xref: /openbmc/linux/drivers/hsi/hsi_core.c (revision 673aa1ed)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * HSI core.
4  *
5  * Copyright (C) 2010 Nokia Corporation. All rights reserved.
6  *
7  * Contact: Carlos Chinea <carlos.chinea@nokia.com>
8  */
9 #include <linux/hsi/hsi.h>
10 #include <linux/compiler.h>
11 #include <linux/list.h>
12 #include <linux/kobject.h>
13 #include <linux/slab.h>
14 #include <linux/string.h>
15 #include <linux/notifier.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include "hsi_core.h"
19 
modalias_show(struct device * dev,struct device_attribute * a __maybe_unused,char * buf)20 static ssize_t modalias_show(struct device *dev,
21 			struct device_attribute *a __maybe_unused, char *buf)
22 {
23 	return sprintf(buf, "hsi:%s\n", dev_name(dev));
24 }
25 static DEVICE_ATTR_RO(modalias);
26 
27 static struct attribute *hsi_bus_dev_attrs[] = {
28 	&dev_attr_modalias.attr,
29 	NULL,
30 };
31 ATTRIBUTE_GROUPS(hsi_bus_dev);
32 
hsi_bus_uevent(const struct device * dev,struct kobj_uevent_env * env)33 static int hsi_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)
34 {
35 	add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));
36 
37 	return 0;
38 }
39 
hsi_bus_match(struct device * dev,struct device_driver * driver)40 static int hsi_bus_match(struct device *dev, struct device_driver *driver)
41 {
42 	if (of_driver_match_device(dev, driver))
43 		return true;
44 
45 	if (strcmp(dev_name(dev), driver->name) == 0)
46 		return true;
47 
48 	return false;
49 }
50 
51 static struct bus_type hsi_bus_type = {
52 	.name		= "hsi",
53 	.dev_groups	= hsi_bus_dev_groups,
54 	.match		= hsi_bus_match,
55 	.uevent		= hsi_bus_uevent,
56 };
57 
hsi_client_release(struct device * dev)58 static void hsi_client_release(struct device *dev)
59 {
60 	struct hsi_client *cl = to_hsi_client(dev);
61 
62 	kfree(cl->tx_cfg.channels);
63 	kfree(cl->rx_cfg.channels);
64 	kfree(cl);
65 }
66 
hsi_new_client(struct hsi_port * port,struct hsi_board_info * info)67 struct hsi_client *hsi_new_client(struct hsi_port *port,
68 						struct hsi_board_info *info)
69 {
70 	struct hsi_client *cl;
71 	size_t size;
72 
73 	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
74 	if (!cl)
75 		goto err;
76 
77 	cl->tx_cfg = info->tx_cfg;
78 	if (cl->tx_cfg.channels) {
79 		size = cl->tx_cfg.num_channels * sizeof(*cl->tx_cfg.channels);
80 		cl->tx_cfg.channels = kmemdup(info->tx_cfg.channels, size,
81 					      GFP_KERNEL);
82 		if (!cl->tx_cfg.channels)
83 			goto err_tx;
84 	}
85 
86 	cl->rx_cfg = info->rx_cfg;
87 	if (cl->rx_cfg.channels) {
88 		size = cl->rx_cfg.num_channels * sizeof(*cl->rx_cfg.channels);
89 		cl->rx_cfg.channels = kmemdup(info->rx_cfg.channels, size,
90 					      GFP_KERNEL);
91 		if (!cl->rx_cfg.channels)
92 			goto err_rx;
93 	}
94 
95 	cl->device.bus = &hsi_bus_type;
96 	cl->device.parent = &port->device;
97 	cl->device.release = hsi_client_release;
98 	dev_set_name(&cl->device, "%s", info->name);
99 	cl->device.platform_data = info->platform_data;
100 	if (info->archdata)
101 		cl->device.archdata = *info->archdata;
102 	if (device_register(&cl->device) < 0) {
103 		pr_err("hsi: failed to register client: %s\n", info->name);
104 		put_device(&cl->device);
105 		goto err;
106 	}
107 
108 	return cl;
109 err_rx:
110 	kfree(cl->tx_cfg.channels);
111 err_tx:
112 	kfree(cl);
113 err:
114 	return NULL;
115 }
116 EXPORT_SYMBOL_GPL(hsi_new_client);
117 
hsi_scan_board_info(struct hsi_controller * hsi)118 static void hsi_scan_board_info(struct hsi_controller *hsi)
119 {
120 	struct hsi_cl_info *cl_info;
121 	struct hsi_port	*p;
122 
123 	list_for_each_entry(cl_info, &hsi_board_list, list)
124 		if (cl_info->info.hsi_id == hsi->id) {
125 			p = hsi_find_port_num(hsi, cl_info->info.port);
126 			if (!p)
127 				continue;
128 			hsi_new_client(p, &cl_info->info);
129 		}
130 }
131 
132 #ifdef CONFIG_OF
133 static struct hsi_board_info hsi_char_dev_info = {
134 	.name = "hsi_char",
135 };
136 
hsi_of_property_parse_mode(struct device_node * client,char * name,unsigned int * result)137 static int hsi_of_property_parse_mode(struct device_node *client, char *name,
138 				      unsigned int *result)
139 {
140 	const char *mode;
141 	int err;
142 
143 	err = of_property_read_string(client, name, &mode);
144 	if (err < 0)
145 		return err;
146 
147 	if (strcmp(mode, "stream") == 0)
148 		*result = HSI_MODE_STREAM;
149 	else if (strcmp(mode, "frame") == 0)
150 		*result = HSI_MODE_FRAME;
151 	else
152 		return -EINVAL;
153 
154 	return 0;
155 }
156 
hsi_of_property_parse_flow(struct device_node * client,char * name,unsigned int * result)157 static int hsi_of_property_parse_flow(struct device_node *client, char *name,
158 				      unsigned int *result)
159 {
160 	const char *flow;
161 	int err;
162 
163 	err = of_property_read_string(client, name, &flow);
164 	if (err < 0)
165 		return err;
166 
167 	if (strcmp(flow, "synchronized") == 0)
168 		*result = HSI_FLOW_SYNC;
169 	else if (strcmp(flow, "pipeline") == 0)
170 		*result = HSI_FLOW_PIPE;
171 	else
172 		return -EINVAL;
173 
174 	return 0;
175 }
176 
hsi_of_property_parse_arb_mode(struct device_node * client,char * name,unsigned int * result)177 static int hsi_of_property_parse_arb_mode(struct device_node *client,
178 					  char *name, unsigned int *result)
179 {
180 	const char *arb_mode;
181 	int err;
182 
183 	err = of_property_read_string(client, name, &arb_mode);
184 	if (err < 0)
185 		return err;
186 
187 	if (strcmp(arb_mode, "round-robin") == 0)
188 		*result = HSI_ARB_RR;
189 	else if (strcmp(arb_mode, "priority") == 0)
190 		*result = HSI_ARB_PRIO;
191 	else
192 		return -EINVAL;
193 
194 	return 0;
195 }
196 
hsi_add_client_from_dt(struct hsi_port * port,struct device_node * client)197 static void hsi_add_client_from_dt(struct hsi_port *port,
198 						struct device_node *client)
199 {
200 	struct hsi_client *cl;
201 	struct hsi_channel channel;
202 	struct property *prop;
203 	char name[32];
204 	int length, cells, err, i, max_chan, mode;
205 
206 	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
207 	if (!cl)
208 		return;
209 
210 	err = of_alias_from_compatible(client, name, sizeof(name));
211 	if (err)
212 		goto err;
213 
214 	err = hsi_of_property_parse_mode(client, "hsi-mode", &mode);
215 	if (err) {
216 		err = hsi_of_property_parse_mode(client, "hsi-rx-mode",
217 						 &cl->rx_cfg.mode);
218 		if (err)
219 			goto err;
220 
221 		err = hsi_of_property_parse_mode(client, "hsi-tx-mode",
222 						 &cl->tx_cfg.mode);
223 		if (err)
224 			goto err;
225 	} else {
226 		cl->rx_cfg.mode = mode;
227 		cl->tx_cfg.mode = mode;
228 	}
229 
230 	err = of_property_read_u32(client, "hsi-speed-kbps",
231 				   &cl->tx_cfg.speed);
232 	if (err)
233 		goto err;
234 	cl->rx_cfg.speed = cl->tx_cfg.speed;
235 
236 	err = hsi_of_property_parse_flow(client, "hsi-flow",
237 					 &cl->rx_cfg.flow);
238 	if (err)
239 		goto err;
240 
241 	err = hsi_of_property_parse_arb_mode(client, "hsi-arb-mode",
242 					     &cl->rx_cfg.arb_mode);
243 	if (err)
244 		goto err;
245 
246 	prop = of_find_property(client, "hsi-channel-ids", &length);
247 	if (!prop) {
248 		err = -EINVAL;
249 		goto err;
250 	}
251 
252 	cells = length / sizeof(u32);
253 
254 	cl->rx_cfg.num_channels = cells;
255 	cl->tx_cfg.num_channels = cells;
256 	cl->rx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
257 	if (!cl->rx_cfg.channels) {
258 		err = -ENOMEM;
259 		goto err;
260 	}
261 
262 	cl->tx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
263 	if (!cl->tx_cfg.channels) {
264 		err = -ENOMEM;
265 		goto err2;
266 	}
267 
268 	max_chan = 0;
269 	for (i = 0; i < cells; i++) {
270 		err = of_property_read_u32_index(client, "hsi-channel-ids", i,
271 						 &channel.id);
272 		if (err)
273 			goto err3;
274 
275 		err = of_property_read_string_index(client, "hsi-channel-names",
276 						    i, &channel.name);
277 		if (err)
278 			channel.name = NULL;
279 
280 		if (channel.id > max_chan)
281 			max_chan = channel.id;
282 
283 		cl->rx_cfg.channels[i] = channel;
284 		cl->tx_cfg.channels[i] = channel;
285 	}
286 
287 	cl->rx_cfg.num_hw_channels = max_chan + 1;
288 	cl->tx_cfg.num_hw_channels = max_chan + 1;
289 
290 	cl->device.bus = &hsi_bus_type;
291 	cl->device.parent = &port->device;
292 	cl->device.release = hsi_client_release;
293 	cl->device.of_node = client;
294 
295 	dev_set_name(&cl->device, "%s", name);
296 	if (device_register(&cl->device) < 0) {
297 		pr_err("hsi: failed to register client: %s\n", name);
298 		put_device(&cl->device);
299 	}
300 
301 	return;
302 
303 err3:
304 	kfree(cl->tx_cfg.channels);
305 err2:
306 	kfree(cl->rx_cfg.channels);
307 err:
308 	kfree(cl);
309 	pr_err("hsi client: missing or incorrect of property: err=%d\n", err);
310 }
311 
hsi_add_clients_from_dt(struct hsi_port * port,struct device_node * clients)312 void hsi_add_clients_from_dt(struct hsi_port *port, struct device_node *clients)
313 {
314 	struct device_node *child;
315 
316 	/* register hsi-char device */
317 	hsi_new_client(port, &hsi_char_dev_info);
318 
319 	for_each_available_child_of_node(clients, child)
320 		hsi_add_client_from_dt(port, child);
321 }
322 EXPORT_SYMBOL_GPL(hsi_add_clients_from_dt);
323 #endif
324 
hsi_remove_client(struct device * dev,void * data __maybe_unused)325 int hsi_remove_client(struct device *dev, void *data __maybe_unused)
326 {
327 	device_unregister(dev);
328 
329 	return 0;
330 }
331 EXPORT_SYMBOL_GPL(hsi_remove_client);
332 
hsi_remove_port(struct device * dev,void * data __maybe_unused)333 static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
334 {
335 	device_for_each_child(dev, NULL, hsi_remove_client);
336 	device_unregister(dev);
337 
338 	return 0;
339 }
340 
hsi_controller_release(struct device * dev)341 static void hsi_controller_release(struct device *dev)
342 {
343 	struct hsi_controller *hsi = to_hsi_controller(dev);
344 
345 	kfree(hsi->port);
346 	kfree(hsi);
347 }
348 
hsi_port_release(struct device * dev)349 static void hsi_port_release(struct device *dev)
350 {
351 	kfree(to_hsi_port(dev));
352 }
353 
354 /**
355  * hsi_port_unregister_clients - Unregister an HSI port
356  * @port: The HSI port to unregister
357  */
hsi_port_unregister_clients(struct hsi_port * port)358 void hsi_port_unregister_clients(struct hsi_port *port)
359 {
360 	device_for_each_child(&port->device, NULL, hsi_remove_client);
361 }
362 EXPORT_SYMBOL_GPL(hsi_port_unregister_clients);
363 
364 /**
365  * hsi_unregister_controller - Unregister an HSI controller
366  * @hsi: The HSI controller to register
367  */
hsi_unregister_controller(struct hsi_controller * hsi)368 void hsi_unregister_controller(struct hsi_controller *hsi)
369 {
370 	device_for_each_child(&hsi->device, NULL, hsi_remove_port);
371 	device_unregister(&hsi->device);
372 }
373 EXPORT_SYMBOL_GPL(hsi_unregister_controller);
374 
375 /**
376  * hsi_register_controller - Register an HSI controller and its ports
377  * @hsi: The HSI controller to register
378  *
379  * Returns -errno on failure, 0 on success.
380  */
hsi_register_controller(struct hsi_controller * hsi)381 int hsi_register_controller(struct hsi_controller *hsi)
382 {
383 	unsigned int i;
384 	int err;
385 
386 	err = device_add(&hsi->device);
387 	if (err < 0)
388 		return err;
389 	for (i = 0; i < hsi->num_ports; i++) {
390 		hsi->port[i]->device.parent = &hsi->device;
391 		err = device_add(&hsi->port[i]->device);
392 		if (err < 0)
393 			goto out;
394 	}
395 	/* Populate HSI bus with HSI clients */
396 	hsi_scan_board_info(hsi);
397 
398 	return 0;
399 out:
400 	while (i-- > 0)
401 		device_del(&hsi->port[i]->device);
402 	device_del(&hsi->device);
403 
404 	return err;
405 }
406 EXPORT_SYMBOL_GPL(hsi_register_controller);
407 
408 /**
409  * hsi_register_client_driver - Register an HSI client to the HSI bus
410  * @drv: HSI client driver to register
411  *
412  * Returns -errno on failure, 0 on success.
413  */
hsi_register_client_driver(struct hsi_client_driver * drv)414 int hsi_register_client_driver(struct hsi_client_driver *drv)
415 {
416 	drv->driver.bus = &hsi_bus_type;
417 
418 	return driver_register(&drv->driver);
419 }
420 EXPORT_SYMBOL_GPL(hsi_register_client_driver);
421 
hsi_dummy_msg(struct hsi_msg * msg __maybe_unused)422 static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
423 {
424 	return 0;
425 }
426 
hsi_dummy_cl(struct hsi_client * cl __maybe_unused)427 static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
428 {
429 	return 0;
430 }
431 
432 /**
433  * hsi_put_controller - Free an HSI controller
434  *
435  * @hsi: Pointer to the HSI controller to freed
436  *
437  * HSI controller drivers should only use this function if they need
438  * to free their allocated hsi_controller structures before a successful
439  * call to hsi_register_controller. Other use is not allowed.
440  */
hsi_put_controller(struct hsi_controller * hsi)441 void hsi_put_controller(struct hsi_controller *hsi)
442 {
443 	unsigned int i;
444 
445 	if (!hsi)
446 		return;
447 
448 	for (i = 0; i < hsi->num_ports; i++)
449 		if (hsi->port && hsi->port[i])
450 			put_device(&hsi->port[i]->device);
451 	put_device(&hsi->device);
452 }
453 EXPORT_SYMBOL_GPL(hsi_put_controller);
454 
455 /**
456  * hsi_alloc_controller - Allocate an HSI controller and its ports
457  * @n_ports: Number of ports on the HSI controller
458  * @flags: Kernel allocation flags
459  *
460  * Return NULL on failure or a pointer to an hsi_controller on success.
461  */
hsi_alloc_controller(unsigned int n_ports,gfp_t flags)462 struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
463 {
464 	struct hsi_controller	*hsi;
465 	struct hsi_port		**port;
466 	unsigned int		i;
467 
468 	if (!n_ports)
469 		return NULL;
470 
471 	hsi = kzalloc(sizeof(*hsi), flags);
472 	if (!hsi)
473 		return NULL;
474 	port = kcalloc(n_ports, sizeof(*port), flags);
475 	if (!port) {
476 		kfree(hsi);
477 		return NULL;
478 	}
479 	hsi->num_ports = n_ports;
480 	hsi->port = port;
481 	hsi->device.release = hsi_controller_release;
482 	device_initialize(&hsi->device);
483 
484 	for (i = 0; i < n_ports; i++) {
485 		port[i] = kzalloc(sizeof(**port), flags);
486 		if (port[i] == NULL)
487 			goto out;
488 		port[i]->num = i;
489 		port[i]->async = hsi_dummy_msg;
490 		port[i]->setup = hsi_dummy_cl;
491 		port[i]->flush = hsi_dummy_cl;
492 		port[i]->start_tx = hsi_dummy_cl;
493 		port[i]->stop_tx = hsi_dummy_cl;
494 		port[i]->release = hsi_dummy_cl;
495 		mutex_init(&port[i]->lock);
496 		BLOCKING_INIT_NOTIFIER_HEAD(&port[i]->n_head);
497 		dev_set_name(&port[i]->device, "port%d", i);
498 		hsi->port[i]->device.release = hsi_port_release;
499 		device_initialize(&hsi->port[i]->device);
500 	}
501 
502 	return hsi;
503 out:
504 	hsi_put_controller(hsi);
505 
506 	return NULL;
507 }
508 EXPORT_SYMBOL_GPL(hsi_alloc_controller);
509 
510 /**
511  * hsi_free_msg - Free an HSI message
512  * @msg: Pointer to the HSI message
513  *
514  * Client is responsible to free the buffers pointed by the scatterlists.
515  */
hsi_free_msg(struct hsi_msg * msg)516 void hsi_free_msg(struct hsi_msg *msg)
517 {
518 	if (!msg)
519 		return;
520 	sg_free_table(&msg->sgt);
521 	kfree(msg);
522 }
523 EXPORT_SYMBOL_GPL(hsi_free_msg);
524 
525 /**
526  * hsi_alloc_msg - Allocate an HSI message
527  * @nents: Number of memory entries
528  * @flags: Kernel allocation flags
529  *
530  * nents can be 0. This mainly makes sense for read transfer.
531  * In that case, HSI drivers will call the complete callback when
532  * there is data to be read without consuming it.
533  *
534  * Return NULL on failure or a pointer to an hsi_msg on success.
535  */
hsi_alloc_msg(unsigned int nents,gfp_t flags)536 struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
537 {
538 	struct hsi_msg *msg;
539 	int err;
540 
541 	msg = kzalloc(sizeof(*msg), flags);
542 	if (!msg)
543 		return NULL;
544 
545 	if (!nents)
546 		return msg;
547 
548 	err = sg_alloc_table(&msg->sgt, nents, flags);
549 	if (unlikely(err)) {
550 		kfree(msg);
551 		msg = NULL;
552 	}
553 
554 	return msg;
555 }
556 EXPORT_SYMBOL_GPL(hsi_alloc_msg);
557 
558 /**
559  * hsi_async - Submit an HSI transfer to the controller
560  * @cl: HSI client sending the transfer
561  * @msg: The HSI transfer passed to controller
562  *
563  * The HSI message must have the channel, ttype, complete and destructor
564  * fields set beforehand. If nents > 0 then the client has to initialize
565  * also the scatterlists to point to the buffers to write to or read from.
566  *
567  * HSI controllers relay on pre-allocated buffers from their clients and they
568  * do not allocate buffers on their own.
569  *
570  * Once the HSI message transfer finishes, the HSI controller calls the
571  * complete callback with the status and actual_len fields of the HSI message
572  * updated. The complete callback can be called before returning from
573  * hsi_async.
574  *
575  * Returns -errno on failure or 0 on success
576  */
hsi_async(struct hsi_client * cl,struct hsi_msg * msg)577 int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
578 {
579 	struct hsi_port *port = hsi_get_port(cl);
580 
581 	if (!hsi_port_claimed(cl))
582 		return -EACCES;
583 
584 	WARN_ON_ONCE(!msg->destructor || !msg->complete);
585 	msg->cl = cl;
586 
587 	return port->async(msg);
588 }
589 EXPORT_SYMBOL_GPL(hsi_async);
590 
591 /**
592  * hsi_claim_port - Claim the HSI client's port
593  * @cl: HSI client that wants to claim its port
594  * @share: Flag to indicate if the client wants to share the port or not.
595  *
596  * Returns -errno on failure, 0 on success.
597  */
hsi_claim_port(struct hsi_client * cl,unsigned int share)598 int hsi_claim_port(struct hsi_client *cl, unsigned int share)
599 {
600 	struct hsi_port *port = hsi_get_port(cl);
601 	int err = 0;
602 
603 	mutex_lock(&port->lock);
604 	if ((port->claimed) && (!port->shared || !share)) {
605 		err = -EBUSY;
606 		goto out;
607 	}
608 	if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
609 		err = -ENODEV;
610 		goto out;
611 	}
612 	port->claimed++;
613 	port->shared = !!share;
614 	cl->pclaimed = 1;
615 out:
616 	mutex_unlock(&port->lock);
617 
618 	return err;
619 }
620 EXPORT_SYMBOL_GPL(hsi_claim_port);
621 
622 /**
623  * hsi_release_port - Release the HSI client's port
624  * @cl: HSI client which previously claimed its port
625  */
hsi_release_port(struct hsi_client * cl)626 void hsi_release_port(struct hsi_client *cl)
627 {
628 	struct hsi_port *port = hsi_get_port(cl);
629 
630 	mutex_lock(&port->lock);
631 	/* Allow HW driver to do some cleanup */
632 	port->release(cl);
633 	if (cl->pclaimed)
634 		port->claimed--;
635 	BUG_ON(port->claimed < 0);
636 	cl->pclaimed = 0;
637 	if (!port->claimed)
638 		port->shared = 0;
639 	module_put(to_hsi_controller(port->device.parent)->owner);
640 	mutex_unlock(&port->lock);
641 }
642 EXPORT_SYMBOL_GPL(hsi_release_port);
643 
hsi_event_notifier_call(struct notifier_block * nb,unsigned long event,void * data __maybe_unused)644 static int hsi_event_notifier_call(struct notifier_block *nb,
645 				unsigned long event, void *data __maybe_unused)
646 {
647 	struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
648 
649 	(*cl->ehandler)(cl, event);
650 
651 	return 0;
652 }
653 
654 /**
655  * hsi_register_port_event - Register a client to receive port events
656  * @cl: HSI client that wants to receive port events
657  * @handler: Event handler callback
658  *
659  * Clients should register a callback to be able to receive
660  * events from the ports. Registration should happen after
661  * claiming the port.
662  * The handler can be called in interrupt context.
663  *
664  * Returns -errno on error, or 0 on success.
665  */
hsi_register_port_event(struct hsi_client * cl,void (* handler)(struct hsi_client *,unsigned long))666 int hsi_register_port_event(struct hsi_client *cl,
667 			void (*handler)(struct hsi_client *, unsigned long))
668 {
669 	struct hsi_port *port = hsi_get_port(cl);
670 
671 	if (!handler || cl->ehandler)
672 		return -EINVAL;
673 	if (!hsi_port_claimed(cl))
674 		return -EACCES;
675 	cl->ehandler = handler;
676 	cl->nb.notifier_call = hsi_event_notifier_call;
677 
678 	return blocking_notifier_chain_register(&port->n_head, &cl->nb);
679 }
680 EXPORT_SYMBOL_GPL(hsi_register_port_event);
681 
682 /**
683  * hsi_unregister_port_event - Stop receiving port events for a client
684  * @cl: HSI client that wants to stop receiving port events
685  *
686  * Clients should call this function before releasing their associated
687  * port.
688  *
689  * Returns -errno on error, or 0 on success.
690  */
hsi_unregister_port_event(struct hsi_client * cl)691 int hsi_unregister_port_event(struct hsi_client *cl)
692 {
693 	struct hsi_port *port = hsi_get_port(cl);
694 	int err;
695 
696 	WARN_ON(!hsi_port_claimed(cl));
697 
698 	err = blocking_notifier_chain_unregister(&port->n_head, &cl->nb);
699 	if (!err)
700 		cl->ehandler = NULL;
701 
702 	return err;
703 }
704 EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
705 
706 /**
707  * hsi_event - Notifies clients about port events
708  * @port: Port where the event occurred
709  * @event: The event type
710  *
711  * Clients should not be concerned about wake line behavior. However, due
712  * to a race condition in HSI HW protocol, clients need to be notified
713  * about wake line changes, so they can implement a workaround for it.
714  *
715  * Events:
716  * HSI_EVENT_START_RX - Incoming wake line high
717  * HSI_EVENT_STOP_RX - Incoming wake line down
718  *
719  * Returns -errno on error, or 0 on success.
720  */
hsi_event(struct hsi_port * port,unsigned long event)721 int hsi_event(struct hsi_port *port, unsigned long event)
722 {
723 	return blocking_notifier_call_chain(&port->n_head, event, NULL);
724 }
725 EXPORT_SYMBOL_GPL(hsi_event);
726 
727 /**
728  * hsi_get_channel_id_by_name - acquire channel id by channel name
729  * @cl: HSI client, which uses the channel
730  * @name: name the channel is known under
731  *
732  * Clients can call this function to get the hsi channel ids similar to
733  * requesting IRQs or GPIOs by name. This function assumes the same
734  * channel configuration is used for RX and TX.
735  *
736  * Returns -errno on error or channel id on success.
737  */
hsi_get_channel_id_by_name(struct hsi_client * cl,char * name)738 int hsi_get_channel_id_by_name(struct hsi_client *cl, char *name)
739 {
740 	int i;
741 
742 	if (!cl->rx_cfg.channels)
743 		return -ENOENT;
744 
745 	for (i = 0; i < cl->rx_cfg.num_channels; i++)
746 		if (!strcmp(cl->rx_cfg.channels[i].name, name))
747 			return cl->rx_cfg.channels[i].id;
748 
749 	return -ENXIO;
750 }
751 EXPORT_SYMBOL_GPL(hsi_get_channel_id_by_name);
752 
hsi_init(void)753 static int __init hsi_init(void)
754 {
755 	return bus_register(&hsi_bus_type);
756 }
757 postcore_initcall(hsi_init);
758 
hsi_exit(void)759 static void __exit hsi_exit(void)
760 {
761 	bus_unregister(&hsi_bus_type);
762 }
763 module_exit(hsi_exit);
764 
765 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
766 MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
767 MODULE_LICENSE("GPL v2");
768