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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
35enum { USER_CLOCKSOURCE, USER_CLOCKEVENT, USER_NR };
36
37struct 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
65static inline unsigned long em_sti_read(struct em_sti_priv *p, int offs)
66{
67 return ioread32(p->base + offs);
68}
69
70static 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
76static int em_sti_enable(struct em_sti_priv *p)
77{
78 int ret;
79
80
81 ret = clk_prepare_enable(p->clk);
82 if (ret) {
83 dev_err(&p->pdev->dev, "cannot enable clock\n");
84 return ret;
85 }
86
87
88 p->rate = clk_get_rate(p->clk);
89
90
91 em_sti_write(p, STI_SET_H, 0x40000000);
92 em_sti_write(p, STI_SET_L, 0x00000000);
93
94
95 em_sti_write(p, STI_INTENCLR, 3);
96 em_sti_write(p, STI_INTFFCLR, 3);
97
98
99 em_sti_write(p, STI_CONTROL, 1);
100
101 return 0;
102}
103
104static void em_sti_disable(struct em_sti_priv *p)
105{
106
107 em_sti_write(p, STI_INTENCLR, 3);
108
109
110 clk_disable_unprepare(p->clk);
111}
112
113static cycle_t em_sti_count(struct em_sti_priv *p)
114{
115 cycle_t ticks;
116 unsigned long flags;
117
118
119
120
121
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
131static 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
138 em_sti_write(p, STI_INTENCLR, 1);
139
140
141 em_sti_write(p, STI_COMPA_H, next >> 32);
142 em_sti_write(p, STI_COMPA_L, next & 0xffffffff);
143
144
145 em_sti_write(p, STI_INTFFCLR, 1);
146
147
148 em_sti_write(p, STI_INTENSET, 1);
149
150 raw_spin_unlock_irqrestore(&p->lock, flags);
151
152 return next;
153}
154
155static 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
163static 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
181static 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
196static struct em_sti_priv *cs_to_em_sti(struct clocksource *cs)
197{
198 return container_of(cs, struct em_sti_priv, cs);
199}
200
201static cycle_t em_sti_clocksource_read(struct clocksource *cs)
202{
203 return em_sti_count(cs_to_em_sti(cs));
204}
205
206static 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_update_freq_hz(cs, p->rate);
214 return ret;
215}
216
217static void em_sti_clocksource_disable(struct clocksource *cs)
218{
219 em_sti_stop(cs_to_em_sti(cs), USER_CLOCKSOURCE);
220}
221
222static void em_sti_clocksource_resume(struct clocksource *cs)
223{
224 em_sti_clocksource_enable(cs);
225}
226
227static int em_sti_register_clocksource(struct em_sti_priv *p)
228{
229 struct clocksource *cs = &p->cs;
230
231 cs->name = dev_name(&p->pdev->dev);
232 cs->rating = 200;
233 cs->read = em_sti_clocksource_read;
234 cs->enable = em_sti_clocksource_enable;
235 cs->disable = em_sti_clocksource_disable;
236 cs->suspend = em_sti_clocksource_disable;
237 cs->resume = em_sti_clocksource_resume;
238 cs->mask = CLOCKSOURCE_MASK(48);
239 cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
240
241 dev_info(&p->pdev->dev, "used as clock source\n");
242
243
244 clocksource_register_hz(cs, 1);
245 return 0;
246}
247
248static struct em_sti_priv *ced_to_em_sti(struct clock_event_device *ced)
249{
250 return container_of(ced, struct em_sti_priv, ced);
251}
252
253static int em_sti_clock_event_shutdown(struct clock_event_device *ced)
254{
255 struct em_sti_priv *p = ced_to_em_sti(ced);
256 em_sti_stop(p, USER_CLOCKEVENT);
257 return 0;
258}
259
260static int em_sti_clock_event_set_oneshot(struct clock_event_device *ced)
261{
262 struct em_sti_priv *p = ced_to_em_sti(ced);
263
264 dev_info(&p->pdev->dev, "used for oneshot clock events\n");
265 em_sti_start(p, USER_CLOCKEVENT);
266 clockevents_config(&p->ced, p->rate);
267 return 0;
268}
269
270static int em_sti_clock_event_next(unsigned long delta,
271 struct clock_event_device *ced)
272{
273 struct em_sti_priv *p = ced_to_em_sti(ced);
274 cycle_t next;
275 int safe;
276
277 next = em_sti_set_next(p, em_sti_count(p) + delta);
278 safe = em_sti_count(p) < (next - 1);
279
280 return !safe;
281}
282
283static void em_sti_register_clockevent(struct em_sti_priv *p)
284{
285 struct clock_event_device *ced = &p->ced;
286
287 ced->name = dev_name(&p->pdev->dev);
288 ced->features = CLOCK_EVT_FEAT_ONESHOT;
289 ced->rating = 200;
290 ced->cpumask = cpu_possible_mask;
291 ced->set_next_event = em_sti_clock_event_next;
292 ced->set_state_shutdown = em_sti_clock_event_shutdown;
293 ced->set_state_oneshot = em_sti_clock_event_set_oneshot;
294
295 dev_info(&p->pdev->dev, "used for clock events\n");
296
297
298 clockevents_config_and_register(ced, 1, 2, 0xffffffff);
299}
300
301static int em_sti_probe(struct platform_device *pdev)
302{
303 struct em_sti_priv *p;
304 struct resource *res;
305 int irq;
306
307 p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
308 if (p == NULL)
309 return -ENOMEM;
310
311 p->pdev = pdev;
312 platform_set_drvdata(pdev, p);
313
314 irq = platform_get_irq(pdev, 0);
315 if (irq < 0) {
316 dev_err(&pdev->dev, "failed to get irq\n");
317 return -EINVAL;
318 }
319
320
321 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
322 p->base = devm_ioremap_resource(&pdev->dev, res);
323 if (IS_ERR(p->base))
324 return PTR_ERR(p->base);
325
326
327 p->clk = devm_clk_get(&pdev->dev, "sclk");
328 if (IS_ERR(p->clk)) {
329 dev_err(&pdev->dev, "cannot get clock\n");
330 return PTR_ERR(p->clk);
331 }
332
333 if (devm_request_irq(&pdev->dev, irq, em_sti_interrupt,
334 IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
335 dev_name(&pdev->dev), p)) {
336 dev_err(&pdev->dev, "failed to request low IRQ\n");
337 return -ENOENT;
338 }
339
340 raw_spin_lock_init(&p->lock);
341 em_sti_register_clockevent(p);
342 em_sti_register_clocksource(p);
343 return 0;
344}
345
346static int em_sti_remove(struct platform_device *pdev)
347{
348 return -EBUSY;
349}
350
351static const struct of_device_id em_sti_dt_ids[] = {
352 { .compatible = "renesas,em-sti", },
353 {},
354};
355MODULE_DEVICE_TABLE(of, em_sti_dt_ids);
356
357static struct platform_driver em_sti_device_driver = {
358 .probe = em_sti_probe,
359 .remove = em_sti_remove,
360 .driver = {
361 .name = "em_sti",
362 .of_match_table = em_sti_dt_ids,
363 }
364};
365
366static int __init em_sti_init(void)
367{
368 return platform_driver_register(&em_sti_device_driver);
369}
370
371static void __exit em_sti_exit(void)
372{
373 platform_driver_unregister(&em_sti_device_driver);
374}
375
376subsys_initcall(em_sti_init);
377module_exit(em_sti_exit);
378
379MODULE_AUTHOR("Magnus Damm");
380MODULE_DESCRIPTION("Renesas Emma Mobile STI Timer Driver");
381MODULE_LICENSE("GPL v2");
382
