Previous patch changed based on Christian Krafft's comment.

On some legacy SLOF tree the generic code is unable to ioremap some Cell BE
registers. Therefore the "generic" functions are returning a NULL pointer,
triggering a crash on such platforms.

Let's handle this more gracefully.
Signed-off-by: NJean-Christophe DUBOIS <jcd@tribudubois.net>
Acked-by: NChristian Kraff <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>

This patch reorganizes the code of the driver into three files.
Two cbe_cpufreq_pmi.c and cbe_cpufreq_pervasive.c care about hardware.
cbe_cpufreq.c contains the logic.
There is no changed behaviour, except that the PMI related function
is now located in a seperate module cbe_cpufreq_pmi. This module
will be required by cbe_cpufreq, if CONFIG_CBE_CPUFREQ_PMI has been set.
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>

Minor issues have been fixed:
* added a missing call to of_node_put()
* signedness of a function parameter
* added some line breaks
* changed global pmi_frequency_limit to a
  per node pmi_slow_mode_limit array
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>

This patch fixes the initialization of the cbe_cpufreq driver.
The code that initializes the PMI related functions was called per cpu:
* registering cpufreq notifier block
* registering a pmi handler

This ends in a bug that the notifier block gets called in an endless loop.
The initialization code is being put to the
module init code path by this patch. This way it only gets called once.
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>

This patch fixes the debug code that calculates the transition time when
changing the slow modes on a Cell BE cpu.
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>

The pmi driver got simplified by removing support for multiple devices.
As there is no more than one pmi device per maschine, there is no need to
specify the device for listening and sending messages.

This way the caller (cbe_cpufreq) doesn't need to scan the device tree.
When registering the handler on a board without a pmi
interface, pmi.c will just return -ENODEV.

The patch that fixed the breakage of cell_defconfig has been
broken out of the earlier version of this patch. So this is
the version that applies cleanly on top of it.
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>

The recent change to cell_defconfig to enable cpufreq on Cell exposed
the fact that the cbe_cpufreq driver currently needs the PMI interface
code to compile, but Kconfig doesn't make sure that the PMI interface
code gets built if cbe_cpufreq is enabled.

In fact cbe_cpufreq can work without PMI, so this ifdefs out the code
that deals with PMI.  This is a minimal solution for 2.6.22; a more
comprehensive solution will be merged for 2.6.23.
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

... and get rid of cpufreq_set_policy call that caused a build
failure due interfering commits.
Signed-off-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

cbe_cpufreq cleanups:

* comment format
* whitespace
* don't init on non-cell platforms
Signed-off-by: NOlof Johansson <olof@lixom.net>
Acked-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The new PMI driver was added in order to support
cpufreq on blades that require the frequency to
be controlled by the service processor, so use it
on those.
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>

This also fixes a bug where a property value was being modified
in place.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This patch adds a cpufreq backend driver to enable frequency scaling on cell.
Signed-off-by: NChristian Krafft <krafft@de.ibm.com>
Signed-off-by: NArnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>