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 void bfin_gptmr0_set_mode(enum clock_event_mode mode,
 140                                 struct clock_event_device *evt)
 141 {
 142         switch (mode) {
 143         case CLOCK_EVT_MODE_PERIODIC: {
 144 #ifndef CONFIG_BF60x
 145                 set_gptimer_config(TIMER0_id, \
 146                         TIMER_OUT_DIS | TIMER_IRQ_ENA | \
 147                         TIMER_PERIOD_CNT | TIMER_MODE_PWM);
 148 #else
 149                 set_gptimer_config(TIMER0_id,  TIMER_OUT_DIS
 150                         | TIMER_MODE_PWM_CONT | TIMER_PULSE_HI | TIMER_IRQ_PER);
 151 #endif
 152
 153                 set_gptimer_period(TIMER0_id, get_sclk() / HZ);
 154                 set_gptimer_pwidth(TIMER0_id, get_sclk() / HZ - 1);
 155                 enable_gptimers(TIMER0bit);
 156                 break;
 157         }
 158         case CLOCK_EVT_MODE_ONESHOT:
 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, TIMER_OUT_DIS | TIMER_MODE_PWM
 165                         | TIMER_PULSE_HI | TIMER_IRQ_WID_DLY);
 166 #endif
 167
 168                 set_gptimer_period(TIMER0_id, 0);
 169                 break;
 170         case CLOCK_EVT_MODE_UNUSED:
 171         case CLOCK_EVT_MODE_SHUTDOWN:
 172                 disable_gptimers(TIMER0bit);
 173                 break;
 174         case CLOCK_EVT_MODE_RESUME:
 175                 break;
 176         }
 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 | CLOCK_EVT_FEAT_ONESHOT,
 219         .set_next_event = bfin_gptmr0_set_next_event,
 220         .set_mode       = bfin_gptmr0_set_mode,
 221 };
 222
 223 static void __init bfin_gptmr0_clockevent_init(struct clock_event_device *evt)
 224 {
 225         unsigned long clock_tick;
 226
 227         clock_tick = get_sclk();
 228         evt->mult = div_sc(clock_tick, NSEC_PER_SEC, evt->shift);
 229         evt->max_delta_ns = clockevent_delta2ns(-1, evt);
 230         evt->min_delta_ns = clockevent_delta2ns(100, evt);
 231
 232         evt->cpumask = cpumask_of(0);
 233
 234         clockevents_register_device(evt);
 235 }
 236 #endif /* CONFIG_TICKSOURCE_GPTMR0 */
 237
 238 #if defined(CONFIG_TICKSOURCE_CORETMR)
 239 /* per-cpu local core timer */
 240 DEFINE_PER_CPU(struct clock_event_device, coretmr_events);
 241
 242 static int bfin_coretmr_set_next_event(unsigned long cycles,
 243                                 struct clock_event_device *evt)
 244 {
 245         bfin_write_TCNTL(TMPWR);
 246         CSYNC();
 247         bfin_write_TCOUNT(cycles);
 248         CSYNC();
 249         bfin_write_TCNTL(TMPWR | TMREN);
 250         return 0;
 251 }
 252
 253 static void bfin_coretmr_set_mode(enum clock_event_mode mode,
 254                                 struct clock_event_device *evt)
 255 {
 256         switch (mode) {
 257         case CLOCK_EVT_MODE_PERIODIC: {
 258                 unsigned long tcount = ((get_cclk() / (HZ * TIME_SCALE)) - 1);
 259                 bfin_write_TCNTL(TMPWR);
 260                 CSYNC();
 261                 bfin_write_TSCALE(TIME_SCALE - 1);
 262                 bfin_write_TPERIOD(tcount);
 263                 bfin_write_TCOUNT(tcount);
 264                 CSYNC();
 265                 bfin_write_TCNTL(TMPWR | TMREN | TAUTORLD);
 266                 break;
 267         }
 268         case CLOCK_EVT_MODE_ONESHOT:
 269                 bfin_write_TCNTL(TMPWR);
 270                 CSYNC();
 271                 bfin_write_TSCALE(TIME_SCALE - 1);
 272                 bfin_write_TPERIOD(0);
 273                 bfin_write_TCOUNT(0);
 274                 break;
 275         case CLOCK_EVT_MODE_UNUSED:
 276         case CLOCK_EVT_MODE_SHUTDOWN:
 277                 bfin_write_TCNTL(0);
 278                 CSYNC();
 279                 break;
 280         case CLOCK_EVT_MODE_RESUME:
 281                 break;
 282         }
 283 }
 284
 285 void bfin_coretmr_init(void)
 286 {
 287         /* power up the timer, but don't enable it just yet */
 288         bfin_write_TCNTL(TMPWR);
 289         CSYNC();
 290
 291         /* the TSCALE prescaler counter. */
 292         bfin_write_TSCALE(TIME_SCALE - 1);
 293         bfin_write_TPERIOD(0);
 294         bfin_write_TCOUNT(0);
 295
 296         CSYNC();
 297 }
 298
 299 #ifdef CONFIG_CORE_TIMER_IRQ_L1
 300 __attribute__((l1_text))
 301 #endif
 302
 303 irqreturn_t bfin_coretmr_interrupt(int irq, void *dev_id)
 304 {
 305         int cpu = smp_processor_id();
 306         struct clock_event_device *evt = &per_cpu(coretmr_events, cpu);
 307
 308         smp_mb();
 309         evt->event_handler(evt);
 310
 311         touch_nmi_watchdog();
 312
 313         return IRQ_HANDLED;
 314 }
 315
 316 static struct irqaction coretmr_irq = {
 317         .name           = "Blackfin CoreTimer",
 318         .flags          = IRQF_TIMER | IRQF_IRQPOLL | IRQF_PERCPU,
 319         .handler        = bfin_coretmr_interrupt,
 320 };
 321
 322 void bfin_coretmr_clockevent_init(void)
 323 {
 324         unsigned long clock_tick;
 325         unsigned int cpu = smp_processor_id();
 326         struct clock_event_device *evt = &per_cpu(coretmr_events, cpu);
 327
 328 #ifdef CONFIG_SMP
 329         evt->broadcast = smp_timer_broadcast;
 330 #endif
 331
 332         evt->name = "bfin_core_timer";
 333         evt->rating = 350;
 334         evt->irq = -1;
 335         evt->shift = 32;
 336         evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 337         evt->set_next_event = bfin_coretmr_set_next_event;
 338         evt->set_mode = bfin_coretmr_set_mode;
 339
 340         clock_tick = get_cclk() / TIME_SCALE;
 341         evt->mult = div_sc(clock_tick, NSEC_PER_SEC, evt->shift);
 342         evt->max_delta_ns = clockevent_delta2ns(-1, evt);
 343         evt->min_delta_ns = clockevent_delta2ns(100, evt);
 344
 345         evt->cpumask = cpumask_of(cpu);
 346
 347         clockevents_register_device(evt);
 348 }
 349 #endif /* CONFIG_TICKSOURCE_CORETMR */
 350
 351
 352 void read_persistent_clock(struct timespec *ts)
 353 {
 354         time_t secs_since_1970 = (365 * 37 + 9) * 24 * 60 * 60; /* 1 Jan 2007 */
 355         ts->tv_sec = secs_since_1970;
 356         ts->tv_nsec = 0;
 357 }
 358
 359 void __init time_init(void)
 360 {
 361
 362 #ifdef CONFIG_RTC_DRV_BFIN
 363         /* [#2663] hack to filter junk RTC values that would cause
 364          * userspace to have to deal with time values greater than
 365          * 2^31 seconds (which uClibc cannot cope with yet)
 366          */
 367         if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) {
 368                 printk(KERN_NOTICE "bfin-rtc: invalid date; resetting\n");
 369                 bfin_write_RTC_STAT(0);
 370         }
 371 #endif
 372
 373         bfin_cs_cycles_init();
 374         bfin_cs_gptimer0_init();
 375
 376 #if defined(CONFIG_TICKSOURCE_CORETMR)
 377         bfin_coretmr_init();
 378         setup_irq(IRQ_CORETMR, &coretmr_irq);
 379         bfin_coretmr_clockevent_init();
 380 #endif
 381
 382 #if defined(CONFIG_TICKSOURCE_GPTMR0)
 383         bfin_gptmr0_init();
 384         setup_irq(IRQ_TIMER0, &gptmr0_irq);
 385         gptmr0_irq.dev_id = &clockevent_gptmr0;
 386         bfin_gptmr0_clockevent_init(&clockevent_gptmr0);
 387 #endif
 388
 389 #if !defined(CONFIG_TICKSOURCE_CORETMR) && !defined(CONFIG_TICKSOURCE_GPTMR0)
 390 # error at least one clock event device is required
 391 #endif
 392 }