summaryrefslogtreecommitdiffstats
path: root/drivers/hsi/clients/hsi_char.c
blob: 9d2a6d64dfb80c0dedbd472a1df9d4f38d540539 (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
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
/*
 * HSI character device driver, implements the character device
 * interface.
 *
 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
 *
 * Contact: Andras Domokos <andras.domokos@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/kmemleak.h>
#include <linux/ioctl.h>
#include <linux/wait.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/uaccess.h>
#include <linux/scatterlist.h>
#include <linux/stat.h>
#include <linux/hsi/hsi.h>
#include <linux/hsi/hsi_char.h>

#define HSC_DEVS		16 /* Num of channels */
#define HSC_MSGS		4

#define HSC_RXBREAK		0

#define HSC_ID_BITS		6
#define HSC_PORT_ID_BITS	4
#define HSC_ID_MASK		3
#define HSC_PORT_ID_MASK	3
#define HSC_CH_MASK		0xf

/*
 * We support up to 4 controllers that can have up to 4
 * ports, which should currently be more than enough.
 */
#define HSC_BASEMINOR(id, port_id) \
		((((id) & HSC_ID_MASK) << HSC_ID_BITS) | \
		(((port_id) & HSC_PORT_ID_MASK) << HSC_PORT_ID_BITS))

enum {
	HSC_CH_OPEN,
	HSC_CH_READ,
	HSC_CH_WRITE,
	HSC_CH_WLINE,
};

enum {
	HSC_RX,
	HSC_TX,
};

struct hsc_client_data;
/**
 * struct hsc_channel - hsi_char internal channel data
 * @ch: channel number
 * @flags: Keeps state of the channel (open/close, reading, writing)
 * @free_msgs_list: List of free HSI messages/requests
 * @rx_msgs_queue: List of pending RX requests
 * @tx_msgs_queue: List of pending TX requests
 * @lock: Serialize access to the lists
 * @cl: reference to the associated hsi_client
 * @cl_data: reference to the client data that this channels belongs to
 * @rx_wait: RX requests wait queue
 * @tx_wait: TX requests wait queue
 */
struct hsc_channel {
	unsigned int		ch;
	unsigned long		flags;
	struct list_head	free_msgs_list;
	struct list_head	rx_msgs_queue;
	struct list_head	tx_msgs_queue;
	spinlock_t		lock;
	struct hsi_client	*cl;
	struct hsc_client_data *cl_data;
	wait_queue_head_t	rx_wait;
	wait_queue_head_t	tx_wait;
};

/**
 * struct hsc_client_data - hsi_char internal client data
 * @cdev: Characther device associated to the hsi_client
 * @lock: Lock to serialize open/close access
 * @flags: Keeps track of port state (rx hwbreak armed)
 * @usecnt: Use count for claiming the HSI port (mutex protected)
 * @cl: Referece to the HSI client
 * @channels: Array of channels accessible by the client
 */
struct hsc_client_data {
	struct cdev		cdev;
	struct mutex		lock;
	unsigned long		flags;
	unsigned int		usecnt;
	struct hsi_client	*cl;
	struct hsc_channel	channels[HSC_DEVS];
};

/* Stores the major number dynamically allocated for hsi_char */
static unsigned int hsc_major;
/* Maximum buffer size that hsi_char will accept from userspace */
static unsigned int max_data_size = 0x1000;
module_param(max_data_size, uint, 0);
MODULE_PARM_DESC(max_data_size, "max read/write data size [4,8..65536] (^2)");

static void hsc_add_tail(struct hsc_channel *channel, struct hsi_msg *msg,
							struct list_head *queue)
{
	unsigned long flags;

	spin_lock_irqsave(&channel->lock, flags);
	list_add_tail(&msg->link, queue);
	spin_unlock_irqrestore(&channel->lock, flags);
}

static struct hsi_msg *hsc_get_first_msg(struct hsc_channel *channel,
							struct list_head *queue)
{
	struct hsi_msg *msg = NULL;
	unsigned long flags;

	spin_lock_irqsave(&channel->lock, flags);

	if (list_empty(queue))
		goto out;

	msg = list_first_entry(queue, struct hsi_msg, link);
	list_del(&msg->link);
out:
	spin_unlock_irqrestore(&channel->lock, flags);

	return msg;
}

static inline void hsc_msg_free(struct hsi_msg *msg)
{
	kfree(sg_virt(msg->sgt.sgl));
	hsi_free_msg(msg);
}

static void hsc_free_list(struct list_head *list)
{
	struct hsi_msg *msg, *tmp;

	list_for_each_entry_safe(msg, tmp, list, link) {
		list_del(&msg->link);
		hsc_msg_free(msg);
	}
}

static void hsc_reset_list(struct hsc_channel *channel, struct list_head *l)
{
	unsigned long flags;
	LIST_HEAD(list);

	spin_lock_irqsave(&channel->lock, flags);
	list_splice_init(l, &list);
	spin_unlock_irqrestore(&channel->lock, flags);

	hsc_free_list(&list);
}

static inline struct hsi_msg *hsc_msg_alloc(unsigned int alloc_size)
{
	struct hsi_msg *msg;
	void *buf;

	msg = hsi_alloc_msg(1, GFP_KERNEL);
	if (!msg)
		goto out;
	buf = kmalloc(alloc_size, GFP_KERNEL);
	if (!buf) {
		hsi_free_msg(msg);
		goto out;
	}
	sg_init_one(msg->sgt.sgl, buf, alloc_size);
	/* Ignore false positive, due to sg pointer handling */
	kmemleak_ignore(buf);

	return msg;
out:
	return NULL;
}

static inline int hsc_msgs_alloc(struct hsc_channel *channel)
{
	struct hsi_msg *msg;
	int i;

	for (i = 0; i < HSC_MSGS; i++) {
		msg = hsc_msg_alloc(max_data_size);
		if (!msg)
			goto out;
		msg->channel = channel->ch;
		list_add_tail(&msg->link, &channel->free_msgs_list);
	}

	return 0;
out:
	hsc_free_list(&channel->free_msgs_list);

	return -ENOMEM;
}

static inline unsigned int hsc_msg_len_get(struct hsi_msg *msg)
{
	return msg->sgt.sgl->length;
}

static inline void hsc_msg_len_set(struct hsi_msg *msg, unsigned int len)
{
	msg->sgt.sgl->length = len;
}

static void hsc_rx_completed(struct hsi_msg *msg)
{
	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
	struct hsc_channel *channel = cl_data->channels + msg->channel;

	if (test_bit(HSC_CH_READ, &channel->flags)) {
		hsc_add_tail(channel, msg, &channel->rx_msgs_queue);
		wake_up(&channel->rx_wait);
	} else {
		hsc_add_tail(channel, msg, &channel->free_msgs_list);
	}
}

static void hsc_rx_msg_destructor(struct hsi_msg *msg)
{
	msg->status = HSI_STATUS_ERROR;
	hsc_msg_len_set(msg, 0);
	hsc_rx_completed(msg);
}

static void hsc_tx_completed(struct hsi_msg *msg)
{
	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
	struct hsc_channel *channel = cl_data->channels + msg->channel;

	if (test_bit(HSC_CH_WRITE, &channel->flags)) {
		hsc_add_tail(channel, msg, &channel->tx_msgs_queue);
		wake_up(&channel->tx_wait);
	} else {
		hsc_add_tail(channel, msg, &channel->free_msgs_list);
	}
}

static void hsc_tx_msg_destructor(struct hsi_msg *msg)
{
	msg->status = HSI_STATUS_ERROR;
	hsc_msg_len_set(msg, 0);
	hsc_tx_completed(msg);
}

static void hsc_break_req_destructor(struct hsi_msg *msg)
{
	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);

	hsi_free_msg(msg);
	clear_bit(HSC_RXBREAK, &cl_data->flags);
}

static void hsc_break_received(struct hsi_msg *msg)
{
	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
	struct hsc_channel *channel = cl_data->channels;
	int i, ret;

	/* Broadcast HWBREAK on all channels */
	for (i = 0; i < HSC_DEVS; i++, channel++) {
		struct hsi_msg *msg2;

		if (!test_bit(HSC_CH_READ, &channel->flags))
			continue;
		msg2 = hsc_get_first_msg(channel, &channel->free_msgs_list);
		if (!msg2)
			continue;
		clear_bit(HSC_CH_READ, &channel->flags);
		hsc_msg_len_set(msg2, 0);
		msg2->status = HSI_STATUS_COMPLETED;
		hsc_add_tail(channel, msg2, &channel->rx_msgs_queue);
		wake_up(&channel->rx_wait);
	}
	hsi_flush(msg->cl);
	ret = hsi_async_read(msg->cl, msg);
	if (ret < 0)
		hsc_break_req_destructor(msg);
}

static int hsc_break_request(struct hsi_client *cl)
{
	struct hsc_client_data *cl_data = hsi_client_drvdata(cl);
	struct hsi_msg *msg;
	int ret;

	if (test_and_set_bit(HSC_RXBREAK, &cl_data->flags))
		return -EBUSY;

	msg = hsi_alloc_msg(0, GFP_KERNEL);
	if (!msg) {
		clear_bit(HSC_RXBREAK, &cl_data->flags);
		return -ENOMEM;
	}
	msg->break_frame = 1;
	msg->complete = hsc_break_received;
	msg->destructor = hsc_break_req_destructor;
	ret = hsi_async_read(cl, msg);
	if (ret < 0)
		hsc_break_req_destructor(msg);

	return ret;
}

static int hsc_break_send(struct hsi_client *cl)
{
	struct hsi_msg *msg;
	int ret;

	msg = hsi_alloc_msg(0, GFP_ATOMIC);
	if (!msg)
		return -ENOMEM;
	msg->break_frame = 1;
	msg->complete = hsi_free_msg;
	msg->destructor = hsi_free_msg;
	ret = hsi_async_write(cl, msg);
	if (ret < 0)
		hsi_free_msg(msg);

	return ret;
}

static int hsc_rx_set(struct hsi_client *cl, struct hsc_rx_config *rxc)
{
	struct hsi_config tmp;
	int ret;

	if ((rxc->mode != HSI_MODE_STREAM) && (rxc->mode != HSI_MODE_FRAME))
		return -EINVAL;
	if ((rxc->channels == 0) || (rxc->channels > HSC_DEVS))
		return -EINVAL;
	if (rxc->channels & (rxc->channels - 1))
		return -EINVAL;
	if ((rxc->flow != HSI_FLOW_SYNC) && (rxc->flow != HSI_FLOW_PIPE))
		return -EINVAL;
	tmp = cl->rx_cfg;
	cl->rx_cfg.mode = rxc->mode;
	cl->rx_cfg.num_hw_channels = rxc->channels;
	cl->rx_cfg.flow = rxc->flow;
	ret = hsi_setup(cl);
	if (ret < 0) {
		cl->rx_cfg = tmp;
		return ret;
	}
	if (rxc->mode == HSI_MODE_FRAME)
		hsc_break_request(cl);

	return ret;
}

static inline void hsc_rx_get(struct hsi_client *cl, struct hsc_rx_config *rxc)
{
	rxc->mode = cl->rx_cfg.mode;
	rxc->channels = cl->rx_cfg.num_hw_channels;
	rxc->flow = cl->rx_cfg.flow;
}

static int hsc_tx_set(struct hsi_client *cl, struct hsc_tx_config *txc)
{
	struct hsi_config tmp;
	int ret;

	if ((txc->mode != HSI_MODE_STREAM) && (txc->mode != HSI_MODE_FRAME))
		return -EINVAL;
	if ((txc->channels == 0) || (txc->channels > HSC_DEVS))
		return -EINVAL;
	if (txc->channels & (txc->channels - 1))
		return -EINVAL;
	if ((txc->arb_mode != HSI_ARB_RR) && (txc->arb_mode != HSI_ARB_PRIO))
		return -EINVAL;
	tmp = cl->tx_cfg;
	cl->tx_cfg.mode = txc->mode;
	cl->tx_cfg.num_hw_channels = txc->channels;
	cl->tx_cfg.speed = txc->speed;
	cl->tx_cfg.arb_mode = txc->arb_mode;
	ret = hsi_setup(cl);
	if (ret < 0) {
		cl->tx_cfg = tmp;
		return ret;
	}

	return ret;
}

static inline void hsc_tx_get(struct hsi_client *cl, struct hsc_tx_config *txc)
{
	txc->mode = cl->tx_cfg.mode;
	txc->channels = cl->tx_cfg.num_hw_channels;
	txc->speed = cl->tx_cfg.speed;
	txc->arb_mode = cl->tx_cfg.arb_mode;
}

static ssize_t hsc_read(struct file *file, char __user *buf, size_t len,
						loff_t *ppos __maybe_unused)
{
	struct hsc_channel *channel = file->private_data;
	struct hsi_msg *msg;
	ssize_t ret;

	if (len == 0)
		return 0;
	if (!IS_ALIGNED(len, sizeof(u32)))
		return -EINVAL;
	if (len > max_data_size)
		len = max_data_size;
	if (channel->ch >= channel->cl->rx_cfg.num_hw_channels)
		return -ECHRNG;
	if (test_and_set_bit(HSC_CH_READ, &channel->flags))
		return -EBUSY;
	msg = hsc_get_first_msg(channel, &channel->free_msgs_list);
	if (!msg) {
		ret = -ENOSPC;
		goto out;
	}
	hsc_msg_len_set(msg, len);
	msg->complete = hsc_rx_completed;
	msg->destructor = hsc_rx_msg_destructor;
	ret = hsi_async_read(channel->cl, msg);
	if (ret < 0) {
		hsc_add_tail(channel, msg, &channel->free_msgs_list);
		goto out;
	}

	ret = wait_event_interruptible(channel->rx_wait,
					!list_empty(&channel->rx_msgs_queue));
	if (ret < 0) {
		clear_bit(HSC_CH_READ, &channel->flags);
		hsi_flush(channel->cl);
		return -EINTR;
	}

	msg = hsc_get_first_msg(channel, &channel->rx_msgs_queue);
	if (msg) {
		if (msg->status != HSI_STATUS_ERROR) {
			ret = copy_to_user((void __user *)buf,
			sg_virt(msg->sgt.sgl), hsc_msg_len_get(msg));
			if (ret)
				ret = -EFAULT;
			else
				ret = hsc_msg_len_get(msg);
		} else {
			ret = -EIO;
		}
		hsc_add_tail(channel, msg, &channel->free_msgs_list);
	}
out:
	clear_bit(HSC_CH_READ, &channel->flags);

	return ret;
}

static ssize_t hsc_write(struct file *file, const char __user *buf, size_t len,
						loff_t *ppos __maybe_unused)
{
	struct hsc_channel *channel = file->private_data;
	struct hsi_msg *msg;
	ssize_t ret;

	if ((len == 0) || !IS_ALIGNED(len, sizeof(u32)))
		return -EINVAL;
	if (len > max_data_size)
		len = max_data_size;
	if (channel->ch >= channel->cl->tx_cfg.num_hw_channels)
		return -ECHRNG;
	if (test_and_set_bit(HSC_CH_WRITE, &channel->flags))
		return -EBUSY;
	msg = hsc_get_first_msg(channel, &channel->free_msgs_list);
	if (!msg) {
		clear_bit(HSC_CH_WRITE, &channel->flags);
		return -ENOSPC;
	}
	if (copy_from_user(sg_virt(msg->sgt.sgl), (void __user *)buf, len)) {
		ret = -EFAULT;
		goto out;
	}
	hsc_msg_len_set(msg, len);
	msg->complete = hsc_tx_completed;
	msg->destructor = hsc_tx_msg_destructor;
	ret = hsi_async_write(channel->cl, msg);
	if (ret < 0)
		goto out;

	ret = wait_event_interruptible(channel->tx_wait,
					!list_empty(&channel->tx_msgs_queue));
	if (ret < 0) {
		clear_bit(HSC_CH_WRITE, &channel->flags);
		hsi_flush(channel->cl);
		return -EINTR;
	}

	msg = hsc_get_first_msg(channel, &channel->tx_msgs_queue);
	if (msg) {
		if (msg->status == HSI_STATUS_ERROR)
			ret = -EIO;
		else
			ret = hsc_msg_len_get(msg);

		hsc_add_tail(channel, msg, &channel->free_msgs_list);
	}
out:
	clear_bit(HSC_CH_WRITE, &channel->flags);

	return ret;
}

static long hsc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct hsc_channel *channel = file->private_data;
	unsigned int state;
	struct hsc_rx_config rxc;
	struct hsc_tx_config txc;
	long ret = 0;

	switch (cmd) {
	case HSC_RESET:
		hsi_flush(channel->cl);
		break;
	case HSC_SET_PM:
		if (copy_from_user(&state, (void __user *)arg, sizeof(state)))
			return -EFAULT;
		if (state == HSC_PM_DISABLE) {
			if (test_and_set_bit(HSC_CH_WLINE, &channel->flags))
				return -EINVAL;
			ret = hsi_start_tx(channel->cl);
		} else if (state == HSC_PM_ENABLE) {
			if (!test_and_clear_bit(HSC_CH_WLINE, &channel->flags))
				return -EINVAL;
			ret = hsi_stop_tx(channel->cl);
		} else {
			ret = -EINVAL;
		}
		break;
	case HSC_SEND_BREAK:
		return hsc_break_send(channel->cl);
	case HSC_SET_RX:
		if (copy_from_user(&rxc, (void __user *)arg, sizeof(rxc)))
			return -EFAULT;
		return hsc_rx_set(channel->cl, &rxc);
	case HSC_GET_RX:
		hsc_rx_get(channel->cl, &rxc);
		if (copy_to_user((void __user *)arg, &rxc, sizeof(rxc)))
			return -EFAULT;
		break;
	case HSC_SET_TX:
		if (copy_from_user(&txc, (void __user *)arg, sizeof(txc)))
			return -EFAULT;
		return hsc_tx_set(channel->cl, &txc);
	case HSC_GET_TX:
		hsc_tx_get(channel->cl, &txc);
		if (copy_to_user((void __user *)arg, &txc, sizeof(txc)))
			return -EFAULT;
		break;
	default:
		return -ENOIOCTLCMD;
	}

	return ret;
}

static inline void __hsc_port_release(struct hsc_client_data *cl_data)
{
	BUG_ON(cl_data->usecnt == 0);

	if (--cl_data->usecnt == 0) {
		hsi_flush(cl_data->cl);
		hsi_release_port(cl_data->cl);
	}
}

static int hsc_open(struct inode *inode, struct file *file)
{
	struct hsc_client_data *cl_data;
	struct hsc_channel *channel;
	int ret = 0;

	pr_debug("open, minor = %d\n", iminor(inode));

	cl_data = container_of(inode->i_cdev, struct hsc_client_data, cdev);
	mutex_lock(&cl_data->lock);
	channel = cl_data->channels + (iminor(inode) & HSC_CH_MASK);

	if (test_and_set_bit(HSC_CH_OPEN, &channel->flags)) {
		ret = -EBUSY;
		goto out;
	}
	/*
	 * Check if we have already claimed the port associated to the HSI
	 * client. If not then try to claim it, else increase its refcount
	 */
	if (cl_data->usecnt == 0) {
		ret = hsi_claim_port(cl_data->cl, 0);
		if (ret < 0)
			goto out;
		hsi_setup(cl_data->cl);
	}
	cl_data->usecnt++;

	ret = hsc_msgs_alloc(channel);
	if (ret < 0) {
		__hsc_port_release(cl_data);
		goto out;
	}

	file->private_data = channel;
	mutex_unlock(&cl_data->lock);

	return ret;
out:
	mutex_unlock(&cl_data->lock);

	return ret;
}

static int hsc_release(struct inode *inode __maybe_unused, struct file *file)
{
	struct hsc_channel *channel = file->private_data;
	struct hsc_client_data *cl_data = channel->cl_data;

	mutex_lock(&cl_data->lock);
	file->private_data = NULL;
	if (test_and_clear_bit(HSC_CH_WLINE, &channel->flags))
		hsi_stop_tx(channel->cl);
	__hsc_port_release(cl_data);
	hsc_reset_list(channel, &channel->rx_msgs_queue);
	hsc_reset_list(channel, &channel->tx_msgs_queue);
	hsc_reset_list(channel, &channel->free_msgs_list);
	clear_bit(HSC_CH_READ, &channel->flags);
	clear_bit(HSC_CH_WRITE, &channel->flags);
	clear_bit(HSC_CH_OPEN, &channel->flags);
	wake_up(&channel->rx_wait);
	wake_up(&channel->tx_wait);
	mutex_unlock(&cl_data->lock);

	return 0;
}

static const struct file_operations hsc_fops = {
	.owner		= THIS_MODULE,
	.read		= hsc_read,
	.write		= hsc_write,
	.unlocked_ioctl	= hsc_ioctl,
	.open		= hsc_open,
	.release	= hsc_release,
};

static void hsc_channel_init(struct hsc_channel *channel)
{
	init_waitqueue_head(&channel->rx_wait);
	init_waitqueue_head(&channel->tx_wait);
	spin_lock_init(&channel->lock);
	INIT_LIST_HEAD(&channel->free_msgs_list);
	INIT_LIST_HEAD(&channel->rx_msgs_queue);
	INIT_LIST_HEAD(&channel->tx_msgs_queue);
}

static int hsc_probe(struct device *dev)
{
	const char devname[] = "hsi_char";
	struct hsc_client_data *cl_data;
	struct hsc_channel *channel;
	struct hsi_client *cl = to_hsi_client(dev);
	unsigned int hsc_baseminor;
	dev_t hsc_dev;
	int ret;
	int i;

	cl_data = kzalloc(sizeof(*cl_data), GFP_KERNEL);
	if (!cl_data)
		return -ENOMEM;

	hsc_baseminor = HSC_BASEMINOR(hsi_id(cl), hsi_port_id(cl));
	if (!hsc_major) {
		ret = alloc_chrdev_region(&hsc_dev, hsc_baseminor,
						HSC_DEVS, devname);
		if (ret == 0)
			hsc_major = MAJOR(hsc_dev);
	} else {
		hsc_dev = MKDEV(hsc_major, hsc_baseminor);
		ret = register_chrdev_region(hsc_dev, HSC_DEVS, devname);
	}
	if (ret < 0) {
		dev_err(dev, "Device %s allocation failed %d\n",
					hsc_major ? "minor" : "major", ret);
		goto out1;
	}
	mutex_init(&cl_data->lock);
	hsi_client_set_drvdata(cl, cl_data);
	cdev_init(&cl_data->cdev, &hsc_fops);
	cl_data->cdev.owner = THIS_MODULE;
	cl_data->cl = cl;
	for (i = 0, channel = cl_data->channels; i < HSC_DEVS; i++, channel++) {
		hsc_channel_init(channel);
		channel->ch = i;
		channel->cl = cl;
		channel->cl_data = cl_data;
	}

	/* 1 hsi client -> N char devices (one for each channel) */
	ret = cdev_add(&cl_data->cdev, hsc_dev, HSC_DEVS);
	if (ret) {
		dev_err(dev, "Could not add char device %d\n", ret);
		goto out2;
	}

	return 0;
out2:
	unregister_chrdev_region(hsc_dev, HSC_DEVS);
out1:
	kfree(cl_data);

	return ret;
}

static int hsc_remove(struct device *dev)
{
	struct hsi_client *cl = to_hsi_client(dev);
	struct hsc_client_data *cl_data = hsi_client_drvdata(cl);
	dev_t hsc_dev = cl_data->cdev.dev;

	cdev_del(&cl_data->cdev);
	unregister_chrdev_region(hsc_dev, HSC_DEVS);
	hsi_client_set_drvdata(cl, NULL);
	kfree(cl_data);

	return 0;
}

static struct hsi_client_driver hsc_driver = {
	.driver = {
		.name	= "hsi_char",
		.owner	= THIS_MODULE,
		.probe	= hsc_probe,
		.remove	= hsc_remove,
	},
};

static int __init hsc_init(void)
{
	int ret;

	if ((max_data_size < 4) || (max_data_size > 0x10000) ||
		(max_data_size & (max_data_size - 1))) {
		pr_err("Invalid max read/write data size\n");
		return -EINVAL;
	}

	ret = hsi_register_client_driver(&hsc_driver);
	if (ret) {
		pr_err("Error while registering HSI/SSI driver %d\n", ret);
		return ret;
	}

	pr_info("HSI/SSI char device loaded\n");

	return 0;
}
module_init(hsc_init);

static void __exit hsc_exit(void)
{
	hsi_unregister_client_driver(&hsc_driver);
	pr_info("HSI char device removed\n");
}
module_exit(hsc_exit);

MODULE_AUTHOR("Andras Domokos <andras.domokos@nokia.com>");
MODULE_ALIAS("hsi:hsi_char");
MODULE_DESCRIPTION("HSI character device");
MODULE_LICENSE("GPL v2");