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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 goto err;
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 = kmemdup(info->tx_cfg.channels, size,
94 GFP_KERNEL);
95 if (!cl->tx_cfg.channels)
96 goto err_tx;
97 }
98
99 cl->rx_cfg = info->rx_cfg;
100 if (cl->rx_cfg.channels) {
101 size = cl->rx_cfg.num_channels * sizeof(*cl->rx_cfg.channels);
102 cl->rx_cfg.channels = kmemdup(info->rx_cfg.channels, size,
103 GFP_KERNEL);
104 if (!cl->rx_cfg.channels)
105 goto err_rx;
106 }
107
108 cl->device.bus = &hsi_bus_type;
109 cl->device.parent = &port->device;
110 cl->device.release = hsi_client_release;
111 dev_set_name(&cl->device, "%s", info->name);
112 cl->device.platform_data = info->platform_data;
113 if (info->archdata)
114 cl->device.archdata = *info->archdata;
115 if (device_register(&cl->device) < 0) {
116 pr_err("hsi: failed to register client: %s\n", info->name);
117 put_device(&cl->device);
118 }
119
120 return cl;
121err_rx:
122 kfree(cl->tx_cfg.channels);
123err_tx:
124 kfree(cl);
125err:
126 return NULL;
127}
128EXPORT_SYMBOL_GPL(hsi_new_client);
129
130static void hsi_scan_board_info(struct hsi_controller *hsi)
131{
132 struct hsi_cl_info *cl_info;
133 struct hsi_port *p;
134
135 list_for_each_entry(cl_info, &hsi_board_list, list)
136 if (cl_info->info.hsi_id == hsi->id) {
137 p = hsi_find_port_num(hsi, cl_info->info.port);
138 if (!p)
139 continue;
140 hsi_new_client(p, &cl_info->info);
141 }
142}
143
144#ifdef CONFIG_OF
145static struct hsi_board_info hsi_char_dev_info = {
146 .name = "hsi_char",
147};
148
149static int hsi_of_property_parse_mode(struct device_node *client, char *name,
150 unsigned int *result)
151{
152 const char *mode;
153 int err;
154
155 err = of_property_read_string(client, name, &mode);
156 if (err < 0)
157 return err;
158
159 if (strcmp(mode, "stream") == 0)
160 *result = HSI_MODE_STREAM;
161 else if (strcmp(mode, "frame") == 0)
162 *result = HSI_MODE_FRAME;
163 else
164 return -EINVAL;
165
166 return 0;
167}
168
169static int hsi_of_property_parse_flow(struct device_node *client, char *name,
170 unsigned int *result)
171{
172 const char *flow;
173 int err;
174
175 err = of_property_read_string(client, name, &flow);
176 if (err < 0)
177 return err;
178
179 if (strcmp(flow, "synchronized") == 0)
180 *result = HSI_FLOW_SYNC;
181 else if (strcmp(flow, "pipeline") == 0)
182 *result = HSI_FLOW_PIPE;
183 else
184 return -EINVAL;
185
186 return 0;
187}
188
189static int hsi_of_property_parse_arb_mode(struct device_node *client,
190 char *name, unsigned int *result)
191{
192 const char *arb_mode;
193 int err;
194
195 err = of_property_read_string(client, name, &arb_mode);
196 if (err < 0)
197 return err;
198
199 if (strcmp(arb_mode, "round-robin") == 0)
200 *result = HSI_ARB_RR;
201 else if (strcmp(arb_mode, "priority") == 0)
202 *result = HSI_ARB_PRIO;
203 else
204 return -EINVAL;
205
206 return 0;
207}
208
209static void hsi_add_client_from_dt(struct hsi_port *port,
210 struct device_node *client)
211{
212 struct hsi_client *cl;
213 struct hsi_channel channel;
214 struct property *prop;
215 char name[32];
216 int length, cells, err, i, max_chan, mode;
217
218 cl = kzalloc(sizeof(*cl), GFP_KERNEL);
219 if (!cl)
220 return;
221
222 err = of_modalias_node(client, name, sizeof(name));
223 if (err)
224 goto err;
225
226 dev_set_name(&cl->device, "%s", name);
227
228 err = hsi_of_property_parse_mode(client, "hsi-mode", &mode);
229 if (err) {
230 err = hsi_of_property_parse_mode(client, "hsi-rx-mode",
231 &cl->rx_cfg.mode);
232 if (err)
233 goto err;
234
235 err = hsi_of_property_parse_mode(client, "hsi-tx-mode",
236 &cl->tx_cfg.mode);
237 if (err)
238 goto err;
239 } else {
240 cl->rx_cfg.mode = mode;
241 cl->tx_cfg.mode = mode;
242 }
243
244 err = of_property_read_u32(client, "hsi-speed-kbps",
245 &cl->tx_cfg.speed);
246 if (err)
247 goto err;
248 cl->rx_cfg.speed = cl->tx_cfg.speed;
249
250 err = hsi_of_property_parse_flow(client, "hsi-flow",
251 &cl->rx_cfg.flow);
252 if (err)
253 goto err;
254
255 err = hsi_of_property_parse_arb_mode(client, "hsi-arb-mode",
256 &cl->rx_cfg.arb_mode);
257 if (err)
258 goto err;
259
260 prop = of_find_property(client, "hsi-channel-ids", &length);
261 if (!prop) {
262 err = -EINVAL;
263 goto err;
264 }
265
266 cells = length / sizeof(u32);
267
268 cl->rx_cfg.num_channels = cells;
269 cl->tx_cfg.num_channels = cells;
270 cl->rx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
271 if (!cl->rx_cfg.channels) {
272 err = -ENOMEM;
273 goto err;
274 }
275
276 cl->tx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
277 if (!cl->tx_cfg.channels) {
278 err = -ENOMEM;
279 goto err2;
280 }
281
282 max_chan = 0;
283 for (i = 0; i < cells; i++) {
284 err = of_property_read_u32_index(client, "hsi-channel-ids", i,
285 &channel.id);
286 if (err)
287 goto err3;
288
289 err = of_property_read_string_index(client, "hsi-channel-names",
290 i, &channel.name);
291 if (err)
292 channel.name = NULL;
293
294 if (channel.id > max_chan)
295 max_chan = channel.id;
296
297 cl->rx_cfg.channels[i] = channel;
298 cl->tx_cfg.channels[i] = channel;
299 }
300
301 cl->rx_cfg.num_hw_channels = max_chan + 1;
302 cl->tx_cfg.num_hw_channels = max_chan + 1;
303
304 cl->device.bus = &hsi_bus_type;
305 cl->device.parent = &port->device;
306 cl->device.release = hsi_client_release;
307 cl->device.of_node = client;
308
309 if (device_register(&cl->device) < 0) {
310 pr_err("hsi: failed to register client: %s\n", name);
311 put_device(&cl->device);
312 }
313
314 return;
315
316err3:
317 kfree(cl->tx_cfg.channels);
318err2:
319 kfree(cl->rx_cfg.channels);
320err:
321 kfree(cl);
322 pr_err("hsi client: missing or incorrect of property: err=%d\n", err);
323}
324
325void hsi_add_clients_from_dt(struct hsi_port *port, struct device_node *clients)
326{
327 struct device_node *child;
328
329 /* register hsi-char device */
330 hsi_new_client(port, &hsi_char_dev_info);
331
332 for_each_available_child_of_node(clients, child)
333 hsi_add_client_from_dt(port, child);
334}
335EXPORT_SYMBOL_GPL(hsi_add_clients_from_dt);
336#endif
337
338int hsi_remove_client(struct device *dev, void *data __maybe_unused)
339{
340 device_unregister(dev);
341
342 return 0;
343}
344EXPORT_SYMBOL_GPL(hsi_remove_client);
345
346static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
347{
348 device_for_each_child(dev, NULL, hsi_remove_client);
349 device_unregister(dev);
350
351 return 0;
352}
353
354static void hsi_controller_release(struct device *dev)
355{
356 struct hsi_controller *hsi = to_hsi_controller(dev);
357
358 kfree(hsi->port);
359 kfree(hsi);
360}
361
362static void hsi_port_release(struct device *dev)
363{
364 kfree(to_hsi_port(dev));
365}
366
367/**
368 * hsi_unregister_port - Unregister an HSI port
369 * @port: The HSI port to unregister
370 */
371void hsi_port_unregister_clients(struct hsi_port *port)
372{
373 device_for_each_child(&port->device, NULL, hsi_remove_client);
374}
375EXPORT_SYMBOL_GPL(hsi_port_unregister_clients);
376
377/**
378 * hsi_unregister_controller - Unregister an HSI controller
379 * @hsi: The HSI controller to register
380 */
381void hsi_unregister_controller(struct hsi_controller *hsi)
382{
383 device_for_each_child(&hsi->device, NULL, hsi_remove_port);
384 device_unregister(&hsi->device);
385}
386EXPORT_SYMBOL_GPL(hsi_unregister_controller);
387
388/**
389 * hsi_register_controller - Register an HSI controller and its ports
390 * @hsi: The HSI controller to register
391 *
392 * Returns -errno on failure, 0 on success.
393 */
394int hsi_register_controller(struct hsi_controller *hsi)
395{
396 unsigned int i;
397 int err;
398
399 err = device_add(&hsi->device);
400 if (err < 0)
401 return err;
402 for (i = 0; i < hsi->num_ports; i++) {
403 hsi->port[i]->device.parent = &hsi->device;
404 err = device_add(&hsi->port[i]->device);
405 if (err < 0)
406 goto out;
407 }
408 /* Populate HSI bus with HSI clients */
409 hsi_scan_board_info(hsi);
410
411 return 0;
412out:
413 while (i-- > 0)
414 device_del(&hsi->port[i]->device);
415 device_del(&hsi->device);
416
417 return err;
418}
419EXPORT_SYMBOL_GPL(hsi_register_controller);
420
421/**
422 * hsi_register_client_driver - Register an HSI client to the HSI bus
423 * @drv: HSI client driver to register
424 *
425 * Returns -errno on failure, 0 on success.
426 */
427int hsi_register_client_driver(struct hsi_client_driver *drv)
428{
429 drv->driver.bus = &hsi_bus_type;
430
431 return driver_register(&drv->driver);
432}
433EXPORT_SYMBOL_GPL(hsi_register_client_driver);
434
435static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
436{
437 return 0;
438}
439
440static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
441{
442 return 0;
443}
444
445/**
446 * hsi_put_controller - Free an HSI controller
447 *
448 * @hsi: Pointer to the HSI controller to freed
449 *
450 * HSI controller drivers should only use this function if they need
451 * to free their allocated hsi_controller structures before a successful
452 * call to hsi_register_controller. Other use is not allowed.
453 */
454void hsi_put_controller(struct hsi_controller *hsi)
455{
456 unsigned int i;
457
458 if (!hsi)
459 return;
460
461 for (i = 0; i < hsi->num_ports; i++)
462 if (hsi->port && hsi->port[i])
463 put_device(&hsi->port[i]->device);
464 put_device(&hsi->device);
465}
466EXPORT_SYMBOL_GPL(hsi_put_controller);
467
468/**
469 * hsi_alloc_controller - Allocate an HSI controller and its ports
470 * @n_ports: Number of ports on the HSI controller
471 * @flags: Kernel allocation flags
472 *
473 * Return NULL on failure or a pointer to an hsi_controller on success.
474 */
475struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
476{
477 struct hsi_controller *hsi;
478 struct hsi_port **port;
479 unsigned int i;
480
481 if (!n_ports)
482 return NULL;
483
484 hsi = kzalloc(sizeof(*hsi), flags);
485 if (!hsi)
486 return NULL;
487 port = kcalloc(n_ports, sizeof(*port), flags);
488 if (!port) {
489 kfree(hsi);
490 return NULL;
491 }
492 hsi->num_ports = n_ports;
493 hsi->port = port;
494 hsi->device.release = hsi_controller_release;
495 device_initialize(&hsi->device);
496
497 for (i = 0; i < n_ports; i++) {
498 port[i] = kzalloc(sizeof(**port), flags);
499 if (port[i] == NULL)
500 goto out;
501 port[i]->num = i;
502 port[i]->async = hsi_dummy_msg;
503 port[i]->setup = hsi_dummy_cl;
504 port[i]->flush = hsi_dummy_cl;
505 port[i]->start_tx = hsi_dummy_cl;
506 port[i]->stop_tx = hsi_dummy_cl;
507 port[i]->release = hsi_dummy_cl;
508 mutex_init(&port[i]->lock);
509 BLOCKING_INIT_NOTIFIER_HEAD(&port[i]->n_head);
510 dev_set_name(&port[i]->device, "port%d", i);
511 hsi->port[i]->device.release = hsi_port_release;
512 device_initialize(&hsi->port[i]->device);
513 }
514
515 return hsi;
516out:
517 hsi_put_controller(hsi);
518
519 return NULL;
520}
521EXPORT_SYMBOL_GPL(hsi_alloc_controller);
522
523/**
524 * hsi_free_msg - Free an HSI message
525 * @msg: Pointer to the HSI message
526 *
527 * Client is responsible to free the buffers pointed by the scatterlists.
528 */
529void hsi_free_msg(struct hsi_msg *msg)
530{
531 if (!msg)
532 return;
533 sg_free_table(&msg->sgt);
534 kfree(msg);
535}
536EXPORT_SYMBOL_GPL(hsi_free_msg);
537
538/**
539 * hsi_alloc_msg - Allocate an HSI message
540 * @nents: Number of memory entries
541 * @flags: Kernel allocation flags
542 *
543 * nents can be 0. This mainly makes sense for read transfer.
544 * In that case, HSI drivers will call the complete callback when
545 * there is data to be read without consuming it.
546 *
547 * Return NULL on failure or a pointer to an hsi_msg on success.
548 */
549struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
550{
551 struct hsi_msg *msg;
552 int err;
553
554 msg = kzalloc(sizeof(*msg), flags);
555 if (!msg)
556 return NULL;
557
558 if (!nents)
559 return msg;
560
561 err = sg_alloc_table(&msg->sgt, nents, flags);
562 if (unlikely(err)) {
563 kfree(msg);
564 msg = NULL;
565 }
566
567 return msg;
568}
569EXPORT_SYMBOL_GPL(hsi_alloc_msg);
570
571/**
572 * hsi_async - Submit an HSI transfer to the controller
573 * @cl: HSI client sending the transfer
574 * @msg: The HSI transfer passed to controller
575 *
576 * The HSI message must have the channel, ttype, complete and destructor
577 * fields set beforehand. If nents > 0 then the client has to initialize
578 * also the scatterlists to point to the buffers to write to or read from.
579 *
580 * HSI controllers relay on pre-allocated buffers from their clients and they
581 * do not allocate buffers on their own.
582 *
583 * Once the HSI message transfer finishes, the HSI controller calls the
584 * complete callback with the status and actual_len fields of the HSI message
585 * updated. The complete callback can be called before returning from
586 * hsi_async.
587 *
588 * Returns -errno on failure or 0 on success
589 */
590int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
591{
592 struct hsi_port *port = hsi_get_port(cl);
593
594 if (!hsi_port_claimed(cl))
595 return -EACCES;
596
597 WARN_ON_ONCE(!msg->destructor || !msg->complete);
598 msg->cl = cl;
599
600 return port->async(msg);
601}
602EXPORT_SYMBOL_GPL(hsi_async);
603
604/**
605 * hsi_claim_port - Claim the HSI client's port
606 * @cl: HSI client that wants to claim its port
607 * @share: Flag to indicate if the client wants to share the port or not.
608 *
609 * Returns -errno on failure, 0 on success.
610 */
611int hsi_claim_port(struct hsi_client *cl, unsigned int share)
612{
613 struct hsi_port *port = hsi_get_port(cl);
614 int err = 0;
615
616 mutex_lock(&port->lock);
617 if ((port->claimed) && (!port->shared || !share)) {
618 err = -EBUSY;
619 goto out;
620 }
621 if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
622 err = -ENODEV;
623 goto out;
624 }
625 port->claimed++;
626 port->shared = !!share;
627 cl->pclaimed = 1;
628out:
629 mutex_unlock(&port->lock);
630
631 return err;
632}
633EXPORT_SYMBOL_GPL(hsi_claim_port);
634
635/**
636 * hsi_release_port - Release the HSI client's port
637 * @cl: HSI client which previously claimed its port
638 */
639void hsi_release_port(struct hsi_client *cl)
640{
641 struct hsi_port *port = hsi_get_port(cl);
642
643 mutex_lock(&port->lock);
644 /* Allow HW driver to do some cleanup */
645 port->release(cl);
646 if (cl->pclaimed)
647 port->claimed--;
648 BUG_ON(port->claimed < 0);
649 cl->pclaimed = 0;
650 if (!port->claimed)
651 port->shared = 0;
652 module_put(to_hsi_controller(port->device.parent)->owner);
653 mutex_unlock(&port->lock);
654}
655EXPORT_SYMBOL_GPL(hsi_release_port);
656
657static int hsi_event_notifier_call(struct notifier_block *nb,
658 unsigned long event, void *data __maybe_unused)
659{
660 struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
661
662 (*cl->ehandler)(cl, event);
663
664 return 0;
665}
666
667/**
668 * hsi_register_port_event - Register a client to receive port events
669 * @cl: HSI client that wants to receive port events
670 * @handler: Event handler callback
671 *
672 * Clients should register a callback to be able to receive
673 * events from the ports. Registration should happen after
674 * claiming the port.
675 * The handler can be called in interrupt context.
676 *
677 * Returns -errno on error, or 0 on success.
678 */
679int hsi_register_port_event(struct hsi_client *cl,
680 void (*handler)(struct hsi_client *, unsigned long))
681{
682 struct hsi_port *port = hsi_get_port(cl);
683
684 if (!handler || cl->ehandler)
685 return -EINVAL;
686 if (!hsi_port_claimed(cl))
687 return -EACCES;
688 cl->ehandler = handler;
689 cl->nb.notifier_call = hsi_event_notifier_call;
690
691 return blocking_notifier_chain_register(&port->n_head, &cl->nb);
692}
693EXPORT_SYMBOL_GPL(hsi_register_port_event);
694
695/**
696 * hsi_unregister_port_event - Stop receiving port events for a client
697 * @cl: HSI client that wants to stop receiving port events
698 *
699 * Clients should call this function before releasing their associated
700 * port.
701 *
702 * Returns -errno on error, or 0 on success.
703 */
704int hsi_unregister_port_event(struct hsi_client *cl)
705{
706 struct hsi_port *port = hsi_get_port(cl);
707 int err;
708
709 WARN_ON(!hsi_port_claimed(cl));
710
711 err = blocking_notifier_chain_unregister(&port->n_head, &cl->nb);
712 if (!err)
713 cl->ehandler = NULL;
714
715 return err;
716}
717EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
718
719/**
720 * hsi_event - Notifies clients about port events
721 * @port: Port where the event occurred
722 * @event: The event type
723 *
724 * Clients should not be concerned about wake line behavior. However, due
725 * to a race condition in HSI HW protocol, clients need to be notified
726 * about wake line changes, so they can implement a workaround for it.
727 *
728 * Events:
729 * HSI_EVENT_START_RX - Incoming wake line high
730 * HSI_EVENT_STOP_RX - Incoming wake line down
731 *
732 * Returns -errno on error, or 0 on success.
733 */
734int hsi_event(struct hsi_port *port, unsigned long event)
735{
736 return blocking_notifier_call_chain(&port->n_head, event, NULL);
737}
738EXPORT_SYMBOL_GPL(hsi_event);
739
740/**
741 * hsi_get_channel_id_by_name - acquire channel id by channel name
742 * @cl: HSI client, which uses the channel
743 * @name: name the channel is known under
744 *
745 * Clients can call this function to get the hsi channel ids similar to
746 * requesting IRQs or GPIOs by name. This function assumes the same
747 * channel configuration is used for RX and TX.
748 *
749 * Returns -errno on error or channel id on success.
750 */
751int hsi_get_channel_id_by_name(struct hsi_client *cl, char *name)
752{
753 int i;
754
755 if (!cl->rx_cfg.channels)
756 return -ENOENT;
757
758 for (i = 0; i < cl->rx_cfg.num_channels; i++)
759 if (!strcmp(cl->rx_cfg.channels[i].name, name))
760 return cl->rx_cfg.channels[i].id;
761
762 return -ENXIO;
763}
764EXPORT_SYMBOL_GPL(hsi_get_channel_id_by_name);
765
766static int __init hsi_init(void)
767{
768 return bus_register(&hsi_bus_type);
769}
770postcore_initcall(hsi_init);
771
772static void __exit hsi_exit(void)
773{
774 bus_unregister(&hsi_bus_type);
775}
776module_exit(hsi_exit);
777
778MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
779MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
780MODULE_LICENSE("GPL v2");