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1/*
2 * SuperH Timer Support - CMT
3 *
4 * Copyright (C) 2008 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/sh_timer.h>
33#include <linux/slab.h>
34#include <linux/module.h>
35#include <linux/pm_domain.h>
36
37struct sh_cmt_priv {
38 void __iomem *mapbase;
39 struct clk *clk;
40 unsigned long width; /* 16 or 32 bit version of hardware block */
41 unsigned long overflow_bit;
42 unsigned long clear_bits;
43 struct irqaction irqaction;
44 struct platform_device *pdev;
45
46 unsigned long flags;
47 unsigned long match_value;
48 unsigned long next_match_value;
49 unsigned long max_match_value;
50 unsigned long rate;
51 raw_spinlock_t lock;
52 struct clock_event_device ced;
53 struct clocksource cs;
54 unsigned long total_cycles;
55};
56
57static DEFINE_RAW_SPINLOCK(sh_cmt_lock);
58
59#define CMSTR -1 /* shared register */
60#define CMCSR 0 /* channel register */
61#define CMCNT 1 /* channel register */
62#define CMCOR 2 /* channel register */
63
64static inline unsigned long sh_cmt_read(struct sh_cmt_priv *p, int reg_nr)
65{
66 struct sh_timer_config *cfg = p->pdev->dev.platform_data;
67 void __iomem *base = p->mapbase;
68 unsigned long offs;
69
70 if (reg_nr == CMSTR) {
71 offs = 0;
72 base -= cfg->channel_offset;
73 } else
74 offs = reg_nr;
75
76 if (p->width == 16)
77 offs <<= 1;
78 else {
79 offs <<= 2;
80 if ((reg_nr == CMCNT) || (reg_nr == CMCOR))
81 return ioread32(base + offs);
82 }
83
84 return ioread16(base + offs);
85}
86
87static inline void sh_cmt_write(struct sh_cmt_priv *p, int reg_nr,
88 unsigned long value)
89{
90 struct sh_timer_config *cfg = p->pdev->dev.platform_data;
91 void __iomem *base = p->mapbase;
92 unsigned long offs;
93
94 if (reg_nr == CMSTR) {
95 offs = 0;
96 base -= cfg->channel_offset;
97 } else
98 offs = reg_nr;
99
100 if (p->width == 16)
101 offs <<= 1;
102 else {
103 offs <<= 2;
104 if ((reg_nr == CMCNT) || (reg_nr == CMCOR)) {
105 iowrite32(value, base + offs);
106 return;
107 }
108 }
109
110 iowrite16(value, base + offs);
111}
112
113static unsigned long sh_cmt_get_counter(struct sh_cmt_priv *p,
114 int *has_wrapped)
115{
116 unsigned long v1, v2, v3;
117 int o1, o2;
118
119 o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
120
121 /* Make sure the timer value is stable. Stolen from acpi_pm.c */
122 do {
123 o2 = o1;
124 v1 = sh_cmt_read(p, CMCNT);
125 v2 = sh_cmt_read(p, CMCNT);
126 v3 = sh_cmt_read(p, CMCNT);
127 o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
128 } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
129 || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
130
131 *has_wrapped = o1;
132 return v2;
133}
134
135
136static void sh_cmt_start_stop_ch(struct sh_cmt_priv *p, int start)
137{
138 struct sh_timer_config *cfg = p->pdev->dev.platform_data;
139 unsigned long flags, value;
140
141 /* start stop register shared by multiple timer channels */
142 raw_spin_lock_irqsave(&sh_cmt_lock, flags);
143 value = sh_cmt_read(p, CMSTR);
144
145 if (start)
146 value |= 1 << cfg->timer_bit;
147 else
148 value &= ~(1 << cfg->timer_bit);
149
150 sh_cmt_write(p, CMSTR, value);
151 raw_spin_unlock_irqrestore(&sh_cmt_lock, flags);
152}
153
154static int sh_cmt_enable(struct sh_cmt_priv *p, unsigned long *rate)
155{
156 int k, ret;
157
158 /* enable clock */
159 ret = clk_enable(p->clk);
160 if (ret) {
161 dev_err(&p->pdev->dev, "cannot enable clock\n");
162 goto err0;
163 }
164
165 /* make sure channel is disabled */
166 sh_cmt_start_stop_ch(p, 0);
167
168 /* configure channel, periodic mode and maximum timeout */
169 if (p->width == 16) {
170 *rate = clk_get_rate(p->clk) / 512;
171 sh_cmt_write(p, CMCSR, 0x43);
172 } else {
173 *rate = clk_get_rate(p->clk) / 8;
174 sh_cmt_write(p, CMCSR, 0x01a4);
175 }
176
177 sh_cmt_write(p, CMCOR, 0xffffffff);
178 sh_cmt_write(p, CMCNT, 0);
179
180 /*
181 * According to the sh73a0 user's manual, as CMCNT can be operated
182 * only by the RCLK (Pseudo 32 KHz), there's one restriction on
183 * modifying CMCNT register; two RCLK cycles are necessary before
184 * this register is either read or any modification of the value
185 * it holds is reflected in the LSI's actual operation.
186 *
187 * While at it, we're supposed to clear out the CMCNT as of this
188 * moment, so make sure it's processed properly here. This will
189 * take RCLKx2 at maximum.
190 */
191 for (k = 0; k < 100; k++) {
192 if (!sh_cmt_read(p, CMCNT))
193 break;
194 udelay(1);
195 }
196
197 if (sh_cmt_read(p, CMCNT)) {
198 dev_err(&p->pdev->dev, "cannot clear CMCNT\n");
199 ret = -ETIMEDOUT;
200 goto err1;
201 }
202
203 /* enable channel */
204 sh_cmt_start_stop_ch(p, 1);
205 return 0;
206 err1:
207 /* stop clock */
208 clk_disable(p->clk);
209
210 err0:
211 return ret;
212}
213
214static void sh_cmt_disable(struct sh_cmt_priv *p)
215{
216 /* disable channel */
217 sh_cmt_start_stop_ch(p, 0);
218
219 /* disable interrupts in CMT block */
220 sh_cmt_write(p, CMCSR, 0);
221
222 /* stop clock */
223 clk_disable(p->clk);
224}
225
226/* private flags */
227#define FLAG_CLOCKEVENT (1 << 0)
228#define FLAG_CLOCKSOURCE (1 << 1)
229#define FLAG_REPROGRAM (1 << 2)
230#define FLAG_SKIPEVENT (1 << 3)
231#define FLAG_IRQCONTEXT (1 << 4)
232
233static void sh_cmt_clock_event_program_verify(struct sh_cmt_priv *p,
234 int absolute)
235{
236 unsigned long new_match;
237 unsigned long value = p->next_match_value;
238 unsigned long delay = 0;
239 unsigned long now = 0;
240 int has_wrapped;
241
242 now = sh_cmt_get_counter(p, &has_wrapped);
243 p->flags |= FLAG_REPROGRAM; /* force reprogram */
244
245 if (has_wrapped) {
246 /* we're competing with the interrupt handler.
247 * -> let the interrupt handler reprogram the timer.
248 * -> interrupt number two handles the event.
249 */
250 p->flags |= FLAG_SKIPEVENT;
251 return;
252 }
253
254 if (absolute)
255 now = 0;
256
257 do {
258 /* reprogram the timer hardware,
259 * but don't save the new match value yet.
260 */
261 new_match = now + value + delay;
262 if (new_match > p->max_match_value)
263 new_match = p->max_match_value;
264
265 sh_cmt_write(p, CMCOR, new_match);
266
267 now = sh_cmt_get_counter(p, &has_wrapped);
268 if (has_wrapped && (new_match > p->match_value)) {
269 /* we are changing to a greater match value,
270 * so this wrap must be caused by the counter
271 * matching the old value.
272 * -> first interrupt reprograms the timer.
273 * -> interrupt number two handles the event.
274 */
275 p->flags |= FLAG_SKIPEVENT;
276 break;
277 }
278
279 if (has_wrapped) {
280 /* we are changing to a smaller match value,
281 * so the wrap must be caused by the counter
282 * matching the new value.
283 * -> save programmed match value.
284 * -> let isr handle the event.
285 */
286 p->match_value = new_match;
287 break;
288 }
289
290 /* be safe: verify hardware settings */
291 if (now < new_match) {
292 /* timer value is below match value, all good.
293 * this makes sure we won't miss any match events.
294 * -> save programmed match value.
295 * -> let isr handle the event.
296 */
297 p->match_value = new_match;
298 break;
299 }
300
301 /* the counter has reached a value greater
302 * than our new match value. and since the
303 * has_wrapped flag isn't set we must have
304 * programmed a too close event.
305 * -> increase delay and retry.
306 */
307 if (delay)
308 delay <<= 1;
309 else
310 delay = 1;
311
312 if (!delay)
313 dev_warn(&p->pdev->dev, "too long delay\n");
314
315 } while (delay);
316}
317
318static void __sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)
319{
320 if (delta > p->max_match_value)
321 dev_warn(&p->pdev->dev, "delta out of range\n");
322
323 p->next_match_value = delta;
324 sh_cmt_clock_event_program_verify(p, 0);
325}
326
327static void sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)
328{
329 unsigned long flags;
330
331 raw_spin_lock_irqsave(&p->lock, flags);
332 __sh_cmt_set_next(p, delta);
333 raw_spin_unlock_irqrestore(&p->lock, flags);
334}
335
336static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
337{
338 struct sh_cmt_priv *p = dev_id;
339
340 /* clear flags */
341 sh_cmt_write(p, CMCSR, sh_cmt_read(p, CMCSR) & p->clear_bits);
342
343 /* update clock source counter to begin with if enabled
344 * the wrap flag should be cleared by the timer specific
345 * isr before we end up here.
346 */
347 if (p->flags & FLAG_CLOCKSOURCE)
348 p->total_cycles += p->match_value + 1;
349
350 if (!(p->flags & FLAG_REPROGRAM))
351 p->next_match_value = p->max_match_value;
352
353 p->flags |= FLAG_IRQCONTEXT;
354
355 if (p->flags & FLAG_CLOCKEVENT) {
356 if (!(p->flags & FLAG_SKIPEVENT)) {
357 if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT) {
358 p->next_match_value = p->max_match_value;
359 p->flags |= FLAG_REPROGRAM;
360 }
361
362 p->ced.event_handler(&p->ced);
363 }
364 }
365
366 p->flags &= ~FLAG_SKIPEVENT;
367
368 if (p->flags & FLAG_REPROGRAM) {
369 p->flags &= ~FLAG_REPROGRAM;
370 sh_cmt_clock_event_program_verify(p, 1);
371
372 if (p->flags & FLAG_CLOCKEVENT)
373 if ((p->ced.mode == CLOCK_EVT_MODE_SHUTDOWN)
374 || (p->match_value == p->next_match_value))
375 p->flags &= ~FLAG_REPROGRAM;
376 }
377
378 p->flags &= ~FLAG_IRQCONTEXT;
379
380 return IRQ_HANDLED;
381}
382
383static int sh_cmt_start(struct sh_cmt_priv *p, unsigned long flag)
384{
385 int ret = 0;
386 unsigned long flags;
387
388 raw_spin_lock_irqsave(&p->lock, flags);
389
390 if (!(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
391 ret = sh_cmt_enable(p, &p->rate);
392
393 if (ret)
394 goto out;
395 p->flags |= flag;
396
397 /* setup timeout if no clockevent */
398 if ((flag == FLAG_CLOCKSOURCE) && (!(p->flags & FLAG_CLOCKEVENT)))
399 __sh_cmt_set_next(p, p->max_match_value);
400 out:
401 raw_spin_unlock_irqrestore(&p->lock, flags);
402
403 return ret;
404}
405
406static void sh_cmt_stop(struct sh_cmt_priv *p, unsigned long flag)
407{
408 unsigned long flags;
409 unsigned long f;
410
411 raw_spin_lock_irqsave(&p->lock, flags);
412
413 f = p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
414 p->flags &= ~flag;
415
416 if (f && !(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
417 sh_cmt_disable(p);
418
419 /* adjust the timeout to maximum if only clocksource left */
420 if ((flag == FLAG_CLOCKEVENT) && (p->flags & FLAG_CLOCKSOURCE))
421 __sh_cmt_set_next(p, p->max_match_value);
422
423 raw_spin_unlock_irqrestore(&p->lock, flags);
424}
425
426static struct sh_cmt_priv *cs_to_sh_cmt(struct clocksource *cs)
427{
428 return container_of(cs, struct sh_cmt_priv, cs);
429}
430
431static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
432{
433 struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
434 unsigned long flags, raw;
435 unsigned long value;
436 int has_wrapped;
437
438 raw_spin_lock_irqsave(&p->lock, flags);
439 value = p->total_cycles;
440 raw = sh_cmt_get_counter(p, &has_wrapped);
441
442 if (unlikely(has_wrapped))
443 raw += p->match_value + 1;
444 raw_spin_unlock_irqrestore(&p->lock, flags);
445
446 return value + raw;
447}
448
449static int sh_cmt_clocksource_enable(struct clocksource *cs)
450{
451 int ret;
452 struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
453
454 p->total_cycles = 0;
455
456 ret = sh_cmt_start(p, FLAG_CLOCKSOURCE);
457 if (!ret)
458 __clocksource_updatefreq_hz(cs, p->rate);
459 return ret;
460}
461
462static void sh_cmt_clocksource_disable(struct clocksource *cs)
463{
464 sh_cmt_stop(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
465}
466
467static void sh_cmt_clocksource_resume(struct clocksource *cs)
468{
469 sh_cmt_start(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
470}
471
472static int sh_cmt_register_clocksource(struct sh_cmt_priv *p,
473 char *name, unsigned long rating)
474{
475 struct clocksource *cs = &p->cs;
476
477 cs->name = name;
478 cs->rating = rating;
479 cs->read = sh_cmt_clocksource_read;
480 cs->enable = sh_cmt_clocksource_enable;
481 cs->disable = sh_cmt_clocksource_disable;
482 cs->suspend = sh_cmt_clocksource_disable;
483 cs->resume = sh_cmt_clocksource_resume;
484 cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
485 cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
486
487 dev_info(&p->pdev->dev, "used as clock source\n");
488
489 /* Register with dummy 1 Hz value, gets updated in ->enable() */
490 clocksource_register_hz(cs, 1);
491 return 0;
492}
493
494static struct sh_cmt_priv *ced_to_sh_cmt(struct clock_event_device *ced)
495{
496 return container_of(ced, struct sh_cmt_priv, ced);
497}
498
499static void sh_cmt_clock_event_start(struct sh_cmt_priv *p, int periodic)
500{
501 struct clock_event_device *ced = &p->ced;
502
503 sh_cmt_start(p, FLAG_CLOCKEVENT);
504
505 /* TODO: calculate good shift from rate and counter bit width */
506
507 ced->shift = 32;
508 ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
509 ced->max_delta_ns = clockevent_delta2ns(p->max_match_value, ced);
510 ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
511
512 if (periodic)
513 sh_cmt_set_next(p, ((p->rate + HZ/2) / HZ) - 1);
514 else
515 sh_cmt_set_next(p, p->max_match_value);
516}
517
518static void sh_cmt_clock_event_mode(enum clock_event_mode mode,
519 struct clock_event_device *ced)
520{
521 struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
522
523 /* deal with old setting first */
524 switch (ced->mode) {
525 case CLOCK_EVT_MODE_PERIODIC:
526 case CLOCK_EVT_MODE_ONESHOT:
527 sh_cmt_stop(p, FLAG_CLOCKEVENT);
528 break;
529 default:
530 break;
531 }
532
533 switch (mode) {
534 case CLOCK_EVT_MODE_PERIODIC:
535 dev_info(&p->pdev->dev, "used for periodic clock events\n");
536 sh_cmt_clock_event_start(p, 1);
537 break;
538 case CLOCK_EVT_MODE_ONESHOT:
539 dev_info(&p->pdev->dev, "used for oneshot clock events\n");
540 sh_cmt_clock_event_start(p, 0);
541 break;
542 case CLOCK_EVT_MODE_SHUTDOWN:
543 case CLOCK_EVT_MODE_UNUSED:
544 sh_cmt_stop(p, FLAG_CLOCKEVENT);
545 break;
546 default:
547 break;
548 }
549}
550
551static int sh_cmt_clock_event_next(unsigned long delta,
552 struct clock_event_device *ced)
553{
554 struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
555
556 BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
557 if (likely(p->flags & FLAG_IRQCONTEXT))
558 p->next_match_value = delta - 1;
559 else
560 sh_cmt_set_next(p, delta - 1);
561
562 return 0;
563}
564
565static void sh_cmt_register_clockevent(struct sh_cmt_priv *p,
566 char *name, unsigned long rating)
567{
568 struct clock_event_device *ced = &p->ced;
569
570 memset(ced, 0, sizeof(*ced));
571
572 ced->name = name;
573 ced->features = CLOCK_EVT_FEAT_PERIODIC;
574 ced->features |= CLOCK_EVT_FEAT_ONESHOT;
575 ced->rating = rating;
576 ced->cpumask = cpumask_of(0);
577 ced->set_next_event = sh_cmt_clock_event_next;
578 ced->set_mode = sh_cmt_clock_event_mode;
579
580 dev_info(&p->pdev->dev, "used for clock events\n");
581 clockevents_register_device(ced);
582}
583
584static int sh_cmt_register(struct sh_cmt_priv *p, char *name,
585 unsigned long clockevent_rating,
586 unsigned long clocksource_rating)
587{
588 if (p->width == (sizeof(p->max_match_value) * 8))
589 p->max_match_value = ~0;
590 else
591 p->max_match_value = (1 << p->width) - 1;
592
593 p->match_value = p->max_match_value;
594 raw_spin_lock_init(&p->lock);
595
596 if (clockevent_rating)
597 sh_cmt_register_clockevent(p, name, clockevent_rating);
598
599 if (clocksource_rating)
600 sh_cmt_register_clocksource(p, name, clocksource_rating);
601
602 return 0;
603}
604
605static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
606{
607 struct sh_timer_config *cfg = pdev->dev.platform_data;
608 struct resource *res;
609 int irq, ret;
610 ret = -ENXIO;
611
612 memset(p, 0, sizeof(*p));
613 p->pdev = pdev;
614
615 if (!cfg) {
616 dev_err(&p->pdev->dev, "missing platform data\n");
617 goto err0;
618 }
619
620 platform_set_drvdata(pdev, p);
621
622 res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
623 if (!res) {
624 dev_err(&p->pdev->dev, "failed to get I/O memory\n");
625 goto err0;
626 }
627
628 irq = platform_get_irq(p->pdev, 0);
629 if (irq < 0) {
630 dev_err(&p->pdev->dev, "failed to get irq\n");
631 goto err0;
632 }
633
634 /* map memory, let mapbase point to our channel */
635 p->mapbase = ioremap_nocache(res->start, resource_size(res));
636 if (p->mapbase == NULL) {
637 dev_err(&p->pdev->dev, "failed to remap I/O memory\n");
638 goto err0;
639 }
640
641 /* request irq using setup_irq() (too early for request_irq()) */
642 p->irqaction.name = dev_name(&p->pdev->dev);
643 p->irqaction.handler = sh_cmt_interrupt;
644 p->irqaction.dev_id = p;
645 p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | \
646 IRQF_IRQPOLL | IRQF_NOBALANCING;
647
648 /* get hold of clock */
649 p->clk = clk_get(&p->pdev->dev, "cmt_fck");
650 if (IS_ERR(p->clk)) {
651 dev_err(&p->pdev->dev, "cannot get clock\n");
652 ret = PTR_ERR(p->clk);
653 goto err1;
654 }
655
656 if (resource_size(res) == 6) {
657 p->width = 16;
658 p->overflow_bit = 0x80;
659 p->clear_bits = ~0x80;
660 } else {
661 p->width = 32;
662 p->overflow_bit = 0x8000;
663 p->clear_bits = ~0xc000;
664 }
665
666 ret = sh_cmt_register(p, (char *)dev_name(&p->pdev->dev),
667 cfg->clockevent_rating,
668 cfg->clocksource_rating);
669 if (ret) {
670 dev_err(&p->pdev->dev, "registration failed\n");
671 goto err1;
672 }
673
674 ret = setup_irq(irq, &p->irqaction);
675 if (ret) {
676 dev_err(&p->pdev->dev, "failed to request irq %d\n", irq);
677 goto err1;
678 }
679
680 return 0;
681
682err1:
683 iounmap(p->mapbase);
684err0:
685 return ret;
686}
687
688static int __devinit sh_cmt_probe(struct platform_device *pdev)
689{
690 struct sh_cmt_priv *p = platform_get_drvdata(pdev);
691 int ret;
692
693 if (!is_early_platform_device(pdev))
694 pm_genpd_dev_always_on(&pdev->dev, true);
695
696 if (p) {
697 dev_info(&pdev->dev, "kept as earlytimer\n");
698 return 0;
699 }
700
701 p = kmalloc(sizeof(*p), GFP_KERNEL);
702 if (p == NULL) {
703 dev_err(&pdev->dev, "failed to allocate driver data\n");
704 return -ENOMEM;
705 }
706
707 ret = sh_cmt_setup(p, pdev);
708 if (ret) {
709 kfree(p);
710 platform_set_drvdata(pdev, NULL);
711 }
712 return ret;
713}
714
715static int __devexit sh_cmt_remove(struct platform_device *pdev)
716{
717 return -EBUSY; /* cannot unregister clockevent and clocksource */
718}
719
720static struct platform_driver sh_cmt_device_driver = {
721 .probe = sh_cmt_probe,
722 .remove = __devexit_p(sh_cmt_remove),
723 .driver = {
724 .name = "sh_cmt",
725 }
726};
727
728static int __init sh_cmt_init(void)
729{
730 return platform_driver_register(&sh_cmt_device_driver);
731}
732
733static void __exit sh_cmt_exit(void)
734{
735 platform_driver_unregister(&sh_cmt_device_driver);
736}
737
738early_platform_init("earlytimer", &sh_cmt_device_driver);
739module_init(sh_cmt_init);
740module_exit(sh_cmt_exit);
741
742MODULE_AUTHOR("Magnus Damm");
743MODULE_DESCRIPTION("SuperH CMT Timer Driver");
744MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SuperH Timer Support - CMT
4 *
5 * Copyright (C) 2008 Magnus Damm
6 */
7
8#include <linux/clk.h>
9#include <linux/clockchips.h>
10#include <linux/clocksource.h>
11#include <linux/delay.h>
12#include <linux/err.h>
13#include <linux/init.h>
14#include <linux/interrupt.h>
15#include <linux/io.h>
16#include <linux/ioport.h>
17#include <linux/irq.h>
18#include <linux/module.h>
19#include <linux/of.h>
20#include <linux/of_device.h>
21#include <linux/platform_device.h>
22#include <linux/pm_domain.h>
23#include <linux/pm_runtime.h>
24#include <linux/sh_timer.h>
25#include <linux/slab.h>
26#include <linux/spinlock.h>
27
28struct sh_cmt_device;
29
30/*
31 * The CMT comes in 5 different identified flavours, depending not only on the
32 * SoC but also on the particular instance. The following table lists the main
33 * characteristics of those flavours.
34 *
35 * 16B 32B 32B-F 48B R-Car Gen2
36 * -----------------------------------------------------------------------------
37 * Channels 2 1/4 1 6 2/8
38 * Control Width 16 16 16 16 32
39 * Counter Width 16 32 32 32/48 32/48
40 * Shared Start/Stop Y Y Y Y N
41 *
42 * The r8a73a4 / R-Car Gen2 version has a per-channel start/stop register
43 * located in the channel registers block. All other versions have a shared
44 * start/stop register located in the global space.
45 *
46 * Channels are indexed from 0 to N-1 in the documentation. The channel index
47 * infers the start/stop bit position in the control register and the channel
48 * registers block address. Some CMT instances have a subset of channels
49 * available, in which case the index in the documentation doesn't match the
50 * "real" index as implemented in hardware. This is for instance the case with
51 * CMT0 on r8a7740, which is a 32-bit variant with a single channel numbered 0
52 * in the documentation but using start/stop bit 5 and having its registers
53 * block at 0x60.
54 *
55 * Similarly CMT0 on r8a73a4, r8a7790 and r8a7791, while implementing 32-bit
56 * channels only, is a 48-bit gen2 CMT with the 48-bit channels unavailable.
57 */
58
59enum sh_cmt_model {
60 SH_CMT_16BIT,
61 SH_CMT_32BIT,
62 SH_CMT_48BIT,
63 SH_CMT0_RCAR_GEN2,
64 SH_CMT1_RCAR_GEN2,
65};
66
67struct sh_cmt_info {
68 enum sh_cmt_model model;
69
70 unsigned int channels_mask;
71
72 unsigned long width; /* 16 or 32 bit version of hardware block */
73 u32 overflow_bit;
74 u32 clear_bits;
75
76 /* callbacks for CMSTR and CMCSR access */
77 u32 (*read_control)(void __iomem *base, unsigned long offs);
78 void (*write_control)(void __iomem *base, unsigned long offs,
79 u32 value);
80
81 /* callbacks for CMCNT and CMCOR access */
82 u32 (*read_count)(void __iomem *base, unsigned long offs);
83 void (*write_count)(void __iomem *base, unsigned long offs, u32 value);
84};
85
86struct sh_cmt_channel {
87 struct sh_cmt_device *cmt;
88
89 unsigned int index; /* Index in the documentation */
90 unsigned int hwidx; /* Real hardware index */
91
92 void __iomem *iostart;
93 void __iomem *ioctrl;
94
95 unsigned int timer_bit;
96 unsigned long flags;
97 u32 match_value;
98 u32 next_match_value;
99 u32 max_match_value;
100 raw_spinlock_t lock;
101 struct clock_event_device ced;
102 struct clocksource cs;
103 u64 total_cycles;
104 bool cs_enabled;
105};
106
107struct sh_cmt_device {
108 struct platform_device *pdev;
109
110 const struct sh_cmt_info *info;
111
112 void __iomem *mapbase;
113 struct clk *clk;
114 unsigned long rate;
115
116 raw_spinlock_t lock; /* Protect the shared start/stop register */
117
118 struct sh_cmt_channel *channels;
119 unsigned int num_channels;
120 unsigned int hw_channels;
121
122 bool has_clockevent;
123 bool has_clocksource;
124};
125
126#define SH_CMT16_CMCSR_CMF (1 << 7)
127#define SH_CMT16_CMCSR_CMIE (1 << 6)
128#define SH_CMT16_CMCSR_CKS8 (0 << 0)
129#define SH_CMT16_CMCSR_CKS32 (1 << 0)
130#define SH_CMT16_CMCSR_CKS128 (2 << 0)
131#define SH_CMT16_CMCSR_CKS512 (3 << 0)
132#define SH_CMT16_CMCSR_CKS_MASK (3 << 0)
133
134#define SH_CMT32_CMCSR_CMF (1 << 15)
135#define SH_CMT32_CMCSR_OVF (1 << 14)
136#define SH_CMT32_CMCSR_WRFLG (1 << 13)
137#define SH_CMT32_CMCSR_STTF (1 << 12)
138#define SH_CMT32_CMCSR_STPF (1 << 11)
139#define SH_CMT32_CMCSR_SSIE (1 << 10)
140#define SH_CMT32_CMCSR_CMS (1 << 9)
141#define SH_CMT32_CMCSR_CMM (1 << 8)
142#define SH_CMT32_CMCSR_CMTOUT_IE (1 << 7)
143#define SH_CMT32_CMCSR_CMR_NONE (0 << 4)
144#define SH_CMT32_CMCSR_CMR_DMA (1 << 4)
145#define SH_CMT32_CMCSR_CMR_IRQ (2 << 4)
146#define SH_CMT32_CMCSR_CMR_MASK (3 << 4)
147#define SH_CMT32_CMCSR_DBGIVD (1 << 3)
148#define SH_CMT32_CMCSR_CKS_RCLK8 (4 << 0)
149#define SH_CMT32_CMCSR_CKS_RCLK32 (5 << 0)
150#define SH_CMT32_CMCSR_CKS_RCLK128 (6 << 0)
151#define SH_CMT32_CMCSR_CKS_RCLK1 (7 << 0)
152#define SH_CMT32_CMCSR_CKS_MASK (7 << 0)
153
154static u32 sh_cmt_read16(void __iomem *base, unsigned long offs)
155{
156 return ioread16(base + (offs << 1));
157}
158
159static u32 sh_cmt_read32(void __iomem *base, unsigned long offs)
160{
161 return ioread32(base + (offs << 2));
162}
163
164static void sh_cmt_write16(void __iomem *base, unsigned long offs, u32 value)
165{
166 iowrite16(value, base + (offs << 1));
167}
168
169static void sh_cmt_write32(void __iomem *base, unsigned long offs, u32 value)
170{
171 iowrite32(value, base + (offs << 2));
172}
173
174static const struct sh_cmt_info sh_cmt_info[] = {
175 [SH_CMT_16BIT] = {
176 .model = SH_CMT_16BIT,
177 .width = 16,
178 .overflow_bit = SH_CMT16_CMCSR_CMF,
179 .clear_bits = ~SH_CMT16_CMCSR_CMF,
180 .read_control = sh_cmt_read16,
181 .write_control = sh_cmt_write16,
182 .read_count = sh_cmt_read16,
183 .write_count = sh_cmt_write16,
184 },
185 [SH_CMT_32BIT] = {
186 .model = SH_CMT_32BIT,
187 .width = 32,
188 .overflow_bit = SH_CMT32_CMCSR_CMF,
189 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
190 .read_control = sh_cmt_read16,
191 .write_control = sh_cmt_write16,
192 .read_count = sh_cmt_read32,
193 .write_count = sh_cmt_write32,
194 },
195 [SH_CMT_48BIT] = {
196 .model = SH_CMT_48BIT,
197 .channels_mask = 0x3f,
198 .width = 32,
199 .overflow_bit = SH_CMT32_CMCSR_CMF,
200 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
201 .read_control = sh_cmt_read32,
202 .write_control = sh_cmt_write32,
203 .read_count = sh_cmt_read32,
204 .write_count = sh_cmt_write32,
205 },
206 [SH_CMT0_RCAR_GEN2] = {
207 .model = SH_CMT0_RCAR_GEN2,
208 .channels_mask = 0x60,
209 .width = 32,
210 .overflow_bit = SH_CMT32_CMCSR_CMF,
211 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
212 .read_control = sh_cmt_read32,
213 .write_control = sh_cmt_write32,
214 .read_count = sh_cmt_read32,
215 .write_count = sh_cmt_write32,
216 },
217 [SH_CMT1_RCAR_GEN2] = {
218 .model = SH_CMT1_RCAR_GEN2,
219 .channels_mask = 0xff,
220 .width = 32,
221 .overflow_bit = SH_CMT32_CMCSR_CMF,
222 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
223 .read_control = sh_cmt_read32,
224 .write_control = sh_cmt_write32,
225 .read_count = sh_cmt_read32,
226 .write_count = sh_cmt_write32,
227 },
228};
229
230#define CMCSR 0 /* channel register */
231#define CMCNT 1 /* channel register */
232#define CMCOR 2 /* channel register */
233
234static inline u32 sh_cmt_read_cmstr(struct sh_cmt_channel *ch)
235{
236 if (ch->iostart)
237 return ch->cmt->info->read_control(ch->iostart, 0);
238 else
239 return ch->cmt->info->read_control(ch->cmt->mapbase, 0);
240}
241
242static inline void sh_cmt_write_cmstr(struct sh_cmt_channel *ch, u32 value)
243{
244 if (ch->iostart)
245 ch->cmt->info->write_control(ch->iostart, 0, value);
246 else
247 ch->cmt->info->write_control(ch->cmt->mapbase, 0, value);
248}
249
250static inline u32 sh_cmt_read_cmcsr(struct sh_cmt_channel *ch)
251{
252 return ch->cmt->info->read_control(ch->ioctrl, CMCSR);
253}
254
255static inline void sh_cmt_write_cmcsr(struct sh_cmt_channel *ch, u32 value)
256{
257 ch->cmt->info->write_control(ch->ioctrl, CMCSR, value);
258}
259
260static inline u32 sh_cmt_read_cmcnt(struct sh_cmt_channel *ch)
261{
262 return ch->cmt->info->read_count(ch->ioctrl, CMCNT);
263}
264
265static inline void sh_cmt_write_cmcnt(struct sh_cmt_channel *ch, u32 value)
266{
267 ch->cmt->info->write_count(ch->ioctrl, CMCNT, value);
268}
269
270static inline void sh_cmt_write_cmcor(struct sh_cmt_channel *ch, u32 value)
271{
272 ch->cmt->info->write_count(ch->ioctrl, CMCOR, value);
273}
274
275static u32 sh_cmt_get_counter(struct sh_cmt_channel *ch, u32 *has_wrapped)
276{
277 u32 v1, v2, v3;
278 u32 o1, o2;
279
280 o1 = sh_cmt_read_cmcsr(ch) & ch->cmt->info->overflow_bit;
281
282 /* Make sure the timer value is stable. Stolen from acpi_pm.c */
283 do {
284 o2 = o1;
285 v1 = sh_cmt_read_cmcnt(ch);
286 v2 = sh_cmt_read_cmcnt(ch);
287 v3 = sh_cmt_read_cmcnt(ch);
288 o1 = sh_cmt_read_cmcsr(ch) & ch->cmt->info->overflow_bit;
289 } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
290 || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
291
292 *has_wrapped = o1;
293 return v2;
294}
295
296static void sh_cmt_start_stop_ch(struct sh_cmt_channel *ch, int start)
297{
298 unsigned long flags;
299 u32 value;
300
301 /* start stop register shared by multiple timer channels */
302 raw_spin_lock_irqsave(&ch->cmt->lock, flags);
303 value = sh_cmt_read_cmstr(ch);
304
305 if (start)
306 value |= 1 << ch->timer_bit;
307 else
308 value &= ~(1 << ch->timer_bit);
309
310 sh_cmt_write_cmstr(ch, value);
311 raw_spin_unlock_irqrestore(&ch->cmt->lock, flags);
312}
313
314static int sh_cmt_enable(struct sh_cmt_channel *ch)
315{
316 int k, ret;
317
318 pm_runtime_get_sync(&ch->cmt->pdev->dev);
319 dev_pm_syscore_device(&ch->cmt->pdev->dev, true);
320
321 /* enable clock */
322 ret = clk_enable(ch->cmt->clk);
323 if (ret) {
324 dev_err(&ch->cmt->pdev->dev, "ch%u: cannot enable clock\n",
325 ch->index);
326 goto err0;
327 }
328
329 /* make sure channel is disabled */
330 sh_cmt_start_stop_ch(ch, 0);
331
332 /* configure channel, periodic mode and maximum timeout */
333 if (ch->cmt->info->width == 16) {
334 sh_cmt_write_cmcsr(ch, SH_CMT16_CMCSR_CMIE |
335 SH_CMT16_CMCSR_CKS512);
336 } else {
337 sh_cmt_write_cmcsr(ch, SH_CMT32_CMCSR_CMM |
338 SH_CMT32_CMCSR_CMTOUT_IE |
339 SH_CMT32_CMCSR_CMR_IRQ |
340 SH_CMT32_CMCSR_CKS_RCLK8);
341 }
342
343 sh_cmt_write_cmcor(ch, 0xffffffff);
344 sh_cmt_write_cmcnt(ch, 0);
345
346 /*
347 * According to the sh73a0 user's manual, as CMCNT can be operated
348 * only by the RCLK (Pseudo 32 KHz), there's one restriction on
349 * modifying CMCNT register; two RCLK cycles are necessary before
350 * this register is either read or any modification of the value
351 * it holds is reflected in the LSI's actual operation.
352 *
353 * While at it, we're supposed to clear out the CMCNT as of this
354 * moment, so make sure it's processed properly here. This will
355 * take RCLKx2 at maximum.
356 */
357 for (k = 0; k < 100; k++) {
358 if (!sh_cmt_read_cmcnt(ch))
359 break;
360 udelay(1);
361 }
362
363 if (sh_cmt_read_cmcnt(ch)) {
364 dev_err(&ch->cmt->pdev->dev, "ch%u: cannot clear CMCNT\n",
365 ch->index);
366 ret = -ETIMEDOUT;
367 goto err1;
368 }
369
370 /* enable channel */
371 sh_cmt_start_stop_ch(ch, 1);
372 return 0;
373 err1:
374 /* stop clock */
375 clk_disable(ch->cmt->clk);
376
377 err0:
378 return ret;
379}
380
381static void sh_cmt_disable(struct sh_cmt_channel *ch)
382{
383 /* disable channel */
384 sh_cmt_start_stop_ch(ch, 0);
385
386 /* disable interrupts in CMT block */
387 sh_cmt_write_cmcsr(ch, 0);
388
389 /* stop clock */
390 clk_disable(ch->cmt->clk);
391
392 dev_pm_syscore_device(&ch->cmt->pdev->dev, false);
393 pm_runtime_put(&ch->cmt->pdev->dev);
394}
395
396/* private flags */
397#define FLAG_CLOCKEVENT (1 << 0)
398#define FLAG_CLOCKSOURCE (1 << 1)
399#define FLAG_REPROGRAM (1 << 2)
400#define FLAG_SKIPEVENT (1 << 3)
401#define FLAG_IRQCONTEXT (1 << 4)
402
403static void sh_cmt_clock_event_program_verify(struct sh_cmt_channel *ch,
404 int absolute)
405{
406 u32 value = ch->next_match_value;
407 u32 new_match;
408 u32 delay = 0;
409 u32 now = 0;
410 u32 has_wrapped;
411
412 now = sh_cmt_get_counter(ch, &has_wrapped);
413 ch->flags |= FLAG_REPROGRAM; /* force reprogram */
414
415 if (has_wrapped) {
416 /* we're competing with the interrupt handler.
417 * -> let the interrupt handler reprogram the timer.
418 * -> interrupt number two handles the event.
419 */
420 ch->flags |= FLAG_SKIPEVENT;
421 return;
422 }
423
424 if (absolute)
425 now = 0;
426
427 do {
428 /* reprogram the timer hardware,
429 * but don't save the new match value yet.
430 */
431 new_match = now + value + delay;
432 if (new_match > ch->max_match_value)
433 new_match = ch->max_match_value;
434
435 sh_cmt_write_cmcor(ch, new_match);
436
437 now = sh_cmt_get_counter(ch, &has_wrapped);
438 if (has_wrapped && (new_match > ch->match_value)) {
439 /* we are changing to a greater match value,
440 * so this wrap must be caused by the counter
441 * matching the old value.
442 * -> first interrupt reprograms the timer.
443 * -> interrupt number two handles the event.
444 */
445 ch->flags |= FLAG_SKIPEVENT;
446 break;
447 }
448
449 if (has_wrapped) {
450 /* we are changing to a smaller match value,
451 * so the wrap must be caused by the counter
452 * matching the new value.
453 * -> save programmed match value.
454 * -> let isr handle the event.
455 */
456 ch->match_value = new_match;
457 break;
458 }
459
460 /* be safe: verify hardware settings */
461 if (now < new_match) {
462 /* timer value is below match value, all good.
463 * this makes sure we won't miss any match events.
464 * -> save programmed match value.
465 * -> let isr handle the event.
466 */
467 ch->match_value = new_match;
468 break;
469 }
470
471 /* the counter has reached a value greater
472 * than our new match value. and since the
473 * has_wrapped flag isn't set we must have
474 * programmed a too close event.
475 * -> increase delay and retry.
476 */
477 if (delay)
478 delay <<= 1;
479 else
480 delay = 1;
481
482 if (!delay)
483 dev_warn(&ch->cmt->pdev->dev, "ch%u: too long delay\n",
484 ch->index);
485
486 } while (delay);
487}
488
489static void __sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta)
490{
491 if (delta > ch->max_match_value)
492 dev_warn(&ch->cmt->pdev->dev, "ch%u: delta out of range\n",
493 ch->index);
494
495 ch->next_match_value = delta;
496 sh_cmt_clock_event_program_verify(ch, 0);
497}
498
499static void sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta)
500{
501 unsigned long flags;
502
503 raw_spin_lock_irqsave(&ch->lock, flags);
504 __sh_cmt_set_next(ch, delta);
505 raw_spin_unlock_irqrestore(&ch->lock, flags);
506}
507
508static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
509{
510 struct sh_cmt_channel *ch = dev_id;
511
512 /* clear flags */
513 sh_cmt_write_cmcsr(ch, sh_cmt_read_cmcsr(ch) &
514 ch->cmt->info->clear_bits);
515
516 /* update clock source counter to begin with if enabled
517 * the wrap flag should be cleared by the timer specific
518 * isr before we end up here.
519 */
520 if (ch->flags & FLAG_CLOCKSOURCE)
521 ch->total_cycles += ch->match_value + 1;
522
523 if (!(ch->flags & FLAG_REPROGRAM))
524 ch->next_match_value = ch->max_match_value;
525
526 ch->flags |= FLAG_IRQCONTEXT;
527
528 if (ch->flags & FLAG_CLOCKEVENT) {
529 if (!(ch->flags & FLAG_SKIPEVENT)) {
530 if (clockevent_state_oneshot(&ch->ced)) {
531 ch->next_match_value = ch->max_match_value;
532 ch->flags |= FLAG_REPROGRAM;
533 }
534
535 ch->ced.event_handler(&ch->ced);
536 }
537 }
538
539 ch->flags &= ~FLAG_SKIPEVENT;
540
541 if (ch->flags & FLAG_REPROGRAM) {
542 ch->flags &= ~FLAG_REPROGRAM;
543 sh_cmt_clock_event_program_verify(ch, 1);
544
545 if (ch->flags & FLAG_CLOCKEVENT)
546 if ((clockevent_state_shutdown(&ch->ced))
547 || (ch->match_value == ch->next_match_value))
548 ch->flags &= ~FLAG_REPROGRAM;
549 }
550
551 ch->flags &= ~FLAG_IRQCONTEXT;
552
553 return IRQ_HANDLED;
554}
555
556static int sh_cmt_start(struct sh_cmt_channel *ch, unsigned long flag)
557{
558 int ret = 0;
559 unsigned long flags;
560
561 raw_spin_lock_irqsave(&ch->lock, flags);
562
563 if (!(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
564 ret = sh_cmt_enable(ch);
565
566 if (ret)
567 goto out;
568 ch->flags |= flag;
569
570 /* setup timeout if no clockevent */
571 if ((flag == FLAG_CLOCKSOURCE) && (!(ch->flags & FLAG_CLOCKEVENT)))
572 __sh_cmt_set_next(ch, ch->max_match_value);
573 out:
574 raw_spin_unlock_irqrestore(&ch->lock, flags);
575
576 return ret;
577}
578
579static void sh_cmt_stop(struct sh_cmt_channel *ch, unsigned long flag)
580{
581 unsigned long flags;
582 unsigned long f;
583
584 raw_spin_lock_irqsave(&ch->lock, flags);
585
586 f = ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
587 ch->flags &= ~flag;
588
589 if (f && !(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
590 sh_cmt_disable(ch);
591
592 /* adjust the timeout to maximum if only clocksource left */
593 if ((flag == FLAG_CLOCKEVENT) && (ch->flags & FLAG_CLOCKSOURCE))
594 __sh_cmt_set_next(ch, ch->max_match_value);
595
596 raw_spin_unlock_irqrestore(&ch->lock, flags);
597}
598
599static struct sh_cmt_channel *cs_to_sh_cmt(struct clocksource *cs)
600{
601 return container_of(cs, struct sh_cmt_channel, cs);
602}
603
604static u64 sh_cmt_clocksource_read(struct clocksource *cs)
605{
606 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
607 unsigned long flags;
608 u32 has_wrapped;
609 u64 value;
610 u32 raw;
611
612 raw_spin_lock_irqsave(&ch->lock, flags);
613 value = ch->total_cycles;
614 raw = sh_cmt_get_counter(ch, &has_wrapped);
615
616 if (unlikely(has_wrapped))
617 raw += ch->match_value + 1;
618 raw_spin_unlock_irqrestore(&ch->lock, flags);
619
620 return value + raw;
621}
622
623static int sh_cmt_clocksource_enable(struct clocksource *cs)
624{
625 int ret;
626 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
627
628 WARN_ON(ch->cs_enabled);
629
630 ch->total_cycles = 0;
631
632 ret = sh_cmt_start(ch, FLAG_CLOCKSOURCE);
633 if (!ret)
634 ch->cs_enabled = true;
635
636 return ret;
637}
638
639static void sh_cmt_clocksource_disable(struct clocksource *cs)
640{
641 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
642
643 WARN_ON(!ch->cs_enabled);
644
645 sh_cmt_stop(ch, FLAG_CLOCKSOURCE);
646 ch->cs_enabled = false;
647}
648
649static void sh_cmt_clocksource_suspend(struct clocksource *cs)
650{
651 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
652
653 if (!ch->cs_enabled)
654 return;
655
656 sh_cmt_stop(ch, FLAG_CLOCKSOURCE);
657 pm_genpd_syscore_poweroff(&ch->cmt->pdev->dev);
658}
659
660static void sh_cmt_clocksource_resume(struct clocksource *cs)
661{
662 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
663
664 if (!ch->cs_enabled)
665 return;
666
667 pm_genpd_syscore_poweron(&ch->cmt->pdev->dev);
668 sh_cmt_start(ch, FLAG_CLOCKSOURCE);
669}
670
671static int sh_cmt_register_clocksource(struct sh_cmt_channel *ch,
672 const char *name)
673{
674 struct clocksource *cs = &ch->cs;
675
676 cs->name = name;
677 cs->rating = 125;
678 cs->read = sh_cmt_clocksource_read;
679 cs->enable = sh_cmt_clocksource_enable;
680 cs->disable = sh_cmt_clocksource_disable;
681 cs->suspend = sh_cmt_clocksource_suspend;
682 cs->resume = sh_cmt_clocksource_resume;
683 cs->mask = CLOCKSOURCE_MASK(sizeof(u64) * 8);
684 cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
685
686 dev_info(&ch->cmt->pdev->dev, "ch%u: used as clock source\n",
687 ch->index);
688
689 clocksource_register_hz(cs, ch->cmt->rate);
690 return 0;
691}
692
693static struct sh_cmt_channel *ced_to_sh_cmt(struct clock_event_device *ced)
694{
695 return container_of(ced, struct sh_cmt_channel, ced);
696}
697
698static void sh_cmt_clock_event_start(struct sh_cmt_channel *ch, int periodic)
699{
700 sh_cmt_start(ch, FLAG_CLOCKEVENT);
701
702 if (periodic)
703 sh_cmt_set_next(ch, ((ch->cmt->rate + HZ/2) / HZ) - 1);
704 else
705 sh_cmt_set_next(ch, ch->max_match_value);
706}
707
708static int sh_cmt_clock_event_shutdown(struct clock_event_device *ced)
709{
710 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
711
712 sh_cmt_stop(ch, FLAG_CLOCKEVENT);
713 return 0;
714}
715
716static int sh_cmt_clock_event_set_state(struct clock_event_device *ced,
717 int periodic)
718{
719 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
720
721 /* deal with old setting first */
722 if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
723 sh_cmt_stop(ch, FLAG_CLOCKEVENT);
724
725 dev_info(&ch->cmt->pdev->dev, "ch%u: used for %s clock events\n",
726 ch->index, periodic ? "periodic" : "oneshot");
727 sh_cmt_clock_event_start(ch, periodic);
728 return 0;
729}
730
731static int sh_cmt_clock_event_set_oneshot(struct clock_event_device *ced)
732{
733 return sh_cmt_clock_event_set_state(ced, 0);
734}
735
736static int sh_cmt_clock_event_set_periodic(struct clock_event_device *ced)
737{
738 return sh_cmt_clock_event_set_state(ced, 1);
739}
740
741static int sh_cmt_clock_event_next(unsigned long delta,
742 struct clock_event_device *ced)
743{
744 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
745
746 BUG_ON(!clockevent_state_oneshot(ced));
747 if (likely(ch->flags & FLAG_IRQCONTEXT))
748 ch->next_match_value = delta - 1;
749 else
750 sh_cmt_set_next(ch, delta - 1);
751
752 return 0;
753}
754
755static void sh_cmt_clock_event_suspend(struct clock_event_device *ced)
756{
757 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
758
759 pm_genpd_syscore_poweroff(&ch->cmt->pdev->dev);
760 clk_unprepare(ch->cmt->clk);
761}
762
763static void sh_cmt_clock_event_resume(struct clock_event_device *ced)
764{
765 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
766
767 clk_prepare(ch->cmt->clk);
768 pm_genpd_syscore_poweron(&ch->cmt->pdev->dev);
769}
770
771static int sh_cmt_register_clockevent(struct sh_cmt_channel *ch,
772 const char *name)
773{
774 struct clock_event_device *ced = &ch->ced;
775 int irq;
776 int ret;
777
778 irq = platform_get_irq(ch->cmt->pdev, ch->index);
779 if (irq < 0)
780 return irq;
781
782 ret = request_irq(irq, sh_cmt_interrupt,
783 IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
784 dev_name(&ch->cmt->pdev->dev), ch);
785 if (ret) {
786 dev_err(&ch->cmt->pdev->dev, "ch%u: failed to request irq %d\n",
787 ch->index, irq);
788 return ret;
789 }
790
791 ced->name = name;
792 ced->features = CLOCK_EVT_FEAT_PERIODIC;
793 ced->features |= CLOCK_EVT_FEAT_ONESHOT;
794 ced->rating = 125;
795 ced->cpumask = cpu_possible_mask;
796 ced->set_next_event = sh_cmt_clock_event_next;
797 ced->set_state_shutdown = sh_cmt_clock_event_shutdown;
798 ced->set_state_periodic = sh_cmt_clock_event_set_periodic;
799 ced->set_state_oneshot = sh_cmt_clock_event_set_oneshot;
800 ced->suspend = sh_cmt_clock_event_suspend;
801 ced->resume = sh_cmt_clock_event_resume;
802
803 /* TODO: calculate good shift from rate and counter bit width */
804 ced->shift = 32;
805 ced->mult = div_sc(ch->cmt->rate, NSEC_PER_SEC, ced->shift);
806 ced->max_delta_ns = clockevent_delta2ns(ch->max_match_value, ced);
807 ced->max_delta_ticks = ch->max_match_value;
808 ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
809 ced->min_delta_ticks = 0x1f;
810
811 dev_info(&ch->cmt->pdev->dev, "ch%u: used for clock events\n",
812 ch->index);
813 clockevents_register_device(ced);
814
815 return 0;
816}
817
818static int sh_cmt_register(struct sh_cmt_channel *ch, const char *name,
819 bool clockevent, bool clocksource)
820{
821 int ret;
822
823 if (clockevent) {
824 ch->cmt->has_clockevent = true;
825 ret = sh_cmt_register_clockevent(ch, name);
826 if (ret < 0)
827 return ret;
828 }
829
830 if (clocksource) {
831 ch->cmt->has_clocksource = true;
832 sh_cmt_register_clocksource(ch, name);
833 }
834
835 return 0;
836}
837
838static int sh_cmt_setup_channel(struct sh_cmt_channel *ch, unsigned int index,
839 unsigned int hwidx, bool clockevent,
840 bool clocksource, struct sh_cmt_device *cmt)
841{
842 int ret;
843
844 /* Skip unused channels. */
845 if (!clockevent && !clocksource)
846 return 0;
847
848 ch->cmt = cmt;
849 ch->index = index;
850 ch->hwidx = hwidx;
851 ch->timer_bit = hwidx;
852
853 /*
854 * Compute the address of the channel control register block. For the
855 * timers with a per-channel start/stop register, compute its address
856 * as well.
857 */
858 switch (cmt->info->model) {
859 case SH_CMT_16BIT:
860 ch->ioctrl = cmt->mapbase + 2 + ch->hwidx * 6;
861 break;
862 case SH_CMT_32BIT:
863 case SH_CMT_48BIT:
864 ch->ioctrl = cmt->mapbase + 0x10 + ch->hwidx * 0x10;
865 break;
866 case SH_CMT0_RCAR_GEN2:
867 case SH_CMT1_RCAR_GEN2:
868 ch->iostart = cmt->mapbase + ch->hwidx * 0x100;
869 ch->ioctrl = ch->iostart + 0x10;
870 ch->timer_bit = 0;
871 break;
872 }
873
874 if (cmt->info->width == (sizeof(ch->max_match_value) * 8))
875 ch->max_match_value = ~0;
876 else
877 ch->max_match_value = (1 << cmt->info->width) - 1;
878
879 ch->match_value = ch->max_match_value;
880 raw_spin_lock_init(&ch->lock);
881
882 ret = sh_cmt_register(ch, dev_name(&cmt->pdev->dev),
883 clockevent, clocksource);
884 if (ret) {
885 dev_err(&cmt->pdev->dev, "ch%u: registration failed\n",
886 ch->index);
887 return ret;
888 }
889 ch->cs_enabled = false;
890
891 return 0;
892}
893
894static int sh_cmt_map_memory(struct sh_cmt_device *cmt)
895{
896 struct resource *mem;
897
898 mem = platform_get_resource(cmt->pdev, IORESOURCE_MEM, 0);
899 if (!mem) {
900 dev_err(&cmt->pdev->dev, "failed to get I/O memory\n");
901 return -ENXIO;
902 }
903
904 cmt->mapbase = ioremap_nocache(mem->start, resource_size(mem));
905 if (cmt->mapbase == NULL) {
906 dev_err(&cmt->pdev->dev, "failed to remap I/O memory\n");
907 return -ENXIO;
908 }
909
910 return 0;
911}
912
913static const struct platform_device_id sh_cmt_id_table[] = {
914 { "sh-cmt-16", (kernel_ulong_t)&sh_cmt_info[SH_CMT_16BIT] },
915 { "sh-cmt-32", (kernel_ulong_t)&sh_cmt_info[SH_CMT_32BIT] },
916 { }
917};
918MODULE_DEVICE_TABLE(platform, sh_cmt_id_table);
919
920static const struct of_device_id sh_cmt_of_table[] __maybe_unused = {
921 {
922 /* deprecated, preserved for backward compatibility */
923 .compatible = "renesas,cmt-48",
924 .data = &sh_cmt_info[SH_CMT_48BIT]
925 },
926 {
927 /* deprecated, preserved for backward compatibility */
928 .compatible = "renesas,cmt-48-gen2",
929 .data = &sh_cmt_info[SH_CMT0_RCAR_GEN2]
930 },
931 {
932 .compatible = "renesas,r8a7740-cmt1",
933 .data = &sh_cmt_info[SH_CMT_48BIT]
934 },
935 {
936 .compatible = "renesas,sh73a0-cmt1",
937 .data = &sh_cmt_info[SH_CMT_48BIT]
938 },
939 {
940 .compatible = "renesas,rcar-gen2-cmt0",
941 .data = &sh_cmt_info[SH_CMT0_RCAR_GEN2]
942 },
943 {
944 .compatible = "renesas,rcar-gen2-cmt1",
945 .data = &sh_cmt_info[SH_CMT1_RCAR_GEN2]
946 },
947 {
948 .compatible = "renesas,rcar-gen3-cmt0",
949 .data = &sh_cmt_info[SH_CMT0_RCAR_GEN2]
950 },
951 {
952 .compatible = "renesas,rcar-gen3-cmt1",
953 .data = &sh_cmt_info[SH_CMT1_RCAR_GEN2]
954 },
955 { }
956};
957MODULE_DEVICE_TABLE(of, sh_cmt_of_table);
958
959static int sh_cmt_setup(struct sh_cmt_device *cmt, struct platform_device *pdev)
960{
961 unsigned int mask;
962 unsigned int i;
963 int ret;
964
965 cmt->pdev = pdev;
966 raw_spin_lock_init(&cmt->lock);
967
968 if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
969 cmt->info = of_device_get_match_data(&pdev->dev);
970 cmt->hw_channels = cmt->info->channels_mask;
971 } else if (pdev->dev.platform_data) {
972 struct sh_timer_config *cfg = pdev->dev.platform_data;
973 const struct platform_device_id *id = pdev->id_entry;
974
975 cmt->info = (const struct sh_cmt_info *)id->driver_data;
976 cmt->hw_channels = cfg->channels_mask;
977 } else {
978 dev_err(&cmt->pdev->dev, "missing platform data\n");
979 return -ENXIO;
980 }
981
982 /* Get hold of clock. */
983 cmt->clk = clk_get(&cmt->pdev->dev, "fck");
984 if (IS_ERR(cmt->clk)) {
985 dev_err(&cmt->pdev->dev, "cannot get clock\n");
986 return PTR_ERR(cmt->clk);
987 }
988
989 ret = clk_prepare(cmt->clk);
990 if (ret < 0)
991 goto err_clk_put;
992
993 /* Determine clock rate. */
994 ret = clk_enable(cmt->clk);
995 if (ret < 0)
996 goto err_clk_unprepare;
997
998 if (cmt->info->width == 16)
999 cmt->rate = clk_get_rate(cmt->clk) / 512;
1000 else
1001 cmt->rate = clk_get_rate(cmt->clk) / 8;
1002
1003 clk_disable(cmt->clk);
1004
1005 /* Map the memory resource(s). */
1006 ret = sh_cmt_map_memory(cmt);
1007 if (ret < 0)
1008 goto err_clk_unprepare;
1009
1010 /* Allocate and setup the channels. */
1011 cmt->num_channels = hweight8(cmt->hw_channels);
1012 cmt->channels = kcalloc(cmt->num_channels, sizeof(*cmt->channels),
1013 GFP_KERNEL);
1014 if (cmt->channels == NULL) {
1015 ret = -ENOMEM;
1016 goto err_unmap;
1017 }
1018
1019 /*
1020 * Use the first channel as a clock event device and the second channel
1021 * as a clock source. If only one channel is available use it for both.
1022 */
1023 for (i = 0, mask = cmt->hw_channels; i < cmt->num_channels; ++i) {
1024 unsigned int hwidx = ffs(mask) - 1;
1025 bool clocksource = i == 1 || cmt->num_channels == 1;
1026 bool clockevent = i == 0;
1027
1028 ret = sh_cmt_setup_channel(&cmt->channels[i], i, hwidx,
1029 clockevent, clocksource, cmt);
1030 if (ret < 0)
1031 goto err_unmap;
1032
1033 mask &= ~(1 << hwidx);
1034 }
1035
1036 platform_set_drvdata(pdev, cmt);
1037
1038 return 0;
1039
1040err_unmap:
1041 kfree(cmt->channels);
1042 iounmap(cmt->mapbase);
1043err_clk_unprepare:
1044 clk_unprepare(cmt->clk);
1045err_clk_put:
1046 clk_put(cmt->clk);
1047 return ret;
1048}
1049
1050static int sh_cmt_probe(struct platform_device *pdev)
1051{
1052 struct sh_cmt_device *cmt = platform_get_drvdata(pdev);
1053 int ret;
1054
1055 if (!is_early_platform_device(pdev)) {
1056 pm_runtime_set_active(&pdev->dev);
1057 pm_runtime_enable(&pdev->dev);
1058 }
1059
1060 if (cmt) {
1061 dev_info(&pdev->dev, "kept as earlytimer\n");
1062 goto out;
1063 }
1064
1065 cmt = kzalloc(sizeof(*cmt), GFP_KERNEL);
1066 if (cmt == NULL)
1067 return -ENOMEM;
1068
1069 ret = sh_cmt_setup(cmt, pdev);
1070 if (ret) {
1071 kfree(cmt);
1072 pm_runtime_idle(&pdev->dev);
1073 return ret;
1074 }
1075 if (is_early_platform_device(pdev))
1076 return 0;
1077
1078 out:
1079 if (cmt->has_clockevent || cmt->has_clocksource)
1080 pm_runtime_irq_safe(&pdev->dev);
1081 else
1082 pm_runtime_idle(&pdev->dev);
1083
1084 return 0;
1085}
1086
1087static int sh_cmt_remove(struct platform_device *pdev)
1088{
1089 return -EBUSY; /* cannot unregister clockevent and clocksource */
1090}
1091
1092static struct platform_driver sh_cmt_device_driver = {
1093 .probe = sh_cmt_probe,
1094 .remove = sh_cmt_remove,
1095 .driver = {
1096 .name = "sh_cmt",
1097 .of_match_table = of_match_ptr(sh_cmt_of_table),
1098 },
1099 .id_table = sh_cmt_id_table,
1100};
1101
1102static int __init sh_cmt_init(void)
1103{
1104 return platform_driver_register(&sh_cmt_device_driver);
1105}
1106
1107static void __exit sh_cmt_exit(void)
1108{
1109 platform_driver_unregister(&sh_cmt_device_driver);
1110}
1111
1112early_platform_init("earlytimer", &sh_cmt_device_driver);
1113subsys_initcall(sh_cmt_init);
1114module_exit(sh_cmt_exit);
1115
1116MODULE_AUTHOR("Magnus Damm");
1117MODULE_DESCRIPTION("SuperH CMT Timer Driver");
1118MODULE_LICENSE("GPL v2");