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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
35struct sh_cmt_priv {
36 void __iomem *mapbase;
37 struct clk *clk;
38 unsigned long width; /* 16 or 32 bit version of hardware block */
39 unsigned long overflow_bit;
40 unsigned long clear_bits;
41 struct irqaction irqaction;
42 struct platform_device *pdev;
43
44 unsigned long flags;
45 unsigned long match_value;
46 unsigned long next_match_value;
47 unsigned long max_match_value;
48 unsigned long rate;
49 spinlock_t lock;
50 struct clock_event_device ced;
51 struct clocksource cs;
52 unsigned long total_cycles;
53};
54
55static DEFINE_SPINLOCK(sh_cmt_lock);
56
57#define CMSTR -1 /* shared register */
58#define CMCSR 0 /* channel register */
59#define CMCNT 1 /* channel register */
60#define CMCOR 2 /* channel register */
61
62static inline unsigned long sh_cmt_read(struct sh_cmt_priv *p, int reg_nr)
63{
64 struct sh_timer_config *cfg = p->pdev->dev.platform_data;
65 void __iomem *base = p->mapbase;
66 unsigned long offs;
67
68 if (reg_nr == CMSTR) {
69 offs = 0;
70 base -= cfg->channel_offset;
71 } else
72 offs = reg_nr;
73
74 if (p->width == 16)
75 offs <<= 1;
76 else {
77 offs <<= 2;
78 if ((reg_nr == CMCNT) || (reg_nr == CMCOR))
79 return ioread32(base + offs);
80 }
81
82 return ioread16(base + offs);
83}
84
85static inline void sh_cmt_write(struct sh_cmt_priv *p, int reg_nr,
86 unsigned long value)
87{
88 struct sh_timer_config *cfg = p->pdev->dev.platform_data;
89 void __iomem *base = p->mapbase;
90 unsigned long offs;
91
92 if (reg_nr == CMSTR) {
93 offs = 0;
94 base -= cfg->channel_offset;
95 } else
96 offs = reg_nr;
97
98 if (p->width == 16)
99 offs <<= 1;
100 else {
101 offs <<= 2;
102 if ((reg_nr == CMCNT) || (reg_nr == CMCOR)) {
103 iowrite32(value, base + offs);
104 return;
105 }
106 }
107
108 iowrite16(value, base + offs);
109}
110
111static unsigned long sh_cmt_get_counter(struct sh_cmt_priv *p,
112 int *has_wrapped)
113{
114 unsigned long v1, v2, v3;
115 int o1, o2;
116
117 o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
118
119 /* Make sure the timer value is stable. Stolen from acpi_pm.c */
120 do {
121 o2 = o1;
122 v1 = sh_cmt_read(p, CMCNT);
123 v2 = sh_cmt_read(p, CMCNT);
124 v3 = sh_cmt_read(p, CMCNT);
125 o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
126 } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
127 || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
128
129 *has_wrapped = o1;
130 return v2;
131}
132
133
134static void sh_cmt_start_stop_ch(struct sh_cmt_priv *p, int start)
135{
136 struct sh_timer_config *cfg = p->pdev->dev.platform_data;
137 unsigned long flags, value;
138
139 /* start stop register shared by multiple timer channels */
140 spin_lock_irqsave(&sh_cmt_lock, flags);
141 value = sh_cmt_read(p, CMSTR);
142
143 if (start)
144 value |= 1 << cfg->timer_bit;
145 else
146 value &= ~(1 << cfg->timer_bit);
147
148 sh_cmt_write(p, CMSTR, value);
149 spin_unlock_irqrestore(&sh_cmt_lock, flags);
150}
151
152static int sh_cmt_enable(struct sh_cmt_priv *p, unsigned long *rate)
153{
154 int k, ret;
155
156 /* enable clock */
157 ret = clk_enable(p->clk);
158 if (ret) {
159 dev_err(&p->pdev->dev, "cannot enable clock\n");
160 goto err0;
161 }
162
163 /* make sure channel is disabled */
164 sh_cmt_start_stop_ch(p, 0);
165
166 /* configure channel, periodic mode and maximum timeout */
167 if (p->width == 16) {
168 *rate = clk_get_rate(p->clk) / 512;
169 sh_cmt_write(p, CMCSR, 0x43);
170 } else {
171 *rate = clk_get_rate(p->clk) / 8;
172 sh_cmt_write(p, CMCSR, 0x01a4);
173 }
174
175 sh_cmt_write(p, CMCOR, 0xffffffff);
176 sh_cmt_write(p, CMCNT, 0);
177
178 /*
179 * According to the sh73a0 user's manual, as CMCNT can be operated
180 * only by the RCLK (Pseudo 32 KHz), there's one restriction on
181 * modifying CMCNT register; two RCLK cycles are necessary before
182 * this register is either read or any modification of the value
183 * it holds is reflected in the LSI's actual operation.
184 *
185 * While at it, we're supposed to clear out the CMCNT as of this
186 * moment, so make sure it's processed properly here. This will
187 * take RCLKx2 at maximum.
188 */
189 for (k = 0; k < 100; k++) {
190 if (!sh_cmt_read(p, CMCNT))
191 break;
192 udelay(1);
193 }
194
195 if (sh_cmt_read(p, CMCNT)) {
196 dev_err(&p->pdev->dev, "cannot clear CMCNT\n");
197 ret = -ETIMEDOUT;
198 goto err1;
199 }
200
201 /* enable channel */
202 sh_cmt_start_stop_ch(p, 1);
203 return 0;
204 err1:
205 /* stop clock */
206 clk_disable(p->clk);
207
208 err0:
209 return ret;
210}
211
212static void sh_cmt_disable(struct sh_cmt_priv *p)
213{
214 /* disable channel */
215 sh_cmt_start_stop_ch(p, 0);
216
217 /* disable interrupts in CMT block */
218 sh_cmt_write(p, CMCSR, 0);
219
220 /* stop clock */
221 clk_disable(p->clk);
222}
223
224/* private flags */
225#define FLAG_CLOCKEVENT (1 << 0)
226#define FLAG_CLOCKSOURCE (1 << 1)
227#define FLAG_REPROGRAM (1 << 2)
228#define FLAG_SKIPEVENT (1 << 3)
229#define FLAG_IRQCONTEXT (1 << 4)
230
231static void sh_cmt_clock_event_program_verify(struct sh_cmt_priv *p,
232 int absolute)
233{
234 unsigned long new_match;
235 unsigned long value = p->next_match_value;
236 unsigned long delay = 0;
237 unsigned long now = 0;
238 int has_wrapped;
239
240 now = sh_cmt_get_counter(p, &has_wrapped);
241 p->flags |= FLAG_REPROGRAM; /* force reprogram */
242
243 if (has_wrapped) {
244 /* we're competing with the interrupt handler.
245 * -> let the interrupt handler reprogram the timer.
246 * -> interrupt number two handles the event.
247 */
248 p->flags |= FLAG_SKIPEVENT;
249 return;
250 }
251
252 if (absolute)
253 now = 0;
254
255 do {
256 /* reprogram the timer hardware,
257 * but don't save the new match value yet.
258 */
259 new_match = now + value + delay;
260 if (new_match > p->max_match_value)
261 new_match = p->max_match_value;
262
263 sh_cmt_write(p, CMCOR, new_match);
264
265 now = sh_cmt_get_counter(p, &has_wrapped);
266 if (has_wrapped && (new_match > p->match_value)) {
267 /* we are changing to a greater match value,
268 * so this wrap must be caused by the counter
269 * matching the old value.
270 * -> first interrupt reprograms the timer.
271 * -> interrupt number two handles the event.
272 */
273 p->flags |= FLAG_SKIPEVENT;
274 break;
275 }
276
277 if (has_wrapped) {
278 /* we are changing to a smaller match value,
279 * so the wrap must be caused by the counter
280 * matching the new value.
281 * -> save programmed match value.
282 * -> let isr handle the event.
283 */
284 p->match_value = new_match;
285 break;
286 }
287
288 /* be safe: verify hardware settings */
289 if (now < new_match) {
290 /* timer value is below match value, all good.
291 * this makes sure we won't miss any match events.
292 * -> save programmed match value.
293 * -> let isr handle the event.
294 */
295 p->match_value = new_match;
296 break;
297 }
298
299 /* the counter has reached a value greater
300 * than our new match value. and since the
301 * has_wrapped flag isn't set we must have
302 * programmed a too close event.
303 * -> increase delay and retry.
304 */
305 if (delay)
306 delay <<= 1;
307 else
308 delay = 1;
309
310 if (!delay)
311 dev_warn(&p->pdev->dev, "too long delay\n");
312
313 } while (delay);
314}
315
316static void __sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)
317{
318 if (delta > p->max_match_value)
319 dev_warn(&p->pdev->dev, "delta out of range\n");
320
321 p->next_match_value = delta;
322 sh_cmt_clock_event_program_verify(p, 0);
323}
324
325static void sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)
326{
327 unsigned long flags;
328
329 spin_lock_irqsave(&p->lock, flags);
330 __sh_cmt_set_next(p, delta);
331 spin_unlock_irqrestore(&p->lock, flags);
332}
333
334static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
335{
336 struct sh_cmt_priv *p = dev_id;
337
338 /* clear flags */
339 sh_cmt_write(p, CMCSR, sh_cmt_read(p, CMCSR) & p->clear_bits);
340
341 /* update clock source counter to begin with if enabled
342 * the wrap flag should be cleared by the timer specific
343 * isr before we end up here.
344 */
345 if (p->flags & FLAG_CLOCKSOURCE)
346 p->total_cycles += p->match_value + 1;
347
348 if (!(p->flags & FLAG_REPROGRAM))
349 p->next_match_value = p->max_match_value;
350
351 p->flags |= FLAG_IRQCONTEXT;
352
353 if (p->flags & FLAG_CLOCKEVENT) {
354 if (!(p->flags & FLAG_SKIPEVENT)) {
355 if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT) {
356 p->next_match_value = p->max_match_value;
357 p->flags |= FLAG_REPROGRAM;
358 }
359
360 p->ced.event_handler(&p->ced);
361 }
362 }
363
364 p->flags &= ~FLAG_SKIPEVENT;
365
366 if (p->flags & FLAG_REPROGRAM) {
367 p->flags &= ~FLAG_REPROGRAM;
368 sh_cmt_clock_event_program_verify(p, 1);
369
370 if (p->flags & FLAG_CLOCKEVENT)
371 if ((p->ced.mode == CLOCK_EVT_MODE_SHUTDOWN)
372 || (p->match_value == p->next_match_value))
373 p->flags &= ~FLAG_REPROGRAM;
374 }
375
376 p->flags &= ~FLAG_IRQCONTEXT;
377
378 return IRQ_HANDLED;
379}
380
381static int sh_cmt_start(struct sh_cmt_priv *p, unsigned long flag)
382{
383 int ret = 0;
384 unsigned long flags;
385
386 spin_lock_irqsave(&p->lock, flags);
387
388 if (!(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
389 ret = sh_cmt_enable(p, &p->rate);
390
391 if (ret)
392 goto out;
393 p->flags |= flag;
394
395 /* setup timeout if no clockevent */
396 if ((flag == FLAG_CLOCKSOURCE) && (!(p->flags & FLAG_CLOCKEVENT)))
397 __sh_cmt_set_next(p, p->max_match_value);
398 out:
399 spin_unlock_irqrestore(&p->lock, flags);
400
401 return ret;
402}
403
404static void sh_cmt_stop(struct sh_cmt_priv *p, unsigned long flag)
405{
406 unsigned long flags;
407 unsigned long f;
408
409 spin_lock_irqsave(&p->lock, flags);
410
411 f = p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
412 p->flags &= ~flag;
413
414 if (f && !(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
415 sh_cmt_disable(p);
416
417 /* adjust the timeout to maximum if only clocksource left */
418 if ((flag == FLAG_CLOCKEVENT) && (p->flags & FLAG_CLOCKSOURCE))
419 __sh_cmt_set_next(p, p->max_match_value);
420
421 spin_unlock_irqrestore(&p->lock, flags);
422}
423
424static struct sh_cmt_priv *cs_to_sh_cmt(struct clocksource *cs)
425{
426 return container_of(cs, struct sh_cmt_priv, cs);
427}
428
429static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
430{
431 struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
432 unsigned long flags, raw;
433 unsigned long value;
434 int has_wrapped;
435
436 spin_lock_irqsave(&p->lock, flags);
437 value = p->total_cycles;
438 raw = sh_cmt_get_counter(p, &has_wrapped);
439
440 if (unlikely(has_wrapped))
441 raw += p->match_value + 1;
442 spin_unlock_irqrestore(&p->lock, flags);
443
444 return value + raw;
445}
446
447static int sh_cmt_clocksource_enable(struct clocksource *cs)
448{
449 int ret;
450 struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
451
452 p->total_cycles = 0;
453
454 ret = sh_cmt_start(p, FLAG_CLOCKSOURCE);
455 if (!ret)
456 __clocksource_updatefreq_hz(cs, p->rate);
457 return ret;
458}
459
460static void sh_cmt_clocksource_disable(struct clocksource *cs)
461{
462 sh_cmt_stop(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
463}
464
465static void sh_cmt_clocksource_resume(struct clocksource *cs)
466{
467 sh_cmt_start(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
468}
469
470static int sh_cmt_register_clocksource(struct sh_cmt_priv *p,
471 char *name, unsigned long rating)
472{
473 struct clocksource *cs = &p->cs;
474
475 cs->name = name;
476 cs->rating = rating;
477 cs->read = sh_cmt_clocksource_read;
478 cs->enable = sh_cmt_clocksource_enable;
479 cs->disable = sh_cmt_clocksource_disable;
480 cs->suspend = sh_cmt_clocksource_disable;
481 cs->resume = sh_cmt_clocksource_resume;
482 cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
483 cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
484
485 dev_info(&p->pdev->dev, "used as clock source\n");
486
487 /* Register with dummy 1 Hz value, gets updated in ->enable() */
488 clocksource_register_hz(cs, 1);
489 return 0;
490}
491
492static struct sh_cmt_priv *ced_to_sh_cmt(struct clock_event_device *ced)
493{
494 return container_of(ced, struct sh_cmt_priv, ced);
495}
496
497static void sh_cmt_clock_event_start(struct sh_cmt_priv *p, int periodic)
498{
499 struct clock_event_device *ced = &p->ced;
500
501 sh_cmt_start(p, FLAG_CLOCKEVENT);
502
503 /* TODO: calculate good shift from rate and counter bit width */
504
505 ced->shift = 32;
506 ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
507 ced->max_delta_ns = clockevent_delta2ns(p->max_match_value, ced);
508 ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
509
510 if (periodic)
511 sh_cmt_set_next(p, ((p->rate + HZ/2) / HZ) - 1);
512 else
513 sh_cmt_set_next(p, p->max_match_value);
514}
515
516static void sh_cmt_clock_event_mode(enum clock_event_mode mode,
517 struct clock_event_device *ced)
518{
519 struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
520
521 /* deal with old setting first */
522 switch (ced->mode) {
523 case CLOCK_EVT_MODE_PERIODIC:
524 case CLOCK_EVT_MODE_ONESHOT:
525 sh_cmt_stop(p, FLAG_CLOCKEVENT);
526 break;
527 default:
528 break;
529 }
530
531 switch (mode) {
532 case CLOCK_EVT_MODE_PERIODIC:
533 dev_info(&p->pdev->dev, "used for periodic clock events\n");
534 sh_cmt_clock_event_start(p, 1);
535 break;
536 case CLOCK_EVT_MODE_ONESHOT:
537 dev_info(&p->pdev->dev, "used for oneshot clock events\n");
538 sh_cmt_clock_event_start(p, 0);
539 break;
540 case CLOCK_EVT_MODE_SHUTDOWN:
541 case CLOCK_EVT_MODE_UNUSED:
542 sh_cmt_stop(p, FLAG_CLOCKEVENT);
543 break;
544 default:
545 break;
546 }
547}
548
549static int sh_cmt_clock_event_next(unsigned long delta,
550 struct clock_event_device *ced)
551{
552 struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
553
554 BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
555 if (likely(p->flags & FLAG_IRQCONTEXT))
556 p->next_match_value = delta - 1;
557 else
558 sh_cmt_set_next(p, delta - 1);
559
560 return 0;
561}
562
563static void sh_cmt_register_clockevent(struct sh_cmt_priv *p,
564 char *name, unsigned long rating)
565{
566 struct clock_event_device *ced = &p->ced;
567
568 memset(ced, 0, sizeof(*ced));
569
570 ced->name = name;
571 ced->features = CLOCK_EVT_FEAT_PERIODIC;
572 ced->features |= CLOCK_EVT_FEAT_ONESHOT;
573 ced->rating = rating;
574 ced->cpumask = cpumask_of(0);
575 ced->set_next_event = sh_cmt_clock_event_next;
576 ced->set_mode = sh_cmt_clock_event_mode;
577
578 dev_info(&p->pdev->dev, "used for clock events\n");
579 clockevents_register_device(ced);
580}
581
582static int sh_cmt_register(struct sh_cmt_priv *p, char *name,
583 unsigned long clockevent_rating,
584 unsigned long clocksource_rating)
585{
586 if (p->width == (sizeof(p->max_match_value) * 8))
587 p->max_match_value = ~0;
588 else
589 p->max_match_value = (1 << p->width) - 1;
590
591 p->match_value = p->max_match_value;
592 spin_lock_init(&p->lock);
593
594 if (clockevent_rating)
595 sh_cmt_register_clockevent(p, name, clockevent_rating);
596
597 if (clocksource_rating)
598 sh_cmt_register_clocksource(p, name, clocksource_rating);
599
600 return 0;
601}
602
603static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
604{
605 struct sh_timer_config *cfg = pdev->dev.platform_data;
606 struct resource *res;
607 int irq, ret;
608 ret = -ENXIO;
609
610 memset(p, 0, sizeof(*p));
611 p->pdev = pdev;
612
613 if (!cfg) {
614 dev_err(&p->pdev->dev, "missing platform data\n");
615 goto err0;
616 }
617
618 platform_set_drvdata(pdev, p);
619
620 res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
621 if (!res) {
622 dev_err(&p->pdev->dev, "failed to get I/O memory\n");
623 goto err0;
624 }
625
626 irq = platform_get_irq(p->pdev, 0);
627 if (irq < 0) {
628 dev_err(&p->pdev->dev, "failed to get irq\n");
629 goto err0;
630 }
631
632 /* map memory, let mapbase point to our channel */
633 p->mapbase = ioremap_nocache(res->start, resource_size(res));
634 if (p->mapbase == NULL) {
635 dev_err(&p->pdev->dev, "failed to remap I/O memory\n");
636 goto err0;
637 }
638
639 /* request irq using setup_irq() (too early for request_irq()) */
640 p->irqaction.name = dev_name(&p->pdev->dev);
641 p->irqaction.handler = sh_cmt_interrupt;
642 p->irqaction.dev_id = p;
643 p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | \
644 IRQF_IRQPOLL | IRQF_NOBALANCING;
645
646 /* get hold of clock */
647 p->clk = clk_get(&p->pdev->dev, "cmt_fck");
648 if (IS_ERR(p->clk)) {
649 dev_err(&p->pdev->dev, "cannot get clock\n");
650 ret = PTR_ERR(p->clk);
651 goto err1;
652 }
653
654 if (resource_size(res) == 6) {
655 p->width = 16;
656 p->overflow_bit = 0x80;
657 p->clear_bits = ~0x80;
658 } else {
659 p->width = 32;
660 p->overflow_bit = 0x8000;
661 p->clear_bits = ~0xc000;
662 }
663
664 ret = sh_cmt_register(p, (char *)dev_name(&p->pdev->dev),
665 cfg->clockevent_rating,
666 cfg->clocksource_rating);
667 if (ret) {
668 dev_err(&p->pdev->dev, "registration failed\n");
669 goto err1;
670 }
671
672 ret = setup_irq(irq, &p->irqaction);
673 if (ret) {
674 dev_err(&p->pdev->dev, "failed to request irq %d\n", irq);
675 goto err1;
676 }
677
678 return 0;
679
680err1:
681 iounmap(p->mapbase);
682err0:
683 return ret;
684}
685
686static int __devinit sh_cmt_probe(struct platform_device *pdev)
687{
688 struct sh_cmt_priv *p = platform_get_drvdata(pdev);
689 int ret;
690
691 if (p) {
692 dev_info(&pdev->dev, "kept as earlytimer\n");
693 return 0;
694 }
695
696 p = kmalloc(sizeof(*p), GFP_KERNEL);
697 if (p == NULL) {
698 dev_err(&pdev->dev, "failed to allocate driver data\n");
699 return -ENOMEM;
700 }
701
702 ret = sh_cmt_setup(p, pdev);
703 if (ret) {
704 kfree(p);
705 platform_set_drvdata(pdev, NULL);
706 }
707 return ret;
708}
709
710static int __devexit sh_cmt_remove(struct platform_device *pdev)
711{
712 return -EBUSY; /* cannot unregister clockevent and clocksource */
713}
714
715static struct platform_driver sh_cmt_device_driver = {
716 .probe = sh_cmt_probe,
717 .remove = __devexit_p(sh_cmt_remove),
718 .driver = {
719 .name = "sh_cmt",
720 }
721};
722
723static int __init sh_cmt_init(void)
724{
725 return platform_driver_register(&sh_cmt_device_driver);
726}
727
728static void __exit sh_cmt_exit(void)
729{
730 platform_driver_unregister(&sh_cmt_device_driver);
731}
732
733early_platform_init("earlytimer", &sh_cmt_device_driver);
734module_init(sh_cmt_init);
735module_exit(sh_cmt_exit);
736
737MODULE_AUTHOR("Magnus Damm");
738MODULE_DESCRIPTION("SuperH CMT Timer Driver");
739MODULE_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
28#ifdef CONFIG_SUPERH
29#include <asm/platform_early.h>
30#endif
31
32struct sh_cmt_device;
33
34/*
35 * The CMT comes in 5 different identified flavours, depending not only on the
36 * SoC but also on the particular instance. The following table lists the main
37 * characteristics of those flavours.
38 *
39 * 16B 32B 32B-F 48B R-Car Gen2
40 * -----------------------------------------------------------------------------
41 * Channels 2 1/4 1 6 2/8
42 * Control Width 16 16 16 16 32
43 * Counter Width 16 32 32 32/48 32/48
44 * Shared Start/Stop Y Y Y Y N
45 *
46 * The r8a73a4 / R-Car Gen2 version has a per-channel start/stop register
47 * located in the channel registers block. All other versions have a shared
48 * start/stop register located in the global space.
49 *
50 * Channels are indexed from 0 to N-1 in the documentation. The channel index
51 * infers the start/stop bit position in the control register and the channel
52 * registers block address. Some CMT instances have a subset of channels
53 * available, in which case the index in the documentation doesn't match the
54 * "real" index as implemented in hardware. This is for instance the case with
55 * CMT0 on r8a7740, which is a 32-bit variant with a single channel numbered 0
56 * in the documentation but using start/stop bit 5 and having its registers
57 * block at 0x60.
58 *
59 * Similarly CMT0 on r8a73a4, r8a7790 and r8a7791, while implementing 32-bit
60 * channels only, is a 48-bit gen2 CMT with the 48-bit channels unavailable.
61 */
62
63enum sh_cmt_model {
64 SH_CMT_16BIT,
65 SH_CMT_32BIT,
66 SH_CMT_48BIT,
67 SH_CMT0_RCAR_GEN2,
68 SH_CMT1_RCAR_GEN2,
69};
70
71struct sh_cmt_info {
72 enum sh_cmt_model model;
73
74 unsigned int channels_mask;
75
76 unsigned long width; /* 16 or 32 bit version of hardware block */
77 u32 overflow_bit;
78 u32 clear_bits;
79
80 /* callbacks for CMSTR and CMCSR access */
81 u32 (*read_control)(void __iomem *base, unsigned long offs);
82 void (*write_control)(void __iomem *base, unsigned long offs,
83 u32 value);
84
85 /* callbacks for CMCNT and CMCOR access */
86 u32 (*read_count)(void __iomem *base, unsigned long offs);
87 void (*write_count)(void __iomem *base, unsigned long offs, u32 value);
88};
89
90struct sh_cmt_channel {
91 struct sh_cmt_device *cmt;
92
93 unsigned int index; /* Index in the documentation */
94 unsigned int hwidx; /* Real hardware index */
95
96 void __iomem *iostart;
97 void __iomem *ioctrl;
98
99 unsigned int timer_bit;
100 unsigned long flags;
101 u32 match_value;
102 u32 next_match_value;
103 u32 max_match_value;
104 raw_spinlock_t lock;
105 struct clock_event_device ced;
106 struct clocksource cs;
107 u64 total_cycles;
108 bool cs_enabled;
109};
110
111struct sh_cmt_device {
112 struct platform_device *pdev;
113
114 const struct sh_cmt_info *info;
115
116 void __iomem *mapbase;
117 struct clk *clk;
118 unsigned long rate;
119
120 raw_spinlock_t lock; /* Protect the shared start/stop register */
121
122 struct sh_cmt_channel *channels;
123 unsigned int num_channels;
124 unsigned int hw_channels;
125
126 bool has_clockevent;
127 bool has_clocksource;
128};
129
130#define SH_CMT16_CMCSR_CMF (1 << 7)
131#define SH_CMT16_CMCSR_CMIE (1 << 6)
132#define SH_CMT16_CMCSR_CKS8 (0 << 0)
133#define SH_CMT16_CMCSR_CKS32 (1 << 0)
134#define SH_CMT16_CMCSR_CKS128 (2 << 0)
135#define SH_CMT16_CMCSR_CKS512 (3 << 0)
136#define SH_CMT16_CMCSR_CKS_MASK (3 << 0)
137
138#define SH_CMT32_CMCSR_CMF (1 << 15)
139#define SH_CMT32_CMCSR_OVF (1 << 14)
140#define SH_CMT32_CMCSR_WRFLG (1 << 13)
141#define SH_CMT32_CMCSR_STTF (1 << 12)
142#define SH_CMT32_CMCSR_STPF (1 << 11)
143#define SH_CMT32_CMCSR_SSIE (1 << 10)
144#define SH_CMT32_CMCSR_CMS (1 << 9)
145#define SH_CMT32_CMCSR_CMM (1 << 8)
146#define SH_CMT32_CMCSR_CMTOUT_IE (1 << 7)
147#define SH_CMT32_CMCSR_CMR_NONE (0 << 4)
148#define SH_CMT32_CMCSR_CMR_DMA (1 << 4)
149#define SH_CMT32_CMCSR_CMR_IRQ (2 << 4)
150#define SH_CMT32_CMCSR_CMR_MASK (3 << 4)
151#define SH_CMT32_CMCSR_DBGIVD (1 << 3)
152#define SH_CMT32_CMCSR_CKS_RCLK8 (4 << 0)
153#define SH_CMT32_CMCSR_CKS_RCLK32 (5 << 0)
154#define SH_CMT32_CMCSR_CKS_RCLK128 (6 << 0)
155#define SH_CMT32_CMCSR_CKS_RCLK1 (7 << 0)
156#define SH_CMT32_CMCSR_CKS_MASK (7 << 0)
157
158static u32 sh_cmt_read16(void __iomem *base, unsigned long offs)
159{
160 return ioread16(base + (offs << 1));
161}
162
163static u32 sh_cmt_read32(void __iomem *base, unsigned long offs)
164{
165 return ioread32(base + (offs << 2));
166}
167
168static void sh_cmt_write16(void __iomem *base, unsigned long offs, u32 value)
169{
170 iowrite16(value, base + (offs << 1));
171}
172
173static void sh_cmt_write32(void __iomem *base, unsigned long offs, u32 value)
174{
175 iowrite32(value, base + (offs << 2));
176}
177
178static const struct sh_cmt_info sh_cmt_info[] = {
179 [SH_CMT_16BIT] = {
180 .model = SH_CMT_16BIT,
181 .width = 16,
182 .overflow_bit = SH_CMT16_CMCSR_CMF,
183 .clear_bits = ~SH_CMT16_CMCSR_CMF,
184 .read_control = sh_cmt_read16,
185 .write_control = sh_cmt_write16,
186 .read_count = sh_cmt_read16,
187 .write_count = sh_cmt_write16,
188 },
189 [SH_CMT_32BIT] = {
190 .model = SH_CMT_32BIT,
191 .width = 32,
192 .overflow_bit = SH_CMT32_CMCSR_CMF,
193 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
194 .read_control = sh_cmt_read16,
195 .write_control = sh_cmt_write16,
196 .read_count = sh_cmt_read32,
197 .write_count = sh_cmt_write32,
198 },
199 [SH_CMT_48BIT] = {
200 .model = SH_CMT_48BIT,
201 .channels_mask = 0x3f,
202 .width = 32,
203 .overflow_bit = SH_CMT32_CMCSR_CMF,
204 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
205 .read_control = sh_cmt_read32,
206 .write_control = sh_cmt_write32,
207 .read_count = sh_cmt_read32,
208 .write_count = sh_cmt_write32,
209 },
210 [SH_CMT0_RCAR_GEN2] = {
211 .model = SH_CMT0_RCAR_GEN2,
212 .channels_mask = 0x60,
213 .width = 32,
214 .overflow_bit = SH_CMT32_CMCSR_CMF,
215 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
216 .read_control = sh_cmt_read32,
217 .write_control = sh_cmt_write32,
218 .read_count = sh_cmt_read32,
219 .write_count = sh_cmt_write32,
220 },
221 [SH_CMT1_RCAR_GEN2] = {
222 .model = SH_CMT1_RCAR_GEN2,
223 .channels_mask = 0xff,
224 .width = 32,
225 .overflow_bit = SH_CMT32_CMCSR_CMF,
226 .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF),
227 .read_control = sh_cmt_read32,
228 .write_control = sh_cmt_write32,
229 .read_count = sh_cmt_read32,
230 .write_count = sh_cmt_write32,
231 },
232};
233
234#define CMCSR 0 /* channel register */
235#define CMCNT 1 /* channel register */
236#define CMCOR 2 /* channel register */
237
238#define CMCLKE 0x1000 /* CLK Enable Register (R-Car Gen2) */
239
240static inline u32 sh_cmt_read_cmstr(struct sh_cmt_channel *ch)
241{
242 if (ch->iostart)
243 return ch->cmt->info->read_control(ch->iostart, 0);
244 else
245 return ch->cmt->info->read_control(ch->cmt->mapbase, 0);
246}
247
248static inline void sh_cmt_write_cmstr(struct sh_cmt_channel *ch, u32 value)
249{
250 if (ch->iostart)
251 ch->cmt->info->write_control(ch->iostart, 0, value);
252 else
253 ch->cmt->info->write_control(ch->cmt->mapbase, 0, value);
254}
255
256static inline u32 sh_cmt_read_cmcsr(struct sh_cmt_channel *ch)
257{
258 return ch->cmt->info->read_control(ch->ioctrl, CMCSR);
259}
260
261static inline void sh_cmt_write_cmcsr(struct sh_cmt_channel *ch, u32 value)
262{
263 ch->cmt->info->write_control(ch->ioctrl, CMCSR, value);
264}
265
266static inline u32 sh_cmt_read_cmcnt(struct sh_cmt_channel *ch)
267{
268 return ch->cmt->info->read_count(ch->ioctrl, CMCNT);
269}
270
271static inline void sh_cmt_write_cmcnt(struct sh_cmt_channel *ch, u32 value)
272{
273 ch->cmt->info->write_count(ch->ioctrl, CMCNT, value);
274}
275
276static inline void sh_cmt_write_cmcor(struct sh_cmt_channel *ch, u32 value)
277{
278 ch->cmt->info->write_count(ch->ioctrl, CMCOR, value);
279}
280
281static u32 sh_cmt_get_counter(struct sh_cmt_channel *ch, u32 *has_wrapped)
282{
283 u32 v1, v2, v3;
284 u32 o1, o2;
285
286 o1 = sh_cmt_read_cmcsr(ch) & ch->cmt->info->overflow_bit;
287
288 /* Make sure the timer value is stable. Stolen from acpi_pm.c */
289 do {
290 o2 = o1;
291 v1 = sh_cmt_read_cmcnt(ch);
292 v2 = sh_cmt_read_cmcnt(ch);
293 v3 = sh_cmt_read_cmcnt(ch);
294 o1 = sh_cmt_read_cmcsr(ch) & ch->cmt->info->overflow_bit;
295 } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
296 || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
297
298 *has_wrapped = o1;
299 return v2;
300}
301
302static void sh_cmt_start_stop_ch(struct sh_cmt_channel *ch, int start)
303{
304 unsigned long flags;
305 u32 value;
306
307 /* start stop register shared by multiple timer channels */
308 raw_spin_lock_irqsave(&ch->cmt->lock, flags);
309 value = sh_cmt_read_cmstr(ch);
310
311 if (start)
312 value |= 1 << ch->timer_bit;
313 else
314 value &= ~(1 << ch->timer_bit);
315
316 sh_cmt_write_cmstr(ch, value);
317 raw_spin_unlock_irqrestore(&ch->cmt->lock, flags);
318}
319
320static int sh_cmt_enable(struct sh_cmt_channel *ch)
321{
322 int k, ret;
323
324 dev_pm_syscore_device(&ch->cmt->pdev->dev, true);
325
326 /* enable clock */
327 ret = clk_enable(ch->cmt->clk);
328 if (ret) {
329 dev_err(&ch->cmt->pdev->dev, "ch%u: cannot enable clock\n",
330 ch->index);
331 goto err0;
332 }
333
334 /* make sure channel is disabled */
335 sh_cmt_start_stop_ch(ch, 0);
336
337 /* configure channel, periodic mode and maximum timeout */
338 if (ch->cmt->info->width == 16) {
339 sh_cmt_write_cmcsr(ch, SH_CMT16_CMCSR_CMIE |
340 SH_CMT16_CMCSR_CKS512);
341 } else {
342 u32 cmtout = ch->cmt->info->model <= SH_CMT_48BIT ?
343 SH_CMT32_CMCSR_CMTOUT_IE : 0;
344 sh_cmt_write_cmcsr(ch, cmtout | SH_CMT32_CMCSR_CMM |
345 SH_CMT32_CMCSR_CMR_IRQ |
346 SH_CMT32_CMCSR_CKS_RCLK8);
347 }
348
349 sh_cmt_write_cmcor(ch, 0xffffffff);
350 sh_cmt_write_cmcnt(ch, 0);
351
352 /*
353 * According to the sh73a0 user's manual, as CMCNT can be operated
354 * only by the RCLK (Pseudo 32 kHz), there's one restriction on
355 * modifying CMCNT register; two RCLK cycles are necessary before
356 * this register is either read or any modification of the value
357 * it holds is reflected in the LSI's actual operation.
358 *
359 * While at it, we're supposed to clear out the CMCNT as of this
360 * moment, so make sure it's processed properly here. This will
361 * take RCLKx2 at maximum.
362 */
363 for (k = 0; k < 100; k++) {
364 if (!sh_cmt_read_cmcnt(ch))
365 break;
366 udelay(1);
367 }
368
369 if (sh_cmt_read_cmcnt(ch)) {
370 dev_err(&ch->cmt->pdev->dev, "ch%u: cannot clear CMCNT\n",
371 ch->index);
372 ret = -ETIMEDOUT;
373 goto err1;
374 }
375
376 /* enable channel */
377 sh_cmt_start_stop_ch(ch, 1);
378 return 0;
379 err1:
380 /* stop clock */
381 clk_disable(ch->cmt->clk);
382
383 err0:
384 return ret;
385}
386
387static void sh_cmt_disable(struct sh_cmt_channel *ch)
388{
389 /* disable channel */
390 sh_cmt_start_stop_ch(ch, 0);
391
392 /* disable interrupts in CMT block */
393 sh_cmt_write_cmcsr(ch, 0);
394
395 /* stop clock */
396 clk_disable(ch->cmt->clk);
397
398 dev_pm_syscore_device(&ch->cmt->pdev->dev, false);
399}
400
401/* private flags */
402#define FLAG_CLOCKEVENT (1 << 0)
403#define FLAG_CLOCKSOURCE (1 << 1)
404#define FLAG_REPROGRAM (1 << 2)
405#define FLAG_SKIPEVENT (1 << 3)
406#define FLAG_IRQCONTEXT (1 << 4)
407
408static void sh_cmt_clock_event_program_verify(struct sh_cmt_channel *ch,
409 int absolute)
410{
411 u32 value = ch->next_match_value;
412 u32 new_match;
413 u32 delay = 0;
414 u32 now = 0;
415 u32 has_wrapped;
416
417 now = sh_cmt_get_counter(ch, &has_wrapped);
418 ch->flags |= FLAG_REPROGRAM; /* force reprogram */
419
420 if (has_wrapped) {
421 /* we're competing with the interrupt handler.
422 * -> let the interrupt handler reprogram the timer.
423 * -> interrupt number two handles the event.
424 */
425 ch->flags |= FLAG_SKIPEVENT;
426 return;
427 }
428
429 if (absolute)
430 now = 0;
431
432 do {
433 /* reprogram the timer hardware,
434 * but don't save the new match value yet.
435 */
436 new_match = now + value + delay;
437 if (new_match > ch->max_match_value)
438 new_match = ch->max_match_value;
439
440 sh_cmt_write_cmcor(ch, new_match);
441
442 now = sh_cmt_get_counter(ch, &has_wrapped);
443 if (has_wrapped && (new_match > ch->match_value)) {
444 /* we are changing to a greater match value,
445 * so this wrap must be caused by the counter
446 * matching the old value.
447 * -> first interrupt reprograms the timer.
448 * -> interrupt number two handles the event.
449 */
450 ch->flags |= FLAG_SKIPEVENT;
451 break;
452 }
453
454 if (has_wrapped) {
455 /* we are changing to a smaller match value,
456 * so the wrap must be caused by the counter
457 * matching the new value.
458 * -> save programmed match value.
459 * -> let isr handle the event.
460 */
461 ch->match_value = new_match;
462 break;
463 }
464
465 /* be safe: verify hardware settings */
466 if (now < new_match) {
467 /* timer value is below match value, all good.
468 * this makes sure we won't miss any match events.
469 * -> save programmed match value.
470 * -> let isr handle the event.
471 */
472 ch->match_value = new_match;
473 break;
474 }
475
476 /* the counter has reached a value greater
477 * than our new match value. and since the
478 * has_wrapped flag isn't set we must have
479 * programmed a too close event.
480 * -> increase delay and retry.
481 */
482 if (delay)
483 delay <<= 1;
484 else
485 delay = 1;
486
487 if (!delay)
488 dev_warn(&ch->cmt->pdev->dev, "ch%u: too long delay\n",
489 ch->index);
490
491 } while (delay);
492}
493
494static void __sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta)
495{
496 if (delta > ch->max_match_value)
497 dev_warn(&ch->cmt->pdev->dev, "ch%u: delta out of range\n",
498 ch->index);
499
500 ch->next_match_value = delta;
501 sh_cmt_clock_event_program_verify(ch, 0);
502}
503
504static void sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta)
505{
506 unsigned long flags;
507
508 raw_spin_lock_irqsave(&ch->lock, flags);
509 __sh_cmt_set_next(ch, delta);
510 raw_spin_unlock_irqrestore(&ch->lock, flags);
511}
512
513static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
514{
515 struct sh_cmt_channel *ch = dev_id;
516
517 /* clear flags */
518 sh_cmt_write_cmcsr(ch, sh_cmt_read_cmcsr(ch) &
519 ch->cmt->info->clear_bits);
520
521 /* update clock source counter to begin with if enabled
522 * the wrap flag should be cleared by the timer specific
523 * isr before we end up here.
524 */
525 if (ch->flags & FLAG_CLOCKSOURCE)
526 ch->total_cycles += ch->match_value + 1;
527
528 if (!(ch->flags & FLAG_REPROGRAM))
529 ch->next_match_value = ch->max_match_value;
530
531 ch->flags |= FLAG_IRQCONTEXT;
532
533 if (ch->flags & FLAG_CLOCKEVENT) {
534 if (!(ch->flags & FLAG_SKIPEVENT)) {
535 if (clockevent_state_oneshot(&ch->ced)) {
536 ch->next_match_value = ch->max_match_value;
537 ch->flags |= FLAG_REPROGRAM;
538 }
539
540 ch->ced.event_handler(&ch->ced);
541 }
542 }
543
544 ch->flags &= ~FLAG_SKIPEVENT;
545
546 if (ch->flags & FLAG_REPROGRAM) {
547 ch->flags &= ~FLAG_REPROGRAM;
548 sh_cmt_clock_event_program_verify(ch, 1);
549
550 if (ch->flags & FLAG_CLOCKEVENT)
551 if ((clockevent_state_shutdown(&ch->ced))
552 || (ch->match_value == ch->next_match_value))
553 ch->flags &= ~FLAG_REPROGRAM;
554 }
555
556 ch->flags &= ~FLAG_IRQCONTEXT;
557
558 return IRQ_HANDLED;
559}
560
561static int sh_cmt_start(struct sh_cmt_channel *ch, unsigned long flag)
562{
563 int ret = 0;
564 unsigned long flags;
565
566 if (flag & FLAG_CLOCKSOURCE)
567 pm_runtime_get_sync(&ch->cmt->pdev->dev);
568
569 raw_spin_lock_irqsave(&ch->lock, flags);
570
571 if (!(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE))) {
572 if (flag & FLAG_CLOCKEVENT)
573 pm_runtime_get_sync(&ch->cmt->pdev->dev);
574 ret = sh_cmt_enable(ch);
575 }
576
577 if (ret)
578 goto out;
579 ch->flags |= flag;
580
581 /* setup timeout if no clockevent */
582 if (ch->cmt->num_channels == 1 &&
583 flag == FLAG_CLOCKSOURCE && (!(ch->flags & FLAG_CLOCKEVENT)))
584 __sh_cmt_set_next(ch, ch->max_match_value);
585 out:
586 raw_spin_unlock_irqrestore(&ch->lock, flags);
587
588 return ret;
589}
590
591static void sh_cmt_stop(struct sh_cmt_channel *ch, unsigned long flag)
592{
593 unsigned long flags;
594 unsigned long f;
595
596 raw_spin_lock_irqsave(&ch->lock, flags);
597
598 f = ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
599 ch->flags &= ~flag;
600
601 if (f && !(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE))) {
602 sh_cmt_disable(ch);
603 if (flag & FLAG_CLOCKEVENT)
604 pm_runtime_put(&ch->cmt->pdev->dev);
605 }
606
607 /* adjust the timeout to maximum if only clocksource left */
608 if ((flag == FLAG_CLOCKEVENT) && (ch->flags & FLAG_CLOCKSOURCE))
609 __sh_cmt_set_next(ch, ch->max_match_value);
610
611 raw_spin_unlock_irqrestore(&ch->lock, flags);
612
613 if (flag & FLAG_CLOCKSOURCE)
614 pm_runtime_put(&ch->cmt->pdev->dev);
615}
616
617static struct sh_cmt_channel *cs_to_sh_cmt(struct clocksource *cs)
618{
619 return container_of(cs, struct sh_cmt_channel, cs);
620}
621
622static u64 sh_cmt_clocksource_read(struct clocksource *cs)
623{
624 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
625 u32 has_wrapped;
626
627 if (ch->cmt->num_channels == 1) {
628 unsigned long flags;
629 u64 value;
630 u32 raw;
631
632 raw_spin_lock_irqsave(&ch->lock, flags);
633 value = ch->total_cycles;
634 raw = sh_cmt_get_counter(ch, &has_wrapped);
635
636 if (unlikely(has_wrapped))
637 raw += ch->match_value + 1;
638 raw_spin_unlock_irqrestore(&ch->lock, flags);
639
640 return value + raw;
641 }
642
643 return sh_cmt_get_counter(ch, &has_wrapped);
644}
645
646static int sh_cmt_clocksource_enable(struct clocksource *cs)
647{
648 int ret;
649 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
650
651 WARN_ON(ch->cs_enabled);
652
653 ch->total_cycles = 0;
654
655 ret = sh_cmt_start(ch, FLAG_CLOCKSOURCE);
656 if (!ret)
657 ch->cs_enabled = true;
658
659 return ret;
660}
661
662static void sh_cmt_clocksource_disable(struct clocksource *cs)
663{
664 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
665
666 WARN_ON(!ch->cs_enabled);
667
668 sh_cmt_stop(ch, FLAG_CLOCKSOURCE);
669 ch->cs_enabled = false;
670}
671
672static void sh_cmt_clocksource_suspend(struct clocksource *cs)
673{
674 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
675
676 if (!ch->cs_enabled)
677 return;
678
679 sh_cmt_stop(ch, FLAG_CLOCKSOURCE);
680 dev_pm_genpd_suspend(&ch->cmt->pdev->dev);
681}
682
683static void sh_cmt_clocksource_resume(struct clocksource *cs)
684{
685 struct sh_cmt_channel *ch = cs_to_sh_cmt(cs);
686
687 if (!ch->cs_enabled)
688 return;
689
690 dev_pm_genpd_resume(&ch->cmt->pdev->dev);
691 sh_cmt_start(ch, FLAG_CLOCKSOURCE);
692}
693
694static int sh_cmt_register_clocksource(struct sh_cmt_channel *ch,
695 const char *name)
696{
697 struct clocksource *cs = &ch->cs;
698
699 cs->name = name;
700 cs->rating = 125;
701 cs->read = sh_cmt_clocksource_read;
702 cs->enable = sh_cmt_clocksource_enable;
703 cs->disable = sh_cmt_clocksource_disable;
704 cs->suspend = sh_cmt_clocksource_suspend;
705 cs->resume = sh_cmt_clocksource_resume;
706 cs->mask = CLOCKSOURCE_MASK(ch->cmt->info->width);
707 cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
708
709 dev_info(&ch->cmt->pdev->dev, "ch%u: used as clock source\n",
710 ch->index);
711
712 clocksource_register_hz(cs, ch->cmt->rate);
713 return 0;
714}
715
716static struct sh_cmt_channel *ced_to_sh_cmt(struct clock_event_device *ced)
717{
718 return container_of(ced, struct sh_cmt_channel, ced);
719}
720
721static void sh_cmt_clock_event_start(struct sh_cmt_channel *ch, int periodic)
722{
723 sh_cmt_start(ch, FLAG_CLOCKEVENT);
724
725 if (periodic)
726 sh_cmt_set_next(ch, ((ch->cmt->rate + HZ/2) / HZ) - 1);
727 else
728 sh_cmt_set_next(ch, ch->max_match_value);
729}
730
731static int sh_cmt_clock_event_shutdown(struct clock_event_device *ced)
732{
733 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
734
735 sh_cmt_stop(ch, FLAG_CLOCKEVENT);
736 return 0;
737}
738
739static int sh_cmt_clock_event_set_state(struct clock_event_device *ced,
740 int periodic)
741{
742 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
743
744 /* deal with old setting first */
745 if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
746 sh_cmt_stop(ch, FLAG_CLOCKEVENT);
747
748 dev_info(&ch->cmt->pdev->dev, "ch%u: used for %s clock events\n",
749 ch->index, periodic ? "periodic" : "oneshot");
750 sh_cmt_clock_event_start(ch, periodic);
751 return 0;
752}
753
754static int sh_cmt_clock_event_set_oneshot(struct clock_event_device *ced)
755{
756 return sh_cmt_clock_event_set_state(ced, 0);
757}
758
759static int sh_cmt_clock_event_set_periodic(struct clock_event_device *ced)
760{
761 return sh_cmt_clock_event_set_state(ced, 1);
762}
763
764static int sh_cmt_clock_event_next(unsigned long delta,
765 struct clock_event_device *ced)
766{
767 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
768
769 BUG_ON(!clockevent_state_oneshot(ced));
770 if (likely(ch->flags & FLAG_IRQCONTEXT))
771 ch->next_match_value = delta - 1;
772 else
773 sh_cmt_set_next(ch, delta - 1);
774
775 return 0;
776}
777
778static void sh_cmt_clock_event_suspend(struct clock_event_device *ced)
779{
780 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
781
782 dev_pm_genpd_suspend(&ch->cmt->pdev->dev);
783 clk_unprepare(ch->cmt->clk);
784}
785
786static void sh_cmt_clock_event_resume(struct clock_event_device *ced)
787{
788 struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
789
790 clk_prepare(ch->cmt->clk);
791 dev_pm_genpd_resume(&ch->cmt->pdev->dev);
792}
793
794static int sh_cmt_register_clockevent(struct sh_cmt_channel *ch,
795 const char *name)
796{
797 struct clock_event_device *ced = &ch->ced;
798 int irq;
799 int ret;
800
801 irq = platform_get_irq(ch->cmt->pdev, ch->index);
802 if (irq < 0)
803 return irq;
804
805 ret = request_irq(irq, sh_cmt_interrupt,
806 IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
807 dev_name(&ch->cmt->pdev->dev), ch);
808 if (ret) {
809 dev_err(&ch->cmt->pdev->dev, "ch%u: failed to request irq %d\n",
810 ch->index, irq);
811 return ret;
812 }
813
814 ced->name = name;
815 ced->features = CLOCK_EVT_FEAT_PERIODIC;
816 ced->features |= CLOCK_EVT_FEAT_ONESHOT;
817 ced->rating = 125;
818 ced->cpumask = cpu_possible_mask;
819 ced->set_next_event = sh_cmt_clock_event_next;
820 ced->set_state_shutdown = sh_cmt_clock_event_shutdown;
821 ced->set_state_periodic = sh_cmt_clock_event_set_periodic;
822 ced->set_state_oneshot = sh_cmt_clock_event_set_oneshot;
823 ced->suspend = sh_cmt_clock_event_suspend;
824 ced->resume = sh_cmt_clock_event_resume;
825
826 /* TODO: calculate good shift from rate and counter bit width */
827 ced->shift = 32;
828 ced->mult = div_sc(ch->cmt->rate, NSEC_PER_SEC, ced->shift);
829 ced->max_delta_ns = clockevent_delta2ns(ch->max_match_value, ced);
830 ced->max_delta_ticks = ch->max_match_value;
831 ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
832 ced->min_delta_ticks = 0x1f;
833
834 dev_info(&ch->cmt->pdev->dev, "ch%u: used for clock events\n",
835 ch->index);
836 clockevents_register_device(ced);
837
838 return 0;
839}
840
841static int sh_cmt_register(struct sh_cmt_channel *ch, const char *name,
842 bool clockevent, bool clocksource)
843{
844 int ret;
845
846 if (clockevent) {
847 ch->cmt->has_clockevent = true;
848 ret = sh_cmt_register_clockevent(ch, name);
849 if (ret < 0)
850 return ret;
851 }
852
853 if (clocksource) {
854 ch->cmt->has_clocksource = true;
855 sh_cmt_register_clocksource(ch, name);
856 }
857
858 return 0;
859}
860
861static int sh_cmt_setup_channel(struct sh_cmt_channel *ch, unsigned int index,
862 unsigned int hwidx, bool clockevent,
863 bool clocksource, struct sh_cmt_device *cmt)
864{
865 u32 value;
866 int ret;
867
868 /* Skip unused channels. */
869 if (!clockevent && !clocksource)
870 return 0;
871
872 ch->cmt = cmt;
873 ch->index = index;
874 ch->hwidx = hwidx;
875 ch->timer_bit = hwidx;
876
877 /*
878 * Compute the address of the channel control register block. For the
879 * timers with a per-channel start/stop register, compute its address
880 * as well.
881 */
882 switch (cmt->info->model) {
883 case SH_CMT_16BIT:
884 ch->ioctrl = cmt->mapbase + 2 + ch->hwidx * 6;
885 break;
886 case SH_CMT_32BIT:
887 case SH_CMT_48BIT:
888 ch->ioctrl = cmt->mapbase + 0x10 + ch->hwidx * 0x10;
889 break;
890 case SH_CMT0_RCAR_GEN2:
891 case SH_CMT1_RCAR_GEN2:
892 ch->iostart = cmt->mapbase + ch->hwidx * 0x100;
893 ch->ioctrl = ch->iostart + 0x10;
894 ch->timer_bit = 0;
895
896 /* Enable the clock supply to the channel */
897 value = ioread32(cmt->mapbase + CMCLKE);
898 value |= BIT(hwidx);
899 iowrite32(value, cmt->mapbase + CMCLKE);
900 break;
901 }
902
903 if (cmt->info->width == (sizeof(ch->max_match_value) * 8))
904 ch->max_match_value = ~0;
905 else
906 ch->max_match_value = (1 << cmt->info->width) - 1;
907
908 ch->match_value = ch->max_match_value;
909 raw_spin_lock_init(&ch->lock);
910
911 ret = sh_cmt_register(ch, dev_name(&cmt->pdev->dev),
912 clockevent, clocksource);
913 if (ret) {
914 dev_err(&cmt->pdev->dev, "ch%u: registration failed\n",
915 ch->index);
916 return ret;
917 }
918 ch->cs_enabled = false;
919
920 return 0;
921}
922
923static int sh_cmt_map_memory(struct sh_cmt_device *cmt)
924{
925 struct resource *mem;
926
927 mem = platform_get_resource(cmt->pdev, IORESOURCE_MEM, 0);
928 if (!mem) {
929 dev_err(&cmt->pdev->dev, "failed to get I/O memory\n");
930 return -ENXIO;
931 }
932
933 cmt->mapbase = ioremap(mem->start, resource_size(mem));
934 if (cmt->mapbase == NULL) {
935 dev_err(&cmt->pdev->dev, "failed to remap I/O memory\n");
936 return -ENXIO;
937 }
938
939 return 0;
940}
941
942static const struct platform_device_id sh_cmt_id_table[] = {
943 { "sh-cmt-16", (kernel_ulong_t)&sh_cmt_info[SH_CMT_16BIT] },
944 { "sh-cmt-32", (kernel_ulong_t)&sh_cmt_info[SH_CMT_32BIT] },
945 { }
946};
947MODULE_DEVICE_TABLE(platform, sh_cmt_id_table);
948
949static const struct of_device_id sh_cmt_of_table[] __maybe_unused = {
950 {
951 /* deprecated, preserved for backward compatibility */
952 .compatible = "renesas,cmt-48",
953 .data = &sh_cmt_info[SH_CMT_48BIT]
954 },
955 {
956 /* deprecated, preserved for backward compatibility */
957 .compatible = "renesas,cmt-48-gen2",
958 .data = &sh_cmt_info[SH_CMT0_RCAR_GEN2]
959 },
960 {
961 .compatible = "renesas,r8a7740-cmt1",
962 .data = &sh_cmt_info[SH_CMT_48BIT]
963 },
964 {
965 .compatible = "renesas,sh73a0-cmt1",
966 .data = &sh_cmt_info[SH_CMT_48BIT]
967 },
968 {
969 .compatible = "renesas,rcar-gen2-cmt0",
970 .data = &sh_cmt_info[SH_CMT0_RCAR_GEN2]
971 },
972 {
973 .compatible = "renesas,rcar-gen2-cmt1",
974 .data = &sh_cmt_info[SH_CMT1_RCAR_GEN2]
975 },
976 {
977 .compatible = "renesas,rcar-gen3-cmt0",
978 .data = &sh_cmt_info[SH_CMT0_RCAR_GEN2]
979 },
980 {
981 .compatible = "renesas,rcar-gen3-cmt1",
982 .data = &sh_cmt_info[SH_CMT1_RCAR_GEN2]
983 },
984 { }
985};
986MODULE_DEVICE_TABLE(of, sh_cmt_of_table);
987
988static int sh_cmt_setup(struct sh_cmt_device *cmt, struct platform_device *pdev)
989{
990 unsigned int mask;
991 unsigned int i;
992 int ret;
993
994 cmt->pdev = pdev;
995 raw_spin_lock_init(&cmt->lock);
996
997 if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
998 cmt->info = of_device_get_match_data(&pdev->dev);
999 cmt->hw_channels = cmt->info->channels_mask;
1000 } else if (pdev->dev.platform_data) {
1001 struct sh_timer_config *cfg = pdev->dev.platform_data;
1002 const struct platform_device_id *id = pdev->id_entry;
1003
1004 cmt->info = (const struct sh_cmt_info *)id->driver_data;
1005 cmt->hw_channels = cfg->channels_mask;
1006 } else {
1007 dev_err(&cmt->pdev->dev, "missing platform data\n");
1008 return -ENXIO;
1009 }
1010
1011 /* Get hold of clock. */
1012 cmt->clk = clk_get(&cmt->pdev->dev, "fck");
1013 if (IS_ERR(cmt->clk)) {
1014 dev_err(&cmt->pdev->dev, "cannot get clock\n");
1015 return PTR_ERR(cmt->clk);
1016 }
1017
1018 ret = clk_prepare(cmt->clk);
1019 if (ret < 0)
1020 goto err_clk_put;
1021
1022 /* Determine clock rate. */
1023 ret = clk_enable(cmt->clk);
1024 if (ret < 0)
1025 goto err_clk_unprepare;
1026
1027 if (cmt->info->width == 16)
1028 cmt->rate = clk_get_rate(cmt->clk) / 512;
1029 else
1030 cmt->rate = clk_get_rate(cmt->clk) / 8;
1031
1032 /* Map the memory resource(s). */
1033 ret = sh_cmt_map_memory(cmt);
1034 if (ret < 0)
1035 goto err_clk_disable;
1036
1037 /* Allocate and setup the channels. */
1038 cmt->num_channels = hweight8(cmt->hw_channels);
1039 cmt->channels = kcalloc(cmt->num_channels, sizeof(*cmt->channels),
1040 GFP_KERNEL);
1041 if (cmt->channels == NULL) {
1042 ret = -ENOMEM;
1043 goto err_unmap;
1044 }
1045
1046 /*
1047 * Use the first channel as a clock event device and the second channel
1048 * as a clock source. If only one channel is available use it for both.
1049 */
1050 for (i = 0, mask = cmt->hw_channels; i < cmt->num_channels; ++i) {
1051 unsigned int hwidx = ffs(mask) - 1;
1052 bool clocksource = i == 1 || cmt->num_channels == 1;
1053 bool clockevent = i == 0;
1054
1055 ret = sh_cmt_setup_channel(&cmt->channels[i], i, hwidx,
1056 clockevent, clocksource, cmt);
1057 if (ret < 0)
1058 goto err_unmap;
1059
1060 mask &= ~(1 << hwidx);
1061 }
1062
1063 clk_disable(cmt->clk);
1064
1065 platform_set_drvdata(pdev, cmt);
1066
1067 return 0;
1068
1069err_unmap:
1070 kfree(cmt->channels);
1071 iounmap(cmt->mapbase);
1072err_clk_disable:
1073 clk_disable(cmt->clk);
1074err_clk_unprepare:
1075 clk_unprepare(cmt->clk);
1076err_clk_put:
1077 clk_put(cmt->clk);
1078 return ret;
1079}
1080
1081static int sh_cmt_probe(struct platform_device *pdev)
1082{
1083 struct sh_cmt_device *cmt = platform_get_drvdata(pdev);
1084 int ret;
1085
1086 if (!is_sh_early_platform_device(pdev)) {
1087 pm_runtime_set_active(&pdev->dev);
1088 pm_runtime_enable(&pdev->dev);
1089 }
1090
1091 if (cmt) {
1092 dev_info(&pdev->dev, "kept as earlytimer\n");
1093 goto out;
1094 }
1095
1096 cmt = kzalloc(sizeof(*cmt), GFP_KERNEL);
1097 if (cmt == NULL)
1098 return -ENOMEM;
1099
1100 ret = sh_cmt_setup(cmt, pdev);
1101 if (ret) {
1102 kfree(cmt);
1103 pm_runtime_idle(&pdev->dev);
1104 return ret;
1105 }
1106 if (is_sh_early_platform_device(pdev))
1107 return 0;
1108
1109 out:
1110 if (cmt->has_clockevent || cmt->has_clocksource)
1111 pm_runtime_irq_safe(&pdev->dev);
1112 else
1113 pm_runtime_idle(&pdev->dev);
1114
1115 return 0;
1116}
1117
1118static int sh_cmt_remove(struct platform_device *pdev)
1119{
1120 return -EBUSY; /* cannot unregister clockevent and clocksource */
1121}
1122
1123static struct platform_driver sh_cmt_device_driver = {
1124 .probe = sh_cmt_probe,
1125 .remove = sh_cmt_remove,
1126 .driver = {
1127 .name = "sh_cmt",
1128 .of_match_table = of_match_ptr(sh_cmt_of_table),
1129 },
1130 .id_table = sh_cmt_id_table,
1131};
1132
1133static int __init sh_cmt_init(void)
1134{
1135 return platform_driver_register(&sh_cmt_device_driver);
1136}
1137
1138static void __exit sh_cmt_exit(void)
1139{
1140 platform_driver_unregister(&sh_cmt_device_driver);
1141}
1142
1143#ifdef CONFIG_SUPERH
1144sh_early_platform_init("earlytimer", &sh_cmt_device_driver);
1145#endif
1146
1147subsys_initcall(sh_cmt_init);
1148module_exit(sh_cmt_exit);
1149
1150MODULE_AUTHOR("Magnus Damm");
1151MODULE_DESCRIPTION("SuperH CMT Timer Driver");
1152MODULE_LICENSE("GPL v2");