powerpc: Fix goof in 6xx and POWER4 idle power-save functions

This fixes a mistake I made when editing these functions - when I
took out the interrupt disabling code (because interrupts are now
disabled by the caller) I left the register that is used for the MSR
value to be used during doze/nap uninitialized.  This fixes it.

Also updated some of the comments in idle_power4.S and removed some
code that was copied over from idle_6xx.S but is no longer relevant
(we don't ever clear the CPU_FTR_CAN_NAP bit at runtime for POWER4).

Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 5 insertions, 21 deletions

diff --git a/arch/powerpc/kernel/idle_6xx.S b/arch/powerpc/kernel/idle_6xx.S
index 1647ea361ef7..12a4efbaa08f 100644
--- a/arch/powerpc/kernel/idle_6xx.S
+++ b/arch/powerpc/kernel/idle_6xx.S
@@ -144,7 +144,8 @@ BEGIN_FTR_SECTION
         DSSALL
         sync
 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
-        ori     r7,r7,MSR_EE /* Could be ommited (already set) */
+        mfmsr   r7
+        ori     r7,r7,MSR_EE
         oris    r7,r7,MSR_POW@h
         sync
         isync
diff --git a/arch/powerpc/kernel/idle_power4.S b/arch/powerpc/kernel/idle_power4.S
index 692cf2ebe0f4..6dad1c02496e 100644
--- a/arch/powerpc/kernel/idle_power4.S
+++ b/arch/powerpc/kernel/idle_power4.S
@@ -1,11 +1,5 @@
 /*
- *  This file contains the power_save function for 6xx & 7xxx CPUs
- *  rewritten in assembler
- *
- *  Warning ! This code assumes that if your machine has a 750fx
- *  it will have PLL 1 set to low speed mode (used during NAP/DOZE).
- *  if this is not the case some additional changes will have to
- *  be done to check a runtime var (a bit like powersave-nap)
+ *  This file contains the power_save function for 970-family CPUs.
  *
  *  This program is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU General Public License
@@ -26,23 +20,10 @@
 
         .text
 
-/*
- * Here is the power_save_6xx function. This could eventually be
- * split into several functions & changing the function pointer
- * depending on the various features.
- */
 _GLOBAL(power4_idle)
 BEGIN_FTR_SECTION
         blr
 END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP)
-        /* We must dynamically check for the NAP feature as it
-         * can be cleared by CPU init after the fixups are done
-         */
-        LOAD_REG_ADDRBASE(r3,cur_cpu_spec)
-        ld      r4,ADDROFF(cur_cpu_spec)(r3)
-        ld      r4,CPU_SPEC_FEATURES(r4)
-        andi.   r0,r4,CPU_FTR_CAN_NAP
-        beqlr
         /* Now check if user or arch enabled NAP mode */
         LOAD_REG_ADDRBASE(r3,powersave_nap)
         lwz     r4,ADDROFF(powersave_nap)(r3)
@@ -54,6 +35,8 @@ BEGIN_FTR_SECTION
         DSSALL
         sync
 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
+        mfmsr   r7
+        ori     r7,r7,MSR_EE
         oris    r7,r7,MSR_POW@h
         sync
         isync