1 /*
2 * Greybus SPI library
3 *
4 * Copyright 2014-2016 Google Inc.
5 * Copyright 2014-2016 Linaro Ltd.
6 *
7 * Released under the GPLv2 only.
8 */
9
10 #include <linux/bitops.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/spi/spi.h>
15
16 #include "greybus.h"
17 #include "spilib.h"
18
19 struct gb_spilib {
20 struct gb_connection *connection;
21 struct device *parent;
22 struct spi_transfer *first_xfer;
23 struct spi_transfer *last_xfer;
24 struct spilib_ops *ops;
25 u32 rx_xfer_offset;
26 u32 tx_xfer_offset;
27 u32 last_xfer_size;
28 unsigned int op_timeout;
29 u16 mode;
30 u16 flags;
31 u32 bits_per_word_mask;
32 u8 num_chipselect;
33 u32 min_speed_hz;
34 u32 max_speed_hz;
35 };
36
37 #define GB_SPI_STATE_MSG_DONE ((void *)0)
38 #define GB_SPI_STATE_MSG_IDLE ((void *)1)
39 #define GB_SPI_STATE_MSG_RUNNING ((void *)2)
40 #define GB_SPI_STATE_OP_READY ((void *)3)
41 #define GB_SPI_STATE_OP_DONE ((void *)4)
42 #define GB_SPI_STATE_MSG_ERROR ((void *)-1)
43
44 #define XFER_TIMEOUT_TOLERANCE 200
45
get_master_from_spi(struct gb_spilib * spi)46 static struct spi_master *get_master_from_spi(struct gb_spilib *spi)
47 {
48 return gb_connection_get_data(spi->connection);
49 }
50
tx_header_fit_operation(u32 tx_size,u32 count,size_t data_max)51 static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max)
52 {
53 size_t headers_size;
54
55 data_max -= sizeof(struct gb_spi_transfer_request);
56 headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
57
58 return tx_size + headers_size > data_max ? 0 : 1;
59 }
60
calc_rx_xfer_size(u32 rx_size,u32 * tx_xfer_size,u32 len,size_t data_max)61 static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len,
62 size_t data_max)
63 {
64 size_t rx_xfer_size;
65
66 data_max -= sizeof(struct gb_spi_transfer_response);
67
68 if (rx_size + len > data_max)
69 rx_xfer_size = data_max - rx_size;
70 else
71 rx_xfer_size = len;
72
73 /* if this is a write_read, for symmetry read the same as write */
74 if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size)
75 rx_xfer_size = *tx_xfer_size;
76 if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size)
77 *tx_xfer_size = rx_xfer_size;
78
79 return rx_xfer_size;
80 }
81
calc_tx_xfer_size(u32 tx_size,u32 count,size_t len,size_t data_max)82 static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len,
83 size_t data_max)
84 {
85 size_t headers_size;
86
87 data_max -= sizeof(struct gb_spi_transfer_request);
88 headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
89
90 if (tx_size + headers_size + len > data_max)
91 return data_max - (tx_size + sizeof(struct gb_spi_transfer));
92
93 return len;
94 }
95
clean_xfer_state(struct gb_spilib * spi)96 static void clean_xfer_state(struct gb_spilib *spi)
97 {
98 spi->first_xfer = NULL;
99 spi->last_xfer = NULL;
100 spi->rx_xfer_offset = 0;
101 spi->tx_xfer_offset = 0;
102 spi->last_xfer_size = 0;
103 spi->op_timeout = 0;
104 }
105
is_last_xfer_done(struct gb_spilib * spi)106 static bool is_last_xfer_done(struct gb_spilib *spi)
107 {
108 struct spi_transfer *last_xfer = spi->last_xfer;
109
110 if ((spi->tx_xfer_offset + spi->last_xfer_size == last_xfer->len) ||
111 (spi->rx_xfer_offset + spi->last_xfer_size == last_xfer->len))
112 return true;
113
114 return false;
115 }
116
setup_next_xfer(struct gb_spilib * spi,struct spi_message * msg)117 static int setup_next_xfer(struct gb_spilib *spi, struct spi_message *msg)
118 {
119 struct spi_transfer *last_xfer = spi->last_xfer;
120
121 if (msg->state != GB_SPI_STATE_OP_DONE)
122 return 0;
123
124 /*
125 * if we transferred all content of the last transfer, reset values and
126 * check if this was the last transfer in the message
127 */
128 if (is_last_xfer_done(spi)) {
129 spi->tx_xfer_offset = 0;
130 spi->rx_xfer_offset = 0;
131 spi->op_timeout = 0;
132 if (last_xfer == list_last_entry(&msg->transfers,
133 struct spi_transfer,
134 transfer_list))
135 msg->state = GB_SPI_STATE_MSG_DONE;
136 else
137 spi->first_xfer = list_next_entry(last_xfer,
138 transfer_list);
139 return 0;
140 }
141
142 spi->first_xfer = last_xfer;
143 if (last_xfer->tx_buf)
144 spi->tx_xfer_offset += spi->last_xfer_size;
145
146 if (last_xfer->rx_buf)
147 spi->rx_xfer_offset += spi->last_xfer_size;
148
149 return 0;
150 }
151
get_next_xfer(struct spi_transfer * xfer,struct spi_message * msg)152 static struct spi_transfer *get_next_xfer(struct spi_transfer *xfer,
153 struct spi_message *msg)
154 {
155 if (xfer == list_last_entry(&msg->transfers, struct spi_transfer,
156 transfer_list))
157 return NULL;
158
159 return list_next_entry(xfer, transfer_list);
160 }
161
162 /* Routines to transfer data */
gb_spi_operation_create(struct gb_spilib * spi,struct gb_connection * connection,struct spi_message * msg)163 static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
164 struct gb_connection *connection, struct spi_message *msg)
165 {
166 struct gb_spi_transfer_request *request;
167 struct spi_device *dev = msg->spi;
168 struct spi_transfer *xfer;
169 struct gb_spi_transfer *gb_xfer;
170 struct gb_operation *operation;
171 u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size;
172 u32 tx_xfer_size = 0, rx_xfer_size = 0, len;
173 u32 total_len = 0;
174 unsigned int xfer_timeout;
175 size_t data_max;
176 void *tx_data;
177
178 data_max = gb_operation_get_payload_size_max(connection);
179 xfer = spi->first_xfer;
180
181 /* Find number of transfers queued and tx/rx length in the message */
182
183 while (msg->state != GB_SPI_STATE_OP_READY) {
184 msg->state = GB_SPI_STATE_MSG_RUNNING;
185 spi->last_xfer = xfer;
186
187 if (!xfer->tx_buf && !xfer->rx_buf) {
188 dev_err(spi->parent,
189 "bufferless transfer, length %u\n", xfer->len);
190 msg->state = GB_SPI_STATE_MSG_ERROR;
191 return NULL;
192 }
193
194 tx_xfer_size = 0;
195 rx_xfer_size = 0;
196
197 if (xfer->tx_buf) {
198 len = xfer->len - spi->tx_xfer_offset;
199 if (!tx_header_fit_operation(tx_size, count, data_max))
200 break;
201 tx_xfer_size = calc_tx_xfer_size(tx_size, count,
202 len, data_max);
203 spi->last_xfer_size = tx_xfer_size;
204 }
205
206 if (xfer->rx_buf) {
207 len = xfer->len - spi->rx_xfer_offset;
208 rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size,
209 len, data_max);
210 spi->last_xfer_size = rx_xfer_size;
211 }
212
213 tx_size += tx_xfer_size;
214 rx_size += rx_xfer_size;
215
216 total_len += spi->last_xfer_size;
217 count++;
218
219 xfer = get_next_xfer(xfer, msg);
220 if (!xfer || total_len >= data_max)
221 msg->state = GB_SPI_STATE_OP_READY;
222 }
223
224 /*
225 * In addition to space for all message descriptors we need
226 * to have enough to hold all tx data.
227 */
228 request_size = sizeof(*request);
229 request_size += count * sizeof(*gb_xfer);
230 request_size += tx_size;
231
232 /* Response consists only of incoming data */
233 operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
234 request_size, rx_size, GFP_KERNEL);
235 if (!operation)
236 return NULL;
237
238 request = operation->request->payload;
239 request->count = cpu_to_le16(count);
240 request->mode = dev->mode;
241 request->chip_select = dev->chip_select;
242
243 gb_xfer = &request->transfers[0];
244 tx_data = gb_xfer + count; /* place tx data after last gb_xfer */
245
246 /* Fill in the transfers array */
247 xfer = spi->first_xfer;
248 while (msg->state != GB_SPI_STATE_OP_DONE) {
249 if (xfer == spi->last_xfer)
250 xfer_len = spi->last_xfer_size;
251 else
252 xfer_len = xfer->len;
253
254 /* make sure we do not timeout in a slow transfer */
255 xfer_timeout = xfer_len * 8 * MSEC_PER_SEC / xfer->speed_hz;
256 xfer_timeout += GB_OPERATION_TIMEOUT_DEFAULT;
257
258 if (xfer_timeout > spi->op_timeout)
259 spi->op_timeout = xfer_timeout;
260
261 gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz);
262 gb_xfer->len = cpu_to_le32(xfer_len);
263 gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs);
264 gb_xfer->cs_change = xfer->cs_change;
265 gb_xfer->bits_per_word = xfer->bits_per_word;
266
267 /* Copy tx data */
268 if (xfer->tx_buf) {
269 gb_xfer->xfer_flags |= GB_SPI_XFER_WRITE;
270 memcpy(tx_data, xfer->tx_buf + spi->tx_xfer_offset,
271 xfer_len);
272 tx_data += xfer_len;
273 }
274
275 if (xfer->rx_buf)
276 gb_xfer->xfer_flags |= GB_SPI_XFER_READ;
277
278 if (xfer == spi->last_xfer) {
279 if (!is_last_xfer_done(spi))
280 gb_xfer->xfer_flags |= GB_SPI_XFER_INPROGRESS;
281 msg->state = GB_SPI_STATE_OP_DONE;
282 continue;
283 }
284
285 gb_xfer++;
286 xfer = get_next_xfer(xfer, msg);
287 }
288
289 msg->actual_length += total_len;
290
291 return operation;
292 }
293
gb_spi_decode_response(struct gb_spilib * spi,struct spi_message * msg,struct gb_spi_transfer_response * response)294 static void gb_spi_decode_response(struct gb_spilib *spi,
295 struct spi_message *msg,
296 struct gb_spi_transfer_response *response)
297 {
298 struct spi_transfer *xfer = spi->first_xfer;
299 void *rx_data = response->data;
300 u32 xfer_len;
301
302 while (xfer) {
303 /* Copy rx data */
304 if (xfer->rx_buf) {
305 if (xfer == spi->first_xfer)
306 xfer_len = xfer->len - spi->rx_xfer_offset;
307 else if (xfer == spi->last_xfer)
308 xfer_len = spi->last_xfer_size;
309 else
310 xfer_len = xfer->len;
311
312 memcpy(xfer->rx_buf + spi->rx_xfer_offset, rx_data,
313 xfer_len);
314 rx_data += xfer_len;
315 }
316
317 if (xfer == spi->last_xfer)
318 break;
319
320 xfer = list_next_entry(xfer, transfer_list);
321 }
322 }
323
gb_spi_transfer_one_message(struct spi_master * master,struct spi_message * msg)324 static int gb_spi_transfer_one_message(struct spi_master *master,
325 struct spi_message *msg)
326 {
327 struct gb_spilib *spi = spi_master_get_devdata(master);
328 struct gb_connection *connection = spi->connection;
329 struct gb_spi_transfer_response *response;
330 struct gb_operation *operation;
331 int ret = 0;
332
333 spi->first_xfer = list_first_entry_or_null(&msg->transfers,
334 struct spi_transfer,
335 transfer_list);
336 if (!spi->first_xfer) {
337 ret = -ENOMEM;
338 goto out;
339 }
340
341 msg->state = GB_SPI_STATE_MSG_IDLE;
342
343 while (msg->state != GB_SPI_STATE_MSG_DONE &&
344 msg->state != GB_SPI_STATE_MSG_ERROR) {
345 operation = gb_spi_operation_create(spi, connection, msg);
346 if (!operation) {
347 msg->state = GB_SPI_STATE_MSG_ERROR;
348 ret = -EINVAL;
349 continue;
350 }
351
352 ret = gb_operation_request_send_sync_timeout(operation,
353 spi->op_timeout);
354 if (!ret) {
355 response = operation->response->payload;
356 if (response)
357 gb_spi_decode_response(spi, msg, response);
358 } else {
359 dev_err(spi->parent,
360 "transfer operation failed: %d\n", ret);
361 msg->state = GB_SPI_STATE_MSG_ERROR;
362 }
363
364 gb_operation_put(operation);
365 setup_next_xfer(spi, msg);
366 }
367
368 out:
369 msg->status = ret;
370 clean_xfer_state(spi);
371 spi_finalize_current_message(master);
372
373 return ret;
374 }
375
gb_spi_prepare_transfer_hardware(struct spi_master * master)376 static int gb_spi_prepare_transfer_hardware(struct spi_master *master)
377 {
378 struct gb_spilib *spi = spi_master_get_devdata(master);
379
380 return spi->ops->prepare_transfer_hardware(spi->parent);
381 }
382
gb_spi_unprepare_transfer_hardware(struct spi_master * master)383 static int gb_spi_unprepare_transfer_hardware(struct spi_master *master)
384 {
385 struct gb_spilib *spi = spi_master_get_devdata(master);
386
387 spi->ops->unprepare_transfer_hardware(spi->parent);
388
389 return 0;
390 }
391
gb_spi_setup(struct spi_device * spi)392 static int gb_spi_setup(struct spi_device *spi)
393 {
394 /* Nothing to do for now */
395 return 0;
396 }
397
gb_spi_cleanup(struct spi_device * spi)398 static void gb_spi_cleanup(struct spi_device *spi)
399 {
400 /* Nothing to do for now */
401 }
402
403 /* Routines to get controller information */
404
405 /*
406 * Map Greybus spi mode bits/flags/bpw into Linux ones.
407 * All bits are same for now and so these macro's return same values.
408 */
409 #define gb_spi_mode_map(mode) mode
410 #define gb_spi_flags_map(flags) flags
411
gb_spi_get_master_config(struct gb_spilib * spi)412 static int gb_spi_get_master_config(struct gb_spilib *spi)
413 {
414 struct gb_spi_master_config_response response;
415 u16 mode, flags;
416 int ret;
417
418 ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG,
419 NULL, 0, &response, sizeof(response));
420 if (ret < 0)
421 return ret;
422
423 mode = le16_to_cpu(response.mode);
424 spi->mode = gb_spi_mode_map(mode);
425
426 flags = le16_to_cpu(response.flags);
427 spi->flags = gb_spi_flags_map(flags);
428
429 spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask);
430 spi->num_chipselect = response.num_chipselect;
431
432 spi->min_speed_hz = le32_to_cpu(response.min_speed_hz);
433 spi->max_speed_hz = le32_to_cpu(response.max_speed_hz);
434
435 return 0;
436 }
437
gb_spi_setup_device(struct gb_spilib * spi,u8 cs)438 static int gb_spi_setup_device(struct gb_spilib *spi, u8 cs)
439 {
440 struct spi_master *master = get_master_from_spi(spi);
441 struct gb_spi_device_config_request request;
442 struct gb_spi_device_config_response response;
443 struct spi_board_info spi_board = { {0} };
444 struct spi_device *spidev;
445 int ret;
446 u8 dev_type;
447
448 request.chip_select = cs;
449
450 ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_DEVICE_CONFIG,
451 &request, sizeof(request),
452 &response, sizeof(response));
453 if (ret < 0)
454 return ret;
455
456 dev_type = response.device_type;
457
458 if (dev_type == GB_SPI_SPI_DEV)
459 strlcpy(spi_board.modalias, "spidev",
460 sizeof(spi_board.modalias));
461 else if (dev_type == GB_SPI_SPI_NOR)
462 strlcpy(spi_board.modalias, "spi-nor",
463 sizeof(spi_board.modalias));
464 else if (dev_type == GB_SPI_SPI_MODALIAS)
465 memcpy(spi_board.modalias, response.name,
466 sizeof(spi_board.modalias));
467 else
468 return -EINVAL;
469
470 spi_board.mode = le16_to_cpu(response.mode);
471 spi_board.bus_num = master->bus_num;
472 spi_board.chip_select = cs;
473 spi_board.max_speed_hz = le32_to_cpu(response.max_speed_hz);
474
475 spidev = spi_new_device(master, &spi_board);
476 if (!spidev)
477 return -EINVAL;
478
479 return 0;
480 }
481
gb_spilib_master_init(struct gb_connection * connection,struct device * dev,struct spilib_ops * ops)482 int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
483 struct spilib_ops *ops)
484 {
485 struct gb_spilib *spi;
486 struct spi_master *master;
487 int ret;
488 u8 i;
489
490 /* Allocate master with space for data */
491 master = spi_alloc_master(dev, sizeof(*spi));
492 if (!master) {
493 dev_err(dev, "cannot alloc SPI master\n");
494 return -ENOMEM;
495 }
496
497 spi = spi_master_get_devdata(master);
498 spi->connection = connection;
499 gb_connection_set_data(connection, master);
500 spi->parent = dev;
501 spi->ops = ops;
502
503 /* get master configuration */
504 ret = gb_spi_get_master_config(spi);
505 if (ret)
506 goto exit_spi_put;
507
508 master->bus_num = -1; /* Allow spi-core to allocate it dynamically */
509 master->num_chipselect = spi->num_chipselect;
510 master->mode_bits = spi->mode;
511 master->flags = spi->flags;
512 master->bits_per_word_mask = spi->bits_per_word_mask;
513
514 /* Attach methods */
515 master->cleanup = gb_spi_cleanup;
516 master->setup = gb_spi_setup;
517 master->transfer_one_message = gb_spi_transfer_one_message;
518
519 if (ops && ops->prepare_transfer_hardware) {
520 master->prepare_transfer_hardware =
521 gb_spi_prepare_transfer_hardware;
522 }
523
524 if (ops && ops->unprepare_transfer_hardware) {
525 master->unprepare_transfer_hardware =
526 gb_spi_unprepare_transfer_hardware;
527 }
528
529 master->auto_runtime_pm = true;
530
531 ret = spi_register_master(master);
532 if (ret < 0)
533 goto exit_spi_put;
534
535 /* now, fetch the devices configuration */
536 for (i = 0; i < spi->num_chipselect; i++) {
537 ret = gb_spi_setup_device(spi, i);
538 if (ret < 0) {
539 dev_err(dev, "failed to allocate spi device %d: %d\n",
540 i, ret);
541 goto exit_spi_unregister;
542 }
543 }
544
545 return 0;
546
547 exit_spi_put:
548 spi_master_put(master);
549
550 return ret;
551
552 exit_spi_unregister:
553 spi_unregister_master(master);
554
555 return ret;
556 }
557 EXPORT_SYMBOL_GPL(gb_spilib_master_init);
558
gb_spilib_master_exit(struct gb_connection * connection)559 void gb_spilib_master_exit(struct gb_connection *connection)
560 {
561 struct spi_master *master = gb_connection_get_data(connection);
562
563 spi_unregister_master(master);
564 }
565 EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
566
567 MODULE_LICENSE("GPL v2");
568