1 // SPDX-License-Identifier: GPL-2.0-only
2 /* linux/arch/arm/mach-exynos4/mct.c
3  *
4  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
5  *		http://www.samsung.com
6  *
7  * Exynos4 MCT(Multi-Core Timer) support
8 */
9 
10 #include <linux/interrupt.h>
11 #include <linux/irq.h>
12 #include <linux/err.h>
13 #include <linux/clk.h>
14 #include <linux/clockchips.h>
15 #include <linux/cpu.h>
16 #include <linux/delay.h>
17 #include <linux/percpu.h>
18 #include <linux/of.h>
19 #include <linux/of_irq.h>
20 #include <linux/of_address.h>
21 #include <linux/clocksource.h>
22 #include <linux/sched_clock.h>
23 
24 #define EXYNOS4_MCTREG(x)		(x)
25 #define EXYNOS4_MCT_G_CNT_L		EXYNOS4_MCTREG(0x100)
26 #define EXYNOS4_MCT_G_CNT_U		EXYNOS4_MCTREG(0x104)
27 #define EXYNOS4_MCT_G_CNT_WSTAT		EXYNOS4_MCTREG(0x110)
28 #define EXYNOS4_MCT_G_COMP0_L		EXYNOS4_MCTREG(0x200)
29 #define EXYNOS4_MCT_G_COMP0_U		EXYNOS4_MCTREG(0x204)
30 #define EXYNOS4_MCT_G_COMP0_ADD_INCR	EXYNOS4_MCTREG(0x208)
31 #define EXYNOS4_MCT_G_TCON		EXYNOS4_MCTREG(0x240)
32 #define EXYNOS4_MCT_G_INT_CSTAT		EXYNOS4_MCTREG(0x244)
33 #define EXYNOS4_MCT_G_INT_ENB		EXYNOS4_MCTREG(0x248)
34 #define EXYNOS4_MCT_G_WSTAT		EXYNOS4_MCTREG(0x24C)
35 #define _EXYNOS4_MCT_L_BASE		EXYNOS4_MCTREG(0x300)
36 #define EXYNOS4_MCT_L_BASE(x)		(_EXYNOS4_MCT_L_BASE + (0x100 * (x)))
37 #define EXYNOS4_MCT_L_MASK		(0xffffff00)
38 
39 #define MCT_L_TCNTB_OFFSET		(0x00)
40 #define MCT_L_ICNTB_OFFSET		(0x08)
41 #define MCT_L_TCON_OFFSET		(0x20)
42 #define MCT_L_INT_CSTAT_OFFSET		(0x30)
43 #define MCT_L_INT_ENB_OFFSET		(0x34)
44 #define MCT_L_WSTAT_OFFSET		(0x40)
45 #define MCT_G_TCON_START		(1 << 8)
46 #define MCT_G_TCON_COMP0_AUTO_INC	(1 << 1)
47 #define MCT_G_TCON_COMP0_ENABLE		(1 << 0)
48 #define MCT_L_TCON_INTERVAL_MODE	(1 << 2)
49 #define MCT_L_TCON_INT_START		(1 << 1)
50 #define MCT_L_TCON_TIMER_START		(1 << 0)
51 
52 #define TICK_BASE_CNT	1
53 
54 #ifdef CONFIG_ARM
55 /* Use values higher than ARM arch timer. See 6282edb72bed. */
56 #define MCT_CLKSOURCE_RATING		450
57 #define MCT_CLKEVENTS_RATING		500
58 #else
59 #define MCT_CLKSOURCE_RATING		350
60 #define MCT_CLKEVENTS_RATING		350
61 #endif
62 
63 /* There are four Global timers starting with 0 offset */
64 #define MCT_G0_IRQ	0
65 /* Local timers count starts after global timer count */
66 #define MCT_L0_IRQ	4
67 /* Max number of IRQ as per DT binding document */
68 #define MCT_NR_IRQS	20
69 /* Max number of local timers */
70 #define MCT_NR_LOCAL	(MCT_NR_IRQS - MCT_L0_IRQ)
71 
72 enum {
73 	MCT_INT_SPI,
74 	MCT_INT_PPI
75 };
76 
77 static void __iomem *reg_base;
78 static unsigned long clk_rate;
79 static unsigned int mct_int_type;
80 static int mct_irqs[MCT_NR_IRQS];
81 
82 struct mct_clock_event_device {
83 	struct clock_event_device evt;
84 	unsigned long base;
85 	/**
86 	 *  The length of the name must be adjusted if number of
87 	 *  local timer interrupts grow over two digits
88 	 */
89 	char name[11];
90 };
91 
92 static void exynos4_mct_write(unsigned int value, unsigned long offset)
93 {
94 	unsigned long stat_addr;
95 	u32 mask;
96 	u32 i;
97 
98 	writel_relaxed(value, reg_base + offset);
99 
100 	if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) {
101 		stat_addr = (offset & EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET;
102 		switch (offset & ~EXYNOS4_MCT_L_MASK) {
103 		case MCT_L_TCON_OFFSET:
104 			mask = 1 << 3;		/* L_TCON write status */
105 			break;
106 		case MCT_L_ICNTB_OFFSET:
107 			mask = 1 << 1;		/* L_ICNTB write status */
108 			break;
109 		case MCT_L_TCNTB_OFFSET:
110 			mask = 1 << 0;		/* L_TCNTB write status */
111 			break;
112 		default:
113 			return;
114 		}
115 	} else {
116 		switch (offset) {
117 		case EXYNOS4_MCT_G_TCON:
118 			stat_addr = EXYNOS4_MCT_G_WSTAT;
119 			mask = 1 << 16;		/* G_TCON write status */
120 			break;
121 		case EXYNOS4_MCT_G_COMP0_L:
122 			stat_addr = EXYNOS4_MCT_G_WSTAT;
123 			mask = 1 << 0;		/* G_COMP0_L write status */
124 			break;
125 		case EXYNOS4_MCT_G_COMP0_U:
126 			stat_addr = EXYNOS4_MCT_G_WSTAT;
127 			mask = 1 << 1;		/* G_COMP0_U write status */
128 			break;
129 		case EXYNOS4_MCT_G_COMP0_ADD_INCR:
130 			stat_addr = EXYNOS4_MCT_G_WSTAT;
131 			mask = 1 << 2;		/* G_COMP0_ADD_INCR w status */
132 			break;
133 		case EXYNOS4_MCT_G_CNT_L:
134 			stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
135 			mask = 1 << 0;		/* G_CNT_L write status */
136 			break;
137 		case EXYNOS4_MCT_G_CNT_U:
138 			stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
139 			mask = 1 << 1;		/* G_CNT_U write status */
140 			break;
141 		default:
142 			return;
143 		}
144 	}
145 
146 	/* Wait maximum 1 ms until written values are applied */
147 	for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
148 		if (readl_relaxed(reg_base + stat_addr) & mask) {
149 			writel_relaxed(mask, reg_base + stat_addr);
150 			return;
151 		}
152 
153 	panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset);
154 }
155 
156 /* Clocksource handling */
157 static void exynos4_mct_frc_start(void)
158 {
159 	u32 reg;
160 
161 	reg = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
162 	reg |= MCT_G_TCON_START;
163 	exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
164 }
165 
166 /**
167  * exynos4_read_count_64 - Read all 64-bits of the global counter
168  *
169  * This will read all 64-bits of the global counter taking care to make sure
170  * that the upper and lower half match.  Note that reading the MCT can be quite
171  * slow (hundreds of nanoseconds) so you should use the 32-bit (lower half
172  * only) version when possible.
173  *
174  * Returns the number of cycles in the global counter.
175  */
176 static u64 exynos4_read_count_64(void)
177 {
178 	unsigned int lo, hi;
179 	u32 hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
180 
181 	do {
182 		hi = hi2;
183 		lo = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
184 		hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
185 	} while (hi != hi2);
186 
187 	return ((u64)hi << 32) | lo;
188 }
189 
190 /**
191  * exynos4_read_count_32 - Read the lower 32-bits of the global counter
192  *
193  * This will read just the lower 32-bits of the global counter.  This is marked
194  * as notrace so it can be used by the scheduler clock.
195  *
196  * Returns the number of cycles in the global counter (lower 32 bits).
197  */
198 static u32 notrace exynos4_read_count_32(void)
199 {
200 	return readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
201 }
202 
203 static u64 exynos4_frc_read(struct clocksource *cs)
204 {
205 	return exynos4_read_count_32();
206 }
207 
208 static void exynos4_frc_resume(struct clocksource *cs)
209 {
210 	exynos4_mct_frc_start();
211 }
212 
213 static struct clocksource mct_frc = {
214 	.name		= "mct-frc",
215 	.rating		= MCT_CLKSOURCE_RATING,
216 	.read		= exynos4_frc_read,
217 	.mask		= CLOCKSOURCE_MASK(32),
218 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
219 	.resume		= exynos4_frc_resume,
220 };
221 
222 static u64 notrace exynos4_read_sched_clock(void)
223 {
224 	return exynos4_read_count_32();
225 }
226 
227 #if defined(CONFIG_ARM)
228 static struct delay_timer exynos4_delay_timer;
229 
230 static cycles_t exynos4_read_current_timer(void)
231 {
232 	BUILD_BUG_ON_MSG(sizeof(cycles_t) != sizeof(u32),
233 			 "cycles_t needs to move to 32-bit for ARM64 usage");
234 	return exynos4_read_count_32();
235 }
236 #endif
237 
238 static int __init exynos4_clocksource_init(bool frc_shared)
239 {
240 	/*
241 	 * When the frc is shared, the main processer should have already
242 	 * turned it on and we shouldn't be writing to TCON.
243 	 */
244 	if (frc_shared)
245 		mct_frc.resume = NULL;
246 	else
247 		exynos4_mct_frc_start();
248 
249 #if defined(CONFIG_ARM)
250 	exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer;
251 	exynos4_delay_timer.freq = clk_rate;
252 	register_current_timer_delay(&exynos4_delay_timer);
253 #endif
254 
255 	if (clocksource_register_hz(&mct_frc, clk_rate))
256 		panic("%s: can't register clocksource\n", mct_frc.name);
257 
258 	sched_clock_register(exynos4_read_sched_clock, 32, clk_rate);
259 
260 	return 0;
261 }
262 
263 static void exynos4_mct_comp0_stop(void)
264 {
265 	unsigned int tcon;
266 
267 	tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
268 	tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
269 
270 	exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
271 	exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
272 }
273 
274 static void exynos4_mct_comp0_start(bool periodic, unsigned long cycles)
275 {
276 	unsigned int tcon;
277 	u64 comp_cycle;
278 
279 	tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
280 
281 	if (periodic) {
282 		tcon |= MCT_G_TCON_COMP0_AUTO_INC;
283 		exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
284 	}
285 
286 	comp_cycle = exynos4_read_count_64() + cycles;
287 	exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
288 	exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
289 
290 	exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
291 
292 	tcon |= MCT_G_TCON_COMP0_ENABLE;
293 	exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
294 }
295 
296 static int exynos4_comp_set_next_event(unsigned long cycles,
297 				       struct clock_event_device *evt)
298 {
299 	exynos4_mct_comp0_start(false, cycles);
300 
301 	return 0;
302 }
303 
304 static int mct_set_state_shutdown(struct clock_event_device *evt)
305 {
306 	exynos4_mct_comp0_stop();
307 	return 0;
308 }
309 
310 static int mct_set_state_periodic(struct clock_event_device *evt)
311 {
312 	unsigned long cycles_per_jiffy;
313 
314 	cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
315 			    >> evt->shift);
316 	exynos4_mct_comp0_stop();
317 	exynos4_mct_comp0_start(true, cycles_per_jiffy);
318 	return 0;
319 }
320 
321 static struct clock_event_device mct_comp_device = {
322 	.name			= "mct-comp",
323 	.features		= CLOCK_EVT_FEAT_PERIODIC |
324 				  CLOCK_EVT_FEAT_ONESHOT,
325 	.rating			= 250,
326 	.set_next_event		= exynos4_comp_set_next_event,
327 	.set_state_periodic	= mct_set_state_periodic,
328 	.set_state_shutdown	= mct_set_state_shutdown,
329 	.set_state_oneshot	= mct_set_state_shutdown,
330 	.set_state_oneshot_stopped = mct_set_state_shutdown,
331 	.tick_resume		= mct_set_state_shutdown,
332 };
333 
334 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
335 {
336 	struct clock_event_device *evt = dev_id;
337 
338 	exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
339 
340 	evt->event_handler(evt);
341 
342 	return IRQ_HANDLED;
343 }
344 
345 static int exynos4_clockevent_init(void)
346 {
347 	mct_comp_device.cpumask = cpumask_of(0);
348 	clockevents_config_and_register(&mct_comp_device, clk_rate,
349 					0xf, 0xffffffff);
350 	if (request_irq(mct_irqs[MCT_G0_IRQ], exynos4_mct_comp_isr,
351 			IRQF_TIMER | IRQF_IRQPOLL, "mct_comp_irq",
352 			&mct_comp_device))
353 		pr_err("%s: request_irq() failed\n", "mct_comp_irq");
354 
355 	return 0;
356 }
357 
358 static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
359 
360 /* Clock event handling */
361 static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
362 {
363 	unsigned long tmp;
364 	unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
365 	unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
366 
367 	tmp = readl_relaxed(reg_base + offset);
368 	if (tmp & mask) {
369 		tmp &= ~mask;
370 		exynos4_mct_write(tmp, offset);
371 	}
372 }
373 
374 static void exynos4_mct_tick_start(unsigned long cycles,
375 				   struct mct_clock_event_device *mevt)
376 {
377 	unsigned long tmp;
378 
379 	exynos4_mct_tick_stop(mevt);
380 
381 	tmp = (1 << 31) | cycles;	/* MCT_L_UPDATE_ICNTB */
382 
383 	/* update interrupt count buffer */
384 	exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
385 
386 	/* enable MCT tick interrupt */
387 	exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
388 
389 	tmp = readl_relaxed(reg_base + mevt->base + MCT_L_TCON_OFFSET);
390 	tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
391 	       MCT_L_TCON_INTERVAL_MODE;
392 	exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
393 }
394 
395 static void exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
396 {
397 	/* Clear the MCT tick interrupt */
398 	if (readl_relaxed(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1)
399 		exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
400 }
401 
402 static int exynos4_tick_set_next_event(unsigned long cycles,
403 				       struct clock_event_device *evt)
404 {
405 	struct mct_clock_event_device *mevt;
406 
407 	mevt = container_of(evt, struct mct_clock_event_device, evt);
408 	exynos4_mct_tick_start(cycles, mevt);
409 	return 0;
410 }
411 
412 static int set_state_shutdown(struct clock_event_device *evt)
413 {
414 	struct mct_clock_event_device *mevt;
415 
416 	mevt = container_of(evt, struct mct_clock_event_device, evt);
417 	exynos4_mct_tick_stop(mevt);
418 	exynos4_mct_tick_clear(mevt);
419 	return 0;
420 }
421 
422 static int set_state_periodic(struct clock_event_device *evt)
423 {
424 	struct mct_clock_event_device *mevt;
425 	unsigned long cycles_per_jiffy;
426 
427 	mevt = container_of(evt, struct mct_clock_event_device, evt);
428 	cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
429 			    >> evt->shift);
430 	exynos4_mct_tick_stop(mevt);
431 	exynos4_mct_tick_start(cycles_per_jiffy, mevt);
432 	return 0;
433 }
434 
435 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
436 {
437 	struct mct_clock_event_device *mevt = dev_id;
438 	struct clock_event_device *evt = &mevt->evt;
439 
440 	/*
441 	 * This is for supporting oneshot mode.
442 	 * Mct would generate interrupt periodically
443 	 * without explicit stopping.
444 	 */
445 	if (!clockevent_state_periodic(&mevt->evt))
446 		exynos4_mct_tick_stop(mevt);
447 
448 	exynos4_mct_tick_clear(mevt);
449 
450 	evt->event_handler(evt);
451 
452 	return IRQ_HANDLED;
453 }
454 
455 static int exynos4_mct_starting_cpu(unsigned int cpu)
456 {
457 	struct mct_clock_event_device *mevt =
458 		per_cpu_ptr(&percpu_mct_tick, cpu);
459 	struct clock_event_device *evt = &mevt->evt;
460 
461 	snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
462 
463 	evt->name = mevt->name;
464 	evt->cpumask = cpumask_of(cpu);
465 	evt->set_next_event = exynos4_tick_set_next_event;
466 	evt->set_state_periodic = set_state_periodic;
467 	evt->set_state_shutdown = set_state_shutdown;
468 	evt->set_state_oneshot = set_state_shutdown;
469 	evt->set_state_oneshot_stopped = set_state_shutdown;
470 	evt->tick_resume = set_state_shutdown;
471 	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
472 			CLOCK_EVT_FEAT_PERCPU;
473 	evt->rating = MCT_CLKEVENTS_RATING;
474 
475 	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
476 
477 	if (mct_int_type == MCT_INT_SPI) {
478 
479 		if (evt->irq == -1)
480 			return -EIO;
481 
482 		irq_force_affinity(evt->irq, cpumask_of(cpu));
483 		enable_irq(evt->irq);
484 	} else {
485 		enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
486 	}
487 	clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
488 					0xf, 0x7fffffff);
489 
490 	return 0;
491 }
492 
493 static int exynos4_mct_dying_cpu(unsigned int cpu)
494 {
495 	struct mct_clock_event_device *mevt =
496 		per_cpu_ptr(&percpu_mct_tick, cpu);
497 	struct clock_event_device *evt = &mevt->evt;
498 
499 	evt->set_state_shutdown(evt);
500 	if (mct_int_type == MCT_INT_SPI) {
501 		if (evt->irq != -1)
502 			disable_irq_nosync(evt->irq);
503 		exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
504 	} else {
505 		disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
506 	}
507 	return 0;
508 }
509 
510 static int __init exynos4_timer_resources(struct device_node *np)
511 {
512 	struct clk *mct_clk, *tick_clk;
513 
514 	reg_base = of_iomap(np, 0);
515 	if (!reg_base)
516 		panic("%s: unable to ioremap mct address space\n", __func__);
517 
518 	tick_clk = of_clk_get_by_name(np, "fin_pll");
519 	if (IS_ERR(tick_clk))
520 		panic("%s: unable to determine tick clock rate\n", __func__);
521 	clk_rate = clk_get_rate(tick_clk);
522 
523 	mct_clk = of_clk_get_by_name(np, "mct");
524 	if (IS_ERR(mct_clk))
525 		panic("%s: unable to retrieve mct clock instance\n", __func__);
526 	clk_prepare_enable(mct_clk);
527 
528 	return 0;
529 }
530 
531 /**
532  * exynos4_timer_interrupts - initialize MCT interrupts
533  * @np: device node for MCT
534  * @int_type: interrupt type, MCT_INT_PPI or MCT_INT_SPI
535  * @local_idx: array mapping CPU numbers to local timer indices
536  * @nr_local: size of @local_idx array
537  */
538 static int __init exynos4_timer_interrupts(struct device_node *np,
539 					   unsigned int int_type,
540 					   const u32 *local_idx,
541 					   size_t nr_local)
542 {
543 	int nr_irqs, i, err, cpu;
544 
545 	mct_int_type = int_type;
546 
547 	/* This driver uses only one global timer interrupt */
548 	mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
549 
550 	/*
551 	 * Find out the number of local irqs specified. The local
552 	 * timer irqs are specified after the four global timer
553 	 * irqs are specified.
554 	 */
555 	nr_irqs = of_irq_count(np);
556 	if (nr_irqs > ARRAY_SIZE(mct_irqs)) {
557 		pr_err("exynos-mct: too many (%d) interrupts configured in DT\n",
558 			nr_irqs);
559 		nr_irqs = ARRAY_SIZE(mct_irqs);
560 	}
561 	for (i = MCT_L0_IRQ; i < nr_irqs; i++)
562 		mct_irqs[i] = irq_of_parse_and_map(np, i);
563 
564 	if (mct_int_type == MCT_INT_PPI) {
565 
566 		err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
567 					 exynos4_mct_tick_isr, "MCT",
568 					 &percpu_mct_tick);
569 		WARN(err, "MCT: can't request IRQ %d (%d)\n",
570 		     mct_irqs[MCT_L0_IRQ], err);
571 	} else {
572 		for_each_possible_cpu(cpu) {
573 			int mct_irq;
574 			unsigned int irq_idx;
575 			struct mct_clock_event_device *pcpu_mevt =
576 				per_cpu_ptr(&percpu_mct_tick, cpu);
577 
578 			if (cpu >= nr_local) {
579 				err = -EINVAL;
580 				goto out_irq;
581 			}
582 
583 			irq_idx = MCT_L0_IRQ + local_idx[cpu];
584 
585 			pcpu_mevt->evt.irq = -1;
586 			if (irq_idx >= ARRAY_SIZE(mct_irqs))
587 				break;
588 			mct_irq = mct_irqs[irq_idx];
589 
590 			irq_set_status_flags(mct_irq, IRQ_NOAUTOEN);
591 			if (request_irq(mct_irq,
592 					exynos4_mct_tick_isr,
593 					IRQF_TIMER | IRQF_NOBALANCING,
594 					pcpu_mevt->name, pcpu_mevt)) {
595 				pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
596 									cpu);
597 
598 				continue;
599 			}
600 			pcpu_mevt->evt.irq = mct_irq;
601 		}
602 	}
603 
604 	for_each_possible_cpu(cpu) {
605 		struct mct_clock_event_device *mevt = per_cpu_ptr(&percpu_mct_tick, cpu);
606 
607 		if (cpu >= nr_local) {
608 			err = -EINVAL;
609 			goto out_irq;
610 		}
611 
612 		mevt->base = EXYNOS4_MCT_L_BASE(local_idx[cpu]);
613 	}
614 
615 	/* Install hotplug callbacks which configure the timer on this CPU */
616 	err = cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
617 				"clockevents/exynos4/mct_timer:starting",
618 				exynos4_mct_starting_cpu,
619 				exynos4_mct_dying_cpu);
620 	if (err)
621 		goto out_irq;
622 
623 	return 0;
624 
625 out_irq:
626 	if (mct_int_type == MCT_INT_PPI) {
627 		free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
628 	} else {
629 		for_each_possible_cpu(cpu) {
630 			struct mct_clock_event_device *pcpu_mevt =
631 				per_cpu_ptr(&percpu_mct_tick, cpu);
632 
633 			if (pcpu_mevt->evt.irq != -1) {
634 				free_irq(pcpu_mevt->evt.irq, pcpu_mevt);
635 				pcpu_mevt->evt.irq = -1;
636 			}
637 		}
638 	}
639 	return err;
640 }
641 
642 static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
643 {
644 	bool frc_shared = of_property_read_bool(np, "samsung,frc-shared");
645 	u32 local_idx[MCT_NR_LOCAL] = {0};
646 	int nr_local;
647 	int ret;
648 
649 	nr_local = of_property_count_u32_elems(np, "samsung,local-timers");
650 	if (nr_local == 0)
651 		return -EINVAL;
652 	if (nr_local > 0) {
653 		if (nr_local > ARRAY_SIZE(local_idx))
654 			return -EINVAL;
655 
656 		ret = of_property_read_u32_array(np, "samsung,local-timers",
657 						 local_idx, nr_local);
658 		if (ret)
659 			return ret;
660 	} else {
661 		int i;
662 
663 		nr_local = ARRAY_SIZE(local_idx);
664 		for (i = 0; i < nr_local; i++)
665 			local_idx[i] = i;
666 	}
667 
668 	ret = exynos4_timer_resources(np);
669 	if (ret)
670 		return ret;
671 
672 	ret = exynos4_timer_interrupts(np, int_type, local_idx, nr_local);
673 	if (ret)
674 		return ret;
675 
676 	ret = exynos4_clocksource_init(frc_shared);
677 	if (ret)
678 		return ret;
679 
680 	/*
681 	 * When the FRC is shared with a main processor, this secondary
682 	 * processor cannot use the global comparator.
683 	 */
684 	if (frc_shared)
685 		return ret;
686 
687 	return exynos4_clockevent_init();
688 }
689 
690 
691 static int __init mct_init_spi(struct device_node *np)
692 {
693 	return mct_init_dt(np, MCT_INT_SPI);
694 }
695 
696 static int __init mct_init_ppi(struct device_node *np)
697 {
698 	return mct_init_dt(np, MCT_INT_PPI);
699 }
700 TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
701 TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
702