arch/arm/mach-davinci/time.c

   1 /*
   2  * DaVinci timer subsystem
   3  *
   4  * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
   5  *
   6  * 2007 (c) MontaVista Software, Inc. This file is licensed under
   7  * the terms of the GNU General Public License version 2. This program
   8  * is licensed "as is" without any warranty of any kind, whether express
   9  * or implied.
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/types.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/clocksource.h>
  16 #include <linux/clockchips.h>
  17 #include <linux/io.h>
  18 #include <linux/clk.h>
  19 #include <linux/err.h>
  20 #include <linux/platform_device.h>
  21
  22 #include <mach/hardware.h>
  23 #include <asm/mach/irq.h>
  24 #include <asm/mach/time.h>
  25 #include <mach/cputype.h>
  26 #include <mach/time.h>
  27 #include "clock.h"
  28
  29 static struct clock_event_device clockevent_davinci;
  30 static unsigned int davinci_clock_tick_rate;
  31
  32 /*
  33  * This driver configures the 2 64-bit count-up timers as 4 independent
  34  * 32-bit count-up timers used as follows:
  35  */
  36
  37 enum {
  38         TID_CLOCKEVENT,
  39         TID_CLOCKSOURCE,
  40 };
  41
  42 /* Timer register offsets */
  43 #define PID12                   0x0
  44 #define TIM12                   0x10
  45 #define TIM34                   0x14
  46 #define PRD12                   0x18
  47 #define PRD34                   0x1c
  48 #define TCR                     0x20
  49 #define TGCR                    0x24
  50 #define WDTCR                   0x28
  51
  52 /* Offsets of the 8 compare registers */
  53 #define CMP12_0                 0x60
  54 #define CMP12_1                 0x64
  55 #define CMP12_2                 0x68
  56 #define CMP12_3                 0x6c
  57 #define CMP12_4                 0x70
  58 #define CMP12_5                 0x74
  59 #define CMP12_6                 0x78
  60 #define CMP12_7                 0x7c
  61
  62 /* Timer register bitfields */
  63 #define TCR_ENAMODE_DISABLE          0x0
  64 #define TCR_ENAMODE_ONESHOT          0x1
  65 #define TCR_ENAMODE_PERIODIC         0x2
  66 #define TCR_ENAMODE_MASK             0x3
  67
  68 #define TGCR_TIMMODE_SHIFT           2
  69 #define TGCR_TIMMODE_64BIT_GP        0x0
  70 #define TGCR_TIMMODE_32BIT_UNCHAINED 0x1
  71 #define TGCR_TIMMODE_64BIT_WDOG      0x2
  72 #define TGCR_TIMMODE_32BIT_CHAINED   0x3
  73
  74 #define TGCR_TIM12RS_SHIFT           0
  75 #define TGCR_TIM34RS_SHIFT           1
  76 #define TGCR_RESET                   0x0
  77 #define TGCR_UNRESET                 0x1
  78 #define TGCR_RESET_MASK              0x3
  79
  80 #define WDTCR_WDEN_SHIFT             14
  81 #define WDTCR_WDEN_DISABLE           0x0
  82 #define WDTCR_WDEN_ENABLE            0x1
  83 #define WDTCR_WDKEY_SHIFT            16
  84 #define WDTCR_WDKEY_SEQ0             0xa5c6
  85 #define WDTCR_WDKEY_SEQ1             0xda7e
  86
  87 struct timer_s {
  88         char *name;
  89         unsigned int id;
  90         unsigned long period;
  91         unsigned long opts;
  92         unsigned long flags;
  93         void __iomem *base;
  94         unsigned long tim_off;
  95         unsigned long prd_off;
  96         unsigned long enamode_shift;
  97         struct irqaction irqaction;
  98 };
  99 static struct timer_s timers[];
 100
 101 /* values for 'opts' field of struct timer_s */
 102 #define TIMER_OPTS_DISABLED             0x01
 103 #define TIMER_OPTS_ONESHOT              0x02
 104 #define TIMER_OPTS_PERIODIC             0x04
 105 #define TIMER_OPTS_STATE_MASK           0x07
 106
 107 #define TIMER_OPTS_USE_COMPARE          0x80000000
 108 #define USING_COMPARE(t)                ((t)->opts & TIMER_OPTS_USE_COMPARE)
 109
 110 static char *id_to_name[] = {
 111         [T0_BOT]        = "timer0_0",
 112         [T0_TOP]        = "timer0_1",
 113         [T1_BOT]        = "timer1_0",
 114         [T1_TOP]        = "timer1_1",
 115 };
 116
 117 static int timer32_config(struct timer_s *t)
 118 {
 119         u32 tcr;
 120         struct davinci_soc_info *soc_info = &davinci_soc_info;
 121
 122         if (USING_COMPARE(t)) {
 123                 struct davinci_timer_instance *dtip =
 124                                 soc_info->timer_info->timers;
 125                 int event_timer = ID_TO_TIMER(timers[TID_CLOCKEVENT].id);
 126
 127                 /*
 128                  * Next interrupt should be the current time reg value plus
 129                  * the new period (using 32-bit unsigned addition/wrapping
 130                  * to 0 on overflow).  This assumes that the clocksource
 131                  * is setup to count to 2^32-1 before wrapping around to 0.
 132                  */
 133                 __raw_writel(__raw_readl(t->base + t->tim_off) + t->period,
 134                         t->base + dtip[event_timer].cmp_off);
 135         } else {
 136                 tcr = __raw_readl(t->base + TCR);
 137
 138                 /* disable timer */
 139                 tcr &= ~(TCR_ENAMODE_MASK << t->enamode_shift);
 140                 __raw_writel(tcr, t->base + TCR);
 141
 142                 /* reset counter to zero, set new period */
 143                 __raw_writel(0, t->base + t->tim_off);
 144                 __raw_writel(t->period, t->base + t->prd_off);
 145
 146                 /* Set enable mode */
 147                 if (t->opts & TIMER_OPTS_ONESHOT)
 148                         tcr |= TCR_ENAMODE_ONESHOT << t->enamode_shift;
 149                 else if (t->opts & TIMER_OPTS_PERIODIC)
 150                         tcr |= TCR_ENAMODE_PERIODIC << t->enamode_shift;
 151
 152                 __raw_writel(tcr, t->base + TCR);
 153         }
 154         return 0;
 155 }
 156
 157 static inline u32 timer32_read(struct timer_s *t)
 158 {
 159         return __raw_readl(t->base + t->tim_off);
 160 }
 161
 162 static irqreturn_t timer_interrupt(int irq, void *dev_id)
 163 {
 164         struct clock_event_device *evt = &clockevent_davinci;
 165
 166         evt->event_handler(evt);
 167         return IRQ_HANDLED;
 168 }
 169
 170 /* called when 32-bit counter wraps */
 171 static irqreturn_t freerun_interrupt(int irq, void *dev_id)
 172 {
 173         return IRQ_HANDLED;
 174 }
 175
 176 static struct timer_s timers[] = {
 177         [TID_CLOCKEVENT] = {
 178                 .name      = "clockevent",
 179                 .opts      = TIMER_OPTS_DISABLED,
 180                 .irqaction = {
 181                         .flags   = IRQF_DISABLED | IRQF_TIMER,
 182                         .handler = timer_interrupt,
 183                 }
 184         },
 185         [TID_CLOCKSOURCE] = {
 186                 .name       = "free-run counter",
 187                 .period     = ~0,
 188                 .opts       = TIMER_OPTS_PERIODIC,
 189                 .irqaction = {
 190                         .flags   = IRQF_DISABLED | IRQF_TIMER,
 191                         .handler = freerun_interrupt,
 192                 }
 193         },
 194 };
 195
 196 static void __init timer_init(void)
 197 {
 198         struct davinci_soc_info *soc_info = &davinci_soc_info;
 199         struct davinci_timer_instance *dtip = soc_info->timer_info->timers;
 200         void __iomem *base[2];
 201         int i;
 202
 203         /* Global init of each 64-bit timer as a whole */
 204         for(i=0; i<2; i++) {
 205                 u32 tgcr;
 206
 207                 base[i] = ioremap(dtip[i].base, SZ_4K);
 208                 if (WARN_ON(!base[i]))
 209                         continue;
 210
 211                 /* Disabled, Internal clock source */
 212                 __raw_writel(0, base[i] + TCR);
 213
 214                 /* reset both timers, no pre-scaler for timer34 */
 215                 tgcr = 0;
 216                 __raw_writel(tgcr, base[i] + TGCR);
 217
 218                 /* Set both timers to unchained 32-bit */
 219                 tgcr = TGCR_TIMMODE_32BIT_UNCHAINED << TGCR_TIMMODE_SHIFT;
 220                 __raw_writel(tgcr, base[i] + TGCR);
 221
 222                 /* Unreset timers */
 223                 tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
 224                         (TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
 225                 __raw_writel(tgcr, base[i] + TGCR);
 226
 227                 /* Init both counters to zero */
 228                 __raw_writel(0, base[i] + TIM12);
 229                 __raw_writel(0, base[i] + TIM34);
 230         }
 231
 232         /* Init of each timer as a 32-bit timer */
 233         for (i=0; i< ARRAY_SIZE(timers); i++) {
 234                 struct timer_s *t = &timers[i];
 235                 int timer = ID_TO_TIMER(t->id);
 236                 u32 irq;
 237
 238                 t->base = base[timer];
 239                 if (!t->base)
 240                         continue;
 241
 242                 if (IS_TIMER_BOT(t->id)) {
 243                         t->enamode_shift = 6;
 244                         t->tim_off = TIM12;
 245                         t->prd_off = PRD12;
 246                         irq = dtip[timer].bottom_irq;
 247                 } else {
 248                         t->enamode_shift = 22;
 249                         t->tim_off = TIM34;
 250                         t->prd_off = PRD34;
 251                         irq = dtip[timer].top_irq;
 252                 }
 253
 254                 /* Register interrupt */
 255                 t->irqaction.name = t->name;
 256                 t->irqaction.dev_id = (void *)t;
 257
 258                 if (t->irqaction.handler != NULL) {
 259                         irq = USING_COMPARE(t) ? dtip[i].cmp_irq : irq;
 260                         setup_irq(irq, &t->irqaction);
 261                 }
 262         }
 263 }
 264
 265 /*
 266  * clocksource
 267  */
 268 static cycle_t read_cycles(struct clocksource *cs)
 269 {
 270         struct timer_s *t = &timers[TID_CLOCKSOURCE];
 271
 272         return (cycles_t)timer32_read(t);
 273 }
 274
 275 /*
 276  * Kernel assumes that sched_clock can be called early but may not have
 277  * things ready yet.
 278  */
 279 static cycle_t read_dummy(struct clocksource *cs)
 280 {
 281         return 0;
 282 }
 283
 284
 285 static struct clocksource clocksource_davinci = {
 286         .rating         = 300,
 287         .read           = read_dummy,
 288         .mask           = CLOCKSOURCE_MASK(32),
 289         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 290 };
 291
 292 /*
 293  * Overwrite weak default sched_clock with something more precise
 294  */
 295 unsigned long long notrace sched_clock(void)
 296 {
 297         const cycle_t cyc = clocksource_davinci.read(&clocksource_davinci);
 298
 299         return clocksource_cyc2ns(cyc, clocksource_davinci.mult,
 300                                 clocksource_davinci.shift);
 301 }
 302
 303 /*
 304  * clockevent
 305  */
 306 static int davinci_set_next_event(unsigned long cycles,
 307                                   struct clock_event_device *evt)
 308 {
 309         struct timer_s *t = &timers[TID_CLOCKEVENT];
 310
 311         t->period = cycles;
 312         timer32_config(t);
 313         return 0;
 314 }
 315
 316 static void davinci_set_mode(enum clock_event_mode mode,
 317                              struct clock_event_device *evt)
 318 {
 319         struct timer_s *t = &timers[TID_CLOCKEVENT];
 320
 321         switch (mode) {
 322         case CLOCK_EVT_MODE_PERIODIC:
 323                 t->period = davinci_clock_tick_rate / (HZ);
 324                 t->opts &= ~TIMER_OPTS_STATE_MASK;
 325                 t->opts |= TIMER_OPTS_PERIODIC;
 326                 timer32_config(t);
 327                 break;
 328         case CLOCK_EVT_MODE_ONESHOT:
 329                 t->opts &= ~TIMER_OPTS_STATE_MASK;
 330                 t->opts |= TIMER_OPTS_ONESHOT;
 331                 break;
 332         case CLOCK_EVT_MODE_UNUSED:
 333         case CLOCK_EVT_MODE_SHUTDOWN:
 334                 t->opts &= ~TIMER_OPTS_STATE_MASK;
 335                 t->opts |= TIMER_OPTS_DISABLED;
 336                 break;
 337         case CLOCK_EVT_MODE_RESUME:
 338                 break;
 339         }
 340 }
 341
 342 static struct clock_event_device clockevent_davinci = {
 343         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 344         .shift          = 32,
 345         .set_next_event = davinci_set_next_event,
 346         .set_mode       = davinci_set_mode,
 347 };
 348
 349
 350 static void __init davinci_timer_init(void)
 351 {
 352         struct clk *timer_clk;
 353         struct davinci_soc_info *soc_info = &davinci_soc_info;
 354         unsigned int clockevent_id;
 355         unsigned int clocksource_id;
 356         static char err[] __initdata = KERN_ERR
 357                 "%s: can't register clocksource!\n";
 358         int i;
 359
 360         clockevent_id = soc_info->timer_info->clockevent_id;
 361         clocksource_id = soc_info->timer_info->clocksource_id;
 362
 363         timers[TID_CLOCKEVENT].id = clockevent_id;
 364         timers[TID_CLOCKSOURCE].id = clocksource_id;
 365
 366         /*
 367          * If using same timer for both clock events & clocksource,
 368          * a compare register must be used to generate an event interrupt.
 369          * This is equivalent to a oneshot timer only (not periodic).
 370          */
 371         if (clockevent_id == clocksource_id) {
 372                 struct davinci_timer_instance *dtip =
 373                                 soc_info->timer_info->timers;
 374                 int event_timer = ID_TO_TIMER(clockevent_id);
 375
 376                 /* Only bottom timers can use compare regs */
 377                 if (IS_TIMER_TOP(clockevent_id))
 378                         pr_warning("davinci_timer_init: Invalid use"
 379                                 " of system timers.  Results unpredictable.\n");
 380                 else if ((dtip[event_timer].cmp_off == 0)
 381                                 || (dtip[event_timer].cmp_irq == 0))
 382                         pr_warning("davinci_timer_init:  Invalid timer instance"
 383                                 " setup.  Results unpredictable.\n");
 384                 else {
 385                         timers[TID_CLOCKEVENT].opts |= TIMER_OPTS_USE_COMPARE;
 386                         clockevent_davinci.features = CLOCK_EVT_FEAT_ONESHOT;
 387                 }
 388         }
 389
 390         timer_clk = clk_get(NULL, "timer0");
 391         BUG_ON(IS_ERR(timer_clk));
 392         clk_enable(timer_clk);
 393
 394         /* init timer hw */
 395         timer_init();
 396
 397         davinci_clock_tick_rate = clk_get_rate(timer_clk);
 398
 399         /* setup clocksource */
 400         clocksource_davinci.read = read_cycles;
 401         clocksource_davinci.name = id_to_name[clocksource_id];
 402         if (clocksource_register_hz(&clocksource_davinci,
 403                                     davinci_clock_tick_rate))
 404                 printk(err, clocksource_davinci.name);
 405
 406         /* setup clockevent */
 407         clockevent_davinci.name = id_to_name[timers[TID_CLOCKEVENT].id];
 408         clockevent_davinci.mult = div_sc(davinci_clock_tick_rate, NSEC_PER_SEC,
 409                                          clockevent_davinci.shift);
 410         clockevent_davinci.max_delta_ns =
 411                 clockevent_delta2ns(0xfffffffe, &clockevent_davinci);
 412         clockevent_davinci.min_delta_ns = 50000; /* 50 usec */
 413
 414         clockevent_davinci.cpumask = cpumask_of(0);
 415         clockevents_register_device(&clockevent_davinci);
 416
 417         for (i=0; i< ARRAY_SIZE(timers); i++)
 418                 timer32_config(&timers[i]);
 419 }
 420
 421 struct sys_timer davinci_timer = {
 422         .init   = davinci_timer_init,
 423 };
 424
 425
 426 /* reset board using watchdog timer */
 427 void davinci_watchdog_reset(struct platform_device *pdev)
 428 {
 429         u32 tgcr, wdtcr;
 430         void __iomem *base;
 431         struct clk *wd_clk;
 432
 433         base = ioremap(pdev->resource[0].start, SZ_4K);
 434         if (WARN_ON(!base))
 435                 return;
 436
 437         wd_clk = clk_get(&pdev->dev, NULL);
 438         if (WARN_ON(IS_ERR(wd_clk)))
 439                 return;
 440         clk_enable(wd_clk);
 441
 442         /* disable, internal clock source */
 443         __raw_writel(0, base + TCR);
 444
 445         /* reset timer, set mode to 64-bit watchdog, and unreset */
 446         tgcr = 0;
 447         __raw_writel(tgcr, base + TGCR);
 448         tgcr = TGCR_TIMMODE_64BIT_WDOG << TGCR_TIMMODE_SHIFT;
 449         tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
 450                 (TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
 451         __raw_writel(tgcr, base + TGCR);
 452
 453         /* clear counter and period regs */
 454         __raw_writel(0, base + TIM12);
 455         __raw_writel(0, base + TIM34);
 456         __raw_writel(0, base + PRD12);
 457         __raw_writel(0, base + PRD34);
 458
 459         /* put watchdog in pre-active state */
 460         wdtcr = __raw_readl(base + WDTCR);
 461         wdtcr = (WDTCR_WDKEY_SEQ0 << WDTCR_WDKEY_SHIFT) |
 462                 (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
 463         __raw_writel(wdtcr, base + WDTCR);
 464
 465         /* put watchdog in active state */
 466         wdtcr = (WDTCR_WDKEY_SEQ1 << WDTCR_WDKEY_SHIFT) |
 467                 (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
 468         __raw_writel(wdtcr, base + WDTCR);
 469
 470         /* write an invalid value to the WDKEY field to trigger
 471          * a watchdog reset */
 472         wdtcr = 0x00004000;
 473         __raw_writel(wdtcr, base + WDTCR);
 474 }