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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 */ | |
3814ae09 | 81 | ret = clk_enable(p->clk); |
b9dbf951 MD |
82 | if (ret) { |
83 | dev_err(&p->pdev->dev, "cannot enable clock\n"); | |
84 | return ret; | |
85 | } | |
86 | ||
b9dbf951 MD |
87 | /* reset the counter */ |
88 | em_sti_write(p, STI_SET_H, 0x40000000); | |
89 | em_sti_write(p, STI_SET_L, 0x00000000); | |
90 | ||
91 | /* mask and clear pending interrupts */ | |
92 | em_sti_write(p, STI_INTENCLR, 3); | |
93 | em_sti_write(p, STI_INTFFCLR, 3); | |
94 | ||
95 | /* enable updates of counter registers */ | |
96 | em_sti_write(p, STI_CONTROL, 1); | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | static void em_sti_disable(struct em_sti_priv *p) | |
102 | { | |
103 | /* mask interrupts */ | |
104 | em_sti_write(p, STI_INTENCLR, 3); | |
105 | ||
106 | /* stop clock */ | |
3814ae09 | 107 | clk_disable(p->clk); |
b9dbf951 MD |
108 | } |
109 | ||
a5a1d1c2 | 110 | static u64 em_sti_count(struct em_sti_priv *p) |
b9dbf951 | 111 | { |
a5a1d1c2 | 112 | u64 ticks; |
b9dbf951 MD |
113 | unsigned long flags; |
114 | ||
115 | /* the STI hardware buffers the 48-bit count, but to | |
116 | * break it out into two 32-bit access the registers | |
117 | * must be accessed in a certain order. | |
118 | * Always read STI_COUNT_H before STI_COUNT_L. | |
119 | */ | |
120 | raw_spin_lock_irqsave(&p->lock, flags); | |
a5a1d1c2 | 121 | ticks = (u64)(em_sti_read(p, STI_COUNT_H) & 0xffff) << 32; |
b9dbf951 MD |
122 | ticks |= em_sti_read(p, STI_COUNT_L); |
123 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
124 | ||
125 | return ticks; | |
126 | } | |
127 | ||
a5a1d1c2 | 128 | static u64 em_sti_set_next(struct em_sti_priv *p, u64 next) |
b9dbf951 MD |
129 | { |
130 | unsigned long flags; | |
131 | ||
132 | raw_spin_lock_irqsave(&p->lock, flags); | |
133 | ||
134 | /* mask compare A interrupt */ | |
135 | em_sti_write(p, STI_INTENCLR, 1); | |
136 | ||
137 | /* update compare A value */ | |
138 | em_sti_write(p, STI_COMPA_H, next >> 32); | |
139 | em_sti_write(p, STI_COMPA_L, next & 0xffffffff); | |
140 | ||
141 | /* clear compare A interrupt source */ | |
142 | em_sti_write(p, STI_INTFFCLR, 1); | |
143 | ||
144 | /* unmask compare A interrupt */ | |
145 | em_sti_write(p, STI_INTENSET, 1); | |
146 | ||
147 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
148 | ||
149 | return next; | |
150 | } | |
151 | ||
152 | static irqreturn_t em_sti_interrupt(int irq, void *dev_id) | |
153 | { | |
154 | struct em_sti_priv *p = dev_id; | |
155 | ||
156 | p->ced.event_handler(&p->ced); | |
157 | return IRQ_HANDLED; | |
158 | } | |
159 | ||
160 | static int em_sti_start(struct em_sti_priv *p, unsigned int user) | |
161 | { | |
162 | unsigned long flags; | |
163 | int used_before; | |
164 | int ret = 0; | |
165 | ||
166 | raw_spin_lock_irqsave(&p->lock, flags); | |
167 | used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
168 | if (!used_before) | |
169 | ret = em_sti_enable(p); | |
170 | ||
171 | if (!ret) | |
172 | p->active[user] = 1; | |
173 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
174 | ||
175 | return ret; | |
176 | } | |
177 | ||
178 | static void em_sti_stop(struct em_sti_priv *p, unsigned int user) | |
179 | { | |
180 | unsigned long flags; | |
181 | int used_before, used_after; | |
182 | ||
183 | raw_spin_lock_irqsave(&p->lock, flags); | |
184 | used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
185 | p->active[user] = 0; | |
186 | used_after = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
187 | ||
188 | if (used_before && !used_after) | |
189 | em_sti_disable(p); | |
190 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
191 | } | |
192 | ||
193 | static struct em_sti_priv *cs_to_em_sti(struct clocksource *cs) | |
194 | { | |
195 | return container_of(cs, struct em_sti_priv, cs); | |
196 | } | |
197 | ||
a5a1d1c2 | 198 | static u64 em_sti_clocksource_read(struct clocksource *cs) |
b9dbf951 MD |
199 | { |
200 | return em_sti_count(cs_to_em_sti(cs)); | |
201 | } | |
202 | ||
203 | static int em_sti_clocksource_enable(struct clocksource *cs) | |
204 | { | |
b9dbf951 MD |
205 | struct em_sti_priv *p = cs_to_em_sti(cs); |
206 | ||
4e53aa2f | 207 | return em_sti_start(p, USER_CLOCKSOURCE); |
b9dbf951 MD |
208 | } |
209 | ||
210 | static void em_sti_clocksource_disable(struct clocksource *cs) | |
211 | { | |
212 | em_sti_stop(cs_to_em_sti(cs), USER_CLOCKSOURCE); | |
213 | } | |
214 | ||
215 | static void em_sti_clocksource_resume(struct clocksource *cs) | |
216 | { | |
217 | em_sti_clocksource_enable(cs); | |
218 | } | |
219 | ||
220 | static int em_sti_register_clocksource(struct em_sti_priv *p) | |
221 | { | |
222 | struct clocksource *cs = &p->cs; | |
223 | ||
b9dbf951 MD |
224 | cs->name = dev_name(&p->pdev->dev); |
225 | cs->rating = 200; | |
226 | cs->read = em_sti_clocksource_read; | |
227 | cs->enable = em_sti_clocksource_enable; | |
228 | cs->disable = em_sti_clocksource_disable; | |
229 | cs->suspend = em_sti_clocksource_disable; | |
230 | cs->resume = em_sti_clocksource_resume; | |
231 | cs->mask = CLOCKSOURCE_MASK(48); | |
232 | cs->flags = CLOCK_SOURCE_IS_CONTINUOUS; | |
233 | ||
234 | dev_info(&p->pdev->dev, "used as clock source\n"); | |
235 | ||
4e53aa2f | 236 | clocksource_register_hz(cs, p->rate); |
b9dbf951 MD |
237 | return 0; |
238 | } | |
239 | ||
240 | static struct em_sti_priv *ced_to_em_sti(struct clock_event_device *ced) | |
241 | { | |
242 | return container_of(ced, struct em_sti_priv, ced); | |
243 | } | |
244 | ||
75f94061 | 245 | static int em_sti_clock_event_shutdown(struct clock_event_device *ced) |
b9dbf951 MD |
246 | { |
247 | struct em_sti_priv *p = ced_to_em_sti(ced); | |
75f94061 VK |
248 | em_sti_stop(p, USER_CLOCKEVENT); |
249 | return 0; | |
250 | } | |
b9dbf951 | 251 | |
75f94061 VK |
252 | static int em_sti_clock_event_set_oneshot(struct clock_event_device *ced) |
253 | { | |
254 | struct em_sti_priv *p = ced_to_em_sti(ced); | |
b9dbf951 | 255 | |
75f94061 VK |
256 | dev_info(&p->pdev->dev, "used for oneshot clock events\n"); |
257 | em_sti_start(p, USER_CLOCKEVENT); | |
75f94061 | 258 | return 0; |
b9dbf951 MD |
259 | } |
260 | ||
261 | static int em_sti_clock_event_next(unsigned long delta, | |
262 | struct clock_event_device *ced) | |
263 | { | |
264 | struct em_sti_priv *p = ced_to_em_sti(ced); | |
a5a1d1c2 | 265 | u64 next; |
b9dbf951 MD |
266 | int safe; |
267 | ||
268 | next = em_sti_set_next(p, em_sti_count(p) + delta); | |
269 | safe = em_sti_count(p) < (next - 1); | |
270 | ||
271 | return !safe; | |
272 | } | |
273 | ||
274 | static void em_sti_register_clockevent(struct em_sti_priv *p) | |
275 | { | |
276 | struct clock_event_device *ced = &p->ced; | |
277 | ||
b9dbf951 MD |
278 | ced->name = dev_name(&p->pdev->dev); |
279 | ced->features = CLOCK_EVT_FEAT_ONESHOT; | |
280 | ced->rating = 200; | |
2199a557 | 281 | ced->cpumask = cpu_possible_mask; |
b9dbf951 | 282 | ced->set_next_event = em_sti_clock_event_next; |
75f94061 VK |
283 | ced->set_state_shutdown = em_sti_clock_event_shutdown; |
284 | ced->set_state_oneshot = em_sti_clock_event_set_oneshot; | |
b9dbf951 MD |
285 | |
286 | dev_info(&p->pdev->dev, "used for clock events\n"); | |
287 | ||
4e53aa2f | 288 | clockevents_config_and_register(ced, p->rate, 2, 0xffffffff); |
b9dbf951 MD |
289 | } |
290 | ||
1850514b | 291 | static int em_sti_probe(struct platform_device *pdev) |
b9dbf951 MD |
292 | { |
293 | struct em_sti_priv *p; | |
294 | struct resource *res; | |
1745e696 | 295 | int irq; |
3814ae09 | 296 | int ret; |
b9dbf951 | 297 | |
1745e696 | 298 | p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL); |
39dd5677 | 299 | if (p == NULL) |
1745e696 | 300 | return -ENOMEM; |
b9dbf951 MD |
301 | |
302 | p->pdev = pdev; | |
303 | platform_set_drvdata(pdev, p); | |
304 | ||
b9dbf951 MD |
305 | irq = platform_get_irq(pdev, 0); |
306 | if (irq < 0) { | |
307 | dev_err(&pdev->dev, "failed to get irq\n"); | |
5c23a558 | 308 | return irq; |
b9dbf951 MD |
309 | } |
310 | ||
311 | /* map memory, let base point to the STI instance */ | |
1745e696 LP |
312 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
313 | p->base = devm_ioremap_resource(&pdev->dev, res); | |
314 | if (IS_ERR(p->base)) | |
315 | return PTR_ERR(p->base); | |
b9dbf951 | 316 | |
5c23a558 GS |
317 | ret = devm_request_irq(&pdev->dev, irq, em_sti_interrupt, |
318 | IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, | |
319 | dev_name(&pdev->dev), p); | |
320 | if (ret) { | |
3814ae09 | 321 | dev_err(&pdev->dev, "failed to request low IRQ\n"); |
5c23a558 | 322 | return ret; |
3814ae09 NS |
323 | } |
324 | ||
b9dbf951 | 325 | /* get hold of clock */ |
1745e696 | 326 | p->clk = devm_clk_get(&pdev->dev, "sclk"); |
b9dbf951 MD |
327 | if (IS_ERR(p->clk)) { |
328 | dev_err(&pdev->dev, "cannot get clock\n"); | |
1745e696 | 329 | return PTR_ERR(p->clk); |
b9dbf951 MD |
330 | } |
331 | ||
3814ae09 NS |
332 | ret = clk_prepare(p->clk); |
333 | if (ret < 0) { | |
334 | dev_err(&pdev->dev, "cannot prepare clock\n"); | |
335 | return ret; | |
b9dbf951 MD |
336 | } |
337 | ||
4e53aa2f NS |
338 | ret = clk_enable(p->clk); |
339 | if (ret < 0) { | |
340 | dev_err(&p->pdev->dev, "cannot enable clock\n"); | |
341 | clk_unprepare(p->clk); | |
342 | return ret; | |
343 | } | |
344 | p->rate = clk_get_rate(p->clk); | |
345 | clk_disable(p->clk); | |
346 | ||
b9dbf951 MD |
347 | raw_spin_lock_init(&p->lock); |
348 | em_sti_register_clockevent(p); | |
349 | em_sti_register_clocksource(p); | |
350 | return 0; | |
b9dbf951 MD |
351 | } |
352 | ||
1850514b | 353 | static int em_sti_remove(struct platform_device *pdev) |
b9dbf951 MD |
354 | { |
355 | return -EBUSY; /* cannot unregister clockevent and clocksource */ | |
356 | } | |
357 | ||
1850514b | 358 | static const struct of_device_id em_sti_dt_ids[] = { |
fc0830fe MD |
359 | { .compatible = "renesas,em-sti", }, |
360 | {}, | |
361 | }; | |
362 | MODULE_DEVICE_TABLE(of, em_sti_dt_ids); | |
363 | ||
b9dbf951 MD |
364 | static struct platform_driver em_sti_device_driver = { |
365 | .probe = em_sti_probe, | |
1850514b | 366 | .remove = em_sti_remove, |
b9dbf951 MD |
367 | .driver = { |
368 | .name = "em_sti", | |
fc0830fe | 369 | .of_match_table = em_sti_dt_ids, |
b9dbf951 MD |
370 | } |
371 | }; | |
372 | ||
09acc3a1 SH |
373 | static int __init em_sti_init(void) |
374 | { | |
375 | return platform_driver_register(&em_sti_device_driver); | |
376 | } | |
377 | ||
378 | static void __exit em_sti_exit(void) | |
379 | { | |
380 | platform_driver_unregister(&em_sti_device_driver); | |
381 | } | |
382 | ||
383 | subsys_initcall(em_sti_init); | |
384 | module_exit(em_sti_exit); | |
b9dbf951 MD |
385 | |
386 | MODULE_AUTHOR("Magnus Damm"); | |
387 | MODULE_DESCRIPTION("Renesas Emma Mobile STI Timer Driver"); | |
388 | MODULE_LICENSE("GPL v2"); |