Add submodule dependency filesHEADmaster

Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec

1 files changed, 46 insertions, 0 deletions

diff --git a/roms/u-boot/doc/arch/mips.rst b/roms/u-boot/doc/arch/mips.rst
new file mode 100644
index 000000000..b8166087d
--- /dev/null
+++ b/roms/u-boot/doc/arch/mips.rst
@@ -0,0 +1,46 @@
+.. 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