arch/arm/mach-exynos/mct.c

   1 /* linux/arch/arm/mach-exynos4/mct.c
   2  *
   3  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
   4  *              http://www.samsung.com
   5  *
   6  * EXYNOS4 MCT(Multi-Core Timer) support
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11 */
  12
  13 #include <linux/sched.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irq.h>
  16 #include <linux/err.h>
  17 #include <linux/clk.h>
  18 #include <linux/clockchips.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/delay.h>
  21 #include <linux/percpu.h>
  22 #include <linux/of.h>
  23
  24 #include <asm/localtimer.h>
  25
  26 #include <plat/cpu.h>
  27
  28 #include <mach/map.h>
  29 #include <mach/irqs.h>
  30 #include <mach/regs-mct.h>
  31 #include <asm/mach/time.h>
  32
  33 #define TICK_BASE_CNT   1
  34
  35 enum {
  36         MCT_INT_SPI,
  37         MCT_INT_PPI
  38 };
  39
  40 static unsigned long clk_rate;
  41 static unsigned int mct_int_type;
  42
  43 struct mct_clock_event_device {
  44         struct clock_event_device *evt;
  45         void __iomem *base;
  46         char name[10];
  47 };
  48
  49 static void exynos4_mct_write(unsigned int value, void *addr)
  50 {
  51         void __iomem *stat_addr;
  52         u32 mask;
  53         u32 i;
  54
  55         __raw_writel(value, addr);
  56
  57         if (likely(addr >= EXYNOS4_MCT_L_BASE(0))) {
  58                 u32 base = (u32) addr & EXYNOS4_MCT_L_MASK;
  59                 switch ((u32) addr & ~EXYNOS4_MCT_L_MASK) {
  60                 case (u32) MCT_L_TCON_OFFSET:
  61                         stat_addr = (void __iomem *) base + MCT_L_WSTAT_OFFSET;
  62                         mask = 1 << 3;          /* L_TCON write status */
  63                         break;
  64                 case (u32) MCT_L_ICNTB_OFFSET:
  65                         stat_addr = (void __iomem *) base + MCT_L_WSTAT_OFFSET;
  66                         mask = 1 << 1;          /* L_ICNTB write status */
  67                         break;
  68                 case (u32) MCT_L_TCNTB_OFFSET:
  69                         stat_addr = (void __iomem *) base + MCT_L_WSTAT_OFFSET;
  70                         mask = 1 << 0;          /* L_TCNTB write status */
  71                         break;
  72                 default:
  73                         return;
  74                 }
  75         } else {
  76                 switch ((u32) addr) {
  77                 case (u32) EXYNOS4_MCT_G_TCON:
  78                         stat_addr = EXYNOS4_MCT_G_WSTAT;
  79                         mask = 1 << 16;         /* G_TCON write status */
  80                         break;
  81                 case (u32) EXYNOS4_MCT_G_COMP0_L:
  82                         stat_addr = EXYNOS4_MCT_G_WSTAT;
  83                         mask = 1 << 0;          /* G_COMP0_L write status */
  84                         break;
  85                 case (u32) EXYNOS4_MCT_G_COMP0_U:
  86                         stat_addr = EXYNOS4_MCT_G_WSTAT;
  87                         mask = 1 << 1;          /* G_COMP0_U write status */
  88                         break;
  89                 case (u32) EXYNOS4_MCT_G_COMP0_ADD_INCR:
  90                         stat_addr = EXYNOS4_MCT_G_WSTAT;
  91                         mask = 1 << 2;          /* G_COMP0_ADD_INCR w status */
  92                         break;
  93                 case (u32) EXYNOS4_MCT_G_CNT_L:
  94                         stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
  95                         mask = 1 << 0;          /* G_CNT_L write status */
  96                         break;
  97                 case (u32) EXYNOS4_MCT_G_CNT_U:
  98                         stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
  99                         mask = 1 << 1;          /* G_CNT_U write status */
 100                         break;
 101                 default:
 102                         return;
 103                 }
 104         }
 105
 106         /* Wait maximum 1 ms until written values are applied */
 107         for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
 108                 if (__raw_readl(stat_addr) & mask) {
 109                         __raw_writel(mask, stat_addr);
 110                         return;
 111                 }
 112
 113         panic("MCT hangs after writing %d (addr:0x%08x)\n", value, (u32)addr);
 114 }
 115
 116 /* Clocksource handling */
 117 static void exynos4_mct_frc_start(u32 hi, u32 lo)
 118 {
 119         u32 reg;
 120
 121         exynos4_mct_write(lo, EXYNOS4_MCT_G_CNT_L);
 122         exynos4_mct_write(hi, EXYNOS4_MCT_G_CNT_U);
 123
 124         reg = __raw_readl(EXYNOS4_MCT_G_TCON);
 125         reg |= MCT_G_TCON_START;
 126         exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
 127 }
 128
 129 static cycle_t exynos4_frc_read(struct clocksource *cs)
 130 {
 131         unsigned int lo, hi;
 132         u32 hi2 = __raw_readl(EXYNOS4_MCT_G_CNT_U);
 133
 134         do {
 135                 hi = hi2;
 136                 lo = __raw_readl(EXYNOS4_MCT_G_CNT_L);
 137                 hi2 = __raw_readl(EXYNOS4_MCT_G_CNT_U);
 138         } while (hi != hi2);
 139
 140         return ((cycle_t)hi << 32) | lo;
 141 }
 142
 143 static void exynos4_frc_resume(struct clocksource *cs)
 144 {
 145         exynos4_mct_frc_start(0, 0);
 146 }
 147
 148 struct clocksource mct_frc = {
 149         .name           = "mct-frc",
 150         .rating         = 400,
 151         .read           = exynos4_frc_read,
 152         .mask           = CLOCKSOURCE_MASK(64),
 153         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 154         .resume         = exynos4_frc_resume,
 155 };
 156
 157 static void __init exynos4_clocksource_init(void)
 158 {
 159         exynos4_mct_frc_start(0, 0);
 160
 161         if (clocksource_register_hz(&mct_frc, clk_rate))
 162                 panic("%s: can't register clocksource\n", mct_frc.name);
 163 }
 164
 165 static void exynos4_mct_comp0_stop(void)
 166 {
 167         unsigned int tcon;
 168
 169         tcon = __raw_readl(EXYNOS4_MCT_G_TCON);
 170         tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
 171
 172         exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
 173         exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
 174 }
 175
 176 static void exynos4_mct_comp0_start(enum clock_event_mode mode,
 177                                     unsigned long cycles)
 178 {
 179         unsigned int tcon;
 180         cycle_t comp_cycle;
 181
 182         tcon = __raw_readl(EXYNOS4_MCT_G_TCON);
 183
 184         if (mode == CLOCK_EVT_MODE_PERIODIC) {
 185                 tcon |= MCT_G_TCON_COMP0_AUTO_INC;
 186                 exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
 187         }
 188
 189         comp_cycle = exynos4_frc_read(&mct_frc) + cycles;
 190         exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
 191         exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
 192
 193         exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
 194
 195         tcon |= MCT_G_TCON_COMP0_ENABLE;
 196         exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
 197 }
 198
 199 static int exynos4_comp_set_next_event(unsigned long cycles,
 200                                        struct clock_event_device *evt)
 201 {
 202         exynos4_mct_comp0_start(evt->mode, cycles);
 203
 204         return 0;
 205 }
 206
 207 static void exynos4_comp_set_mode(enum clock_event_mode mode,
 208                                   struct clock_event_device *evt)
 209 {
 210         unsigned long cycles_per_jiffy;
 211         exynos4_mct_comp0_stop();
 212
 213         switch (mode) {
 214         case CLOCK_EVT_MODE_PERIODIC:
 215                 cycles_per_jiffy =
 216                         (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
 217                 exynos4_mct_comp0_start(mode, cycles_per_jiffy);
 218                 break;
 219
 220         case CLOCK_EVT_MODE_ONESHOT:
 221         case CLOCK_EVT_MODE_UNUSED:
 222         case CLOCK_EVT_MODE_SHUTDOWN:
 223         case CLOCK_EVT_MODE_RESUME:
 224                 break;
 225         }
 226 }
 227
 228 static struct clock_event_device mct_comp_device = {
 229         .name           = "mct-comp",
 230         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 231         .rating         = 250,
 232         .set_next_event = exynos4_comp_set_next_event,
 233         .set_mode       = exynos4_comp_set_mode,
 234 };
 235
 236 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
 237 {
 238         struct clock_event_device *evt = dev_id;
 239
 240         exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
 241
 242         evt->event_handler(evt);
 243
 244         return IRQ_HANDLED;
 245 }
 246
 247 static struct irqaction mct_comp_event_irq = {
 248         .name           = "mct_comp_irq",
 249         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 250         .handler        = exynos4_mct_comp_isr,
 251         .dev_id         = &mct_comp_device,
 252 };
 253
 254 static void exynos4_clockevent_init(void)
 255 {
 256         mct_comp_device.cpumask = cpumask_of(0);
 257         clockevents_config_and_register(&mct_comp_device, clk_rate,
 258                                         0xf, 0xffffffff);
 259
 260         if (soc_is_exynos5250())
 261                 setup_irq(EXYNOS5_IRQ_MCT_G0, &mct_comp_event_irq);
 262         else
 263                 setup_irq(EXYNOS4_IRQ_MCT_G0, &mct_comp_event_irq);
 264 }
 265
 266 #ifdef CONFIG_LOCAL_TIMERS
 267
 268 static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
 269
 270 /* Clock event handling */
 271 static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
 272 {
 273         unsigned long tmp;
 274         unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
 275         void __iomem *addr = mevt->base + MCT_L_TCON_OFFSET;
 276
 277         tmp = __raw_readl(addr);
 278         if (tmp & mask) {
 279                 tmp &= ~mask;
 280                 exynos4_mct_write(tmp, addr);
 281         }
 282 }
 283
 284 static void exynos4_mct_tick_start(unsigned long cycles,
 285                                    struct mct_clock_event_device *mevt)
 286 {
 287         unsigned long tmp;
 288
 289         exynos4_mct_tick_stop(mevt);
 290
 291         tmp = (1 << 31) | cycles;       /* MCT_L_UPDATE_ICNTB */
 292
 293         /* update interrupt count buffer */
 294         exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
 295
 296         /* enable MCT tick interrupt */
 297         exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
 298
 299         tmp = __raw_readl(mevt->base + MCT_L_TCON_OFFSET);
 300         tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
 301                MCT_L_TCON_INTERVAL_MODE;
 302         exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
 303 }
 304
 305 static int exynos4_tick_set_next_event(unsigned long cycles,
 306                                        struct clock_event_device *evt)
 307 {
 308         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
 309
 310         exynos4_mct_tick_start(cycles, mevt);
 311
 312         return 0;
 313 }
 314
 315 static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
 316                                          struct clock_event_device *evt)
 317 {
 318         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
 319         unsigned long cycles_per_jiffy;
 320
 321         exynos4_mct_tick_stop(mevt);
 322
 323         switch (mode) {
 324         case CLOCK_EVT_MODE_PERIODIC:
 325                 cycles_per_jiffy =
 326                         (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
 327                 exynos4_mct_tick_start(cycles_per_jiffy, mevt);
 328                 break;
 329
 330         case CLOCK_EVT_MODE_ONESHOT:
 331         case CLOCK_EVT_MODE_UNUSED:
 332         case CLOCK_EVT_MODE_SHUTDOWN:
 333         case CLOCK_EVT_MODE_RESUME:
 334                 break;
 335         }
 336 }
 337
 338 static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
 339 {
 340         struct clock_event_device *evt = mevt->evt;
 341
 342         /*
 343          * This is for supporting oneshot mode.
 344          * Mct would generate interrupt periodically
 345          * without explicit stopping.
 346          */
 347         if (evt->mode != CLOCK_EVT_MODE_PERIODIC)
 348                 exynos4_mct_tick_stop(mevt);
 349
 350         /* Clear the MCT tick interrupt */
 351         if (__raw_readl(mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1) {
 352                 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
 353                 return 1;
 354         } else {
 355                 return 0;
 356         }
 357 }
 358
 359 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
 360 {
 361         struct mct_clock_event_device *mevt = dev_id;
 362         struct clock_event_device *evt = mevt->evt;
 363
 364         exynos4_mct_tick_clear(mevt);
 365
 366         evt->event_handler(evt);
 367
 368         return IRQ_HANDLED;
 369 }
 370
 371 static struct irqaction mct_tick0_event_irq = {
 372         .name           = "mct_tick0_irq",
 373         .flags          = IRQF_TIMER | IRQF_NOBALANCING,
 374         .handler        = exynos4_mct_tick_isr,
 375 };
 376
 377 static struct irqaction mct_tick1_event_irq = {
 378         .name           = "mct_tick1_irq",
 379         .flags          = IRQF_TIMER | IRQF_NOBALANCING,
 380         .handler        = exynos4_mct_tick_isr,
 381 };
 382
 383 static int __cpuinit exynos4_local_timer_setup(struct clock_event_device *evt)
 384 {
 385         struct mct_clock_event_device *mevt;
 386         unsigned int cpu = smp_processor_id();
 387         int mct_lx_irq;
 388
 389         mevt = this_cpu_ptr(&percpu_mct_tick);
 390         mevt->evt = evt;
 391
 392         mevt->base = EXYNOS4_MCT_L_BASE(cpu);
 393         sprintf(mevt->name, "mct_tick%d", cpu);
 394
 395         evt->name = mevt->name;
 396         evt->cpumask = cpumask_of(cpu);
 397         evt->set_next_event = exynos4_tick_set_next_event;
 398         evt->set_mode = exynos4_tick_set_mode;
 399         evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 400         evt->rating = 450;
 401         clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
 402                                         0xf, 0x7fffffff);
 403
 404         exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
 405
 406         if (mct_int_type == MCT_INT_SPI) {
 407                 if (cpu == 0) {
 408                         mct_lx_irq = soc_is_exynos4210() ? EXYNOS4_IRQ_MCT_L0 :
 409                                                 EXYNOS5_IRQ_MCT_L0;
 410                         mct_tick0_event_irq.dev_id = mevt;
 411                         evt->irq = mct_lx_irq;
 412                         setup_irq(mct_lx_irq, &mct_tick0_event_irq);
 413                 } else {
 414                         mct_lx_irq = soc_is_exynos4210() ? EXYNOS4_IRQ_MCT_L1 :
 415                                                 EXYNOS5_IRQ_MCT_L1;
 416                         mct_tick1_event_irq.dev_id = mevt;
 417                         evt->irq = mct_lx_irq;
 418                         setup_irq(mct_lx_irq, &mct_tick1_event_irq);
 419                         irq_set_affinity(mct_lx_irq, cpumask_of(1));
 420                 }
 421         } else {
 422                 enable_percpu_irq(EXYNOS_IRQ_MCT_LOCALTIMER, 0);
 423         }
 424
 425         return 0;
 426 }
 427
 428 static void exynos4_local_timer_stop(struct clock_event_device *evt)
 429 {
 430         unsigned int cpu = smp_processor_id();
 431         evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
 432         if (mct_int_type == MCT_INT_SPI)
 433                 if (cpu == 0)
 434                         remove_irq(evt->irq, &mct_tick0_event_irq);
 435                 else
 436                         remove_irq(evt->irq, &mct_tick1_event_irq);
 437         else
 438                 disable_percpu_irq(EXYNOS_IRQ_MCT_LOCALTIMER);
 439 }
 440
 441 static struct local_timer_ops exynos4_mct_tick_ops __cpuinitdata = {
 442         .setup  = exynos4_local_timer_setup,
 443         .stop   = exynos4_local_timer_stop,
 444 };
 445 #endif /* CONFIG_LOCAL_TIMERS */
 446
 447 static void __init exynos4_timer_resources(void)
 448 {
 449         struct clk *mct_clk;
 450         mct_clk = clk_get(NULL, "xtal");
 451
 452         clk_rate = clk_get_rate(mct_clk);
 453
 454 #ifdef CONFIG_LOCAL_TIMERS
 455         if (mct_int_type == MCT_INT_PPI) {
 456                 int err;
 457
 458                 err = request_percpu_irq(EXYNOS_IRQ_MCT_LOCALTIMER,
 459                                          exynos4_mct_tick_isr, "MCT",
 460                                          &percpu_mct_tick);
 461                 WARN(err, "MCT: can't request IRQ %d (%d)\n",
 462                      EXYNOS_IRQ_MCT_LOCALTIMER, err);
 463         }
 464
 465         local_timer_register(&exynos4_mct_tick_ops);
 466 #endif /* CONFIG_LOCAL_TIMERS */
 467 }
 468
 469 void __init exynos4_timer_init(void)
 470 {
 471         if ((soc_is_exynos4210()) || (soc_is_exynos5250()))
 472                 mct_int_type = MCT_INT_SPI;
 473         else
 474                 mct_int_type = MCT_INT_PPI;
 475
 476         exynos4_timer_resources();
 477         exynos4_clocksource_init();
 478         exynos4_clockevent_init();
 479 }