drivers/clocksource/timer-ti-dm-systimer.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 #include <linux/clk.h>
   3 #include <linux/clocksource.h>
   4 #include <linux/clockchips.h>
   5 #include <linux/interrupt.h>
   6 #include <linux/io.h>
   7 #include <linux/iopoll.h>
   8 #include <linux/err.h>
   9 #include <linux/of.h>
  10 #include <linux/of_address.h>
  11 #include <linux/of_irq.h>
  12 #include <linux/sched_clock.h>
  13
  14 #include <linux/clk/clk-conf.h>
  15
  16 #include <clocksource/timer-ti-dm.h>
  17 #include <dt-bindings/bus/ti-sysc.h>
  18
  19 /* For type1, set SYSC_OMAP2_CLOCKACTIVITY for fck off on idle, l4 clock on */
  20 #define DMTIMER_TYPE1_ENABLE    ((1 << 9) | (SYSC_IDLE_SMART << 3) | \
  21                                  SYSC_OMAP2_ENAWAKEUP | SYSC_OMAP2_AUTOIDLE)
  22 #define DMTIMER_TYPE1_DISABLE   (SYSC_OMAP2_SOFTRESET | SYSC_OMAP2_AUTOIDLE)
  23 #define DMTIMER_TYPE2_ENABLE    (SYSC_IDLE_SMART_WKUP << 2)
  24 #define DMTIMER_RESET_WAIT      100000
  25
  26 #define DMTIMER_INST_DONT_CARE  ~0U
  27
  28 static int counter_32k;
  29 static u32 clocksource;
  30 static u32 clockevent;
  31
  32 /*
  33  * Subset of the timer registers we use. Note that the register offsets
  34  * depend on the timer revision detected.
  35  */
  36 struct dmtimer_systimer {
  37         void __iomem *base;
  38         u8 sysc;
  39         u8 irq_stat;
  40         u8 irq_ena;
  41         u8 pend;
  42         u8 load;
  43         u8 counter;
  44         u8 ctrl;
  45         u8 wakeup;
  46         u8 ifctrl;
  47         struct clk *fck;
  48         struct clk *ick;
  49         unsigned long rate;
  50 };
  51
  52 struct dmtimer_clockevent {
  53         struct clock_event_device dev;
  54         struct dmtimer_systimer t;
  55         u32 period;
  56 };
  57
  58 struct dmtimer_clocksource {
  59         struct clocksource dev;
  60         struct dmtimer_systimer t;
  61         unsigned int loadval;
  62 };
  63
  64 /* Assumes v1 ip if bits [31:16] are zero */
  65 static bool dmtimer_systimer_revision1(struct dmtimer_systimer *t)
  66 {
  67         u32 tidr = readl_relaxed(t->base);
  68
  69         return !(tidr >> 16);
  70 }
  71
  72 static int __init dmtimer_systimer_type1_reset(struct dmtimer_systimer *t)
  73 {
  74         void __iomem *syss = t->base + OMAP_TIMER_V1_SYS_STAT_OFFSET;
  75         int ret;
  76         u32 l;
  77
  78         writel_relaxed(BIT(1) | BIT(2), t->base + t->ifctrl);
  79         ret = readl_poll_timeout_atomic(syss, l, l & BIT(0), 100,
  80                                         DMTIMER_RESET_WAIT);
  81
  82         return ret;
  83 }
  84
  85 /* Note we must use io_base instead of func_base for type2 OCP regs */
  86 static int __init dmtimer_systimer_type2_reset(struct dmtimer_systimer *t)
  87 {
  88         void __iomem *sysc = t->base + t->sysc;
  89         u32 l;
  90
  91         l = readl_relaxed(sysc);
  92         l |= BIT(0);
  93         writel_relaxed(l, sysc);
  94
  95         return readl_poll_timeout_atomic(sysc, l, !(l & BIT(0)), 100,
  96                                          DMTIMER_RESET_WAIT);
  97 }
  98
  99 static int __init dmtimer_systimer_reset(struct dmtimer_systimer *t)
 100 {
 101         int ret;
 102
 103         if (dmtimer_systimer_revision1(t))
 104                 ret = dmtimer_systimer_type1_reset(t);
 105         else
 106                 ret = dmtimer_systimer_type2_reset(t);
 107         if (ret < 0) {
 108                 pr_err("%s failed with %i\n", __func__, ret);
 109
 110                 return ret;
 111         }
 112
 113         return 0;
 114 }
 115
 116 static const struct of_device_id counter_match_table[] = {
 117         { .compatible = "ti,omap-counter32k" },
 118         { /* Sentinel */ },
 119 };
 120
 121 /*
 122  * Check if the SoC als has a usable working 32 KiHz counter. The 32 KiHz
 123  * counter is handled by timer-ti-32k, but we need to detect it as it
 124  * affects the preferred dmtimer system timer configuration. There is
 125  * typically no use for a dmtimer clocksource if the 32 KiHz counter is
 126  * present, except on am437x as described below.
 127  */
 128 static void __init dmtimer_systimer_check_counter32k(void)
 129 {
 130         struct device_node *np;
 131
 132         if (counter_32k)
 133                 return;
 134
 135         np = of_find_matching_node(NULL, counter_match_table);
 136         if (!np) {
 137                 counter_32k = -ENODEV;
 138
 139                 return;
 140         }
 141
 142         if (of_device_is_available(np))
 143                 counter_32k = 1;
 144         else
 145                 counter_32k = -ENODEV;
 146
 147         of_node_put(np);
 148 }
 149
 150 static const struct of_device_id dmtimer_match_table[] = {
 151         { .compatible = "ti,omap2420-timer", },
 152         { .compatible = "ti,omap3430-timer", },
 153         { .compatible = "ti,omap4430-timer", },
 154         { .compatible = "ti,omap5430-timer", },
 155         { .compatible = "ti,am335x-timer", },
 156         { .compatible = "ti,am335x-timer-1ms", },
 157         { .compatible = "ti,dm814-timer", },
 158         { .compatible = "ti,dm816-timer", },
 159         { /* Sentinel */ },
 160 };
 161
 162 /*
 163  * Checks that system timers are configured to not reset and idle during
 164  * the generic timer-ti-dm device driver probe. And that the system timer
 165  * source clocks are properly configured. Also, let's not hog any DSP and
 166  * PWM capable timers unnecessarily as system timers.
 167  */
 168 static bool __init dmtimer_is_preferred(struct device_node *np)
 169 {
 170         if (!of_device_is_available(np))
 171                 return false;
 172
 173         if (!of_property_read_bool(np->parent,
 174                                    "ti,no-reset-on-init"))
 175                 return false;
 176
 177         if (!of_property_read_bool(np->parent, "ti,no-idle"))
 178                 return false;
 179
 180         /* Secure gptimer12 is always clocked with a fixed source */
 181         if (!of_property_read_bool(np, "ti,timer-secure")) {
 182                 if (!of_property_read_bool(np, "assigned-clocks"))
 183                         return false;
 184
 185                 if (!of_property_read_bool(np, "assigned-clock-parents"))
 186                         return false;
 187         }
 188
 189         if (of_property_read_bool(np, "ti,timer-dsp"))
 190                 return false;
 191
 192         if (of_property_read_bool(np, "ti,timer-pwm"))
 193                 return false;
 194
 195         return true;
 196 }
 197
 198 /*
 199  * Finds the first available usable always-on timer, and assigns it to either
 200  * clockevent or clocksource depending if the counter_32k is available on the
 201  * SoC or not.
 202  *
 203  * Some omap3 boards with unreliable oscillator must not use the counter_32k
 204  * or dmtimer1 with 32 KiHz source. Additionally, the boards with unreliable
 205  * oscillator should really set counter_32k as disabled, and delete dmtimer1
 206  * ti,always-on property, but let's not count on it. For these quirky cases,
 207  * we prefer using the always-on secure dmtimer12 with the internal 32 KiHz
 208  * clock as the clocksource, and any available dmtimer as clockevent.
 209  *
 210  * For am437x, we are using am335x style dmtimer clocksource. It is unclear
 211  * if this quirk handling is really needed, but let's change it separately
 212  * based on testing as it might cause side effects.
 213  */
 214 static void __init dmtimer_systimer_assign_alwon(void)
 215 {
 216         struct device_node *np;
 217         u32 pa = 0;
 218         bool quirk_unreliable_oscillator = false;
 219
 220         /* Quirk unreliable 32 KiHz oscillator with incomplete dts */
 221         if (of_machine_is_compatible("ti,omap3-beagle") ||
 222             of_machine_is_compatible("timll,omap3-devkit8000")) {
 223                 quirk_unreliable_oscillator = true;
 224                 counter_32k = -ENODEV;
 225         }
 226
 227         /* Quirk am437x using am335x style dmtimer clocksource */
 228         if (of_machine_is_compatible("ti,am43"))
 229                 counter_32k = -ENODEV;
 230
 231         for_each_matching_node(np, dmtimer_match_table) {
 232                 if (!dmtimer_is_preferred(np))
 233                         continue;
 234
 235                 if (of_property_read_bool(np, "ti,timer-alwon")) {
 236                         const __be32 *addr;
 237
 238                         addr = of_get_address(np, 0, NULL, NULL);
 239                         pa = of_translate_address(np, addr);
 240                         if (pa) {
 241                                 /* Quirky omap3 boards must use dmtimer12 */
 242                                 if (quirk_unreliable_oscillator &&
 243                                     pa == 0x48318000)
 244                                         continue;
 245
 246                                 of_node_put(np);
 247                                 break;
 248                         }
 249                 }
 250         }
 251
 252         /* Usually no need for dmtimer clocksource if we have counter32 */
 253         if (counter_32k >= 0) {
 254                 clockevent = pa;
 255                 clocksource = 0;
 256         } else {
 257                 clocksource = pa;
 258                 clockevent = DMTIMER_INST_DONT_CARE;
 259         }
 260 }
 261
 262 /* Finds the first usable dmtimer, used for the don't care case */
 263 static u32 __init dmtimer_systimer_find_first_available(void)
 264 {
 265         struct device_node *np;
 266         const __be32 *addr;
 267         u32 pa = 0;
 268
 269         for_each_matching_node(np, dmtimer_match_table) {
 270                 if (!dmtimer_is_preferred(np))
 271                         continue;
 272
 273                 addr = of_get_address(np, 0, NULL, NULL);
 274                 pa = of_translate_address(np, addr);
 275                 if (pa) {
 276                         if (pa == clocksource || pa == clockevent) {
 277                                 pa = 0;
 278                                 continue;
 279                         }
 280
 281                         of_node_put(np);
 282                         break;
 283                 }
 284         }
 285
 286         return pa;
 287 }
 288
 289 /* Selects the best clocksource and clockevent to use */
 290 static void __init dmtimer_systimer_select_best(void)
 291 {
 292         dmtimer_systimer_check_counter32k();
 293         dmtimer_systimer_assign_alwon();
 294
 295         if (clockevent == DMTIMER_INST_DONT_CARE)
 296                 clockevent = dmtimer_systimer_find_first_available();
 297
 298         pr_debug("%s: counter_32k: %i clocksource: %08x clockevent: %08x\n",
 299                  __func__, counter_32k, clocksource, clockevent);
 300 }
 301
 302 /* Interface clocks are only available on some SoCs variants */
 303 static int __init dmtimer_systimer_init_clock(struct dmtimer_systimer *t,
 304                                               struct device_node *np,
 305                                               const char *name,
 306                                               unsigned long *rate)
 307 {
 308         struct clk *clock;
 309         unsigned long r;
 310         bool is_ick = false;
 311         int error;
 312
 313         is_ick = !strncmp(name, "ick", 3);
 314
 315         clock = of_clk_get_by_name(np, name);
 316         if ((PTR_ERR(clock) == -EINVAL) && is_ick)
 317                 return 0;
 318         else if (IS_ERR(clock))
 319                 return PTR_ERR(clock);
 320
 321         error = clk_prepare_enable(clock);
 322         if (error)
 323                 return error;
 324
 325         r = clk_get_rate(clock);
 326         if (!r)
 327                 return -ENODEV;
 328
 329         if (is_ick)
 330                 t->ick = clock;
 331         else
 332                 t->fck = clock;
 333
 334         *rate = r;
 335
 336         return 0;
 337 }
 338
 339 static void dmtimer_systimer_enable(struct dmtimer_systimer *t)
 340 {
 341         u32 val;
 342
 343         if (dmtimer_systimer_revision1(t))
 344                 val = DMTIMER_TYPE1_ENABLE;
 345         else
 346                 val = DMTIMER_TYPE2_ENABLE;
 347
 348         writel_relaxed(val, t->base + t->sysc);
 349 }
 350
 351 static void dmtimer_systimer_disable(struct dmtimer_systimer *t)
 352 {
 353         if (!dmtimer_systimer_revision1(t))
 354                 return;
 355
 356         writel_relaxed(DMTIMER_TYPE1_DISABLE, t->base + t->sysc);
 357 }
 358
 359 static int __init dmtimer_systimer_setup(struct device_node *np,
 360                                          struct dmtimer_systimer *t)
 361 {
 362         unsigned long rate;
 363         u8 regbase;
 364         int error;
 365
 366         if (!of_device_is_compatible(np->parent, "ti,sysc"))
 367                 return -EINVAL;
 368
 369         t->base = of_iomap(np, 0);
 370         if (!t->base)
 371                 return -ENXIO;
 372
 373         /*
 374          * Enable optional assigned-clock-parents configured at the timer
 375          * node level. For regular device drivers, this is done automatically
 376          * by bus related code such as platform_drv_probe().
 377          */
 378         error = of_clk_set_defaults(np, false);
 379         if (error < 0)
 380                 pr_err("%s: clock source init failed: %i\n", __func__, error);
 381
 382         /* For ti-sysc, we have timer clocks at the parent module level */
 383         error = dmtimer_systimer_init_clock(t, np->parent, "fck", &rate);
 384         if (error)
 385                 goto err_unmap;
 386
 387         t->rate = rate;
 388
 389         error = dmtimer_systimer_init_clock(t, np->parent, "ick", &rate);
 390         if (error)
 391                 goto err_unmap;
 392
 393         if (dmtimer_systimer_revision1(t)) {
 394                 t->irq_stat = OMAP_TIMER_V1_STAT_OFFSET;
 395                 t->irq_ena = OMAP_TIMER_V1_INT_EN_OFFSET;
 396                 t->pend = _OMAP_TIMER_WRITE_PEND_OFFSET;
 397                 regbase = 0;
 398         } else {
 399                 t->irq_stat = OMAP_TIMER_V2_IRQSTATUS;
 400                 t->irq_ena = OMAP_TIMER_V2_IRQENABLE_SET;
 401                 regbase = OMAP_TIMER_V2_FUNC_OFFSET;
 402                 t->pend = regbase + _OMAP_TIMER_WRITE_PEND_OFFSET;
 403         }
 404
 405         t->sysc = OMAP_TIMER_OCP_CFG_OFFSET;
 406         t->load = regbase + _OMAP_TIMER_LOAD_OFFSET;
 407         t->counter = regbase + _OMAP_TIMER_COUNTER_OFFSET;
 408         t->ctrl = regbase + _OMAP_TIMER_CTRL_OFFSET;
 409         t->wakeup = regbase + _OMAP_TIMER_WAKEUP_EN_OFFSET;
 410         t->ifctrl = regbase + _OMAP_TIMER_IF_CTRL_OFFSET;
 411
 412         dmtimer_systimer_enable(t);
 413         dmtimer_systimer_reset(t);
 414         pr_debug("dmtimer rev %08x sysc %08x\n", readl_relaxed(t->base),
 415                  readl_relaxed(t->base + t->sysc));
 416
 417         return 0;
 418
 419 err_unmap:
 420         iounmap(t->base);
 421
 422         return error;
 423 }
 424
 425 /* Clockevent */
 426 static struct dmtimer_clockevent *
 427 to_dmtimer_clockevent(struct clock_event_device *clockevent)
 428 {
 429         return container_of(clockevent, struct dmtimer_clockevent, dev);
 430 }
 431
 432 static irqreturn_t dmtimer_clockevent_interrupt(int irq, void *data)
 433 {
 434         struct dmtimer_clockevent *clkevt = data;
 435         struct dmtimer_systimer *t = &clkevt->t;
 436
 437         writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_stat);
 438         clkevt->dev.event_handler(&clkevt->dev);
 439
 440         return IRQ_HANDLED;
 441 }
 442
 443 static int dmtimer_set_next_event(unsigned long cycles,
 444                                   struct clock_event_device *evt)
 445 {
 446         struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
 447         struct dmtimer_systimer *t = &clkevt->t;
 448         void __iomem *pend = t->base + t->pend;
 449
 450         writel_relaxed(0xffffffff - cycles, t->base + t->counter);
 451         while (readl_relaxed(pend) & WP_TCRR)
 452                 cpu_relax();
 453
 454         writel_relaxed(OMAP_TIMER_CTRL_ST, t->base + t->ctrl);
 455         while (readl_relaxed(pend) & WP_TCLR)
 456                 cpu_relax();
 457
 458         return 0;
 459 }
 460
 461 static int dmtimer_clockevent_shutdown(struct clock_event_device *evt)
 462 {
 463         struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
 464         struct dmtimer_systimer *t = &clkevt->t;
 465         void __iomem *ctrl = t->base + t->ctrl;
 466         u32 l;
 467
 468         l = readl_relaxed(ctrl);
 469         if (l & OMAP_TIMER_CTRL_ST) {
 470                 l &= ~BIT(0);
 471                 writel_relaxed(l, ctrl);
 472                 /* Flush posted write */
 473                 l = readl_relaxed(ctrl);
 474                 /*  Wait for functional clock period x 3.5 */
 475                 udelay(3500000 / t->rate + 1);
 476         }
 477         writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_stat);
 478
 479         return 0;
 480 }
 481
 482 static int dmtimer_set_periodic(struct clock_event_device *evt)
 483 {
 484         struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
 485         struct dmtimer_systimer *t = &clkevt->t;
 486         void __iomem *pend = t->base + t->pend;
 487
 488         dmtimer_clockevent_shutdown(evt);
 489
 490         /* Looks like we need to first set the load value separately */
 491         writel_relaxed(clkevt->period, t->base + t->load);
 492         while (readl_relaxed(pend) & WP_TLDR)
 493                 cpu_relax();
 494
 495         writel_relaxed(clkevt->period, t->base + t->counter);
 496         while (readl_relaxed(pend) & WP_TCRR)
 497                 cpu_relax();
 498
 499         writel_relaxed(OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
 500                        t->base + t->ctrl);
 501         while (readl_relaxed(pend) & WP_TCLR)
 502                 cpu_relax();
 503
 504         return 0;
 505 }
 506
 507 static void omap_clockevent_idle(struct clock_event_device *evt)
 508 {
 509         struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
 510         struct dmtimer_systimer *t = &clkevt->t;
 511
 512         dmtimer_systimer_disable(t);
 513         clk_disable(t->fck);
 514 }
 515
 516 static void omap_clockevent_unidle(struct clock_event_device *evt)
 517 {
 518         struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
 519         struct dmtimer_systimer *t = &clkevt->t;
 520         int error;
 521
 522         error = clk_enable(t->fck);
 523         if (error)
 524                 pr_err("could not enable timer fck on resume: %i\n", error);
 525
 526         dmtimer_systimer_enable(t);
 527         writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena);
 528         writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup);
 529 }
 530
 531 static int __init dmtimer_clockevent_init(struct device_node *np)
 532 {
 533         struct dmtimer_clockevent *clkevt;
 534         struct clock_event_device *dev;
 535         struct dmtimer_systimer *t;
 536         int error;
 537
 538         clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
 539         if (!clkevt)
 540                 return -ENOMEM;
 541
 542         t = &clkevt->t;
 543         dev = &clkevt->dev;
 544
 545         /*
 546          * We mostly use cpuidle_coupled with ARM local timers for runtime,
 547          * so there's probably no use for CLOCK_EVT_FEAT_DYNIRQ here.
 548          */
 549         dev->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 550         dev->rating = 300;
 551         dev->set_next_event = dmtimer_set_next_event;
 552         dev->set_state_shutdown = dmtimer_clockevent_shutdown;
 553         dev->set_state_periodic = dmtimer_set_periodic;
 554         dev->set_state_oneshot = dmtimer_clockevent_shutdown;
 555         dev->tick_resume = dmtimer_clockevent_shutdown;
 556         dev->cpumask = cpu_possible_mask;
 557
 558         dev->irq = irq_of_parse_and_map(np, 0);
 559         if (!dev->irq) {
 560                 error = -ENXIO;
 561                 goto err_out_free;
 562         }
 563
 564         error = dmtimer_systimer_setup(np, &clkevt->t);
 565         if (error)
 566                 goto err_out_free;
 567
 568         clkevt->period = 0xffffffff - DIV_ROUND_CLOSEST(t->rate, HZ);
 569
 570         /*
 571          * For clock-event timers we never read the timer counter and
 572          * so we are not impacted by errata i103 and i767. Therefore,
 573          * we can safely ignore this errata for clock-event timers.
 574          */
 575         writel_relaxed(OMAP_TIMER_CTRL_POSTED, t->base + t->ifctrl);
 576
 577         error = request_irq(dev->irq, dmtimer_clockevent_interrupt,
 578                             IRQF_TIMER, "clockevent", clkevt);
 579         if (error)
 580                 goto err_out_unmap;
 581
 582         writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena);
 583         writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup);
 584
 585         pr_info("TI gptimer clockevent: %s%lu Hz at %pOF\n",
 586                 of_find_property(np, "ti,timer-alwon", NULL) ?
 587                 "always-on " : "", t->rate, np->parent);
 588
 589         clockevents_config_and_register(dev, t->rate,
 590                                         3, /* Timer internal resynch latency */
 591                                         0xffffffff);
 592
 593         if (of_machine_is_compatible("ti,am33xx") ||
 594             of_machine_is_compatible("ti,am43")) {
 595                 dev->suspend = omap_clockevent_idle;
 596                 dev->resume = omap_clockevent_unidle;
 597         }
 598
 599         return 0;
 600
 601 err_out_unmap:
 602         iounmap(t->base);
 603
 604 err_out_free:
 605         kfree(clkevt);
 606
 607         return error;
 608 }
 609
 610 /* Clocksource */
 611 static struct dmtimer_clocksource *
 612 to_dmtimer_clocksource(struct clocksource *cs)
 613 {
 614         return container_of(cs, struct dmtimer_clocksource, dev);
 615 }
 616
 617 static u64 dmtimer_clocksource_read_cycles(struct clocksource *cs)
 618 {
 619         struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
 620         struct dmtimer_systimer *t = &clksrc->t;
 621
 622         return (u64)readl_relaxed(t->base + t->counter);
 623 }
 624
 625 static void __iomem *dmtimer_sched_clock_counter;
 626
 627 static u64 notrace dmtimer_read_sched_clock(void)
 628 {
 629         return readl_relaxed(dmtimer_sched_clock_counter);
 630 }
 631
 632 static void dmtimer_clocksource_suspend(struct clocksource *cs)
 633 {
 634         struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
 635         struct dmtimer_systimer *t = &clksrc->t;
 636
 637         clksrc->loadval = readl_relaxed(t->base + t->counter);
 638         dmtimer_systimer_disable(t);
 639         clk_disable(t->fck);
 640 }
 641
 642 static void dmtimer_clocksource_resume(struct clocksource *cs)
 643 {
 644         struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
 645         struct dmtimer_systimer *t = &clksrc->t;
 646         int error;
 647
 648         error = clk_enable(t->fck);
 649         if (error)
 650                 pr_err("could not enable timer fck on resume: %i\n", error);
 651
 652         dmtimer_systimer_enable(t);
 653         writel_relaxed(clksrc->loadval, t->base + t->counter);
 654         writel_relaxed(OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
 655                        t->base + t->ctrl);
 656 }
 657
 658 static int __init dmtimer_clocksource_init(struct device_node *np)
 659 {
 660         struct dmtimer_clocksource *clksrc;
 661         struct dmtimer_systimer *t;
 662         struct clocksource *dev;
 663         int error;
 664
 665         clksrc = kzalloc(sizeof(*clksrc), GFP_KERNEL);
 666         if (!clksrc)
 667                 return -ENOMEM;
 668
 669         dev = &clksrc->dev;
 670         t = &clksrc->t;
 671
 672         error = dmtimer_systimer_setup(np, t);
 673         if (error)
 674                 goto err_out_free;
 675
 676         dev->name = "dmtimer";
 677         dev->rating = 300;
 678         dev->read = dmtimer_clocksource_read_cycles;
 679         dev->mask = CLOCKSOURCE_MASK(32);
 680         dev->flags = CLOCK_SOURCE_IS_CONTINUOUS;
 681
 682         /* Unlike for clockevent, legacy code sets suspend only for am4 */
 683         if (of_machine_is_compatible("ti,am43")) {
 684                 dev->suspend = dmtimer_clocksource_suspend;
 685                 dev->resume = dmtimer_clocksource_resume;
 686         }
 687
 688         writel_relaxed(0, t->base + t->counter);
 689         writel_relaxed(OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
 690                        t->base + t->ctrl);
 691
 692         pr_info("TI gptimer clocksource: %s%pOF\n",
 693                 of_find_property(np, "ti,timer-alwon", NULL) ?
 694                 "always-on " : "", np->parent);
 695
 696         if (!dmtimer_sched_clock_counter) {
 697                 dmtimer_sched_clock_counter = t->base + t->counter;
 698                 sched_clock_register(dmtimer_read_sched_clock, 32, t->rate);
 699         }
 700
 701         if (clocksource_register_hz(dev, t->rate))
 702                 pr_err("Could not register clocksource %pOF\n", np);
 703
 704         return 0;
 705
 706 err_out_free:
 707         kfree(clksrc);
 708
 709         return -ENODEV;
 710 }
 711
 712 /*
 713  * To detect between a clocksource and clockevent, we assume the device tree
 714  * has no interrupts configured for a clocksource timer.
 715  */
 716 static int __init dmtimer_systimer_init(struct device_node *np)
 717 {
 718         const __be32 *addr;
 719         u32 pa;
 720
 721         /* One time init for the preferred timer configuration */
 722         if (!clocksource && !clockevent)
 723                 dmtimer_systimer_select_best();
 724
 725         if (!clocksource && !clockevent) {
 726                 pr_err("%s: unable to detect system timers, update dtb?\n",
 727                        __func__);
 728
 729                 return -EINVAL;
 730         }
 731
 732         addr = of_get_address(np, 0, NULL, NULL);
 733         pa = of_translate_address(np, addr);
 734         if (!pa)
 735                 return -EINVAL;
 736
 737         if (counter_32k <= 0 && clocksource == pa)
 738                 return dmtimer_clocksource_init(np);
 739
 740         if (clockevent == pa)
 741                 return dmtimer_clockevent_init(np);
 742
 743         return 0;
 744 }
 745
 746 TIMER_OF_DECLARE(systimer_omap2, "ti,omap2420-timer", dmtimer_systimer_init);
 747 TIMER_OF_DECLARE(systimer_omap3, "ti,omap3430-timer", dmtimer_systimer_init);
 748 TIMER_OF_DECLARE(systimer_omap4, "ti,omap4430-timer", dmtimer_systimer_init);
 749 TIMER_OF_DECLARE(systimer_omap5, "ti,omap5430-timer", dmtimer_systimer_init);
 750 TIMER_OF_DECLARE(systimer_am33x, "ti,am335x-timer", dmtimer_systimer_init);
 751 TIMER_OF_DECLARE(systimer_am3ms, "ti,am335x-timer-1ms", dmtimer_systimer_init);
 752 TIMER_OF_DECLARE(systimer_dm814, "ti,dm814-timer", dmtimer_systimer_init);
 753 TIMER_OF_DECLARE(systimer_dm816, "ti,dm816-timer", dmtimer_systimer_init);