arch/arm/mach-omap2/timer.c

   1 /*
   2  * linux/arch/arm/mach-omap2/timer.c
   3  *
   4  * OMAP2 GP timer support.
   5  *
   6  * Copyright (C) 2009 Nokia Corporation
   7  *
   8  * Update to use new clocksource/clockevent layers
   9  * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
  10  * Copyright (C) 2007 MontaVista Software, Inc.
  11  *
  12  * Original driver:
  13  * Copyright (C) 2005 Nokia Corporation
  14  * Author: Paul Mundt <paul.mundt@nokia.com>
  15  *         Juha Yrjölä <juha.yrjola@nokia.com>
  16  * OMAP Dual-mode timer framework support by Timo Teras
  17  *
  18  * Some parts based off of TI's 24xx code:
  19  *
  20  * Copyright (C) 2004-2009 Texas Instruments, Inc.
  21  *
  22  * Roughly modelled after the OMAP1 MPU timer code.
  23  * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
  24  *
  25  * This file is subject to the terms and conditions of the GNU General Public
  26  * License. See the file "COPYING" in the main directory of this archive
  27  * for more details.
  28  */
  29 #include <linux/init.h>
  30 #include <linux/time.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/err.h>
  33 #include <linux/clk.h>
  34 #include <linux/delay.h>
  35 #include <linux/irq.h>
  36 #include <linux/clocksource.h>
  37 #include <linux/clockchips.h>
  38 #include <linux/slab.h>
  39 #include <linux/of.h>
  40 #include <linux/of_address.h>
  41 #include <linux/of_irq.h>
  42 #include <linux/platform_device.h>
  43 #include <linux/platform_data/dmtimer-omap.h>
  44 #include <linux/sched_clock.h>
  45
  46 #include <asm/mach/time.h>
  47 #include <asm/smp_twd.h>
  48
  49 #include "omap_hwmod.h"
  50 #include "omap_device.h"
  51 #include <plat/counter-32k.h>
  52 #include <plat/dmtimer.h>
  53 #include "omap-pm.h"
  54
  55 #include "soc.h"
  56 #include "common.h"
  57 #include "powerdomain.h"
  58 #include "omap-secure.h"
  59
  60 #define REALTIME_COUNTER_BASE                           0x48243200
  61 #define INCREMENTER_NUMERATOR_OFFSET                    0x10
  62 #define INCREMENTER_DENUMERATOR_RELOAD_OFFSET           0x14
  63 #define NUMERATOR_DENUMERATOR_MASK                      0xfffff000
  64
  65 /* Clockevent code */
  66
  67 static struct omap_dm_timer clkev;
  68 static struct clock_event_device clockevent_gpt;
  69
  70 #ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
  71 static unsigned long arch_timer_freq;
  72
  73 void set_cntfreq(void)
  74 {
  75         omap_smc1(OMAP5_DRA7_MON_SET_CNTFRQ_INDEX, arch_timer_freq);
  76 }
  77 #endif
  78
  79 static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
  80 {
  81         struct clock_event_device *evt = &clockevent_gpt;
  82
  83         __omap_dm_timer_write_status(&clkev, OMAP_TIMER_INT_OVERFLOW);
  84
  85         evt->event_handler(evt);
  86         return IRQ_HANDLED;
  87 }
  88
  89 static struct irqaction omap2_gp_timer_irq = {
  90         .name           = "gp_timer",
  91         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
  92         .handler        = omap2_gp_timer_interrupt,
  93 };
  94
  95 static int omap2_gp_timer_set_next_event(unsigned long cycles,
  96                                          struct clock_event_device *evt)
  97 {
  98         __omap_dm_timer_load_start(&clkev, OMAP_TIMER_CTRL_ST,
  99                                    0xffffffff - cycles, OMAP_TIMER_POSTED);
 100
 101         return 0;
 102 }
 103
 104 static void omap2_gp_timer_set_mode(enum clock_event_mode mode,
 105                                     struct clock_event_device *evt)
 106 {
 107         u32 period;
 108
 109         __omap_dm_timer_stop(&clkev, OMAP_TIMER_POSTED, clkev.rate);
 110
 111         switch (mode) {
 112         case CLOCK_EVT_MODE_PERIODIC:
 113                 period = clkev.rate / HZ;
 114                 period -= 1;
 115                 /* Looks like we need to first set the load value separately */
 116                 __omap_dm_timer_write(&clkev, OMAP_TIMER_LOAD_REG,
 117                                       0xffffffff - period, OMAP_TIMER_POSTED);
 118                 __omap_dm_timer_load_start(&clkev,
 119                                         OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
 120                                         0xffffffff - period, OMAP_TIMER_POSTED);
 121                 break;
 122         case CLOCK_EVT_MODE_ONESHOT:
 123                 break;
 124         case CLOCK_EVT_MODE_UNUSED:
 125         case CLOCK_EVT_MODE_SHUTDOWN:
 126         case CLOCK_EVT_MODE_RESUME:
 127                 break;
 128         }
 129 }
 130
 131 static struct clock_event_device clockevent_gpt = {
 132         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 133         .rating         = 300,
 134         .set_next_event = omap2_gp_timer_set_next_event,
 135         .set_mode       = omap2_gp_timer_set_mode,
 136 };
 137
 138 static struct property device_disabled = {
 139         .name = "status",
 140         .length = sizeof("disabled"),
 141         .value = "disabled",
 142 };
 143
 144 static struct of_device_id omap_timer_match[] __initdata = {
 145         { .compatible = "ti,omap2420-timer", },
 146         { .compatible = "ti,omap3430-timer", },
 147         { .compatible = "ti,omap4430-timer", },
 148         { .compatible = "ti,omap5430-timer", },
 149         { .compatible = "ti,am335x-timer", },
 150         { .compatible = "ti,am335x-timer-1ms", },
 151         { }
 152 };
 153
 154 /**
 155  * omap_get_timer_dt - get a timer using device-tree
 156  * @match       - device-tree match structure for matching a device type
 157  * @property    - optional timer property to match
 158  *
 159  * Helper function to get a timer during early boot using device-tree for use
 160  * as kernel system timer. Optionally, the property argument can be used to
 161  * select a timer with a specific property. Once a timer is found then mark
 162  * the timer node in device-tree as disabled, to prevent the kernel from
 163  * registering this timer as a platform device and so no one else can use it.
 164  */
 165 static struct device_node * __init omap_get_timer_dt(struct of_device_id *match,
 166                                                      const char *property)
 167 {
 168         struct device_node *np;
 169
 170         for_each_matching_node(np, match) {
 171                 if (!of_device_is_available(np))
 172                         continue;
 173
 174                 if (property && !of_get_property(np, property, NULL))
 175                         continue;
 176
 177                 if (!property && (of_get_property(np, "ti,timer-alwon", NULL) ||
 178                                   of_get_property(np, "ti,timer-dsp", NULL) ||
 179                                   of_get_property(np, "ti,timer-pwm", NULL) ||
 180                                   of_get_property(np, "ti,timer-secure", NULL)))
 181                         continue;
 182
 183                 of_add_property(np, &device_disabled);
 184                 return np;
 185         }
 186
 187         return NULL;
 188 }
 189
 190 /**
 191  * omap_dmtimer_init - initialisation function when device tree is used
 192  *
 193  * For secure OMAP3 devices, timers with device type "timer-secure" cannot
 194  * be used by the kernel as they are reserved. Therefore, to prevent the
 195  * kernel registering these devices remove them dynamically from the device
 196  * tree on boot.
 197  */
 198 static void __init omap_dmtimer_init(void)
 199 {
 200         struct device_node *np;
 201
 202         if (!cpu_is_omap34xx())
 203                 return;
 204
 205         /* If we are a secure device, remove any secure timer nodes */
 206         if ((omap_type() != OMAP2_DEVICE_TYPE_GP)) {
 207                 np = omap_get_timer_dt(omap_timer_match, "ti,timer-secure");
 208                 if (np)
 209                         of_node_put(np);
 210         }
 211 }
 212
 213 /**
 214  * omap_dm_timer_get_errata - get errata flags for a timer
 215  *
 216  * Get the timer errata flags that are specific to the OMAP device being used.
 217  */
 218 static u32 __init omap_dm_timer_get_errata(void)
 219 {
 220         if (cpu_is_omap24xx())
 221                 return 0;
 222
 223         return OMAP_TIMER_ERRATA_I103_I767;
 224 }
 225
 226 static int __init omap_dm_timer_init_one(struct omap_dm_timer *timer,
 227                                          const char *fck_source,
 228                                          const char *property,
 229                                          const char **timer_name,
 230                                          int posted)
 231 {
 232         char name[10]; /* 10 = sizeof("gptXX_Xck0") */
 233         const char *oh_name = NULL;
 234         struct device_node *np;
 235         struct omap_hwmod *oh;
 236         struct resource irq, mem;
 237         struct clk *src;
 238         int r = 0;
 239
 240         if (of_have_populated_dt()) {
 241                 np = omap_get_timer_dt(omap_timer_match, property);
 242                 if (!np)
 243                         return -ENODEV;
 244
 245                 of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
 246                 if (!oh_name)
 247                         return -ENODEV;
 248
 249                 timer->irq = irq_of_parse_and_map(np, 0);
 250                 if (!timer->irq)
 251                         return -ENXIO;
 252
 253                 timer->io_base = of_iomap(np, 0);
 254
 255                 of_node_put(np);
 256         } else {
 257                 if (omap_dm_timer_reserve_systimer(timer->id))
 258                         return -ENODEV;
 259
 260                 sprintf(name, "timer%d", timer->id);
 261                 oh_name = name;
 262         }
 263
 264         oh = omap_hwmod_lookup(oh_name);
 265         if (!oh)
 266                 return -ENODEV;
 267
 268         *timer_name = oh->name;
 269
 270         if (!of_have_populated_dt()) {
 271                 r = omap_hwmod_get_resource_byname(oh, IORESOURCE_IRQ, NULL,
 272                                                    &irq);
 273                 if (r)
 274                         return -ENXIO;
 275                 timer->irq = irq.start;
 276
 277                 r = omap_hwmod_get_resource_byname(oh, IORESOURCE_MEM, NULL,
 278                                                    &mem);
 279                 if (r)
 280                         return -ENXIO;
 281
 282                 /* Static mapping, never released */
 283                 timer->io_base = ioremap(mem.start, mem.end - mem.start);
 284         }
 285
 286         if (!timer->io_base)
 287                 return -ENXIO;
 288
 289         /* After the dmtimer is using hwmod these clocks won't be needed */
 290         timer->fclk = clk_get(NULL, omap_hwmod_get_main_clk(oh));
 291         if (IS_ERR(timer->fclk))
 292                 return PTR_ERR(timer->fclk);
 293
 294         src = clk_get(NULL, fck_source);
 295         if (IS_ERR(src))
 296                 return PTR_ERR(src);
 297
 298         if (clk_get_parent(timer->fclk) != src) {
 299                 r = clk_set_parent(timer->fclk, src);
 300                 if (r < 0) {
 301                         pr_warn("%s: %s cannot set source\n", __func__,
 302                                 oh->name);
 303                         clk_put(src);
 304                         return r;
 305                 }
 306         }
 307
 308         clk_put(src);
 309
 310         omap_hwmod_setup_one(oh_name);
 311         omap_hwmod_enable(oh);
 312         __omap_dm_timer_init_regs(timer);
 313
 314         if (posted)
 315                 __omap_dm_timer_enable_posted(timer);
 316
 317         /* Check that the intended posted configuration matches the actual */
 318         if (posted != timer->posted)
 319                 return -EINVAL;
 320
 321         timer->rate = clk_get_rate(timer->fclk);
 322         timer->reserved = 1;
 323
 324         return r;
 325 }
 326
 327 static void __init omap2_gp_clockevent_init(int gptimer_id,
 328                                                 const char *fck_source,
 329                                                 const char *property)
 330 {
 331         int res;
 332
 333         clkev.id = gptimer_id;
 334         clkev.errata = omap_dm_timer_get_errata();
 335
 336         /*
 337          * For clock-event timers we never read the timer counter and
 338          * so we are not impacted by errata i103 and i767. Therefore,
 339          * we can safely ignore this errata for clock-event timers.
 340          */
 341         __omap_dm_timer_override_errata(&clkev, OMAP_TIMER_ERRATA_I103_I767);
 342
 343         res = omap_dm_timer_init_one(&clkev, fck_source, property,
 344                                      &clockevent_gpt.name, OMAP_TIMER_POSTED);
 345         BUG_ON(res);
 346
 347         omap2_gp_timer_irq.dev_id = &clkev;
 348         setup_irq(clkev.irq, &omap2_gp_timer_irq);
 349
 350         __omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
 351
 352         clockevent_gpt.cpumask = cpu_possible_mask;
 353         clockevent_gpt.irq = omap_dm_timer_get_irq(&clkev);
 354         clockevents_config_and_register(&clockevent_gpt, clkev.rate,
 355                                         3, /* Timer internal resynch latency */
 356                                         0xffffffff);
 357
 358         pr_info("OMAP clockevent source: %s at %lu Hz\n", clockevent_gpt.name,
 359                 clkev.rate);
 360 }
 361
 362 /* Clocksource code */
 363 static struct omap_dm_timer clksrc;
 364 static bool use_gptimer_clksrc;
 365
 366 /*
 367  * clocksource
 368  */
 369 static cycle_t clocksource_read_cycles(struct clocksource *cs)
 370 {
 371         return (cycle_t)__omap_dm_timer_read_counter(&clksrc,
 372                                                      OMAP_TIMER_NONPOSTED);
 373 }
 374
 375 static struct clocksource clocksource_gpt = {
 376         .rating         = 300,
 377         .read           = clocksource_read_cycles,
 378         .mask           = CLOCKSOURCE_MASK(32),
 379         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 380 };
 381
 382 static u32 notrace dmtimer_read_sched_clock(void)
 383 {
 384         if (clksrc.reserved)
 385                 return __omap_dm_timer_read_counter(&clksrc,
 386                                                     OMAP_TIMER_NONPOSTED);
 387
 388         return 0;
 389 }
 390
 391 static struct of_device_id omap_counter_match[] __initdata = {
 392         { .compatible = "ti,omap-counter32k", },
 393         { }
 394 };
 395
 396 /* Setup free-running counter for clocksource */
 397 static int __init __maybe_unused omap2_sync32k_clocksource_init(void)
 398 {
 399         int ret;
 400         struct device_node *np = NULL;
 401         struct omap_hwmod *oh;
 402         void __iomem *vbase;
 403         const char *oh_name = "counter_32k";
 404
 405         /*
 406          * If device-tree is present, then search the DT blob
 407          * to see if the 32kHz counter is supported.
 408          */
 409         if (of_have_populated_dt()) {
 410                 np = omap_get_timer_dt(omap_counter_match, NULL);
 411                 if (!np)
 412                         return -ENODEV;
 413
 414                 of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
 415                 if (!oh_name)
 416                         return -ENODEV;
 417         }
 418
 419         /*
 420          * First check hwmod data is available for sync32k counter
 421          */
 422         oh = omap_hwmod_lookup(oh_name);
 423         if (!oh || oh->slaves_cnt == 0)
 424                 return -ENODEV;
 425
 426         omap_hwmod_setup_one(oh_name);
 427
 428         if (np) {
 429                 vbase = of_iomap(np, 0);
 430                 of_node_put(np);
 431         } else {
 432                 vbase = omap_hwmod_get_mpu_rt_va(oh);
 433         }
 434
 435         if (!vbase) {
 436                 pr_warn("%s: failed to get counter_32k resource\n", __func__);
 437                 return -ENXIO;
 438         }
 439
 440         ret = omap_hwmod_enable(oh);
 441         if (ret) {
 442                 pr_warn("%s: failed to enable counter_32k module (%d)\n",
 443                                                         __func__, ret);
 444                 return ret;
 445         }
 446
 447         ret = omap_init_clocksource_32k(vbase);
 448         if (ret) {
 449                 pr_warn("%s: failed to initialize counter_32k as a clocksource (%d)\n",
 450                                                         __func__, ret);
 451                 omap_hwmod_idle(oh);
 452         }
 453
 454         return ret;
 455 }
 456
 457 static void __init omap2_gptimer_clocksource_init(int gptimer_id,
 458                                                   const char *fck_source,
 459                                                   const char *property)
 460 {
 461         int res;
 462
 463         clksrc.id = gptimer_id;
 464         clksrc.errata = omap_dm_timer_get_errata();
 465
 466         res = omap_dm_timer_init_one(&clksrc, fck_source, property,
 467                                      &clocksource_gpt.name,
 468                                      OMAP_TIMER_NONPOSTED);
 469         BUG_ON(res);
 470
 471         __omap_dm_timer_load_start(&clksrc,
 472                                    OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0,
 473                                    OMAP_TIMER_NONPOSTED);
 474         setup_sched_clock(dmtimer_read_sched_clock, 32, clksrc.rate);
 475
 476         if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
 477                 pr_err("Could not register clocksource %s\n",
 478                         clocksource_gpt.name);
 479         else
 480                 pr_info("OMAP clocksource: %s at %lu Hz\n",
 481                         clocksource_gpt.name, clksrc.rate);
 482 }
 483
 484 #ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
 485 /*
 486  * The realtime counter also called master counter, is a free-running
 487  * counter, which is related to real time. It produces the count used
 488  * by the CPU local timer peripherals in the MPU cluster. The timer counts
 489  * at a rate of 6.144 MHz. Because the device operates on different clocks
 490  * in different power modes, the master counter shifts operation between
 491  * clocks, adjusting the increment per clock in hardware accordingly to
 492  * maintain a constant count rate.
 493  */
 494 static void __init realtime_counter_init(void)
 495 {
 496         void __iomem *base;
 497         static struct clk *sys_clk;
 498         unsigned long rate;
 499         unsigned int reg, num, den;
 500
 501         base = ioremap(REALTIME_COUNTER_BASE, SZ_32);
 502         if (!base) {
 503                 pr_err("%s: ioremap failed\n", __func__);
 504                 return;
 505         }
 506         sys_clk = clk_get(NULL, "sys_clkin");
 507         if (IS_ERR(sys_clk)) {
 508                 pr_err("%s: failed to get system clock handle\n", __func__);
 509                 iounmap(base);
 510                 return;
 511         }
 512
 513         rate = clk_get_rate(sys_clk);
 514         /* Numerator/denumerator values refer TRM Realtime Counter section */
 515         switch (rate) {
 516         case 1200000:
 517                 num = 64;
 518                 den = 125;
 519                 break;
 520         case 1300000:
 521                 num = 768;
 522                 den = 1625;
 523                 break;
 524         case 19200000:
 525                 num = 8;
 526                 den = 25;
 527                 break;
 528         case 20000000:
 529                 num = 192;
 530                 den = 625;
 531                 break;
 532         case 2600000:
 533                 num = 384;
 534                 den = 1625;
 535                 break;
 536         case 2700000:
 537                 num = 256;
 538                 den = 1125;
 539                 break;
 540         case 38400000:
 541         default:
 542                 /* Program it for 38.4 MHz */
 543                 num = 4;
 544                 den = 25;
 545                 break;
 546         }
 547
 548         /* Program numerator and denumerator registers */
 549         reg = __raw_readl(base + INCREMENTER_NUMERATOR_OFFSET) &
 550                         NUMERATOR_DENUMERATOR_MASK;
 551         reg |= num;
 552         __raw_writel(reg, base + INCREMENTER_NUMERATOR_OFFSET);
 553
 554         reg = __raw_readl(base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET) &
 555                         NUMERATOR_DENUMERATOR_MASK;
 556         reg |= den;
 557         __raw_writel(reg, base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET);
 558
 559         arch_timer_freq = (rate / den) * num;
 560         set_cntfreq();
 561
 562         iounmap(base);
 563 }
 564 #else
 565 static inline void __init realtime_counter_init(void)
 566 {}
 567 #endif
 568
 569 #define OMAP_SYS_GP_TIMER_INIT(name, clkev_nr, clkev_src, clkev_prop,   \
 570                                clksrc_nr, clksrc_src, clksrc_prop)      \
 571 void __init omap##name##_gptimer_timer_init(void)                       \
 572 {                                                                       \
 573         if (omap_clk_init)                                              \
 574                 omap_clk_init();                                        \
 575         omap_dmtimer_init();                                            \
 576         omap2_gp_clockevent_init((clkev_nr), clkev_src, clkev_prop);    \
 577         omap2_gptimer_clocksource_init((clksrc_nr), clksrc_src,         \
 578                                         clksrc_prop);                   \
 579 }
 580
 581 #define OMAP_SYS_32K_TIMER_INIT(name, clkev_nr, clkev_src, clkev_prop,  \
 582                                 clksrc_nr, clksrc_src, clksrc_prop)     \
 583 void __init omap##name##_sync32k_timer_init(void)               \
 584 {                                                                       \
 585         if (omap_clk_init)                                              \
 586                 omap_clk_init();                                        \
 587         omap_dmtimer_init();                                            \
 588         omap2_gp_clockevent_init((clkev_nr), clkev_src, clkev_prop);    \
 589         /* Enable the use of clocksource="gp_timer" kernel parameter */ \
 590         if (use_gptimer_clksrc)                                         \
 591                 omap2_gptimer_clocksource_init((clksrc_nr), clksrc_src, \
 592                                                 clksrc_prop);           \
 593         else                                                            \
 594                 omap2_sync32k_clocksource_init();                       \
 595 }
 596
 597 #ifdef CONFIG_ARCH_OMAP2
 598 OMAP_SYS_32K_TIMER_INIT(2, 1, "timer_32k_ck", "ti,timer-alwon",
 599                         2, "timer_sys_ck", NULL);
 600 #endif /* CONFIG_ARCH_OMAP2 */
 601
 602 #if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM43XX)
 603 OMAP_SYS_32K_TIMER_INIT(3, 1, "timer_32k_ck", "ti,timer-alwon",
 604                         2, "timer_sys_ck", NULL);
 605 OMAP_SYS_32K_TIMER_INIT(3_secure, 12, "secure_32k_fck", "ti,timer-secure",
 606                         2, "timer_sys_ck", NULL);
 607 #endif /* CONFIG_ARCH_OMAP3 */
 608
 609 #if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX)
 610 OMAP_SYS_GP_TIMER_INIT(3, 2, "timer_sys_ck", NULL,
 611                        1, "timer_sys_ck", "ti,timer-alwon");
 612 #endif
 613
 614 #if defined(CONFIG_ARCH_OMAP4) || defined(CONFIG_SOC_OMAP5) || \
 615         defined(CONFIG_SOC_DRA7XX)
 616 static OMAP_SYS_32K_TIMER_INIT(4, 1, "timer_32k_ck", "ti,timer-alwon",
 617                                2, "sys_clkin_ck", NULL);
 618 #endif
 619
 620 #ifdef CONFIG_ARCH_OMAP4
 621 #ifdef CONFIG_HAVE_ARM_TWD
 622 static DEFINE_TWD_LOCAL_TIMER(twd_local_timer, OMAP44XX_LOCAL_TWD_BASE, 29);
 623 void __init omap4_local_timer_init(void)
 624 {
 625         omap4_sync32k_timer_init();
 626         /* Local timers are not supprted on OMAP4430 ES1.0 */
 627         if (omap_rev() != OMAP4430_REV_ES1_0) {
 628                 int err;
 629
 630                 if (of_have_populated_dt()) {
 631                         clocksource_of_init();
 632                         return;
 633                 }
 634
 635                 err = twd_local_timer_register(&twd_local_timer);
 636                 if (err)
 637                         pr_err("twd_local_timer_register failed %d\n", err);
 638         }
 639 }
 640 #else
 641 void __init omap4_local_timer_init(void)
 642 {
 643         omap4_sync32k_timer_init();
 644 }
 645 #endif /* CONFIG_HAVE_ARM_TWD */
 646 #endif /* CONFIG_ARCH_OMAP4 */
 647
 648 #if defined(CONFIG_SOC_OMAP5) || defined(CONFIG_SOC_DRA7XX)
 649 void __init omap5_realtime_timer_init(void)
 650 {
 651         omap4_sync32k_timer_init();
 652         realtime_counter_init();
 653
 654         clocksource_of_init();
 655 }
 656 #endif /* CONFIG_SOC_OMAP5 || CONFIG_SOC_DRA7XX */
 657
 658 /**
 659  * omap_timer_init - build and register timer device with an
 660  * associated timer hwmod
 661  * @oh: timer hwmod pointer to be used to build timer device
 662  * @user:       parameter that can be passed from calling hwmod API
 663  *
 664  * Called by omap_hwmod_for_each_by_class to register each of the timer
 665  * devices present in the system. The number of timer devices is known
 666  * by parsing through the hwmod database for a given class name. At the
 667  * end of function call memory is allocated for timer device and it is
 668  * registered to the framework ready to be proved by the driver.
 669  */
 670 static int __init omap_timer_init(struct omap_hwmod *oh, void *unused)
 671 {
 672         int id;
 673         int ret = 0;
 674         char *name = "omap_timer";
 675         struct dmtimer_platform_data *pdata;
 676         struct platform_device *pdev;
 677         struct omap_timer_capability_dev_attr *timer_dev_attr;
 678
 679         pr_debug("%s: %s\n", __func__, oh->name);
 680
 681         /* on secure device, do not register secure timer */
 682         timer_dev_attr = oh->dev_attr;
 683         if (omap_type() != OMAP2_DEVICE_TYPE_GP && timer_dev_attr)
 684                 if (timer_dev_attr->timer_capability == OMAP_TIMER_SECURE)
 685                         return ret;
 686
 687         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 688         if (!pdata) {
 689                 pr_err("%s: No memory for [%s]\n", __func__, oh->name);
 690                 return -ENOMEM;
 691         }
 692
 693         /*
 694          * Extract the IDs from name field in hwmod database
 695          * and use the same for constructing ids' for the
 696          * timer devices. In a way, we are avoiding usage of
 697          * static variable witin the function to do the same.
 698          * CAUTION: We have to be careful and make sure the
 699          * name in hwmod database does not change in which case
 700          * we might either make corresponding change here or
 701          * switch back static variable mechanism.
 702          */
 703         sscanf(oh->name, "timer%2d", &id);
 704
 705         if (timer_dev_attr)
 706                 pdata->timer_capability = timer_dev_attr->timer_capability;
 707
 708         pdata->timer_errata = omap_dm_timer_get_errata();
 709         pdata->get_context_loss_count = omap_pm_get_dev_context_loss_count;
 710
 711         pdev = omap_device_build(name, id, oh, pdata, sizeof(*pdata));
 712
 713         if (IS_ERR(pdev)) {
 714                 pr_err("%s: Can't build omap_device for %s: %s.\n",
 715                         __func__, name, oh->name);
 716                 ret = -EINVAL;
 717         }
 718
 719         kfree(pdata);
 720
 721         return ret;
 722 }
 723
 724 /**
 725  * omap2_dm_timer_init - top level regular device initialization
 726  *
 727  * Uses dedicated hwmod api to parse through hwmod database for
 728  * given class name and then build and register the timer device.
 729  */
 730 static int __init omap2_dm_timer_init(void)
 731 {
 732         int ret;
 733
 734         /* If dtb is there, the devices will be created dynamically */
 735         if (of_have_populated_dt())
 736                 return -ENODEV;
 737
 738         ret = omap_hwmod_for_each_by_class("timer", omap_timer_init, NULL);
 739         if (unlikely(ret)) {
 740                 pr_err("%s: device registration failed.\n", __func__);
 741                 return -EINVAL;
 742         }
 743
 744         return 0;
 745 }
 746 omap_arch_initcall(omap2_dm_timer_init);
 747
 748 /**
 749  * omap2_override_clocksource - clocksource override with user configuration
 750  *
 751  * Allows user to override default clocksource, using kernel parameter
 752  *   clocksource="gp_timer"     (For all OMAP2PLUS architectures)
 753  *
 754  * Note that, here we are using same standard kernel parameter "clocksource=",
 755  * and not introducing any OMAP specific interface.
 756  */
 757 static int __init omap2_override_clocksource(char *str)
 758 {
 759         if (!str)
 760                 return 0;
 761         /*
 762          * For OMAP architecture, we only have two options
 763          *    - sync_32k (default)
 764          *    - gp_timer (sys_clk based)
 765          */
 766         if (!strcmp(str, "gp_timer"))
 767                 use_gptimer_clksrc = true;
 768
 769         return 0;
 770 }
 771 early_param("clocksource", omap2_override_clocksource);