MIPS: JZ4740: Add clocksource/clockevent support.

Add clocksource and clockevent support for the timer/counter unit on
JZ4740 SoCs.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1397/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 144 insertions, 0 deletions

diff --git a/arch/mips/jz4740/time.c b/arch/mips/jz4740/time.c
new file mode 100644
index 000000000000..fe01678d94fd
--- /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,
+        .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);
+}