2 * linux/arch/arm/kernel/time.c
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
5 * Modifications for ARM (C) 1994-2001 Russell King
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This file contains the ARM-specific time handling details:
12 * reading the RTC at bootup, etc...
14 #include <linux/export.h>
15 #include <linux/kernel.h>
16 #include <linux/interrupt.h>
17 #include <linux/time.h>
18 #include <linux/init.h>
19 #include <linux/sched.h>
20 #include <linux/smp.h>
21 #include <linux/timex.h>
22 #include <linux/errno.h>
23 #include <linux/profile.h>
24 #include <linux/timer.h>
25 #include <linux/clocksource.h>
26 #include <linux/irq.h>
27 #include <linux/sched_clock.h>
29 #include <asm/thread_info.h>
30 #include <asm/stacktrace.h>
31 #include <asm/mach/arch.h>
32 #include <asm/mach/time.h>
34 #if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || \
35 defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE)
36 /* this needs a better home */
37 DEFINE_SPINLOCK(rtc_lock
);
38 EXPORT_SYMBOL(rtc_lock
);
39 #endif /* pc-style 'CMOS' RTC support */
41 /* change this if you have some constant time drift */
42 #define USECS_PER_JIFFY (1000000/HZ)
45 unsigned long profile_pc(struct pt_regs
*regs
)
47 struct stackframe frame
;
49 if (!in_lock_functions(regs
->ARM_pc
))
52 frame
.fp
= regs
->ARM_fp
;
53 frame
.sp
= regs
->ARM_sp
;
54 frame
.lr
= regs
->ARM_lr
;
55 frame
.pc
= regs
->ARM_pc
;
57 int ret
= unwind_frame(&frame
);
60 } while (in_lock_functions(frame
.pc
));
64 EXPORT_SYMBOL(profile_pc
);
67 #ifndef CONFIG_GENERIC_CLOCKEVENTS
69 * Kernel system timer support.
73 profile_tick(CPU_PROFILING
);
76 update_process_times(user_mode(get_irq_regs()));
81 static void dummy_clock_access(struct timespec
*ts
)
87 static clock_access_fn __read_persistent_clock
= dummy_clock_access
;
88 static clock_access_fn __read_boot_clock
= dummy_clock_access
;;
90 void read_persistent_clock(struct timespec
*ts
)
92 __read_persistent_clock(ts
);
95 void read_boot_clock(struct timespec
*ts
)
97 __read_boot_clock(ts
);
100 int __init
register_persistent_clock(clock_access_fn read_boot
,
101 clock_access_fn read_persistent
)
103 /* Only allow the clockaccess functions to be registered once */
104 if (__read_persistent_clock
== dummy_clock_access
&&
105 __read_boot_clock
== dummy_clock_access
) {
107 __read_boot_clock
= read_boot
;
109 __read_persistent_clock
= read_persistent
;
117 void __init
time_init(void)
119 if (machine_desc
->init_time
)
120 machine_desc
->init_time();
122 clocksource_of_init();