summaryrefslogtreecommitdiff
path: root/drivers/hid/intel-ish-hid/ishtp/bus.c
blob: 5f382fedc2abfaa468595dc5296a650c00525333 (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
/*
 * ISHTP bus driver
 *
 * Copyright (c) 2012-2016, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "bus.h"
#include "ishtp-dev.h"
#include "client.h"
#include "hbm.h"

static int ishtp_use_dma;
module_param_named(ishtp_use_dma, ishtp_use_dma, int, 0600);
MODULE_PARM_DESC(ishtp_use_dma, "Use DMA to send messages");

#define to_ishtp_cl_driver(d) container_of(d, struct ishtp_cl_driver, driver)
#define to_ishtp_cl_device(d) container_of(d, struct ishtp_cl_device, dev)
static bool ishtp_device_ready;

/**
 * ishtp_recv() - process ishtp message
 * @dev: ishtp device
 *
 * If a message with valid header and size is received, then
 * this function calls appropriate handler. The host or firmware
 * address is zero, then they are host bus management message,
 * otherwise they are message fo clients.
 */
void ishtp_recv(struct ishtp_device *dev)
{
	uint32_t	msg_hdr;
	struct ishtp_msg_hdr	*ishtp_hdr;

	/* Read ISHTP header dword */
	msg_hdr = dev->ops->ishtp_read_hdr(dev);
	if (!msg_hdr)
		return;

	dev->ops->sync_fw_clock(dev);

	ishtp_hdr = (struct ishtp_msg_hdr *)&msg_hdr;
	dev->ishtp_msg_hdr = msg_hdr;

	/* Sanity check: ISHTP frag. length in header */
	if (ishtp_hdr->length > dev->mtu) {
		dev_err(dev->devc,
			"ISHTP hdr - bad length: %u; dropped [%08X]\n",
			(unsigned int)ishtp_hdr->length, msg_hdr);
		return;
	}

	/* ISHTP bus message */
	if (!ishtp_hdr->host_addr && !ishtp_hdr->fw_addr)
		recv_hbm(dev, ishtp_hdr);
	/* ISHTP fixed-client message */
	else if (!ishtp_hdr->host_addr)
		recv_fixed_cl_msg(dev, ishtp_hdr);
	else
		/* ISHTP client message */
		recv_ishtp_cl_msg(dev, ishtp_hdr);
}
EXPORT_SYMBOL(ishtp_recv);

/**
 * ishtp_send_msg() - Send ishtp message
 * @dev: ishtp device
 * @hdr: Message header
 * @msg: Message contents
 * @ipc_send_compl: completion callback
 * @ipc_send_compl_prm: completion callback parameter
 *
 * Send a multi fragment message via IPC. After sending the first fragment
 * the completion callback is called to schedule transmit of next fragment.
 *
 * Return: This returns IPC send message status.
 */
int ishtp_send_msg(struct ishtp_device *dev, struct ishtp_msg_hdr *hdr,
		       void *msg, void(*ipc_send_compl)(void *),
		       void *ipc_send_compl_prm)
{
	unsigned char	ipc_msg[IPC_FULL_MSG_SIZE];
	uint32_t	drbl_val;

	drbl_val = dev->ops->ipc_get_header(dev, hdr->length +
					    sizeof(struct ishtp_msg_hdr),
					    1);

	memcpy(ipc_msg, &drbl_val, sizeof(uint32_t));
	memcpy(ipc_msg + sizeof(uint32_t), hdr, sizeof(uint32_t));
	memcpy(ipc_msg + 2 * sizeof(uint32_t), msg, hdr->length);
	return	dev->ops->write(dev, ipc_send_compl, ipc_send_compl_prm,
				ipc_msg, 2 * sizeof(uint32_t) + hdr->length);
}

/**
 * ishtp_write_message() - Send ishtp single fragment message
 * @dev: ishtp device
 * @hdr: Message header
 * @buf: message data
 *
 * Send a single fragment message via IPC.  This returns IPC send message
 * status.
 *
 * Return: This returns IPC send message status.
 */
int ishtp_write_message(struct ishtp_device *dev, struct ishtp_msg_hdr *hdr,
			unsigned char *buf)
{
	return ishtp_send_msg(dev, hdr, buf, NULL, NULL);
}

/**
 * ishtp_fw_cl_by_uuid() - locate index of fw client
 * @dev: ishtp device
 * @uuid: uuid of the client to search
 *
 * Search firmware client using UUID.
 *
 * Return: fw client index or -ENOENT if not found
 */
int ishtp_fw_cl_by_uuid(struct ishtp_device *dev, const uuid_le *uuid)
{
	int i, res = -ENOENT;

	for (i = 0; i < dev->fw_clients_num; ++i) {
		if (uuid_le_cmp(*uuid, dev->fw_clients[i].props.protocol_name)
				== 0) {
			res = i;
			break;
		}
	}
	return res;
}
EXPORT_SYMBOL(ishtp_fw_cl_by_uuid);

/**
 * ishtp_fw_cl_by_id() - return index to fw_clients for client_id
 * @dev: the ishtp device structure
 * @client_id: fw client id to search
 *
 * Search firmware client using client id.
 *
 * Return: index on success, -ENOENT on failure.
 */
int ishtp_fw_cl_by_id(struct ishtp_device *dev, uint8_t client_id)
{
	int i, res = -ENOENT;
	unsigned long	flags;

	spin_lock_irqsave(&dev->fw_clients_lock, flags);
	for (i = 0; i < dev->fw_clients_num; i++) {
		if (dev->fw_clients[i].client_id == client_id) {
			res = i;
			break;
		}
	}
	spin_unlock_irqrestore(&dev->fw_clients_lock, flags);

	return res;
}

/**
 * ishtp_cl_device_probe() - Bus probe() callback
 * @dev: the device structure
 *
 * This is a bus probe callback and calls the drive probe function.
 *
 * Return: Return value from driver probe() call.
 */
static int ishtp_cl_device_probe(struct device *dev)
{
	struct ishtp_cl_device *device = to_ishtp_cl_device(dev);
	struct ishtp_cl_driver *driver;

	if (!device)
		return 0;

	driver = to_ishtp_cl_driver(dev->driver);
	if (!driver || !driver->probe)
		return -ENODEV;

	return driver->probe(device);
}

/**
 * ishtp_cl_device_remove() - Bus remove() callback
 * @dev: the device structure
 *
 * This is a bus remove callback and calls the drive remove function.
 * Since the ISH driver model supports only built in, this is
 * primarily can be called during pci driver init failure.
 *
 * Return: Return value from driver remove() call.
 */
static int ishtp_cl_device_remove(struct device *dev)
{
	struct ishtp_cl_device *device = to_ishtp_cl_device(dev);
	struct ishtp_cl_driver *driver;

	if (!device || !dev->driver)
		return 0;

	if (device->event_cb) {
		device->event_cb = NULL;
		cancel_work_sync(&device->event_work);
	}

	driver = to_ishtp_cl_driver(dev->driver);
	if (!driver->remove) {
		dev->driver = NULL;

		return 0;
	}

	return driver->remove(device);
}

/**
 * ishtp_cl_device_suspend() - Bus suspend callback
 * @dev:	device
 *
 * Called during device suspend process.
 *
 * Return: Return value from driver suspend() call.
 */
static int ishtp_cl_device_suspend(struct device *dev)
{
	struct ishtp_cl_device *device = to_ishtp_cl_device(dev);
	struct ishtp_cl_driver *driver;
	int ret = 0;

	if (!device)
		return 0;

	driver = to_ishtp_cl_driver(dev->driver);
	if (driver && driver->driver.pm) {
		if (driver->driver.pm->suspend)
			ret = driver->driver.pm->suspend(dev);
	}

	return ret;
}

/**
 * ishtp_cl_device_resume() - Bus resume callback
 * @dev:	device
 *
 * Called during device resume process.
 *
 * Return: Return value from driver resume() call.
 */
static int ishtp_cl_device_resume(struct device *dev)
{
	struct ishtp_cl_device *device = to_ishtp_cl_device(dev);
	struct ishtp_cl_driver *driver;
	int ret = 0;

	if (!device)
		return 0;

	/*
	 * When ISH needs hard reset, it is done asynchrnously, hence bus
	 * resume will  be called before full ISH resume
	 */
	if (device->ishtp_dev->resume_flag)
		return 0;

	driver = to_ishtp_cl_driver(dev->driver);
	if (driver && driver->driver.pm) {
		if (driver->driver.pm->resume)
			ret = driver->driver.pm->resume(dev);
	}

	return ret;
}

/**
 * ishtp_cl_device_reset() - Reset callback
 * @device:	ishtp client device instance
 *
 * This is a callback when HW reset is done and the device need
 * reinit.
 *
 * Return: Return value from driver reset() call.
 */
static int ishtp_cl_device_reset(struct ishtp_cl_device *device)
{
	struct ishtp_cl_driver *driver;
	int ret = 0;

	device->event_cb = NULL;
	cancel_work_sync(&device->event_work);

	driver = to_ishtp_cl_driver(device->dev.driver);
	if (driver && driver->reset)
		ret = driver->reset(device);

	return ret;
}

static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
	char *buf)
{
	int len;

	len = snprintf(buf, PAGE_SIZE, "ishtp:%s\n", dev_name(dev));
	return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
}

static struct device_attribute ishtp_cl_dev_attrs[] = {
	__ATTR_RO(modalias),
	__ATTR_NULL,
};

static int ishtp_cl_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	if (add_uevent_var(env, "MODALIAS=ishtp:%s", dev_name(dev)))
		return -ENOMEM;
	return 0;
}

static const struct dev_pm_ops ishtp_cl_bus_dev_pm_ops = {
	/* Suspend callbacks */
	.suspend = ishtp_cl_device_suspend,
	.resume = ishtp_cl_device_resume,
	/* Hibernate callbacks */
	.freeze = ishtp_cl_device_suspend,
	.thaw = ishtp_cl_device_resume,
	.restore = ishtp_cl_device_resume,
};

static struct bus_type ishtp_cl_bus_type = {
	.name		= "ishtp",
	.dev_attrs	= ishtp_cl_dev_attrs,
	.probe		= ishtp_cl_device_probe,
	.remove		= ishtp_cl_device_remove,
	.pm		= &ishtp_cl_bus_dev_pm_ops,
	.uevent		= ishtp_cl_uevent,
};

static void ishtp_cl_dev_release(struct device *dev)
{
	kfree(to_ishtp_cl_device(dev));
}

static const struct device_type ishtp_cl_device_type = {
	.release	= ishtp_cl_dev_release,
};

/**
 * ishtp_bus_add_device() - Function to create device on bus
 * @dev:	ishtp device
 * @uuid:	uuid of the client
 * @name:	Name of the client
 *
 * Allocate ISHTP bus client device, attach it to uuid
 * and register with ISHTP bus.
 *
 * Return: ishtp_cl_device pointer or NULL on failure
 */
static struct ishtp_cl_device *ishtp_bus_add_device(struct ishtp_device *dev,
						    uuid_le uuid, char *name)
{
	struct ishtp_cl_device *device;
	int status;
	unsigned long flags;

	spin_lock_irqsave(&dev->device_list_lock, flags);
	list_for_each_entry(device, &dev->device_list, device_link) {
		if (!strcmp(name, dev_name(&device->dev))) {
			device->fw_client = &dev->fw_clients[
				dev->fw_client_presentation_num - 1];
			spin_unlock_irqrestore(&dev->device_list_lock, flags);
			ishtp_cl_device_reset(device);
			return device;
		}
	}
	spin_unlock_irqrestore(&dev->device_list_lock, flags);

	device = kzalloc(sizeof(struct ishtp_cl_device), GFP_KERNEL);
	if (!device)
		return NULL;

	device->dev.parent = dev->devc;
	device->dev.bus = &ishtp_cl_bus_type;
	device->dev.type = &ishtp_cl_device_type;
	device->ishtp_dev = dev;

	device->fw_client =
		&dev->fw_clients[dev->fw_client_presentation_num - 1];

	dev_set_name(&device->dev, "%s", name);

	spin_lock_irqsave(&dev->device_list_lock, flags);
	list_add_tail(&device->device_link, &dev->device_list);
	spin_unlock_irqrestore(&dev->device_list_lock, flags);

	status = device_register(&device->dev);
	if (status) {
		spin_lock_irqsave(&dev->device_list_lock, flags);
		list_del(&device->device_link);
		spin_unlock_irqrestore(&dev->device_list_lock, flags);
		dev_err(dev->devc, "Failed to register ISHTP client device\n");
		kfree(device);
		return NULL;
	}

	ishtp_device_ready = true;

	return device;
}

/**
 * ishtp_bus_remove_device() - Function to relase device on bus
 * @device:	client device instance
 *
 * This is a counterpart of ishtp_bus_add_device.
 * Device is unregistered.
 * the device structure is freed in 'ishtp_cl_dev_release' function
 * Called only during error in pci driver init path.
 */
static void ishtp_bus_remove_device(struct ishtp_cl_device *device)
{
	device_unregister(&device->dev);
}

/**
 * __ishtp_cl_driver_register() - Client driver register
 * @driver:	the client driver instance
 * @owner:	Owner of this driver module
 *
 * Once a client driver is probed, it created a client
 * instance and registers with the bus.
 *
 * Return: Return value of driver_register or -ENODEV if not ready
 */
int __ishtp_cl_driver_register(struct ishtp_cl_driver *driver,
			       struct module *owner)
{
	int err;

	if (!ishtp_device_ready)
		return -ENODEV;

	driver->driver.name = driver->name;
	driver->driver.owner = owner;
	driver->driver.bus = &ishtp_cl_bus_type;

	err = driver_register(&driver->driver);
	if (err)
		return err;

	return 0;
}
EXPORT_SYMBOL(__ishtp_cl_driver_register);

/**
 * ishtp_cl_driver_unregister() - Client driver unregister
 * @driver:	the client driver instance
 *
 * Unregister client during device removal process.
 */
void ishtp_cl_driver_unregister(struct ishtp_cl_driver *driver)
{
	driver_unregister(&driver->driver);
}
EXPORT_SYMBOL(ishtp_cl_driver_unregister);

/**
 * ishtp_bus_event_work() - event work function
 * @work:	work struct pointer
 *
 * Once an event is received for a client this work
 * function is called. If the device has registered a
 * callback then the callback is called.
 */
static void ishtp_bus_event_work(struct work_struct *work)
{
	struct ishtp_cl_device *device;

	device = container_of(work, struct ishtp_cl_device, event_work);

	if (device->event_cb)
		device->event_cb(device);
}

/**
 * ishtp_cl_bus_rx_event() - schedule event work
 * @device:	client device instance
 *
 * Once an event is received for a client this schedules
 * a work function to process.
 */
void ishtp_cl_bus_rx_event(struct ishtp_cl_device *device)
{
	if (!device || !device->event_cb)
		return;

	if (device->event_cb)
		schedule_work(&device->event_work);
}

/**
 * ishtp_register_event_cb() - Register callback
 * @device:	client device instance
 * @event_cb:	Event processor for an client
 *
 * Register a callback for events, called from client driver
 *
 * Return: Return 0 or -EALREADY if already registered
 */
int ishtp_register_event_cb(struct ishtp_cl_device *device,
	void (*event_cb)(struct ishtp_cl_device *))
{
	if (device->event_cb)
		return -EALREADY;

	device->event_cb = event_cb;
	INIT_WORK(&device->event_work, ishtp_bus_event_work);

	return 0;
}
EXPORT_SYMBOL(ishtp_register_event_cb);

/**
 * ishtp_get_device() - update usage count for the device
 * @cl_device:	client device instance
 *
 * Increment the usage count. The device can't be deleted
 */
void ishtp_get_device(struct ishtp_cl_device *cl_device)
{
	cl_device->reference_count++;
}
EXPORT_SYMBOL(ishtp_get_device);

/**
 * ishtp_put_device() - decrement usage count for the device
 * @cl_device:	client device instance
 *
 * Decrement the usage count. The device can be deleted is count = 0
 */
void ishtp_put_device(struct ishtp_cl_device *cl_device)
{
	cl_device->reference_count--;
}
EXPORT_SYMBOL(ishtp_put_device);

/**
 * ishtp_bus_new_client() - Create a new client
 * @dev:	ISHTP device instance
 *
 * Once bus protocol enumerates a client, this is called
 * to add a device for the client.
 *
 * Return: 0 on success or error code on failure
 */
int ishtp_bus_new_client(struct ishtp_device *dev)
{
	int	i;
	char	*dev_name;
	struct ishtp_cl_device	*cl_device;
	uuid_le	device_uuid;

	/*
	 * For all reported clients, create an unconnected client and add its
	 * device to ISHTP bus.
	 * If appropriate driver has loaded, this will trigger its probe().
	 * Otherwise, probe() will be called when driver is loaded
	 */
	i = dev->fw_client_presentation_num - 1;
	device_uuid = dev->fw_clients[i].props.protocol_name;
	dev_name = kasprintf(GFP_KERNEL, "{%pUL}", device_uuid.b);
	if (!dev_name)
		return	-ENOMEM;

	cl_device = ishtp_bus_add_device(dev, device_uuid, dev_name);
	if (!cl_device) {
		kfree(dev_name);
		return	-ENOENT;
	}

	kfree(dev_name);

	return	0;
}

/**
 * ishtp_cl_device_bind() - bind a device
 * @cl:		ishtp client device
 *
 * Binds connected ishtp_cl to ISHTP bus device
 *
 * Return: 0 on success or fault code
 */
int ishtp_cl_device_bind(struct ishtp_cl *cl)
{
	struct ishtp_cl_device	*cl_device;
	unsigned long flags;
	int	rv;

	if (!cl->fw_client_id || cl->state != ISHTP_CL_CONNECTED)
		return	-EFAULT;

	rv = -ENOENT;
	spin_lock_irqsave(&cl->dev->device_list_lock, flags);
	list_for_each_entry(cl_device, &cl->dev->device_list,
			device_link) {
		if (cl_device->fw_client->client_id == cl->fw_client_id) {
			cl->device = cl_device;
			rv = 0;
			break;
		}
	}
	spin_unlock_irqrestore(&cl->dev->device_list_lock, flags);
	return	rv;
}

/**
 * ishtp_bus_remove_all_clients() - Remove all clients
 * @ishtp_dev:		ishtp device
 * @warm_reset:		Reset due to FW reset dure to errors or S3 suspend
 *
 * This is part of reset/remove flow. This function the main processing
 * only targets error processing, if the FW has forced reset or
 * error to remove connected clients. When warm reset the client devices are
 * not removed.
 */
void ishtp_bus_remove_all_clients(struct ishtp_device *ishtp_dev,
				  bool warm_reset)
{
	struct ishtp_cl_device	*cl_device, *n;
	struct ishtp_cl	*cl;
	unsigned long	flags;

	spin_lock_irqsave(&ishtp_dev->cl_list_lock, flags);
	list_for_each_entry(cl, &ishtp_dev->cl_list, link) {
		cl->state = ISHTP_CL_DISCONNECTED;

		/*
		 * Wake any pending process. The waiter would check dev->state
		 * and determine that it's not enabled already,
		 * and will return error to its caller
		 */
		wake_up_interruptible(&cl->wait_ctrl_res);

		/* Disband any pending read/write requests and free rb */
		ishtp_cl_flush_queues(cl);

		/* Remove all free and in_process rings, both Rx and Tx */
		ishtp_cl_free_rx_ring(cl);
		ishtp_cl_free_tx_ring(cl);

		/*
		 * Free client and ISHTP bus client device structures
		 * don't free host client because it is part of the OS fd
		 * structure
		 */
	}
	spin_unlock_irqrestore(&ishtp_dev->cl_list_lock, flags);

	/* Release DMA buffers for client messages */
	ishtp_cl_free_dma_buf(ishtp_dev);

	/* remove bus clients */
	spin_lock_irqsave(&ishtp_dev->device_list_lock, flags);
	list_for_each_entry_safe(cl_device, n, &ishtp_dev->device_list,
				 device_link) {
		if (warm_reset && cl_device->reference_count)
			continue;

		list_del(&cl_device->device_link);
		spin_unlock_irqrestore(&ishtp_dev->device_list_lock, flags);
		ishtp_bus_remove_device(cl_device);
		spin_lock_irqsave(&ishtp_dev->device_list_lock, flags);
	}
	spin_unlock_irqrestore(&ishtp_dev->device_list_lock, flags);

	/* Free all client structures */
	spin_lock_irqsave(&ishtp_dev->fw_clients_lock, flags);
	kfree(ishtp_dev->fw_clients);
	ishtp_dev->fw_clients = NULL;
	ishtp_dev->fw_clients_num = 0;
	ishtp_dev->fw_client_presentation_num = 0;
	ishtp_dev->fw_client_index = 0;
	bitmap_zero(ishtp_dev->fw_clients_map, ISHTP_CLIENTS_MAX);
	spin_unlock_irqrestore(&ishtp_dev->fw_clients_lock, flags);
}
EXPORT_SYMBOL(ishtp_bus_remove_all_clients);

/**
 * ishtp_reset_handler() - IPC reset handler
 * @dev:	ishtp device
 *
 * ISHTP Handler for IPC_RESET notification
 */
void ishtp_reset_handler(struct ishtp_device *dev)
{
	unsigned long	flags;

	/* Handle FW-initiated reset */
	dev->dev_state = ISHTP_DEV_RESETTING;

	/* Clear BH processing queue - no further HBMs */
	spin_lock_irqsave(&dev->rd_msg_spinlock, flags);
	dev->rd_msg_fifo_head = dev->rd_msg_fifo_tail = 0;
	spin_unlock_irqrestore(&dev->rd_msg_spinlock, flags);

	/* Handle ISH FW reset against upper layers */
	ishtp_bus_remove_all_clients(dev, true);
}
EXPORT_SYMBOL(ishtp_reset_handler);

/**
 * ishtp_reset_compl_handler() - Reset completion handler
 * @dev:	ishtp device
 *
 * ISHTP handler for IPC_RESET sequence completion to start
 * host message bus start protocol sequence.
 */
void ishtp_reset_compl_handler(struct ishtp_device *dev)
{
	dev->dev_state = ISHTP_DEV_INIT_CLIENTS;
	dev->hbm_state = ISHTP_HBM_START;
	ishtp_hbm_start_req(dev);
}
EXPORT_SYMBOL(ishtp_reset_compl_handler);

/**
 * ishtp_use_dma_transfer() - Function to use DMA
 *
 * This interface is used to enable usage of DMA
 *
 * Return non zero if DMA can be enabled
 */
int ishtp_use_dma_transfer(void)
{
	return ishtp_use_dma;
}

/**
 * ishtp_bus_register() - Function to register bus
 *
 * This register ishtp bus
 *
 * Return: Return output of bus_register
 */
static int  __init ishtp_bus_register(void)
{
	return bus_register(&ishtp_cl_bus_type);
}

/**
 * ishtp_bus_unregister() - Function to unregister bus
 *
 * This unregister ishtp bus
 */
static void __exit ishtp_bus_unregister(void)
{
	bus_unregister(&ishtp_cl_bus_type);
}

module_init(ishtp_bus_register);
module_exit(ishtp_bus_unregister);

MODULE_LICENSE("GPL");