[RFC][PATCH 05/26] MIPS: JZ4740: Add clocksource/clockevent support.

[Lars-Peter Clausen <lars@metafoo.de>]

This patch add clocksource and clockevent support for the timer/counter unit on
JZ4740 SoCs.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
 arch/mips/jz4740/time.c |  144 +++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 144 insertions(+), 0 deletions(-)
 create mode 100644 arch/mips/jz4740/time.c

diff --git a/arch/mips/jz4740/time.c b/arch/mips/jz4740/time.c
new file mode 100644
index 0000000..da8183f
--- /dev/null
+++ b/arch/mips/jz4740/time.c
@@ -0,0 +1,144 @@
+/*
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  JZ4740 platform time support
+ *
+ *  This program is free software; you can redistribute	 it and/or modify it
+ *  under  the terms of	 the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the	License, or (at your
+ *  option) any later version.
+ *
+ *  You should have received a copy of the  GNU General Public License along
+ *  with this program; if not, write  to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+
+#include <linux/clockchips.h>
+
+#include <asm/mach-jz4740/irq.h>
+#include <asm/time.h>
+
+#include "clock.h"
+#include "timer.h"
+
+#define TIMER_CLOCKEVENT 0
+#define TIMER_CLOCKSOURCE 1
+
+static uint16_t jz4740_jiffies_per_tick;
+
+static cycle_t jz4740_clocksource_read(struct clocksource *cs)
+{
+	return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
+}
+
+static struct clocksource jz4740_clocksource = {
+	.name = "jz4740-timer",
+	.rating = 200,
+	.read = jz4740_clocksource_read,
+	.mask = CLOCKSOURCE_MASK(16),
+	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
+{
+	struct clock_event_device *cd = devid;
+
+	jz4740_timer_ack_full(TIMER_CLOCKEVENT);
+
+	if (cd->mode != CLOCK_EVT_MODE_PERIODIC)
+		jz4740_timer_disable(TIMER_CLOCKEVENT);
+
+	cd->event_handler(cd);
+
+	return IRQ_HANDLED;
+}
+
+static void jz4740_clockevent_set_mode(enum clock_event_mode mode,
+	struct clock_event_device *cd)
+{
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
+		jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
+	case CLOCK_EVT_MODE_RESUME:
+		jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
+		jz4740_timer_enable(TIMER_CLOCKEVENT);
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		jz4740_timer_disable(TIMER_CLOCKEVENT);
+		break;
+	default:
+		break;
+	}
+}
+
+static int jz4740_clockevent_set_next(unsigned long evt,
+	struct clock_event_device *cd)
+{
+	jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
+	jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
+	jz4740_timer_enable(TIMER_CLOCKEVENT);
+
+	return 0;
+}
+
+static struct clock_event_device jz4740_clockevent = {
+	.name = "jz4740-timer",
+	.features = CLOCK_EVT_FEAT_PERIODIC,
+	.set_next_event = jz4740_clockevent_set_next,
+	.set_mode = jz4740_clockevent_set_mode,
+	.rating = 200,
+	.irq = JZ4740_IRQ_TCU0,
+};
+
+static struct irqaction timer_irqaction = {
+	.handler	= jz4740_clockevent_irq,
+	.flags		= IRQF_PERCPU | IRQF_TIMER | IRQF_DISABLED,
+	.name		= "jz4740-timerirq",
+	.dev_id		= &jz4740_clockevent,
+};
+
+void __init plat_time_init(void)
+{
+	int ret;
+	uint32_t clk_rate;
+	uint16_t ctrl;
+
+	jz4740_timer_init();
+
+	clk_rate = jz4740_clock_bdata.ext_rate >> 4;
+	jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
+
+	clockevent_set_clock(&jz4740_clockevent, clk_rate);
+	jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
+	jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
+	jz4740_clockevent.cpumask = cpumask_of(0);
+
+	clockevents_register_device(&jz4740_clockevent);
+
+	clocksource_set_clock(&jz4740_clocksource, clk_rate);
+	ret = clocksource_register(&jz4740_clocksource);
+
+	if (ret)
+		printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
+
+	setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction);
+
+	ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
+
+	jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
+	jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
+
+	jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
+	jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
+
+	jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
+
+	jz4740_timer_enable(TIMER_CLOCKEVENT);
+	jz4740_timer_enable(TIMER_CLOCKSOURCE);
+}
-- 
1.5.6.5