1/*	$NetBSD: clock.c,v 1.9 2006/04/10 18:40:06 garbled 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#include <powerpc/oea/spr.h>
39
40#include "boot.h"
41
42u_long ns_per_tick = NS_PER_TICK;
43
44static inline u_quad_t mftb(void);
45static inline void mfrtc(u_long *, u_long *);
46
47static inline u_quad_t
48mftb(void)
49{
50	u_long scratch;
51	u_quad_t tb;
52
53	__asm volatile ("1: mftbu %0; mftb %0+1; mftbu %1; cmpw %0,%1; bne 1b"
54	    : "=r"(tb), "=r"(scratch));
55	return (tb);
56}
57
58static inline void
59mfrtc(u_long *up, u_long *lp)
60{
61	u_long scratch;
62
63	__asm volatile ("1: mfspr %0,%3; mfspr %1,%4; mfspr %2,%3;"
64	    "cmpw %0,%2; bne 1b"
65	    : "=r"(*up), "=r"(*lp), "=r"(scratch)
66	    : "n"(SPR_RTCU_R), "n"(SPR_RTCL_R));
67}
68
69/*
70 * Wait for about n microseconds (at least!).
71 */
72void
73delay(u_int n)
74{
75	u_quad_t tb;
76	u_long tbh, tbl, scratch;
77	unsigned int cpuvers;
78
79	__asm volatile ("mfpvr %0" : "=r"(cpuvers));
80	cpuvers >>= 16;
81
82	if (cpuvers == MPC601) {
83		mfrtc(&tbh, &tbl);
84		while (n >= 1000000) {
85			tbh++;
86			n -= 1000000;
87		}
88		tbl += n * 1000;
89		if (tbl >= 1000000000) {
90			tbh++;
91			tbl -= 1000000000;
92		}
93		__asm volatile ("1: mfspr %0,%3; cmplw %0,%1; blt 1b; bgt 2f;"
94		    "mfspr %0,%4; cmplw %0,%2; blt 1b; 2:"
95		    : "=&r"(scratch)
96		    : "r"(tbh), "r"(tbl), "n"(SPR_RTCU_R), "n"(SPR_RTCL_R));
97	} else {
98		tb = mftb();
99		tb += (n * 1000 + ns_per_tick - 1) / ns_per_tick;
100		tbh = tb >> 32;
101		tbl = tb;
102		__asm volatile ("1: mftbu %0; cmpw %0,%1; blt 1b; bgt 2f;"
103		                  "mftb %0; cmpw %0,%2; blt 1b; 2:"
104		                  : "=&r"(scratch)
105		                  : "r"(tbh), "r"(tbl));
106	}
107}
108