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1 | /* |
2 | * Copyright (C) 2013-2014 Altera Corporation | |
3 | * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch> | |
4 | * Copyright (C) 2004 Microtronix Datacom Ltd. | |
5 | * | |
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 | */ | |
10 | ||
05dee9c7 | 11 | #include <linux/export.h> |
4182de9e LFT |
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 ALTERA_TIMER_STATUS_REG 0 | |
23 | #define ALTERA_TIMER_CONTROL_REG 4 | |
24 | #define ALTERA_TIMER_PERIODL_REG 8 | |
25 | #define ALTERA_TIMER_PERIODH_REG 12 | |
26 | #define ALTERA_TIMER_SNAPL_REG 16 | |
27 | #define ALTERA_TIMER_SNAPH_REG 20 | |
28 | ||
29 | #define ALTERA_TIMER_CONTROL_ITO_MSK (0x1) | |
30 | #define ALTERA_TIMER_CONTROL_CONT_MSK (0x2) | |
31 | #define ALTERA_TIMER_CONTROL_START_MSK (0x4) | |
32 | #define ALTERA_TIMER_CONTROL_STOP_MSK (0x8) | |
33 | ||
34 | struct nios2_timer { | |
35 | void __iomem *base; | |
36 | unsigned long freq; | |
4182de9e LFT |
37 | }; |
38 | ||
39 | struct nios2_clockevent_dev { | |
40 | struct nios2_timer timer; | |
41 | struct clock_event_device ced; | |
42 | }; | |
43 | ||
44 | struct nios2_clocksource { | |
45 | struct nios2_timer timer; | |
46 | struct clocksource cs; | |
47 | }; | |
48 | ||
49 | static inline struct nios2_clockevent_dev * | |
50 | to_nios2_clkevent(struct clock_event_device *evt) | |
51 | { | |
52 | return container_of(evt, struct nios2_clockevent_dev, ced); | |
53 | } | |
54 | ||
55 | static inline struct nios2_clocksource * | |
56 | to_nios2_clksource(struct clocksource *cs) | |
57 | { | |
58 | return container_of(cs, struct nios2_clocksource, cs); | |
59 | } | |
60 | ||
61 | static u16 timer_readw(struct nios2_timer *timer, u32 offs) | |
62 | { | |
63 | return readw(timer->base + offs); | |
64 | } | |
65 | ||
66 | static void timer_writew(struct nios2_timer *timer, u16 val, u32 offs) | |
67 | { | |
68 | writew(val, timer->base + offs); | |
69 | } | |
70 | ||
71 | static inline unsigned long read_timersnapshot(struct nios2_timer *timer) | |
72 | { | |
73 | unsigned long count; | |
74 | ||
75 | timer_writew(timer, 0, ALTERA_TIMER_SNAPL_REG); | |
76 | count = timer_readw(timer, ALTERA_TIMER_SNAPH_REG) << 16 | | |
77 | timer_readw(timer, ALTERA_TIMER_SNAPL_REG); | |
78 | ||
79 | return count; | |
80 | } | |
81 | ||
82 | static cycle_t nios2_timer_read(struct clocksource *cs) | |
83 | { | |
84 | struct nios2_clocksource *nios2_cs = to_nios2_clksource(cs); | |
85 | unsigned long flags; | |
86 | u32 count; | |
87 | ||
88 | local_irq_save(flags); | |
89 | count = read_timersnapshot(&nios2_cs->timer); | |
90 | local_irq_restore(flags); | |
91 | ||
92 | /* Counter is counting down */ | |
93 | return ~count; | |
94 | } | |
95 | ||
96 | static struct nios2_clocksource nios2_cs = { | |
97 | .cs = { | |
98 | .name = "nios2-clksrc", | |
99 | .rating = 250, | |
100 | .read = nios2_timer_read, | |
101 | .mask = CLOCKSOURCE_MASK(32), | |
102 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
103 | }, | |
104 | }; | |
105 | ||
106 | cycles_t get_cycles(void) | |
107 | { | |
108 | return nios2_timer_read(&nios2_cs.cs); | |
109 | } | |
05dee9c7 | 110 | EXPORT_SYMBOL(get_cycles); |
4182de9e LFT |
111 | |
112 | static void nios2_timer_start(struct nios2_timer *timer) | |
113 | { | |
114 | u16 ctrl; | |
115 | ||
116 | ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG); | |
117 | ctrl |= ALTERA_TIMER_CONTROL_START_MSK; | |
118 | timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG); | |
119 | } | |
120 | ||
121 | static void nios2_timer_stop(struct nios2_timer *timer) | |
122 | { | |
123 | u16 ctrl; | |
124 | ||
125 | ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG); | |
126 | ctrl |= ALTERA_TIMER_CONTROL_STOP_MSK; | |
127 | timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG); | |
128 | } | |
129 | ||
130 | static void nios2_timer_config(struct nios2_timer *timer, unsigned long period, | |
131 | enum clock_event_mode mode) | |
132 | { | |
133 | u16 ctrl; | |
134 | ||
135 | /* The timer's actual period is one cycle greater than the value | |
136 | * stored in the period register. */ | |
137 | period--; | |
138 | ||
139 | ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG); | |
140 | /* stop counter */ | |
141 | timer_writew(timer, ctrl | ALTERA_TIMER_CONTROL_STOP_MSK, | |
142 | ALTERA_TIMER_CONTROL_REG); | |
143 | ||
144 | /* write new count */ | |
145 | timer_writew(timer, period, ALTERA_TIMER_PERIODL_REG); | |
146 | timer_writew(timer, period >> 16, ALTERA_TIMER_PERIODH_REG); | |
147 | ||
148 | ctrl |= ALTERA_TIMER_CONTROL_START_MSK | ALTERA_TIMER_CONTROL_ITO_MSK; | |
149 | if (mode == CLOCK_EVT_MODE_PERIODIC) | |
150 | ctrl |= ALTERA_TIMER_CONTROL_CONT_MSK; | |
151 | else | |
152 | ctrl &= ~ALTERA_TIMER_CONTROL_CONT_MSK; | |
153 | timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG); | |
154 | } | |
155 | ||
156 | static int nios2_timer_set_next_event(unsigned long delta, | |
157 | struct clock_event_device *evt) | |
158 | { | |
159 | struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt); | |
160 | ||
161 | nios2_timer_config(&nios2_ced->timer, delta, evt->mode); | |
162 | ||
163 | return 0; | |
164 | } | |
165 | ||
166 | static void nios2_timer_set_mode(enum clock_event_mode mode, | |
167 | struct clock_event_device *evt) | |
168 | { | |
169 | unsigned long period; | |
170 | struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt); | |
171 | struct nios2_timer *timer = &nios2_ced->timer; | |
172 | ||
173 | switch (mode) { | |
174 | case CLOCK_EVT_MODE_PERIODIC: | |
175 | period = DIV_ROUND_UP(timer->freq, HZ); | |
176 | nios2_timer_config(timer, period, CLOCK_EVT_MODE_PERIODIC); | |
177 | break; | |
178 | case CLOCK_EVT_MODE_ONESHOT: | |
179 | case CLOCK_EVT_MODE_UNUSED: | |
180 | case CLOCK_EVT_MODE_SHUTDOWN: | |
181 | nios2_timer_stop(timer); | |
182 | break; | |
183 | case CLOCK_EVT_MODE_RESUME: | |
184 | nios2_timer_start(timer); | |
185 | break; | |
186 | } | |
187 | } | |
188 | ||
189 | irqreturn_t timer_interrupt(int irq, void *dev_id) | |
190 | { | |
191 | struct clock_event_device *evt = (struct clock_event_device *) dev_id; | |
192 | struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt); | |
193 | ||
194 | /* Clear the interrupt condition */ | |
195 | timer_writew(&nios2_ced->timer, 0, ALTERA_TIMER_STATUS_REG); | |
196 | evt->event_handler(evt); | |
197 | ||
198 | return IRQ_HANDLED; | |
199 | } | |
200 | ||
201 | static void __init nios2_timer_get_base_and_freq(struct device_node *np, | |
202 | void __iomem **base, u32 *freq) | |
203 | { | |
204 | *base = of_iomap(np, 0); | |
205 | if (!*base) | |
206 | panic("Unable to map reg for %s\n", np->name); | |
207 | ||
208 | if (of_property_read_u32(np, "clock-frequency", freq)) | |
209 | panic("Unable to get %s clock frequency\n", np->name); | |
210 | } | |
211 | ||
212 | static struct nios2_clockevent_dev nios2_ce = { | |
213 | .ced = { | |
214 | .name = "nios2-clkevent", | |
215 | .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, | |
216 | .rating = 250, | |
217 | .shift = 32, | |
218 | .set_next_event = nios2_timer_set_next_event, | |
219 | .set_mode = nios2_timer_set_mode, | |
220 | }, | |
221 | }; | |
222 | ||
223 | static __init void nios2_clockevent_init(struct device_node *timer) | |
224 | { | |
225 | void __iomem *iobase; | |
226 | u32 freq; | |
227 | int irq; | |
228 | ||
229 | nios2_timer_get_base_and_freq(timer, &iobase, &freq); | |
230 | ||
231 | irq = irq_of_parse_and_map(timer, 0); | |
b29438f2 | 232 | if (!irq) |
4182de9e LFT |
233 | panic("Unable to parse timer irq\n"); |
234 | ||
235 | nios2_ce.timer.base = iobase; | |
4182de9e LFT |
236 | nios2_ce.timer.freq = freq; |
237 | ||
238 | nios2_ce.ced.cpumask = cpumask_of(0); | |
239 | nios2_ce.ced.irq = irq; | |
240 | ||
241 | nios2_timer_stop(&nios2_ce.timer); | |
242 | /* clear pending interrupt */ | |
243 | timer_writew(&nios2_ce.timer, 0, ALTERA_TIMER_STATUS_REG); | |
244 | ||
245 | if (request_irq(irq, timer_interrupt, IRQF_TIMER, timer->name, | |
246 | &nios2_ce.ced)) | |
247 | panic("Unable to setup timer irq\n"); | |
248 | ||
249 | clockevents_config_and_register(&nios2_ce.ced, freq, 1, ULONG_MAX); | |
250 | } | |
251 | ||
252 | static __init void nios2_clocksource_init(struct device_node *timer) | |
253 | { | |
254 | unsigned int ctrl; | |
255 | void __iomem *iobase; | |
256 | u32 freq; | |
257 | ||
258 | nios2_timer_get_base_and_freq(timer, &iobase, &freq); | |
259 | ||
260 | nios2_cs.timer.base = iobase; | |
261 | nios2_cs.timer.freq = freq; | |
262 | ||
263 | clocksource_register_hz(&nios2_cs.cs, freq); | |
264 | ||
265 | timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODL_REG); | |
266 | timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODH_REG); | |
267 | ||
268 | /* interrupt disable + continuous + start */ | |
269 | ctrl = ALTERA_TIMER_CONTROL_CONT_MSK | ALTERA_TIMER_CONTROL_START_MSK; | |
270 | timer_writew(&nios2_cs.timer, ctrl, ALTERA_TIMER_CONTROL_REG); | |
271 | ||
272 | /* Calibrate the delay loop directly */ | |
273 | lpj_fine = freq / HZ; | |
274 | } | |
275 | ||
276 | /* | |
277 | * The first timer instance will use as a clockevent. If there are two or | |
278 | * more instances, the second one gets used as clocksource and all | |
279 | * others are unused. | |
280 | */ | |
281 | static void __init nios2_time_init(struct device_node *timer) | |
282 | { | |
283 | static int num_called; | |
284 | ||
285 | switch (num_called) { | |
286 | case 0: | |
287 | nios2_clockevent_init(timer); | |
288 | break; | |
289 | case 1: | |
290 | nios2_clocksource_init(timer); | |
291 | break; | |
292 | default: | |
293 | break; | |
294 | } | |
295 | ||
296 | num_called++; | |
297 | } | |
298 | ||
299 | void read_persistent_clock(struct timespec *ts) | |
300 | { | |
301 | ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0); | |
302 | ts->tv_nsec = 0; | |
303 | } | |
304 | ||
305 | void __init time_init(void) | |
306 | { | |
307 | clocksource_of_init(); | |
308 | } | |
309 | ||
310 | CLOCKSOURCE_OF_DECLARE(nios2_timer, "altr,timer-1.0", nios2_time_init); |