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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
54enum {
55 MCT_INT_SPI,
56 MCT_INT_PPI
57};
58
59enum {
60 MCT_G0_IRQ,
61 MCT_G1_IRQ,
62 MCT_G2_IRQ,
63 MCT_G3_IRQ,
64 MCT_L0_IRQ,
65 MCT_L1_IRQ,
66 MCT_L2_IRQ,
67 MCT_L3_IRQ,
68 MCT_L4_IRQ,
69 MCT_L5_IRQ,
70 MCT_L6_IRQ,
71 MCT_L7_IRQ,
72 MCT_NR_IRQS,
73};
74
75static void __iomem *reg_base;
76static unsigned long clk_rate;
77static unsigned int mct_int_type;
78static int mct_irqs[MCT_NR_IRQS];
79
80struct mct_clock_event_device {
81 struct clock_event_device evt;
82 unsigned long base;
83 char name[10];
84};
85
86static void exynos4_mct_write(unsigned int value, unsigned long offset)
87{
88 unsigned long stat_addr;
89 u32 mask;
90 u32 i;
91
92 writel_relaxed(value, reg_base + offset);
93
94 if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) {
95 stat_addr = (offset & EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET;
96 switch (offset & ~EXYNOS4_MCT_L_MASK) {
97 case MCT_L_TCON_OFFSET:
98 mask = 1 << 3; /* L_TCON write status */
99 break;
100 case MCT_L_ICNTB_OFFSET:
101 mask = 1 << 1; /* L_ICNTB write status */
102 break;
103 case MCT_L_TCNTB_OFFSET:
104 mask = 1 << 0; /* L_TCNTB write status */
105 break;
106 default:
107 return;
108 }
109 } else {
110 switch (offset) {
111 case EXYNOS4_MCT_G_TCON:
112 stat_addr = EXYNOS4_MCT_G_WSTAT;
113 mask = 1 << 16; /* G_TCON write status */
114 break;
115 case EXYNOS4_MCT_G_COMP0_L:
116 stat_addr = EXYNOS4_MCT_G_WSTAT;
117 mask = 1 << 0; /* G_COMP0_L write status */
118 break;
119 case EXYNOS4_MCT_G_COMP0_U:
120 stat_addr = EXYNOS4_MCT_G_WSTAT;
121 mask = 1 << 1; /* G_COMP0_U write status */
122 break;
123 case EXYNOS4_MCT_G_COMP0_ADD_INCR:
124 stat_addr = EXYNOS4_MCT_G_WSTAT;
125 mask = 1 << 2; /* G_COMP0_ADD_INCR w status */
126 break;
127 case EXYNOS4_MCT_G_CNT_L:
128 stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
129 mask = 1 << 0; /* G_CNT_L write status */
130 break;
131 case EXYNOS4_MCT_G_CNT_U:
132 stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
133 mask = 1 << 1; /* G_CNT_U write status */
134 break;
135 default:
136 return;
137 }
138 }
139
140 /* Wait maximum 1 ms until written values are applied */
141 for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
142 if (readl_relaxed(reg_base + stat_addr) & mask) {
143 writel_relaxed(mask, reg_base + stat_addr);
144 return;
145 }
146
147 panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset);
148}
149
150/* Clocksource handling */
151static void exynos4_mct_frc_start(void)
152{
153 u32 reg;
154
155 reg = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
156 reg |= MCT_G_TCON_START;
157 exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
158}
159
160/**
161 * exynos4_read_count_64 - Read all 64-bits of the global counter
162 *
163 * This will read all 64-bits of the global counter taking care to make sure
164 * that the upper and lower half match. Note that reading the MCT can be quite
165 * slow (hundreds of nanoseconds) so you should use the 32-bit (lower half
166 * only) version when possible.
167 *
168 * Returns the number of cycles in the global counter.
169 */
170static u64 exynos4_read_count_64(void)
171{
172 unsigned int lo, hi;
173 u32 hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
174
175 do {
176 hi = hi2;
177 lo = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
178 hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
179 } while (hi != hi2);
180
181 return ((u64)hi << 32) | lo;
182}
183
184/**
185 * exynos4_read_count_32 - Read the lower 32-bits of the global counter
186 *
187 * This will read just the lower 32-bits of the global counter. This is marked
188 * as notrace so it can be used by the scheduler clock.
189 *
190 * Returns the number of cycles in the global counter (lower 32 bits).
191 */
192static u32 notrace exynos4_read_count_32(void)
193{
194 return readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
195}
196
197static u64 exynos4_frc_read(struct clocksource *cs)
198{
199 return exynos4_read_count_32();
200}
201
202static void exynos4_frc_resume(struct clocksource *cs)
203{
204 exynos4_mct_frc_start();
205}
206
207static struct clocksource mct_frc = {
208 .name = "mct-frc",
209 .rating = 450, /* use value higher than ARM arch timer */
210 .read = exynos4_frc_read,
211 .mask = CLOCKSOURCE_MASK(32),
212 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
213 .resume = exynos4_frc_resume,
214};
215
216static u64 notrace exynos4_read_sched_clock(void)
217{
218 return exynos4_read_count_32();
219}
220
221#if defined(CONFIG_ARM)
222static struct delay_timer exynos4_delay_timer;
223
224static cycles_t exynos4_read_current_timer(void)
225{
226 BUILD_BUG_ON_MSG(sizeof(cycles_t) != sizeof(u32),
227 "cycles_t needs to move to 32-bit for ARM64 usage");
228 return exynos4_read_count_32();
229}
230#endif
231
232static int __init exynos4_clocksource_init(void)
233{
234 exynos4_mct_frc_start();
235
236#if defined(CONFIG_ARM)
237 exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer;
238 exynos4_delay_timer.freq = clk_rate;
239 register_current_timer_delay(&exynos4_delay_timer);
240#endif
241
242 if (clocksource_register_hz(&mct_frc, clk_rate))
243 panic("%s: can't register clocksource\n", mct_frc.name);
244
245 sched_clock_register(exynos4_read_sched_clock, 32, clk_rate);
246
247 return 0;
248}
249
250static void exynos4_mct_comp0_stop(void)
251{
252 unsigned int tcon;
253
254 tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
255 tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
256
257 exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
258 exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
259}
260
261static void exynos4_mct_comp0_start(bool periodic, unsigned long cycles)
262{
263 unsigned int tcon;
264 u64 comp_cycle;
265
266 tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
267
268 if (periodic) {
269 tcon |= MCT_G_TCON_COMP0_AUTO_INC;
270 exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
271 }
272
273 comp_cycle = exynos4_read_count_64() + cycles;
274 exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
275 exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
276
277 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
278
279 tcon |= MCT_G_TCON_COMP0_ENABLE;
280 exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
281}
282
283static int exynos4_comp_set_next_event(unsigned long cycles,
284 struct clock_event_device *evt)
285{
286 exynos4_mct_comp0_start(false, cycles);
287
288 return 0;
289}
290
291static int mct_set_state_shutdown(struct clock_event_device *evt)
292{
293 exynos4_mct_comp0_stop();
294 return 0;
295}
296
297static int mct_set_state_periodic(struct clock_event_device *evt)
298{
299 unsigned long cycles_per_jiffy;
300
301 cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
302 >> evt->shift);
303 exynos4_mct_comp0_stop();
304 exynos4_mct_comp0_start(true, cycles_per_jiffy);
305 return 0;
306}
307
308static struct clock_event_device mct_comp_device = {
309 .name = "mct-comp",
310 .features = CLOCK_EVT_FEAT_PERIODIC |
311 CLOCK_EVT_FEAT_ONESHOT,
312 .rating = 250,
313 .set_next_event = exynos4_comp_set_next_event,
314 .set_state_periodic = mct_set_state_periodic,
315 .set_state_shutdown = mct_set_state_shutdown,
316 .set_state_oneshot = mct_set_state_shutdown,
317 .set_state_oneshot_stopped = mct_set_state_shutdown,
318 .tick_resume = mct_set_state_shutdown,
319};
320
321static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
322{
323 struct clock_event_device *evt = dev_id;
324
325 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
326
327 evt->event_handler(evt);
328
329 return IRQ_HANDLED;
330}
331
332static int exynos4_clockevent_init(void)
333{
334 mct_comp_device.cpumask = cpumask_of(0);
335 clockevents_config_and_register(&mct_comp_device, clk_rate,
336 0xf, 0xffffffff);
337 if (request_irq(mct_irqs[MCT_G0_IRQ], exynos4_mct_comp_isr,
338 IRQF_TIMER | IRQF_IRQPOLL, "mct_comp_irq",
339 &mct_comp_device))
340 pr_err("%s: request_irq() failed\n", "mct_comp_irq");
341
342 return 0;
343}
344
345static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
346
347/* Clock event handling */
348static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
349{
350 unsigned long tmp;
351 unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
352 unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
353
354 tmp = readl_relaxed(reg_base + offset);
355 if (tmp & mask) {
356 tmp &= ~mask;
357 exynos4_mct_write(tmp, offset);
358 }
359}
360
361static void exynos4_mct_tick_start(unsigned long cycles,
362 struct mct_clock_event_device *mevt)
363{
364 unsigned long tmp;
365
366 exynos4_mct_tick_stop(mevt);
367
368 tmp = (1 << 31) | cycles; /* MCT_L_UPDATE_ICNTB */
369
370 /* update interrupt count buffer */
371 exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
372
373 /* enable MCT tick interrupt */
374 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
375
376 tmp = readl_relaxed(reg_base + mevt->base + MCT_L_TCON_OFFSET);
377 tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
378 MCT_L_TCON_INTERVAL_MODE;
379 exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
380}
381
382static void exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
383{
384 /* Clear the MCT tick interrupt */
385 if (readl_relaxed(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1)
386 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
387}
388
389static int exynos4_tick_set_next_event(unsigned long cycles,
390 struct clock_event_device *evt)
391{
392 struct mct_clock_event_device *mevt;
393
394 mevt = container_of(evt, struct mct_clock_event_device, evt);
395 exynos4_mct_tick_start(cycles, mevt);
396 return 0;
397}
398
399static int set_state_shutdown(struct clock_event_device *evt)
400{
401 struct mct_clock_event_device *mevt;
402
403 mevt = container_of(evt, struct mct_clock_event_device, evt);
404 exynos4_mct_tick_stop(mevt);
405 exynos4_mct_tick_clear(mevt);
406 return 0;
407}
408
409static int set_state_periodic(struct clock_event_device *evt)
410{
411 struct mct_clock_event_device *mevt;
412 unsigned long cycles_per_jiffy;
413
414 mevt = container_of(evt, struct mct_clock_event_device, evt);
415 cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
416 >> evt->shift);
417 exynos4_mct_tick_stop(mevt);
418 exynos4_mct_tick_start(cycles_per_jiffy, mevt);
419 return 0;
420}
421
422static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
423{
424 struct mct_clock_event_device *mevt = dev_id;
425 struct clock_event_device *evt = &mevt->evt;
426
427 /*
428 * This is for supporting oneshot mode.
429 * Mct would generate interrupt periodically
430 * without explicit stopping.
431 */
432 if (!clockevent_state_periodic(&mevt->evt))
433 exynos4_mct_tick_stop(mevt);
434
435 exynos4_mct_tick_clear(mevt);
436
437 evt->event_handler(evt);
438
439 return IRQ_HANDLED;
440}
441
442static int exynos4_mct_starting_cpu(unsigned int cpu)
443{
444 struct mct_clock_event_device *mevt =
445 per_cpu_ptr(&percpu_mct_tick, cpu);
446 struct clock_event_device *evt = &mevt->evt;
447
448 mevt->base = EXYNOS4_MCT_L_BASE(cpu);
449 snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
450
451 evt->name = mevt->name;
452 evt->cpumask = cpumask_of(cpu);
453 evt->set_next_event = exynos4_tick_set_next_event;
454 evt->set_state_periodic = set_state_periodic;
455 evt->set_state_shutdown = set_state_shutdown;
456 evt->set_state_oneshot = set_state_shutdown;
457 evt->set_state_oneshot_stopped = set_state_shutdown;
458 evt->tick_resume = set_state_shutdown;
459 evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
460 evt->rating = 500; /* use value higher than ARM arch timer */
461
462 exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
463
464 if (mct_int_type == MCT_INT_SPI) {
465
466 if (evt->irq == -1)
467 return -EIO;
468
469 irq_force_affinity(evt->irq, cpumask_of(cpu));
470 enable_irq(evt->irq);
471 } else {
472 enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
473 }
474 clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
475 0xf, 0x7fffffff);
476
477 return 0;
478}
479
480static int exynos4_mct_dying_cpu(unsigned int cpu)
481{
482 struct mct_clock_event_device *mevt =
483 per_cpu_ptr(&percpu_mct_tick, cpu);
484 struct clock_event_device *evt = &mevt->evt;
485
486 evt->set_state_shutdown(evt);
487 if (mct_int_type == MCT_INT_SPI) {
488 if (evt->irq != -1)
489 disable_irq_nosync(evt->irq);
490 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
491 } else {
492 disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
493 }
494 return 0;
495}
496
497static int __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
498{
499 int err, cpu;
500 struct clk *mct_clk, *tick_clk;
501
502 tick_clk = of_clk_get_by_name(np, "fin_pll");
503 if (IS_ERR(tick_clk))
504 panic("%s: unable to determine tick clock rate\n", __func__);
505 clk_rate = clk_get_rate(tick_clk);
506
507 mct_clk = of_clk_get_by_name(np, "mct");
508 if (IS_ERR(mct_clk))
509 panic("%s: unable to retrieve mct clock instance\n", __func__);
510 clk_prepare_enable(mct_clk);
511
512 reg_base = base;
513 if (!reg_base)
514 panic("%s: unable to ioremap mct address space\n", __func__);
515
516 if (mct_int_type == MCT_INT_PPI) {
517
518 err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
519 exynos4_mct_tick_isr, "MCT",
520 &percpu_mct_tick);
521 WARN(err, "MCT: can't request IRQ %d (%d)\n",
522 mct_irqs[MCT_L0_IRQ], err);
523 } else {
524 for_each_possible_cpu(cpu) {
525 int mct_irq = mct_irqs[MCT_L0_IRQ + cpu];
526 struct mct_clock_event_device *pcpu_mevt =
527 per_cpu_ptr(&percpu_mct_tick, cpu);
528
529 pcpu_mevt->evt.irq = -1;
530
531 irq_set_status_flags(mct_irq, IRQ_NOAUTOEN);
532 if (request_irq(mct_irq,
533 exynos4_mct_tick_isr,
534 IRQF_TIMER | IRQF_NOBALANCING,
535 pcpu_mevt->name, pcpu_mevt)) {
536 pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
537 cpu);
538
539 continue;
540 }
541 pcpu_mevt->evt.irq = mct_irq;
542 }
543 }
544
545 /* Install hotplug callbacks which configure the timer on this CPU */
546 err = cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
547 "clockevents/exynos4/mct_timer:starting",
548 exynos4_mct_starting_cpu,
549 exynos4_mct_dying_cpu);
550 if (err)
551 goto out_irq;
552
553 return 0;
554
555out_irq:
556 if (mct_int_type == MCT_INT_PPI) {
557 free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
558 } else {
559 for_each_possible_cpu(cpu) {
560 struct mct_clock_event_device *pcpu_mevt =
561 per_cpu_ptr(&percpu_mct_tick, cpu);
562
563 if (pcpu_mevt->evt.irq != -1) {
564 free_irq(pcpu_mevt->evt.irq, pcpu_mevt);
565 pcpu_mevt->evt.irq = -1;
566 }
567 }
568 }
569 return err;
570}
571
572static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
573{
574 u32 nr_irqs, i;
575 int ret;
576
577 mct_int_type = int_type;
578
579 /* This driver uses only one global timer interrupt */
580 mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
581
582 /*
583 * Find out the number of local irqs specified. The local
584 * timer irqs are specified after the four global timer
585 * irqs are specified.
586 */
587 nr_irqs = of_irq_count(np);
588 for (i = MCT_L0_IRQ; i < nr_irqs; i++)
589 mct_irqs[i] = irq_of_parse_and_map(np, i);
590
591 ret = exynos4_timer_resources(np, of_iomap(np, 0));
592 if (ret)
593 return ret;
594
595 ret = exynos4_clocksource_init();
596 if (ret)
597 return ret;
598
599 return exynos4_clockevent_init();
600}
601
602
603static int __init mct_init_spi(struct device_node *np)
604{
605 return mct_init_dt(np, MCT_INT_SPI);
606}
607
608static int __init mct_init_ppi(struct device_node *np)
609{
610 return mct_init_dt(np, MCT_INT_PPI);
611}
612TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
613TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);