1 /* linux/arch/arm/mach-exynos4/mct.c
3 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
4 * http://www.samsung.com
6 * EXYNOS4 MCT(Multi-Core Timer) support
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.
13 #include <linux/interrupt.h>
14 #include <linux/irq.h>
15 #include <linux/err.h>
16 #include <linux/clk.h>
17 #include <linux/clockchips.h>
18 #include <linux/cpu.h>
19 #include <linux/delay.h>
20 #include <linux/percpu.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_address.h>
24 #include <linux/clocksource.h>
25 #include <linux/sched_clock.h>
27 #define EXYNOS4_MCTREG(x) (x)
28 #define EXYNOS4_MCT_G_CNT_L EXYNOS4_MCTREG(0x100)
29 #define EXYNOS4_MCT_G_CNT_U EXYNOS4_MCTREG(0x104)
30 #define EXYNOS4_MCT_G_CNT_WSTAT EXYNOS4_MCTREG(0x110)
31 #define EXYNOS4_MCT_G_COMP0_L EXYNOS4_MCTREG(0x200)
32 #define EXYNOS4_MCT_G_COMP0_U EXYNOS4_MCTREG(0x204)
33 #define EXYNOS4_MCT_G_COMP0_ADD_INCR EXYNOS4_MCTREG(0x208)
34 #define EXYNOS4_MCT_G_TCON EXYNOS4_MCTREG(0x240)
35 #define EXYNOS4_MCT_G_INT_CSTAT EXYNOS4_MCTREG(0x244)
36 #define EXYNOS4_MCT_G_INT_ENB EXYNOS4_MCTREG(0x248)
37 #define EXYNOS4_MCT_G_WSTAT EXYNOS4_MCTREG(0x24C)
38 #define _EXYNOS4_MCT_L_BASE EXYNOS4_MCTREG(0x300)
39 #define EXYNOS4_MCT_L_BASE(x) (_EXYNOS4_MCT_L_BASE + (0x100 * x))
40 #define EXYNOS4_MCT_L_MASK (0xffffff00)
42 #define MCT_L_TCNTB_OFFSET (0x00)
43 #define MCT_L_ICNTB_OFFSET (0x08)
44 #define MCT_L_TCON_OFFSET (0x20)
45 #define MCT_L_INT_CSTAT_OFFSET (0x30)
46 #define MCT_L_INT_ENB_OFFSET (0x34)
47 #define MCT_L_WSTAT_OFFSET (0x40)
48 #define MCT_G_TCON_START (1 << 8)
49 #define MCT_G_TCON_COMP0_AUTO_INC (1 << 1)
50 #define MCT_G_TCON_COMP0_ENABLE (1 << 0)
51 #define MCT_L_TCON_INTERVAL_MODE (1 << 2)
52 #define MCT_L_TCON_INT_START (1 << 1)
53 #define MCT_L_TCON_TIMER_START (1 << 0)
55 #define TICK_BASE_CNT 1
78 static void __iomem
*reg_base
;
79 static unsigned long clk_rate
;
80 static unsigned int mct_int_type
;
81 static int mct_irqs
[MCT_NR_IRQS
];
83 struct mct_clock_event_device
{
84 struct clock_event_device evt
;
89 static void exynos4_mct_write(unsigned int value
, unsigned long offset
)
91 unsigned long stat_addr
;
95 writel_relaxed(value
, reg_base
+ offset
);
97 if (likely(offset
>= EXYNOS4_MCT_L_BASE(0))) {
98 stat_addr
= (offset
& EXYNOS4_MCT_L_MASK
) + MCT_L_WSTAT_OFFSET
;
99 switch (offset
& ~EXYNOS4_MCT_L_MASK
) {
100 case MCT_L_TCON_OFFSET
:
101 mask
= 1 << 3; /* L_TCON write status */
103 case MCT_L_ICNTB_OFFSET
:
104 mask
= 1 << 1; /* L_ICNTB write status */
106 case MCT_L_TCNTB_OFFSET
:
107 mask
= 1 << 0; /* L_TCNTB write status */
114 case EXYNOS4_MCT_G_TCON
:
115 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
116 mask
= 1 << 16; /* G_TCON write status */
118 case EXYNOS4_MCT_G_COMP0_L
:
119 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
120 mask
= 1 << 0; /* G_COMP0_L write status */
122 case EXYNOS4_MCT_G_COMP0_U
:
123 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
124 mask
= 1 << 1; /* G_COMP0_U write status */
126 case EXYNOS4_MCT_G_COMP0_ADD_INCR
:
127 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
128 mask
= 1 << 2; /* G_COMP0_ADD_INCR w status */
130 case EXYNOS4_MCT_G_CNT_L
:
131 stat_addr
= EXYNOS4_MCT_G_CNT_WSTAT
;
132 mask
= 1 << 0; /* G_CNT_L write status */
134 case EXYNOS4_MCT_G_CNT_U
:
135 stat_addr
= EXYNOS4_MCT_G_CNT_WSTAT
;
136 mask
= 1 << 1; /* G_CNT_U write status */
143 /* Wait maximum 1 ms until written values are applied */
144 for (i
= 0; i
< loops_per_jiffy
/ 1000 * HZ
; i
++)
145 if (readl_relaxed(reg_base
+ stat_addr
) & mask
) {
146 writel_relaxed(mask
, reg_base
+ stat_addr
);
150 panic("MCT hangs after writing %d (offset:0x%lx)\n", value
, offset
);
153 /* Clocksource handling */
154 static void exynos4_mct_frc_start(void)
158 reg
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_TCON
);
159 reg
|= MCT_G_TCON_START
;
160 exynos4_mct_write(reg
, EXYNOS4_MCT_G_TCON
);
164 * exynos4_read_count_64 - Read all 64-bits of the global counter
166 * This will read all 64-bits of the global counter taking care to make sure
167 * that the upper and lower half match. Note that reading the MCT can be quite
168 * slow (hundreds of nanoseconds) so you should use the 32-bit (lower half
169 * only) version when possible.
171 * Returns the number of cycles in the global counter.
173 static u64
exynos4_read_count_64(void)
176 u32 hi2
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_U
);
180 lo
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_L
);
181 hi2
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_U
);
184 return ((u64
)hi
<< 32) | lo
;
188 * exynos4_read_count_32 - Read the lower 32-bits of the global counter
190 * This will read just the lower 32-bits of the global counter. This is marked
191 * as notrace so it can be used by the scheduler clock.
193 * Returns the number of cycles in the global counter (lower 32 bits).
195 static u32 notrace
exynos4_read_count_32(void)
197 return readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_L
);
200 static u64
exynos4_frc_read(struct clocksource
*cs
)
202 return exynos4_read_count_32();
205 static void exynos4_frc_resume(struct clocksource
*cs
)
207 exynos4_mct_frc_start();
210 static struct clocksource mct_frc
= {
213 .read
= exynos4_frc_read
,
214 .mask
= CLOCKSOURCE_MASK(32),
215 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
216 .resume
= exynos4_frc_resume
,
219 static u64 notrace
exynos4_read_sched_clock(void)
221 return exynos4_read_count_32();
224 #if defined(CONFIG_ARM)
225 static struct delay_timer exynos4_delay_timer
;
227 static cycles_t
exynos4_read_current_timer(void)
229 BUILD_BUG_ON_MSG(sizeof(cycles_t
) != sizeof(u32
),
230 "cycles_t needs to move to 32-bit for ARM64 usage");
231 return exynos4_read_count_32();
235 static int __init
exynos4_clocksource_init(void)
237 exynos4_mct_frc_start();
239 #if defined(CONFIG_ARM)
240 exynos4_delay_timer
.read_current_timer
= &exynos4_read_current_timer
;
241 exynos4_delay_timer
.freq
= clk_rate
;
242 register_current_timer_delay(&exynos4_delay_timer
);
245 if (clocksource_register_hz(&mct_frc
, clk_rate
))
246 panic("%s: can't register clocksource\n", mct_frc
.name
);
248 sched_clock_register(exynos4_read_sched_clock
, 32, clk_rate
);
253 static void exynos4_mct_comp0_stop(void)
257 tcon
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_TCON
);
258 tcon
&= ~(MCT_G_TCON_COMP0_ENABLE
| MCT_G_TCON_COMP0_AUTO_INC
);
260 exynos4_mct_write(tcon
, EXYNOS4_MCT_G_TCON
);
261 exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB
);
264 static void exynos4_mct_comp0_start(bool periodic
, unsigned long cycles
)
269 tcon
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_TCON
);
272 tcon
|= MCT_G_TCON_COMP0_AUTO_INC
;
273 exynos4_mct_write(cycles
, EXYNOS4_MCT_G_COMP0_ADD_INCR
);
276 comp_cycle
= exynos4_read_count_64() + cycles
;
277 exynos4_mct_write((u32
)comp_cycle
, EXYNOS4_MCT_G_COMP0_L
);
278 exynos4_mct_write((u32
)(comp_cycle
>> 32), EXYNOS4_MCT_G_COMP0_U
);
280 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB
);
282 tcon
|= MCT_G_TCON_COMP0_ENABLE
;
283 exynos4_mct_write(tcon
, EXYNOS4_MCT_G_TCON
);
286 static int exynos4_comp_set_next_event(unsigned long cycles
,
287 struct clock_event_device
*evt
)
289 exynos4_mct_comp0_start(false, cycles
);
294 static int mct_set_state_shutdown(struct clock_event_device
*evt
)
296 exynos4_mct_comp0_stop();
300 static int mct_set_state_periodic(struct clock_event_device
*evt
)
302 unsigned long cycles_per_jiffy
;
304 cycles_per_jiffy
= (((unsigned long long)NSEC_PER_SEC
/ HZ
* evt
->mult
)
306 exynos4_mct_comp0_stop();
307 exynos4_mct_comp0_start(true, cycles_per_jiffy
);
311 static struct clock_event_device mct_comp_device
= {
313 .features
= CLOCK_EVT_FEAT_PERIODIC
|
314 CLOCK_EVT_FEAT_ONESHOT
,
316 .set_next_event
= exynos4_comp_set_next_event
,
317 .set_state_periodic
= mct_set_state_periodic
,
318 .set_state_shutdown
= mct_set_state_shutdown
,
319 .set_state_oneshot
= mct_set_state_shutdown
,
320 .set_state_oneshot_stopped
= mct_set_state_shutdown
,
321 .tick_resume
= mct_set_state_shutdown
,
324 static irqreturn_t
exynos4_mct_comp_isr(int irq
, void *dev_id
)
326 struct clock_event_device
*evt
= dev_id
;
328 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT
);
330 evt
->event_handler(evt
);
335 static struct irqaction mct_comp_event_irq
= {
336 .name
= "mct_comp_irq",
337 .flags
= IRQF_TIMER
| IRQF_IRQPOLL
,
338 .handler
= exynos4_mct_comp_isr
,
339 .dev_id
= &mct_comp_device
,
342 static int exynos4_clockevent_init(void)
344 mct_comp_device
.cpumask
= cpumask_of(0);
345 clockevents_config_and_register(&mct_comp_device
, clk_rate
,
347 setup_irq(mct_irqs
[MCT_G0_IRQ
], &mct_comp_event_irq
);
352 static DEFINE_PER_CPU(struct mct_clock_event_device
, percpu_mct_tick
);
354 /* Clock event handling */
355 static void exynos4_mct_tick_stop(struct mct_clock_event_device
*mevt
)
358 unsigned long mask
= MCT_L_TCON_INT_START
| MCT_L_TCON_TIMER_START
;
359 unsigned long offset
= mevt
->base
+ MCT_L_TCON_OFFSET
;
361 tmp
= readl_relaxed(reg_base
+ offset
);
364 exynos4_mct_write(tmp
, offset
);
368 static void exynos4_mct_tick_start(unsigned long cycles
,
369 struct mct_clock_event_device
*mevt
)
373 exynos4_mct_tick_stop(mevt
);
375 tmp
= (1 << 31) | cycles
; /* MCT_L_UPDATE_ICNTB */
377 /* update interrupt count buffer */
378 exynos4_mct_write(tmp
, mevt
->base
+ MCT_L_ICNTB_OFFSET
);
380 /* enable MCT tick interrupt */
381 exynos4_mct_write(0x1, mevt
->base
+ MCT_L_INT_ENB_OFFSET
);
383 tmp
= readl_relaxed(reg_base
+ mevt
->base
+ MCT_L_TCON_OFFSET
);
384 tmp
|= MCT_L_TCON_INT_START
| MCT_L_TCON_TIMER_START
|
385 MCT_L_TCON_INTERVAL_MODE
;
386 exynos4_mct_write(tmp
, mevt
->base
+ MCT_L_TCON_OFFSET
);
389 static void exynos4_mct_tick_clear(struct mct_clock_event_device
*mevt
)
391 /* Clear the MCT tick interrupt */
392 if (readl_relaxed(reg_base
+ mevt
->base
+ MCT_L_INT_CSTAT_OFFSET
) & 1)
393 exynos4_mct_write(0x1, mevt
->base
+ MCT_L_INT_CSTAT_OFFSET
);
396 static int exynos4_tick_set_next_event(unsigned long cycles
,
397 struct clock_event_device
*evt
)
399 struct mct_clock_event_device
*mevt
;
401 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
402 exynos4_mct_tick_start(cycles
, mevt
);
406 static int set_state_shutdown(struct clock_event_device
*evt
)
408 struct mct_clock_event_device
*mevt
;
410 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
411 exynos4_mct_tick_stop(mevt
);
412 exynos4_mct_tick_clear(mevt
);
416 static int set_state_periodic(struct clock_event_device
*evt
)
418 struct mct_clock_event_device
*mevt
;
419 unsigned long cycles_per_jiffy
;
421 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
422 cycles_per_jiffy
= (((unsigned long long)NSEC_PER_SEC
/ HZ
* evt
->mult
)
424 exynos4_mct_tick_stop(mevt
);
425 exynos4_mct_tick_start(cycles_per_jiffy
, mevt
);
429 static irqreturn_t
exynos4_mct_tick_isr(int irq
, void *dev_id
)
431 struct mct_clock_event_device
*mevt
= dev_id
;
432 struct clock_event_device
*evt
= &mevt
->evt
;
435 * This is for supporting oneshot mode.
436 * Mct would generate interrupt periodically
437 * without explicit stopping.
439 if (!clockevent_state_periodic(&mevt
->evt
))
440 exynos4_mct_tick_stop(mevt
);
442 exynos4_mct_tick_clear(mevt
);
444 evt
->event_handler(evt
);
449 static int exynos4_mct_starting_cpu(unsigned int cpu
)
451 struct mct_clock_event_device
*mevt
=
452 per_cpu_ptr(&percpu_mct_tick
, cpu
);
453 struct clock_event_device
*evt
= &mevt
->evt
;
455 mevt
->base
= EXYNOS4_MCT_L_BASE(cpu
);
456 snprintf(mevt
->name
, sizeof(mevt
->name
), "mct_tick%d", cpu
);
458 evt
->name
= mevt
->name
;
459 evt
->cpumask
= cpumask_of(cpu
);
460 evt
->set_next_event
= exynos4_tick_set_next_event
;
461 evt
->set_state_periodic
= set_state_periodic
;
462 evt
->set_state_shutdown
= set_state_shutdown
;
463 evt
->set_state_oneshot
= set_state_shutdown
;
464 evt
->set_state_oneshot_stopped
= set_state_shutdown
;
465 evt
->tick_resume
= set_state_shutdown
;
466 evt
->features
= CLOCK_EVT_FEAT_PERIODIC
| CLOCK_EVT_FEAT_ONESHOT
;
469 exynos4_mct_write(TICK_BASE_CNT
, mevt
->base
+ MCT_L_TCNTB_OFFSET
);
471 if (mct_int_type
== MCT_INT_SPI
) {
476 irq_force_affinity(evt
->irq
, cpumask_of(cpu
));
477 enable_irq(evt
->irq
);
479 enable_percpu_irq(mct_irqs
[MCT_L0_IRQ
], 0);
481 clockevents_config_and_register(evt
, clk_rate
/ (TICK_BASE_CNT
+ 1),
487 static int exynos4_mct_dying_cpu(unsigned int cpu
)
489 struct mct_clock_event_device
*mevt
=
490 per_cpu_ptr(&percpu_mct_tick
, cpu
);
491 struct clock_event_device
*evt
= &mevt
->evt
;
493 evt
->set_state_shutdown(evt
);
494 if (mct_int_type
== MCT_INT_SPI
) {
496 disable_irq_nosync(evt
->irq
);
497 exynos4_mct_write(0x1, mevt
->base
+ MCT_L_INT_CSTAT_OFFSET
);
499 disable_percpu_irq(mct_irqs
[MCT_L0_IRQ
]);
504 static int __init
exynos4_timer_resources(struct device_node
*np
, void __iomem
*base
)
507 struct clk
*mct_clk
, *tick_clk
;
509 tick_clk
= of_clk_get_by_name(np
, "fin_pll");
510 if (IS_ERR(tick_clk
))
511 panic("%s: unable to determine tick clock rate\n", __func__
);
512 clk_rate
= clk_get_rate(tick_clk
);
514 mct_clk
= of_clk_get_by_name(np
, "mct");
516 panic("%s: unable to retrieve mct clock instance\n", __func__
);
517 clk_prepare_enable(mct_clk
);
521 panic("%s: unable to ioremap mct address space\n", __func__
);
523 if (mct_int_type
== MCT_INT_PPI
) {
525 err
= request_percpu_irq(mct_irqs
[MCT_L0_IRQ
],
526 exynos4_mct_tick_isr
, "MCT",
528 WARN(err
, "MCT: can't request IRQ %d (%d)\n",
529 mct_irqs
[MCT_L0_IRQ
], err
);
531 for_each_possible_cpu(cpu
) {
532 int mct_irq
= mct_irqs
[MCT_L0_IRQ
+ cpu
];
533 struct mct_clock_event_device
*pcpu_mevt
=
534 per_cpu_ptr(&percpu_mct_tick
, cpu
);
536 pcpu_mevt
->evt
.irq
= -1;
538 irq_set_status_flags(mct_irq
, IRQ_NOAUTOEN
);
539 if (request_irq(mct_irq
,
540 exynos4_mct_tick_isr
,
541 IRQF_TIMER
| IRQF_NOBALANCING
,
542 pcpu_mevt
->name
, pcpu_mevt
)) {
543 pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
548 pcpu_mevt
->evt
.irq
= mct_irq
;
552 /* Install hotplug callbacks which configure the timer on this CPU */
553 err
= cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING
,
554 "clockevents/exynos4/mct_timer:starting",
555 exynos4_mct_starting_cpu
,
556 exynos4_mct_dying_cpu
);
563 if (mct_int_type
== MCT_INT_PPI
) {
564 free_percpu_irq(mct_irqs
[MCT_L0_IRQ
], &percpu_mct_tick
);
566 for_each_possible_cpu(cpu
) {
567 struct mct_clock_event_device
*pcpu_mevt
=
568 per_cpu_ptr(&percpu_mct_tick
, cpu
);
570 if (pcpu_mevt
->evt
.irq
!= -1) {
571 free_irq(pcpu_mevt
->evt
.irq
, pcpu_mevt
);
572 pcpu_mevt
->evt
.irq
= -1;
579 static int __init
mct_init_dt(struct device_node
*np
, unsigned int int_type
)
584 mct_int_type
= int_type
;
586 /* This driver uses only one global timer interrupt */
587 mct_irqs
[MCT_G0_IRQ
] = irq_of_parse_and_map(np
, MCT_G0_IRQ
);
590 * Find out the number of local irqs specified. The local
591 * timer irqs are specified after the four global timer
592 * irqs are specified.
594 nr_irqs
= of_irq_count(np
);
595 for (i
= MCT_L0_IRQ
; i
< nr_irqs
; i
++)
596 mct_irqs
[i
] = irq_of_parse_and_map(np
, i
);
598 ret
= exynos4_timer_resources(np
, of_iomap(np
, 0));
602 ret
= exynos4_clocksource_init();
606 return exynos4_clockevent_init();
610 static int __init
mct_init_spi(struct device_node
*np
)
612 return mct_init_dt(np
, MCT_INT_SPI
);
615 static int __init
mct_init_ppi(struct device_node
*np
)
617 return mct_init_dt(np
, MCT_INT_PPI
);
619 TIMER_OF_DECLARE(exynos4210
, "samsung,exynos4210-mct", mct_init_spi
);
620 TIMER_OF_DECLARE(exynos4412
, "samsung,exynos4412-mct", mct_init_ppi
);