drivers/clocksource/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 #include <linux/of_irq.h>
  24 #include <linux/of_address.h>
  25 #include <linux/clocksource.h>
  26
  27 #include <asm/localtimer.h>
  28 #include <asm/mach/time.h>
  29
  30 #define EXYNOS4_MCTREG(x)               (x)
  31 #define EXYNOS4_MCT_G_CNT_L             EXYNOS4_MCTREG(0x100)
  32 #define EXYNOS4_MCT_G_CNT_U             EXYNOS4_MCTREG(0x104)
  33 #define EXYNOS4_MCT_G_CNT_WSTAT         EXYNOS4_MCTREG(0x110)
  34 #define EXYNOS4_MCT_G_COMP0_L           EXYNOS4_MCTREG(0x200)
  35 #define EXYNOS4_MCT_G_COMP0_U           EXYNOS4_MCTREG(0x204)
  36 #define EXYNOS4_MCT_G_COMP0_ADD_INCR    EXYNOS4_MCTREG(0x208)
  37 #define EXYNOS4_MCT_G_TCON              EXYNOS4_MCTREG(0x240)
  38 #define EXYNOS4_MCT_G_INT_CSTAT         EXYNOS4_MCTREG(0x244)
  39 #define EXYNOS4_MCT_G_INT_ENB           EXYNOS4_MCTREG(0x248)
  40 #define EXYNOS4_MCT_G_WSTAT             EXYNOS4_MCTREG(0x24C)
  41 #define _EXYNOS4_MCT_L_BASE             EXYNOS4_MCTREG(0x300)
  42 #define EXYNOS4_MCT_L_BASE(x)           (_EXYNOS4_MCT_L_BASE + (0x100 * x))
  43 #define EXYNOS4_MCT_L_MASK              (0xffffff00)
  44
  45 #define MCT_L_TCNTB_OFFSET              (0x00)
  46 #define MCT_L_ICNTB_OFFSET              (0x08)
  47 #define MCT_L_TCON_OFFSET               (0x20)
  48 #define MCT_L_INT_CSTAT_OFFSET          (0x30)
  49 #define MCT_L_INT_ENB_OFFSET            (0x34)
  50 #define MCT_L_WSTAT_OFFSET              (0x40)
  51 #define MCT_G_TCON_START                (1 << 8)
  52 #define MCT_G_TCON_COMP0_AUTO_INC       (1 << 1)
  53 #define MCT_G_TCON_COMP0_ENABLE         (1 << 0)
  54 #define MCT_L_TCON_INTERVAL_MODE        (1 << 2)
  55 #define MCT_L_TCON_INT_START            (1 << 1)
  56 #define MCT_L_TCON_TIMER_START          (1 << 0)
  57
  58 #define TICK_BASE_CNT   1
  59
  60 enum {
  61         MCT_INT_SPI,
  62         MCT_INT_PPI
  63 };
  64
  65 enum {
  66         MCT_G0_IRQ,
  67         MCT_G1_IRQ,
  68         MCT_G2_IRQ,
  69         MCT_G3_IRQ,
  70         MCT_L0_IRQ,
  71         MCT_L1_IRQ,
  72         MCT_L2_IRQ,
  73         MCT_L3_IRQ,
  74         MCT_NR_IRQS,
  75 };
  76
  77 static void __iomem *reg_base;
  78 static unsigned long clk_rate;
  79 static unsigned int mct_int_type;
  80 static int mct_irqs[MCT_NR_IRQS];
  81
  82 struct mct_clock_event_device {
  83         struct clock_event_device *evt;
  84         unsigned long base;
  85         char name[10];
  86 };
  87
  88 static void exynos4_mct_write(unsigned int value, unsigned long offset)
  89 {
  90         unsigned long stat_addr;
  91         u32 mask;
  92         u32 i;
  93
  94         __raw_writel(value, reg_base + offset);
  95
  96         if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) {
  97                 stat_addr = (offset & ~EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET;
  98                 switch (offset & EXYNOS4_MCT_L_MASK) {
  99                 case MCT_L_TCON_OFFSET:
 100                         mask = 1 << 3;          /* L_TCON write status */
 101                         break;
 102                 case MCT_L_ICNTB_OFFSET:
 103                         mask = 1 << 1;          /* L_ICNTB write status */
 104                         break;
 105                 case MCT_L_TCNTB_OFFSET:
 106                         mask = 1 << 0;          /* L_TCNTB write status */
 107                         break;
 108                 default:
 109                         return;
 110                 }
 111         } else {
 112                 switch (offset) {
 113                 case EXYNOS4_MCT_G_TCON:
 114                         stat_addr = EXYNOS4_MCT_G_WSTAT;
 115                         mask = 1 << 16;         /* G_TCON write status */
 116                         break;
 117                 case EXYNOS4_MCT_G_COMP0_L:
 118                         stat_addr = EXYNOS4_MCT_G_WSTAT;
 119                         mask = 1 << 0;          /* G_COMP0_L write status */
 120                         break;
 121                 case EXYNOS4_MCT_G_COMP0_U:
 122                         stat_addr = EXYNOS4_MCT_G_WSTAT;
 123                         mask = 1 << 1;          /* G_COMP0_U write status */
 124                         break;
 125                 case EXYNOS4_MCT_G_COMP0_ADD_INCR:
 126                         stat_addr = EXYNOS4_MCT_G_WSTAT;
 127                         mask = 1 << 2;          /* G_COMP0_ADD_INCR w status */
 128                         break;
 129                 case EXYNOS4_MCT_G_CNT_L:
 130                         stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
 131                         mask = 1 << 0;          /* G_CNT_L write status */
 132                         break;
 133                 case EXYNOS4_MCT_G_CNT_U:
 134                         stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
 135                         mask = 1 << 1;          /* G_CNT_U write status */
 136                         break;
 137                 default:
 138                         return;
 139                 }
 140         }
 141
 142         /* Wait maximum 1 ms until written values are applied */
 143         for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
 144                 if (__raw_readl(reg_base + stat_addr) & mask) {
 145                         __raw_writel(mask, reg_base + stat_addr);
 146                         return;
 147                 }
 148
 149         panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset);
 150 }
 151
 152 /* Clocksource handling */
 153 static void exynos4_mct_frc_start(u32 hi, u32 lo)
 154 {
 155         u32 reg;
 156
 157         exynos4_mct_write(lo, EXYNOS4_MCT_G_CNT_L);
 158         exynos4_mct_write(hi, EXYNOS4_MCT_G_CNT_U);
 159
 160         reg = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
 161         reg |= MCT_G_TCON_START;
 162         exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
 163 }
 164
 165 static cycle_t exynos4_frc_read(struct clocksource *cs)
 166 {
 167         unsigned int lo, hi;
 168         u32 hi2 = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_U);
 169
 170         do {
 171                 hi = hi2;
 172                 lo = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_L);
 173                 hi2 = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_U);
 174         } while (hi != hi2);
 175
 176         return ((cycle_t)hi << 32) | lo;
 177 }
 178
 179 static void exynos4_frc_resume(struct clocksource *cs)
 180 {
 181         exynos4_mct_frc_start(0, 0);
 182 }
 183
 184 struct clocksource mct_frc = {
 185         .name           = "mct-frc",
 186         .rating         = 400,
 187         .read           = exynos4_frc_read,
 188         .mask           = CLOCKSOURCE_MASK(64),
 189         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 190         .resume         = exynos4_frc_resume,
 191 };
 192
 193 static void __init exynos4_clocksource_init(void)
 194 {
 195         exynos4_mct_frc_start(0, 0);
 196
 197         if (clocksource_register_hz(&mct_frc, clk_rate))
 198                 panic("%s: can't register clocksource\n", mct_frc.name);
 199 }
 200
 201 static void exynos4_mct_comp0_stop(void)
 202 {
 203         unsigned int tcon;
 204
 205         tcon = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
 206         tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
 207
 208         exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
 209         exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
 210 }
 211
 212 static void exynos4_mct_comp0_start(enum clock_event_mode mode,
 213                                     unsigned long cycles)
 214 {
 215         unsigned int tcon;
 216         cycle_t comp_cycle;
 217
 218         tcon = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
 219
 220         if (mode == CLOCK_EVT_MODE_PERIODIC) {
 221                 tcon |= MCT_G_TCON_COMP0_AUTO_INC;
 222                 exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
 223         }
 224
 225         comp_cycle = exynos4_frc_read(&mct_frc) + cycles;
 226         exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
 227         exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
 228
 229         exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
 230
 231         tcon |= MCT_G_TCON_COMP0_ENABLE;
 232         exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
 233 }
 234
 235 static int exynos4_comp_set_next_event(unsigned long cycles,
 236                                        struct clock_event_device *evt)
 237 {
 238         exynos4_mct_comp0_start(evt->mode, cycles);
 239
 240         return 0;
 241 }
 242
 243 static void exynos4_comp_set_mode(enum clock_event_mode mode,
 244                                   struct clock_event_device *evt)
 245 {
 246         unsigned long cycles_per_jiffy;
 247         exynos4_mct_comp0_stop();
 248
 249         switch (mode) {
 250         case CLOCK_EVT_MODE_PERIODIC:
 251                 cycles_per_jiffy =
 252                         (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
 253                 exynos4_mct_comp0_start(mode, cycles_per_jiffy);
 254                 break;
 255
 256         case CLOCK_EVT_MODE_ONESHOT:
 257         case CLOCK_EVT_MODE_UNUSED:
 258         case CLOCK_EVT_MODE_SHUTDOWN:
 259         case CLOCK_EVT_MODE_RESUME:
 260                 break;
 261         }
 262 }
 263
 264 static struct clock_event_device mct_comp_device = {
 265         .name           = "mct-comp",
 266         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 267         .rating         = 250,
 268         .set_next_event = exynos4_comp_set_next_event,
 269         .set_mode       = exynos4_comp_set_mode,
 270 };
 271
 272 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
 273 {
 274         struct clock_event_device *evt = dev_id;
 275
 276         exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
 277
 278         evt->event_handler(evt);
 279
 280         return IRQ_HANDLED;
 281 }
 282
 283 static struct irqaction mct_comp_event_irq = {
 284         .name           = "mct_comp_irq",
 285         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 286         .handler        = exynos4_mct_comp_isr,
 287         .dev_id         = &mct_comp_device,
 288 };
 289
 290 static void exynos4_clockevent_init(void)
 291 {
 292         mct_comp_device.cpumask = cpumask_of(0);
 293         clockevents_config_and_register(&mct_comp_device, clk_rate,
 294                                         0xf, 0xffffffff);
 295         setup_irq(mct_irqs[MCT_G0_IRQ], &mct_comp_event_irq);
 296 }
 297
 298 #ifdef CONFIG_LOCAL_TIMERS
 299
 300 static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
 301
 302 /* Clock event handling */
 303 static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
 304 {
 305         unsigned long tmp;
 306         unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
 307         unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
 308
 309         tmp = __raw_readl(reg_base + offset);
 310         if (tmp & mask) {
 311                 tmp &= ~mask;
 312                 exynos4_mct_write(tmp, offset);
 313         }
 314 }
 315
 316 static void exynos4_mct_tick_start(unsigned long cycles,
 317                                    struct mct_clock_event_device *mevt)
 318 {
 319         unsigned long tmp;
 320
 321         exynos4_mct_tick_stop(mevt);
 322
 323         tmp = (1 << 31) | cycles;       /* MCT_L_UPDATE_ICNTB */
 324
 325         /* update interrupt count buffer */
 326         exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
 327
 328         /* enable MCT tick interrupt */
 329         exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
 330
 331         tmp = __raw_readl(reg_base + mevt->base + MCT_L_TCON_OFFSET);
 332         tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
 333                MCT_L_TCON_INTERVAL_MODE;
 334         exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
 335 }
 336
 337 static int exynos4_tick_set_next_event(unsigned long cycles,
 338                                        struct clock_event_device *evt)
 339 {
 340         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
 341
 342         exynos4_mct_tick_start(cycles, mevt);
 343
 344         return 0;
 345 }
 346
 347 static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
 348                                          struct clock_event_device *evt)
 349 {
 350         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
 351         unsigned long cycles_per_jiffy;
 352
 353         exynos4_mct_tick_stop(mevt);
 354
 355         switch (mode) {
 356         case CLOCK_EVT_MODE_PERIODIC:
 357                 cycles_per_jiffy =
 358                         (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
 359                 exynos4_mct_tick_start(cycles_per_jiffy, mevt);
 360                 break;
 361
 362         case CLOCK_EVT_MODE_ONESHOT:
 363         case CLOCK_EVT_MODE_UNUSED:
 364         case CLOCK_EVT_MODE_SHUTDOWN:
 365         case CLOCK_EVT_MODE_RESUME:
 366                 break;
 367         }
 368 }
 369
 370 static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
 371 {
 372         struct clock_event_device *evt = mevt->evt;
 373
 374         /*
 375          * This is for supporting oneshot mode.
 376          * Mct would generate interrupt periodically
 377          * without explicit stopping.
 378          */
 379         if (evt->mode != CLOCK_EVT_MODE_PERIODIC)
 380                 exynos4_mct_tick_stop(mevt);
 381
 382         /* Clear the MCT tick interrupt */
 383         if (__raw_readl(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1) {
 384                 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
 385                 return 1;
 386         } else {
 387                 return 0;
 388         }
 389 }
 390
 391 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
 392 {
 393         struct mct_clock_event_device *mevt = dev_id;
 394         struct clock_event_device *evt = mevt->evt;
 395
 396         exynos4_mct_tick_clear(mevt);
 397
 398         evt->event_handler(evt);
 399
 400         return IRQ_HANDLED;
 401 }
 402
 403 static struct irqaction mct_tick0_event_irq = {
 404         .name           = "mct_tick0_irq",
 405         .flags          = IRQF_TIMER | IRQF_NOBALANCING,
 406         .handler        = exynos4_mct_tick_isr,
 407 };
 408
 409 static struct irqaction mct_tick1_event_irq = {
 410         .name           = "mct_tick1_irq",
 411         .flags          = IRQF_TIMER | IRQF_NOBALANCING,
 412         .handler        = exynos4_mct_tick_isr,
 413 };
 414
 415 static int __cpuinit exynos4_local_timer_setup(struct clock_event_device *evt)
 416 {
 417         struct mct_clock_event_device *mevt;
 418         unsigned int cpu = smp_processor_id();
 419
 420         mevt = this_cpu_ptr(&percpu_mct_tick);
 421         mevt->evt = evt;
 422
 423         mevt->base = EXYNOS4_MCT_L_BASE(cpu);
 424         sprintf(mevt->name, "mct_tick%d", cpu);
 425
 426         evt->name = mevt->name;
 427         evt->cpumask = cpumask_of(cpu);
 428         evt->set_next_event = exynos4_tick_set_next_event;
 429         evt->set_mode = exynos4_tick_set_mode;
 430         evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 431         evt->rating = 450;
 432
 433         exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
 434
 435         if (mct_int_type == MCT_INT_SPI) {
 436                 if (cpu == 0) {
 437                         mct_tick0_event_irq.dev_id = mevt;
 438                         evt->irq = mct_irqs[MCT_L0_IRQ];
 439                         setup_irq(evt->irq, &mct_tick0_event_irq);
 440                 } else {
 441                         mct_tick1_event_irq.dev_id = mevt;
 442                         evt->irq = mct_irqs[MCT_L1_IRQ];
 443                         setup_irq(evt->irq, &mct_tick1_event_irq);
 444                         irq_set_affinity(evt->irq, cpumask_of(1));
 445                 }
 446         } else {
 447                 enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
 448         }
 449         clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
 450                                         0xf, 0x7fffffff);
 451
 452         return 0;
 453 }
 454
 455 static void exynos4_local_timer_stop(struct clock_event_device *evt)
 456 {
 457         unsigned int cpu = smp_processor_id();
 458         evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
 459         if (mct_int_type == MCT_INT_SPI)
 460                 if (cpu == 0)
 461                         remove_irq(evt->irq, &mct_tick0_event_irq);
 462                 else
 463                         remove_irq(evt->irq, &mct_tick1_event_irq);
 464         else
 465                 disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
 466 }
 467
 468 static struct local_timer_ops exynos4_mct_tick_ops __cpuinitdata = {
 469         .setup  = exynos4_local_timer_setup,
 470         .stop   = exynos4_local_timer_stop,
 471 };
 472 #endif /* CONFIG_LOCAL_TIMERS */
 473
 474 static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
 475 {
 476         struct clk *mct_clk, *tick_clk;
 477
 478         tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
 479                                 clk_get(NULL, "fin_pll");
 480         if (IS_ERR(tick_clk))
 481                 panic("%s: unable to determine tick clock rate\n", __func__);
 482         clk_rate = clk_get_rate(tick_clk);
 483
 484         mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct");
 485         if (IS_ERR(mct_clk))
 486                 panic("%s: unable to retrieve mct clock instance\n", __func__);
 487         clk_prepare_enable(mct_clk);
 488
 489         reg_base = base;
 490         if (!reg_base)
 491                 panic("%s: unable to ioremap mct address space\n", __func__);
 492
 493 #ifdef CONFIG_LOCAL_TIMERS
 494         if (mct_int_type == MCT_INT_PPI) {
 495                 int err;
 496
 497                 err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
 498                                          exynos4_mct_tick_isr, "MCT",
 499                                          &percpu_mct_tick);
 500                 WARN(err, "MCT: can't request IRQ %d (%d)\n",
 501                      mct_irqs[MCT_L0_IRQ], err);
 502         }
 503
 504         local_timer_register(&exynos4_mct_tick_ops);
 505 #endif /* CONFIG_LOCAL_TIMERS */
 506 }
 507
 508 void __init mct_init(void __iomem *base, int irq_g0, int irq_l0, int irq_l1)
 509 {
 510         mct_irqs[MCT_G0_IRQ] = irq_g0;
 511         mct_irqs[MCT_L0_IRQ] = irq_l0;
 512         mct_irqs[MCT_L1_IRQ] = irq_l1;
 513         mct_int_type = MCT_INT_SPI;
 514
 515         exynos4_timer_resources(NULL, base);
 516         exynos4_clocksource_init();
 517         exynos4_clockevent_init();
 518 }
 519
 520 static void __init mct_init_dt(struct device_node *np, unsigned int int_type)
 521 {
 522         u32 nr_irqs, i;
 523
 524         mct_int_type = int_type;
 525
 526         /* This driver uses only one global timer interrupt */
 527         mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
 528
 529         /*
 530          * Find out the number of local irqs specified. The local
 531          * timer irqs are specified after the four global timer
 532          * irqs are specified.
 533          */
 534 #ifdef CONFIG_OF
 535         nr_irqs = of_irq_count(np);
 536 #else
 537         nr_irqs = 0;
 538 #endif
 539         for (i = MCT_L0_IRQ; i < nr_irqs; i++)
 540                 mct_irqs[i] = irq_of_parse_and_map(np, i);
 541
 542         exynos4_timer_resources(np, of_iomap(np, 0));
 543         exynos4_clocksource_init();
 544         exynos4_clockevent_init();
 545 }
 546
 547
 548 static void __init mct_init_spi(struct device_node *np)
 549 {
 550         return mct_init_dt(np, MCT_INT_SPI);
 551 }
 552
 553 static void __init mct_init_ppi(struct device_node *np)
 554 {
 555         return mct_init_dt(np, MCT_INT_PPI);
 556 }
 557 CLOCKSOURCE_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
 558 CLOCKSOURCE_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);