xref: /openbmc/u-boot/doc/README.rockchip (revision b2153075)
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