1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2016-2017, Linaro Ltd
4  */
5 
6 #include <linux/idr.h>
7 #include <linux/interrupt.h>
8 #include <linux/io.h>
9 #include <linux/list.h>
10 #include <linux/mfd/syscon.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14 #include <linux/of_irq.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17 #include <linux/rpmsg.h>
18 #include <linux/sizes.h>
19 #include <linux/slab.h>
20 #include <linux/workqueue.h>
21 #include <linux/mailbox_client.h>
22 
23 #include "rpmsg_internal.h"
24 #include "qcom_glink_native.h"
25 
26 #define GLINK_NAME_SIZE		32
27 #define GLINK_VERSION_1		1
28 
29 #define RPM_GLINK_CID_MIN	1
30 #define RPM_GLINK_CID_MAX	65536
31 
32 struct glink_msg {
33 	__le16 cmd;
34 	__le16 param1;
35 	__le32 param2;
36 	u8 data[];
37 } __packed;
38 
39 /**
40  * struct glink_defer_cmd - deferred incoming control message
41  * @node:	list node
42  * @msg:	message header
43  * @data:	payload of the message
44  *
45  * Copy of a received control message, to be added to @rx_queue and processed
46  * by @rx_work of @qcom_glink.
47  */
48 struct glink_defer_cmd {
49 	struct list_head node;
50 
51 	struct glink_msg msg;
52 	u8 data[];
53 };
54 
55 /**
56  * struct glink_core_rx_intent - RX intent
57  * RX intent
58  *
59  * @data: pointer to the data (may be NULL for zero-copy)
60  * @id: remote or local intent ID
61  * @size: size of the original intent (do not modify)
62  * @reuse: To mark if the intent can be reused after first use
63  * @in_use: To mark if intent is already in use for the channel
64  * @offset: next write offset (initially 0)
65  * @node:	list node
66  */
67 struct glink_core_rx_intent {
68 	void *data;
69 	u32 id;
70 	size_t size;
71 	bool reuse;
72 	bool in_use;
73 	u32 offset;
74 
75 	struct list_head node;
76 };
77 
78 /**
79  * struct qcom_glink - driver context, relates to one remote subsystem
80  * @dev:	reference to the associated struct device
81  * @mbox_client: mailbox client
82  * @mbox_chan:  mailbox channel
83  * @rx_pipe:	pipe object for receive FIFO
84  * @tx_pipe:	pipe object for transmit FIFO
85  * @irq:	IRQ for signaling incoming events
86  * @rx_work:	worker for handling received control messages
87  * @rx_lock:	protects the @rx_queue
88  * @rx_queue:	queue of received control messages to be processed in @rx_work
89  * @tx_lock:	synchronizes operations on the tx fifo
90  * @idr_lock:	synchronizes @lcids and @rcids modifications
91  * @lcids:	idr of all channels with a known local channel id
92  * @rcids:	idr of all channels with a known remote channel id
93  * @features:	remote features
94  * @intentless:	flag to indicate that there is no intent
95  */
96 struct qcom_glink {
97 	struct device *dev;
98 
99 	const char *name;
100 
101 	struct mbox_client mbox_client;
102 	struct mbox_chan *mbox_chan;
103 
104 	struct qcom_glink_pipe *rx_pipe;
105 	struct qcom_glink_pipe *tx_pipe;
106 
107 	int irq;
108 
109 	struct work_struct rx_work;
110 	spinlock_t rx_lock;
111 	struct list_head rx_queue;
112 
113 	spinlock_t tx_lock;
114 
115 	spinlock_t idr_lock;
116 	struct idr lcids;
117 	struct idr rcids;
118 	unsigned long features;
119 
120 	bool intentless;
121 };
122 
123 enum {
124 	GLINK_STATE_CLOSED,
125 	GLINK_STATE_OPENING,
126 	GLINK_STATE_OPEN,
127 	GLINK_STATE_CLOSING,
128 };
129 
130 /**
131  * struct glink_channel - internal representation of a channel
132  * @rpdev:	rpdev reference, only used for primary endpoints
133  * @ept:	rpmsg endpoint this channel is associated with
134  * @glink:	qcom_glink context handle
135  * @refcount:	refcount for the channel object
136  * @recv_lock:	guard for @ept.cb
137  * @name:	unique channel name/identifier
138  * @lcid:	channel id, in local space
139  * @rcid:	channel id, in remote space
140  * @intent_lock: lock for protection of @liids, @riids
141  * @liids:	idr of all local intents
142  * @riids:	idr of all remote intents
143  * @intent_work: worker responsible for transmitting rx_done packets
144  * @done_intents: list of intents that needs to be announced rx_done
145  * @buf:	receive buffer, for gathering fragments
146  * @buf_offset:	write offset in @buf
147  * @buf_size:	size of current @buf
148  * @open_ack:	completed once remote has acked the open-request
149  * @open_req:	completed once open-request has been received
150  * @intent_req_lock: Synchronises multiple intent requests
151  * @intent_req_result: Result of intent request
152  * @intent_req_comp: Completion for intent_req signalling
153  */
154 struct glink_channel {
155 	struct rpmsg_endpoint ept;
156 
157 	struct rpmsg_device *rpdev;
158 	struct qcom_glink *glink;
159 
160 	struct kref refcount;
161 
162 	spinlock_t recv_lock;
163 
164 	char *name;
165 	unsigned int lcid;
166 	unsigned int rcid;
167 
168 	spinlock_t intent_lock;
169 	struct idr liids;
170 	struct idr riids;
171 	struct work_struct intent_work;
172 	struct list_head done_intents;
173 
174 	struct glink_core_rx_intent *buf;
175 	int buf_offset;
176 	int buf_size;
177 
178 	struct completion open_ack;
179 	struct completion open_req;
180 
181 	struct mutex intent_req_lock;
182 	bool intent_req_result;
183 	struct completion intent_req_comp;
184 };
185 
186 #define to_glink_channel(_ept) container_of(_ept, struct glink_channel, ept)
187 
188 static const struct rpmsg_endpoint_ops glink_endpoint_ops;
189 
190 #define RPM_CMD_VERSION			0
191 #define RPM_CMD_VERSION_ACK		1
192 #define RPM_CMD_OPEN			2
193 #define RPM_CMD_CLOSE			3
194 #define RPM_CMD_OPEN_ACK		4
195 #define RPM_CMD_INTENT			5
196 #define RPM_CMD_RX_DONE			6
197 #define RPM_CMD_RX_INTENT_REQ		7
198 #define RPM_CMD_RX_INTENT_REQ_ACK	8
199 #define RPM_CMD_TX_DATA			9
200 #define RPM_CMD_CLOSE_ACK		11
201 #define RPM_CMD_TX_DATA_CONT		12
202 #define RPM_CMD_READ_NOTIF		13
203 #define RPM_CMD_RX_DONE_W_REUSE		14
204 
205 #define GLINK_FEATURE_INTENTLESS	BIT(1)
206 
207 static void qcom_glink_rx_done_work(struct work_struct *work);
208 
209 static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
210 						      const char *name)
211 {
212 	struct glink_channel *channel;
213 
214 	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
215 	if (!channel)
216 		return ERR_PTR(-ENOMEM);
217 
218 	/* Setup glink internal glink_channel data */
219 	spin_lock_init(&channel->recv_lock);
220 	spin_lock_init(&channel->intent_lock);
221 	mutex_init(&channel->intent_req_lock);
222 
223 	channel->glink = glink;
224 	channel->name = kstrdup(name, GFP_KERNEL);
225 
226 	init_completion(&channel->open_req);
227 	init_completion(&channel->open_ack);
228 	init_completion(&channel->intent_req_comp);
229 
230 	INIT_LIST_HEAD(&channel->done_intents);
231 	INIT_WORK(&channel->intent_work, qcom_glink_rx_done_work);
232 
233 	idr_init(&channel->liids);
234 	idr_init(&channel->riids);
235 	kref_init(&channel->refcount);
236 
237 	return channel;
238 }
239 
240 static void qcom_glink_channel_release(struct kref *ref)
241 {
242 	struct glink_channel *channel = container_of(ref, struct glink_channel,
243 						     refcount);
244 	struct glink_core_rx_intent *intent;
245 	struct glink_core_rx_intent *tmp;
246 	unsigned long flags;
247 	int iid;
248 
249 	/* cancel pending rx_done work */
250 	cancel_work_sync(&channel->intent_work);
251 
252 	spin_lock_irqsave(&channel->intent_lock, flags);
253 	/* Free all non-reuse intents pending rx_done work */
254 	list_for_each_entry_safe(intent, tmp, &channel->done_intents, node) {
255 		if (!intent->reuse) {
256 			kfree(intent->data);
257 			kfree(intent);
258 		}
259 	}
260 
261 	idr_for_each_entry(&channel->liids, tmp, iid) {
262 		kfree(tmp->data);
263 		kfree(tmp);
264 	}
265 	idr_destroy(&channel->liids);
266 
267 	idr_for_each_entry(&channel->riids, tmp, iid)
268 		kfree(tmp);
269 	idr_destroy(&channel->riids);
270 	spin_unlock_irqrestore(&channel->intent_lock, flags);
271 
272 	kfree(channel->name);
273 	kfree(channel);
274 }
275 
276 static size_t qcom_glink_rx_avail(struct qcom_glink *glink)
277 {
278 	return glink->rx_pipe->avail(glink->rx_pipe);
279 }
280 
281 static void qcom_glink_rx_peak(struct qcom_glink *glink,
282 			       void *data, unsigned int offset, size_t count)
283 {
284 	glink->rx_pipe->peak(glink->rx_pipe, data, offset, count);
285 }
286 
287 static void qcom_glink_rx_advance(struct qcom_glink *glink, size_t count)
288 {
289 	glink->rx_pipe->advance(glink->rx_pipe, count);
290 }
291 
292 static size_t qcom_glink_tx_avail(struct qcom_glink *glink)
293 {
294 	return glink->tx_pipe->avail(glink->tx_pipe);
295 }
296 
297 static void qcom_glink_tx_write(struct qcom_glink *glink,
298 				const void *hdr, size_t hlen,
299 				const void *data, size_t dlen)
300 {
301 	glink->tx_pipe->write(glink->tx_pipe, hdr, hlen, data, dlen);
302 }
303 
304 static int qcom_glink_tx(struct qcom_glink *glink,
305 			 const void *hdr, size_t hlen,
306 			 const void *data, size_t dlen, bool wait)
307 {
308 	unsigned int tlen = hlen + dlen;
309 	unsigned long flags;
310 	int ret = 0;
311 
312 	/* Reject packets that are too big */
313 	if (tlen >= glink->tx_pipe->length)
314 		return -EINVAL;
315 
316 	spin_lock_irqsave(&glink->tx_lock, flags);
317 
318 	while (qcom_glink_tx_avail(glink) < tlen) {
319 		if (!wait) {
320 			ret = -EAGAIN;
321 			goto out;
322 		}
323 
324 		/* Wait without holding the tx_lock */
325 		spin_unlock_irqrestore(&glink->tx_lock, flags);
326 
327 		usleep_range(10000, 15000);
328 
329 		spin_lock_irqsave(&glink->tx_lock, flags);
330 	}
331 
332 	qcom_glink_tx_write(glink, hdr, hlen, data, dlen);
333 
334 	mbox_send_message(glink->mbox_chan, NULL);
335 	mbox_client_txdone(glink->mbox_chan, 0);
336 
337 out:
338 	spin_unlock_irqrestore(&glink->tx_lock, flags);
339 
340 	return ret;
341 }
342 
343 static int qcom_glink_send_version(struct qcom_glink *glink)
344 {
345 	struct glink_msg msg;
346 
347 	msg.cmd = cpu_to_le16(RPM_CMD_VERSION);
348 	msg.param1 = cpu_to_le16(GLINK_VERSION_1);
349 	msg.param2 = cpu_to_le32(glink->features);
350 
351 	return qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
352 }
353 
354 static void qcom_glink_send_version_ack(struct qcom_glink *glink)
355 {
356 	struct glink_msg msg;
357 
358 	msg.cmd = cpu_to_le16(RPM_CMD_VERSION_ACK);
359 	msg.param1 = cpu_to_le16(GLINK_VERSION_1);
360 	msg.param2 = cpu_to_le32(glink->features);
361 
362 	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
363 }
364 
365 static void qcom_glink_send_open_ack(struct qcom_glink *glink,
366 				     struct glink_channel *channel)
367 {
368 	struct glink_msg msg;
369 
370 	msg.cmd = cpu_to_le16(RPM_CMD_OPEN_ACK);
371 	msg.param1 = cpu_to_le16(channel->rcid);
372 	msg.param2 = cpu_to_le32(0);
373 
374 	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
375 }
376 
377 static void qcom_glink_handle_intent_req_ack(struct qcom_glink *glink,
378 					     unsigned int cid, bool granted)
379 {
380 	struct glink_channel *channel;
381 	unsigned long flags;
382 
383 	spin_lock_irqsave(&glink->idr_lock, flags);
384 	channel = idr_find(&glink->rcids, cid);
385 	spin_unlock_irqrestore(&glink->idr_lock, flags);
386 	if (!channel) {
387 		dev_err(glink->dev, "unable to find channel\n");
388 		return;
389 	}
390 
391 	channel->intent_req_result = granted;
392 	complete(&channel->intent_req_comp);
393 }
394 
395 /**
396  * qcom_glink_send_open_req() - send a RPM_CMD_OPEN request to the remote
397  * @glink: Ptr to the glink edge
398  * @channel: Ptr to the channel that the open req is sent
399  *
400  * Allocates a local channel id and sends a RPM_CMD_OPEN message to the remote.
401  * Will return with refcount held, regardless of outcome.
402  *
403  * Returns 0 on success, negative errno otherwise.
404  */
405 static int qcom_glink_send_open_req(struct qcom_glink *glink,
406 				    struct glink_channel *channel)
407 {
408 	struct {
409 		struct glink_msg msg;
410 		u8 name[GLINK_NAME_SIZE];
411 	} __packed req;
412 	int name_len = strlen(channel->name) + 1;
413 	int req_len = ALIGN(sizeof(req.msg) + name_len, 8);
414 	int ret;
415 	unsigned long flags;
416 
417 	kref_get(&channel->refcount);
418 
419 	spin_lock_irqsave(&glink->idr_lock, flags);
420 	ret = idr_alloc_cyclic(&glink->lcids, channel,
421 			       RPM_GLINK_CID_MIN, RPM_GLINK_CID_MAX,
422 			       GFP_ATOMIC);
423 	spin_unlock_irqrestore(&glink->idr_lock, flags);
424 	if (ret < 0)
425 		return ret;
426 
427 	channel->lcid = ret;
428 
429 	req.msg.cmd = cpu_to_le16(RPM_CMD_OPEN);
430 	req.msg.param1 = cpu_to_le16(channel->lcid);
431 	req.msg.param2 = cpu_to_le32(name_len);
432 	strcpy(req.name, channel->name);
433 
434 	ret = qcom_glink_tx(glink, &req, req_len, NULL, 0, true);
435 	if (ret)
436 		goto remove_idr;
437 
438 	return 0;
439 
440 remove_idr:
441 	spin_lock_irqsave(&glink->idr_lock, flags);
442 	idr_remove(&glink->lcids, channel->lcid);
443 	channel->lcid = 0;
444 	spin_unlock_irqrestore(&glink->idr_lock, flags);
445 
446 	return ret;
447 }
448 
449 static void qcom_glink_send_close_req(struct qcom_glink *glink,
450 				      struct glink_channel *channel)
451 {
452 	struct glink_msg req;
453 
454 	req.cmd = cpu_to_le16(RPM_CMD_CLOSE);
455 	req.param1 = cpu_to_le16(channel->lcid);
456 	req.param2 = 0;
457 
458 	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
459 }
460 
461 static void qcom_glink_send_close_ack(struct qcom_glink *glink,
462 				      unsigned int rcid)
463 {
464 	struct glink_msg req;
465 
466 	req.cmd = cpu_to_le16(RPM_CMD_CLOSE_ACK);
467 	req.param1 = cpu_to_le16(rcid);
468 	req.param2 = 0;
469 
470 	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
471 }
472 
473 static void qcom_glink_rx_done_work(struct work_struct *work)
474 {
475 	struct glink_channel *channel = container_of(work, struct glink_channel,
476 						     intent_work);
477 	struct qcom_glink *glink = channel->glink;
478 	struct glink_core_rx_intent *intent, *tmp;
479 	struct {
480 		u16 id;
481 		u16 lcid;
482 		u32 liid;
483 	} __packed cmd;
484 
485 	unsigned int cid = channel->lcid;
486 	unsigned int iid;
487 	bool reuse;
488 	unsigned long flags;
489 
490 	spin_lock_irqsave(&channel->intent_lock, flags);
491 	list_for_each_entry_safe(intent, tmp, &channel->done_intents, node) {
492 		list_del(&intent->node);
493 		spin_unlock_irqrestore(&channel->intent_lock, flags);
494 		iid = intent->id;
495 		reuse = intent->reuse;
496 
497 		cmd.id = reuse ? RPM_CMD_RX_DONE_W_REUSE : RPM_CMD_RX_DONE;
498 		cmd.lcid = cid;
499 		cmd.liid = iid;
500 
501 		qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
502 		if (!reuse) {
503 			kfree(intent->data);
504 			kfree(intent);
505 		}
506 		spin_lock_irqsave(&channel->intent_lock, flags);
507 	}
508 	spin_unlock_irqrestore(&channel->intent_lock, flags);
509 }
510 
511 static void qcom_glink_rx_done(struct qcom_glink *glink,
512 			       struct glink_channel *channel,
513 			       struct glink_core_rx_intent *intent)
514 {
515 	/* We don't send RX_DONE to intentless systems */
516 	if (glink->intentless) {
517 		kfree(intent->data);
518 		kfree(intent);
519 		return;
520 	}
521 
522 	/* Take it off the tree of receive intents */
523 	if (!intent->reuse) {
524 		spin_lock(&channel->intent_lock);
525 		idr_remove(&channel->liids, intent->id);
526 		spin_unlock(&channel->intent_lock);
527 	}
528 
529 	/* Schedule the sending of a rx_done indication */
530 	spin_lock(&channel->intent_lock);
531 	list_add_tail(&intent->node, &channel->done_intents);
532 	spin_unlock(&channel->intent_lock);
533 
534 	schedule_work(&channel->intent_work);
535 }
536 
537 /**
538  * qcom_glink_receive_version() - receive version/features from remote system
539  *
540  * @glink:	pointer to transport interface
541  * @version:	remote version
542  * @features:	remote features
543  *
544  * This function is called in response to a remote-initiated version/feature
545  * negotiation sequence.
546  */
547 static void qcom_glink_receive_version(struct qcom_glink *glink,
548 				       u32 version,
549 				       u32 features)
550 {
551 	switch (version) {
552 	case 0:
553 		break;
554 	case GLINK_VERSION_1:
555 		glink->features &= features;
556 		fallthrough;
557 	default:
558 		qcom_glink_send_version_ack(glink);
559 		break;
560 	}
561 }
562 
563 /**
564  * qcom_glink_receive_version_ack() - receive negotiation ack from remote system
565  *
566  * @glink:	pointer to transport interface
567  * @version:	remote version response
568  * @features:	remote features response
569  *
570  * This function is called in response to a local-initiated version/feature
571  * negotiation sequence and is the counter-offer from the remote side based
572  * upon the initial version and feature set requested.
573  */
574 static void qcom_glink_receive_version_ack(struct qcom_glink *glink,
575 					   u32 version,
576 					   u32 features)
577 {
578 	switch (version) {
579 	case 0:
580 		/* Version negotiation failed */
581 		break;
582 	case GLINK_VERSION_1:
583 		if (features == glink->features)
584 			break;
585 
586 		glink->features &= features;
587 		fallthrough;
588 	default:
589 		qcom_glink_send_version(glink);
590 		break;
591 	}
592 }
593 
594 /**
595  * qcom_glink_send_intent_req_ack() - convert an rx intent request ack cmd to
596  * 	wire format and transmit
597  * @glink:	The transport to transmit on.
598  * @channel:	The glink channel
599  * @granted:	The request response to encode.
600  *
601  * Return: 0 on success or standard Linux error code.
602  */
603 static int qcom_glink_send_intent_req_ack(struct qcom_glink *glink,
604 					  struct glink_channel *channel,
605 					  bool granted)
606 {
607 	struct glink_msg msg;
608 
609 	msg.cmd = cpu_to_le16(RPM_CMD_RX_INTENT_REQ_ACK);
610 	msg.param1 = cpu_to_le16(channel->lcid);
611 	msg.param2 = cpu_to_le32(granted);
612 
613 	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
614 
615 	return 0;
616 }
617 
618 /**
619  * qcom_glink_advertise_intent - convert an rx intent cmd to wire format and
620  *			   transmit
621  * @glink:	The transport to transmit on.
622  * @channel:	The local channel
623  * @intent:	The intent to pass on to remote.
624  *
625  * Return: 0 on success or standard Linux error code.
626  */
627 static int qcom_glink_advertise_intent(struct qcom_glink *glink,
628 				       struct glink_channel *channel,
629 				       struct glink_core_rx_intent *intent)
630 {
631 	struct command {
632 		__le16 id;
633 		__le16 lcid;
634 		__le32 count;
635 		__le32 size;
636 		__le32 liid;
637 	} __packed;
638 	struct command cmd;
639 
640 	cmd.id = cpu_to_le16(RPM_CMD_INTENT);
641 	cmd.lcid = cpu_to_le16(channel->lcid);
642 	cmd.count = cpu_to_le32(1);
643 	cmd.size = cpu_to_le32(intent->size);
644 	cmd.liid = cpu_to_le32(intent->id);
645 
646 	qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
647 
648 	return 0;
649 }
650 
651 static struct glink_core_rx_intent *
652 qcom_glink_alloc_intent(struct qcom_glink *glink,
653 			struct glink_channel *channel,
654 			size_t size,
655 			bool reuseable)
656 {
657 	struct glink_core_rx_intent *intent;
658 	int ret;
659 	unsigned long flags;
660 
661 	intent = kzalloc(sizeof(*intent), GFP_KERNEL);
662 	if (!intent)
663 		return NULL;
664 
665 	intent->data = kzalloc(size, GFP_KERNEL);
666 	if (!intent->data)
667 		goto free_intent;
668 
669 	spin_lock_irqsave(&channel->intent_lock, flags);
670 	ret = idr_alloc_cyclic(&channel->liids, intent, 1, -1, GFP_ATOMIC);
671 	if (ret < 0) {
672 		spin_unlock_irqrestore(&channel->intent_lock, flags);
673 		goto free_data;
674 	}
675 	spin_unlock_irqrestore(&channel->intent_lock, flags);
676 
677 	intent->id = ret;
678 	intent->size = size;
679 	intent->reuse = reuseable;
680 
681 	return intent;
682 
683 free_data:
684 	kfree(intent->data);
685 free_intent:
686 	kfree(intent);
687 	return NULL;
688 }
689 
690 static void qcom_glink_handle_rx_done(struct qcom_glink *glink,
691 				      u32 cid, uint32_t iid,
692 				      bool reuse)
693 {
694 	struct glink_core_rx_intent *intent;
695 	struct glink_channel *channel;
696 	unsigned long flags;
697 
698 	spin_lock_irqsave(&glink->idr_lock, flags);
699 	channel = idr_find(&glink->rcids, cid);
700 	spin_unlock_irqrestore(&glink->idr_lock, flags);
701 	if (!channel) {
702 		dev_err(glink->dev, "invalid channel id received\n");
703 		return;
704 	}
705 
706 	spin_lock_irqsave(&channel->intent_lock, flags);
707 	intent = idr_find(&channel->riids, iid);
708 
709 	if (!intent) {
710 		spin_unlock_irqrestore(&channel->intent_lock, flags);
711 		dev_err(glink->dev, "invalid intent id received\n");
712 		return;
713 	}
714 
715 	intent->in_use = false;
716 
717 	if (!reuse) {
718 		idr_remove(&channel->riids, intent->id);
719 		kfree(intent);
720 	}
721 	spin_unlock_irqrestore(&channel->intent_lock, flags);
722 }
723 
724 /**
725  * qcom_glink_handle_intent_req() - Receive a request for rx_intent
726  *					    from remote side
727  * @glink:      Pointer to the transport interface
728  * @cid:	Remote channel ID
729  * @size:	size of the intent
730  *
731  * The function searches for the local channel to which the request for
732  * rx_intent has arrived and allocates and notifies the remote back
733  */
734 static void qcom_glink_handle_intent_req(struct qcom_glink *glink,
735 					 u32 cid, size_t size)
736 {
737 	struct glink_core_rx_intent *intent;
738 	struct glink_channel *channel;
739 	unsigned long flags;
740 
741 	spin_lock_irqsave(&glink->idr_lock, flags);
742 	channel = idr_find(&glink->rcids, cid);
743 	spin_unlock_irqrestore(&glink->idr_lock, flags);
744 
745 	if (!channel) {
746 		pr_err("%s channel not found for cid %d\n", __func__, cid);
747 		return;
748 	}
749 
750 	intent = qcom_glink_alloc_intent(glink, channel, size, false);
751 	if (intent)
752 		qcom_glink_advertise_intent(glink, channel, intent);
753 
754 	qcom_glink_send_intent_req_ack(glink, channel, !!intent);
755 }
756 
757 static int qcom_glink_rx_defer(struct qcom_glink *glink, size_t extra)
758 {
759 	struct glink_defer_cmd *dcmd;
760 
761 	extra = ALIGN(extra, 8);
762 
763 	if (qcom_glink_rx_avail(glink) < sizeof(struct glink_msg) + extra) {
764 		dev_dbg(glink->dev, "Insufficient data in rx fifo");
765 		return -ENXIO;
766 	}
767 
768 	dcmd = kzalloc(sizeof(*dcmd) + extra, GFP_ATOMIC);
769 	if (!dcmd)
770 		return -ENOMEM;
771 
772 	INIT_LIST_HEAD(&dcmd->node);
773 
774 	qcom_glink_rx_peak(glink, &dcmd->msg, 0, sizeof(dcmd->msg) + extra);
775 
776 	spin_lock(&glink->rx_lock);
777 	list_add_tail(&dcmd->node, &glink->rx_queue);
778 	spin_unlock(&glink->rx_lock);
779 
780 	schedule_work(&glink->rx_work);
781 	qcom_glink_rx_advance(glink, sizeof(dcmd->msg) + extra);
782 
783 	return 0;
784 }
785 
786 static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
787 {
788 	struct glink_core_rx_intent *intent;
789 	struct glink_channel *channel;
790 	struct {
791 		struct glink_msg msg;
792 		__le32 chunk_size;
793 		__le32 left_size;
794 	} __packed hdr;
795 	unsigned int chunk_size;
796 	unsigned int left_size;
797 	unsigned int rcid;
798 	unsigned int liid;
799 	int ret = 0;
800 	unsigned long flags;
801 
802 	if (avail < sizeof(hdr)) {
803 		dev_dbg(glink->dev, "Not enough data in fifo\n");
804 		return -EAGAIN;
805 	}
806 
807 	qcom_glink_rx_peak(glink, &hdr, 0, sizeof(hdr));
808 	chunk_size = le32_to_cpu(hdr.chunk_size);
809 	left_size = le32_to_cpu(hdr.left_size);
810 
811 	if (avail < sizeof(hdr) + chunk_size) {
812 		dev_dbg(glink->dev, "Payload not yet in fifo\n");
813 		return -EAGAIN;
814 	}
815 
816 	rcid = le16_to_cpu(hdr.msg.param1);
817 	spin_lock_irqsave(&glink->idr_lock, flags);
818 	channel = idr_find(&glink->rcids, rcid);
819 	spin_unlock_irqrestore(&glink->idr_lock, flags);
820 	if (!channel) {
821 		dev_dbg(glink->dev, "Data on non-existing channel\n");
822 
823 		/* Drop the message */
824 		goto advance_rx;
825 	}
826 
827 	if (glink->intentless) {
828 		/* Might have an ongoing, fragmented, message to append */
829 		if (!channel->buf) {
830 			intent = kzalloc(sizeof(*intent), GFP_ATOMIC);
831 			if (!intent)
832 				return -ENOMEM;
833 
834 			intent->data = kmalloc(chunk_size + left_size,
835 					       GFP_ATOMIC);
836 			if (!intent->data) {
837 				kfree(intent);
838 				return -ENOMEM;
839 			}
840 
841 			intent->id = 0xbabababa;
842 			intent->size = chunk_size + left_size;
843 			intent->offset = 0;
844 
845 			channel->buf = intent;
846 		} else {
847 			intent = channel->buf;
848 		}
849 	} else {
850 		liid = le32_to_cpu(hdr.msg.param2);
851 
852 		spin_lock_irqsave(&channel->intent_lock, flags);
853 		intent = idr_find(&channel->liids, liid);
854 		spin_unlock_irqrestore(&channel->intent_lock, flags);
855 
856 		if (!intent) {
857 			dev_err(glink->dev,
858 				"no intent found for channel %s intent %d",
859 				channel->name, liid);
860 			ret = -ENOENT;
861 			goto advance_rx;
862 		}
863 	}
864 
865 	if (intent->size - intent->offset < chunk_size) {
866 		dev_err(glink->dev, "Insufficient space in intent\n");
867 
868 		/* The packet header lied, drop payload */
869 		goto advance_rx;
870 	}
871 
872 	qcom_glink_rx_peak(glink, intent->data + intent->offset,
873 			   sizeof(hdr), chunk_size);
874 	intent->offset += chunk_size;
875 
876 	/* Handle message when no fragments remain to be received */
877 	if (!left_size) {
878 		spin_lock(&channel->recv_lock);
879 		if (channel->ept.cb) {
880 			channel->ept.cb(channel->ept.rpdev,
881 					intent->data,
882 					intent->offset,
883 					channel->ept.priv,
884 					RPMSG_ADDR_ANY);
885 		}
886 		spin_unlock(&channel->recv_lock);
887 
888 		intent->offset = 0;
889 		channel->buf = NULL;
890 
891 		qcom_glink_rx_done(glink, channel, intent);
892 	}
893 
894 advance_rx:
895 	qcom_glink_rx_advance(glink, ALIGN(sizeof(hdr) + chunk_size, 8));
896 
897 	return ret;
898 }
899 
900 static void qcom_glink_handle_intent(struct qcom_glink *glink,
901 				     unsigned int cid,
902 				     unsigned int count,
903 				     size_t avail)
904 {
905 	struct glink_core_rx_intent *intent;
906 	struct glink_channel *channel;
907 	struct intent_pair {
908 		__le32 size;
909 		__le32 iid;
910 	};
911 
912 	struct {
913 		struct glink_msg msg;
914 		struct intent_pair intents[];
915 	} __packed * msg;
916 
917 	const size_t msglen = struct_size(msg, intents, count);
918 	int ret;
919 	int i;
920 	unsigned long flags;
921 
922 	if (avail < msglen) {
923 		dev_dbg(glink->dev, "Not enough data in fifo\n");
924 		return;
925 	}
926 
927 	spin_lock_irqsave(&glink->idr_lock, flags);
928 	channel = idr_find(&glink->rcids, cid);
929 	spin_unlock_irqrestore(&glink->idr_lock, flags);
930 	if (!channel) {
931 		dev_err(glink->dev, "intents for non-existing channel\n");
932 		return;
933 	}
934 
935 	msg = kmalloc(msglen, GFP_ATOMIC);
936 	if (!msg)
937 		return;
938 
939 	qcom_glink_rx_peak(glink, msg, 0, msglen);
940 
941 	for (i = 0; i < count; ++i) {
942 		intent = kzalloc(sizeof(*intent), GFP_ATOMIC);
943 		if (!intent)
944 			break;
945 
946 		intent->id = le32_to_cpu(msg->intents[i].iid);
947 		intent->size = le32_to_cpu(msg->intents[i].size);
948 
949 		spin_lock_irqsave(&channel->intent_lock, flags);
950 		ret = idr_alloc(&channel->riids, intent,
951 				intent->id, intent->id + 1, GFP_ATOMIC);
952 		spin_unlock_irqrestore(&channel->intent_lock, flags);
953 
954 		if (ret < 0)
955 			dev_err(glink->dev, "failed to store remote intent\n");
956 	}
957 
958 	kfree(msg);
959 	qcom_glink_rx_advance(glink, ALIGN(msglen, 8));
960 }
961 
962 static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
963 {
964 	struct glink_channel *channel;
965 
966 	spin_lock(&glink->idr_lock);
967 	channel = idr_find(&glink->lcids, lcid);
968 	spin_unlock(&glink->idr_lock);
969 	if (!channel) {
970 		dev_err(glink->dev, "Invalid open ack packet\n");
971 		return -EINVAL;
972 	}
973 
974 	complete_all(&channel->open_ack);
975 
976 	return 0;
977 }
978 
979 static irqreturn_t qcom_glink_native_intr(int irq, void *data)
980 {
981 	struct qcom_glink *glink = data;
982 	struct glink_msg msg;
983 	unsigned int param1;
984 	unsigned int param2;
985 	unsigned int avail;
986 	unsigned int cmd;
987 	int ret = 0;
988 
989 	for (;;) {
990 		avail = qcom_glink_rx_avail(glink);
991 		if (avail < sizeof(msg))
992 			break;
993 
994 		qcom_glink_rx_peak(glink, &msg, 0, sizeof(msg));
995 
996 		cmd = le16_to_cpu(msg.cmd);
997 		param1 = le16_to_cpu(msg.param1);
998 		param2 = le32_to_cpu(msg.param2);
999 
1000 		switch (cmd) {
1001 		case RPM_CMD_VERSION:
1002 		case RPM_CMD_VERSION_ACK:
1003 		case RPM_CMD_CLOSE:
1004 		case RPM_CMD_CLOSE_ACK:
1005 		case RPM_CMD_RX_INTENT_REQ:
1006 			ret = qcom_glink_rx_defer(glink, 0);
1007 			break;
1008 		case RPM_CMD_OPEN_ACK:
1009 			ret = qcom_glink_rx_open_ack(glink, param1);
1010 			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
1011 			break;
1012 		case RPM_CMD_OPEN:
1013 			ret = qcom_glink_rx_defer(glink, param2);
1014 			break;
1015 		case RPM_CMD_TX_DATA:
1016 		case RPM_CMD_TX_DATA_CONT:
1017 			ret = qcom_glink_rx_data(glink, avail);
1018 			break;
1019 		case RPM_CMD_READ_NOTIF:
1020 			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
1021 
1022 			mbox_send_message(glink->mbox_chan, NULL);
1023 			mbox_client_txdone(glink->mbox_chan, 0);
1024 			break;
1025 		case RPM_CMD_INTENT:
1026 			qcom_glink_handle_intent(glink, param1, param2, avail);
1027 			break;
1028 		case RPM_CMD_RX_DONE:
1029 			qcom_glink_handle_rx_done(glink, param1, param2, false);
1030 			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
1031 			break;
1032 		case RPM_CMD_RX_DONE_W_REUSE:
1033 			qcom_glink_handle_rx_done(glink, param1, param2, true);
1034 			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
1035 			break;
1036 		case RPM_CMD_RX_INTENT_REQ_ACK:
1037 			qcom_glink_handle_intent_req_ack(glink, param1, param2);
1038 			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
1039 			break;
1040 		default:
1041 			dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
1042 			ret = -EINVAL;
1043 			break;
1044 		}
1045 
1046 		if (ret)
1047 			break;
1048 	}
1049 
1050 	return IRQ_HANDLED;
1051 }
1052 
1053 /* Locally initiated rpmsg_create_ept */
1054 static struct glink_channel *qcom_glink_create_local(struct qcom_glink *glink,
1055 						     const char *name)
1056 {
1057 	struct glink_channel *channel;
1058 	int ret;
1059 	unsigned long flags;
1060 
1061 	channel = qcom_glink_alloc_channel(glink, name);
1062 	if (IS_ERR(channel))
1063 		return ERR_CAST(channel);
1064 
1065 	ret = qcom_glink_send_open_req(glink, channel);
1066 	if (ret)
1067 		goto release_channel;
1068 
1069 	ret = wait_for_completion_timeout(&channel->open_ack, 5 * HZ);
1070 	if (!ret)
1071 		goto err_timeout;
1072 
1073 	ret = wait_for_completion_timeout(&channel->open_req, 5 * HZ);
1074 	if (!ret)
1075 		goto err_timeout;
1076 
1077 	qcom_glink_send_open_ack(glink, channel);
1078 
1079 	return channel;
1080 
1081 err_timeout:
1082 	/* qcom_glink_send_open_req() did register the channel in lcids*/
1083 	spin_lock_irqsave(&glink->idr_lock, flags);
1084 	idr_remove(&glink->lcids, channel->lcid);
1085 	spin_unlock_irqrestore(&glink->idr_lock, flags);
1086 
1087 release_channel:
1088 	/* Release qcom_glink_send_open_req() reference */
1089 	kref_put(&channel->refcount, qcom_glink_channel_release);
1090 	/* Release qcom_glink_alloc_channel() reference */
1091 	kref_put(&channel->refcount, qcom_glink_channel_release);
1092 
1093 	return ERR_PTR(-ETIMEDOUT);
1094 }
1095 
1096 /* Remote initiated rpmsg_create_ept */
1097 static int qcom_glink_create_remote(struct qcom_glink *glink,
1098 				    struct glink_channel *channel)
1099 {
1100 	int ret;
1101 
1102 	qcom_glink_send_open_ack(glink, channel);
1103 
1104 	ret = qcom_glink_send_open_req(glink, channel);
1105 	if (ret)
1106 		goto close_link;
1107 
1108 	ret = wait_for_completion_timeout(&channel->open_ack, 5 * HZ);
1109 	if (!ret) {
1110 		ret = -ETIMEDOUT;
1111 		goto close_link;
1112 	}
1113 
1114 	return 0;
1115 
1116 close_link:
1117 	/*
1118 	 * Send a close request to "undo" our open-ack. The close-ack will
1119 	 * release qcom_glink_send_open_req() reference and the last reference
1120 	 * will be relesed after receiving remote_close or transport unregister
1121 	 * by calling qcom_glink_native_remove().
1122 	 */
1123 	qcom_glink_send_close_req(glink, channel);
1124 
1125 	return ret;
1126 }
1127 
1128 static struct rpmsg_endpoint *qcom_glink_create_ept(struct rpmsg_device *rpdev,
1129 						    rpmsg_rx_cb_t cb,
1130 						    void *priv,
1131 						    struct rpmsg_channel_info
1132 									chinfo)
1133 {
1134 	struct glink_channel *parent = to_glink_channel(rpdev->ept);
1135 	struct glink_channel *channel;
1136 	struct qcom_glink *glink = parent->glink;
1137 	struct rpmsg_endpoint *ept;
1138 	const char *name = chinfo.name;
1139 	int cid;
1140 	int ret;
1141 	unsigned long flags;
1142 
1143 	spin_lock_irqsave(&glink->idr_lock, flags);
1144 	idr_for_each_entry(&glink->rcids, channel, cid) {
1145 		if (!strcmp(channel->name, name))
1146 			break;
1147 	}
1148 	spin_unlock_irqrestore(&glink->idr_lock, flags);
1149 
1150 	if (!channel) {
1151 		channel = qcom_glink_create_local(glink, name);
1152 		if (IS_ERR(channel))
1153 			return NULL;
1154 	} else {
1155 		ret = qcom_glink_create_remote(glink, channel);
1156 		if (ret)
1157 			return NULL;
1158 	}
1159 
1160 	ept = &channel->ept;
1161 	ept->rpdev = rpdev;
1162 	ept->cb = cb;
1163 	ept->priv = priv;
1164 	ept->ops = &glink_endpoint_ops;
1165 
1166 	return ept;
1167 }
1168 
1169 static int qcom_glink_announce_create(struct rpmsg_device *rpdev)
1170 {
1171 	struct glink_channel *channel = to_glink_channel(rpdev->ept);
1172 	struct device_node *np = rpdev->dev.of_node;
1173 	struct qcom_glink *glink = channel->glink;
1174 	struct glink_core_rx_intent *intent;
1175 	const struct property *prop = NULL;
1176 	__be32 defaults[] = { cpu_to_be32(SZ_1K), cpu_to_be32(5) };
1177 	int num_intents;
1178 	int num_groups = 1;
1179 	__be32 *val = defaults;
1180 	int size;
1181 
1182 	if (glink->intentless || !completion_done(&channel->open_ack))
1183 		return 0;
1184 
1185 	prop = of_find_property(np, "qcom,intents", NULL);
1186 	if (prop) {
1187 		val = prop->value;
1188 		num_groups = prop->length / sizeof(u32) / 2;
1189 	}
1190 
1191 	/* Channel is now open, advertise base set of intents */
1192 	while (num_groups--) {
1193 		size = be32_to_cpup(val++);
1194 		num_intents = be32_to_cpup(val++);
1195 		while (num_intents--) {
1196 			intent = qcom_glink_alloc_intent(glink, channel, size,
1197 							 true);
1198 			if (!intent)
1199 				break;
1200 
1201 			qcom_glink_advertise_intent(glink, channel, intent);
1202 		}
1203 	}
1204 	return 0;
1205 }
1206 
1207 static void qcom_glink_destroy_ept(struct rpmsg_endpoint *ept)
1208 {
1209 	struct glink_channel *channel = to_glink_channel(ept);
1210 	struct qcom_glink *glink = channel->glink;
1211 	unsigned long flags;
1212 
1213 	spin_lock_irqsave(&channel->recv_lock, flags);
1214 	channel->ept.cb = NULL;
1215 	spin_unlock_irqrestore(&channel->recv_lock, flags);
1216 
1217 	/* Decouple the potential rpdev from the channel */
1218 	channel->rpdev = NULL;
1219 
1220 	qcom_glink_send_close_req(glink, channel);
1221 }
1222 
1223 static int qcom_glink_request_intent(struct qcom_glink *glink,
1224 				     struct glink_channel *channel,
1225 				     size_t size)
1226 {
1227 	struct {
1228 		u16 id;
1229 		u16 cid;
1230 		u32 size;
1231 	} __packed cmd;
1232 
1233 	int ret;
1234 
1235 	mutex_lock(&channel->intent_req_lock);
1236 
1237 	reinit_completion(&channel->intent_req_comp);
1238 
1239 	cmd.id = RPM_CMD_RX_INTENT_REQ;
1240 	cmd.cid = channel->lcid;
1241 	cmd.size = size;
1242 
1243 	ret = qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
1244 	if (ret)
1245 		goto unlock;
1246 
1247 	ret = wait_for_completion_timeout(&channel->intent_req_comp, 10 * HZ);
1248 	if (!ret) {
1249 		dev_err(glink->dev, "intent request timed out\n");
1250 		ret = -ETIMEDOUT;
1251 	} else {
1252 		ret = channel->intent_req_result ? 0 : -ECANCELED;
1253 	}
1254 
1255 unlock:
1256 	mutex_unlock(&channel->intent_req_lock);
1257 	return ret;
1258 }
1259 
1260 static int __qcom_glink_send(struct glink_channel *channel,
1261 			     void *data, int len, bool wait)
1262 {
1263 	struct qcom_glink *glink = channel->glink;
1264 	struct glink_core_rx_intent *intent = NULL;
1265 	struct glink_core_rx_intent *tmp;
1266 	int iid = 0;
1267 	struct {
1268 		struct glink_msg msg;
1269 		__le32 chunk_size;
1270 		__le32 left_size;
1271 	} __packed req;
1272 	int ret;
1273 	unsigned long flags;
1274 
1275 	if (!glink->intentless) {
1276 		while (!intent) {
1277 			spin_lock_irqsave(&channel->intent_lock, flags);
1278 			idr_for_each_entry(&channel->riids, tmp, iid) {
1279 				if (tmp->size >= len && !tmp->in_use) {
1280 					if (!intent)
1281 						intent = tmp;
1282 					else if (intent->size > tmp->size)
1283 						intent = tmp;
1284 					if (intent->size == len)
1285 						break;
1286 				}
1287 			}
1288 			if (intent)
1289 				intent->in_use = true;
1290 			spin_unlock_irqrestore(&channel->intent_lock, flags);
1291 
1292 			/* We found an available intent */
1293 			if (intent)
1294 				break;
1295 
1296 			if (!wait)
1297 				return -EBUSY;
1298 
1299 			ret = qcom_glink_request_intent(glink, channel, len);
1300 			if (ret < 0)
1301 				return ret;
1302 		}
1303 
1304 		iid = intent->id;
1305 	}
1306 
1307 	req.msg.cmd = cpu_to_le16(RPM_CMD_TX_DATA);
1308 	req.msg.param1 = cpu_to_le16(channel->lcid);
1309 	req.msg.param2 = cpu_to_le32(iid);
1310 	req.chunk_size = cpu_to_le32(len);
1311 	req.left_size = cpu_to_le32(0);
1312 
1313 	ret = qcom_glink_tx(glink, &req, sizeof(req), data, len, wait);
1314 
1315 	/* Mark intent available if we failed */
1316 	if (ret && intent)
1317 		intent->in_use = false;
1318 
1319 	return ret;
1320 }
1321 
1322 static int qcom_glink_send(struct rpmsg_endpoint *ept, void *data, int len)
1323 {
1324 	struct glink_channel *channel = to_glink_channel(ept);
1325 
1326 	return __qcom_glink_send(channel, data, len, true);
1327 }
1328 
1329 static int qcom_glink_trysend(struct rpmsg_endpoint *ept, void *data, int len)
1330 {
1331 	struct glink_channel *channel = to_glink_channel(ept);
1332 
1333 	return __qcom_glink_send(channel, data, len, false);
1334 }
1335 
1336 static int qcom_glink_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
1337 {
1338 	struct glink_channel *channel = to_glink_channel(ept);
1339 
1340 	return __qcom_glink_send(channel, data, len, true);
1341 }
1342 
1343 static int qcom_glink_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
1344 {
1345 	struct glink_channel *channel = to_glink_channel(ept);
1346 
1347 	return __qcom_glink_send(channel, data, len, false);
1348 }
1349 
1350 /*
1351  * Finds the device_node for the glink child interested in this channel.
1352  */
1353 static struct device_node *qcom_glink_match_channel(struct device_node *node,
1354 						    const char *channel)
1355 {
1356 	struct device_node *child;
1357 	const char *name;
1358 	const char *key;
1359 	int ret;
1360 
1361 	for_each_available_child_of_node(node, child) {
1362 		key = "qcom,glink-channels";
1363 		ret = of_property_read_string(child, key, &name);
1364 		if (ret)
1365 			continue;
1366 
1367 		if (strcmp(name, channel) == 0)
1368 			return child;
1369 	}
1370 
1371 	return NULL;
1372 }
1373 
1374 static const struct rpmsg_device_ops glink_device_ops = {
1375 	.create_ept = qcom_glink_create_ept,
1376 	.announce_create = qcom_glink_announce_create,
1377 };
1378 
1379 static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
1380 	.destroy_ept = qcom_glink_destroy_ept,
1381 	.send = qcom_glink_send,
1382 	.sendto = qcom_glink_sendto,
1383 	.trysend = qcom_glink_trysend,
1384 	.trysendto = qcom_glink_trysendto,
1385 };
1386 
1387 static void qcom_glink_rpdev_release(struct device *dev)
1388 {
1389 	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
1390 	struct glink_channel *channel = to_glink_channel(rpdev->ept);
1391 
1392 	channel->rpdev = NULL;
1393 	kfree(rpdev);
1394 }
1395 
1396 static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
1397 			      char *name)
1398 {
1399 	struct glink_channel *channel;
1400 	struct rpmsg_device *rpdev;
1401 	bool create_device = false;
1402 	struct device_node *node;
1403 	int lcid;
1404 	int ret;
1405 	unsigned long flags;
1406 
1407 	spin_lock_irqsave(&glink->idr_lock, flags);
1408 	idr_for_each_entry(&glink->lcids, channel, lcid) {
1409 		if (!strcmp(channel->name, name))
1410 			break;
1411 	}
1412 	spin_unlock_irqrestore(&glink->idr_lock, flags);
1413 
1414 	if (!channel) {
1415 		channel = qcom_glink_alloc_channel(glink, name);
1416 		if (IS_ERR(channel))
1417 			return PTR_ERR(channel);
1418 
1419 		/* The opening dance was initiated by the remote */
1420 		create_device = true;
1421 	}
1422 
1423 	spin_lock_irqsave(&glink->idr_lock, flags);
1424 	ret = idr_alloc(&glink->rcids, channel, rcid, rcid + 1, GFP_ATOMIC);
1425 	if (ret < 0) {
1426 		dev_err(glink->dev, "Unable to insert channel into rcid list\n");
1427 		spin_unlock_irqrestore(&glink->idr_lock, flags);
1428 		goto free_channel;
1429 	}
1430 	channel->rcid = ret;
1431 	spin_unlock_irqrestore(&glink->idr_lock, flags);
1432 
1433 	complete_all(&channel->open_req);
1434 
1435 	if (create_device) {
1436 		rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
1437 		if (!rpdev) {
1438 			ret = -ENOMEM;
1439 			goto rcid_remove;
1440 		}
1441 
1442 		rpdev->ept = &channel->ept;
1443 		strncpy(rpdev->id.name, name, RPMSG_NAME_SIZE);
1444 		rpdev->src = RPMSG_ADDR_ANY;
1445 		rpdev->dst = RPMSG_ADDR_ANY;
1446 		rpdev->ops = &glink_device_ops;
1447 
1448 		node = qcom_glink_match_channel(glink->dev->of_node, name);
1449 		rpdev->dev.of_node = node;
1450 		rpdev->dev.parent = glink->dev;
1451 		rpdev->dev.release = qcom_glink_rpdev_release;
1452 
1453 		ret = rpmsg_register_device(rpdev);
1454 		if (ret)
1455 			goto rcid_remove;
1456 
1457 		channel->rpdev = rpdev;
1458 	}
1459 
1460 	return 0;
1461 
1462 rcid_remove:
1463 	spin_lock_irqsave(&glink->idr_lock, flags);
1464 	idr_remove(&glink->rcids, channel->rcid);
1465 	channel->rcid = 0;
1466 	spin_unlock_irqrestore(&glink->idr_lock, flags);
1467 free_channel:
1468 	/* Release the reference, iff we took it */
1469 	if (create_device)
1470 		kref_put(&channel->refcount, qcom_glink_channel_release);
1471 
1472 	return ret;
1473 }
1474 
1475 static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
1476 {
1477 	struct rpmsg_channel_info chinfo;
1478 	struct glink_channel *channel;
1479 	unsigned long flags;
1480 
1481 	spin_lock_irqsave(&glink->idr_lock, flags);
1482 	channel = idr_find(&glink->rcids, rcid);
1483 	spin_unlock_irqrestore(&glink->idr_lock, flags);
1484 	if (WARN(!channel, "close request on unknown channel\n"))
1485 		return;
1486 
1487 	/* cancel pending rx_done work */
1488 	cancel_work_sync(&channel->intent_work);
1489 
1490 	if (channel->rpdev) {
1491 		strncpy(chinfo.name, channel->name, sizeof(chinfo.name));
1492 		chinfo.src = RPMSG_ADDR_ANY;
1493 		chinfo.dst = RPMSG_ADDR_ANY;
1494 
1495 		rpmsg_unregister_device(glink->dev, &chinfo);
1496 	}
1497 
1498 	qcom_glink_send_close_ack(glink, channel->rcid);
1499 
1500 	spin_lock_irqsave(&glink->idr_lock, flags);
1501 	idr_remove(&glink->rcids, channel->rcid);
1502 	channel->rcid = 0;
1503 	spin_unlock_irqrestore(&glink->idr_lock, flags);
1504 
1505 	kref_put(&channel->refcount, qcom_glink_channel_release);
1506 }
1507 
1508 static void qcom_glink_rx_close_ack(struct qcom_glink *glink, unsigned int lcid)
1509 {
1510 	struct glink_channel *channel;
1511 	unsigned long flags;
1512 
1513 	spin_lock_irqsave(&glink->idr_lock, flags);
1514 	channel = idr_find(&glink->lcids, lcid);
1515 	if (WARN(!channel, "close ack on unknown channel\n")) {
1516 		spin_unlock_irqrestore(&glink->idr_lock, flags);
1517 		return;
1518 	}
1519 
1520 	idr_remove(&glink->lcids, channel->lcid);
1521 	channel->lcid = 0;
1522 	spin_unlock_irqrestore(&glink->idr_lock, flags);
1523 
1524 	kref_put(&channel->refcount, qcom_glink_channel_release);
1525 }
1526 
1527 static void qcom_glink_work(struct work_struct *work)
1528 {
1529 	struct qcom_glink *glink = container_of(work, struct qcom_glink,
1530 						rx_work);
1531 	struct glink_defer_cmd *dcmd;
1532 	struct glink_msg *msg;
1533 	unsigned long flags;
1534 	unsigned int param1;
1535 	unsigned int param2;
1536 	unsigned int cmd;
1537 
1538 	for (;;) {
1539 		spin_lock_irqsave(&glink->rx_lock, flags);
1540 		if (list_empty(&glink->rx_queue)) {
1541 			spin_unlock_irqrestore(&glink->rx_lock, flags);
1542 			break;
1543 		}
1544 		dcmd = list_first_entry(&glink->rx_queue,
1545 					struct glink_defer_cmd, node);
1546 		list_del(&dcmd->node);
1547 		spin_unlock_irqrestore(&glink->rx_lock, flags);
1548 
1549 		msg = &dcmd->msg;
1550 		cmd = le16_to_cpu(msg->cmd);
1551 		param1 = le16_to_cpu(msg->param1);
1552 		param2 = le32_to_cpu(msg->param2);
1553 
1554 		switch (cmd) {
1555 		case RPM_CMD_VERSION:
1556 			qcom_glink_receive_version(glink, param1, param2);
1557 			break;
1558 		case RPM_CMD_VERSION_ACK:
1559 			qcom_glink_receive_version_ack(glink, param1, param2);
1560 			break;
1561 		case RPM_CMD_OPEN:
1562 			qcom_glink_rx_open(glink, param1, msg->data);
1563 			break;
1564 		case RPM_CMD_CLOSE:
1565 			qcom_glink_rx_close(glink, param1);
1566 			break;
1567 		case RPM_CMD_CLOSE_ACK:
1568 			qcom_glink_rx_close_ack(glink, param1);
1569 			break;
1570 		case RPM_CMD_RX_INTENT_REQ:
1571 			qcom_glink_handle_intent_req(glink, param1, param2);
1572 			break;
1573 		default:
1574 			WARN(1, "Unknown defer object %d\n", cmd);
1575 			break;
1576 		}
1577 
1578 		kfree(dcmd);
1579 	}
1580 }
1581 
1582 static void qcom_glink_cancel_rx_work(struct qcom_glink *glink)
1583 {
1584 	struct glink_defer_cmd *dcmd;
1585 	struct glink_defer_cmd *tmp;
1586 
1587 	/* cancel any pending deferred rx_work */
1588 	cancel_work_sync(&glink->rx_work);
1589 
1590 	list_for_each_entry_safe(dcmd, tmp, &glink->rx_queue, node)
1591 		kfree(dcmd);
1592 }
1593 
1594 static ssize_t rpmsg_name_show(struct device *dev,
1595 			       struct device_attribute *attr, char *buf)
1596 {
1597 	int ret = 0;
1598 	const char *name;
1599 
1600 	ret = of_property_read_string(dev->of_node, "label", &name);
1601 	if (ret < 0)
1602 		name = dev->of_node->name;
1603 
1604 	return snprintf(buf, RPMSG_NAME_SIZE, "%s\n", name);
1605 }
1606 static DEVICE_ATTR_RO(rpmsg_name);
1607 
1608 static struct attribute *qcom_glink_attrs[] = {
1609 	&dev_attr_rpmsg_name.attr,
1610 	NULL
1611 };
1612 ATTRIBUTE_GROUPS(qcom_glink);
1613 
1614 static void qcom_glink_device_release(struct device *dev)
1615 {
1616 	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
1617 	struct glink_channel *channel = to_glink_channel(rpdev->ept);
1618 
1619 	/* Release qcom_glink_alloc_channel() reference */
1620 	kref_put(&channel->refcount, qcom_glink_channel_release);
1621 	kfree(rpdev);
1622 }
1623 
1624 static int qcom_glink_create_chrdev(struct qcom_glink *glink)
1625 {
1626 	struct rpmsg_device *rpdev;
1627 	struct glink_channel *channel;
1628 
1629 	rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
1630 	if (!rpdev)
1631 		return -ENOMEM;
1632 
1633 	channel = qcom_glink_alloc_channel(glink, "rpmsg_chrdev");
1634 	if (IS_ERR(channel)) {
1635 		kfree(rpdev);
1636 		return PTR_ERR(channel);
1637 	}
1638 	channel->rpdev = rpdev;
1639 
1640 	rpdev->ept = &channel->ept;
1641 	rpdev->ops = &glink_device_ops;
1642 	rpdev->dev.parent = glink->dev;
1643 	rpdev->dev.release = qcom_glink_device_release;
1644 
1645 	return rpmsg_chrdev_register_device(rpdev);
1646 }
1647 
1648 struct qcom_glink *qcom_glink_native_probe(struct device *dev,
1649 					   unsigned long features,
1650 					   struct qcom_glink_pipe *rx,
1651 					   struct qcom_glink_pipe *tx,
1652 					   bool intentless)
1653 {
1654 	int irq;
1655 	int ret;
1656 	struct qcom_glink *glink;
1657 
1658 	glink = devm_kzalloc(dev, sizeof(*glink), GFP_KERNEL);
1659 	if (!glink)
1660 		return ERR_PTR(-ENOMEM);
1661 
1662 	glink->dev = dev;
1663 	glink->tx_pipe = tx;
1664 	glink->rx_pipe = rx;
1665 
1666 	glink->features = features;
1667 	glink->intentless = intentless;
1668 
1669 	spin_lock_init(&glink->tx_lock);
1670 	spin_lock_init(&glink->rx_lock);
1671 	INIT_LIST_HEAD(&glink->rx_queue);
1672 	INIT_WORK(&glink->rx_work, qcom_glink_work);
1673 
1674 	spin_lock_init(&glink->idr_lock);
1675 	idr_init(&glink->lcids);
1676 	idr_init(&glink->rcids);
1677 
1678 	glink->dev->groups = qcom_glink_groups;
1679 
1680 	ret = device_add_groups(dev, qcom_glink_groups);
1681 	if (ret)
1682 		dev_err(dev, "failed to add groups\n");
1683 
1684 	ret = of_property_read_string(dev->of_node, "label", &glink->name);
1685 	if (ret < 0)
1686 		glink->name = dev->of_node->name;
1687 
1688 	glink->mbox_client.dev = dev;
1689 	glink->mbox_client.knows_txdone = true;
1690 	glink->mbox_chan = mbox_request_channel(&glink->mbox_client, 0);
1691 	if (IS_ERR(glink->mbox_chan)) {
1692 		if (PTR_ERR(glink->mbox_chan) != -EPROBE_DEFER)
1693 			dev_err(dev, "failed to acquire IPC channel\n");
1694 		return ERR_CAST(glink->mbox_chan);
1695 	}
1696 
1697 	irq = of_irq_get(dev->of_node, 0);
1698 	ret = devm_request_irq(dev, irq,
1699 			       qcom_glink_native_intr,
1700 			       IRQF_NO_SUSPEND | IRQF_SHARED,
1701 			       "glink-native", glink);
1702 	if (ret) {
1703 		dev_err(dev, "failed to request IRQ\n");
1704 		return ERR_PTR(ret);
1705 	}
1706 
1707 	glink->irq = irq;
1708 
1709 	ret = qcom_glink_send_version(glink);
1710 	if (ret)
1711 		return ERR_PTR(ret);
1712 
1713 	ret = qcom_glink_create_chrdev(glink);
1714 	if (ret)
1715 		dev_err(glink->dev, "failed to register chrdev\n");
1716 
1717 	return glink;
1718 }
1719 EXPORT_SYMBOL_GPL(qcom_glink_native_probe);
1720 
1721 static int qcom_glink_remove_device(struct device *dev, void *data)
1722 {
1723 	device_unregister(dev);
1724 
1725 	return 0;
1726 }
1727 
1728 void qcom_glink_native_remove(struct qcom_glink *glink)
1729 {
1730 	struct glink_channel *channel;
1731 	int cid;
1732 	int ret;
1733 
1734 	disable_irq(glink->irq);
1735 	qcom_glink_cancel_rx_work(glink);
1736 
1737 	ret = device_for_each_child(glink->dev, NULL, qcom_glink_remove_device);
1738 	if (ret)
1739 		dev_warn(glink->dev, "Can't remove GLINK devices: %d\n", ret);
1740 
1741 	/* Release any defunct local channels, waiting for close-ack */
1742 	idr_for_each_entry(&glink->lcids, channel, cid)
1743 		kref_put(&channel->refcount, qcom_glink_channel_release);
1744 
1745 	/* Release any defunct local channels, waiting for close-req */
1746 	idr_for_each_entry(&glink->rcids, channel, cid)
1747 		kref_put(&channel->refcount, qcom_glink_channel_release);
1748 
1749 	idr_destroy(&glink->lcids);
1750 	idr_destroy(&glink->rcids);
1751 	mbox_free_channel(glink->mbox_chan);
1752 }
1753 EXPORT_SYMBOL_GPL(qcom_glink_native_remove);
1754 
1755 void qcom_glink_native_unregister(struct qcom_glink *glink)
1756 {
1757 	device_unregister(glink->dev);
1758 }
1759 EXPORT_SYMBOL_GPL(qcom_glink_native_unregister);
1760 
1761 MODULE_DESCRIPTION("Qualcomm GLINK driver");
1762 MODULE_LICENSE("GPL v2");
1763