aboutsummaryrefslogtreecommitdiff
path: root/drivers/hsi/hsi.c
blob: 4e2d79b793349c1d6c3b375677b2af7a87db2ccb (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
/*
 * HSI core.
 *
 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
 *
 * Contact: Carlos Chinea <carlos.chinea@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/hsi/hsi.h>
#include <linux/compiler.h>
#include <linux/rwsem.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/kobject.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "hsi_core.h"

static struct device_type hsi_ctrl = {
	.name	= "hsi_controller",
};

static struct device_type hsi_cl = {
	.name	= "hsi_client",
};

static struct device_type hsi_port = {
	.name	= "hsi_port",
};

static ssize_t modalias_show(struct device *dev,
			struct device_attribute *a __maybe_unused, char *buf)
{
	return sprintf(buf, "hsi:%s\n", dev_name(dev));
}

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

static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	if (dev->type == &hsi_cl)
		add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));

	return 0;
}

static int hsi_bus_match(struct device *dev, struct device_driver *driver)
{
	return strcmp(dev_name(dev), driver->name) == 0;
}

static struct bus_type hsi_bus_type = {
	.name		= "hsi",
	.dev_attrs	= hsi_bus_dev_attrs,
	.match		= hsi_bus_match,
	.uevent		= hsi_bus_uevent,
};

static void hsi_client_release(struct device *dev)
{
	kfree(to_hsi_client(dev));
}

static void hsi_new_client(struct hsi_port *port, struct hsi_board_info *info)
{
	struct hsi_client *cl;
	unsigned long flags;

	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
	if (!cl)
		return;
	cl->device.type = &hsi_cl;
	cl->tx_cfg = info->tx_cfg;
	cl->rx_cfg = info->rx_cfg;
	cl->device.bus = &hsi_bus_type;
	cl->device.parent = &port->device;
	cl->device.release = hsi_client_release;
	dev_set_name(&cl->device, info->name);
	cl->device.platform_data = info->platform_data;
	spin_lock_irqsave(&port->clock, flags);
	list_add_tail(&cl->link, &port->clients);
	spin_unlock_irqrestore(&port->clock, flags);
	if (info->archdata)
		cl->device.archdata = *info->archdata;
	if (device_register(&cl->device) < 0) {
		pr_err("hsi: failed to register client: %s\n", info->name);
		kfree(cl);
	}
}

static void hsi_scan_board_info(struct hsi_controller *hsi)
{
	struct hsi_cl_info *cl_info;
	struct hsi_port	*p;

	list_for_each_entry(cl_info, &hsi_board_list, list)
		if (cl_info->info.hsi_id == hsi->id) {
			p = hsi_find_port_num(hsi, cl_info->info.port);
			if (!p)
				continue;
			hsi_new_client(p, &cl_info->info);
		}
}

static int hsi_remove_client(struct device *dev, void *data __maybe_unused)
{
	struct hsi_client *cl = to_hsi_client(dev);
	struct hsi_port *port = to_hsi_port(dev->parent);
	unsigned long flags;

	spin_lock_irqsave(&port->clock, flags);
	list_del(&cl->link);
	spin_unlock_irqrestore(&port->clock, flags);
	device_unregister(dev);

	return 0;
}

static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
{
	device_for_each_child(dev, NULL, hsi_remove_client);
	device_unregister(dev);

	return 0;
}

static void hsi_controller_release(struct device *dev __maybe_unused)
{
}

static void hsi_port_release(struct device *dev __maybe_unused)
{
}

/**
 * hsi_unregister_controller - Unregister an HSI controller
 * @hsi: The HSI controller to register
 */
void hsi_unregister_controller(struct hsi_controller *hsi)
{
	device_for_each_child(&hsi->device, NULL, hsi_remove_port);
	device_unregister(&hsi->device);
}
EXPORT_SYMBOL_GPL(hsi_unregister_controller);

/**
 * hsi_register_controller - Register an HSI controller and its ports
 * @hsi: The HSI controller to register
 *
 * Returns -errno on failure, 0 on success.
 */
int hsi_register_controller(struct hsi_controller *hsi)
{
	unsigned int i;
	int err;

	hsi->device.type = &hsi_ctrl;
	hsi->device.bus = &hsi_bus_type;
	hsi->device.release = hsi_controller_release;
	err = device_register(&hsi->device);
	if (err < 0)
		return err;
	for (i = 0; i < hsi->num_ports; i++) {
		hsi->port[i].device.parent = &hsi->device;
		hsi->port[i].device.bus = &hsi_bus_type;
		hsi->port[i].device.release = hsi_port_release;
		hsi->port[i].device.type = &hsi_port;
		INIT_LIST_HEAD(&hsi->port[i].clients);
		spin_lock_init(&hsi->port[i].clock);
		err = device_register(&hsi->port[i].device);
		if (err < 0)
			goto out;
	}
	/* Populate HSI bus with HSI clients */
	hsi_scan_board_info(hsi);

	return 0;
out:
	hsi_unregister_controller(hsi);

	return err;
}
EXPORT_SYMBOL_GPL(hsi_register_controller);

/**
 * hsi_register_client_driver - Register an HSI client to the HSI bus
 * @drv: HSI client driver to register
 *
 * Returns -errno on failure, 0 on success.
 */
int hsi_register_client_driver(struct hsi_client_driver *drv)
{
	drv->driver.bus = &hsi_bus_type;

	return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(hsi_register_client_driver);

static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
{
	return 0;
}

static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
{
	return 0;
}

/**
 * hsi_alloc_controller - Allocate an HSI controller and its ports
 * @n_ports: Number of ports on the HSI controller
 * @flags: Kernel allocation flags
 *
 * Return NULL on failure or a pointer to an hsi_controller on success.
 */
struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
{
	struct hsi_controller	*hsi;
	struct hsi_port		*port;
	unsigned int		i;

	if (!n_ports)
		return NULL;

	port = kzalloc(sizeof(*port)*n_ports, flags);
	if (!port)
		return NULL;
	hsi = kzalloc(sizeof(*hsi), flags);
	if (!hsi)
		goto out;
	for (i = 0; i < n_ports; i++) {
		dev_set_name(&port[i].device, "port%d", i);
		port[i].num = i;
		port[i].async = hsi_dummy_msg;
		port[i].setup = hsi_dummy_cl;
		port[i].flush = hsi_dummy_cl;
		port[i].start_tx = hsi_dummy_cl;
		port[i].stop_tx = hsi_dummy_cl;
		port[i].release = hsi_dummy_cl;
		mutex_init(&port[i].lock);
	}
	hsi->num_ports = n_ports;
	hsi->port = port;

	return hsi;
out:
	kfree(port);

	return NULL;
}
EXPORT_SYMBOL_GPL(hsi_alloc_controller);

/**
 * hsi_free_controller - Free an HSI controller
 * @hsi: Pointer to HSI controller
 */
void hsi_free_controller(struct hsi_controller *hsi)
{
	if (!hsi)
		return;

	kfree(hsi->port);
	kfree(hsi);
}
EXPORT_SYMBOL_GPL(hsi_free_controller);

/**
 * hsi_free_msg - Free an HSI message
 * @msg: Pointer to the HSI message
 *
 * Client is responsible to free the buffers pointed by the scatterlists.
 */
void hsi_free_msg(struct hsi_msg *msg)
{
	if (!msg)
		return;
	sg_free_table(&msg->sgt);
	kfree(msg);
}
EXPORT_SYMBOL_GPL(hsi_free_msg);

/**
 * hsi_alloc_msg - Allocate an HSI message
 * @nents: Number of memory entries
 * @flags: Kernel allocation flags
 *
 * nents can be 0. This mainly makes sense for read transfer.
 * In that case, HSI drivers will call the complete callback when
 * there is data to be read without consuming it.
 *
 * Return NULL on failure or a pointer to an hsi_msg on success.
 */
struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
{
	struct hsi_msg *msg;
	int err;

	msg = kzalloc(sizeof(*msg), flags);
	if (!msg)
		return NULL;

	if (!nents)
		return msg;

	err = sg_alloc_table(&msg->sgt, nents, flags);
	if (unlikely(err)) {
		kfree(msg);
		msg = NULL;
	}

	return msg;
}
EXPORT_SYMBOL_GPL(hsi_alloc_msg);

/**
 * hsi_async - Submit an HSI transfer to the controller
 * @cl: HSI client sending the transfer
 * @msg: The HSI transfer passed to controller
 *
 * The HSI message must have the channel, ttype, complete and destructor
 * fields set beforehand. If nents > 0 then the client has to initialize
 * also the scatterlists to point to the buffers to write to or read from.
 *
 * HSI controllers relay on pre-allocated buffers from their clients and they
 * do not allocate buffers on their own.
 *
 * Once the HSI message transfer finishes, the HSI controller calls the
 * complete callback with the status and actual_len fields of the HSI message
 * updated. The complete callback can be called before returning from
 * hsi_async.
 *
 * Returns -errno on failure or 0 on success
 */
int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
{
	struct hsi_port *port = hsi_get_port(cl);

	if (!hsi_port_claimed(cl))
		return -EACCES;

	WARN_ON_ONCE(!msg->destructor || !msg->complete);
	msg->cl = cl;

	return port->async(msg);
}
EXPORT_SYMBOL_GPL(hsi_async);

/**
 * hsi_claim_port - Claim the HSI client's port
 * @cl: HSI client that wants to claim its port
 * @share: Flag to indicate if the client wants to share the port or not.
 *
 * Returns -errno on failure, 0 on success.
 */
int hsi_claim_port(struct hsi_client *cl, unsigned int share)
{
	struct hsi_port *port = hsi_get_port(cl);
	int err = 0;

	mutex_lock(&port->lock);
	if ((port->claimed) && (!port->shared || !share)) {
		err = -EBUSY;
		goto out;
	}
	if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
		err = -ENODEV;
		goto out;
	}
	port->claimed++;
	port->shared = !!share;
	cl->pclaimed = 1;
out:
	mutex_unlock(&port->lock);

	return err;
}
EXPORT_SYMBOL_GPL(hsi_claim_port);

/**
 * hsi_release_port - Release the HSI client's port
 * @cl: HSI client which previously claimed its port
 */
void hsi_release_port(struct hsi_client *cl)
{
	struct hsi_port *port = hsi_get_port(cl);

	mutex_lock(&port->lock);
	/* Allow HW driver to do some cleanup */
	port->release(cl);
	if (cl->pclaimed)
		port->claimed--;
	BUG_ON(port->claimed < 0);
	cl->pclaimed = 0;
	if (!port->claimed)
		port->shared = 0;
	module_put(to_hsi_controller(port->device.parent)->owner);
	mutex_unlock(&port->lock);
}
EXPORT_SYMBOL_GPL(hsi_release_port);

static int hsi_start_rx(struct hsi_client *cl, void *data __maybe_unused)
{
	if (cl->hsi_start_rx)
		(*cl->hsi_start_rx)(cl);

	return 0;
}

static int hsi_stop_rx(struct hsi_client *cl, void *data __maybe_unused)
{
	if (cl->hsi_stop_rx)
		(*cl->hsi_stop_rx)(cl);

	return 0;
}

static int hsi_port_for_each_client(struct hsi_port *port, void *data,
				int (*fn)(struct hsi_client *cl, void *data))
{
	struct hsi_client *cl;

	spin_lock(&port->clock);
	list_for_each_entry(cl, &port->clients, link) {
		spin_unlock(&port->clock);
		(*fn)(cl, data);
		spin_lock(&port->clock);
	}
	spin_unlock(&port->clock);

	return 0;
}

/**
 * hsi_event -Notifies clients about port events
 * @port: Port where the event occurred
 * @event: The event type
 *
 * Clients should not be concerned about wake line behavior. However, due
 * to a race condition in HSI HW protocol, clients need to be notified
 * about wake line changes, so they can implement a workaround for it.
 *
 * Events:
 * HSI_EVENT_START_RX - Incoming wake line high
 * HSI_EVENT_STOP_RX - Incoming wake line down
 */
void hsi_event(struct hsi_port *port, unsigned int event)
{
	int (*fn)(struct hsi_client *cl, void *data);

	switch (event) {
	case HSI_EVENT_START_RX:
		fn = hsi_start_rx;
		break;
	case HSI_EVENT_STOP_RX:
		fn = hsi_stop_rx;
		break;
	default:
		return;
	}
	hsi_port_for_each_client(port, NULL, fn);
}
EXPORT_SYMBOL_GPL(hsi_event);

static int __init hsi_init(void)
{
	return bus_register(&hsi_bus_type);
}
postcore_initcall(hsi_init);

static void __exit hsi_exit(void)
{
	bus_unregister(&hsi_bus_type);
}
module_exit(hsi_exit);

MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
MODULE_LICENSE("GPL v2");