cpufreq: Retain only online cpus in managed_policy->cpus

cpufreq's handling of cpu online event can incorrectly initialize
managed_policy->cpus to include offline cpus. This causes cpufreq
governors to include offline cpus in their idle time computation, which
causes frequency to shoot up beyond normal levels (on systems where 2 or
more cpus need to be synchronized wrt frequency change).

This frequency shootup was not seen prior to commit 21111be8 which
changed idle time accounting for offline cpus. Prior to commit 21111be8,
idle time statistics for offline cpus would include their offline time
as well. Post commit 21111be8, offline time is not included in a cpu's
idle time statistics.

As a result, ondemand (or other cpufreq) governors would see unchanged
idle time for offline cpus, causing them to interpret those (offline)
cpus as 100% busy, which is wrong.

This patch fixes the issue by modifying cpufreq's hotplug handling to
retain only online cpus in managed_policy->cpus field. cpufreq governors
would then skip such offline cpus from idle time calculations.

Change-Id: Id2eba8c0ec3367609369b2e42a4e1386ff2e7ab5
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
cpufreq: Resolve CPUFREQ_NOTIFY issue

When the cpufreq_stat receives the frequency policy notification,
it checks if the frequency table and stats table are present for the cpu.
If both are present, it returns with -EBUSY error to the notification.
Due to this, none of the other registered modules receive this
notification.

If the stat table and sysfs nodes are already created, return 0 instead
of returning EBUSY error.

Change-Id: I1fd4a46e6a65edfc6253c4271288f10912ae2ad7
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
msm: rq_stats: Fix missing initalization of cur_freq

Initialize cur_freq variable of each online cpu to the current
running cpu clock frequency. This avoids zeroing out the load
calculations until the first notification of the change in CPU
frequency comes in after CPUFREQ governors are intialized.

Also when a non boot cpu is up, update its cur_freq variable.

(cherry picked from commit 1633a48b16614e6b85c047a19ec93867c2ced3b3)

Change-Id: I950686deff02e2339eefae7d09392dda2174a545
CRs-fixed: 446017
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>

Conflicts:
	arch/arm/mach-msm/msm_rq_stats.c
msm:rq_stats: Add hotplug disable attribute

Register for suspend and resume notifications from kernel. This should
be done as part of core_initcall so as to receive notification as close
as possible to the actual event. Add hotplug_disable attribute to
rq-stats node. Set/clear this attribute based on the suspend/resume events.

CRS-fixed: 452456
Change-Id: I76fee349b57f47df40785e9c2503e2e1cc6e064e
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
msm:rq_stats: Fix hotplug attribute during the suspend failure

If the system suspend fails, the hotplug_disable attribute remains
set. This prevents any change to core status from mpdecision. Reset
the value of this attribute if the module receives PM_POST_RESTORE
notification.

Change-Id: I22fd639134adbeb8f8f96603e285151480f537ec
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
msm:rq_stats: Register for Cpufreq policy notification

Currently the load of the system is calculated using the max
frequency that is read during startup(It does not get updated
when the policy changes). As a result, the average load of the
system is incorrectly calculated and the system might not bring
the cpus online to manage the additional load. This
reduces the performance of the system.

To fix this issue, register rq_stats to receive cpufreq policy
notifications. Update the policy's max frequency when a
notification is received and use that value to calculate the load.

Change-Id: Icc78e28c736c170e198f723fd96c13dfb2dafe8a
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>