spi_lld.c
13.7 KB
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
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT 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 3 of the License, or
(at your option) any later version.
ChibiOS/RT 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, see <http://www.gnu.org/licenses/>.
---
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes ChibiOS/RT, without being obliged to provide
the source code for any proprietary components. See the file exception.txt
for full details of how and when the exception can be applied.
*/
/**
* @file AT91SAM7/spi_lld.c
* @brief AT91SAM7 low level SPI driver code.
*
* @addtogroup SPI
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_SPI || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
#if AT91SAM7_SPI_USE_SPI0 || defined(__DOXYGEN__)
/** @brief SPI1 driver identifier.*/
SPIDriver SPID1;
#endif
#if AT91SAM7_SPI_USE_SPI1 || defined(__DOXYGEN__)
/** @brief SPI2 driver identifier.*/
SPIDriver SPID2;
#endif
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
/**
* @brief Idle line value.
* @details This thing's DMA apparently does not allow to *not* increment
* the memory pointer so a buffer filled with ones is required
* somewhere.
* @note This buffer size also limits the maximum transfer size, 512B,
* for @p spiReceive() and @p spiIgnore(). @p spiSend() and
* @p spiExchange are not affected.
*/
static const uint16_t idle_buf[] = {
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF
};
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/**
* @brief Initializes a SPI device.
*/
static void spi_init(AT91PS_SPI spi) {
/* Software reset must be written twice (errata for revision B parts).*/
spi->SPI_CR = AT91C_SPI_SWRST;
spi->SPI_CR = AT91C_SPI_SWRST;
spi->SPI_RCR = 0;
spi->SPI_RNCR = 0;
spi->SPI_TCR = 0;
spi->SPI_TNCR = 0;
spi->SPI_PTCR = AT91C_PDC_RXTDIS | AT91C_PDC_TXTDIS;
spi->SPI_MR = AT91C_SPI_MSTR | AT91C_SPI_MODFDIS;
}
#if defined(__GNUC__)
__attribute__((noinline))
#endif
/**
* @brief Shared interrupt handling code.
*
* @param[in] spip pointer to the @p SPIDriver object
*/
static void spi_lld_serve_interrupt(SPIDriver *spip) {
uint32_t sr = spip->spi->SPI_SR;
if ((sr & AT91C_SPI_ENDRX) != 0) {
(void)spip->spi->SPI_RDR; /* Clears eventual overflow.*/
spip->spi->SPI_PTCR = AT91C_PDC_RXTDIS |
AT91C_PDC_TXTDIS; /* PDC disabled. */
spip->spi->SPI_IDR = AT91C_SPI_ENDRX; /* Interrupt disabled. */
spip->spi->SPI_CR = AT91C_SPI_SPIDIS; /* SPI disabled. */
/* Portable SPI ISR code defined in the high level driver, note, it is
a macro.*/
_spi_isr_code(spip);
}
}
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
#if AT91SAM7_SPI_USE_SPI0 || defined(__DOXYGEN__)
/**
* @brief SPI0 interrupt handler.
*
* @isr
*/
CH_IRQ_HANDLER(SPI0IrqHandler) {
CH_IRQ_PROLOGUE();
spi_lld_serve_interrupt(&SPID1);
AT91C_BASE_AIC->AIC_EOICR = 0;
CH_IRQ_EPILOGUE();
}
#endif
#if AT91SAM7_SPI_USE_SPI1 || defined(__DOXYGEN__)
/**
* @brief SPI1 interrupt handler.
*
* @isr
*/
CH_IRQ_HANDLER(SPI1IrqHandler) {
CH_IRQ_PROLOGUE();
spi_lld_serve_interrupt(&SPID2);
AT91C_BASE_AIC->AIC_EOICR = 0;
CH_IRQ_EPILOGUE();
}
#endif
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level SPI driver initialization.
*
* @notapi
*/
void spi_lld_init(void) {
#if AT91SAM7_SPI_USE_SPI0
spiObjectInit(&SPID1);
SPID1.spi = AT91C_BASE_SPI0;
spi_init(AT91C_BASE_SPI0);
AT91C_BASE_PIOA->PIO_PDR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
AT91C_BASE_PIOA->PIO_ASR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
AT91C_BASE_PIOA->PIO_PPUDR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
AIC_ConfigureIT(AT91C_ID_SPI0,
AT91C_AIC_SRCTYPE_HIGH_LEVEL | AT91SAM7_SPI0_PRIORITY,
SPI0IrqHandler);
#endif
#if AT91SAM7_SPI_USE_SPI1
spiObjectInit(&SPID2);
SPID2.spi = AT91C_BASE_SPI1;
spi_init(AT91C_BASE_SPI1);
AT91C_BASE_PIOA->PIO_PDR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
AT91C_BASE_PIOA->PIO_BSR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
AT91C_BASE_PIOA->PIO_PPUDR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
AIC_ConfigureIT(AT91C_ID_SPI1,
AT91C_AIC_SRCTYPE_HIGH_LEVEL | AT91SAM7_SPI1_PRIORITY,
SPI1IrqHandler);
#endif
}
/**
* @brief Configures and activates the SPI peripheral.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
void spi_lld_start(SPIDriver *spip) {
if (spip->state == SPI_STOP) {
#if AT91SAM7_SPI_USE_SPI0
if (&SPID1 == spip) {
/* Clock activation.*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_SPI0);
/* Enables associated interrupt vector.*/
AIC_EnableIT(AT91C_ID_SPI0);
}
#endif
#if AT91SAM7_SPI_USE_SPI1
if (&SPID2 == spip) {
/* Clock activation.*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_SPI1);
/* Enables associated interrupt vector.*/
AIC_EnableIT(AT91C_ID_SPI1);
}
#endif
}
/* Configuration.*/
spip->spi->SPI_CSR[0] = spip->config->csr;
}
/**
* @brief Deactivates the SPI peripheral.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
void spi_lld_stop(SPIDriver *spip) {
if (spip->state != SPI_STOP) {
#if AT91SAM7_SPI_USE_SPI0
if (&SPID1 == spip) {
AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_SPI0);
AIC_DisableIT(AT91C_ID_SPI0);
}
#endif
#if AT91SAM7_SPI_USE_SPI1
if (&SPID1 == spip) {
AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_SPI1);
AIC_DisableIT(AT91C_ID_SPI0);
}
#endif
}
}
/**
* @brief Asserts the slave select signal and prepares for transfers.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
void spi_lld_select(SPIDriver *spip) {
palClearPad(spip->config->ssport, spip->config->sspad);
}
/**
* @brief Deasserts the slave select signal.
* @details The previously selected peripheral is unselected.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
void spi_lld_unselect(SPIDriver *spip) {
palSetPad(spip->config->ssport, spip->config->sspad);
}
/**
* @brief Ignores data on the SPI bus.
* @details This function transmits a series of idle words on the SPI bus and
* ignores the received data. This function can be invoked even
* when a slave select signal has not been yet asserted.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to be ignored
*
* @notapi
*/
void spi_lld_ignore(SPIDriver *spip, size_t n) {
spip->spi->SPI_TCR = n;
spip->spi->SPI_RCR = n;
spip->spi->SPI_TPR = (AT91_REG)idle_buf;
spip->spi->SPI_RPR = (AT91_REG)idle_buf;
spip->spi->SPI_IER = AT91C_SPI_ENDRX;
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}
/**
* @brief Exchanges data on the SPI bus.
* @details This function performs a simultaneous transmit/receive operation.
* @note The buffers are organized as uint8_t arrays.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to be exchanged
* @param[in] txbuf the pointer to the transmit buffer
* @param[out] rxbuf the pointer to the receive buffer
*
* @notapi
*/
void spi_lld_exchange(SPIDriver *spip, size_t n,
const void *txbuf, void *rxbuf) {
spip->spi->SPI_TCR = n;
spip->spi->SPI_RCR = n;
spip->spi->SPI_TPR = (AT91_REG)txbuf;
spip->spi->SPI_RPR = (AT91_REG)rxbuf;
spip->spi->SPI_IER = AT91C_SPI_ENDRX;
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}
/**
* @brief Sends data over the SPI bus.
* @note The buffers are organized as uint8_t arrays.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to send
* @param[in] txbuf the pointer to the transmit buffer
*
* @notapi
*/
void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) {
spip->spi->SPI_TCR = n;
spip->spi->SPI_RCR = n;
spip->spi->SPI_TPR = (AT91_REG)txbuf;
spip->spi->SPI_RPR = (AT91_REG)idle_buf;
spip->spi->SPI_IER = AT91C_SPI_ENDRX;
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}
/**
* @brief Receives data from the SPI bus.
* @note The buffers are organized as uint8_t arrays.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to receive
* @param[out] rxbuf the pointer to the receive buffer
*
* @notapi
*/
void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {
spip->spi->SPI_TCR = n;
spip->spi->SPI_RCR = n;
spip->spi->SPI_TPR = (AT91_REG)idle_buf;
spip->spi->SPI_RPR = (AT91_REG)rxbuf;
spip->spi->SPI_IER = AT91C_SPI_ENDRX;
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}
/**
* @brief Exchanges one frame using a polled wait.
* @details This synchronous function exchanges one frame using a polled
* synchronization method. This function is useful when exchanging
* small amount of data on high speed channels, usually in this
* situation is much more efficient just wait for completion using
* polling than suspending the thread waiting for an interrupt.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] frame the data frame to send over the SPI bus
* @return The received data frame from the SPI bus.
*/
uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) {
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_TDR = frame;
while ((spip->spi->SPI_SR & AT91C_SPI_RDRF) == 0)
;
return spip->spi->SPI_RDR;
}
#endif /* HAL_USE_SPI */
/** @} */