powerpc/powernv: Enable Offline CPUs to enter deep idle states

The secondary threads should enter deep idle states so as to gain maximum
powersavings when the entire core is offline. To do so the offline path
must be made aware of the available deepest idle state. Hence probe the
device tree for the possible idle states in powernv core code and
expose the deepest idle state through flags.

Since the  device tree is probed by the cpuidle driver as well, move
the parameters required to discover the idle states into an appropriate
common place to both the driver and the powernv core code.

Another point is that fastsleep idle state may require workarounds in
the kernel to function properly. This workaround is introduced in the
subsequent patches. However neither the cpuidle driver or the hotplug
path need be bothered about this workaround.

They will be taken care of by the core powernv code.

Originally-by: Srivatsa S. Bhat <srivatsa@mit.edu>
Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Reviewed-by: Paul Mackerras <paulus@samba.org>

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 3 insertions, 6 deletions

diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 7d3a3497dd4c..0a7d827897e4 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -16,13 +16,10 @@
 
 #include <asm/machdep.h>
 #include <asm/firmware.h>
+#include <asm/opal.h>
 #include <asm/runlatch.h>
 
-/* Flags and constants used in PowerNV platform */
-
 #define MAX_POWERNV_IDLE_STATES 8
-#define IDLE_USE_INST_NAP       0x00010000 /* Use nap instruction */
-#define IDLE_USE_INST_SLEEP     0x00020000 /* Use sleep instruction */
 
 struct cpuidle_driver powernv_idle_driver = {
         .name             = "powernv_idle",
@@ -198,7 +195,7 @@ static int powernv_add_idle_states(void)
                  * target residency to be 10x exit_latency
                  */
                 latency_ns = be32_to_cpu(idle_state_latency[i]);
-                if (flags & IDLE_USE_INST_NAP) {
+                if (flags & OPAL_PM_NAP_ENABLED) {
                         /* Add NAP state */
                         strcpy(powernv_states[nr_idle_states].name, "Nap");
                         strcpy(powernv_states[nr_idle_states].desc, "Nap");
@@ -211,7 +208,7 @@ static int powernv_add_idle_states(void)
                         nr_idle_states++;
                 }
 
-                if (flags & IDLE_USE_INST_SLEEP) {
+                if (flags & OPAL_PM_SLEEP_ENABLED) {
                         /* Add FASTSLEEP state */
                         strcpy(powernv_states[nr_idle_states].name, "FastSleep");
                         strcpy(powernv_states[nr_idle_states].desc, "FastSleep");