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