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
|
/****************************************************************************
* arch/arm/src/sama5/sam_freerun.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References:
*
* SAMA5D3 Series Data Sheet
* Atmel NoOS sample code.
*
* The Atmel sample code has a BSD compatible license that requires this
* copyright notice:
*
* Copyright (c) 2011, Atmel Corporation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the names NuttX nor Atmel nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>
#include <errno.h>
#include <arch/irq.h>
#include "sam_freerun.h"
#ifdef CONFIG_SAMA5_ONESHOT
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: sam_freerun_handler
*
* Description:
* Timer interrupt callback. When the freerun timer counter overflows,
* this interrupt will occur. We will just increment an overflow count.
*
* Input Parameters:
* handle - The handle that represents the timer state
* arg - An opaque argument provided when the interrupt was registered
* sr - The value of the timer interrupt status register at the time
* that the interrupt occurred.
*
* Returned Value:
* None
*
****************************************************************************/
static void sam_freerun_handler(TC_HANDLE handle, void *arg, uint32_t sr)
{
struct sam_freerun_s *freerun = (struct sam_freerun_s *)arg;
DEBUGASSERT(freerun && freerun->overflow < UINT16_MAX);
freerun->overflow++;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sam_freerun_initialize
*
* Description:
* Initialize the freerun timer wrapper
*
* Input Parameters:
* freerun Caller allocated instance of the freerun state structure
* chan Timer counter channel to be used. See the TC_CHAN*
* definitions in arch/arm/src/sama5/sam_tc.h.
* resolution The required resolution of the timer in units of
* microseconds. NOTE that the range is restricted to the
* range of uint16_t (excluding zero).
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure.
*
****************************************************************************/
int sam_freerun_initialize(struct sam_freerun_s *freerun, int chan,
uint16_t resolution)
{
uint32_t frequency;
uint32_t divisor;
uint32_t cmr;
int ret;
tcvdbg("chan=%d resolution=%d usec\n", chan, resolution);
DEBUGASSERT(freerun && resolution > 0);
/* Get the TC frequency the corresponds to the requested resolution */
frequency = 1000000 / (uint32_t)resolution;
/* The pre-calculate values to use when we start the timer */
ret = sam_tc_divisor(frequency, &divisor, &cmr);
if (ret < 0)
{
tcdbg("ERROR: sam_tc_divisor failed: %d\n", ret);
return ret;
}
tcvdbg("frequency=%lu, divisor=%u, cmr=%08lx\n",
(unsigned long)frequency, (unsigned long)divisor,
(unsigned long)cmr);
/* Allocate the timer/counter and select its mode of operation
*
* CMR_TCCLKS - Returned by sam_tc_divisor
* TC_CMR_CLKI=0 - Not inverted
* TC_CMR_BURST_NONE - Not gated by an external signal
* TC_CMR_CPCSTOP=0 - Don't stop the clock on an RC compare event
* TC_CMR_CPCDIS=0 - Don't disable the clock on an RC compare event
* TC_CMR_EEVTEDG_NONE - No external events (and, hence, no edges
* TC_CMR_EEVT_TIOB - ???? REVISIT
* TC_CMR_ENET=0 - External event trigger disabled
* TC_CMR_WAVSEL_UP - TC_CV is incremented from 0 to 0xffffffff
* TC_CMR_WAVE - Waveform mode
* TC_CMR_ACPA_NONE - RA compare has no effect on TIOA
* TC_CMR_ACPC_NONE - RC compare has no effect on TIOA
* TC_CMR_AEEVT_NONE - No external event effect on TIOA
* TC_CMR_ASWTRG_NONE - No software trigger effect on TIOA
* TC_CMR_BCPB_NONE - RB compare has no effect on TIOB
* TC_CMR_BCPC_NONE - RC compare has no effect on TIOB
* TC_CMR_BEEVT_NONE - No external event effect on TIOB
* TC_CMR_BSWTRG_NONE - No software trigger effect on TIOB
*/
cmr |= (TC_CMR_BURST_NONE | TC_CMR_EEVTEDG_NONE | TC_CMR_EEVT_TIOB |
TC_CMR_WAVSEL_UP | TC_CMR_WAVE | TC_CMR_ACPA_NONE |
TC_CMR_ACPC_NONE | TC_CMR_AEEVT_NONE | TC_CMR_ASWTRG_NONE |
TC_CMR_BCPB_NONE | TC_CMR_BCPC_NONE | TC_CMR_BEEVT_NONE |
TC_CMR_BSWTRG_NONE);
freerun->handle = sam_tc_allocate(chan, cmr);
if (!freerun->handle)
{
tcdbg("ERROR: Failed to allocate timer channel %d\n", chan);
return -EBUSY;
}
/* Initialize the remaining fields in the state structure and return
* success.
*/
freerun->chan = chan;
freerun->running = false;
freerun->resolution = resolution;
/* Set up to receive the callback when the counter overflow occurs */
(void)sam_tc_attach(freerun->handle, sam_freerun_handler, freerun,
TC_INT_COVFS);
/* Start the counter */
sam_tc_start(freerun->handle);
return OK;
}
/****************************************************************************
* Name: sam_freerun_counter
*
* Description:
* Read the counter register of the free-running timer.
*
* Input Parameters:
* freerun Caller allocated instance of the freerun state structure. This
* structure must have been previously initialized via a call to
* sam_freerun_initialize();
* ts The location in which to return the time from the free-running
* timer.
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure.
*
****************************************************************************/
int sam_freerun_counter(struct sam_freerun_s *freerun, struct timespec *ts)
{
uint64_t usec;
uint32_t counter;
uint32_t verify;
uint32_t sr;
uint32_t overflow;
uint32_t sec;
irqstate_t flags;
/* Temporarily disable the overflow counter */
flags = irqsave();
overflow = freerun->overflow;
counter = sam_tc_getcounter(freerun->handle);
sr = sam_tc_getpending(freerun->handle);
verify = sam_tc_getcounter(freerun->handle);
irqrestore(flags);
tcvdbg("counter=%lu (%lu) overflow=%lu, sr=%08lx\n",
(unsigned long)counter, (unsigned long)verify,
(unsigned long)overflow, (unsigned long)sr);
/* If an interrupt was pending before we re-enabled interrupts,
* then our value of overflow needs to be incremented.
*/
if ((sr & TC_INT_COVFS) != 0)
{
/* Increment the overflow count and use the value of the
* guaranteed to be AFTER the overflow occurred.
*/
overflow++;
counter = verify;
tcvdbg("counter=%lu overflow=%lu\n",
(unsigned long)counter, (unsigned long)overflow);
}
/* Convert the whole thing to units of microseconds */
usec = (((uint64_t)overflow << 32) + (uint64_t)counter) *
freerun->resolution;
/* And return the value of the timer */
sec = (uint32_t)(usec / 1000000);
ts->tv_sec = sec;
ts->tv_nsec = (usec - (sec * 1000000)) * 1000;
tcvdbg("usec=%016llx ts=(%lu, %lu)\n",
usec, (unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec);
return OK;
}
/****************************************************************************
* Name: sam_freerun_uninitialize
*
* Description:
* Stop the free-running timer and release all resources that it uses.
*
* Input Parameters:
* freerun Caller allocated instance of the freerun state structure. This
* structure must have been previously initialized via a call to
* sam_freerun_initialize();
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure.
*
****************************************************************************/
int sam_freerun_uninitialize(struct sam_freerun_s *freerun)
{
/* Now we can disable the timer interrupt and disable the timer. */
sam_tc_attach(freerun->handle, NULL, NULL, 0);
sam_tc_stop(freerun->handle);
/* Free the timer */
sam_tc_free(freerun->handle);
return OK;
}
#endif /* CONFIG_SAMA5_ONESHOT */
|