environment 117 118 In: serial 119 Out: vop@ff940000.vidconsole 120 Err: serial 121 Net: Net Initialization Skipped 122 No ethernet found. 123 Hit any key to stop autoboot: 0 124 => 125 126The rockchip bootrom can load and boot an initial spl, then continue to 127load a second-stage bootloader (ie. U-Boot) as soon as the control is returned 128to the bootrom. Both the RK3288 and the RK3036 use this special boot sequence. 129The configuration option enabling this is: 130 131 CONFIG_SPL_ROCKCHIP_BACK_TO_BROM=y 132 133You can create the image via the following operations: 134 135 ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \ 136 firefly-rk3288/spl/u-boot-spl-dtb.bin out && \ 137 cat firefly-rk3288/u-boot-dtb.bin >> out && \ 138 sudo dd if=out of=/dev/sdc seek=64 139 140If you have an HDMI cable attached you should see a video console. 141 142For evb_rk3036 board: 143 ./evb-rk3036/tools/mkimage -n rk3036 -T rksd -d evb-rk3036/spl/u-boot-spl.bin out && \ 144 cat evb-rk3036/u-boot-dtb.bin >> out && \ 145 sudo dd if=out of=/dev/sdc seek=64 146 147Note: rk3036 SDMMC and debug uart use the same iomux, so if you boot from SD, the 148 debug uart must be disabled 149 150 151Booting from an SD card on RK3288 with TPL 152========================================== 153 154Since the size of SPL can't be exceeded 0x8000 bytes in RK3288, it is not possible add 155new SPL features like Falcon mode or etc. 156 157So introduce TPL so-that adding new features to SPL is possible because now TPL should 158run minimal with code like DDR, clock etc and rest of new features in SPL. 159 160As of now TPL is added on Vyasa-RK3288 board. 161 162To write an image that boots from an SD card (assumed to be /dev/mmcblk0): 163 164 ./tools/mkimage -n rk3288 -T rksd -d ./tpl/u-boot-tpl.bin out && 165 cat ./spl/u-boot-spl-dtb.bin >> out && 166 sudo dd if=out of=/dev/mmcblk0 seek=64 && 167 sudo dd if=u-boot-dtb.img of=/dev/mmcblk0 seek=16384 168 169Booting from an SD card on RK3188 170================================= 171 172For rk3188 boards the general storage onto the card stays the same as 173described above, but the image creation needs a bit more care. 174 175The bootrom of rk3188 expects to find a small 1kb loader which returns 176control to the bootrom, after which it will load the real loader, which 177can then be up to 29kb in size and does the regular ddr init. This is 178handled by a single image (built as the SPL stage) that tests whether 179it is handled for the first or second time via code executed from the 180boot0-hook. 181 182Additionally the rk3188 requires everything the bootrom loads to be 183rc4-encrypted. Except for the very first stage the bootrom always reads 184and decodes 2kb pages, so files should be sized accordingly. 185 186# copy tpl, pad to 1020 bytes and append spl 187tools/mkimage -n rk3188 -T rksd -d spl/u-boot-spl.bin out 188 189# truncate, encode and append u-boot.bin 190truncate -s %2048 u-boot.bin 191cat u-boot.bin | split -b 512 --filter='openssl rc4 -K 7C4E0304550509072D2C7B38170D1711' >> out 192 193 194Using fastboot on rk3288 195======================== 196- Write GPT partition layout to mmc device which fastboot want to use it to 197store the image 198 199 => gpt write mmc 1 $partitions 200 201- Invoke fastboot command to prepare 202 203 => fastboot 1 204 205- Start fastboot request on PC 206 207 fastboot -i 0x2207 flash loader evb-rk3288/spl/u-boot-spl-dtb.bin 208 209You should see something like: 210 211 => fastboot 1 212 WARNING: unknown variable: partition-type:loader 213 Starting download of 357796 bytes 214 .. 215 downloading of 357796 bytes finished 216 Flashing Raw Image 217 ........ wrote 357888 bytes to 'loader' 218 219Booting from SPI 220================ 221 222To write an image that boots from SPI flash (e.g. for the Haier Chromebook): 223 224 ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \ 225 -d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \ 226 dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \ 227 cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \ 228 dd if=out.bin of=out.bin.pad bs=4M conv=sync 229 230This converts the SPL image to the required SPI format by adding the Rockchip 231header and skipping every 2KB block. Then the U-Boot image is written at 232offset 128KB and the whole image is padded to 4MB which is the SPI flash size. 233The position of U-Boot is controlled with this setting in U-Boot: 234 235 #define CONFIG_SYS_SPI_U_BOOT_OFFS (128 << 10) 236 237If you have a Dediprog em100pro connected then you can write the image with: 238 239 sudo em100 -s -c GD25LQ32 -d out.bin.pad -r 240 241When booting you should see something like: 242 243 U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32) 244 245 246 U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600) 247 248 Model: Google Jerry 249 DRAM: 2 GiB 250 MMC: 251 Using default environment 252 253 In: serial@ff690000 254 Out: serial@ff690000 255 Err: serial@ff690000 256 => 257 258Future work 259=========== 260 261Immediate priorities are: 262 263- USB host 264- USB device 265- Run CPU at full speed (code exists but we only see ~60 DMIPS maximum) 266- NAND flash 267- Support for other Rockchip parts 268- Boot U-Boot proper over USB OTG (at present only SPL works) 269 270 271Development Notes 272================= 273 274There are plenty of patches in the links below to help with this work. 275 276[1] https://github.com/rkchrome/uboot.git 277[2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288 278[3] https://github.com/linux-rockchip/rkflashtool.git 279[4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en 280 281rkimage 282------- 283 284rkimage.c produces an SPL image suitable for sending directly to the boot ROM 285over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes) 286followed by u-boot-spl-dtb.bin. 287 288The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM 289starts at 0xff700000 and extends to 0xff718000 where we put the stack. 290 291rksd 292---- 293 294rksd.c produces an image consisting of 32KB of empty space, a header and 295u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although 296most of the fields are unused by U-Boot. We just need to specify the 297signature, a flag and the block offset and size of the SPL image. 298 299The header occupies a single block but we pad it out to 4 blocks. The header 300is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL 301image can be encoded too but we don't do that. 302 303The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB, 304or 0x40 blocks. This is a severe and annoying limitation. There may be a way 305around this limitation, since there is plenty of SRAM, but at present the 306board refuses to boot if this limit is exceeded. 307 308The image produced is padded up to a block boundary (512 bytes). It should be 309written to the start of an SD card using dd. 310 311Since this image is set to load U-Boot from the SD card at block offset, 312CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write 313u-boot-dtb.img to the SD card at that offset. See above for instructions. 314 315rkspi 316----- 317 318rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The 319resulting image is then spread out so that only the first 2KB of each 4KB 320sector is used. The header is the same as with rksd and the maximum size is 321also 32KB (before spreading). The image should be written to the start of 322SPI flash. 323 324See above for instructions on how to write a SPI image. 325 326rkmux.py 327-------- 328 329You can use this script to create #defines for SoC register access. See the 330script for usage. 331 332 333Device tree and driver model 334---------------------------- 335 336Where possible driver model is used to provide a structure to the 337functionality. Device tree is used for configuration. However these have an 338overhead and in SPL with a 32KB size limit some shortcuts have been taken. 339In general all Rockchip drivers should use these features, with SPL-specific 340modifications where required. 341 342GPT partition layout 343---------------------------- 344 345Rockchip use a unified GPT partition layout in open source support. 346With this GPT partition layout, uboot can be compatilbe with other components, 347like miniloader, trusted-os, arm-trust-firmware. 348 349There are some documents about partitions in the links below. 350http://rockchip.wikidot.com/partitions 351 352-- 353Simon Glass <sjg@chromium.org> 35424 June 2015 355