drivers/clocksource/arm_arch_timer.c

   1 /*
   2  *  linux/drivers/clocksource/arm_arch_timer.c
   3  *
   4  *  Copyright (C) 2011 ARM Ltd.
   5  *  All Rights Reserved
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/init.h>
  12 #include <linux/kernel.h>
  13 #include <linux/device.h>
  14 #include <linux/smp.h>
  15 #include <linux/cpu.h>
  16 #include <linux/clockchips.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/of_irq.h>
  19 #include <linux/of_address.h>
  20 #include <linux/io.h>
  21 #include <linux/slab.h>
  22
  23 #include <asm/arch_timer.h>
  24 #include <asm/virt.h>
  25
  26 #include <clocksource/arm_arch_timer.h>
  27
  28 #define CNTTIDR         0x08
  29 #define CNTTIDR_VIRT(n) (BIT(1) << ((n) * 4))
  30
  31 #define CNTVCT_LO       0x08
  32 #define CNTVCT_HI       0x0c
  33 #define CNTFRQ          0x10
  34 #define CNTP_TVAL       0x28
  35 #define CNTP_CTL        0x2c
  36 #define CNTV_TVAL       0x38
  37 #define CNTV_CTL        0x3c
  38
  39 #define ARCH_CP15_TIMER BIT(0)
  40 #define ARCH_MEM_TIMER  BIT(1)
  41 static unsigned arch_timers_present __initdata;
  42
  43 static void __iomem *arch_counter_base;
  44
  45 struct arch_timer {
  46         void __iomem *base;
  47         struct clock_event_device evt;
  48 };
  49
  50 #define to_arch_timer(e) container_of(e, struct arch_timer, evt)
  51
  52 static u32 arch_timer_rate;
  53
  54 enum ppi_nr {
  55         PHYS_SECURE_PPI,
  56         PHYS_NONSECURE_PPI,
  57         VIRT_PPI,
  58         HYP_PPI,
  59         MAX_TIMER_PPI
  60 };
  61
  62 static int arch_timer_ppi[MAX_TIMER_PPI];
  63
  64 static struct clock_event_device __percpu *arch_timer_evt;
  65
  66 static bool arch_timer_use_virtual = true;
  67 static bool arch_timer_mem_use_virtual;
  68
  69 /*
  70  * Architected system timer support.
  71  */
  72
  73 static __always_inline
  74 void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
  75                           struct clock_event_device *clk)
  76 {
  77         if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
  78                 struct arch_timer *timer = to_arch_timer(clk);
  79                 switch (reg) {
  80                 case ARCH_TIMER_REG_CTRL:
  81                         writel_relaxed(val, timer->base + CNTP_CTL);
  82                         break;
  83                 case ARCH_TIMER_REG_TVAL:
  84                         writel_relaxed(val, timer->base + CNTP_TVAL);
  85                         break;
  86                 }
  87         } else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
  88                 struct arch_timer *timer = to_arch_timer(clk);
  89                 switch (reg) {
  90                 case ARCH_TIMER_REG_CTRL:
  91                         writel_relaxed(val, timer->base + CNTV_CTL);
  92                         break;
  93                 case ARCH_TIMER_REG_TVAL:
  94                         writel_relaxed(val, timer->base + CNTV_TVAL);
  95                         break;
  96                 }
  97         } else {
  98                 arch_timer_reg_write_cp15(access, reg, val);
  99         }
 100 }
 101
 102 static __always_inline
 103 u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
 104                         struct clock_event_device *clk)
 105 {
 106         u32 val;
 107
 108         if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
 109                 struct arch_timer *timer = to_arch_timer(clk);
 110                 switch (reg) {
 111                 case ARCH_TIMER_REG_CTRL:
 112                         val = readl_relaxed(timer->base + CNTP_CTL);
 113                         break;
 114                 case ARCH_TIMER_REG_TVAL:
 115                         val = readl_relaxed(timer->base + CNTP_TVAL);
 116                         break;
 117                 }
 118         } else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
 119                 struct arch_timer *timer = to_arch_timer(clk);
 120                 switch (reg) {
 121                 case ARCH_TIMER_REG_CTRL:
 122                         val = readl_relaxed(timer->base + CNTV_CTL);
 123                         break;
 124                 case ARCH_TIMER_REG_TVAL:
 125                         val = readl_relaxed(timer->base + CNTV_TVAL);
 126                         break;
 127                 }
 128         } else {
 129                 val = arch_timer_reg_read_cp15(access, reg);
 130         }
 131
 132         return val;
 133 }
 134
 135 static __always_inline irqreturn_t timer_handler(const int access,
 136                                         struct clock_event_device *evt)
 137 {
 138         unsigned long ctrl;
 139
 140         ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, evt);
 141         if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
 142                 ctrl |= ARCH_TIMER_CTRL_IT_MASK;
 143                 arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, evt);
 144                 evt->event_handler(evt);
 145                 return IRQ_HANDLED;
 146         }
 147
 148         return IRQ_NONE;
 149 }
 150
 151 static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id)
 152 {
 153         struct clock_event_device *evt = dev_id;
 154
 155         return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);
 156 }
 157
 158 static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)
 159 {
 160         struct clock_event_device *evt = dev_id;
 161
 162         return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
 163 }
 164
 165 static irqreturn_t arch_timer_handler_phys_mem(int irq, void *dev_id)
 166 {
 167         struct clock_event_device *evt = dev_id;
 168
 169         return timer_handler(ARCH_TIMER_MEM_PHYS_ACCESS, evt);
 170 }
 171
 172 static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
 173 {
 174         struct clock_event_device *evt = dev_id;
 175
 176         return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
 177 }
 178
 179 static __always_inline void timer_set_mode(const int access, int mode,
 180                                   struct clock_event_device *clk)
 181 {
 182         unsigned long ctrl;
 183         switch (mode) {
 184         case CLOCK_EVT_MODE_UNUSED:
 185         case CLOCK_EVT_MODE_SHUTDOWN:
 186                 ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
 187                 ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
 188                 arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
 189                 break;
 190         default:
 191                 break;
 192         }
 193 }
 194
 195 static void arch_timer_set_mode_virt(enum clock_event_mode mode,
 196                                      struct clock_event_device *clk)
 197 {
 198         timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode, clk);
 199 }
 200
 201 static void arch_timer_set_mode_phys(enum clock_event_mode mode,
 202                                      struct clock_event_device *clk)
 203 {
 204         timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode, clk);
 205 }
 206
 207 static void arch_timer_set_mode_virt_mem(enum clock_event_mode mode,
 208                                          struct clock_event_device *clk)
 209 {
 210         timer_set_mode(ARCH_TIMER_MEM_VIRT_ACCESS, mode, clk);
 211 }
 212
 213 static void arch_timer_set_mode_phys_mem(enum clock_event_mode mode,
 214                                          struct clock_event_device *clk)
 215 {
 216         timer_set_mode(ARCH_TIMER_MEM_PHYS_ACCESS, mode, clk);
 217 }
 218
 219 static __always_inline void set_next_event(const int access, unsigned long evt,
 220                                            struct clock_event_device *clk)
 221 {
 222         unsigned long ctrl;
 223         ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
 224         ctrl |= ARCH_TIMER_CTRL_ENABLE;
 225         ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
 226         arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt, clk);
 227         arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
 228 }
 229
 230 static int arch_timer_set_next_event_virt(unsigned long evt,
 231                                           struct clock_event_device *clk)
 232 {
 233         set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
 234         return 0;
 235 }
 236
 237 static int arch_timer_set_next_event_phys(unsigned long evt,
 238                                           struct clock_event_device *clk)
 239 {
 240         set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
 241         return 0;
 242 }
 243
 244 static int arch_timer_set_next_event_virt_mem(unsigned long evt,
 245                                               struct clock_event_device *clk)
 246 {
 247         set_next_event(ARCH_TIMER_MEM_VIRT_ACCESS, evt, clk);
 248         return 0;
 249 }
 250
 251 static int arch_timer_set_next_event_phys_mem(unsigned long evt,
 252                                               struct clock_event_device *clk)
 253 {
 254         set_next_event(ARCH_TIMER_MEM_PHYS_ACCESS, evt, clk);
 255         return 0;
 256 }
 257
 258 static void __arch_timer_setup(unsigned type,
 259                                struct clock_event_device *clk)
 260 {
 261         clk->features = CLOCK_EVT_FEAT_ONESHOT;
 262
 263         if (type == ARCH_CP15_TIMER) {
 264                 clk->features |= CLOCK_EVT_FEAT_C3STOP;
 265                 clk->name = "arch_sys_timer";
 266                 clk->rating = 450;
 267                 clk->cpumask = cpumask_of(smp_processor_id());
 268                 if (arch_timer_use_virtual) {
 269                         clk->irq = arch_timer_ppi[VIRT_PPI];
 270                         clk->set_mode = arch_timer_set_mode_virt;
 271                         clk->set_next_event = arch_timer_set_next_event_virt;
 272                 } else {
 273                         clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
 274                         clk->set_mode = arch_timer_set_mode_phys;
 275                         clk->set_next_event = arch_timer_set_next_event_phys;
 276                 }
 277         } else {
 278                 clk->name = "arch_mem_timer";
 279                 clk->rating = 400;
 280                 clk->cpumask = cpu_all_mask;
 281                 if (arch_timer_mem_use_virtual) {
 282                         clk->set_mode = arch_timer_set_mode_virt_mem;
 283                         clk->set_next_event =
 284                                 arch_timer_set_next_event_virt_mem;
 285                 } else {
 286                         clk->set_mode = arch_timer_set_mode_phys_mem;
 287                         clk->set_next_event =
 288                                 arch_timer_set_next_event_phys_mem;
 289                 }
 290         }
 291
 292         clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, clk);
 293
 294         clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
 295 }
 296
 297 static int arch_timer_setup(struct clock_event_device *clk)
 298 {
 299         __arch_timer_setup(ARCH_CP15_TIMER, clk);
 300
 301         if (arch_timer_use_virtual)
 302                 enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);
 303         else {
 304                 enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0);
 305                 if (arch_timer_ppi[PHYS_NONSECURE_PPI])
 306                         enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
 307         }
 308
 309         arch_counter_set_user_access();
 310
 311         return 0;
 312 }
 313
 314 static void
 315 arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
 316 {
 317         /* Who has more than one independent system counter? */
 318         if (arch_timer_rate)
 319                 return;
 320
 321         /* Try to determine the frequency from the device tree or CNTFRQ */
 322         if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
 323                 if (cntbase)
 324                         arch_timer_rate = readl_relaxed(cntbase + CNTFRQ);
 325                 else
 326                         arch_timer_rate = arch_timer_get_cntfrq();
 327         }
 328
 329         /* Check the timer frequency. */
 330         if (arch_timer_rate == 0)
 331                 pr_warn("Architected timer frequency not available\n");
 332 }
 333
 334 static void arch_timer_banner(unsigned type)
 335 {
 336         pr_info("Architected %s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
 337                      type & ARCH_CP15_TIMER ? "cp15" : "",
 338                      type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  " and " : "",
 339                      type & ARCH_MEM_TIMER ? "mmio" : "",
 340                      (unsigned long)arch_timer_rate / 1000000,
 341                      (unsigned long)(arch_timer_rate / 10000) % 100,
 342                      type & ARCH_CP15_TIMER ?
 343                         arch_timer_use_virtual ? "virt" : "phys" :
 344                         "",
 345                      type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  "/" : "",
 346                      type & ARCH_MEM_TIMER ?
 347                         arch_timer_mem_use_virtual ? "virt" : "phys" :
 348                         "");
 349 }
 350
 351 u32 arch_timer_get_rate(void)
 352 {
 353         return arch_timer_rate;
 354 }
 355
 356 static u64 arch_counter_get_cntvct_mem(void)
 357 {
 358         u32 vct_lo, vct_hi, tmp_hi;
 359
 360         do {
 361                 vct_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
 362                 vct_lo = readl_relaxed(arch_counter_base + CNTVCT_LO);
 363                 tmp_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
 364         } while (vct_hi != tmp_hi);
 365
 366         return ((u64) vct_hi << 32) | vct_lo;
 367 }
 368
 369 /*
 370  * Default to cp15 based access because arm64 uses this function for
 371  * sched_clock() before DT is probed and the cp15 method is guaranteed
 372  * to exist on arm64. arm doesn't use this before DT is probed so even
 373  * if we don't have the cp15 accessors we won't have a problem.
 374  */
 375 u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
 376
 377 static cycle_t arch_counter_read(struct clocksource *cs)
 378 {
 379         return arch_timer_read_counter();
 380 }
 381
 382 static cycle_t arch_counter_read_cc(const struct cyclecounter *cc)
 383 {
 384         return arch_timer_read_counter();
 385 }
 386
 387 static struct clocksource clocksource_counter = {
 388         .name   = "arch_sys_counter",
 389         .rating = 400,
 390         .read   = arch_counter_read,
 391         .mask   = CLOCKSOURCE_MASK(56),
 392         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 393 };
 394
 395 static struct cyclecounter cyclecounter = {
 396         .read   = arch_counter_read_cc,
 397         .mask   = CLOCKSOURCE_MASK(56),
 398 };
 399
 400 static struct timecounter timecounter;
 401
 402 struct timecounter *arch_timer_get_timecounter(void)
 403 {
 404         return &timecounter;
 405 }
 406
 407 static void __init arch_counter_register(unsigned type)
 408 {
 409         u64 start_count;
 410
 411         /* Register the CP15 based counter if we have one */
 412         if (type & ARCH_CP15_TIMER)
 413                 arch_timer_read_counter = arch_counter_get_cntvct;
 414         else
 415                 arch_timer_read_counter = arch_counter_get_cntvct_mem;
 416
 417         start_count = arch_timer_read_counter();
 418         clocksource_register_hz(&clocksource_counter, arch_timer_rate);
 419         cyclecounter.mult = clocksource_counter.mult;
 420         cyclecounter.shift = clocksource_counter.shift;
 421         timecounter_init(&timecounter, &cyclecounter, start_count);
 422 }
 423
 424 static void arch_timer_stop(struct clock_event_device *clk)
 425 {
 426         pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
 427                  clk->irq, smp_processor_id());
 428
 429         if (arch_timer_use_virtual)
 430                 disable_percpu_irq(arch_timer_ppi[VIRT_PPI]);
 431         else {
 432                 disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]);
 433                 if (arch_timer_ppi[PHYS_NONSECURE_PPI])
 434                         disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
 435         }
 436
 437         clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);
 438 }
 439
 440 static int arch_timer_cpu_notify(struct notifier_block *self,
 441                                            unsigned long action, void *hcpu)
 442 {
 443         /*
 444          * Grab cpu pointer in each case to avoid spurious
 445          * preemptible warnings
 446          */
 447         switch (action & ~CPU_TASKS_FROZEN) {
 448         case CPU_STARTING:
 449                 arch_timer_setup(this_cpu_ptr(arch_timer_evt));
 450                 break;
 451         case CPU_DYING:
 452                 arch_timer_stop(this_cpu_ptr(arch_timer_evt));
 453                 break;
 454         }
 455
 456         return NOTIFY_OK;
 457 }
 458
 459 static struct notifier_block arch_timer_cpu_nb = {
 460         .notifier_call = arch_timer_cpu_notify,
 461 };
 462
 463 static int __init arch_timer_register(void)
 464 {
 465         int err;
 466         int ppi;
 467
 468         arch_timer_evt = alloc_percpu(struct clock_event_device);
 469         if (!arch_timer_evt) {
 470                 err = -ENOMEM;
 471                 goto out;
 472         }
 473
 474         if (arch_timer_use_virtual) {
 475                 ppi = arch_timer_ppi[VIRT_PPI];
 476                 err = request_percpu_irq(ppi, arch_timer_handler_virt,
 477                                          "arch_timer", arch_timer_evt);
 478         } else {
 479                 ppi = arch_timer_ppi[PHYS_SECURE_PPI];
 480                 err = request_percpu_irq(ppi, arch_timer_handler_phys,
 481                                          "arch_timer", arch_timer_evt);
 482                 if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {
 483                         ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
 484                         err = request_percpu_irq(ppi, arch_timer_handler_phys,
 485                                                  "arch_timer", arch_timer_evt);
 486                         if (err)
 487                                 free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
 488                                                 arch_timer_evt);
 489                 }
 490         }
 491
 492         if (err) {
 493                 pr_err("arch_timer: can't register interrupt %d (%d)\n",
 494                        ppi, err);
 495                 goto out_free;
 496         }
 497
 498         err = register_cpu_notifier(&arch_timer_cpu_nb);
 499         if (err)
 500                 goto out_free_irq;
 501
 502         /* Immediately configure the timer on the boot CPU */
 503         arch_timer_setup(this_cpu_ptr(arch_timer_evt));
 504
 505         return 0;
 506
 507 out_free_irq:
 508         if (arch_timer_use_virtual)
 509                 free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);
 510         else {
 511                 free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
 512                                 arch_timer_evt);
 513                 if (arch_timer_ppi[PHYS_NONSECURE_PPI])
 514                         free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
 515                                         arch_timer_evt);
 516         }
 517
 518 out_free:
 519         free_percpu(arch_timer_evt);
 520 out:
 521         return err;
 522 }
 523
 524 static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
 525 {
 526         int ret;
 527         irq_handler_t func;
 528         struct arch_timer *t;
 529
 530         t = kzalloc(sizeof(*t), GFP_KERNEL);
 531         if (!t)
 532                 return -ENOMEM;
 533
 534         t->base = base;
 535         t->evt.irq = irq;
 536         __arch_timer_setup(ARCH_MEM_TIMER, &t->evt);
 537
 538         if (arch_timer_mem_use_virtual)
 539                 func = arch_timer_handler_virt_mem;
 540         else
 541                 func = arch_timer_handler_phys_mem;
 542
 543         ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &t->evt);
 544         if (ret) {
 545                 pr_err("arch_timer: Failed to request mem timer irq\n");
 546                 kfree(t);
 547         }
 548
 549         return ret;
 550 }
 551
 552 static const struct of_device_id arch_timer_of_match[] __initconst = {
 553         { .compatible   = "arm,armv7-timer",    },
 554         { .compatible   = "arm,armv8-timer",    },
 555         {},
 556 };
 557
 558 static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
 559         { .compatible   = "arm,armv7-timer-mem", },
 560         {},
 561 };
 562
 563 static void __init arch_timer_common_init(void)
 564 {
 565         unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
 566
 567         /* Wait until both nodes are probed if we have two timers */
 568         if ((arch_timers_present & mask) != mask) {
 569                 if (of_find_matching_node(NULL, arch_timer_mem_of_match) &&
 570                                 !(arch_timers_present & ARCH_MEM_TIMER))
 571                         return;
 572                 if (of_find_matching_node(NULL, arch_timer_of_match) &&
 573                                 !(arch_timers_present & ARCH_CP15_TIMER))
 574                         return;
 575         }
 576
 577         arch_timer_banner(arch_timers_present);
 578         arch_counter_register(arch_timers_present);
 579         arch_timer_arch_init();
 580 }
 581
 582 static void __init arch_timer_init(struct device_node *np)
 583 {
 584         int i;
 585
 586         if (arch_timers_present & ARCH_CP15_TIMER) {
 587                 pr_warn("arch_timer: multiple nodes in dt, skipping\n");
 588                 return;
 589         }
 590
 591         arch_timers_present |= ARCH_CP15_TIMER;
 592         for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
 593                 arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
 594         arch_timer_detect_rate(NULL, np);
 595
 596         /*
 597          * If HYP mode is available, we know that the physical timer
 598          * has been configured to be accessible from PL1. Use it, so
 599          * that a guest can use the virtual timer instead.
 600          *
 601          * If no interrupt provided for virtual timer, we'll have to
 602          * stick to the physical timer. It'd better be accessible...
 603          */
 604         if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
 605                 arch_timer_use_virtual = false;
 606
 607                 if (!arch_timer_ppi[PHYS_SECURE_PPI] ||
 608                     !arch_timer_ppi[PHYS_NONSECURE_PPI]) {
 609                         pr_warn("arch_timer: No interrupt available, giving up\n");
 610                         return;
 611                 }
 612         }
 613
 614         arch_timer_register();
 615         arch_timer_common_init();
 616 }
 617 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init);
 618 CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_init);
 619
 620 static void __init arch_timer_mem_init(struct device_node *np)
 621 {
 622         struct device_node *frame, *best_frame = NULL;
 623         void __iomem *cntctlbase, *base;
 624         unsigned int irq;
 625         u32 cnttidr;
 626
 627         arch_timers_present |= ARCH_MEM_TIMER;
 628         cntctlbase = of_iomap(np, 0);
 629         if (!cntctlbase) {
 630                 pr_err("arch_timer: Can't find CNTCTLBase\n");
 631                 return;
 632         }
 633
 634         cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
 635         iounmap(cntctlbase);
 636
 637         /*
 638          * Try to find a virtual capable frame. Otherwise fall back to a
 639          * physical capable frame.
 640          */
 641         for_each_available_child_of_node(np, frame) {
 642                 int n;
 643
 644                 if (of_property_read_u32(frame, "frame-number", &n)) {
 645                         pr_err("arch_timer: Missing frame-number\n");
 646                         of_node_put(best_frame);
 647                         of_node_put(frame);
 648                         return;
 649                 }
 650
 651                 if (cnttidr & CNTTIDR_VIRT(n)) {
 652                         of_node_put(best_frame);
 653                         best_frame = frame;
 654                         arch_timer_mem_use_virtual = true;
 655                         break;
 656                 }
 657                 of_node_put(best_frame);
 658                 best_frame = of_node_get(frame);
 659         }
 660
 661         base = arch_counter_base = of_iomap(best_frame, 0);
 662         if (!base) {
 663                 pr_err("arch_timer: Can't map frame's registers\n");
 664                 of_node_put(best_frame);
 665                 return;
 666         }
 667
 668         if (arch_timer_mem_use_virtual)
 669                 irq = irq_of_parse_and_map(best_frame, 1);
 670         else
 671                 irq = irq_of_parse_and_map(best_frame, 0);
 672         of_node_put(best_frame);
 673         if (!irq) {
 674                 pr_err("arch_timer: Frame missing %s irq",
 675                        arch_timer_mem_use_virtual ? "virt" : "phys");
 676                 return;
 677         }
 678
 679         arch_timer_detect_rate(base, np);
 680         arch_timer_mem_register(base, irq);
 681         arch_timer_common_init();
 682 }
 683 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
 684                        arch_timer_mem_init);