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b9dbf951 MD |
1 | /* |
2 | * Emma Mobile Timer Support - STI | |
3 | * | |
4 | * Copyright (C) 2012 Magnus Damm | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
19 | ||
20 | #include <linux/init.h> | |
21 | #include <linux/platform_device.h> | |
22 | #include <linux/spinlock.h> | |
23 | #include <linux/interrupt.h> | |
24 | #include <linux/ioport.h> | |
25 | #include <linux/io.h> | |
26 | #include <linux/clk.h> | |
27 | #include <linux/irq.h> | |
28 | #include <linux/err.h> | |
29 | #include <linux/delay.h> | |
30 | #include <linux/clocksource.h> | |
31 | #include <linux/clockchips.h> | |
32 | #include <linux/slab.h> | |
33 | #include <linux/module.h> | |
34 | ||
35 | enum { USER_CLOCKSOURCE, USER_CLOCKEVENT, USER_NR }; | |
36 | ||
37 | struct em_sti_priv { | |
38 | void __iomem *base; | |
39 | struct clk *clk; | |
40 | struct platform_device *pdev; | |
41 | unsigned int active[USER_NR]; | |
42 | unsigned long rate; | |
43 | raw_spinlock_t lock; | |
44 | struct clock_event_device ced; | |
45 | struct clocksource cs; | |
46 | }; | |
47 | ||
48 | #define STI_CONTROL 0x00 | |
49 | #define STI_COMPA_H 0x10 | |
50 | #define STI_COMPA_L 0x14 | |
51 | #define STI_COMPB_H 0x18 | |
52 | #define STI_COMPB_L 0x1c | |
53 | #define STI_COUNT_H 0x20 | |
54 | #define STI_COUNT_L 0x24 | |
55 | #define STI_COUNT_RAW_H 0x28 | |
56 | #define STI_COUNT_RAW_L 0x2c | |
57 | #define STI_SET_H 0x30 | |
58 | #define STI_SET_L 0x34 | |
59 | #define STI_INTSTATUS 0x40 | |
60 | #define STI_INTRAWSTATUS 0x44 | |
61 | #define STI_INTENSET 0x48 | |
62 | #define STI_INTENCLR 0x4c | |
63 | #define STI_INTFFCLR 0x50 | |
64 | ||
65 | static inline unsigned long em_sti_read(struct em_sti_priv *p, int offs) | |
66 | { | |
67 | return ioread32(p->base + offs); | |
68 | } | |
69 | ||
70 | static inline void em_sti_write(struct em_sti_priv *p, int offs, | |
71 | unsigned long value) | |
72 | { | |
73 | iowrite32(value, p->base + offs); | |
74 | } | |
75 | ||
76 | static int em_sti_enable(struct em_sti_priv *p) | |
77 | { | |
78 | int ret; | |
79 | ||
80 | /* enable clock */ | |
81 | ret = clk_enable(p->clk); | |
82 | if (ret) { | |
83 | dev_err(&p->pdev->dev, "cannot enable clock\n"); | |
84 | return ret; | |
85 | } | |
86 | ||
87 | /* configure channel, periodic mode and maximum timeout */ | |
88 | p->rate = clk_get_rate(p->clk); | |
89 | ||
90 | /* reset the counter */ | |
91 | em_sti_write(p, STI_SET_H, 0x40000000); | |
92 | em_sti_write(p, STI_SET_L, 0x00000000); | |
93 | ||
94 | /* mask and clear pending interrupts */ | |
95 | em_sti_write(p, STI_INTENCLR, 3); | |
96 | em_sti_write(p, STI_INTFFCLR, 3); | |
97 | ||
98 | /* enable updates of counter registers */ | |
99 | em_sti_write(p, STI_CONTROL, 1); | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | static void em_sti_disable(struct em_sti_priv *p) | |
105 | { | |
106 | /* mask interrupts */ | |
107 | em_sti_write(p, STI_INTENCLR, 3); | |
108 | ||
109 | /* stop clock */ | |
110 | clk_disable(p->clk); | |
111 | } | |
112 | ||
113 | static cycle_t em_sti_count(struct em_sti_priv *p) | |
114 | { | |
115 | cycle_t ticks; | |
116 | unsigned long flags; | |
117 | ||
118 | /* the STI hardware buffers the 48-bit count, but to | |
119 | * break it out into two 32-bit access the registers | |
120 | * must be accessed in a certain order. | |
121 | * Always read STI_COUNT_H before STI_COUNT_L. | |
122 | */ | |
123 | raw_spin_lock_irqsave(&p->lock, flags); | |
124 | ticks = (cycle_t)(em_sti_read(p, STI_COUNT_H) & 0xffff) << 32; | |
125 | ticks |= em_sti_read(p, STI_COUNT_L); | |
126 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
127 | ||
128 | return ticks; | |
129 | } | |
130 | ||
131 | static cycle_t em_sti_set_next(struct em_sti_priv *p, cycle_t next) | |
132 | { | |
133 | unsigned long flags; | |
134 | ||
135 | raw_spin_lock_irqsave(&p->lock, flags); | |
136 | ||
137 | /* mask compare A interrupt */ | |
138 | em_sti_write(p, STI_INTENCLR, 1); | |
139 | ||
140 | /* update compare A value */ | |
141 | em_sti_write(p, STI_COMPA_H, next >> 32); | |
142 | em_sti_write(p, STI_COMPA_L, next & 0xffffffff); | |
143 | ||
144 | /* clear compare A interrupt source */ | |
145 | em_sti_write(p, STI_INTFFCLR, 1); | |
146 | ||
147 | /* unmask compare A interrupt */ | |
148 | em_sti_write(p, STI_INTENSET, 1); | |
149 | ||
150 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
151 | ||
152 | return next; | |
153 | } | |
154 | ||
155 | static irqreturn_t em_sti_interrupt(int irq, void *dev_id) | |
156 | { | |
157 | struct em_sti_priv *p = dev_id; | |
158 | ||
159 | p->ced.event_handler(&p->ced); | |
160 | return IRQ_HANDLED; | |
161 | } | |
162 | ||
163 | static int em_sti_start(struct em_sti_priv *p, unsigned int user) | |
164 | { | |
165 | unsigned long flags; | |
166 | int used_before; | |
167 | int ret = 0; | |
168 | ||
169 | raw_spin_lock_irqsave(&p->lock, flags); | |
170 | used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
171 | if (!used_before) | |
172 | ret = em_sti_enable(p); | |
173 | ||
174 | if (!ret) | |
175 | p->active[user] = 1; | |
176 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
177 | ||
178 | return ret; | |
179 | } | |
180 | ||
181 | static void em_sti_stop(struct em_sti_priv *p, unsigned int user) | |
182 | { | |
183 | unsigned long flags; | |
184 | int used_before, used_after; | |
185 | ||
186 | raw_spin_lock_irqsave(&p->lock, flags); | |
187 | used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
188 | p->active[user] = 0; | |
189 | used_after = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
190 | ||
191 | if (used_before && !used_after) | |
192 | em_sti_disable(p); | |
193 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
194 | } | |
195 | ||
196 | static struct em_sti_priv *cs_to_em_sti(struct clocksource *cs) | |
197 | { | |
198 | return container_of(cs, struct em_sti_priv, cs); | |
199 | } | |
200 | ||
201 | static cycle_t em_sti_clocksource_read(struct clocksource *cs) | |
202 | { | |
203 | return em_sti_count(cs_to_em_sti(cs)); | |
204 | } | |
205 | ||
206 | static int em_sti_clocksource_enable(struct clocksource *cs) | |
207 | { | |
208 | int ret; | |
209 | struct em_sti_priv *p = cs_to_em_sti(cs); | |
210 | ||
211 | ret = em_sti_start(p, USER_CLOCKSOURCE); | |
212 | if (!ret) | |
213 | __clocksource_updatefreq_hz(cs, p->rate); | |
214 | return ret; | |
215 | } | |
216 | ||
217 | static void em_sti_clocksource_disable(struct clocksource *cs) | |
218 | { | |
219 | em_sti_stop(cs_to_em_sti(cs), USER_CLOCKSOURCE); | |
220 | } | |
221 | ||
222 | static void em_sti_clocksource_resume(struct clocksource *cs) | |
223 | { | |
224 | em_sti_clocksource_enable(cs); | |
225 | } | |
226 | ||
227 | static int em_sti_register_clocksource(struct em_sti_priv *p) | |
228 | { | |
229 | struct clocksource *cs = &p->cs; | |
230 | ||
231 | memset(cs, 0, sizeof(*cs)); | |
232 | cs->name = dev_name(&p->pdev->dev); | |
233 | cs->rating = 200; | |
234 | cs->read = em_sti_clocksource_read; | |
235 | cs->enable = em_sti_clocksource_enable; | |
236 | cs->disable = em_sti_clocksource_disable; | |
237 | cs->suspend = em_sti_clocksource_disable; | |
238 | cs->resume = em_sti_clocksource_resume; | |
239 | cs->mask = CLOCKSOURCE_MASK(48); | |
240 | cs->flags = CLOCK_SOURCE_IS_CONTINUOUS; | |
241 | ||
242 | dev_info(&p->pdev->dev, "used as clock source\n"); | |
243 | ||
244 | /* Register with dummy 1 Hz value, gets updated in ->enable() */ | |
245 | clocksource_register_hz(cs, 1); | |
246 | return 0; | |
247 | } | |
248 | ||
249 | static struct em_sti_priv *ced_to_em_sti(struct clock_event_device *ced) | |
250 | { | |
251 | return container_of(ced, struct em_sti_priv, ced); | |
252 | } | |
253 | ||
254 | static void em_sti_clock_event_mode(enum clock_event_mode mode, | |
255 | struct clock_event_device *ced) | |
256 | { | |
257 | struct em_sti_priv *p = ced_to_em_sti(ced); | |
258 | ||
259 | /* deal with old setting first */ | |
260 | switch (ced->mode) { | |
261 | case CLOCK_EVT_MODE_ONESHOT: | |
262 | em_sti_stop(p, USER_CLOCKEVENT); | |
263 | break; | |
264 | default: | |
265 | break; | |
266 | } | |
267 | ||
268 | switch (mode) { | |
269 | case CLOCK_EVT_MODE_ONESHOT: | |
270 | dev_info(&p->pdev->dev, "used for oneshot clock events\n"); | |
271 | em_sti_start(p, USER_CLOCKEVENT); | |
272 | clockevents_config(&p->ced, p->rate); | |
273 | break; | |
274 | case CLOCK_EVT_MODE_SHUTDOWN: | |
275 | case CLOCK_EVT_MODE_UNUSED: | |
276 | em_sti_stop(p, USER_CLOCKEVENT); | |
277 | break; | |
278 | default: | |
279 | break; | |
280 | } | |
281 | } | |
282 | ||
283 | static int em_sti_clock_event_next(unsigned long delta, | |
284 | struct clock_event_device *ced) | |
285 | { | |
286 | struct em_sti_priv *p = ced_to_em_sti(ced); | |
287 | cycle_t next; | |
288 | int safe; | |
289 | ||
290 | next = em_sti_set_next(p, em_sti_count(p) + delta); | |
291 | safe = em_sti_count(p) < (next - 1); | |
292 | ||
293 | return !safe; | |
294 | } | |
295 | ||
296 | static void em_sti_register_clockevent(struct em_sti_priv *p) | |
297 | { | |
298 | struct clock_event_device *ced = &p->ced; | |
299 | ||
300 | memset(ced, 0, sizeof(*ced)); | |
301 | ced->name = dev_name(&p->pdev->dev); | |
302 | ced->features = CLOCK_EVT_FEAT_ONESHOT; | |
303 | ced->rating = 200; | |
2199a557 | 304 | ced->cpumask = cpu_possible_mask; |
b9dbf951 MD |
305 | ced->set_next_event = em_sti_clock_event_next; |
306 | ced->set_mode = em_sti_clock_event_mode; | |
307 | ||
308 | dev_info(&p->pdev->dev, "used for clock events\n"); | |
309 | ||
310 | /* Register with dummy 1 Hz value, gets updated in ->set_mode() */ | |
311 | clockevents_config_and_register(ced, 1, 2, 0xffffffff); | |
312 | } | |
313 | ||
1850514b | 314 | static int em_sti_probe(struct platform_device *pdev) |
b9dbf951 MD |
315 | { |
316 | struct em_sti_priv *p; | |
317 | struct resource *res; | |
1745e696 | 318 | int irq; |
b9dbf951 | 319 | |
1745e696 | 320 | p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL); |
b9dbf951 MD |
321 | if (p == NULL) { |
322 | dev_err(&pdev->dev, "failed to allocate driver data\n"); | |
1745e696 | 323 | return -ENOMEM; |
b9dbf951 MD |
324 | } |
325 | ||
326 | p->pdev = pdev; | |
327 | platform_set_drvdata(pdev, p); | |
328 | ||
b9dbf951 MD |
329 | irq = platform_get_irq(pdev, 0); |
330 | if (irq < 0) { | |
331 | dev_err(&pdev->dev, "failed to get irq\n"); | |
1745e696 | 332 | return -EINVAL; |
b9dbf951 MD |
333 | } |
334 | ||
335 | /* map memory, let base point to the STI instance */ | |
1745e696 LP |
336 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
337 | p->base = devm_ioremap_resource(&pdev->dev, res); | |
338 | if (IS_ERR(p->base)) | |
339 | return PTR_ERR(p->base); | |
b9dbf951 MD |
340 | |
341 | /* get hold of clock */ | |
1745e696 | 342 | p->clk = devm_clk_get(&pdev->dev, "sclk"); |
b9dbf951 MD |
343 | if (IS_ERR(p->clk)) { |
344 | dev_err(&pdev->dev, "cannot get clock\n"); | |
1745e696 | 345 | return PTR_ERR(p->clk); |
b9dbf951 MD |
346 | } |
347 | ||
1745e696 LP |
348 | if (devm_request_irq(&pdev->dev, irq, em_sti_interrupt, |
349 | IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, | |
350 | dev_name(&pdev->dev), p)) { | |
b9dbf951 | 351 | dev_err(&pdev->dev, "failed to request low IRQ\n"); |
1745e696 | 352 | return -ENOENT; |
b9dbf951 MD |
353 | } |
354 | ||
355 | raw_spin_lock_init(&p->lock); | |
356 | em_sti_register_clockevent(p); | |
357 | em_sti_register_clocksource(p); | |
358 | return 0; | |
b9dbf951 MD |
359 | } |
360 | ||
1850514b | 361 | static int em_sti_remove(struct platform_device *pdev) |
b9dbf951 MD |
362 | { |
363 | return -EBUSY; /* cannot unregister clockevent and clocksource */ | |
364 | } | |
365 | ||
1850514b | 366 | static const struct of_device_id em_sti_dt_ids[] = { |
fc0830fe MD |
367 | { .compatible = "renesas,em-sti", }, |
368 | {}, | |
369 | }; | |
370 | MODULE_DEVICE_TABLE(of, em_sti_dt_ids); | |
371 | ||
b9dbf951 MD |
372 | static struct platform_driver em_sti_device_driver = { |
373 | .probe = em_sti_probe, | |
1850514b | 374 | .remove = em_sti_remove, |
b9dbf951 MD |
375 | .driver = { |
376 | .name = "em_sti", | |
fc0830fe | 377 | .of_match_table = em_sti_dt_ids, |
b9dbf951 MD |
378 | } |
379 | }; | |
380 | ||
09acc3a1 SH |
381 | static int __init em_sti_init(void) |
382 | { | |
383 | return platform_driver_register(&em_sti_device_driver); | |
384 | } | |
385 | ||
386 | static void __exit em_sti_exit(void) | |
387 | { | |
388 | platform_driver_unregister(&em_sti_device_driver); | |
389 | } | |
390 | ||
391 | subsys_initcall(em_sti_init); | |
392 | module_exit(em_sti_exit); | |
b9dbf951 MD |
393 | |
394 | MODULE_AUTHOR("Magnus Damm"); | |
395 | MODULE_DESCRIPTION("Renesas Emma Mobile STI Timer Driver"); | |
396 | MODULE_LICENSE("GPL v2"); |