139c949f7f
mt7621 has the following memory map:
0x0-0x1c000000: lower 448m memory
0x1c000000-0x2000000: peripheral registers
0x20000000-0x2400000: higher 64m memory
detect_memory_region in arch/mips/kernel/setup.c only adds the first
memory region and isn't suitable for 512m memory detection because
it may accidentally read the memory area for peripheral registers.
This commit adds memory detection capability for mt7621:
1. Add the highmem area when 512m is detected.
2. Guard memcmp from accessing peripheral registers:
This only happens when a user decided to change kernel load address
to 256m or higher address. Since this is a quite unusual case, we
just skip 512m testing and return 256m as memory size.
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
[Minor commit message reword, make mt7621_memory_detect static]
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.