1/*
2 * NFC hardware simulation driver
3 * Copyright (c) 2013, Intel Corporation.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
14 */
15
16#include <linux/device.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/ctype.h>
20#include <linux/debugfs.h>
21#include <linux/nfc.h>
22#include <net/nfc/nfc.h>
23#include <net/nfc/digital.h>
24
25#define NFCSIM_ERR(d, fmt, args...) nfc_err(&d->nfc_digital_dev->nfc_dev->dev, \
26 "%s: " fmt, __func__, ## args)
27
28#define NFCSIM_DBG(d, fmt, args...) dev_dbg(&d->nfc_digital_dev->nfc_dev->dev, \
29 "%s: " fmt, __func__, ## args)
30
31#define NFCSIM_VERSION "0.2"
32
33#define NFCSIM_MODE_NONE 0
34#define NFCSIM_MODE_INITIATOR 1
35#define NFCSIM_MODE_TARGET 2
36
37#define NFCSIM_CAPABILITIES (NFC_DIGITAL_DRV_CAPS_IN_CRC | \
38 NFC_DIGITAL_DRV_CAPS_TG_CRC)
39
40struct nfcsim {
41 struct nfc_digital_dev *nfc_digital_dev;
42
43 struct work_struct recv_work;
44 struct delayed_work send_work;
45
46 struct nfcsim_link *link_in;
47 struct nfcsim_link *link_out;
48
49 bool up;
50 u8 mode;
51 u8 rf_tech;
52
53 u16 recv_timeout;
54
55 nfc_digital_cmd_complete_t cb;
56 void *arg;
57
58 u8 dropframe;
59};
60
61struct nfcsim_link {
62 struct mutex lock;
63
64 u8 rf_tech;
65 u8 mode;
66
67 u8 shutdown;
68
69 struct sk_buff *skb;
70 wait_queue_head_t recv_wait;
71 u8 cond;
72};
73
74static struct nfcsim_link *nfcsim_link_new(void)
75{
76 struct nfcsim_link *link;
77
78 link = kzalloc(sizeof(struct nfcsim_link), GFP_KERNEL);
79 if (!link)
80 return NULL;
81
82 mutex_init(&link->lock);
83 init_waitqueue_head(&link->recv_wait);
84
85 return link;
86}
87
88static void nfcsim_link_free(struct nfcsim_link *link)
89{
90 dev_kfree_skb(link->skb);
91 kfree(link);
92}
93
94static void nfcsim_link_recv_wake(struct nfcsim_link *link)
95{
96 link->cond = 1;
97 wake_up_interruptible(&link->recv_wait);
98}
99
100static void nfcsim_link_set_skb(struct nfcsim_link *link, struct sk_buff *skb,
101 u8 rf_tech, u8 mode)
102{
103 mutex_lock(&link->lock);
104
105 dev_kfree_skb(link->skb);
106 link->skb = skb;
107 link->rf_tech = rf_tech;
108 link->mode = mode;
109
110 mutex_unlock(&link->lock);
111}
112
113static void nfcsim_link_recv_cancel(struct nfcsim_link *link)
114{
115 mutex_lock(&link->lock);
116
117 link->mode = NFCSIM_MODE_NONE;
118
119 mutex_unlock(&link->lock);
120
121 nfcsim_link_recv_wake(link);
122}
123
124static void nfcsim_link_shutdown(struct nfcsim_link *link)
125{
126 mutex_lock(&link->lock);
127
128 link->shutdown = 1;
129 link->mode = NFCSIM_MODE_NONE;
130
131 mutex_unlock(&link->lock);
132
133 nfcsim_link_recv_wake(link);
134}
135
136static struct sk_buff *nfcsim_link_recv_skb(struct nfcsim_link *link,
137 int timeout, u8 rf_tech, u8 mode)
138{
139 int rc;
140 struct sk_buff *skb;
141
142 rc = wait_event_interruptible_timeout(link->recv_wait,
143 link->cond,
144 msecs_to_jiffies(timeout));
145
146 mutex_lock(&link->lock);
147
148 skb = link->skb;
149 link->skb = NULL;
150
151 if (!rc) {
152 rc = -ETIMEDOUT;
153 goto done;
154 }
155
156 if (!skb || link->rf_tech != rf_tech || link->mode == mode) {
157 rc = -EINVAL;
158 goto done;
159 }
160
161 if (link->shutdown) {
162 rc = -ENODEV;
163 goto done;
164 }
165
166done:
167 mutex_unlock(&link->lock);
168
169 if (rc < 0) {
170 dev_kfree_skb(skb);
171 skb = ERR_PTR(rc);
172 }
173
174 link->cond = 0;
175
176 return skb;
177}
178
179static void nfcsim_send_wq(struct work_struct *work)
180{
181 struct nfcsim *dev = container_of(work, struct nfcsim, send_work.work);
182
183 /*
184 * To effectively send data, the device just wake up its link_out which
185 * is the link_in of the peer device. The exchanged skb has already been
186 * stored in the dev->link_out through nfcsim_link_set_skb().
187 */
188 nfcsim_link_recv_wake(dev->link_out);
189}
190
191static void nfcsim_recv_wq(struct work_struct *work)
192{
193 struct nfcsim *dev = container_of(work, struct nfcsim, recv_work);
194 struct sk_buff *skb;
195
196 skb = nfcsim_link_recv_skb(dev->link_in, dev->recv_timeout,
197 dev->rf_tech, dev->mode);
198
199 if (!dev->up) {
200 NFCSIM_ERR(dev, "Device is down\n");
201
202 if (!IS_ERR(skb))
203 dev_kfree_skb(skb);
204
205 skb = ERR_PTR(-ENODEV);
206 }
207
208 dev->cb(dev->nfc_digital_dev, dev->arg, skb);
209}
210
211static int nfcsim_send(struct nfc_digital_dev *ddev, struct sk_buff *skb,
212 u16 timeout, nfc_digital_cmd_complete_t cb, void *arg)
213{
214 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
215 u8 delay;
216
217 if (!dev->up) {
218 NFCSIM_ERR(dev, "Device is down\n");
219 return -ENODEV;
220 }
221
222 dev->recv_timeout = timeout;
223 dev->cb = cb;
224 dev->arg = arg;
225
226 schedule_work(&dev->recv_work);
227
228 if (dev->dropframe) {
229 NFCSIM_DBG(dev, "dropping frame (out of %d)\n", dev->dropframe);
230 dev_kfree_skb(skb);
231 dev->dropframe--;
232
233 return 0;
234 }
235
236 if (skb) {
237 nfcsim_link_set_skb(dev->link_out, skb, dev->rf_tech,
238 dev->mode);
239
240 /* Add random delay (between 3 and 10 ms) before sending data */
241 get_random_bytes(&delay, 1);
242 delay = 3 + (delay & 0x07);
243
244 schedule_delayed_work(&dev->send_work, msecs_to_jiffies(delay));
245 }
246
247 return 0;
248}
249
250static void nfcsim_abort_cmd(struct nfc_digital_dev *ddev)
251{
252 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
253
254 nfcsim_link_recv_cancel(dev->link_in);
255}
256
257static int nfcsim_switch_rf(struct nfc_digital_dev *ddev, bool on)
258{
259 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
260
261 dev->up = on;
262
263 return 0;
264}
265
266static int nfcsim_in_configure_hw(struct nfc_digital_dev *ddev,
267 int type, int param)
268{
269 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
270
271 switch (type) {
272 case NFC_DIGITAL_CONFIG_RF_TECH:
273 dev->up = true;
274 dev->mode = NFCSIM_MODE_INITIATOR;
275 dev->rf_tech = param;
276 break;
277
278 case NFC_DIGITAL_CONFIG_FRAMING:
279 break;
280
281 default:
282 NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
283 return -EINVAL;
284 }
285
286 return 0;
287}
288
289static int nfcsim_in_send_cmd(struct nfc_digital_dev *ddev,
290 struct sk_buff *skb, u16 timeout,
291 nfc_digital_cmd_complete_t cb, void *arg)
292{
293 return nfcsim_send(ddev, skb, timeout, cb, arg);
294}
295
296static int nfcsim_tg_configure_hw(struct nfc_digital_dev *ddev,
297 int type, int param)
298{
299 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
300
301 switch (type) {
302 case NFC_DIGITAL_CONFIG_RF_TECH:
303 dev->up = true;
304 dev->mode = NFCSIM_MODE_TARGET;
305 dev->rf_tech = param;
306 break;
307
308 case NFC_DIGITAL_CONFIG_FRAMING:
309 break;
310
311 default:
312 NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
313 return -EINVAL;
314 }
315
316 return 0;
317}
318
319static int nfcsim_tg_send_cmd(struct nfc_digital_dev *ddev,
320 struct sk_buff *skb, u16 timeout,
321 nfc_digital_cmd_complete_t cb, void *arg)
322{
323 return nfcsim_send(ddev, skb, timeout, cb, arg);
324}
325
326static int nfcsim_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
327 nfc_digital_cmd_complete_t cb, void *arg)
328{
329 return nfcsim_send(ddev, NULL, timeout, cb, arg);
330}
331
332static struct nfc_digital_ops nfcsim_digital_ops = {
333 .in_configure_hw = nfcsim_in_configure_hw,
334 .in_send_cmd = nfcsim_in_send_cmd,
335
336 .tg_listen = nfcsim_tg_listen,
337 .tg_configure_hw = nfcsim_tg_configure_hw,
338 .tg_send_cmd = nfcsim_tg_send_cmd,
339
340 .abort_cmd = nfcsim_abort_cmd,
341 .switch_rf = nfcsim_switch_rf,
342};
343
344static struct dentry *nfcsim_debugfs_root;
345
346static void nfcsim_debugfs_init(void)
347{
348 nfcsim_debugfs_root = debugfs_create_dir("nfcsim", NULL);
349
350 if (!nfcsim_debugfs_root)
351 pr_err("Could not create debugfs entry\n");
352
353}
354
355static void nfcsim_debugfs_remove(void)
356{
357 debugfs_remove_recursive(nfcsim_debugfs_root);
358}
359
360static void nfcsim_debugfs_init_dev(struct nfcsim *dev)
361{
362 struct dentry *dev_dir;
363 char devname[5]; /* nfcX\0 */
364 u32 idx;
365 int n;
366
367 if (!nfcsim_debugfs_root) {
368 NFCSIM_ERR(dev, "nfcsim debugfs not initialized\n");
369 return;
370 }
371
372 idx = dev->nfc_digital_dev->nfc_dev->idx;
373 n = snprintf(devname, sizeof(devname), "nfc%d", idx);
374 if (n >= sizeof(devname)) {
375 NFCSIM_ERR(dev, "Could not compute dev name for dev %d\n", idx);
376 return;
377 }
378
379 dev_dir = debugfs_create_dir(devname, nfcsim_debugfs_root);
380 if (!dev_dir) {
381 NFCSIM_ERR(dev, "Could not create debugfs entries for nfc%d\n",
382 idx);
383 return;
384 }
385
386 debugfs_create_u8("dropframe", 0664, dev_dir, &dev->dropframe);
387}
388
389static struct nfcsim *nfcsim_device_new(struct nfcsim_link *link_in,
390 struct nfcsim_link *link_out)
391{
392 struct nfcsim *dev;
393 int rc;
394
395 dev = kzalloc(sizeof(struct nfcsim), GFP_KERNEL);
396 if (!dev)
397 return ERR_PTR(-ENOMEM);
398
399 INIT_DELAYED_WORK(&dev->send_work, nfcsim_send_wq);
400 INIT_WORK(&dev->recv_work, nfcsim_recv_wq);
401
402 dev->nfc_digital_dev =
403 nfc_digital_allocate_device(&nfcsim_digital_ops,
404 NFC_PROTO_NFC_DEP_MASK,
405 NFCSIM_CAPABILITIES,
406 0, 0);
407 if (!dev->nfc_digital_dev) {
408 kfree(dev);
409 return ERR_PTR(-ENOMEM);
410 }
411
412 nfc_digital_set_drvdata(dev->nfc_digital_dev, dev);
413
414 dev->link_in = link_in;
415 dev->link_out = link_out;
416
417 rc = nfc_digital_register_device(dev->nfc_digital_dev);
418 if (rc) {
419 pr_err("Could not register digital device (%d)\n", rc);
420 nfc_digital_free_device(dev->nfc_digital_dev);
421 kfree(dev);
422
423 return ERR_PTR(rc);
424 }
425
426 nfcsim_debugfs_init_dev(dev);
427
428 return dev;
429}
430
431static void nfcsim_device_free(struct nfcsim *dev)
432{
433 nfc_digital_unregister_device(dev->nfc_digital_dev);
434
435 dev->up = false;
436
437 nfcsim_link_shutdown(dev->link_in);
438
439 cancel_delayed_work_sync(&dev->send_work);
440 cancel_work_sync(&dev->recv_work);
441
442 nfc_digital_free_device(dev->nfc_digital_dev);
443
444 kfree(dev);
445}
446
447static struct nfcsim *dev0;
448static struct nfcsim *dev1;
449
450static int __init nfcsim_init(void)
451{
452 struct nfcsim_link *link0, *link1;
453 int rc;
454
455 link0 = nfcsim_link_new();
456 link1 = nfcsim_link_new();
457 if (!link0 || !link1) {
458 rc = -ENOMEM;
459 goto exit_err;
460 }
461
462 nfcsim_debugfs_init();
463
464 dev0 = nfcsim_device_new(link0, link1);
465 if (IS_ERR(dev0)) {
466 rc = PTR_ERR(dev0);
467 goto exit_err;
468 }
469
470 dev1 = nfcsim_device_new(link1, link0);
471 if (IS_ERR(dev1)) {
472 nfcsim_device_free(dev0);
473
474 rc = PTR_ERR(dev1);
475 goto exit_err;
476 }
477
478 pr_info("nfcsim " NFCSIM_VERSION " initialized\n");
479
480 return 0;
481
482exit_err:
483 pr_err("Failed to initialize nfcsim driver (%d)\n", rc);
484
485 if (link0)
486 nfcsim_link_free(link0);
487 if (link1)
488 nfcsim_link_free(link1);
489
490 return rc;
491}
492
493static void __exit nfcsim_exit(void)
494{
495 struct nfcsim_link *link0, *link1;
496
497 link0 = dev0->link_in;
498 link1 = dev0->link_out;
499
500 nfcsim_device_free(dev0);
501 nfcsim_device_free(dev1);
502
503 nfcsim_link_free(link0);
504 nfcsim_link_free(link1);
505
506 nfcsim_debugfs_remove();
507}
508
509module_init(nfcsim_init);
510module_exit(nfcsim_exit);
511
512MODULE_DESCRIPTION("NFCSim driver ver " NFCSIM_VERSION);
513MODULE_VERSION(NFCSIM_VERSION);
514MODULE_LICENSE("GPL");
515