Add linux-next specific files for 20110831
[linux-2.6/next.git] / arch / mips / kernel / time.c
blob99d73b72b00b763e537425d6d63d8bdd7c8ccdbb
1 /*
2 * Copyright 2001 MontaVista Software Inc.
3 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
4 * Copyright (c) 2003, 2004 Maciej W. Rozycki
6 * Common time service routines for MIPS machines.
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
13 #include <linux/bug.h>
14 #include <linux/clockchips.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/sched.h>
19 #include <linux/param.h>
20 #include <linux/time.h>
21 #include <linux/timex.h>
22 #include <linux/smp.h>
23 #include <linux/spinlock.h>
24 #include <linux/export.h>
26 #include <asm/cpu-features.h>
27 #include <asm/div64.h>
28 #include <asm/smtc_ipi.h>
29 #include <asm/time.h>
32 * forward reference
34 DEFINE_SPINLOCK(rtc_lock);
35 EXPORT_SYMBOL(rtc_lock);
37 int __weak rtc_mips_set_time(unsigned long sec)
39 return 0;
42 int __weak rtc_mips_set_mmss(unsigned long nowtime)
44 return rtc_mips_set_time(nowtime);
47 int update_persistent_clock(struct timespec now)
49 return rtc_mips_set_mmss(now.tv_sec);
52 static int null_perf_irq(void)
54 return 0;
57 int (*perf_irq)(void) = null_perf_irq;
59 EXPORT_SYMBOL(perf_irq);
62 * time_init() - it does the following things.
64 * 1) plat_time_init() -
65 * a) (optional) set up RTC routines,
66 * b) (optional) calibrate and set the mips_hpt_frequency
67 * (only needed if you intended to use cpu counter as timer interrupt
68 * source)
69 * 2) calculate a couple of cached variables for later usage
72 unsigned int mips_hpt_frequency;
75 * This function exists in order to cause an error due to a duplicate
76 * definition if platform code should have its own implementation. The hook
77 * to use instead is plat_time_init. plat_time_init does not receive the
78 * irqaction pointer argument anymore. This is because any function which
79 * initializes an interrupt timer now takes care of its own request_irq rsp.
80 * setup_irq calls and each clock_event_device should use its own
81 * struct irqrequest.
83 void __init plat_timer_setup(void)
85 BUG();
88 static __init int cpu_has_mfc0_count_bug(void)
90 switch (current_cpu_type()) {
91 case CPU_R4000PC:
92 case CPU_R4000SC:
93 case CPU_R4000MC:
95 * V3.0 is documented as suffering from the mfc0 from count bug.
96 * Afaik this is the last version of the R4000. Later versions
97 * were marketed as R4400.
99 return 1;
101 case CPU_R4400PC:
102 case CPU_R4400SC:
103 case CPU_R4400MC:
105 * The published errata for the R4400 up to 3.0 say the CPU
106 * has the mfc0 from count bug.
108 if ((current_cpu_data.processor_id & 0xff) <= 0x30)
109 return 1;
112 * we assume newer revisions are ok
114 return 0;
117 return 0;
120 void __init time_init(void)
122 plat_time_init();
124 if (!mips_clockevent_init() || !cpu_has_mfc0_count_bug())
125 init_mips_clocksource();