drivers/clocksource/sh_tmu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SuperH Timer Support - TMU
   4  *
   5  *  Copyright (C) 2009 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/platform_device.h>
  21 #include <linux/pm_domain.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/sh_timer.h>
  24 #include <linux/slab.h>
  25 #include <linux/spinlock.h>
  26
  27 #ifdef CONFIG_SUPERH
  28 #include <asm/platform_early.h>
  29 #endif
  30
  31 enum sh_tmu_model {
  32         SH_TMU,
  33         SH_TMU_SH3,
  34 };
  35
  36 struct sh_tmu_device;
  37
  38 struct sh_tmu_channel {
  39         struct sh_tmu_device *tmu;
  40         unsigned int index;
  41
  42         void __iomem *base;
  43         int irq;
  44
  45         unsigned long periodic;
  46         struct clock_event_device ced;
  47         struct clocksource cs;
  48         bool cs_enabled;
  49         unsigned int enable_count;
  50 };
  51
  52 struct sh_tmu_device {
  53         struct platform_device *pdev;
  54
  55         void __iomem *mapbase;
  56         struct clk *clk;
  57         unsigned long rate;
  58
  59         enum sh_tmu_model model;
  60
  61         raw_spinlock_t lock; /* Protect the shared start/stop register */
  62
  63         struct sh_tmu_channel *channels;
  64         unsigned int num_channels;
  65
  66         bool has_clockevent;
  67         bool has_clocksource;
  68 };
  69
  70 #define TSTR -1 /* shared register */
  71 #define TCOR  0 /* channel register */
  72 #define TCNT 1 /* channel register */
  73 #define TCR 2 /* channel register */
  74
  75 #define TCR_UNF                 (1 << 8)
  76 #define TCR_UNIE                (1 << 5)
  77 #define TCR_TPSC_CLK4           (0 << 0)
  78 #define TCR_TPSC_CLK16          (1 << 0)
  79 #define TCR_TPSC_CLK64          (2 << 0)
  80 #define TCR_TPSC_CLK256         (3 << 0)
  81 #define TCR_TPSC_CLK1024        (4 << 0)
  82 #define TCR_TPSC_MASK           (7 << 0)
  83
  84 static inline unsigned long sh_tmu_read(struct sh_tmu_channel *ch, int reg_nr)
  85 {
  86         unsigned long offs;
  87
  88         if (reg_nr == TSTR) {
  89                 switch (ch->tmu->model) {
  90                 case SH_TMU_SH3:
  91                         return ioread8(ch->tmu->mapbase + 2);
  92                 case SH_TMU:
  93                         return ioread8(ch->tmu->mapbase + 4);
  94                 }
  95         }
  96
  97         offs = reg_nr << 2;
  98
  99         if (reg_nr == TCR)
 100                 return ioread16(ch->base + offs);
 101         else
 102                 return ioread32(ch->base + offs);
 103 }
 104
 105 static inline void sh_tmu_write(struct sh_tmu_channel *ch, int reg_nr,
 106                                 unsigned long value)
 107 {
 108         unsigned long offs;
 109
 110         if (reg_nr == TSTR) {
 111                 switch (ch->tmu->model) {
 112                 case SH_TMU_SH3:
 113                         return iowrite8(value, ch->tmu->mapbase + 2);
 114                 case SH_TMU:
 115                         return iowrite8(value, ch->tmu->mapbase + 4);
 116                 }
 117         }
 118
 119         offs = reg_nr << 2;
 120
 121         if (reg_nr == TCR)
 122                 iowrite16(value, ch->base + offs);
 123         else
 124                 iowrite32(value, ch->base + offs);
 125 }
 126
 127 static void sh_tmu_start_stop_ch(struct sh_tmu_channel *ch, int start)
 128 {
 129         unsigned long flags, value;
 130
 131         /* start stop register shared by multiple timer channels */
 132         raw_spin_lock_irqsave(&ch->tmu->lock, flags);
 133         value = sh_tmu_read(ch, TSTR);
 134
 135         if (start)
 136                 value |= 1 << ch->index;
 137         else
 138                 value &= ~(1 << ch->index);
 139
 140         sh_tmu_write(ch, TSTR, value);
 141         raw_spin_unlock_irqrestore(&ch->tmu->lock, flags);
 142 }
 143
 144 static int __sh_tmu_enable(struct sh_tmu_channel *ch)
 145 {
 146         int ret;
 147
 148         /* enable clock */
 149         ret = clk_enable(ch->tmu->clk);
 150         if (ret) {
 151                 dev_err(&ch->tmu->pdev->dev, "ch%u: cannot enable clock\n",
 152                         ch->index);
 153                 return ret;
 154         }
 155
 156         /* make sure channel is disabled */
 157         sh_tmu_start_stop_ch(ch, 0);
 158
 159         /* maximum timeout */
 160         sh_tmu_write(ch, TCOR, 0xffffffff);
 161         sh_tmu_write(ch, TCNT, 0xffffffff);
 162
 163         /* configure channel to parent clock / 4, irq off */
 164         sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
 165
 166         /* enable channel */
 167         sh_tmu_start_stop_ch(ch, 1);
 168
 169         return 0;
 170 }
 171
 172 static int sh_tmu_enable(struct sh_tmu_channel *ch)
 173 {
 174         if (ch->enable_count++ > 0)
 175                 return 0;
 176
 177         pm_runtime_get_sync(&ch->tmu->pdev->dev);
 178         dev_pm_syscore_device(&ch->tmu->pdev->dev, true);
 179
 180         return __sh_tmu_enable(ch);
 181 }
 182
 183 static void __sh_tmu_disable(struct sh_tmu_channel *ch)
 184 {
 185         /* disable channel */
 186         sh_tmu_start_stop_ch(ch, 0);
 187
 188         /* disable interrupts in TMU block */
 189         sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
 190
 191         /* stop clock */
 192         clk_disable(ch->tmu->clk);
 193 }
 194
 195 static void sh_tmu_disable(struct sh_tmu_channel *ch)
 196 {
 197         if (WARN_ON(ch->enable_count == 0))
 198                 return;
 199
 200         if (--ch->enable_count > 0)
 201                 return;
 202
 203         __sh_tmu_disable(ch);
 204
 205         dev_pm_syscore_device(&ch->tmu->pdev->dev, false);
 206         pm_runtime_put(&ch->tmu->pdev->dev);
 207 }
 208
 209 static void sh_tmu_set_next(struct sh_tmu_channel *ch, unsigned long delta,
 210                             int periodic)
 211 {
 212         /* stop timer */
 213         sh_tmu_start_stop_ch(ch, 0);
 214
 215         /* acknowledge interrupt */
 216         sh_tmu_read(ch, TCR);
 217
 218         /* enable interrupt */
 219         sh_tmu_write(ch, TCR, TCR_UNIE | TCR_TPSC_CLK4);
 220
 221         /* reload delta value in case of periodic timer */
 222         if (periodic)
 223                 sh_tmu_write(ch, TCOR, delta);
 224         else
 225                 sh_tmu_write(ch, TCOR, 0xffffffff);
 226
 227         sh_tmu_write(ch, TCNT, delta);
 228
 229         /* start timer */
 230         sh_tmu_start_stop_ch(ch, 1);
 231 }
 232
 233 static irqreturn_t sh_tmu_interrupt(int irq, void *dev_id)
 234 {
 235         struct sh_tmu_channel *ch = dev_id;
 236
 237         /* disable or acknowledge interrupt */
 238         if (clockevent_state_oneshot(&ch->ced))
 239                 sh_tmu_write(ch, TCR, TCR_TPSC_CLK4);
 240         else
 241                 sh_tmu_write(ch, TCR, TCR_UNIE | TCR_TPSC_CLK4);
 242
 243         /* notify clockevent layer */
 244         ch->ced.event_handler(&ch->ced);
 245         return IRQ_HANDLED;
 246 }
 247
 248 static struct sh_tmu_channel *cs_to_sh_tmu(struct clocksource *cs)
 249 {
 250         return container_of(cs, struct sh_tmu_channel, cs);
 251 }
 252
 253 static u64 sh_tmu_clocksource_read(struct clocksource *cs)
 254 {
 255         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
 256
 257         return sh_tmu_read(ch, TCNT) ^ 0xffffffff;
 258 }
 259
 260 static int sh_tmu_clocksource_enable(struct clocksource *cs)
 261 {
 262         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
 263         int ret;
 264
 265         if (WARN_ON(ch->cs_enabled))
 266                 return 0;
 267
 268         ret = sh_tmu_enable(ch);
 269         if (!ret)
 270                 ch->cs_enabled = true;
 271
 272         return ret;
 273 }
 274
 275 static void sh_tmu_clocksource_disable(struct clocksource *cs)
 276 {
 277         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
 278
 279         if (WARN_ON(!ch->cs_enabled))
 280                 return;
 281
 282         sh_tmu_disable(ch);
 283         ch->cs_enabled = false;
 284 }
 285
 286 static void sh_tmu_clocksource_suspend(struct clocksource *cs)
 287 {
 288         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
 289
 290         if (!ch->cs_enabled)
 291                 return;
 292
 293         if (--ch->enable_count == 0) {
 294                 __sh_tmu_disable(ch);
 295                 dev_pm_genpd_suspend(&ch->tmu->pdev->dev);
 296         }
 297 }
 298
 299 static void sh_tmu_clocksource_resume(struct clocksource *cs)
 300 {
 301         struct sh_tmu_channel *ch = cs_to_sh_tmu(cs);
 302
 303         if (!ch->cs_enabled)
 304                 return;
 305
 306         if (ch->enable_count++ == 0) {
 307                 dev_pm_genpd_resume(&ch->tmu->pdev->dev);
 308                 __sh_tmu_enable(ch);
 309         }
 310 }
 311
 312 static int sh_tmu_register_clocksource(struct sh_tmu_channel *ch,
 313                                        const char *name)
 314 {
 315         struct clocksource *cs = &ch->cs;
 316
 317         cs->name = name;
 318         cs->rating = 200;
 319         cs->read = sh_tmu_clocksource_read;
 320         cs->enable = sh_tmu_clocksource_enable;
 321         cs->disable = sh_tmu_clocksource_disable;
 322         cs->suspend = sh_tmu_clocksource_suspend;
 323         cs->resume = sh_tmu_clocksource_resume;
 324         cs->mask = CLOCKSOURCE_MASK(32);
 325         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
 326
 327         dev_info(&ch->tmu->pdev->dev, "ch%u: used as clock source\n",
 328                  ch->index);
 329
 330         clocksource_register_hz(cs, ch->tmu->rate);
 331         return 0;
 332 }
 333
 334 static struct sh_tmu_channel *ced_to_sh_tmu(struct clock_event_device *ced)
 335 {
 336         return container_of(ced, struct sh_tmu_channel, ced);
 337 }
 338
 339 static void sh_tmu_clock_event_start(struct sh_tmu_channel *ch, int periodic)
 340 {
 341         sh_tmu_enable(ch);
 342
 343         if (periodic) {
 344                 ch->periodic = (ch->tmu->rate + HZ/2) / HZ;
 345                 sh_tmu_set_next(ch, ch->periodic, 1);
 346         }
 347 }
 348
 349 static int sh_tmu_clock_event_shutdown(struct clock_event_device *ced)
 350 {
 351         struct sh_tmu_channel *ch = ced_to_sh_tmu(ced);
 352
 353         if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
 354                 sh_tmu_disable(ch);
 355         return 0;
 356 }
 357
 358 static int sh_tmu_clock_event_set_state(struct clock_event_device *ced,
 359                                         int periodic)
 360 {
 361         struct sh_tmu_channel *ch = ced_to_sh_tmu(ced);
 362
 363         /* deal with old setting first */
 364         if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
 365                 sh_tmu_disable(ch);
 366
 367         dev_info(&ch->tmu->pdev->dev, "ch%u: used for %s clock events\n",
 368                  ch->index, periodic ? "periodic" : "oneshot");
 369         sh_tmu_clock_event_start(ch, periodic);
 370         return 0;
 371 }
 372
 373 static int sh_tmu_clock_event_set_oneshot(struct clock_event_device *ced)
 374 {
 375         return sh_tmu_clock_event_set_state(ced, 0);
 376 }
 377
 378 static int sh_tmu_clock_event_set_periodic(struct clock_event_device *ced)
 379 {
 380         return sh_tmu_clock_event_set_state(ced, 1);
 381 }
 382
 383 static int sh_tmu_clock_event_next(unsigned long delta,
 384                                    struct clock_event_device *ced)
 385 {
 386         struct sh_tmu_channel *ch = ced_to_sh_tmu(ced);
 387
 388         BUG_ON(!clockevent_state_oneshot(ced));
 389
 390         /* program new delta value */
 391         sh_tmu_set_next(ch, delta, 0);
 392         return 0;
 393 }
 394
 395 static void sh_tmu_clock_event_suspend(struct clock_event_device *ced)
 396 {
 397         dev_pm_genpd_suspend(&ced_to_sh_tmu(ced)->tmu->pdev->dev);
 398 }
 399
 400 static void sh_tmu_clock_event_resume(struct clock_event_device *ced)
 401 {
 402         dev_pm_genpd_resume(&ced_to_sh_tmu(ced)->tmu->pdev->dev);
 403 }
 404
 405 static void sh_tmu_register_clockevent(struct sh_tmu_channel *ch,
 406                                        const char *name)
 407 {
 408         struct clock_event_device *ced = &ch->ced;
 409         int ret;
 410
 411         ced->name = name;
 412         ced->features = CLOCK_EVT_FEAT_PERIODIC;
 413         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
 414         ced->rating = 200;
 415         ced->cpumask = cpu_possible_mask;
 416         ced->set_next_event = sh_tmu_clock_event_next;
 417         ced->set_state_shutdown = sh_tmu_clock_event_shutdown;
 418         ced->set_state_periodic = sh_tmu_clock_event_set_periodic;
 419         ced->set_state_oneshot = sh_tmu_clock_event_set_oneshot;
 420         ced->suspend = sh_tmu_clock_event_suspend;
 421         ced->resume = sh_tmu_clock_event_resume;
 422
 423         dev_info(&ch->tmu->pdev->dev, "ch%u: used for clock events\n",
 424                  ch->index);
 425
 426         clockevents_config_and_register(ced, ch->tmu->rate, 0x300, 0xffffffff);
 427
 428         ret = request_irq(ch->irq, sh_tmu_interrupt,
 429                           IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
 430                           dev_name(&ch->tmu->pdev->dev), ch);
 431         if (ret) {
 432                 dev_err(&ch->tmu->pdev->dev, "ch%u: failed to request irq %d\n",
 433                         ch->index, ch->irq);
 434                 return;
 435         }
 436 }
 437
 438 static int sh_tmu_register(struct sh_tmu_channel *ch, const char *name,
 439                            bool clockevent, bool clocksource)
 440 {
 441         if (clockevent) {
 442                 ch->tmu->has_clockevent = true;
 443                 sh_tmu_register_clockevent(ch, name);
 444         } else if (clocksource) {
 445                 ch->tmu->has_clocksource = true;
 446                 sh_tmu_register_clocksource(ch, name);
 447         }
 448
 449         return 0;
 450 }
 451
 452 static int sh_tmu_channel_setup(struct sh_tmu_channel *ch, unsigned int index,
 453                                 bool clockevent, bool clocksource,
 454                                 struct sh_tmu_device *tmu)
 455 {
 456         /* Skip unused channels. */
 457         if (!clockevent && !clocksource)
 458                 return 0;
 459
 460         ch->tmu = tmu;
 461         ch->index = index;
 462
 463         if (tmu->model == SH_TMU_SH3)
 464                 ch->base = tmu->mapbase + 4 + ch->index * 12;
 465         else
 466                 ch->base = tmu->mapbase + 8 + ch->index * 12;
 467
 468         ch->irq = platform_get_irq(tmu->pdev, index);
 469         if (ch->irq < 0)
 470                 return ch->irq;
 471
 472         ch->cs_enabled = false;
 473         ch->enable_count = 0;
 474
 475         return sh_tmu_register(ch, dev_name(&tmu->pdev->dev),
 476                                clockevent, clocksource);
 477 }
 478
 479 static int sh_tmu_map_memory(struct sh_tmu_device *tmu)
 480 {
 481         struct resource *res;
 482
 483         res = platform_get_resource(tmu->pdev, IORESOURCE_MEM, 0);
 484         if (!res) {
 485                 dev_err(&tmu->pdev->dev, "failed to get I/O memory\n");
 486                 return -ENXIO;
 487         }
 488
 489         tmu->mapbase = ioremap(res->start, resource_size(res));
 490         if (tmu->mapbase == NULL)
 491                 return -ENXIO;
 492
 493         return 0;
 494 }
 495
 496 static int sh_tmu_parse_dt(struct sh_tmu_device *tmu)
 497 {
 498         struct device_node *np = tmu->pdev->dev.of_node;
 499
 500         tmu->model = SH_TMU;
 501         tmu->num_channels = 3;
 502
 503         of_property_read_u32(np, "#renesas,channels", &tmu->num_channels);
 504
 505         if (tmu->num_channels != 2 && tmu->num_channels != 3) {
 506                 dev_err(&tmu->pdev->dev, "invalid number of channels %u\n",
 507                         tmu->num_channels);
 508                 return -EINVAL;
 509         }
 510
 511         return 0;
 512 }
 513
 514 static int sh_tmu_setup(struct sh_tmu_device *tmu, struct platform_device *pdev)
 515 {
 516         unsigned int i;
 517         int ret;
 518
 519         tmu->pdev = pdev;
 520
 521         raw_spin_lock_init(&tmu->lock);
 522
 523         if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
 524                 ret = sh_tmu_parse_dt(tmu);
 525                 if (ret < 0)
 526                         return ret;
 527         } else if (pdev->dev.platform_data) {
 528                 const struct platform_device_id *id = pdev->id_entry;
 529                 struct sh_timer_config *cfg = pdev->dev.platform_data;
 530
 531                 tmu->model = id->driver_data;
 532                 tmu->num_channels = hweight8(cfg->channels_mask);
 533         } else {
 534                 dev_err(&tmu->pdev->dev, "missing platform data\n");
 535                 return -ENXIO;
 536         }
 537
 538         /* Get hold of clock. */
 539         tmu->clk = clk_get(&tmu->pdev->dev, "fck");
 540         if (IS_ERR(tmu->clk)) {
 541                 dev_err(&tmu->pdev->dev, "cannot get clock\n");
 542                 return PTR_ERR(tmu->clk);
 543         }
 544
 545         ret = clk_prepare(tmu->clk);
 546         if (ret < 0)
 547                 goto err_clk_put;
 548
 549         /* Determine clock rate. */
 550         ret = clk_enable(tmu->clk);
 551         if (ret < 0)
 552                 goto err_clk_unprepare;
 553
 554         tmu->rate = clk_get_rate(tmu->clk) / 4;
 555         clk_disable(tmu->clk);
 556
 557         /* Map the memory resource. */
 558         ret = sh_tmu_map_memory(tmu);
 559         if (ret < 0) {
 560                 dev_err(&tmu->pdev->dev, "failed to remap I/O memory\n");
 561                 goto err_clk_unprepare;
 562         }
 563
 564         /* Allocate and setup the channels. */
 565         tmu->channels = kcalloc(tmu->num_channels, sizeof(*tmu->channels),
 566                                 GFP_KERNEL);
 567         if (tmu->channels == NULL) {
 568                 ret = -ENOMEM;
 569                 goto err_unmap;
 570         }
 571
 572         /*
 573          * Use the first channel as a clock event device and the second channel
 574          * as a clock source.
 575          */
 576         for (i = 0; i < tmu->num_channels; ++i) {
 577                 ret = sh_tmu_channel_setup(&tmu->channels[i], i,
 578                                            i == 0, i == 1, tmu);
 579                 if (ret < 0)
 580                         goto err_unmap;
 581         }
 582
 583         platform_set_drvdata(pdev, tmu);
 584
 585         return 0;
 586
 587 err_unmap:
 588         kfree(tmu->channels);
 589         iounmap(tmu->mapbase);
 590 err_clk_unprepare:
 591         clk_unprepare(tmu->clk);
 592 err_clk_put:
 593         clk_put(tmu->clk);
 594         return ret;
 595 }
 596
 597 static int sh_tmu_probe(struct platform_device *pdev)
 598 {
 599         struct sh_tmu_device *tmu = platform_get_drvdata(pdev);
 600         int ret;
 601
 602         if (!is_sh_early_platform_device(pdev)) {
 603                 pm_runtime_set_active(&pdev->dev);
 604                 pm_runtime_enable(&pdev->dev);
 605         }
 606
 607         if (tmu) {
 608                 dev_info(&pdev->dev, "kept as earlytimer\n");
 609                 goto out;
 610         }
 611
 612         tmu = kzalloc(sizeof(*tmu), GFP_KERNEL);
 613         if (tmu == NULL)
 614                 return -ENOMEM;
 615
 616         ret = sh_tmu_setup(tmu, pdev);
 617         if (ret) {
 618                 kfree(tmu);
 619                 pm_runtime_idle(&pdev->dev);
 620                 return ret;
 621         }
 622
 623         if (is_sh_early_platform_device(pdev))
 624                 return 0;
 625
 626  out:
 627         if (tmu->has_clockevent || tmu->has_clocksource)
 628                 pm_runtime_irq_safe(&pdev->dev);
 629         else
 630                 pm_runtime_idle(&pdev->dev);
 631
 632         return 0;
 633 }
 634
 635 static int sh_tmu_remove(struct platform_device *pdev)
 636 {
 637         return -EBUSY; /* cannot unregister clockevent and clocksource */
 638 }
 639
 640 static const struct platform_device_id sh_tmu_id_table[] = {
 641         { "sh-tmu", SH_TMU },
 642         { "sh-tmu-sh3", SH_TMU_SH3 },
 643         { }
 644 };
 645 MODULE_DEVICE_TABLE(platform, sh_tmu_id_table);
 646
 647 static const struct of_device_id sh_tmu_of_table[] __maybe_unused = {
 648         { .compatible = "renesas,tmu" },
 649         { }
 650 };
 651 MODULE_DEVICE_TABLE(of, sh_tmu_of_table);
 652
 653 static struct platform_driver sh_tmu_device_driver = {
 654         .probe          = sh_tmu_probe,
 655         .remove         = sh_tmu_remove,
 656         .driver         = {
 657                 .name   = "sh_tmu",
 658                 .of_match_table = of_match_ptr(sh_tmu_of_table),
 659         },
 660         .id_table       = sh_tmu_id_table,
 661 };
 662
 663 static int __init sh_tmu_init(void)
 664 {
 665         return platform_driver_register(&sh_tmu_device_driver);
 666 }
 667
 668 static void __exit sh_tmu_exit(void)
 669 {
 670         platform_driver_unregister(&sh_tmu_device_driver);
 671 }
 672
 673 #ifdef CONFIG_SUPERH
 674 sh_early_platform_init("earlytimer", &sh_tmu_device_driver);
 675 #endif
 676
 677 subsys_initcall(sh_tmu_init);
 678 module_exit(sh_tmu_exit);
 679
 680 MODULE_AUTHOR("Magnus Damm");
 681 MODULE_DESCRIPTION("SuperH TMU Timer Driver");
 682 MODULE_LICENSE("GPL v2");