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 void dmtimer_systimer_enable(struct dmtimer_systimer *t)
73 {
74 	u32 val;
75 
76 	if (dmtimer_systimer_revision1(t))
77 		val = DMTIMER_TYPE1_ENABLE;
78 	else
79 		val = DMTIMER_TYPE2_ENABLE;
80 
81 	writel_relaxed(val, t->base + t->sysc);
82 }
83 
84 static void dmtimer_systimer_disable(struct dmtimer_systimer *t)
85 {
86 	if (!dmtimer_systimer_revision1(t))
87 		return;
88 
89 	writel_relaxed(DMTIMER_TYPE1_DISABLE, t->base + t->sysc);
90 }
91 
92 static int __init dmtimer_systimer_type1_reset(struct dmtimer_systimer *t)
93 {
94 	void __iomem *syss = t->base + OMAP_TIMER_V1_SYS_STAT_OFFSET;
95 	int ret;
96 	u32 l;
97 
98 	dmtimer_systimer_enable(t);
99 	writel_relaxed(BIT(1) | BIT(2), t->base + t->ifctrl);
100 	ret = readl_poll_timeout_atomic(syss, l, l & BIT(0), 100,
101 					DMTIMER_RESET_WAIT);
102 
103 	return ret;
104 }
105 
106 /* Note we must use io_base instead of func_base for type2 OCP regs */
107 static int __init dmtimer_systimer_type2_reset(struct dmtimer_systimer *t)
108 {
109 	void __iomem *sysc = t->base + t->sysc;
110 	u32 l;
111 
112 	dmtimer_systimer_enable(t);
113 	l = readl_relaxed(sysc);
114 	l |= BIT(0);
115 	writel_relaxed(l, sysc);
116 
117 	return readl_poll_timeout_atomic(sysc, l, !(l & BIT(0)), 100,
118 					 DMTIMER_RESET_WAIT);
119 }
120 
121 static int __init dmtimer_systimer_reset(struct dmtimer_systimer *t)
122 {
123 	int ret;
124 
125 	if (dmtimer_systimer_revision1(t))
126 		ret = dmtimer_systimer_type1_reset(t);
127 	else
128 		ret = dmtimer_systimer_type2_reset(t);
129 	if (ret < 0) {
130 		pr_err("%s failed with %i\n", __func__, ret);
131 
132 		return ret;
133 	}
134 
135 	return 0;
136 }
137 
138 static const struct of_device_id counter_match_table[] = {
139 	{ .compatible = "ti,omap-counter32k" },
140 	{ /* Sentinel */ },
141 };
142 
143 /*
144  * Check if the SoC als has a usable working 32 KiHz counter. The 32 KiHz
145  * counter is handled by timer-ti-32k, but we need to detect it as it
146  * affects the preferred dmtimer system timer configuration. There is
147  * typically no use for a dmtimer clocksource if the 32 KiHz counter is
148  * present, except on am437x as described below.
149  */
150 static void __init dmtimer_systimer_check_counter32k(void)
151 {
152 	struct device_node *np;
153 
154 	if (counter_32k)
155 		return;
156 
157 	np = of_find_matching_node(NULL, counter_match_table);
158 	if (!np) {
159 		counter_32k = -ENODEV;
160 
161 		return;
162 	}
163 
164 	if (of_device_is_available(np))
165 		counter_32k = 1;
166 	else
167 		counter_32k = -ENODEV;
168 
169 	of_node_put(np);
170 }
171 
172 static const struct of_device_id dmtimer_match_table[] = {
173 	{ .compatible = "ti,omap2420-timer", },
174 	{ .compatible = "ti,omap3430-timer", },
175 	{ .compatible = "ti,omap4430-timer", },
176 	{ .compatible = "ti,omap5430-timer", },
177 	{ .compatible = "ti,am335x-timer", },
178 	{ .compatible = "ti,am335x-timer-1ms", },
179 	{ .compatible = "ti,dm814-timer", },
180 	{ .compatible = "ti,dm816-timer", },
181 	{ /* Sentinel */ },
182 };
183 
184 /*
185  * Checks that system timers are configured to not reset and idle during
186  * the generic timer-ti-dm device driver probe. And that the system timer
187  * source clocks are properly configured. Also, let's not hog any DSP and
188  * PWM capable timers unnecessarily as system timers.
189  */
190 static bool __init dmtimer_is_preferred(struct device_node *np)
191 {
192 	if (!of_device_is_available(np))
193 		return false;
194 
195 	if (!of_property_read_bool(np->parent,
196 				   "ti,no-reset-on-init"))
197 		return false;
198 
199 	if (!of_property_read_bool(np->parent, "ti,no-idle"))
200 		return false;
201 
202 	/* Secure gptimer12 is always clocked with a fixed source */
203 	if (!of_property_read_bool(np, "ti,timer-secure")) {
204 		if (!of_property_read_bool(np, "assigned-clocks"))
205 			return false;
206 
207 		if (!of_property_read_bool(np, "assigned-clock-parents"))
208 			return false;
209 	}
210 
211 	if (of_property_read_bool(np, "ti,timer-dsp"))
212 		return false;
213 
214 	if (of_property_read_bool(np, "ti,timer-pwm"))
215 		return false;
216 
217 	return true;
218 }
219 
220 /*
221  * Finds the first available usable always-on timer, and assigns it to either
222  * clockevent or clocksource depending if the counter_32k is available on the
223  * SoC or not.
224  *
225  * Some omap3 boards with unreliable oscillator must not use the counter_32k
226  * or dmtimer1 with 32 KiHz source. Additionally, the boards with unreliable
227  * oscillator should really set counter_32k as disabled, and delete dmtimer1
228  * ti,always-on property, but let's not count on it. For these quirky cases,
229  * we prefer using the always-on secure dmtimer12 with the internal 32 KiHz
230  * clock as the clocksource, and any available dmtimer as clockevent.
231  *
232  * For am437x, we are using am335x style dmtimer clocksource. It is unclear
233  * if this quirk handling is really needed, but let's change it separately
234  * based on testing as it might cause side effects.
235  */
236 static void __init dmtimer_systimer_assign_alwon(void)
237 {
238 	struct device_node *np;
239 	u32 pa = 0;
240 	bool quirk_unreliable_oscillator = false;
241 
242 	/* Quirk unreliable 32 KiHz oscillator with incomplete dts */
243 	if (of_machine_is_compatible("ti,omap3-beagle") ||
244 	    of_machine_is_compatible("timll,omap3-devkit8000")) {
245 		quirk_unreliable_oscillator = true;
246 		counter_32k = -ENODEV;
247 	}
248 
249 	/* Quirk am437x using am335x style dmtimer clocksource */
250 	if (of_machine_is_compatible("ti,am43"))
251 		counter_32k = -ENODEV;
252 
253 	for_each_matching_node(np, dmtimer_match_table) {
254 		if (!dmtimer_is_preferred(np))
255 			continue;
256 
257 		if (of_property_read_bool(np, "ti,timer-alwon")) {
258 			const __be32 *addr;
259 
260 			addr = of_get_address(np, 0, NULL, NULL);
261 			pa = of_translate_address(np, addr);
262 			if (pa) {
263 				/* Quirky omap3 boards must use dmtimer12 */
264 				if (quirk_unreliable_oscillator &&
265 				    pa == 0x48318000)
266 					continue;
267 
268 				of_node_put(np);
269 				break;
270 			}
271 		}
272 	}
273 
274 	/* Usually no need for dmtimer clocksource if we have counter32 */
275 	if (counter_32k >= 0) {
276 		clockevent = pa;
277 		clocksource = 0;
278 	} else {
279 		clocksource = pa;
280 		clockevent = DMTIMER_INST_DONT_CARE;
281 	}
282 }
283 
284 /* Finds the first usable dmtimer, used for the don't care case */
285 static u32 __init dmtimer_systimer_find_first_available(void)
286 {
287 	struct device_node *np;
288 	const __be32 *addr;
289 	u32 pa = 0;
290 
291 	for_each_matching_node(np, dmtimer_match_table) {
292 		if (!dmtimer_is_preferred(np))
293 			continue;
294 
295 		addr = of_get_address(np, 0, NULL, NULL);
296 		pa = of_translate_address(np, addr);
297 		if (pa) {
298 			if (pa == clocksource || pa == clockevent) {
299 				pa = 0;
300 				continue;
301 			}
302 
303 			of_node_put(np);
304 			break;
305 		}
306 	}
307 
308 	return pa;
309 }
310 
311 /* Selects the best clocksource and clockevent to use */
312 static void __init dmtimer_systimer_select_best(void)
313 {
314 	dmtimer_systimer_check_counter32k();
315 	dmtimer_systimer_assign_alwon();
316 
317 	if (clockevent == DMTIMER_INST_DONT_CARE)
318 		clockevent = dmtimer_systimer_find_first_available();
319 
320 	pr_debug("%s: counter_32k: %i clocksource: %08x clockevent: %08x\n",
321 		 __func__, counter_32k, clocksource, clockevent);
322 }
323 
324 /* Interface clocks are only available on some SoCs variants */
325 static int __init dmtimer_systimer_init_clock(struct dmtimer_systimer *t,
326 					      struct device_node *np,
327 					      const char *name,
328 					      unsigned long *rate)
329 {
330 	struct clk *clock;
331 	unsigned long r;
332 	bool is_ick = false;
333 	int error;
334 
335 	is_ick = !strncmp(name, "ick", 3);
336 
337 	clock = of_clk_get_by_name(np, name);
338 	if ((PTR_ERR(clock) == -EINVAL) && is_ick)
339 		return 0;
340 	else if (IS_ERR(clock))
341 		return PTR_ERR(clock);
342 
343 	error = clk_prepare_enable(clock);
344 	if (error)
345 		return error;
346 
347 	r = clk_get_rate(clock);
348 	if (!r)
349 		return -ENODEV;
350 
351 	if (is_ick)
352 		t->ick = clock;
353 	else
354 		t->fck = clock;
355 
356 	*rate = r;
357 
358 	return 0;
359 }
360 
361 static int __init dmtimer_systimer_setup(struct device_node *np,
362 					 struct dmtimer_systimer *t)
363 {
364 	unsigned long rate;
365 	u8 regbase;
366 	int error;
367 
368 	if (!of_device_is_compatible(np->parent, "ti,sysc"))
369 		return -EINVAL;
370 
371 	t->base = of_iomap(np, 0);
372 	if (!t->base)
373 		return -ENXIO;
374 
375 	/*
376 	 * Enable optional assigned-clock-parents configured at the timer
377 	 * node level. For regular device drivers, this is done automatically
378 	 * by bus related code such as platform_drv_probe().
379 	 */
380 	error = of_clk_set_defaults(np, false);
381 	if (error < 0)
382 		pr_err("%s: clock source init failed: %i\n", __func__, error);
383 
384 	/* For ti-sysc, we have timer clocks at the parent module level */
385 	error = dmtimer_systimer_init_clock(t, np->parent, "fck", &rate);
386 	if (error)
387 		goto err_unmap;
388 
389 	t->rate = rate;
390 
391 	error = dmtimer_systimer_init_clock(t, np->parent, "ick", &rate);
392 	if (error)
393 		goto err_unmap;
394 
395 	if (dmtimer_systimer_revision1(t)) {
396 		t->irq_stat = OMAP_TIMER_V1_STAT_OFFSET;
397 		t->irq_ena = OMAP_TIMER_V1_INT_EN_OFFSET;
398 		t->pend = _OMAP_TIMER_WRITE_PEND_OFFSET;
399 		regbase = 0;
400 	} else {
401 		t->irq_stat = OMAP_TIMER_V2_IRQSTATUS;
402 		t->irq_ena = OMAP_TIMER_V2_IRQENABLE_SET;
403 		regbase = OMAP_TIMER_V2_FUNC_OFFSET;
404 		t->pend = regbase + _OMAP_TIMER_WRITE_PEND_OFFSET;
405 	}
406 
407 	t->sysc = OMAP_TIMER_OCP_CFG_OFFSET;
408 	t->load = regbase + _OMAP_TIMER_LOAD_OFFSET;
409 	t->counter = regbase + _OMAP_TIMER_COUNTER_OFFSET;
410 	t->ctrl = regbase + _OMAP_TIMER_CTRL_OFFSET;
411 	t->wakeup = regbase + _OMAP_TIMER_WAKEUP_EN_OFFSET;
412 	t->ifctrl = regbase + _OMAP_TIMER_IF_CTRL_OFFSET;
413 
414 	dmtimer_systimer_reset(t);
415 	dmtimer_systimer_enable(t);
416 	pr_debug("dmtimer rev %08x sysc %08x\n", readl_relaxed(t->base),
417 		 readl_relaxed(t->base + t->sysc));
418 
419 	return 0;
420 
421 err_unmap:
422 	iounmap(t->base);
423 
424 	return error;
425 }
426 
427 /* Clockevent */
428 static struct dmtimer_clockevent *
429 to_dmtimer_clockevent(struct clock_event_device *clockevent)
430 {
431 	return container_of(clockevent, struct dmtimer_clockevent, dev);
432 }
433 
434 static irqreturn_t dmtimer_clockevent_interrupt(int irq, void *data)
435 {
436 	struct dmtimer_clockevent *clkevt = data;
437 	struct dmtimer_systimer *t = &clkevt->t;
438 
439 	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_stat);
440 	clkevt->dev.event_handler(&clkevt->dev);
441 
442 	return IRQ_HANDLED;
443 }
444 
445 static int dmtimer_set_next_event(unsigned long cycles,
446 				  struct clock_event_device *evt)
447 {
448 	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
449 	struct dmtimer_systimer *t = &clkevt->t;
450 	void __iomem *pend = t->base + t->pend;
451 
452 	writel_relaxed(0xffffffff - cycles, t->base + t->counter);
453 	while (readl_relaxed(pend) & WP_TCRR)
454 		cpu_relax();
455 
456 	writel_relaxed(OMAP_TIMER_CTRL_ST, t->base + t->ctrl);
457 	while (readl_relaxed(pend) & WP_TCLR)
458 		cpu_relax();
459 
460 	return 0;
461 }
462 
463 static int dmtimer_clockevent_shutdown(struct clock_event_device *evt)
464 {
465 	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
466 	struct dmtimer_systimer *t = &clkevt->t;
467 	void __iomem *ctrl = t->base + t->ctrl;
468 	u32 l;
469 
470 	l = readl_relaxed(ctrl);
471 	if (l & OMAP_TIMER_CTRL_ST) {
472 		l &= ~BIT(0);
473 		writel_relaxed(l, ctrl);
474 		/* Flush posted write */
475 		l = readl_relaxed(ctrl);
476 		/*  Wait for functional clock period x 3.5 */
477 		udelay(3500000 / t->rate + 1);
478 	}
479 	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_stat);
480 
481 	return 0;
482 }
483 
484 static int dmtimer_set_periodic(struct clock_event_device *evt)
485 {
486 	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
487 	struct dmtimer_systimer *t = &clkevt->t;
488 	void __iomem *pend = t->base + t->pend;
489 
490 	dmtimer_clockevent_shutdown(evt);
491 
492 	/* Looks like we need to first set the load value separately */
493 	writel_relaxed(clkevt->period, t->base + t->load);
494 	while (readl_relaxed(pend) & WP_TLDR)
495 		cpu_relax();
496 
497 	writel_relaxed(clkevt->period, t->base + t->counter);
498 	while (readl_relaxed(pend) & WP_TCRR)
499 		cpu_relax();
500 
501 	writel_relaxed(OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
502 		       t->base + t->ctrl);
503 	while (readl_relaxed(pend) & WP_TCLR)
504 		cpu_relax();
505 
506 	return 0;
507 }
508 
509 static void omap_clockevent_idle(struct clock_event_device *evt)
510 {
511 	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
512 	struct dmtimer_systimer *t = &clkevt->t;
513 
514 	dmtimer_systimer_disable(t);
515 	clk_disable(t->fck);
516 }
517 
518 static void omap_clockevent_unidle(struct clock_event_device *evt)
519 {
520 	struct dmtimer_clockevent *clkevt = to_dmtimer_clockevent(evt);
521 	struct dmtimer_systimer *t = &clkevt->t;
522 	int error;
523 
524 	error = clk_enable(t->fck);
525 	if (error)
526 		pr_err("could not enable timer fck on resume: %i\n", error);
527 
528 	dmtimer_systimer_enable(t);
529 	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena);
530 	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup);
531 }
532 
533 static int __init dmtimer_clockevent_init(struct device_node *np)
534 {
535 	struct dmtimer_clockevent *clkevt;
536 	struct clock_event_device *dev;
537 	struct dmtimer_systimer *t;
538 	int error;
539 
540 	clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
541 	if (!clkevt)
542 		return -ENOMEM;
543 
544 	t = &clkevt->t;
545 	dev = &clkevt->dev;
546 
547 	/*
548 	 * We mostly use cpuidle_coupled with ARM local timers for runtime,
549 	 * so there's probably no use for CLOCK_EVT_FEAT_DYNIRQ here.
550 	 */
551 	dev->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
552 	dev->rating = 300;
553 	dev->set_next_event = dmtimer_set_next_event;
554 	dev->set_state_shutdown = dmtimer_clockevent_shutdown;
555 	dev->set_state_periodic = dmtimer_set_periodic;
556 	dev->set_state_oneshot = dmtimer_clockevent_shutdown;
557 	dev->tick_resume = dmtimer_clockevent_shutdown;
558 	dev->cpumask = cpu_possible_mask;
559 
560 	dev->irq = irq_of_parse_and_map(np, 0);
561 	if (!dev->irq) {
562 		error = -ENXIO;
563 		goto err_out_free;
564 	}
565 
566 	error = dmtimer_systimer_setup(np, &clkevt->t);
567 	if (error)
568 		goto err_out_free;
569 
570 	clkevt->period = 0xffffffff - DIV_ROUND_CLOSEST(t->rate, HZ);
571 
572 	/*
573 	 * For clock-event timers we never read the timer counter and
574 	 * so we are not impacted by errata i103 and i767. Therefore,
575 	 * we can safely ignore this errata for clock-event timers.
576 	 */
577 	writel_relaxed(OMAP_TIMER_CTRL_POSTED, t->base + t->ifctrl);
578 
579 	error = request_irq(dev->irq, dmtimer_clockevent_interrupt,
580 			    IRQF_TIMER, "clockevent", clkevt);
581 	if (error)
582 		goto err_out_unmap;
583 
584 	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena);
585 	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup);
586 
587 	pr_info("TI gptimer clockevent: %s%lu Hz at %pOF\n",
588 		of_find_property(np, "ti,timer-alwon", NULL) ?
589 		"always-on " : "", t->rate, np->parent);
590 
591 	clockevents_config_and_register(dev, t->rate,
592 					3, /* Timer internal resynch latency */
593 					0xffffffff);
594 
595 	if (of_machine_is_compatible("ti,am33xx") ||
596 	    of_machine_is_compatible("ti,am43")) {
597 		dev->suspend = omap_clockevent_idle;
598 		dev->resume = omap_clockevent_unidle;
599 	}
600 
601 	return 0;
602 
603 err_out_unmap:
604 	iounmap(t->base);
605 
606 err_out_free:
607 	kfree(clkevt);
608 
609 	return error;
610 }
611 
612 /* Clocksource */
613 static struct dmtimer_clocksource *
614 to_dmtimer_clocksource(struct clocksource *cs)
615 {
616 	return container_of(cs, struct dmtimer_clocksource, dev);
617 }
618 
619 static u64 dmtimer_clocksource_read_cycles(struct clocksource *cs)
620 {
621 	struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
622 	struct dmtimer_systimer *t = &clksrc->t;
623 
624 	return (u64)readl_relaxed(t->base + t->counter);
625 }
626 
627 static void __iomem *dmtimer_sched_clock_counter;
628 
629 static u64 notrace dmtimer_read_sched_clock(void)
630 {
631 	return readl_relaxed(dmtimer_sched_clock_counter);
632 }
633 
634 static void dmtimer_clocksource_suspend(struct clocksource *cs)
635 {
636 	struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
637 	struct dmtimer_systimer *t = &clksrc->t;
638 
639 	clksrc->loadval = readl_relaxed(t->base + t->counter);
640 	dmtimer_systimer_disable(t);
641 	clk_disable(t->fck);
642 }
643 
644 static void dmtimer_clocksource_resume(struct clocksource *cs)
645 {
646 	struct dmtimer_clocksource *clksrc = to_dmtimer_clocksource(cs);
647 	struct dmtimer_systimer *t = &clksrc->t;
648 	int error;
649 
650 	error = clk_enable(t->fck);
651 	if (error)
652 		pr_err("could not enable timer fck on resume: %i\n", error);
653 
654 	dmtimer_systimer_enable(t);
655 	writel_relaxed(clksrc->loadval, t->base + t->counter);
656 	writel_relaxed(OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
657 		       t->base + t->ctrl);
658 }
659 
660 static int __init dmtimer_clocksource_init(struct device_node *np)
661 {
662 	struct dmtimer_clocksource *clksrc;
663 	struct dmtimer_systimer *t;
664 	struct clocksource *dev;
665 	int error;
666 
667 	clksrc = kzalloc(sizeof(*clksrc), GFP_KERNEL);
668 	if (!clksrc)
669 		return -ENOMEM;
670 
671 	dev = &clksrc->dev;
672 	t = &clksrc->t;
673 
674 	error = dmtimer_systimer_setup(np, t);
675 	if (error)
676 		goto err_out_free;
677 
678 	dev->name = "dmtimer";
679 	dev->rating = 300;
680 	dev->read = dmtimer_clocksource_read_cycles;
681 	dev->mask = CLOCKSOURCE_MASK(32);
682 	dev->flags = CLOCK_SOURCE_IS_CONTINUOUS;
683 
684 	/* Unlike for clockevent, legacy code sets suspend only for am4 */
685 	if (of_machine_is_compatible("ti,am43")) {
686 		dev->suspend = dmtimer_clocksource_suspend;
687 		dev->resume = dmtimer_clocksource_resume;
688 	}
689 
690 	writel_relaxed(0, t->base + t->counter);
691 	writel_relaxed(OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
692 		       t->base + t->ctrl);
693 
694 	pr_info("TI gptimer clocksource: %s%pOF\n",
695 		of_find_property(np, "ti,timer-alwon", NULL) ?
696 		"always-on " : "", np->parent);
697 
698 	if (!dmtimer_sched_clock_counter) {
699 		dmtimer_sched_clock_counter = t->base + t->counter;
700 		sched_clock_register(dmtimer_read_sched_clock, 32, t->rate);
701 	}
702 
703 	if (clocksource_register_hz(dev, t->rate))
704 		pr_err("Could not register clocksource %pOF\n", np);
705 
706 	return 0;
707 
708 err_out_free:
709 	kfree(clksrc);
710 
711 	return -ENODEV;
712 }
713 
714 /*
715  * To detect between a clocksource and clockevent, we assume the device tree
716  * has no interrupts configured for a clocksource timer.
717  */
718 static int __init dmtimer_systimer_init(struct device_node *np)
719 {
720 	const __be32 *addr;
721 	u32 pa;
722 
723 	/* One time init for the preferred timer configuration */
724 	if (!clocksource && !clockevent)
725 		dmtimer_systimer_select_best();
726 
727 	if (!clocksource && !clockevent) {
728 		pr_err("%s: unable to detect system timers, update dtb?\n",
729 		       __func__);
730 
731 		return -EINVAL;
732 	}
733 
734 	addr = of_get_address(np, 0, NULL, NULL);
735 	pa = of_translate_address(np, addr);
736 	if (!pa)
737 		return -EINVAL;
738 
739 	if (counter_32k <= 0 && clocksource == pa)
740 		return dmtimer_clocksource_init(np);
741 
742 	if (clockevent == pa)
743 		return dmtimer_clockevent_init(np);
744 
745 	return 0;
746 }
747 
748 TIMER_OF_DECLARE(systimer_omap2, "ti,omap2420-timer", dmtimer_systimer_init);
749 TIMER_OF_DECLARE(systimer_omap3, "ti,omap3430-timer", dmtimer_systimer_init);
750 TIMER_OF_DECLARE(systimer_omap4, "ti,omap4430-timer", dmtimer_systimer_init);
751 TIMER_OF_DECLARE(systimer_omap5, "ti,omap5430-timer", dmtimer_systimer_init);
752 TIMER_OF_DECLARE(systimer_am33x, "ti,am335x-timer", dmtimer_systimer_init);
753 TIMER_OF_DECLARE(systimer_am3ms, "ti,am335x-timer-1ms", dmtimer_systimer_init);
754 TIMER_OF_DECLARE(systimer_dm814, "ti,dm814-timer", dmtimer_systimer_init);
755 TIMER_OF_DECLARE(systimer_dm816, "ti,dm816-timer", dmtimer_systimer_init);
756