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
  23 #include <asm/hardware/gic.h>
  24
  25 #include <plat/cpu.h>
  26
  27 #include <mach/map.h>
  28 #include <mach/irqs.h>
  29 #include <mach/regs-mct.h>
  30 #include <asm/mach/time.h>
  31
  32 enum {
  33         MCT_INT_SPI,
  34         MCT_INT_PPI
  35 };
  36
  37 static unsigned long clk_cnt_per_tick;
  38 static unsigned long clk_rate;
  39 static unsigned int mct_int_type;
  40
  41 struct mct_clock_event_device {
  42         struct clock_event_device *evt;
  43         void __iomem *base;
  44         char name[10];
  45 };
  46
  47 static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
  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         exynos4_mct_comp0_stop();
 211
 212         switch (mode) {
 213         case CLOCK_EVT_MODE_PERIODIC:
 214                 exynos4_mct_comp0_start(mode, clk_cnt_per_tick);
 215                 break;
 216
 217         case CLOCK_EVT_MODE_ONESHOT:
 218         case CLOCK_EVT_MODE_UNUSED:
 219         case CLOCK_EVT_MODE_SHUTDOWN:
 220         case CLOCK_EVT_MODE_RESUME:
 221                 break;
 222         }
 223 }
 224
 225 static struct clock_event_device mct_comp_device = {
 226         .name           = "mct-comp",
 227         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 228         .rating         = 250,
 229         .set_next_event = exynos4_comp_set_next_event,
 230         .set_mode       = exynos4_comp_set_mode,
 231 };
 232
 233 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
 234 {
 235         struct clock_event_device *evt = dev_id;
 236
 237         exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
 238
 239         evt->event_handler(evt);
 240
 241         return IRQ_HANDLED;
 242 }
 243
 244 static struct irqaction mct_comp_event_irq = {
 245         .name           = "mct_comp_irq",
 246         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 247         .handler        = exynos4_mct_comp_isr,
 248         .dev_id         = &mct_comp_device,
 249 };
 250
 251 static void exynos4_clockevent_init(void)
 252 {
 253         clk_cnt_per_tick = clk_rate / 2 / HZ;
 254
 255         clockevents_calc_mult_shift(&mct_comp_device, clk_rate / 2, 5);
 256         mct_comp_device.max_delta_ns =
 257                 clockevent_delta2ns(0xffffffff, &mct_comp_device);
 258         mct_comp_device.min_delta_ns =
 259                 clockevent_delta2ns(0xf, &mct_comp_device);
 260         mct_comp_device.cpumask = cpumask_of(0);
 261         clockevents_register_device(&mct_comp_device);
 262
 263         setup_irq(IRQ_MCT_G0, &mct_comp_event_irq);
 264 }
 265
 266 #ifdef CONFIG_LOCAL_TIMERS
 267 /* Clock event handling */
 268 static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
 269 {
 270         unsigned long tmp;
 271         unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
 272         void __iomem *addr = mevt->base + MCT_L_TCON_OFFSET;
 273
 274         tmp = __raw_readl(addr);
 275         if (tmp & mask) {
 276                 tmp &= ~mask;
 277                 exynos4_mct_write(tmp, addr);
 278         }
 279 }
 280
 281 static void exynos4_mct_tick_start(unsigned long cycles,
 282                                    struct mct_clock_event_device *mevt)
 283 {
 284         unsigned long tmp;
 285
 286         exynos4_mct_tick_stop(mevt);
 287
 288         tmp = (1 << 31) | cycles;       /* MCT_L_UPDATE_ICNTB */
 289
 290         /* update interrupt count buffer */
 291         exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
 292
 293         /* enable MCT tick interrupt */
 294         exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
 295
 296         tmp = __raw_readl(mevt->base + MCT_L_TCON_OFFSET);
 297         tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
 298                MCT_L_TCON_INTERVAL_MODE;
 299         exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
 300 }
 301
 302 static int exynos4_tick_set_next_event(unsigned long cycles,
 303                                        struct clock_event_device *evt)
 304 {
 305         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
 306
 307         exynos4_mct_tick_start(cycles, mevt);
 308
 309         return 0;
 310 }
 311
 312 static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
 313                                          struct clock_event_device *evt)
 314 {
 315         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
 316
 317         exynos4_mct_tick_stop(mevt);
 318
 319         switch (mode) {
 320         case CLOCK_EVT_MODE_PERIODIC:
 321                 exynos4_mct_tick_start(clk_cnt_per_tick, mevt);
 322                 break;
 323
 324         case CLOCK_EVT_MODE_ONESHOT:
 325         case CLOCK_EVT_MODE_UNUSED:
 326         case CLOCK_EVT_MODE_SHUTDOWN:
 327         case CLOCK_EVT_MODE_RESUME:
 328                 break;
 329         }
 330 }
 331
 332 static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
 333 {
 334         struct clock_event_device *evt = mevt->evt;
 335
 336         /*
 337          * This is for supporting oneshot mode.
 338          * Mct would generate interrupt periodically
 339          * without explicit stopping.
 340          */
 341         if (evt->mode != CLOCK_EVT_MODE_PERIODIC)
 342                 exynos4_mct_tick_stop(mevt);
 343
 344         /* Clear the MCT tick interrupt */
 345         if (__raw_readl(mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1) {
 346                 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
 347                 return 1;
 348         } else {
 349                 return 0;
 350         }
 351 }
 352
 353 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
 354 {
 355         struct mct_clock_event_device *mevt = dev_id;
 356         struct clock_event_device *evt = mevt->evt;
 357
 358         exynos4_mct_tick_clear(mevt);
 359
 360         evt->event_handler(evt);
 361
 362         return IRQ_HANDLED;
 363 }
 364
 365 static struct irqaction mct_tick0_event_irq = {
 366         .name           = "mct_tick0_irq",
 367         .flags          = IRQF_TIMER | IRQF_NOBALANCING,
 368         .handler        = exynos4_mct_tick_isr,
 369 };
 370
 371 static struct irqaction mct_tick1_event_irq = {
 372         .name           = "mct_tick1_irq",
 373         .flags          = IRQF_TIMER | IRQF_NOBALANCING,
 374         .handler        = exynos4_mct_tick_isr,
 375 };
 376
 377 static void exynos4_mct_tick_init(struct clock_event_device *evt)
 378 {
 379         struct mct_clock_event_device *mevt;
 380         unsigned int cpu = smp_processor_id();
 381
 382         mevt = this_cpu_ptr(&percpu_mct_tick);
 383         mevt->evt = evt;
 384
 385         mevt->base = EXYNOS4_MCT_L_BASE(cpu);
 386         sprintf(mevt->name, "mct_tick%d", cpu);
 387
 388         evt->name = mevt->name;
 389         evt->cpumask = cpumask_of(cpu);
 390         evt->set_next_event = exynos4_tick_set_next_event;
 391         evt->set_mode = exynos4_tick_set_mode;
 392         evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 393         evt->rating = 450;
 394
 395         clockevents_calc_mult_shift(evt, clk_rate / 2, 5);
 396         evt->max_delta_ns =
 397                 clockevent_delta2ns(0x7fffffff, evt);
 398         evt->min_delta_ns =
 399                 clockevent_delta2ns(0xf, evt);
 400
 401         clockevents_register_device(evt);
 402
 403         exynos4_mct_write(0x1, mevt->base + MCT_L_TCNTB_OFFSET);
 404
 405         if (mct_int_type == MCT_INT_SPI) {
 406                 if (cpu == 0) {
 407                         mct_tick0_event_irq.dev_id = mevt;
 408                         evt->irq = IRQ_MCT_L0;
 409                         setup_irq(IRQ_MCT_L0, &mct_tick0_event_irq);
 410                 } else {
 411                         mct_tick1_event_irq.dev_id = mevt;
 412                         evt->irq = IRQ_MCT_L1;
 413                         setup_irq(IRQ_MCT_L1, &mct_tick1_event_irq);
 414                         irq_set_affinity(IRQ_MCT_L1, cpumask_of(1));
 415                 }
 416         } else {
 417                 enable_percpu_irq(IRQ_MCT_LOCALTIMER, 0);
 418         }
 419 }
 420
 421 /* Setup the local clock events for a CPU */
 422 int __cpuinit local_timer_setup(struct clock_event_device *evt)
 423 {
 424         exynos4_mct_tick_init(evt);
 425
 426         return 0;
 427 }
 428
 429 void local_timer_stop(struct clock_event_device *evt)
 430 {
 431         evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
 432         if (mct_int_type == MCT_INT_SPI)
 433                 disable_irq(evt->irq);
 434         else
 435                 disable_percpu_irq(IRQ_MCT_LOCALTIMER);
 436 }
 437 #endif /* CONFIG_LOCAL_TIMERS */
 438
 439 static void __init exynos4_timer_resources(void)
 440 {
 441         struct clk *mct_clk;
 442         mct_clk = clk_get(NULL, "xtal");
 443
 444         clk_rate = clk_get_rate(mct_clk);
 445
 446         if (mct_int_type == MCT_INT_PPI) {
 447                 int err;
 448
 449                 err = request_percpu_irq(IRQ_MCT_LOCALTIMER,
 450                                          exynos4_mct_tick_isr, "MCT",
 451                                          &percpu_mct_tick);
 452                 WARN(err, "MCT: can't request IRQ %d (%d)\n",
 453                      IRQ_MCT_LOCALTIMER, err);
 454         }
 455 }
 456
 457 static void __init exynos4_timer_init(void)
 458 {
 459         if (soc_is_exynos4210())
 460                 mct_int_type = MCT_INT_SPI;
 461         else
 462                 mct_int_type = MCT_INT_PPI;
 463
 464         exynos4_timer_resources();
 465         exynos4_clocksource_init();
 466         exynos4_clockevent_init();
 467 }
 468
 469 struct sys_timer exynos4_timer = {
 470         .init           = exynos4_timer_init,
 471 };