clock.c revision 1.4 
1/*	$NetBSD: clock.c,v 1.4 2002/03/26 00:03:47 kleink Exp $	*/
2
3/*
4 * Copyright (C) 1995, 1996 Wolfgang Solfrank.
5 * Copyright (C) 1995, 1996 TooLs GmbH.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by TooLs GmbH.
19 * 4. The name of TooLs GmbH may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
28 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <lib/libsa/stand.h>
35#include <dev/isa/isareg.h>
36#include <dev/ic/i8253reg.h>
37#include <powerpc/spr.h>
38
39#include "boot.h"
40
41u_long ns_per_tick = NS_PER_TICK;
42
43static inline u_quad_t mftb __P((void));
44static inline void mfrtc __P((u_long *, u_long *));
45
46static inline u_quad_t
47mftb()
48{
49	u_long scratch;
50	u_quad_t tb;
51
52	__asm__ volatile ("1: mftbu %0; mftb %0+1; mftbu %1; cmpw %0,%1; bne 1b"
53	    : "=r"(tb), "=r"(scratch));
54	return (tb);
55}
56
57static inline void
58mfrtc(up, lp)
59	u_long *up;
60	u_long *lp;
61{
62	u_long scratch;
63
64	__asm __volatile ("1: mfspr %0,%3; mfspr %1,%4; mfspr %2,%3;"
65	    "cmpw %0,%2; bne 1b"
66	    : "=r"(*up), "=r"(*lp), "=r"(scratch)
67	    : "n"(SPR_RTCU_R), "n"(SPR_RTCL_R));
68}
69
70/*
71 * Wait for about n microseconds (at least!).
72 */
73void
74delay(n)
75	u_int n;
76{
77	u_quad_t tb;
78	u_long tbh, tbl, scratch;
79	unsigned int cpuvers;
80
81	__asm __volatile ("mfpvr %0" : "=r"(cpuvers));
82	cpuvers >>= 16;
83
84	if (cpuvers == MPC601) {
85		mfrtc(&tbh, &tbl);
86		while (n >= 1000000) {
87			tbh++;
88			n -= 1000000;
89		}
90		tbl += n * 1000;
91		if (tbl >= 1000000000) {
92			tbh++;
93			tbl -= 1000000000;
94		}
95		__asm __volatile ("1: mfspr %0,%3; cmplw %0,%1; blt 1b; bgt 2f;"
96		    "mfspr %0,%4; cmplw %0,%2; blt 1b; 2:"
97		    : "=r"(scratch)
98		    : "r"(tbh), "r"(tbl), "n"(SPR_RTCU_R), "n"(SPR_RTCL_R));
99	} else {
100		tb = mftb();
101		tb += (n * 1000 + ns_per_tick - 1) / ns_per_tick;
102		tbh = tb >> 32;
103		tbl = tb;
104		__asm __volatile ("1: mftbu %0; cmpw %0,%1; blt 1b; bgt 2f;"
105		                  "mftb %0; cmpw %0,%2; blt 1b; 2:"
106		                  : "=r"(scratch)
107		                  : "r"(tbh), "r"(tbl));
108	}
109}
110