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
  37 struct sh_tmu_priv {
  38         void __iomem *mapbase;
  39         struct clk *clk;
  40         struct irqaction irqaction;
  41         struct platform_device *pdev;
  42         unsigned long rate;
  43         unsigned long periodic;
  44         struct clock_event_device ced;
  45         struct clocksource cs;
  46 };
  47
  48 static DEFINE_SPINLOCK(sh_tmu_lock);
  49
  50 #define TSTR -1 /* shared register */
  51 #define TCOR  0 /* channel register */
  52 #define TCNT 1 /* channel register */
  53 #define TCR 2 /* channel register */
  54
  55 static inline unsigned long sh_tmu_read(struct sh_tmu_priv *p, int reg_nr)
  56 {
  57         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  58         void __iomem *base = p->mapbase;
  59         unsigned long offs;
  60
  61         if (reg_nr == TSTR)
  62                 return ioread8(base - cfg->channel_offset);
  63
  64         offs = reg_nr << 2;
  65
  66         if (reg_nr == TCR)
  67                 return ioread16(base + offs);
  68         else
  69                 return ioread32(base + offs);
  70 }
  71
  72 static inline void sh_tmu_write(struct sh_tmu_priv *p, int reg_nr,
  73                                 unsigned long value)
  74 {
  75         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  76         void __iomem *base = p->mapbase;
  77         unsigned long offs;
  78
  79         if (reg_nr == TSTR) {
  80                 iowrite8(value, base - cfg->channel_offset);
  81                 return;
  82         }
  83
  84         offs = reg_nr << 2;
  85
  86         if (reg_nr == TCR)
  87                 iowrite16(value, base + offs);
  88         else
  89                 iowrite32(value, base + offs);
  90 }
  91
  92 static void sh_tmu_start_stop_ch(struct sh_tmu_priv *p, int start)
  93 {
  94         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  95         unsigned long flags, value;
  96
  97         /* start stop register shared by multiple timer channels */
  98         spin_lock_irqsave(&sh_tmu_lock, flags);
  99         value = sh_tmu_read(p, TSTR);
 100
 101         if (start)
 102                 value |= 1 << cfg->timer_bit;
 103         else
 104                 value &= ~(1 << cfg->timer_bit);
 105
 106         sh_tmu_write(p, TSTR, value);
 107         spin_unlock_irqrestore(&sh_tmu_lock, flags);
 108 }
 109
 110 static int sh_tmu_enable(struct sh_tmu_priv *p)
 111 {
 112         int ret;
 113
 114         /* enable clock */
 115         ret = clk_enable(p->clk);
 116         if (ret) {
 117                 dev_err(&p->pdev->dev, "cannot enable clock\n");
 118                 return ret;
 119         }
 120
 121         /* make sure channel is disabled */
 122         sh_tmu_start_stop_ch(p, 0);
 123
 124         /* maximum timeout */
 125         sh_tmu_write(p, TCOR, 0xffffffff);
 126         sh_tmu_write(p, TCNT, 0xffffffff);
 127
 128         /* configure channel to parent clock / 4, irq off */
 129         p->rate = clk_get_rate(p->clk) / 4;
 130         sh_tmu_write(p, TCR, 0x0000);
 131
 132         /* enable channel */
 133         sh_tmu_start_stop_ch(p, 1);
 134
 135         return 0;
 136 }
 137
 138 static void sh_tmu_disable(struct sh_tmu_priv *p)
 139 {
 140         /* disable channel */
 141         sh_tmu_start_stop_ch(p, 0);
 142
 143         /* disable interrupts in TMU block */
 144         sh_tmu_write(p, TCR, 0x0000);
 145
 146         /* stop clock */
 147         clk_disable(p->clk);
 148 }
 149
 150 static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
 151                             int periodic)
 152 {
 153         /* stop timer */
 154         sh_tmu_start_stop_ch(p, 0);
 155
 156         /* acknowledge interrupt */
 157         sh_tmu_read(p, TCR);
 158
 159         /* enable interrupt */
 160         sh_tmu_write(p, TCR, 0x0020);
 161
 162         /* reload delta value in case of periodic timer */
 163         if (periodic)
 164                 sh_tmu_write(p, TCOR, delta);
 165         else
 166                 sh_tmu_write(p, TCOR, 0xffffffff);
 167
 168         sh_tmu_write(p, TCNT, delta);
 169
 170         /* start timer */
 171         sh_tmu_start_stop_ch(p, 1);
 172 }
 173
 174 static irqreturn_t sh_tmu_interrupt(int irq, void *dev_id)
 175 {
 176         struct sh_tmu_priv *p = dev_id;
 177
 178         /* disable or acknowledge interrupt */
 179         if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT)
 180                 sh_tmu_write(p, TCR, 0x0000);
 181         else
 182                 sh_tmu_write(p, TCR, 0x0020);
 183
 184         /* notify clockevent layer */
 185         p->ced.event_handler(&p->ced);
 186         return IRQ_HANDLED;
 187 }
 188
 189 static struct sh_tmu_priv *cs_to_sh_tmu(struct clocksource *cs)
 190 {
 191         return container_of(cs, struct sh_tmu_priv, cs);
 192 }
 193
 194 static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
 195 {
 196         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 197
 198         return sh_tmu_read(p, TCNT) ^ 0xffffffff;
 199 }
 200
 201 static int sh_tmu_clocksource_enable(struct clocksource *cs)
 202 {
 203         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 204         int ret;
 205
 206         ret = sh_tmu_enable(p);
 207         if (!ret)
 208                 __clocksource_updatefreq_hz(cs, p->rate);
 209         return ret;
 210 }
 211
 212 static void sh_tmu_clocksource_disable(struct clocksource *cs)
 213 {
 214         sh_tmu_disable(cs_to_sh_tmu(cs));
 215 }
 216
 217 static int sh_tmu_register_clocksource(struct sh_tmu_priv *p,
 218                                        char *name, unsigned long rating)
 219 {
 220         struct clocksource *cs = &p->cs;
 221
 222         cs->name = name;
 223         cs->rating = rating;
 224         cs->read = sh_tmu_clocksource_read;
 225         cs->enable = sh_tmu_clocksource_enable;
 226         cs->disable = sh_tmu_clocksource_disable;
 227         cs->mask = CLOCKSOURCE_MASK(32);
 228         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
 229
 230         dev_info(&p->pdev->dev, "used as clock source\n");
 231
 232         /* Register with dummy 1 Hz value, gets updated in ->enable() */
 233         clocksource_register_hz(cs, 1);
 234         return 0;
 235 }
 236
 237 static struct sh_tmu_priv *ced_to_sh_tmu(struct clock_event_device *ced)
 238 {
 239         return container_of(ced, struct sh_tmu_priv, ced);
 240 }
 241
 242 static void sh_tmu_clock_event_start(struct sh_tmu_priv *p, int periodic)
 243 {
 244         struct clock_event_device *ced = &p->ced;
 245
 246         sh_tmu_enable(p);
 247
 248         /* TODO: calculate good shift from rate and counter bit width */
 249
 250         ced->shift = 32;
 251         ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
 252         ced->max_delta_ns = clockevent_delta2ns(0xffffffff, ced);
 253         ced->min_delta_ns = 5000;
 254
 255         if (periodic) {
 256                 p->periodic = (p->rate + HZ/2) / HZ;
 257                 sh_tmu_set_next(p, p->periodic, 1);
 258         }
 259 }
 260
 261 static void sh_tmu_clock_event_mode(enum clock_event_mode mode,
 262                                     struct clock_event_device *ced)
 263 {
 264         struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
 265         int disabled = 0;
 266
 267         /* deal with old setting first */
 268         switch (ced->mode) {
 269         case CLOCK_EVT_MODE_PERIODIC:
 270         case CLOCK_EVT_MODE_ONESHOT:
 271                 sh_tmu_disable(p);
 272                 disabled = 1;
 273                 break;
 274         default:
 275                 break;
 276         }
 277
 278         switch (mode) {
 279         case CLOCK_EVT_MODE_PERIODIC:
 280                 dev_info(&p->pdev->dev, "used for periodic clock events\n");
 281                 sh_tmu_clock_event_start(p, 1);
 282                 break;
 283         case CLOCK_EVT_MODE_ONESHOT:
 284                 dev_info(&p->pdev->dev, "used for oneshot clock events\n");
 285                 sh_tmu_clock_event_start(p, 0);
 286                 break;
 287         case CLOCK_EVT_MODE_UNUSED:
 288                 if (!disabled)
 289                         sh_tmu_disable(p);
 290                 break;
 291         case CLOCK_EVT_MODE_SHUTDOWN:
 292         default:
 293                 break;
 294         }
 295 }
 296
 297 static int sh_tmu_clock_event_next(unsigned long delta,
 298                                    struct clock_event_device *ced)
 299 {
 300         struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
 301
 302         BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
 303
 304         /* program new delta value */
 305         sh_tmu_set_next(p, delta, 0);
 306         return 0;
 307 }
 308
 309 static void sh_tmu_register_clockevent(struct sh_tmu_priv *p,
 310                                        char *name, unsigned long rating)
 311 {
 312         struct clock_event_device *ced = &p->ced;
 313         int ret;
 314
 315         memset(ced, 0, sizeof(*ced));
 316
 317         ced->name = name;
 318         ced->features = CLOCK_EVT_FEAT_PERIODIC;
 319         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
 320         ced->rating = rating;
 321         ced->cpumask = cpumask_of(0);
 322         ced->set_next_event = sh_tmu_clock_event_next;
 323         ced->set_mode = sh_tmu_clock_event_mode;
 324
 325         dev_info(&p->pdev->dev, "used for clock events\n");
 326         clockevents_register_device(ced);
 327
 328         ret = setup_irq(p->irqaction.irq, &p->irqaction);
 329         if (ret) {
 330                 dev_err(&p->pdev->dev, "failed to request irq %d\n",
 331                         p->irqaction.irq);
 332                 return;
 333         }
 334 }
 335
 336 static int sh_tmu_register(struct sh_tmu_priv *p, char *name,
 337                     unsigned long clockevent_rating,
 338                     unsigned long clocksource_rating)
 339 {
 340         if (clockevent_rating)
 341                 sh_tmu_register_clockevent(p, name, clockevent_rating);
 342         else if (clocksource_rating)
 343                 sh_tmu_register_clocksource(p, name, clocksource_rating);
 344
 345         return 0;
 346 }
 347
 348 static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
 349 {
 350         struct sh_timer_config *cfg = pdev->dev.platform_data;
 351         struct resource *res;
 352         int irq, ret;
 353         ret = -ENXIO;
 354
 355         memset(p, 0, sizeof(*p));
 356         p->pdev = pdev;
 357
 358         if (!cfg) {
 359                 dev_err(&p->pdev->dev, "missing platform data\n");
 360                 goto err0;
 361         }
 362
 363         platform_set_drvdata(pdev, p);
 364
 365         res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
 366         if (!res) {
 367                 dev_err(&p->pdev->dev, "failed to get I/O memory\n");
 368                 goto err0;
 369         }
 370
 371         irq = platform_get_irq(p->pdev, 0);
 372         if (irq < 0) {
 373                 dev_err(&p->pdev->dev, "failed to get irq\n");
 374                 goto err0;
 375         }
 376
 377         /* map memory, let mapbase point to our channel */
 378         p->mapbase = ioremap_nocache(res->start, resource_size(res));
 379         if (p->mapbase == NULL) {
 380                 dev_err(&p->pdev->dev, "failed to remap I/O memory\n");
 381                 goto err0;
 382         }
 383
 384         /* setup data for setup_irq() (too early for request_irq()) */
 385         p->irqaction.name = dev_name(&p->pdev->dev);
 386         p->irqaction.handler = sh_tmu_interrupt;
 387         p->irqaction.dev_id = p;
 388         p->irqaction.irq = irq;
 389         p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | \
 390                              IRQF_IRQPOLL  | IRQF_NOBALANCING;
 391
 392         /* get hold of clock */
 393         p->clk = clk_get(&p->pdev->dev, "tmu_fck");
 394         if (IS_ERR(p->clk)) {
 395                 dev_err(&p->pdev->dev, "cannot get clock\n");
 396                 ret = PTR_ERR(p->clk);
 397                 goto err1;
 398         }
 399
 400         return sh_tmu_register(p, (char *)dev_name(&p->pdev->dev),
 401                                cfg->clockevent_rating,
 402                                cfg->clocksource_rating);
 403  err1:
 404         iounmap(p->mapbase);
 405  err0:
 406         return ret;
 407 }
 408
 409 static int __devinit sh_tmu_probe(struct platform_device *pdev)
 410 {
 411         struct sh_tmu_priv *p = platform_get_drvdata(pdev);
 412         int ret;
 413
 414         if (!is_early_platform_device(pdev))
 415                 pm_genpd_dev_always_on(&pdev->dev, true);
 416
 417         if (p) {
 418                 dev_info(&pdev->dev, "kept as earlytimer\n");
 419                 return 0;
 420         }
 421
 422         p = kmalloc(sizeof(*p), GFP_KERNEL);
 423         if (p == NULL) {
 424                 dev_err(&pdev->dev, "failed to allocate driver data\n");
 425                 return -ENOMEM;
 426         }
 427
 428         ret = sh_tmu_setup(p, pdev);
 429         if (ret) {
 430                 kfree(p);
 431                 platform_set_drvdata(pdev, NULL);
 432         }
 433         return ret;
 434 }
 435
 436 static int __devexit sh_tmu_remove(struct platform_device *pdev)
 437 {
 438         return -EBUSY; /* cannot unregister clockevent and clocksource */
 439 }
 440
 441 static struct platform_driver sh_tmu_device_driver = {
 442         .probe          = sh_tmu_probe,
 443         .remove         = __devexit_p(sh_tmu_remove),
 444         .driver         = {
 445                 .name   = "sh_tmu",
 446         }
 447 };
 448
 449 static int __init sh_tmu_init(void)
 450 {
 451         return platform_driver_register(&sh_tmu_device_driver);
 452 }
 453
 454 static void __exit sh_tmu_exit(void)
 455 {
 456         platform_driver_unregister(&sh_tmu_device_driver);
 457 }
 458
 459 early_platform_init("earlytimer", &sh_tmu_device_driver);
 460 module_init(sh_tmu_init);
 461 module_exit(sh_tmu_exit);
 462
 463 MODULE_AUTHOR("Magnus Damm");
 464 MODULE_DESCRIPTION("SuperH TMU Timer Driver");
 465 MODULE_LICENSE("GPL v2");