summaryrefslogtreecommitdiffstats
path: root/drivers/net/caif/caif_shmcore.c
blob: bce8bac311c99d0d1d9a2f3a07dc6c0a71fee836 (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
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
/*
 * Copyright (C) ST-Ericsson AB 2010
 * Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
 * Authors:  Amarnath Revanna / amarnath.bangalore.revanna@stericsson.com,
 *           Daniel Martensson / daniel.martensson@stericsson.com
 * License terms: GNU General Public License (GPL) version 2
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":" fmt

#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/io.h>

#include <net/caif/caif_device.h>
#include <net/caif/caif_shm.h>

#define NR_TX_BUF		6
#define NR_RX_BUF		6
#define TX_BUF_SZ		0x2000
#define RX_BUF_SZ		0x2000

#define CAIF_NEEDED_HEADROOM	32

#define CAIF_FLOW_ON		1
#define CAIF_FLOW_OFF		0

#define LOW_WATERMARK		3
#define HIGH_WATERMARK		4

/* Maximum number of CAIF buffers per shared memory buffer. */
#define SHM_MAX_FRMS_PER_BUF	10

/*
 * Size in bytes of the descriptor area
 * (With end of descriptor signalling)
 */
#define SHM_CAIF_DESC_SIZE	((SHM_MAX_FRMS_PER_BUF + 1) * \
					sizeof(struct shm_pck_desc))

/*
 * Offset to the first CAIF frame within a shared memory buffer.
 * Aligned on 32 bytes.
 */
#define SHM_CAIF_FRM_OFS	(SHM_CAIF_DESC_SIZE + (SHM_CAIF_DESC_SIZE % 32))

/* Number of bytes for CAIF shared memory header. */
#define SHM_HDR_LEN		1

/* Number of padding bytes for the complete CAIF frame. */
#define SHM_FRM_PAD_LEN		4

#define CAIF_MAX_MTU		4096

#define SHM_SET_FULL(x)	(((x+1) & 0x0F) << 0)
#define SHM_GET_FULL(x)	(((x >> 0) & 0x0F) - 1)

#define SHM_SET_EMPTY(x)	(((x+1) & 0x0F) << 4)
#define SHM_GET_EMPTY(x)	(((x >> 4) & 0x0F) - 1)

#define SHM_FULL_MASK		(0x0F << 0)
#define SHM_EMPTY_MASK		(0x0F << 4)

struct shm_pck_desc {
	/*
	 * Offset from start of shared memory area to start of
	 * shared memory CAIF frame.
	 */
	u32 frm_ofs;
	u32 frm_len;
};

struct buf_list {
	unsigned char *desc_vptr;
	u32 phy_addr;
	u32 index;
	u32 len;
	u32 frames;
	u32 frm_ofs;
	struct list_head list;
};

struct shm_caif_frm {
	/* Number of bytes of padding before the CAIF frame. */
	u8 hdr_ofs;
};

struct shmdrv_layer {
	/* caif_dev_common must always be first in the structure*/
	struct caif_dev_common cfdev;

	u32 shm_tx_addr;
	u32 shm_rx_addr;
	u32 shm_base_addr;
	u32 tx_empty_available;
	spinlock_t lock;

	struct list_head tx_empty_list;
	struct list_head tx_pend_list;
	struct list_head tx_full_list;
	struct list_head rx_empty_list;
	struct list_head rx_pend_list;
	struct list_head rx_full_list;

	struct workqueue_struct *pshm_tx_workqueue;
	struct workqueue_struct *pshm_rx_workqueue;

	struct work_struct shm_tx_work;
	struct work_struct shm_rx_work;

	struct sk_buff_head sk_qhead;
	struct shmdev_layer *pshm_dev;
};

static int shm_netdev_open(struct net_device *shm_netdev)
{
	netif_wake_queue(shm_netdev);
	return 0;
}

static int shm_netdev_close(struct net_device *shm_netdev)
{
	netif_stop_queue(shm_netdev);
	return 0;
}

int caif_shmdrv_rx_cb(u32 mbx_msg, void *priv)
{
	struct buf_list *pbuf;
	struct shmdrv_layer *pshm_drv;
	struct list_head *pos;
	u32 avail_emptybuff = 0;
	unsigned long flags = 0;

	pshm_drv = priv;

	/* Check for received buffers. */
	if (mbx_msg & SHM_FULL_MASK) {
		int idx;

		spin_lock_irqsave(&pshm_drv->lock, flags);

		/* Check whether we have any outstanding buffers. */
		if (list_empty(&pshm_drv->rx_empty_list)) {

			/* Release spin lock. */
			spin_unlock_irqrestore(&pshm_drv->lock, flags);

			/* We print even in IRQ context... */
			pr_warn("No empty Rx buffers to fill: "
					"mbx_msg:%x\n", mbx_msg);

			/* Bail out. */
			goto err_sync;
		}

		pbuf =
			list_entry(pshm_drv->rx_empty_list.next,
					struct buf_list, list);
		idx = pbuf->index;

		/* Check buffer synchronization. */
		if (idx != SHM_GET_FULL(mbx_msg)) {

			/* We print even in IRQ context... */
			pr_warn(
			"phyif_shm_mbx_msg_cb: RX full out of sync:"
			" idx:%d, msg:%x SHM_GET_FULL(mbx_msg):%x\n",
				idx, mbx_msg, SHM_GET_FULL(mbx_msg));

			spin_unlock_irqrestore(&pshm_drv->lock, flags);

			/* Bail out. */
			goto err_sync;
		}

		list_del_init(&pbuf->list);
		list_add_tail(&pbuf->list, &pshm_drv->rx_full_list);

		spin_unlock_irqrestore(&pshm_drv->lock, flags);

		/* Schedule RX work queue. */
		if (!work_pending(&pshm_drv->shm_rx_work))
			queue_work(pshm_drv->pshm_rx_workqueue,
						&pshm_drv->shm_rx_work);
	}

	/* Check for emptied buffers. */
	if (mbx_msg & SHM_EMPTY_MASK) {
		int idx;

		spin_lock_irqsave(&pshm_drv->lock, flags);

		/* Check whether we have any outstanding buffers. */
		if (list_empty(&pshm_drv->tx_full_list)) {

			/* We print even in IRQ context... */
			pr_warn("No TX to empty: msg:%x\n", mbx_msg);

			spin_unlock_irqrestore(&pshm_drv->lock, flags);

			/* Bail out. */
			goto err_sync;
		}

		pbuf =
			list_entry(pshm_drv->tx_full_list.next,
					struct buf_list, list);
		idx = pbuf->index;

		/* Check buffer synchronization. */
		if (idx != SHM_GET_EMPTY(mbx_msg)) {

			spin_unlock_irqrestore(&pshm_drv->lock, flags);

			/* We print even in IRQ context... */
			pr_warn("TX empty "
				"out of sync:idx:%d, msg:%x\n", idx, mbx_msg);

			/* Bail out. */
			goto err_sync;
		}
		list_del_init(&pbuf->list);

		/* Reset buffer parameters. */
		pbuf->frames = 0;
		pbuf->frm_ofs = SHM_CAIF_FRM_OFS;

		list_add_tail(&pbuf->list, &pshm_drv->tx_empty_list);

		/* Check the available no. of buffers in the empty list */
		list_for_each(pos, &pshm_drv->tx_empty_list)
			avail_emptybuff++;

		/* Check whether we have to wake up the transmitter. */
		if ((avail_emptybuff > HIGH_WATERMARK) &&
					(!pshm_drv->tx_empty_available)) {
			pshm_drv->tx_empty_available = 1;
			spin_unlock_irqrestore(&pshm_drv->lock, flags);
			pshm_drv->cfdev.flowctrl
					(pshm_drv->pshm_dev->pshm_netdev,
								CAIF_FLOW_ON);


			/* Schedule the work queue. if required */
			if (!work_pending(&pshm_drv->shm_tx_work))
				queue_work(pshm_drv->pshm_tx_workqueue,
							&pshm_drv->shm_tx_work);
		} else
			spin_unlock_irqrestore(&pshm_drv->lock, flags);
	}

	return 0;

err_sync:
	return -EIO;
}

static void shm_rx_work_func(struct work_struct *rx_work)
{
	struct shmdrv_layer *pshm_drv;
	struct buf_list *pbuf;
	unsigned long flags = 0;
	struct sk_buff *skb;
	char *p;
	int ret;

	pshm_drv = container_of(rx_work, struct shmdrv_layer, shm_rx_work);

	while (1) {

		struct shm_pck_desc *pck_desc;

		spin_lock_irqsave(&pshm_drv->lock, flags);

		/* Check for received buffers. */
		if (list_empty(&pshm_drv->rx_full_list)) {
			spin_unlock_irqrestore(&pshm_drv->lock, flags);
			break;
		}

		pbuf =
			list_entry(pshm_drv->rx_full_list.next, struct buf_list,
					list);
		list_del_init(&pbuf->list);
		spin_unlock_irqrestore(&pshm_drv->lock, flags);

		/* Retrieve pointer to start of the packet descriptor area. */
		pck_desc = (struct shm_pck_desc *) pbuf->desc_vptr;

		/*
		 * Check whether descriptor contains a CAIF shared memory
		 * frame.
		 */
		while (pck_desc->frm_ofs) {
			unsigned int frm_buf_ofs;
			unsigned int frm_pck_ofs;
			unsigned int frm_pck_len;
			/*
			 * Check whether offset is within buffer limits
			 * (lower).
			 */
			if (pck_desc->frm_ofs <
				(pbuf->phy_addr - pshm_drv->shm_base_addr))
				break;
			/*
			 * Check whether offset is within buffer limits
			 * (higher).
			 */
			if (pck_desc->frm_ofs >
				((pbuf->phy_addr - pshm_drv->shm_base_addr) +
					pbuf->len))
				break;

			/* Calculate offset from start of buffer. */
			frm_buf_ofs =
				pck_desc->frm_ofs - (pbuf->phy_addr -
						pshm_drv->shm_base_addr);

			/*
			 * Calculate offset and length of CAIF packet while
			 * taking care of the shared memory header.
			 */
			frm_pck_ofs =
				frm_buf_ofs + SHM_HDR_LEN +
				(*(pbuf->desc_vptr + frm_buf_ofs));
			frm_pck_len =
				(pck_desc->frm_len - SHM_HDR_LEN -
				(*(pbuf->desc_vptr + frm_buf_ofs)));

			/* Check whether CAIF packet is within buffer limits */
			if ((frm_pck_ofs + pck_desc->frm_len) > pbuf->len)
				break;

			/* Get a suitable CAIF packet and copy in data. */
			skb = netdev_alloc_skb(pshm_drv->pshm_dev->pshm_netdev,
							frm_pck_len + 1);

			if (skb == NULL) {
				pr_info("OOM: Try next frame in descriptor\n");
				break;
			}

			p = skb_put(skb, frm_pck_len);
			memcpy(p, pbuf->desc_vptr + frm_pck_ofs, frm_pck_len);

			skb->protocol = htons(ETH_P_CAIF);
			skb_reset_mac_header(skb);
			skb->dev = pshm_drv->pshm_dev->pshm_netdev;

			/* Push received packet up the stack. */
			ret = netif_rx_ni(skb);

			if (!ret) {
				pshm_drv->pshm_dev->pshm_netdev->stats.
								rx_packets++;
				pshm_drv->pshm_dev->pshm_netdev->stats.
						rx_bytes += pck_desc->frm_len;
			} else
				++pshm_drv->pshm_dev->pshm_netdev->stats.
								rx_dropped;
			/* Move to next packet descriptor. */
			pck_desc++;
		}

		spin_lock_irqsave(&pshm_drv->lock, flags);
		list_add_tail(&pbuf->list, &pshm_drv->rx_pend_list);

		spin_unlock_irqrestore(&pshm_drv->lock, flags);

	}

	/* Schedule the work queue. if required */
	if (!work_pending(&pshm_drv->shm_tx_work))
		queue_work(pshm_drv->pshm_tx_workqueue, &pshm_drv->shm_tx_work);

}

static void shm_tx_work_func(struct work_struct *tx_work)
{
	u32 mbox_msg;
	unsigned int frmlen, avail_emptybuff, append = 0;
	unsigned long flags = 0;
	struct buf_list *pbuf = NULL;
	struct shmdrv_layer *pshm_drv;
	struct shm_caif_frm *frm;
	struct sk_buff *skb;
	struct shm_pck_desc *pck_desc;
	struct list_head *pos;

	pshm_drv = container_of(tx_work, struct shmdrv_layer, shm_tx_work);

	do {
		/* Initialize mailbox message. */
		mbox_msg = 0x00;
		avail_emptybuff = 0;

		spin_lock_irqsave(&pshm_drv->lock, flags);

		/* Check for pending receive buffers. */
		if (!list_empty(&pshm_drv->rx_pend_list)) {

			pbuf = list_entry(pshm_drv->rx_pend_list.next,
						struct buf_list, list);

			list_del_init(&pbuf->list);
			list_add_tail(&pbuf->list, &pshm_drv->rx_empty_list);
			/*
			 * Value index is never changed,
			 * so read access should be safe.
			 */
			mbox_msg |= SHM_SET_EMPTY(pbuf->index);
		}

		skb = skb_peek(&pshm_drv->sk_qhead);

		if (skb == NULL)
			goto send_msg;
		/* Check the available no. of buffers in the empty list */
		list_for_each(pos, &pshm_drv->tx_empty_list)
			avail_emptybuff++;

		if ((avail_emptybuff < LOW_WATERMARK) &&
					pshm_drv->tx_empty_available) {
			/* Update blocking condition. */
			pshm_drv->tx_empty_available = 0;
			spin_unlock_irqrestore(&pshm_drv->lock, flags);
			pshm_drv->cfdev.flowctrl
					(pshm_drv->pshm_dev->pshm_netdev,
					CAIF_FLOW_OFF);
			spin_lock_irqsave(&pshm_drv->lock, flags);
		}
		/*
		 * We simply return back to the caller if we do not have space
		 * either in Tx pending list or Tx empty list. In this case,
		 * we hold the received skb in the skb list, waiting to
		 * be transmitted once Tx buffers become available
		 */
		if (list_empty(&pshm_drv->tx_empty_list))
			goto send_msg;

		/* Get the first free Tx buffer. */
		pbuf = list_entry(pshm_drv->tx_empty_list.next,
						struct buf_list, list);
		do {
			if (append) {
				skb = skb_peek(&pshm_drv->sk_qhead);
				if (skb == NULL)
					break;
			}

			frm = (struct shm_caif_frm *)
					(pbuf->desc_vptr + pbuf->frm_ofs);

			frm->hdr_ofs = 0;
			frmlen = 0;
			frmlen += SHM_HDR_LEN + frm->hdr_ofs + skb->len;

			/* Add tail padding if needed. */
			if (frmlen % SHM_FRM_PAD_LEN)
				frmlen += SHM_FRM_PAD_LEN -
						(frmlen % SHM_FRM_PAD_LEN);

			/*
			 * Verify that packet, header and additional padding
			 * can fit within the buffer frame area.
			 */
			if (frmlen >= (pbuf->len - pbuf->frm_ofs))
				break;

			if (!append) {
				list_del_init(&pbuf->list);
				append = 1;
			}

			skb = skb_dequeue(&pshm_drv->sk_qhead);
			if (skb == NULL)
				break;
			/* Copy in CAIF frame. */
			skb_copy_bits(skb, 0, pbuf->desc_vptr +
					pbuf->frm_ofs + SHM_HDR_LEN +
						frm->hdr_ofs, skb->len);

			pshm_drv->pshm_dev->pshm_netdev->stats.tx_packets++;
			pshm_drv->pshm_dev->pshm_netdev->stats.tx_bytes +=
									frmlen;
			dev_kfree_skb_irq(skb);

			/* Fill in the shared memory packet descriptor area. */
			pck_desc = (struct shm_pck_desc *) (pbuf->desc_vptr);
			/* Forward to current frame. */
			pck_desc += pbuf->frames;
			pck_desc->frm_ofs = (pbuf->phy_addr -
						pshm_drv->shm_base_addr) +
								pbuf->frm_ofs;
			pck_desc->frm_len = frmlen;
			/* Terminate packet descriptor area. */
			pck_desc++;
			pck_desc->frm_ofs = 0;
			/* Update buffer parameters. */
			pbuf->frames++;
			pbuf->frm_ofs += frmlen + (frmlen % 32);

		} while (pbuf->frames < SHM_MAX_FRMS_PER_BUF);

		/* Assign buffer as full. */
		list_add_tail(&pbuf->list, &pshm_drv->tx_full_list);
		append = 0;
		mbox_msg |= SHM_SET_FULL(pbuf->index);
send_msg:
		spin_unlock_irqrestore(&pshm_drv->lock, flags);

		if (mbox_msg)
			pshm_drv->pshm_dev->pshmdev_mbxsend
					(pshm_drv->pshm_dev->shm_id, mbox_msg);
	} while (mbox_msg);
}

static int shm_netdev_tx(struct sk_buff *skb, struct net_device *shm_netdev)
{
	struct shmdrv_layer *pshm_drv;

	pshm_drv = netdev_priv(shm_netdev);

	skb_queue_tail(&pshm_drv->sk_qhead, skb);

	/* Schedule Tx work queue. for deferred processing of skbs*/
	if (!work_pending(&pshm_drv->shm_tx_work))
		queue_work(pshm_drv->pshm_tx_workqueue, &pshm_drv->shm_tx_work);

	return 0;
}

static const struct net_device_ops netdev_ops = {
	.ndo_open = shm_netdev_open,
	.ndo_stop = shm_netdev_close,
	.ndo_start_xmit = shm_netdev_tx,
};

static void shm_netdev_setup(struct net_device *pshm_netdev)
{
	struct shmdrv_layer *pshm_drv;
	pshm_netdev->netdev_ops = &netdev_ops;

	pshm_netdev->mtu = CAIF_MAX_MTU;
	pshm_netdev->type = ARPHRD_CAIF;
	pshm_netdev->hard_header_len = CAIF_NEEDED_HEADROOM;
	pshm_netdev->tx_queue_len = 0;
	pshm_netdev->destructor = free_netdev;

	pshm_drv = netdev_priv(pshm_netdev);

	/* Initialize structures in a clean state. */
	memset(pshm_drv, 0, sizeof(struct shmdrv_layer));

	pshm_drv->cfdev.link_select = CAIF_LINK_LOW_LATENCY;
}

int caif_shmcore_probe(struct shmdev_layer *pshm_dev)
{
	int result, j;
	struct shmdrv_layer *pshm_drv = NULL;

	pshm_dev->pshm_netdev = alloc_netdev(sizeof(struct shmdrv_layer),
						"cfshm%d", shm_netdev_setup);
	if (!pshm_dev->pshm_netdev)
		return -ENOMEM;

	pshm_drv = netdev_priv(pshm_dev->pshm_netdev);
	pshm_drv->pshm_dev = pshm_dev;

	/*
	 * Initialization starts with the verification of the
	 * availability of MBX driver by calling its setup function.
	 * MBX driver must be available by this time for proper
	 * functioning of SHM driver.
	 */
	if ((pshm_dev->pshmdev_mbxsetup
				(caif_shmdrv_rx_cb, pshm_dev, pshm_drv)) != 0) {
		pr_warn("Could not config. SHM Mailbox,"
				" Bailing out.....\n");
		free_netdev(pshm_dev->pshm_netdev);
		return -ENODEV;
	}

	skb_queue_head_init(&pshm_drv->sk_qhead);

	pr_info("SHM DEVICE[%d] PROBED BY DRIVER, NEW SHM DRIVER"
			" INSTANCE AT pshm_drv =0x%p\n",
			pshm_drv->pshm_dev->shm_id, pshm_drv);

	if (pshm_dev->shm_total_sz <
			(NR_TX_BUF * TX_BUF_SZ + NR_RX_BUF * RX_BUF_SZ)) {

		pr_warn("ERROR, Amount of available"
				" Phys. SHM cannot accommodate current SHM "
				"driver configuration, Bailing out ...\n");
		free_netdev(pshm_dev->pshm_netdev);
		return -ENOMEM;
	}

	pshm_drv->shm_base_addr = pshm_dev->shm_base_addr;
	pshm_drv->shm_tx_addr = pshm_drv->shm_base_addr;

	if (pshm_dev->shm_loopback)
		pshm_drv->shm_rx_addr = pshm_drv->shm_tx_addr;
	else
		pshm_drv->shm_rx_addr = pshm_dev->shm_base_addr +
						(NR_TX_BUF * TX_BUF_SZ);

	spin_lock_init(&pshm_drv->lock);
	INIT_LIST_HEAD(&pshm_drv->tx_empty_list);
	INIT_LIST_HEAD(&pshm_drv->tx_pend_list);
	INIT_LIST_HEAD(&pshm_drv->tx_full_list);

	INIT_LIST_HEAD(&pshm_drv->rx_empty_list);
	INIT_LIST_HEAD(&pshm_drv->rx_pend_list);
	INIT_LIST_HEAD(&pshm_drv->rx_full_list);

	INIT_WORK(&pshm_drv->shm_tx_work, shm_tx_work_func);
	INIT_WORK(&pshm_drv->shm_rx_work, shm_rx_work_func);

	pshm_drv->pshm_tx_workqueue =
				create_singlethread_workqueue("shm_tx_work");
	pshm_drv->pshm_rx_workqueue =
				create_singlethread_workqueue("shm_rx_work");

	for (j = 0; j < NR_TX_BUF; j++) {
		struct buf_list *tx_buf =
				kmalloc(sizeof(struct buf_list), GFP_KERNEL);

		if (tx_buf == NULL) {
			free_netdev(pshm_dev->pshm_netdev);
			return -ENOMEM;
		}
		tx_buf->index = j;
		tx_buf->phy_addr = pshm_drv->shm_tx_addr + (TX_BUF_SZ * j);
		tx_buf->len = TX_BUF_SZ;
		tx_buf->frames = 0;
		tx_buf->frm_ofs = SHM_CAIF_FRM_OFS;

		if (pshm_dev->shm_loopback)
			tx_buf->desc_vptr = (unsigned char *)tx_buf->phy_addr;
		else
			/*
			 * FIXME: the result of ioremap is not a pointer - arnd
			 */
			tx_buf->desc_vptr =
					ioremap(tx_buf->phy_addr, TX_BUF_SZ);

		list_add_tail(&tx_buf->list, &pshm_drv->tx_empty_list);
	}

	for (j = 0; j < NR_RX_BUF; j++) {
		struct buf_list *rx_buf =
				kmalloc(sizeof(struct buf_list), GFP_KERNEL);

		if (rx_buf == NULL) {
			free_netdev(pshm_dev->pshm_netdev);
			return -ENOMEM;
		}
		rx_buf->index = j;
		rx_buf->phy_addr = pshm_drv->shm_rx_addr + (RX_BUF_SZ * j);
		rx_buf->len = RX_BUF_SZ;

		if (pshm_dev->shm_loopback)
			rx_buf->desc_vptr = (unsigned char *)rx_buf->phy_addr;
		else
			rx_buf->desc_vptr =
					ioremap(rx_buf->phy_addr, RX_BUF_SZ);
		list_add_tail(&rx_buf->list, &pshm_drv->rx_empty_list);
	}

	pshm_drv->tx_empty_available = 1;
	result = register_netdev(pshm_dev->pshm_netdev);
	if (result)
		pr_warn("ERROR[%d], SHM could not, "
			"register with NW FRMWK Bailing out ...\n", result);

	return result;
}

void caif_shmcore_remove(struct net_device *pshm_netdev)
{
	struct buf_list *pbuf;
	struct shmdrv_layer *pshm_drv = NULL;

	pshm_drv = netdev_priv(pshm_netdev);

	while (!(list_empty(&pshm_drv->tx_pend_list))) {
		pbuf =
			list_entry(pshm_drv->tx_pend_list.next,
					struct buf_list, list);

		list_del(&pbuf->list);
		kfree(pbuf);
	}

	while (!(list_empty(&pshm_drv->tx_full_list))) {
		pbuf =
			list_entry(pshm_drv->tx_full_list.next,
					struct buf_list, list);
		list_del(&pbuf->list);
		kfree(pbuf);
	}

	while (!(list_empty(&pshm_drv->tx_empty_list))) {
		pbuf =
			list_entry(pshm_drv->tx_empty_list.next,
					struct buf_list, list);
		list_del(&pbuf->list);
		kfree(pbuf);
	}

	while (!(list_empty(&pshm_drv->rx_full_list))) {
		pbuf =
			list_entry(pshm_drv->tx_full_list.next,
				struct buf_list, list);
		list_del(&pbuf->list);
		kfree(pbuf);
	}

	while (!(list_empty(&pshm_drv->rx_pend_list))) {
		pbuf =
			list_entry(pshm_drv->tx_pend_list.next,
				struct buf_list, list);
		list_del(&pbuf->list);
		kfree(pbuf);
	}

	while (!(list_empty(&pshm_drv->rx_empty_list))) {
		pbuf =
			list_entry(pshm_drv->rx_empty_list.next,
				struct buf_list, list);
		list_del(&pbuf->list);
		kfree(pbuf);
	}

	/* Destroy work queues. */
	destroy_workqueue(pshm_drv->pshm_tx_workqueue);
	destroy_workqueue(pshm_drv->pshm_rx_workqueue);

	unregister_netdev(pshm_netdev);
}