/* * 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/export.h>#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 ALTR_TIMER_COMPATIBLE		"altr,timer-1.0" #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;}; 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 u64 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){	/* Only read timer if it has been initialized */	if (nios2_cs.timer.base)		return nios2_timer_read(&nios2_cs.cs);	return 0;}EXPORT_SYMBOL(get_cycles); 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,			       bool periodic){	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 (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, false); 	return 0;} static int nios2_timer_shutdown(struct clock_event_device *evt){	struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);	struct nios2_timer *timer = &nios2_ced->timer; 	nios2_timer_stop(timer);	return 0;} static int nios2_timer_set_periodic(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; 	period = DIV_ROUND_UP(timer->freq, HZ);	nios2_timer_config(timer, period, true);	return 0;} static int nios2_timer_resume(struct clock_event_device *evt){	struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);	struct nios2_timer *timer = &nios2_ced->timer; 	nios2_timer_start(timer);	return 0;} 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 int __init nios2_timer_get_base_and_freq(struct device_node *np,				void __iomem **base, u32 *freq){	*base = of_iomap(np, 0);	if (!*base) {		pr_crit("Unable to map reg for %pOFn\n", np);		return -ENXIO;	} 	if (of_property_read_u32(np, "clock-frequency", freq)) {		pr_crit("Unable to get %pOFn clock frequency\n", np);		return -EINVAL;	} 	return 0;} 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_state_shutdown = nios2_timer_shutdown,		.set_state_periodic = nios2_timer_set_periodic,		.set_state_oneshot = nios2_timer_shutdown,		.tick_resume = nios2_timer_resume,	},}; static __init int nios2_clockevent_init(struct device_node *timer){	void __iomem *iobase;	u32 freq;	int irq, ret; 	ret = nios2_timer_get_base_and_freq(timer, &iobase, &freq);	if (ret)		return ret; 	irq = irq_of_parse_and_map(timer, 0);	if (!irq) {		pr_crit("Unable to parse timer irq\n");		return -EINVAL;	} 	nios2_ce.timer.base = iobase;	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); 	ret = request_irq(irq, timer_interrupt, IRQF_TIMER, timer->name,			  &nios2_ce.ced);	if (ret) {		pr_crit("Unable to setup timer irq\n");		return ret;	} 	clockevents_config_and_register(&nios2_ce.ced, freq, 1, ULONG_MAX); 	return 0;} static __init int nios2_clocksource_init(struct device_node *timer){	unsigned int ctrl;	void __iomem *iobase;	u32 freq;	int ret; 	ret = nios2_timer_get_base_and_freq(timer, &iobase, &freq);	if (ret)		return ret; 	nios2_cs.timer.base = iobase;	nios2_cs.timer.freq = freq; 	ret = clocksource_register_hz(&nios2_cs.cs, freq);	if (ret)		return ret; 	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; 	return 0;} /* * 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 int __init nios2_time_init(struct device_node *timer){	static int num_called;	int ret; 	switch (num_called) {	case 0:		ret = nios2_clockevent_init(timer);		break;	case 1:		ret = nios2_clocksource_init(timer);		break;	default:		ret = 0;		break;	} 	num_called++; 	return ret;} void read_persistent_clock64(struct timespec64 *ts){	ts->tv_sec = mktime64(2007, 1, 1, 0, 0, 0);	ts->tv_nsec = 0;} void __init time_init(void){	struct device_node *np;	int count = 0; 	for_each_compatible_node(np, NULL,  ALTR_TIMER_COMPATIBLE)		count++; 	if (count < 2)		panic("%d timer is found, it needs 2 timers in system\n", count); 	timer_probe();} TIMER_OF_DECLARE(nios2_timer, ALTR_TIMER_COMPATIBLE, nios2_time_init);