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diff --git a/roms/u-boot/board/sunxi/README.sunxi64 b/roms/u-boot/board/sunxi/README.sunxi64 new file mode 100644 index 000000000..4803bc9ff --- /dev/null +++ b/roms/u-boot/board/sunxi/README.sunxi64 @@ -0,0 +1,216 @@ +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) + $ cd /src/arm-trusted-firmware + $ make PLAT=sun50i_a64 DEBUG=1 bl31 +- Build the SCP firmware binary (see "SCP firmware (Crust)" below) + $ cd /src/crust + $ make pine64_plus_defconfig && make -j5 scp +- Build U-Boot (see "SPL/U-Boot" below) + $ export BL31=/path/to/bl31.bin + $ export SCP=/src/crust/build/scp/scp.bin + $ make pine64_plus_defconfig && make -j5 +- Transfer to an uSD card (see "microSD card" below) + $ dd if=u-boot-sunxi-with-spl.bin of=/dev/sdx bs=8k seek=1 +- Boot and enjoy! + +Building the firmware +===================== + +The Allwinner A64/H5/H6 firmware consists of several parts: U-Boot's SPL, +ARM Trusted Firmware (ATF), optional System Control Processor (SCP) firmware +(e.g. Crust), and the U-Boot proper. + +The SPL will load all of the other firmware binaries into RAM, along with the +right device tree blob (.dtb), and will pass execution to ATF (in EL3). If SCP +firmware was loaded, ATF will power on the SCP and wait for it to boot. +ATF will then drop into U-Boot proper (in EL2). + +As the ATF binary and SCP firmware will become part of the U-Boot image file, +you will need to build them first. + + ARM Trusted Firmware (ATF) +---------------------------- +Checkout the latest master branch from the official ATF repository [1] and +build it: +$ export CROSS_COMPILE=aarch64-linux-gnu- +$ make PLAT=sun50i_a64 DEBUG=1 bl31 +The resulting binary is build/sun50i_a64/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/sun50i_a64/debug/bl31.bin + (adjust the actual path accordingly) +The platform target "sun50i_a64" covers all boards with either an Allwinner +A64 or H5 SoC (since they are very similar). For boards with an Allwinner H6 +SoC use "sun50i_h6". + +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. + + SCP firmware (Crust) +---------------------- +SCP firmware is responsible for implementing system suspend/resume, and (on +boards without a PMIC) soft poweroff/on. ATF contains fallback code for CPU +power control, so SCP firmware is optional if you don't need either of these +features. It runs on the AR100, with is an or1k CPU, not ARM, so it needs a +different cross toolchain. + +There is one SCP firmware implementation currently available, Crust: +$ git clone https://github.com/crust-firmware/crust +$ cd crust +$ export CROSS_COMPILE=or1k-linux-musl- +$ make pine64_plus_defconfig +$ make scp + +The same configuration generally works on any board with the same SoC (A64, H5, +or H6), so if there is no config for your board, use one for a similar board. + +Like for ATF, U-Boot finds the SCP firmware binary via an environment variable: +$ export SCP=/src/crust/build/scp/scp.bin + +If you do not want to use SCP firmware, you can silence the warning from binman +by pointing it to an empty file: +$ export SCP=/dev/null + + 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. u-boot-sunxi-with-spl.bin joins those +two components in one convenient image file. + + +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. +The repository in [3] contains FEL capable SPL binaries, built using an +off-tree branch to generate 32-bit ARM code (along with instructions +how to re-create them). + +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/ARM-software/arm-trusted-firmware.git +[2] git://github.com/linux-sunxi/sunxi-tools.git +[3] https://github.com/apritzel/pine64/ |