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=256 103 104This puts the Rockchip header and SPL image first and then places the U-Boot 105image at block 256 (i.e. 128KB 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 256 109 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_ROCKCHIP_SPL_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 RK3188 154================================= 155 156For rk3188 boards the general storage onto the card stays the same as 157described above, but the image creation needs a bit more care. 158 159The bootrom of rk3188 expects to find a small 1kb loader which returns 160control to the bootrom, after which it will load the real loader, which 161can then be up to 29kb in size and does the regular ddr init. 162 163Additionally the rk3188 requires everything the bootrom loads to be 164rc4-encrypted. Except for the very first stage the bootrom always reads 165and decodes 2kb pages, so files should be sized accordingly. 166 167# copy tpl, pad to 1020 bytes and append spl 168cat tpl/u-boot-tpl.bin > tplspl.bin 169truncate -s 1020 tplspl.bin 170cat spl/u-boot-spl.bin >> tplspl.bin 171tools/mkimage -n rk3188 -T rksd -d tplspl.bin out 172 173# truncate, encode and append u-boot.bin 174truncate -s %2048 u-boot.bin 175cat u-boot.bin | split -b 512 --filter='openssl rc4 -K 7C4E0304550509072D2C7B38170D1711' >> out 176 177 178Using fastboot on rk3288 179======================== 180- Write GPT partition layout to mmc device which fastboot want to use it to 181store the image 182 183 => gpt write mmc 1 $partitions 184 185- Invoke fastboot command to prepare 186 187 => fastboot 1 188 189- Start fastboot request on PC 190 191 fastboot -i 0x2207 flash loader evb-rk3288/spl/u-boot-spl-dtb.bin 192 193You should see something like: 194 195 => fastboot 1 196 WARNING: unknown variable: partition-type:loader 197 Starting download of 357796 bytes 198 .. 199 downloading of 357796 bytes finished 200 Flashing Raw Image 201 ........ wrote 357888 bytes to 'loader' 202 203Booting from SPI 204================ 205 206To write an image that boots from SPI flash (e.g. for the Haier Chromebook): 207 208 ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \ 209 -d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \ 210 dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \ 211 cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \ 212 dd if=out.bin of=out.bin.pad bs=4M conv=sync 213 214This converts the SPL image to the required SPI format by adding the Rockchip 215header and skipping every 2KB block. Then the U-Boot image is written at 216offset 128KB and the whole image is padded to 4MB which is the SPI flash size. 217The position of U-Boot is controlled with this setting in U-Boot: 218 219 #define CONFIG_SYS_SPI_U_BOOT_OFFS (128 << 10) 220 221If you have a Dediprog em100pro connected then you can write the image with: 222 223 sudo em100 -s -c GD25LQ32 -d out.bin.pad -r 224 225When booting you should see something like: 226 227 U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32) 228 229 230 U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600) 231 232 Model: Google Jerry 233 DRAM: 2 GiB 234 MMC: 235 Using default environment 236 237 In: serial@ff690000 238 Out: serial@ff690000 239 Err: serial@ff690000 240 => 241 242Future work 243=========== 244 245Immediate priorities are: 246 247- USB host 248- USB device 249- Run CPU at full speed (code exists but we only see ~60 DMIPS maximum) 250- NAND flash 251- Support for other Rockchip parts 252- Boot U-Boot proper over USB OTG (at present only SPL works) 253 254 255Development Notes 256================= 257 258There are plenty of patches in the links below to help with this work. 259 260[1] https://github.com/rkchrome/uboot.git 261[2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288 262[3] https://github.com/linux-rockchip/rkflashtool.git 263[4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en 264 265rkimage 266------- 267 268rkimage.c produces an SPL image suitable for sending directly to the boot ROM 269over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes) 270followed by u-boot-spl-dtb.bin. 271 272The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM 273starts at 0xff700000 and extends to 0xff718000 where we put the stack. 274 275rksd 276---- 277 278rksd.c produces an image consisting of 32KB of empty space, a header and 279u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although 280most of the fields are unused by U-Boot. We just need to specify the 281signature, a flag and the block offset and size of the SPL image. 282 283The header occupies a single block but we pad it out to 4 blocks. The header 284is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL 285image can be encoded too but we don't do that. 286 287The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB, 288or 0x40 blocks. This is a severe and annoying limitation. There may be a way 289around this limitation, since there is plenty of SRAM, but at present the 290board refuses to boot if this limit is exceeded. 291 292The image produced is padded up to a block boundary (512 bytes). It should be 293written to the start of an SD card using dd. 294 295Since this image is set to load U-Boot from the SD card at block offset, 296CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write 297u-boot-dtb.img to the SD card at that offset. See above for instructions. 298 299rkspi 300----- 301 302rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The 303resulting image is then spread out so that only the first 2KB of each 4KB 304sector is used. The header is the same as with rksd and the maximum size is 305also 32KB (before spreading). The image should be written to the start of 306SPI flash. 307 308See above for instructions on how to write a SPI image. 309 310rkmux.py 311-------- 312 313You can use this script to create #defines for SoC register access. See the 314script for usage. 315 316 317Device tree and driver model 318---------------------------- 319 320Where possible driver model is used to provide a structure to the 321functionality. Device tree is used for configuration. However these have an 322overhead and in SPL with a 32KB size limit some shortcuts have been taken. 323In general all Rockchip drivers should use these features, with SPL-specific 324modifications where required. 325 326GPT partition layout 327---------------------------- 328 329Rockchip use a unified GPT partition layout in open source support. 330With this GPT partition layout, uboot can be compatilbe with other components, 331like miniloader, trusted-os, arm-trust-firmware. 332 333There are some documents about partitions in the links below. 334http://rockchip.wikidot.com/partitions 335 336-- 337Simon Glass <sjg@chromium.org> 33824 June 2015 339