sysctl: range checking in do_proc_dointvec_ms_jiffies_conv
[linux/fpc-iii.git] / drivers / hsi / hsi.c
blob66d44581e1b1e74a242a8b8cdbf28ac3196325c3
1 /*
2 * HSI core.
4 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
6 * Contact: Carlos Chinea <carlos.chinea@nokia.com>
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.
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.
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
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 "hsi_core.h"
31 static ssize_t modalias_show(struct device *dev,
32 struct device_attribute *a __maybe_unused, char *buf)
34 return sprintf(buf, "hsi:%s\n", dev_name(dev));
37 static struct device_attribute hsi_bus_dev_attrs[] = {
38 __ATTR_RO(modalias),
39 __ATTR_NULL,
42 static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
44 add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));
46 return 0;
49 static int hsi_bus_match(struct device *dev, struct device_driver *driver)
51 return strcmp(dev_name(dev), driver->name) == 0;
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,
61 static void hsi_client_release(struct device *dev)
63 kfree(to_hsi_client(dev));
66 static void hsi_new_client(struct hsi_port *port, struct hsi_board_info *info)
68 struct hsi_client *cl;
70 cl = kzalloc(sizeof(*cl), GFP_KERNEL);
71 if (!cl)
72 return;
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, "%s", info->name);
79 cl->device.platform_data = info->platform_data;
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);
84 put_device(&cl->device);
88 static void hsi_scan_board_info(struct hsi_controller *hsi)
90 struct hsi_cl_info *cl_info;
91 struct hsi_port *p;
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);
102 static int hsi_remove_client(struct device *dev, void *data __maybe_unused)
104 device_unregister(dev);
106 return 0;
109 static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
111 device_for_each_child(dev, NULL, hsi_remove_client);
112 device_unregister(dev);
114 return 0;
117 static void hsi_controller_release(struct device *dev)
119 struct hsi_controller *hsi = to_hsi_controller(dev);
121 kfree(hsi->port);
122 kfree(hsi);
125 static void hsi_port_release(struct device *dev)
127 kfree(to_hsi_port(dev));
131 * hsi_unregister_controller - Unregister an HSI controller
132 * @hsi: The HSI controller to register
134 void hsi_unregister_controller(struct hsi_controller *hsi)
136 device_for_each_child(&hsi->device, NULL, hsi_remove_port);
137 device_unregister(&hsi->device);
139 EXPORT_SYMBOL_GPL(hsi_unregister_controller);
142 * hsi_register_controller - Register an HSI controller and its ports
143 * @hsi: The HSI controller to register
145 * Returns -errno on failure, 0 on success.
147 int hsi_register_controller(struct hsi_controller *hsi)
149 unsigned int i;
150 int err;
152 err = device_add(&hsi->device);
153 if (err < 0)
154 return err;
155 for (i = 0; i < hsi->num_ports; i++) {
156 hsi->port[i]->device.parent = &hsi->device;
157 err = device_add(&hsi->port[i]->device);
158 if (err < 0)
159 goto out;
161 /* Populate HSI bus with HSI clients */
162 hsi_scan_board_info(hsi);
164 return 0;
165 out:
166 while (i-- > 0)
167 device_del(&hsi->port[i]->device);
168 device_del(&hsi->device);
170 return err;
172 EXPORT_SYMBOL_GPL(hsi_register_controller);
175 * hsi_register_client_driver - Register an HSI client to the HSI bus
176 * @drv: HSI client driver to register
178 * Returns -errno on failure, 0 on success.
180 int hsi_register_client_driver(struct hsi_client_driver *drv)
182 drv->driver.bus = &hsi_bus_type;
184 return driver_register(&drv->driver);
186 EXPORT_SYMBOL_GPL(hsi_register_client_driver);
188 static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
190 return 0;
193 static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
195 return 0;
199 * hsi_put_controller - Free an HSI controller
201 * @hsi: Pointer to the HSI controller to freed
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.
207 void hsi_put_controller(struct hsi_controller *hsi)
209 unsigned int i;
211 if (!hsi)
212 return;
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);
219 EXPORT_SYMBOL_GPL(hsi_put_controller);
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
226 * Return NULL on failure or a pointer to an hsi_controller on success.
228 struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
230 struct hsi_controller *hsi;
231 struct hsi_port **port;
232 unsigned int i;
234 if (!n_ports)
235 return NULL;
237 hsi = kzalloc(sizeof(*hsi), flags);
238 if (!hsi)
239 return NULL;
240 port = kzalloc(sizeof(*port)*n_ports, flags);
241 if (!port) {
242 kfree(hsi);
243 return NULL;
245 hsi->num_ports = n_ports;
246 hsi->port = port;
247 hsi->device.release = hsi_controller_release;
248 device_initialize(&hsi->device);
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);
262 ATOMIC_INIT_NOTIFIER_HEAD(&port[i]->n_head);
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);
268 return hsi;
269 out:
270 hsi_put_controller(hsi);
272 return NULL;
274 EXPORT_SYMBOL_GPL(hsi_alloc_controller);
277 * hsi_free_msg - Free an HSI message
278 * @msg: Pointer to the HSI message
280 * Client is responsible to free the buffers pointed by the scatterlists.
282 void hsi_free_msg(struct hsi_msg *msg)
284 if (!msg)
285 return;
286 sg_free_table(&msg->sgt);
287 kfree(msg);
289 EXPORT_SYMBOL_GPL(hsi_free_msg);
292 * hsi_alloc_msg - Allocate an HSI message
293 * @nents: Number of memory entries
294 * @flags: Kernel allocation flags
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.
300 * Return NULL on failure or a pointer to an hsi_msg on success.
302 struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
304 struct hsi_msg *msg;
305 int err;
307 msg = kzalloc(sizeof(*msg), flags);
308 if (!msg)
309 return NULL;
311 if (!nents)
312 return msg;
314 err = sg_alloc_table(&msg->sgt, nents, flags);
315 if (unlikely(err)) {
316 kfree(msg);
317 msg = NULL;
320 return msg;
322 EXPORT_SYMBOL_GPL(hsi_alloc_msg);
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
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.
333 * HSI controllers relay on pre-allocated buffers from their clients and they
334 * do not allocate buffers on their own.
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.
341 * Returns -errno on failure or 0 on success
343 int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
345 struct hsi_port *port = hsi_get_port(cl);
347 if (!hsi_port_claimed(cl))
348 return -EACCES;
350 WARN_ON_ONCE(!msg->destructor || !msg->complete);
351 msg->cl = cl;
353 return port->async(msg);
355 EXPORT_SYMBOL_GPL(hsi_async);
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.
362 * Returns -errno on failure, 0 on success.
364 int hsi_claim_port(struct hsi_client *cl, unsigned int share)
366 struct hsi_port *port = hsi_get_port(cl);
367 int err = 0;
369 mutex_lock(&port->lock);
370 if ((port->claimed) && (!port->shared || !share)) {
371 err = -EBUSY;
372 goto out;
374 if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
375 err = -ENODEV;
376 goto out;
378 port->claimed++;
379 port->shared = !!share;
380 cl->pclaimed = 1;
381 out:
382 mutex_unlock(&port->lock);
384 return err;
386 EXPORT_SYMBOL_GPL(hsi_claim_port);
389 * hsi_release_port - Release the HSI client's port
390 * @cl: HSI client which previously claimed its port
392 void hsi_release_port(struct hsi_client *cl)
394 struct hsi_port *port = hsi_get_port(cl);
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);
408 EXPORT_SYMBOL_GPL(hsi_release_port);
410 static int hsi_event_notifier_call(struct notifier_block *nb,
411 unsigned long event, void *data __maybe_unused)
413 struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
415 (*cl->ehandler)(cl, event);
417 return 0;
421 * hsi_register_port_event - Register a client to receive port events
422 * @cl: HSI client that wants to receive port events
423 * @handler: Event handler callback
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.
430 * Returns -errno on error, or 0 on success.
432 int hsi_register_port_event(struct hsi_client *cl,
433 void (*handler)(struct hsi_client *, unsigned long))
435 struct hsi_port *port = hsi_get_port(cl);
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;
444 return atomic_notifier_chain_register(&port->n_head, &cl->nb);
446 EXPORT_SYMBOL_GPL(hsi_register_port_event);
449 * hsi_unregister_port_event - Stop receiving port events for a client
450 * @cl: HSI client that wants to stop receiving port events
452 * Clients should call this function before releasing their associated
453 * port.
455 * Returns -errno on error, or 0 on success.
457 int hsi_unregister_port_event(struct hsi_client *cl)
459 struct hsi_port *port = hsi_get_port(cl);
460 int err;
462 WARN_ON(!hsi_port_claimed(cl));
464 err = atomic_notifier_chain_unregister(&port->n_head, &cl->nb);
465 if (!err)
466 cl->ehandler = NULL;
468 return err;
470 EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
473 * hsi_event -Notifies clients about port events
474 * @port: Port where the event occurred
475 * @event: The event type
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.
481 * Events:
482 * HSI_EVENT_START_RX - Incoming wake line high
483 * HSI_EVENT_STOP_RX - Incoming wake line down
485 * Returns -errno on error, or 0 on success.
487 int hsi_event(struct hsi_port *port, unsigned long event)
489 return atomic_notifier_call_chain(&port->n_head, event, NULL);
491 EXPORT_SYMBOL_GPL(hsi_event);
493 static int __init hsi_init(void)
495 return bus_register(&hsi_bus_type);
497 postcore_initcall(hsi_init);
499 static void __exit hsi_exit(void)
501 bus_unregister(&hsi_bus_type);
503 module_exit(hsi_exit);
505 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
506 MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
507 MODULE_LICENSE("GPL v2");