powerpc/powernv: Add context management for Fast Sleep

Before adding Fast-Sleep into the cpuidle framework, some low level
support needs to be added to enable it. This includes saving and
restoring of certain registers at entry and exit time of this state
respectively just like we do in the NAP idle state.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
[Changelog modified by Preeti U. Murthy <preeti@linux.vnet.ibm.com>]
Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 44 insertions, 19 deletions

diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S
index 3fdef0f0c67f..14f78bec62c4 100644
--- a/arch/powerpc/kernel/idle_power7.S
+++ b/arch/powerpc/kernel/idle_power7.S
@@ -20,17 +20,27 @@
 
 #undef DEBUG
 
-        .text
+/* Idle state entry routines */
 
-_GLOBAL(power7_idle)
-        /* Now check if user or arch enabled NAP mode */
-        LOAD_REG_ADDRBASE(r3,powersave_nap)
-        lwz     r4,ADDROFF(powersave_nap)(r3)
-        cmpwi   0,r4,0
-        beqlr
-        /* fall through */
+#define IDLE_STATE_ENTER_SEQ(IDLE_INST)                         \
+        /* Magic NAP/SLEEP/WINKLE mode enter sequence */        \
+        std     r0,0(r1);                                       \
+        ptesync;                                                \
+        ld      r0,0(r1);                                       \
+1:      cmp     cr0,r0,r0;                                      \
+        bne     1b;                                             \
+        IDLE_INST;                                              \
+        b       .
 
-_GLOBAL(power7_nap)
+        .text
+
+/*
+ * Pass requested state in r3:
+ *      0 - nap
+ *      1 - sleep
+ */
+_GLOBAL(power7_powersave_common)
+        /* Use r3 to pass state nap/sleep/winkle */
         /* NAP is a state loss, we create a regs frame on the
          * stack, fill it up with the state we care about and
          * stick a pointer to it in PACAR1. We really only
@@ -79,8 +89,8 @@ _GLOBAL(power7_nap)
         /* Continue saving state */
         SAVE_GPR(2, r1)
         SAVE_NVGPRS(r1)
-        mfcr    r3
-        std     r3,_CCR(r1)
+        mfcr    r4
+        std     r4,_CCR(r1)
         std     r9,_MSR(r1)
         std     r1,PACAR1(r13)
 
@@ -90,15 +100,30 @@ _GLOBAL(power7_enter_nap_mode)
         li      r4,KVM_HWTHREAD_IN_NAP
         stb     r4,HSTATE_HWTHREAD_STATE(r13)
 #endif
+        cmpwi   cr0,r3,1
+        beq     2f
+        IDLE_STATE_ENTER_SEQ(PPC_NAP)
+        /* No return */
+2:      IDLE_STATE_ENTER_SEQ(PPC_SLEEP)
+        /* No return */
 
-        /* Magic NAP mode enter sequence */
-        std     r0,0(r1)
-        ptesync
-        ld      r0,0(r1)
-1:      cmp     cr0,r0,r0
-        bne     1b
-        PPC_NAP
-        b       .
+_GLOBAL(power7_idle)
+        /* Now check if user or arch enabled NAP mode */
+        LOAD_REG_ADDRBASE(r3,powersave_nap)
+        lwz     r4,ADDROFF(powersave_nap)(r3)
+        cmpwi   0,r4,0
+        beqlr
+        /* fall through */
+
+_GLOBAL(power7_nap)
+        li      r3,0
+        b       power7_powersave_common
+        /* No return */
+
+_GLOBAL(power7_sleep)
+        li      r3,1
+        b       power7_powersave_common
+        /* No return */
 
 _GLOBAL(power7_wakeup_loss)
         ld      r1,PACAR1(r13)