drivers/clocksource/sh_cmt.c

   1 /*
   2  * SuperH Timer Support - CMT
   3  *
   4  *  Copyright (C) 2008 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/io.h>
  26 #include <linux/clk.h>
  27 #include <linux/irq.h>
  28 #include <linux/err.h>
  29 #include <linux/clocksource.h>
  30 #include <linux/clockchips.h>
  31 #include <linux/sh_timer.h>
  32 #include <linux/slab.h>
  33
  34 struct sh_cmt_priv {
  35         void __iomem *mapbase;
  36         struct clk *clk;
  37         unsigned long width; /* 16 or 32 bit version of hardware block */
  38         unsigned long overflow_bit;
  39         unsigned long clear_bits;
  40         struct irqaction irqaction;
  41         struct platform_device *pdev;
  42
  43         unsigned long flags;
  44         unsigned long match_value;
  45         unsigned long next_match_value;
  46         unsigned long max_match_value;
  47         unsigned long rate;
  48         spinlock_t lock;
  49         struct clock_event_device ced;
  50         struct clocksource cs;
  51         unsigned long total_cycles;
  52 };
  53
  54 static DEFINE_SPINLOCK(sh_cmt_lock);
  55
  56 #define CMSTR -1 /* shared register */
  57 #define CMCSR 0 /* channel register */
  58 #define CMCNT 1 /* channel register */
  59 #define CMCOR 2 /* channel register */
  60
  61 static inline unsigned long sh_cmt_read(struct sh_cmt_priv *p, int reg_nr)
  62 {
  63         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  64         void __iomem *base = p->mapbase;
  65         unsigned long offs;
  66
  67         if (reg_nr == CMSTR) {
  68                 offs = 0;
  69                 base -= cfg->channel_offset;
  70         } else
  71                 offs = reg_nr;
  72
  73         if (p->width == 16)
  74                 offs <<= 1;
  75         else {
  76                 offs <<= 2;
  77                 if ((reg_nr == CMCNT) || (reg_nr == CMCOR))
  78                         return ioread32(base + offs);
  79         }
  80
  81         return ioread16(base + offs);
  82 }
  83
  84 static inline void sh_cmt_write(struct sh_cmt_priv *p, int reg_nr,
  85                                 unsigned long value)
  86 {
  87         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  88         void __iomem *base = p->mapbase;
  89         unsigned long offs;
  90
  91         if (reg_nr == CMSTR) {
  92                 offs = 0;
  93                 base -= cfg->channel_offset;
  94         } else
  95                 offs = reg_nr;
  96
  97         if (p->width == 16)
  98                 offs <<= 1;
  99         else {
 100                 offs <<= 2;
 101                 if ((reg_nr == CMCNT) || (reg_nr == CMCOR)) {
 102                         iowrite32(value, base + offs);
 103                         return;
 104                 }
 105         }
 106
 107         iowrite16(value, base + offs);
 108 }
 109
 110 static unsigned long sh_cmt_get_counter(struct sh_cmt_priv *p,
 111                                         int *has_wrapped)
 112 {
 113         unsigned long v1, v2, v3;
 114         int o1, o2;
 115
 116         o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
 117
 118         /* Make sure the timer value is stable. Stolen from acpi_pm.c */
 119         do {
 120                 o2 = o1;
 121                 v1 = sh_cmt_read(p, CMCNT);
 122                 v2 = sh_cmt_read(p, CMCNT);
 123                 v3 = sh_cmt_read(p, CMCNT);
 124                 o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
 125         } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
 126                           || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
 127
 128         *has_wrapped = o1;
 129         return v2;
 130 }
 131
 132
 133 static void sh_cmt_start_stop_ch(struct sh_cmt_priv *p, int start)
 134 {
 135         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
 136         unsigned long flags, value;
 137
 138         /* start stop register shared by multiple timer channels */
 139         spin_lock_irqsave(&sh_cmt_lock, flags);
 140         value = sh_cmt_read(p, CMSTR);
 141
 142         if (start)
 143                 value |= 1 << cfg->timer_bit;
 144         else
 145                 value &= ~(1 << cfg->timer_bit);
 146
 147         sh_cmt_write(p, CMSTR, value);
 148         spin_unlock_irqrestore(&sh_cmt_lock, flags);
 149 }
 150
 151 static int sh_cmt_enable(struct sh_cmt_priv *p, unsigned long *rate)
 152 {
 153         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
 154         int ret;
 155
 156         /* enable clock */
 157         ret = clk_enable(p->clk);
 158         if (ret) {
 159                 pr_err("sh_cmt: cannot enable clock \"%s\"\n", cfg->clk);
 160                 return ret;
 161         }
 162
 163         /* make sure channel is disabled */
 164         sh_cmt_start_stop_ch(p, 0);
 165
 166         /* configure channel, periodic mode and maximum timeout */
 167         if (p->width == 16) {
 168                 *rate = clk_get_rate(p->clk) / 512;
 169                 sh_cmt_write(p, CMCSR, 0x43);
 170         } else {
 171                 *rate = clk_get_rate(p->clk) / 8;
 172                 sh_cmt_write(p, CMCSR, 0x01a4);
 173         }
 174
 175         sh_cmt_write(p, CMCOR, 0xffffffff);
 176         sh_cmt_write(p, CMCNT, 0);
 177
 178         /* enable channel */
 179         sh_cmt_start_stop_ch(p, 1);
 180         return 0;
 181 }
 182
 183 static void sh_cmt_disable(struct sh_cmt_priv *p)
 184 {
 185         /* disable channel */
 186         sh_cmt_start_stop_ch(p, 0);
 187
 188         /* disable interrupts in CMT block */
 189         sh_cmt_write(p, CMCSR, 0);
 190
 191         /* stop clock */
 192         clk_disable(p->clk);
 193 }
 194
 195 /* private flags */
 196 #define FLAG_CLOCKEVENT (1 << 0)
 197 #define FLAG_CLOCKSOURCE (1 << 1)
 198 #define FLAG_REPROGRAM (1 << 2)
 199 #define FLAG_SKIPEVENT (1 << 3)
 200 #define FLAG_IRQCONTEXT (1 << 4)
 201
 202 static void sh_cmt_clock_event_program_verify(struct sh_cmt_priv *p,
 203                                               int absolute)
 204 {
 205         unsigned long new_match;
 206         unsigned long value = p->next_match_value;
 207         unsigned long delay = 0;
 208         unsigned long now = 0;
 209         int has_wrapped;
 210
 211         now = sh_cmt_get_counter(p, &has_wrapped);
 212         p->flags |= FLAG_REPROGRAM; /* force reprogram */
 213
 214         if (has_wrapped) {
 215                 /* we're competing with the interrupt handler.
 216                  *  -> let the interrupt handler reprogram the timer.
 217                  *  -> interrupt number two handles the event.
 218                  */
 219                 p->flags |= FLAG_SKIPEVENT;
 220                 return;
 221         }
 222
 223         if (absolute)
 224                 now = 0;
 225
 226         do {
 227                 /* reprogram the timer hardware,
 228                  * but don't save the new match value yet.
 229                  */
 230                 new_match = now + value + delay;
 231                 if (new_match > p->max_match_value)
 232                         new_match = p->max_match_value;
 233
 234                 sh_cmt_write(p, CMCOR, new_match);
 235
 236                 now = sh_cmt_get_counter(p, &has_wrapped);
 237                 if (has_wrapped && (new_match > p->match_value)) {
 238                         /* we are changing to a greater match value,
 239                          * so this wrap must be caused by the counter
 240                          * matching the old value.
 241                          * -> first interrupt reprograms the timer.
 242                          * -> interrupt number two handles the event.
 243                          */
 244                         p->flags |= FLAG_SKIPEVENT;
 245                         break;
 246                 }
 247
 248                 if (has_wrapped) {
 249                         /* we are changing to a smaller match value,
 250                          * so the wrap must be caused by the counter
 251                          * matching the new value.
 252                          * -> save programmed match value.
 253                          * -> let isr handle the event.
 254                          */
 255                         p->match_value = new_match;
 256                         break;
 257                 }
 258
 259                 /* be safe: verify hardware settings */
 260                 if (now < new_match) {
 261                         /* timer value is below match value, all good.
 262                          * this makes sure we won't miss any match events.
 263                          * -> save programmed match value.
 264                          * -> let isr handle the event.
 265                          */
 266                         p->match_value = new_match;
 267                         break;
 268                 }
 269
 270                 /* the counter has reached a value greater
 271                  * than our new match value. and since the
 272                  * has_wrapped flag isn't set we must have
 273                  * programmed a too close event.
 274                  * -> increase delay and retry.
 275                  */
 276                 if (delay)
 277                         delay <<= 1;
 278                 else
 279                         delay = 1;
 280
 281                 if (!delay)
 282                         pr_warning("sh_cmt: too long delay\n");
 283
 284         } while (delay);
 285 }
 286
 287 static void sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)
 288 {
 289         unsigned long flags;
 290
 291         if (delta > p->max_match_value)
 292                 pr_warning("sh_cmt: delta out of range\n");
 293
 294         spin_lock_irqsave(&p->lock, flags);
 295         p->next_match_value = delta;
 296         sh_cmt_clock_event_program_verify(p, 0);
 297         spin_unlock_irqrestore(&p->lock, flags);
 298 }
 299
 300 static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
 301 {
 302         struct sh_cmt_priv *p = dev_id;
 303
 304         /* clear flags */
 305         sh_cmt_write(p, CMCSR, sh_cmt_read(p, CMCSR) & p->clear_bits);
 306
 307         /* update clock source counter to begin with if enabled
 308          * the wrap flag should be cleared by the timer specific
 309          * isr before we end up here.
 310          */
 311         if (p->flags & FLAG_CLOCKSOURCE)
 312                 p->total_cycles += p->match_value;
 313
 314         if (!(p->flags & FLAG_REPROGRAM))
 315                 p->next_match_value = p->max_match_value;
 316
 317         p->flags |= FLAG_IRQCONTEXT;
 318
 319         if (p->flags & FLAG_CLOCKEVENT) {
 320                 if (!(p->flags & FLAG_SKIPEVENT)) {
 321                         if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT) {
 322                                 p->next_match_value = p->max_match_value;
 323                                 p->flags |= FLAG_REPROGRAM;
 324                         }
 325
 326                         p->ced.event_handler(&p->ced);
 327                 }
 328         }
 329
 330         p->flags &= ~FLAG_SKIPEVENT;
 331
 332         if (p->flags & FLAG_REPROGRAM) {
 333                 p->flags &= ~FLAG_REPROGRAM;
 334                 sh_cmt_clock_event_program_verify(p, 1);
 335
 336                 if (p->flags & FLAG_CLOCKEVENT)
 337                         if ((p->ced.mode == CLOCK_EVT_MODE_SHUTDOWN)
 338                             || (p->match_value == p->next_match_value))
 339                                 p->flags &= ~FLAG_REPROGRAM;
 340         }
 341
 342         p->flags &= ~FLAG_IRQCONTEXT;
 343
 344         return IRQ_HANDLED;
 345 }
 346
 347 static int sh_cmt_start(struct sh_cmt_priv *p, unsigned long flag)
 348 {
 349         int ret = 0;
 350         unsigned long flags;
 351
 352         spin_lock_irqsave(&p->lock, flags);
 353
 354         if (!(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
 355                 ret = sh_cmt_enable(p, &p->rate);
 356
 357         if (ret)
 358                 goto out;
 359         p->flags |= flag;
 360
 361         /* setup timeout if no clockevent */
 362         if ((flag == FLAG_CLOCKSOURCE) && (!(p->flags & FLAG_CLOCKEVENT)))
 363                 sh_cmt_set_next(p, p->max_match_value);
 364  out:
 365         spin_unlock_irqrestore(&p->lock, flags);
 366
 367         return ret;
 368 }
 369
 370 static void sh_cmt_stop(struct sh_cmt_priv *p, unsigned long flag)
 371 {
 372         unsigned long flags;
 373         unsigned long f;
 374
 375         spin_lock_irqsave(&p->lock, flags);
 376
 377         f = p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
 378         p->flags &= ~flag;
 379
 380         if (f && !(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
 381                 sh_cmt_disable(p);
 382
 383         /* adjust the timeout to maximum if only clocksource left */
 384         if ((flag == FLAG_CLOCKEVENT) && (p->flags & FLAG_CLOCKSOURCE))
 385                 sh_cmt_set_next(p, p->max_match_value);
 386
 387         spin_unlock_irqrestore(&p->lock, flags);
 388 }
 389
 390 static struct sh_cmt_priv *cs_to_sh_cmt(struct clocksource *cs)
 391 {
 392         return container_of(cs, struct sh_cmt_priv, cs);
 393 }
 394
 395 static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
 396 {
 397         struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
 398         unsigned long flags, raw;
 399         unsigned long value;
 400         int has_wrapped;
 401
 402         spin_lock_irqsave(&p->lock, flags);
 403         value = p->total_cycles;
 404         raw = sh_cmt_get_counter(p, &has_wrapped);
 405
 406         if (unlikely(has_wrapped))
 407                 raw += p->match_value;
 408         spin_unlock_irqrestore(&p->lock, flags);
 409
 410         return value + raw;
 411 }
 412
 413 static int sh_cmt_clocksource_enable(struct clocksource *cs)
 414 {
 415         struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
 416
 417         p->total_cycles = 0;
 418
 419         return sh_cmt_start(p, FLAG_CLOCKSOURCE);
 420 }
 421
 422 static void sh_cmt_clocksource_disable(struct clocksource *cs)
 423 {
 424         sh_cmt_stop(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
 425 }
 426
 427 static void sh_cmt_clocksource_resume(struct clocksource *cs)
 428 {
 429         sh_cmt_start(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
 430 }
 431
 432 static int sh_cmt_register_clocksource(struct sh_cmt_priv *p,
 433                                        char *name, unsigned long rating)
 434 {
 435         struct clocksource *cs = &p->cs;
 436
 437         cs->name = name;
 438         cs->rating = rating;
 439         cs->read = sh_cmt_clocksource_read;
 440         cs->enable = sh_cmt_clocksource_enable;
 441         cs->disable = sh_cmt_clocksource_disable;
 442         cs->suspend = sh_cmt_clocksource_disable;
 443         cs->resume = sh_cmt_clocksource_resume;
 444         cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
 445         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
 446
 447         /* clk_get_rate() needs an enabled clock */
 448         clk_enable(p->clk);
 449         p->rate = clk_get_rate(p->clk) / (p->width == 16) ? 512 : 8;
 450         clk_disable(p->clk);
 451
 452         /* TODO: calculate good shift from rate and counter bit width */
 453         cs->shift = 10;
 454         cs->mult = clocksource_hz2mult(p->rate, cs->shift);
 455
 456         pr_info("sh_cmt: %s used as clock source\n", cs->name);
 457
 458         clocksource_register(cs);
 459         return 0;
 460 }
 461
 462 static struct sh_cmt_priv *ced_to_sh_cmt(struct clock_event_device *ced)
 463 {
 464         return container_of(ced, struct sh_cmt_priv, ced);
 465 }
 466
 467 static void sh_cmt_clock_event_start(struct sh_cmt_priv *p, int periodic)
 468 {
 469         struct clock_event_device *ced = &p->ced;
 470
 471         sh_cmt_start(p, FLAG_CLOCKEVENT);
 472
 473         /* TODO: calculate good shift from rate and counter bit width */
 474
 475         ced->shift = 32;
 476         ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
 477         ced->max_delta_ns = clockevent_delta2ns(p->max_match_value, ced);
 478         ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
 479
 480         if (periodic)
 481                 sh_cmt_set_next(p, (p->rate + HZ/2) / HZ);
 482         else
 483                 sh_cmt_set_next(p, p->max_match_value);
 484 }
 485
 486 static void sh_cmt_clock_event_mode(enum clock_event_mode mode,
 487                                     struct clock_event_device *ced)
 488 {
 489         struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
 490
 491         /* deal with old setting first */
 492         switch (ced->mode) {
 493         case CLOCK_EVT_MODE_PERIODIC:
 494         case CLOCK_EVT_MODE_ONESHOT:
 495                 sh_cmt_stop(p, FLAG_CLOCKEVENT);
 496                 break;
 497         default:
 498                 break;
 499         }
 500
 501         switch (mode) {
 502         case CLOCK_EVT_MODE_PERIODIC:
 503                 pr_info("sh_cmt: %s used for periodic clock events\n",
 504                         ced->name);
 505                 sh_cmt_clock_event_start(p, 1);
 506                 break;
 507         case CLOCK_EVT_MODE_ONESHOT:
 508                 pr_info("sh_cmt: %s used for oneshot clock events\n",
 509                         ced->name);
 510                 sh_cmt_clock_event_start(p, 0);
 511                 break;
 512         case CLOCK_EVT_MODE_SHUTDOWN:
 513         case CLOCK_EVT_MODE_UNUSED:
 514                 sh_cmt_stop(p, FLAG_CLOCKEVENT);
 515                 break;
 516         default:
 517                 break;
 518         }
 519 }
 520
 521 static int sh_cmt_clock_event_next(unsigned long delta,
 522                                    struct clock_event_device *ced)
 523 {
 524         struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
 525
 526         BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
 527         if (likely(p->flags & FLAG_IRQCONTEXT))
 528                 p->next_match_value = delta;
 529         else
 530                 sh_cmt_set_next(p, delta);
 531
 532         return 0;
 533 }
 534
 535 static void sh_cmt_register_clockevent(struct sh_cmt_priv *p,
 536                                        char *name, unsigned long rating)
 537 {
 538         struct clock_event_device *ced = &p->ced;
 539
 540         memset(ced, 0, sizeof(*ced));
 541
 542         ced->name = name;
 543         ced->features = CLOCK_EVT_FEAT_PERIODIC;
 544         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
 545         ced->rating = rating;
 546         ced->cpumask = cpumask_of(0);
 547         ced->set_next_event = sh_cmt_clock_event_next;
 548         ced->set_mode = sh_cmt_clock_event_mode;
 549
 550         pr_info("sh_cmt: %s used for clock events\n", ced->name);
 551         clockevents_register_device(ced);
 552 }
 553
 554 static int sh_cmt_register(struct sh_cmt_priv *p, char *name,
 555                            unsigned long clockevent_rating,
 556                            unsigned long clocksource_rating)
 557 {
 558         if (p->width == (sizeof(p->max_match_value) * 8))
 559                 p->max_match_value = ~0;
 560         else
 561                 p->max_match_value = (1 << p->width) - 1;
 562
 563         p->match_value = p->max_match_value;
 564         spin_lock_init(&p->lock);
 565
 566         if (clockevent_rating)
 567                 sh_cmt_register_clockevent(p, name, clockevent_rating);
 568
 569         if (clocksource_rating)
 570                 sh_cmt_register_clocksource(p, name, clocksource_rating);
 571
 572         return 0;
 573 }
 574
 575 static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
 576 {
 577         struct sh_timer_config *cfg = pdev->dev.platform_data;
 578         struct resource *res;
 579         int irq, ret;
 580         ret = -ENXIO;
 581
 582         memset(p, 0, sizeof(*p));
 583         p->pdev = pdev;
 584
 585         if (!cfg) {
 586                 dev_err(&p->pdev->dev, "missing platform data\n");
 587                 goto err0;
 588         }
 589
 590         platform_set_drvdata(pdev, p);
 591
 592         res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
 593         if (!res) {
 594                 dev_err(&p->pdev->dev, "failed to get I/O memory\n");
 595                 goto err0;
 596         }
 597
 598         irq = platform_get_irq(p->pdev, 0);
 599         if (irq < 0) {
 600                 dev_err(&p->pdev->dev, "failed to get irq\n");
 601                 goto err0;
 602         }
 603
 604         /* map memory, let mapbase point to our channel */
 605         p->mapbase = ioremap_nocache(res->start, resource_size(res));
 606         if (p->mapbase == NULL) {
 607                 pr_err("sh_cmt: failed to remap I/O memory\n");
 608                 goto err0;
 609         }
 610
 611         /* request irq using setup_irq() (too early for request_irq()) */
 612         p->irqaction.name = cfg->name;
 613         p->irqaction.handler = sh_cmt_interrupt;
 614         p->irqaction.dev_id = p;
 615         p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL;
 616
 617         /* get hold of clock */
 618         p->clk = clk_get(&p->pdev->dev, cfg->clk);
 619         if (IS_ERR(p->clk)) {
 620                 pr_err("sh_cmt: cannot get clock \"%s\"\n", cfg->clk);
 621                 ret = PTR_ERR(p->clk);
 622                 goto err1;
 623         }
 624
 625         if (resource_size(res) == 6) {
 626                 p->width = 16;
 627                 p->overflow_bit = 0x80;
 628                 p->clear_bits = ~0x80;
 629         } else {
 630                 p->width = 32;
 631                 p->overflow_bit = 0x8000;
 632                 p->clear_bits = ~0xc000;
 633         }
 634
 635         ret = sh_cmt_register(p, cfg->name,
 636                               cfg->clockevent_rating,
 637                               cfg->clocksource_rating);
 638         if (ret) {
 639                 pr_err("sh_cmt: registration failed\n");
 640                 goto err1;
 641         }
 642
 643         ret = setup_irq(irq, &p->irqaction);
 644         if (ret) {
 645                 pr_err("sh_cmt: failed to request irq %d\n", irq);
 646                 goto err1;
 647         }
 648
 649         return 0;
 650
 651 err1:
 652         iounmap(p->mapbase);
 653 err0:
 654         return ret;
 655 }
 656
 657 static int __devinit sh_cmt_probe(struct platform_device *pdev)
 658 {
 659         struct sh_cmt_priv *p = platform_get_drvdata(pdev);
 660         struct sh_timer_config *cfg = pdev->dev.platform_data;
 661         int ret;
 662
 663         if (p) {
 664                 pr_info("sh_cmt: %s kept as earlytimer\n", cfg->name);
 665                 return 0;
 666         }
 667
 668         p = kmalloc(sizeof(*p), GFP_KERNEL);
 669         if (p == NULL) {
 670                 dev_err(&pdev->dev, "failed to allocate driver data\n");
 671                 return -ENOMEM;
 672         }
 673
 674         ret = sh_cmt_setup(p, pdev);
 675         if (ret) {
 676                 kfree(p);
 677                 platform_set_drvdata(pdev, NULL);
 678         }
 679         return ret;
 680 }
 681
 682 static int __devexit sh_cmt_remove(struct platform_device *pdev)
 683 {
 684         return -EBUSY; /* cannot unregister clockevent and clocksource */
 685 }
 686
 687 static struct platform_driver sh_cmt_device_driver = {
 688         .probe          = sh_cmt_probe,
 689         .remove         = __devexit_p(sh_cmt_remove),
 690         .driver         = {
 691                 .name   = "sh_cmt",
 692         }
 693 };
 694
 695 static int __init sh_cmt_init(void)
 696 {
 697         return platform_driver_register(&sh_cmt_device_driver);
 698 }
 699
 700 static void __exit sh_cmt_exit(void)
 701 {
 702         platform_driver_unregister(&sh_cmt_device_driver);
 703 }
 704
 705 early_platform_init("earlytimer", &sh_cmt_device_driver);
 706 module_init(sh_cmt_init);
 707 module_exit(sh_cmt_exit);
 708
 709 MODULE_AUTHOR("Magnus Damm");
 710 MODULE_DESCRIPTION("SuperH CMT Timer Driver");
 711 MODULE_LICENSE("GPL v2");