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1da177e4 LT |
1 | /* |
2 | * linux/arch/parisc/kernel/time.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1995 Linus Torvalds | |
5 | * Modifications for ARM (C) 1994, 1995, 1996,1997 Russell King | |
6 | * Copyright (C) 1999 SuSE GmbH, (Philipp Rumpf, prumpf@tux.org) | |
7 | * | |
8 | * 1994-07-02 Alan Modra | |
9 | * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime | |
10 | * 1998-12-20 Updated NTP code according to technical memorandum Jan '96 | |
11 | * "A Kernel Model for Precision Timekeeping" by Dave Mills | |
12 | */ | |
1da177e4 LT |
13 | #include <linux/errno.h> |
14 | #include <linux/module.h> | |
15 | #include <linux/sched.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/param.h> | |
18 | #include <linux/string.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/interrupt.h> | |
21 | #include <linux/time.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/smp.h> | |
24 | #include <linux/profile.h> | |
25 | ||
26 | #include <asm/uaccess.h> | |
27 | #include <asm/io.h> | |
28 | #include <asm/irq.h> | |
29 | #include <asm/param.h> | |
30 | #include <asm/pdc.h> | |
31 | #include <asm/led.h> | |
32 | ||
33 | #include <linux/timex.h> | |
34 | ||
8039de10 HD |
35 | static long clocktick __read_mostly; /* timer cycles per tick */ |
36 | static long halftick __read_mostly; | |
1da177e4 LT |
37 | |
38 | #ifdef CONFIG_SMP | |
39 | extern void smp_do_timer(struct pt_regs *regs); | |
40 | #endif | |
41 | ||
42 | irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) | |
43 | { | |
44 | long now; | |
45 | long next_tick; | |
46 | int nticks; | |
47 | int cpu = smp_processor_id(); | |
48 | ||
49 | profile_tick(CPU_PROFILING, regs); | |
50 | ||
51 | now = mfctl(16); | |
52 | /* initialize next_tick to time at last clocktick */ | |
53 | next_tick = cpu_data[cpu].it_value; | |
54 | ||
55 | /* since time passes between the interrupt and the mfctl() | |
56 | * above, it is never true that last_tick + clocktick == now. If we | |
57 | * never miss a clocktick, we could set next_tick = last_tick + clocktick | |
58 | * but maybe we'll miss ticks, hence the loop. | |
59 | * | |
60 | * Variables are *signed*. | |
61 | */ | |
62 | ||
63 | nticks = 0; | |
64 | while((next_tick - now) < halftick) { | |
65 | next_tick += clocktick; | |
66 | nticks++; | |
67 | } | |
68 | mtctl(next_tick, 16); | |
69 | cpu_data[cpu].it_value = next_tick; | |
70 | ||
71 | while (nticks--) { | |
72 | #ifdef CONFIG_SMP | |
73 | smp_do_timer(regs); | |
74 | #else | |
75 | update_process_times(user_mode(regs)); | |
76 | #endif | |
77 | if (cpu == 0) { | |
78 | write_seqlock(&xtime_lock); | |
3171a030 | 79 | do_timer(1); |
1da177e4 LT |
80 | write_sequnlock(&xtime_lock); |
81 | } | |
82 | } | |
83 | ||
1da177e4 LT |
84 | /* check soft power switch status */ |
85 | if (cpu == 0 && !atomic_read(&power_tasklet.count)) | |
86 | tasklet_schedule(&power_tasklet); | |
87 | ||
88 | return IRQ_HANDLED; | |
89 | } | |
90 | ||
5cd55b0e RC |
91 | |
92 | unsigned long profile_pc(struct pt_regs *regs) | |
93 | { | |
94 | unsigned long pc = instruction_pointer(regs); | |
95 | ||
96 | if (regs->gr[0] & PSW_N) | |
97 | pc -= 4; | |
98 | ||
99 | #ifdef CONFIG_SMP | |
100 | if (in_lock_functions(pc)) | |
101 | pc = regs->gr[2]; | |
102 | #endif | |
103 | ||
104 | return pc; | |
105 | } | |
106 | EXPORT_SYMBOL(profile_pc); | |
107 | ||
108 | ||
1da177e4 LT |
109 | /*** converted from ia64 ***/ |
110 | /* | |
111 | * Return the number of micro-seconds that elapsed since the last | |
8ef38609 | 112 | * update to wall time (aka xtime). The xtime_lock |
1da177e4 LT |
113 | * must be at least read-locked when calling this routine. |
114 | */ | |
115 | static inline unsigned long | |
116 | gettimeoffset (void) | |
117 | { | |
118 | #ifndef CONFIG_SMP | |
119 | /* | |
120 | * FIXME: This won't work on smp because jiffies are updated by cpu 0. | |
121 | * Once parisc-linux learns the cr16 difference between processors, | |
122 | * this could be made to work. | |
123 | */ | |
124 | long last_tick; | |
125 | long elapsed_cycles; | |
126 | ||
127 | /* it_value is the intended time of the next tick */ | |
128 | last_tick = cpu_data[smp_processor_id()].it_value; | |
129 | ||
130 | /* Subtract one tick and account for possible difference between | |
131 | * when we expected the tick and when it actually arrived. | |
132 | * (aka wall vs real) | |
133 | */ | |
134 | last_tick -= clocktick * (jiffies - wall_jiffies + 1); | |
135 | elapsed_cycles = mfctl(16) - last_tick; | |
136 | ||
137 | /* the precision of this math could be improved */ | |
138 | return elapsed_cycles / (PAGE0->mem_10msec / 10000); | |
139 | #else | |
140 | return 0; | |
141 | #endif | |
142 | } | |
143 | ||
144 | void | |
145 | do_gettimeofday (struct timeval *tv) | |
146 | { | |
147 | unsigned long flags, seq, usec, sec; | |
148 | ||
149 | do { | |
150 | seq = read_seqbegin_irqsave(&xtime_lock, flags); | |
151 | usec = gettimeoffset(); | |
152 | sec = xtime.tv_sec; | |
153 | usec += (xtime.tv_nsec / 1000); | |
154 | } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); | |
155 | ||
61c34016 JB |
156 | if (unlikely(usec > LONG_MAX)) { |
157 | /* This can happen if the gettimeoffset adjustment is | |
158 | * negative and xtime.tv_nsec is smaller than the | |
159 | * adjustment */ | |
160 | printk(KERN_ERR "do_gettimeofday() spurious xtime.tv_nsec of %ld\n", usec); | |
161 | usec += USEC_PER_SEC; | |
162 | --sec; | |
163 | /* This should never happen, it means the negative | |
164 | * time adjustment was more than a second, so there's | |
165 | * something seriously wrong */ | |
166 | BUG_ON(usec > LONG_MAX); | |
167 | } | |
168 | ||
169 | ||
170 | while (usec >= USEC_PER_SEC) { | |
171 | usec -= USEC_PER_SEC; | |
1da177e4 LT |
172 | ++sec; |
173 | } | |
174 | ||
175 | tv->tv_sec = sec; | |
176 | tv->tv_usec = usec; | |
177 | } | |
178 | ||
179 | EXPORT_SYMBOL(do_gettimeofday); | |
180 | ||
181 | int | |
182 | do_settimeofday (struct timespec *tv) | |
183 | { | |
184 | time_t wtm_sec, sec = tv->tv_sec; | |
185 | long wtm_nsec, nsec = tv->tv_nsec; | |
186 | ||
187 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
188 | return -EINVAL; | |
189 | ||
190 | write_seqlock_irq(&xtime_lock); | |
191 | { | |
192 | /* | |
193 | * This is revolting. We need to set "xtime" | |
194 | * correctly. However, the value in this location is | |
195 | * the value at the most recent update of wall time. | |
196 | * Discover what correction gettimeofday would have | |
197 | * done, and then undo it! | |
198 | */ | |
199 | nsec -= gettimeoffset() * 1000; | |
200 | ||
201 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); | |
202 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); | |
203 | ||
204 | set_normalized_timespec(&xtime, sec, nsec); | |
205 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
206 | ||
b149ee22 | 207 | ntp_clear(); |
1da177e4 LT |
208 | } |
209 | write_sequnlock_irq(&xtime_lock); | |
210 | clock_was_set(); | |
211 | return 0; | |
212 | } | |
213 | EXPORT_SYMBOL(do_settimeofday); | |
214 | ||
215 | /* | |
216 | * XXX: We can do better than this. | |
217 | * Returns nanoseconds | |
218 | */ | |
219 | ||
220 | unsigned long long sched_clock(void) | |
221 | { | |
222 | return (unsigned long long)jiffies * (1000000000 / HZ); | |
223 | } | |
224 | ||
225 | ||
56f335c8 GG |
226 | void __init start_cpu_itimer(void) |
227 | { | |
228 | unsigned int cpu = smp_processor_id(); | |
229 | unsigned long next_tick = mfctl(16) + clocktick; | |
230 | ||
231 | mtctl(next_tick, 16); /* kick off Interval Timer (CR16) */ | |
232 | ||
233 | cpu_data[cpu].it_value = next_tick; | |
234 | } | |
235 | ||
1da177e4 LT |
236 | void __init time_init(void) |
237 | { | |
1da177e4 LT |
238 | static struct pdc_tod tod_data; |
239 | ||
240 | clocktick = (100 * PAGE0->mem_10msec) / HZ; | |
241 | halftick = clocktick / 2; | |
242 | ||
56f335c8 | 243 | start_cpu_itimer(); /* get CPU 0 started */ |
1da177e4 LT |
244 | |
245 | if(pdc_tod_read(&tod_data) == 0) { | |
246 | write_seqlock_irq(&xtime_lock); | |
247 | xtime.tv_sec = tod_data.tod_sec; | |
248 | xtime.tv_nsec = tod_data.tod_usec * 1000; | |
249 | set_normalized_timespec(&wall_to_monotonic, | |
250 | -xtime.tv_sec, -xtime.tv_nsec); | |
251 | write_sequnlock_irq(&xtime_lock); | |
252 | } else { | |
253 | printk(KERN_ERR "Error reading tod clock\n"); | |
254 | xtime.tv_sec = 0; | |
255 | xtime.tv_nsec = 0; | |
256 | } | |
257 | } | |
258 |