Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/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/of.h>
 28 #include <linux/platform_device.h>
 29 #include <linux/pm_domain.h>
 30 #include <linux/pm_runtime.h>
 31 #include <linux/sh_timer.h>
 32 #include <linux/slab.h>
 33 #include <linux/spinlock.h>
 34 
 35 enum sh_tmu_model {
 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         raw_spinlock_t lock; /* Protect the shared start/stop register */
 66 
 67         struct sh_tmu_channel *channels;
 68         unsigned int num_channels;
 69 
 70         bool has_clockevent;
 71         bool has_clocksource;
 72 };
 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_SH3:
 95                         return ioread8(ch->tmu->mapbase + 2);
 96                 case SH_TMU:
 97                         return ioread8(ch->tmu->mapbase + 4);
 98                 }
 99         }
100 
101         offs = reg_nr << 2;
102 
103         if (reg_nr == TCR)
104                 return ioread16(ch->base + offs);
105         else
106                 return ioread32(ch->base + offs);
107 }
108 
109 static inline void sh_tmu_write(struct sh_tmu_channel *ch, int reg_nr,
110                                 unsigned long value)
111 {
112         unsigned long offs;
113 
114         if (reg_nr == TSTR) {
115                 switch (ch->tmu->model) {
116                 case SH_TMU_SH3:
117                         return iowrite8(value, ch->tmu->mapbase + 2);
118                 case SH_TMU:
119                         return iowrite8(value, ch->tmu->mapbase + 4);
120                 }
121         }
122 
123         offs = reg_nr << 2;
124 
125         if (reg_nr == TCR)
126                 iowrite16(value, ch->base + offs);
127         else
128                 iowrite32(value, ch->base + offs);
129 }
130 
131 static void sh_tmu_start_stop_ch(struct sh_tmu_channel *ch, int start)
132 {
133         unsigned long flags, value;
134 
135         /* start stop register shared by multiple timer channels */
136         raw_spin_lock_irqsave(&ch->tmu->lock, flags);
137         value = sh_tmu_read(ch, TSTR);
138 
139         if (start)
140                 value |= 1 << ch->index;
141         else
142                 value &= ~(1 << ch->index);
143 
144         sh_tmu_write(ch, TSTR, value);
145         raw_spin_unlock_irqrestore(&ch->tmu->lock, flags);
146 }
147 
148 static int __sh_tmu_enable(struct sh_tmu_channel *ch)
149 {
150         int ret;
151 
152         /* enable clock */
153         ret = clk_enable(ch->tmu->clk);
154         if (ret) {
155                 dev_err(&ch->tmu->pdev->dev, "ch%u: cannot enable clock\n",
156                         ch->index);
157                 return ret;
158         }
159 
160         /* make sure channel is disabled */
161         sh_tmu_start_stop_ch(ch, 0);
162 
163         /* maximum timeout */
164         sh_tmu_write(ch, TCOR, 0xffffffff);
165         sh_tmu_write(ch, TCNT, 0xffffffff);
166 
167         /* configure channel to parent clock / 4, irq off */
168         ch->rate = clk_get_rate(ch->tmu->clk) / 4;
169         sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
170 
171         /* enable channel */
172         sh_tmu_start_stop_ch(ch, 1);
173 
174         return 0;
175 }
176 
177 static int sh_tmu_enable(struct sh_tmu_channel *ch)
178 {
179         if (ch->enable_count++ > 0)
180                 return 0;
181 
182         pm_runtime_get_sync(&ch->tmu->pdev->dev);
183         dev_pm_syscore_device(&ch->tmu->pdev->dev, true);
184 
185         return __sh_tmu_enable(ch);
186 }
187 
188 static void __sh_tmu_disable(struct sh_tmu_channel *ch)
189 {
190         /* disable channel */
191         sh_tmu_start_stop_ch(ch, 0);
192 
193         /* disable interrupts in TMU block */
194         sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
195 
196         /* stop clock */
197         clk_disable(ch->tmu->clk);
198 }
199 
200 static void sh_tmu_disable(struct sh_tmu_channel *ch)
201 {
202         if (WARN_ON(ch->enable_count == 0))
203                 return;
204 
205         if (--ch->enable_count > 0)
206                 return;
207 
208         __sh_tmu_disable(ch);
209 
210         dev_pm_syscore_device(&ch->tmu->pdev->dev, false);
211         pm_runtime_put(&ch->tmu->pdev->dev);
212 }
213 
214 static void sh_tmu_set_next(struct sh_tmu_channel *ch, unsigned long delta,
215                             int periodic)
216 {
217         /* stop timer */
218         sh_tmu_start_stop_ch(ch, 0);
219 
220         /* acknowledge interrupt */
221         sh_tmu_read(ch, TCR);
222 
223         /* enable interrupt */
224         sh_tmu_write(ch, TCR, TCR_UNIE | TCR_TPSC_CLK4);
225 
226         /* reload delta value in case of periodic timer */
227         if (periodic)
228                 sh_tmu_write(ch, TCOR, delta);
229         else
230                 sh_tmu_write(ch, TCOR, 0xffffffff);
231 
232         sh_tmu_write(ch, TCNT, delta);
233 
234         /* start timer */
235         sh_tmu_start_stop_ch(ch, 1);
236 }
237 
238 static irqreturn_t sh_tmu_interrupt(int irq, void *dev_id)
239 {
240         struct sh_tmu_channel *ch = dev_id;
241 
242         /* disable or acknowledge interrupt */
243         if (ch->ced.mode == CLOCK_EVT_MODE_ONESHOT)
244                 sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
245         else
246                 sh_tmu_write(ch, TCR, TCR_UNIE | TCR_TPSC_CLK4);
247 
248         /* notify clockevent layer */
249         ch->ced.event_handler(&ch->ced);
250         return IRQ_HANDLED;
251 }
252 
253 static struct sh_tmu_channel *cs_to_sh_tmu(struct clocksource *cs)
254 {
255         return container_of(cs, struct sh_tmu_channel, cs);
256 }
257 
258 static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
259 {
260         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
261 
262         return sh_tmu_read(ch, TCNT) ^ 0xffffffff;
263 }
264 
265 static int sh_tmu_clocksource_enable(struct clocksource *cs)
266 {
267         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
268         int ret;
269 
270         if (WARN_ON(ch->cs_enabled))
271                 return 0;
272 
273         ret = sh_tmu_enable(ch);
274         if (!ret) {
275                 __clocksource_updatefreq_hz(cs, ch->rate);
276                 ch->cs_enabled = true;
277         }
278 
279         return ret;
280 }
281 
282 static void sh_tmu_clocksource_disable(struct clocksource *cs)
283 {
284         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
285 
286         if (WARN_ON(!ch->cs_enabled))
287                 return;
288 
289         sh_tmu_disable(ch);
290         ch->cs_enabled = false;
291 }
292 
293 static void sh_tmu_clocksource_suspend(struct clocksource *cs)
294 {
295         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
296 
297         if (!ch->cs_enabled)
298                 return;
299 
300         if (--ch->enable_count == 0) {
301                 __sh_tmu_disable(ch);
302                 pm_genpd_syscore_poweroff(&ch->tmu->pdev->dev);
303         }
304 }
305 
306 static void sh_tmu_clocksource_resume(struct clocksource *cs)
307 {
308         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
309 
310         if (!ch->cs_enabled)
311                 return;
312 
313         if (ch->enable_count++ == 0) {
314                 pm_genpd_syscore_poweron(&ch->tmu->pdev->dev);
315                 __sh_tmu_enable(ch);
316         }
317 }
318 
319 static int sh_tmu_register_clocksource(struct sh_tmu_channel *ch,
320                                        const char *name)
321 {
322         struct clocksource *cs = &ch->cs;
323 
324         cs->name = name;
325         cs->rating = 200;
326         cs->read = sh_tmu_clocksource_read;
327         cs->enable = sh_tmu_clocksource_enable;
328         cs->disable = sh_tmu_clocksource_disable;
329         cs->suspend = sh_tmu_clocksource_suspend;
330         cs->resume = sh_tmu_clocksource_resume;
331         cs->mask = CLOCKSOURCE_MASK(32);
332         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
333 
334         dev_info(&ch->tmu->pdev->dev, "ch%u: used as clock source\n",
335                  ch->index);
336 
337         /* Register with dummy 1 Hz value, gets updated in ->enable() */
338         clocksource_register_hz(cs, 1);
339         return 0;
340 }
341 
342 static struct sh_tmu_channel *ced_to_sh_tmu(struct clock_event_device *ced)
343 {
344         return container_of(ced, struct sh_tmu_channel, ced);
345 }
346 
347 static void sh_tmu_clock_event_start(struct sh_tmu_channel *ch, int periodic)
348 {
349         struct clock_event_device *ced = &ch->ced;
350 
351         sh_tmu_enable(ch);
352 
353         clockevents_config(ced, ch->rate);
354 
355         if (periodic) {
356                 ch->periodic = (ch->rate + HZ/2) / HZ;
357                 sh_tmu_set_next(ch, ch->periodic, 1);
358         }
359 }
360 
361 static void sh_tmu_clock_event_mode(enum clock_event_mode mode,
362                                     struct clock_event_device *ced)
363 {
364         struct sh_tmu_channel *ch = ced_to_sh_tmu(ced);
365         int disabled = 0;
366 
367         /* deal with old setting first */
368         switch (ced->mode) {
369         case CLOCK_EVT_MODE_PERIODIC:
370         case CLOCK_EVT_MODE_ONESHOT:
371                 sh_tmu_disable(ch);
372                 disabled = 1;
373                 break;
374         default:
375                 break;
376         }
377 
378         switch (mode) {
379         case CLOCK_EVT_MODE_PERIODIC:
380                 dev_info(&ch->tmu->pdev->dev,
381                          "ch%u: used for periodic clock events\n", ch->index);
382                 sh_tmu_clock_event_start(ch, 1);
383                 break;
384         case CLOCK_EVT_MODE_ONESHOT:
385                 dev_info(&ch->tmu->pdev->dev,
386                          "ch%u: used for oneshot clock events\n", ch->index);
387                 sh_tmu_clock_event_start(ch, 0);
388                 break;
389         case CLOCK_EVT_MODE_UNUSED:
390                 if (!disabled)
391                         sh_tmu_disable(ch);
392                 break;
393         case CLOCK_EVT_MODE_SHUTDOWN:
394         default:
395                 break;
396         }
397 }
398 
399 static int sh_tmu_clock_event_next(unsigned long delta,
400                                    struct clock_event_device *ced)
401 {
402         struct sh_tmu_channel *ch = ced_to_sh_tmu(ced);
403 
404         BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
405 
406         /* program new delta value */
407         sh_tmu_set_next(ch, delta, 0);
408         return 0;
409 }
410 
411 static void sh_tmu_clock_event_suspend(struct clock_event_device *ced)
412 {
413         pm_genpd_syscore_poweroff(&ced_to_sh_tmu(ced)->tmu->pdev->dev);
414 }
415 
416 static void sh_tmu_clock_event_resume(struct clock_event_device *ced)
417 {
418         pm_genpd_syscore_poweron(&ced_to_sh_tmu(ced)->tmu->pdev->dev);
419 }
420 
421 static void sh_tmu_register_clockevent(struct sh_tmu_channel *ch,
422                                        const char *name)
423 {
424         struct clock_event_device *ced = &ch->ced;
425         int ret;
426 
427         ced->name = name;
428         ced->features = CLOCK_EVT_FEAT_PERIODIC;
429         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
430         ced->rating = 200;
431         ced->cpumask = cpumask_of(0);
432         ced->set_next_event = sh_tmu_clock_event_next;
433         ced->set_mode = sh_tmu_clock_event_mode;
434         ced->suspend = sh_tmu_clock_event_suspend;
435         ced->resume = sh_tmu_clock_event_resume;
436 
437         dev_info(&ch->tmu->pdev->dev, "ch%u: used for clock events\n",
438                  ch->index);
439 
440         clockevents_config_and_register(ced, 1, 0x300, 0xffffffff);
441 
442         ret = request_irq(ch->irq, sh_tmu_interrupt,
443                           IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
444                           dev_name(&ch->tmu->pdev->dev), ch);
445         if (ret) {
446                 dev_err(&ch->tmu->pdev->dev, "ch%u: failed to request irq %d\n",
447                         ch->index, ch->irq);
448                 return;
449         }
450 }
451 
452 static int sh_tmu_register(struct sh_tmu_channel *ch, const char *name,
453                            bool clockevent, bool clocksource)
454 {
455         if (clockevent) {
456                 ch->tmu->has_clockevent = true;
457                 sh_tmu_register_clockevent(ch, name);
458         } else if (clocksource) {
459                 ch->tmu->has_clocksource = true;
460                 sh_tmu_register_clocksource(ch, name);
461         }
462 
463         return 0;
464 }
465 
466 static int sh_tmu_channel_setup(struct sh_tmu_channel *ch, unsigned int index,
467                                 bool clockevent, bool clocksource,
468                                 struct sh_tmu_device *tmu)
469 {
470         /* Skip unused channels. */
471         if (!clockevent && !clocksource)
472                 return 0;
473 
474         ch->tmu = tmu;
475         ch->index = index;
476 
477         if (tmu->model == SH_TMU_SH3)
478                 ch->base = tmu->mapbase + 4 + ch->index * 12;
479         else
480                 ch->base = tmu->mapbase + 8 + ch->index * 12;
481 
482         ch->irq = platform_get_irq(tmu->pdev, index);
483         if (ch->irq < 0) {
484                 dev_err(&tmu->pdev->dev, "ch%u: failed to get irq\n",
485                         ch->index);
486                 return ch->irq;
487         }
488 
489         ch->cs_enabled = false;
490         ch->enable_count = 0;
491 
492         return sh_tmu_register(ch, dev_name(&tmu->pdev->dev),
493                                clockevent, clocksource);
494 }
495 
496 static int sh_tmu_map_memory(struct sh_tmu_device *tmu)
497 {
498         struct resource *res;
499 
500         res = platform_get_resource(tmu->pdev, IORESOURCE_MEM, 0);
501         if (!res) {
502                 dev_err(&tmu->pdev->dev, "failed to get I/O memory\n");
503                 return -ENXIO;
504         }
505 
506         tmu->mapbase = ioremap_nocache(res->start, resource_size(res));
507         if (tmu->mapbase == NULL)
508                 return -ENXIO;
509 
510         return 0;
511 }
512 
513 static int sh_tmu_parse_dt(struct sh_tmu_device *tmu)
514 {
515         struct device_node *np = tmu->pdev->dev.of_node;
516 
517         tmu->model = SH_TMU;
518         tmu->num_channels = 3;
519 
520         of_property_read_u32(np, "#renesas,channels", &tmu->num_channels);
521 
522         if (tmu->num_channels != 2 && tmu->num_channels != 3) {
523                 dev_err(&tmu->pdev->dev, "invalid number of channels %u\n",
524                         tmu->num_channels);
525                 return -EINVAL;
526         }
527 
528         return 0;
529 }
530 
531 static int sh_tmu_setup(struct sh_tmu_device *tmu, struct platform_device *pdev)
532 {
533         unsigned int i;
534         int ret;
535 
536         tmu->pdev = pdev;
537 
538         raw_spin_lock_init(&tmu->lock);
539 
540         if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
541                 ret = sh_tmu_parse_dt(tmu);
542                 if (ret < 0)
543                         return ret;
544         } else if (pdev->dev.platform_data) {
545                 const struct platform_device_id *id = pdev->id_entry;
546                 struct sh_timer_config *cfg = pdev->dev.platform_data;
547 
548                 tmu->model = id->driver_data;
549                 tmu->num_channels = hweight8(cfg->channels_mask);
550         } else {
551                 dev_err(&tmu->pdev->dev, "missing platform data\n");
552                 return -ENXIO;
553         }
554 
555         /* Get hold of clock. */
556         tmu->clk = clk_get(&tmu->pdev->dev, "fck");
557         if (IS_ERR(tmu->clk)) {
558                 dev_err(&tmu->pdev->dev, "cannot get clock\n");
559                 return PTR_ERR(tmu->clk);
560         }
561 
562         ret = clk_prepare(tmu->clk);
563         if (ret < 0)
564                 goto err_clk_put;
565 
566         /* Map the memory resource. */
567         ret = sh_tmu_map_memory(tmu);
568         if (ret < 0) {
569                 dev_err(&tmu->pdev->dev, "failed to remap I/O memory\n");
570                 goto err_clk_unprepare;
571         }
572 
573         /* Allocate and setup the channels. */
574         tmu->channels = kzalloc(sizeof(*tmu->channels) * tmu->num_channels,
575                                 GFP_KERNEL);
576         if (tmu->channels == NULL) {
577                 ret = -ENOMEM;
578                 goto err_unmap;
579         }
580 
581         /*
582          * Use the first channel as a clock event device and the second channel
583          * as a clock source.
584          */
585         for (i = 0; i < tmu->num_channels; ++i) {
586                 ret = sh_tmu_channel_setup(&tmu->channels[i], i,
587                                            i == 0, i == 1, tmu);
588                 if (ret < 0)
589                         goto err_unmap;
590         }
591 
592         platform_set_drvdata(pdev, tmu);
593 
594         return 0;
595 
596 err_unmap:
597         kfree(tmu->channels);
598         iounmap(tmu->mapbase);
599 err_clk_unprepare:
600         clk_unprepare(tmu->clk);
601 err_clk_put:
602         clk_put(tmu->clk);
603         return ret;
604 }
605 
606 static int sh_tmu_probe(struct platform_device *pdev)
607 {
608         struct sh_tmu_device *tmu = platform_get_drvdata(pdev);
609         int ret;
610 
611         if (!is_early_platform_device(pdev)) {
612                 pm_runtime_set_active(&pdev->dev);
613                 pm_runtime_enable(&pdev->dev);
614         }
615 
616         if (tmu) {
617                 dev_info(&pdev->dev, "kept as earlytimer\n");
618                 goto out;
619         }
620 
621         tmu = kzalloc(sizeof(*tmu), GFP_KERNEL);
622         if (tmu == NULL)
623                 return -ENOMEM;
624 
625         ret = sh_tmu_setup(tmu, pdev);
626         if (ret) {
627                 kfree(tmu);
628                 pm_runtime_idle(&pdev->dev);
629                 return ret;
630         }
631         if (is_early_platform_device(pdev))
632                 return 0;
633 
634  out:
635         if (tmu->has_clockevent || tmu->has_clocksource)
636                 pm_runtime_irq_safe(&pdev->dev);
637         else
638                 pm_runtime_idle(&pdev->dev);
639 
640         return 0;
641 }
642 
643 static int sh_tmu_remove(struct platform_device *pdev)
644 {
645         return -EBUSY; /* cannot unregister clockevent and clocksource */
646 }
647 
648 static const struct platform_device_id sh_tmu_id_table[] = {
649         { "sh-tmu", SH_TMU },
650         { "sh-tmu-sh3", SH_TMU_SH3 },
651         { }
652 };
653 MODULE_DEVICE_TABLE(platform, sh_tmu_id_table);
654 
655 static const struct of_device_id sh_tmu_of_table[] __maybe_unused = {
656         { .compatible = "renesas,tmu" },
657         { }
658 };
659 MODULE_DEVICE_TABLE(of, sh_tmu_of_table);
660 
661 static struct platform_driver sh_tmu_device_driver = {
662         .probe          = sh_tmu_probe,
663         .remove         = sh_tmu_remove,
664         .driver         = {
665                 .name   = "sh_tmu",
666                 .of_match_table = of_match_ptr(sh_tmu_of_table),
667         },
668         .id_table       = sh_tmu_id_table,
669 };
670 
671 static int __init sh_tmu_init(void)
672 {
673         return platform_driver_register(&sh_tmu_device_driver);
674 }
675 
676 static void __exit sh_tmu_exit(void)
677 {
678         platform_driver_unregister(&sh_tmu_device_driver);
679 }
680 
681 early_platform_init("earlytimer", &sh_tmu_device_driver);
682 subsys_initcall(sh_tmu_init);
683 module_exit(sh_tmu_exit);
684 
685 MODULE_AUTHOR("Magnus Damm");
686 MODULE_DESCRIPTION("SuperH TMU Timer Driver");
687 MODULE_LICENSE("GPL v2");
688 

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