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
6 * Common time service routines for MIPS machines. See
7 * Documentation/mips/time.README.
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the
11 * Free Software Foundation; either version 2 of the License, or (at your
12 * option) any later version.
14 #include <linux/clocksource.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/kernel_stat.h>
24 #include <linux/spinlock.h>
25 #include <linux/interrupt.h>
26 #include <linux/module.h>
28 #include <asm/bootinfo.h>
29 #include <asm/cache.h>
30 #include <asm/compiler.h>
32 #include <asm/cpu-features.h>
33 #include <asm/div64.h>
34 #include <asm/sections.h>
38 * The integer part of the number of usecs per jiffy is taken from tick,
39 * but the fractional part is not recorded, so we calculate it using the
40 * initial value of HZ. This aids systems where tick isn't really an
41 * integer (e.g. for HZ = 128).
43 #define USECS_PER_JIFFY TICK_SIZE
44 #define USECS_PER_JIFFY_FRAC ((unsigned long)(u32)((1000000ULL << 32) / HZ))
46 #define TICK_SIZE (tick_nsec / 1000)
51 DEFINE_SPINLOCK(rtc_lock
);
54 * By default we provide the null RTC ops
56 static unsigned long null_rtc_get_time(void)
58 return mktime(2000, 1, 1, 0, 0, 0);
61 static int null_rtc_set_time(unsigned long sec
)
66 unsigned long (*rtc_mips_get_time
)(void) = null_rtc_get_time
;
67 int (*rtc_mips_set_time
)(unsigned long) = null_rtc_set_time
;
68 int (*rtc_mips_set_mmss
)(unsigned long);
71 /* how many counter cycles in a jiffy */
72 static unsigned long cycles_per_jiffy __read_mostly
;
74 /* expirelo is the count value for next CPU timer interrupt */
75 static unsigned int expirelo
;
79 * Null timer ack for systems not needing one (e.g. i8254).
81 static void null_timer_ack(void) { /* nothing */ }
84 * Null high precision timer functions for systems lacking one.
86 static unsigned int null_hpt_read(void)
92 * Timer ack for an R4k-compatible timer of a known frequency.
94 static void c0_timer_ack(void)
98 #ifndef CONFIG_SOC_PNX8550 /* pnx8550 resets to zero */
99 /* Ack this timer interrupt and set the next one. */
100 expirelo
+= cycles_per_jiffy
;
102 write_c0_compare(expirelo
);
104 /* Check to see if we have missed any timer interrupts. */
105 while (((count
= read_c0_count()) - expirelo
) < 0x7fffffff) {
106 /* missed_timer_count++; */
107 expirelo
= count
+ cycles_per_jiffy
;
108 write_c0_compare(expirelo
);
113 * High precision timer functions for a R4k-compatible timer.
115 static unsigned int c0_hpt_read(void)
117 return read_c0_count();
120 /* For use both as a high precision timer and an interrupt source. */
121 static void __init
c0_hpt_timer_init(void)
123 expirelo
= read_c0_count() + cycles_per_jiffy
;
124 write_c0_compare(expirelo
);
127 int (*mips_timer_state
)(void);
128 void (*mips_timer_ack
)(void);
129 unsigned int (*mips_hpt_read
)(void);
130 unsigned int mips_hpt_mask
= 0xffffffff;
132 /* last time when xtime and rtc are sync'ed up */
133 static long last_rtc_update
;
136 * local_timer_interrupt() does profiling and process accounting
137 * on a per-CPU basis.
139 * In UP mode, it is invoked from the (global) timer_interrupt.
141 * In SMP mode, it might invoked by per-CPU timer interrupt, or
142 * a broadcasted inter-processor interrupt which itself is triggered
143 * by the global timer interrupt.
145 void local_timer_interrupt(int irq
, void *dev_id
)
147 profile_tick(CPU_PROFILING
);
148 update_process_times(user_mode(get_irq_regs()));
152 * High-level timer interrupt service routines. This function
153 * is set as irqaction->handler and is invoked through do_IRQ.
155 irqreturn_t
timer_interrupt(int irq
, void *dev_id
)
157 write_seqlock(&xtime_lock
);
162 * call the generic timer interrupt handling
167 * If we have an externally synchronized Linux clock, then update
168 * CMOS clock accordingly every ~11 minutes. rtc_mips_set_time() has to be
169 * called as close as possible to 500 ms before the new second starts.
172 xtime
.tv_sec
> last_rtc_update
+ 660 &&
173 (xtime
.tv_nsec
/ 1000) >= 500000 - ((unsigned) TICK_SIZE
) / 2 &&
174 (xtime
.tv_nsec
/ 1000) <= 500000 + ((unsigned) TICK_SIZE
) / 2) {
175 if (rtc_mips_set_mmss(xtime
.tv_sec
) == 0) {
176 last_rtc_update
= xtime
.tv_sec
;
178 /* do it again in 60 s */
179 last_rtc_update
= xtime
.tv_sec
- 600;
183 write_sequnlock(&xtime_lock
);
186 * In UP mode, we call local_timer_interrupt() to do profiling
187 * and process accouting.
189 * In SMP mode, local_timer_interrupt() is invoked by appropriate
190 * low-level local timer interrupt handler.
192 local_timer_interrupt(irq
, dev_id
);
197 int null_perf_irq(void)
202 int (*perf_irq
)(void) = null_perf_irq
;
204 EXPORT_SYMBOL(null_perf_irq
);
205 EXPORT_SYMBOL(perf_irq
);
207 asmlinkage
void ll_timer_interrupt(int irq
)
209 int r2
= cpu_has_mips_r2
;
212 kstat_this_cpu
.irqs
[irq
]++;
216 * Before R2 of the architecture there was no way to see if a
217 * performance counter interrupt was pending, so we have to run the
218 * performance counter interrupt handler anyway.
220 if (!r2
|| (read_c0_cause() & (1 << 26)))
224 /* we keep interrupt disabled all the time */
225 if (!r2
|| (read_c0_cause() & (1 << 30)))
226 timer_interrupt(irq
, NULL
);
232 asmlinkage
void ll_local_timer_interrupt(int irq
)
235 if (smp_processor_id() != 0)
236 kstat_this_cpu
.irqs
[irq
]++;
238 /* we keep interrupt disabled all the time */
239 local_timer_interrupt(irq
, NULL
);
245 * time_init() - it does the following things.
247 * 1) board_time_init() -
248 * a) (optional) set up RTC routines,
249 * b) (optional) calibrate and set the mips_hpt_frequency
250 * (only needed if you intended to use cpu counter as timer interrupt
252 * 2) setup xtime based on rtc_mips_get_time().
253 * 3) calculate a couple of cached variables for later usage
254 * 4) plat_timer_setup() -
255 * a) (optional) over-write any choices made above by time_init().
256 * b) machine specific code should setup the timer irqaction.
257 * c) enable the timer interrupt
260 void (*board_time_init
)(void);
262 unsigned int mips_hpt_frequency
;
264 static struct irqaction timer_irqaction
= {
265 .handler
= timer_interrupt
,
266 .flags
= IRQF_DISABLED
,
270 static unsigned int __init
calibrate_hpt(void)
273 u32 hpt_start
, hpt_end
, hpt_count
, hz
;
275 const int loops
= HZ
/ 10;
280 * We want to calibrate for 0.1s, but to avoid a 64-bit
281 * division we round the number of loops up to the nearest
284 while (loops
> 1 << log_2_loops
)
286 i
= 1 << log_2_loops
;
289 * Wait for a rising edge of the timer interrupt.
291 while (mips_timer_state());
292 while (!mips_timer_state());
295 * Now see how many high precision timer ticks happen
296 * during the calculated number of periods between timer
299 hpt_start
= mips_hpt_read();
301 while (mips_timer_state());
302 while (!mips_timer_state());
304 hpt_end
= mips_hpt_read();
306 hpt_count
= (hpt_end
- hpt_start
) & mips_hpt_mask
;
308 frequency
= (u64
)hpt_count
* (u64
)hz
;
310 return frequency
>> log_2_loops
;
313 static cycle_t
read_mips_hpt(void)
315 return (cycle_t
)mips_hpt_read();
318 static struct clocksource clocksource_mips
= {
320 .read
= read_mips_hpt
,
324 static void __init
init_mips_clocksource(void)
329 if (!mips_hpt_frequency
|| mips_hpt_read
== null_hpt_read
)
332 /* Calclate a somewhat reasonable rating value */
333 clocksource_mips
.rating
= 200 + mips_hpt_frequency
/ 10000000;
334 /* Find a shift value */
335 for (shift
= 32; shift
> 0; shift
--) {
336 temp
= (u64
) NSEC_PER_SEC
<< shift
;
337 do_div(temp
, mips_hpt_frequency
);
338 if ((temp
>> 32) == 0)
341 clocksource_mips
.shift
= shift
;
342 clocksource_mips
.mult
= (u32
)temp
;
343 clocksource_mips
.mask
= mips_hpt_mask
;
345 clocksource_register(&clocksource_mips
);
348 void __init
time_init(void)
353 if (!rtc_mips_set_mmss
)
354 rtc_mips_set_mmss
= rtc_mips_set_time
;
356 xtime
.tv_sec
= rtc_mips_get_time();
359 set_normalized_timespec(&wall_to_monotonic
,
360 -xtime
.tv_sec
, -xtime
.tv_nsec
);
362 /* Choose appropriate high precision timer routines. */
363 if (!cpu_has_counter
&& !mips_hpt_read
)
364 /* No high precision timer -- sorry. */
365 mips_hpt_read
= null_hpt_read
;
366 else if (!mips_hpt_frequency
&& !mips_timer_state
) {
367 /* A high precision timer of unknown frequency. */
369 /* No external high precision timer -- use R4k. */
370 mips_hpt_read
= c0_hpt_read
;
372 /* We know counter frequency. Or we can get it. */
373 if (!mips_hpt_read
) {
374 /* No external high precision timer -- use R4k. */
375 mips_hpt_read
= c0_hpt_read
;
377 if (!mips_timer_state
) {
378 /* No external timer interrupt -- use R4k. */
379 mips_timer_ack
= c0_timer_ack
;
380 /* Calculate cache parameters. */
382 (mips_hpt_frequency
+ HZ
/ 2) / HZ
;
384 * This sets up the high precision
385 * timer for the first interrupt.
390 if (!mips_hpt_frequency
)
391 mips_hpt_frequency
= calibrate_hpt();
393 /* Report the high precision timer rate for a reference. */
394 printk("Using %u.%03u MHz high precision timer.\n",
395 ((mips_hpt_frequency
+ 500) / 1000) / 1000,
396 ((mips_hpt_frequency
+ 500) / 1000) % 1000);
400 /* No timer interrupt ack (e.g. i8254). */
401 mips_timer_ack
= null_timer_ack
;
404 * Call board specific timer interrupt setup.
406 * this pointer must be setup in machine setup routine.
408 * Even if a machine chooses to use a low-level timer interrupt,
409 * it still needs to setup the timer_irqaction.
410 * In that case, it might be better to set timer_irqaction.handler
411 * to be NULL function so that we are sure the high-level code
412 * is not invoked accidentally.
414 plat_timer_setup(&timer_irqaction
);
416 init_mips_clocksource();
420 #define STARTOFTIME 1970
421 #define SECDAY 86400L
422 #define SECYR (SECDAY * 365)
423 #define leapyear(y) ((!((y) % 4) && ((y) % 100)) || !((y) % 400))
424 #define days_in_year(y) (leapyear(y) ? 366 : 365)
425 #define days_in_month(m) (month_days[(m) - 1])
427 static int month_days
[12] = {
428 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
431 void to_tm(unsigned long tim
, struct rtc_time
*tm
)
436 gday
= day
= tim
/ SECDAY
;
439 /* Hours, minutes, seconds are easy */
440 tm
->tm_hour
= hms
/ 3600;
441 tm
->tm_min
= (hms
% 3600) / 60;
442 tm
->tm_sec
= (hms
% 3600) % 60;
444 /* Number of years in days */
445 for (i
= STARTOFTIME
; day
>= days_in_year(i
); i
++)
446 day
-= days_in_year(i
);
449 /* Number of months in days left */
450 if (leapyear(tm
->tm_year
))
451 days_in_month(FEBRUARY
) = 29;
452 for (i
= 1; day
>= days_in_month(i
); i
++)
453 day
-= days_in_month(i
);
454 days_in_month(FEBRUARY
) = 28;
455 tm
->tm_mon
= i
- 1; /* tm_mon starts from 0 to 11 */
457 /* Days are what is left over (+1) from all that. */
458 tm
->tm_mday
= day
+ 1;
461 * Determine the day of week
463 tm
->tm_wday
= (gday
+ 4) % 7; /* 1970/1/1 was Thursday */
466 EXPORT_SYMBOL(rtc_lock
);
467 EXPORT_SYMBOL(to_tm
);
468 EXPORT_SYMBOL(rtc_mips_set_time
);
469 EXPORT_SYMBOL(rtc_mips_get_time
);
471 unsigned long long sched_clock(void)
473 return (unsigned long long)jiffies
*(1000000000/HZ
);