doc: arch: Convert README.mips to reST
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>
diff --git a/doc/arch/mips.rst b/doc/arch/mips.rst
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+.. 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