Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/arch/arm26/kernel/time.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1995 Linus Torvalds | |
5 | * Modifications for ARM (C) 1994-2001 Russell King | |
6 | * Mods for ARM26 (C) 2003 Ian Molton | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
12 | * This file contains the ARM-specific time handling details: | |
13 | * reading the RTC at bootup, etc... | |
14 | * | |
15 | * 1994-07-02 Alan Modra | |
16 | * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime | |
17 | * 1998-12-20 Updated NTP code according to technical memorandum Jan '96 | |
18 | * "A Kernel Model for Precision Timekeeping" by Dave Mills | |
19 | */ | |
20 | ||
21 | #include <linux/config.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/kernel.h> | |
24 | #include <linux/interrupt.h> | |
25 | #include <linux/time.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/smp.h> | |
28 | #include <linux/timex.h> | |
29 | #include <linux/errno.h> | |
30 | #include <linux/profile.h> | |
31 | ||
32 | #include <asm/hardware.h> | |
33 | #include <asm/io.h> | |
34 | #include <asm/irq.h> | |
35 | #include <asm/ioc.h> | |
36 | ||
1da177e4 LT |
37 | extern unsigned long wall_jiffies; |
38 | ||
39 | /* this needs a better home */ | |
40 | DEFINE_SPINLOCK(rtc_lock); | |
41 | ||
42 | /* change this if you have some constant time drift */ | |
43 | #define USECS_PER_JIFFY (1000000/HZ) | |
44 | ||
45 | static int dummy_set_rtc(void) | |
46 | { | |
47 | return 0; | |
48 | } | |
49 | ||
50 | /* | |
51 | * hook for setting the RTC's idea of the current time. | |
52 | */ | |
53 | int (*set_rtc)(void) = dummy_set_rtc; | |
54 | ||
55 | /* | |
56 | * Get time offset based on IOCs timer. | |
57 | * FIXME - if this is called with interrutps off, why the shennanigans | |
58 | * below ? | |
59 | */ | |
60 | static unsigned long gettimeoffset(void) | |
61 | { | |
62 | unsigned int count1, count2, status; | |
63 | long offset; | |
64 | ||
65 | ioc_writeb (0, IOC_T0LATCH); | |
66 | barrier (); | |
67 | count1 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8); | |
68 | barrier (); | |
69 | status = ioc_readb(IOC_IRQREQA); | |
70 | barrier (); | |
71 | ioc_writeb (0, IOC_T0LATCH); | |
72 | barrier (); | |
73 | count2 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8); | |
74 | ||
75 | offset = count2; | |
76 | if (count2 < count1) { | |
77 | /* | |
78 | * We have not had an interrupt between reading count1 | |
79 | * and count2. | |
80 | */ | |
81 | if (status & (1 << 5)) | |
82 | offset -= LATCH; | |
83 | } else if (count2 > count1) { | |
84 | /* | |
85 | * We have just had another interrupt between reading | |
86 | * count1 and count2. | |
87 | */ | |
88 | offset -= LATCH; | |
89 | } | |
90 | ||
91 | offset = (LATCH - offset) * (tick_nsec / 1000); | |
92 | return (offset + LATCH/2) / LATCH; | |
93 | } | |
94 | ||
95 | /* | |
96 | * Scheduler clock - returns current time in nanosec units. | |
97 | */ | |
98 | unsigned long long sched_clock(void) | |
99 | { | |
100 | return (unsigned long long)jiffies * (1000000000 / HZ); | |
101 | } | |
102 | ||
103 | static unsigned long next_rtc_update; | |
104 | ||
105 | /* | |
106 | * If we have an externally synchronized linux clock, then update | |
107 | * CMOS clock accordingly every ~11 minutes. set_rtc() has to be | |
108 | * called as close as possible to 500 ms before the new second | |
109 | * starts. | |
110 | */ | |
111 | static inline void do_set_rtc(void) | |
112 | { | |
b149ee22 | 113 | if (!ntp_synced() || set_rtc == NULL) |
1da177e4 LT |
114 | return; |
115 | ||
116 | //FIXME - timespec.tv_sec is a time_t not unsigned long | |
117 | if (next_rtc_update && | |
118 | time_before((unsigned long)xtime.tv_sec, next_rtc_update)) | |
119 | return; | |
120 | ||
121 | if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) && | |
122 | xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1)) | |
123 | return; | |
124 | ||
125 | if (set_rtc()) | |
126 | /* | |
127 | * rtc update failed. Try again in 60s | |
128 | */ | |
129 | next_rtc_update = xtime.tv_sec + 60; | |
130 | else | |
131 | next_rtc_update = xtime.tv_sec + 660; | |
132 | } | |
133 | ||
134 | #define do_leds() | |
135 | ||
136 | void do_gettimeofday(struct timeval *tv) | |
137 | { | |
138 | unsigned long flags; | |
139 | unsigned long seq; | |
140 | unsigned long usec, sec, lost; | |
141 | ||
142 | do { | |
143 | seq = read_seqbegin_irqsave(&xtime_lock, flags); | |
144 | usec = gettimeoffset(); | |
145 | ||
146 | lost = jiffies - wall_jiffies; | |
147 | if (lost) | |
148 | usec += lost * USECS_PER_JIFFY; | |
149 | ||
150 | sec = xtime.tv_sec; | |
151 | usec += xtime.tv_nsec / 1000; | |
152 | } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); | |
153 | ||
154 | /* usec may have gone up a lot: be safe */ | |
155 | while (usec >= 1000000) { | |
156 | usec -= 1000000; | |
157 | sec++; | |
158 | } | |
159 | ||
160 | tv->tv_sec = sec; | |
161 | tv->tv_usec = usec; | |
162 | } | |
163 | ||
164 | EXPORT_SYMBOL(do_gettimeofday); | |
165 | ||
166 | int do_settimeofday(struct timespec *tv) | |
167 | { | |
168 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
169 | return -EINVAL; | |
170 | ||
171 | write_seqlock_irq(&xtime_lock); | |
172 | /* | |
173 | * This is revolting. We need to set "xtime" correctly. However, the | |
174 | * value in this location is the value at the most recent update of | |
175 | * wall time. Discover what correction gettimeofday() would have | |
176 | * done, and then undo it! | |
177 | */ | |
178 | tv->tv_nsec -= 1000 * (gettimeoffset() + | |
179 | (jiffies - wall_jiffies) * USECS_PER_JIFFY); | |
180 | ||
181 | while (tv->tv_nsec < 0) { | |
182 | tv->tv_nsec += NSEC_PER_SEC; | |
183 | tv->tv_sec--; | |
184 | } | |
185 | ||
186 | xtime.tv_sec = tv->tv_sec; | |
187 | xtime.tv_nsec = tv->tv_nsec; | |
b149ee22 | 188 | ntp_clear(); |
1da177e4 LT |
189 | write_sequnlock_irq(&xtime_lock); |
190 | clock_was_set(); | |
191 | return 0; | |
192 | } | |
193 | ||
194 | EXPORT_SYMBOL(do_settimeofday); | |
195 | ||
196 | static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) | |
197 | { | |
198 | do_timer(regs); | |
199 | #ifndef CONFIG_SMP | |
200 | update_process_times(user_mode(regs)); | |
201 | #endif | |
202 | do_set_rtc(); //FIME - EVERY timer IRQ? | |
203 | profile_tick(CPU_PROFILING, regs); | |
204 | return IRQ_HANDLED; //FIXME - is this right? | |
205 | } | |
206 | ||
207 | static struct irqaction timer_irq = { | |
208 | .name = "timer", | |
209 | .flags = SA_INTERRUPT, | |
210 | .handler = timer_interrupt, | |
211 | }; | |
212 | ||
213 | extern void ioctime_init(void); | |
214 | ||
215 | /* | |
216 | * Set up timer interrupt. | |
217 | */ | |
218 | void __init time_init(void) | |
219 | { | |
220 | ioc_writeb(LATCH & 255, IOC_T0LTCHL); | |
221 | ioc_writeb(LATCH >> 8, IOC_T0LTCHH); | |
222 | ioc_writeb(0, IOC_T0GO); | |
223 | ||
224 | ||
225 | setup_irq(IRQ_TIMER, &timer_irq); | |
226 | } | |
227 |