Date:	Wed, 8 Oct 2014 17:29:47 +0800
From:	Ley Foon Tan <lftan@...era.com>
To:	<linux-arch@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-doc@...r.kernel.org>
CC:	Arnd Bergmann <arnd@...db.de>, Ley Foon Tan <lftan@...era.com>,
	<lftan.linux@...il.com>, <cltang@...esourcery.com>
Subject: [PATCH v4 21/29] nios2: Time keeping

Add time keeping code for nios2.

Signed-off-by: Ley Foon Tan <lftan@...era.com>
---
 arch/nios2/include/asm/delay.h |   21 +++
 arch/nios2/include/asm/timex.h |   26 ++++
 arch/nios2/kernel/time.c       |  318 ++++++++++++++++++++++++++++++++++++++++
 arch/nios2/lib/delay.c         |   52 +++++++
 4 files changed, 417 insertions(+), 0 deletions(-)
 create mode 100644 arch/nios2/include/asm/delay.h
 create mode 100644 arch/nios2/include/asm/timex.h
 create mode 100644 arch/nios2/kernel/time.c
 create mode 100644 arch/nios2/lib/delay.c

diff --git a/arch/nios2/include/asm/delay.h b/arch/nios2/include/asm/delay.h
new file mode 100644
index 0000000..098e49b
--- /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 0000000..8996106
--- /dev/null
+++ b/arch/nios2/include/asm/timex.h
@@ -0,0 +1,26 @@
+/* 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);
+
+#define ARCH_HAS_READ_CURRENT_TIMER
+
+#endif
diff --git a/arch/nios2/kernel/time.c b/arch/nios2/kernel/time.c
new file mode 100644
index 0000000..ca51f08
--- /dev/null
+++ b/arch/nios2/kernel/time.c
@@ -0,0 +1,318 @@
+/*
+ * Copyright (C) 2013-2014 Altera Corporation
+ * Copyright (C) 2010 Tobias Klauser <tklauser@...tanz.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/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 irqaction irqaction;
+};
+
+struct nios2_clocksource {
+	struct nios2_timer timer;
+	struct clocksource cs;
+};
+
+struct nios2_clocksource *nios2_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;
+}
+
+cycles_t get_cycles(void)
+{
+	return nios2_timer_read(&nios2_cs->cs);
+}
+
+int read_current_timer(unsigned long *timer_val)
+{
+	*timer_val = (unsigned long) get_cycles();
+	return 0;
+}
+
+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. */
+	if (period)
+		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:
+		nios2_timer_config(timer, ULONG_MAX, CLOCK_EVT_MODE_ONESHOT);
+		break;
+	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 __init void nios2_clockevent_init(struct device_node *timer)
+{
+	struct nios2_clockevent_dev *ce;
+	void __iomem *iobase;
+	u32 freq;
+	int irq;
+
+	ce = kzalloc(sizeof(*ce), GFP_KERNEL);
+	if (!ce)
+		panic("Failed to allocate memory for %s\n", timer->name);
+
+	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");
+
+	ce->timer.base = iobase;
+	ce->timer.irq = irq;
+	ce->timer.freq = freq;
+
+	ce->ced.name = timer->name;
+	ce->ced.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	ce->ced.rating = 250;
+	ce->ced.shift = 32;
+	ce->ced.set_next_event = nios2_timer_set_next_event;
+	ce->ced.set_mode = nios2_timer_set_mode;
+	ce->ced.cpumask = cpumask_of(0);
+	ce->ced.irq = irq;
+
+	ce->irqaction.name = timer->name;
+	ce->irqaction.handler = timer_interrupt;
+	ce->irqaction.dev_id = &ce->ced;
+	ce->irqaction.irq = irq;
+	ce->irqaction.flags = IRQF_TIMER;
+
+	nios2_timer_stop(&ce->timer);
+	/* clear pending interrupt */
+	timer_writew(&ce->timer, 0, ALTERA_TIMER_STATUS_REG);
+
+	if (setup_irq(irq, &ce->irqaction))
+		panic("Unable to setup timer irq\n");
+
+	clockevents_config_and_register(&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_cs = kzalloc(sizeof(*nios2_cs), GFP_KERNEL);
+	if (!nios2_cs)
+		panic("Failed to allocate memory for %s\n", timer->name);
+
+	nios2_timer_get_base_and_freq(timer, &iobase, &freq);
+
+	nios2_cs->timer.base = iobase;
+	nios2_cs->timer.freq = freq;
+
+	nios2_cs->cs.name = timer->name;
+	nios2_cs->cs.rating = 250;
+	nios2_cs->cs.read = nios2_timer_read;
+	nios2_cs->cs.mask = CLOCKSOURCE_MASK(32);
+	nios2_cs->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+	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);
+}
+
+
+static int num_called;
+static void __init nios2_time_init(struct device_node *timer)
+{
+	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 0000000..088119c
--- /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);
-- 
1.7.7.4

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