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>

3 files changed, 53 insertions, 21 deletions

diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index b62de43ae5f3..d660dc36831a 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -450,6 +450,7 @@ enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
 
 extern int powersave_nap;       /* set if nap mode can be used in idle loop */
 extern void power7_nap(void);
+extern void power7_sleep(void);
 extern void flush_instruction_cache(void);
 extern void hard_reset_now(void);
 extern void poweroff_now(void);
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 38d507306a11..b01a9cb441e4 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -121,9 +121,10 @@ BEGIN_FTR_SECTION
         cmpwi   cr1,r13,2
         /* Total loss of HV state is fatal, we could try to use the
          * PIR to locate a PACA, then use an emergency stack etc...
-         * but for now, let's just stay stuck here
+         * OPAL v3 based powernv platforms have new idle states
+         * which fall in this catagory.
          */
-        bgt     cr1,.
+        bgt     cr1,8f
         GET_PACA(r13)
 
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
@@ -141,6 +142,11 @@ BEGIN_FTR_SECTION
         beq     cr1,2f
         b       .power7_wakeup_noloss
 2:      b       .power7_wakeup_loss
+
+        /* Fast Sleep wakeup on PowerNV */
+8:      GET_PACA(r13)
+        b       .power7_wakeup_loss
+
 9:
 END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
 #endif /* CONFIG_PPC_P7_NAP */
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)