62f6260f70
[ Upstream commit 9f4873fb6af7966de8fcbd95c36b61351c1c4b1f ]
AMD Rome systems and later support interleaving between three identical
ranks within a channel.
Check for this mode by counting the number of enabled chip selects and
comparing their masks. If there are exactly three enabled chip selects
and their masks are identical, then three rank interleaving is enabled.
The size of a rank is determined from its mask value. However, three
rank interleaving doesn't follow the method of swapping an interleave
bit with the most significant bit. Rather, the interleave bit is flipped
and the most significant bit remains the same. There is only a single
interleave bit in this case.
Account for this when determining the chip select size by keeping the
most significant bit at its original value and ignoring any zero bits.
This will return a full bitmask in [MSB:1].
Fixes: e53a3b267fb0 ("EDAC/amd64: Find Chip Select memory size using Address Mask")
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211005154419.2060504-1-yazen.ghannam@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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.