From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 drivers/clocksource/mips-gic-timer.c | 177 +++++++++++++++++++++++++++++++++++
 1 file changed, 177 insertions(+)
 create mode 100644 drivers/clocksource/mips-gic-timer.c

(limited to 'drivers/clocksource/mips-gic-timer.c')

diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
new file mode 100644
index 000000000..b81ed1a53
--- /dev/null
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -0,0 +1,177 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2012 MIPS Technologies, Inc.  All rights reserved.
+ */
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irqchip/mips-gic.h>
+#include <linux/notifier.h>
+#include <linux/of_irq.h>
+#include <linux/percpu.h>
+#include <linux/smp.h>
+#include <linux/time.h>
+
+static DEFINE_PER_CPU(struct clock_event_device, gic_clockevent_device);
+static int gic_timer_irq;
+static unsigned int gic_frequency;
+
+static int gic_next_event(unsigned long delta, struct clock_event_device *evt)
+{
+	u64 cnt;
+	int res;
+
+	cnt = gic_read_count();
+	cnt += (u64)delta;
+	gic_write_cpu_compare(cnt, cpumask_first(evt->cpumask));
+	res = ((int)(gic_read_count() - cnt) >= 0) ? -ETIME : 0;
+	return res;
+}
+
+static void gic_set_clock_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt)
+{
+	/* Nothing to do ...  */
+}
+
+static irqreturn_t gic_compare_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *cd = dev_id;
+
+	gic_write_compare(gic_read_compare());
+	cd->event_handler(cd);
+	return IRQ_HANDLED;
+}
+
+struct irqaction gic_compare_irqaction = {
+	.handler = gic_compare_interrupt,
+	.percpu_dev_id = &gic_clockevent_device,
+	.flags = IRQF_PERCPU | IRQF_TIMER,
+	.name = "timer",
+};
+
+static void gic_clockevent_cpu_init(struct clock_event_device *cd)
+{
+	unsigned int cpu = smp_processor_id();
+
+	cd->name		= "MIPS GIC";
+	cd->features		= CLOCK_EVT_FEAT_ONESHOT |
+				  CLOCK_EVT_FEAT_C3STOP;
+
+	cd->rating		= 350;
+	cd->irq			= gic_timer_irq;
+	cd->cpumask		= cpumask_of(cpu);
+	cd->set_next_event	= gic_next_event;
+	cd->set_mode		= gic_set_clock_mode;
+
+	clockevents_config_and_register(cd, gic_frequency, 0x300, 0x7fffffff);
+
+	enable_percpu_irq(gic_timer_irq, IRQ_TYPE_NONE);
+}
+
+static void gic_clockevent_cpu_exit(struct clock_event_device *cd)
+{
+	disable_percpu_irq(gic_timer_irq);
+}
+
+static int gic_cpu_notifier(struct notifier_block *nb, unsigned long action,
+				void *data)
+{
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_STARTING:
+		gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device));
+		break;
+	case CPU_DYING:
+		gic_clockevent_cpu_exit(this_cpu_ptr(&gic_clockevent_device));
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block gic_cpu_nb = {
+	.notifier_call = gic_cpu_notifier,
+};
+
+static int gic_clockevent_init(void)
+{
+	if (!cpu_has_counter || !gic_frequency)
+		return -ENXIO;
+
+	setup_percpu_irq(gic_timer_irq, &gic_compare_irqaction);
+
+	register_cpu_notifier(&gic_cpu_nb);
+
+	gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device));
+
+	return 0;
+}
+
+static cycle_t gic_hpt_read(struct clocksource *cs)
+{
+	return gic_read_count();
+}
+
+static struct clocksource gic_clocksource = {
+	.name	= "GIC",
+	.read	= gic_hpt_read,
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void __init __gic_clocksource_init(void)
+{
+	/* Set clocksource mask. */
+	gic_clocksource.mask = CLOCKSOURCE_MASK(gic_get_count_width());
+
+	/* Calculate a somewhat reasonable rating value. */
+	gic_clocksource.rating = 200 + gic_frequency / 10000000;
+
+	clocksource_register_hz(&gic_clocksource, gic_frequency);
+
+	gic_clockevent_init();
+
+	/* And finally start the counter */
+	gic_start_count();
+}
+
+void __init gic_clocksource_init(unsigned int frequency)
+{
+	gic_frequency = frequency;
+	gic_timer_irq = MIPS_GIC_IRQ_BASE +
+		GIC_LOCAL_TO_HWIRQ(GIC_LOCAL_INT_COMPARE);
+
+	__gic_clocksource_init();
+}
+
+static void __init gic_clocksource_of_init(struct device_node *node)
+{
+	struct clk *clk;
+
+	if (WARN_ON(!gic_present || !node->parent ||
+		    !of_device_is_compatible(node->parent, "mti,gic")))
+		return;
+
+	clk = of_clk_get(node, 0);
+	if (!IS_ERR(clk)) {
+		gic_frequency = clk_get_rate(clk);
+		clk_put(clk);
+	} else if (of_property_read_u32(node, "clock-frequency",
+					&gic_frequency)) {
+		pr_err("GIC frequency not specified.\n");
+		return;
+	}
+	gic_timer_irq = irq_of_parse_and_map(node, 0);
+	if (!gic_timer_irq) {
+		pr_err("GIC timer IRQ not specified.\n");
+		return;
+	}
+
+	__gic_clocksource_init();
+}
+CLOCKSOURCE_OF_DECLARE(mips_gic_timer, "mti,gic-timer",
+		       gic_clocksource_of_init);
-- 
cgit v1.2.3-54-g00ecf