[CPUFREQ] use dynamic debug instead of custom infrastructure

With dynamic debug having gained the capability to report debug messages
also during the boot process, it offers a far superior interface for
debug messages than the custom cpufreq infrastructure. As a first step,
remove the old cpufreq_debug_printk() function and replace it with a call
to the generic pr_debug() function.

How can dynamic debug be used on cpufreq? You need a kernel which has
CONFIG_DYNAMIC_DEBUG enabled.

To enabled debugging during runtime, mount debugfs and

$ echo -n 'module cpufreq +p' > /sys/kernel/debug/dynamic_debug/control

for debugging the complete "cpufreq" module. To achieve the same goal during
boot, append

	ddebug_query="module cpufreq +p"

as a boot parameter to the kernel of your choice.

For more detailled instructions, please see
Documentation/dynamic-debug-howto.txt

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Dave Jones <davej@redhat.com>

1 files changed, 37 insertions, 143 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 7c10f96c5ae9..1e08af43ae72 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -32,9 +32,6 @@
 
 #include <trace/events/power.h>
 
-#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
-						"cpufreq-core", msg)
-
 /**
  * The "cpufreq driver" - the arch- or hardware-dependent low
  * level driver of CPUFreq support, and its spinlock. This lock
@@ -181,93 +178,6 @@ EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
 
 
 /*********************************************************************
- *                     UNIFIED DEBUG HELPERS                         *
- *********************************************************************/
-#ifdef CONFIG_CPU_FREQ_DEBUG
-
-/* what part(s) of the CPUfreq subsystem are debugged? */
-static unsigned int debug;
-
-/* is the debug output ratelimit'ed using printk_ratelimit? User can
- * set or modify this value.
- */
-static unsigned int debug_ratelimit = 1;
-
-/* is the printk_ratelimit'ing enabled? It's enabled after a successful
- * loading of a cpufreq driver, temporarily disabled when a new policy
- * is set, and disabled upon cpufreq driver removal
- */
-static unsigned int disable_ratelimit = 1;
-static DEFINE_SPINLOCK(disable_ratelimit_lock);
-
-static void cpufreq_debug_enable_ratelimit(void)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&disable_ratelimit_lock, flags);
-	if (disable_ratelimit)
-		disable_ratelimit--;
-	spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
-}
-
-static void cpufreq_debug_disable_ratelimit(void)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&disable_ratelimit_lock, flags);
-	disable_ratelimit++;
-	spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
-}
-
-void cpufreq_debug_printk(unsigned int type, const char *prefix,
-			const char *fmt, ...)
-{
-	char s[256];
-	va_list args;
-	unsigned int len;
-	unsigned long flags;
-
-	WARN_ON(!prefix);
-	if (type & debug) {
-		spin_lock_irqsave(&disable_ratelimit_lock, flags);
-		if (!disable_ratelimit && debug_ratelimit
-					&& !printk_ratelimit()) {
-			spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
-			return;
-		}
-		spin_unlock_irqrestore(&disable_ratelimit_lock, flags);
-
-		len = snprintf(s, 256, KERN_DEBUG "%s: ", prefix);
-
-		va_start(args, fmt);
-		len += vsnprintf(&s[len], (256 - len), fmt, args);
-		va_end(args);
-
-		printk(s);
-
-		WARN_ON(len < 5);
-	}
-}
-EXPORT_SYMBOL(cpufreq_debug_printk);
-
-
-module_param(debug, uint, 0644);
-MODULE_PARM_DESC(debug, "CPUfreq debugging: add 1 to debug core,"
-			" 2 to debug drivers, and 4 to debug governors.");
-
-module_param(debug_ratelimit, uint, 0644);
-MODULE_PARM_DESC(debug_ratelimit, "CPUfreq debugging:"
-					" set to 0 to disable ratelimiting.");
-
-#else /* !CONFIG_CPU_FREQ_DEBUG */
-
-static inline void cpufreq_debug_enable_ratelimit(void) { return; }
-static inline void cpufreq_debug_disable_ratelimit(void) { return; }
-
-#endif /* CONFIG_CPU_FREQ_DEBUG */
-
-
-/*********************************************************************
  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
  *********************************************************************/
 
@@ -291,7 +201,7 @@ static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 	if (!l_p_j_ref_freq) {
 		l_p_j_ref = loops_per_jiffy;
 		l_p_j_ref_freq = ci->old;
-		dprintk("saving %lu as reference value for loops_per_jiffy; "
+		pr_debug("saving %lu as reference value for loops_per_jiffy; "
 			"freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
 	}
 	if ((val == CPUFREQ_PRECHANGE  && ci->old < ci->new) ||
@@ -299,7 +209,7 @@ static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
 	    (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
 		loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
 								ci->new);
-		dprintk("scaling loops_per_jiffy to %lu "
+		pr_debug("scaling loops_per_jiffy to %lu "
 			"for frequency %u kHz\n", loops_per_jiffy, ci->new);
 	}
 }
@@ -326,7 +236,7 @@ void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
 	BUG_ON(irqs_disabled());
 
 	freqs->flags = cpufreq_driver->flags;
-	dprintk("notification %u of frequency transition to %u kHz\n",
+	pr_debug("notification %u of frequency transition to %u kHz\n",
 		state, freqs->new);
 
 	policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
@@ -340,7 +250,7 @@ void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
 		if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
 			if ((policy) && (policy->cpu == freqs->cpu) &&
 			    (policy->cur) && (policy->cur != freqs->old)) {
-				dprintk("Warning: CPU frequency is"
+				pr_debug("Warning: CPU frequency is"
 					" %u, cpufreq assumed %u kHz.\n",
 					freqs->old, policy->cur);
 				freqs->old = policy->cur;
@@ -353,7 +263,7 @@ void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
 
 	case CPUFREQ_POSTCHANGE:
 		adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
-		dprintk("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
+		pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
 			(unsigned long)freqs->cpu);
 		trace_power_frequency(POWER_PSTATE, freqs->new, freqs->cpu);
 		trace_cpu_frequency(freqs->new, freqs->cpu);
@@ -753,7 +663,7 @@ no_policy:
 static void cpufreq_sysfs_release(struct kobject *kobj)
 {
 	struct cpufreq_policy *policy = to_policy(kobj);
-	dprintk("last reference is dropped\n");
+	pr_debug("last reference is dropped\n");
 	complete(&policy->kobj_unregister);
 }
 
@@ -788,7 +698,7 @@ static int cpufreq_add_dev_policy(unsigned int cpu,
 	gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
 	if (gov) {
 		policy->governor = gov;
-		dprintk("Restoring governor %s for cpu %d\n",
+		pr_debug("Restoring governor %s for cpu %d\n",
 		       policy->governor->name, cpu);
 	}
 #endif
@@ -824,7 +734,7 @@ static int cpufreq_add_dev_policy(unsigned int cpu,
 			per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
 			spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
-			dprintk("CPU already managed, adding link\n");
+			pr_debug("CPU already managed, adding link\n");
 			ret = sysfs_create_link(&sys_dev->kobj,
 						&managed_policy->kobj,
 						"cpufreq");
@@ -865,7 +775,7 @@ static int cpufreq_add_dev_symlink(unsigned int cpu,
 		if (!cpu_online(j))
 			continue;
 
-		dprintk("CPU %u already managed, adding link\n", j);
+		pr_debug("CPU %u already managed, adding link\n", j);
 		managed_policy = cpufreq_cpu_get(cpu);
 		cpu_sys_dev = get_cpu_sysdev(j);
 		ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
@@ -941,7 +851,7 @@ static int cpufreq_add_dev_interface(unsigned int cpu,
 	policy->user_policy.governor = policy->governor;
 
 	if (ret) {
-		dprintk("setting policy failed\n");
+		pr_debug("setting policy failed\n");
 		if (cpufreq_driver->exit)
 			cpufreq_driver->exit(policy);
 	}
@@ -977,8 +887,7 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
 	if (cpu_is_offline(cpu))
 		return 0;
 
-	cpufreq_debug_disable_ratelimit();
-	dprintk("adding CPU %u\n", cpu);
+	pr_debug("adding CPU %u\n", cpu);
 
 #ifdef CONFIG_SMP
 	/* check whether a different CPU already registered this
@@ -986,7 +895,6 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
 	policy = cpufreq_cpu_get(cpu);
 	if (unlikely(policy)) {
 		cpufreq_cpu_put(policy);
-		cpufreq_debug_enable_ratelimit();
 		return 0;
 	}
 #endif
@@ -1037,7 +945,7 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
 	 */
 	ret = cpufreq_driver->init(policy);
 	if (ret) {
-		dprintk("initialization failed\n");
+		pr_debug("initialization failed\n");
 		goto err_unlock_policy;
 	}
 	policy->user_policy.min = policy->min;
@@ -1063,8 +971,7 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
 
 	kobject_uevent(&policy->kobj, KOBJ_ADD);
 	module_put(cpufreq_driver->owner);
-	dprintk("initialization complete\n");
-	cpufreq_debug_enable_ratelimit();
+	pr_debug("initialization complete\n");
 
 	return 0;
 
@@ -1088,7 +995,6 @@ err_free_policy:
 nomem_out:
 	module_put(cpufreq_driver->owner);
 module_out:
-	cpufreq_debug_enable_ratelimit();
 	return ret;
 }
 
@@ -1112,15 +1018,13 @@ static int __cpufreq_remove_dev(struct sys_device *sys_dev)
 	unsigned int j;
 #endif
 
-	cpufreq_debug_disable_ratelimit();
-	dprintk("unregistering CPU %u\n", cpu);
+	pr_debug("unregistering CPU %u\n", cpu);
 
 	spin_lock_irqsave(&cpufreq_driver_lock, flags);
 	data = per_cpu(cpufreq_cpu_data, cpu);
 
 	if (!data) {
 		spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
-		cpufreq_debug_enable_ratelimit();
 		unlock_policy_rwsem_write(cpu);
 		return -EINVAL;
 	}
@@ -1132,12 +1036,11 @@ static int __cpufreq_remove_dev(struct sys_device *sys_dev)
 	 * only need to unlink, put and exit
 	 */
 	if (unlikely(cpu != data->cpu)) {
-		dprintk("removing link\n");
+		pr_debug("removing link\n");
 		cpumask_clear_cpu(cpu, data->cpus);
 		spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
 		kobj = &sys_dev->kobj;
 		cpufreq_cpu_put(data);
-		cpufreq_debug_enable_ratelimit();
 		unlock_policy_rwsem_write(cpu);
 		sysfs_remove_link(kobj, "cpufreq");
 		return 0;
@@ -1170,7 +1073,7 @@ static int __cpufreq_remove_dev(struct sys_device *sys_dev)
 		for_each_cpu(j, data->cpus) {
 			if (j == cpu)
 				continue;
-			dprintk("removing link for cpu %u\n", j);
+			pr_debug("removing link for cpu %u\n", j);
 #ifdef CONFIG_HOTPLUG_CPU
 			strncpy(per_cpu(cpufreq_cpu_governor, j),
 				data->governor->name, CPUFREQ_NAME_LEN);
@@ -1199,17 +1102,15 @@ static int __cpufreq_remove_dev(struct sys_device *sys_dev)
 	 * not referenced anymore by anybody before we proceed with
 	 * unloading.
 	 */
-	dprintk("waiting for dropping of refcount\n");
+	pr_debug("waiting for dropping of refcount\n");
 	wait_for_completion(cmp);
-	dprintk("wait complete\n");
+	pr_debug("wait complete\n");
 
 	lock_policy_rwsem_write(cpu);
 	if (cpufreq_driver->exit)
 		cpufreq_driver->exit(data);
 	unlock_policy_rwsem_write(cpu);
 
-	cpufreq_debug_enable_ratelimit();
-
 #ifdef CONFIG_HOTPLUG_CPU
 	/* when the CPU which is the parent of the kobj is hotplugged
 	 * offline, check for siblings, and create cpufreq sysfs interface
@@ -1255,7 +1156,7 @@ static void handle_update(struct work_struct *work)
 	struct cpufreq_policy *policy =
 		container_of(work, struct cpufreq_policy, update);
 	unsigned int cpu = policy->cpu;
-	dprintk("handle_update for cpu %u called\n", cpu);
+	pr_debug("handle_update for cpu %u called\n", cpu);
 	cpufreq_update_policy(cpu);
 }
 
@@ -1273,7 +1174,7 @@ static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
 {
 	struct cpufreq_freqs freqs;
 
-	dprintk("Warning: CPU frequency out of sync: cpufreq and timing "
+	pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
 	       "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
 
 	freqs.cpu = cpu;
@@ -1376,7 +1277,7 @@ static int cpufreq_bp_suspend(void)
 	int cpu = smp_processor_id();
 	struct cpufreq_policy *cpu_policy;
 
-	dprintk("suspending cpu %u\n", cpu);
+	pr_debug("suspending cpu %u\n", cpu);
 
 	/* If there's no policy for the boot CPU, we have nothing to do. */
 	cpu_policy = cpufreq_cpu_get(cpu);
@@ -1414,7 +1315,7 @@ static void cpufreq_bp_resume(void)
 	int cpu = smp_processor_id();
 	struct cpufreq_policy *cpu_policy;
 
-	dprintk("resuming cpu %u\n", cpu);
+	pr_debug("resuming cpu %u\n", cpu);
 
 	/* If there's no policy for the boot CPU, we have nothing to do. */
 	cpu_policy = cpufreq_cpu_get(cpu);
@@ -1526,7 +1427,7 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
 {
 	int retval = -EINVAL;
 
-	dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
+	pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
 		target_freq, relation);
 	if (cpu_online(policy->cpu) && cpufreq_driver->target)
 		retval = cpufreq_driver->target(policy, target_freq, relation);
@@ -1612,7 +1513,7 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 	if (!try_module_get(policy->governor->owner))
 		return -EINVAL;
 
-	dprintk("__cpufreq_governor for CPU %u, event %u\n",
+	pr_debug("__cpufreq_governor for CPU %u, event %u\n",
 						policy->cpu, event);
 	ret = policy->governor->governor(policy, event);
 
@@ -1713,8 +1614,7 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
 {
 	int ret = 0;
 
-	cpufreq_debug_disable_ratelimit();
-	dprintk("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
+	pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
 		policy->min, policy->max);
 
 	memcpy(&policy->cpuinfo, &data->cpuinfo,
@@ -1751,19 +1651,19 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
 	data->min = policy->min;
 	data->max = policy->max;
 
-	dprintk("new min and max freqs are %u - %u kHz\n",
+	pr_debug("new min and max freqs are %u - %u kHz\n",
 					data->min, data->max);
 
 	if (cpufreq_driver->setpolicy) {
 		data->policy = policy->policy;
-		dprintk("setting range\n");
+		pr_debug("setting range\n");
 		ret = cpufreq_driver->setpolicy(policy);
 	} else {
 		if (policy->governor != data->governor) {
 			/* save old, working values */
 			struct cpufreq_governor *old_gov = data->governor;
 
-			dprintk("governor switch\n");
+			pr_debug("governor switch\n");
 
 			/* end old governor */
 			if (data->governor)
@@ -1773,7 +1673,7 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
 			data->governor = policy->governor;
 			if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
 				/* new governor failed, so re-start old one */
-				dprintk("starting governor %s failed\n",
+				pr_debug("starting governor %s failed\n",
 							data->governor->name);
 				if (old_gov) {
 					data->governor = old_gov;
@@ -1785,12 +1685,11 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data,
 			}
 			/* might be a policy change, too, so fall through */
 		}
-		dprintk("governor: change or update limits\n");
+		pr_debug("governor: change or update limits\n");
 		__cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
 	}
 
 error_out:
-	cpufreq_debug_enable_ratelimit();
 	return ret;
 }
 
@@ -1817,7 +1716,7 @@ int cpufreq_update_policy(unsigned int cpu)
 		goto fail;
 	}
 
-	dprintk("updating policy for CPU %u\n", cpu);
+	pr_debug("updating policy for CPU %u\n", cpu);
 	memcpy(&policy, data, sizeof(struct cpufreq_policy));
 	policy.min = data->user_policy.min;
 	policy.max = data->user_policy.max;
@@ -1829,7 +1728,7 @@ int cpufreq_update_policy(unsigned int cpu)
 	if (cpufreq_driver->get) {
 		policy.cur = cpufreq_driver->get(cpu);
 		if (!data->cur) {
-			dprintk("Driver did not initialize current freq");
+			pr_debug("Driver did not initialize current freq");
 			data->cur = policy.cur;
 		} else {
 			if (data->cur != policy.cur)
@@ -1905,7 +1804,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
 	    ((!driver_data->setpolicy) && (!driver_data->target)))
 		return -EINVAL;
 
-	dprintk("trying to register driver %s\n", driver_data->name);
+	pr_debug("trying to register driver %s\n", driver_data->name);
 
 	if (driver_data->setpolicy)
 		driver_data->flags |= CPUFREQ_CONST_LOOPS;
@@ -1936,15 +1835,14 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
 
 		/* if all ->init() calls failed, unregister */
 		if (ret) {
-			dprintk("no CPU initialized for driver %s\n",
+			pr_debug("no CPU initialized for driver %s\n",
 							driver_data->name);
 			goto err_sysdev_unreg;
 		}
 	}
 
 	register_hotcpu_notifier(&cpufreq_cpu_notifier);
-	dprintk("driver %s up and running\n", driver_data->name);
-	cpufreq_debug_enable_ratelimit();
+	pr_debug("driver %s up and running\n", driver_data->name);
 
 	return 0;
 err_sysdev_unreg:
@@ -1971,14 +1869,10 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver)
 {
 	unsigned long flags;
 
-	cpufreq_debug_disable_ratelimit();
-
-	if (!cpufreq_driver || (driver != cpufreq_driver)) {
-		cpufreq_debug_enable_ratelimit();
+	if (!cpufreq_driver || (driver != cpufreq_driver))
 		return -EINVAL;
-	}
 
-	dprintk("unregistering driver %s\n", driver->name);
+	pr_debug("unregistering driver %s\n", driver->name);
 
 	sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
 	unregister_hotcpu_notifier(&cpufreq_cpu_notifier);