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