Subject: [v6 PATCH 3/7]: x86: refactor x86 idle power management code and remove all instances of pm_idle.

From: Arun R Bharadwaj <[email-masked]>
Date: Tue, 22 Sep 2009 16:59:36 +0530

* Arun R Bharadwaj <[email-masked]> [2009-09-22 16:55:27]:

This patch cleans up x86 of all instances of pm_idle.

pm_idle which was earlier called from cpu_idle() idle loop
is replaced by cpuidle_idle_call.

x86 also registers to cpuidle when the idle routine is selected,
by populating the cpuidle_device data structure for each cpu.

This is replicated for apm module and for xen, which also used pm_idle.

Signed-off-by: Arun R Bharadwaj <[email-masked]>
---
 arch/x86/kernel/apm_32.c     |   37 +++++++++++++++++++++--
 arch/x86/kernel/process.c    |   69 ++++++++++++++++++++++++++++++++++---------
 arch/x86/kernel/process_32.c |    3 +
 arch/x86/kernel/process_64.c |    3 +
 arch/x86/xen/setup.c         |   22 +++++++++++++
 5 files changed, 114 insertions(+), 20 deletions(-)

Index: linux.trees.git/arch/x86/kernel/process.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/process.c
+++ linux.trees.git/arch/x86/kernel/process.c
@@ -9,6 +9,8 @@
 #include <linux/pm.h>
 #include <linux/clockchips.h>
 #include <linux/random.h>
+#include <linux/cpuidle.h>
+
 #include <trace/power.h>
 #include <asm/system.h>
 #include <asm/apic.h>
@@ -247,12 +249,6 @@ int sys_vfork(struct pt_regs *regs)
 unsigned long boot_option_idle_override = 0;
 EXPORT_SYMBOL(boot_option_idle_override);
 
-/*
- * Powermanagement idle function, if any..
- */
-void (*pm_idle)(void);
-EXPORT_SYMBOL(pm_idle);
-
 #ifdef CONFIG_X86_32
 /*
  * This halt magic was a workaround for ancient floppy DMA
@@ -531,15 +527,58 @@ static void c1e_idle(void)
 		default_idle();
 }
 
+static void (*local_idle)(void);
+DEFINE_PER_CPU(struct cpuidle_device, idle_devices);
+
+struct cpuidle_driver cpuidle_default_driver = {
+	.name =         "cpuidle_default",
+};
+
+static int local_idle_loop(struct cpuidle_device *dev, struct cpuidle_state *st)
+{
+	ktime_t t1, t2;
+	s64 diff;
+	int ret;
+
+	t1 = ktime_get();
+	local_idle();
+	t2 = ktime_get();
+
+	diff = ktime_to_us(ktime_sub(t2, t1));
+	if (diff > INT_MAX)
+		diff = INT_MAX;
+	ret = (int) diff;
+
+	return ret;
+}
+static int __cpuinit setup_cpuidle_simple(void)
+{
+	struct cpuidle_device *dev;
+	int cpu;
+
+	if (!cpuidle_curr_driver)
+		cpuidle_register_driver(&cpuidle_default_driver);
+
+	for_each_online_cpu(cpu) {
+		dev = &per_cpu(idle_devices, cpu);
+		dev->cpu = cpu;
+		dev->states[0].enter = local_idle_loop;
+		dev->state_count = 1;
+		cpuidle_register_device(dev);
+	}
+	return 0;
+}
+late_initcall(setup_cpuidle_simple);
+
 void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
 {
 #ifdef CONFIG_SMP
-	if (pm_idle == poll_idle && smp_num_siblings > 1) {
+	if (local_idle == poll_idle && smp_num_siblings > 1) {
 		printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
 			" performance may degrade.\n");
 	}
 #endif
-	if (pm_idle)
+	if (local_idle)
 		return;
 
 	if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
@@ -547,18 +586,20 @@ void __cpuinit select_idle_routine(const
 		 * One CPU supports mwait => All CPUs supports mwait
 		 */
 		printk(KERN_INFO "using mwait in idle threads.\n");
-		pm_idle = mwait_idle;
+		local_idle = mwait_idle;
 	} else if (check_c1e_idle(c)) {
 		printk(KERN_INFO "using C1E aware idle routine\n");
-		pm_idle = c1e_idle;
+		local_idle = c1e_idle;
 	} else
-		pm_idle = default_idle;
+		local_idle = default_idle;
+
+	return;
 }
 
 void __init init_c1e_mask(void)
 {
 	/* If we're using c1e_idle, we need to allocate c1e_mask. */
-	if (pm_idle == c1e_idle) {
+	if (local_idle == c1e_idle) {
 		alloc_cpumask_var(&c1e_mask, GFP_KERNEL);
 		cpumask_clear(c1e_mask);
 	}
@@ -571,7 +612,7 @@ static int __init idle_setup(char *str)
 
 	if (!strcmp(str, "poll")) {
 		printk("using polling idle threads.\n");
-		pm_idle = poll_idle;
+		local_idle = poll_idle;
 	} else if (!strcmp(str, "mwait"))
 		force_mwait = 1;
 	else if (!strcmp(str, "halt")) {
@@ -582,7 +623,7 @@ static int __init idle_setup(char *str)
 		 * To continue to load the CPU idle driver, don't touch
 		 * the boot_option_idle_override.
 		 */
-		pm_idle = default_idle;
+		local_idle = default_idle;
 		idle_halt = 1;
 		return 0;
 	} else if (!strcmp(str, "nomwait")) {
Index: linux.trees.git/arch/x86/kernel/process_32.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/process_32.c
+++ linux.trees.git/arch/x86/kernel/process_32.c
@@ -40,6 +40,7 @@
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/kdebug.h>
+#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -113,7 +114,7 @@ void cpu_idle(void)
 			local_irq_disable();
 			/* Don't trace irqs off for idle */
 			stop_critical_timings();
-			pm_idle();
+			cpuidle_idle_call();
 			start_critical_timings();
 		}
 		tick_nohz_restart_sched_tick();
Index: linux.trees.git/arch/x86/kernel/process_64.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/process_64.c
+++ linux.trees.git/arch/x86/kernel/process_64.c
@@ -39,6 +39,7 @@
 #include <linux/io.h>
 #include <linux/ftrace.h>
 #include <linux/dmi.h>
+#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -142,7 +143,7 @@ void cpu_idle(void)
 			enter_idle();
 			/* Don't trace irqs off for idle */
 			stop_critical_timings();
-			pm_idle();
+			cpuidle_idle_call();
 			start_critical_timings();
 			/* In many cases the interrupt that ended idle
 			   has already called exit_idle. But some idle
Index: linux.trees.git/arch/x86/kernel/apm_32.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/apm_32.c
+++ linux.trees.git/arch/x86/kernel/apm_32.c
@@ -2257,6 +2257,38 @@ static struct dmi_system_id __initdata a
 	{ }
 };
 
+DEFINE_PER_CPU(struct cpuidle_device, apm_idle_devices);
+
+struct cpuidle_driver cpuidle_apm_driver = {
+	.name =         "cpuidle_apm",
+};
+
+void __cpuinit setup_cpuidle_apm(void)
+{
+	struct cpuidle_device *dev;
+
+	if (!cpuidle_curr_driver)
+		cpuidle_register_driver(&cpuidle_apm_driver);
+
+	dev = &per_cpu(apm_idle_devices, smp_processor_id());
+	dev->cpu = smp_processor_id();
+	dev->states[0].enter = apm_cpu_idle;
+	dev->state_count = 1;
+	cpuidle_register_device(dev);
+}
+
+void exit_cpuidle_apm(void)
+{
+	struct cpuidle_device *dev;
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		dev = &per_cpu(apm_idle_devices, cpu);
+		cpuidle_unregister_device(dev);
+	}
+}
+
+
 /*
  * Just start the APM thread. We do NOT want to do APM BIOS
  * calls from anything but the APM thread, if for no other reason
@@ -2394,8 +2426,7 @@ static int __init apm_init(void)
 	if (HZ != 100)
 		idle_period = (idle_period * HZ) / 100;
 	if (idle_threshold < 100) {
-		original_pm_idle = pm_idle;
-		pm_idle  = apm_cpu_idle;
+		setup_cpuidle_apm();
 		set_pm_idle = 1;
 	}
 
@@ -2407,7 +2438,7 @@ static void __exit apm_exit(void)
 	int error;
 
 	if (set_pm_idle) {
-		pm_idle = original_pm_idle;
+		exit_cpuidle_apm();
 		/*
 		 * We are about to unload the current idle thread pm callback
 		 * (pm_idle), Wait for all processors to update cached/local
Index: linux.trees.git/arch/x86/xen/setup.c
===================================================================
--- linux.trees.git.orig/arch/x86/xen/setup.c
+++ linux.trees.git/arch/x86/xen/setup.c
@@ -8,6 +8,7 @@
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/pm.h>
+#include <linux/cpuidle.h>
 
 #include <asm/elf.h>
 #include <asm/vdso.h>
@@ -151,6 +152,25 @@ void __cpuinit xen_enable_syscall(void)
 #endif /* CONFIG_X86_64 */
 }
 
+DEFINE_PER_CPU(struct cpuidle_device, idle_devices);
+struct cpuidle_driver cpuidle_xen_driver = {
+	.name =         "cpuidle_xen",
+};
+
+void __cpuinit setup_cpuidle_xen(void)
+{
+	struct cpuidle_device *dev;
+
+	if (!cpuidle_curr_driver)
+		cpuidle_register_driver(&cpuidle_xen_driver);
+
+	dev = &per_cpu(idle_devices, smp_processor_id());
+	dev->cpu = smp_processor_id();
+	dev->states[0].enter = xen_idle;
+	dev->state_count = 1;
+	cpuidle_register_device(dev);
+}
+
 void __init xen_arch_setup(void)
 {
 	struct physdev_set_iopl set_iopl;
@@ -186,7 +206,7 @@ void __init xen_arch_setup(void)
 	       MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
 	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
 
-	pm_idle = xen_idle;
+	setup_cpuidle_xen();
 
 	paravirt_disable_iospace();