mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-18 10:48:51 +00:00
5f2c16dab2
Convert plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
46 lines
1.7 KiB
ReStructuredText
46 lines
1.7 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
|
|
|
|
MIPS
|
|
====
|
|
|
|
Notes for the MIPS architecture port of U-Boot
|
|
|
|
Toolchains
|
|
----------
|
|
|
|
* `ELDK < DULG < DENX <http://www.denx.de/wiki/DULG/ELDK>`_
|
|
* `Embedded Debian -- Cross-development toolchains <http://www.emdebian.org/crosstools.html>`_
|
|
* `Buildroot <http://buildroot.uclibc.org/>`_
|
|
|
|
Known Issues
|
|
------------
|
|
|
|
* Cache incoherency issue caused by do_bootelf_exec() at cmd_elf.c
|
|
|
|
Cache will be disabled before entering the loaded ELF image without
|
|
writing back and invalidating cache lines. This leads to cache
|
|
incoherency in most cases, unless the code gets loaded after U-Boot
|
|
re-initializes the cache. The more common uImage 'bootm' command does
|
|
not suffer this problem.
|
|
|
|
[workaround] To avoid this cache incoherency:
|
|
- insert flush_cache(all) before calling dcache_disable(), or
|
|
- fix dcache_disable() to do both flushing and disabling cache.
|
|
|
|
* Note that Linux users need to kill dcache_disable() in do_bootelf_exec()
|
|
or override do_bootelf_exec() not to disable I-/D-caches, because most
|
|
Linux/MIPS ports don't re-enable caches after entering kernel_entry.
|
|
|
|
TODOs
|
|
-----
|
|
|
|
* Probe CPU types, I-/D-cache and TLB size etc. automatically
|
|
* Secondary cache support missing
|
|
* Initialize TLB entries redardless of their use
|
|
* R2000/R3000 class parts are not supported
|
|
* Limited testing across different MIPS variants
|
|
* Due to cache initialization issues, the DRAM on board must be
|
|
initialized in board specific assembler language before the cache init
|
|
code is run -- that is, initialize the DRAM in lowlevel_init().
|
|
* centralize/share more CPU code of MIPS32, MIPS64 and XBurst
|
|
* support Qemu Malta
|