mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-21 02:33:07 +00:00
e72a6be4fc
Allwinner sun50i SoCs contain an OpenRISC 1000 CPU that functions as a System Control Processor, or SCP. ARM Trusted Firmware (ATF) communicates with the SCP over SCPI to implement the PSCI system suspend, shutdown and reset functionality. Currently, SCP firmware is optional; the system will boot and run without it, but system suspend will be unavailable. Since all communication with the SCP is mediated by ATF, the only thing U-Boot needs to do is load the firmware into SRAM. The SCP firmware occupies the last 16KiB of SRAM A2, immediately following ATF. Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Samuel Holland <samuel@sholland.org> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
216 lines
10 KiB
Text
216 lines
10 KiB
Text
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/
|