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>

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

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.

arch/powerpc/kernel/idle_64.c → 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
@@ -29,65 +33,62 @@
 #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.
 				 */
 				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

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
 

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

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)

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");
 }

arch/powerpc/platforms/maple/setup.c

@@ -290,7 +290,7 @@ struct machdep_calls __initdata maple_md = {
        	.get_rtc_time		= maple_get_rtc_time,
       	.calibrate_decr		= generic_calibrate_decr,
 	.progress		= maple_progress,
-	.idle_loop		= native_idle,
+	.power_save		= power4_idle,
 #ifdef CONFIG_KEXEC
 	.machine_kexec		= default_machine_kexec,
 	.machine_kexec_prepare	= default_machine_kexec_prepare,

arch/powerpc/platforms/powermac/setup.c

@@ -733,7 +733,7 @@ struct machdep_calls __initdata pmac_md = {
 	.progress		= udbg_progress,
 #ifdef CONFIG_PPC64
 	.pci_probe_mode		= pmac_pci_probe_mode,
-	.idle_loop		= native_idle,
+	.power_save		= power4_idle,
 	.enable_pmcs		= power4_enable_pmcs,
 #ifdef CONFIG_KEXEC
 	.machine_kexec		= default_machine_kexec,

arch/ppc/Makefile

@@ -59,8 +59,6 @@ head-$(CONFIG_4xx)		:= arch/ppc/kernel/head_4xx.o
 head-$(CONFIG_44x)		:= arch/ppc/kernel/head_44x.o
 head-$(CONFIG_FSL_BOOKE)	:= arch/ppc/kernel/head_fsl_booke.o
 
-head-$(CONFIG_6xx)		+= arch/ppc/kernel/idle_6xx.o
-head-$(CONFIG_POWER4)		+= arch/ppc/kernel/idle_power4.o
 head-$(CONFIG_PPC_FPU)		+= arch/powerpc/kernel/fpu.o
 
 core-y				+= arch/ppc/kernel/ arch/powerpc/kernel/ \

arch/ppc/kernel/Makefile

@@ -8,10 +8,9 @@ extra-$(CONFIG_40x)		:= head_4xx.o
 extra-$(CONFIG_44x)		:= head_44x.o
 extra-$(CONFIG_FSL_BOOKE)	:= head_fsl_booke.o
 extra-$(CONFIG_8xx)		:= head_8xx.o
-extra-$(CONFIG_6xx)		+= idle_6xx.o
 extra-y				+= vmlinux.lds
 
-obj-y				:= entry.o traps.o idle.o time.o misc.o \
+obj-y				:= entry.o traps.o time.o misc.o \
 					setup.o \
 					ppc_htab.o
 obj-$(CONFIG_6xx)		+= l2cr.o cpu_setup_6xx.o
@@ -35,7 +34,6 @@ endif
 # These are here while we do the architecture merge
 
 else
-obj-y				:= idle.o
 obj-$(CONFIG_6xx)		+= l2cr.o cpu_setup_6xx.o
 obj-$(CONFIG_SOFTWARE_SUSPEND)	+= swsusp.o
 obj-$(CONFIG_MODULES)		+= module.o

arch/ppc/kernel/entry.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.