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a056ab8c CC |
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> | |
a056ab8c | 24 | #include <linux/list.h> |
a056ab8c CC |
25 | #include <linux/kobject.h> |
26 | #include <linux/slab.h> | |
27 | #include <linux/string.h> | |
ec1c56ff | 28 | #include <linux/notifier.h> |
a056ab8c CC |
29 | #include "hsi_core.h" |
30 | ||
a056ab8c CC |
31 | static ssize_t modalias_show(struct device *dev, |
32 | struct device_attribute *a __maybe_unused, char *buf) | |
33 | { | |
34 | return sprintf(buf, "hsi:%s\n", dev_name(dev)); | |
35 | } | |
36 | ||
37 | static struct device_attribute hsi_bus_dev_attrs[] = { | |
38 | __ATTR_RO(modalias), | |
39 | __ATTR_NULL, | |
40 | }; | |
41 | ||
42 | static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env) | |
43 | { | |
6f02b9e9 | 44 | add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev)); |
a056ab8c CC |
45 | |
46 | return 0; | |
47 | } | |
48 | ||
49 | static int hsi_bus_match(struct device *dev, struct device_driver *driver) | |
50 | { | |
51 | return strcmp(dev_name(dev), driver->name) == 0; | |
52 | } | |
53 | ||
54 | static struct bus_type hsi_bus_type = { | |
55 | .name = "hsi", | |
56 | .dev_attrs = hsi_bus_dev_attrs, | |
57 | .match = hsi_bus_match, | |
58 | .uevent = hsi_bus_uevent, | |
59 | }; | |
60 | ||
61 | static void hsi_client_release(struct device *dev) | |
62 | { | |
63 | kfree(to_hsi_client(dev)); | |
64 | } | |
65 | ||
66 | static void hsi_new_client(struct hsi_port *port, struct hsi_board_info *info) | |
67 | { | |
68 | struct hsi_client *cl; | |
a056ab8c CC |
69 | |
70 | cl = kzalloc(sizeof(*cl), GFP_KERNEL); | |
71 | if (!cl) | |
72 | return; | |
a056ab8c CC |
73 | cl->tx_cfg = info->tx_cfg; |
74 | cl->rx_cfg = info->rx_cfg; | |
75 | cl->device.bus = &hsi_bus_type; | |
76 | cl->device.parent = &port->device; | |
77 | cl->device.release = hsi_client_release; | |
78 | dev_set_name(&cl->device, info->name); | |
79 | cl->device.platform_data = info->platform_data; | |
a056ab8c CC |
80 | if (info->archdata) |
81 | cl->device.archdata = *info->archdata; | |
82 | if (device_register(&cl->device) < 0) { | |
83 | pr_err("hsi: failed to register client: %s\n", info->name); | |
90e41f9d | 84 | put_device(&cl->device); |
a056ab8c CC |
85 | } |
86 | } | |
87 | ||
88 | static void hsi_scan_board_info(struct hsi_controller *hsi) | |
89 | { | |
90 | struct hsi_cl_info *cl_info; | |
91 | struct hsi_port *p; | |
92 | ||
93 | list_for_each_entry(cl_info, &hsi_board_list, list) | |
94 | if (cl_info->info.hsi_id == hsi->id) { | |
95 | p = hsi_find_port_num(hsi, cl_info->info.port); | |
96 | if (!p) | |
97 | continue; | |
98 | hsi_new_client(p, &cl_info->info); | |
99 | } | |
100 | } | |
101 | ||
102 | static int hsi_remove_client(struct device *dev, void *data __maybe_unused) | |
103 | { | |
a056ab8c CC |
104 | device_unregister(dev); |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | static int hsi_remove_port(struct device *dev, void *data __maybe_unused) | |
110 | { | |
111 | device_for_each_child(dev, NULL, hsi_remove_client); | |
112 | device_unregister(dev); | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
5a218ceb | 117 | static void hsi_controller_release(struct device *dev) |
a056ab8c | 118 | { |
5a218ceb CC |
119 | struct hsi_controller *hsi = to_hsi_controller(dev); |
120 | ||
121 | kfree(hsi->port); | |
122 | kfree(hsi); | |
a056ab8c CC |
123 | } |
124 | ||
5a218ceb | 125 | static void hsi_port_release(struct device *dev) |
a056ab8c | 126 | { |
5a218ceb | 127 | kfree(to_hsi_port(dev)); |
a056ab8c CC |
128 | } |
129 | ||
130 | /** | |
131 | * hsi_unregister_controller - Unregister an HSI controller | |
132 | * @hsi: The HSI controller to register | |
133 | */ | |
134 | void hsi_unregister_controller(struct hsi_controller *hsi) | |
135 | { | |
136 | device_for_each_child(&hsi->device, NULL, hsi_remove_port); | |
137 | device_unregister(&hsi->device); | |
138 | } | |
139 | EXPORT_SYMBOL_GPL(hsi_unregister_controller); | |
140 | ||
141 | /** | |
142 | * hsi_register_controller - Register an HSI controller and its ports | |
143 | * @hsi: The HSI controller to register | |
144 | * | |
145 | * Returns -errno on failure, 0 on success. | |
146 | */ | |
147 | int hsi_register_controller(struct hsi_controller *hsi) | |
148 | { | |
149 | unsigned int i; | |
150 | int err; | |
151 | ||
5a218ceb | 152 | err = device_add(&hsi->device); |
a056ab8c CC |
153 | if (err < 0) |
154 | return err; | |
155 | for (i = 0; i < hsi->num_ports; i++) { | |
5a218ceb | 156 | hsi->port[i]->device.parent = &hsi->device; |
5a218ceb | 157 | err = device_add(&hsi->port[i]->device); |
a056ab8c CC |
158 | if (err < 0) |
159 | goto out; | |
160 | } | |
161 | /* Populate HSI bus with HSI clients */ | |
162 | hsi_scan_board_info(hsi); | |
163 | ||
164 | return 0; | |
165 | out: | |
5a218ceb CC |
166 | while (i-- > 0) |
167 | device_del(&hsi->port[i]->device); | |
168 | device_del(&hsi->device); | |
a056ab8c CC |
169 | |
170 | return err; | |
171 | } | |
172 | EXPORT_SYMBOL_GPL(hsi_register_controller); | |
173 | ||
174 | /** | |
175 | * hsi_register_client_driver - Register an HSI client to the HSI bus | |
176 | * @drv: HSI client driver to register | |
177 | * | |
178 | * Returns -errno on failure, 0 on success. | |
179 | */ | |
180 | int hsi_register_client_driver(struct hsi_client_driver *drv) | |
181 | { | |
182 | drv->driver.bus = &hsi_bus_type; | |
183 | ||
184 | return driver_register(&drv->driver); | |
185 | } | |
186 | EXPORT_SYMBOL_GPL(hsi_register_client_driver); | |
187 | ||
188 | static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused) | |
189 | { | |
190 | return 0; | |
191 | } | |
192 | ||
193 | static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused) | |
194 | { | |
195 | return 0; | |
196 | } | |
197 | ||
5a218ceb CC |
198 | /** |
199 | * hsi_put_controller - Free an HSI controller | |
200 | * | |
201 | * @hsi: Pointer to the HSI controller to freed | |
202 | * | |
203 | * HSI controller drivers should only use this function if they need | |
204 | * to free their allocated hsi_controller structures before a successful | |
205 | * call to hsi_register_controller. Other use is not allowed. | |
206 | */ | |
207 | void hsi_put_controller(struct hsi_controller *hsi) | |
208 | { | |
209 | unsigned int i; | |
210 | ||
211 | if (!hsi) | |
212 | return; | |
213 | ||
214 | for (i = 0; i < hsi->num_ports; i++) | |
215 | if (hsi->port && hsi->port[i]) | |
216 | put_device(&hsi->port[i]->device); | |
217 | put_device(&hsi->device); | |
218 | } | |
219 | EXPORT_SYMBOL_GPL(hsi_put_controller); | |
220 | ||
a056ab8c CC |
221 | /** |
222 | * hsi_alloc_controller - Allocate an HSI controller and its ports | |
223 | * @n_ports: Number of ports on the HSI controller | |
224 | * @flags: Kernel allocation flags | |
225 | * | |
226 | * Return NULL on failure or a pointer to an hsi_controller on success. | |
227 | */ | |
228 | struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags) | |
229 | { | |
230 | struct hsi_controller *hsi; | |
5a218ceb | 231 | struct hsi_port **port; |
a056ab8c CC |
232 | unsigned int i; |
233 | ||
234 | if (!n_ports) | |
235 | return NULL; | |
236 | ||
a056ab8c CC |
237 | hsi = kzalloc(sizeof(*hsi), flags); |
238 | if (!hsi) | |
5a218ceb CC |
239 | return NULL; |
240 | port = kzalloc(sizeof(*port)*n_ports, flags); | |
241 | if (!port) { | |
242 | kfree(hsi); | |
243 | return NULL; | |
a056ab8c CC |
244 | } |
245 | hsi->num_ports = n_ports; | |
246 | hsi->port = port; | |
5a218ceb CC |
247 | hsi->device.release = hsi_controller_release; |
248 | device_initialize(&hsi->device); | |
249 | ||
250 | for (i = 0; i < n_ports; i++) { | |
251 | port[i] = kzalloc(sizeof(**port), flags); | |
252 | if (port[i] == NULL) | |
253 | goto out; | |
254 | port[i]->num = i; | |
255 | port[i]->async = hsi_dummy_msg; | |
256 | port[i]->setup = hsi_dummy_cl; | |
257 | port[i]->flush = hsi_dummy_cl; | |
258 | port[i]->start_tx = hsi_dummy_cl; | |
259 | port[i]->stop_tx = hsi_dummy_cl; | |
260 | port[i]->release = hsi_dummy_cl; | |
261 | mutex_init(&port[i]->lock); | |
ec1c56ff | 262 | ATOMIC_INIT_NOTIFIER_HEAD(&port[i]->n_head); |
5a218ceb CC |
263 | dev_set_name(&port[i]->device, "port%d", i); |
264 | hsi->port[i]->device.release = hsi_port_release; | |
265 | device_initialize(&hsi->port[i]->device); | |
266 | } | |
a056ab8c CC |
267 | |
268 | return hsi; | |
269 | out: | |
5a218ceb | 270 | hsi_put_controller(hsi); |
a056ab8c CC |
271 | |
272 | return NULL; | |
273 | } | |
274 | EXPORT_SYMBOL_GPL(hsi_alloc_controller); | |
275 | ||
a056ab8c CC |
276 | /** |
277 | * hsi_free_msg - Free an HSI message | |
278 | * @msg: Pointer to the HSI message | |
279 | * | |
280 | * Client is responsible to free the buffers pointed by the scatterlists. | |
281 | */ | |
282 | void hsi_free_msg(struct hsi_msg *msg) | |
283 | { | |
284 | if (!msg) | |
285 | return; | |
286 | sg_free_table(&msg->sgt); | |
287 | kfree(msg); | |
288 | } | |
289 | EXPORT_SYMBOL_GPL(hsi_free_msg); | |
290 | ||
291 | /** | |
292 | * hsi_alloc_msg - Allocate an HSI message | |
293 | * @nents: Number of memory entries | |
294 | * @flags: Kernel allocation flags | |
295 | * | |
296 | * nents can be 0. This mainly makes sense for read transfer. | |
297 | * In that case, HSI drivers will call the complete callback when | |
298 | * there is data to be read without consuming it. | |
299 | * | |
300 | * Return NULL on failure or a pointer to an hsi_msg on success. | |
301 | */ | |
302 | struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags) | |
303 | { | |
304 | struct hsi_msg *msg; | |
305 | int err; | |
306 | ||
307 | msg = kzalloc(sizeof(*msg), flags); | |
308 | if (!msg) | |
309 | return NULL; | |
310 | ||
311 | if (!nents) | |
312 | return msg; | |
313 | ||
314 | err = sg_alloc_table(&msg->sgt, nents, flags); | |
315 | if (unlikely(err)) { | |
316 | kfree(msg); | |
317 | msg = NULL; | |
318 | } | |
319 | ||
320 | return msg; | |
321 | } | |
322 | EXPORT_SYMBOL_GPL(hsi_alloc_msg); | |
323 | ||
324 | /** | |
325 | * hsi_async - Submit an HSI transfer to the controller | |
326 | * @cl: HSI client sending the transfer | |
327 | * @msg: The HSI transfer passed to controller | |
328 | * | |
329 | * The HSI message must have the channel, ttype, complete and destructor | |
330 | * fields set beforehand. If nents > 0 then the client has to initialize | |
331 | * also the scatterlists to point to the buffers to write to or read from. | |
332 | * | |
333 | * HSI controllers relay on pre-allocated buffers from their clients and they | |
334 | * do not allocate buffers on their own. | |
335 | * | |
336 | * Once the HSI message transfer finishes, the HSI controller calls the | |
337 | * complete callback with the status and actual_len fields of the HSI message | |
338 | * updated. The complete callback can be called before returning from | |
339 | * hsi_async. | |
340 | * | |
341 | * Returns -errno on failure or 0 on success | |
342 | */ | |
343 | int hsi_async(struct hsi_client *cl, struct hsi_msg *msg) | |
344 | { | |
345 | struct hsi_port *port = hsi_get_port(cl); | |
346 | ||
347 | if (!hsi_port_claimed(cl)) | |
348 | return -EACCES; | |
349 | ||
350 | WARN_ON_ONCE(!msg->destructor || !msg->complete); | |
351 | msg->cl = cl; | |
352 | ||
353 | return port->async(msg); | |
354 | } | |
355 | EXPORT_SYMBOL_GPL(hsi_async); | |
356 | ||
357 | /** | |
358 | * hsi_claim_port - Claim the HSI client's port | |
359 | * @cl: HSI client that wants to claim its port | |
360 | * @share: Flag to indicate if the client wants to share the port or not. | |
361 | * | |
362 | * Returns -errno on failure, 0 on success. | |
363 | */ | |
364 | int hsi_claim_port(struct hsi_client *cl, unsigned int share) | |
365 | { | |
366 | struct hsi_port *port = hsi_get_port(cl); | |
367 | int err = 0; | |
368 | ||
369 | mutex_lock(&port->lock); | |
370 | if ((port->claimed) && (!port->shared || !share)) { | |
371 | err = -EBUSY; | |
372 | goto out; | |
373 | } | |
374 | if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) { | |
375 | err = -ENODEV; | |
376 | goto out; | |
377 | } | |
378 | port->claimed++; | |
379 | port->shared = !!share; | |
380 | cl->pclaimed = 1; | |
381 | out: | |
382 | mutex_unlock(&port->lock); | |
383 | ||
384 | return err; | |
385 | } | |
386 | EXPORT_SYMBOL_GPL(hsi_claim_port); | |
387 | ||
388 | /** | |
389 | * hsi_release_port - Release the HSI client's port | |
390 | * @cl: HSI client which previously claimed its port | |
391 | */ | |
392 | void hsi_release_port(struct hsi_client *cl) | |
393 | { | |
394 | struct hsi_port *port = hsi_get_port(cl); | |
395 | ||
396 | mutex_lock(&port->lock); | |
397 | /* Allow HW driver to do some cleanup */ | |
398 | port->release(cl); | |
399 | if (cl->pclaimed) | |
400 | port->claimed--; | |
401 | BUG_ON(port->claimed < 0); | |
402 | cl->pclaimed = 0; | |
403 | if (!port->claimed) | |
404 | port->shared = 0; | |
405 | module_put(to_hsi_controller(port->device.parent)->owner); | |
406 | mutex_unlock(&port->lock); | |
407 | } | |
408 | EXPORT_SYMBOL_GPL(hsi_release_port); | |
409 | ||
ec1c56ff CC |
410 | static int hsi_event_notifier_call(struct notifier_block *nb, |
411 | unsigned long event, void *data __maybe_unused) | |
a056ab8c | 412 | { |
ec1c56ff CC |
413 | struct hsi_client *cl = container_of(nb, struct hsi_client, nb); |
414 | ||
415 | (*cl->ehandler)(cl, event); | |
a056ab8c CC |
416 | |
417 | return 0; | |
418 | } | |
419 | ||
ec1c56ff CC |
420 | /** |
421 | * hsi_register_port_event - Register a client to receive port events | |
422 | * @cl: HSI client that wants to receive port events | |
423 | * @cb: Event handler callback | |
424 | * | |
425 | * Clients should register a callback to be able to receive | |
426 | * events from the ports. Registration should happen after | |
427 | * claiming the port. | |
428 | * The handler can be called in interrupt context. | |
429 | * | |
430 | * Returns -errno on error, or 0 on success. | |
431 | */ | |
432 | int hsi_register_port_event(struct hsi_client *cl, | |
433 | void (*handler)(struct hsi_client *, unsigned long)) | |
a056ab8c | 434 | { |
ec1c56ff | 435 | struct hsi_port *port = hsi_get_port(cl); |
a056ab8c | 436 | |
ec1c56ff CC |
437 | if (!handler || cl->ehandler) |
438 | return -EINVAL; | |
439 | if (!hsi_port_claimed(cl)) | |
440 | return -EACCES; | |
441 | cl->ehandler = handler; | |
442 | cl->nb.notifier_call = hsi_event_notifier_call; | |
443 | ||
444 | return atomic_notifier_chain_register(&port->n_head, &cl->nb); | |
a056ab8c | 445 | } |
ec1c56ff | 446 | EXPORT_SYMBOL_GPL(hsi_register_port_event); |
a056ab8c | 447 | |
ec1c56ff CC |
448 | /** |
449 | * hsi_unregister_port_event - Stop receiving port events for a client | |
450 | * @cl: HSI client that wants to stop receiving port events | |
451 | * | |
452 | * Clients should call this function before releasing their associated | |
453 | * port. | |
454 | * | |
455 | * Returns -errno on error, or 0 on success. | |
456 | */ | |
457 | int hsi_unregister_port_event(struct hsi_client *cl) | |
a056ab8c | 458 | { |
ec1c56ff CC |
459 | struct hsi_port *port = hsi_get_port(cl); |
460 | int err; | |
a056ab8c | 461 | |
ec1c56ff | 462 | WARN_ON(!hsi_port_claimed(cl)); |
a056ab8c | 463 | |
ec1c56ff CC |
464 | err = atomic_notifier_chain_unregister(&port->n_head, &cl->nb); |
465 | if (!err) | |
466 | cl->ehandler = NULL; | |
467 | ||
468 | return err; | |
a056ab8c | 469 | } |
ec1c56ff | 470 | EXPORT_SYMBOL_GPL(hsi_unregister_port_event); |
a056ab8c CC |
471 | |
472 | /** | |
473 | * hsi_event -Notifies clients about port events | |
474 | * @port: Port where the event occurred | |
475 | * @event: The event type | |
476 | * | |
477 | * Clients should not be concerned about wake line behavior. However, due | |
478 | * to a race condition in HSI HW protocol, clients need to be notified | |
479 | * about wake line changes, so they can implement a workaround for it. | |
480 | * | |
481 | * Events: | |
482 | * HSI_EVENT_START_RX - Incoming wake line high | |
483 | * HSI_EVENT_STOP_RX - Incoming wake line down | |
ec1c56ff CC |
484 | * |
485 | * Returns -errno on error, or 0 on success. | |
a056ab8c | 486 | */ |
ec1c56ff | 487 | int hsi_event(struct hsi_port *port, unsigned long event) |
a056ab8c | 488 | { |
ec1c56ff | 489 | return atomic_notifier_call_chain(&port->n_head, event, NULL); |
a056ab8c CC |
490 | } |
491 | EXPORT_SYMBOL_GPL(hsi_event); | |
492 | ||
493 | static int __init hsi_init(void) | |
494 | { | |
495 | return bus_register(&hsi_bus_type); | |
496 | } | |
497 | postcore_initcall(hsi_init); | |
498 | ||
499 | static void __exit hsi_exit(void) | |
500 | { | |
501 | bus_unregister(&hsi_bus_type); | |
502 | } | |
503 | module_exit(hsi_exit); | |
504 | ||
505 | MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>"); | |
506 | MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework"); | |
507 | MODULE_LICENSE("GPL v2"); |