powerpc: Unify the 32 and 64 bit idle loops

This unifies the 32-bit (ARCH=ppc and ARCH=powerpc) and 64-bit idle
loops.  It brings over the concept of having a ppc_md.power_save
function from 32-bit to ARCH=powerpc, which lets us get rid of
native_idle().  With this we will also be able to simplify the idle
handling for pSeries and cell.

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

7 files changed, 52 insertions, 84 deletions

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 80e9fe2632b8..f2c47e907037 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -12,12 +12,12 @@ endif
 
 obj-y                           := semaphore.o cputable.o ptrace.o syscalls.o \
                                    irq.o align.o signal_32.o pmc.o vdso.o \
-                                   init_task.o process.o systbl.o
+                                   init_task.o process.o systbl.o idle.o
 obj-y                           += vdso32/
 obj-$(CONFIG_PPC64)             += setup_64.o binfmt_elf32.o sys_ppc32.o \
                                    signal_64.o ptrace32.o \
                                    paca.o cpu_setup_power4.o \
-                                   firmware.o sysfs.o idle_64.o
+                                   firmware.o sysfs.o
 obj-$(CONFIG_PPC64)             += vdso64/
 obj-$(CONFIG_ALTIVEC)           += vecemu.o vector.o
 obj-$(CONFIG_POWER4)            += idle_power4.o
@@ -34,6 +34,7 @@ obj-$(CONFIG_IBMEBUS)           += ibmebus.o
 obj-$(CONFIG_GENERIC_TBSYNC)    += smp-tbsync.o
 obj64-$(CONFIG_PPC_MULTIPLATFORM) += nvram_64.o
 obj-$(CONFIG_CRASH_DUMP)        += crash_dump.o
+obj-$(CONFIG_6xx)               += idle_6xx.o
 
 ifeq ($(CONFIG_PPC_MERGE),y)
 
@@ -51,7 +52,6 @@ obj-$(CONFIG_PPC64)		+= misc_64.o dma_64.o iommu.o
 obj-$(CONFIG_PPC_MULTIPLATFORM) += prom_init.o
 obj-$(CONFIG_MODULES)           += ppc_ksyms.o
 obj-$(CONFIG_BOOTX_TEXT)        += btext.o
-obj-$(CONFIG_6xx)               += idle_6xx.o
 obj-$(CONFIG_SMP)               += smp.o
 obj-$(CONFIG_KPROBES)           += kprobes.o
 obj-$(CONFIG_PPC_UDBG_16550)    += legacy_serial.o udbg_16550.o
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 4827ca1ec89b..b3a979467225 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -135,10 +135,10 @@ transfer_to_handler:
         mfspr   r11,SPRN_HID0
         mtcr    r11
 BEGIN_FTR_SECTION
-        bt-     8,power_save_6xx_restore        /* Check DOZE */
+        bt-     8,4f                    /* Check DOZE */
 END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE)
 BEGIN_FTR_SECTION
-        bt-     9,power_save_6xx_restore        /* Check NAP */
+        bt-     9,4f                    /* Check NAP */
 END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
 #endif /* CONFIG_6xx */
         .globl transfer_to_handler_cont
@@ -157,6 +157,10 @@ transfer_to_handler_cont:
         SYNC
         RFI                             /* jump to handler, enable MMU */
 
+#ifdef CONFIG_6xx       
+4:      b       power_save_6xx_restore
+#endif
+
 /*
  * On kernel stack overflow, load up an initial stack pointer
  * and call StackOverflow(regs), which should not return.
diff --git a/arch/powerpc/kernel/idle_64.c b/arch/powerpc/kernel/idle.c
index b879d3057ef8..e9f321d74d85 100644
--- a/arch/powerpc/kernel/idle_64.c
+++ b/arch/powerpc/kernel/idle.c
@@ -2,13 +2,17 @@
  * Idle daemon for PowerPC.  Idle daemon will handle any action
  * that needs to be taken when the system becomes idle.
  *
- * Originally Written by Cort Dougan (cort@cs.nmt.edu)
+ * Originally written by Cort Dougan (cort@cs.nmt.edu).
+ * Subsequent 32-bit hacking by Tom Rini, Armin Kuster,
+ * Paul Mackerras and others.
  *
  * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
  *
  * Additional shared processor, SMT, and firmware support
  *    Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
  *
+ * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org>
+ *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version
@@ -29,18 +33,43 @@
 #include <asm/machdep.h>
 #include <asm/smp.h>
 
-extern void power4_idle(void);
+#ifdef CONFIG_HOTPLUG_CPU
+#define cpu_should_die()        (cpu_is_offline(smp_processor_id()) && \
+                                 system_state == SYSTEM_RUNNING)
+#else
+#define cpu_should_die()        0
+#endif
 
-void default_idle(void)
+/*
+ * The body of the idle task.
+ */
+void cpu_idle(void)
 {
-        unsigned int cpu = smp_processor_id();
-        set_thread_flag(TIF_POLLING_NRFLAG);
+        if (ppc_md.idle_loop)
+                ppc_md.idle_loop();     /* doesn't return */
 
+        set_thread_flag(TIF_POLLING_NRFLAG);
         while (1) {
-                if (!need_resched()) {
-                        while (!need_resched() && !cpu_is_offline(cpu)) {
-                                ppc64_runlatch_off();
+                ppc64_runlatch_off();
 
+                while (!need_resched() && !cpu_should_die()) {
+                        if (ppc_md.power_save) {
+                                clear_thread_flag(TIF_POLLING_NRFLAG);
+                                /*
+                                 * smp_mb is so clearing of TIF_POLLING_NRFLAG
+                                 * is ordered w.r.t. need_resched() test.
+                                 */
+                                smp_mb();
+                                local_irq_disable();
+
+                                /* check again after disabling irqs */
+                                if (!need_resched() && !cpu_should_die())
+                                        ppc_md.power_save();
+
+                                local_irq_enable();
+                                set_thread_flag(TIF_POLLING_NRFLAG);
+
+                        } else {
                                 /*
                                  * Go into low thread priority and possibly
                                  * low power mode.
@@ -48,46 +77,18 @@ void default_idle(void)
                                 HMT_low();
                                 HMT_very_low();
                         }
-
-                        HMT_medium();
                 }
 
+                HMT_medium();
                 ppc64_runlatch_on();
+                if (cpu_should_die())
+                        cpu_die();
                 preempt_enable_no_resched();
                 schedule();
                 preempt_disable();
-                if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
-                        cpu_die();
         }
 }
 
-void native_idle(void)
-{
-        while (1) {
-                ppc64_runlatch_off();
-
-                if (!need_resched())
-                        power4_idle();
-
-                if (need_resched()) {
-                        ppc64_runlatch_on();
-                        preempt_enable_no_resched();
-                        schedule();
-                        preempt_disable();
-                }
-
-                if (cpu_is_offline(smp_processor_id()) &&
-                    system_state == SYSTEM_RUNNING)
-                        cpu_die();
-        }
-}
-
-void cpu_idle(void)
-{
-        BUG_ON(NULL == ppc_md.idle_loop);
-        ppc_md.idle_loop();
-}
-
 int powersave_nap;
 
 #ifdef CONFIG_SYSCTL
diff --git a/arch/powerpc/kernel/idle_6xx.S b/arch/powerpc/kernel/idle_6xx.S
index 444fdcc769f1..1647ea361ef7 100644
--- a/arch/powerpc/kernel/idle_6xx.S
+++ b/arch/powerpc/kernel/idle_6xx.S
@@ -87,19 +87,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
         cmpwi   0,r3,0
         beqlr
 
-        /* Clear MSR:EE */
-        mfmsr   r7
-        rlwinm  r0,r7,0,17,15
-        mtmsr   r0
-
-        /* Check current_thread_info()->flags */
-        rlwinm  r4,r1,0,0,18
-        lwz     r4,TI_FLAGS(r4)
-        andi.   r0,r4,_TIF_NEED_RESCHED
-        beq     1f
-        mtmsr   r7      /* out of line this ? */
-        blr
-1:      
         /* Some pre-nap cleanups needed on some CPUs */
         andis.  r0,r3,HID0_NAP@h
         beq     2f
@@ -220,8 +207,6 @@ _GLOBAL(nap_save_msscr0)
 _GLOBAL(nap_save_hid1)
         .space  4*NR_CPUS
 
-_GLOBAL(powersave_nap)
-        .long   0
 _GLOBAL(powersave_lowspeed)
         .long   0
 
diff --git a/arch/powerpc/kernel/idle_power4.S b/arch/powerpc/kernel/idle_power4.S
index c16b4afab582..692cf2ebe0f4 100644
--- a/arch/powerpc/kernel/idle_power4.S
+++ b/arch/powerpc/kernel/idle_power4.S
@@ -49,21 +49,6 @@ END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP)
         cmpwi   0,r4,0
         beqlr
 
-        /* Clear MSR:EE */
-        mfmsr   r7
-        li      r4,0
-        ori     r4,r4,MSR_EE
-        andc    r0,r7,r4
-        mtmsrd  r0
-
-        /* Check current_thread_info()->flags */
-        clrrdi  r4,r1,THREAD_SHIFT
-        ld      r4,TI_FLAGS(r4)
-        andi.   r0,r4,_TIF_NEED_RESCHED
-        beq     1f
-        mtmsrd  r7      /* out of line this ? */
-        blr
-1:
         /* Go to NAP now */
 BEGIN_FTR_SECTION
         DSSALL
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 676f894c3380..e39f830317a8 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -53,9 +53,6 @@
 extern void platform_init(void);
 extern void bootx_init(unsigned long r4, unsigned long phys);
 
-extern void ppc6xx_idle(void);
-extern void power4_idle(void);
-
 boot_infos_t *boot_infos;
 struct ide_machdep_calls ppc_ide_md;
 
@@ -194,7 +191,9 @@ void __init machine_init(unsigned long dt_ptr, unsigned long phys)
         platform_init();
 
 #ifdef CONFIG_6xx
-        ppc_md.power_save = ppc6xx_idle;
+        if (cpu_has_feature(CPU_FTR_CAN_DOZE) ||
+            cpu_has_feature(CPU_FTR_CAN_NAP))
+                ppc_md.power_save = ppc6xx_idle;
 #endif
 
         if (ppc_md.progress)
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 6c9b093c23a5..5b63a861ef43 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -607,12 +607,6 @@ void __init setup_arch(char **cmdline_p)
 
         ppc_md.setup_arch();
 
-        /* Use the default idle loop if the platform hasn't provided one. */
-        if (NULL == ppc_md.idle_loop) {
-                ppc_md.idle_loop = default_idle;
-                printk(KERN_INFO "Using default idle loop\n");
-        }
-
         paging_init();
         ppc64_boot_msg(0x15, "Setup Done");
 }