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0b712183 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
b9dbf951 MD |
2 | /* |
3 | * Emma Mobile Timer Support - STI | |
4 | * | |
5 | * Copyright (C) 2012 Magnus Damm | |
b9dbf951 MD |
6 | */ |
7 | ||
8 | #include <linux/init.h> | |
9 | #include <linux/platform_device.h> | |
10 | #include <linux/spinlock.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/ioport.h> | |
13 | #include <linux/io.h> | |
14 | #include <linux/clk.h> | |
15 | #include <linux/irq.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/delay.h> | |
18 | #include <linux/clocksource.h> | |
19 | #include <linux/clockchips.h> | |
20 | #include <linux/slab.h> | |
21 | #include <linux/module.h> | |
22 | ||
23 | enum { USER_CLOCKSOURCE, USER_CLOCKEVENT, USER_NR }; | |
24 | ||
25 | struct em_sti_priv { | |
26 | void __iomem *base; | |
27 | struct clk *clk; | |
28 | struct platform_device *pdev; | |
29 | unsigned int active[USER_NR]; | |
30 | unsigned long rate; | |
31 | raw_spinlock_t lock; | |
32 | struct clock_event_device ced; | |
33 | struct clocksource cs; | |
34 | }; | |
35 | ||
36 | #define STI_CONTROL 0x00 | |
37 | #define STI_COMPA_H 0x10 | |
38 | #define STI_COMPA_L 0x14 | |
39 | #define STI_COMPB_H 0x18 | |
40 | #define STI_COMPB_L 0x1c | |
41 | #define STI_COUNT_H 0x20 | |
42 | #define STI_COUNT_L 0x24 | |
43 | #define STI_COUNT_RAW_H 0x28 | |
44 | #define STI_COUNT_RAW_L 0x2c | |
45 | #define STI_SET_H 0x30 | |
46 | #define STI_SET_L 0x34 | |
47 | #define STI_INTSTATUS 0x40 | |
48 | #define STI_INTRAWSTATUS 0x44 | |
49 | #define STI_INTENSET 0x48 | |
50 | #define STI_INTENCLR 0x4c | |
51 | #define STI_INTFFCLR 0x50 | |
52 | ||
53 | static inline unsigned long em_sti_read(struct em_sti_priv *p, int offs) | |
54 | { | |
55 | return ioread32(p->base + offs); | |
56 | } | |
57 | ||
58 | static inline void em_sti_write(struct em_sti_priv *p, int offs, | |
59 | unsigned long value) | |
60 | { | |
61 | iowrite32(value, p->base + offs); | |
62 | } | |
63 | ||
64 | static int em_sti_enable(struct em_sti_priv *p) | |
65 | { | |
66 | int ret; | |
67 | ||
68 | /* enable clock */ | |
3814ae09 | 69 | ret = clk_enable(p->clk); |
b9dbf951 MD |
70 | if (ret) { |
71 | dev_err(&p->pdev->dev, "cannot enable clock\n"); | |
72 | return ret; | |
73 | } | |
74 | ||
b9dbf951 MD |
75 | /* reset the counter */ |
76 | em_sti_write(p, STI_SET_H, 0x40000000); | |
77 | em_sti_write(p, STI_SET_L, 0x00000000); | |
78 | ||
79 | /* mask and clear pending interrupts */ | |
80 | em_sti_write(p, STI_INTENCLR, 3); | |
81 | em_sti_write(p, STI_INTFFCLR, 3); | |
82 | ||
83 | /* enable updates of counter registers */ | |
84 | em_sti_write(p, STI_CONTROL, 1); | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
89 | static void em_sti_disable(struct em_sti_priv *p) | |
90 | { | |
91 | /* mask interrupts */ | |
92 | em_sti_write(p, STI_INTENCLR, 3); | |
93 | ||
94 | /* stop clock */ | |
3814ae09 | 95 | clk_disable(p->clk); |
b9dbf951 MD |
96 | } |
97 | ||
a5a1d1c2 | 98 | static u64 em_sti_count(struct em_sti_priv *p) |
b9dbf951 | 99 | { |
a5a1d1c2 | 100 | u64 ticks; |
b9dbf951 MD |
101 | unsigned long flags; |
102 | ||
103 | /* the STI hardware buffers the 48-bit count, but to | |
104 | * break it out into two 32-bit access the registers | |
105 | * must be accessed in a certain order. | |
106 | * Always read STI_COUNT_H before STI_COUNT_L. | |
107 | */ | |
108 | raw_spin_lock_irqsave(&p->lock, flags); | |
a5a1d1c2 | 109 | ticks = (u64)(em_sti_read(p, STI_COUNT_H) & 0xffff) << 32; |
b9dbf951 MD |
110 | ticks |= em_sti_read(p, STI_COUNT_L); |
111 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
112 | ||
113 | return ticks; | |
114 | } | |
115 | ||
a5a1d1c2 | 116 | static u64 em_sti_set_next(struct em_sti_priv *p, u64 next) |
b9dbf951 MD |
117 | { |
118 | unsigned long flags; | |
119 | ||
120 | raw_spin_lock_irqsave(&p->lock, flags); | |
121 | ||
122 | /* mask compare A interrupt */ | |
123 | em_sti_write(p, STI_INTENCLR, 1); | |
124 | ||
125 | /* update compare A value */ | |
126 | em_sti_write(p, STI_COMPA_H, next >> 32); | |
127 | em_sti_write(p, STI_COMPA_L, next & 0xffffffff); | |
128 | ||
129 | /* clear compare A interrupt source */ | |
130 | em_sti_write(p, STI_INTFFCLR, 1); | |
131 | ||
132 | /* unmask compare A interrupt */ | |
133 | em_sti_write(p, STI_INTENSET, 1); | |
134 | ||
135 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
136 | ||
137 | return next; | |
138 | } | |
139 | ||
140 | static irqreturn_t em_sti_interrupt(int irq, void *dev_id) | |
141 | { | |
142 | struct em_sti_priv *p = dev_id; | |
143 | ||
144 | p->ced.event_handler(&p->ced); | |
145 | return IRQ_HANDLED; | |
146 | } | |
147 | ||
148 | static int em_sti_start(struct em_sti_priv *p, unsigned int user) | |
149 | { | |
150 | unsigned long flags; | |
151 | int used_before; | |
152 | int ret = 0; | |
153 | ||
154 | raw_spin_lock_irqsave(&p->lock, flags); | |
155 | used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
156 | if (!used_before) | |
157 | ret = em_sti_enable(p); | |
158 | ||
159 | if (!ret) | |
160 | p->active[user] = 1; | |
161 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
162 | ||
163 | return ret; | |
164 | } | |
165 | ||
166 | static void em_sti_stop(struct em_sti_priv *p, unsigned int user) | |
167 | { | |
168 | unsigned long flags; | |
169 | int used_before, used_after; | |
170 | ||
171 | raw_spin_lock_irqsave(&p->lock, flags); | |
172 | used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
173 | p->active[user] = 0; | |
174 | used_after = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; | |
175 | ||
176 | if (used_before && !used_after) | |
177 | em_sti_disable(p); | |
178 | raw_spin_unlock_irqrestore(&p->lock, flags); | |
179 | } | |
180 | ||
181 | static struct em_sti_priv *cs_to_em_sti(struct clocksource *cs) | |
182 | { | |
183 | return container_of(cs, struct em_sti_priv, cs); | |
184 | } | |
185 | ||
a5a1d1c2 | 186 | static u64 em_sti_clocksource_read(struct clocksource *cs) |
b9dbf951 MD |
187 | { |
188 | return em_sti_count(cs_to_em_sti(cs)); | |
189 | } | |
190 | ||
191 | static int em_sti_clocksource_enable(struct clocksource *cs) | |
192 | { | |
b9dbf951 MD |
193 | struct em_sti_priv *p = cs_to_em_sti(cs); |
194 | ||
4e53aa2f | 195 | return em_sti_start(p, USER_CLOCKSOURCE); |
b9dbf951 MD |
196 | } |
197 | ||
198 | static void em_sti_clocksource_disable(struct clocksource *cs) | |
199 | { | |
200 | em_sti_stop(cs_to_em_sti(cs), USER_CLOCKSOURCE); | |
201 | } | |
202 | ||
203 | static void em_sti_clocksource_resume(struct clocksource *cs) | |
204 | { | |
205 | em_sti_clocksource_enable(cs); | |
206 | } | |
207 | ||
208 | static int em_sti_register_clocksource(struct em_sti_priv *p) | |
209 | { | |
210 | struct clocksource *cs = &p->cs; | |
211 | ||
b9dbf951 MD |
212 | cs->name = dev_name(&p->pdev->dev); |
213 | cs->rating = 200; | |
214 | cs->read = em_sti_clocksource_read; | |
215 | cs->enable = em_sti_clocksource_enable; | |
216 | cs->disable = em_sti_clocksource_disable; | |
217 | cs->suspend = em_sti_clocksource_disable; | |
218 | cs->resume = em_sti_clocksource_resume; | |
219 | cs->mask = CLOCKSOURCE_MASK(48); | |
220 | cs->flags = CLOCK_SOURCE_IS_CONTINUOUS; | |
221 | ||
222 | dev_info(&p->pdev->dev, "used as clock source\n"); | |
223 | ||
4e53aa2f | 224 | clocksource_register_hz(cs, p->rate); |
b9dbf951 MD |
225 | return 0; |
226 | } | |
227 | ||
228 | static struct em_sti_priv *ced_to_em_sti(struct clock_event_device *ced) | |
229 | { | |
230 | return container_of(ced, struct em_sti_priv, ced); | |
231 | } | |
232 | ||
75f94061 | 233 | static int em_sti_clock_event_shutdown(struct clock_event_device *ced) |
b9dbf951 MD |
234 | { |
235 | struct em_sti_priv *p = ced_to_em_sti(ced); | |
75f94061 VK |
236 | em_sti_stop(p, USER_CLOCKEVENT); |
237 | return 0; | |
238 | } | |
b9dbf951 | 239 | |
75f94061 VK |
240 | static int em_sti_clock_event_set_oneshot(struct clock_event_device *ced) |
241 | { | |
242 | struct em_sti_priv *p = ced_to_em_sti(ced); | |
b9dbf951 | 243 | |
75f94061 VK |
244 | dev_info(&p->pdev->dev, "used for oneshot clock events\n"); |
245 | em_sti_start(p, USER_CLOCKEVENT); | |
75f94061 | 246 | return 0; |
b9dbf951 MD |
247 | } |
248 | ||
249 | static int em_sti_clock_event_next(unsigned long delta, | |
250 | struct clock_event_device *ced) | |
251 | { | |
252 | struct em_sti_priv *p = ced_to_em_sti(ced); | |
a5a1d1c2 | 253 | u64 next; |
b9dbf951 MD |
254 | int safe; |
255 | ||
256 | next = em_sti_set_next(p, em_sti_count(p) + delta); | |
257 | safe = em_sti_count(p) < (next - 1); | |
258 | ||
259 | return !safe; | |
260 | } | |
261 | ||
262 | static void em_sti_register_clockevent(struct em_sti_priv *p) | |
263 | { | |
264 | struct clock_event_device *ced = &p->ced; | |
265 | ||
b9dbf951 MD |
266 | ced->name = dev_name(&p->pdev->dev); |
267 | ced->features = CLOCK_EVT_FEAT_ONESHOT; | |
268 | ced->rating = 200; | |
2199a557 | 269 | ced->cpumask = cpu_possible_mask; |
b9dbf951 | 270 | ced->set_next_event = em_sti_clock_event_next; |
75f94061 VK |
271 | ced->set_state_shutdown = em_sti_clock_event_shutdown; |
272 | ced->set_state_oneshot = em_sti_clock_event_set_oneshot; | |
b9dbf951 MD |
273 | |
274 | dev_info(&p->pdev->dev, "used for clock events\n"); | |
275 | ||
4e53aa2f | 276 | clockevents_config_and_register(ced, p->rate, 2, 0xffffffff); |
b9dbf951 MD |
277 | } |
278 | ||
1850514b | 279 | static int em_sti_probe(struct platform_device *pdev) |
b9dbf951 MD |
280 | { |
281 | struct em_sti_priv *p; | |
ba25322e | 282 | int irq, ret; |
b9dbf951 | 283 | |
1745e696 | 284 | p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL); |
39dd5677 | 285 | if (p == NULL) |
1745e696 | 286 | return -ENOMEM; |
b9dbf951 MD |
287 | |
288 | p->pdev = pdev; | |
289 | platform_set_drvdata(pdev, p); | |
290 | ||
b9dbf951 | 291 | irq = platform_get_irq(pdev, 0); |
9f475d08 | 292 | if (irq < 0) |
5c23a558 | 293 | return irq; |
b9dbf951 MD |
294 | |
295 | /* map memory, let base point to the STI instance */ | |
9a97b2fb | 296 | p->base = devm_platform_ioremap_resource(pdev, 0); |
1745e696 LP |
297 | if (IS_ERR(p->base)) |
298 | return PTR_ERR(p->base); | |
b9dbf951 | 299 | |
5c23a558 GS |
300 | ret = devm_request_irq(&pdev->dev, irq, em_sti_interrupt, |
301 | IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, | |
302 | dev_name(&pdev->dev), p); | |
303 | if (ret) { | |
3814ae09 | 304 | dev_err(&pdev->dev, "failed to request low IRQ\n"); |
5c23a558 | 305 | return ret; |
3814ae09 NS |
306 | } |
307 | ||
b9dbf951 | 308 | /* get hold of clock */ |
1745e696 | 309 | p->clk = devm_clk_get(&pdev->dev, "sclk"); |
b9dbf951 MD |
310 | if (IS_ERR(p->clk)) { |
311 | dev_err(&pdev->dev, "cannot get clock\n"); | |
1745e696 | 312 | return PTR_ERR(p->clk); |
b9dbf951 MD |
313 | } |
314 | ||
3814ae09 NS |
315 | ret = clk_prepare(p->clk); |
316 | if (ret < 0) { | |
317 | dev_err(&pdev->dev, "cannot prepare clock\n"); | |
318 | return ret; | |
b9dbf951 MD |
319 | } |
320 | ||
4e53aa2f NS |
321 | ret = clk_enable(p->clk); |
322 | if (ret < 0) { | |
323 | dev_err(&p->pdev->dev, "cannot enable clock\n"); | |
324 | clk_unprepare(p->clk); | |
325 | return ret; | |
326 | } | |
327 | p->rate = clk_get_rate(p->clk); | |
328 | clk_disable(p->clk); | |
329 | ||
b9dbf951 MD |
330 | raw_spin_lock_init(&p->lock); |
331 | em_sti_register_clockevent(p); | |
332 | em_sti_register_clocksource(p); | |
333 | return 0; | |
b9dbf951 MD |
334 | } |
335 | ||
1850514b | 336 | static int em_sti_remove(struct platform_device *pdev) |
b9dbf951 MD |
337 | { |
338 | return -EBUSY; /* cannot unregister clockevent and clocksource */ | |
339 | } | |
340 | ||
1850514b | 341 | static const struct of_device_id em_sti_dt_ids[] = { |
fc0830fe MD |
342 | { .compatible = "renesas,em-sti", }, |
343 | {}, | |
344 | }; | |
345 | MODULE_DEVICE_TABLE(of, em_sti_dt_ids); | |
346 | ||
b9dbf951 MD |
347 | static struct platform_driver em_sti_device_driver = { |
348 | .probe = em_sti_probe, | |
1850514b | 349 | .remove = em_sti_remove, |
b9dbf951 MD |
350 | .driver = { |
351 | .name = "em_sti", | |
fc0830fe | 352 | .of_match_table = em_sti_dt_ids, |
b9dbf951 MD |
353 | } |
354 | }; | |
355 | ||
09acc3a1 SH |
356 | static int __init em_sti_init(void) |
357 | { | |
358 | return platform_driver_register(&em_sti_device_driver); | |
359 | } | |
360 | ||
361 | static void __exit em_sti_exit(void) | |
362 | { | |
363 | platform_driver_unregister(&em_sti_device_driver); | |
364 | } | |
365 | ||
366 | subsys_initcall(em_sti_init); | |
367 | module_exit(em_sti_exit); | |
b9dbf951 MD |
368 | |
369 | MODULE_AUTHOR("Magnus Damm"); | |
370 | MODULE_DESCRIPTION("Renesas Emma Mobile STI Timer Driver"); | |
371 | MODULE_LICENSE("GPL v2"); |