cpufreq: interactive: Fix handling of SMP where CPUs must scale in tandem

The interactive governor relies on quirks of the Tegra 2 cpufreq
implementation for handling SMP systems where the CPUs do not have
separate rate controls.  It needs to determine the maximum rate
for all CPUs covered by the policy and set that speed.

Change-Id: I1ed9fa171e5a9c45a1fa5944e3fa823eb157e81f
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive: fix possible Division by zero.

The following dump was seen sometimes while resuming,
the only division by zero on this function can happen after
delta_time is reassigned, since at the start of the
function, there is jump that protects against values
less than 1000.

After that, If delta_time and delta_idle == 0,
we will hit a div 0

Division by zero in kernel.
Backtrace:
[<c0057184>] (dump_backtrace+0x0/0x110) from [<c05d5ecc>] (dump_stack+0x18/0x1c)
r6:010f3000 r5:c113dfb0 r4:c004afb0 r3:c6ff0000
[<c05d5eb4>] (dump_stack+0x0/0x1c) from [<c00572cc>] (__div0+0x1c/0x20)
[<c00572b0>] (__div0+0x0/0x20) from [<c02195d4>] (Ldiv0+0x8/0x10)
[<c03dfd64>] (cpufreq_interactive_timer+0x0/0x2c0) from [<c00a7efc>] (run_timer_softirq+0x154/0x260)
[<c00a7da8>] (run_timer_softirq+0x0/0x260) from [<c00a0c8c>] (__do_softirq+0xc8/0x194)
[<c00a0bc4>] (__do_softirq+0x0/0x194) from [<c00a1008>] (irq_exit+0xb4/0xb8)
[<c00a0f54>] (irq_exit+0x0/0xb8) from [<c00584b4>] (ipi_timer+0x44/0x48)
r4:c004a040 r3:00000001
[<c0058470>] (ipi_timer+0x0/0x48) from [<c004c3e4>] (do_local_timer+0x68/0x84)
r5:c004ae2c r4:c07991e8
[<c004c37c>] (do_local_timer+0x0/0x84) from [<c0052948>] (__irq_svc+0x48/0xe0)

Change-Id: I639882db67b8d711c5710778ebc212f0f6a998e3

Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Axel Haslam <axelhaslam@ti.com>
cpufreq: interactive governor: default timer 10ms, maxspeed load 95%

Modify default timer from 30ms to 10ms, sampling 2 jiffies after
idle exit on ARM as in Honeycomb.

Modify default go_maxspeed_load from 85% loaded to 95% loaded, for
use in phones where power savings is more important (tablets may be
best served overriding this).

Change-Id: I3361a6279979bfae1df5262666a2e30ea7a44328
Signed-off-by: Todd Poynor <toddpoynor@google.com>
power: cpufreq interactive governor: use default sample time 20ms

Lower the default time at which a higher speed is allowed to run
before lowering based on lower CPU load from 80ms to 20ms.  Most
Android devices should trade power for performance here,
although tablets and non-battery-powered devices may want to
override this default.

Change-Id: I1a4f7faeca12793c51d5b92db30a63cca8d4f1be
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive governor: apply intermediate load on current speed

Calculate intermediate speed by applyng CPU load to current speed, not
max speed.

Change-Id: Idecf598b9a203b07c989c5d9e9c6efc67a1afc2e
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive governor: scale to max only if at min speed

Change-Id: Ieffb2aa56b5290036285c948718be7be0d3af9e8
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive governor: go to intermediate hi speed before max

* Add attribute hispeed_freq, which defaults to max.

* Rename go_maxspeed_load to go_hispeed_load.

* If hit go_hispeed_load and at min speed, go to hispeed_freq;
  if hit go_hispeed_load and already above min speed go to max
  speed.

Change-Id: I1050dec5f013fc1177387352ba787a7e1c68703e
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive governor: default 20ms timer

Change-Id: Ie9952f07b38667f2932474090044195c57976faa
Signed-off-by: Todd Poynor <toddpoynor@google.com>