1/*
2 * HSI core.
3 *
4 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
5 *
6 * Contact: Carlos Chinea <carlos.chinea@nokia.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * version 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA
21 */
22#include <linux/hsi/hsi.h>
23#include <linux/compiler.h>
24#include <linux/list.h>
25#include <linux/kobject.h>
26#include <linux/slab.h>
27#include <linux/string.h>
28#include <linux/notifier.h>
29#include <linux/of.h>
30#include <linux/of_device.h>
31#include "hsi_core.h"
32
33static ssize_t modalias_show(struct device *dev,
34			struct device_attribute *a __maybe_unused, char *buf)
35{
36	return sprintf(buf, "hsi:%s\n", dev_name(dev));
37}
38static DEVICE_ATTR_RO(modalias);
39
40static struct attribute *hsi_bus_dev_attrs[] = {
41	&dev_attr_modalias.attr,
42	NULL,
43};
44ATTRIBUTE_GROUPS(hsi_bus_dev);
45
46static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
47{
48	add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));
49
50	return 0;
51}
52
53static int hsi_bus_match(struct device *dev, struct device_driver *driver)
54{
55	if (of_driver_match_device(dev, driver))
56		return true;
57
58	if (strcmp(dev_name(dev), driver->name) == 0)
59		return true;
60
61	return false;
62}
63
64static struct bus_type hsi_bus_type = {
65	.name		= "hsi",
66	.dev_groups	= hsi_bus_dev_groups,
67	.match		= hsi_bus_match,
68	.uevent		= hsi_bus_uevent,
69};
70
71static void hsi_client_release(struct device *dev)
72{
73	struct hsi_client *cl = to_hsi_client(dev);
74
75	kfree(cl->tx_cfg.channels);
76	kfree(cl->rx_cfg.channels);
77	kfree(cl);
78}
79
80struct hsi_client *hsi_new_client(struct hsi_port *port,
81						struct hsi_board_info *info)
82{
83	struct hsi_client *cl;
84	size_t size;
85
86	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
87	if (!cl)
88		return NULL;
89
90	cl->tx_cfg = info->tx_cfg;
91	if (cl->tx_cfg.channels) {
92		size = cl->tx_cfg.num_channels * sizeof(*cl->tx_cfg.channels);
93		cl->tx_cfg.channels = kzalloc(size , GFP_KERNEL);
94		memcpy(cl->tx_cfg.channels, info->tx_cfg.channels, size);
95	}
96
97	cl->rx_cfg = info->rx_cfg;
98	if (cl->rx_cfg.channels) {
99		size = cl->rx_cfg.num_channels * sizeof(*cl->rx_cfg.channels);
100		cl->rx_cfg.channels = kzalloc(size , GFP_KERNEL);
101		memcpy(cl->rx_cfg.channels, info->rx_cfg.channels, size);
102	}
103
104	cl->device.bus = &hsi_bus_type;
105	cl->device.parent = &port->device;
106	cl->device.release = hsi_client_release;
107	dev_set_name(&cl->device, "%s", info->name);
108	cl->device.platform_data = info->platform_data;
109	if (info->archdata)
110		cl->device.archdata = *info->archdata;
111	if (device_register(&cl->device) < 0) {
112		pr_err("hsi: failed to register client: %s\n", info->name);
113		put_device(&cl->device);
114	}
115
116	return cl;
117}
118EXPORT_SYMBOL_GPL(hsi_new_client);
119
120static void hsi_scan_board_info(struct hsi_controller *hsi)
121{
122	struct hsi_cl_info *cl_info;
123	struct hsi_port	*p;
124
125	list_for_each_entry(cl_info, &hsi_board_list, list)
126		if (cl_info->info.hsi_id == hsi->id) {
127			p = hsi_find_port_num(hsi, cl_info->info.port);
128			if (!p)
129				continue;
130			hsi_new_client(p, &cl_info->info);
131		}
132}
133
134#ifdef CONFIG_OF
135static struct hsi_board_info hsi_char_dev_info = {
136	.name = "hsi_char",
137};
138
139static int hsi_of_property_parse_mode(struct device_node *client, char *name,
140				      unsigned int *result)
141{
142	const char *mode;
143	int err;
144
145	err = of_property_read_string(client, name, &mode);
146	if (err < 0)
147		return err;
148
149	if (strcmp(mode, "stream") == 0)
150		*result = HSI_MODE_STREAM;
151	else if (strcmp(mode, "frame") == 0)
152		*result = HSI_MODE_FRAME;
153	else
154		return -EINVAL;
155
156	return 0;
157}
158
159static int hsi_of_property_parse_flow(struct device_node *client, char *name,
160				      unsigned int *result)
161{
162	const char *flow;
163	int err;
164
165	err = of_property_read_string(client, name, &flow);
166	if (err < 0)
167		return err;
168
169	if (strcmp(flow, "synchronized") == 0)
170		*result = HSI_FLOW_SYNC;
171	else if (strcmp(flow, "pipeline") == 0)
172		*result = HSI_FLOW_PIPE;
173	else
174		return -EINVAL;
175
176	return 0;
177}
178
179static int hsi_of_property_parse_arb_mode(struct device_node *client,
180					  char *name, unsigned int *result)
181{
182	const char *arb_mode;
183	int err;
184
185	err = of_property_read_string(client, name, &arb_mode);
186	if (err < 0)
187		return err;
188
189	if (strcmp(arb_mode, "round-robin") == 0)
190		*result = HSI_ARB_RR;
191	else if (strcmp(arb_mode, "priority") == 0)
192		*result = HSI_ARB_PRIO;
193	else
194		return -EINVAL;
195
196	return 0;
197}
198
199static void hsi_add_client_from_dt(struct hsi_port *port,
200						struct device_node *client)
201{
202	struct hsi_client *cl;
203	struct hsi_channel channel;
204	struct property *prop;
205	char name[32];
206	int length, cells, err, i, max_chan, mode;
207
208	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
209	if (!cl)
210		return;
211
212	err = of_modalias_node(client, name, sizeof(name));
213	if (err)
214		goto err;
215
216	dev_set_name(&cl->device, "%s", name);
217
218	err = hsi_of_property_parse_mode(client, "hsi-mode", &mode);
219	if (err) {
220		err = hsi_of_property_parse_mode(client, "hsi-rx-mode",
221						 &cl->rx_cfg.mode);
222		if (err)
223			goto err;
224
225		err = hsi_of_property_parse_mode(client, "hsi-tx-mode",
226						 &cl->tx_cfg.mode);
227		if (err)
228			goto err;
229	} else {
230		cl->rx_cfg.mode = mode;
231		cl->tx_cfg.mode = mode;
232	}
233
234	err = of_property_read_u32(client, "hsi-speed-kbps",
235				   &cl->tx_cfg.speed);
236	if (err)
237		goto err;
238	cl->rx_cfg.speed = cl->tx_cfg.speed;
239
240	err = hsi_of_property_parse_flow(client, "hsi-flow",
241					 &cl->rx_cfg.flow);
242	if (err)
243		goto err;
244
245	err = hsi_of_property_parse_arb_mode(client, "hsi-arb-mode",
246					     &cl->rx_cfg.arb_mode);
247	if (err)
248		goto err;
249
250	prop = of_find_property(client, "hsi-channel-ids", &length);
251	if (!prop) {
252		err = -EINVAL;
253		goto err;
254	}
255
256	cells = length / sizeof(u32);
257
258	cl->rx_cfg.num_channels = cells;
259	cl->tx_cfg.num_channels = cells;
260
261	cl->rx_cfg.channels = kzalloc(cells * sizeof(channel), GFP_KERNEL);
262	if (!cl->rx_cfg.channels) {
263		err = -ENOMEM;
264		goto err;
265	}
266
267	cl->tx_cfg.channels = kzalloc(cells * sizeof(channel), GFP_KERNEL);
268	if (!cl->tx_cfg.channels) {
269		err = -ENOMEM;
270		goto err2;
271	}
272
273	max_chan = 0;
274	for (i = 0; i < cells; i++) {
275		err = of_property_read_u32_index(client, "hsi-channel-ids", i,
276						 &channel.id);
277		if (err)
278			goto err3;
279
280		err = of_property_read_string_index(client, "hsi-channel-names",
281						    i, &channel.name);
282		if (err)
283			channel.name = NULL;
284
285		if (channel.id > max_chan)
286			max_chan = channel.id;
287
288		cl->rx_cfg.channels[i] = channel;
289		cl->tx_cfg.channels[i] = channel;
290	}
291
292	cl->rx_cfg.num_hw_channels = max_chan + 1;
293	cl->tx_cfg.num_hw_channels = max_chan + 1;
294
295	cl->device.bus = &hsi_bus_type;
296	cl->device.parent = &port->device;
297	cl->device.release = hsi_client_release;
298	cl->device.of_node = client;
299
300	if (device_register(&cl->device) < 0) {
301		pr_err("hsi: failed to register client: %s\n", name);
302		put_device(&cl->device);
303		goto err3;
304	}
305
306	return;
307
308err3:
309	kfree(cl->tx_cfg.channels);
310err2:
311	kfree(cl->rx_cfg.channels);
312err:
313	kfree(cl);
314	pr_err("hsi client: missing or incorrect of property: err=%d\n", err);
315}
316
317void hsi_add_clients_from_dt(struct hsi_port *port, struct device_node *clients)
318{
319	struct device_node *child;
320
321	/* register hsi-char device */
322	hsi_new_client(port, &hsi_char_dev_info);
323
324	for_each_available_child_of_node(clients, child)
325		hsi_add_client_from_dt(port, child);
326}
327EXPORT_SYMBOL_GPL(hsi_add_clients_from_dt);
328#endif
329
330int hsi_remove_client(struct device *dev, void *data __maybe_unused)
331{
332	device_unregister(dev);
333
334	return 0;
335}
336EXPORT_SYMBOL_GPL(hsi_remove_client);
337
338static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
339{
340	device_for_each_child(dev, NULL, hsi_remove_client);
341	device_unregister(dev);
342
343	return 0;
344}
345
346static void hsi_controller_release(struct device *dev)
347{
348	struct hsi_controller *hsi = to_hsi_controller(dev);
349
350	kfree(hsi->port);
351	kfree(hsi);
352}
353
354static void hsi_port_release(struct device *dev)
355{
356	kfree(to_hsi_port(dev));
357}
358
359/**
360 * hsi_unregister_port - Unregister an HSI port
361 * @port: The HSI port to unregister
362 */
363void hsi_port_unregister_clients(struct hsi_port *port)
364{
365	device_for_each_child(&port->device, NULL, hsi_remove_client);
366}
367EXPORT_SYMBOL_GPL(hsi_port_unregister_clients);
368
369/**
370 * hsi_unregister_controller - Unregister an HSI controller
371 * @hsi: The HSI controller to register
372 */
373void hsi_unregister_controller(struct hsi_controller *hsi)
374{
375	device_for_each_child(&hsi->device, NULL, hsi_remove_port);
376	device_unregister(&hsi->device);
377}
378EXPORT_SYMBOL_GPL(hsi_unregister_controller);
379
380/**
381 * hsi_register_controller - Register an HSI controller and its ports
382 * @hsi: The HSI controller to register
383 *
384 * Returns -errno on failure, 0 on success.
385 */
386int hsi_register_controller(struct hsi_controller *hsi)
387{
388	unsigned int i;
389	int err;
390
391	err = device_add(&hsi->device);
392	if (err < 0)
393		return err;
394	for (i = 0; i < hsi->num_ports; i++) {
395		hsi->port[i]->device.parent = &hsi->device;
396		err = device_add(&hsi->port[i]->device);
397		if (err < 0)
398			goto out;
399	}
400	/* Populate HSI bus with HSI clients */
401	hsi_scan_board_info(hsi);
402
403	return 0;
404out:
405	while (i-- > 0)
406		device_del(&hsi->port[i]->device);
407	device_del(&hsi->device);
408
409	return err;
410}
411EXPORT_SYMBOL_GPL(hsi_register_controller);
412
413/**
414 * hsi_register_client_driver - Register an HSI client to the HSI bus
415 * @drv: HSI client driver to register
416 *
417 * Returns -errno on failure, 0 on success.
418 */
419int hsi_register_client_driver(struct hsi_client_driver *drv)
420{
421	drv->driver.bus = &hsi_bus_type;
422
423	return driver_register(&drv->driver);
424}
425EXPORT_SYMBOL_GPL(hsi_register_client_driver);
426
427static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
428{
429	return 0;
430}
431
432static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
433{
434	return 0;
435}
436
437/**
438 * hsi_put_controller - Free an HSI controller
439 *
440 * @hsi: Pointer to the HSI controller to freed
441 *
442 * HSI controller drivers should only use this function if they need
443 * to free their allocated hsi_controller structures before a successful
444 * call to hsi_register_controller. Other use is not allowed.
445 */
446void hsi_put_controller(struct hsi_controller *hsi)
447{
448	unsigned int i;
449
450	if (!hsi)
451		return;
452
453	for (i = 0; i < hsi->num_ports; i++)
454		if (hsi->port && hsi->port[i])
455			put_device(&hsi->port[i]->device);
456	put_device(&hsi->device);
457}
458EXPORT_SYMBOL_GPL(hsi_put_controller);
459
460/**
461 * hsi_alloc_controller - Allocate an HSI controller and its ports
462 * @n_ports: Number of ports on the HSI controller
463 * @flags: Kernel allocation flags
464 *
465 * Return NULL on failure or a pointer to an hsi_controller on success.
466 */
467struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
468{
469	struct hsi_controller	*hsi;
470	struct hsi_port		**port;
471	unsigned int		i;
472
473	if (!n_ports)
474		return NULL;
475
476	hsi = kzalloc(sizeof(*hsi), flags);
477	if (!hsi)
478		return NULL;
479	port = kzalloc(sizeof(*port)*n_ports, flags);
480	if (!port) {
481		kfree(hsi);
482		return NULL;
483	}
484	hsi->num_ports = n_ports;
485	hsi->port = port;
486	hsi->device.release = hsi_controller_release;
487	device_initialize(&hsi->device);
488
489	for (i = 0; i < n_ports; i++) {
490		port[i] = kzalloc(sizeof(**port), flags);
491		if (port[i] == NULL)
492			goto out;
493		port[i]->num = i;
494		port[i]->async = hsi_dummy_msg;
495		port[i]->setup = hsi_dummy_cl;
496		port[i]->flush = hsi_dummy_cl;
497		port[i]->start_tx = hsi_dummy_cl;
498		port[i]->stop_tx = hsi_dummy_cl;
499		port[i]->release = hsi_dummy_cl;
500		mutex_init(&port[i]->lock);
501		ATOMIC_INIT_NOTIFIER_HEAD(&port[i]->n_head);
502		dev_set_name(&port[i]->device, "port%d", i);
503		hsi->port[i]->device.release = hsi_port_release;
504		device_initialize(&hsi->port[i]->device);
505	}
506
507	return hsi;
508out:
509	hsi_put_controller(hsi);
510
511	return NULL;
512}
513EXPORT_SYMBOL_GPL(hsi_alloc_controller);
514
515/**
516 * hsi_free_msg - Free an HSI message
517 * @msg: Pointer to the HSI message
518 *
519 * Client is responsible to free the buffers pointed by the scatterlists.
520 */
521void hsi_free_msg(struct hsi_msg *msg)
522{
523	if (!msg)
524		return;
525	sg_free_table(&msg->sgt);
526	kfree(msg);
527}
528EXPORT_SYMBOL_GPL(hsi_free_msg);
529
530/**
531 * hsi_alloc_msg - Allocate an HSI message
532 * @nents: Number of memory entries
533 * @flags: Kernel allocation flags
534 *
535 * nents can be 0. This mainly makes sense for read transfer.
536 * In that case, HSI drivers will call the complete callback when
537 * there is data to be read without consuming it.
538 *
539 * Return NULL on failure or a pointer to an hsi_msg on success.
540 */
541struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
542{
543	struct hsi_msg *msg;
544	int err;
545
546	msg = kzalloc(sizeof(*msg), flags);
547	if (!msg)
548		return NULL;
549
550	if (!nents)
551		return msg;
552
553	err = sg_alloc_table(&msg->sgt, nents, flags);
554	if (unlikely(err)) {
555		kfree(msg);
556		msg = NULL;
557	}
558
559	return msg;
560}
561EXPORT_SYMBOL_GPL(hsi_alloc_msg);
562
563/**
564 * hsi_async - Submit an HSI transfer to the controller
565 * @cl: HSI client sending the transfer
566 * @msg: The HSI transfer passed to controller
567 *
568 * The HSI message must have the channel, ttype, complete and destructor
569 * fields set beforehand. If nents > 0 then the client has to initialize
570 * also the scatterlists to point to the buffers to write to or read from.
571 *
572 * HSI controllers relay on pre-allocated buffers from their clients and they
573 * do not allocate buffers on their own.
574 *
575 * Once the HSI message transfer finishes, the HSI controller calls the
576 * complete callback with the status and actual_len fields of the HSI message
577 * updated. The complete callback can be called before returning from
578 * hsi_async.
579 *
580 * Returns -errno on failure or 0 on success
581 */
582int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
583{
584	struct hsi_port *port = hsi_get_port(cl);
585
586	if (!hsi_port_claimed(cl))
587		return -EACCES;
588
589	WARN_ON_ONCE(!msg->destructor || !msg->complete);
590	msg->cl = cl;
591
592	return port->async(msg);
593}
594EXPORT_SYMBOL_GPL(hsi_async);
595
596/**
597 * hsi_claim_port - Claim the HSI client's port
598 * @cl: HSI client that wants to claim its port
599 * @share: Flag to indicate if the client wants to share the port or not.
600 *
601 * Returns -errno on failure, 0 on success.
602 */
603int hsi_claim_port(struct hsi_client *cl, unsigned int share)
604{
605	struct hsi_port *port = hsi_get_port(cl);
606	int err = 0;
607
608	mutex_lock(&port->lock);
609	if ((port->claimed) && (!port->shared || !share)) {
610		err = -EBUSY;
611		goto out;
612	}
613	if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
614		err = -ENODEV;
615		goto out;
616	}
617	port->claimed++;
618	port->shared = !!share;
619	cl->pclaimed = 1;
620out:
621	mutex_unlock(&port->lock);
622
623	return err;
624}
625EXPORT_SYMBOL_GPL(hsi_claim_port);
626
627/**
628 * hsi_release_port - Release the HSI client's port
629 * @cl: HSI client which previously claimed its port
630 */
631void hsi_release_port(struct hsi_client *cl)
632{
633	struct hsi_port *port = hsi_get_port(cl);
634
635	mutex_lock(&port->lock);
636	/* Allow HW driver to do some cleanup */
637	port->release(cl);
638	if (cl->pclaimed)
639		port->claimed--;
640	BUG_ON(port->claimed < 0);
641	cl->pclaimed = 0;
642	if (!port->claimed)
643		port->shared = 0;
644	module_put(to_hsi_controller(port->device.parent)->owner);
645	mutex_unlock(&port->lock);
646}
647EXPORT_SYMBOL_GPL(hsi_release_port);
648
649static int hsi_event_notifier_call(struct notifier_block *nb,
650				unsigned long event, void *data __maybe_unused)
651{
652	struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
653
654	(*cl->ehandler)(cl, event);
655
656	return 0;
657}
658
659/**
660 * hsi_register_port_event - Register a client to receive port events
661 * @cl: HSI client that wants to receive port events
662 * @handler: Event handler callback
663 *
664 * Clients should register a callback to be able to receive
665 * events from the ports. Registration should happen after
666 * claiming the port.
667 * The handler can be called in interrupt context.
668 *
669 * Returns -errno on error, or 0 on success.
670 */
671int hsi_register_port_event(struct hsi_client *cl,
672			void (*handler)(struct hsi_client *, unsigned long))
673{
674	struct hsi_port *port = hsi_get_port(cl);
675
676	if (!handler || cl->ehandler)
677		return -EINVAL;
678	if (!hsi_port_claimed(cl))
679		return -EACCES;
680	cl->ehandler = handler;
681	cl->nb.notifier_call = hsi_event_notifier_call;
682
683	return atomic_notifier_chain_register(&port->n_head, &cl->nb);
684}
685EXPORT_SYMBOL_GPL(hsi_register_port_event);
686
687/**
688 * hsi_unregister_port_event - Stop receiving port events for a client
689 * @cl: HSI client that wants to stop receiving port events
690 *
691 * Clients should call this function before releasing their associated
692 * port.
693 *
694 * Returns -errno on error, or 0 on success.
695 */
696int hsi_unregister_port_event(struct hsi_client *cl)
697{
698	struct hsi_port *port = hsi_get_port(cl);
699	int err;
700
701	WARN_ON(!hsi_port_claimed(cl));
702
703	err = atomic_notifier_chain_unregister(&port->n_head, &cl->nb);
704	if (!err)
705		cl->ehandler = NULL;
706
707	return err;
708}
709EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
710
711/**
712 * hsi_event - Notifies clients about port events
713 * @port: Port where the event occurred
714 * @event: The event type
715 *
716 * Clients should not be concerned about wake line behavior. However, due
717 * to a race condition in HSI HW protocol, clients need to be notified
718 * about wake line changes, so they can implement a workaround for it.
719 *
720 * Events:
721 * HSI_EVENT_START_RX - Incoming wake line high
722 * HSI_EVENT_STOP_RX - Incoming wake line down
723 *
724 * Returns -errno on error, or 0 on success.
725 */
726int hsi_event(struct hsi_port *port, unsigned long event)
727{
728	return atomic_notifier_call_chain(&port->n_head, event, NULL);
729}
730EXPORT_SYMBOL_GPL(hsi_event);
731
732/**
733 * hsi_get_channel_id_by_name - acquire channel id by channel name
734 * @cl: HSI client, which uses the channel
735 * @name: name the channel is known under
736 *
737 * Clients can call this function to get the hsi channel ids similar to
738 * requesting IRQs or GPIOs by name. This function assumes the same
739 * channel configuration is used for RX and TX.
740 *
741 * Returns -errno on error or channel id on success.
742 */
743int hsi_get_channel_id_by_name(struct hsi_client *cl, char *name)
744{
745	int i;
746
747	if (!cl->rx_cfg.channels)
748		return -ENOENT;
749
750	for (i = 0; i < cl->rx_cfg.num_channels; i++)
751		if (!strcmp(cl->rx_cfg.channels[i].name, name))
752			return cl->rx_cfg.channels[i].id;
753
754	return -ENXIO;
755}
756EXPORT_SYMBOL_GPL(hsi_get_channel_id_by_name);
757
758static int __init hsi_init(void)
759{
760	return bus_register(&hsi_bus_type);
761}
762postcore_initcall(hsi_init);
763
764static void __exit hsi_exit(void)
765{
766	bus_unregister(&hsi_bus_type);
767}
768module_exit(hsi_exit);
769
770MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
771MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
772MODULE_LICENSE("GPL v2");
773