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/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>
24 #include <linux/of_irq.h>
25 #include <linux/of_address.h>
26 #include <linux/clocksource.h>
27 #include <linux/sched_clock.h>
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)
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)
57 #define TICK_BASE_CNT 1
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
];
85 struct mct_clock_event_device
{
86 struct clock_event_device evt
;
91 static void exynos4_mct_write(unsigned int value
, unsigned long offset
)
93 unsigned long stat_addr
;
97 writel_relaxed(value
, reg_base
+ offset
);
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 */
105 case MCT_L_ICNTB_OFFSET
:
106 mask
= 1 << 1; /* L_ICNTB write status */
108 case MCT_L_TCNTB_OFFSET
:
109 mask
= 1 << 0; /* L_TCNTB write status */
116 case EXYNOS4_MCT_G_TCON
:
117 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
118 mask
= 1 << 16; /* G_TCON write status */
120 case EXYNOS4_MCT_G_COMP0_L
:
121 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
122 mask
= 1 << 0; /* G_COMP0_L write status */
124 case EXYNOS4_MCT_G_COMP0_U
:
125 stat_addr
= EXYNOS4_MCT_G_WSTAT
;
126 mask
= 1 << 1; /* G_COMP0_U write status */
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 */
132 case EXYNOS4_MCT_G_CNT_L
:
133 stat_addr
= EXYNOS4_MCT_G_CNT_WSTAT
;
134 mask
= 1 << 0; /* G_CNT_L write status */
136 case EXYNOS4_MCT_G_CNT_U
:
137 stat_addr
= EXYNOS4_MCT_G_CNT_WSTAT
;
138 mask
= 1 << 1; /* G_CNT_U write status */
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
);
152 panic("MCT hangs after writing %d (offset:0x%lx)\n", value
, offset
);
155 /* Clocksource handling */
156 static void exynos4_mct_frc_start(void)
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
);
166 * exynos4_read_count_64 - Read all 64-bits of the global counter
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.
173 * Returns the number of cycles in the global counter.
175 static u64
exynos4_read_count_64(void)
178 u32 hi2
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_U
);
182 lo
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_L
);
183 hi2
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_U
);
186 return ((cycle_t
)hi
<< 32) | lo
;
190 * exynos4_read_count_32 - Read the lower 32-bits of the global counter
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.
195 * Returns the number of cycles in the global counter (lower 32 bits).
197 static u32 notrace
exynos4_read_count_32(void)
199 return readl_relaxed(reg_base
+ EXYNOS4_MCT_G_CNT_L
);
202 static cycle_t
exynos4_frc_read(struct clocksource
*cs
)
204 return exynos4_read_count_32();
207 static void exynos4_frc_resume(struct clocksource
*cs
)
209 exynos4_mct_frc_start();
212 static struct clocksource mct_frc
= {
215 .read
= exynos4_frc_read
,
216 .mask
= CLOCKSOURCE_MASK(32),
217 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
218 .resume
= exynos4_frc_resume
,
221 static u64 notrace
exynos4_read_sched_clock(void)
223 return exynos4_read_count_32();
226 static struct delay_timer exynos4_delay_timer
;
228 static cycles_t
exynos4_read_current_timer(void)
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();
235 static void __init
exynos4_clocksource_init(void)
237 exynos4_mct_frc_start();
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
);
243 if (clocksource_register_hz(&mct_frc
, clk_rate
))
244 panic("%s: can't register clocksource\n", mct_frc
.name
);
246 sched_clock_register(exynos4_read_sched_clock
, 32, clk_rate
);
249 static void exynos4_mct_comp0_stop(void)
253 tcon
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_TCON
);
254 tcon
&= ~(MCT_G_TCON_COMP0_ENABLE
| MCT_G_TCON_COMP0_AUTO_INC
);
256 exynos4_mct_write(tcon
, EXYNOS4_MCT_G_TCON
);
257 exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB
);
260 static void exynos4_mct_comp0_start(bool periodic
, unsigned long cycles
)
265 tcon
= readl_relaxed(reg_base
+ EXYNOS4_MCT_G_TCON
);
268 tcon
|= MCT_G_TCON_COMP0_AUTO_INC
;
269 exynos4_mct_write(cycles
, EXYNOS4_MCT_G_COMP0_ADD_INCR
);
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
);
276 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB
);
278 tcon
|= MCT_G_TCON_COMP0_ENABLE
;
279 exynos4_mct_write(tcon
, EXYNOS4_MCT_G_TCON
);
282 static int exynos4_comp_set_next_event(unsigned long cycles
,
283 struct clock_event_device
*evt
)
285 exynos4_mct_comp0_start(false, cycles
);
290 static int mct_set_state_shutdown(struct clock_event_device
*evt
)
292 exynos4_mct_comp0_stop();
296 static int mct_set_state_periodic(struct clock_event_device
*evt
)
298 unsigned long cycles_per_jiffy
;
300 cycles_per_jiffy
= (((unsigned long long)NSEC_PER_SEC
/ HZ
* evt
->mult
)
302 exynos4_mct_comp0_stop();
303 exynos4_mct_comp0_start(true, cycles_per_jiffy
);
307 static struct clock_event_device mct_comp_device
= {
309 .features
= CLOCK_EVT_FEAT_PERIODIC
|
310 CLOCK_EVT_FEAT_ONESHOT
,
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 .tick_resume
= mct_set_state_shutdown
,
319 static irqreturn_t
exynos4_mct_comp_isr(int irq
, void *dev_id
)
321 struct clock_event_device
*evt
= dev_id
;
323 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT
);
325 evt
->event_handler(evt
);
330 static struct irqaction mct_comp_event_irq
= {
331 .name
= "mct_comp_irq",
332 .flags
= IRQF_TIMER
| IRQF_IRQPOLL
,
333 .handler
= exynos4_mct_comp_isr
,
334 .dev_id
= &mct_comp_device
,
337 static void exynos4_clockevent_init(void)
339 mct_comp_device
.cpumask
= cpumask_of(0);
340 clockevents_config_and_register(&mct_comp_device
, clk_rate
,
342 setup_irq(mct_irqs
[MCT_G0_IRQ
], &mct_comp_event_irq
);
345 static DEFINE_PER_CPU(struct mct_clock_event_device
, percpu_mct_tick
);
347 /* Clock event handling */
348 static void exynos4_mct_tick_stop(struct mct_clock_event_device
*mevt
)
351 unsigned long mask
= MCT_L_TCON_INT_START
| MCT_L_TCON_TIMER_START
;
352 unsigned long offset
= mevt
->base
+ MCT_L_TCON_OFFSET
;
354 tmp
= readl_relaxed(reg_base
+ offset
);
357 exynos4_mct_write(tmp
, offset
);
361 static void exynos4_mct_tick_start(unsigned long cycles
,
362 struct mct_clock_event_device
*mevt
)
366 exynos4_mct_tick_stop(mevt
);
368 tmp
= (1 << 31) | cycles
; /* MCT_L_UPDATE_ICNTB */
370 /* update interrupt count buffer */
371 exynos4_mct_write(tmp
, mevt
->base
+ MCT_L_ICNTB_OFFSET
);
373 /* enable MCT tick interrupt */
374 exynos4_mct_write(0x1, mevt
->base
+ MCT_L_INT_ENB_OFFSET
);
376 tmp
= readl_relaxed(reg_base
+ mevt
->base
+ MCT_L_TCON_OFFSET
);
377 tmp
|= MCT_L_TCON_INT_START
| MCT_L_TCON_TIMER_START
|
378 MCT_L_TCON_INTERVAL_MODE
;
379 exynos4_mct_write(tmp
, mevt
->base
+ MCT_L_TCON_OFFSET
);
382 static int exynos4_tick_set_next_event(unsigned long cycles
,
383 struct clock_event_device
*evt
)
385 struct mct_clock_event_device
*mevt
;
387 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
388 exynos4_mct_tick_start(cycles
, mevt
);
392 static int set_state_shutdown(struct clock_event_device
*evt
)
394 struct mct_clock_event_device
*mevt
;
396 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
397 exynos4_mct_tick_stop(mevt
);
401 static int set_state_periodic(struct clock_event_device
*evt
)
403 struct mct_clock_event_device
*mevt
;
404 unsigned long cycles_per_jiffy
;
406 mevt
= container_of(evt
, struct mct_clock_event_device
, evt
);
407 cycles_per_jiffy
= (((unsigned long long)NSEC_PER_SEC
/ HZ
* evt
->mult
)
409 exynos4_mct_tick_stop(mevt
);
410 exynos4_mct_tick_start(cycles_per_jiffy
, mevt
);
414 static void exynos4_mct_tick_clear(struct mct_clock_event_device
*mevt
)
417 * This is for supporting oneshot mode.
418 * Mct would generate interrupt periodically
419 * without explicit stopping.
421 if (!clockevent_state_periodic(&mevt
->evt
))
422 exynos4_mct_tick_stop(mevt
);
424 /* Clear the MCT tick interrupt */
425 if (readl_relaxed(reg_base
+ mevt
->base
+ MCT_L_INT_CSTAT_OFFSET
) & 1)
426 exynos4_mct_write(0x1, mevt
->base
+ MCT_L_INT_CSTAT_OFFSET
);
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
;
434 exynos4_mct_tick_clear(mevt
);
436 evt
->event_handler(evt
);
441 static int exynos4_local_timer_setup(struct mct_clock_event_device
*mevt
)
443 struct clock_event_device
*evt
= &mevt
->evt
;
444 unsigned int cpu
= smp_processor_id();
446 mevt
->base
= EXYNOS4_MCT_L_BASE(cpu
);
447 snprintf(mevt
->name
, sizeof(mevt
->name
), "mct_tick%d", cpu
);
449 evt
->name
= mevt
->name
;
450 evt
->cpumask
= cpumask_of(cpu
);
451 evt
->set_next_event
= exynos4_tick_set_next_event
;
452 evt
->set_state_periodic
= set_state_periodic
;
453 evt
->set_state_shutdown
= set_state_shutdown
;
454 evt
->set_state_oneshot
= set_state_shutdown
;
455 evt
->tick_resume
= set_state_shutdown
;
456 evt
->features
= CLOCK_EVT_FEAT_PERIODIC
| CLOCK_EVT_FEAT_ONESHOT
;
459 exynos4_mct_write(TICK_BASE_CNT
, mevt
->base
+ MCT_L_TCNTB_OFFSET
);
461 if (mct_int_type
== MCT_INT_SPI
) {
466 irq_force_affinity(evt
->irq
, cpumask_of(cpu
));
467 enable_irq(evt
->irq
);
469 enable_percpu_irq(mct_irqs
[MCT_L0_IRQ
], 0);
471 clockevents_config_and_register(evt
, clk_rate
/ (TICK_BASE_CNT
+ 1),
477 static void exynos4_local_timer_stop(struct mct_clock_event_device
*mevt
)
479 struct clock_event_device
*evt
= &mevt
->evt
;
481 evt
->set_state_shutdown(evt
);
482 if (mct_int_type
== MCT_INT_SPI
) {
484 disable_irq_nosync(evt
->irq
);
485 exynos4_mct_write(0x1, mevt
->base
+ MCT_L_INT_CSTAT_OFFSET
);
487 disable_percpu_irq(mct_irqs
[MCT_L0_IRQ
]);
491 static int exynos4_mct_cpu_notify(struct notifier_block
*self
,
492 unsigned long action
, void *hcpu
)
494 struct mct_clock_event_device
*mevt
;
497 * Grab cpu pointer in each case to avoid spurious
498 * preemptible warnings
500 switch (action
& ~CPU_TASKS_FROZEN
) {
502 mevt
= this_cpu_ptr(&percpu_mct_tick
);
503 exynos4_local_timer_setup(mevt
);
506 mevt
= this_cpu_ptr(&percpu_mct_tick
);
507 exynos4_local_timer_stop(mevt
);
514 static struct notifier_block exynos4_mct_cpu_nb
= {
515 .notifier_call
= exynos4_mct_cpu_notify
,
518 static void __init
exynos4_timer_resources(struct device_node
*np
, void __iomem
*base
)
521 struct mct_clock_event_device
*mevt
= this_cpu_ptr(&percpu_mct_tick
);
522 struct clk
*mct_clk
, *tick_clk
;
524 tick_clk
= np
? of_clk_get_by_name(np
, "fin_pll") :
525 clk_get(NULL
, "fin_pll");
526 if (IS_ERR(tick_clk
))
527 panic("%s: unable to determine tick clock rate\n", __func__
);
528 clk_rate
= clk_get_rate(tick_clk
);
530 mct_clk
= np
? of_clk_get_by_name(np
, "mct") : clk_get(NULL
, "mct");
532 panic("%s: unable to retrieve mct clock instance\n", __func__
);
533 clk_prepare_enable(mct_clk
);
537 panic("%s: unable to ioremap mct address space\n", __func__
);
539 if (mct_int_type
== MCT_INT_PPI
) {
541 err
= request_percpu_irq(mct_irqs
[MCT_L0_IRQ
],
542 exynos4_mct_tick_isr
, "MCT",
544 WARN(err
, "MCT: can't request IRQ %d (%d)\n",
545 mct_irqs
[MCT_L0_IRQ
], err
);
547 for_each_possible_cpu(cpu
) {
548 int mct_irq
= mct_irqs
[MCT_L0_IRQ
+ cpu
];
549 struct mct_clock_event_device
*pcpu_mevt
=
550 per_cpu_ptr(&percpu_mct_tick
, cpu
);
552 pcpu_mevt
->evt
.irq
= -1;
554 irq_set_status_flags(mct_irq
, IRQ_NOAUTOEN
);
555 if (request_irq(mct_irq
,
556 exynos4_mct_tick_isr
,
557 IRQF_TIMER
| IRQF_NOBALANCING
,
558 pcpu_mevt
->name
, pcpu_mevt
)) {
559 pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
564 pcpu_mevt
->evt
.irq
= mct_irq
;
568 err
= register_cpu_notifier(&exynos4_mct_cpu_nb
);
572 /* Immediately configure the timer on the boot CPU */
573 exynos4_local_timer_setup(mevt
);
577 free_percpu_irq(mct_irqs
[MCT_L0_IRQ
], &percpu_mct_tick
);
580 static void __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.
595 nr_irqs
= of_irq_count(np
);
599 for (i
= MCT_L0_IRQ
; i
< nr_irqs
; i
++)
600 mct_irqs
[i
] = irq_of_parse_and_map(np
, i
);
602 exynos4_timer_resources(np
, of_iomap(np
, 0));
603 exynos4_clocksource_init();
604 exynos4_clockevent_init();
608 static void __init
mct_init_spi(struct device_node
*np
)
610 return mct_init_dt(np
, MCT_INT_SPI
);
613 static void __init
mct_init_ppi(struct device_node
*np
)
615 return mct_init_dt(np
, MCT_INT_PPI
);
617 CLOCKSOURCE_OF_DECLARE(exynos4210
, "samsung,exynos4210-mct", mct_init_spi
);
618 CLOCKSOURCE_OF_DECLARE(exynos4412
, "samsung,exynos4412-mct", mct_init_ppi
);