1/*
2 * BK Id: SCCS/s.time.h 1.17 10/23/01 08:09:35 trini
3 */
4/*
5 * Common time prototypes and such for all ppc machines.
6 *
7 * Written by Cort Dougan (cort@fsmlabs.com) to merge
8 * Paul Mackerras' version and mine for PReP and Pmac.
9 */
10
11#ifdef __KERNEL__
12#ifndef __ASM_TIME_H__
13#define __ASM_TIME_H__
14
15#include <linux/config.h>
16#include <linux/mc146818rtc.h>
17#include <linux/threads.h>
18
19#include <asm/processor.h>
20
21/* time.c */
22extern unsigned tb_ticks_per_jiffy;
23extern unsigned tb_to_us;
24extern unsigned tb_last_stamp;
25extern unsigned long disarm_decr[NR_CPUS];
26
27extern void to_tm(int tim, struct rtc_time * tm);
28extern time_t last_rtc_update;
29
30extern void set_dec_cpu6(unsigned int val);
31
32int via_calibrate_decr(void);
33
34/* Accessor functions for the decrementer register.
35 * The 4xx doesn't even have a decrementer.  I tried to use the
36 * generic timer interrupt code, which seems OK, with the 4xx PIT
37 * in auto-reload mode.  The problem is PIT stops counting when it
38 * hits zero.  If it would wrap, we could use it just like a decrementer.
39 */
40static __inline__ unsigned int get_dec(void)
41{
42#if defined(CONFIG_4xx)
43	return (mfspr(SPRN_PIT));
44#else
45	return (mfspr(SPRN_DEC));
46#endif
47}
48
49static __inline__ void set_dec(unsigned int val)
50{
51#if defined(CONFIG_4xx)
52	return;		/* Have to let it auto-reload */
53#elif defined(CONFIG_8xx_CPU6)
54	set_dec_cpu6(val);
55#else
56	mtspr(SPRN_DEC, val);
57#endif
58}
59
60/* Accessor functions for the timebase (RTC on 601) registers. */
61/* If one day CONFIG_POWER is added just define __USE_RTC as 1 */
62#ifdef CONFIG_6xx
63extern __inline__ int const __USE_RTC(void) {
64	return (mfspr(SPRN_PVR)>>16) == 1;
65}
66#else
67#define __USE_RTC() 0
68#endif
69
70extern __inline__ unsigned long get_tbl(void) {
71	unsigned long tbl;
72	asm volatile("mftb %0" : "=r" (tbl));
73	return tbl;
74}
75
76extern __inline__ unsigned long get_tbu(void) {
77	unsigned long tbl;
78	asm volatile("mftbu %0" : "=r" (tbl));
79	return tbl;
80}
81
82extern __inline__ void set_tb(unsigned int upper, unsigned int lower)
83{
84	mtspr(SPRN_TBWL, 0);
85	mtspr(SPRN_TBWU, upper);
86	mtspr(SPRN_TBWL, lower);
87}
88
89extern __inline__ unsigned long get_rtcl(void) {
90	unsigned long rtcl;
91	asm volatile("mfrtcl %0" : "=r" (rtcl));
92	return rtcl;
93}
94
95extern __inline__ unsigned get_native_tbl(void) {
96	if (__USE_RTC())
97		return get_rtcl();
98	else
99	  	return get_tbl();
100}
101
102/* On machines with RTC, this function can only be used safely
103 * after the timestamp and for 1 second. It is only used by gettimeofday
104 * however so it should not matter.
105 */
106extern __inline__ unsigned tb_ticks_since(unsigned tstamp) {
107	if (__USE_RTC()) {
108		int delta = get_rtcl() - tstamp;
109		return delta<0 ? delta + 1000000000 : delta;
110	} else {
111        	return get_tbl() - tstamp;
112	}
113}
114
115
116/* Use mulhwu to scale processor timebase to timeval */
117#define mulhwu(x,y) \
118({unsigned z; asm ("mulhwu %0,%1,%2" : "=r" (z) : "r" (x), "r" (y)); z;})
119
120unsigned mulhwu_scale_factor(unsigned, unsigned);
121#endif /* __ASM_TIME_H__ */
122#endif /* __KERNEL__ */
123