xref: /openbmc/u-boot/doc/README.rockchip (revision 2d1951fe)
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