[PATCH] xtensa: fix irq and misc fixes
[linux-2.6.git] / arch / xtensa / kernel / time.c
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
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
29 DEFINE_SPINLOCK(rtc_lock);
30 EXPORT_SYMBOL(rtc_lock);
31
32
33 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
34 unsigned long ccount_per_jiffy;         /* per 1/HZ */
35 unsigned long ccount_nsec;              /* nsec per ccount increment */
36 #endif
37
38 unsigned int last_ccount_stamp;
39 static long last_rtc_update = 0;
40
41 /*
42  * Scheduler clock - returns current tim in nanosec units.
43  */
44
45 unsigned long long sched_clock(void)
46 {
47         return (unsigned long long)jiffies * (1000000000 / HZ);
48 }
49
50 static irqreturn_t timer_interrupt(int irq, void *dev_id);
51 static struct irqaction timer_irqaction = {
52         .handler =      timer_interrupt,
53         .flags =        IRQF_DISABLED,
54         .name =         "timer",
55 };
56
57 void __init time_init(void)
58 {
59         time_t sec_o, sec_n = 0;
60
61         /* The platform must provide a function to calibrate the processor
62          * speed for the CALIBRATE.
63          */
64
65 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
66         printk("Calibrating CPU frequency ");
67         platform_calibrate_ccount();
68         printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ),
69                         (int)(ccount_per_jiffy/(10000/HZ))%100);
70 #endif
71
72         /* Set time from RTC (if provided) */
73
74         if (platform_get_rtc_time(&sec_o) == 0)
75                 while (platform_get_rtc_time(&sec_n))
76                         if (sec_o != sec_n)
77                                 break;
78
79         xtime.tv_nsec = 0;
80         last_rtc_update = xtime.tv_sec = sec_n;
81         last_ccount_stamp = get_ccount();
82
83         set_normalized_timespec(&wall_to_monotonic,
84                 -xtime.tv_sec, -xtime.tv_nsec);
85
86         /* Initialize the linux timer interrupt. */
87
88         setup_irq(LINUX_TIMER_INT, &timer_irqaction);
89         set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY);
90 }
91
92
93 int do_settimeofday(struct timespec *tv)
94 {
95         time_t wtm_sec, sec = tv->tv_sec;
96         long wtm_nsec, nsec = tv->tv_nsec;
97         unsigned long ccount;
98
99         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
100                 return -EINVAL;
101
102         write_seqlock_irq(&xtime_lock);
103
104         /* This is revolting. We need to set "xtime" correctly. However, the
105          * value in this location is the value at the most recent update of
106          * wall time.  Discover what correction gettimeofday() would have
107          * made, and then undo it!
108          */
109         ccount = get_ccount();
110         nsec -= (ccount - last_ccount_stamp) * CCOUNT_NSEC;
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
118         ntp_clear();
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;
129         unsigned long sec, usec, delta, seq;
130
131         do {
132                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
133
134                 delta = get_ccount() - last_ccount_stamp;
135                 sec = xtime.tv_sec;
136                 usec = (xtime.tv_nsec / NSEC_PER_USEC);
137         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
138
139         usec += (delta * CCOUNT_NSEC) / NSEC_PER_USEC;
140         for (; usec >= 1000000; sec++, usec -= 1000000)
141                 ;
142
143         tv->tv_sec = sec;
144         tv->tv_usec = usec;
145 }
146
147 EXPORT_SYMBOL(do_gettimeofday);
148
149 /*
150  * The timer interrupt is called HZ times per second.
151  */
152
153 irqreturn_t timer_interrupt (int irq, void *dev_id)
154 {
155
156         unsigned long next;
157
158         next = get_linux_timer();
159
160 again:
161         while ((signed long)(get_ccount() - next) > 0) {
162
163                 profile_tick(CPU_PROFILING);
164 #ifndef CONFIG_SMP
165                 update_process_times(user_mode(get_irq_regs()));
166 #endif
167
168                 write_seqlock(&xtime_lock);
169
170                 last_ccount_stamp = next;
171                 next += CCOUNT_PER_JIFFY;
172                 do_timer (1); /* Linux handler in kernel/timer.c */
173
174                 if (ntp_synced() &&
175                     xtime.tv_sec - last_rtc_update >= 659 &&
176                     abs((xtime.tv_nsec/1000)-(1000000-1000000/HZ))<5000000/HZ) {
177
178                         if (platform_set_rtc_time(xtime.tv_sec+1) == 0)
179                                 last_rtc_update = xtime.tv_sec+1;
180                         else
181                                 /* Do it again in 60 s */
182                                 last_rtc_update += 60;
183                 }
184                 write_sequnlock(&xtime_lock);
185         }
186
187         /* NOTE: writing CCOMPAREn clears the interrupt.  */
188
189         set_linux_timer (next);
190
191         /* Make sure we didn't miss any tick... */
192
193         if ((signed long)(get_ccount() - next) > 0)
194                 goto again;
195
196         /* Allow platform to do something useful (Wdog). */
197
198         platform_heartbeat();
199
200         return IRQ_HANDLED;
201 }
202
203 #ifndef CONFIG_GENERIC_CALIBRATE_DELAY
204 void __devinit calibrate_delay(void)
205 {
206         loops_per_jiffy = CCOUNT_PER_JIFFY;
207         printk("Calibrating delay loop (skipped)... "
208                "%lu.%02lu BogoMIPS preset\n",
209                loops_per_jiffy/(1000000/HZ),
210                (loops_per_jiffy/(10000/HZ)) % 100);
211 }
212 #endif
213