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dc279ac6e5
cpufreq-dt is currently unable to handle -EPROBE_DEFER properly
because the error code is not propagated for the cpufreq_driver->init()
callback. Instead, it attempts to avoid the situation by temporarily
requesting all resources within resources_available() and releasing them
again immediately after. This has several disadvantages:
- Whenever we add something like interconnect handling to the OPP core
we need to patch cpufreq-dt to request these resources early.
- resources_available() is only run for CPU0, but other clusters may
eventually depend on other resources that are not available yet.
(See FIXME comment removed by this commit...)
- All resources need to be looked up several times.
Now that the OPP core can propagate -EPROBE_DEFER during initialization,
it would be nice to avoid all that trouble and just propagate its error
code when necessary.
This commit refactors the cpufreq-dt driver to initialize private_data
before registering the cpufreq driver. We do this by iterating over
all possible CPUs and ensure that all resources are initialized:
1. dev_pm_opp_get_opp_table() ensures the OPP table is allocated
and initialized with clock and interconnects.
2. dev_pm_opp_set_regulators() requests the regulators and assigns
them to the OPP table.
3. We call dev_pm_opp_of_get_sharing_cpus() early so that we only
initialize the OPP table once for each shared policy.
With these changes, we actually end up saving a few lines of code,
the resources are no longer looked up multiple times and everything
should be much more robust.
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
[ Viresh: Use list_head structure for maintaining the list and minor
changes ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.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.