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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- Build U-Boot (see "SPL/U-Boot" below)
16- Transfer to an uSD card (see "microSD card" below)
17- Boot and enjoy!
18
19Building the firmware
20=====================
21
22The Allwinner A64/H5 firmware consists of three parts: U-Boot's SPL, an
23ARM Trusted Firmware (ATF) build and the U-Boot proper.
24The SPL will load both ATF and U-Boot proper along with the right device
25tree blob (.dtb) and will pass execution to ATF (in EL3), which in turn will
26drop into the U-Boot proper (in EL2).
27As the ATF binary will become part of the U-Boot image file, you will need
28to build it first.
29
30 ARM Trusted Firmware (ATF)
31----------------------------
32Checkout the "allwinner" branch from the github repository [1] and build it:
33$ export CROSS_COMPILE=aarch64-linux-gnu-
34$ make PLAT=sun50iw1p1 DEBUG=1 bl31
35The resulting binary is build/sun50iw1p1/debug/bl31.bin. Either put the
36location of this file into the BL31 environment variable or copy this to
37the root of your U-Boot build directory (or create a symbolic link).
38$ export BL31=/src/arm-trusted-firmware/build/sun50iw1p1/debug/bl31.bin
39  (adjust the actual path accordingly)
40
41If you run into size issues with the resulting U-Boot image file, it might
42help to use a release build, by using "DEBUG=0" when building bl31.bin.
43As sometimes the ATF build process is a bit picky about the toolchain used,
44or if you can't be bothered with building ATF, there are known working
45binaries in the firmware repository[3], purely for convenience reasons.
46
47 SPL/U-Boot
48------------
49Both U-Boot proper and the SPL are using the 64-bit mode. As the boot ROM
50enters the SPL still in AArch32 secure SVC mode, there is some shim code to
51enter AArch64 very early. The rest of the SPL runs in AArch64 EL3.
52U-Boot proper runs in EL2 and can load any AArch64 code (using the "go"
53command), EFI applications (with "bootefi") or arm64 Linux kernel images
54(often named "Image"), using the "booti" command.
55
56$ make clean
57$ export CROSS_COMPILE=aarch64-linux-gnu-
58$ make pine64_plus_defconfig
59$ make
60
61This will build the SPL in spl/sunxi-spl.bin and a FIT image called u-boot.itb,
62which contains the rest of the firmware.
63
64
65Boot process
66============
67The on-die BROM code will try several methods to load and execute the firmware.
68On a typical board like the Pine64 this will result in the following boot order:
69
701) Reading 32KB from sector 16 (@8K) of the microSD card to SRAM A1. If the
71BROM finds the magic "eGON" header in the first bytes, it will execute that
72code. If not (no SD card at all or invalid magic), it will:
732) Try to read 32KB from sector 16 (@8K) of memory connected to the MMC2
74controller, typically an on-board eMMC chip. If there is no eMMC or it does
75not contain a valid boot header, it will:
763) Initialize the SPI0 controller and try to access a NOR flash connected to
77it (using the CS0 pin). If a flash chip is found, the BROM will load the
78first 32KB (from offset 0) into SRAM A1. Now it checks for the magic eGON
79header and checksum and will execute the code upon finding it. If not, it will:
804) Initialize the USB OTG controller and will wait for a host to connect to
81it, speaking the Allwinner proprietary (but deciphered) "FEL" USB protocol.
82
83
84To boot the Pine64 board, you can use U-Boot and any of the described methods.
85
86FEL boot (USB OTG)
87------------------
88FEL is the name of the Allwinner defined USB boot protocol built in the
89mask ROM of most Allwinner SoCs. It allows to bootstrap a board solely
90by using the USB-OTG interface and a host port on another computer.
91As the FEL mode is controlled by the boot ROM, it expects to be running in
92AArch32. For now the AArch64 SPL cannot properly return into FEL mode, so the
93feature is disabled in the configuration at the moment.
94
95microSD card
96------------
97Transfer the SPL and the U-Boot FIT image directly to an uSD card:
98# dd if=spl/sunxi-spl.bin of=/dev/sdx bs=8k seek=1
99# dd if=u-boot.itb of=/dev/sdx bs=8k seek=5
100# sync
101(replace /dev/sdx with you SD card device file name, which could be
102/dev/mmcblk[x] as well).
103
104Alternatively you can use the SPL and the U-Boot FIT image combined into a
105single file and transfer that instead:
106# dd if=u-boot-sunxi-with-spl.bin of=/dev/sdx bs=8k seek=1
107
108You can partition the microSD card, but leave the first MB unallocated (most
109partitioning tools will do this anyway).
110
111NOR flash
112---------
113Some boards (like the SoPine, Pinebook or the OrangePi PC2) come with a
114soldered SPI NOR flash chip. On other boards like the Pine64 such a chip
115can be connected to the SPI0/CS0 pins on the PI-2 headers.
116Create the SPL and FIT image like described above for the SD card.
117Now connect either an "A to A" USB cable to the upper USB port on the Pine64
118or get an adaptor and use a regular A-microB cable connected to it. Other
119boards often have a proper micro-B USB socket connected to the USB OTB port.
120Remove a microSD card from the slot and power on the board.
121On your host computer download and build the sunxi-tools package[2], then
122use "sunxi-fel" to access the board:
123$ ./sunxi-fel ver -v -p
124This should give you an output starting with: AWUSBFEX soc=00001689(A64) ...
125Now use the sunxi-fel tool to write to the NOR flash:
126$ ./sunxi-fel spiflash-write 0 spl/sunxi-spl.bin
127$ ./sunxi-fel spiflash-write 32768 u-boot.itb
128Now boot the board without an SD card inserted and you should see the
129U-Boot prompt on the serial console.
130
131(Legacy) boot0 method
132---------------------
133boot0 is Allwiner's secondary program loader and it can be used as some kind
134of SPL replacement to get U-Boot up and running from an microSD card.
135For some time using boot0 was the only option to get the Pine64 booted.
136With working DRAM init code in U-Boot's SPL this is no longer necessary,
137but this method is described here for the sake of completeness.
138Please note that this method works only with the boot0 files shipped with
139A64 based boards, the H5 uses an incompatible layout which is not supported
140by this method.
141
142The boot0 binary is a 32 KByte blob and contained in the official Pine64 images
143distributed by Pine64 or Allwinner. It can be easily extracted from a micro
144SD card or an image file:
145# dd if=/dev/sd<x> of=boot0.bin bs=8k skip=1 count=4
146where /dev/sd<x> is the device name of the uSD card or the name of the image
147file. Apparently Allwinner allows re-distribution of this proprietary code
148"as-is".
149This boot0 blob takes care of DRAM initialisation and loads the remaining
150firmware parts, then switches the core into AArch64 mode.
151The original boot0 code looks for U-Boot at a certain place on an uSD card
152(at 19096 KB), also it expects a header with magic bytes and a checksum.
153There is a tool called boot0img[3] which takes a boot0.bin image and a compiled
154U-Boot binary (plus other binaries) and will populate that header accordingly.
155To make space for the magic header, the pine64_plus_defconfig will make sure
156there is sufficient space at the beginning of the U-Boot binary.
157boot0img will also take care of putting the different binaries at the right
158places on the uSD card and works around unused, but mandatory parts by using
159trampoline code. See the output of "boot0img -h" for more information.
160boot0img can also patch boot0 to avoid loading U-Boot from 19MB, instead
161fetching it from just behind the boot0 binary (-B option).
162$ ./boot0img -o firmware.img -B boot0.img -u u-boot-dtb.bin -e -s bl31.bin \
163-a 0x44008 -d trampoline64:0x44000
164Then write this image to a microSD card, replacing /dev/sdx with the right
165device file (see above):
166$ dd if=firmware.img of=/dev/sdx bs=8k seek=1
167
168[1] https://github.com/apritzel/arm-trusted-firmware.git
169[2] git://github.com/linux-sunxi/sunxi-tools.git
170[3] https://github.com/apritzel/pine64/
171