Linux 4.6-rc6
[linux/fpc-iii.git] / arch / nios2 / kernel / time.c
blobe835dda2bfe2d5342f0b87f763476ebd9ae81875
1 /*
2 * Copyright (C) 2013-2014 Altera Corporation
3 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
4 * Copyright (C) 2004 Microtronix Datacom Ltd.
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
11 #include <linux/export.h>
12 #include <linux/interrupt.h>
13 #include <linux/clockchips.h>
14 #include <linux/clocksource.h>
15 #include <linux/delay.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/of_irq.h>
19 #include <linux/io.h>
20 #include <linux/slab.h>
22 #define ALTR_TIMER_COMPATIBLE "altr,timer-1.0"
24 #define ALTERA_TIMER_STATUS_REG 0
25 #define ALTERA_TIMER_CONTROL_REG 4
26 #define ALTERA_TIMER_PERIODL_REG 8
27 #define ALTERA_TIMER_PERIODH_REG 12
28 #define ALTERA_TIMER_SNAPL_REG 16
29 #define ALTERA_TIMER_SNAPH_REG 20
31 #define ALTERA_TIMER_CONTROL_ITO_MSK (0x1)
32 #define ALTERA_TIMER_CONTROL_CONT_MSK (0x2)
33 #define ALTERA_TIMER_CONTROL_START_MSK (0x4)
34 #define ALTERA_TIMER_CONTROL_STOP_MSK (0x8)
36 struct nios2_timer {
37 void __iomem *base;
38 unsigned long freq;
41 struct nios2_clockevent_dev {
42 struct nios2_timer timer;
43 struct clock_event_device ced;
46 struct nios2_clocksource {
47 struct nios2_timer timer;
48 struct clocksource cs;
51 static inline struct nios2_clockevent_dev *
52 to_nios2_clkevent(struct clock_event_device *evt)
54 return container_of(evt, struct nios2_clockevent_dev, ced);
57 static inline struct nios2_clocksource *
58 to_nios2_clksource(struct clocksource *cs)
60 return container_of(cs, struct nios2_clocksource, cs);
63 static u16 timer_readw(struct nios2_timer *timer, u32 offs)
65 return readw(timer->base + offs);
68 static void timer_writew(struct nios2_timer *timer, u16 val, u32 offs)
70 writew(val, timer->base + offs);
73 static inline unsigned long read_timersnapshot(struct nios2_timer *timer)
75 unsigned long count;
77 timer_writew(timer, 0, ALTERA_TIMER_SNAPL_REG);
78 count = timer_readw(timer, ALTERA_TIMER_SNAPH_REG) << 16 |
79 timer_readw(timer, ALTERA_TIMER_SNAPL_REG);
81 return count;
84 static cycle_t nios2_timer_read(struct clocksource *cs)
86 struct nios2_clocksource *nios2_cs = to_nios2_clksource(cs);
87 unsigned long flags;
88 u32 count;
90 local_irq_save(flags);
91 count = read_timersnapshot(&nios2_cs->timer);
92 local_irq_restore(flags);
94 /* Counter is counting down */
95 return ~count;
98 static struct nios2_clocksource nios2_cs = {
99 .cs = {
100 .name = "nios2-clksrc",
101 .rating = 250,
102 .read = nios2_timer_read,
103 .mask = CLOCKSOURCE_MASK(32),
104 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
108 cycles_t get_cycles(void)
110 return nios2_timer_read(&nios2_cs.cs);
112 EXPORT_SYMBOL(get_cycles);
114 static void nios2_timer_start(struct nios2_timer *timer)
116 u16 ctrl;
118 ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
119 ctrl |= ALTERA_TIMER_CONTROL_START_MSK;
120 timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
123 static void nios2_timer_stop(struct nios2_timer *timer)
125 u16 ctrl;
127 ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
128 ctrl |= ALTERA_TIMER_CONTROL_STOP_MSK;
129 timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
132 static void nios2_timer_config(struct nios2_timer *timer, unsigned long period,
133 bool periodic)
135 u16 ctrl;
137 /* The timer's actual period is one cycle greater than the value
138 * stored in the period register. */
139 period--;
141 ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
142 /* stop counter */
143 timer_writew(timer, ctrl | ALTERA_TIMER_CONTROL_STOP_MSK,
144 ALTERA_TIMER_CONTROL_REG);
146 /* write new count */
147 timer_writew(timer, period, ALTERA_TIMER_PERIODL_REG);
148 timer_writew(timer, period >> 16, ALTERA_TIMER_PERIODH_REG);
150 ctrl |= ALTERA_TIMER_CONTROL_START_MSK | ALTERA_TIMER_CONTROL_ITO_MSK;
151 if (periodic)
152 ctrl |= ALTERA_TIMER_CONTROL_CONT_MSK;
153 else
154 ctrl &= ~ALTERA_TIMER_CONTROL_CONT_MSK;
155 timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
158 static int nios2_timer_set_next_event(unsigned long delta,
159 struct clock_event_device *evt)
161 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
163 nios2_timer_config(&nios2_ced->timer, delta, false);
165 return 0;
168 static int nios2_timer_shutdown(struct clock_event_device *evt)
170 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
171 struct nios2_timer *timer = &nios2_ced->timer;
173 nios2_timer_stop(timer);
174 return 0;
177 static int nios2_timer_set_periodic(struct clock_event_device *evt)
179 unsigned long period;
180 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
181 struct nios2_timer *timer = &nios2_ced->timer;
183 period = DIV_ROUND_UP(timer->freq, HZ);
184 nios2_timer_config(timer, period, true);
185 return 0;
188 static int nios2_timer_resume(struct clock_event_device *evt)
190 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
191 struct nios2_timer *timer = &nios2_ced->timer;
193 nios2_timer_start(timer);
194 return 0;
197 irqreturn_t timer_interrupt(int irq, void *dev_id)
199 struct clock_event_device *evt = (struct clock_event_device *) dev_id;
200 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
202 /* Clear the interrupt condition */
203 timer_writew(&nios2_ced->timer, 0, ALTERA_TIMER_STATUS_REG);
204 evt->event_handler(evt);
206 return IRQ_HANDLED;
209 static void __init nios2_timer_get_base_and_freq(struct device_node *np,
210 void __iomem **base, u32 *freq)
212 *base = of_iomap(np, 0);
213 if (!*base)
214 panic("Unable to map reg for %s\n", np->name);
216 if (of_property_read_u32(np, "clock-frequency", freq))
217 panic("Unable to get %s clock frequency\n", np->name);
220 static struct nios2_clockevent_dev nios2_ce = {
221 .ced = {
222 .name = "nios2-clkevent",
223 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
224 .rating = 250,
225 .shift = 32,
226 .set_next_event = nios2_timer_set_next_event,
227 .set_state_shutdown = nios2_timer_shutdown,
228 .set_state_periodic = nios2_timer_set_periodic,
229 .set_state_oneshot = nios2_timer_shutdown,
230 .tick_resume = nios2_timer_resume,
234 static __init void nios2_clockevent_init(struct device_node *timer)
236 void __iomem *iobase;
237 u32 freq;
238 int irq;
240 nios2_timer_get_base_and_freq(timer, &iobase, &freq);
242 irq = irq_of_parse_and_map(timer, 0);
243 if (!irq)
244 panic("Unable to parse timer irq\n");
246 nios2_ce.timer.base = iobase;
247 nios2_ce.timer.freq = freq;
249 nios2_ce.ced.cpumask = cpumask_of(0);
250 nios2_ce.ced.irq = irq;
252 nios2_timer_stop(&nios2_ce.timer);
253 /* clear pending interrupt */
254 timer_writew(&nios2_ce.timer, 0, ALTERA_TIMER_STATUS_REG);
256 if (request_irq(irq, timer_interrupt, IRQF_TIMER, timer->name,
257 &nios2_ce.ced))
258 panic("Unable to setup timer irq\n");
260 clockevents_config_and_register(&nios2_ce.ced, freq, 1, ULONG_MAX);
263 static __init void nios2_clocksource_init(struct device_node *timer)
265 unsigned int ctrl;
266 void __iomem *iobase;
267 u32 freq;
269 nios2_timer_get_base_and_freq(timer, &iobase, &freq);
271 nios2_cs.timer.base = iobase;
272 nios2_cs.timer.freq = freq;
274 clocksource_register_hz(&nios2_cs.cs, freq);
276 timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODL_REG);
277 timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODH_REG);
279 /* interrupt disable + continuous + start */
280 ctrl = ALTERA_TIMER_CONTROL_CONT_MSK | ALTERA_TIMER_CONTROL_START_MSK;
281 timer_writew(&nios2_cs.timer, ctrl, ALTERA_TIMER_CONTROL_REG);
283 /* Calibrate the delay loop directly */
284 lpj_fine = freq / HZ;
288 * The first timer instance will use as a clockevent. If there are two or
289 * more instances, the second one gets used as clocksource and all
290 * others are unused.
292 static void __init nios2_time_init(struct device_node *timer)
294 static int num_called;
296 switch (num_called) {
297 case 0:
298 nios2_clockevent_init(timer);
299 break;
300 case 1:
301 nios2_clocksource_init(timer);
302 break;
303 default:
304 break;
307 num_called++;
310 void read_persistent_clock(struct timespec *ts)
312 ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0);
313 ts->tv_nsec = 0;
316 void __init time_init(void)
318 struct device_node *np;
319 int count = 0;
321 for_each_compatible_node(np, NULL, ALTR_TIMER_COMPATIBLE)
322 count++;
324 if (count < 2)
325 panic("%d timer is found, it needs 2 timers in system\n", count);
327 clocksource_probe();
330 CLOCKSOURCE_OF_DECLARE(nios2_timer, ALTR_TIMER_COMPATIBLE, nios2_time_init);