1 // SPDX-License-Identifier: GPL-2.0-only
2 /* linux/arch/arm/mach-exynos4/mct.c
4 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
5 * http://www.samsung.com
7 * EXYNOS4 MCT(Multi-Core Timer) support
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>
19 #include <linux/of_irq.h>
20 #include <linux/of_address.h>
21 #include <linux/clocksource.h>
22 #include <linux/sched_clock.h>
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)
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)
52 #define TICK_BASE_CNT 1
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
];
80 struct mct_clock_event_device
{
81 struct clock_event_device evt
;
86 static void exynos4_mct_write(unsigned int value
, unsigned long offset
)
88 unsigned long stat_addr
;
92 writel_relaxed(value
, reg_base
+ offset
);
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 */
100 case MCT_L_ICNTB_OFFSET
:
101 mask
= 1 << 1; /* L_ICNTB write status */
103 case MCT_L_TCNTB_OFFSET
:
104 mask
= 1 << 0; /* L_TCNTB write status */
111 case EXYNOS4_MCT_G_TCON
:
112 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
113 mask
= 1 << 16; /* G_TCON write status */
115 case EXYNOS4_MCT_G_COMP0_L
:
116 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
117 mask
= 1 << 0; /* G_COMP0_L write status */
119 case EXYNOS4_MCT_G_COMP0_U
:
120 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
121 mask
= 1 << 1; /* G_COMP0_U write status */
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 */
127 case EXYNOS4_MCT_G_CNT_L
:
128 stat_addr
= EXYNOS4_MCT_G_CNT_WSTAT
;
129 mask
= 1 << 0; /* G_CNT_L write status */
131 case EXYNOS4_MCT_G_CNT_U
:
132 stat_addr
= EXYNOS4_MCT_G_CNT_WSTAT
;
133 mask
= 1 << 1; /* G_CNT_U write status */
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
);
147 panic("MCT hangs after writing %d (offset:0x%lx)\n", value
, offset
);
150 /* Clocksource handling */
151 static void exynos4_mct_frc_start(void)
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
);
161 * exynos4_read_count_64 - Read all 64-bits of the global counter
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.
168 * Returns the number of cycles in the global counter.
170 static u64
exynos4_read_count_64(void)
173 u32 hi2
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_U
);
177 lo
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_L
);
178 hi2
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_U
);
181 return ((u64
)hi
<< 32) | lo
;
185 * exynos4_read_count_32 - Read the lower 32-bits of the global counter
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.
190 * Returns the number of cycles in the global counter (lower 32 bits).
192 static u32 notrace
exynos4_read_count_32(void)
194 return readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_L
);
197 static u64
exynos4_frc_read(struct clocksource
*cs
)
199 return exynos4_read_count_32();
202 static void exynos4_frc_resume(struct clocksource
*cs
)
204 exynos4_mct_frc_start();
207 static struct clocksource 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
,
216 static u64 notrace
exynos4_read_sched_clock(void)
218 return exynos4_read_count_32();
221 #if defined(CONFIG_ARM)
222 static struct delay_timer exynos4_delay_timer
;
224 static cycles_t
exynos4_read_current_timer(void)
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();
232 static int __init
exynos4_clocksource_init(void)
234 exynos4_mct_frc_start();
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
);
242 if (clocksource_register_hz(&mct_frc
, clk_rate
))
243 panic("%s: can't register clocksource\n", mct_frc
.name
);
245 sched_clock_register(exynos4_read_sched_clock
, 32, clk_rate
);
250 static void exynos4_mct_comp0_stop(void)
254 tcon
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_TCON
);
255 tcon
&= ~(MCT_G_TCON_COMP0_ENABLE
| MCT_G_TCON_COMP0_AUTO_INC
);
257 exynos4_mct_write(tcon
, EXYNOS4_MCT_G_TCON
);
258 exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB
);
261 static void exynos4_mct_comp0_start(bool periodic
, unsigned long cycles
)
266 tcon
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_TCON
);
269 tcon
|= MCT_G_TCON_COMP0_AUTO_INC
;
270 exynos4_mct_write(cycles
, EXYNOS4_MCT_G_COMP0_ADD_INCR
);
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
);
277 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB
);
279 tcon
|= MCT_G_TCON_COMP0_ENABLE
;
280 exynos4_mct_write(tcon
, EXYNOS4_MCT_G_TCON
);
283 static int exynos4_comp_set_next_event(unsigned long cycles
,
284 struct clock_event_device
*evt
)
286 exynos4_mct_comp0_start(false, cycles
);
291 static int mct_set_state_shutdown(struct clock_event_device
*evt
)
293 exynos4_mct_comp0_stop();
297 static int mct_set_state_periodic(struct clock_event_device
*evt
)
299 unsigned long cycles_per_jiffy
;
301 cycles_per_jiffy
= (((unsigned long long)NSEC_PER_SEC
/ HZ
* evt
->mult
)
303 exynos4_mct_comp0_stop();
304 exynos4_mct_comp0_start(true, cycles_per_jiffy
);
308 static struct clock_event_device mct_comp_device
= {
310 .features
= CLOCK_EVT_FEAT_PERIODIC
|
311 CLOCK_EVT_FEAT_ONESHOT
,
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
,
321 static irqreturn_t
exynos4_mct_comp_isr(int irq
, void *dev_id
)
323 struct clock_event_device
*evt
= dev_id
;
325 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT
);
327 evt
->event_handler(evt
);
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
,
339 static int exynos4_clockevent_init(void)
341 mct_comp_device
.cpumask
= cpumask_of(0);
342 clockevents_config_and_register(&mct_comp_device
, clk_rate
,
344 setup_irq(mct_irqs
[MCT_G0_IRQ
], &mct_comp_event_irq
);
349 static DEFINE_PER_CPU(struct mct_clock_event_device
, percpu_mct_tick
);
351 /* Clock event handling */
352 static void exynos4_mct_tick_stop(struct mct_clock_event_device
*mevt
)
355 unsigned long mask
= MCT_L_TCON_INT_START
| MCT_L_TCON_TIMER_START
;
356 unsigned long offset
= mevt
->base
+ MCT_L_TCON_OFFSET
;
358 tmp
= readl_relaxed(reg_base
+ offset
);
361 exynos4_mct_write(tmp
, offset
);
365 static void exynos4_mct_tick_start(unsigned long cycles
,
366 struct mct_clock_event_device
*mevt
)
370 exynos4_mct_tick_stop(mevt
);
372 tmp
= (1 << 31) | cycles
; /* MCT_L_UPDATE_ICNTB */
374 /* update interrupt count buffer */
375 exynos4_mct_write(tmp
, mevt
->base
+ MCT_L_ICNTB_OFFSET
);
377 /* enable MCT tick interrupt */
378 exynos4_mct_write(0x1, mevt
->base
+ MCT_L_INT_ENB_OFFSET
);
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
);
386 static void exynos4_mct_tick_clear(struct mct_clock_event_device
*mevt
)
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
);
393 static int exynos4_tick_set_next_event(unsigned long cycles
,
394 struct clock_event_device
*evt
)
396 struct mct_clock_event_device
*mevt
;
398 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
399 exynos4_mct_tick_start(cycles
, mevt
);
403 static int set_state_shutdown(struct clock_event_device
*evt
)
405 struct mct_clock_event_device
*mevt
;
407 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
408 exynos4_mct_tick_stop(mevt
);
409 exynos4_mct_tick_clear(mevt
);
413 static int set_state_periodic(struct clock_event_device
*evt
)
415 struct mct_clock_event_device
*mevt
;
416 unsigned long cycles_per_jiffy
;
418 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
419 cycles_per_jiffy
= (((unsigned long long)NSEC_PER_SEC
/ HZ
* evt
->mult
)
421 exynos4_mct_tick_stop(mevt
);
422 exynos4_mct_tick_start(cycles_per_jiffy
, mevt
);
426 static irqreturn_t
exynos4_mct_tick_isr(int irq
, void *dev_id
)
428 struct mct_clock_event_device
*mevt
= dev_id
;
429 struct clock_event_device
*evt
= &mevt
->evt
;
432 * This is for supporting oneshot mode.
433 * Mct would generate interrupt periodically
434 * without explicit stopping.
436 if (!clockevent_state_periodic(&mevt
->evt
))
437 exynos4_mct_tick_stop(mevt
);
439 exynos4_mct_tick_clear(mevt
);
441 evt
->event_handler(evt
);
446 static int exynos4_mct_starting_cpu(unsigned int cpu
)
448 struct mct_clock_event_device
*mevt
=
449 per_cpu_ptr(&percpu_mct_tick
, cpu
);
450 struct clock_event_device
*evt
= &mevt
->evt
;
452 mevt
->base
= EXYNOS4_MCT_L_BASE(cpu
);
453 snprintf(mevt
->name
, sizeof(mevt
->name
), "mct_tick%d", cpu
);
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 */
466 exynos4_mct_write(TICK_BASE_CNT
, mevt
->base
+ MCT_L_TCNTB_OFFSET
);
468 if (mct_int_type
== MCT_INT_SPI
) {
473 irq_force_affinity(evt
->irq
, cpumask_of(cpu
));
474 enable_irq(evt
->irq
);
476 enable_percpu_irq(mct_irqs
[MCT_L0_IRQ
], 0);
478 clockevents_config_and_register(evt
, clk_rate
/ (TICK_BASE_CNT
+ 1),
484 static int exynos4_mct_dying_cpu(unsigned int cpu
)
486 struct mct_clock_event_device
*mevt
=
487 per_cpu_ptr(&percpu_mct_tick
, cpu
);
488 struct clock_event_device
*evt
= &mevt
->evt
;
490 evt
->set_state_shutdown(evt
);
491 if (mct_int_type
== MCT_INT_SPI
) {
493 disable_irq_nosync(evt
->irq
);
494 exynos4_mct_write(0x1, mevt
->base
+ MCT_L_INT_CSTAT_OFFSET
);
496 disable_percpu_irq(mct_irqs
[MCT_L0_IRQ
]);
501 static int __init
exynos4_timer_resources(struct device_node
*np
, void __iomem
*base
)
504 struct clk
*mct_clk
, *tick_clk
;
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
);
511 mct_clk
= of_clk_get_by_name(np
, "mct");
513 panic("%s: unable to retrieve mct clock instance\n", __func__
);
514 clk_prepare_enable(mct_clk
);
518 panic("%s: unable to ioremap mct address space\n", __func__
);
520 if (mct_int_type
== MCT_INT_PPI
) {
522 err
= request_percpu_irq(mct_irqs
[MCT_L0_IRQ
],
523 exynos4_mct_tick_isr
, "MCT",
525 WARN(err
, "MCT: can't request IRQ %d (%d)\n",
526 mct_irqs
[MCT_L0_IRQ
], err
);
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
);
533 pcpu_mevt
->evt
.irq
= -1;
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",
545 pcpu_mevt
->evt
.irq
= mct_irq
;
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
);
560 if (mct_int_type
== MCT_INT_PPI
) {
561 free_percpu_irq(mct_irqs
[MCT_L0_IRQ
], &percpu_mct_tick
);
563 for_each_possible_cpu(cpu
) {
564 struct mct_clock_event_device
*pcpu_mevt
=
565 per_cpu_ptr(&percpu_mct_tick
, cpu
);
567 if (pcpu_mevt
->evt
.irq
!= -1) {
568 free_irq(pcpu_mevt
->evt
.irq
, pcpu_mevt
);
569 pcpu_mevt
->evt
.irq
= -1;
576 static int __init
mct_init_dt(struct device_node
*np
, unsigned int int_type
)
581 mct_int_type
= int_type
;
583 /* This driver uses only one global timer interrupt */
584 mct_irqs
[MCT_G0_IRQ
] = irq_of_parse_and_map(np
, MCT_G0_IRQ
);
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.
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
);
595 ret
= exynos4_timer_resources(np
, of_iomap(np
, 0));
599 ret
= exynos4_clocksource_init();
603 return exynos4_clockevent_init();
607 static int __init
mct_init_spi(struct device_node
*np
)
609 return mct_init_dt(np
, MCT_INT_SPI
);
612 static int __init
mct_init_ppi(struct device_node
*np
)
614 return mct_init_dt(np
, MCT_INT_PPI
);
616 TIMER_OF_DECLARE(exynos4210
, "samsung,exynos4210-mct", mct_init_spi
);
617 TIMER_OF_DECLARE(exynos4412
, "samsung,exynos4412-mct", mct_init_ppi
);