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/cpu_pm.h>
17 #include <linux/clockchips.h>
18 #include <linux/interrupt.h>
19 #include <linux/of_irq.h>
20 #include <linux/of_address.h>
21 #include <linux/io.h>
22 #include <linux/slab.h>
23 #include <linux/sched_clock.h>
24 
25 #include <asm/arch_timer.h>
26 #include <asm/virt.h>
27 
28 #include <clocksource/arm_arch_timer.h>
29 
30 #define CNTTIDR		0x08
31 #define CNTTIDR_VIRT(n)	(BIT(1) << ((n) * 4))
32 
33 #define CNTVCT_LO	0x08
34 #define CNTVCT_HI	0x0c
35 #define CNTFRQ		0x10
36 #define CNTP_TVAL	0x28
37 #define CNTP_CTL	0x2c
38 #define CNTV_TVAL	0x38
39 #define CNTV_CTL	0x3c
40 
41 #define ARCH_CP15_TIMER	BIT(0)
42 #define ARCH_MEM_TIMER	BIT(1)
43 static unsigned arch_timers_present __initdata;
44 
45 static void __iomem *arch_counter_base;
46 
47 struct arch_timer {
48 	void __iomem *base;
49 	struct clock_event_device evt;
50 };
51 
52 #define to_arch_timer(e) container_of(e, struct arch_timer, evt)
53 
54 static u32 arch_timer_rate;
55 
56 enum ppi_nr {
57 	PHYS_SECURE_PPI,
58 	PHYS_NONSECURE_PPI,
59 	VIRT_PPI,
60 	HYP_PPI,
61 	MAX_TIMER_PPI
62 };
63 
64 static int arch_timer_ppi[MAX_TIMER_PPI];
65 
66 static struct clock_event_device __percpu *arch_timer_evt;
67 
68 static bool arch_timer_use_virtual = true;
69 static bool arch_timer_mem_use_virtual;
70 
71 /*
72  * Architected system timer support.
73  */
74 
75 static __always_inline
76 void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
77 			  struct clock_event_device *clk)
78 {
79 	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
80 		struct arch_timer *timer = to_arch_timer(clk);
81 		switch (reg) {
82 		case ARCH_TIMER_REG_CTRL:
83 			writel_relaxed(val, timer->base + CNTP_CTL);
84 			break;
85 		case ARCH_TIMER_REG_TVAL:
86 			writel_relaxed(val, timer->base + CNTP_TVAL);
87 			break;
88 		}
89 	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
90 		struct arch_timer *timer = to_arch_timer(clk);
91 		switch (reg) {
92 		case ARCH_TIMER_REG_CTRL:
93 			writel_relaxed(val, timer->base + CNTV_CTL);
94 			break;
95 		case ARCH_TIMER_REG_TVAL:
96 			writel_relaxed(val, timer->base + CNTV_TVAL);
97 			break;
98 		}
99 	} else {
100 		arch_timer_reg_write_cp15(access, reg, val);
101 	}
102 }
103 
104 static __always_inline
105 u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
106 			struct clock_event_device *clk)
107 {
108 	u32 val;
109 
110 	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
111 		struct arch_timer *timer = to_arch_timer(clk);
112 		switch (reg) {
113 		case ARCH_TIMER_REG_CTRL:
114 			val = readl_relaxed(timer->base + CNTP_CTL);
115 			break;
116 		case ARCH_TIMER_REG_TVAL:
117 			val = readl_relaxed(timer->base + CNTP_TVAL);
118 			break;
119 		}
120 	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
121 		struct arch_timer *timer = to_arch_timer(clk);
122 		switch (reg) {
123 		case ARCH_TIMER_REG_CTRL:
124 			val = readl_relaxed(timer->base + CNTV_CTL);
125 			break;
126 		case ARCH_TIMER_REG_TVAL:
127 			val = readl_relaxed(timer->base + CNTV_TVAL);
128 			break;
129 		}
130 	} else {
131 		val = arch_timer_reg_read_cp15(access, reg);
132 	}
133 
134 	return val;
135 }
136 
137 static __always_inline irqreturn_t timer_handler(const int access,
138 					struct clock_event_device *evt)
139 {
140 	unsigned long ctrl;
141 
142 	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, evt);
143 	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
144 		ctrl |= ARCH_TIMER_CTRL_IT_MASK;
145 		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, evt);
146 		evt->event_handler(evt);
147 		return IRQ_HANDLED;
148 	}
149 
150 	return IRQ_NONE;
151 }
152 
153 static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id)
154 {
155 	struct clock_event_device *evt = dev_id;
156 
157 	return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);
158 }
159 
160 static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)
161 {
162 	struct clock_event_device *evt = dev_id;
163 
164 	return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
165 }
166 
167 static irqreturn_t arch_timer_handler_phys_mem(int irq, void *dev_id)
168 {
169 	struct clock_event_device *evt = dev_id;
170 
171 	return timer_handler(ARCH_TIMER_MEM_PHYS_ACCESS, evt);
172 }
173 
174 static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
175 {
176 	struct clock_event_device *evt = dev_id;
177 
178 	return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
179 }
180 
181 static __always_inline void timer_set_mode(const int access, int mode,
182 				  struct clock_event_device *clk)
183 {
184 	unsigned long ctrl;
185 	switch (mode) {
186 	case CLOCK_EVT_MODE_UNUSED:
187 	case CLOCK_EVT_MODE_SHUTDOWN:
188 		ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
189 		ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
190 		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
191 		break;
192 	default:
193 		break;
194 	}
195 }
196 
197 static void arch_timer_set_mode_virt(enum clock_event_mode mode,
198 				     struct clock_event_device *clk)
199 {
200 	timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode, clk);
201 }
202 
203 static void arch_timer_set_mode_phys(enum clock_event_mode mode,
204 				     struct clock_event_device *clk)
205 {
206 	timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode, clk);
207 }
208 
209 static void arch_timer_set_mode_virt_mem(enum clock_event_mode mode,
210 					 struct clock_event_device *clk)
211 {
212 	timer_set_mode(ARCH_TIMER_MEM_VIRT_ACCESS, mode, clk);
213 }
214 
215 static void arch_timer_set_mode_phys_mem(enum clock_event_mode mode,
216 					 struct clock_event_device *clk)
217 {
218 	timer_set_mode(ARCH_TIMER_MEM_PHYS_ACCESS, mode, clk);
219 }
220 
221 static __always_inline void set_next_event(const int access, unsigned long evt,
222 					   struct clock_event_device *clk)
223 {
224 	unsigned long ctrl;
225 	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
226 	ctrl |= ARCH_TIMER_CTRL_ENABLE;
227 	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
228 	arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt, clk);
229 	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
230 }
231 
232 static int arch_timer_set_next_event_virt(unsigned long evt,
233 					  struct clock_event_device *clk)
234 {
235 	set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
236 	return 0;
237 }
238 
239 static int arch_timer_set_next_event_phys(unsigned long evt,
240 					  struct clock_event_device *clk)
241 {
242 	set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
243 	return 0;
244 }
245 
246 static int arch_timer_set_next_event_virt_mem(unsigned long evt,
247 					      struct clock_event_device *clk)
248 {
249 	set_next_event(ARCH_TIMER_MEM_VIRT_ACCESS, evt, clk);
250 	return 0;
251 }
252 
253 static int arch_timer_set_next_event_phys_mem(unsigned long evt,
254 					      struct clock_event_device *clk)
255 {
256 	set_next_event(ARCH_TIMER_MEM_PHYS_ACCESS, evt, clk);
257 	return 0;
258 }
259 
260 static void __arch_timer_setup(unsigned type,
261 			       struct clock_event_device *clk)
262 {
263 	clk->features = CLOCK_EVT_FEAT_ONESHOT;
264 
265 	if (type == ARCH_CP15_TIMER) {
266 		clk->features |= CLOCK_EVT_FEAT_C3STOP;
267 		clk->name = "arch_sys_timer";
268 		clk->rating = 450;
269 		clk->cpumask = cpumask_of(smp_processor_id());
270 		if (arch_timer_use_virtual) {
271 			clk->irq = arch_timer_ppi[VIRT_PPI];
272 			clk->set_mode = arch_timer_set_mode_virt;
273 			clk->set_next_event = arch_timer_set_next_event_virt;
274 		} else {
275 			clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
276 			clk->set_mode = arch_timer_set_mode_phys;
277 			clk->set_next_event = arch_timer_set_next_event_phys;
278 		}
279 	} else {
280 		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
281 		clk->name = "arch_mem_timer";
282 		clk->rating = 400;
283 		clk->cpumask = cpu_all_mask;
284 		if (arch_timer_mem_use_virtual) {
285 			clk->set_mode = arch_timer_set_mode_virt_mem;
286 			clk->set_next_event =
287 				arch_timer_set_next_event_virt_mem;
288 		} else {
289 			clk->set_mode = arch_timer_set_mode_phys_mem;
290 			clk->set_next_event =
291 				arch_timer_set_next_event_phys_mem;
292 		}
293 	}
294 
295 	clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, clk);
296 
297 	clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
298 }
299 
300 static void arch_timer_configure_evtstream(void)
301 {
302 	int evt_stream_div, pos;
303 
304 	/* Find the closest power of two to the divisor */
305 	evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ;
306 	pos = fls(evt_stream_div);
307 	if (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))
308 		pos--;
309 	/* enable event stream */
310 	arch_timer_evtstrm_enable(min(pos, 15));
311 }
312 
313 static int arch_timer_setup(struct clock_event_device *clk)
314 {
315 	__arch_timer_setup(ARCH_CP15_TIMER, clk);
316 
317 	if (arch_timer_use_virtual)
318 		enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);
319 	else {
320 		enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0);
321 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
322 			enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
323 	}
324 
325 	arch_counter_set_user_access();
326 	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM))
327 		arch_timer_configure_evtstream();
328 
329 	return 0;
330 }
331 
332 static void
333 arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
334 {
335 	/* Who has more than one independent system counter? */
336 	if (arch_timer_rate)
337 		return;
338 
339 	/* Try to determine the frequency from the device tree or CNTFRQ */
340 	if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
341 		if (cntbase)
342 			arch_timer_rate = readl_relaxed(cntbase + CNTFRQ);
343 		else
344 			arch_timer_rate = arch_timer_get_cntfrq();
345 	}
346 
347 	/* Check the timer frequency. */
348 	if (arch_timer_rate == 0)
349 		pr_warn("Architected timer frequency not available\n");
350 }
351 
352 static void arch_timer_banner(unsigned type)
353 {
354 	pr_info("Architected %s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
355 		     type & ARCH_CP15_TIMER ? "cp15" : "",
356 		     type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  " and " : "",
357 		     type & ARCH_MEM_TIMER ? "mmio" : "",
358 		     (unsigned long)arch_timer_rate / 1000000,
359 		     (unsigned long)(arch_timer_rate / 10000) % 100,
360 		     type & ARCH_CP15_TIMER ?
361 			arch_timer_use_virtual ? "virt" : "phys" :
362 			"",
363 		     type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  "/" : "",
364 		     type & ARCH_MEM_TIMER ?
365 			arch_timer_mem_use_virtual ? "virt" : "phys" :
366 			"");
367 }
368 
369 u32 arch_timer_get_rate(void)
370 {
371 	return arch_timer_rate;
372 }
373 
374 static u64 arch_counter_get_cntvct_mem(void)
375 {
376 	u32 vct_lo, vct_hi, tmp_hi;
377 
378 	do {
379 		vct_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
380 		vct_lo = readl_relaxed(arch_counter_base + CNTVCT_LO);
381 		tmp_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
382 	} while (vct_hi != tmp_hi);
383 
384 	return ((u64) vct_hi << 32) | vct_lo;
385 }
386 
387 /*
388  * Default to cp15 based access because arm64 uses this function for
389  * sched_clock() before DT is probed and the cp15 method is guaranteed
390  * to exist on arm64. arm doesn't use this before DT is probed so even
391  * if we don't have the cp15 accessors we won't have a problem.
392  */
393 u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
394 
395 static cycle_t arch_counter_read(struct clocksource *cs)
396 {
397 	return arch_timer_read_counter();
398 }
399 
400 static cycle_t arch_counter_read_cc(const struct cyclecounter *cc)
401 {
402 	return arch_timer_read_counter();
403 }
404 
405 static struct clocksource clocksource_counter = {
406 	.name	= "arch_sys_counter",
407 	.rating	= 400,
408 	.read	= arch_counter_read,
409 	.mask	= CLOCKSOURCE_MASK(56),
410 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_SUSPEND_NONSTOP,
411 };
412 
413 static struct cyclecounter cyclecounter = {
414 	.read	= arch_counter_read_cc,
415 	.mask	= CLOCKSOURCE_MASK(56),
416 };
417 
418 static struct timecounter timecounter;
419 
420 struct timecounter *arch_timer_get_timecounter(void)
421 {
422 	return &timecounter;
423 }
424 
425 static void __init arch_counter_register(unsigned type)
426 {
427 	u64 start_count;
428 
429 	/* Register the CP15 based counter if we have one */
430 	if (type & ARCH_CP15_TIMER)
431 		arch_timer_read_counter = arch_counter_get_cntvct;
432 	else
433 		arch_timer_read_counter = arch_counter_get_cntvct_mem;
434 
435 	start_count = arch_timer_read_counter();
436 	clocksource_register_hz(&clocksource_counter, arch_timer_rate);
437 	cyclecounter.mult = clocksource_counter.mult;
438 	cyclecounter.shift = clocksource_counter.shift;
439 	timecounter_init(&timecounter, &cyclecounter, start_count);
440 
441 	/* 56 bits minimum, so we assume worst case rollover */
442 	sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
443 }
444 
445 static void arch_timer_stop(struct clock_event_device *clk)
446 {
447 	pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
448 		 clk->irq, smp_processor_id());
449 
450 	if (arch_timer_use_virtual)
451 		disable_percpu_irq(arch_timer_ppi[VIRT_PPI]);
452 	else {
453 		disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]);
454 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
455 			disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
456 	}
457 
458 	clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);
459 }
460 
461 static int arch_timer_cpu_notify(struct notifier_block *self,
462 					   unsigned long action, void *hcpu)
463 {
464 	/*
465 	 * Grab cpu pointer in each case to avoid spurious
466 	 * preemptible warnings
467 	 */
468 	switch (action & ~CPU_TASKS_FROZEN) {
469 	case CPU_STARTING:
470 		arch_timer_setup(this_cpu_ptr(arch_timer_evt));
471 		break;
472 	case CPU_DYING:
473 		arch_timer_stop(this_cpu_ptr(arch_timer_evt));
474 		break;
475 	}
476 
477 	return NOTIFY_OK;
478 }
479 
480 static struct notifier_block arch_timer_cpu_nb = {
481 	.notifier_call = arch_timer_cpu_notify,
482 };
483 
484 #ifdef CONFIG_CPU_PM
485 static unsigned int saved_cntkctl;
486 static int arch_timer_cpu_pm_notify(struct notifier_block *self,
487 				    unsigned long action, void *hcpu)
488 {
489 	if (action == CPU_PM_ENTER)
490 		saved_cntkctl = arch_timer_get_cntkctl();
491 	else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT)
492 		arch_timer_set_cntkctl(saved_cntkctl);
493 	return NOTIFY_OK;
494 }
495 
496 static struct notifier_block arch_timer_cpu_pm_notifier = {
497 	.notifier_call = arch_timer_cpu_pm_notify,
498 };
499 
500 static int __init arch_timer_cpu_pm_init(void)
501 {
502 	return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier);
503 }
504 #else
505 static int __init arch_timer_cpu_pm_init(void)
506 {
507 	return 0;
508 }
509 #endif
510 
511 static int __init arch_timer_register(void)
512 {
513 	int err;
514 	int ppi;
515 
516 	arch_timer_evt = alloc_percpu(struct clock_event_device);
517 	if (!arch_timer_evt) {
518 		err = -ENOMEM;
519 		goto out;
520 	}
521 
522 	if (arch_timer_use_virtual) {
523 		ppi = arch_timer_ppi[VIRT_PPI];
524 		err = request_percpu_irq(ppi, arch_timer_handler_virt,
525 					 "arch_timer", arch_timer_evt);
526 	} else {
527 		ppi = arch_timer_ppi[PHYS_SECURE_PPI];
528 		err = request_percpu_irq(ppi, arch_timer_handler_phys,
529 					 "arch_timer", arch_timer_evt);
530 		if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {
531 			ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
532 			err = request_percpu_irq(ppi, arch_timer_handler_phys,
533 						 "arch_timer", arch_timer_evt);
534 			if (err)
535 				free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
536 						arch_timer_evt);
537 		}
538 	}
539 
540 	if (err) {
541 		pr_err("arch_timer: can't register interrupt %d (%d)\n",
542 		       ppi, err);
543 		goto out_free;
544 	}
545 
546 	err = register_cpu_notifier(&arch_timer_cpu_nb);
547 	if (err)
548 		goto out_free_irq;
549 
550 	err = arch_timer_cpu_pm_init();
551 	if (err)
552 		goto out_unreg_notify;
553 
554 	/* Immediately configure the timer on the boot CPU */
555 	arch_timer_setup(this_cpu_ptr(arch_timer_evt));
556 
557 	return 0;
558 
559 out_unreg_notify:
560 	unregister_cpu_notifier(&arch_timer_cpu_nb);
561 out_free_irq:
562 	if (arch_timer_use_virtual)
563 		free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);
564 	else {
565 		free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
566 				arch_timer_evt);
567 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
568 			free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
569 					arch_timer_evt);
570 	}
571 
572 out_free:
573 	free_percpu(arch_timer_evt);
574 out:
575 	return err;
576 }
577 
578 static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
579 {
580 	int ret;
581 	irq_handler_t func;
582 	struct arch_timer *t;
583 
584 	t = kzalloc(sizeof(*t), GFP_KERNEL);
585 	if (!t)
586 		return -ENOMEM;
587 
588 	t->base = base;
589 	t->evt.irq = irq;
590 	__arch_timer_setup(ARCH_MEM_TIMER, &t->evt);
591 
592 	if (arch_timer_mem_use_virtual)
593 		func = arch_timer_handler_virt_mem;
594 	else
595 		func = arch_timer_handler_phys_mem;
596 
597 	ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &t->evt);
598 	if (ret) {
599 		pr_err("arch_timer: Failed to request mem timer irq\n");
600 		kfree(t);
601 	}
602 
603 	return ret;
604 }
605 
606 static const struct of_device_id arch_timer_of_match[] __initconst = {
607 	{ .compatible   = "arm,armv7-timer",    },
608 	{ .compatible   = "arm,armv8-timer",    },
609 	{},
610 };
611 
612 static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
613 	{ .compatible   = "arm,armv7-timer-mem", },
614 	{},
615 };
616 
617 static void __init arch_timer_common_init(void)
618 {
619 	unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
620 
621 	/* Wait until both nodes are probed if we have two timers */
622 	if ((arch_timers_present & mask) != mask) {
623 		if (of_find_matching_node(NULL, arch_timer_mem_of_match) &&
624 				!(arch_timers_present & ARCH_MEM_TIMER))
625 			return;
626 		if (of_find_matching_node(NULL, arch_timer_of_match) &&
627 				!(arch_timers_present & ARCH_CP15_TIMER))
628 			return;
629 	}
630 
631 	arch_timer_banner(arch_timers_present);
632 	arch_counter_register(arch_timers_present);
633 	arch_timer_arch_init();
634 }
635 
636 static void __init arch_timer_init(struct device_node *np)
637 {
638 	int i;
639 
640 	if (arch_timers_present & ARCH_CP15_TIMER) {
641 		pr_warn("arch_timer: multiple nodes in dt, skipping\n");
642 		return;
643 	}
644 
645 	arch_timers_present |= ARCH_CP15_TIMER;
646 	for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
647 		arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
648 	arch_timer_detect_rate(NULL, np);
649 
650 	/*
651 	 * If HYP mode is available, we know that the physical timer
652 	 * has been configured to be accessible from PL1. Use it, so
653 	 * that a guest can use the virtual timer instead.
654 	 *
655 	 * If no interrupt provided for virtual timer, we'll have to
656 	 * stick to the physical timer. It'd better be accessible...
657 	 */
658 	if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
659 		arch_timer_use_virtual = false;
660 
661 		if (!arch_timer_ppi[PHYS_SECURE_PPI] ||
662 		    !arch_timer_ppi[PHYS_NONSECURE_PPI]) {
663 			pr_warn("arch_timer: No interrupt available, giving up\n");
664 			return;
665 		}
666 	}
667 
668 	arch_timer_register();
669 	arch_timer_common_init();
670 }
671 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init);
672 CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_init);
673 
674 static void __init arch_timer_mem_init(struct device_node *np)
675 {
676 	struct device_node *frame, *best_frame = NULL;
677 	void __iomem *cntctlbase, *base;
678 	unsigned int irq;
679 	u32 cnttidr;
680 
681 	arch_timers_present |= ARCH_MEM_TIMER;
682 	cntctlbase = of_iomap(np, 0);
683 	if (!cntctlbase) {
684 		pr_err("arch_timer: Can't find CNTCTLBase\n");
685 		return;
686 	}
687 
688 	cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
689 	iounmap(cntctlbase);
690 
691 	/*
692 	 * Try to find a virtual capable frame. Otherwise fall back to a
693 	 * physical capable frame.
694 	 */
695 	for_each_available_child_of_node(np, frame) {
696 		int n;
697 
698 		if (of_property_read_u32(frame, "frame-number", &n)) {
699 			pr_err("arch_timer: Missing frame-number\n");
700 			of_node_put(best_frame);
701 			of_node_put(frame);
702 			return;
703 		}
704 
705 		if (cnttidr & CNTTIDR_VIRT(n)) {
706 			of_node_put(best_frame);
707 			best_frame = frame;
708 			arch_timer_mem_use_virtual = true;
709 			break;
710 		}
711 		of_node_put(best_frame);
712 		best_frame = of_node_get(frame);
713 	}
714 
715 	base = arch_counter_base = of_iomap(best_frame, 0);
716 	if (!base) {
717 		pr_err("arch_timer: Can't map frame's registers\n");
718 		of_node_put(best_frame);
719 		return;
720 	}
721 
722 	if (arch_timer_mem_use_virtual)
723 		irq = irq_of_parse_and_map(best_frame, 1);
724 	else
725 		irq = irq_of_parse_and_map(best_frame, 0);
726 	of_node_put(best_frame);
727 	if (!irq) {
728 		pr_err("arch_timer: Frame missing %s irq",
729 		       arch_timer_mem_use_virtual ? "virt" : "phys");
730 		return;
731 	}
732 
733 	arch_timer_detect_rate(base, np);
734 	arch_timer_mem_register(base, irq);
735 	arch_timer_common_init();
736 }
737 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
738 		       arch_timer_mem_init);
739