nios2: Time keeping

Add time keeping code for nios2.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

4 files changed, 407 insertions, 0 deletions

diff --git a/arch/nios2/include/asm/delay.h b/arch/nios2/include/asm/delay.h
new file mode 100644
index 000000000000..098e49bf3aa3
--- /dev/null
+++ b/arch/nios2/include/asm/delay.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2014 Altera Corporation
+ * Copyright (C) 2004 Microtronix Datacom Ltd
+ *
+ * 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.
+ */
+
+#ifndef _ASM_NIOS2_DELAY_H
+#define _ASM_NIOS2_DELAY_H
+
+#include <asm-generic/delay.h>
+
+/* Undefined functions to get compile-time errors */
+extern void __bad_udelay(void);
+extern void __bad_ndelay(void);
+
+extern unsigned long loops_per_jiffy;
+
+#endif /* _ASM_NIOS2_DELAY_H */
diff --git a/arch/nios2/include/asm/timex.h b/arch/nios2/include/asm/timex.h
new file mode 100644
index 000000000000..2f2abb28ec2f
--- /dev/null
+++ b/arch/nios2/include/asm/timex.h
@@ -0,0 +1,24 @@
+/* Copyright Altera Corporation (C) 2014. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef _ASM_NIOS2_TIMEX_H
+#define _ASM_NIOS2_TIMEX_H
+
+typedef unsigned long cycles_t;
+
+extern cycles_t get_cycles(void);
+
+#endif
diff --git a/arch/nios2/kernel/time.c b/arch/nios2/kernel/time.c
new file mode 100644
index 000000000000..d90ca1b854e0
--- /dev/null
+++ b/arch/nios2/kernel/time.c
@@ -0,0 +1,310 @@
+/*
+ * Copyright (C) 2013-2014 Altera Corporation
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ *
+ * 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.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#define ALTERA_TIMER_STATUS_REG         0
+#define ALTERA_TIMER_CONTROL_REG        4
+#define ALTERA_TIMER_PERIODL_REG        8
+#define ALTERA_TIMER_PERIODH_REG        12
+#define ALTERA_TIMER_SNAPL_REG          16
+#define ALTERA_TIMER_SNAPH_REG          20
+
+#define ALTERA_TIMER_CONTROL_ITO_MSK    (0x1)
+#define ALTERA_TIMER_CONTROL_CONT_MSK   (0x2)
+#define ALTERA_TIMER_CONTROL_START_MSK  (0x4)
+#define ALTERA_TIMER_CONTROL_STOP_MSK   (0x8)
+
+struct nios2_timer {
+        void __iomem *base;
+        unsigned long freq;
+        int irq;
+};
+
+struct nios2_clockevent_dev {
+        struct nios2_timer timer;
+        struct clock_event_device ced;
+};
+
+struct nios2_clocksource {
+        struct nios2_timer timer;
+        struct clocksource cs;
+};
+
+static inline struct nios2_clockevent_dev *
+        to_nios2_clkevent(struct clock_event_device *evt)
+{
+        return container_of(evt, struct nios2_clockevent_dev, ced);
+}
+
+static inline struct nios2_clocksource *
+        to_nios2_clksource(struct clocksource *cs)
+{
+        return container_of(cs, struct nios2_clocksource, cs);
+}
+
+static u16 timer_readw(struct nios2_timer *timer, u32 offs)
+{
+        return readw(timer->base + offs);
+}
+
+static void timer_writew(struct nios2_timer *timer, u16 val, u32 offs)
+{
+        writew(val, timer->base + offs);
+}
+
+static inline unsigned long read_timersnapshot(struct nios2_timer *timer)
+{
+        unsigned long count;
+
+        timer_writew(timer, 0, ALTERA_TIMER_SNAPL_REG);
+        count = timer_readw(timer, ALTERA_TIMER_SNAPH_REG) << 16 |
+                timer_readw(timer, ALTERA_TIMER_SNAPL_REG);
+
+        return count;
+}
+
+static cycle_t nios2_timer_read(struct clocksource *cs)
+{
+        struct nios2_clocksource *nios2_cs = to_nios2_clksource(cs);
+        unsigned long flags;
+        u32 count;
+
+        local_irq_save(flags);
+        count = read_timersnapshot(&nios2_cs->timer);
+        local_irq_restore(flags);
+
+        /* Counter is counting down */
+        return ~count;
+}
+
+static struct nios2_clocksource nios2_cs = {
+        .cs = {
+                .name   = "nios2-clksrc",
+                .rating = 250,
+                .read   = nios2_timer_read,
+                .mask   = CLOCKSOURCE_MASK(32),
+                .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+        },
+};
+
+cycles_t get_cycles(void)
+{
+        return nios2_timer_read(&nios2_cs.cs);
+}
+
+static void nios2_timer_start(struct nios2_timer *timer)
+{
+        u16 ctrl;
+
+        ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
+        ctrl |= ALTERA_TIMER_CONTROL_START_MSK;
+        timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
+}
+
+static void nios2_timer_stop(struct nios2_timer *timer)
+{
+        u16 ctrl;
+
+        ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
+        ctrl |= ALTERA_TIMER_CONTROL_STOP_MSK;
+        timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
+}
+
+static void nios2_timer_config(struct nios2_timer *timer, unsigned long period,
+        enum clock_event_mode mode)
+{
+        u16 ctrl;
+
+        /* The timer's actual period is one cycle greater than the value
+         * stored in the period register. */
+         period--;
+
+        ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
+        /* stop counter */
+        timer_writew(timer, ctrl | ALTERA_TIMER_CONTROL_STOP_MSK,
+                ALTERA_TIMER_CONTROL_REG);
+
+        /* write new count */
+        timer_writew(timer, period, ALTERA_TIMER_PERIODL_REG);
+        timer_writew(timer, period >> 16, ALTERA_TIMER_PERIODH_REG);
+
+        ctrl |= ALTERA_TIMER_CONTROL_START_MSK | ALTERA_TIMER_CONTROL_ITO_MSK;
+        if (mode == CLOCK_EVT_MODE_PERIODIC)
+                ctrl |= ALTERA_TIMER_CONTROL_CONT_MSK;
+        else
+                ctrl &= ~ALTERA_TIMER_CONTROL_CONT_MSK;
+        timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
+}
+
+static int nios2_timer_set_next_event(unsigned long delta,
+        struct clock_event_device *evt)
+{
+        struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
+
+        nios2_timer_config(&nios2_ced->timer, delta, evt->mode);
+
+        return 0;
+}
+
+static void nios2_timer_set_mode(enum clock_event_mode mode,
+        struct clock_event_device *evt)
+{
+        unsigned long period;
+        struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
+        struct nios2_timer *timer = &nios2_ced->timer;
+
+        switch (mode) {
+        case CLOCK_EVT_MODE_PERIODIC:
+                period = DIV_ROUND_UP(timer->freq, HZ);
+                nios2_timer_config(timer, period, CLOCK_EVT_MODE_PERIODIC);
+                break;
+        case CLOCK_EVT_MODE_ONESHOT:
+        case CLOCK_EVT_MODE_UNUSED:
+        case CLOCK_EVT_MODE_SHUTDOWN:
+                nios2_timer_stop(timer);
+                break;
+        case CLOCK_EVT_MODE_RESUME:
+                nios2_timer_start(timer);
+                break;
+        }
+}
+
+irqreturn_t timer_interrupt(int irq, void *dev_id)
+{
+        struct clock_event_device *evt = (struct clock_event_device *) dev_id;
+        struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
+
+        /* Clear the interrupt condition */
+        timer_writew(&nios2_ced->timer, 0, ALTERA_TIMER_STATUS_REG);
+        evt->event_handler(evt);
+
+        return IRQ_HANDLED;
+}
+
+static void __init nios2_timer_get_base_and_freq(struct device_node *np,
+                                void __iomem **base, u32 *freq)
+{
+        *base = of_iomap(np, 0);
+        if (!*base)
+                panic("Unable to map reg for %s\n", np->name);
+
+        if (of_property_read_u32(np, "clock-frequency", freq))
+                panic("Unable to get %s clock frequency\n", np->name);
+}
+
+static struct nios2_clockevent_dev nios2_ce = {
+        .ced = {
+                .name = "nios2-clkevent",
+                .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+                .rating = 250,
+                .shift = 32,
+                .set_next_event = nios2_timer_set_next_event,
+                .set_mode = nios2_timer_set_mode,
+        },
+};
+
+static __init void nios2_clockevent_init(struct device_node *timer)
+{
+        void __iomem *iobase;
+        u32 freq;
+        int irq;
+
+        nios2_timer_get_base_and_freq(timer, &iobase, &freq);
+
+        irq = irq_of_parse_and_map(timer, 0);
+        if (irq < 0)
+                panic("Unable to parse timer irq\n");
+
+        nios2_ce.timer.base = iobase;
+        nios2_ce.timer.irq = irq;
+        nios2_ce.timer.freq = freq;
+
+        nios2_ce.ced.cpumask = cpumask_of(0);
+        nios2_ce.ced.irq = irq;
+
+        nios2_timer_stop(&nios2_ce.timer);
+        /* clear pending interrupt */
+        timer_writew(&nios2_ce.timer, 0, ALTERA_TIMER_STATUS_REG);
+
+        if (request_irq(irq, timer_interrupt, IRQF_TIMER, timer->name,
+                &nios2_ce.ced))
+                panic("Unable to setup timer irq\n");
+
+        clockevents_config_and_register(&nios2_ce.ced, freq, 1, ULONG_MAX);
+}
+
+static __init void nios2_clocksource_init(struct device_node *timer)
+{
+        unsigned int ctrl;
+        void __iomem *iobase;
+        u32 freq;
+
+        nios2_timer_get_base_and_freq(timer, &iobase, &freq);
+
+        nios2_cs.timer.base = iobase;
+        nios2_cs.timer.freq = freq;
+
+        clocksource_register_hz(&nios2_cs.cs, freq);
+
+        timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODL_REG);
+        timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODH_REG);
+
+        /* interrupt disable + continuous + start */
+        ctrl = ALTERA_TIMER_CONTROL_CONT_MSK | ALTERA_TIMER_CONTROL_START_MSK;
+        timer_writew(&nios2_cs.timer, ctrl, ALTERA_TIMER_CONTROL_REG);
+
+        /* Calibrate the delay loop directly */
+        lpj_fine = freq / HZ;
+}
+
+/*
+ * The first timer instance will use as a clockevent. If there are two or
+ * more instances, the second one gets used as clocksource and all
+ * others are unused.
+*/
+static void __init nios2_time_init(struct device_node *timer)
+{
+        static int num_called;
+
+        switch (num_called) {
+        case 0:
+                nios2_clockevent_init(timer);
+                break;
+        case 1:
+                nios2_clocksource_init(timer);
+                break;
+        default:
+                break;
+        }
+
+        num_called++;
+}
+
+void read_persistent_clock(struct timespec *ts)
+{
+        ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0);
+        ts->tv_nsec = 0;
+}
+
+void __init time_init(void)
+{
+        clocksource_of_init();
+}
+
+CLOCKSOURCE_OF_DECLARE(nios2_timer, "altr,timer-1.0", nios2_time_init);
diff --git a/arch/nios2/lib/delay.c b/arch/nios2/lib/delay.c
new file mode 100644
index 000000000000..088119cd0cc5
--- /dev/null
+++ b/arch/nios2/lib/delay.c
@@ -0,0 +1,52 @@
+/* Copyright Altera Corporation (C) 2014. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <linux/module.h>
+#include <asm/delay.h>
+#include <asm/param.h>
+#include <asm/processor.h>
+#include <asm/timex.h>
+
+void __delay(unsigned long cycles)
+{
+        cycles_t start = get_cycles();
+
+        while ((get_cycles() - start) < cycles)
+                cpu_relax();
+}
+EXPORT_SYMBOL(__delay);
+
+void __const_udelay(unsigned long xloops)
+{
+        u64 loops;
+
+        loops = (u64)xloops * loops_per_jiffy * HZ;
+
+        __delay(loops >> 32);
+}
+EXPORT_SYMBOL(__const_udelay);
+
+void __udelay(unsigned long usecs)
+{
+        __const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */
+}
+EXPORT_SYMBOL(__udelay);
+
+void __ndelay(unsigned long nsecs)
+{
+        __const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */
+}
+EXPORT_SYMBOL(__ndelay);