summaryrefslogtreecommitdiff
path: root/examples/timer.c
blob: 8d60fc882689fa4d0765740ad56aebb40024d058 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
/*
 * (C) Copyright 2000
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <commproc.h>
#include <mpc8xx_irq.h>
#include <syscall.h>

#undef	DEBUG

#define	TIMER_PERIOD	1000000		/* 1 second clock */

static void timer_handler (void *arg);


/* Access functions for the Machine State Register */
static __inline__ unsigned long get_msr(void)
{
    unsigned long msr;

    asm volatile("mfmsr %0" : "=r" (msr) :);
    return msr;
}

static __inline__ void set_msr(unsigned long msr)
{
    asm volatile("mtmsr %0" : : "r" (msr));
}

/*
 * Definitions to access the CPM Timer registers
 * See 8xx_immap.h for Internal Memory Map layout,
 * and commproc.h for CPM Interrupt vectors (aka "IRQ"s)
 */

typedef struct tid_8xx_cpmtimer_s {
  int		 cpm_vec;	/* CPM Interrupt Vector for this timer	*/
  ushort	*tgcrp;		/* Pointer to Timer Global Config Reg.	*/
  ushort	*tmrp;		/* Pointer to Timer Mode Register	*/
  ushort	*trrp;		/* Pointer to Timer Reference Register	*/
  ushort	*tcrp;		/* Pointer to Timer Capture Register	*/
  ushort	*tcnp;		/* Pointer to Timer Counter Register	*/
  ushort	*terp;		/* Pointer to Timer Event Register	*/
} tid_8xx_cpmtimer_t;

#ifndef CLOCKRATE
#  define CLOCKRATE 64
#endif

#define	CPMT_CLOCK_DIV		16
#define	CPMT_MAX_PRESCALER	256
#define CPMT_MAX_REFERENCE	65535	/* max. unsigned short */

#define	CPMT_MAX_TICKS		(CPMT_MAX_REFERENCE * CPMT_MAX_PRESCALER)
#define	CPMT_MAX_TICKS_WITH_DIV	(CPMT_MAX_REFERENCE * CPMT_MAX_PRESCALER * CPMT_CLOCK_DIV)
#define	CPMT_MAX_INTERVAL	(CPMT_MAX_TICKS_WITH_DIV / CLOCKRATE)

/* For now: always use max. prescaler value */
#define	CPMT_PRESCALER		(CPMT_MAX_PRESCALER)

/* CPM Timer Event Register Bits */
#define	CPMT_EVENT_CAP		0x0001	/* Capture Event		*/
#define	CPMT_EVENT_REF		0x0002	/* Reference Counter Event	*/

/* CPM Timer Global Config Register */
#define	CPMT_GCR_RST		0x0001	/* Reset  Timer			*/
#define	CPMT_GCR_STP		0x0002	/* Stop   Timer			*/
#define	CPMT_GCR_FRZ		0x0004	/* Freeze Timer			*/
#define	CPMT_GCR_GM_CAS		0x0008	/* Gate Mode / Cascade Timers	*/
#define	CPMT_GCR_MASK		(CPMT_GCR_RST|CPMT_GCR_STP|CPMT_GCR_FRZ|CPMT_GCR_GM_CAS)

/* CPM Timer Mode register */
#define	CPMT_MR_GE		0x0001	/* Gate Enable			*/
#define	CPMT_MR_ICLK_CASC	0x0000	/* Clock internally cascaded	*/
#define	CPMT_MR_ICLK_CLK	0x0002	/* Clock = system clock		*/
#define	CPMT_MR_ICLK_CLKDIV	0x0004	/* Clock = system clock / 16	*/
#define	CPMT_MR_ICLK_TIN	0x0006	/* Clock = TINx signal		*/
#define	CPMT_MR_FRR		0x0008	/* Free Run / Restart		*/
#define	CPMT_MR_ORI		0x0010	/* Out. Reference Interrupt En.	*/
#define	CPMT_MR_OM		0x0020	/* Output Mode			*/
#define	CPMT_MR_CE_DIS		0x0000	/* Capture/Interrupt disabled	*/
#define	CPMT_MR_CE_RISE		0x0040	/* Capt./Interr. on rising  TIN	*/
#define CPMT_MR_CE_FALL		0x0080	/* Capt./Interr. on falling TIN	*/
#define	CPMT_MR_CE_ANY		0x00C0	/* Capt./Interr. on any TIN edge*/



/*
 * which CPM timer to use - index starts at 0 (= timer 1)
 */
#define	TID_TIMER_ID	0	/* use CPM timer 1		*/

void setPeriod (tid_8xx_cpmtimer_t *hwp, ulong interval);

static char *usage = "\n[q, b, e, ?] ";

int timer (int argc, char *argv[])
{
	DECLARE_GLOBAL_DATA_PTR;

	cpmtimer8xx_t *cpmtimerp;	/* Pointer to the CPM Timer structure   */
	tid_8xx_cpmtimer_t hw;
	tid_8xx_cpmtimer_t *hwp = &hw;
	int c;

	/* Pointer to CPM Timer structure */
	cpmtimerp = &((immap_t *) gd->bd->bi_immr_base)->im_cpmtimer;

	mon_printf ("TIMERS=0x%x\n", (unsigned) cpmtimerp);

	/* Initialize pointers depending on which timer we use */
	switch (TID_TIMER_ID) {
	case 0:
		hwp->tmrp = &(cpmtimerp->cpmt_tmr1);
		hwp->trrp = &(cpmtimerp->cpmt_trr1);
		hwp->tcrp = &(cpmtimerp->cpmt_tcr1);
		hwp->tcnp = &(cpmtimerp->cpmt_tcn1);
		hwp->terp = &(cpmtimerp->cpmt_ter1);
		hwp->cpm_vec = CPMVEC_TIMER1;
		break;
	case 1:
		hwp->tmrp = &(cpmtimerp->cpmt_tmr2);
		hwp->trrp = &(cpmtimerp->cpmt_trr2);
		hwp->tcrp = &(cpmtimerp->cpmt_tcr2);
		hwp->tcnp = &(cpmtimerp->cpmt_tcn2);
		hwp->terp = &(cpmtimerp->cpmt_ter2);
		hwp->cpm_vec = CPMVEC_TIMER2;
		break;
	case 2:
		hwp->tmrp = &(cpmtimerp->cpmt_tmr3);
		hwp->trrp = &(cpmtimerp->cpmt_trr3);
		hwp->tcrp = &(cpmtimerp->cpmt_tcr3);
		hwp->tcnp = &(cpmtimerp->cpmt_tcn3);
		hwp->terp = &(cpmtimerp->cpmt_ter3);
		hwp->cpm_vec = CPMVEC_TIMER3;
		break;
	case 3:
		hwp->tmrp = &(cpmtimerp->cpmt_tmr4);
		hwp->trrp = &(cpmtimerp->cpmt_trr4);
		hwp->tcrp = &(cpmtimerp->cpmt_tcr4);
		hwp->tcnp = &(cpmtimerp->cpmt_tcn4);
		hwp->terp = &(cpmtimerp->cpmt_ter4);
		hwp->cpm_vec = CPMVEC_TIMER4;
		break;
	}

	hwp->tgcrp = &cpmtimerp->cpmt_tgcr;

	mon_printf ("Using timer %d\n"
			"tgcr @ 0x%x, tmr @ 0x%x, trr @ 0x%x,"
			" tcr @ 0x%x, tcn @ 0x%x, ter @ 0x%x\n",
			TID_TIMER_ID + 1,
			(unsigned) hwp->tgcrp,
			(unsigned) hwp->tmrp,
			(unsigned) hwp->trrp,
			(unsigned) hwp->tcrp,
			(unsigned) hwp->tcnp,
			(unsigned) hwp->terp
			);

	/* reset timer    */
	*hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);

	/* clear all events */
	*hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF);

	mon_printf (usage);
	while ((c = mon_getc()) != 'q') {
	    if (c == 'b') {

		setPeriod (hwp, TIMER_PERIOD);	/* Set period and start ticking */

		/* Install interrupt handler (enable timer in CIMR) */
		mon_install_hdlr (hwp->cpm_vec, timer_handler, hwp);

		mon_printf ("Enabling timer\n");

		/* enable timer */
		*hwp->tgcrp |= (CPMT_GCR_RST << TID_TIMER_ID);

#ifdef	DEBUG
		mon_printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
			" tcr=0x%x, tcn=0x%x, ter=0x%x\n",
				*hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
				*hwp->tcrp,  *hwp->tcnp, *hwp->terp
				);
#endif
	    } else if (c == 'e') {

		mon_printf ("Stopping timer\n");

		*hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);

#ifdef	DEBUG
		mon_printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
			" tcr=0x%x, tcn=0x%x, ter=0x%x\n",
				*hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
				*hwp->tcrp,  *hwp->tcnp, *hwp->terp
			);
#endif
		/* Uninstall interrupt handler */
		mon_free_hdlr (hwp->cpm_vec);

	    } else if (c == '?') {
#ifdef	DEBUG
		cpic8xx_t *cpm_icp = &((immap_t *) gd->bd->bi_immr_base)->im_cpic;
		sysconf8xx_t *siup = &((immap_t *) gd->bd->bi_immr_base)->im_siu_conf;
#endif

		mon_printf ("\ntgcr=0x%x, tmr=0x%x, trr=0x%x,"
			" tcr=0x%x, tcn=0x%x, ter=0x%x\n",
				*hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
				*hwp->tcrp,  *hwp->tcnp, *hwp->terp
			);
#ifdef	DEBUG
		mon_printf ("SIUMCR=0x%08lx, SYPCR=0x%08lx,"
			" SIMASK=0x%08lx, SIPEND=0x%08lx\n",
				siup->sc_siumcr,
				siup->sc_sypcr,
				siup->sc_simask,
				siup->sc_sipend
			);

		mon_printf ("CIMR=0x%08lx, CICR=0x%08lx, CIPR=0x%08lx\n",
			cpm_icp->cpic_cimr,
			cpm_icp->cpic_cicr,
			cpm_icp->cpic_cipr
			);
#endif
	    } else {
	    	mon_printf ("\nEnter: q - quit, b - start timer, e - stop timer, ? - get status\n");
	    }
	    mon_printf (usage);
	}
	return (0);
}


/* Set period in microseconds and start.
 * Truncate to maximum period if more than this is requested - but warn about it.
 */

void setPeriod (tid_8xx_cpmtimer_t *hwp, ulong interval)
{
	unsigned short prescaler;
	unsigned long ticks;

	mon_printf ("Set interval %ld us\n", interval);

	/* Warn if requesting longer period than possible */
	if (interval > CPMT_MAX_INTERVAL) {
		mon_printf ("Truncate interval %ld to maximum (%d)\n",
				interval, CPMT_MAX_INTERVAL);
		interval = CPMT_MAX_INTERVAL;
	}
	/*
	 * Check if we want to use clock divider:
	 * Since the reference counter can be incremented only in integer steps,
	 * we try to keep it as big as possible to allow the resulting period to be
	 * as precise as possible.
	 */
	/* prescaler, enable interrupt, restart after ref count is reached */
	prescaler = (ushort) ((CPMT_PRESCALER - 1) << 8) |
			CPMT_MR_ORI |
			CPMT_MR_FRR;

	ticks = ((ulong) CLOCKRATE * interval);

	if (ticks > CPMT_MAX_TICKS) {
		ticks /= CPMT_CLOCK_DIV;
		prescaler |= CPMT_MR_ICLK_CLKDIV;	/* use system clock divided by 16 */
	} else {
		prescaler |= CPMT_MR_ICLK_CLK;	/* use system clock without divider */
	}

#ifdef	DEBUG
	mon_printf ("clock/%d, prescale factor %d, reference %ld, ticks %ld\n",
			(ticks > CPMT_MAX_TICKS) ? CPMT_CLOCK_DIV : 1,
			CPMT_PRESCALER,
			(ticks / CPMT_PRESCALER),
			ticks
			);
#endif

	/* set prescaler register */
	*hwp->tmrp = prescaler;

	/* clear timer counter */
	*hwp->tcnp = 0;

	/* set reference register */
	*hwp->trrp = (unsigned short) (ticks / CPMT_PRESCALER);

#ifdef	DEBUG
	mon_printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
		" tcr=0x%x, tcn=0x%x, ter=0x%x\n",
			*hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
			*hwp->tcrp,  *hwp->tcnp, *hwp->terp
		);
#endif
}

/*
 * Handler for CPMVEC_TIMER1 interrupt
 */
static
void timer_handler (void *arg)
{
	tid_8xx_cpmtimer_t *hwp = (tid_8xx_cpmtimer_t *)arg;

	/* printf ("** TER1=%04x ** ", *hwp->terp); */

	/* just for demonstration */
	mon_printf (".");

	/* clear all possible events: Ref. and Cap. */
	*hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF);
}