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 Allwinner'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