2 * linux/arch/arm/mach-sa1100/time.c
4 * Copyright (C) 1998 Deborah Wallach.
5 * Twiddles (C) 1999 Hugo Fiennes <hugo@empeg.com>
7 * 2000/03/29 (C) Nicolas Pitre <nico@fluxnic.net>
8 * Rewritten: big cleanup, much simpler, better HZ accuracy.
11 #include <linux/init.h>
12 #include <linux/errno.h>
13 #include <linux/interrupt.h>
14 #include <linux/irq.h>
15 #include <linux/timex.h>
16 #include <linux/clockchips.h>
18 #include <asm/mach/time.h>
19 #include <asm/sched_clock.h>
20 #include <mach/hardware.h>
21 #include <mach/irqs.h>
23 static u32 notrace
sa1100_read_sched_clock(void)
28 #define MIN_OSCR_DELTA 2
30 static irqreturn_t
sa1100_ost0_interrupt(int irq
, void *dev_id
)
32 struct clock_event_device
*c
= dev_id
;
34 /* Disarm the compare/match, signal the event. */
43 sa1100_osmr0_set_next_event(unsigned long delta
, struct clock_event_device
*c
)
45 unsigned long next
, oscr
;
52 return (signed)(next
- oscr
) <= MIN_OSCR_DELTA
? -ETIME
: 0;
56 sa1100_osmr0_set_mode(enum clock_event_mode mode
, struct clock_event_device
*c
)
59 case CLOCK_EVT_MODE_ONESHOT
:
60 case CLOCK_EVT_MODE_UNUSED
:
61 case CLOCK_EVT_MODE_SHUTDOWN
:
66 case CLOCK_EVT_MODE_RESUME
:
67 case CLOCK_EVT_MODE_PERIODIC
:
72 static struct clock_event_device ckevt_sa1100_osmr0
= {
74 .features
= CLOCK_EVT_FEAT_ONESHOT
,
76 .set_next_event
= sa1100_osmr0_set_next_event
,
77 .set_mode
= sa1100_osmr0_set_mode
,
80 static struct irqaction sa1100_timer_irq
= {
82 .flags
= IRQF_DISABLED
| IRQF_TIMER
| IRQF_IRQPOLL
,
83 .handler
= sa1100_ost0_interrupt
,
84 .dev_id
= &ckevt_sa1100_osmr0
,
87 static void __init
sa1100_timer_init(void)
90 OSSR
= OSSR_M0
| OSSR_M1
| OSSR_M2
| OSSR_M3
;
92 setup_sched_clock(sa1100_read_sched_clock
, 32, 3686400);
94 clockevents_calc_mult_shift(&ckevt_sa1100_osmr0
, 3686400, 4);
95 ckevt_sa1100_osmr0
.max_delta_ns
=
96 clockevent_delta2ns(0x7fffffff, &ckevt_sa1100_osmr0
);
97 ckevt_sa1100_osmr0
.min_delta_ns
=
98 clockevent_delta2ns(MIN_OSCR_DELTA
* 2, &ckevt_sa1100_osmr0
) + 1;
99 ckevt_sa1100_osmr0
.cpumask
= cpumask_of(0);
101 setup_irq(IRQ_OST0
, &sa1100_timer_irq
);
103 clocksource_mmio_init(&OSCR
, "oscr", CLOCK_TICK_RATE
, 200, 32,
104 clocksource_mmio_readl_up
);
105 clockevents_register_device(&ckevt_sa1100_osmr0
);
109 unsigned long osmr
[4], oier
;
111 static void sa1100_timer_suspend(void)
120 static void sa1100_timer_resume(void)
130 * OSMR0 is the system timer: make sure OSCR is sufficiently behind
132 OSCR
= OSMR0
- LATCH
;
135 #define sa1100_timer_suspend NULL
136 #define sa1100_timer_resume NULL
139 struct sys_timer sa1100_timer
= {
140 .init
= sa1100_timer_init
,
141 .suspend
= sa1100_timer_suspend
,
142 .resume
= sa1100_timer_resume
,