xref: /openbmc/u-boot/board/sunxi/README.sunxi64 (revision 9ab403d0)
1Allwinner 64-bit boards README
2==============================
3
4Newer Allwinner SoCs feature ARMv8 cores (ARM Cortex-A53) with support for
5both the 64-bit AArch64 mode and the ARMv7 compatible 32-bit AArch32 mode.
6Examples are the Allwinner A64 (used for instance on the Pine64 board) or
7the Allwinner H5 SoC (as used on the OrangePi PC 2).
8These SoCs are wired to start in AArch32 mode on reset and execute 32-bit
9code from the Boot ROM (BROM). As this has some implications on U-Boot, this
10file describes how to make full use of the 64-bit capabilities.
11
12Quick Start / Overview
13======================
14- Build the ARM Trusted Firmware binary (see "ARM Trusted Firmware (ATF)" below)
15  $ cd /src/arm-trusted-firmware
16  $ make PLAT=sun50i_a64 DEBUG=1 bl31
17- Build U-Boot (see "SPL/U-Boot" below)
18  $ export BL31=/path/to/bl31.bin
19  $ make pine64_plus_defconfig && make -j5
20- Transfer to an uSD card (see "microSD card" below)
21  $ dd if=u-boot-sunxi-with-spl.bin of=/dev/sdx bs=8k seek=1
22- Boot and enjoy!
23
24Building the firmware
25=====================
26
27The Allwinner A64/H5 firmware consists of three parts: U-Boot's SPL, an
28ARM Trusted Firmware (ATF) build and the U-Boot proper.
29The SPL will load both ATF and U-Boot proper along with the right device
30tree blob (.dtb) and will pass execution to ATF (in EL3), which in turn will
31drop into the U-Boot proper (in EL2).
32As the ATF binary will become part of the U-Boot image file, you will need
33to build it first.
34
35 ARM Trusted Firmware (ATF)
36----------------------------
37Checkout the latest master branch from the official ATF repository [1] and
38build it:
39$ export CROSS_COMPILE=aarch64-linux-gnu-
40$ make PLAT=sun50i_a64 DEBUG=1 bl31
41The resulting binary is build/sun50i_a64/debug/bl31.bin. Either put the
42location of this file into the BL31 environment variable or copy this to
43the root of your U-Boot build directory (or create a symbolic link).
44$ export BL31=/src/arm-trusted-firmware/build/sun50i_a64/debug/bl31.bin
45  (adjust the actual path accordingly)
46The platform target "sun50i_a64" covers all boards with either an Allwinner
47A64 or H5 SoC (since they are very similar). For boards with an Allwinner H6
48SoC use "sun50i_h6".
49
50If you run into size issues with the resulting U-Boot image file, it might
51help to use a release build, by using "DEBUG=0" when building bl31.bin.
52As sometimes the ATF build process is a bit picky about the toolchain used,
53or if you can't be bothered with building ATF, there are known working
54binaries in the firmware repository[3], purely for convenience reasons.
55
56 SPL/U-Boot
57------------
58Both U-Boot proper and the SPL are using the 64-bit mode. As the boot ROM
59enters the SPL still in AArch32 secure SVC mode, there is some shim code to
60enter AArch64 very early. The rest of the SPL runs in AArch64 EL3.
61U-Boot proper runs in EL2 and can load any AArch64 code (using the "go"
62command), EFI applications (with "bootefi") or arm64 Linux kernel images
63(often named "Image"), using the "booti" command.
64
65$ make clean
66$ export CROSS_COMPILE=aarch64-linux-gnu-
67$ make pine64_plus_defconfig
68$ make
69
70This will build the SPL in spl/sunxi-spl.bin and a FIT image called u-boot.itb,
71which contains the rest of the firmware. u-boot-sunxi-with-spl.bin joins those
72two components in one convenient image file.
73
74
75Boot process
76============
77The on-die BROM code will try several methods to load and execute the firmware.
78On a typical board like the Pine64 this will result in the following boot order:
79
801) Reading 32KB from sector 16 (@8K) of the microSD card to SRAM A1. If the
81BROM finds the magic "eGON" header in the first bytes, it will execute that
82code. If not (no SD card at all or invalid magic), it will:
832) Try to read 32KB from sector 16 (@8K) of memory connected to the MMC2
84controller, typically an on-board eMMC chip. If there is no eMMC or it does
85not contain a valid boot header, it will:
863) Initialize the SPI0 controller and try to access a NOR flash connected to
87it (using the CS0 pin). If a flash chip is found, the BROM will load the
88first 32KB (from offset 0) into SRAM A1. Now it checks for the magic eGON
89header and checksum and will execute the code upon finding it. If not, it will:
904) Initialize the USB OTG controller and will wait for a host to connect to
91it, speaking the Allwinner proprietary (but deciphered) "FEL" USB protocol.
92
93
94To boot the Pine64 board, you can use U-Boot and any of the described methods.
95
96FEL boot (USB OTG)
97------------------
98FEL is the name of the Allwinner defined USB boot protocol built in the
99mask ROM of most Allwinner SoCs. It allows to bootstrap a board solely
100by using the USB-OTG interface and a host port on another computer.
101As the FEL mode is controlled by the boot ROM, it expects to be running in
102AArch32. For now the AArch64 SPL cannot properly return into FEL mode, so the
103feature is disabled in the configuration at the moment.
104The repository in [3] contains FEL capable SPL binaries, built using an
105off-tree branch to generate 32-bit ARM code (along with instructions
106how to re-create them).
107
108microSD card
109------------
110Transfer the SPL and the U-Boot FIT image directly to an uSD card:
111# dd if=spl/sunxi-spl.bin of=/dev/sdx bs=8k seek=1
112# dd if=u-boot.itb of=/dev/sdx bs=8k seek=5
113# sync
114(replace /dev/sdx with you SD card device file name, which could be
115/dev/mmcblk[x] as well).
116
117Alternatively you can use the SPL and the U-Boot FIT image combined into a
118single file and transfer that instead:
119# dd if=u-boot-sunxi-with-spl.bin of=/dev/sdx bs=8k seek=1
120
121You can partition the microSD card, but leave the first MB unallocated (most
122partitioning tools will do this anyway).
123
124NOR flash
125---------
126Some boards (like the SoPine, Pinebook or the OrangePi PC2) come with a
127soldered SPI NOR flash chip. On other boards like the Pine64 such a chip
128can be connected to the SPI0/CS0 pins on the PI-2 headers.
129Create the SPL and FIT image like described above for the SD card.
130Now connect either an "A to A" USB cable to the upper USB port on the Pine64
131or get an adaptor and use a regular A-microB cable connected to it. Other
132boards often have a proper micro-B USB socket connected to the USB OTB port.
133Remove a microSD card from the slot and power on the board.
134On your host computer download and build the sunxi-tools package[2], then
135use "sunxi-fel" to access the board:
136$ ./sunxi-fel ver -v -p
137This should give you an output starting with: AWUSBFEX soc=00001689(A64) ...
138Now use the sunxi-fel tool to write to the NOR flash:
139$ ./sunxi-fel spiflash-write 0 spl/sunxi-spl.bin
140$ ./sunxi-fel spiflash-write 32768 u-boot.itb
141Now boot the board without an SD card inserted and you should see the
142U-Boot prompt on the serial console.
143
144(Legacy) boot0 method
145---------------------
146boot0 is Allwinner's secondary program loader and it can be used as some kind
147of SPL replacement to get U-Boot up and running from an microSD card.
148For some time using boot0 was the only option to get the Pine64 booted.
149With working DRAM init code in U-Boot's SPL this is no longer necessary,
150but this method is described here for the sake of completeness.
151Please note that this method works only with the boot0 files shipped with
152A64 based boards, the H5 uses an incompatible layout which is not supported
153by this method.
154
155The boot0 binary is a 32 KByte blob and contained in the official Pine64 images
156distributed by Pine64 or Allwinner. It can be easily extracted from a micro
157SD card or an image file:
158# dd if=/dev/sd<x> of=boot0.bin bs=8k skip=1 count=4
159where /dev/sd<x> is the device name of the uSD card or the name of the image
160file. Apparently Allwinner allows re-distribution of this proprietary code
161"as-is".
162This boot0 blob takes care of DRAM initialisation and loads the remaining
163firmware parts, then switches the core into AArch64 mode.
164The original boot0 code looks for U-Boot at a certain place on an uSD card
165(at 19096 KB), also it expects a header with magic bytes and a checksum.
166There is a tool called boot0img[3] which takes a boot0.bin image and a compiled
167U-Boot binary (plus other binaries) and will populate that header accordingly.
168To make space for the magic header, the pine64_plus_defconfig will make sure
169there is sufficient space at the beginning of the U-Boot binary.
170boot0img will also take care of putting the different binaries at the right
171places on the uSD card and works around unused, but mandatory parts by using
172trampoline code. See the output of "boot0img -h" for more information.
173boot0img can also patch boot0 to avoid loading U-Boot from 19MB, instead
174fetching it from just behind the boot0 binary (-B option).
175$ ./boot0img -o firmware.img -B boot0.img -u u-boot-dtb.bin -e -s bl31.bin \
176-a 0x44008 -d trampoline64:0x44000
177Then write this image to a microSD card, replacing /dev/sdx with the right
178device file (see above):
179$ dd if=firmware.img of=/dev/sdx bs=8k seek=1
180
181[1] https://github.com/ARM-software/arm-trusted-firmware.git
182[2] git://github.com/linux-sunxi/sunxi-tools.git
183[3] https://github.com/apritzel/pine64/
184