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_c3stop;
70 static bool arch_timer_mem_use_virtual;
71 
72 /*
73  * Architected system timer support.
74  */
75 
76 static __always_inline
77 void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
78 			  struct clock_event_device *clk)
79 {
80 	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
81 		struct arch_timer *timer = to_arch_timer(clk);
82 		switch (reg) {
83 		case ARCH_TIMER_REG_CTRL:
84 			writel_relaxed(val, timer->base + CNTP_CTL);
85 			break;
86 		case ARCH_TIMER_REG_TVAL:
87 			writel_relaxed(val, timer->base + CNTP_TVAL);
88 			break;
89 		}
90 	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
91 		struct arch_timer *timer = to_arch_timer(clk);
92 		switch (reg) {
93 		case ARCH_TIMER_REG_CTRL:
94 			writel_relaxed(val, timer->base + CNTV_CTL);
95 			break;
96 		case ARCH_TIMER_REG_TVAL:
97 			writel_relaxed(val, timer->base + CNTV_TVAL);
98 			break;
99 		}
100 	} else {
101 		arch_timer_reg_write_cp15(access, reg, val);
102 	}
103 }
104 
105 static __always_inline
106 u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
107 			struct clock_event_device *clk)
108 {
109 	u32 val;
110 
111 	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
112 		struct arch_timer *timer = to_arch_timer(clk);
113 		switch (reg) {
114 		case ARCH_TIMER_REG_CTRL:
115 			val = readl_relaxed(timer->base + CNTP_CTL);
116 			break;
117 		case ARCH_TIMER_REG_TVAL:
118 			val = readl_relaxed(timer->base + CNTP_TVAL);
119 			break;
120 		}
121 	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
122 		struct arch_timer *timer = to_arch_timer(clk);
123 		switch (reg) {
124 		case ARCH_TIMER_REG_CTRL:
125 			val = readl_relaxed(timer->base + CNTV_CTL);
126 			break;
127 		case ARCH_TIMER_REG_TVAL:
128 			val = readl_relaxed(timer->base + CNTV_TVAL);
129 			break;
130 		}
131 	} else {
132 		val = arch_timer_reg_read_cp15(access, reg);
133 	}
134 
135 	return val;
136 }
137 
138 static __always_inline irqreturn_t timer_handler(const int access,
139 					struct clock_event_device *evt)
140 {
141 	unsigned long ctrl;
142 
143 	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, evt);
144 	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
145 		ctrl |= ARCH_TIMER_CTRL_IT_MASK;
146 		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, evt);
147 		evt->event_handler(evt);
148 		return IRQ_HANDLED;
149 	}
150 
151 	return IRQ_NONE;
152 }
153 
154 static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id)
155 {
156 	struct clock_event_device *evt = dev_id;
157 
158 	return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);
159 }
160 
161 static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)
162 {
163 	struct clock_event_device *evt = dev_id;
164 
165 	return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
166 }
167 
168 static irqreturn_t arch_timer_handler_phys_mem(int irq, void *dev_id)
169 {
170 	struct clock_event_device *evt = dev_id;
171 
172 	return timer_handler(ARCH_TIMER_MEM_PHYS_ACCESS, evt);
173 }
174 
175 static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
176 {
177 	struct clock_event_device *evt = dev_id;
178 
179 	return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
180 }
181 
182 static __always_inline void timer_set_mode(const int access, int mode,
183 				  struct clock_event_device *clk)
184 {
185 	unsigned long ctrl;
186 	switch (mode) {
187 	case CLOCK_EVT_MODE_UNUSED:
188 	case CLOCK_EVT_MODE_SHUTDOWN:
189 		ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
190 		ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
191 		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
192 		break;
193 	default:
194 		break;
195 	}
196 }
197 
198 static void arch_timer_set_mode_virt(enum clock_event_mode mode,
199 				     struct clock_event_device *clk)
200 {
201 	timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode, clk);
202 }
203 
204 static void arch_timer_set_mode_phys(enum clock_event_mode mode,
205 				     struct clock_event_device *clk)
206 {
207 	timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode, clk);
208 }
209 
210 static void arch_timer_set_mode_virt_mem(enum clock_event_mode mode,
211 					 struct clock_event_device *clk)
212 {
213 	timer_set_mode(ARCH_TIMER_MEM_VIRT_ACCESS, mode, clk);
214 }
215 
216 static void arch_timer_set_mode_phys_mem(enum clock_event_mode mode,
217 					 struct clock_event_device *clk)
218 {
219 	timer_set_mode(ARCH_TIMER_MEM_PHYS_ACCESS, mode, clk);
220 }
221 
222 static __always_inline void set_next_event(const int access, unsigned long evt,
223 					   struct clock_event_device *clk)
224 {
225 	unsigned long ctrl;
226 	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
227 	ctrl |= ARCH_TIMER_CTRL_ENABLE;
228 	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
229 	arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt, clk);
230 	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
231 }
232 
233 static int arch_timer_set_next_event_virt(unsigned long evt,
234 					  struct clock_event_device *clk)
235 {
236 	set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
237 	return 0;
238 }
239 
240 static int arch_timer_set_next_event_phys(unsigned long evt,
241 					  struct clock_event_device *clk)
242 {
243 	set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
244 	return 0;
245 }
246 
247 static int arch_timer_set_next_event_virt_mem(unsigned long evt,
248 					      struct clock_event_device *clk)
249 {
250 	set_next_event(ARCH_TIMER_MEM_VIRT_ACCESS, evt, clk);
251 	return 0;
252 }
253 
254 static int arch_timer_set_next_event_phys_mem(unsigned long evt,
255 					      struct clock_event_device *clk)
256 {
257 	set_next_event(ARCH_TIMER_MEM_PHYS_ACCESS, evt, clk);
258 	return 0;
259 }
260 
261 static void __arch_timer_setup(unsigned type,
262 			       struct clock_event_device *clk)
263 {
264 	clk->features = CLOCK_EVT_FEAT_ONESHOT;
265 
266 	if (type == ARCH_CP15_TIMER) {
267 		if (arch_timer_c3stop)
268 			clk->features |= CLOCK_EVT_FEAT_C3STOP;
269 		clk->name = "arch_sys_timer";
270 		clk->rating = 450;
271 		clk->cpumask = cpumask_of(smp_processor_id());
272 		if (arch_timer_use_virtual) {
273 			clk->irq = arch_timer_ppi[VIRT_PPI];
274 			clk->set_mode = arch_timer_set_mode_virt;
275 			clk->set_next_event = arch_timer_set_next_event_virt;
276 		} else {
277 			clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
278 			clk->set_mode = arch_timer_set_mode_phys;
279 			clk->set_next_event = arch_timer_set_next_event_phys;
280 		}
281 	} else {
282 		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
283 		clk->name = "arch_mem_timer";
284 		clk->rating = 400;
285 		clk->cpumask = cpu_all_mask;
286 		if (arch_timer_mem_use_virtual) {
287 			clk->set_mode = arch_timer_set_mode_virt_mem;
288 			clk->set_next_event =
289 				arch_timer_set_next_event_virt_mem;
290 		} else {
291 			clk->set_mode = arch_timer_set_mode_phys_mem;
292 			clk->set_next_event =
293 				arch_timer_set_next_event_phys_mem;
294 		}
295 	}
296 
297 	clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, clk);
298 
299 	clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
300 }
301 
302 static void arch_timer_configure_evtstream(void)
303 {
304 	int evt_stream_div, pos;
305 
306 	/* Find the closest power of two to the divisor */
307 	evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ;
308 	pos = fls(evt_stream_div);
309 	if (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))
310 		pos--;
311 	/* enable event stream */
312 	arch_timer_evtstrm_enable(min(pos, 15));
313 }
314 
315 static int arch_timer_setup(struct clock_event_device *clk)
316 {
317 	__arch_timer_setup(ARCH_CP15_TIMER, clk);
318 
319 	if (arch_timer_use_virtual)
320 		enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);
321 	else {
322 		enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0);
323 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
324 			enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
325 	}
326 
327 	arch_counter_set_user_access();
328 	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM))
329 		arch_timer_configure_evtstream();
330 
331 	return 0;
332 }
333 
334 static void
335 arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
336 {
337 	/* Who has more than one independent system counter? */
338 	if (arch_timer_rate)
339 		return;
340 
341 	/* Try to determine the frequency from the device tree or CNTFRQ */
342 	if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
343 		if (cntbase)
344 			arch_timer_rate = readl_relaxed(cntbase + CNTFRQ);
345 		else
346 			arch_timer_rate = arch_timer_get_cntfrq();
347 	}
348 
349 	/* Check the timer frequency. */
350 	if (arch_timer_rate == 0)
351 		pr_warn("Architected timer frequency not available\n");
352 }
353 
354 static void arch_timer_banner(unsigned type)
355 {
356 	pr_info("Architected %s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
357 		     type & ARCH_CP15_TIMER ? "cp15" : "",
358 		     type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  " and " : "",
359 		     type & ARCH_MEM_TIMER ? "mmio" : "",
360 		     (unsigned long)arch_timer_rate / 1000000,
361 		     (unsigned long)(arch_timer_rate / 10000) % 100,
362 		     type & ARCH_CP15_TIMER ?
363 			arch_timer_use_virtual ? "virt" : "phys" :
364 			"",
365 		     type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  "/" : "",
366 		     type & ARCH_MEM_TIMER ?
367 			arch_timer_mem_use_virtual ? "virt" : "phys" :
368 			"");
369 }
370 
371 u32 arch_timer_get_rate(void)
372 {
373 	return arch_timer_rate;
374 }
375 
376 static u64 arch_counter_get_cntvct_mem(void)
377 {
378 	u32 vct_lo, vct_hi, tmp_hi;
379 
380 	do {
381 		vct_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
382 		vct_lo = readl_relaxed(arch_counter_base + CNTVCT_LO);
383 		tmp_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
384 	} while (vct_hi != tmp_hi);
385 
386 	return ((u64) vct_hi << 32) | vct_lo;
387 }
388 
389 /*
390  * Default to cp15 based access because arm64 uses this function for
391  * sched_clock() before DT is probed and the cp15 method is guaranteed
392  * to exist on arm64. arm doesn't use this before DT is probed so even
393  * if we don't have the cp15 accessors we won't have a problem.
394  */
395 u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
396 
397 static cycle_t arch_counter_read(struct clocksource *cs)
398 {
399 	return arch_timer_read_counter();
400 }
401 
402 static cycle_t arch_counter_read_cc(const struct cyclecounter *cc)
403 {
404 	return arch_timer_read_counter();
405 }
406 
407 static struct clocksource clocksource_counter = {
408 	.name	= "arch_sys_counter",
409 	.rating	= 400,
410 	.read	= arch_counter_read,
411 	.mask	= CLOCKSOURCE_MASK(56),
412 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_SUSPEND_NONSTOP,
413 };
414 
415 static struct cyclecounter cyclecounter = {
416 	.read	= arch_counter_read_cc,
417 	.mask	= CLOCKSOURCE_MASK(56),
418 };
419 
420 static struct timecounter timecounter;
421 
422 struct timecounter *arch_timer_get_timecounter(void)
423 {
424 	return &timecounter;
425 }
426 
427 static void __init arch_counter_register(unsigned type)
428 {
429 	u64 start_count;
430 
431 	/* Register the CP15 based counter if we have one */
432 	if (type & ARCH_CP15_TIMER)
433 		arch_timer_read_counter = arch_counter_get_cntvct;
434 	else
435 		arch_timer_read_counter = arch_counter_get_cntvct_mem;
436 
437 	start_count = arch_timer_read_counter();
438 	clocksource_register_hz(&clocksource_counter, arch_timer_rate);
439 	cyclecounter.mult = clocksource_counter.mult;
440 	cyclecounter.shift = clocksource_counter.shift;
441 	timecounter_init(&timecounter, &cyclecounter, start_count);
442 
443 	/* 56 bits minimum, so we assume worst case rollover */
444 	sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
445 }
446 
447 static void arch_timer_stop(struct clock_event_device *clk)
448 {
449 	pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
450 		 clk->irq, smp_processor_id());
451 
452 	if (arch_timer_use_virtual)
453 		disable_percpu_irq(arch_timer_ppi[VIRT_PPI]);
454 	else {
455 		disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]);
456 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
457 			disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
458 	}
459 
460 	clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);
461 }
462 
463 static int arch_timer_cpu_notify(struct notifier_block *self,
464 					   unsigned long action, void *hcpu)
465 {
466 	/*
467 	 * Grab cpu pointer in each case to avoid spurious
468 	 * preemptible warnings
469 	 */
470 	switch (action & ~CPU_TASKS_FROZEN) {
471 	case CPU_STARTING:
472 		arch_timer_setup(this_cpu_ptr(arch_timer_evt));
473 		break;
474 	case CPU_DYING:
475 		arch_timer_stop(this_cpu_ptr(arch_timer_evt));
476 		break;
477 	}
478 
479 	return NOTIFY_OK;
480 }
481 
482 static struct notifier_block arch_timer_cpu_nb = {
483 	.notifier_call = arch_timer_cpu_notify,
484 };
485 
486 #ifdef CONFIG_CPU_PM
487 static unsigned int saved_cntkctl;
488 static int arch_timer_cpu_pm_notify(struct notifier_block *self,
489 				    unsigned long action, void *hcpu)
490 {
491 	if (action == CPU_PM_ENTER)
492 		saved_cntkctl = arch_timer_get_cntkctl();
493 	else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT)
494 		arch_timer_set_cntkctl(saved_cntkctl);
495 	return NOTIFY_OK;
496 }
497 
498 static struct notifier_block arch_timer_cpu_pm_notifier = {
499 	.notifier_call = arch_timer_cpu_pm_notify,
500 };
501 
502 static int __init arch_timer_cpu_pm_init(void)
503 {
504 	return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier);
505 }
506 #else
507 static int __init arch_timer_cpu_pm_init(void)
508 {
509 	return 0;
510 }
511 #endif
512 
513 static int __init arch_timer_register(void)
514 {
515 	int err;
516 	int ppi;
517 
518 	arch_timer_evt = alloc_percpu(struct clock_event_device);
519 	if (!arch_timer_evt) {
520 		err = -ENOMEM;
521 		goto out;
522 	}
523 
524 	if (arch_timer_use_virtual) {
525 		ppi = arch_timer_ppi[VIRT_PPI];
526 		err = request_percpu_irq(ppi, arch_timer_handler_virt,
527 					 "arch_timer", arch_timer_evt);
528 	} else {
529 		ppi = arch_timer_ppi[PHYS_SECURE_PPI];
530 		err = request_percpu_irq(ppi, arch_timer_handler_phys,
531 					 "arch_timer", arch_timer_evt);
532 		if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {
533 			ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
534 			err = request_percpu_irq(ppi, arch_timer_handler_phys,
535 						 "arch_timer", arch_timer_evt);
536 			if (err)
537 				free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
538 						arch_timer_evt);
539 		}
540 	}
541 
542 	if (err) {
543 		pr_err("arch_timer: can't register interrupt %d (%d)\n",
544 		       ppi, err);
545 		goto out_free;
546 	}
547 
548 	err = register_cpu_notifier(&arch_timer_cpu_nb);
549 	if (err)
550 		goto out_free_irq;
551 
552 	err = arch_timer_cpu_pm_init();
553 	if (err)
554 		goto out_unreg_notify;
555 
556 	/* Immediately configure the timer on the boot CPU */
557 	arch_timer_setup(this_cpu_ptr(arch_timer_evt));
558 
559 	return 0;
560 
561 out_unreg_notify:
562 	unregister_cpu_notifier(&arch_timer_cpu_nb);
563 out_free_irq:
564 	if (arch_timer_use_virtual)
565 		free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);
566 	else {
567 		free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
568 				arch_timer_evt);
569 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
570 			free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
571 					arch_timer_evt);
572 	}
573 
574 out_free:
575 	free_percpu(arch_timer_evt);
576 out:
577 	return err;
578 }
579 
580 static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
581 {
582 	int ret;
583 	irq_handler_t func;
584 	struct arch_timer *t;
585 
586 	t = kzalloc(sizeof(*t), GFP_KERNEL);
587 	if (!t)
588 		return -ENOMEM;
589 
590 	t->base = base;
591 	t->evt.irq = irq;
592 	__arch_timer_setup(ARCH_MEM_TIMER, &t->evt);
593 
594 	if (arch_timer_mem_use_virtual)
595 		func = arch_timer_handler_virt_mem;
596 	else
597 		func = arch_timer_handler_phys_mem;
598 
599 	ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &t->evt);
600 	if (ret) {
601 		pr_err("arch_timer: Failed to request mem timer irq\n");
602 		kfree(t);
603 	}
604 
605 	return ret;
606 }
607 
608 static const struct of_device_id arch_timer_of_match[] __initconst = {
609 	{ .compatible   = "arm,armv7-timer",    },
610 	{ .compatible   = "arm,armv8-timer",    },
611 	{},
612 };
613 
614 static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
615 	{ .compatible   = "arm,armv7-timer-mem", },
616 	{},
617 };
618 
619 static void __init arch_timer_common_init(void)
620 {
621 	unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
622 
623 	/* Wait until both nodes are probed if we have two timers */
624 	if ((arch_timers_present & mask) != mask) {
625 		if (of_find_matching_node(NULL, arch_timer_mem_of_match) &&
626 				!(arch_timers_present & ARCH_MEM_TIMER))
627 			return;
628 		if (of_find_matching_node(NULL, arch_timer_of_match) &&
629 				!(arch_timers_present & ARCH_CP15_TIMER))
630 			return;
631 	}
632 
633 	arch_timer_banner(arch_timers_present);
634 	arch_counter_register(arch_timers_present);
635 	arch_timer_arch_init();
636 }
637 
638 static void __init arch_timer_init(struct device_node *np)
639 {
640 	int i;
641 
642 	if (arch_timers_present & ARCH_CP15_TIMER) {
643 		pr_warn("arch_timer: multiple nodes in dt, skipping\n");
644 		return;
645 	}
646 
647 	arch_timers_present |= ARCH_CP15_TIMER;
648 	for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
649 		arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
650 	arch_timer_detect_rate(NULL, np);
651 
652 	/*
653 	 * If HYP mode is available, we know that the physical timer
654 	 * has been configured to be accessible from PL1. Use it, so
655 	 * that a guest can use the virtual timer instead.
656 	 *
657 	 * If no interrupt provided for virtual timer, we'll have to
658 	 * stick to the physical timer. It'd better be accessible...
659 	 */
660 	if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
661 		arch_timer_use_virtual = false;
662 
663 		if (!arch_timer_ppi[PHYS_SECURE_PPI] ||
664 		    !arch_timer_ppi[PHYS_NONSECURE_PPI]) {
665 			pr_warn("arch_timer: No interrupt available, giving up\n");
666 			return;
667 		}
668 	}
669 
670 	arch_timer_c3stop = !of_property_read_bool(np, "always-on");
671 
672 	arch_timer_register();
673 	arch_timer_common_init();
674 }
675 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init);
676 CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_init);
677 
678 static void __init arch_timer_mem_init(struct device_node *np)
679 {
680 	struct device_node *frame, *best_frame = NULL;
681 	void __iomem *cntctlbase, *base;
682 	unsigned int irq;
683 	u32 cnttidr;
684 
685 	arch_timers_present |= ARCH_MEM_TIMER;
686 	cntctlbase = of_iomap(np, 0);
687 	if (!cntctlbase) {
688 		pr_err("arch_timer: Can't find CNTCTLBase\n");
689 		return;
690 	}
691 
692 	cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
693 	iounmap(cntctlbase);
694 
695 	/*
696 	 * Try to find a virtual capable frame. Otherwise fall back to a
697 	 * physical capable frame.
698 	 */
699 	for_each_available_child_of_node(np, frame) {
700 		int n;
701 
702 		if (of_property_read_u32(frame, "frame-number", &n)) {
703 			pr_err("arch_timer: Missing frame-number\n");
704 			of_node_put(best_frame);
705 			of_node_put(frame);
706 			return;
707 		}
708 
709 		if (cnttidr & CNTTIDR_VIRT(n)) {
710 			of_node_put(best_frame);
711 			best_frame = frame;
712 			arch_timer_mem_use_virtual = true;
713 			break;
714 		}
715 		of_node_put(best_frame);
716 		best_frame = of_node_get(frame);
717 	}
718 
719 	base = arch_counter_base = of_iomap(best_frame, 0);
720 	if (!base) {
721 		pr_err("arch_timer: Can't map frame's registers\n");
722 		of_node_put(best_frame);
723 		return;
724 	}
725 
726 	if (arch_timer_mem_use_virtual)
727 		irq = irq_of_parse_and_map(best_frame, 1);
728 	else
729 		irq = irq_of_parse_and_map(best_frame, 0);
730 	of_node_put(best_frame);
731 	if (!irq) {
732 		pr_err("arch_timer: Frame missing %s irq",
733 		       arch_timer_mem_use_virtual ? "virt" : "phys");
734 		return;
735 	}
736 
737 	arch_timer_detect_rate(base, np);
738 	arch_timer_mem_register(base, irq);
739 	arch_timer_common_init();
740 }
741 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
742 		       arch_timer_mem_init);
743