xref: /linux/drivers/clocksource/arm_arch_timer.c (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de) 
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/clocksource.h>
19 #include <linux/interrupt.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_address.h>
22 #include <linux/io.h>
23 #include <linux/slab.h>
24 #include <linux/sched_clock.h>
25 
26 #include <asm/arch_timer.h>
27 #include <asm/virt.h>
28 
29 #include <clocksource/arm_arch_timer.h>
30 
31 #define CNTTIDR		0x08
32 #define CNTTIDR_VIRT(n)	(BIT(1) << ((n) * 4))
33 
34 #define CNTVCT_LO	0x08
35 #define CNTVCT_HI	0x0c
36 #define CNTFRQ		0x10
37 #define CNTP_TVAL	0x28
38 #define CNTP_CTL	0x2c
39 #define CNTV_TVAL	0x38
40 #define CNTV_CTL	0x3c
41 
42 #define ARCH_CP15_TIMER	BIT(0)
43 #define ARCH_MEM_TIMER	BIT(1)
44 static unsigned arch_timers_present __initdata;
45 
46 static void __iomem *arch_counter_base;
47 
48 struct arch_timer {
49 	void __iomem *base;
50 	struct clock_event_device evt;
51 };
52 
53 #define to_arch_timer(e) container_of(e, struct arch_timer, evt)
54 
55 static u32 arch_timer_rate;
56 
57 enum ppi_nr {
58 	PHYS_SECURE_PPI,
59 	PHYS_NONSECURE_PPI,
60 	VIRT_PPI,
61 	HYP_PPI,
62 	MAX_TIMER_PPI
63 };
64 
65 static int arch_timer_ppi[MAX_TIMER_PPI];
66 
67 static struct clock_event_device __percpu *arch_timer_evt;
68 
69 static bool arch_timer_use_virtual = true;
70 static bool arch_timer_c3stop;
71 static bool arch_timer_mem_use_virtual;
72 
73 /*
74  * Architected system timer support.
75  */
76 
77 static __always_inline
78 void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
79 			  struct clock_event_device *clk)
80 {
81 	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
82 		struct arch_timer *timer = to_arch_timer(clk);
83 		switch (reg) {
84 		case ARCH_TIMER_REG_CTRL:
85 			writel_relaxed(val, timer->base + CNTP_CTL);
86 			break;
87 		case ARCH_TIMER_REG_TVAL:
88 			writel_relaxed(val, timer->base + CNTP_TVAL);
89 			break;
90 		}
91 	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
92 		struct arch_timer *timer = to_arch_timer(clk);
93 		switch (reg) {
94 		case ARCH_TIMER_REG_CTRL:
95 			writel_relaxed(val, timer->base + CNTV_CTL);
96 			break;
97 		case ARCH_TIMER_REG_TVAL:
98 			writel_relaxed(val, timer->base + CNTV_TVAL);
99 			break;
100 		}
101 	} else {
102 		arch_timer_reg_write_cp15(access, reg, val);
103 	}
104 }
105 
106 static __always_inline
107 u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
108 			struct clock_event_device *clk)
109 {
110 	u32 val;
111 
112 	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
113 		struct arch_timer *timer = to_arch_timer(clk);
114 		switch (reg) {
115 		case ARCH_TIMER_REG_CTRL:
116 			val = readl_relaxed(timer->base + CNTP_CTL);
117 			break;
118 		case ARCH_TIMER_REG_TVAL:
119 			val = readl_relaxed(timer->base + CNTP_TVAL);
120 			break;
121 		}
122 	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
123 		struct arch_timer *timer = to_arch_timer(clk);
124 		switch (reg) {
125 		case ARCH_TIMER_REG_CTRL:
126 			val = readl_relaxed(timer->base + CNTV_CTL);
127 			break;
128 		case ARCH_TIMER_REG_TVAL:
129 			val = readl_relaxed(timer->base + CNTV_TVAL);
130 			break;
131 		}
132 	} else {
133 		val = arch_timer_reg_read_cp15(access, reg);
134 	}
135 
136 	return val;
137 }
138 
139 static __always_inline irqreturn_t timer_handler(const int access,
140 					struct clock_event_device *evt)
141 {
142 	unsigned long ctrl;
143 
144 	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, evt);
145 	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
146 		ctrl |= ARCH_TIMER_CTRL_IT_MASK;
147 		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, evt);
148 		evt->event_handler(evt);
149 		return IRQ_HANDLED;
150 	}
151 
152 	return IRQ_NONE;
153 }
154 
155 static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id)
156 {
157 	struct clock_event_device *evt = dev_id;
158 
159 	return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);
160 }
161 
162 static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)
163 {
164 	struct clock_event_device *evt = dev_id;
165 
166 	return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
167 }
168 
169 static irqreturn_t arch_timer_handler_phys_mem(int irq, void *dev_id)
170 {
171 	struct clock_event_device *evt = dev_id;
172 
173 	return timer_handler(ARCH_TIMER_MEM_PHYS_ACCESS, evt);
174 }
175 
176 static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
177 {
178 	struct clock_event_device *evt = dev_id;
179 
180 	return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
181 }
182 
183 static __always_inline void timer_set_mode(const int access, int mode,
184 				  struct clock_event_device *clk)
185 {
186 	unsigned long ctrl;
187 	switch (mode) {
188 	case CLOCK_EVT_MODE_UNUSED:
189 	case CLOCK_EVT_MODE_SHUTDOWN:
190 		ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
191 		ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
192 		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
193 		break;
194 	default:
195 		break;
196 	}
197 }
198 
199 static void arch_timer_set_mode_virt(enum clock_event_mode mode,
200 				     struct clock_event_device *clk)
201 {
202 	timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode, clk);
203 }
204 
205 static void arch_timer_set_mode_phys(enum clock_event_mode mode,
206 				     struct clock_event_device *clk)
207 {
208 	timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode, clk);
209 }
210 
211 static void arch_timer_set_mode_virt_mem(enum clock_event_mode mode,
212 					 struct clock_event_device *clk)
213 {
214 	timer_set_mode(ARCH_TIMER_MEM_VIRT_ACCESS, mode, clk);
215 }
216 
217 static void arch_timer_set_mode_phys_mem(enum clock_event_mode mode,
218 					 struct clock_event_device *clk)
219 {
220 	timer_set_mode(ARCH_TIMER_MEM_PHYS_ACCESS, mode, clk);
221 }
222 
223 static __always_inline void set_next_event(const int access, unsigned long evt,
224 					   struct clock_event_device *clk)
225 {
226 	unsigned long ctrl;
227 	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
228 	ctrl |= ARCH_TIMER_CTRL_ENABLE;
229 	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
230 	arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt, clk);
231 	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
232 }
233 
234 static int arch_timer_set_next_event_virt(unsigned long evt,
235 					  struct clock_event_device *clk)
236 {
237 	set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
238 	return 0;
239 }
240 
241 static int arch_timer_set_next_event_phys(unsigned long evt,
242 					  struct clock_event_device *clk)
243 {
244 	set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
245 	return 0;
246 }
247 
248 static int arch_timer_set_next_event_virt_mem(unsigned long evt,
249 					      struct clock_event_device *clk)
250 {
251 	set_next_event(ARCH_TIMER_MEM_VIRT_ACCESS, evt, clk);
252 	return 0;
253 }
254 
255 static int arch_timer_set_next_event_phys_mem(unsigned long evt,
256 					      struct clock_event_device *clk)
257 {
258 	set_next_event(ARCH_TIMER_MEM_PHYS_ACCESS, evt, clk);
259 	return 0;
260 }
261 
262 static void __arch_timer_setup(unsigned type,
263 			       struct clock_event_device *clk)
264 {
265 	clk->features = CLOCK_EVT_FEAT_ONESHOT;
266 
267 	if (type == ARCH_CP15_TIMER) {
268 		if (arch_timer_c3stop)
269 			clk->features |= CLOCK_EVT_FEAT_C3STOP;
270 		clk->name = "arch_sys_timer";
271 		clk->rating = 450;
272 		clk->cpumask = cpumask_of(smp_processor_id());
273 		if (arch_timer_use_virtual) {
274 			clk->irq = arch_timer_ppi[VIRT_PPI];
275 			clk->set_mode = arch_timer_set_mode_virt;
276 			clk->set_next_event = arch_timer_set_next_event_virt;
277 		} else {
278 			clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
279 			clk->set_mode = arch_timer_set_mode_phys;
280 			clk->set_next_event = arch_timer_set_next_event_phys;
281 		}
282 	} else {
283 		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
284 		clk->name = "arch_mem_timer";
285 		clk->rating = 400;
286 		clk->cpumask = cpu_all_mask;
287 		if (arch_timer_mem_use_virtual) {
288 			clk->set_mode = arch_timer_set_mode_virt_mem;
289 			clk->set_next_event =
290 				arch_timer_set_next_event_virt_mem;
291 		} else {
292 			clk->set_mode = arch_timer_set_mode_phys_mem;
293 			clk->set_next_event =
294 				arch_timer_set_next_event_phys_mem;
295 		}
296 	}
297 
298 	clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, clk);
299 
300 	clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
301 }
302 
303 static void arch_timer_evtstrm_enable(int divider)
304 {
305 	u32 cntkctl = arch_timer_get_cntkctl();
306 
307 	cntkctl &= ~ARCH_TIMER_EVT_TRIGGER_MASK;
308 	/* Set the divider and enable virtual event stream */
309 	cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
310 			| ARCH_TIMER_VIRT_EVT_EN;
311 	arch_timer_set_cntkctl(cntkctl);
312 	elf_hwcap |= HWCAP_EVTSTRM;
313 #ifdef CONFIG_COMPAT
314 	compat_elf_hwcap |= COMPAT_HWCAP_EVTSTRM;
315 #endif
316 }
317 
318 static void arch_timer_configure_evtstream(void)
319 {
320 	int evt_stream_div, pos;
321 
322 	/* Find the closest power of two to the divisor */
323 	evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ;
324 	pos = fls(evt_stream_div);
325 	if (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))
326 		pos--;
327 	/* enable event stream */
328 	arch_timer_evtstrm_enable(min(pos, 15));
329 }
330 
331 static void arch_counter_set_user_access(void)
332 {
333 	u32 cntkctl = arch_timer_get_cntkctl();
334 
335 	/* Disable user access to the timers and the physical counter */
336 	/* Also disable virtual event stream */
337 	cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
338 			| ARCH_TIMER_USR_VT_ACCESS_EN
339 			| ARCH_TIMER_VIRT_EVT_EN
340 			| ARCH_TIMER_USR_PCT_ACCESS_EN);
341 
342 	/* Enable user access to the virtual counter */
343 	cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
344 
345 	arch_timer_set_cntkctl(cntkctl);
346 }
347 
348 static int arch_timer_setup(struct clock_event_device *clk)
349 {
350 	__arch_timer_setup(ARCH_CP15_TIMER, clk);
351 
352 	if (arch_timer_use_virtual)
353 		enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);
354 	else {
355 		enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0);
356 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
357 			enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
358 	}
359 
360 	arch_counter_set_user_access();
361 	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM))
362 		arch_timer_configure_evtstream();
363 
364 	return 0;
365 }
366 
367 static void
368 arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
369 {
370 	/* Who has more than one independent system counter? */
371 	if (arch_timer_rate)
372 		return;
373 
374 	/* Try to determine the frequency from the device tree or CNTFRQ */
375 	if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
376 		if (cntbase)
377 			arch_timer_rate = readl_relaxed(cntbase + CNTFRQ);
378 		else
379 			arch_timer_rate = arch_timer_get_cntfrq();
380 	}
381 
382 	/* Check the timer frequency. */
383 	if (arch_timer_rate == 0)
384 		pr_warn("Architected timer frequency not available\n");
385 }
386 
387 static void arch_timer_banner(unsigned type)
388 {
389 	pr_info("Architected %s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
390 		     type & ARCH_CP15_TIMER ? "cp15" : "",
391 		     type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  " and " : "",
392 		     type & ARCH_MEM_TIMER ? "mmio" : "",
393 		     (unsigned long)arch_timer_rate / 1000000,
394 		     (unsigned long)(arch_timer_rate / 10000) % 100,
395 		     type & ARCH_CP15_TIMER ?
396 			arch_timer_use_virtual ? "virt" : "phys" :
397 			"",
398 		     type == (ARCH_CP15_TIMER | ARCH_MEM_TIMER) ?  "/" : "",
399 		     type & ARCH_MEM_TIMER ?
400 			arch_timer_mem_use_virtual ? "virt" : "phys" :
401 			"");
402 }
403 
404 u32 arch_timer_get_rate(void)
405 {
406 	return arch_timer_rate;
407 }
408 
409 static u64 arch_counter_get_cntvct_mem(void)
410 {
411 	u32 vct_lo, vct_hi, tmp_hi;
412 
413 	do {
414 		vct_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
415 		vct_lo = readl_relaxed(arch_counter_base + CNTVCT_LO);
416 		tmp_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
417 	} while (vct_hi != tmp_hi);
418 
419 	return ((u64) vct_hi << 32) | vct_lo;
420 }
421 
422 /*
423  * Default to cp15 based access because arm64 uses this function for
424  * sched_clock() before DT is probed and the cp15 method is guaranteed
425  * to exist on arm64. arm doesn't use this before DT is probed so even
426  * if we don't have the cp15 accessors we won't have a problem.
427  */
428 u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
429 
430 static cycle_t arch_counter_read(struct clocksource *cs)
431 {
432 	return arch_timer_read_counter();
433 }
434 
435 static cycle_t arch_counter_read_cc(const struct cyclecounter *cc)
436 {
437 	return arch_timer_read_counter();
438 }
439 
440 static struct clocksource clocksource_counter = {
441 	.name	= "arch_sys_counter",
442 	.rating	= 400,
443 	.read	= arch_counter_read,
444 	.mask	= CLOCKSOURCE_MASK(56),
445 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_SUSPEND_NONSTOP,
446 };
447 
448 static struct cyclecounter cyclecounter = {
449 	.read	= arch_counter_read_cc,
450 	.mask	= CLOCKSOURCE_MASK(56),
451 };
452 
453 static struct timecounter timecounter;
454 
455 struct timecounter *arch_timer_get_timecounter(void)
456 {
457 	return &timecounter;
458 }
459 
460 static void __init arch_counter_register(unsigned type)
461 {
462 	u64 start_count;
463 
464 	/* Register the CP15 based counter if we have one */
465 	if (type & ARCH_CP15_TIMER) {
466 		if (IS_ENABLED(CONFIG_ARM64) || arch_timer_use_virtual)
467 			arch_timer_read_counter = arch_counter_get_cntvct;
468 		else
469 			arch_timer_read_counter = arch_counter_get_cntpct;
470 	} else {
471 		arch_timer_read_counter = arch_counter_get_cntvct_mem;
472 
473 		/* If the clocksource name is "arch_sys_counter" the
474 		 * VDSO will attempt to read the CP15-based counter.
475 		 * Ensure this does not happen when CP15-based
476 		 * counter is not available.
477 		 */
478 		clocksource_counter.name = "arch_mem_counter";
479 	}
480 
481 	start_count = arch_timer_read_counter();
482 	clocksource_register_hz(&clocksource_counter, arch_timer_rate);
483 	cyclecounter.mult = clocksource_counter.mult;
484 	cyclecounter.shift = clocksource_counter.shift;
485 	timecounter_init(&timecounter, &cyclecounter, start_count);
486 
487 	/* 56 bits minimum, so we assume worst case rollover */
488 	sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
489 }
490 
491 static void arch_timer_stop(struct clock_event_device *clk)
492 {
493 	pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
494 		 clk->irq, smp_processor_id());
495 
496 	if (arch_timer_use_virtual)
497 		disable_percpu_irq(arch_timer_ppi[VIRT_PPI]);
498 	else {
499 		disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]);
500 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
501 			disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
502 	}
503 
504 	clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);
505 }
506 
507 static int arch_timer_cpu_notify(struct notifier_block *self,
508 					   unsigned long action, void *hcpu)
509 {
510 	/*
511 	 * Grab cpu pointer in each case to avoid spurious
512 	 * preemptible warnings
513 	 */
514 	switch (action & ~CPU_TASKS_FROZEN) {
515 	case CPU_STARTING:
516 		arch_timer_setup(this_cpu_ptr(arch_timer_evt));
517 		break;
518 	case CPU_DYING:
519 		arch_timer_stop(this_cpu_ptr(arch_timer_evt));
520 		break;
521 	}
522 
523 	return NOTIFY_OK;
524 }
525 
526 static struct notifier_block arch_timer_cpu_nb = {
527 	.notifier_call = arch_timer_cpu_notify,
528 };
529 
530 #ifdef CONFIG_CPU_PM
531 static unsigned int saved_cntkctl;
532 static int arch_timer_cpu_pm_notify(struct notifier_block *self,
533 				    unsigned long action, void *hcpu)
534 {
535 	if (action == CPU_PM_ENTER)
536 		saved_cntkctl = arch_timer_get_cntkctl();
537 	else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT)
538 		arch_timer_set_cntkctl(saved_cntkctl);
539 	return NOTIFY_OK;
540 }
541 
542 static struct notifier_block arch_timer_cpu_pm_notifier = {
543 	.notifier_call = arch_timer_cpu_pm_notify,
544 };
545 
546 static int __init arch_timer_cpu_pm_init(void)
547 {
548 	return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier);
549 }
550 #else
551 static int __init arch_timer_cpu_pm_init(void)
552 {
553 	return 0;
554 }
555 #endif
556 
557 static int __init arch_timer_register(void)
558 {
559 	int err;
560 	int ppi;
561 
562 	arch_timer_evt = alloc_percpu(struct clock_event_device);
563 	if (!arch_timer_evt) {
564 		err = -ENOMEM;
565 		goto out;
566 	}
567 
568 	if (arch_timer_use_virtual) {
569 		ppi = arch_timer_ppi[VIRT_PPI];
570 		err = request_percpu_irq(ppi, arch_timer_handler_virt,
571 					 "arch_timer", arch_timer_evt);
572 	} else {
573 		ppi = arch_timer_ppi[PHYS_SECURE_PPI];
574 		err = request_percpu_irq(ppi, arch_timer_handler_phys,
575 					 "arch_timer", arch_timer_evt);
576 		if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {
577 			ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
578 			err = request_percpu_irq(ppi, arch_timer_handler_phys,
579 						 "arch_timer", arch_timer_evt);
580 			if (err)
581 				free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
582 						arch_timer_evt);
583 		}
584 	}
585 
586 	if (err) {
587 		pr_err("arch_timer: can't register interrupt %d (%d)\n",
588 		       ppi, err);
589 		goto out_free;
590 	}
591 
592 	err = register_cpu_notifier(&arch_timer_cpu_nb);
593 	if (err)
594 		goto out_free_irq;
595 
596 	err = arch_timer_cpu_pm_init();
597 	if (err)
598 		goto out_unreg_notify;
599 
600 	/* Immediately configure the timer on the boot CPU */
601 	arch_timer_setup(this_cpu_ptr(arch_timer_evt));
602 
603 	return 0;
604 
605 out_unreg_notify:
606 	unregister_cpu_notifier(&arch_timer_cpu_nb);
607 out_free_irq:
608 	if (arch_timer_use_virtual)
609 		free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);
610 	else {
611 		free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
612 				arch_timer_evt);
613 		if (arch_timer_ppi[PHYS_NONSECURE_PPI])
614 			free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
615 					arch_timer_evt);
616 	}
617 
618 out_free:
619 	free_percpu(arch_timer_evt);
620 out:
621 	return err;
622 }
623 
624 static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
625 {
626 	int ret;
627 	irq_handler_t func;
628 	struct arch_timer *t;
629 
630 	t = kzalloc(sizeof(*t), GFP_KERNEL);
631 	if (!t)
632 		return -ENOMEM;
633 
634 	t->base = base;
635 	t->evt.irq = irq;
636 	__arch_timer_setup(ARCH_MEM_TIMER, &t->evt);
637 
638 	if (arch_timer_mem_use_virtual)
639 		func = arch_timer_handler_virt_mem;
640 	else
641 		func = arch_timer_handler_phys_mem;
642 
643 	ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &t->evt);
644 	if (ret) {
645 		pr_err("arch_timer: Failed to request mem timer irq\n");
646 		kfree(t);
647 	}
648 
649 	return ret;
650 }
651 
652 static const struct of_device_id arch_timer_of_match[] __initconst = {
653 	{ .compatible   = "arm,armv7-timer",    },
654 	{ .compatible   = "arm,armv8-timer",    },
655 	{},
656 };
657 
658 static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
659 	{ .compatible   = "arm,armv7-timer-mem", },
660 	{},
661 };
662 
663 static bool __init
664 arch_timer_probed(int type, const struct of_device_id *matches)
665 {
666 	struct device_node *dn;
667 	bool probed = true;
668 
669 	dn = of_find_matching_node(NULL, matches);
670 	if (dn && of_device_is_available(dn) && !(arch_timers_present & type))
671 		probed = false;
672 	of_node_put(dn);
673 
674 	return probed;
675 }
676 
677 static void __init arch_timer_common_init(void)
678 {
679 	unsigned mask = ARCH_CP15_TIMER | ARCH_MEM_TIMER;
680 
681 	/* Wait until both nodes are probed if we have two timers */
682 	if ((arch_timers_present & mask) != mask) {
683 		if (!arch_timer_probed(ARCH_MEM_TIMER, arch_timer_mem_of_match))
684 			return;
685 		if (!arch_timer_probed(ARCH_CP15_TIMER, arch_timer_of_match))
686 			return;
687 	}
688 
689 	arch_timer_banner(arch_timers_present);
690 	arch_counter_register(arch_timers_present);
691 	arch_timer_arch_init();
692 }
693 
694 static void __init arch_timer_init(struct device_node *np)
695 {
696 	int i;
697 
698 	if (arch_timers_present & ARCH_CP15_TIMER) {
699 		pr_warn("arch_timer: multiple nodes in dt, skipping\n");
700 		return;
701 	}
702 
703 	arch_timers_present |= ARCH_CP15_TIMER;
704 	for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
705 		arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
706 	arch_timer_detect_rate(NULL, np);
707 
708 	/*
709 	 * If we cannot rely on firmware initializing the timer registers then
710 	 * we should use the physical timers instead.
711 	 */
712 	if (IS_ENABLED(CONFIG_ARM) &&
713 	    of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
714 			arch_timer_use_virtual = false;
715 
716 	/*
717 	 * If HYP mode is available, we know that the physical timer
718 	 * has been configured to be accessible from PL1. Use it, so
719 	 * that a guest can use the virtual timer instead.
720 	 *
721 	 * If no interrupt provided for virtual timer, we'll have to
722 	 * stick to the physical timer. It'd better be accessible...
723 	 */
724 	if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
725 		arch_timer_use_virtual = false;
726 
727 		if (!arch_timer_ppi[PHYS_SECURE_PPI] ||
728 		    !arch_timer_ppi[PHYS_NONSECURE_PPI]) {
729 			pr_warn("arch_timer: No interrupt available, giving up\n");
730 			return;
731 		}
732 	}
733 
734 	arch_timer_c3stop = !of_property_read_bool(np, "always-on");
735 
736 	arch_timer_register();
737 	arch_timer_common_init();
738 }
739 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init);
740 CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_init);
741 
742 static void __init arch_timer_mem_init(struct device_node *np)
743 {
744 	struct device_node *frame, *best_frame = NULL;
745 	void __iomem *cntctlbase, *base;
746 	unsigned int irq;
747 	u32 cnttidr;
748 
749 	arch_timers_present |= ARCH_MEM_TIMER;
750 	cntctlbase = of_iomap(np, 0);
751 	if (!cntctlbase) {
752 		pr_err("arch_timer: Can't find CNTCTLBase\n");
753 		return;
754 	}
755 
756 	cnttidr = readl_relaxed(cntctlbase + CNTTIDR);
757 	iounmap(cntctlbase);
758 
759 	/*
760 	 * Try to find a virtual capable frame. Otherwise fall back to a
761 	 * physical capable frame.
762 	 */
763 	for_each_available_child_of_node(np, frame) {
764 		int n;
765 
766 		if (of_property_read_u32(frame, "frame-number", &n)) {
767 			pr_err("arch_timer: Missing frame-number\n");
768 			of_node_put(best_frame);
769 			of_node_put(frame);
770 			return;
771 		}
772 
773 		if (cnttidr & CNTTIDR_VIRT(n)) {
774 			of_node_put(best_frame);
775 			best_frame = frame;
776 			arch_timer_mem_use_virtual = true;
777 			break;
778 		}
779 		of_node_put(best_frame);
780 		best_frame = of_node_get(frame);
781 	}
782 
783 	base = arch_counter_base = of_iomap(best_frame, 0);
784 	if (!base) {
785 		pr_err("arch_timer: Can't map frame's registers\n");
786 		of_node_put(best_frame);
787 		return;
788 	}
789 
790 	if (arch_timer_mem_use_virtual)
791 		irq = irq_of_parse_and_map(best_frame, 1);
792 	else
793 		irq = irq_of_parse_and_map(best_frame, 0);
794 	of_node_put(best_frame);
795 	if (!irq) {
796 		pr_err("arch_timer: Frame missing %s irq",
797 		       arch_timer_mem_use_virtual ? "virt" : "phys");
798 		return;
799 	}
800 
801 	arch_timer_detect_rate(base, np);
802 	arch_timer_mem_register(base, irq);
803 	arch_timer_common_init();
804 }
805 CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
806 		       arch_timer_mem_init);
807