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Linux/drivers/clocksource/sh_mtu2.c

  1 /*
  2  * SuperH Timer Support - MTU2
  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/delay.h>
 19 #include <linux/err.h>
 20 #include <linux/init.h>
 21 #include <linux/interrupt.h>
 22 #include <linux/io.h>
 23 #include <linux/ioport.h>
 24 #include <linux/irq.h>
 25 #include <linux/module.h>
 26 #include <linux/of.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 struct sh_mtu2_device;
 35 
 36 struct sh_mtu2_channel {
 37         struct sh_mtu2_device *mtu;
 38         unsigned int index;
 39 
 40         void __iomem *base;
 41 
 42         struct clock_event_device ced;
 43 };
 44 
 45 struct sh_mtu2_device {
 46         struct platform_device *pdev;
 47 
 48         void __iomem *mapbase;
 49         struct clk *clk;
 50 
 51         raw_spinlock_t lock; /* Protect the shared registers */
 52 
 53         struct sh_mtu2_channel *channels;
 54         unsigned int num_channels;
 55 
 56         bool has_clockevent;
 57 };
 58 
 59 #define TSTR -1 /* shared register */
 60 #define TCR  0 /* channel register */
 61 #define TMDR 1 /* channel register */
 62 #define TIOR 2 /* channel register */
 63 #define TIER 3 /* channel register */
 64 #define TSR  4 /* channel register */
 65 #define TCNT 5 /* channel register */
 66 #define TGR  6 /* channel register */
 67 
 68 #define TCR_CCLR_NONE           (0 << 5)
 69 #define TCR_CCLR_TGRA           (1 << 5)
 70 #define TCR_CCLR_TGRB           (2 << 5)
 71 #define TCR_CCLR_SYNC           (3 << 5)
 72 #define TCR_CCLR_TGRC           (5 << 5)
 73 #define TCR_CCLR_TGRD           (6 << 5)
 74 #define TCR_CCLR_MASK           (7 << 5)
 75 #define TCR_CKEG_RISING         (0 << 3)
 76 #define TCR_CKEG_FALLING        (1 << 3)
 77 #define TCR_CKEG_BOTH           (2 << 3)
 78 #define TCR_CKEG_MASK           (3 << 3)
 79 /* Values 4 to 7 are channel-dependent */
 80 #define TCR_TPSC_P1             (0 << 0)
 81 #define TCR_TPSC_P4             (1 << 0)
 82 #define TCR_TPSC_P16            (2 << 0)
 83 #define TCR_TPSC_P64            (3 << 0)
 84 #define TCR_TPSC_CH0_TCLKA      (4 << 0)
 85 #define TCR_TPSC_CH0_TCLKB      (5 << 0)
 86 #define TCR_TPSC_CH0_TCLKC      (6 << 0)
 87 #define TCR_TPSC_CH0_TCLKD      (7 << 0)
 88 #define TCR_TPSC_CH1_TCLKA      (4 << 0)
 89 #define TCR_TPSC_CH1_TCLKB      (5 << 0)
 90 #define TCR_TPSC_CH1_P256       (6 << 0)
 91 #define TCR_TPSC_CH1_TCNT2      (7 << 0)
 92 #define TCR_TPSC_CH2_TCLKA      (4 << 0)
 93 #define TCR_TPSC_CH2_TCLKB      (5 << 0)
 94 #define TCR_TPSC_CH2_TCLKC      (6 << 0)
 95 #define TCR_TPSC_CH2_P1024      (7 << 0)
 96 #define TCR_TPSC_CH34_P256      (4 << 0)
 97 #define TCR_TPSC_CH34_P1024     (5 << 0)
 98 #define TCR_TPSC_CH34_TCLKA     (6 << 0)
 99 #define TCR_TPSC_CH34_TCLKB     (7 << 0)
100 #define TCR_TPSC_MASK           (7 << 0)
101 
102 #define TMDR_BFE                (1 << 6)
103 #define TMDR_BFB                (1 << 5)
104 #define TMDR_BFA                (1 << 4)
105 #define TMDR_MD_NORMAL          (0 << 0)
106 #define TMDR_MD_PWM_1           (2 << 0)
107 #define TMDR_MD_PWM_2           (3 << 0)
108 #define TMDR_MD_PHASE_1         (4 << 0)
109 #define TMDR_MD_PHASE_2         (5 << 0)
110 #define TMDR_MD_PHASE_3         (6 << 0)
111 #define TMDR_MD_PHASE_4         (7 << 0)
112 #define TMDR_MD_PWM_SYNC        (8 << 0)
113 #define TMDR_MD_PWM_COMP_CREST  (13 << 0)
114 #define TMDR_MD_PWM_COMP_TROUGH (14 << 0)
115 #define TMDR_MD_PWM_COMP_BOTH   (15 << 0)
116 #define TMDR_MD_MASK            (15 << 0)
117 
118 #define TIOC_IOCH(n)            ((n) << 4)
119 #define TIOC_IOCL(n)            ((n) << 0)
120 #define TIOR_OC_RETAIN          (0 << 0)
121 #define TIOR_OC_0_CLEAR         (1 << 0)
122 #define TIOR_OC_0_SET           (2 << 0)
123 #define TIOR_OC_0_TOGGLE        (3 << 0)
124 #define TIOR_OC_1_CLEAR         (5 << 0)
125 #define TIOR_OC_1_SET           (6 << 0)
126 #define TIOR_OC_1_TOGGLE        (7 << 0)
127 #define TIOR_IC_RISING          (8 << 0)
128 #define TIOR_IC_FALLING         (9 << 0)
129 #define TIOR_IC_BOTH            (10 << 0)
130 #define TIOR_IC_TCNT            (12 << 0)
131 #define TIOR_MASK               (15 << 0)
132 
133 #define TIER_TTGE               (1 << 7)
134 #define TIER_TTGE2              (1 << 6)
135 #define TIER_TCIEU              (1 << 5)
136 #define TIER_TCIEV              (1 << 4)
137 #define TIER_TGIED              (1 << 3)
138 #define TIER_TGIEC              (1 << 2)
139 #define TIER_TGIEB              (1 << 1)
140 #define TIER_TGIEA              (1 << 0)
141 
142 #define TSR_TCFD                (1 << 7)
143 #define TSR_TCFU                (1 << 5)
144 #define TSR_TCFV                (1 << 4)
145 #define TSR_TGFD                (1 << 3)
146 #define TSR_TGFC                (1 << 2)
147 #define TSR_TGFB                (1 << 1)
148 #define TSR_TGFA                (1 << 0)
149 
150 static unsigned long mtu2_reg_offs[] = {
151         [TCR] = 0,
152         [TMDR] = 1,
153         [TIOR] = 2,
154         [TIER] = 4,
155         [TSR] = 5,
156         [TCNT] = 6,
157         [TGR] = 8,
158 };
159 
160 static inline unsigned long sh_mtu2_read(struct sh_mtu2_channel *ch, int reg_nr)
161 {
162         unsigned long offs;
163 
164         if (reg_nr == TSTR)
165                 return ioread8(ch->mtu->mapbase + 0x280);
166 
167         offs = mtu2_reg_offs[reg_nr];
168 
169         if ((reg_nr == TCNT) || (reg_nr == TGR))
170                 return ioread16(ch->base + offs);
171         else
172                 return ioread8(ch->base + offs);
173 }
174 
175 static inline void sh_mtu2_write(struct sh_mtu2_channel *ch, int reg_nr,
176                                 unsigned long value)
177 {
178         unsigned long offs;
179 
180         if (reg_nr == TSTR)
181                 return iowrite8(value, ch->mtu->mapbase + 0x280);
182 
183         offs = mtu2_reg_offs[reg_nr];
184 
185         if ((reg_nr == TCNT) || (reg_nr == TGR))
186                 iowrite16(value, ch->base + offs);
187         else
188                 iowrite8(value, ch->base + offs);
189 }
190 
191 static void sh_mtu2_start_stop_ch(struct sh_mtu2_channel *ch, int start)
192 {
193         unsigned long flags, value;
194 
195         /* start stop register shared by multiple timer channels */
196         raw_spin_lock_irqsave(&ch->mtu->lock, flags);
197         value = sh_mtu2_read(ch, TSTR);
198 
199         if (start)
200                 value |= 1 << ch->index;
201         else
202                 value &= ~(1 << ch->index);
203 
204         sh_mtu2_write(ch, TSTR, value);
205         raw_spin_unlock_irqrestore(&ch->mtu->lock, flags);
206 }
207 
208 static int sh_mtu2_enable(struct sh_mtu2_channel *ch)
209 {
210         unsigned long periodic;
211         unsigned long rate;
212         int ret;
213 
214         pm_runtime_get_sync(&ch->mtu->pdev->dev);
215         dev_pm_syscore_device(&ch->mtu->pdev->dev, true);
216 
217         /* enable clock */
218         ret = clk_enable(ch->mtu->clk);
219         if (ret) {
220                 dev_err(&ch->mtu->pdev->dev, "ch%u: cannot enable clock\n",
221                         ch->index);
222                 return ret;
223         }
224 
225         /* make sure channel is disabled */
226         sh_mtu2_start_stop_ch(ch, 0);
227 
228         rate = clk_get_rate(ch->mtu->clk) / 64;
229         periodic = (rate + HZ/2) / HZ;
230 
231         /*
232          * "Periodic Counter Operation"
233          * Clear on TGRA compare match, divide clock by 64.
234          */
235         sh_mtu2_write(ch, TCR, TCR_CCLR_TGRA | TCR_TPSC_P64);
236         sh_mtu2_write(ch, TIOR, TIOC_IOCH(TIOR_OC_0_CLEAR) |
237                       TIOC_IOCL(TIOR_OC_0_CLEAR));
238         sh_mtu2_write(ch, TGR, periodic);
239         sh_mtu2_write(ch, TCNT, 0);
240         sh_mtu2_write(ch, TMDR, TMDR_MD_NORMAL);
241         sh_mtu2_write(ch, TIER, TIER_TGIEA);
242 
243         /* enable channel */
244         sh_mtu2_start_stop_ch(ch, 1);
245 
246         return 0;
247 }
248 
249 static void sh_mtu2_disable(struct sh_mtu2_channel *ch)
250 {
251         /* disable channel */
252         sh_mtu2_start_stop_ch(ch, 0);
253 
254         /* stop clock */
255         clk_disable(ch->mtu->clk);
256 
257         dev_pm_syscore_device(&ch->mtu->pdev->dev, false);
258         pm_runtime_put(&ch->mtu->pdev->dev);
259 }
260 
261 static irqreturn_t sh_mtu2_interrupt(int irq, void *dev_id)
262 {
263         struct sh_mtu2_channel *ch = dev_id;
264 
265         /* acknowledge interrupt */
266         sh_mtu2_read(ch, TSR);
267         sh_mtu2_write(ch, TSR, ~TSR_TGFA);
268 
269         /* notify clockevent layer */
270         ch->ced.event_handler(&ch->ced);
271         return IRQ_HANDLED;
272 }
273 
274 static struct sh_mtu2_channel *ced_to_sh_mtu2(struct clock_event_device *ced)
275 {
276         return container_of(ced, struct sh_mtu2_channel, ced);
277 }
278 
279 static int sh_mtu2_clock_event_shutdown(struct clock_event_device *ced)
280 {
281         struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);
282 
283         if (clockevent_state_periodic(ced))
284                 sh_mtu2_disable(ch);
285 
286         return 0;
287 }
288 
289 static int sh_mtu2_clock_event_set_periodic(struct clock_event_device *ced)
290 {
291         struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);
292 
293         if (clockevent_state_periodic(ced))
294                 sh_mtu2_disable(ch);
295 
296         dev_info(&ch->mtu->pdev->dev, "ch%u: used for periodic clock events\n",
297                  ch->index);
298         sh_mtu2_enable(ch);
299         return 0;
300 }
301 
302 static void sh_mtu2_clock_event_suspend(struct clock_event_device *ced)
303 {
304         pm_genpd_syscore_poweroff(&ced_to_sh_mtu2(ced)->mtu->pdev->dev);
305 }
306 
307 static void sh_mtu2_clock_event_resume(struct clock_event_device *ced)
308 {
309         pm_genpd_syscore_poweron(&ced_to_sh_mtu2(ced)->mtu->pdev->dev);
310 }
311 
312 static void sh_mtu2_register_clockevent(struct sh_mtu2_channel *ch,
313                                         const char *name)
314 {
315         struct clock_event_device *ced = &ch->ced;
316 
317         ced->name = name;
318         ced->features = CLOCK_EVT_FEAT_PERIODIC;
319         ced->rating = 200;
320         ced->cpumask = cpu_possible_mask;
321         ced->set_state_shutdown = sh_mtu2_clock_event_shutdown;
322         ced->set_state_periodic = sh_mtu2_clock_event_set_periodic;
323         ced->suspend = sh_mtu2_clock_event_suspend;
324         ced->resume = sh_mtu2_clock_event_resume;
325 
326         dev_info(&ch->mtu->pdev->dev, "ch%u: used for clock events\n",
327                  ch->index);
328         clockevents_register_device(ced);
329 }
330 
331 static int sh_mtu2_register(struct sh_mtu2_channel *ch, const char *name)
332 {
333         ch->mtu->has_clockevent = true;
334         sh_mtu2_register_clockevent(ch, name);
335 
336         return 0;
337 }
338 
339 static int sh_mtu2_setup_channel(struct sh_mtu2_channel *ch, unsigned int index,
340                                  struct sh_mtu2_device *mtu)
341 {
342         static const unsigned int channel_offsets[] = {
343                 0x300, 0x380, 0x000,
344         };
345         char name[6];
346         int irq;
347         int ret;
348 
349         ch->mtu = mtu;
350 
351         sprintf(name, "tgi%ua", index);
352         irq = platform_get_irq_byname(mtu->pdev, name);
353         if (irq < 0) {
354                 /* Skip channels with no declared interrupt. */
355                 return 0;
356         }
357 
358         ret = request_irq(irq, sh_mtu2_interrupt,
359                           IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
360                           dev_name(&ch->mtu->pdev->dev), ch);
361         if (ret) {
362                 dev_err(&ch->mtu->pdev->dev, "ch%u: failed to request irq %d\n",
363                         index, irq);
364                 return ret;
365         }
366 
367         ch->base = mtu->mapbase + channel_offsets[index];
368         ch->index = index;
369 
370         return sh_mtu2_register(ch, dev_name(&mtu->pdev->dev));
371 }
372 
373 static int sh_mtu2_map_memory(struct sh_mtu2_device *mtu)
374 {
375         struct resource *res;
376 
377         res = platform_get_resource(mtu->pdev, IORESOURCE_MEM, 0);
378         if (!res) {
379                 dev_err(&mtu->pdev->dev, "failed to get I/O memory\n");
380                 return -ENXIO;
381         }
382 
383         mtu->mapbase = ioremap_nocache(res->start, resource_size(res));
384         if (mtu->mapbase == NULL)
385                 return -ENXIO;
386 
387         return 0;
388 }
389 
390 static int sh_mtu2_setup(struct sh_mtu2_device *mtu,
391                          struct platform_device *pdev)
392 {
393         unsigned int i;
394         int ret;
395 
396         mtu->pdev = pdev;
397 
398         raw_spin_lock_init(&mtu->lock);
399 
400         /* Get hold of clock. */
401         mtu->clk = clk_get(&mtu->pdev->dev, "fck");
402         if (IS_ERR(mtu->clk)) {
403                 dev_err(&mtu->pdev->dev, "cannot get clock\n");
404                 return PTR_ERR(mtu->clk);
405         }
406 
407         ret = clk_prepare(mtu->clk);
408         if (ret < 0)
409                 goto err_clk_put;
410 
411         /* Map the memory resource. */
412         ret = sh_mtu2_map_memory(mtu);
413         if (ret < 0) {
414                 dev_err(&mtu->pdev->dev, "failed to remap I/O memory\n");
415                 goto err_clk_unprepare;
416         }
417 
418         /* Allocate and setup the channels. */
419         mtu->num_channels = 3;
420 
421         mtu->channels = kzalloc(sizeof(*mtu->channels) * mtu->num_channels,
422                                 GFP_KERNEL);
423         if (mtu->channels == NULL) {
424                 ret = -ENOMEM;
425                 goto err_unmap;
426         }
427 
428         for (i = 0; i < mtu->num_channels; ++i) {
429                 ret = sh_mtu2_setup_channel(&mtu->channels[i], i, mtu);
430                 if (ret < 0)
431                         goto err_unmap;
432         }
433 
434         platform_set_drvdata(pdev, mtu);
435 
436         return 0;
437 
438 err_unmap:
439         kfree(mtu->channels);
440         iounmap(mtu->mapbase);
441 err_clk_unprepare:
442         clk_unprepare(mtu->clk);
443 err_clk_put:
444         clk_put(mtu->clk);
445         return ret;
446 }
447 
448 static int sh_mtu2_probe(struct platform_device *pdev)
449 {
450         struct sh_mtu2_device *mtu = platform_get_drvdata(pdev);
451         int ret;
452 
453         if (!is_early_platform_device(pdev)) {
454                 pm_runtime_set_active(&pdev->dev);
455                 pm_runtime_enable(&pdev->dev);
456         }
457 
458         if (mtu) {
459                 dev_info(&pdev->dev, "kept as earlytimer\n");
460                 goto out;
461         }
462 
463         mtu = kzalloc(sizeof(*mtu), GFP_KERNEL);
464         if (mtu == NULL)
465                 return -ENOMEM;
466 
467         ret = sh_mtu2_setup(mtu, pdev);
468         if (ret) {
469                 kfree(mtu);
470                 pm_runtime_idle(&pdev->dev);
471                 return ret;
472         }
473         if (is_early_platform_device(pdev))
474                 return 0;
475 
476  out:
477         if (mtu->has_clockevent)
478                 pm_runtime_irq_safe(&pdev->dev);
479         else
480                 pm_runtime_idle(&pdev->dev);
481 
482         return 0;
483 }
484 
485 static int sh_mtu2_remove(struct platform_device *pdev)
486 {
487         return -EBUSY; /* cannot unregister clockevent */
488 }
489 
490 static const struct platform_device_id sh_mtu2_id_table[] = {
491         { "sh-mtu2", 0 },
492         { },
493 };
494 MODULE_DEVICE_TABLE(platform, sh_mtu2_id_table);
495 
496 static const struct of_device_id sh_mtu2_of_table[] __maybe_unused = {
497         { .compatible = "renesas,mtu2" },
498         { }
499 };
500 MODULE_DEVICE_TABLE(of, sh_mtu2_of_table);
501 
502 static struct platform_driver sh_mtu2_device_driver = {
503         .probe          = sh_mtu2_probe,
504         .remove         = sh_mtu2_remove,
505         .driver         = {
506                 .name   = "sh_mtu2",
507                 .of_match_table = of_match_ptr(sh_mtu2_of_table),
508         },
509         .id_table       = sh_mtu2_id_table,
510 };
511 
512 static int __init sh_mtu2_init(void)
513 {
514         return platform_driver_register(&sh_mtu2_device_driver);
515 }
516 
517 static void __exit sh_mtu2_exit(void)
518 {
519         platform_driver_unregister(&sh_mtu2_device_driver);
520 }
521 
522 early_platform_init("earlytimer", &sh_mtu2_device_driver);
523 subsys_initcall(sh_mtu2_init);
524 module_exit(sh_mtu2_exit);
525 
526 MODULE_AUTHOR("Magnus Damm");
527 MODULE_DESCRIPTION("SuperH MTU2 Timer Driver");
528 MODULE_LICENSE("GPL v2");
529 

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