arch/blackfin/kernel/time-ts.c

   1 /*
   2  * Based on arm clockevents implementation and old bfin time tick.
   3  *
   4  * Copyright 2008-2009 Analog Devics Inc.
   5  *                2008 GeoTechnologies
   6  *                     Vitja Makarov
   7  *
   8  * Licensed under the GPL-2
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/profile.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/time.h>
  15 #include <linux/timex.h>
  16 #include <linux/irq.h>
  17 #include <linux/clocksource.h>
  18 #include <linux/clockchips.h>
  19 #include <linux/cpufreq.h>
  20
  21 #include <asm/blackfin.h>
  22 #include <asm/time.h>
  23 #include <asm/gptimers.h>
  24 #include <asm/nmi.h>
  25
  26
  27 #if defined(CONFIG_CYCLES_CLOCKSOURCE)
  28
  29 static notrace cycle_t bfin_read_cycles(struct clocksource *cs)
  30 {
  31 #ifdef CONFIG_CPU_FREQ
  32         return __bfin_cycles_off + (get_cycles() << __bfin_cycles_mod);
  33 #else
  34         return get_cycles();
  35 #endif
  36 }
  37
  38 static struct clocksource bfin_cs_cycles = {
  39         .name           = "bfin_cs_cycles",
  40         .rating         = 400,
  41         .read           = bfin_read_cycles,
  42         .mask           = CLOCKSOURCE_MASK(64),
  43         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  44 };
  45
  46 static inline unsigned long long bfin_cs_cycles_sched_clock(void)
  47 {
  48         return clocksource_cyc2ns(bfin_read_cycles(&bfin_cs_cycles),
  49                 bfin_cs_cycles.mult, bfin_cs_cycles.shift);
  50 }
  51
  52 static int __init bfin_cs_cycles_init(void)
  53 {
  54         if (clocksource_register_hz(&bfin_cs_cycles, get_cclk()))
  55                 panic("failed to register clocksource");
  56
  57         return 0;
  58 }
  59 #else
  60 # define bfin_cs_cycles_init()
  61 #endif
  62
  63 #ifdef CONFIG_GPTMR0_CLOCKSOURCE
  64
  65 void __init setup_gptimer0(void)
  66 {
  67         disable_gptimers(TIMER0bit);
  68
  69 #ifdef CONFIG_BF60x
  70         bfin_write16(TIMER_DATA_IMSK, 0);
  71         set_gptimer_config(TIMER0_id,  TIMER_OUT_DIS
  72                 | TIMER_MODE_PWM_CONT | TIMER_PULSE_HI | TIMER_IRQ_PER);
  73 #else
  74         set_gptimer_config(TIMER0_id, \
  75                 TIMER_OUT_DIS | TIMER_PERIOD_CNT | TIMER_MODE_PWM);
  76 #endif
  77         set_gptimer_period(TIMER0_id, -1);
  78         set_gptimer_pwidth(TIMER0_id, -2);
  79         SSYNC();
  80         enable_gptimers(TIMER0bit);
  81 }
  82
  83 static cycle_t bfin_read_gptimer0(struct clocksource *cs)
  84 {
  85         return bfin_read_TIMER0_COUNTER();
  86 }
  87
  88 static struct clocksource bfin_cs_gptimer0 = {
  89         .name           = "bfin_cs_gptimer0",
  90         .rating         = 350,
  91         .read           = bfin_read_gptimer0,
  92         .mask           = CLOCKSOURCE_MASK(32),
  93         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  94 };
  95
  96 static inline unsigned long long bfin_cs_gptimer0_sched_clock(void)
  97 {
  98         return clocksource_cyc2ns(bfin_read_TIMER0_COUNTER(),
  99                 bfin_cs_gptimer0.mult, bfin_cs_gptimer0.shift);
 100 }
 101
 102 static int __init bfin_cs_gptimer0_init(void)
 103 {
 104         setup_gptimer0();
 105
 106         if (clocksource_register_hz(&bfin_cs_gptimer0, get_sclk()))
 107                 panic("failed to register clocksource");
 108
 109         return 0;
 110 }
 111 #else
 112 # define bfin_cs_gptimer0_init()
 113 #endif
 114
 115 #if defined(CONFIG_GPTMR0_CLOCKSOURCE) || defined(CONFIG_CYCLES_CLOCKSOURCE)
 116 /* prefer to use cycles since it has higher rating */
 117 notrace unsigned long long sched_clock(void)
 118 {
 119 #if defined(CONFIG_CYCLES_CLOCKSOURCE)
 120         return bfin_cs_cycles_sched_clock();
 121 #else
 122         return bfin_cs_gptimer0_sched_clock();
 123 #endif
 124 }
 125 #endif
 126
 127 #if defined(CONFIG_TICKSOURCE_GPTMR0)
 128 static int bfin_gptmr0_set_next_event(unsigned long cycles,
 129                                      struct clock_event_device *evt)
 130 {
 131         disable_gptimers(TIMER0bit);
 132
 133         /* it starts counting three SCLK cycles after the TIMENx bit is set */
 134         set_gptimer_pwidth(TIMER0_id, cycles - 3);
 135         enable_gptimers(TIMER0bit);
 136         return 0;
 137 }
 138
 139 static int bfin_gptmr0_set_periodic(struct clock_event_device *evt)
 140 {
 141 #ifndef CONFIG_BF60x
 142         set_gptimer_config(TIMER0_id,
 143                            TIMER_OUT_DIS | TIMER_IRQ_ENA |
 144                            TIMER_PERIOD_CNT | TIMER_MODE_PWM);
 145 #else
 146         set_gptimer_config(TIMER0_id,
 147                            TIMER_OUT_DIS | TIMER_MODE_PWM_CONT |
 148                            TIMER_PULSE_HI | TIMER_IRQ_PER);
 149 #endif
 150
 151         set_gptimer_period(TIMER0_id, get_sclk() / HZ);
 152         set_gptimer_pwidth(TIMER0_id, get_sclk() / HZ - 1);
 153         enable_gptimers(TIMER0bit);
 154         return 0;
 155 }
 156
 157 static int bfin_gptmr0_set_oneshot(struct clock_event_device *evt)
 158 {
 159         disable_gptimers(TIMER0bit);
 160 #ifndef CONFIG_BF60x
 161         set_gptimer_config(TIMER0_id,
 162                            TIMER_OUT_DIS | TIMER_IRQ_ENA | TIMER_MODE_PWM);
 163 #else
 164         set_gptimer_config(TIMER0_id,
 165                            TIMER_OUT_DIS | TIMER_MODE_PWM | TIMER_PULSE_HI |
 166                            TIMER_IRQ_WID_DLY);
 167 #endif
 168
 169         set_gptimer_period(TIMER0_id, 0);
 170         return 0;
 171 }
 172
 173 static int bfin_gptmr0_shutdown(struct clock_event_device *evt)
 174 {
 175         disable_gptimers(TIMER0bit);
 176         return 0;
 177 }
 178
 179 static void bfin_gptmr0_ack(void)
 180 {
 181         clear_gptimer_intr(TIMER0_id);
 182 }
 183
 184 static void __init bfin_gptmr0_init(void)
 185 {
 186         disable_gptimers(TIMER0bit);
 187 }
 188
 189 #ifdef CONFIG_CORE_TIMER_IRQ_L1
 190 __attribute__((l1_text))
 191 #endif
 192 irqreturn_t bfin_gptmr0_interrupt(int irq, void *dev_id)
 193 {
 194         struct clock_event_device *evt = dev_id;
 195         smp_mb();
 196         /*
 197          * We want to ACK before we handle so that we can handle smaller timer
 198          * intervals.  This way if the timer expires again while we're handling
 199          * things, we're more likely to see that 2nd int rather than swallowing
 200          * it by ACKing the int at the end of this handler.
 201          */
 202         bfin_gptmr0_ack();
 203         evt->event_handler(evt);
 204         return IRQ_HANDLED;
 205 }
 206
 207 static struct irqaction gptmr0_irq = {
 208         .name           = "Blackfin GPTimer0",
 209         .flags          = IRQF_TIMER | IRQF_IRQPOLL | IRQF_PERCPU,
 210         .handler        = bfin_gptmr0_interrupt,
 211 };
 212
 213 static struct clock_event_device clockevent_gptmr0 = {
 214         .name                   = "bfin_gptimer0",
 215         .rating                 = 300,
 216         .irq                    = IRQ_TIMER0,
 217         .shift                  = 32,
 218         .features               = CLOCK_EVT_FEAT_PERIODIC |
 219                                   CLOCK_EVT_FEAT_ONESHOT,
 220         .set_next_event         = bfin_gptmr0_set_next_event,
 221         .set_state_shutdown     = bfin_gptmr0_shutdown,
 222         .set_state_periodic     = bfin_gptmr0_set_periodic,
 223         .set_state_oneshot      = bfin_gptmr0_set_oneshot,
 224 };
 225
 226 static void __init bfin_gptmr0_clockevent_init(struct clock_event_device *evt)
 227 {
 228         unsigned long clock_tick;
 229
 230         clock_tick = get_sclk();
 231         evt->mult = div_sc(clock_tick, NSEC_PER_SEC, evt->shift);
 232         evt->max_delta_ns = clockevent_delta2ns(-1, evt);
 233         evt->min_delta_ns = clockevent_delta2ns(100, evt);
 234
 235         evt->cpumask = cpumask_of(0);
 236
 237         clockevents_register_device(evt);
 238 }
 239 #endif /* CONFIG_TICKSOURCE_GPTMR0 */
 240
 241 #if defined(CONFIG_TICKSOURCE_CORETMR)
 242 /* per-cpu local core timer */
 243 DEFINE_PER_CPU(struct clock_event_device, coretmr_events);
 244
 245 static int bfin_coretmr_set_next_event(unsigned long cycles,
 246                                 struct clock_event_device *evt)
 247 {
 248         bfin_write_TCNTL(TMPWR);
 249         CSYNC();
 250         bfin_write_TCOUNT(cycles);
 251         CSYNC();
 252         bfin_write_TCNTL(TMPWR | TMREN);
 253         return 0;
 254 }
 255
 256 static int bfin_coretmr_set_periodic(struct clock_event_device *evt)
 257 {
 258         unsigned long tcount = ((get_cclk() / (HZ * TIME_SCALE)) - 1);
 259
 260         bfin_write_TCNTL(TMPWR);
 261         CSYNC();
 262         bfin_write_TSCALE(TIME_SCALE - 1);
 263         bfin_write_TPERIOD(tcount);
 264         bfin_write_TCOUNT(tcount);
 265         CSYNC();
 266         bfin_write_TCNTL(TMPWR | TMREN | TAUTORLD);
 267         return 0;
 268 }
 269
 270 static int bfin_coretmr_set_oneshot(struct clock_event_device *evt)
 271 {
 272         bfin_write_TCNTL(TMPWR);
 273         CSYNC();
 274         bfin_write_TSCALE(TIME_SCALE - 1);
 275         bfin_write_TPERIOD(0);
 276         bfin_write_TCOUNT(0);
 277         return 0;
 278 }
 279
 280 static int bfin_coretmr_shutdown(struct clock_event_device *evt)
 281 {
 282         bfin_write_TCNTL(0);
 283         CSYNC();
 284         return 0;
 285 }
 286
 287 void bfin_coretmr_init(void)
 288 {
 289         /* power up the timer, but don't enable it just yet */
 290         bfin_write_TCNTL(TMPWR);
 291         CSYNC();
 292
 293         /* the TSCALE prescaler counter. */
 294         bfin_write_TSCALE(TIME_SCALE - 1);
 295         bfin_write_TPERIOD(0);
 296         bfin_write_TCOUNT(0);
 297
 298         CSYNC();
 299 }
 300
 301 #ifdef CONFIG_CORE_TIMER_IRQ_L1
 302 __attribute__((l1_text))
 303 #endif
 304
 305 irqreturn_t bfin_coretmr_interrupt(int irq, void *dev_id)
 306 {
 307         int cpu = smp_processor_id();
 308         struct clock_event_device *evt = &per_cpu(coretmr_events, cpu);
 309
 310         smp_mb();
 311         evt->event_handler(evt);
 312
 313         touch_nmi_watchdog();
 314
 315         return IRQ_HANDLED;
 316 }
 317
 318 static struct irqaction coretmr_irq = {
 319         .name           = "Blackfin CoreTimer",
 320         .flags          = IRQF_TIMER | IRQF_IRQPOLL | IRQF_PERCPU,
 321         .handler        = bfin_coretmr_interrupt,
 322 };
 323
 324 void bfin_coretmr_clockevent_init(void)
 325 {
 326         unsigned long clock_tick;
 327         unsigned int cpu = smp_processor_id();
 328         struct clock_event_device *evt = &per_cpu(coretmr_events, cpu);
 329
 330 #ifdef CONFIG_SMP
 331         evt->broadcast = smp_timer_broadcast;
 332 #endif
 333
 334         evt->name = "bfin_core_timer";
 335         evt->rating = 350;
 336         evt->irq = -1;
 337         evt->shift = 32;
 338         evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 339         evt->set_next_event = bfin_coretmr_set_next_event;
 340         evt->set_state_shutdown = bfin_coretmr_shutdown;
 341         evt->set_state_periodic = bfin_coretmr_set_periodic;
 342         evt->set_state_oneshot = bfin_coretmr_set_oneshot;
 343
 344         clock_tick = get_cclk() / TIME_SCALE;
 345         evt->mult = div_sc(clock_tick, NSEC_PER_SEC, evt->shift);
 346         evt->max_delta_ns = clockevent_delta2ns(-1, evt);
 347         evt->min_delta_ns = clockevent_delta2ns(100, evt);
 348
 349         evt->cpumask = cpumask_of(cpu);
 350
 351         clockevents_register_device(evt);
 352 }
 353 #endif /* CONFIG_TICKSOURCE_CORETMR */
 354
 355
 356 void read_persistent_clock(struct timespec *ts)
 357 {
 358         time_t secs_since_1970 = (365 * 37 + 9) * 24 * 60 * 60; /* 1 Jan 2007 */
 359         ts->tv_sec = secs_since_1970;
 360         ts->tv_nsec = 0;
 361 }
 362
 363 void __init time_init(void)
 364 {
 365
 366 #ifdef CONFIG_RTC_DRV_BFIN
 367         /* [#2663] hack to filter junk RTC values that would cause
 368          * userspace to have to deal with time values greater than
 369          * 2^31 seconds (which uClibc cannot cope with yet)
 370          */
 371         if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) {
 372                 printk(KERN_NOTICE "bfin-rtc: invalid date; resetting\n");
 373                 bfin_write_RTC_STAT(0);
 374         }
 375 #endif
 376
 377         bfin_cs_cycles_init();
 378         bfin_cs_gptimer0_init();
 379
 380 #if defined(CONFIG_TICKSOURCE_CORETMR)
 381         bfin_coretmr_init();
 382         setup_irq(IRQ_CORETMR, &coretmr_irq);
 383         bfin_coretmr_clockevent_init();
 384 #endif
 385
 386 #if defined(CONFIG_TICKSOURCE_GPTMR0)
 387         bfin_gptmr0_init();
 388         setup_irq(IRQ_TIMER0, &gptmr0_irq);
 389         gptmr0_irq.dev_id = &clockevent_gptmr0;
 390         bfin_gptmr0_clockevent_init(&clockevent_gptmr0);
 391 #endif
 392
 393 #if !defined(CONFIG_TICKSOURCE_CORETMR) && !defined(CONFIG_TICKSOURCE_GPTMR0)
 394 # error at least one clock event device is required
 395 #endif
 396 }