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  * 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/delay.h>
  26 #include <linux/io.h>
  27 #include <linux/clk.h>
  28 #include <linux/irq.h>
  29 #include <linux/err.h>
  30 #include <linux/clocksource.h>
  31 #include <linux/clockchips.h>
  32 #include <linux/sh_timer.h>
  33 #include <linux/slab.h>
  34 #include <linux/module.h>
  35 #include <linux/pm_domain.h>
  36 #include <linux/pm_runtime.h>
  37
  38 struct sh_tmu_priv {
  39         void __iomem *mapbase;
  40         struct clk *clk;
  41         struct irqaction irqaction;
  42         struct platform_device *pdev;
  43         unsigned long rate;
  44         unsigned long periodic;
  45         struct clock_event_device ced;
  46         struct clocksource cs;
  47         bool cs_enabled;
  48         unsigned int enable_count;
  49 };
  50
  51 static DEFINE_RAW_SPINLOCK(sh_tmu_lock);
  52
  53 #define TSTR -1 /* shared register */
  54 #define TCOR  0 /* channel register */
  55 #define TCNT 1 /* channel register */
  56 #define TCR 2 /* channel register */
  57
  58 static inline unsigned long sh_tmu_read(struct sh_tmu_priv *p, int reg_nr)
  59 {
  60         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  61         void __iomem *base = p->mapbase;
  62         unsigned long offs;
  63
  64         if (reg_nr == TSTR)
  65                 return ioread8(base - cfg->channel_offset);
  66
  67         offs = reg_nr << 2;
  68
  69         if (reg_nr == TCR)
  70                 return ioread16(base + offs);
  71         else
  72                 return ioread32(base + offs);
  73 }
  74
  75 static inline void sh_tmu_write(struct sh_tmu_priv *p, int reg_nr,
  76                                 unsigned long value)
  77 {
  78         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  79         void __iomem *base = p->mapbase;
  80         unsigned long offs;
  81
  82         if (reg_nr == TSTR) {
  83                 iowrite8(value, base - cfg->channel_offset);
  84                 return;
  85         }
  86
  87         offs = reg_nr << 2;
  88
  89         if (reg_nr == TCR)
  90                 iowrite16(value, base + offs);
  91         else
  92                 iowrite32(value, base + offs);
  93 }
  94
  95 static void sh_tmu_start_stop_ch(struct sh_tmu_priv *p, int start)
  96 {
  97         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  98         unsigned long flags, value;
  99
 100         /* start stop register shared by multiple timer channels */
 101         raw_spin_lock_irqsave(&sh_tmu_lock, flags);
 102         value = sh_tmu_read(p, TSTR);
 103
 104         if (start)
 105                 value |= 1 << cfg->timer_bit;
 106         else
 107                 value &= ~(1 << cfg->timer_bit);
 108
 109         sh_tmu_write(p, TSTR, value);
 110         raw_spin_unlock_irqrestore(&sh_tmu_lock, flags);
 111 }
 112
 113 static int __sh_tmu_enable(struct sh_tmu_priv *p)
 114 {
 115         int ret;
 116
 117         /* enable clock */
 118         ret = clk_enable(p->clk);
 119         if (ret) {
 120                 dev_err(&p->pdev->dev, "cannot enable clock\n");
 121                 return ret;
 122         }
 123
 124         /* make sure channel is disabled */
 125         sh_tmu_start_stop_ch(p, 0);
 126
 127         /* maximum timeout */
 128         sh_tmu_write(p, TCOR, 0xffffffff);
 129         sh_tmu_write(p, TCNT, 0xffffffff);
 130
 131         /* configure channel to parent clock / 4, irq off */
 132         p->rate = clk_get_rate(p->clk) / 4;
 133         sh_tmu_write(p, TCR, 0x0000);
 134
 135         /* enable channel */
 136         sh_tmu_start_stop_ch(p, 1);
 137
 138         return 0;
 139 }
 140
 141 static int sh_tmu_enable(struct sh_tmu_priv *p)
 142 {
 143         if (p->enable_count++ > 0)
 144                 return 0;
 145
 146         pm_runtime_get_sync(&p->pdev->dev);
 147         dev_pm_syscore_device(&p->pdev->dev, true);
 148
 149         return __sh_tmu_enable(p);
 150 }
 151
 152 static void __sh_tmu_disable(struct sh_tmu_priv *p)
 153 {
 154         /* disable channel */
 155         sh_tmu_start_stop_ch(p, 0);
 156
 157         /* disable interrupts in TMU block */
 158         sh_tmu_write(p, TCR, 0x0000);
 159
 160         /* stop clock */
 161         clk_disable(p->clk);
 162 }
 163
 164 static void sh_tmu_disable(struct sh_tmu_priv *p)
 165 {
 166         if (WARN_ON(p->enable_count == 0))
 167                 return;
 168
 169         if (--p->enable_count > 0)
 170                 return;
 171
 172         __sh_tmu_disable(p);
 173
 174         dev_pm_syscore_device(&p->pdev->dev, false);
 175         pm_runtime_put(&p->pdev->dev);
 176 }
 177
 178 static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
 179                             int periodic)
 180 {
 181         /* stop timer */
 182         sh_tmu_start_stop_ch(p, 0);
 183
 184         /* acknowledge interrupt */
 185         sh_tmu_read(p, TCR);
 186
 187         /* enable interrupt */
 188         sh_tmu_write(p, TCR, 0x0020);
 189
 190         /* reload delta value in case of periodic timer */
 191         if (periodic)
 192                 sh_tmu_write(p, TCOR, delta);
 193         else
 194                 sh_tmu_write(p, TCOR, 0xffffffff);
 195
 196         sh_tmu_write(p, TCNT, delta);
 197
 198         /* start timer */
 199         sh_tmu_start_stop_ch(p, 1);
 200 }
 201
 202 static irqreturn_t sh_tmu_interrupt(int irq, void *dev_id)
 203 {
 204         struct sh_tmu_priv *p = dev_id;
 205
 206         /* disable or acknowledge interrupt */
 207         if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT)
 208                 sh_tmu_write(p, TCR, 0x0000);
 209         else
 210                 sh_tmu_write(p, TCR, 0x0020);
 211
 212         /* notify clockevent layer */
 213         p->ced.event_handler(&p->ced);
 214         return IRQ_HANDLED;
 215 }
 216
 217 static struct sh_tmu_priv *cs_to_sh_tmu(struct clocksource *cs)
 218 {
 219         return container_of(cs, struct sh_tmu_priv, cs);
 220 }
 221
 222 static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
 223 {
 224         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 225
 226         return sh_tmu_read(p, TCNT) ^ 0xffffffff;
 227 }
 228
 229 static int sh_tmu_clocksource_enable(struct clocksource *cs)
 230 {
 231         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 232         int ret;
 233
 234         if (WARN_ON(p->cs_enabled))
 235                 return 0;
 236
 237         ret = sh_tmu_enable(p);
 238         if (!ret) {
 239                 __clocksource_updatefreq_hz(cs, p->rate);
 240                 p->cs_enabled = true;
 241         }
 242
 243         return ret;
 244 }
 245
 246 static void sh_tmu_clocksource_disable(struct clocksource *cs)
 247 {
 248         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 249
 250         if (WARN_ON(!p->cs_enabled))
 251                 return;
 252
 253         sh_tmu_disable(p);
 254         p->cs_enabled = false;
 255 }
 256
 257 static void sh_tmu_clocksource_suspend(struct clocksource *cs)
 258 {
 259         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 260
 261         if (!p->cs_enabled)
 262                 return;
 263
 264         if (--p->enable_count == 0) {
 265                 __sh_tmu_disable(p);
 266                 pm_genpd_syscore_poweroff(&p->pdev->dev);
 267         }
 268 }
 269
 270 static void sh_tmu_clocksource_resume(struct clocksource *cs)
 271 {
 272         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 273
 274         if (!p->cs_enabled)
 275                 return;
 276
 277         if (p->enable_count++ == 0) {
 278                 pm_genpd_syscore_poweron(&p->pdev->dev);
 279                 __sh_tmu_enable(p);
 280         }
 281 }
 282
 283 static int sh_tmu_register_clocksource(struct sh_tmu_priv *p,
 284                                        char *name, unsigned long rating)
 285 {
 286         struct clocksource *cs = &p->cs;
 287
 288         cs->name = name;
 289         cs->rating = rating;
 290         cs->read = sh_tmu_clocksource_read;
 291         cs->enable = sh_tmu_clocksource_enable;
 292         cs->disable = sh_tmu_clocksource_disable;
 293         cs->suspend = sh_tmu_clocksource_suspend;
 294         cs->resume = sh_tmu_clocksource_resume;
 295         cs->mask = CLOCKSOURCE_MASK(32);
 296         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
 297
 298         dev_info(&p->pdev->dev, "used as clock source\n");
 299
 300         /* Register with dummy 1 Hz value, gets updated in ->enable() */
 301         clocksource_register_hz(cs, 1);
 302         return 0;
 303 }
 304
 305 static struct sh_tmu_priv *ced_to_sh_tmu(struct clock_event_device *ced)
 306 {
 307         return container_of(ced, struct sh_tmu_priv, ced);
 308 }
 309
 310 static void sh_tmu_clock_event_start(struct sh_tmu_priv *p, int periodic)
 311 {
 312         struct clock_event_device *ced = &p->ced;
 313
 314         sh_tmu_enable(p);
 315
 316         clockevents_config(ced, p->rate);
 317
 318         if (periodic) {
 319                 p->periodic = (p->rate + HZ/2) / HZ;
 320                 sh_tmu_set_next(p, p->periodic, 1);
 321         }
 322 }
 323
 324 static void sh_tmu_clock_event_mode(enum clock_event_mode mode,
 325                                     struct clock_event_device *ced)
 326 {
 327         struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
 328         int disabled = 0;
 329
 330         /* deal with old setting first */
 331         switch (ced->mode) {
 332         case CLOCK_EVT_MODE_PERIODIC:
 333         case CLOCK_EVT_MODE_ONESHOT:
 334                 sh_tmu_disable(p);
 335                 disabled = 1;
 336                 break;
 337         default:
 338                 break;
 339         }
 340
 341         switch (mode) {
 342         case CLOCK_EVT_MODE_PERIODIC:
 343                 dev_info(&p->pdev->dev, "used for periodic clock events\n");
 344                 sh_tmu_clock_event_start(p, 1);
 345                 break;
 346         case CLOCK_EVT_MODE_ONESHOT:
 347                 dev_info(&p->pdev->dev, "used for oneshot clock events\n");
 348                 sh_tmu_clock_event_start(p, 0);
 349                 break;
 350         case CLOCK_EVT_MODE_UNUSED:
 351                 if (!disabled)
 352                         sh_tmu_disable(p);
 353                 break;
 354         case CLOCK_EVT_MODE_SHUTDOWN:
 355         default:
 356                 break;
 357         }
 358 }
 359
 360 static int sh_tmu_clock_event_next(unsigned long delta,
 361                                    struct clock_event_device *ced)
 362 {
 363         struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
 364
 365         BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
 366
 367         /* program new delta value */
 368         sh_tmu_set_next(p, delta, 0);
 369         return 0;
 370 }
 371
 372 static void sh_tmu_clock_event_suspend(struct clock_event_device *ced)
 373 {
 374         pm_genpd_syscore_poweroff(&ced_to_sh_tmu(ced)->pdev->dev);
 375 }
 376
 377 static void sh_tmu_clock_event_resume(struct clock_event_device *ced)
 378 {
 379         pm_genpd_syscore_poweron(&ced_to_sh_tmu(ced)->pdev->dev);
 380 }
 381
 382 static void sh_tmu_register_clockevent(struct sh_tmu_priv *p,
 383                                        char *name, unsigned long rating)
 384 {
 385         struct clock_event_device *ced = &p->ced;
 386         int ret;
 387
 388         memset(ced, 0, sizeof(*ced));
 389
 390         ced->name = name;
 391         ced->features = CLOCK_EVT_FEAT_PERIODIC;
 392         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
 393         ced->rating = rating;
 394         ced->cpumask = cpumask_of(0);
 395         ced->set_next_event = sh_tmu_clock_event_next;
 396         ced->set_mode = sh_tmu_clock_event_mode;
 397         ced->suspend = sh_tmu_clock_event_suspend;
 398         ced->resume = sh_tmu_clock_event_resume;
 399
 400         dev_info(&p->pdev->dev, "used for clock events\n");
 401
 402         clockevents_config_and_register(ced, 1, 0x300, 0xffffffff);
 403
 404         ret = setup_irq(p->irqaction.irq, &p->irqaction);
 405         if (ret) {
 406                 dev_err(&p->pdev->dev, "failed to request irq %d\n",
 407                         p->irqaction.irq);
 408                 return;
 409         }
 410 }
 411
 412 static int sh_tmu_register(struct sh_tmu_priv *p, char *name,
 413                     unsigned long clockevent_rating,
 414                     unsigned long clocksource_rating)
 415 {
 416         if (clockevent_rating)
 417                 sh_tmu_register_clockevent(p, name, clockevent_rating);
 418         else if (clocksource_rating)
 419                 sh_tmu_register_clocksource(p, name, clocksource_rating);
 420
 421         return 0;
 422 }
 423
 424 static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
 425 {
 426         struct sh_timer_config *cfg = pdev->dev.platform_data;
 427         struct resource *res;
 428         int irq, ret;
 429         ret = -ENXIO;
 430
 431         memset(p, 0, sizeof(*p));
 432         p->pdev = pdev;
 433
 434         if (!cfg) {
 435                 dev_err(&p->pdev->dev, "missing platform data\n");
 436                 goto err0;
 437         }
 438
 439         platform_set_drvdata(pdev, p);
 440
 441         res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
 442         if (!res) {
 443                 dev_err(&p->pdev->dev, "failed to get I/O memory\n");
 444                 goto err0;
 445         }
 446
 447         irq = platform_get_irq(p->pdev, 0);
 448         if (irq < 0) {
 449                 dev_err(&p->pdev->dev, "failed to get irq\n");
 450                 goto err0;
 451         }
 452
 453         /* map memory, let mapbase point to our channel */
 454         p->mapbase = ioremap_nocache(res->start, resource_size(res));
 455         if (p->mapbase == NULL) {
 456                 dev_err(&p->pdev->dev, "failed to remap I/O memory\n");
 457                 goto err0;
 458         }
 459
 460         /* setup data for setup_irq() (too early for request_irq()) */
 461         p->irqaction.name = dev_name(&p->pdev->dev);
 462         p->irqaction.handler = sh_tmu_interrupt;
 463         p->irqaction.dev_id = p;
 464         p->irqaction.irq = irq;
 465         p->irqaction.flags = IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING;
 466
 467         /* get hold of clock */
 468         p->clk = clk_get(&p->pdev->dev, "tmu_fck");
 469         if (IS_ERR(p->clk)) {
 470                 dev_err(&p->pdev->dev, "cannot get clock\n");
 471                 ret = PTR_ERR(p->clk);
 472                 goto err1;
 473         }
 474
 475         ret = clk_prepare(p->clk);
 476         if (ret < 0)
 477                 goto err2;
 478
 479         p->cs_enabled = false;
 480         p->enable_count = 0;
 481
 482         ret = sh_tmu_register(p, (char *)dev_name(&p->pdev->dev),
 483                               cfg->clockevent_rating,
 484                               cfg->clocksource_rating);
 485         if (ret < 0)
 486                 goto err3;
 487
 488         return 0;
 489
 490  err3:
 491         clk_unprepare(p->clk);
 492  err2:
 493         clk_put(p->clk);
 494  err1:
 495         iounmap(p->mapbase);
 496  err0:
 497         return ret;
 498 }
 499
 500 static int sh_tmu_probe(struct platform_device *pdev)
 501 {
 502         struct sh_tmu_priv *p = platform_get_drvdata(pdev);
 503         struct sh_timer_config *cfg = pdev->dev.platform_data;
 504         int ret;
 505
 506         if (!is_early_platform_device(pdev)) {
 507                 pm_runtime_set_active(&pdev->dev);
 508                 pm_runtime_enable(&pdev->dev);
 509         }
 510
 511         if (p) {
 512                 dev_info(&pdev->dev, "kept as earlytimer\n");
 513                 goto out;
 514         }
 515
 516         p = kmalloc(sizeof(*p), GFP_KERNEL);
 517         if (p == NULL) {
 518                 dev_err(&pdev->dev, "failed to allocate driver data\n");
 519                 return -ENOMEM;
 520         }
 521
 522         ret = sh_tmu_setup(p, pdev);
 523         if (ret) {
 524                 kfree(p);
 525                 pm_runtime_idle(&pdev->dev);
 526                 return ret;
 527         }
 528         if (is_early_platform_device(pdev))
 529                 return 0;
 530
 531  out:
 532         if (cfg->clockevent_rating || cfg->clocksource_rating)
 533                 pm_runtime_irq_safe(&pdev->dev);
 534         else
 535                 pm_runtime_idle(&pdev->dev);
 536
 537         return 0;
 538 }
 539
 540 static int sh_tmu_remove(struct platform_device *pdev)
 541 {
 542         return -EBUSY; /* cannot unregister clockevent and clocksource */
 543 }
 544
 545 static struct platform_driver sh_tmu_device_driver = {
 546         .probe          = sh_tmu_probe,
 547         .remove         = sh_tmu_remove,
 548         .driver         = {
 549                 .name   = "sh_tmu",
 550         }
 551 };
 552
 553 static int __init sh_tmu_init(void)
 554 {
 555         return platform_driver_register(&sh_tmu_device_driver);
 556 }
 557
 558 static void __exit sh_tmu_exit(void)
 559 {
 560         platform_driver_unregister(&sh_tmu_device_driver);
 561 }
 562
 563 early_platform_init("earlytimer", &sh_tmu_device_driver);
 564 subsys_initcall(sh_tmu_init);
 565 module_exit(sh_tmu_exit);
 566
 567 MODULE_AUTHOR("Magnus Damm");
 568 MODULE_DESCRIPTION("SuperH TMU Timer Driver");
 569 MODULE_LICENSE("GPL v2");