genirq/timings: Add selftest for irqs circular buffer

After testing the per cpu interrupt circular event, make sure the per
interrupt circular buffer usage is correct.

Add tests to validate the interrupt circular buffer.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20190527205521.12091-8-daniel.lezcano@linaro.org

kernel/irq/timings.c

@@ -629,6 +629,141 @@ int irq_timings_alloc(int irq)
 }
 
 #ifdef CONFIG_TEST_IRQ_TIMINGS
+struct timings_intervals {
+	u64 *intervals;
+	size_t count;
+};
+
+/*
+ * Intervals are given in nanosecond base
+ */
+static u64 intervals0[] __initdata = {
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000,
+};
+
+static u64 intervals1[] __initdata = {
+	223947000, 1240000, 1384000, 1386000, 1386000,
+	217416000, 1236000, 1384000, 1386000, 1387000,
+	214719000, 1241000, 1386000, 1387000, 1384000,
+	213696000, 1234000, 1384000, 1386000, 1388000,
+	219904000, 1240000, 1385000, 1389000, 1385000,
+	212240000, 1240000, 1386000, 1386000, 1386000,
+	214415000, 1236000, 1384000, 1386000, 1387000,
+	214276000, 1234000,
+};
+
+static u64 intervals2[] __initdata = {
+	4000, 3000, 5000, 100000,
+	3000, 3000, 5000, 117000,
+	4000, 4000, 5000, 112000,
+	4000, 3000, 4000, 110000,
+	3000, 5000, 3000, 117000,
+	4000, 4000, 5000, 112000,
+	4000, 3000, 4000, 110000,
+	3000, 4000, 5000, 112000,
+	4000,
+};
+
+static u64 intervals3[] __initdata = {
+	1385000, 212240000, 1240000,
+	1386000, 214415000, 1236000,
+	1384000, 214276000, 1234000,
+	1386000, 214415000, 1236000,
+	1385000, 212240000, 1240000,
+	1386000, 214415000, 1236000,
+	1384000, 214276000, 1234000,
+	1386000, 214415000, 1236000,
+	1385000, 212240000, 1240000,
+};
+
+static u64 intervals4[] __initdata = {
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000,
+};
+
+static struct timings_intervals tis[] __initdata = {
+	{ intervals0, ARRAY_SIZE(intervals0) },
+	{ intervals1, ARRAY_SIZE(intervals1) },
+	{ intervals2, ARRAY_SIZE(intervals2) },
+	{ intervals3, ARRAY_SIZE(intervals3) },
+	{ intervals4, ARRAY_SIZE(intervals4) },
+};
+
+static int __init irq_timings_test_irqs(struct timings_intervals *ti)
+{
+	struct irqt_stat __percpu *s;
+	struct irqt_stat *irqs;
+	int i, index, ret, irq = 0xACE5;
+
+	ret = irq_timings_alloc(irq);
+	if (ret) {
+		pr_err("Failed to allocate irq timings\n");
+		return ret;
+	}
+
+	s = idr_find(&irqt_stats, irq);
+	if (!s) {
+		ret = -EIDRM;
+		goto out;
+	}
+
+	irqs = this_cpu_ptr(s);
+
+	for (i = 0; i < ti->count; i++) {
+
+		index = irq_timings_interval_index(ti->intervals[i]);
+		pr_debug("%d: interval=%llu ema_index=%d\n",
+			 i, ti->intervals[i], index);
+
+		__irq_timings_store(irq, irqs, ti->intervals[i]);
+		if (irqs->circ_timings[i & IRQ_TIMINGS_MASK] != index) {
+			pr_err("Failed to store in the circular buffer\n");
+			goto out;
+		}
+	}
+
+	if (irqs->count != ti->count) {
+		pr_err("Count differs\n");
+		goto out;
+	}
+
+	ret = 0;
+out:
+	irq_timings_free(irq);
+
+	return ret;
+}
+
+static int __init irq_timings_irqs_selftest(void)
+{
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(tis); i++) {
+		pr_info("---> Injecting intervals number #%d (count=%zd)\n",
+			i, tis[i].count);
+		ret = irq_timings_test_irqs(&tis[i]);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
 static int __init irq_timings_test_irqts(struct irq_timings *irqts,
 					 unsigned count)
 {
@@ -736,7 +871,11 @@ static int __init irq_timings_selftest(void)
 	}
 
 	ret = irq_timings_irqts_selftest();
+	if (ret)
+		goto out;
 
+	ret = irq_timings_irqs_selftest();
+out:
 	pr_info("---------- selftest end with %s -----------\n",
 		ret ? "failure" : "success");