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clocksource/drivers/exynos_mct: Increase priority over ARM arch timer
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1 /* linux/arch/arm/mach-exynos4/mct.c
2 *
3 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
4 * http://www.samsung.com
5 *
6 * EXYNOS4 MCT(Multi-Core Timer) support
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/sched.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/err.h>
17 #include <linux/clk.h>
18 #include <linux/clockchips.h>
19 #include <linux/cpu.h>
20 #include <linux/platform_device.h>
21 #include <linux/delay.h>
22 #include <linux/percpu.h>
23 #include <linux/of.h>
24 #include <linux/of_irq.h>
25 #include <linux/of_address.h>
26 #include <linux/clocksource.h>
27 #include <linux/sched_clock.h>
28
29 #define EXYNOS4_MCTREG(x) (x)
30 #define EXYNOS4_MCT_G_CNT_L EXYNOS4_MCTREG(0x100)
31 #define EXYNOS4_MCT_G_CNT_U EXYNOS4_MCTREG(0x104)
32 #define EXYNOS4_MCT_G_CNT_WSTAT EXYNOS4_MCTREG(0x110)
33 #define EXYNOS4_MCT_G_COMP0_L EXYNOS4_MCTREG(0x200)
34 #define EXYNOS4_MCT_G_COMP0_U EXYNOS4_MCTREG(0x204)
35 #define EXYNOS4_MCT_G_COMP0_ADD_INCR EXYNOS4_MCTREG(0x208)
36 #define EXYNOS4_MCT_G_TCON EXYNOS4_MCTREG(0x240)
37 #define EXYNOS4_MCT_G_INT_CSTAT EXYNOS4_MCTREG(0x244)
38 #define EXYNOS4_MCT_G_INT_ENB EXYNOS4_MCTREG(0x248)
39 #define EXYNOS4_MCT_G_WSTAT EXYNOS4_MCTREG(0x24C)
40 #define _EXYNOS4_MCT_L_BASE EXYNOS4_MCTREG(0x300)
41 #define EXYNOS4_MCT_L_BASE(x) (_EXYNOS4_MCT_L_BASE + (0x100 * x))
42 #define EXYNOS4_MCT_L_MASK (0xffffff00)
43
44 #define MCT_L_TCNTB_OFFSET (0x00)
45 #define MCT_L_ICNTB_OFFSET (0x08)
46 #define MCT_L_TCON_OFFSET (0x20)
47 #define MCT_L_INT_CSTAT_OFFSET (0x30)
48 #define MCT_L_INT_ENB_OFFSET (0x34)
49 #define MCT_L_WSTAT_OFFSET (0x40)
50 #define MCT_G_TCON_START (1 << 8)
51 #define MCT_G_TCON_COMP0_AUTO_INC (1 << 1)
52 #define MCT_G_TCON_COMP0_ENABLE (1 << 0)
53 #define MCT_L_TCON_INTERVAL_MODE (1 << 2)
54 #define MCT_L_TCON_INT_START (1 << 1)
55 #define MCT_L_TCON_TIMER_START (1 << 0)
56
57 #define TICK_BASE_CNT 1
58
59 enum {
60 MCT_INT_SPI,
61 MCT_INT_PPI
62 };
63
64 enum {
65 MCT_G0_IRQ,
66 MCT_G1_IRQ,
67 MCT_G2_IRQ,
68 MCT_G3_IRQ,
69 MCT_L0_IRQ,
70 MCT_L1_IRQ,
71 MCT_L2_IRQ,
72 MCT_L3_IRQ,
73 MCT_L4_IRQ,
74 MCT_L5_IRQ,
75 MCT_L6_IRQ,
76 MCT_L7_IRQ,
77 MCT_NR_IRQS,
78 };
79
80 static void __iomem *reg_base;
81 static unsigned long clk_rate;
82 static unsigned int mct_int_type;
83 static int mct_irqs[MCT_NR_IRQS];
84
85 struct mct_clock_event_device {
86 struct clock_event_device evt;
87 unsigned long base;
88 char name[10];
89 };
90
91 static void exynos4_mct_write(unsigned int value, unsigned long offset)
92 {
93 unsigned long stat_addr;
94 u32 mask;
95 u32 i;
96
97 writel_relaxed(value, reg_base + offset);
98
99 if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) {
100 stat_addr = (offset & EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET;
101 switch (offset & ~EXYNOS4_MCT_L_MASK) {
102 case MCT_L_TCON_OFFSET:
103 mask = 1 << 3; /* L_TCON write status */
104 break;
105 case MCT_L_ICNTB_OFFSET:
106 mask = 1 << 1; /* L_ICNTB write status */
107 break;
108 case MCT_L_TCNTB_OFFSET:
109 mask = 1 << 0; /* L_TCNTB write status */
110 break;
111 default:
112 return;
113 }
114 } else {
115 switch (offset) {
116 case EXYNOS4_MCT_G_TCON:
117 stat_addr = EXYNOS4_MCT_G_WSTAT;
118 mask = 1 << 16; /* G_TCON write status */
119 break;
120 case EXYNOS4_MCT_G_COMP0_L:
121 stat_addr = EXYNOS4_MCT_G_WSTAT;
122 mask = 1 << 0; /* G_COMP0_L write status */
123 break;
124 case EXYNOS4_MCT_G_COMP0_U:
125 stat_addr = EXYNOS4_MCT_G_WSTAT;
126 mask = 1 << 1; /* G_COMP0_U write status */
127 break;
128 case EXYNOS4_MCT_G_COMP0_ADD_INCR:
129 stat_addr = EXYNOS4_MCT_G_WSTAT;
130 mask = 1 << 2; /* G_COMP0_ADD_INCR w status */
131 break;
132 case EXYNOS4_MCT_G_CNT_L:
133 stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
134 mask = 1 << 0; /* G_CNT_L write status */
135 break;
136 case EXYNOS4_MCT_G_CNT_U:
137 stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
138 mask = 1 << 1; /* G_CNT_U write status */
139 break;
140 default:
141 return;
142 }
143 }
144
145 /* Wait maximum 1 ms until written values are applied */
146 for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
147 if (readl_relaxed(reg_base + stat_addr) & mask) {
148 writel_relaxed(mask, reg_base + stat_addr);
149 return;
150 }
151
152 panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset);
153 }
154
155 /* Clocksource handling */
156 static void exynos4_mct_frc_start(void)
157 {
158 u32 reg;
159
160 reg = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
161 reg |= MCT_G_TCON_START;
162 exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
163 }
164
165 /**
166 * exynos4_read_count_64 - Read all 64-bits of the global counter
167 *
168 * This will read all 64-bits of the global counter taking care to make sure
169 * that the upper and lower half match. Note that reading the MCT can be quite
170 * slow (hundreds of nanoseconds) so you should use the 32-bit (lower half
171 * only) version when possible.
172 *
173 * Returns the number of cycles in the global counter.
174 */
175 static u64 exynos4_read_count_64(void)
176 {
177 unsigned int lo, hi;
178 u32 hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
179
180 do {
181 hi = hi2;
182 lo = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
183 hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
184 } while (hi != hi2);
185
186 return ((u64)hi << 32) | lo;
187 }
188
189 /**
190 * exynos4_read_count_32 - Read the lower 32-bits of the global counter
191 *
192 * This will read just the lower 32-bits of the global counter. This is marked
193 * as notrace so it can be used by the scheduler clock.
194 *
195 * Returns the number of cycles in the global counter (lower 32 bits).
196 */
197 static u32 notrace exynos4_read_count_32(void)
198 {
199 return readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
200 }
201
202 static u64 exynos4_frc_read(struct clocksource *cs)
203 {
204 return exynos4_read_count_32();
205 }
206
207 static void exynos4_frc_resume(struct clocksource *cs)
208 {
209 exynos4_mct_frc_start();
210 }
211
212 static struct clocksource mct_frc = {
213 .name = "mct-frc",
214 .rating = 450, /* use value higher than ARM arch timer */
215 .read = exynos4_frc_read,
216 .mask = CLOCKSOURCE_MASK(32),
217 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
218 .resume = exynos4_frc_resume,
219 };
220
221 static u64 notrace exynos4_read_sched_clock(void)
222 {
223 return exynos4_read_count_32();
224 }
225
226 #if defined(CONFIG_ARM)
227 static struct delay_timer exynos4_delay_timer;
228
229 static cycles_t exynos4_read_current_timer(void)
230 {
231 BUILD_BUG_ON_MSG(sizeof(cycles_t) != sizeof(u32),
232 "cycles_t needs to move to 32-bit for ARM64 usage");
233 return exynos4_read_count_32();
234 }
235 #endif
236
237 static int __init exynos4_clocksource_init(void)
238 {
239 exynos4_mct_frc_start();
240
241 #if defined(CONFIG_ARM)
242 exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer;
243 exynos4_delay_timer.freq = clk_rate;
244 register_current_timer_delay(&exynos4_delay_timer);
245 #endif
246
247 if (clocksource_register_hz(&mct_frc, clk_rate))
248 panic("%s: can't register clocksource\n", mct_frc.name);
249
250 sched_clock_register(exynos4_read_sched_clock, 32, clk_rate);
251
252 return 0;
253 }
254
255 static void exynos4_mct_comp0_stop(void)
256 {
257 unsigned int tcon;
258
259 tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
260 tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
261
262 exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
263 exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
264 }
265
266 static void exynos4_mct_comp0_start(bool periodic, unsigned long cycles)
267 {
268 unsigned int tcon;
269 u64 comp_cycle;
270
271 tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
272
273 if (periodic) {
274 tcon |= MCT_G_TCON_COMP0_AUTO_INC;
275 exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
276 }
277
278 comp_cycle = exynos4_read_count_64() + cycles;
279 exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
280 exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
281
282 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
283
284 tcon |= MCT_G_TCON_COMP0_ENABLE;
285 exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
286 }
287
288 static int exynos4_comp_set_next_event(unsigned long cycles,
289 struct clock_event_device *evt)
290 {
291 exynos4_mct_comp0_start(false, cycles);
292
293 return 0;
294 }
295
296 static int mct_set_state_shutdown(struct clock_event_device *evt)
297 {
298 exynos4_mct_comp0_stop();
299 return 0;
300 }
301
302 static int mct_set_state_periodic(struct clock_event_device *evt)
303 {
304 unsigned long cycles_per_jiffy;
305
306 cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
307 >> evt->shift);
308 exynos4_mct_comp0_stop();
309 exynos4_mct_comp0_start(true, cycles_per_jiffy);
310 return 0;
311 }
312
313 static struct clock_event_device mct_comp_device = {
314 .name = "mct-comp",
315 .features = CLOCK_EVT_FEAT_PERIODIC |
316 CLOCK_EVT_FEAT_ONESHOT,
317 .rating = 250,
318 .set_next_event = exynos4_comp_set_next_event,
319 .set_state_periodic = mct_set_state_periodic,
320 .set_state_shutdown = mct_set_state_shutdown,
321 .set_state_oneshot = mct_set_state_shutdown,
322 .set_state_oneshot_stopped = mct_set_state_shutdown,
323 .tick_resume = mct_set_state_shutdown,
324 };
325
326 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
327 {
328 struct clock_event_device *evt = dev_id;
329
330 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
331
332 evt->event_handler(evt);
333
334 return IRQ_HANDLED;
335 }
336
337 static struct irqaction mct_comp_event_irq = {
338 .name = "mct_comp_irq",
339 .flags = IRQF_TIMER | IRQF_IRQPOLL,
340 .handler = exynos4_mct_comp_isr,
341 .dev_id = &mct_comp_device,
342 };
343
344 static int exynos4_clockevent_init(void)
345 {
346 mct_comp_device.cpumask = cpumask_of(0);
347 clockevents_config_and_register(&mct_comp_device, clk_rate,
348 0xf, 0xffffffff);
349 setup_irq(mct_irqs[MCT_G0_IRQ], &mct_comp_event_irq);
350
351 return 0;
352 }
353
354 static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
355
356 /* Clock event handling */
357 static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
358 {
359 unsigned long tmp;
360 unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
361 unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
362
363 tmp = readl_relaxed(reg_base + offset);
364 if (tmp & mask) {
365 tmp &= ~mask;
366 exynos4_mct_write(tmp, offset);
367 }
368 }
369
370 static void exynos4_mct_tick_start(unsigned long cycles,
371 struct mct_clock_event_device *mevt)
372 {
373 unsigned long tmp;
374
375 exynos4_mct_tick_stop(mevt);
376
377 tmp = (1 << 31) | cycles; /* MCT_L_UPDATE_ICNTB */
378
379 /* update interrupt count buffer */
380 exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
381
382 /* enable MCT tick interrupt */
383 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
384
385 tmp = readl_relaxed(reg_base + mevt->base + MCT_L_TCON_OFFSET);
386 tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
387 MCT_L_TCON_INTERVAL_MODE;
388 exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
389 }
390
391 static void exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
392 {
393 /* Clear the MCT tick interrupt */
394 if (readl_relaxed(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1)
395 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
396 }
397
398 static int exynos4_tick_set_next_event(unsigned long cycles,
399 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_start(cycles, mevt);
405 return 0;
406 }
407
408 static int set_state_shutdown(struct clock_event_device *evt)
409 {
410 struct mct_clock_event_device *mevt;
411
412 mevt = container_of(evt, struct mct_clock_event_device, evt);
413 exynos4_mct_tick_stop(mevt);
414 exynos4_mct_tick_clear(mevt);
415 return 0;
416 }
417
418 static int set_state_periodic(struct clock_event_device *evt)
419 {
420 struct mct_clock_event_device *mevt;
421 unsigned long cycles_per_jiffy;
422
423 mevt = container_of(evt, struct mct_clock_event_device, evt);
424 cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
425 >> evt->shift);
426 exynos4_mct_tick_stop(mevt);
427 exynos4_mct_tick_start(cycles_per_jiffy, mevt);
428 return 0;
429 }
430
431 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
432 {
433 struct mct_clock_event_device *mevt = dev_id;
434 struct clock_event_device *evt = &mevt->evt;
435
436 /*
437 * This is for supporting oneshot mode.
438 * Mct would generate interrupt periodically
439 * without explicit stopping.
440 */
441 if (!clockevent_state_periodic(&mevt->evt))
442 exynos4_mct_tick_stop(mevt);
443
444 exynos4_mct_tick_clear(mevt);
445
446 evt->event_handler(evt);
447
448 return IRQ_HANDLED;
449 }
450
451 static int exynos4_mct_starting_cpu(unsigned int cpu)
452 {
453 struct mct_clock_event_device *mevt =
454 per_cpu_ptr(&percpu_mct_tick, cpu);
455 struct clock_event_device *evt = &mevt->evt;
456
457 mevt->base = EXYNOS4_MCT_L_BASE(cpu);
458 snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
459
460 evt->name = mevt->name;
461 evt->cpumask = cpumask_of(cpu);
462 evt->set_next_event = exynos4_tick_set_next_event;
463 evt->set_state_periodic = set_state_periodic;
464 evt->set_state_shutdown = set_state_shutdown;
465 evt->set_state_oneshot = set_state_shutdown;
466 evt->set_state_oneshot_stopped = set_state_shutdown;
467 evt->tick_resume = set_state_shutdown;
468 evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
469 evt->rating = 500; /* use value higher than ARM arch timer */
470
471 exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
472
473 if (mct_int_type == MCT_INT_SPI) {
474
475 if (evt->irq == -1)
476 return -EIO;
477
478 irq_force_affinity(evt->irq, cpumask_of(cpu));
479 enable_irq(evt->irq);
480 } else {
481 enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
482 }
483 clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
484 0xf, 0x7fffffff);
485
486 return 0;
487 }
488
489 static int exynos4_mct_dying_cpu(unsigned int cpu)
490 {
491 struct mct_clock_event_device *mevt =
492 per_cpu_ptr(&percpu_mct_tick, cpu);
493 struct clock_event_device *evt = &mevt->evt;
494
495 evt->set_state_shutdown(evt);
496 if (mct_int_type == MCT_INT_SPI) {
497 if (evt->irq != -1)
498 disable_irq_nosync(evt->irq);
499 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
500 } else {
501 disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
502 }
503 return 0;
504 }
505
506 static int __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
507 {
508 int err, cpu;
509 struct clk *mct_clk, *tick_clk;
510
511 tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
512 clk_get(NULL, "fin_pll");
513 if (IS_ERR(tick_clk))
514 panic("%s: unable to determine tick clock rate\n", __func__);
515 clk_rate = clk_get_rate(tick_clk);
516
517 mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct");
518 if (IS_ERR(mct_clk))
519 panic("%s: unable to retrieve mct clock instance\n", __func__);
520 clk_prepare_enable(mct_clk);
521
522 reg_base = base;
523 if (!reg_base)
524 panic("%s: unable to ioremap mct address space\n", __func__);
525
526 if (mct_int_type == MCT_INT_PPI) {
527
528 err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
529 exynos4_mct_tick_isr, "MCT",
530 &percpu_mct_tick);
531 WARN(err, "MCT: can't request IRQ %d (%d)\n",
532 mct_irqs[MCT_L0_IRQ], err);
533 } else {
534 for_each_possible_cpu(cpu) {
535 int mct_irq = mct_irqs[MCT_L0_IRQ + cpu];
536 struct mct_clock_event_device *pcpu_mevt =
537 per_cpu_ptr(&percpu_mct_tick, cpu);
538
539 pcpu_mevt->evt.irq = -1;
540
541 irq_set_status_flags(mct_irq, IRQ_NOAUTOEN);
542 if (request_irq(mct_irq,
543 exynos4_mct_tick_isr,
544 IRQF_TIMER | IRQF_NOBALANCING,
545 pcpu_mevt->name, pcpu_mevt)) {
546 pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
547 cpu);
548
549 continue;
550 }
551 pcpu_mevt->evt.irq = mct_irq;
552 }
553 }
554
555 /* Install hotplug callbacks which configure the timer on this CPU */
556 err = cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
557 "clockevents/exynos4/mct_timer:starting",
558 exynos4_mct_starting_cpu,
559 exynos4_mct_dying_cpu);
560 if (err)
561 goto out_irq;
562
563 return 0;
564
565 out_irq:
566 free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
567 return err;
568 }
569
570 static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
571 {
572 u32 nr_irqs, i;
573 int ret;
574
575 mct_int_type = int_type;
576
577 /* This driver uses only one global timer interrupt */
578 mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
579
580 /*
581 * Find out the number of local irqs specified. The local
582 * timer irqs are specified after the four global timer
583 * irqs are specified.
584 */
585 #ifdef CONFIG_OF
586 nr_irqs = of_irq_count(np);
587 #else
588 nr_irqs = 0;
589 #endif
590 for (i = MCT_L0_IRQ; i < nr_irqs; i++)
591 mct_irqs[i] = irq_of_parse_and_map(np, i);
592
593 ret = exynos4_timer_resources(np, of_iomap(np, 0));
594 if (ret)
595 return ret;
596
597 ret = exynos4_clocksource_init();
598 if (ret)
599 return ret;
600
601 return exynos4_clockevent_init();
602 }
603
604
605 static int __init mct_init_spi(struct device_node *np)
606 {
607 return mct_init_dt(np, MCT_INT_SPI);
608 }
609
610 static int __init mct_init_ppi(struct device_node *np)
611 {
612 return mct_init_dt(np, MCT_INT_PPI);
613 }
614 TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
615 TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);