1 // SPDX-License-Identifier: GPL-2.0
2 // ISHTP interface for ChromeOS Embedded Controller
3 //
4 // Copyright (c) 2019, Intel Corporation.
5 //
6 // ISHTP client driver for talking to the Chrome OS EC firmware running
7 // on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
8 // (ISH-TP).
9 
10 #include <linux/delay.h>
11 #include <linux/module.h>
12 #include <linux/pci.h>
13 #include <linux/platform_data/cros_ec_commands.h>
14 #include <linux/platform_data/cros_ec_proto.h>
15 #include <linux/intel-ish-client-if.h>
16 
17 #include "cros_ec.h"
18 
19 /*
20  * ISH TX/RX ring buffer pool size
21  *
22  * The AP->ISH messages and corresponding ISH->AP responses are
23  * serialized. We need 1 TX and 1 RX buffer for these.
24  *
25  * The MKBP ISH->AP events are serialized. We need one additional RX
26  * buffer for them.
27  */
28 #define CROS_ISH_CL_TX_RING_SIZE		8
29 #define CROS_ISH_CL_RX_RING_SIZE		8
30 
31 /* ISH CrOS EC Host Commands */
32 enum cros_ec_ish_channel {
33 	CROS_EC_COMMAND = 1,			/* AP->ISH message */
34 	CROS_MKBP_EVENT = 2,			/* ISH->AP events */
35 };
36 
37 /*
38  * ISH firmware timeout for 1 message send failure is 1Hz, and the
39  * firmware will retry 2 times, so 3Hz is used for timeout.
40  */
41 #define ISHTP_SEND_TIMEOUT			(3 * HZ)
42 
43 /* ISH Transport CrOS EC ISH client unique GUID */
44 static const guid_t cros_ish_guid =
45 	GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
46 		  0xb0, 0xd8, 0x9e, 0x7c, 0xda,	0xe0, 0xd6, 0xa0);
47 
48 struct header {
49 	u8 channel;
50 	u8 status;
51 	u8 token;
52 	u8 reserved;
53 } __packed;
54 
55 struct cros_ish_out_msg {
56 	struct header hdr;
57 	struct ec_host_request ec_request;
58 } __packed;
59 
60 struct cros_ish_in_msg {
61 	struct header hdr;
62 	struct ec_host_response ec_response;
63 } __packed;
64 
65 #define IN_MSG_EC_RESPONSE_PREAMBLE					\
66 	offsetof(struct cros_ish_in_msg, ec_response)
67 
68 #define OUT_MSG_EC_REQUEST_PREAMBLE					\
69 	offsetof(struct cros_ish_out_msg, ec_request)
70 
71 #define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
72 
73 /*
74  * The Read-Write Semaphore is used to prevent message TX or RX while
75  * the ishtp client is being initialized or undergoing reset.
76  *
77  * The readers are the kernel function calls responsible for IA->ISH
78  * and ISH->AP messaging.
79  *
80  * The writers are .reset() and .probe() function.
81  */
82 static DECLARE_RWSEM(init_lock);
83 
84 /**
85  * struct response_info - Encapsulate firmware response related
86  * information for passing between function ish_send() and
87  * process_recv() callback.
88  *
89  * @data: Copy the data received from firmware here.
90  * @max_size: Max size allocated for the @data buffer. If the received
91  * data exceeds this value, we log an error.
92  * @size: Actual size of data received from firmware.
93  * @error: 0 for success, negative error code for a failure in process_recv().
94  * @token: Expected token for response that we are waiting on.
95  * @received: Set to true on receiving a valid firmware	response to host command
96  * @wait_queue: Wait queue for host to wait for firmware response.
97  */
98 struct response_info {
99 	void *data;
100 	size_t max_size;
101 	size_t size;
102 	int error;
103 	u8 token;
104 	bool received;
105 	wait_queue_head_t wait_queue;
106 };
107 
108 /**
109  * struct ishtp_cl_data - Encapsulate per ISH TP Client.
110  *
111  * @cros_ish_cl: ISHTP firmware client instance.
112  * @cl_device: ISHTP client device instance.
113  * @response: Response info passing between ish_send() and process_recv().
114  * @work_ishtp_reset: Work queue reset handling.
115  * @work_ec_evt: Work queue for EC events.
116  * @ec_dev: CrOS EC MFD device.
117  *
118  * This structure is used to store per client data.
119  */
120 struct ishtp_cl_data {
121 	struct ishtp_cl *cros_ish_cl;
122 	struct ishtp_cl_device *cl_device;
123 
124 	/*
125 	 * Used for passing firmware response information between
126 	 * ish_send() and process_recv() callback.
127 	 */
128 	struct response_info response;
129 
130 	struct work_struct work_ishtp_reset;
131 	struct work_struct work_ec_evt;
132 	struct cros_ec_device *ec_dev;
133 };
134 
135 /**
136  * ish_evt_handler - ISH to AP event handler
137  * @work: Work struct
138  */
139 static void ish_evt_handler(struct work_struct *work)
140 {
141 	struct ishtp_cl_data *client_data =
142 		container_of(work, struct ishtp_cl_data, work_ec_evt);
143 	struct cros_ec_device *ec_dev = client_data->ec_dev;
144 	bool ec_has_more_events;
145 
146 	do {
147 		ec_has_more_events = cros_ec_handle_event(ec_dev);
148 	} while (ec_has_more_events);
149 }
150 
151 /**
152  * ish_send() - Send message from host to firmware
153  *
154  * @client_data: Client data instance
155  * @out_msg: Message buffer to be sent to firmware
156  * @out_size: Size of out going message
157  * @in_msg: Message buffer where the incoming data is copied. This buffer
158  * is allocated by calling
159  * @in_size: Max size of incoming message
160  *
161  * Return: Number of bytes copied in the in_msg on success, negative
162  * error code on failure.
163  */
164 static int ish_send(struct ishtp_cl_data *client_data,
165 		    u8 *out_msg, size_t out_size,
166 		    u8 *in_msg, size_t in_size)
167 {
168 	static u8 next_token;
169 	int rv;
170 	struct header *out_hdr = (struct header *)out_msg;
171 	struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
172 
173 	dev_dbg(cl_data_to_dev(client_data),
174 		"%s: channel=%02u status=%02u\n",
175 		__func__, out_hdr->channel, out_hdr->status);
176 
177 	/* Setup for incoming response */
178 	client_data->response.data = in_msg;
179 	client_data->response.max_size = in_size;
180 	client_data->response.error = 0;
181 	client_data->response.token = next_token++;
182 	client_data->response.received = false;
183 
184 	out_hdr->token = client_data->response.token;
185 
186 	rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
187 	if (rv) {
188 		dev_err(cl_data_to_dev(client_data),
189 			"ishtp_cl_send error %d\n", rv);
190 		return rv;
191 	}
192 
193 	wait_event_interruptible_timeout(client_data->response.wait_queue,
194 					 client_data->response.received,
195 					 ISHTP_SEND_TIMEOUT);
196 	if (!client_data->response.received) {
197 		dev_err(cl_data_to_dev(client_data),
198 			"Timed out for response to host message\n");
199 		return -ETIMEDOUT;
200 	}
201 
202 	if (client_data->response.error < 0)
203 		return client_data->response.error;
204 
205 	return client_data->response.size;
206 }
207 
208 /**
209  * process_recv() - Received and parse incoming packet
210  * @cros_ish_cl: Client instance to get stats
211  * @rb_in_proc: Host interface message buffer
212  * @timestamp: Timestamp of when parent callback started
213  *
214  * Parse the incoming packet. If it is a response packet then it will
215  * update per instance flags and wake up the caller waiting to for the
216  * response. If it is an event packet then it will schedule event work.
217  */
218 static void process_recv(struct ishtp_cl *cros_ish_cl,
219 			 struct ishtp_cl_rb *rb_in_proc, ktime_t timestamp)
220 {
221 	size_t data_len = rb_in_proc->buf_idx;
222 	struct ishtp_cl_data *client_data =
223 		ishtp_get_client_data(cros_ish_cl);
224 	struct device *dev = cl_data_to_dev(client_data);
225 	struct cros_ish_in_msg *in_msg =
226 		(struct cros_ish_in_msg *)rb_in_proc->buffer.data;
227 
228 	/* Proceed only if reset or init is not in progress */
229 	if (!down_read_trylock(&init_lock)) {
230 		/* Free the buffer */
231 		ishtp_cl_io_rb_recycle(rb_in_proc);
232 		dev_warn(dev,
233 			 "Host is not ready to receive incoming messages\n");
234 		return;
235 	}
236 
237 	/*
238 	 * All firmware messages contain a header. Check the buffer size
239 	 * before accessing elements inside.
240 	 */
241 	if (!rb_in_proc->buffer.data) {
242 		dev_warn(dev, "rb_in_proc->buffer.data returned null");
243 		client_data->response.error = -EBADMSG;
244 		goto end_error;
245 	}
246 
247 	if (data_len < sizeof(struct header)) {
248 		dev_err(dev, "data size %zu is less than header %zu\n",
249 			data_len, sizeof(struct header));
250 		client_data->response.error = -EMSGSIZE;
251 		goto end_error;
252 	}
253 
254 	dev_dbg(dev, "channel=%02u status=%02u\n",
255 		in_msg->hdr.channel, in_msg->hdr.status);
256 
257 	switch (in_msg->hdr.channel) {
258 	case CROS_EC_COMMAND:
259 		if (client_data->response.received) {
260 			dev_err(dev,
261 				"Previous firmware message not yet processed\n");
262 			goto end_error;
263 		}
264 
265 		if (client_data->response.token != in_msg->hdr.token) {
266 			dev_err_ratelimited(dev,
267 					    "Dropping old response token %d\n",
268 					    in_msg->hdr.token);
269 			goto end_error;
270 		}
271 
272 		/* Sanity check */
273 		if (!client_data->response.data) {
274 			dev_err(dev,
275 				"Receiving buffer is null. Should be allocated by calling function\n");
276 			client_data->response.error = -EINVAL;
277 			goto error_wake_up;
278 		}
279 
280 		if (data_len > client_data->response.max_size) {
281 			dev_err(dev,
282 				"Received buffer size %zu is larger than allocated buffer %zu\n",
283 				data_len, client_data->response.max_size);
284 			client_data->response.error = -EMSGSIZE;
285 			goto error_wake_up;
286 		}
287 
288 		if (in_msg->hdr.status) {
289 			dev_err(dev, "firmware returned status %d\n",
290 				in_msg->hdr.status);
291 			client_data->response.error = -EIO;
292 			goto error_wake_up;
293 		}
294 
295 		/* Update the actual received buffer size */
296 		client_data->response.size = data_len;
297 
298 		/*
299 		 * Copy the buffer received in firmware response for the
300 		 * calling thread.
301 		 */
302 		memcpy(client_data->response.data,
303 		       rb_in_proc->buffer.data, data_len);
304 
305 error_wake_up:
306 		/* Free the buffer since we copied data or didn't need it */
307 		ishtp_cl_io_rb_recycle(rb_in_proc);
308 		rb_in_proc = NULL;
309 
310 		/* Set flag before waking up the caller */
311 		client_data->response.received = true;
312 
313 		/* Wake the calling thread */
314 		wake_up_interruptible(&client_data->response.wait_queue);
315 
316 		break;
317 
318 	case CROS_MKBP_EVENT:
319 		/* Free the buffer. This is just an event without data */
320 		ishtp_cl_io_rb_recycle(rb_in_proc);
321 		rb_in_proc = NULL;
322 		/*
323 		 * Set timestamp from beginning of function since we actually
324 		 * got an incoming MKBP event
325 		 */
326 		client_data->ec_dev->last_event_time = timestamp;
327 		schedule_work(&client_data->work_ec_evt);
328 
329 		break;
330 
331 	default:
332 		dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
333 	}
334 
335 end_error:
336 	/* Free the buffer if we already haven't */
337 	if (rb_in_proc)
338 		ishtp_cl_io_rb_recycle(rb_in_proc);
339 
340 	up_read(&init_lock);
341 }
342 
343 /**
344  * ish_event_cb() - bus driver callback for incoming message
345  * @cl_device: ISHTP client device for which this message is targeted.
346  *
347  * Remove the packet from the list and process the message by calling
348  * process_recv.
349  */
350 static void ish_event_cb(struct ishtp_cl_device *cl_device)
351 {
352 	struct ishtp_cl_rb *rb_in_proc;
353 	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
354 	ktime_t timestamp;
355 
356 	/*
357 	 * Take timestamp as close to hardware interrupt as possible for sensor
358 	 * timestamps.
359 	 */
360 	timestamp = cros_ec_get_time_ns();
361 
362 	while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
363 		/* Decide what to do with received data */
364 		process_recv(cros_ish_cl, rb_in_proc, timestamp);
365 	}
366 }
367 
368 /**
369  * cros_ish_init() - Init function for ISHTP client
370  * @cros_ish_cl: ISHTP client instance
371  *
372  * This function complete the initializtion of the client.
373  *
374  * Return: 0 for success, negative error code for failure.
375  */
376 static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
377 {
378 	int rv;
379 	struct ishtp_device *dev;
380 	struct ishtp_fw_client *fw_client;
381 	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
382 
383 	rv = ishtp_cl_link(cros_ish_cl);
384 	if (rv) {
385 		dev_err(cl_data_to_dev(client_data),
386 			"ishtp_cl_link failed\n");
387 		return rv;
388 	}
389 
390 	dev = ishtp_get_ishtp_device(cros_ish_cl);
391 
392 	/* Connect to firmware client */
393 	ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
394 	ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
395 
396 	fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
397 	if (!fw_client) {
398 		dev_err(cl_data_to_dev(client_data),
399 			"ish client uuid not found\n");
400 		rv = -ENOENT;
401 		goto err_cl_unlink;
402 	}
403 
404 	ishtp_cl_set_fw_client_id(cros_ish_cl,
405 				  ishtp_get_fw_client_id(fw_client));
406 	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
407 
408 	rv = ishtp_cl_connect(cros_ish_cl);
409 	if (rv) {
410 		dev_err(cl_data_to_dev(client_data),
411 			"client connect fail\n");
412 		goto err_cl_unlink;
413 	}
414 
415 	ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
416 	return 0;
417 
418 err_cl_unlink:
419 	ishtp_cl_unlink(cros_ish_cl);
420 	return rv;
421 }
422 
423 /**
424  * cros_ish_deinit() - Deinit function for ISHTP client
425  * @cros_ish_cl: ISHTP client instance
426  *
427  * Unlink and free cros_ec client
428  */
429 static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
430 {
431 	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
432 	ishtp_cl_disconnect(cros_ish_cl);
433 	ishtp_cl_unlink(cros_ish_cl);
434 	ishtp_cl_flush_queues(cros_ish_cl);
435 
436 	/* Disband and free all Tx and Rx client-level rings */
437 	ishtp_cl_free(cros_ish_cl);
438 }
439 
440 /**
441  * prepare_cros_ec_rx() - Check & prepare receive buffer
442  * @ec_dev: CrOS EC MFD device.
443  * @in_msg: Incoming message buffer
444  * @msg: cros_ec command used to send & receive data
445  *
446  * Return: 0 for success, negative error code for failure.
447  *
448  * Check the received buffer. Convert to cros_ec_command format.
449  */
450 static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
451 			      const struct cros_ish_in_msg *in_msg,
452 			      struct cros_ec_command *msg)
453 {
454 	u8 sum = 0;
455 	int i, rv, offset;
456 
457 	/* Check response error code */
458 	msg->result = in_msg->ec_response.result;
459 	rv = cros_ec_check_result(ec_dev, msg);
460 	if (rv < 0)
461 		return rv;
462 
463 	if (in_msg->ec_response.data_len > msg->insize) {
464 		dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
465 			in_msg->ec_response.data_len, msg->insize);
466 		return -ENOSPC;
467 	}
468 
469 	/* Copy response packet payload and compute checksum */
470 	for (i = 0; i < sizeof(struct ec_host_response); i++)
471 		sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
472 
473 	offset = sizeof(struct cros_ish_in_msg);
474 	for (i = 0; i < in_msg->ec_response.data_len; i++)
475 		sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
476 
477 	if (sum) {
478 		dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
479 		return -EBADMSG;
480 	}
481 
482 	return 0;
483 }
484 
485 static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
486 				struct cros_ec_command *msg)
487 {
488 	int rv;
489 	struct ishtp_cl *cros_ish_cl = ec_dev->priv;
490 	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
491 	struct device *dev = cl_data_to_dev(client_data);
492 	struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
493 	struct cros_ish_out_msg *out_msg =
494 		(struct cros_ish_out_msg *)ec_dev->dout;
495 	size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
496 	size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
497 
498 	/* Sanity checks */
499 	if (in_size > ec_dev->din_size) {
500 		dev_err(dev,
501 			"Incoming payload size %zu is too large for ec_dev->din_size %d\n",
502 			in_size, ec_dev->din_size);
503 		return -EMSGSIZE;
504 	}
505 
506 	if (out_size > ec_dev->dout_size) {
507 		dev_err(dev,
508 			"Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
509 			out_size, ec_dev->dout_size);
510 		return -EMSGSIZE;
511 	}
512 
513 	/* Proceed only if reset-init is not in progress */
514 	if (!down_read_trylock(&init_lock)) {
515 		dev_warn(dev,
516 			 "Host is not ready to send messages to ISH. Try again\n");
517 		return -EAGAIN;
518 	}
519 
520 	/* Prepare the package to be sent over ISH TP */
521 	out_msg->hdr.channel = CROS_EC_COMMAND;
522 	out_msg->hdr.status = 0;
523 
524 	ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
525 	cros_ec_prepare_tx(ec_dev, msg);
526 	ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
527 
528 	dev_dbg(dev,
529 		"out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
530 		out_msg->ec_request.struct_version,
531 		out_msg->ec_request.checksum,
532 		out_msg->ec_request.command,
533 		out_msg->ec_request.command_version,
534 		out_msg->ec_request.data_len);
535 
536 	/* Send command to ISH EC firmware and read response */
537 	rv = ish_send(client_data,
538 		      (u8 *)out_msg, out_size,
539 		      (u8 *)in_msg, in_size);
540 	if (rv < 0)
541 		goto end_error;
542 
543 	rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
544 	if (rv)
545 		goto end_error;
546 
547 	rv = in_msg->ec_response.data_len;
548 
549 	dev_dbg(dev,
550 		"in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
551 		in_msg->ec_response.struct_version,
552 		in_msg->ec_response.checksum,
553 		in_msg->ec_response.result,
554 		in_msg->ec_response.data_len);
555 
556 end_error:
557 	if (msg->command == EC_CMD_REBOOT_EC)
558 		msleep(EC_REBOOT_DELAY_MS);
559 
560 	up_read(&init_lock);
561 
562 	return rv;
563 }
564 
565 static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
566 {
567 	struct cros_ec_device *ec_dev;
568 	struct device *dev = cl_data_to_dev(client_data);
569 
570 	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
571 	if (!ec_dev)
572 		return -ENOMEM;
573 
574 	client_data->ec_dev = ec_dev;
575 	dev->driver_data = ec_dev;
576 
577 	ec_dev->dev = dev;
578 	ec_dev->priv = client_data->cros_ish_cl;
579 	ec_dev->cmd_xfer = NULL;
580 	ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
581 	ec_dev->phys_name = dev_name(dev);
582 	ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
583 			   sizeof(struct ec_response_get_protocol_info);
584 	ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
585 
586 	return cros_ec_register(ec_dev);
587 }
588 
589 static void reset_handler(struct work_struct *work)
590 {
591 	int rv;
592 	struct device *dev;
593 	struct ishtp_cl *cros_ish_cl;
594 	struct ishtp_cl_device *cl_device;
595 	struct ishtp_cl_data *client_data =
596 		container_of(work, struct ishtp_cl_data, work_ishtp_reset);
597 
598 	/* Lock for reset to complete */
599 	down_write(&init_lock);
600 
601 	cros_ish_cl = client_data->cros_ish_cl;
602 	cl_device = client_data->cl_device;
603 
604 	/* Unlink, flush queues & start again */
605 	ishtp_cl_unlink(cros_ish_cl);
606 	ishtp_cl_flush_queues(cros_ish_cl);
607 	ishtp_cl_free(cros_ish_cl);
608 
609 	cros_ish_cl = ishtp_cl_allocate(cl_device);
610 	if (!cros_ish_cl) {
611 		up_write(&init_lock);
612 		return;
613 	}
614 
615 	ishtp_set_drvdata(cl_device, cros_ish_cl);
616 	ishtp_set_client_data(cros_ish_cl, client_data);
617 	client_data->cros_ish_cl = cros_ish_cl;
618 
619 	rv = cros_ish_init(cros_ish_cl);
620 	if (rv) {
621 		ishtp_cl_free(cros_ish_cl);
622 		dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
623 		up_write(&init_lock);
624 		return;
625 	}
626 
627 	/* Refresh ec_dev device pointers */
628 	client_data->ec_dev->priv = client_data->cros_ish_cl;
629 	dev = cl_data_to_dev(client_data);
630 	dev->driver_data = client_data->ec_dev;
631 
632 	dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
633 
634 	up_write(&init_lock);
635 }
636 
637 /**
638  * cros_ec_ishtp_probe() - ISHTP client driver probe callback
639  * @cl_device: ISHTP client device instance
640  *
641  * Return: 0 for success, negative error code for failure.
642  */
643 static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
644 {
645 	int rv;
646 	struct ishtp_cl *cros_ish_cl;
647 	struct ishtp_cl_data *client_data =
648 		devm_kzalloc(ishtp_device(cl_device),
649 			     sizeof(*client_data), GFP_KERNEL);
650 	if (!client_data)
651 		return -ENOMEM;
652 
653 	/* Lock for initialization to complete */
654 	down_write(&init_lock);
655 
656 	cros_ish_cl = ishtp_cl_allocate(cl_device);
657 	if (!cros_ish_cl) {
658 		rv = -ENOMEM;
659 		goto end_ishtp_cl_alloc_error;
660 	}
661 
662 	ishtp_set_drvdata(cl_device, cros_ish_cl);
663 	ishtp_set_client_data(cros_ish_cl, client_data);
664 	client_data->cros_ish_cl = cros_ish_cl;
665 	client_data->cl_device = cl_device;
666 
667 	init_waitqueue_head(&client_data->response.wait_queue);
668 
669 	INIT_WORK(&client_data->work_ishtp_reset,
670 		  reset_handler);
671 	INIT_WORK(&client_data->work_ec_evt,
672 		  ish_evt_handler);
673 
674 	rv = cros_ish_init(cros_ish_cl);
675 	if (rv)
676 		goto end_ishtp_cl_init_error;
677 
678 	ishtp_get_device(cl_device);
679 
680 	up_write(&init_lock);
681 
682 	/* Register croc_ec_dev mfd */
683 	rv = cros_ec_dev_init(client_data);
684 	if (rv) {
685 		down_write(&init_lock);
686 		goto end_cros_ec_dev_init_error;
687 	}
688 
689 	return 0;
690 
691 end_cros_ec_dev_init_error:
692 	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
693 	ishtp_cl_disconnect(cros_ish_cl);
694 	ishtp_cl_unlink(cros_ish_cl);
695 	ishtp_cl_flush_queues(cros_ish_cl);
696 	ishtp_put_device(cl_device);
697 end_ishtp_cl_init_error:
698 	ishtp_cl_free(cros_ish_cl);
699 end_ishtp_cl_alloc_error:
700 	up_write(&init_lock);
701 	return rv;
702 }
703 
704 /**
705  * cros_ec_ishtp_remove() - ISHTP client driver remove callback
706  * @cl_device: ISHTP client device instance
707  *
708  * Return: 0
709  */
710 static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
711 {
712 	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
713 	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
714 
715 	cancel_work_sync(&client_data->work_ishtp_reset);
716 	cancel_work_sync(&client_data->work_ec_evt);
717 	cros_ish_deinit(cros_ish_cl);
718 	ishtp_put_device(cl_device);
719 
720 	return 0;
721 }
722 
723 /**
724  * cros_ec_ishtp_reset() - ISHTP client driver reset callback
725  * @cl_device: ISHTP client device instance
726  *
727  * Return: 0
728  */
729 static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
730 {
731 	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
732 	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
733 
734 	schedule_work(&client_data->work_ishtp_reset);
735 
736 	return 0;
737 }
738 
739 /**
740  * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
741  * @device: device instance
742  *
743  * Return: 0 for success, negative error code for failure.
744  */
745 static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
746 {
747 	struct ishtp_cl_device *cl_device = ishtp_dev_to_cl_device(device);
748 	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
749 	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
750 
751 	return cros_ec_suspend(client_data->ec_dev);
752 }
753 
754 /**
755  * cros_ec_ishtp_resume() - ISHTP client driver resume callback
756  * @device: device instance
757  *
758  * Return: 0 for success, negative error code for failure.
759  */
760 static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
761 {
762 	struct ishtp_cl_device *cl_device = ishtp_dev_to_cl_device(device);
763 	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
764 	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
765 
766 	return cros_ec_resume(client_data->ec_dev);
767 }
768 
769 static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
770 			 cros_ec_ishtp_resume);
771 
772 static struct ishtp_cl_driver	cros_ec_ishtp_driver = {
773 	.name = "cros_ec_ishtp",
774 	.guid = &cros_ish_guid,
775 	.probe = cros_ec_ishtp_probe,
776 	.remove = cros_ec_ishtp_remove,
777 	.reset = cros_ec_ishtp_reset,
778 	.driver = {
779 		.pm = &cros_ec_ishtp_pm_ops,
780 	},
781 };
782 
783 static int __init cros_ec_ishtp_mod_init(void)
784 {
785 	return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
786 }
787 
788 static void __exit cros_ec_ishtp_mod_exit(void)
789 {
790 	ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
791 }
792 
793 module_init(cros_ec_ishtp_mod_init);
794 module_exit(cros_ec_ishtp_mod_exit);
795 
796 MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
797 MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
798 
799 MODULE_LICENSE("GPL v2");
800 MODULE_ALIAS("ishtp:*");
801