sched/idle, PPC: Remove redundant cpuidle_idle_call()

The core idle loop now takes care of it.  However a few things need
checking:

- Invocation of cpuidle_idle_call() in pseries_lpar_idle() happened
  through arch_cpu_idle() and was therefore always preceded by a call
  to ppc64_runlatch_off().  To preserve this property now that
  cpuidle_idle_call() is invoked directly from core code, a call to
  ppc64_runlatch_off() has been added to idle_loop_prolog() in
  platforms/pseries/processor_idle.c.

- Similarly, cpuidle_idle_call() was followed by ppc64_runlatch_off()
  so a call to the later has been added to idle_loop_epilog().

- And since arch_cpu_idle() always made sure to re-enable IRQs if they
  were not enabled, this is now
  done in idle_loop_epilog() as well.

The above was made in order to keep the execution flow close to the
original.  I don't know if that was strictly necessary. Someone well
aquainted with the platform details might find some room for possible
optimizations.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-sh@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linaro-kernel@lists.linaro.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-47o4m03citrfg9y1vxic5asb@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 14 insertions, 20 deletions

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 8e639d7cbda7..c737d554571a 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -39,7 +39,6 @@
 #include <linux/irq.h>
 #include <linux/seq_file.h>
 #include <linux/root_dev.h>
-#include <linux/cpuidle.h>
 #include <linux/of.h>
 #include <linux/kexec.h>
 
@@ -356,29 +355,24 @@ early_initcall(alloc_dispatch_log_kmem_cache);
 
 static void pseries_lpar_idle(void)
 {
-        /* This would call on the cpuidle framework, and the back-end pseries
-         * driver to  go to idle states
+        /*
+         * Default handler to go into low thread priority and possibly
+         * low power mode by cedeing processor to hypervisor
          */
-        if (cpuidle_idle_call()) {
-                /* On error, execute default handler
-                 * to go into low thread priority and possibly
-                 * low power mode by cedeing processor to hypervisor
-                 */
 
-                /* Indicate to hypervisor that we are idle. */
-                get_lppaca()->idle = 1;
+        /* Indicate to hypervisor that we are idle. */
+        get_lppaca()->idle = 1;
 
-                /*
-                 * Yield the processor to the hypervisor.  We return if
-                 * an external interrupt occurs (which are driven prior
-                 * to returning here) or if a prod occurs from another
-                 * processor. When returning here, external interrupts
-                 * are enabled.
-                 */
-                cede_processor();
+        /*
+         * Yield the processor to the hypervisor.  We return if
+         * an external interrupt occurs (which are driven prior
+         * to returning here) or if a prod occurs from another
+         * processor. When returning here, external interrupts
+         * are enabled.
+         */
+        cede_processor();
 
-                get_lppaca()->idle = 0;
-        }
+        get_lppaca()->idle = 0;
 }
 
 /*