ARM: OMAP4: PM: Avoid expensive cpu_suspend() path for all CPU power states except off

Current CPU PM code code make use of common cpu_suspend() path for all the
CPU power states which is not optimal. In fact cpu_suspend() path is needed
only when we put CPU power domain to off state where the CPU context is lost.

Update the code accordingly so that the expensive cpu_suspend() path
can be avoided for the shallow CPU power states like CPU PD INA/CSWR.

The patch has been tested on OMAP4430 and OMAP5430(with few out of tree patches)
devices for suspend and CPUidle.

Cc: Kevin Hilman <khilman@deeprootsystems.com>

Reported-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
index 8bcb64bcdcdb..d650f91f15de 100644
--- a/arch/arm/mach-omap2/omap-mpuss-lowpower.c
+++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
@@ -246,7 +246,10 @@ int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
         /*
          * Call low level function  with targeted low power state.
          */
-        cpu_suspend(save_state, omap4_finish_suspend);
+        if (save_state)
+                cpu_suspend(save_state, omap4_finish_suspend);
+        else
+                omap4_finish_suspend(save_state);
 
         /*
          * Restore the CPUx power state to ON otherwise CPUx