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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2001 MontaVista Software Inc.
4 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
5 * Copyright (c) 2003, 2004 Maciej W. Rozycki
6 *
7 * Common time service routines for MIPS machines.
8 */
9#include <linux/bug.h>
10#include <linux/clockchips.h>
11#include <linux/types.h>
12#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/sched.h>
15#include <linux/param.h>
16#include <linux/time.h>
17#include <linux/timex.h>
18#include <linux/smp.h>
19#include <linux/spinlock.h>
20#include <linux/export.h>
21
22#include <asm/cpu-features.h>
23#include <asm/cpu-type.h>
24#include <asm/div64.h>
25#include <asm/time.h>
26
27/*
28 * forward reference
29 */
30DEFINE_SPINLOCK(rtc_lock);
31EXPORT_SYMBOL(rtc_lock);
32
33static int null_perf_irq(void)
34{
35 return 0;
36}
37
38int (*perf_irq)(void) = null_perf_irq;
39
40EXPORT_SYMBOL(perf_irq);
41
42/*
43 * time_init() - it does the following things.
44 *
45 * 1) plat_time_init() -
46 * a) (optional) set up RTC routines,
47 * b) (optional) calibrate and set the mips_hpt_frequency
48 * (only needed if you intended to use cpu counter as timer interrupt
49 * source)
50 * 2) calculate a couple of cached variables for later usage
51 */
52
53unsigned int mips_hpt_frequency;
54EXPORT_SYMBOL_GPL(mips_hpt_frequency);
55
56static __init int cpu_has_mfc0_count_bug(void)
57{
58 switch (current_cpu_type()) {
59 case CPU_R4000PC:
60 case CPU_R4000SC:
61 case CPU_R4000MC:
62 /*
63 * V3.0 is documented as suffering from the mfc0 from count bug.
64 * Afaik this is the last version of the R4000. Later versions
65 * were marketed as R4400.
66 */
67 return 1;
68
69 case CPU_R4400PC:
70 case CPU_R4400SC:
71 case CPU_R4400MC:
72 /*
73 * The published errata for the R4400 up to 3.0 say the CPU
74 * has the mfc0 from count bug.
75 */
76 if ((current_cpu_data.processor_id & 0xff) <= 0x30)
77 return 1;
78
79 /*
80 * we assume newer revisions are ok
81 */
82 return 0;
83 }
84
85 return 0;
86}
87
88void __init time_init(void)
89{
90 plat_time_init();
91
92 /*
93 * The use of the R4k timer as a clock event takes precedence;
94 * if reading the Count register might interfere with the timer
95 * interrupt, then we don't use the timer as a clock source.
96 * We may still use the timer as a clock source though if the
97 * timer interrupt isn't reliable; the interference doesn't
98 * matter then, because we don't use the interrupt.
99 */
100 if (mips_clockevent_init() != 0 || !cpu_has_mfc0_count_bug())
101 init_mips_clocksource();
102}
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
5 *
6 * Common time service routines for MIPS machines.
7 *
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.
12 */
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>
25
26#include <asm/cpu-features.h>
27#include <asm/cpu-type.h>
28#include <asm/div64.h>
29#include <asm/time.h>
30
31/*
32 * forward reference
33 */
34DEFINE_SPINLOCK(rtc_lock);
35EXPORT_SYMBOL(rtc_lock);
36
37int __weak rtc_mips_set_time(unsigned long sec)
38{
39 return -ENODEV;
40}
41
42int __weak rtc_mips_set_mmss(unsigned long nowtime)
43{
44 return rtc_mips_set_time(nowtime);
45}
46
47int update_persistent_clock(struct timespec now)
48{
49 return rtc_mips_set_mmss(now.tv_sec);
50}
51
52static int null_perf_irq(void)
53{
54 return 0;
55}
56
57int (*perf_irq)(void) = null_perf_irq;
58
59EXPORT_SYMBOL(perf_irq);
60
61/*
62 * time_init() - it does the following things.
63 *
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
70 */
71
72unsigned int mips_hpt_frequency;
73EXPORT_SYMBOL_GPL(mips_hpt_frequency);
74
75static __init int cpu_has_mfc0_count_bug(void)
76{
77 switch (current_cpu_type()) {
78 case CPU_R4000PC:
79 case CPU_R4000SC:
80 case CPU_R4000MC:
81 /*
82 * V3.0 is documented as suffering from the mfc0 from count bug.
83 * Afaik this is the last version of the R4000. Later versions
84 * were marketed as R4400.
85 */
86 return 1;
87
88 case CPU_R4400PC:
89 case CPU_R4400SC:
90 case CPU_R4400MC:
91 /*
92 * The published errata for the R4400 up to 3.0 say the CPU
93 * has the mfc0 from count bug.
94 */
95 if ((current_cpu_data.processor_id & 0xff) <= 0x30)
96 return 1;
97
98 /*
99 * we assume newer revisions are ok
100 */
101 return 0;
102 }
103
104 return 0;
105}
106
107void __init time_init(void)
108{
109 plat_time_init();
110
111 /*
112 * The use of the R4k timer as a clock event takes precedence;
113 * if reading the Count register might interfere with the timer
114 * interrupt, then we don't use the timer as a clock source.
115 * We may still use the timer as a clock source though if the
116 * timer interrupt isn't reliable; the interference doesn't
117 * matter then, because we don't use the interrupt.
118 */
119 if (mips_clockevent_init() != 0 || !cpu_has_mfc0_count_bug())
120 init_mips_clocksource();
121}