ARM: OMAP4: PM: Add CPUidle support

Add OMAP4 CPUIDLE support. CPU1 is left with defualt idle and
the low power state for it is managed via cpu-hotplug.

This patch adds MPUSS low power states in cpuidle.

	C1 - CPU0 ON + CPU1 ON + MPU ON
	C2 - CPU0 OFF + CPU1 OFF + MPU CSWR
	C3 - CPU0 OFF + CPU1 OFF + MPU OSWR

OMAP4460 onwards, MPUSS power domain doesn't support OFF state any more
anymore just like CORE power domain. The deepest state supported is OSWr.
Ofcourse when MPUSS and CORE PD transitions to OSWR along with device
off mode, even the memory contemts are lost which is as good as
the PD off state.

On OMAP4 because of hardware constraints, no low power states are
targeted when both CPUs are online and in SMP mode. The low power
states are attempted only when secondary CPU gets offline to OFF
through hotplug infrastructure.

Thanks to Nicole Chalhoub <n-chalhoub@ti.com> for doing exhaustive
C-state latency profiling.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
index 4e166add2f35..b737b11e4499 100644
--- a/arch/arm/mach-omap2/pm.h
+++ b/arch/arm/mach-omap2/pm.h
@@ -21,6 +21,7 @@ extern void omap_sram_idle(void);
 extern int omap3_can_sleep(void);
 extern int omap_set_pwrdm_state(struct powerdomain *pwrdm, u32 state);
 extern int omap3_idle_init(void);
+extern int omap4_idle_init(void);
 
 #if defined(CONFIG_PM_OPP)
 extern int omap3_opp_init(void);