Linux-libre 3.16.85-gnu
[librecmc/linux-libre.git] / drivers / clocksource / sh_tmu.c
1 /*
2  * SuperH Timer Support - TMU
3  *
4  *  Copyright (C) 2009 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
16 #include <linux/clk.h>
17 #include <linux/clockchips.h>
18 #include <linux/clocksource.h>
19 #include <linux/delay.h>
20 #include <linux/err.h>
21 #include <linux/init.h>
22 #include <linux/interrupt.h>
23 #include <linux/io.h>
24 #include <linux/ioport.h>
25 #include <linux/irq.h>
26 #include <linux/module.h>
27 #include <linux/platform_device.h>
28 #include <linux/pm_domain.h>
29 #include <linux/pm_runtime.h>
30 #include <linux/sh_timer.h>
31 #include <linux/slab.h>
32 #include <linux/spinlock.h>
33
34 enum sh_tmu_model {
35         SH_TMU_LEGACY,
36         SH_TMU,
37         SH_TMU_SH3,
38 };
39
40 struct sh_tmu_device;
41
42 struct sh_tmu_channel {
43         struct sh_tmu_device *tmu;
44         unsigned int index;
45
46         void __iomem *base;
47         int irq;
48
49         unsigned long rate;
50         unsigned long periodic;
51         struct clock_event_device ced;
52         struct clocksource cs;
53         bool cs_enabled;
54         unsigned int enable_count;
55 };
56
57 struct sh_tmu_device {
58         struct platform_device *pdev;
59
60         void __iomem *mapbase;
61         struct clk *clk;
62
63         enum sh_tmu_model model;
64
65         struct sh_tmu_channel *channels;
66         unsigned int num_channels;
67
68         bool has_clockevent;
69         bool has_clocksource;
70 };
71
72 static DEFINE_RAW_SPINLOCK(sh_tmu_lock);
73
74 #define TSTR -1 /* shared register */
75 #define TCOR  0 /* channel register */
76 #define TCNT 1 /* channel register */
77 #define TCR 2 /* channel register */
78
79 #define TCR_UNF                 (1 << 8)
80 #define TCR_UNIE                (1 << 5)
81 #define TCR_TPSC_CLK4           (0 << 0)
82 #define TCR_TPSC_CLK16          (1 << 0)
83 #define TCR_TPSC_CLK64          (2 << 0)
84 #define TCR_TPSC_CLK256         (3 << 0)
85 #define TCR_TPSC_CLK1024        (4 << 0)
86 #define TCR_TPSC_MASK           (7 << 0)
87
88 static inline unsigned long sh_tmu_read(struct sh_tmu_channel *ch, int reg_nr)
89 {
90         unsigned long offs;
91
92         if (reg_nr == TSTR) {
93                 switch (ch->tmu->model) {
94                 case SH_TMU_LEGACY:
95                         return ioread8(ch->tmu->mapbase);
96                 case SH_TMU_SH3:
97                         return ioread8(ch->tmu->mapbase + 2);
98                 case SH_TMU:
99                         return ioread8(ch->tmu->mapbase + 4);
100                 }
101         }
102
103         offs = reg_nr << 2;
104
105         if (reg_nr == TCR)
106                 return ioread16(ch->base + offs);
107         else
108                 return ioread32(ch->base + offs);
109 }
110
111 static inline void sh_tmu_write(struct sh_tmu_channel *ch, int reg_nr,
112                                 unsigned long value)
113 {
114         unsigned long offs;
115
116         if (reg_nr == TSTR) {
117                 switch (ch->tmu->model) {
118                 case SH_TMU_LEGACY:
119                         return iowrite8(value, ch->tmu->mapbase);
120                 case SH_TMU_SH3:
121                         return iowrite8(value, ch->tmu->mapbase + 2);
122                 case SH_TMU:
123                         return iowrite8(value, ch->tmu->mapbase + 4);
124                 }
125         }
126
127         offs = reg_nr << 2;
128
129         if (reg_nr == TCR)
130                 iowrite16(value, ch->base + offs);
131         else
132                 iowrite32(value, ch->base + offs);
133 }
134
135 static void sh_tmu_start_stop_ch(struct sh_tmu_channel *ch, int start)
136 {
137         unsigned long flags, value;
138
139         /* start stop register shared by multiple timer channels */
140         raw_spin_lock_irqsave(&sh_tmu_lock, flags);
141         value = sh_tmu_read(ch, TSTR);
142
143         if (start)
144                 value |= 1 << ch->index;
145         else
146                 value &= ~(1 << ch->index);
147
148         sh_tmu_write(ch, TSTR, value);
149         raw_spin_unlock_irqrestore(&sh_tmu_lock, flags);
150 }
151
152 static int __sh_tmu_enable(struct sh_tmu_channel *ch)
153 {
154         int ret;
155
156         /* enable clock */
157         ret = clk_enable(ch->tmu->clk);
158         if (ret) {
159                 dev_err(&ch->tmu->pdev->dev, "ch%u: cannot enable clock\n",
160                         ch->index);
161                 return ret;
162         }
163
164         /* make sure channel is disabled */
165         sh_tmu_start_stop_ch(ch, 0);
166
167         /* maximum timeout */
168         sh_tmu_write(ch, TCOR, 0xffffffff);
169         sh_tmu_write(ch, TCNT, 0xffffffff);
170
171         /* configure channel to parent clock / 4, irq off */
172         ch->rate = clk_get_rate(ch->tmu->clk) / 4;
173         sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
174
175         /* enable channel */
176         sh_tmu_start_stop_ch(ch, 1);
177
178         return 0;
179 }
180
181 static int sh_tmu_enable(struct sh_tmu_channel *ch)
182 {
183         if (ch->enable_count++ > 0)
184                 return 0;
185
186         pm_runtime_get_sync(&ch->tmu->pdev->dev);
187         dev_pm_syscore_device(&ch->tmu->pdev->dev, true);
188
189         return __sh_tmu_enable(ch);
190 }
191
192 static void __sh_tmu_disable(struct sh_tmu_channel *ch)
193 {
194         /* disable channel */
195         sh_tmu_start_stop_ch(ch, 0);
196
197         /* disable interrupts in TMU block */
198         sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
199
200         /* stop clock */
201         clk_disable(ch->tmu->clk);
202 }
203
204 static void sh_tmu_disable(struct sh_tmu_channel *ch)
205 {
206         if (WARN_ON(ch->enable_count == 0))
207                 return;
208
209         if (--ch->enable_count > 0)
210                 return;
211
212         __sh_tmu_disable(ch);
213
214         dev_pm_syscore_device(&ch->tmu->pdev->dev, false);
215         pm_runtime_put(&ch->tmu->pdev->dev);
216 }
217
218 static void sh_tmu_set_next(struct sh_tmu_channel *ch, unsigned long delta,
219                             int periodic)
220 {
221         /* stop timer */
222         sh_tmu_start_stop_ch(ch, 0);
223
224         /* acknowledge interrupt */
225         sh_tmu_read(ch, TCR);
226
227         /* enable interrupt */
228         sh_tmu_write(ch, TCR, TCR_UNIE | TCR_TPSC_CLK4);
229
230         /* reload delta value in case of periodic timer */
231         if (periodic)
232                 sh_tmu_write(ch, TCOR, delta);
233         else
234                 sh_tmu_write(ch, TCOR, 0xffffffff);
235
236         sh_tmu_write(ch, TCNT, delta);
237
238         /* start timer */
239         sh_tmu_start_stop_ch(ch, 1);
240 }
241
242 static irqreturn_t sh_tmu_interrupt(int irq, void *dev_id)
243 {
244         struct sh_tmu_channel *ch = dev_id;
245
246         /* disable or acknowledge interrupt */
247         if (ch->ced.mode == CLOCK_EVT_MODE_ONESHOT)
248                 sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
249         else
250                 sh_tmu_write(ch, TCR, TCR_UNIE | TCR_TPSC_CLK4);
251
252         /* notify clockevent layer */
253         ch->ced.event_handler(&ch->ced);
254         return IRQ_HANDLED;
255 }
256
257 static struct sh_tmu_channel *cs_to_sh_tmu(struct clocksource *cs)
258 {
259         return container_of(cs, struct sh_tmu_channel, cs);
260 }
261
262 static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
263 {
264         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
265
266         return sh_tmu_read(ch, TCNT) ^ 0xffffffff;
267 }
268
269 static int sh_tmu_clocksource_enable(struct clocksource *cs)
270 {
271         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
272         int ret;
273
274         if (WARN_ON(ch->cs_enabled))
275                 return 0;
276
277         ret = sh_tmu_enable(ch);
278         if (!ret) {
279                 __clocksource_updatefreq_hz(cs, ch->rate);
280                 ch->cs_enabled = true;
281         }
282
283         return ret;
284 }
285
286 static void sh_tmu_clocksource_disable(struct clocksource *cs)
287 {
288         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
289
290         if (WARN_ON(!ch->cs_enabled))
291                 return;
292
293         sh_tmu_disable(ch);
294         ch->cs_enabled = false;
295 }
296
297 static void sh_tmu_clocksource_suspend(struct clocksource *cs)
298 {
299         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
300
301         if (!ch->cs_enabled)
302                 return;
303
304         if (--ch->enable_count == 0) {
305                 __sh_tmu_disable(ch);
306                 pm_genpd_syscore_poweroff(&ch->tmu->pdev->dev);
307         }
308 }
309
310 static void sh_tmu_clocksource_resume(struct clocksource *cs)
311 {
312         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
313
314         if (!ch->cs_enabled)
315                 return;
316
317         if (ch->enable_count++ == 0) {
318                 pm_genpd_syscore_poweron(&ch->tmu->pdev->dev);
319                 __sh_tmu_enable(ch);
320         }
321 }
322
323 static int sh_tmu_register_clocksource(struct sh_tmu_channel *ch,
324                                        const char *name)
325 {
326         struct clocksource *cs = &ch->cs;
327
328         cs->name = name;
329         cs->rating = 200;
330         cs->read = sh_tmu_clocksource_read;
331         cs->enable = sh_tmu_clocksource_enable;
332         cs->disable = sh_tmu_clocksource_disable;
333         cs->suspend = sh_tmu_clocksource_suspend;
334         cs->resume = sh_tmu_clocksource_resume;
335         cs->mask = CLOCKSOURCE_MASK(32);
336         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
337
338         dev_info(&ch->tmu->pdev->dev, "ch%u: used as clock source\n",
339                  ch->index);
340
341         /* Register with dummy 1 Hz value, gets updated in ->enable() */
342         clocksource_register_hz(cs, 1);
343         return 0;
344 }
345
346 static struct sh_tmu_channel *ced_to_sh_tmu(struct clock_event_device *ced)
347 {
348         return container_of(ced, struct sh_tmu_channel, ced);
349 }
350
351 static void sh_tmu_clock_event_start(struct sh_tmu_channel *ch, int periodic)
352 {
353         struct clock_event_device *ced = &ch->ced;
354
355         sh_tmu_enable(ch);
356
357         clockevents_config(ced, ch->rate);
358
359         if (periodic) {
360                 ch->periodic = (ch->rate + HZ/2) / HZ;
361                 sh_tmu_set_next(ch, ch->periodic, 1);
362         }
363 }
364
365 static void sh_tmu_clock_event_mode(enum clock_event_mode mode,
366                                     struct clock_event_device *ced)
367 {
368         struct sh_tmu_channel *ch = ced_to_sh_tmu(ced);
369         int disabled = 0;
370
371         /* deal with old setting first */
372         switch (ced->mode) {
373         case CLOCK_EVT_MODE_PERIODIC:
374         case CLOCK_EVT_MODE_ONESHOT:
375                 sh_tmu_disable(ch);
376                 disabled = 1;
377                 break;
378         default:
379                 break;
380         }
381
382         switch (mode) {
383         case CLOCK_EVT_MODE_PERIODIC:
384                 dev_info(&ch->tmu->pdev->dev,
385                          "ch%u: used for periodic clock events\n", ch->index);
386                 sh_tmu_clock_event_start(ch, 1);
387                 break;
388         case CLOCK_EVT_MODE_ONESHOT:
389                 dev_info(&ch->tmu->pdev->dev,
390                          "ch%u: used for oneshot clock events\n", ch->index);
391                 sh_tmu_clock_event_start(ch, 0);
392                 break;
393         case CLOCK_EVT_MODE_UNUSED:
394                 if (!disabled)
395                         sh_tmu_disable(ch);
396                 break;
397         case CLOCK_EVT_MODE_SHUTDOWN:
398         default:
399                 break;
400         }
401 }
402
403 static int sh_tmu_clock_event_next(unsigned long delta,
404                                    struct clock_event_device *ced)
405 {
406         struct sh_tmu_channel *ch = ced_to_sh_tmu(ced);
407
408         BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
409
410         /* program new delta value */
411         sh_tmu_set_next(ch, delta, 0);
412         return 0;
413 }
414
415 static void sh_tmu_clock_event_suspend(struct clock_event_device *ced)
416 {
417         pm_genpd_syscore_poweroff(&ced_to_sh_tmu(ced)->tmu->pdev->dev);
418 }
419
420 static void sh_tmu_clock_event_resume(struct clock_event_device *ced)
421 {
422         pm_genpd_syscore_poweron(&ced_to_sh_tmu(ced)->tmu->pdev->dev);
423 }
424
425 static void sh_tmu_register_clockevent(struct sh_tmu_channel *ch,
426                                        const char *name)
427 {
428         struct clock_event_device *ced = &ch->ced;
429         int ret;
430
431         ced->name = name;
432         ced->features = CLOCK_EVT_FEAT_PERIODIC;
433         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
434         ced->rating = 200;
435         ced->cpumask = cpumask_of(0);
436         ced->set_next_event = sh_tmu_clock_event_next;
437         ced->set_mode = sh_tmu_clock_event_mode;
438         ced->suspend = sh_tmu_clock_event_suspend;
439         ced->resume = sh_tmu_clock_event_resume;
440
441         dev_info(&ch->tmu->pdev->dev, "ch%u: used for clock events\n",
442                  ch->index);
443
444         clockevents_config_and_register(ced, 1, 0x300, 0xffffffff);
445
446         ret = request_irq(ch->irq, sh_tmu_interrupt,
447                           IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
448                           dev_name(&ch->tmu->pdev->dev), ch);
449         if (ret) {
450                 dev_err(&ch->tmu->pdev->dev, "ch%u: failed to request irq %d\n",
451                         ch->index, ch->irq);
452                 return;
453         }
454 }
455
456 static int sh_tmu_register(struct sh_tmu_channel *ch, const char *name,
457                            bool clockevent, bool clocksource)
458 {
459         if (clockevent) {
460                 ch->tmu->has_clockevent = true;
461                 sh_tmu_register_clockevent(ch, name);
462         } else if (clocksource) {
463                 ch->tmu->has_clocksource = true;
464                 sh_tmu_register_clocksource(ch, name);
465         }
466
467         return 0;
468 }
469
470 static int sh_tmu_channel_setup(struct sh_tmu_channel *ch, unsigned int index,
471                                 bool clockevent, bool clocksource,
472                                 struct sh_tmu_device *tmu)
473 {
474         /* Skip unused channels. */
475         if (!clockevent && !clocksource)
476                 return 0;
477
478         ch->tmu = tmu;
479
480         if (tmu->model == SH_TMU_LEGACY) {
481                 struct sh_timer_config *cfg = tmu->pdev->dev.platform_data;
482
483                 /*
484                  * The SH3 variant (SH770x, SH7705, SH7710 and SH7720) maps
485                  * channel registers blocks at base + 2 + 12 * index, while all
486                  * other variants map them at base + 4 + 12 * index. We can
487                  * compute the index by just dividing by 12, the 2 bytes or 4
488                  * bytes offset being hidden by the integer division.
489                  */
490                 ch->index = cfg->channel_offset / 12;
491                 ch->base = tmu->mapbase + cfg->channel_offset;
492         } else {
493                 ch->index = index;
494
495                 if (tmu->model == SH_TMU_SH3)
496                         ch->base = tmu->mapbase + 4 + ch->index * 12;
497                 else
498                         ch->base = tmu->mapbase + 8 + ch->index * 12;
499         }
500
501         ch->irq = platform_get_irq(tmu->pdev, index);
502         if (ch->irq < 0) {
503                 dev_err(&tmu->pdev->dev, "ch%u: failed to get irq\n",
504                         ch->index);
505                 return ch->irq;
506         }
507
508         ch->cs_enabled = false;
509         ch->enable_count = 0;
510
511         return sh_tmu_register(ch, dev_name(&tmu->pdev->dev),
512                                clockevent, clocksource);
513 }
514
515 static int sh_tmu_map_memory(struct sh_tmu_device *tmu)
516 {
517         struct resource *res;
518
519         res = platform_get_resource(tmu->pdev, IORESOURCE_MEM, 0);
520         if (!res) {
521                 dev_err(&tmu->pdev->dev, "failed to get I/O memory\n");
522                 return -ENXIO;
523         }
524
525         tmu->mapbase = ioremap_nocache(res->start, resource_size(res));
526         if (tmu->mapbase == NULL)
527                 return -ENXIO;
528
529         /*
530          * In legacy platform device configuration (with one device per channel)
531          * the resource points to the channel base address.
532          */
533         if (tmu->model == SH_TMU_LEGACY) {
534                 struct sh_timer_config *cfg = tmu->pdev->dev.platform_data;
535                 tmu->mapbase -= cfg->channel_offset;
536         }
537
538         return 0;
539 }
540
541 static void sh_tmu_unmap_memory(struct sh_tmu_device *tmu)
542 {
543         if (tmu->model == SH_TMU_LEGACY) {
544                 struct sh_timer_config *cfg = tmu->pdev->dev.platform_data;
545                 tmu->mapbase += cfg->channel_offset;
546         }
547
548         iounmap(tmu->mapbase);
549 }
550
551 static int sh_tmu_setup(struct sh_tmu_device *tmu, struct platform_device *pdev)
552 {
553         struct sh_timer_config *cfg = pdev->dev.platform_data;
554         const struct platform_device_id *id = pdev->id_entry;
555         unsigned int i;
556         int ret;
557
558         if (!cfg) {
559                 dev_err(&tmu->pdev->dev, "missing platform data\n");
560                 return -ENXIO;
561         }
562
563         tmu->pdev = pdev;
564         tmu->model = id->driver_data;
565
566         /* Get hold of clock. */
567         tmu->clk = clk_get(&tmu->pdev->dev,
568                            tmu->model == SH_TMU_LEGACY ? "tmu_fck" : "fck");
569         if (IS_ERR(tmu->clk)) {
570                 dev_err(&tmu->pdev->dev, "cannot get clock\n");
571                 return PTR_ERR(tmu->clk);
572         }
573
574         ret = clk_prepare(tmu->clk);
575         if (ret < 0)
576                 goto err_clk_put;
577
578         /* Map the memory resource. */
579         ret = sh_tmu_map_memory(tmu);
580         if (ret < 0) {
581                 dev_err(&tmu->pdev->dev, "failed to remap I/O memory\n");
582                 goto err_clk_unprepare;
583         }
584
585         /* Allocate and setup the channels. */
586         if (tmu->model == SH_TMU_LEGACY)
587                 tmu->num_channels = 1;
588         else
589                 tmu->num_channels = hweight8(cfg->channels_mask);
590
591         tmu->channels = kzalloc(sizeof(*tmu->channels) * tmu->num_channels,
592                                 GFP_KERNEL);
593         if (tmu->channels == NULL) {
594                 ret = -ENOMEM;
595                 goto err_unmap;
596         }
597
598         if (tmu->model == SH_TMU_LEGACY) {
599                 ret = sh_tmu_channel_setup(&tmu->channels[0], 0,
600                                            cfg->clockevent_rating != 0,
601                                            cfg->clocksource_rating != 0, tmu);
602                 if (ret < 0)
603                         goto err_unmap;
604         } else {
605                 /*
606                  * Use the first channel as a clock event device and the second
607                  * channel as a clock source.
608                  */
609                 for (i = 0; i < tmu->num_channels; ++i) {
610                         ret = sh_tmu_channel_setup(&tmu->channels[i], i,
611                                                    i == 0, i == 1, tmu);
612                         if (ret < 0)
613                                 goto err_unmap;
614                 }
615         }
616
617         platform_set_drvdata(pdev, tmu);
618
619         return 0;
620
621 err_unmap:
622         kfree(tmu->channels);
623         sh_tmu_unmap_memory(tmu);
624 err_clk_unprepare:
625         clk_unprepare(tmu->clk);
626 err_clk_put:
627         clk_put(tmu->clk);
628         return ret;
629 }
630
631 static int sh_tmu_probe(struct platform_device *pdev)
632 {
633         struct sh_tmu_device *tmu = platform_get_drvdata(pdev);
634         int ret;
635
636         if (!is_early_platform_device(pdev)) {
637                 pm_runtime_set_active(&pdev->dev);
638                 pm_runtime_enable(&pdev->dev);
639         }
640
641         if (tmu) {
642                 dev_info(&pdev->dev, "kept as earlytimer\n");
643                 goto out;
644         }
645
646         tmu = kzalloc(sizeof(*tmu), GFP_KERNEL);
647         if (tmu == NULL)
648                 return -ENOMEM;
649
650         ret = sh_tmu_setup(tmu, pdev);
651         if (ret) {
652                 kfree(tmu);
653                 pm_runtime_idle(&pdev->dev);
654                 return ret;
655         }
656         if (is_early_platform_device(pdev))
657                 return 0;
658
659  out:
660         if (tmu->has_clockevent || tmu->has_clocksource)
661                 pm_runtime_irq_safe(&pdev->dev);
662         else
663                 pm_runtime_idle(&pdev->dev);
664
665         return 0;
666 }
667
668 static int sh_tmu_remove(struct platform_device *pdev)
669 {
670         return -EBUSY; /* cannot unregister clockevent and clocksource */
671 }
672
673 static const struct platform_device_id sh_tmu_id_table[] = {
674         { "sh_tmu", SH_TMU_LEGACY },
675         { "sh-tmu", SH_TMU },
676         { "sh-tmu-sh3", SH_TMU_SH3 },
677         { }
678 };
679 MODULE_DEVICE_TABLE(platform, sh_tmu_id_table);
680
681 static struct platform_driver sh_tmu_device_driver = {
682         .probe          = sh_tmu_probe,
683         .remove         = sh_tmu_remove,
684         .driver         = {
685                 .name   = "sh_tmu",
686         },
687         .id_table       = sh_tmu_id_table,
688 };
689
690 static int __init sh_tmu_init(void)
691 {
692         return platform_driver_register(&sh_tmu_device_driver);
693 }
694
695 static void __exit sh_tmu_exit(void)
696 {
697         platform_driver_unregister(&sh_tmu_device_driver);
698 }
699
700 early_platform_init("earlytimer", &sh_tmu_device_driver);
701 subsys_initcall(sh_tmu_init);
702 module_exit(sh_tmu_exit);
703
704 MODULE_AUTHOR("Magnus Damm");
705 MODULE_DESCRIPTION("SuperH TMU Timer Driver");
706 MODULE_LICENSE("GPL v2");