775fa495af
There are a couple subtle errors in the mapping between cpu-ids and a cpus associated drc-index when using the new ibm,drc-info property. The first is that while drc-info may have been a supported firmware feature at boot it is possible we have migrated to a CEC with older firmware that doesn't support the ibm,drc-info property. In that case the device tree would have been updated after migration to remove the ibm,drc-info property and replace it with the older style ibm,drc-* properties for types, indexes, names, and power-domains. PAPR even goes as far as dictating that if we advertise support for drc-info that we are capable of supporting either property type at runtime. The second is that the first value of the ibm,drc-info property is the int encoded count of drc-info entries. As such "value" returned by of_prop_next_u32() is pointing at that count, and not the first element of the first drc-info entry as is expected by the of_read_drc_info_cell() helper. Fix the first by ignoring DRC-INFO firmware feature and instead testing directly for ibm,drc-info, and then falling back to the old style ibm,drc-indexes in the case it doesn't exit. Fix the second by incrementing value to the next element prior to parsing drc-info entries. Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1573449697-5448-3-git-send-email-tyreld@linux.ibm.com
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.