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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>
21
22#define ALTR_TIMER_COMPATIBLE "altr,timer-1.0"
23
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
30
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)
35
36struct nios2_timer {
37 void __iomem *base;
38 unsigned long freq;
39};
40
41struct nios2_clockevent_dev {
42 struct nios2_timer timer;
43 struct clock_event_device ced;
44};
45
46struct nios2_clocksource {
47 struct nios2_timer timer;
48 struct clocksource cs;
49};
50
51static inline struct nios2_clockevent_dev *
52 to_nios2_clkevent(struct clock_event_device *evt)
53{
54 return container_of(evt, struct nios2_clockevent_dev, ced);
55}
56
57static inline struct nios2_clocksource *
58 to_nios2_clksource(struct clocksource *cs)
59{
60 return container_of(cs, struct nios2_clocksource, cs);
61}
62
63static u16 timer_readw(struct nios2_timer *timer, u32 offs)
64{
65 return readw(timer->base + offs);
66}
67
68static void timer_writew(struct nios2_timer *timer, u16 val, u32 offs)
69{
70 writew(val, timer->base + offs);
71}
72
73static inline unsigned long read_timersnapshot(struct nios2_timer *timer)
74{
75 unsigned long count;
76
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);
80
81 return count;
82}
83
84static cycle_t nios2_timer_read(struct clocksource *cs)
85{
86 struct nios2_clocksource *nios2_cs = to_nios2_clksource(cs);
87 unsigned long flags;
88 u32 count;
89
90 local_irq_save(flags);
91 count = read_timersnapshot(&nios2_cs->timer);
92 local_irq_restore(flags);
93
94
95 return ~count;
96}
97
98static 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,
105 },
106};
107
108cycles_t get_cycles(void)
109{
110 return nios2_timer_read(&nios2_cs.cs);
111}
112EXPORT_SYMBOL(get_cycles);
113
114static void nios2_timer_start(struct nios2_timer *timer)
115{
116 u16 ctrl;
117
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);
121}
122
123static void nios2_timer_stop(struct nios2_timer *timer)
124{
125 u16 ctrl;
126
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);
130}
131
132static void nios2_timer_config(struct nios2_timer *timer, unsigned long period,
133 bool periodic)
134{
135 u16 ctrl;
136
137
138
139 period--;
140
141 ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
142
143 timer_writew(timer, ctrl | ALTERA_TIMER_CONTROL_STOP_MSK,
144 ALTERA_TIMER_CONTROL_REG);
145
146
147 timer_writew(timer, period, ALTERA_TIMER_PERIODL_REG);
148 timer_writew(timer, period >> 16, ALTERA_TIMER_PERIODH_REG);
149
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);
156}
157
158static int nios2_timer_set_next_event(unsigned long delta,
159 struct clock_event_device *evt)
160{
161 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
162
163 nios2_timer_config(&nios2_ced->timer, delta, false);
164
165 return 0;
166}
167
168static int nios2_timer_shutdown(struct clock_event_device *evt)
169{
170 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
171 struct nios2_timer *timer = &nios2_ced->timer;
172
173 nios2_timer_stop(timer);
174 return 0;
175}
176
177static int nios2_timer_set_periodic(struct clock_event_device *evt)
178{
179 unsigned long period;
180 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
181 struct nios2_timer *timer = &nios2_ced->timer;
182
183 period = DIV_ROUND_UP(timer->freq, HZ);
184 nios2_timer_config(timer, period, true);
185 return 0;
186}
187
188static int nios2_timer_resume(struct clock_event_device *evt)
189{
190 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
191 struct nios2_timer *timer = &nios2_ced->timer;
192
193 nios2_timer_start(timer);
194 return 0;
195}
196
197irqreturn_t timer_interrupt(int irq, void *dev_id)
198{
199 struct clock_event_device *evt = (struct clock_event_device *) dev_id;
200 struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
201
202
203 timer_writew(&nios2_ced->timer, 0, ALTERA_TIMER_STATUS_REG);
204 evt->event_handler(evt);
205
206 return IRQ_HANDLED;
207}
208
209static void __init nios2_timer_get_base_and_freq(struct device_node *np,
210 void __iomem **base, u32 *freq)
211{
212 *base = of_iomap(np, 0);
213 if (!*base)
214 panic("Unable to map reg for %s\n", np->name);
215
216 if (of_property_read_u32(np, "clock-frequency", freq))
217 panic("Unable to get %s clock frequency\n", np->name);
218}
219
220static 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,
231 },
232};
233
234static __init void nios2_clockevent_init(struct device_node *timer)
235{
236 void __iomem *iobase;
237 u32 freq;
238 int irq;
239
240 nios2_timer_get_base_and_freq(timer, &iobase, &freq);
241
242 irq = irq_of_parse_and_map(timer, 0);
243 if (!irq)
244 panic("Unable to parse timer irq\n");
245
246 nios2_ce.timer.base = iobase;
247 nios2_ce.timer.freq = freq;
248
249 nios2_ce.ced.cpumask = cpumask_of(0);
250 nios2_ce.ced.irq = irq;
251
252 nios2_timer_stop(&nios2_ce.timer);
253
254 timer_writew(&nios2_ce.timer, 0, ALTERA_TIMER_STATUS_REG);
255
256 if (request_irq(irq, timer_interrupt, IRQF_TIMER, timer->name,
257 &nios2_ce.ced))
258 panic("Unable to setup timer irq\n");
259
260 clockevents_config_and_register(&nios2_ce.ced, freq, 1, ULONG_MAX);
261}
262
263static __init void nios2_clocksource_init(struct device_node *timer)
264{
265 unsigned int ctrl;
266 void __iomem *iobase;
267 u32 freq;
268
269 nios2_timer_get_base_and_freq(timer, &iobase, &freq);
270
271 nios2_cs.timer.base = iobase;
272 nios2_cs.timer.freq = freq;
273
274 clocksource_register_hz(&nios2_cs.cs, freq);
275
276 timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODL_REG);
277 timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODH_REG);
278
279
280 ctrl = ALTERA_TIMER_CONTROL_CONT_MSK | ALTERA_TIMER_CONTROL_START_MSK;
281 timer_writew(&nios2_cs.timer, ctrl, ALTERA_TIMER_CONTROL_REG);
282
283
284 lpj_fine = freq / HZ;
285}
286
287
288
289
290
291
292static void __init nios2_time_init(struct device_node *timer)
293{
294 static int num_called;
295
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;
305 }
306
307 num_called++;
308}
309
310void read_persistent_clock(struct timespec *ts)
311{
312 ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0);
313 ts->tv_nsec = 0;
314}
315
316void __init time_init(void)
317{
318 struct device_node *np;
319 int count = 0;
320
321 for_each_compatible_node(np, NULL, ALTR_TIMER_COMPATIBLE)
322 count++;
323
324 if (count < 2)
325 panic("%d timer is found, it needs 2 timers in system\n", count);
326
327 clocksource_of_init();
328}
329
330CLOCKSOURCE_OF_DECLARE(nios2_timer, ALTR_TIMER_COMPATIBLE, nios2_time_init);
331
