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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 CZ |
15 | #include <linux/errno.h> |
16 | #include <linux/time.h> | |
17 | #include <linux/timex.h> | |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/init.h> | |
21 | #include <linux/irq.h> | |
22 | #include <linux/profile.h> | |
23 | #include <linux/delay.h> | |
24 | ||
25 | #include <asm/timex.h> | |
26 | #include <asm/platform.h> | |
27 | ||
28 | ||
34af946a | 29 | DEFINE_SPINLOCK(rtc_lock); |
5a0015d6 CZ |
30 | EXPORT_SYMBOL(rtc_lock); |
31 | ||
32 | ||
33 | #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT | |
34 | unsigned long ccount_per_jiffy; /* per 1/HZ */ | |
2b8aea74 | 35 | unsigned long nsec_per_ccount; /* nsec per ccount increment */ |
5a0015d6 CZ |
36 | #endif |
37 | ||
5a0015d6 CZ |
38 | static long last_rtc_update = 0; |
39 | ||
2b8aea74 CZ |
40 | /* |
41 | * Scheduler clock - returns current tim in nanosec units. | |
42 | */ | |
43 | ||
44 | unsigned long long sched_clock(void) | |
45 | { | |
46 | return (unsigned long long)jiffies * (1000000000 / HZ); | |
47 | } | |
48 | ||
fd43fe19 | 49 | static irqreturn_t timer_interrupt(int irq, void *dev_id); |
5a0015d6 CZ |
50 | static struct irqaction timer_irqaction = { |
51 | .handler = timer_interrupt, | |
85ac3ab2 | 52 | .flags = IRQF_DISABLED, |
5a0015d6 CZ |
53 | .name = "timer", |
54 | }; | |
55 | ||
56 | void __init time_init(void) | |
57 | { | |
58 | time_t sec_o, sec_n = 0; | |
59 | ||
60 | /* The platform must provide a function to calibrate the processor | |
61 | * speed for the CALIBRATE. | |
62 | */ | |
63 | ||
288a60cf | 64 | #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT |
5a0015d6 CZ |
65 | printk("Calibrating CPU frequency "); |
66 | platform_calibrate_ccount(); | |
67 | printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ), | |
68 | (int)(ccount_per_jiffy/(10000/HZ))%100); | |
69 | #endif | |
70 | ||
71 | /* Set time from RTC (if provided) */ | |
72 | ||
73 | if (platform_get_rtc_time(&sec_o) == 0) | |
74 | while (platform_get_rtc_time(&sec_n)) | |
75 | if (sec_o != sec_n) | |
76 | break; | |
77 | ||
78 | xtime.tv_nsec = 0; | |
79 | last_rtc_update = xtime.tv_sec = sec_n; | |
5a0015d6 CZ |
80 | |
81 | set_normalized_timespec(&wall_to_monotonic, | |
82 | -xtime.tv_sec, -xtime.tv_nsec); | |
83 | ||
84 | /* Initialize the linux timer interrupt. */ | |
85 | ||
86 | setup_irq(LINUX_TIMER_INT, &timer_irqaction); | |
87 | set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY); | |
88 | } | |
89 | ||
90 | ||
91 | int do_settimeofday(struct timespec *tv) | |
92 | { | |
93 | time_t wtm_sec, sec = tv->tv_sec; | |
94 | long wtm_nsec, nsec = tv->tv_nsec; | |
2b8aea74 | 95 | unsigned long delta; |
5a0015d6 CZ |
96 | |
97 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) | |
98 | return -EINVAL; | |
99 | ||
100 | write_seqlock_irq(&xtime_lock); | |
101 | ||
102 | /* This is revolting. We need to set "xtime" correctly. However, the | |
103 | * value in this location is the value at the most recent update of | |
104 | * wall time. Discover what correction gettimeofday() would have | |
105 | * made, and then undo it! | |
106 | */ | |
2b8aea74 CZ |
107 | |
108 | delta = CCOUNT_PER_JIFFY; | |
109 | delta += get_ccount() - get_linux_timer(); | |
110 | nsec -= delta * NSEC_PER_CCOUNT; | |
5a0015d6 CZ |
111 | |
112 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); | |
113 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); | |
114 | ||
115 | set_normalized_timespec(&xtime, sec, nsec); | |
116 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); | |
117 | ||
b149ee22 | 118 | ntp_clear(); |
5a0015d6 CZ |
119 | write_sequnlock_irq(&xtime_lock); |
120 | return 0; | |
121 | } | |
122 | ||
123 | EXPORT_SYMBOL(do_settimeofday); | |
124 | ||
125 | ||
126 | void do_gettimeofday(struct timeval *tv) | |
127 | { | |
128 | unsigned long flags; | |
2b8aea74 | 129 | unsigned long volatile sec, usec, delta, seq; |
5a0015d6 CZ |
130 | |
131 | do { | |
132 | seq = read_seqbegin_irqsave(&xtime_lock, flags); | |
133 | ||
5a0015d6 CZ |
134 | sec = xtime.tv_sec; |
135 | usec = (xtime.tv_nsec / NSEC_PER_USEC); | |
2b8aea74 CZ |
136 | |
137 | delta = get_linux_timer() - get_ccount(); | |
138 | ||
5a0015d6 CZ |
139 | } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); |
140 | ||
2b8aea74 CZ |
141 | usec += (((unsigned long) CCOUNT_PER_JIFFY - delta) |
142 | * (unsigned long) NSEC_PER_CCOUNT) / NSEC_PER_USEC; | |
143 | ||
5a0015d6 CZ |
144 | for (; usec >= 1000000; sec++, usec -= 1000000) |
145 | ; | |
146 | ||
147 | tv->tv_sec = sec; | |
148 | tv->tv_usec = usec; | |
149 | } | |
150 | ||
151 | EXPORT_SYMBOL(do_gettimeofday); | |
152 | ||
153 | /* | |
154 | * The timer interrupt is called HZ times per second. | |
155 | */ | |
156 | ||
fd43fe19 | 157 | irqreturn_t timer_interrupt (int irq, void *dev_id) |
5a0015d6 CZ |
158 | { |
159 | ||
160 | unsigned long next; | |
161 | ||
162 | next = get_linux_timer(); | |
163 | ||
164 | again: | |
165 | while ((signed long)(get_ccount() - next) > 0) { | |
166 | ||
fd43fe19 | 167 | profile_tick(CPU_PROFILING); |
5a0015d6 | 168 | #ifndef CONFIG_SMP |
fd43fe19 | 169 | update_process_times(user_mode(get_irq_regs())); |
5a0015d6 CZ |
170 | #endif |
171 | ||
172 | write_seqlock(&xtime_lock); | |
173 | ||
2b8aea74 CZ |
174 | do_timer(1); /* Linux handler in kernel/timer.c */ |
175 | ||
176 | /* Note that writing CCOMPARE clears the interrupt. */ | |
177 | ||
5a0015d6 | 178 | next += CCOUNT_PER_JIFFY; |
2b8aea74 | 179 | set_linux_timer(next); |
5a0015d6 | 180 | |
b149ee22 | 181 | if (ntp_synced() && |
5a0015d6 | 182 | xtime.tv_sec - last_rtc_update >= 659 && |
8ef38609 | 183 | abs((xtime.tv_nsec/1000)-(1000000-1000000/HZ))<5000000/HZ) { |
5a0015d6 CZ |
184 | |
185 | if (platform_set_rtc_time(xtime.tv_sec+1) == 0) | |
186 | last_rtc_update = xtime.tv_sec+1; | |
187 | else | |
188 | /* Do it again in 60 s */ | |
189 | last_rtc_update += 60; | |
190 | } | |
191 | write_sequnlock(&xtime_lock); | |
192 | } | |
193 | ||
2b8aea74 | 194 | /* Allow platform to do something useful (Wdog). */ |
5a0015d6 | 195 | |
2b8aea74 | 196 | platform_heartbeat(); |
5a0015d6 CZ |
197 | |
198 | /* Make sure we didn't miss any tick... */ | |
199 | ||
200 | if ((signed long)(get_ccount() - next) > 0) | |
201 | goto again; | |
202 | ||
5a0015d6 CZ |
203 | return IRQ_HANDLED; |
204 | } | |
205 | ||
206 | #ifndef CONFIG_GENERIC_CALIBRATE_DELAY | |
6c81c32f | 207 | void __cpuinit calibrate_delay(void) |
5a0015d6 CZ |
208 | { |
209 | loops_per_jiffy = CCOUNT_PER_JIFFY; | |
210 | printk("Calibrating delay loop (skipped)... " | |
211 | "%lu.%02lu BogoMIPS preset\n", | |
212 | loops_per_jiffy/(1000000/HZ), | |
213 | (loops_per_jiffy/(10000/HZ)) % 100); | |
214 | } | |
215 | #endif | |
216 |