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5a0015d6 CZ |
1 | /* |
2 | * arch/xtensa/kernel/time.c | |
3 | * | |
4 | * Timer and clock support. | |
5 | * | |
6 | * This file is subject to the terms and conditions of the GNU General Public | |
7 | * License. See the file "COPYING" in the main directory of this archive | |
8 | * for more details. | |
9 | * | |
10 | * Copyright (C) 2005 Tensilica Inc. | |
11 | * | |
12 | * Chris Zankel <chris@zankel.net> | |
13 | */ | |
14 | ||
5a0015d6 | 15 | #include <linux/errno.h> |
d43c36dc | 16 | #include <linux/sched.h> |
5a0015d6 | 17 | #include <linux/time.h> |
fcc8f0f8 | 18 | #include <linux/clocksource.h> |
5a0015d6 CZ |
19 | #include <linux/interrupt.h> |
20 | #include <linux/module.h> | |
21 | #include <linux/init.h> | |
22 | #include <linux/irq.h> | |
23 | #include <linux/profile.h> | |
24 | #include <linux/delay.h> | |
2206d5dd | 25 | #include <linux/irqdomain.h> |
5a0015d6 CZ |
26 | |
27 | #include <asm/timex.h> | |
28 | #include <asm/platform.h> | |
29 | ||
5a0015d6 | 30 | #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT |
e504c4b6 | 31 | unsigned long ccount_freq; /* ccount Hz */ |
5a0015d6 CZ |
32 | #endif |
33 | ||
09378d7c | 34 | static cycle_t ccount_read(struct clocksource *cs) |
fcc8f0f8 JW |
35 | { |
36 | return (cycle_t)get_ccount(); | |
37 | } | |
38 | ||
39 | static struct clocksource ccount_clocksource = { | |
40 | .name = "ccount", | |
41 | .rating = 200, | |
42 | .read = ccount_read, | |
43 | .mask = CLOCKSOURCE_MASK(32), | |
fcc8f0f8 JW |
44 | }; |
45 | ||
fd43fe19 | 46 | static irqreturn_t timer_interrupt(int irq, void *dev_id); |
5a0015d6 CZ |
47 | static struct irqaction timer_irqaction = { |
48 | .handler = timer_interrupt, | |
85ac3ab2 | 49 | .flags = IRQF_DISABLED, |
5a0015d6 CZ |
50 | .name = "timer", |
51 | }; | |
52 | ||
53 | void __init time_init(void) | |
54 | { | |
2206d5dd | 55 | unsigned int irq; |
288a60cf | 56 | #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT |
5a0015d6 CZ |
57 | printk("Calibrating CPU frequency "); |
58 | platform_calibrate_ccount(); | |
e504c4b6 BS |
59 | printk("%d.%02d MHz\n", (int)ccount_freq/1000000, |
60 | (int)(ccount_freq/10000)%100); | |
5a0015d6 | 61 | #endif |
a139723b | 62 | clocksource_register_hz(&ccount_clocksource, CCOUNT_PER_JIFFY * HZ); |
5a0015d6 CZ |
63 | |
64 | /* Initialize the linux timer interrupt. */ | |
65 | ||
2206d5dd MF |
66 | irq = irq_create_mapping(NULL, LINUX_TIMER_INT); |
67 | setup_irq(irq, &timer_irqaction); | |
5a0015d6 CZ |
68 | set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY); |
69 | } | |
70 | ||
5a0015d6 CZ |
71 | /* |
72 | * The timer interrupt is called HZ times per second. | |
73 | */ | |
74 | ||
fd43fe19 | 75 | irqreturn_t timer_interrupt (int irq, void *dev_id) |
5a0015d6 CZ |
76 | { |
77 | ||
78 | unsigned long next; | |
79 | ||
80 | next = get_linux_timer(); | |
81 | ||
82 | again: | |
83 | while ((signed long)(get_ccount() - next) > 0) { | |
84 | ||
fd43fe19 | 85 | profile_tick(CPU_PROFILING); |
5a0015d6 | 86 | #ifndef CONFIG_SMP |
fd43fe19 | 87 | update_process_times(user_mode(get_irq_regs())); |
5a0015d6 CZ |
88 | #endif |
89 | ||
d12b0e24 | 90 | xtime_update(1); /* Linux handler in kernel/time/timekeeping */ |
2b8aea74 CZ |
91 | |
92 | /* Note that writing CCOMPARE clears the interrupt. */ | |
93 | ||
5a0015d6 | 94 | next += CCOUNT_PER_JIFFY; |
2b8aea74 | 95 | set_linux_timer(next); |
5a0015d6 CZ |
96 | } |
97 | ||
2b8aea74 | 98 | /* Allow platform to do something useful (Wdog). */ |
5a0015d6 | 99 | |
2b8aea74 | 100 | platform_heartbeat(); |
5a0015d6 CZ |
101 | |
102 | /* Make sure we didn't miss any tick... */ | |
103 | ||
104 | if ((signed long)(get_ccount() - next) > 0) | |
105 | goto again; | |
106 | ||
5a0015d6 CZ |
107 | return IRQ_HANDLED; |
108 | } | |
109 | ||
110 | #ifndef CONFIG_GENERIC_CALIBRATE_DELAY | |
6c81c32f | 111 | void __cpuinit calibrate_delay(void) |
5a0015d6 CZ |
112 | { |
113 | loops_per_jiffy = CCOUNT_PER_JIFFY; | |
114 | printk("Calibrating delay loop (skipped)... " | |
115 | "%lu.%02lu BogoMIPS preset\n", | |
116 | loops_per_jiffy/(1000000/HZ), | |
117 | (loops_per_jiffy/(10000/HZ)) % 100); | |
118 | } | |
119 | #endif |