blob: 2060d1483043d8ee52dba6e4a65d20ba18a2b97a [file] [log] [blame]
Simon Glassa17d94f2013-02-25 14:08:39 -08001/*
2 * ChromeOS EC multi-function device (SPI)
3 *
4 * Copyright (C) 2012 Google, Inc
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16#include <linux/delay.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/mfd/cros_ec.h>
20#include <linux/mfd/cros_ec_commands.h>
Rhyland Klein01e73c82013-12-09 12:36:09 +010021#include <linux/of.h>
Simon Glassa17d94f2013-02-25 14:08:39 -080022#include <linux/platform_device.h>
23#include <linux/slab.h>
24#include <linux/spi/spi.h>
25
26
27/* The header byte, which follows the preamble */
28#define EC_MSG_HEADER 0xec
29
30/*
31 * Number of EC preamble bytes we read at a time. Since it takes
32 * about 400-500us for the EC to respond there is not a lot of
33 * point in tuning this. If the EC could respond faster then
34 * we could increase this so that might expect the preamble and
35 * message to occur in a single transaction. However, the maximum
36 * SPI transfer size is 256 bytes, so at 5MHz we need a response
37 * time of perhaps <320us (200 bytes / 1600 bits).
38 */
39#define EC_MSG_PREAMBLE_COUNT 32
40
41/*
Doug Anderson9c0b54a2014-04-30 10:44:07 -070042 * Allow for a long time for the EC to respond. We support i2c
43 * tunneling and support fairly long messages for the tunnel (249
44 * bytes long at the moment). If we're talking to a 100 kHz device
45 * on the other end and need to transfer ~256 bytes, then we need:
46 * 10 us/bit * ~10 bits/byte * ~256 bytes = ~25ms
47 *
Doug Andersonca691f72017-03-01 12:58:32 +010048 * We'll wait 8 times that to handle clock stretching and other
49 * paranoia. Note that some battery gas gauge ICs claim to have a
50 * clock stretch of 144ms in rare situations. That's incentive for
51 * not directly passing i2c through, but it's too late for that for
52 * existing hardware.
Doug Anderson9c0b54a2014-04-30 10:44:07 -070053 *
54 * It's pretty unlikely that we'll really see a 249 byte tunnel in
55 * anything other than testing. If this was more common we might
56 * consider having slow commands like this require a GET_STATUS
57 * wait loop. The 'flash write' command would be another candidate
58 * for this, clocking in at 2-3ms.
59 */
Doug Andersonca691f72017-03-01 12:58:32 +010060#define EC_MSG_DEADLINE_MS 200
Simon Glassa17d94f2013-02-25 14:08:39 -080061
62/*
63 * Time between raising the SPI chip select (for the end of a
64 * transaction) and dropping it again (for the next transaction).
Derek Basehore49f91ac2013-11-18 11:30:48 +010065 * If we go too fast, the EC will miss the transaction. We know that we
66 * need at least 70 us with the 16 MHz STM32 EC, so go with 200 us to be
67 * safe.
Simon Glassa17d94f2013-02-25 14:08:39 -080068 */
Derek Basehore49f91ac2013-11-18 11:30:48 +010069#define EC_SPI_RECOVERY_TIME_NS (200 * 1000)
Simon Glassa17d94f2013-02-25 14:08:39 -080070
71/**
72 * struct cros_ec_spi - information about a SPI-connected EC
73 *
74 * @spi: SPI device we are connected to
Jon Hunterd501ff92017-11-14 14:43:28 +000075 * @last_transfer_ns: time that we last finished a transfer.
Alexandru M Stanff4378f2015-06-09 13:04:49 +020076 * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that
77 * is sent when we want to turn on CS at the start of a transaction.
Rhyland Klein01e73c82013-12-09 12:36:09 +010078 * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
79 * is sent when we want to turn off CS at the end of a transaction.
Simon Glassa17d94f2013-02-25 14:08:39 -080080 */
81struct cros_ec_spi {
82 struct spi_device *spi;
83 s64 last_transfer_ns;
Alexandru M Stanff4378f2015-06-09 13:04:49 +020084 unsigned int start_of_msg_delay;
Rhyland Klein01e73c82013-12-09 12:36:09 +010085 unsigned int end_of_msg_delay;
Simon Glassa17d94f2013-02-25 14:08:39 -080086};
87
88static void debug_packet(struct device *dev, const char *name, u8 *ptr,
Stephen Barberd3654072015-06-09 13:04:46 +020089 int len)
Simon Glassa17d94f2013-02-25 14:08:39 -080090{
91#ifdef DEBUG
92 int i;
93
94 dev_dbg(dev, "%s: ", name);
95 for (i = 0; i < len; i++)
Thierry Reding9e146f42013-11-18 11:30:49 +010096 pr_cont(" %02x", ptr[i]);
97
98 pr_cont("\n");
Simon Glassa17d94f2013-02-25 14:08:39 -080099#endif
100}
101
Stephen Barberd3654072015-06-09 13:04:46 +0200102static int terminate_request(struct cros_ec_device *ec_dev)
103{
104 struct cros_ec_spi *ec_spi = ec_dev->priv;
105 struct spi_message msg;
106 struct spi_transfer trans;
107 int ret;
108
109 /*
110 * Turn off CS, possibly adding a delay to ensure the rising edge
111 * doesn't come too soon after the end of the data.
112 */
113 spi_message_init(&msg);
114 memset(&trans, 0, sizeof(trans));
115 trans.delay_usecs = ec_spi->end_of_msg_delay;
116 spi_message_add_tail(&trans, &msg);
117
Nicolas Boichat6d6e44a2015-11-25 13:51:07 +0800118 ret = spi_sync_locked(ec_spi->spi, &msg);
Stephen Barberd3654072015-06-09 13:04:46 +0200119
120 /* Reset end-of-response timer */
121 ec_spi->last_transfer_ns = ktime_get_ns();
122 if (ret < 0) {
123 dev_err(ec_dev->dev,
124 "cs-deassert spi transfer failed: %d\n",
125 ret);
126 }
127
128 return ret;
129}
130
131/**
132 * receive_n_bytes - receive n bytes from the EC.
133 *
134 * Assumes buf is a pointer into the ec_dev->din buffer
135 */
136static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
137{
138 struct cros_ec_spi *ec_spi = ec_dev->priv;
139 struct spi_transfer trans;
140 struct spi_message msg;
141 int ret;
142
143 BUG_ON(buf - ec_dev->din + n > ec_dev->din_size);
144
145 memset(&trans, 0, sizeof(trans));
146 trans.cs_change = 1;
147 trans.rx_buf = buf;
148 trans.len = n;
149
150 spi_message_init(&msg);
151 spi_message_add_tail(&trans, &msg);
Nicolas Boichat6d6e44a2015-11-25 13:51:07 +0800152 ret = spi_sync_locked(ec_spi->spi, &msg);
Stephen Barberd3654072015-06-09 13:04:46 +0200153 if (ret < 0)
154 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
155
156 return ret;
157}
158
159/**
160 * cros_ec_spi_receive_packet - Receive a packet from the EC.
161 *
162 * This function has two phases: reading the preamble bytes (since if we read
163 * data from the EC before it is ready to send, we just get preamble) and
164 * reading the actual message.
165 *
166 * The received data is placed into ec_dev->din.
167 *
168 * @ec_dev: ChromeOS EC device
169 * @need_len: Number of message bytes we need to read
170 */
171static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
172 int need_len)
173{
174 struct ec_host_response *response;
175 u8 *ptr, *end;
176 int ret;
177 unsigned long deadline;
178 int todo;
179
Lee Jones8827a642015-10-28 16:42:45 +0000180 BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
Stephen Barberd3654072015-06-09 13:04:46 +0200181
182 /* Receive data until we see the header byte */
183 deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
184 while (true) {
185 unsigned long start_jiffies = jiffies;
186
187 ret = receive_n_bytes(ec_dev,
188 ec_dev->din,
189 EC_MSG_PREAMBLE_COUNT);
190 if (ret < 0)
191 return ret;
192
193 ptr = ec_dev->din;
194 for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
195 if (*ptr == EC_SPI_FRAME_START) {
196 dev_dbg(ec_dev->dev, "msg found at %zd\n",
197 ptr - ec_dev->din);
198 break;
199 }
200 }
201 if (ptr != end)
202 break;
203
204 /*
205 * Use the time at the start of the loop as a timeout. This
206 * gives us one last shot at getting the transfer and is useful
207 * in case we got context switched out for a while.
208 */
209 if (time_after(start_jiffies, deadline)) {
210 dev_warn(ec_dev->dev, "EC failed to respond in time\n");
211 return -ETIMEDOUT;
212 }
213 }
214
215 /*
216 * ptr now points to the header byte. Copy any valid data to the
217 * start of our buffer
218 */
219 todo = end - ++ptr;
220 BUG_ON(todo < 0 || todo > ec_dev->din_size);
221 todo = min(todo, need_len);
222 memmove(ec_dev->din, ptr, todo);
223 ptr = ec_dev->din + todo;
224 dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
225 need_len, todo);
226 need_len -= todo;
227
228 /* If the entire response struct wasn't read, get the rest of it. */
229 if (todo < sizeof(*response)) {
230 ret = receive_n_bytes(ec_dev, ptr, sizeof(*response) - todo);
231 if (ret < 0)
232 return -EBADMSG;
233 ptr += (sizeof(*response) - todo);
234 todo = sizeof(*response);
235 }
236
237 response = (struct ec_host_response *)ec_dev->din;
238
239 /* Abort if data_len is too large. */
240 if (response->data_len > ec_dev->din_size)
241 return -EMSGSIZE;
242
243 /* Receive data until we have it all */
244 while (need_len > 0) {
245 /*
246 * We can't support transfers larger than the SPI FIFO size
247 * unless we have DMA. We don't have DMA on the ISP SPI ports
248 * for Exynos. We need a way of asking SPI driver for
249 * maximum-supported transfer size.
250 */
251 todo = min(need_len, 256);
252 dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
253 todo, need_len, ptr - ec_dev->din);
254
255 ret = receive_n_bytes(ec_dev, ptr, todo);
256 if (ret < 0)
257 return ret;
258
259 ptr += todo;
260 need_len -= todo;
261 }
262
263 dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
264
265 return 0;
266}
267
Simon Glassa17d94f2013-02-25 14:08:39 -0800268/**
269 * cros_ec_spi_receive_response - Receive a response from the EC.
270 *
271 * This function has two phases: reading the preamble bytes (since if we read
272 * data from the EC before it is ready to send, we just get preamble) and
273 * reading the actual message.
274 *
275 * The received data is placed into ec_dev->din.
276 *
277 * @ec_dev: ChromeOS EC device
278 * @need_len: Number of message bytes we need to read
279 */
280static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
281 int need_len)
282{
Simon Glassa17d94f2013-02-25 14:08:39 -0800283 u8 *ptr, *end;
284 int ret;
285 unsigned long deadline;
286 int todo;
287
Lee Jones8827a642015-10-28 16:42:45 +0000288 BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
Stephen Barberd3654072015-06-09 13:04:46 +0200289
Simon Glassa17d94f2013-02-25 14:08:39 -0800290 /* Receive data until we see the header byte */
291 deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
Doug Andersonc9a81d62014-04-30 10:44:06 -0700292 while (true) {
293 unsigned long start_jiffies = jiffies;
294
Stephen Barberd3654072015-06-09 13:04:46 +0200295 ret = receive_n_bytes(ec_dev,
296 ec_dev->din,
297 EC_MSG_PREAMBLE_COUNT);
298 if (ret < 0)
Simon Glassa17d94f2013-02-25 14:08:39 -0800299 return ret;
Simon Glassa17d94f2013-02-25 14:08:39 -0800300
Stephen Barberd3654072015-06-09 13:04:46 +0200301 ptr = ec_dev->din;
Simon Glassa17d94f2013-02-25 14:08:39 -0800302 for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
Stephen Barberd3654072015-06-09 13:04:46 +0200303 if (*ptr == EC_SPI_FRAME_START) {
Geert Uytterhoevenc34924b2013-05-08 23:37:45 +0200304 dev_dbg(ec_dev->dev, "msg found at %zd\n",
Simon Glassa17d94f2013-02-25 14:08:39 -0800305 ptr - ec_dev->din);
306 break;
307 }
308 }
Doug Andersonc9a81d62014-04-30 10:44:06 -0700309 if (ptr != end)
310 break;
Simon Glassa17d94f2013-02-25 14:08:39 -0800311
Doug Andersonc9a81d62014-04-30 10:44:06 -0700312 /*
313 * Use the time at the start of the loop as a timeout. This
314 * gives us one last shot at getting the transfer and is useful
315 * in case we got context switched out for a while.
316 */
317 if (time_after(start_jiffies, deadline)) {
Simon Glassa17d94f2013-02-25 14:08:39 -0800318 dev_warn(ec_dev->dev, "EC failed to respond in time\n");
319 return -ETIMEDOUT;
320 }
Doug Andersonc9a81d62014-04-30 10:44:06 -0700321 }
Simon Glassa17d94f2013-02-25 14:08:39 -0800322
323 /*
324 * ptr now points to the header byte. Copy any valid data to the
325 * start of our buffer
326 */
327 todo = end - ++ptr;
328 BUG_ON(todo < 0 || todo > ec_dev->din_size);
329 todo = min(todo, need_len);
330 memmove(ec_dev->din, ptr, todo);
331 ptr = ec_dev->din + todo;
332 dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
333 need_len, todo);
334 need_len -= todo;
335
336 /* Receive data until we have it all */
337 while (need_len > 0) {
338 /*
339 * We can't support transfers larger than the SPI FIFO size
340 * unless we have DMA. We don't have DMA on the ISP SPI ports
341 * for Exynos. We need a way of asking SPI driver for
342 * maximum-supported transfer size.
343 */
344 todo = min(need_len, 256);
Geert Uytterhoevenc34924b2013-05-08 23:37:45 +0200345 dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
Simon Glassa17d94f2013-02-25 14:08:39 -0800346 todo, need_len, ptr - ec_dev->din);
347
Stephen Barberd3654072015-06-09 13:04:46 +0200348 ret = receive_n_bytes(ec_dev, ptr, todo);
349 if (ret < 0)
Simon Glassa17d94f2013-02-25 14:08:39 -0800350 return ret;
Simon Glassa17d94f2013-02-25 14:08:39 -0800351
352 debug_packet(ec_dev->dev, "interim", ptr, todo);
353 ptr += todo;
354 need_len -= todo;
355 }
356
Geert Uytterhoevenc34924b2013-05-08 23:37:45 +0200357 dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
Simon Glassa17d94f2013-02-25 14:08:39 -0800358
359 return 0;
360}
361
362/**
Stephen Barberd3654072015-06-09 13:04:46 +0200363 * cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
364 *
365 * @ec_dev: ChromeOS EC device
366 * @ec_msg: Message to transfer
367 */
368static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
369 struct cros_ec_command *ec_msg)
370{
Stephen Barberd3654072015-06-09 13:04:46 +0200371 struct ec_host_response *response;
372 struct cros_ec_spi *ec_spi = ec_dev->priv;
Alexandru M Stanff4378f2015-06-09 13:04:49 +0200373 struct spi_transfer trans, trans_delay;
Stephen Barberd3654072015-06-09 13:04:46 +0200374 struct spi_message msg;
375 int i, len;
376 u8 *ptr;
377 u8 *rx_buf;
378 u8 sum;
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700379 u8 rx_byte;
Stephen Barberd3654072015-06-09 13:04:46 +0200380 int ret = 0, final_ret;
Jon Hunterd501ff92017-11-14 14:43:28 +0000381 unsigned long delay;
Stephen Barberd3654072015-06-09 13:04:46 +0200382
383 len = cros_ec_prepare_tx(ec_dev, ec_msg);
Stephen Barberd3654072015-06-09 13:04:46 +0200384 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
385
386 /* If it's too soon to do another transaction, wait */
Jon Hunterd501ff92017-11-14 14:43:28 +0000387 delay = ktime_get_ns() - ec_spi->last_transfer_ns;
388 if (delay < EC_SPI_RECOVERY_TIME_NS)
389 ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
Stephen Barberd3654072015-06-09 13:04:46 +0200390
391 rx_buf = kzalloc(len, GFP_KERNEL);
Nicolas Boichat6d6e44a2015-11-25 13:51:07 +0800392 if (!rx_buf)
393 return -ENOMEM;
394
395 spi_bus_lock(ec_spi->spi->master);
Stephen Barberd3654072015-06-09 13:04:46 +0200396
Alexandru M Stanff4378f2015-06-09 13:04:49 +0200397 /*
398 * Leave a gap between CS assertion and clocking of data to allow the
399 * EC time to wakeup.
400 */
401 spi_message_init(&msg);
402 if (ec_spi->start_of_msg_delay) {
403 memset(&trans_delay, 0, sizeof(trans_delay));
404 trans_delay.delay_usecs = ec_spi->start_of_msg_delay;
405 spi_message_add_tail(&trans_delay, &msg);
406 }
407
Stephen Barberd3654072015-06-09 13:04:46 +0200408 /* Transmit phase - send our message */
409 memset(&trans, 0, sizeof(trans));
410 trans.tx_buf = ec_dev->dout;
411 trans.rx_buf = rx_buf;
412 trans.len = len;
413 trans.cs_change = 1;
Stephen Barberd3654072015-06-09 13:04:46 +0200414 spi_message_add_tail(&trans, &msg);
Nicolas Boichat6d6e44a2015-11-25 13:51:07 +0800415 ret = spi_sync_locked(ec_spi->spi, &msg);
Stephen Barberd3654072015-06-09 13:04:46 +0200416
417 /* Get the response */
418 if (!ret) {
419 /* Verify that EC can process command */
420 for (i = 0; i < len; i++) {
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700421 rx_byte = rx_buf[i];
Brian Norris11799562018-05-22 17:23:10 -0700422 /*
423 * Seeing the PAST_END, RX_BAD_DATA, or NOT_READY
424 * markers are all signs that the EC didn't fully
425 * receive our command. e.g., if the EC is flashing
426 * itself, it can't respond to any commands and instead
427 * clocks out EC_SPI_PAST_END from its SPI hardware
428 * buffer. Similar occurrences can happen if the AP is
429 * too slow to clock out data after asserting CS -- the
430 * EC will abort and fill its buffer with
431 * EC_SPI_RX_BAD_DATA.
432 *
433 * In all cases, these errors should be safe to retry.
434 * Report -EAGAIN and let the caller decide what to do
435 * about that.
436 */
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700437 if (rx_byte == EC_SPI_PAST_END ||
438 rx_byte == EC_SPI_RX_BAD_DATA ||
439 rx_byte == EC_SPI_NOT_READY) {
Brian Norris11799562018-05-22 17:23:10 -0700440 ret = -EAGAIN;
Stephen Barberd3654072015-06-09 13:04:46 +0200441 break;
442 }
Stephen Barberd3654072015-06-09 13:04:46 +0200443 }
Stephen Barberd3654072015-06-09 13:04:46 +0200444 }
445
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700446 if (!ret)
447 ret = cros_ec_spi_receive_packet(ec_dev,
448 ec_msg->insize + sizeof(*response));
Brian Norris11799562018-05-22 17:23:10 -0700449 else if (ret != -EAGAIN)
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700450 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
451
Stephen Barberd3654072015-06-09 13:04:46 +0200452 final_ret = terminate_request(ec_dev);
Nicolas Boichat6d6e44a2015-11-25 13:51:07 +0800453
454 spi_bus_unlock(ec_spi->spi->master);
455
Stephen Barberd3654072015-06-09 13:04:46 +0200456 if (!ret)
457 ret = final_ret;
458 if (ret < 0)
459 goto exit;
460
461 ptr = ec_dev->din;
462
463 /* check response error code */
464 response = (struct ec_host_response *)ptr;
465 ec_msg->result = response->result;
466
467 ret = cros_ec_check_result(ec_dev, ec_msg);
468 if (ret)
469 goto exit;
470
471 len = response->data_len;
472 sum = 0;
473 if (len > ec_msg->insize) {
474 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
475 len, ec_msg->insize);
476 ret = -EMSGSIZE;
477 goto exit;
478 }
479
480 for (i = 0; i < sizeof(*response); i++)
481 sum += ptr[i];
482
483 /* copy response packet payload and compute checksum */
484 memcpy(ec_msg->data, ptr + sizeof(*response), len);
485 for (i = 0; i < len; i++)
486 sum += ec_msg->data[i];
487
488 if (sum) {
489 dev_err(ec_dev->dev,
490 "bad packet checksum, calculated %x\n",
491 sum);
492 ret = -EBADMSG;
493 goto exit;
494 }
495
496 ret = len;
497exit:
498 kfree(rx_buf);
499 if (ec_msg->command == EC_CMD_REBOOT_EC)
500 msleep(EC_REBOOT_DELAY_MS);
501
502 return ret;
503}
504
505/**
Bill Richardson7e6cb5b2014-06-18 11:14:00 -0700506 * cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
Simon Glassa17d94f2013-02-25 14:08:39 -0800507 *
508 * @ec_dev: ChromeOS EC device
509 * @ec_msg: Message to transfer
510 */
Bill Richardson7e6cb5b2014-06-18 11:14:00 -0700511static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
Bill Richardson5d4773e2014-06-18 11:14:02 -0700512 struct cros_ec_command *ec_msg)
Simon Glassa17d94f2013-02-25 14:08:39 -0800513{
514 struct cros_ec_spi *ec_spi = ec_dev->priv;
515 struct spi_transfer trans;
516 struct spi_message msg;
517 int i, len;
518 u8 *ptr;
Stephen Barberd3654072015-06-09 13:04:46 +0200519 u8 *rx_buf;
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700520 u8 rx_byte;
Simon Glassa17d94f2013-02-25 14:08:39 -0800521 int sum;
522 int ret = 0, final_ret;
Jon Hunterd501ff92017-11-14 14:43:28 +0000523 unsigned long delay;
Simon Glassa17d94f2013-02-25 14:08:39 -0800524
525 len = cros_ec_prepare_tx(ec_dev, ec_msg);
526 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
527
528 /* If it's too soon to do another transaction, wait */
Jon Hunterd501ff92017-11-14 14:43:28 +0000529 delay = ktime_get_ns() - ec_spi->last_transfer_ns;
530 if (delay < EC_SPI_RECOVERY_TIME_NS)
531 ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
Simon Glassa17d94f2013-02-25 14:08:39 -0800532
Stephen Barberd3654072015-06-09 13:04:46 +0200533 rx_buf = kzalloc(len, GFP_KERNEL);
Nicolas Boichat6d6e44a2015-11-25 13:51:07 +0800534 if (!rx_buf)
535 return -ENOMEM;
536
537 spi_bus_lock(ec_spi->spi->master);
Stephen Barberd3654072015-06-09 13:04:46 +0200538
Simon Glassa17d94f2013-02-25 14:08:39 -0800539 /* Transmit phase - send our message */
540 debug_packet(ec_dev->dev, "out", ec_dev->dout, len);
Thierry Redingdaf93d22013-12-09 12:36:10 +0100541 memset(&trans, 0, sizeof(trans));
Simon Glassa17d94f2013-02-25 14:08:39 -0800542 trans.tx_buf = ec_dev->dout;
Stephen Barberd3654072015-06-09 13:04:46 +0200543 trans.rx_buf = rx_buf;
Simon Glassa17d94f2013-02-25 14:08:39 -0800544 trans.len = len;
545 trans.cs_change = 1;
546 spi_message_init(&msg);
547 spi_message_add_tail(&trans, &msg);
Nicolas Boichat6d6e44a2015-11-25 13:51:07 +0800548 ret = spi_sync_locked(ec_spi->spi, &msg);
Simon Glassa17d94f2013-02-25 14:08:39 -0800549
550 /* Get the response */
551 if (!ret) {
Stephen Barberd3654072015-06-09 13:04:46 +0200552 /* Verify that EC can process command */
553 for (i = 0; i < len; i++) {
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700554 rx_byte = rx_buf[i];
Brian Norris11799562018-05-22 17:23:10 -0700555 /* See comments in cros_ec_pkt_xfer_spi() */
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700556 if (rx_byte == EC_SPI_PAST_END ||
557 rx_byte == EC_SPI_RX_BAD_DATA ||
558 rx_byte == EC_SPI_NOT_READY) {
Brian Norris11799562018-05-22 17:23:10 -0700559 ret = -EAGAIN;
Stephen Barberd3654072015-06-09 13:04:46 +0200560 break;
561 }
Stephen Barberd3654072015-06-09 13:04:46 +0200562 }
Simon Glassa17d94f2013-02-25 14:08:39 -0800563 }
564
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700565 if (!ret)
566 ret = cros_ec_spi_receive_response(ec_dev,
567 ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
Brian Norris11799562018-05-22 17:23:10 -0700568 else if (ret != -EAGAIN)
Shawn Nematbakhsh001dde92017-09-27 14:35:27 -0700569 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
570
Stephen Barberd3654072015-06-09 13:04:46 +0200571 final_ret = terminate_request(ec_dev);
Nicolas Boichat6d6e44a2015-11-25 13:51:07 +0800572
573 spi_bus_unlock(ec_spi->spi->master);
574
Simon Glassa17d94f2013-02-25 14:08:39 -0800575 if (!ret)
576 ret = final_ret;
Stephen Barberd3654072015-06-09 13:04:46 +0200577 if (ret < 0)
Doug Anderson362196e2014-04-30 10:44:05 -0700578 goto exit;
Simon Glassa17d94f2013-02-25 14:08:39 -0800579
Simon Glassa17d94f2013-02-25 14:08:39 -0800580 ptr = ec_dev->din;
Bill Richardson6db07b62014-06-18 11:14:05 -0700581
582 /* check response error code */
583 ec_msg->result = ptr[0];
584 ret = cros_ec_check_result(ec_dev, ec_msg);
585 if (ret)
Doug Anderson362196e2014-04-30 10:44:05 -0700586 goto exit;
Bill Richardson6db07b62014-06-18 11:14:05 -0700587
Simon Glassa17d94f2013-02-25 14:08:39 -0800588 len = ptr[1];
589 sum = ptr[0] + ptr[1];
Bill Richardson5d4773e2014-06-18 11:14:02 -0700590 if (len > ec_msg->insize) {
Simon Glassa17d94f2013-02-25 14:08:39 -0800591 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
Bill Richardson5d4773e2014-06-18 11:14:02 -0700592 len, ec_msg->insize);
Doug Anderson362196e2014-04-30 10:44:05 -0700593 ret = -ENOSPC;
594 goto exit;
Simon Glassa17d94f2013-02-25 14:08:39 -0800595 }
596
597 /* copy response packet payload and compute checksum */
598 for (i = 0; i < len; i++) {
599 sum += ptr[i + 2];
Bill Richardson5d4773e2014-06-18 11:14:02 -0700600 if (ec_msg->insize)
Javier Martinez Canillasa8411782015-06-09 13:04:42 +0200601 ec_msg->data[i] = ptr[i + 2];
Simon Glassa17d94f2013-02-25 14:08:39 -0800602 }
603 sum &= 0xff;
604
605 debug_packet(ec_dev->dev, "in", ptr, len + 3);
606
607 if (sum != ptr[len + 2]) {
608 dev_err(ec_dev->dev,
609 "bad packet checksum, expected %02x, got %02x\n",
610 sum, ptr[len + 2]);
Doug Anderson362196e2014-04-30 10:44:05 -0700611 ret = -EBADMSG;
612 goto exit;
Simon Glassa17d94f2013-02-25 14:08:39 -0800613 }
614
Bill Richardson12ebc8a2014-06-18 11:14:06 -0700615 ret = len;
Doug Anderson362196e2014-04-30 10:44:05 -0700616exit:
Stephen Barberd3654072015-06-09 13:04:46 +0200617 kfree(rx_buf);
Doug Anderson659e1422014-09-18 17:18:54 +0200618 if (ec_msg->command == EC_CMD_REBOOT_EC)
619 msleep(EC_REBOOT_DELAY_MS);
620
Doug Anderson362196e2014-04-30 10:44:05 -0700621 return ret;
Simon Glassa17d94f2013-02-25 14:08:39 -0800622}
623
Rhyland Klein01e73c82013-12-09 12:36:09 +0100624static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
625{
626 struct device_node *np = dev->of_node;
627 u32 val;
628 int ret;
629
Alexandru M Stanff4378f2015-06-09 13:04:49 +0200630 ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val);
631 if (!ret)
632 ec_spi->start_of_msg_delay = val;
633
Rhyland Klein01e73c82013-12-09 12:36:09 +0100634 ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
635 if (!ret)
636 ec_spi->end_of_msg_delay = val;
637}
638
Thierry Reding9922b412013-11-25 13:22:30 +0100639static int cros_ec_spi_probe(struct spi_device *spi)
Simon Glassa17d94f2013-02-25 14:08:39 -0800640{
641 struct device *dev = &spi->dev;
642 struct cros_ec_device *ec_dev;
643 struct cros_ec_spi *ec_spi;
644 int err;
645
646 spi->bits_per_word = 8;
647 spi->mode = SPI_MODE_0;
648 err = spi_setup(spi);
649 if (err < 0)
650 return err;
651
652 ec_spi = devm_kzalloc(dev, sizeof(*ec_spi), GFP_KERNEL);
653 if (ec_spi == NULL)
654 return -ENOMEM;
655 ec_spi->spi = spi;
656 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
657 if (!ec_dev)
658 return -ENOMEM;
659
Rhyland Klein01e73c82013-12-09 12:36:09 +0100660 /* Check for any DT properties */
661 cros_ec_spi_dt_probe(ec_spi, dev);
662
Simon Glassa17d94f2013-02-25 14:08:39 -0800663 spi_set_drvdata(spi, ec_dev);
Simon Glassa17d94f2013-02-25 14:08:39 -0800664 ec_dev->dev = dev;
665 ec_dev->priv = ec_spi;
666 ec_dev->irq = spi->irq;
Bill Richardson7e6cb5b2014-06-18 11:14:00 -0700667 ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
Stephen Barberd3654072015-06-09 13:04:46 +0200668 ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
Simon Glassa17d94f2013-02-25 14:08:39 -0800669 ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
Stephen Barber2c7589a2015-06-09 13:04:45 +0200670 ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
671 sizeof(struct ec_host_response) +
672 sizeof(struct ec_response_get_protocol_info);
673 ec_dev->dout_size = sizeof(struct ec_host_request);
Simon Glassa17d94f2013-02-25 14:08:39 -0800674
Jon Hunter15d83742017-11-14 14:43:27 +0000675 ec_spi->last_transfer_ns = ktime_get_ns();
Stephen Barberd3654072015-06-09 13:04:46 +0200676
Simon Glassa17d94f2013-02-25 14:08:39 -0800677 err = cros_ec_register(ec_dev);
678 if (err) {
679 dev_err(dev, "cannot register EC\n");
680 return err;
681 }
682
Prathyush Kfb504972014-06-16 14:12:23 -0700683 device_init_wakeup(&spi->dev, true);
684
Simon Glassa17d94f2013-02-25 14:08:39 -0800685 return 0;
686}
687
Thierry Reding9922b412013-11-25 13:22:30 +0100688static int cros_ec_spi_remove(struct spi_device *spi)
Simon Glassa17d94f2013-02-25 14:08:39 -0800689{
690 struct cros_ec_device *ec_dev;
691
692 ec_dev = spi_get_drvdata(spi);
693 cros_ec_remove(ec_dev);
694
695 return 0;
696}
697
698#ifdef CONFIG_PM_SLEEP
699static int cros_ec_spi_suspend(struct device *dev)
700{
701 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
702
703 return cros_ec_suspend(ec_dev);
704}
705
706static int cros_ec_spi_resume(struct device *dev)
707{
708 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
709
710 return cros_ec_resume(ec_dev);
711}
712#endif
713
714static SIMPLE_DEV_PM_OPS(cros_ec_spi_pm_ops, cros_ec_spi_suspend,
715 cros_ec_spi_resume);
716
Javier Martinez Canillasa78ea192015-08-20 09:07:22 +0200717static const struct of_device_id cros_ec_spi_of_match[] = {
718 { .compatible = "google,cros-ec-spi", },
719 { /* sentinel */ },
720};
721MODULE_DEVICE_TABLE(of, cros_ec_spi_of_match);
722
Simon Glassa17d94f2013-02-25 14:08:39 -0800723static const struct spi_device_id cros_ec_spi_id[] = {
724 { "cros-ec-spi", 0 },
725 { }
726};
727MODULE_DEVICE_TABLE(spi, cros_ec_spi_id);
728
729static struct spi_driver cros_ec_driver_spi = {
730 .driver = {
731 .name = "cros-ec-spi",
Javier Martinez Canillasa78ea192015-08-20 09:07:22 +0200732 .of_match_table = of_match_ptr(cros_ec_spi_of_match),
Simon Glassa17d94f2013-02-25 14:08:39 -0800733 .pm = &cros_ec_spi_pm_ops,
734 },
Thierry Reding9922b412013-11-25 13:22:30 +0100735 .probe = cros_ec_spi_probe,
736 .remove = cros_ec_spi_remove,
Simon Glassa17d94f2013-02-25 14:08:39 -0800737 .id_table = cros_ec_spi_id,
738};
739
740module_spi_driver(cros_ec_driver_spi);
741
Thierry Redingea0f8b02013-12-09 11:05:38 +0100742MODULE_LICENSE("GPL v2");
Simon Glassa17d94f2013-02-25 14:08:39 -0800743MODULE_DESCRIPTION("ChromeOS EC multi function device (SPI)");