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         int i;
 201
 202         /* Global init of each 64-bit timer as a whole */
 203         for(i=0; i<2; i++) {
 204                 u32 tgcr;
 205                 void __iomem *base = dtip[i].base;
 206
 207                 /* Disabled, Internal clock source */
 208                 __raw_writel(0, base + TCR);
 209
 210                 /* reset both timers, no pre-scaler for timer34 */
 211                 tgcr = 0;
 212                 __raw_writel(tgcr, base + TGCR);
 213
 214                 /* Set both timers to unchained 32-bit */
 215                 tgcr = TGCR_TIMMODE_32BIT_UNCHAINED << TGCR_TIMMODE_SHIFT;
 216                 __raw_writel(tgcr, base + TGCR);
 217
 218                 /* Unreset timers */
 219                 tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
 220                         (TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
 221                 __raw_writel(tgcr, base + TGCR);
 222
 223                 /* Init both counters to zero */
 224                 __raw_writel(0, base + TIM12);
 225                 __raw_writel(0, base + TIM34);
 226         }
 227
 228         /* Init of each timer as a 32-bit timer */
 229         for (i=0; i< ARRAY_SIZE(timers); i++) {
 230                 struct timer_s *t = &timers[i];
 231                 int timer = ID_TO_TIMER(t->id);
 232                 u32 irq;
 233
 234                 t->base = dtip[timer].base;
 235
 236                 if (IS_TIMER_BOT(t->id)) {
 237                         t->enamode_shift = 6;
 238                         t->tim_off = TIM12;
 239                         t->prd_off = PRD12;
 240                         irq = dtip[timer].bottom_irq;
 241                 } else {
 242                         t->enamode_shift = 22;
 243                         t->tim_off = TIM34;
 244                         t->prd_off = PRD34;
 245                         irq = dtip[timer].top_irq;
 246                 }
 247
 248                 /* Register interrupt */
 249                 t->irqaction.name = t->name;
 250                 t->irqaction.dev_id = (void *)t;
 251
 252                 if (t->irqaction.handler != NULL) {
 253                         irq = USING_COMPARE(t) ? dtip[i].cmp_irq : irq;
 254                         setup_irq(irq, &t->irqaction);
 255                 }
 256
 257                 timer32_config(&timers[i]);
 258         }
 259 }
 260
 261 /*
 262  * clocksource
 263  */
 264 static cycle_t read_cycles(struct clocksource *cs)
 265 {
 266         struct timer_s *t = &timers[TID_CLOCKSOURCE];
 267
 268         return (cycles_t)timer32_read(t);
 269 }
 270
 271 static struct clocksource clocksource_davinci = {
 272         .rating         = 300,
 273         .read           = read_cycles,
 274         .mask           = CLOCKSOURCE_MASK(32),
 275         .shift          = 24,
 276         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 277 };
 278
 279 /*
 280  * clockevent
 281  */
 282 static int davinci_set_next_event(unsigned long cycles,
 283                                   struct clock_event_device *evt)
 284 {
 285         struct timer_s *t = &timers[TID_CLOCKEVENT];
 286
 287         t->period = cycles;
 288         timer32_config(t);
 289         return 0;
 290 }
 291
 292 static void davinci_set_mode(enum clock_event_mode mode,
 293                              struct clock_event_device *evt)
 294 {
 295         struct timer_s *t = &timers[TID_CLOCKEVENT];
 296
 297         switch (mode) {
 298         case CLOCK_EVT_MODE_PERIODIC:
 299                 t->period = davinci_clock_tick_rate / (HZ);
 300                 t->opts &= ~TIMER_OPTS_STATE_MASK;
 301                 t->opts |= TIMER_OPTS_PERIODIC;
 302                 timer32_config(t);
 303                 break;
 304         case CLOCK_EVT_MODE_ONESHOT:
 305                 t->opts &= ~TIMER_OPTS_STATE_MASK;
 306                 t->opts |= TIMER_OPTS_ONESHOT;
 307                 break;
 308         case CLOCK_EVT_MODE_UNUSED:
 309         case CLOCK_EVT_MODE_SHUTDOWN:
 310                 t->opts &= ~TIMER_OPTS_STATE_MASK;
 311                 t->opts |= TIMER_OPTS_DISABLED;
 312                 break;
 313         case CLOCK_EVT_MODE_RESUME:
 314                 break;
 315         }
 316 }
 317
 318 static struct clock_event_device clockevent_davinci = {
 319         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 320         .shift          = 32,
 321         .set_next_event = davinci_set_next_event,
 322         .set_mode       = davinci_set_mode,
 323 };
 324
 325
 326 static void __init davinci_timer_init(void)
 327 {
 328         struct clk *timer_clk;
 329         struct davinci_soc_info *soc_info = &davinci_soc_info;
 330         unsigned int clockevent_id;
 331         unsigned int clocksource_id;
 332         static char err[] __initdata = KERN_ERR
 333                 "%s: can't register clocksource!\n";
 334
 335         clockevent_id = soc_info->timer_info->clockevent_id;
 336         clocksource_id = soc_info->timer_info->clocksource_id;
 337
 338         timers[TID_CLOCKEVENT].id = clockevent_id;
 339         timers[TID_CLOCKSOURCE].id = clocksource_id;
 340
 341         /*
 342          * If using same timer for both clock events & clocksource,
 343          * a compare register must be used to generate an event interrupt.
 344          * This is equivalent to a oneshot timer only (not periodic).
 345          */
 346         if (clockevent_id == clocksource_id) {
 347                 struct davinci_timer_instance *dtip =
 348                                 soc_info->timer_info->timers;
 349                 int event_timer = ID_TO_TIMER(clockevent_id);
 350
 351                 /* Only bottom timers can use compare regs */
 352                 if (IS_TIMER_TOP(clockevent_id))
 353                         pr_warning("davinci_timer_init: Invalid use"
 354                                 " of system timers.  Results unpredictable.\n");
 355                 else if ((dtip[event_timer].cmp_off == 0)
 356                                 || (dtip[event_timer].cmp_irq == 0))
 357                         pr_warning("davinci_timer_init:  Invalid timer instance"
 358                                 " setup.  Results unpredictable.\n");
 359                 else {
 360                         timers[TID_CLOCKEVENT].opts |= TIMER_OPTS_USE_COMPARE;
 361                         clockevent_davinci.features = CLOCK_EVT_FEAT_ONESHOT;
 362                 }
 363         }
 364
 365         /* init timer hw */
 366         timer_init();
 367
 368         timer_clk = clk_get(NULL, "timer0");
 369         BUG_ON(IS_ERR(timer_clk));
 370         clk_enable(timer_clk);
 371
 372         davinci_clock_tick_rate = clk_get_rate(timer_clk);
 373
 374         /* setup clocksource */
 375         clocksource_davinci.name = id_to_name[clocksource_id];
 376         clocksource_davinci.mult =
 377                 clocksource_khz2mult(davinci_clock_tick_rate/1000,
 378                                      clocksource_davinci.shift);
 379         if (clocksource_register(&clocksource_davinci))
 380                 printk(err, clocksource_davinci.name);
 381
 382         /* setup clockevent */
 383         clockevent_davinci.name = id_to_name[timers[TID_CLOCKEVENT].id];
 384         clockevent_davinci.mult = div_sc(davinci_clock_tick_rate, NSEC_PER_SEC,
 385                                          clockevent_davinci.shift);
 386         clockevent_davinci.max_delta_ns =
 387                 clockevent_delta2ns(0xfffffffe, &clockevent_davinci);
 388         clockevent_davinci.min_delta_ns = 50000; /* 50 usec */
 389
 390         clockevent_davinci.cpumask = cpumask_of(0);
 391         clockevents_register_device(&clockevent_davinci);
 392 }
 393
 394 struct sys_timer davinci_timer = {
 395         .init   = davinci_timer_init,
 396 };
 397
 398
 399 /* reset board using watchdog timer */
 400 void davinci_watchdog_reset(void)
 401 {
 402         u32 tgcr, wdtcr;
 403         struct platform_device *pdev = &davinci_wdt_device;
 404         void __iomem *base = IO_ADDRESS(pdev->resource[0].start);
 405         struct clk *wd_clk;
 406
 407         wd_clk = clk_get(&pdev->dev, NULL);
 408         if (WARN_ON(IS_ERR(wd_clk)))
 409                 return;
 410         clk_enable(wd_clk);
 411
 412         /* disable, internal clock source */
 413         __raw_writel(0, base + TCR);
 414
 415         /* reset timer, set mode to 64-bit watchdog, and unreset */
 416         tgcr = 0;
 417         __raw_writel(tgcr, base + TGCR);
 418         tgcr = TGCR_TIMMODE_64BIT_WDOG << TGCR_TIMMODE_SHIFT;
 419         tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
 420                 (TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
 421         __raw_writel(tgcr, base + TGCR);
 422
 423         /* clear counter and period regs */
 424         __raw_writel(0, base + TIM12);
 425         __raw_writel(0, base + TIM34);
 426         __raw_writel(0, base + PRD12);
 427         __raw_writel(0, base + PRD34);
 428
 429         /* put watchdog in pre-active state */
 430         wdtcr = __raw_readl(base + WDTCR);
 431         wdtcr = (WDTCR_WDKEY_SEQ0 << WDTCR_WDKEY_SHIFT) |
 432                 (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
 433         __raw_writel(wdtcr, base + WDTCR);
 434
 435         /* put watchdog in active state */
 436         wdtcr = (WDTCR_WDKEY_SEQ1 << WDTCR_WDKEY_SHIFT) |
 437                 (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
 438         __raw_writel(wdtcr, base + WDTCR);
 439
 440         /* write an invalid value to the WDKEY field to trigger
 441          * a watchdog reset */
 442         wdtcr = 0x00004000;
 443         __raw_writel(wdtcr, base + WDTCR);
 444 }