xref: /openbmc/u-boot/doc/README.rockchip (revision 9ec4a67e)
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 seven 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   - Miniarm RK3288 - use miniarm-rk3288 configuration
46   - PopMetal RK3288 - use popmetal-rk3288 configuration
47   - Radxa Rock 2 - use rock2 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=256
101
102This puts the Rockchip header and SPL image first and then places the U-Boot
103image at block 256 (i.e. 128KB 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	256
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-level bootloader(ie. U-BOOT) as soon as it returns to bootrom.
128Therefore RK3288 has another loading sequence like RK3036. The option of
129U-Boot is controlled with this setting in U-Boot:
130
131	#define CONFIG_ROCKCHIP_SPL_BACK_TO_BROM
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
150Using fastboot on rk3288
151========================
152- Write GPT partition layout to mmc device which fastboot want to use it to
153store the image
154
155        => gpt write mmc 1 $partitions
156
157- Invoke fastboot command to prepare
158
159        => fastboot 1
160
161- Start fastboot request on PC
162
163        fastboot -i 0x2207 flash loader evb-rk3288/spl/u-boot-spl-dtb.bin
164
165You should see something like:
166
167        => fastboot 1
168        WARNING: unknown variable: partition-type:loader
169        Starting download of 357796 bytes
170        ..
171        downloading of 357796 bytes finished
172        Flashing Raw Image
173        ........ wrote 357888 bytes to 'loader'
174
175Booting from SPI
176================
177
178To write an image that boots from SPI flash (e.g. for the Haier Chromebook):
179
180   ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \
181	-d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \
182   dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \
183   cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \
184   dd if=out.bin of=out.bin.pad bs=4M conv=sync
185
186This converts the SPL image to the required SPI format by adding the Rockchip
187header and skipping every 2KB block. Then the U-Boot image is written at
188offset 128KB and the whole image is padded to 4MB which is the SPI flash size.
189The position of U-Boot is controlled with this setting in U-Boot:
190
191   #define CONFIG_SYS_SPI_U_BOOT_OFFS	(128 << 10)
192
193If you have a Dediprog em100pro connected then you can write the image with:
194
195      sudo em100 -s -c GD25LQ32 -d out.bin.pad -r
196
197When booting you should see something like:
198
199   U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32)
200
201
202   U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600)
203
204   Model: Google Jerry
205   DRAM:  2 GiB
206   MMC:
207   Using default environment
208
209   In:    serial@ff690000
210   Out:   serial@ff690000
211   Err:   serial@ff690000
212   =>
213
214Future work
215===========
216
217Immediate priorities are:
218
219- USB host
220- USB device
221- Run CPU at full speed (code exists but we only see ~60 DMIPS maximum)
222- Ethernet
223- NAND flash
224- Support for other Rockchip parts
225- Boot U-Boot proper over USB OTG (at present only SPL works)
226
227
228Development Notes
229=================
230
231There are plenty of patches in the links below to help with this work.
232
233[1] https://github.com/rkchrome/uboot.git
234[2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288
235[3] https://github.com/linux-rockchip/rkflashtool.git
236[4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en
237
238rkimage
239-------
240
241rkimage.c produces an SPL image suitable for sending directly to the boot ROM
242over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes)
243followed by u-boot-spl-dtb.bin.
244
245The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM
246starts at 0xff700000 and extends to 0xff718000 where we put the stack.
247
248rksd
249----
250
251rksd.c produces an image consisting of 32KB of empty space, a header and
252u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although
253most of the fields are unused by U-Boot. We just need to specify the
254signature, a flag and the block offset and size of the SPL image.
255
256The header occupies a single block but we pad it out to 4 blocks. The header
257is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL
258image can be encoded too but we don't do that.
259
260The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB,
261or 0x40 blocks. This is a severe and annoying limitation. There may be a way
262around this limitation, since there is plenty of SRAM, but at present the
263board refuses to boot if this limit is exceeded.
264
265The image produced is padded up to a block boundary (512 bytes). It should be
266written to the start of an SD card using dd.
267
268Since this image is set to load U-Boot from the SD card at block offset,
269CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write
270u-boot-dtb.img to the SD card at that offset. See above for instructions.
271
272rkspi
273-----
274
275rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The
276resulting image is then spread out so that only the first 2KB of each 4KB
277sector is used. The header is the same as with rksd and the maximum size is
278also 32KB (before spreading). The image should be written to the start of
279SPI flash.
280
281See above for instructions on how to write a SPI image.
282
283rkmux.py
284--------
285
286You can use this script to create #defines for SoC register access. See the
287script for usage.
288
289
290Device tree and driver model
291----------------------------
292
293Where possible driver model is used to provide a structure to the
294functionality. Device tree is used for configuration. However these have an
295overhead and in SPL with a 32KB size limit some shortcuts have been taken.
296In general all Rockchip drivers should use these features, with SPL-specific
297modifications where required.
298
299GPT partition layout
300----------------------------
301
302Rockchip use a unified GPT partition layout  in open source support.
303With this GPT partition layout, uboot can be compatilbe with other components,
304like miniloader, trusted-os, arm-trust-firmware.
305
306There are some documents about partitions in the links below.
307http://rockchip.wikidot.com/partitions
308
309--
310Simon Glass <sjg@chromium.org>
31124 June 2015
312