mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-25 12:33:41 +00:00
47 lines
1.7 KiB
Text
47 lines
1.7 KiB
Text
|
U-boot for arm64
|
||
|
|
|
||
|
|
Summary
|
||
|
|
=======
|
||
|
|
No hardware platform of arm64 is available now. The u-boot is
|
||
|
|
simulated on Foundation Model and Fast Model for ARMv8.
|
||
|
|
|
||
|
|
Notes
|
||
|
|
=====
|
||
|
|
|
||
|
|
1. Currenly, u-boot run at the highest exception level processor
|
||
|
|
supported and jump to EL2 or optionally EL1 before enter OS.
|
||
|
|
|
||
|
|
2. U-boot for arm64 is compiled with AArch64-gcc. AArch64-gcc
|
||
|
|
use rela relocation format, a tool(tools/relocate-rela) by Scott Wood
|
||
|
|
is used to encode the initial addend of rela to u-boot.bin. After running,
|
||
|
|
the u-boot will be relocated to destination again.
|
||
|
|
|
||
|
|
3. Fdt should be placed at a 2-megabyte boundary and within the first 512
|
||
|
|
megabytes from the start of the kernel image. So, fdt_high should be
|
||
|
|
defined specially.
|
||
|
|
Please reference linux/Documentation/arm64/booting.txt for detail.
|
||
|
|
|
||
|
|
4. Spin-table is used to wake up secondary processors. One location
|
||
|
|
(or per processor location) is defined to hold the kernel entry point
|
||
|
|
for secondary processors. It must be ensured that the location is
|
||
|
|
accessible and zero immediately after secondary processor
|
||
|
|
enter slave_cpu branch execution in start.S. The location address
|
||
|
|
is encoded in cpu node of DTS. Linux kernel store the entry point
|
||
|
|
of secondary processors to it and send event to wakeup secondary
|
||
|
|
processors.
|
||
|
|
Please reference linux/Documentation/arm64/booting.txt for detail.
|
||
|
|
|
||
|
|
5. Generic board is supported.
|
||
|
|
|
||
|
|
6. CONFIG_ARM64 instead of CONFIG_ARMV8 is used to distinguish aarch64 and
|
||
|
|
aarch32 specific codes.
|
||
|
|
|
||
|
|
Contributor
|
||
|
|
===========
|
||
|
|
Tom Rini <trini@ti.com>
|
||
|
|
Scott Wood <scottwood@freescale.com>
|
||
|
|
York Sun <yorksun@freescale.com>
|
||
|
|
Simon Glass <sjg@chromium.org>
|
||
|
|
Sharma Bhupesh <bhupesh.sharma@freescale.com>
|
||
|
|
Rob Herring <robherring2@gmail.com>
|