summaryrefslogtreecommitdiff
path: root/drivers/net/wwan/mhi_wwan_mbim.c
blob: 6872782e8dd89a362b5ebf24b644bc0f935ce03b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
// SPDX-License-Identifier: GPL-2.0-or-later
/* MHI MBIM Network driver - Network/MBIM over MHI bus
 *
 * Copyright (C) 2021 Linaro Ltd <loic.poulain@linaro.org>
 *
 * This driver copy some code from cdc_ncm, which is:
 * Copyright (C) ST-Ericsson 2010-2012
 * and cdc_mbim, which is:
 * Copyright (c) 2012  Smith Micro Software, Inc.
 * Copyright (c) 2012  Bjørn Mork <bjorn@mork.no>
 *
 */

#include <linux/ethtool.h>
#include <linux/if_arp.h>
#include <linux/if_vlan.h>
#include <linux/ip.h>
#include <linux/mhi.h>
#include <linux/mii.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/u64_stats_sync.h>
#include <linux/usb.h>
#include <linux/usb/cdc.h>
#include <linux/usb/usbnet.h>
#include <linux/usb/cdc_ncm.h>
#include <linux/wwan.h>

/* 3500 allows to optimize skb allocation, the skbs will basically fit in
 * one 4K page. Large MBIM packets will simply be split over several MHI
 * transfers and chained by the MHI net layer (zerocopy).
 */
#define MHI_DEFAULT_MRU 3500

#define MHI_MBIM_DEFAULT_MTU 1500
#define MHI_MAX_BUF_SZ 0xffff

#define MBIM_NDP16_SIGN_MASK 0x00ffffff

#define MHI_MBIM_LINK_HASH_SIZE 8
#define LINK_HASH(session) ((session) % MHI_MBIM_LINK_HASH_SIZE)

struct mhi_mbim_link {
	struct mhi_mbim_context *mbim;
	struct net_device *ndev;
	unsigned int session;

	/* stats */
	u64_stats_t rx_packets;
	u64_stats_t rx_bytes;
	u64_stats_t rx_errors;
	u64_stats_t tx_packets;
	u64_stats_t tx_bytes;
	u64_stats_t tx_errors;
	u64_stats_t tx_dropped;
	struct u64_stats_sync tx_syncp;
	struct u64_stats_sync rx_syncp;

	struct hlist_node hlnode;
};

struct mhi_mbim_context {
	struct mhi_device *mdev;
	struct sk_buff *skbagg_head;
	struct sk_buff *skbagg_tail;
	unsigned int mru;
	u32 rx_queue_sz;
	u16 rx_seq;
	u16 tx_seq;
	struct delayed_work rx_refill;
	spinlock_t tx_lock;
	struct hlist_head link_list[MHI_MBIM_LINK_HASH_SIZE];
};

struct mbim_tx_hdr {
	struct usb_cdc_ncm_nth16 nth16;
	struct usb_cdc_ncm_ndp16 ndp16;
	struct usb_cdc_ncm_dpe16 dpe16[2];
} __packed;

static struct mhi_mbim_link *mhi_mbim_get_link_rcu(struct mhi_mbim_context *mbim,
						   unsigned int session)
{
	struct mhi_mbim_link *link;

	hlist_for_each_entry_rcu(link, &mbim->link_list[LINK_HASH(session)], hlnode) {
		if (link->session == session)
			return link;
	}

	return NULL;
}

static struct sk_buff *mbim_tx_fixup(struct sk_buff *skb, unsigned int session,
				     u16 tx_seq)
{
	unsigned int dgram_size = skb->len;
	struct usb_cdc_ncm_nth16 *nth16;
	struct usb_cdc_ncm_ndp16 *ndp16;
	struct mbim_tx_hdr *mbim_hdr;

	/* Only one NDP is sent, containing the IP packet (no aggregation) */

	/* Ensure we have enough headroom for crafting MBIM header */
	if (skb_cow_head(skb, sizeof(struct mbim_tx_hdr))) {
		dev_kfree_skb_any(skb);
		return NULL;
	}

	mbim_hdr = skb_push(skb, sizeof(struct mbim_tx_hdr));

	/* Fill NTB header */
	nth16 = &mbim_hdr->nth16;
	nth16->dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN);
	nth16->wHeaderLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16));
	nth16->wSequence = cpu_to_le16(tx_seq);
	nth16->wBlockLength = cpu_to_le16(skb->len);
	nth16->wNdpIndex = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16));

	/* Fill the unique NDP */
	ndp16 = &mbim_hdr->ndp16;
	ndp16->dwSignature = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN | (session << 24));
	ndp16->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp16)
					+ sizeof(struct usb_cdc_ncm_dpe16) * 2);
	ndp16->wNextNdpIndex = 0;

	/* Datagram follows the mbim header */
	ndp16->dpe16[0].wDatagramIndex = cpu_to_le16(sizeof(struct mbim_tx_hdr));
	ndp16->dpe16[0].wDatagramLength = cpu_to_le16(dgram_size);

	/* null termination */
	ndp16->dpe16[1].wDatagramIndex = 0;
	ndp16->dpe16[1].wDatagramLength = 0;

	return skb;
}

static netdev_tx_t mhi_mbim_ndo_xmit(struct sk_buff *skb, struct net_device *ndev)
{
	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
	struct mhi_mbim_context *mbim = link->mbim;
	unsigned long flags;
	int err = -ENOMEM;

	/* Serialize MHI channel queuing and MBIM seq */
	spin_lock_irqsave(&mbim->tx_lock, flags);

	skb = mbim_tx_fixup(skb, link->session, mbim->tx_seq);
	if (unlikely(!skb))
		goto exit_unlock;

	err = mhi_queue_skb(mbim->mdev, DMA_TO_DEVICE, skb, skb->len, MHI_EOT);

	if (mhi_queue_is_full(mbim->mdev, DMA_TO_DEVICE))
		netif_stop_queue(ndev);

	if (!err)
		mbim->tx_seq++;

exit_unlock:
	spin_unlock_irqrestore(&mbim->tx_lock, flags);

	if (unlikely(err)) {
		net_err_ratelimited("%s: Failed to queue TX buf (%d)\n",
				    ndev->name, err);
		dev_kfree_skb_any(skb);
		goto exit_drop;
	}

	return NETDEV_TX_OK;

exit_drop:
	u64_stats_update_begin(&link->tx_syncp);
	u64_stats_inc(&link->tx_dropped);
	u64_stats_update_end(&link->tx_syncp);

	return NETDEV_TX_OK;
}

static int mbim_rx_verify_nth16(struct mhi_mbim_context *mbim, struct sk_buff *skb)
{
	struct usb_cdc_ncm_nth16 *nth16;
	int len;

	if (skb->len < sizeof(struct usb_cdc_ncm_nth16) +
			sizeof(struct usb_cdc_ncm_ndp16)) {
		net_err_ratelimited("frame too short\n");
		return -EINVAL;
	}

	nth16 = (struct usb_cdc_ncm_nth16 *)skb->data;

	if (nth16->dwSignature != cpu_to_le32(USB_CDC_NCM_NTH16_SIGN)) {
		net_err_ratelimited("invalid NTH16 signature <%#010x>\n",
				    le32_to_cpu(nth16->dwSignature));
		return -EINVAL;
	}

	/* No limit on the block length, except the size of the data pkt */
	len = le16_to_cpu(nth16->wBlockLength);
	if (len > skb->len) {
		net_err_ratelimited("NTB does not fit into the skb %u/%u\n",
				    len, skb->len);
		return -EINVAL;
	}

	if (mbim->rx_seq + 1 != le16_to_cpu(nth16->wSequence) &&
	    (mbim->rx_seq || le16_to_cpu(nth16->wSequence)) &&
	    !(mbim->rx_seq == 0xffff && !le16_to_cpu(nth16->wSequence))) {
		net_err_ratelimited("sequence number glitch prev=%d curr=%d\n",
				    mbim->rx_seq, le16_to_cpu(nth16->wSequence));
	}
	mbim->rx_seq = le16_to_cpu(nth16->wSequence);

	return le16_to_cpu(nth16->wNdpIndex);
}

static int mbim_rx_verify_ndp16(struct sk_buff *skb, struct usb_cdc_ncm_ndp16 *ndp16)
{
	int ret;

	if (le16_to_cpu(ndp16->wLength) < USB_CDC_NCM_NDP16_LENGTH_MIN) {
		net_err_ratelimited("invalid DPT16 length <%u>\n",
				    le16_to_cpu(ndp16->wLength));
		return -EINVAL;
	}

	ret = ((le16_to_cpu(ndp16->wLength) - sizeof(struct usb_cdc_ncm_ndp16))
			/ sizeof(struct usb_cdc_ncm_dpe16));
	ret--; /* Last entry is always a NULL terminator */

	if (sizeof(struct usb_cdc_ncm_ndp16) +
	     ret * sizeof(struct usb_cdc_ncm_dpe16) > skb->len) {
		net_err_ratelimited("Invalid nframes = %d\n", ret);
		return -EINVAL;
	}

	return ret;
}

static void mhi_mbim_rx(struct mhi_mbim_context *mbim, struct sk_buff *skb)
{
	int ndpoffset;

	/* Check NTB header and retrieve first NDP offset */
	ndpoffset = mbim_rx_verify_nth16(mbim, skb);
	if (ndpoffset < 0) {
		net_err_ratelimited("mbim: Incorrect NTB header\n");
		goto error;
	}

	/* Process each NDP */
	while (1) {
		struct usb_cdc_ncm_ndp16 ndp16;
		struct usb_cdc_ncm_dpe16 dpe16;
		struct mhi_mbim_link *link;
		int nframes, n, dpeoffset;
		unsigned int session;

		if (skb_copy_bits(skb, ndpoffset, &ndp16, sizeof(ndp16))) {
			net_err_ratelimited("mbim: Incorrect NDP offset (%u)\n",
					    ndpoffset);
			goto error;
		}

		/* Check NDP header and retrieve number of datagrams */
		nframes = mbim_rx_verify_ndp16(skb, &ndp16);
		if (nframes < 0) {
			net_err_ratelimited("mbim: Incorrect NDP16\n");
			goto error;
		}

		 /* Only IP data type supported, no DSS in MHI context */
		if ((ndp16.dwSignature & cpu_to_le32(MBIM_NDP16_SIGN_MASK))
				!= cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN)) {
			net_err_ratelimited("mbim: Unsupported NDP type\n");
			goto next_ndp;
		}

		session = (le32_to_cpu(ndp16.dwSignature) & ~MBIM_NDP16_SIGN_MASK) >> 24;

		rcu_read_lock();

		link = mhi_mbim_get_link_rcu(mbim, session);
		if (!link) {
			net_err_ratelimited("mbim: bad packet session (%u)\n", session);
			goto unlock;
		}

		/* de-aggregate and deliver IP packets */
		dpeoffset = ndpoffset + sizeof(struct usb_cdc_ncm_ndp16);
		for (n = 0; n < nframes; n++, dpeoffset += sizeof(dpe16)) {
			u16 dgram_offset, dgram_len;
			struct sk_buff *skbn;

			if (skb_copy_bits(skb, dpeoffset, &dpe16, sizeof(dpe16)))
				break;

			dgram_offset = le16_to_cpu(dpe16.wDatagramIndex);
			dgram_len = le16_to_cpu(dpe16.wDatagramLength);

			if (!dgram_offset || !dgram_len)
				break; /* null terminator */

			skbn = netdev_alloc_skb(link->ndev, dgram_len);
			if (!skbn)
				continue;

			skb_put(skbn, dgram_len);
			skb_copy_bits(skb, dgram_offset, skbn->data, dgram_len);

			switch (skbn->data[0] & 0xf0) {
			case 0x40:
				skbn->protocol = htons(ETH_P_IP);
				break;
			case 0x60:
				skbn->protocol = htons(ETH_P_IPV6);
				break;
			default:
				net_err_ratelimited("%s: unknown protocol\n",
						    link->ndev->name);
				dev_kfree_skb_any(skbn);
				u64_stats_update_begin(&link->rx_syncp);
				u64_stats_inc(&link->rx_errors);
				u64_stats_update_end(&link->rx_syncp);
				continue;
			}

			u64_stats_update_begin(&link->rx_syncp);
			u64_stats_inc(&link->rx_packets);
			u64_stats_add(&link->rx_bytes, skbn->len);
			u64_stats_update_end(&link->rx_syncp);

			netif_rx(skbn);
		}
unlock:
		rcu_read_unlock();
next_ndp:
		/* Other NDP to process? */
		ndpoffset = (int)le16_to_cpu(ndp16.wNextNdpIndex);
		if (!ndpoffset)
			break;
	}

	/* free skb */
	dev_consume_skb_any(skb);
	return;
error:
	dev_kfree_skb_any(skb);
}

static struct sk_buff *mhi_net_skb_agg(struct mhi_mbim_context *mbim,
				       struct sk_buff *skb)
{
	struct sk_buff *head = mbim->skbagg_head;
	struct sk_buff *tail = mbim->skbagg_tail;

	/* This is non-paged skb chaining using frag_list */
	if (!head) {
		mbim->skbagg_head = skb;
		return skb;
	}

	if (!skb_shinfo(head)->frag_list)
		skb_shinfo(head)->frag_list = skb;
	else
		tail->next = skb;

	head->len += skb->len;
	head->data_len += skb->len;
	head->truesize += skb->truesize;

	mbim->skbagg_tail = skb;

	return mbim->skbagg_head;
}

static void mhi_net_rx_refill_work(struct work_struct *work)
{
	struct mhi_mbim_context *mbim = container_of(work, struct mhi_mbim_context,
						     rx_refill.work);
	struct mhi_device *mdev = mbim->mdev;
	int err;

	while (!mhi_queue_is_full(mdev, DMA_FROM_DEVICE)) {
		struct sk_buff *skb = alloc_skb(mbim->mru, GFP_KERNEL);

		if (unlikely(!skb))
			break;

		err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb,
				    mbim->mru, MHI_EOT);
		if (unlikely(err)) {
			kfree_skb(skb);
			break;
		}

		/* Do not hog the CPU if rx buffers are consumed faster than
		 * queued (unlikely).
		 */
		cond_resched();
	}

	/* If we're still starved of rx buffers, reschedule later */
	if (mhi_get_free_desc_count(mdev, DMA_FROM_DEVICE) == mbim->rx_queue_sz)
		schedule_delayed_work(&mbim->rx_refill, HZ / 2);
}

static void mhi_mbim_dl_callback(struct mhi_device *mhi_dev,
				 struct mhi_result *mhi_res)
{
	struct mhi_mbim_context *mbim = dev_get_drvdata(&mhi_dev->dev);
	struct sk_buff *skb = mhi_res->buf_addr;
	int free_desc_count;

	free_desc_count = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);

	if (unlikely(mhi_res->transaction_status)) {
		switch (mhi_res->transaction_status) {
		case -EOVERFLOW:
			/* Packet has been split over multiple transfers */
			skb_put(skb, mhi_res->bytes_xferd);
			mhi_net_skb_agg(mbim, skb);
			break;
		case -ENOTCONN:
			/* MHI layer stopping/resetting the DL channel */
			dev_kfree_skb_any(skb);
			return;
		default:
			/* Unknown error, simply drop */
			dev_kfree_skb_any(skb);
		}
	} else {
		skb_put(skb, mhi_res->bytes_xferd);

		if (mbim->skbagg_head) {
			/* Aggregate the final fragment */
			skb = mhi_net_skb_agg(mbim, skb);
			mbim->skbagg_head = NULL;
		}

		mhi_mbim_rx(mbim, skb);
	}

	/* Refill if RX buffers queue becomes low */
	if (free_desc_count >= mbim->rx_queue_sz / 2)
		schedule_delayed_work(&mbim->rx_refill, 0);
}

static void mhi_mbim_ndo_get_stats64(struct net_device *ndev,
				     struct rtnl_link_stats64 *stats)
{
	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
	unsigned int start;

	do {
		start = u64_stats_fetch_begin_irq(&link->rx_syncp);
		stats->rx_packets = u64_stats_read(&link->rx_packets);
		stats->rx_bytes = u64_stats_read(&link->rx_bytes);
		stats->rx_errors = u64_stats_read(&link->rx_errors);
	} while (u64_stats_fetch_retry_irq(&link->rx_syncp, start));

	do {
		start = u64_stats_fetch_begin_irq(&link->tx_syncp);
		stats->tx_packets = u64_stats_read(&link->tx_packets);
		stats->tx_bytes = u64_stats_read(&link->tx_bytes);
		stats->tx_errors = u64_stats_read(&link->tx_errors);
		stats->tx_dropped = u64_stats_read(&link->tx_dropped);
	} while (u64_stats_fetch_retry_irq(&link->tx_syncp, start));
}

static void mhi_mbim_ul_callback(struct mhi_device *mhi_dev,
				 struct mhi_result *mhi_res)
{
	struct mhi_mbim_context *mbim = dev_get_drvdata(&mhi_dev->dev);
	struct sk_buff *skb = mhi_res->buf_addr;
	struct net_device *ndev = skb->dev;
	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);

	/* Hardware has consumed the buffer, so free the skb (which is not
	 * freed by the MHI stack) and perform accounting.
	 */
	dev_consume_skb_any(skb);

	u64_stats_update_begin(&link->tx_syncp);
	if (unlikely(mhi_res->transaction_status)) {
		/* MHI layer stopping/resetting the UL channel */
		if (mhi_res->transaction_status == -ENOTCONN) {
			u64_stats_update_end(&link->tx_syncp);
			return;
		}

		u64_stats_inc(&link->tx_errors);
	} else {
		u64_stats_inc(&link->tx_packets);
		u64_stats_add(&link->tx_bytes, mhi_res->bytes_xferd);
	}
	u64_stats_update_end(&link->tx_syncp);

	if (netif_queue_stopped(ndev) && !mhi_queue_is_full(mbim->mdev, DMA_TO_DEVICE))
		netif_wake_queue(ndev);
}

static int mhi_mbim_ndo_open(struct net_device *ndev)
{
	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);

	/* Feed the MHI rx buffer pool */
	schedule_delayed_work(&link->mbim->rx_refill, 0);

	/* Carrier is established via out-of-band channel (e.g. qmi) */
	netif_carrier_on(ndev);

	netif_start_queue(ndev);

	return 0;
}

static int mhi_mbim_ndo_stop(struct net_device *ndev)
{
	netif_stop_queue(ndev);
	netif_carrier_off(ndev);

	return 0;
}

static const struct net_device_ops mhi_mbim_ndo = {
	.ndo_open = mhi_mbim_ndo_open,
	.ndo_stop = mhi_mbim_ndo_stop,
	.ndo_start_xmit = mhi_mbim_ndo_xmit,
	.ndo_get_stats64 = mhi_mbim_ndo_get_stats64,
};

static int mhi_mbim_newlink(void *ctxt, struct net_device *ndev, u32 if_id,
			    struct netlink_ext_ack *extack)
{
	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);
	struct mhi_mbim_context *mbim = ctxt;

	link->session = if_id;
	link->mbim = mbim;
	link->ndev = ndev;
	u64_stats_init(&link->rx_syncp);
	u64_stats_init(&link->tx_syncp);

	rcu_read_lock();
	if (mhi_mbim_get_link_rcu(mbim, if_id)) {
		rcu_read_unlock();
		return -EEXIST;
	}
	rcu_read_unlock();

	/* Already protected by RTNL lock */
	hlist_add_head_rcu(&link->hlnode, &mbim->link_list[LINK_HASH(if_id)]);

	return register_netdevice(ndev);
}

static void mhi_mbim_dellink(void *ctxt, struct net_device *ndev,
			     struct list_head *head)
{
	struct mhi_mbim_link *link = wwan_netdev_drvpriv(ndev);

	hlist_del_init_rcu(&link->hlnode);
	synchronize_rcu();

	unregister_netdevice_queue(ndev, head);
}

static void mhi_mbim_setup(struct net_device *ndev)
{
	ndev->header_ops = NULL;  /* No header */
	ndev->type = ARPHRD_RAWIP;
	ndev->needed_headroom = sizeof(struct mbim_tx_hdr);
	ndev->hard_header_len = 0;
	ndev->addr_len = 0;
	ndev->flags = IFF_POINTOPOINT | IFF_NOARP;
	ndev->netdev_ops = &mhi_mbim_ndo;
	ndev->mtu = MHI_MBIM_DEFAULT_MTU;
	ndev->min_mtu = ETH_MIN_MTU;
	ndev->max_mtu = MHI_MAX_BUF_SZ - ndev->needed_headroom;
	ndev->tx_queue_len = 1000;
}

static const struct wwan_ops mhi_mbim_wwan_ops = {
	.priv_size = sizeof(struct mhi_mbim_link),
	.setup = mhi_mbim_setup,
	.newlink = mhi_mbim_newlink,
	.dellink = mhi_mbim_dellink,
};

static int mhi_mbim_probe(struct mhi_device *mhi_dev, const struct mhi_device_id *id)
{
	struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;
	struct mhi_mbim_context *mbim;
	int err;

	mbim = devm_kzalloc(&mhi_dev->dev, sizeof(*mbim), GFP_KERNEL);
	if (!mbim)
		return -ENOMEM;

	spin_lock_init(&mbim->tx_lock);
	dev_set_drvdata(&mhi_dev->dev, mbim);
	mbim->mdev = mhi_dev;
	mbim->mru = mhi_dev->mhi_cntrl->mru ? mhi_dev->mhi_cntrl->mru : MHI_DEFAULT_MRU;

	INIT_DELAYED_WORK(&mbim->rx_refill, mhi_net_rx_refill_work);

	/* Start MHI channels */
	err = mhi_prepare_for_transfer(mhi_dev);
	if (err)
		return err;

	/* Number of transfer descriptors determines size of the queue */
	mbim->rx_queue_sz = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);

	/* Register wwan link ops with MHI controller representing WWAN instance */
	return wwan_register_ops(&cntrl->mhi_dev->dev, &mhi_mbim_wwan_ops, mbim, 0);
}

static void mhi_mbim_remove(struct mhi_device *mhi_dev)
{
	struct mhi_mbim_context *mbim = dev_get_drvdata(&mhi_dev->dev);
	struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;

	mhi_unprepare_from_transfer(mhi_dev);
	cancel_delayed_work_sync(&mbim->rx_refill);
	wwan_unregister_ops(&cntrl->mhi_dev->dev);
	kfree_skb(mbim->skbagg_head);
	dev_set_drvdata(&mhi_dev->dev, NULL);
}

static const struct mhi_device_id mhi_mbim_id_table[] = {
	/* Hardware accelerated data PATH (to modem IPA), MBIM protocol */
	{ .chan = "IP_HW0_MBIM", .driver_data = 0 },
	{}
};
MODULE_DEVICE_TABLE(mhi, mhi_mbim_id_table);

static struct mhi_driver mhi_mbim_driver = {
	.probe = mhi_mbim_probe,
	.remove = mhi_mbim_remove,
	.dl_xfer_cb = mhi_mbim_dl_callback,
	.ul_xfer_cb = mhi_mbim_ul_callback,
	.id_table = mhi_mbim_id_table,
	.driver = {
		.name = "mhi_wwan_mbim",
		.owner = THIS_MODULE,
	},
};

module_mhi_driver(mhi_mbim_driver);

MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
MODULE_DESCRIPTION("Network/MBIM over MHI");
MODULE_LICENSE("GPL v2");