| Allwinner 64-bit boards README |
| ============================== |
| |
| Newer Allwinner SoCs feature ARMv8 cores (ARM Cortex-A53) with support for |
| both the 64-bit AArch64 mode and the ARMv7 compatible 32-bit AArch32 mode. |
| Examples are the Allwinner A64 (used for instance on the Pine64 board) or |
| the Allwinner H5 SoC (as used on the OrangePi PC 2). |
| These SoCs are wired to start in AArch32 mode on reset and execute 32-bit |
| code from the Boot ROM (BROM). As this has some implications on U-Boot, this |
| file describes how to make full use of the 64-bit capabilities. |
| |
| Quick Start / Overview |
| ====================== |
| - Build the ARM Trusted Firmware binary (see "ARM Trusted Firmware (ATF)" below) |
| - Build U-Boot (see "SPL/U-Boot" below) |
| - Transfer to an uSD card (see "microSD card" below) |
| - Boot and enjoy! |
| |
| Building the firmware |
| ===================== |
| |
| The Allwinner A64/H5 firmware consists of three parts: U-Boot's SPL, an |
| ARM Trusted Firmware (ATF) build and the U-Boot proper. |
| The SPL will load both ATF and U-Boot proper along with the right device |
| tree blob (.dtb) and will pass execution to ATF (in EL3), which in turn will |
| drop into the U-Boot proper (in EL2). |
| As the ATF binary will become part of the U-Boot image file, you will need |
| to build it first. |
| |
| ARM Trusted Firmware (ATF) |
| ---------------------------- |
| Checkout the "allwinner" branch from the github repository [1] and build it: |
| $ export CROSS_COMPILE=aarch64-linux-gnu- |
| $ make PLAT=sun50iw1p1 DEBUG=1 bl31 |
| The resulting binary is build/sun50iw1p1/debug/bl31.bin. Either put the |
| location of this file into the BL31 environment variable or copy this to |
| the root of your U-Boot build directory (or create a symbolic link). |
| $ export BL31=/src/arm-trusted-firmware/build/sun50iw1p1/debug/bl31.bin |
| (adjust the actual path accordingly) |
| |
| If you run into size issues with the resulting U-Boot image file, it might |
| help to use a release build, by using "DEBUG=0" when building bl31.bin. |
| As sometimes the ATF build process is a bit picky about the toolchain used, |
| or if you can't be bothered with building ATF, there are known working |
| binaries in the firmware repository[3], purely for convenience reasons. |
| |
| SPL/U-Boot |
| ------------ |
| Both U-Boot proper and the SPL are using the 64-bit mode. As the boot ROM |
| enters the SPL still in AArch32 secure SVC mode, there is some shim code to |
| enter AArch64 very early. The rest of the SPL runs in AArch64 EL3. |
| U-Boot proper runs in EL2 and can load any AArch64 code (using the "go" |
| command), EFI applications (with "bootefi") or arm64 Linux kernel images |
| (often named "Image"), using the "booti" command. |
| |
| $ make clean |
| $ export CROSS_COMPILE=aarch64-linux-gnu- |
| $ make pine64_plus_defconfig |
| $ make |
| |
| This will build the SPL in spl/sunxi-spl.bin and a FIT image called u-boot.itb, |
| which contains the rest of the firmware. |
| |
| |
| Boot process |
| ============ |
| The on-die BROM code will try several methods to load and execute the firmware. |
| On a typical board like the Pine64 this will result in the following boot order: |
| |
| 1) Reading 32KB from sector 16 (@8K) of the microSD card to SRAM A1. If the |
| BROM finds the magic "eGON" header in the first bytes, it will execute that |
| code. If not (no SD card at all or invalid magic), it will: |
| 2) Try to read 32KB from sector 16 (@8K) of memory connected to the MMC2 |
| controller, typically an on-board eMMC chip. If there is no eMMC or it does |
| not contain a valid boot header, it will: |
| 3) Initialize the SPI0 controller and try to access a NOR flash connected to |
| it (using the CS0 pin). If a flash chip is found, the BROM will load the |
| first 32KB (from offset 0) into SRAM A1. Now it checks for the magic eGON |
| header and checksum and will execute the code upon finding it. If not, it will: |
| 4) Initialize the USB OTG controller and will wait for a host to connect to |
| it, speaking the Allwinner proprietary (but deciphered) "FEL" USB protocol. |
| |
| |
| To boot the Pine64 board, you can use U-Boot and any of the described methods. |
| |
| FEL boot (USB OTG) |
| ------------------ |
| FEL is the name of the Allwinner defined USB boot protocol built in the |
| mask ROM of most Allwinner SoCs. It allows to bootstrap a board solely |
| by using the USB-OTG interface and a host port on another computer. |
| As the FEL mode is controlled by the boot ROM, it expects to be running in |
| AArch32. For now the AArch64 SPL cannot properly return into FEL mode, so the |
| feature is disabled in the configuration at the moment. |
| |
| microSD card |
| ------------ |
| Transfer the SPL and the U-Boot FIT image directly to an uSD card: |
| # dd if=spl/sunxi-spl.bin of=/dev/sdx bs=8k seek=1 |
| # dd if=u-boot.itb of=/dev/sdx bs=8k seek=5 |
| # sync |
| (replace /dev/sdx with you SD card device file name, which could be |
| /dev/mmcblk[x] as well). |
| |
| Alternatively you can use the SPL and the U-Boot FIT image combined into a |
| single file and transfer that instead: |
| # dd if=u-boot-sunxi-with-spl.bin of=/dev/sdx bs=8k seek=1 |
| |
| You can partition the microSD card, but leave the first MB unallocated (most |
| partitioning tools will do this anyway). |
| |
| NOR flash |
| --------- |
| Some boards (like the SoPine, Pinebook or the OrangePi PC2) come with a |
| soldered SPI NOR flash chip. On other boards like the Pine64 such a chip |
| can be connected to the SPI0/CS0 pins on the PI-2 headers. |
| Create the SPL and FIT image like described above for the SD card. |
| Now connect either an "A to A" USB cable to the upper USB port on the Pine64 |
| or get an adaptor and use a regular A-microB cable connected to it. Other |
| boards often have a proper micro-B USB socket connected to the USB OTB port. |
| Remove a microSD card from the slot and power on the board. |
| On your host computer download and build the sunxi-tools package[2], then |
| use "sunxi-fel" to access the board: |
| $ ./sunxi-fel ver -v -p |
| This should give you an output starting with: AWUSBFEX soc=00001689(A64) ... |
| Now use the sunxi-fel tool to write to the NOR flash: |
| $ ./sunxi-fel spiflash-write 0 spl/sunxi-spl.bin |
| $ ./sunxi-fel spiflash-write 32768 u-boot.itb |
| Now boot the board without an SD card inserted and you should see the |
| U-Boot prompt on the serial console. |
| |
| (Legacy) boot0 method |
| --------------------- |
| boot0 is Allwinner's secondary program loader and it can be used as some kind |
| of SPL replacement to get U-Boot up and running from an microSD card. |
| For some time using boot0 was the only option to get the Pine64 booted. |
| With working DRAM init code in U-Boot's SPL this is no longer necessary, |
| but this method is described here for the sake of completeness. |
| Please note that this method works only with the boot0 files shipped with |
| A64 based boards, the H5 uses an incompatible layout which is not supported |
| by this method. |
| |
| The boot0 binary is a 32 KByte blob and contained in the official Pine64 images |
| distributed by Pine64 or Allwinner. It can be easily extracted from a micro |
| SD card or an image file: |
| # dd if=/dev/sd<x> of=boot0.bin bs=8k skip=1 count=4 |
| where /dev/sd<x> is the device name of the uSD card or the name of the image |
| file. Apparently Allwinner allows re-distribution of this proprietary code |
| "as-is". |
| This boot0 blob takes care of DRAM initialisation and loads the remaining |
| firmware parts, then switches the core into AArch64 mode. |
| The original boot0 code looks for U-Boot at a certain place on an uSD card |
| (at 19096 KB), also it expects a header with magic bytes and a checksum. |
| There is a tool called boot0img[3] which takes a boot0.bin image and a compiled |
| U-Boot binary (plus other binaries) and will populate that header accordingly. |
| To make space for the magic header, the pine64_plus_defconfig will make sure |
| there is sufficient space at the beginning of the U-Boot binary. |
| boot0img will also take care of putting the different binaries at the right |
| places on the uSD card and works around unused, but mandatory parts by using |
| trampoline code. See the output of "boot0img -h" for more information. |
| boot0img can also patch boot0 to avoid loading U-Boot from 19MB, instead |
| fetching it from just behind the boot0 binary (-B option). |
| $ ./boot0img -o firmware.img -B boot0.img -u u-boot-dtb.bin -e -s bl31.bin \ |
| -a 0x44008 -d trampoline64:0x44000 |
| Then write this image to a microSD card, replacing /dev/sdx with the right |
| device file (see above): |
| $ dd if=firmware.img of=/dev/sdx bs=8k seek=1 |
| |
| [1] https://github.com/apritzel/arm-trusted-firmware.git |
| [2] git://github.com/linux-sunxi/sunxi-tools.git |
| [3] https://github.com/apritzel/pine64/ |