linux/drivers/cpufreq/Kconfig.powerpc
Vaidyanathan Srinivasan b3d627a5f2 cpufreq: powernv: cpufreq driver for powernv platform
Backend driver to dynamically set voltage and frequency on
IBM POWER non-virtualized platforms.  Power management SPRs
are used to set the required PState.

This driver works in conjunction with cpufreq governors
like 'ondemand' to provide a demand based frequency and
voltage setting on IBM POWER non-virtualized platforms.

PState table is obtained from OPAL v3 firmware through device
tree.

powernv_cpufreq back-end driver would parse the relevant device-tree
nodes and initialise the cpufreq subsystem on powernv platform.

The code was originally written by svaidy@linux.vnet.ibm.com. Over
time it was modified to accomodate bug-fixes as well as updates to the
the cpu-freq core. Relevant portions of the change logs corresponding
to those modifications are noted below:

 * The policy->cpus needs to be populated in a hotplug-invariant
   manner instead of using cpu_sibling_mask() which varies with
   cpu-hotplug. This is because the cpufreq core code copies this
   content into policy->related_cpus mask which should not vary on
   cpu-hotplug. [Authored by srivatsa.bhat@linux.vnet.ibm.com]

 * Create a helper routine that can return the cpu-frequency for the
   corresponding pstate_id. Also, cache the values of the pstate_max,
   pstate_min and pstate_nominal and nr_pstates in a static structure
   so that they can be reused in the future to perform any
   validations. [Authored by ego@linux.vnet.ibm.com]

 * Create a driver attribute named cpuinfo_nominal_freq which creates
   a sysfs read-only file named cpuinfo_nominal_freq. Export the
   frequency corresponding to the nominal_pstate through this
   interface.

     Nominal frequency is the highest non-turbo frequency for the
   platform.  This is generally used for setting governor policies
   from user space for optimal energy efficiency. [Authored by
   ego@linux.vnet.ibm.com]

 * Implement a powernv_cpufreq_get(unsigned int cpu) method which will
   return the current operating frequency. Export this via the sysfs
   interface cpuinfo_cur_freq by setting powernv_cpufreq_driver.get to
   powernv_cpufreq_get(). [Authored by ego@linux.vnet.ibm.com]

[Change log updated by ego@linux.vnet.ibm.com]

Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-04-07 14:35:27 +02:00

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config CPU_FREQ_CBE
tristate "CBE frequency scaling"
depends on CBE_RAS && PPC_CELL
default m
help
This adds the cpufreq driver for Cell BE processors.
For details, take a look at <file:Documentation/cpu-freq/>.
If you don't have such processor, say N
config CPU_FREQ_CBE_PMI
bool "CBE frequency scaling using PMI interface"
depends on CPU_FREQ_CBE
default n
help
Select this, if you want to use the PMI interface to switch
frequencies. Using PMI, the processor will not only be able to run at
lower speed, but also at lower core voltage.
config CPU_FREQ_MAPLE
bool "Support for Maple 970FX Evaluation Board"
depends on PPC_MAPLE
help
This adds support for frequency switching on Maple 970FX
Evaluation Board and compatible boards (IBM JS2x blades).
config PPC_CORENET_CPUFREQ
tristate "CPU frequency scaling driver for Freescale E500MC SoCs"
depends on PPC_E500MC && OF && COMMON_CLK
select CLK_PPC_CORENET
help
This adds the CPUFreq driver support for Freescale e500mc,
e5500 and e6500 series SoCs which are capable of changing
the CPU's frequency dynamically.
config CPU_FREQ_PMAC
bool "Support for Apple PowerBooks"
depends on ADB_PMU && PPC32
help
This adds support for frequency switching on Apple PowerBooks,
this currently includes some models of iBook & Titanium
PowerBook.
config CPU_FREQ_PMAC64
bool "Support for some Apple G5s"
depends on PPC_PMAC && PPC64
help
This adds support for frequency switching on Apple iMac G5,
and some of the more recent desktop G5 machines as well.
config PPC_PASEMI_CPUFREQ
bool "Support for PA Semi PWRficient"
depends on PPC_PASEMI
default y
help
This adds the support for frequency switching on PA Semi
PWRficient processors.
config POWERNV_CPUFREQ
tristate "CPU frequency scaling for IBM POWERNV platform"
depends on PPC_POWERNV
default y
help
This adds support for CPU frequency switching on IBM POWERNV
platform