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