xref: /kernel/linux/linux-5.10/drivers/net/fddi/skfp/hwt.c (revision 8c2ecf20)
1// SPDX-License-Identifier: GPL-2.0-or-later
2/******************************************************************************
3 *
4 *	(C)Copyright 1998,1999 SysKonnect,
5 *	a business unit of Schneider & Koch & Co. Datensysteme GmbH.
6 *
7 *	See the file "skfddi.c" for further information.
8 *
9 *	The information in this file is provided "AS IS" without warranty.
10 *
11 ******************************************************************************/
12
13/*
14 * Timer Driver for FBI board (timer chip 82C54)
15 */
16
17/*
18 * Modifications:
19 *
20 *	28-Jun-1994 sw	Edit v1.6.
21 *			MCA: Added support for the SK-NET FDDI-FM2 adapter. The
22 *			 following functions have been added(+) or modified(*):
23 *			 hwt_start(*), hwt_stop(*), hwt_restart(*), hwt_read(*)
24 */
25
26#include "h/types.h"
27#include "h/fddi.h"
28#include "h/smc.h"
29
30#ifndef	lint
31static const char ID_sccs[] = "@(#)hwt.c	1.13 97/04/23 (C) SK " ;
32#endif
33
34/*
35 * Prototypes of local functions.
36 */
37/* 28-Jun-1994 sw - Note: hwt_restart() is also used in module 'drvfbi.c'. */
38/*static void hwt_restart() ; */
39
40/************************
41 *
42 *	hwt_start
43 *
44 *	Start hardware timer (clock ticks are 16us).
45 *
46 *	void hwt_start(
47 *		struct s_smc *smc,
48 *		u_long time) ;
49 * In
50 *	smc - A pointer to the SMT Context structure.
51 *
52 *	time - The time in units of 16us to load the timer with.
53 * Out
54 *	Nothing.
55 *
56 ************************/
57#define	HWT_MAX	(65000)
58
59void hwt_start(struct s_smc *smc, u_long time)
60{
61	u_short	cnt ;
62
63	if (time > HWT_MAX)
64		time = HWT_MAX ;
65
66	smc->hw.t_start = time ;
67	smc->hw.t_stop = 0L ;
68
69	cnt = (u_short)time ;
70	/*
71	 * if time < 16 us
72	 *	time = 16 us
73	 */
74	if (!cnt)
75		cnt++ ;
76
77	outpd(ADDR(B2_TI_INI), (u_long) cnt * 200) ;	/* Load timer value. */
78	outpw(ADDR(B2_TI_CRTL), TIM_START) ;		/* Start timer. */
79
80	smc->hw.timer_activ = TRUE ;
81}
82
83/************************
84 *
85 *	hwt_stop
86 *
87 *	Stop hardware timer.
88 *
89 *	void hwt_stop(
90 *		struct s_smc *smc) ;
91 * In
92 *	smc - A pointer to the SMT Context structure.
93 * Out
94 *	Nothing.
95 *
96 ************************/
97void hwt_stop(struct s_smc *smc)
98{
99	outpw(ADDR(B2_TI_CRTL), TIM_STOP) ;
100	outpw(ADDR(B2_TI_CRTL), TIM_CL_IRQ) ;
101
102	smc->hw.timer_activ = FALSE ;
103}
104
105/************************
106 *
107 *	hwt_init
108 *
109 *	Initialize hardware timer.
110 *
111 *	void hwt_init(
112 *		struct s_smc *smc) ;
113 * In
114 *	smc - A pointer to the SMT Context structure.
115 * Out
116 *	Nothing.
117 *
118 ************************/
119void hwt_init(struct s_smc *smc)
120{
121	smc->hw.t_start = 0 ;
122	smc->hw.t_stop	= 0 ;
123	smc->hw.timer_activ = FALSE ;
124
125	hwt_restart(smc) ;
126}
127
128/************************
129 *
130 *	hwt_restart
131 *
132 *	Clear timer interrupt.
133 *
134 *	void hwt_restart(
135 *		struct s_smc *smc) ;
136 * In
137 *	smc - A pointer to the SMT Context structure.
138 * Out
139 *	Nothing.
140 *
141 ************************/
142void hwt_restart(struct s_smc *smc)
143{
144	hwt_stop(smc) ;
145}
146
147/************************
148 *
149 *	hwt_read
150 *
151 *	Stop hardware timer and read time elapsed since last start.
152 *
153 *	u_long hwt_read(smc) ;
154 * In
155 *	smc - A pointer to the SMT Context structure.
156 * Out
157 *	The elapsed time since last start in units of 16us.
158 *
159 ************************/
160u_long hwt_read(struct s_smc *smc)
161{
162	u_short	tr ;
163	u_long	is ;
164
165	if (smc->hw.timer_activ) {
166		hwt_stop(smc) ;
167		tr = (u_short)((inpd(ADDR(B2_TI_VAL))/200) & 0xffff) ;
168
169		is = GET_ISR() ;
170		/* Check if timer expired (or wraparound). */
171		if ((tr > smc->hw.t_start) || (is & IS_TIMINT)) {
172			hwt_restart(smc) ;
173			smc->hw.t_stop = smc->hw.t_start ;
174		}
175		else
176			smc->hw.t_stop = smc->hw.t_start - tr ;
177	}
178	return smc->hw.t_stop;
179}
180
181#ifdef	PCI
182/************************
183 *
184 *	hwt_quick_read
185 *
186 *	Stop hardware timer and read timer value and start the timer again.
187 *
188 *	u_long hwt_read(smc) ;
189 * In
190 *	smc - A pointer to the SMT Context structure.
191 * Out
192 *	current timer value in units of 80ns.
193 *
194 ************************/
195u_long hwt_quick_read(struct s_smc *smc)
196{
197	u_long interval ;
198	u_long time ;
199
200	interval = inpd(ADDR(B2_TI_INI)) ;
201	outpw(ADDR(B2_TI_CRTL), TIM_STOP) ;
202	time = inpd(ADDR(B2_TI_VAL)) ;
203	outpd(ADDR(B2_TI_INI),time) ;
204	outpw(ADDR(B2_TI_CRTL), TIM_START) ;
205	outpd(ADDR(B2_TI_INI),interval) ;
206
207	return time;
208}
209
210/************************
211 *
212 *	hwt_wait_time(smc,start,duration)
213 *
214 *	This function returnes after the amount of time is elapsed
215 *	since the start time.
216 *
217 * para	start		start time
218 *	duration	time to wait
219 *
220 * NOTE: The function will return immediately, if the timer is not
221 *	 started
222 ************************/
223void hwt_wait_time(struct s_smc *smc, u_long start, long int duration)
224{
225	long	diff ;
226	long	interval ;
227	int	wrapped ;
228
229	/*
230	 * check if timer is running
231	 */
232	if (smc->hw.timer_activ == FALSE ||
233		hwt_quick_read(smc) == hwt_quick_read(smc)) {
234		return ;
235	}
236
237	interval = inpd(ADDR(B2_TI_INI)) ;
238	if (interval > duration) {
239		do {
240			diff = (long)(start - hwt_quick_read(smc)) ;
241			if (diff < 0) {
242				diff += interval ;
243			}
244		} while (diff <= duration) ;
245	}
246	else {
247		diff = interval ;
248		wrapped = 0 ;
249		do {
250			if (!wrapped) {
251				if (hwt_quick_read(smc) >= start) {
252					diff += interval ;
253					wrapped = 1 ;
254				}
255			}
256			else {
257				if (hwt_quick_read(smc) < start) {
258					wrapped = 0 ;
259				}
260			}
261		} while (diff <= duration) ;
262	}
263}
264#endif
265
266