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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / clocksource / exynos_mct.c
bloba267fe31ef1330376b2bd03162374bf1dcf04b9b
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 enum {
55 MCT_INT_SPI,
56 MCT_INT_PPI
57 };
58
59 enum {
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
75 static void __iomem *reg_base;
76 static unsigned long clk_rate;
77 static unsigned int mct_int_type;
78 static int mct_irqs[MCT_NR_IRQS];
79
80 struct mct_clock_event_device {
81 struct clock_event_device evt;
82 unsigned long base;
83 char name[10];
84 };
85
86 static 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 */
151 static 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 */
170 static 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 */
192 static u32 notrace exynos4_read_count_32(void)
193 {
194 return readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
195 }
196
197 static u64 exynos4_frc_read(struct clocksource *cs)
198 {
199 return exynos4_read_count_32();
200 }
201
202 static void exynos4_frc_resume(struct clocksource *cs)
203 {
204 exynos4_mct_frc_start();
205 }
206
207 static 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
216 static u64 notrace exynos4_read_sched_clock(void)
217 {
218 return exynos4_read_count_32();
219 }
220
221 #if defined(CONFIG_ARM)
222 static struct delay_timer exynos4_delay_timer;
223
224 static 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
232 static 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
250 static 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
261 static 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
283 static 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
291 static int mct_set_state_shutdown(struct clock_event_device *evt)
292 {
293 exynos4_mct_comp0_stop();
294 return 0;
295 }
296
297 static 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
308 static 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
321 static 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
332 static struct irqaction mct_comp_event_irq = {
333 .name = "mct_comp_irq",
334 .flags = IRQF_TIMER | IRQF_IRQPOLL,
335 .handler = exynos4_mct_comp_isr,
336 .dev_id = &mct_comp_device,
337 };
338
339 static int exynos4_clockevent_init(void)
340 {
341 mct_comp_device.cpumask = cpumask_of(0);
342 clockevents_config_and_register(&mct_comp_device, clk_rate,
343 0xf, 0xffffffff);
344 setup_irq(mct_irqs[MCT_G0_IRQ], &mct_comp_event_irq);
345
346 return 0;
347 }
348
349 static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
350
351 /* Clock event handling */
352 static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
353 {
354 unsigned long tmp;
355 unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
356 unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
357
358 tmp = readl_relaxed(reg_base + offset);
359 if (tmp & mask) {
360 tmp &= ~mask;
361 exynos4_mct_write(tmp, offset);
362 }
363 }
364
365 static void exynos4_mct_tick_start(unsigned long cycles,
366 struct mct_clock_event_device *mevt)
367 {
368 unsigned long tmp;
369
370 exynos4_mct_tick_stop(mevt);
371
372 tmp = (1 << 31) | cycles; /* MCT_L_UPDATE_ICNTB */
373
374 /* update interrupt count buffer */
375 exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
376
377 /* enable MCT tick interrupt */
378 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
379
380 tmp = readl_relaxed(reg_base + mevt->base + MCT_L_TCON_OFFSET);
381 tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
382 MCT_L_TCON_INTERVAL_MODE;
383 exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
384 }
385
386 static void exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
387 {
388 /* Clear the MCT tick interrupt */
389 if (readl_relaxed(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1)
390 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
391 }
392
393 static int exynos4_tick_set_next_event(unsigned long cycles,
394 struct clock_event_device *evt)
395 {
396 struct mct_clock_event_device *mevt;
397
398 mevt = container_of(evt, struct mct_clock_event_device, evt);
399 exynos4_mct_tick_start(cycles, mevt);
400 return 0;
401 }
402
403 static int set_state_shutdown(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_stop(mevt);
409 exynos4_mct_tick_clear(mevt);
410 return 0;
411 }
412
413 static int set_state_periodic(struct clock_event_device *evt)
414 {
415 struct mct_clock_event_device *mevt;
416 unsigned long cycles_per_jiffy;
417
418 mevt = container_of(evt, struct mct_clock_event_device, evt);
419 cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
420 >> evt->shift);
421 exynos4_mct_tick_stop(mevt);
422 exynos4_mct_tick_start(cycles_per_jiffy, mevt);
423 return 0;
424 }
425
426 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
427 {
428 struct mct_clock_event_device *mevt = dev_id;
429 struct clock_event_device *evt = &mevt->evt;
430
431 /*
432 * This is for supporting oneshot mode.
433 * Mct would generate interrupt periodically
434 * without explicit stopping.
435 */
436 if (!clockevent_state_periodic(&mevt->evt))
437 exynos4_mct_tick_stop(mevt);
438
439 exynos4_mct_tick_clear(mevt);
440
441 evt->event_handler(evt);
442
443 return IRQ_HANDLED;
444 }
445
446 static int exynos4_mct_starting_cpu(unsigned int cpu)
447 {
448 struct mct_clock_event_device *mevt =
449 per_cpu_ptr(&percpu_mct_tick, cpu);
450 struct clock_event_device *evt = &mevt->evt;
451
452 mevt->base = EXYNOS4_MCT_L_BASE(cpu);
453 snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
454
455 evt->name = mevt->name;
456 evt->cpumask = cpumask_of(cpu);
457 evt->set_next_event = exynos4_tick_set_next_event;
458 evt->set_state_periodic = set_state_periodic;
459 evt->set_state_shutdown = set_state_shutdown;
460 evt->set_state_oneshot = set_state_shutdown;
461 evt->set_state_oneshot_stopped = set_state_shutdown;
462 evt->tick_resume = set_state_shutdown;
463 evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
464 evt->rating = 500; /* use value higher than ARM arch timer */
465
466 exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
467
468 if (mct_int_type == MCT_INT_SPI) {
469
470 if (evt->irq == -1)
471 return -EIO;
472
473 irq_force_affinity(evt->irq, cpumask_of(cpu));
474 enable_irq(evt->irq);
475 } else {
476 enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
477 }
478 clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
479 0xf, 0x7fffffff);
480
481 return 0;
482 }
483
484 static int exynos4_mct_dying_cpu(unsigned int cpu)
485 {
486 struct mct_clock_event_device *mevt =
487 per_cpu_ptr(&percpu_mct_tick, cpu);
488 struct clock_event_device *evt = &mevt->evt;
489
490 evt->set_state_shutdown(evt);
491 if (mct_int_type == MCT_INT_SPI) {
492 if (evt->irq != -1)
493 disable_irq_nosync(evt->irq);
494 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
495 } else {
496 disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
497 }
498 return 0;
499 }
500
501 static int __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
502 {
503 int err, cpu;
504 struct clk *mct_clk, *tick_clk;
505
506 tick_clk = of_clk_get_by_name(np, "fin_pll");
507 if (IS_ERR(tick_clk))
508 panic("%s: unable to determine tick clock rate\n", __func__);
509 clk_rate = clk_get_rate(tick_clk);
510
511 mct_clk = of_clk_get_by_name(np, "mct");
512 if (IS_ERR(mct_clk))
513 panic("%s: unable to retrieve mct clock instance\n", __func__);
514 clk_prepare_enable(mct_clk);
515
516 reg_base = base;
517 if (!reg_base)
518 panic("%s: unable to ioremap mct address space\n", __func__);
519
520 if (mct_int_type == MCT_INT_PPI) {
521
522 err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
523 exynos4_mct_tick_isr, "MCT",
524 &percpu_mct_tick);
525 WARN(err, "MCT: can't request IRQ %d (%d)\n",
526 mct_irqs[MCT_L0_IRQ], err);
527 } else {
528 for_each_possible_cpu(cpu) {
529 int mct_irq = mct_irqs[MCT_L0_IRQ + cpu];
530 struct mct_clock_event_device *pcpu_mevt =
531 per_cpu_ptr(&percpu_mct_tick, cpu);
532
533 pcpu_mevt->evt.irq = -1;
534
535 irq_set_status_flags(mct_irq, IRQ_NOAUTOEN);
536 if (request_irq(mct_irq,
537 exynos4_mct_tick_isr,
538 IRQF_TIMER | IRQF_NOBALANCING,
539 pcpu_mevt->name, pcpu_mevt)) {
540 pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
541 cpu);
542
543 continue;
544 }
545 pcpu_mevt->evt.irq = mct_irq;
546 }
547 }
548
549 /* Install hotplug callbacks which configure the timer on this CPU */
550 err = cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
551 "clockevents/exynos4/mct_timer:starting",
552 exynos4_mct_starting_cpu,
553 exynos4_mct_dying_cpu);
554 if (err)
555 goto out_irq;
556
557 return 0;
558
559 out_irq:
560 if (mct_int_type == MCT_INT_PPI) {
561 free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
562 } else {
563 for_each_possible_cpu(cpu) {
564 struct mct_clock_event_device *pcpu_mevt =
565 per_cpu_ptr(&percpu_mct_tick, cpu);
566
567 if (pcpu_mevt->evt.irq != -1) {
568 free_irq(pcpu_mevt->evt.irq, pcpu_mevt);
569 pcpu_mevt->evt.irq = -1;
570 }
571 }
572 }
573 return err;
574 }
575
576 static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
577 {
578 u32 nr_irqs, i;
579 int ret;
580
581 mct_int_type = int_type;
582
583 /* This driver uses only one global timer interrupt */
584 mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
585
586 /*
587 * Find out the number of local irqs specified. The local
588 * timer irqs are specified after the four global timer
589 * irqs are specified.
590 */
591 nr_irqs = of_irq_count(np);
592 for (i = MCT_L0_IRQ; i < nr_irqs; i++)
593 mct_irqs[i] = irq_of_parse_and_map(np, i);
594
595 ret = exynos4_timer_resources(np, of_iomap(np, 0));
596 if (ret)
597 return ret;
598
599 ret = exynos4_clocksource_init();
600 if (ret)
601 return ret;
602
603 return exynos4_clockevent_init();
604 }
605
606
607 static int __init mct_init_spi(struct device_node *np)
608 {
609 return mct_init_dt(np, MCT_INT_SPI);
610 }
611
612 static int __init mct_init_ppi(struct device_node *np)
613 {
614 return mct_init_dt(np, MCT_INT_PPI);
615 }
616 TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
617 TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
Linux with added FPC-III support