1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Greybus SPI library
4 *
5 * Copyright 2014-2016 Google Inc.
6 * Copyright 2014-2016 Linaro Ltd.
7 */
8
9 #include <linux/bitops.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/greybus.h>
14 #include <linux/spi/spi.h>
15
16 #include "spilib.h"
17
18 struct gb_spilib {
19 struct gb_connection *connection;
20 struct device *parent;
21 struct spi_transfer *first_xfer;
22 struct spi_transfer *last_xfer;
23 struct spilib_ops *ops;
24 u32 rx_xfer_offset;
25 u32 tx_xfer_offset;
26 u32 last_xfer_size;
27 unsigned int op_timeout;
28 u16 mode;
29 u16 flags;
30 u32 bits_per_word_mask;
31 u8 num_chipselect;
32 u32 min_speed_hz;
33 u32 max_speed_hz;
34 };
35
36 #define GB_SPI_STATE_MSG_DONE ((void *)0)
37 #define GB_SPI_STATE_MSG_IDLE ((void *)1)
38 #define GB_SPI_STATE_MSG_RUNNING ((void *)2)
39 #define GB_SPI_STATE_OP_READY ((void *)3)
40 #define GB_SPI_STATE_OP_DONE ((void *)4)
41 #define GB_SPI_STATE_MSG_ERROR ((void *)-1)
42
43 #define XFER_TIMEOUT_TOLERANCE 200
44
get_master_from_spi(struct gb_spilib * spi)45 static struct spi_master *get_master_from_spi(struct gb_spilib *spi)
46 {
47 return gb_connection_get_data(spi->connection);
48 }
49
tx_header_fit_operation(u32 tx_size,u32 count,size_t data_max)50 static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max)
51 {
52 size_t headers_size;
53
54 data_max -= sizeof(struct gb_spi_transfer_request);
55 headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
56
57 return tx_size + headers_size > data_max ? 0 : 1;
58 }
59
calc_rx_xfer_size(u32 rx_size,u32 * tx_xfer_size,u32 len,size_t data_max)60 static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len,
61 size_t data_max)
62 {
63 size_t rx_xfer_size;
64
65 data_max -= sizeof(struct gb_spi_transfer_response);
66
67 if (rx_size + len > data_max)
68 rx_xfer_size = data_max - rx_size;
69 else
70 rx_xfer_size = len;
71
72 /* if this is a write_read, for symmetry read the same as write */
73 if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size)
74 rx_xfer_size = *tx_xfer_size;
75 if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size)
76 *tx_xfer_size = rx_xfer_size;
77
78 return rx_xfer_size;
79 }
80
calc_tx_xfer_size(u32 tx_size,u32 count,size_t len,size_t data_max)81 static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len,
82 size_t data_max)
83 {
84 size_t headers_size;
85
86 data_max -= sizeof(struct gb_spi_transfer_request);
87 headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
88
89 if (tx_size + headers_size + len > data_max)
90 return data_max - (tx_size + sizeof(struct gb_spi_transfer));
91
92 return len;
93 }
94
clean_xfer_state(struct gb_spilib * spi)95 static void clean_xfer_state(struct gb_spilib *spi)
96 {
97 spi->first_xfer = NULL;
98 spi->last_xfer = NULL;
99 spi->rx_xfer_offset = 0;
100 spi->tx_xfer_offset = 0;
101 spi->last_xfer_size = 0;
102 spi->op_timeout = 0;
103 }
104
is_last_xfer_done(struct gb_spilib * spi)105 static bool is_last_xfer_done(struct gb_spilib *spi)
106 {
107 struct spi_transfer *last_xfer = spi->last_xfer;
108
109 if ((spi->tx_xfer_offset + spi->last_xfer_size == last_xfer->len) ||
110 (spi->rx_xfer_offset + spi->last_xfer_size == last_xfer->len))
111 return true;
112
113 return false;
114 }
115
setup_next_xfer(struct gb_spilib * spi,struct spi_message * msg)116 static int setup_next_xfer(struct gb_spilib *spi, struct spi_message *msg)
117 {
118 struct spi_transfer *last_xfer = spi->last_xfer;
119
120 if (msg->state != GB_SPI_STATE_OP_DONE)
121 return 0;
122
123 /*
124 * if we transferred all content of the last transfer, reset values and
125 * check if this was the last transfer in the message
126 */
127 if (is_last_xfer_done(spi)) {
128 spi->tx_xfer_offset = 0;
129 spi->rx_xfer_offset = 0;
130 spi->op_timeout = 0;
131 if (last_xfer == list_last_entry(&msg->transfers,
132 struct spi_transfer,
133 transfer_list))
134 msg->state = GB_SPI_STATE_MSG_DONE;
135 else
136 spi->first_xfer = list_next_entry(last_xfer,
137 transfer_list);
138 return 0;
139 }
140
141 spi->first_xfer = last_xfer;
142 if (last_xfer->tx_buf)
143 spi->tx_xfer_offset += spi->last_xfer_size;
144
145 if (last_xfer->rx_buf)
146 spi->rx_xfer_offset += spi->last_xfer_size;
147
148 return 0;
149 }
150
get_next_xfer(struct spi_transfer * xfer,struct spi_message * msg)151 static struct spi_transfer *get_next_xfer(struct spi_transfer *xfer,
152 struct spi_message *msg)
153 {
154 if (xfer == list_last_entry(&msg->transfers, struct spi_transfer,
155 transfer_list))
156 return NULL;
157
158 return list_next_entry(xfer, transfer_list);
159 }
160
161 /* Routines to transfer data */
gb_spi_operation_create(struct gb_spilib * spi,struct gb_connection * connection,struct spi_message * msg)162 static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
163 struct gb_connection *connection, struct spi_message *msg)
164 {
165 struct gb_spi_transfer_request *request;
166 struct spi_device *dev = msg->spi;
167 struct spi_transfer *xfer;
168 struct gb_spi_transfer *gb_xfer;
169 struct gb_operation *operation;
170 u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size;
171 u32 tx_xfer_size = 0, rx_xfer_size = 0, len;
172 u32 total_len = 0;
173 unsigned int xfer_timeout;
174 size_t data_max;
175 void *tx_data;
176
177 data_max = gb_operation_get_payload_size_max(connection);
178 xfer = spi->first_xfer;
179
180 /* Find number of transfers queued and tx/rx length in the message */
181
182 while (msg->state != GB_SPI_STATE_OP_READY) {
183 msg->state = GB_SPI_STATE_MSG_RUNNING;
184 spi->last_xfer = xfer;
185
186 if (!xfer->tx_buf && !xfer->rx_buf) {
187 dev_err(spi->parent,
188 "bufferless transfer, length %u\n", xfer->len);
189 msg->state = GB_SPI_STATE_MSG_ERROR;
190 return NULL;
191 }
192
193 tx_xfer_size = 0;
194 rx_xfer_size = 0;
195
196 if (xfer->tx_buf) {
197 len = xfer->len - spi->tx_xfer_offset;
198 if (!tx_header_fit_operation(tx_size, count, data_max))
199 break;
200 tx_xfer_size = calc_tx_xfer_size(tx_size, count,
201 len, data_max);
202 spi->last_xfer_size = tx_xfer_size;
203 }
204
205 if (xfer->rx_buf) {
206 len = xfer->len - spi->rx_xfer_offset;
207 rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size,
208 len, data_max);
209 spi->last_xfer_size = rx_xfer_size;
210 }
211
212 tx_size += tx_xfer_size;
213 rx_size += rx_xfer_size;
214
215 total_len += spi->last_xfer_size;
216 count++;
217
218 xfer = get_next_xfer(xfer, msg);
219 if (!xfer || total_len >= data_max)
220 msg->state = GB_SPI_STATE_OP_READY;
221 }
222
223 /*
224 * In addition to space for all message descriptors we need
225 * to have enough to hold all tx data.
226 */
227 request_size = sizeof(*request);
228 request_size += count * sizeof(*gb_xfer);
229 request_size += tx_size;
230
231 /* Response consists only of incoming data */
232 operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
233 request_size, rx_size, GFP_KERNEL);
234 if (!operation)
235 return NULL;
236
237 request = operation->request->payload;
238 request->count = cpu_to_le16(count);
239 request->mode = dev->mode;
240 request->chip_select = spi_get_chipselect(dev, 0);
241
242 gb_xfer = &request->transfers[0];
243 tx_data = gb_xfer + count; /* place tx data after last gb_xfer */
244
245 /* Fill in the transfers array */
246 xfer = spi->first_xfer;
247 while (msg->state != GB_SPI_STATE_OP_DONE) {
248 int xfer_delay;
249
250 if (xfer == spi->last_xfer)
251 xfer_len = spi->last_xfer_size;
252 else
253 xfer_len = xfer->len;
254
255 /* make sure we do not timeout in a slow transfer */
256 xfer_timeout = xfer_len * 8 * MSEC_PER_SEC / xfer->speed_hz;
257 xfer_timeout += GB_OPERATION_TIMEOUT_DEFAULT;
258
259 if (xfer_timeout > spi->op_timeout)
260 spi->op_timeout = xfer_timeout;
261
262 gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz);
263 gb_xfer->len = cpu_to_le32(xfer_len);
264 xfer_delay = spi_delay_to_ns(&xfer->delay, xfer) / 1000;
265 xfer_delay = clamp_t(u16, xfer_delay, 0, U16_MAX);
266 gb_xfer->delay_usecs = cpu_to_le16(xfer_delay);
267 gb_xfer->cs_change = xfer->cs_change;
268 gb_xfer->bits_per_word = xfer->bits_per_word;
269
270 /* Copy tx data */
271 if (xfer->tx_buf) {
272 gb_xfer->xfer_flags |= GB_SPI_XFER_WRITE;
273 memcpy(tx_data, xfer->tx_buf + spi->tx_xfer_offset,
274 xfer_len);
275 tx_data += xfer_len;
276 }
277
278 if (xfer->rx_buf)
279 gb_xfer->xfer_flags |= GB_SPI_XFER_READ;
280
281 if (xfer == spi->last_xfer) {
282 if (!is_last_xfer_done(spi))
283 gb_xfer->xfer_flags |= GB_SPI_XFER_INPROGRESS;
284 msg->state = GB_SPI_STATE_OP_DONE;
285 continue;
286 }
287
288 gb_xfer++;
289 xfer = get_next_xfer(xfer, msg);
290 }
291
292 msg->actual_length += total_len;
293
294 return operation;
295 }
296
gb_spi_decode_response(struct gb_spilib * spi,struct spi_message * msg,struct gb_spi_transfer_response * response)297 static void gb_spi_decode_response(struct gb_spilib *spi,
298 struct spi_message *msg,
299 struct gb_spi_transfer_response *response)
300 {
301 struct spi_transfer *xfer = spi->first_xfer;
302 void *rx_data = response->data;
303 u32 xfer_len;
304
305 while (xfer) {
306 /* Copy rx data */
307 if (xfer->rx_buf) {
308 if (xfer == spi->first_xfer)
309 xfer_len = xfer->len - spi->rx_xfer_offset;
310 else if (xfer == spi->last_xfer)
311 xfer_len = spi->last_xfer_size;
312 else
313 xfer_len = xfer->len;
314
315 memcpy(xfer->rx_buf + spi->rx_xfer_offset, rx_data,
316 xfer_len);
317 rx_data += xfer_len;
318 }
319
320 if (xfer == spi->last_xfer)
321 break;
322
323 xfer = list_next_entry(xfer, transfer_list);
324 }
325 }
326
gb_spi_transfer_one_message(struct spi_master * master,struct spi_message * msg)327 static int gb_spi_transfer_one_message(struct spi_master *master,
328 struct spi_message *msg)
329 {
330 struct gb_spilib *spi = spi_master_get_devdata(master);
331 struct gb_connection *connection = spi->connection;
332 struct gb_spi_transfer_response *response;
333 struct gb_operation *operation;
334 int ret = 0;
335
336 spi->first_xfer = list_first_entry_or_null(&msg->transfers,
337 struct spi_transfer,
338 transfer_list);
339 if (!spi->first_xfer) {
340 ret = -ENOMEM;
341 goto out;
342 }
343
344 msg->state = GB_SPI_STATE_MSG_IDLE;
345
346 while (msg->state != GB_SPI_STATE_MSG_DONE &&
347 msg->state != GB_SPI_STATE_MSG_ERROR) {
348 operation = gb_spi_operation_create(spi, connection, msg);
349 if (!operation) {
350 msg->state = GB_SPI_STATE_MSG_ERROR;
351 ret = -EINVAL;
352 continue;
353 }
354
355 ret = gb_operation_request_send_sync_timeout(operation,
356 spi->op_timeout);
357 if (!ret) {
358 response = operation->response->payload;
359 if (response)
360 gb_spi_decode_response(spi, msg, response);
361 } else {
362 dev_err(spi->parent,
363 "transfer operation failed: %d\n", ret);
364 msg->state = GB_SPI_STATE_MSG_ERROR;
365 }
366
367 gb_operation_put(operation);
368 setup_next_xfer(spi, msg);
369 }
370
371 out:
372 msg->status = ret;
373 clean_xfer_state(spi);
374 spi_finalize_current_message(master);
375
376 return ret;
377 }
378
gb_spi_prepare_transfer_hardware(struct spi_master * master)379 static int gb_spi_prepare_transfer_hardware(struct spi_master *master)
380 {
381 struct gb_spilib *spi = spi_master_get_devdata(master);
382
383 return spi->ops->prepare_transfer_hardware(spi->parent);
384 }
385
gb_spi_unprepare_transfer_hardware(struct spi_master * master)386 static int gb_spi_unprepare_transfer_hardware(struct spi_master *master)
387 {
388 struct gb_spilib *spi = spi_master_get_devdata(master);
389
390 spi->ops->unprepare_transfer_hardware(spi->parent);
391
392 return 0;
393 }
394
gb_spi_setup(struct spi_device * spi)395 static int gb_spi_setup(struct spi_device *spi)
396 {
397 /* Nothing to do for now */
398 return 0;
399 }
400
gb_spi_cleanup(struct spi_device * spi)401 static void gb_spi_cleanup(struct spi_device *spi)
402 {
403 /* Nothing to do for now */
404 }
405
406 /* Routines to get controller information */
407
408 /*
409 * Map Greybus spi mode bits/flags/bpw into Linux ones.
410 * All bits are same for now and so these macro's return same values.
411 */
412 #define gb_spi_mode_map(mode) mode
413 #define gb_spi_flags_map(flags) flags
414
gb_spi_get_master_config(struct gb_spilib * spi)415 static int gb_spi_get_master_config(struct gb_spilib *spi)
416 {
417 struct gb_spi_master_config_response response;
418 u16 mode, flags;
419 int ret;
420
421 ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG,
422 NULL, 0, &response, sizeof(response));
423 if (ret < 0)
424 return ret;
425
426 mode = le16_to_cpu(response.mode);
427 spi->mode = gb_spi_mode_map(mode);
428
429 flags = le16_to_cpu(response.flags);
430 spi->flags = gb_spi_flags_map(flags);
431
432 spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask);
433 spi->num_chipselect = response.num_chipselect;
434
435 spi->min_speed_hz = le32_to_cpu(response.min_speed_hz);
436 spi->max_speed_hz = le32_to_cpu(response.max_speed_hz);
437
438 return 0;
439 }
440
gb_spi_setup_device(struct gb_spilib * spi,u8 cs)441 static int gb_spi_setup_device(struct gb_spilib *spi, u8 cs)
442 {
443 struct spi_master *master = get_master_from_spi(spi);
444 struct gb_spi_device_config_request request;
445 struct gb_spi_device_config_response response;
446 struct spi_board_info spi_board = { {0} };
447 struct spi_device *spidev;
448 int ret;
449 u8 dev_type;
450
451 request.chip_select = cs;
452
453 ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_DEVICE_CONFIG,
454 &request, sizeof(request),
455 &response, sizeof(response));
456 if (ret < 0)
457 return ret;
458
459 dev_type = response.device_type;
460
461 if (dev_type == GB_SPI_SPI_DEV)
462 strscpy(spi_board.modalias, "spidev",
463 sizeof(spi_board.modalias));
464 else if (dev_type == GB_SPI_SPI_NOR)
465 strscpy(spi_board.modalias, "spi-nor",
466 sizeof(spi_board.modalias));
467 else if (dev_type == GB_SPI_SPI_MODALIAS)
468 memcpy(spi_board.modalias, response.name,
469 sizeof(spi_board.modalias));
470 else
471 return -EINVAL;
472
473 spi_board.mode = le16_to_cpu(response.mode);
474 spi_board.bus_num = master->bus_num;
475 spi_board.chip_select = cs;
476 spi_board.max_speed_hz = le32_to_cpu(response.max_speed_hz);
477
478 spidev = spi_new_device(master, &spi_board);
479 if (!spidev)
480 return -EINVAL;
481
482 return 0;
483 }
484
gb_spilib_master_init(struct gb_connection * connection,struct device * dev,struct spilib_ops * ops)485 int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
486 struct spilib_ops *ops)
487 {
488 struct gb_spilib *spi;
489 struct spi_master *master;
490 int ret;
491 u8 i;
492
493 /* Allocate master with space for data */
494 master = spi_alloc_master(dev, sizeof(*spi));
495 if (!master) {
496 dev_err(dev, "cannot alloc SPI master\n");
497 return -ENOMEM;
498 }
499
500 spi = spi_master_get_devdata(master);
501 spi->connection = connection;
502 gb_connection_set_data(connection, master);
503 spi->parent = dev;
504 spi->ops = ops;
505
506 /* get master configuration */
507 ret = gb_spi_get_master_config(spi);
508 if (ret)
509 goto exit_spi_put;
510
511 master->bus_num = -1; /* Allow spi-core to allocate it dynamically */
512 master->num_chipselect = spi->num_chipselect;
513 master->mode_bits = spi->mode;
514 master->flags = spi->flags;
515 master->bits_per_word_mask = spi->bits_per_word_mask;
516
517 /* Attach methods */
518 master->cleanup = gb_spi_cleanup;
519 master->setup = gb_spi_setup;
520 master->transfer_one_message = gb_spi_transfer_one_message;
521
522 if (ops && ops->prepare_transfer_hardware) {
523 master->prepare_transfer_hardware =
524 gb_spi_prepare_transfer_hardware;
525 }
526
527 if (ops && ops->unprepare_transfer_hardware) {
528 master->unprepare_transfer_hardware =
529 gb_spi_unprepare_transfer_hardware;
530 }
531
532 master->auto_runtime_pm = true;
533
534 ret = spi_register_master(master);
535 if (ret < 0)
536 goto exit_spi_put;
537
538 /* now, fetch the devices configuration */
539 for (i = 0; i < spi->num_chipselect; i++) {
540 ret = gb_spi_setup_device(spi, i);
541 if (ret < 0) {
542 dev_err(dev, "failed to allocate spi device %d: %d\n",
543 i, ret);
544 goto exit_spi_unregister;
545 }
546 }
547
548 return 0;
549
550 exit_spi_put:
551 spi_master_put(master);
552
553 return ret;
554
555 exit_spi_unregister:
556 spi_unregister_master(master);
557
558 return ret;
559 }
560 EXPORT_SYMBOL_GPL(gb_spilib_master_init);
561
gb_spilib_master_exit(struct gb_connection * connection)562 void gb_spilib_master_exit(struct gb_connection *connection)
563 {
564 struct spi_master *master = gb_connection_get_data(connection);
565
566 spi_unregister_master(master);
567 }
568 EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
569
570 MODULE_LICENSE("GPL v2");
571