summaryrefslogtreecommitdiff
path: root/doc/README.rockchip
blob: 9a2ebca95df668cc11af1858d8877b1bc00df6a3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
#
# Copyright (C) 2015 Google. Inc
# Written by Simon Glass <sjg@chromium.org>
#
# SPDX-License-Identifier:	GPL-2.0+
#

U-Boot on Rockchip
==================

There are several repositories available with versions of U-Boot that support
many Rockchip devices [1] [2].

The current mainline support is experimental only and is not useful for
anything. It should provide a base on which to build.

So far only support for the RK3288 is provided.


Prerequisites
=============

You will need:

   - Firefly RK3288 baord
   - Power connection to 5V using the supplied micro-USB power cable
   - Separate USB serial cable attached to your computer and the Firefly
        (connect to the micro-USB connector below the logo)
   - rkflashtool [3]
   - openssl (sudo apt-get install openssl)
   - Serial UART connection [4]
   - Suitable ARM cross compiler, e.g.:
        sudo apt-get install gcc-4.7-arm-linux-gnueabi


Building
========

At present three RK3288 boards are supported:

   - Firefly RK3288 - use firefly-rk3288 configuration
   - Radxa Rock 2 - also uses firefly-rk3288 configuration
   - Haier Chromebook - use chromebook_jerry configuration

one RK3036 board is support:

   - EVB RK3036 - use evb-rk3036_defconfig configuration

For example:

   CROSS_COMPILE=arm-linux-gnueabi- make O=firefly firefly-rk3288_defconfig all

(or you can use another cross compiler if you prefer)

Note that the Radxa Rock 2 uses the Firefly configuration for now as
device tree files are not yet available for the Rock 2. Clearly the two
have hardware differences, so this approach will break down as more drivers
are added.


Writing to the board with USB
=============================

For USB to work you must get your board into ROM boot mode, either by erasing
your MMC or (perhaps) holding the recovery button when you boot the board.
To erase your MMC, you can boot into Linux and type (as root)

   dd if=/dev/zero of=/dev/mmcblk0 bs=1M

Connect your board's OTG port to your computer.

To create a suitable image and write it to the board:

   ./firefly-rk3288/tools/mkimage -n rk3288 -T rkimage -d \
	./firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
   cat out | openssl rc4 -K 7c4e0304550509072d2c7b38170d1711 | rkflashtool l

If all goes well you should something like:

   U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 10:06:49)
   Card did not respond to voltage select!
   spl: mmc init failed with error: -17
   ### ERROR ### Please RESET the board ###

You will need to reset the board before each time you try. Yes, that's all
it does so far. If support for the Rockchip USB protocol or DFU were added
in SPL then we could in principle load U-Boot and boot to a prompt from USB
as several other platforms do. However it does not seem to be possible to
use the existing boot ROM code from SPL.


Booting from an SD card
=======================

To write an image that boots from an SD card (assumed to be /dev/sdc):

   ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \
	firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
   sudo dd if=out of=/dev/sdc seek=64 && \
   sudo dd if=firefly-rk3288/u-boot-dtb.img of=/dev/sdc seek=256

This puts the Rockchip header and SPL image first and then places the U-Boot
image at block 256 (i.e. 128KB from the start of the SD card). This
corresponds with this setting in U-Boot:

   #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR	256

Put this SD (or micro-SD) card into your board and reset it. You should see
something like:

   U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 11:04:40)


   U-Boot 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 11:04:40)

   DRAM:  2 GiB
   MMC:
   Using default environment

   In:    serial@ff690000
   Out:   serial@ff690000
   Err:   serial@ff690000
   =>

For evb_rk3036 board:
	./evb-rk3036/tools/mkimage -n rk3036 -T rksd  -d evb-rk3036/spl/u-boot-spl.bin out && \
	cat evb-rk3036/u-boot-dtb.bin >> out && \
	sudo dd if=out of=/dev/sdc seek=64

Note: rk3036 SDMMC and debug uart use the same iomux, so if you boot from SD, the
      debug uart must be disabled

Booting from SPI
================

To write an image that boots from SPI flash (e.g. for the Haier Chromebook):

   ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \
	-d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \
   dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \
   cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \
   dd if=out.bin of=out.bin.pad bs=4M conv=sync

This converts the SPL image to the required SPI format by adding the Rockchip
header and skipping every 2KB block. Then the U-Boot image is written at
offset 128KB and the whole image is padded to 4MB which is the SPI flash size.
The position of U-Boot is controlled with this setting in U-Boot:

   #define CONFIG_SYS_SPI_U_BOOT_OFFS	(128 << 10)

If you have a Dediprog em100pro connected then you can write the image with:

      sudo em100 -s -c GD25LQ32 -d out.bin.pad -r

When booting you should see something like:

   U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32)


   U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600)

   Model: Google Jerry
   DRAM:  2 GiB
   MMC:
   Using default environment

   In:    serial@ff690000
   Out:   serial@ff690000
   Err:   serial@ff690000
   =>


Future work
===========

Immediate priorities are:

- GPIO (driver exists but is lightly tested)
- I2C (driver exists but is non-functional)
- USB host
- USB device
- PMIC and regulators (only ACT8846 is supported at present)
- LCD and HDMI
- Run CPU at full speed
- Ethernet
- NAND flash
- Support for other Rockchip parts
- Boot U-Boot proper over USB OTG (at present only SPL works)


Development Notes
=================

There are plenty of patches in the links below to help with this work.

[1] https://github.com/rkchrome/uboot.git
[2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288
[3] https://github.com/linux-rockchip/rkflashtool.git
[4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en

rkimage
-------

rkimage.c produces an SPL image suitable for sending directly to the boot ROM
over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes)
followed by u-boot-spl-dtb.bin.

The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM
starts at 0xff700000 and extends to 0xff718000 where we put the stack.

rksd
----

rksd.c produces an image consisting of 32KB of empty space, a header and
u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although
most of the fields are unused by U-Boot. We just need to specify the
signature, a flag and the block offset and size of the SPL image.

The header occupies a single block but we pad it out to 4 blocks. The header
is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL
image can be encoded too but we don't do that.

The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB,
or 0x40 blocks. This is a severe and annoying limitation. There may be a way
around this limitation, since there is plenty of SRAM, but at present the
board refuses to boot if this limit is exceeded.

The image produced is padded up to a block boundary (512 bytes). It should be
written to the start of an SD card using dd.

Since this image is set to load U-Boot from the SD card at block offset,
CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write
u-boot-dtb.img to the SD card at that offset. See above for instructions.

rkspi
-----

rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The
resulting image is then spread out so that only the first 2KB of each 4KB
sector is used. The header is the same as with rksd and the maximum size is
also 32KB (before spreading). The image should be written to the start of
SPI flash.

See above for instructions on how to write a SPI image.


Device tree and driver model
----------------------------

Where possible driver model is used to provide a structure to the
functionality. Device tree is used for configuration. However these have an
overhead and in SPL with a 32KB size limit some shortcuts have been taken.
In general all Rockchip drivers should use these features, with SPL-specific
modifications where required.


--
Simon Glass <sjg@chromium.org>
24 June 2015