ENGR00176177-2 Add irq count mechanism to interactive governor

Add irq count to CPUFreq as a freq change condition.
Because some devices' working mode is unable to issue
CPUFreq change because of low CPU loading, but the cpu
freq will impact these devices' performace significantly.

Interactive govervor will sample the cpu loading as well
as the irq count which is registered. If the
loading or the irq count exceed the threshold we set,
governor will issue an CPUFreq change request.

These devices' irq threshold and enable/disable can be modified
via /sys/devices/system/cpu/cpufreq/interactive/irq_scaling

echo 0xAABBBC to change the default setting as below
AA : irq number
BBB: threshold
C  :enable or disable

Currently only enable USDHC3, USDHC4, GPU, SATA and
USB by default, we can add device to the init struct which is
located in arch/arm/mach-mx6/irq.c.

Signed-off-by: Anson Huang <b20788@freescale.com>

2 files changed, 142 insertions, 2 deletions

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index e342910d8374..bb49f40e8a8f 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -28,6 +28,7 @@
 #include <linux/workqueue.h>
 #include <linux/kthread.h>
 #include <linux/mutex.h>
+#include <linux/kernel_stat.h>
 
 #include <asm/cputime.h>
 
@@ -77,6 +78,8 @@ static unsigned long min_sample_time;
  * The sample rate of the timer used to increase frequency
  */
 #define DEFAULT_TIMER_RATE (20 * USEC_PER_MSEC)
+#define CPUFREQ_IRQ_LEN 60
+#define CPUFREQ_NOTE_LEN 120
 static unsigned long timer_rate;
 
 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
@@ -92,6 +95,44 @@ struct cpufreq_governor cpufreq_gov_interactive = {
 	.owner = THIS_MODULE,
 };
 
+static struct irq_tuner irq_tuner_ins[MAX_CPUFREQ_IRQ_NUMBER];
+static struct irq_desc *cpufreq_irq_desc[MAX_CPUFREQ_IRQ_NUMBER];
+
+static bool cpufreq_interactive_check_irq(void)
+{
+	bool val;
+	unsigned int irq_count, i;
+	static unsigned int irq_count_start[MAX_CPUFREQ_IRQ_NUMBER];
+	static unsigned int irq_count_end[MAX_CPUFREQ_IRQ_NUMBER];
+
+	val = false;
+	for (i = 0; i < MAX_CPUFREQ_IRQ_NUMBER; i++) {
+		if (irq_tuner_ins[i].irq_number == 0)
+			break;
+		if (!irq_tuner_ins[i].enable)
+			continue;
+		if (irq_count_start[i] == 0)
+			irq_count_start[i] = cpufreq_irq_desc[i] &&
+			cpufreq_irq_desc[i]->kstat_irqs ?
+			*per_cpu_ptr(cpufreq_irq_desc[i]->kstat_irqs, 0) : 0;
+		else if (irq_count_end[i] == 0)
+			irq_count_end[i] = cpufreq_irq_desc[i] &&
+			cpufreq_irq_desc[i]->kstat_irqs ?
+			*per_cpu_ptr(cpufreq_irq_desc[i]->kstat_irqs, 0) : 0;
+		else {
+			irq_count = irq_count_end[i] - irq_count_start[i];
+			irq_count_start[i] = irq_count_end[i];
+			irq_count_end[i] = 0;
+		}
+		if (irq_count > irq_tuner_ins[i].up_threshold) {
+			irq_count = 0;
+			val = true;
+			break;
+		}
+	}
+
+	return val;
+}
 static void cpufreq_interactive_timer(unsigned long data)
 {
 	unsigned int delta_idle;
@@ -106,6 +147,7 @@ static void cpufreq_interactive_timer(unsigned long data)
 	unsigned int new_freq;
 	unsigned int index;
 	unsigned long flags;
+	bool irq_load;
 
 	smp_rmb();
 
@@ -164,11 +206,14 @@ static void cpufreq_interactive_timer(unsigned long data)
 	if (load_since_change > cpu_load)
 		cpu_load = load_since_change;
 
-	if (cpu_load >= go_hispeed_load) {
+	irq_load = cpufreq_interactive_check_irq();
+	if (cpu_load >= go_hispeed_load || irq_load) {
 		if (pcpu->policy->cur == pcpu->policy->min)
 			new_freq = hispeed_freq;
 		else
 			new_freq = pcpu->policy->max * cpu_load / 100;
+		if (irq_load)
+			new_freq = hispeed_freq;
 	} else {
 		new_freq = pcpu->policy->cur * cpu_load / 100;
 	}
@@ -522,11 +567,56 @@ static ssize_t store_timer_rate(struct kobject *kobj,
 static struct global_attr timer_rate_attr = __ATTR(timer_rate, 0644,
 		show_timer_rate, store_timer_rate);
 
+
+static ssize_t show_irq_param(struct kobject *kobj,
+			struct attribute *attr, char *buf)
+{
+	int i, j = 0;
+	j += scnprintf(&buf[j], CPUFREQ_NOTE_LEN, "Change irq setting by echo a data, format: 0xAABBBC, AA:irq number, BBB:up_threshold, C:enable\n");
+	for (i = 0; i < MAX_CPUFREQ_IRQ_NUMBER; i++) {
+		if (irq_tuner_ins[i].irq_number != 0)
+			j += scnprintf(&buf[j], CPUFREQ_IRQ_LEN, "irq number: %d, up_threshold %d, %s\n", irq_tuner_ins[i].irq_number, irq_tuner_ins[i].up_threshold, irq_tuner_ins[i].enable ? "enabled" : "disabled");
+	}
+
+	return j;
+}
+
+static ssize_t store_irq_param(struct kobject *kobj,
+			struct attribute *attr, const char *buf, size_t count)
+{
+	int ret, i;
+	unsigned long val;
+
+	ret = strict_strtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < MAX_CPUFREQ_IRQ_NUMBER; i++) {
+		if (irq_tuner_ins[i].irq_number == val >> 16)
+			break;
+	}
+
+	if (i >= MAX_CPUFREQ_IRQ_NUMBER) {
+		printk(KERN_WARNING "Invalid irq number!\n");
+		return -EINVAL;
+	}
+	irq_tuner_ins[i].irq_number = val >> 16;
+	irq_tuner_ins[i].up_threshold = (val & 0xFFF0) >> 4;
+	irq_tuner_ins[i].enable = (val & 0xF) ? true : false;
+
+	return count;
+}
+
+
+static struct global_attr irq_param_attr = __ATTR(irq_scaling, 0644,
+		show_irq_param, store_irq_param);
+
 static struct attribute *interactive_attributes[] = {
 	&hispeed_freq_attr.attr,
 	&go_hispeed_load_attr.attr,
 	&min_sample_time_attr.attr,
 	&timer_rate_attr.attr,
+	&irq_param_attr.attr,
 	NULL,
 };
 
@@ -665,7 +755,7 @@ static int __init cpufreq_interactive_init(void)
 
 	/* No rescuer thread, bind to CPU queuing the work for possibly
 	   warm cache (probably doesn't matter much). */
-	down_wq = alloc_workqueue("knteractive_down", 0, 1);
+	down_wq = alloc_workqueue("kinteractive_down", 0, 1);
 
 	if (!down_wq)
 		goto err_freeuptask;
@@ -686,6 +776,44 @@ err_freeuptask:
 	return -ENOMEM;
 }
 
+int cpufreq_gov_irq_tuner_register(struct irq_tuner dbs_irq_tuner)
+{
+	int i, ret;
+	static bool init_flag;
+
+	/* Init the global irq_tuner_ins structure */
+	if (!init_flag) {
+		for (i = 0; i < MAX_CPUFREQ_IRQ_NUMBER; i++) {
+			irq_tuner_ins[i].irq_number = 0;
+			irq_tuner_ins[i].up_threshold = 0;
+			irq_tuner_ins[i].enable = 0;
+		}
+		init_flag = true;
+	}
+
+	if (dbs_irq_tuner.irq_number == 0)
+		return -EINVAL;
+	/* Find an unused struct */
+	for (i = 0; i < MAX_CPUFREQ_IRQ_NUMBER; i++) {
+		if (irq_tuner_ins[i].irq_number != 0)
+			continue;
+		else
+			break;
+	}
+	/* Check index */
+	if (i >= MAX_CPUFREQ_IRQ_NUMBER) {
+		printk(KERN_WARNING "Too many irq number requested!\n");
+		return -EINVAL;
+	}
+
+	irq_tuner_ins[i].irq_number = dbs_irq_tuner.irq_number;
+	irq_tuner_ins[i].up_threshold = dbs_irq_tuner.up_threshold;
+	irq_tuner_ins[i].enable = dbs_irq_tuner.enable;
+	cpufreq_irq_desc[i] = irq_to_desc(irq_tuner_ins[i].irq_number);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cpufreq_gov_irq_tuner_register);
 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
 fs_initcall(cpufreq_interactive_init);
 #else
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index ae06dc9a0cda..a61416fe63f2 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -68,6 +68,18 @@ struct cpufreq_governor;
 /* /sys/devices/system/cpu/cpufreq: entry point for global variables */
 extern struct kobject *cpufreq_global_kobject;
 
+/* For some peripheral devices, which will generate irq very frequently
+ * and take very short time to handle irq, in this scenario, CPUFreq will
+ * not issue cpu freq change, but the devices' performance will be impacted
+ * significantly, we need to add irq number check to be as one condition of
+ * CPU freq change. */
+#define MAX_CPUFREQ_IRQ_NUMBER 10
+struct irq_tuner {
+	unsigned int irq_number;
+	unsigned int up_threshold;
+	bool enable;
+};
+
 #define CPUFREQ_ETERNAL			(-1)
 struct cpufreq_cpuinfo {
 	unsigned int		max_freq;