hwt.c revision 33f810b2036f13f1b123062a9e5c1794d400ce81 
1/******************************************************************************
2 *
3 *	(C)Copyright 1998,1999 SysKonnect,
4 *	a business unit of Schneider & Koch & Co. Datensysteme GmbH.
5 *
6 *	See the file "skfddi.c" for further information.
7 *
8 *	This program is free software; you can redistribute it and/or modify
9 *	it under the terms of the GNU General Public License as published by
10 *	the Free Software Foundation; either version 2 of the License, or
11 *	(at your option) any later version.
12 *
13 *	The information in this file is provided "AS IS" without warranty.
14 *
15 ******************************************************************************/
16
17/*
18 * Timer Driver for FBI board (timer chip 82C54)
19 */
20
21/*
22 * Modifications:
23 *
24 *	28-Jun-1994 sw	Edit v1.6.
25 *			MCA: Added support for the SK-NET FDDI-FM2 adapter. The
26 *			 following functions have been added(+) or modified(*):
27 *			 hwt_start(*), hwt_stop(*), hwt_restart(*), hwt_read(*)
28 */
29
30#include "h/types.h"
31#include "h/fddi.h"
32#include "h/smc.h"
33
34#ifndef	lint
35static const char ID_sccs[] = "@(#)hwt.c	1.13 97/04/23 (C) SK " ;
36#endif
37
38/*
39 * Prototypes of local functions.
40 */
41/* 28-Jun-1994 sw - Note: hwt_restart() is also used in module 'drvfbi.c'. */
42/*static void hwt_restart() ; */
43
44/************************
45 *
46 *	hwt_start
47 *
48 *	Start hardware timer (clock ticks are 16us).
49 *
50 *	void hwt_start(
51 *		struct s_smc *smc,
52 *		u_long time) ;
53 * In
54 *	smc - A pointer to the SMT Context structure.
55 *
56 *	time - The time in units of 16us to load the timer with.
57 * Out
58 *	Nothing.
59 *
60 ************************/
61#define	HWT_MAX	(65000)
62
63void hwt_start(struct s_smc *smc, u_long time)
64{
65	u_short	cnt ;
66
67	if (time > HWT_MAX)
68		time = HWT_MAX ;
69
70	smc->hw.t_start = time ;
71	smc->hw.t_stop = 0L ;
72
73	cnt = (u_short)time ;
74	/*
75	 * if time < 16 us
76	 *	time = 16 us
77	 */
78	if (!cnt)
79		cnt++ ;
80
81	outpd(ADDR(B2_TI_INI), (u_long) cnt * 200) ;	/* Load timer value. */
82	outpw(ADDR(B2_TI_CRTL), TIM_START) ;		/* Start timer. */
83
84	smc->hw.timer_activ = TRUE ;
85}
86
87/************************
88 *
89 *	hwt_stop
90 *
91 *	Stop hardware timer.
92 *
93 *	void hwt_stop(
94 *		struct s_smc *smc) ;
95 * In
96 *	smc - A pointer to the SMT Context structure.
97 * Out
98 *	Nothing.
99 *
100 ************************/
101void hwt_stop(struct s_smc *smc)
102{
103	outpw(ADDR(B2_TI_CRTL), TIM_STOP) ;
104	outpw(ADDR(B2_TI_CRTL), TIM_CL_IRQ) ;
105
106	smc->hw.timer_activ = FALSE ;
107}
108
109/************************
110 *
111 *	hwt_init
112 *
113 *	Initialize hardware timer.
114 *
115 *	void hwt_init(
116 *		struct s_smc *smc) ;
117 * In
118 *	smc - A pointer to the SMT Context structure.
119 * Out
120 *	Nothing.
121 *
122 ************************/
123void hwt_init(struct s_smc *smc)
124{
125	smc->hw.t_start = 0 ;
126	smc->hw.t_stop	= 0 ;
127	smc->hw.timer_activ = FALSE ;
128
129	hwt_restart(smc) ;
130}
131
132/************************
133 *
134 *	hwt_restart
135 *
136 *	Clear timer interrupt.
137 *
138 *	void hwt_restart(
139 *		struct s_smc *smc) ;
140 * In
141 *	smc - A pointer to the SMT Context structure.
142 * Out
143 *	Nothing.
144 *
145 ************************/
146void hwt_restart(struct s_smc *smc)
147{
148	hwt_stop(smc) ;
149}
150
151/************************
152 *
153 *	hwt_read
154 *
155 *	Stop hardware timer and read time elapsed since last start.
156 *
157 *	u_long hwt_read(smc) ;
158 * In
159 *	smc - A pointer to the SMT Context structure.
160 * Out
161 *	The elapsed time since last start in units of 16us.
162 *
163 ************************/
164u_long hwt_read(struct s_smc *smc)
165{
166	u_short	tr ;
167	u_long	is ;
168
169	if (smc->hw.timer_activ) {
170		hwt_stop(smc) ;
171		tr = (u_short)((inpd(ADDR(B2_TI_VAL))/200) & 0xffff) ;
172
173		is = GET_ISR() ;
174		/* Check if timer expired (or wraparound). */
175		if ((tr > smc->hw.t_start) || (is & IS_TIMINT)) {
176			hwt_restart(smc) ;
177			smc->hw.t_stop = smc->hw.t_start ;
178		}
179		else
180			smc->hw.t_stop = smc->hw.t_start - tr ;
181	}
182	return smc->hw.t_stop;
183}
184
185#ifdef	PCI
186/************************
187 *
188 *	hwt_quick_read
189 *
190 *	Stop hardware timer and read timer value and start the timer again.
191 *
192 *	u_long hwt_read(smc) ;
193 * In
194 *	smc - A pointer to the SMT Context structure.
195 * Out
196 *	current timer value in units of 80ns.
197 *
198 ************************/
199u_long hwt_quick_read(struct s_smc *smc)
200{
201	u_long interval ;
202	u_long time ;
203
204	interval = inpd(ADDR(B2_TI_INI)) ;
205	outpw(ADDR(B2_TI_CRTL), TIM_STOP) ;
206	time = inpd(ADDR(B2_TI_VAL)) ;
207	outpd(ADDR(B2_TI_INI),time) ;
208	outpw(ADDR(B2_TI_CRTL), TIM_START) ;
209	outpd(ADDR(B2_TI_INI),interval) ;
210
211	return time;
212}
213
214/************************
215 *
216 *	hwt_wait_time(smc,start,duration)
217 *
218 *	This function returnes after the amount of time is elapsed
219 *	since the start time.
220 *
221 * para	start		start time
222 *	duration	time to wait
223 *
224 * NOTE: The function will return immediately, if the timer is not
225 *	 started
226 ************************/
227void hwt_wait_time(struct s_smc *smc, u_long start, long int duration)
228{
229	long	diff ;
230	long	interval ;
231	int	wrapped ;
232
233	/*
234	 * check if timer is running
235	 */
236	if (smc->hw.timer_activ == FALSE ||
237		hwt_quick_read(smc) == hwt_quick_read(smc)) {
238		return ;
239	}
240
241	interval = inpd(ADDR(B2_TI_INI)) ;
242	if (interval > duration) {
243		do {
244			diff = (long)(start - hwt_quick_read(smc)) ;
245			if (diff < 0) {
246				diff += interval ;
247			}
248		} while (diff <= duration) ;
249	}
250	else {
251		diff = interval ;
252		wrapped = 0 ;
253		do {
254			if (!wrapped) {
255				if (hwt_quick_read(smc) >= start) {
256					diff += interval ;
257					wrapped = 1 ;
258				}
259			}
260			else {
261				if (hwt_quick_read(smc) < start) {
262					wrapped = 0 ;
263				}
264			}
265		} while (diff <= duration) ;
266	}
267}
268#endif
269
270