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
  34 struct sh_tmu_priv {
  35         void __iomem *mapbase;
  36         struct clk *clk;
  37         struct irqaction irqaction;
  38         struct platform_device *pdev;
  39         unsigned long rate;
  40         unsigned long periodic;
  41         struct clock_event_device ced;
  42         struct clocksource cs;
  43 };
  44
  45 static DEFINE_SPINLOCK(sh_tmu_lock);
  46
  47 #define TSTR -1 /* shared register */
  48 #define TCOR  0 /* channel register */
  49 #define TCNT 1 /* channel register */
  50 #define TCR 2 /* channel register */
  51
  52 static inline unsigned long sh_tmu_read(struct sh_tmu_priv *p, int reg_nr)
  53 {
  54         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  55         void __iomem *base = p->mapbase;
  56         unsigned long offs;
  57
  58         if (reg_nr == TSTR)
  59                 return ioread8(base - cfg->channel_offset);
  60
  61         offs = reg_nr << 2;
  62
  63         if (reg_nr == TCR)
  64                 return ioread16(base + offs);
  65         else
  66                 return ioread32(base + offs);
  67 }
  68
  69 static inline void sh_tmu_write(struct sh_tmu_priv *p, int reg_nr,
  70                                 unsigned long value)
  71 {
  72         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  73         void __iomem *base = p->mapbase;
  74         unsigned long offs;
  75
  76         if (reg_nr == TSTR) {
  77                 iowrite8(value, base - cfg->channel_offset);
  78                 return;
  79         }
  80
  81         offs = reg_nr << 2;
  82
  83         if (reg_nr == TCR)
  84                 iowrite16(value, base + offs);
  85         else
  86                 iowrite32(value, base + offs);
  87 }
  88
  89 static void sh_tmu_start_stop_ch(struct sh_tmu_priv *p, int start)
  90 {
  91         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  92         unsigned long flags, value;
  93
  94         /* start stop register shared by multiple timer channels */
  95         spin_lock_irqsave(&sh_tmu_lock, flags);
  96         value = sh_tmu_read(p, TSTR);
  97
  98         if (start)
  99                 value |= 1 << cfg->timer_bit;
 100         else
 101                 value &= ~(1 << cfg->timer_bit);
 102
 103         sh_tmu_write(p, TSTR, value);
 104         spin_unlock_irqrestore(&sh_tmu_lock, flags);
 105 }
 106
 107 static int sh_tmu_enable(struct sh_tmu_priv *p)
 108 {
 109         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
 110         int ret;
 111
 112         /* enable clock */
 113         ret = clk_enable(p->clk);
 114         if (ret) {
 115                 pr_err("sh_tmu: cannot enable clock \"%s\"\n", cfg->clk);
 116                 return ret;
 117         }
 118
 119         /* make sure channel is disabled */
 120         sh_tmu_start_stop_ch(p, 0);
 121
 122         /* maximum timeout */
 123         sh_tmu_write(p, TCOR, 0xffffffff);
 124         sh_tmu_write(p, TCNT, 0xffffffff);
 125
 126         /* configure channel to parent clock / 4, irq off */
 127         p->rate = clk_get_rate(p->clk) / 4;
 128         sh_tmu_write(p, TCR, 0x0000);
 129
 130         /* enable channel */
 131         sh_tmu_start_stop_ch(p, 1);
 132
 133         return 0;
 134 }
 135
 136 static void sh_tmu_disable(struct sh_tmu_priv *p)
 137 {
 138         /* disable channel */
 139         sh_tmu_start_stop_ch(p, 0);
 140
 141         /* stop clock */
 142         clk_disable(p->clk);
 143 }
 144
 145 static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
 146                             int periodic)
 147 {
 148         /* stop timer */
 149         sh_tmu_start_stop_ch(p, 0);
 150
 151         /* acknowledge interrupt */
 152         sh_tmu_read(p, TCR);
 153
 154         /* enable interrupt */
 155         sh_tmu_write(p, TCR, 0x0020);
 156
 157         /* reload delta value in case of periodic timer */
 158         if (periodic)
 159                 sh_tmu_write(p, TCOR, delta);
 160         else
 161                 sh_tmu_write(p, TCOR, 0);
 162
 163         sh_tmu_write(p, TCNT, delta);
 164
 165         /* start timer */
 166         sh_tmu_start_stop_ch(p, 1);
 167 }
 168
 169 static irqreturn_t sh_tmu_interrupt(int irq, void *dev_id)
 170 {
 171         struct sh_tmu_priv *p = dev_id;
 172
 173         /* disable or acknowledge interrupt */
 174         if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT)
 175                 sh_tmu_write(p, TCR, 0x0000);
 176         else
 177                 sh_tmu_write(p, TCR, 0x0020);
 178
 179         /* notify clockevent layer */
 180         p->ced.event_handler(&p->ced);
 181         return IRQ_HANDLED;
 182 }
 183
 184 static struct sh_tmu_priv *cs_to_sh_tmu(struct clocksource *cs)
 185 {
 186         return container_of(cs, struct sh_tmu_priv, cs);
 187 }
 188
 189 static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
 190 {
 191         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 192
 193         return sh_tmu_read(p, TCNT) ^ 0xffffffff;
 194 }
 195
 196 static int sh_tmu_clocksource_enable(struct clocksource *cs)
 197 {
 198         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 199         int ret;
 200
 201         ret = sh_tmu_enable(p);
 202         if (ret)
 203                 return ret;
 204
 205         /* TODO: calculate good shift from rate and counter bit width */
 206         cs->shift = 10;
 207         cs->mult = clocksource_hz2mult(p->rate, cs->shift);
 208         return 0;
 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         pr_info("sh_tmu: %s used as clock source\n", cs->name);
 229         clocksource_register(cs);
 230         return 0;
 231 }
 232
 233 static struct sh_tmu_priv *ced_to_sh_tmu(struct clock_event_device *ced)
 234 {
 235         return container_of(ced, struct sh_tmu_priv, ced);
 236 }
 237
 238 static void sh_tmu_clock_event_start(struct sh_tmu_priv *p, int periodic)
 239 {
 240         struct clock_event_device *ced = &p->ced;
 241
 242         sh_tmu_enable(p);
 243
 244         /* TODO: calculate good shift from rate and counter bit width */
 245
 246         ced->shift = 32;
 247         ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
 248         ced->max_delta_ns = clockevent_delta2ns(0xffffffff, ced);
 249         ced->min_delta_ns = 5000;
 250
 251         if (periodic) {
 252                 p->periodic = (p->rate + HZ/2) / HZ;
 253                 sh_tmu_set_next(p, p->periodic, 1);
 254         }
 255 }
 256
 257 static void sh_tmu_clock_event_mode(enum clock_event_mode mode,
 258                                     struct clock_event_device *ced)
 259 {
 260         struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
 261         int disabled = 0;
 262
 263         /* deal with old setting first */
 264         switch (ced->mode) {
 265         case CLOCK_EVT_MODE_PERIODIC:
 266         case CLOCK_EVT_MODE_ONESHOT:
 267                 sh_tmu_disable(p);
 268                 disabled = 1;
 269                 break;
 270         default:
 271                 break;
 272         }
 273
 274         switch (mode) {
 275         case CLOCK_EVT_MODE_PERIODIC:
 276                 pr_info("sh_tmu: %s used for periodic clock events\n",
 277                         ced->name);
 278                 sh_tmu_clock_event_start(p, 1);
 279                 break;
 280         case CLOCK_EVT_MODE_ONESHOT:
 281                 pr_info("sh_tmu: %s used for oneshot clock events\n",
 282                         ced->name);
 283                 sh_tmu_clock_event_start(p, 0);
 284                 break;
 285         case CLOCK_EVT_MODE_UNUSED:
 286                 if (!disabled)
 287                         sh_tmu_disable(p);
 288                 break;
 289         case CLOCK_EVT_MODE_SHUTDOWN:
 290         default:
 291                 break;
 292         }
 293 }
 294
 295 static int sh_tmu_clock_event_next(unsigned long delta,
 296                                    struct clock_event_device *ced)
 297 {
 298         struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
 299
 300         BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
 301
 302         /* program new delta value */
 303         sh_tmu_set_next(p, delta, 0);
 304         return 0;
 305 }
 306
 307 static void sh_tmu_register_clockevent(struct sh_tmu_priv *p,
 308                                        char *name, unsigned long rating)
 309 {
 310         struct clock_event_device *ced = &p->ced;
 311         int ret;
 312
 313         memset(ced, 0, sizeof(*ced));
 314
 315         ced->name = name;
 316         ced->features = CLOCK_EVT_FEAT_PERIODIC;
 317         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
 318         ced->rating = rating;
 319         ced->cpumask = cpumask_of(0);
 320         ced->set_next_event = sh_tmu_clock_event_next;
 321         ced->set_mode = sh_tmu_clock_event_mode;
 322
 323         ret = setup_irq(p->irqaction.irq, &p->irqaction);
 324         if (ret) {
 325                 pr_err("sh_tmu: failed to request irq %d\n",
 326                        p->irqaction.irq);
 327                 return;
 328         }
 329
 330         pr_info("sh_tmu: %s used for clock events\n", ced->name);
 331         clockevents_register_device(ced);
 332 }
 333
 334 static int sh_tmu_register(struct sh_tmu_priv *p, char *name,
 335                     unsigned long clockevent_rating,
 336                     unsigned long clocksource_rating)
 337 {
 338         if (clockevent_rating)
 339                 sh_tmu_register_clockevent(p, name, clockevent_rating);
 340         else if (clocksource_rating)
 341                 sh_tmu_register_clocksource(p, name, clocksource_rating);
 342
 343         return 0;
 344 }
 345
 346 static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
 347 {
 348         struct sh_timer_config *cfg = pdev->dev.platform_data;
 349         struct resource *res;
 350         int irq, ret;
 351         ret = -ENXIO;
 352
 353         memset(p, 0, sizeof(*p));
 354         p->pdev = pdev;
 355
 356         if (!cfg) {
 357                 dev_err(&p->pdev->dev, "missing platform data\n");
 358                 goto err0;
 359         }
 360
 361         platform_set_drvdata(pdev, p);
 362
 363         res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
 364         if (!res) {
 365                 dev_err(&p->pdev->dev, "failed to get I/O memory\n");
 366                 goto err0;
 367         }
 368
 369         irq = platform_get_irq(p->pdev, 0);
 370         if (irq < 0) {
 371                 dev_err(&p->pdev->dev, "failed to get irq\n");
 372                 goto err0;
 373         }
 374
 375         /* map memory, let mapbase point to our channel */
 376         p->mapbase = ioremap_nocache(res->start, resource_size(res));
 377         if (p->mapbase == NULL) {
 378                 pr_err("sh_tmu: failed to remap I/O memory\n");
 379                 goto err0;
 380         }
 381
 382         /* setup data for setup_irq() (too early for request_irq()) */
 383         p->irqaction.name = cfg->name;
 384         p->irqaction.handler = sh_tmu_interrupt;
 385         p->irqaction.dev_id = p;
 386         p->irqaction.irq = irq;
 387         p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL;
 388         p->irqaction.mask = CPU_MASK_NONE;
 389
 390         /* get hold of clock */
 391         p->clk = clk_get(&p->pdev->dev, cfg->clk);
 392         if (IS_ERR(p->clk)) {
 393                 pr_err("sh_tmu: cannot get clock \"%s\"\n", cfg->clk);
 394                 ret = PTR_ERR(p->clk);
 395                 goto err1;
 396         }
 397
 398         return sh_tmu_register(p, cfg->name,
 399                                cfg->clockevent_rating,
 400                                cfg->clocksource_rating);
 401  err1:
 402         iounmap(p->mapbase);
 403  err0:
 404         return ret;
 405 }
 406
 407 static int __devinit sh_tmu_probe(struct platform_device *pdev)
 408 {
 409         struct sh_tmu_priv *p = platform_get_drvdata(pdev);
 410         struct sh_timer_config *cfg = pdev->dev.platform_data;
 411         int ret;
 412
 413         if (p) {
 414                 pr_info("sh_tmu: %s kept as earlytimer\n", cfg->name);
 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");