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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
59enum {
60 MCT_INT_SPI,
61 MCT_INT_PPI
62};
63
64enum {
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
80static void __iomem *reg_base;
81static unsigned long clk_rate;
82static unsigned int mct_int_type;
83static int mct_irqs[MCT_NR_IRQS];
84
85struct mct_clock_event_device {
86 struct clock_event_device evt;
87 unsigned long base;
88 char name[10];
89};
90
91static 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 */
156static 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 */
175static 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 ((cycle_t)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 */
197static u32 notrace exynos4_read_count_32(void)
198{
199 return readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
200}
201
202static cycle_t exynos4_frc_read(struct clocksource *cs)
203{
204 return exynos4_read_count_32();
205}
206
207static void exynos4_frc_resume(struct clocksource *cs)
208{
209 exynos4_mct_frc_start();
210}
211
212static struct clocksource mct_frc = {
213 .name = "mct-frc",
214 .rating = 400,
215 .read = exynos4_frc_read,
216 .mask = CLOCKSOURCE_MASK(32),
217 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
218 .resume = exynos4_frc_resume,
219};
220
221static u64 notrace exynos4_read_sched_clock(void)
222{
223 return exynos4_read_count_32();
224}
225
226static struct delay_timer exynos4_delay_timer;
227
228static cycles_t exynos4_read_current_timer(void)
229{
230 BUILD_BUG_ON_MSG(sizeof(cycles_t) != sizeof(u32),
231 "cycles_t needs to move to 32-bit for ARM64 usage");
232 return exynos4_read_count_32();
233}
234
235static void __init exynos4_clocksource_init(void)
236{
237 exynos4_mct_frc_start();
238
239 exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer;
240 exynos4_delay_timer.freq = clk_rate;
241 register_current_timer_delay(&exynos4_delay_timer);
242
243 if (clocksource_register_hz(&mct_frc, clk_rate))
244 panic("%s: can't register clocksource\n", mct_frc.name);
245
246 sched_clock_register(exynos4_read_sched_clock, 32, clk_rate);
247}
248
249static void exynos4_mct_comp0_stop(void)
250{
251 unsigned int tcon;
252
253 tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
254 tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
255
256 exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
257 exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
258}
259
260static void exynos4_mct_comp0_start(bool periodic, unsigned long cycles)
261{
262 unsigned int tcon;
263 cycle_t comp_cycle;
264
265 tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
266
267 if (periodic) {
268 tcon |= MCT_G_TCON_COMP0_AUTO_INC;
269 exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
270 }
271
272 comp_cycle = exynos4_read_count_64() + cycles;
273 exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
274 exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
275
276 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
277
278 tcon |= MCT_G_TCON_COMP0_ENABLE;
279 exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
280}
281
282static int exynos4_comp_set_next_event(unsigned long cycles,
283 struct clock_event_device *evt)
284{
285 exynos4_mct_comp0_start(false, cycles);
286
287 return 0;
288}
289
290static int mct_set_state_shutdown(struct clock_event_device *evt)
291{
292 exynos4_mct_comp0_stop();
293 return 0;
294}
295
296static int mct_set_state_periodic(struct clock_event_device *evt)
297{
298 unsigned long cycles_per_jiffy;
299
300 cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
301 >> evt->shift);
302 exynos4_mct_comp0_stop();
303 exynos4_mct_comp0_start(true, cycles_per_jiffy);
304 return 0;
305}
306
307static struct clock_event_device mct_comp_device = {
308 .name = "mct-comp",
309 .features = CLOCK_EVT_FEAT_PERIODIC |
310 CLOCK_EVT_FEAT_ONESHOT,
311 .rating = 250,
312 .set_next_event = exynos4_comp_set_next_event,
313 .set_state_periodic = mct_set_state_periodic,
314 .set_state_shutdown = mct_set_state_shutdown,
315 .set_state_oneshot = mct_set_state_shutdown,
316 .set_state_oneshot_stopped = mct_set_state_shutdown,
317 .tick_resume = mct_set_state_shutdown,
318};
319
320static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
321{
322 struct clock_event_device *evt = dev_id;
323
324 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
325
326 evt->event_handler(evt);
327
328 return IRQ_HANDLED;
329}
330
331static struct irqaction mct_comp_event_irq = {
332 .name = "mct_comp_irq",
333 .flags = IRQF_TIMER | IRQF_IRQPOLL,
334 .handler = exynos4_mct_comp_isr,
335 .dev_id = &mct_comp_device,
336};
337
338static void exynos4_clockevent_init(void)
339{
340 mct_comp_device.cpumask = cpumask_of(0);
341 clockevents_config_and_register(&mct_comp_device, clk_rate,
342 0xf, 0xffffffff);
343 setup_irq(mct_irqs[MCT_G0_IRQ], &mct_comp_event_irq);
344}
345
346static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
347
348/* Clock event handling */
349static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
350{
351 unsigned long tmp;
352 unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
353 unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
354
355 tmp = readl_relaxed(reg_base + offset);
356 if (tmp & mask) {
357 tmp &= ~mask;
358 exynos4_mct_write(tmp, offset);
359 }
360}
361
362static void exynos4_mct_tick_start(unsigned long cycles,
363 struct mct_clock_event_device *mevt)
364{
365 unsigned long tmp;
366
367 exynos4_mct_tick_stop(mevt);
368
369 tmp = (1 << 31) | cycles; /* MCT_L_UPDATE_ICNTB */
370
371 /* update interrupt count buffer */
372 exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
373
374 /* enable MCT tick interrupt */
375 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
376
377 tmp = readl_relaxed(reg_base + mevt->base + MCT_L_TCON_OFFSET);
378 tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
379 MCT_L_TCON_INTERVAL_MODE;
380 exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
381}
382
383static int exynos4_tick_set_next_event(unsigned long cycles,
384 struct clock_event_device *evt)
385{
386 struct mct_clock_event_device *mevt;
387
388 mevt = container_of(evt, struct mct_clock_event_device, evt);
389 exynos4_mct_tick_start(cycles, mevt);
390 return 0;
391}
392
393static int set_state_shutdown(struct clock_event_device *evt)
394{
395 struct mct_clock_event_device *mevt;
396
397 mevt = container_of(evt, struct mct_clock_event_device, evt);
398 exynos4_mct_tick_stop(mevt);
399 return 0;
400}
401
402static int set_state_periodic(struct clock_event_device *evt)
403{
404 struct mct_clock_event_device *mevt;
405 unsigned long cycles_per_jiffy;
406
407 mevt = container_of(evt, struct mct_clock_event_device, evt);
408 cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
409 >> evt->shift);
410 exynos4_mct_tick_stop(mevt);
411 exynos4_mct_tick_start(cycles_per_jiffy, mevt);
412 return 0;
413}
414
415static void exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
416{
417 /*
418 * This is for supporting oneshot mode.
419 * Mct would generate interrupt periodically
420 * without explicit stopping.
421 */
422 if (!clockevent_state_periodic(&mevt->evt))
423 exynos4_mct_tick_stop(mevt);
424
425 /* Clear the MCT tick interrupt */
426 if (readl_relaxed(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1)
427 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
428}
429
430static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
431{
432 struct mct_clock_event_device *mevt = dev_id;
433 struct clock_event_device *evt = &mevt->evt;
434
435 exynos4_mct_tick_clear(mevt);
436
437 evt->event_handler(evt);
438
439 return IRQ_HANDLED;
440}
441
442static int exynos4_local_timer_setup(struct mct_clock_event_device *mevt)
443{
444 struct clock_event_device *evt = &mevt->evt;
445 unsigned int cpu = smp_processor_id();
446
447 mevt->base = EXYNOS4_MCT_L_BASE(cpu);
448 snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
449
450 evt->name = mevt->name;
451 evt->cpumask = cpumask_of(cpu);
452 evt->set_next_event = exynos4_tick_set_next_event;
453 evt->set_state_periodic = set_state_periodic;
454 evt->set_state_shutdown = set_state_shutdown;
455 evt->set_state_oneshot = set_state_shutdown;
456 evt->set_state_oneshot_stopped = set_state_shutdown;
457 evt->tick_resume = set_state_shutdown;
458 evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
459 evt->rating = 450;
460
461 exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
462
463 if (mct_int_type == MCT_INT_SPI) {
464
465 if (evt->irq == -1)
466 return -EIO;
467
468 irq_force_affinity(evt->irq, cpumask_of(cpu));
469 enable_irq(evt->irq);
470 } else {
471 enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
472 }
473 clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
474 0xf, 0x7fffffff);
475
476 return 0;
477}
478
479static void exynos4_local_timer_stop(struct mct_clock_event_device *mevt)
480{
481 struct clock_event_device *evt = &mevt->evt;
482
483 evt->set_state_shutdown(evt);
484 if (mct_int_type == MCT_INT_SPI) {
485 if (evt->irq != -1)
486 disable_irq_nosync(evt->irq);
487 } else {
488 disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
489 }
490}
491
492static int exynos4_mct_cpu_notify(struct notifier_block *self,
493 unsigned long action, void *hcpu)
494{
495 struct mct_clock_event_device *mevt;
496
497 /*
498 * Grab cpu pointer in each case to avoid spurious
499 * preemptible warnings
500 */
501 switch (action & ~CPU_TASKS_FROZEN) {
502 case CPU_STARTING:
503 mevt = this_cpu_ptr(&percpu_mct_tick);
504 exynos4_local_timer_setup(mevt);
505 break;
506 case CPU_DYING:
507 mevt = this_cpu_ptr(&percpu_mct_tick);
508 exynos4_local_timer_stop(mevt);
509 break;
510 }
511
512 return NOTIFY_OK;
513}
514
515static struct notifier_block exynos4_mct_cpu_nb = {
516 .notifier_call = exynos4_mct_cpu_notify,
517};
518
519static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
520{
521 int err, cpu;
522 struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
523 struct clk *mct_clk, *tick_clk;
524
525 tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
526 clk_get(NULL, "fin_pll");
527 if (IS_ERR(tick_clk))
528 panic("%s: unable to determine tick clock rate\n", __func__);
529 clk_rate = clk_get_rate(tick_clk);
530
531 mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct");
532 if (IS_ERR(mct_clk))
533 panic("%s: unable to retrieve mct clock instance\n", __func__);
534 clk_prepare_enable(mct_clk);
535
536 reg_base = base;
537 if (!reg_base)
538 panic("%s: unable to ioremap mct address space\n", __func__);
539
540 if (mct_int_type == MCT_INT_PPI) {
541
542 err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
543 exynos4_mct_tick_isr, "MCT",
544 &percpu_mct_tick);
545 WARN(err, "MCT: can't request IRQ %d (%d)\n",
546 mct_irqs[MCT_L0_IRQ], err);
547 } else {
548 for_each_possible_cpu(cpu) {
549 int mct_irq = mct_irqs[MCT_L0_IRQ + cpu];
550 struct mct_clock_event_device *pcpu_mevt =
551 per_cpu_ptr(&percpu_mct_tick, cpu);
552
553 pcpu_mevt->evt.irq = -1;
554
555 irq_set_status_flags(mct_irq, IRQ_NOAUTOEN);
556 if (request_irq(mct_irq,
557 exynos4_mct_tick_isr,
558 IRQF_TIMER | IRQF_NOBALANCING,
559 pcpu_mevt->name, pcpu_mevt)) {
560 pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
561 cpu);
562
563 continue;
564 }
565 pcpu_mevt->evt.irq = mct_irq;
566 }
567 }
568
569 err = register_cpu_notifier(&exynos4_mct_cpu_nb);
570 if (err)
571 goto out_irq;
572
573 /* Immediately configure the timer on the boot CPU */
574 exynos4_local_timer_setup(mevt);
575 return;
576
577out_irq:
578 free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
579}
580
581static void __init mct_init_dt(struct device_node *np, unsigned int int_type)
582{
583 u32 nr_irqs, i;
584
585 mct_int_type = int_type;
586
587 /* This driver uses only one global timer interrupt */
588 mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
589
590 /*
591 * Find out the number of local irqs specified. The local
592 * timer irqs are specified after the four global timer
593 * irqs are specified.
594 */
595#ifdef CONFIG_OF
596 nr_irqs = of_irq_count(np);
597#else
598 nr_irqs = 0;
599#endif
600 for (i = MCT_L0_IRQ; i < nr_irqs; i++)
601 mct_irqs[i] = irq_of_parse_and_map(np, i);
602
603 exynos4_timer_resources(np, of_iomap(np, 0));
604 exynos4_clocksource_init();
605 exynos4_clockevent_init();
606}
607
608
609static void __init mct_init_spi(struct device_node *np)
610{
611 return mct_init_dt(np, MCT_INT_SPI);
612}
613
614static void __init mct_init_ppi(struct device_node *np)
615{
616 return mct_init_dt(np, MCT_INT_PPI);
617}
618CLOCKSOURCE_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
619CLOCKSOURCE_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);