Commit | Line | Data |
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022c03a2 MZ |
1 | /* |
2 | * linux/arch/arm/kernel/arch_timer.c | |
3 | * | |
4 | * Copyright (C) 2011 ARM Ltd. | |
5 | * All Rights Reserved | |
6 | * | |
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. | |
10 | */ | |
11 | #include <linux/init.h> | |
8a4da6e3 | 12 | #include <linux/types.h> |
fe7dc720 | 13 | #include <linux/errno.h> |
022c03a2 | 14 | |
56942fec | 15 | #include <asm/delay.h> |
3f61c80e | 16 | #include <asm/sched_clock.h> |
022c03a2 | 17 | |
8a4da6e3 | 18 | #include <clocksource/arm_arch_timer.h> |
f48b5f12 | 19 | |
8a4da6e3 | 20 | static unsigned long arch_timer_read_counter_long(void) |
022c03a2 | 21 | { |
b8e24343 | 22 | return arch_timer_read_counter(); |
022c03a2 MZ |
23 | } |
24 | ||
023796b9 RH |
25 | static u32 sched_clock_mult __read_mostly; |
26 | ||
27 | static unsigned long long notrace arch_timer_sched_clock(void) | |
923df96b | 28 | { |
023796b9 | 29 | return arch_timer_read_counter() * sched_clock_mult; |
923df96b WD |
30 | } |
31 | ||
8a4da6e3 | 32 | static struct delay_timer arch_delay_timer; |
273d16ad | 33 | |
8a4da6e3 | 34 | static void __init arch_timer_delay_timer_register(void) |
022c03a2 | 35 | { |
56942fec | 36 | /* Use the architected timer for the delay loop. */ |
8a4da6e3 MR |
37 | arch_delay_timer.read_current_timer = arch_timer_read_counter_long; |
38 | arch_delay_timer.freq = arch_timer_get_rate(); | |
56942fec | 39 | register_current_timer_delay(&arch_delay_timer); |
022c03a2 | 40 | } |
3f61c80e | 41 | |
0583fe47 | 42 | int __init arch_timer_arch_init(void) |
3f61c80e | 43 | { |
023796b9 RH |
44 | u32 arch_timer_rate = arch_timer_get_rate(); |
45 | ||
46 | if (arch_timer_rate == 0) | |
8a4da6e3 | 47 | return -ENXIO; |
3f61c80e | 48 | |
0583fe47 RH |
49 | arch_timer_delay_timer_register(); |
50 | ||
023796b9 RH |
51 | /* Cache the sched_clock multiplier to save a divide in the hot path. */ |
52 | sched_clock_mult = NSEC_PER_SEC / arch_timer_rate; | |
53 | sched_clock_func = arch_timer_sched_clock; | |
54 | pr_info("sched_clock: ARM arch timer >56 bits at %ukHz, resolution %uns\n", | |
55 | arch_timer_rate / 1000, sched_clock_mult); | |
56 | ||
3f61c80e MZ |
57 | return 0; |
58 | } |