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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * NFC hardware simulation driver
4 * Copyright (c) 2013, Intel Corporation.
5 */
6
7#include <linux/device.h>
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/ctype.h>
11#include <linux/debugfs.h>
12#include <linux/nfc.h>
13#include <net/nfc/nfc.h>
14#include <net/nfc/digital.h>
15
16#define NFCSIM_ERR(d, fmt, args...) nfc_err(&d->nfc_digital_dev->nfc_dev->dev, \
17 "%s: " fmt, __func__, ## args)
18
19#define NFCSIM_DBG(d, fmt, args...) dev_dbg(&d->nfc_digital_dev->nfc_dev->dev, \
20 "%s: " fmt, __func__, ## args)
21
22#define NFCSIM_VERSION "0.2"
23
24#define NFCSIM_MODE_NONE 0
25#define NFCSIM_MODE_INITIATOR 1
26#define NFCSIM_MODE_TARGET 2
27
28#define NFCSIM_CAPABILITIES (NFC_DIGITAL_DRV_CAPS_IN_CRC | \
29 NFC_DIGITAL_DRV_CAPS_TG_CRC)
30
31struct nfcsim {
32 struct nfc_digital_dev *nfc_digital_dev;
33
34 struct work_struct recv_work;
35 struct delayed_work send_work;
36
37 struct nfcsim_link *link_in;
38 struct nfcsim_link *link_out;
39
40 bool up;
41 u8 mode;
42 u8 rf_tech;
43
44 u16 recv_timeout;
45
46 nfc_digital_cmd_complete_t cb;
47 void *arg;
48
49 u8 dropframe;
50};
51
52struct nfcsim_link {
53 struct mutex lock;
54
55 u8 rf_tech;
56 u8 mode;
57
58 u8 shutdown;
59
60 struct sk_buff *skb;
61 wait_queue_head_t recv_wait;
62 u8 cond;
63};
64
65static struct nfcsim_link *nfcsim_link_new(void)
66{
67 struct nfcsim_link *link;
68
69 link = kzalloc(sizeof(struct nfcsim_link), GFP_KERNEL);
70 if (!link)
71 return NULL;
72
73 mutex_init(&link->lock);
74 init_waitqueue_head(&link->recv_wait);
75
76 return link;
77}
78
79static void nfcsim_link_free(struct nfcsim_link *link)
80{
81 dev_kfree_skb(link->skb);
82 kfree(link);
83}
84
85static void nfcsim_link_recv_wake(struct nfcsim_link *link)
86{
87 link->cond = 1;
88 wake_up_interruptible(&link->recv_wait);
89}
90
91static void nfcsim_link_set_skb(struct nfcsim_link *link, struct sk_buff *skb,
92 u8 rf_tech, u8 mode)
93{
94 mutex_lock(&link->lock);
95
96 dev_kfree_skb(link->skb);
97 link->skb = skb;
98 link->rf_tech = rf_tech;
99 link->mode = mode;
100
101 mutex_unlock(&link->lock);
102}
103
104static void nfcsim_link_recv_cancel(struct nfcsim_link *link)
105{
106 mutex_lock(&link->lock);
107
108 link->mode = NFCSIM_MODE_NONE;
109
110 mutex_unlock(&link->lock);
111
112 nfcsim_link_recv_wake(link);
113}
114
115static void nfcsim_link_shutdown(struct nfcsim_link *link)
116{
117 mutex_lock(&link->lock);
118
119 link->shutdown = 1;
120 link->mode = NFCSIM_MODE_NONE;
121
122 mutex_unlock(&link->lock);
123
124 nfcsim_link_recv_wake(link);
125}
126
127static struct sk_buff *nfcsim_link_recv_skb(struct nfcsim_link *link,
128 int timeout, u8 rf_tech, u8 mode)
129{
130 int rc;
131 struct sk_buff *skb;
132
133 rc = wait_event_interruptible_timeout(link->recv_wait,
134 link->cond,
135 msecs_to_jiffies(timeout));
136
137 mutex_lock(&link->lock);
138
139 skb = link->skb;
140 link->skb = NULL;
141
142 if (!rc) {
143 rc = -ETIMEDOUT;
144 goto done;
145 }
146
147 if (!skb || link->rf_tech != rf_tech || link->mode == mode) {
148 rc = -EINVAL;
149 goto done;
150 }
151
152 if (link->shutdown) {
153 rc = -ENODEV;
154 goto done;
155 }
156
157done:
158 mutex_unlock(&link->lock);
159
160 if (rc < 0) {
161 dev_kfree_skb(skb);
162 skb = ERR_PTR(rc);
163 }
164
165 link->cond = 0;
166
167 return skb;
168}
169
170static void nfcsim_send_wq(struct work_struct *work)
171{
172 struct nfcsim *dev = container_of(work, struct nfcsim, send_work.work);
173
174 /*
175 * To effectively send data, the device just wake up its link_out which
176 * is the link_in of the peer device. The exchanged skb has already been
177 * stored in the dev->link_out through nfcsim_link_set_skb().
178 */
179 nfcsim_link_recv_wake(dev->link_out);
180}
181
182static void nfcsim_recv_wq(struct work_struct *work)
183{
184 struct nfcsim *dev = container_of(work, struct nfcsim, recv_work);
185 struct sk_buff *skb;
186
187 skb = nfcsim_link_recv_skb(dev->link_in, dev->recv_timeout,
188 dev->rf_tech, dev->mode);
189
190 if (!dev->up) {
191 NFCSIM_ERR(dev, "Device is down\n");
192
193 if (!IS_ERR(skb))
194 dev_kfree_skb(skb);
195 return;
196 }
197
198 dev->cb(dev->nfc_digital_dev, dev->arg, skb);
199}
200
201static int nfcsim_send(struct nfc_digital_dev *ddev, struct sk_buff *skb,
202 u16 timeout, nfc_digital_cmd_complete_t cb, void *arg)
203{
204 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
205 u8 delay;
206
207 if (!dev->up) {
208 NFCSIM_ERR(dev, "Device is down\n");
209 return -ENODEV;
210 }
211
212 dev->recv_timeout = timeout;
213 dev->cb = cb;
214 dev->arg = arg;
215
216 schedule_work(&dev->recv_work);
217
218 if (dev->dropframe) {
219 NFCSIM_DBG(dev, "dropping frame (out of %d)\n", dev->dropframe);
220 dev_kfree_skb(skb);
221 dev->dropframe--;
222
223 return 0;
224 }
225
226 if (skb) {
227 nfcsim_link_set_skb(dev->link_out, skb, dev->rf_tech,
228 dev->mode);
229
230 /* Add random delay (between 3 and 10 ms) before sending data */
231 get_random_bytes(&delay, 1);
232 delay = 3 + (delay & 0x07);
233
234 schedule_delayed_work(&dev->send_work, msecs_to_jiffies(delay));
235 }
236
237 return 0;
238}
239
240static void nfcsim_abort_cmd(struct nfc_digital_dev *ddev)
241{
242 const struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
243
244 nfcsim_link_recv_cancel(dev->link_in);
245}
246
247static int nfcsim_switch_rf(struct nfc_digital_dev *ddev, bool on)
248{
249 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
250
251 dev->up = on;
252
253 return 0;
254}
255
256static int nfcsim_in_configure_hw(struct nfc_digital_dev *ddev,
257 int type, int param)
258{
259 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
260
261 switch (type) {
262 case NFC_DIGITAL_CONFIG_RF_TECH:
263 dev->up = true;
264 dev->mode = NFCSIM_MODE_INITIATOR;
265 dev->rf_tech = param;
266 break;
267
268 case NFC_DIGITAL_CONFIG_FRAMING:
269 break;
270
271 default:
272 NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
273 return -EINVAL;
274 }
275
276 return 0;
277}
278
279static int nfcsim_in_send_cmd(struct nfc_digital_dev *ddev,
280 struct sk_buff *skb, u16 timeout,
281 nfc_digital_cmd_complete_t cb, void *arg)
282{
283 return nfcsim_send(ddev, skb, timeout, cb, arg);
284}
285
286static int nfcsim_tg_configure_hw(struct nfc_digital_dev *ddev,
287 int type, int param)
288{
289 struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
290
291 switch (type) {
292 case NFC_DIGITAL_CONFIG_RF_TECH:
293 dev->up = true;
294 dev->mode = NFCSIM_MODE_TARGET;
295 dev->rf_tech = param;
296 break;
297
298 case NFC_DIGITAL_CONFIG_FRAMING:
299 break;
300
301 default:
302 NFCSIM_ERR(dev, "Invalid configuration type: %d\n", type);
303 return -EINVAL;
304 }
305
306 return 0;
307}
308
309static int nfcsim_tg_send_cmd(struct nfc_digital_dev *ddev,
310 struct sk_buff *skb, u16 timeout,
311 nfc_digital_cmd_complete_t cb, void *arg)
312{
313 return nfcsim_send(ddev, skb, timeout, cb, arg);
314}
315
316static int nfcsim_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
317 nfc_digital_cmd_complete_t cb, void *arg)
318{
319 return nfcsim_send(ddev, NULL, timeout, cb, arg);
320}
321
322static const struct nfc_digital_ops nfcsim_digital_ops = {
323 .in_configure_hw = nfcsim_in_configure_hw,
324 .in_send_cmd = nfcsim_in_send_cmd,
325
326 .tg_listen = nfcsim_tg_listen,
327 .tg_configure_hw = nfcsim_tg_configure_hw,
328 .tg_send_cmd = nfcsim_tg_send_cmd,
329
330 .abort_cmd = nfcsim_abort_cmd,
331 .switch_rf = nfcsim_switch_rf,
332};
333
334static struct dentry *nfcsim_debugfs_root;
335
336static void nfcsim_debugfs_init(void)
337{
338 nfcsim_debugfs_root = debugfs_create_dir("nfcsim", NULL);
339}
340
341static void nfcsim_debugfs_remove(void)
342{
343 debugfs_remove_recursive(nfcsim_debugfs_root);
344}
345
346static void nfcsim_debugfs_init_dev(struct nfcsim *dev)
347{
348 struct dentry *dev_dir;
349 char devname[5]; /* nfcX\0 */
350 u32 idx;
351 int n;
352
353 if (!nfcsim_debugfs_root) {
354 NFCSIM_ERR(dev, "nfcsim debugfs not initialized\n");
355 return;
356 }
357
358 idx = dev->nfc_digital_dev->nfc_dev->idx;
359 n = snprintf(devname, sizeof(devname), "nfc%d", idx);
360 if (n >= sizeof(devname)) {
361 NFCSIM_ERR(dev, "Could not compute dev name for dev %d\n", idx);
362 return;
363 }
364
365 dev_dir = debugfs_create_dir(devname, nfcsim_debugfs_root);
366
367 debugfs_create_u8("dropframe", 0664, dev_dir, &dev->dropframe);
368}
369
370static struct nfcsim *nfcsim_device_new(struct nfcsim_link *link_in,
371 struct nfcsim_link *link_out)
372{
373 struct nfcsim *dev;
374 int rc;
375
376 dev = kzalloc(sizeof(struct nfcsim), GFP_KERNEL);
377 if (!dev)
378 return ERR_PTR(-ENOMEM);
379
380 INIT_DELAYED_WORK(&dev->send_work, nfcsim_send_wq);
381 INIT_WORK(&dev->recv_work, nfcsim_recv_wq);
382
383 dev->nfc_digital_dev =
384 nfc_digital_allocate_device(&nfcsim_digital_ops,
385 NFC_PROTO_NFC_DEP_MASK,
386 NFCSIM_CAPABILITIES,
387 0, 0);
388 if (!dev->nfc_digital_dev) {
389 kfree(dev);
390 return ERR_PTR(-ENOMEM);
391 }
392
393 nfc_digital_set_drvdata(dev->nfc_digital_dev, dev);
394
395 dev->link_in = link_in;
396 dev->link_out = link_out;
397
398 rc = nfc_digital_register_device(dev->nfc_digital_dev);
399 if (rc) {
400 pr_err("Could not register digital device (%d)\n", rc);
401 nfc_digital_free_device(dev->nfc_digital_dev);
402 kfree(dev);
403
404 return ERR_PTR(rc);
405 }
406
407 nfcsim_debugfs_init_dev(dev);
408
409 return dev;
410}
411
412static void nfcsim_device_free(struct nfcsim *dev)
413{
414 nfc_digital_unregister_device(dev->nfc_digital_dev);
415
416 dev->up = false;
417
418 nfcsim_link_shutdown(dev->link_in);
419
420 cancel_delayed_work_sync(&dev->send_work);
421 cancel_work_sync(&dev->recv_work);
422
423 nfc_digital_free_device(dev->nfc_digital_dev);
424
425 kfree(dev);
426}
427
428static struct nfcsim *dev0;
429static struct nfcsim *dev1;
430
431static int __init nfcsim_init(void)
432{
433 struct nfcsim_link *link0, *link1;
434 int rc;
435
436 link0 = nfcsim_link_new();
437 link1 = nfcsim_link_new();
438 if (!link0 || !link1) {
439 rc = -ENOMEM;
440 goto exit_err;
441 }
442
443 nfcsim_debugfs_init();
444
445 dev0 = nfcsim_device_new(link0, link1);
446 if (IS_ERR(dev0)) {
447 rc = PTR_ERR(dev0);
448 goto exit_err;
449 }
450
451 dev1 = nfcsim_device_new(link1, link0);
452 if (IS_ERR(dev1)) {
453 nfcsim_device_free(dev0);
454
455 rc = PTR_ERR(dev1);
456 goto exit_err;
457 }
458
459 pr_info("nfcsim " NFCSIM_VERSION " initialized\n");
460
461 return 0;
462
463exit_err:
464 pr_err("Failed to initialize nfcsim driver (%d)\n", rc);
465
466 if (link0)
467 nfcsim_link_free(link0);
468 if (link1)
469 nfcsim_link_free(link1);
470
471 return rc;
472}
473
474static void __exit nfcsim_exit(void)
475{
476 struct nfcsim_link *link0, *link1;
477
478 link0 = dev0->link_in;
479 link1 = dev0->link_out;
480
481 nfcsim_device_free(dev0);
482 nfcsim_device_free(dev1);
483
484 nfcsim_link_free(link0);
485 nfcsim_link_free(link1);
486
487 nfcsim_debugfs_remove();
488}
489
490module_init(nfcsim_init);
491module_exit(nfcsim_exit);
492
493MODULE_DESCRIPTION("NFCSim driver ver " NFCSIM_VERSION);
494MODULE_VERSION(NFCSIM_VERSION);
495MODULE_LICENSE("GPL");
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/nfc.h>
20#include <net/nfc/nfc.h>
21
22#define DEV_ERR(_dev, fmt, args...) nfc_err(&_dev->nfc_dev->dev, \
23 "%s: " fmt, __func__, ## args)
24
25#define DEV_DBG(_dev, fmt, args...) dev_dbg(&_dev->nfc_dev->dev, \
26 "%s: " fmt, __func__, ## args)
27
28#define NFCSIM_VERSION "0.1"
29
30#define NFCSIM_POLL_NONE 0
31#define NFCSIM_POLL_INITIATOR 1
32#define NFCSIM_POLL_TARGET 2
33#define NFCSIM_POLL_DUAL (NFCSIM_POLL_INITIATOR | NFCSIM_POLL_TARGET)
34
35#define RX_DEFAULT_DELAY 5
36
37struct nfcsim {
38 struct nfc_dev *nfc_dev;
39
40 struct mutex lock;
41
42 struct delayed_work recv_work;
43
44 struct sk_buff *clone_skb;
45
46 struct delayed_work poll_work;
47 u8 polling_mode;
48 u8 curr_polling_mode;
49
50 u8 shutting_down;
51
52 u8 up;
53
54 u8 initiator;
55
56 u32 rx_delay;
57
58 data_exchange_cb_t cb;
59 void *cb_context;
60
61 struct nfcsim *peer_dev;
62};
63
64static struct nfcsim *dev0;
65static struct nfcsim *dev1;
66
67static struct workqueue_struct *wq;
68
69static void nfcsim_cleanup_dev(struct nfcsim *dev, u8 shutdown)
70{
71 DEV_DBG(dev, "shutdown=%d\n", shutdown);
72
73 mutex_lock(&dev->lock);
74
75 dev->polling_mode = NFCSIM_POLL_NONE;
76 dev->shutting_down = shutdown;
77 dev->cb = NULL;
78 dev_kfree_skb(dev->clone_skb);
79 dev->clone_skb = NULL;
80
81 mutex_unlock(&dev->lock);
82
83 cancel_delayed_work_sync(&dev->poll_work);
84 cancel_delayed_work_sync(&dev->recv_work);
85}
86
87static int nfcsim_target_found(struct nfcsim *dev)
88{
89 struct nfc_target nfc_tgt;
90
91 DEV_DBG(dev, "\n");
92
93 memset(&nfc_tgt, 0, sizeof(struct nfc_target));
94
95 nfc_tgt.supported_protocols = NFC_PROTO_NFC_DEP_MASK;
96 nfc_targets_found(dev->nfc_dev, &nfc_tgt, 1);
97
98 return 0;
99}
100
101static int nfcsim_dev_up(struct nfc_dev *nfc_dev)
102{
103 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
104
105 DEV_DBG(dev, "\n");
106
107 mutex_lock(&dev->lock);
108
109 dev->up = 1;
110
111 mutex_unlock(&dev->lock);
112
113 return 0;
114}
115
116static int nfcsim_dev_down(struct nfc_dev *nfc_dev)
117{
118 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
119
120 DEV_DBG(dev, "\n");
121
122 mutex_lock(&dev->lock);
123
124 dev->up = 0;
125
126 mutex_unlock(&dev->lock);
127
128 return 0;
129}
130
131static int nfcsim_dep_link_up(struct nfc_dev *nfc_dev,
132 struct nfc_target *target,
133 u8 comm_mode, u8 *gb, size_t gb_len)
134{
135 int rc;
136 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
137 struct nfcsim *peer = dev->peer_dev;
138 u8 *remote_gb;
139 size_t remote_gb_len;
140
141 DEV_DBG(dev, "target_idx: %d, comm_mode: %d\n", target->idx, comm_mode);
142
143 mutex_lock(&peer->lock);
144
145 nfc_tm_activated(peer->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
146 NFC_COMM_ACTIVE, gb, gb_len);
147
148 remote_gb = nfc_get_local_general_bytes(peer->nfc_dev, &remote_gb_len);
149 if (!remote_gb) {
150 DEV_ERR(peer, "Can't get remote general bytes\n");
151
152 mutex_unlock(&peer->lock);
153 return -EINVAL;
154 }
155
156 mutex_unlock(&peer->lock);
157
158 mutex_lock(&dev->lock);
159
160 rc = nfc_set_remote_general_bytes(nfc_dev, remote_gb, remote_gb_len);
161 if (rc) {
162 DEV_ERR(dev, "Can't set remote general bytes\n");
163 mutex_unlock(&dev->lock);
164 return rc;
165 }
166
167 rc = nfc_dep_link_is_up(nfc_dev, target->idx, NFC_COMM_ACTIVE,
168 NFC_RF_INITIATOR);
169
170 mutex_unlock(&dev->lock);
171
172 return rc;
173}
174
175static int nfcsim_dep_link_down(struct nfc_dev *nfc_dev)
176{
177 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
178
179 DEV_DBG(dev, "\n");
180
181 nfcsim_cleanup_dev(dev, 0);
182
183 return 0;
184}
185
186static int nfcsim_start_poll(struct nfc_dev *nfc_dev,
187 u32 im_protocols, u32 tm_protocols)
188{
189 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
190 int rc;
191
192 mutex_lock(&dev->lock);
193
194 if (dev->polling_mode != NFCSIM_POLL_NONE) {
195 DEV_ERR(dev, "Already in polling mode\n");
196 rc = -EBUSY;
197 goto exit;
198 }
199
200 if (im_protocols & NFC_PROTO_NFC_DEP_MASK)
201 dev->polling_mode |= NFCSIM_POLL_INITIATOR;
202
203 if (tm_protocols & NFC_PROTO_NFC_DEP_MASK)
204 dev->polling_mode |= NFCSIM_POLL_TARGET;
205
206 if (dev->polling_mode == NFCSIM_POLL_NONE) {
207 DEV_ERR(dev, "Unsupported polling mode\n");
208 rc = -EINVAL;
209 goto exit;
210 }
211
212 dev->initiator = 0;
213 dev->curr_polling_mode = NFCSIM_POLL_NONE;
214
215 queue_delayed_work(wq, &dev->poll_work, 0);
216
217 DEV_DBG(dev, "Start polling: im: 0x%X, tm: 0x%X\n", im_protocols,
218 tm_protocols);
219
220 rc = 0;
221exit:
222 mutex_unlock(&dev->lock);
223
224 return rc;
225}
226
227static void nfcsim_stop_poll(struct nfc_dev *nfc_dev)
228{
229 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
230
231 DEV_DBG(dev, "Stop poll\n");
232
233 mutex_lock(&dev->lock);
234
235 dev->polling_mode = NFCSIM_POLL_NONE;
236
237 mutex_unlock(&dev->lock);
238
239 cancel_delayed_work_sync(&dev->poll_work);
240}
241
242static int nfcsim_activate_target(struct nfc_dev *nfc_dev,
243 struct nfc_target *target, u32 protocol)
244{
245 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
246
247 DEV_DBG(dev, "\n");
248
249 return -ENOTSUPP;
250}
251
252static void nfcsim_deactivate_target(struct nfc_dev *nfc_dev,
253 struct nfc_target *target, u8 mode)
254{
255 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
256
257 DEV_DBG(dev, "\n");
258}
259
260static void nfcsim_wq_recv(struct work_struct *work)
261{
262 struct nfcsim *dev = container_of(work, struct nfcsim,
263 recv_work.work);
264
265 mutex_lock(&dev->lock);
266
267 if (dev->shutting_down || !dev->up || !dev->clone_skb) {
268 dev_kfree_skb(dev->clone_skb);
269 goto exit;
270 }
271
272 if (dev->initiator) {
273 if (!dev->cb) {
274 DEV_ERR(dev, "Null recv callback\n");
275 dev_kfree_skb(dev->clone_skb);
276 goto exit;
277 }
278
279 dev->cb(dev->cb_context, dev->clone_skb, 0);
280 dev->cb = NULL;
281 } else {
282 nfc_tm_data_received(dev->nfc_dev, dev->clone_skb);
283 }
284
285exit:
286 dev->clone_skb = NULL;
287
288 mutex_unlock(&dev->lock);
289}
290
291static int nfcsim_tx(struct nfc_dev *nfc_dev, struct nfc_target *target,
292 struct sk_buff *skb, data_exchange_cb_t cb,
293 void *cb_context)
294{
295 struct nfcsim *dev = nfc_get_drvdata(nfc_dev);
296 struct nfcsim *peer = dev->peer_dev;
297 int err;
298
299 mutex_lock(&dev->lock);
300
301 if (dev->shutting_down || !dev->up) {
302 mutex_unlock(&dev->lock);
303 err = -ENODEV;
304 goto exit;
305 }
306
307 dev->cb = cb;
308 dev->cb_context = cb_context;
309
310 mutex_unlock(&dev->lock);
311
312 mutex_lock(&peer->lock);
313
314 peer->clone_skb = skb_clone(skb, GFP_KERNEL);
315
316 if (!peer->clone_skb) {
317 DEV_ERR(dev, "skb_clone failed\n");
318 mutex_unlock(&peer->lock);
319 err = -ENOMEM;
320 goto exit;
321 }
322
323 /* This simulates an arbitrary transmission delay between the 2 devices.
324 * If packet transmission occurs immediately between them, we have a
325 * non-stop flow of several tens of thousands SYMM packets per second
326 * and a burning cpu.
327 */
328 queue_delayed_work(wq, &peer->recv_work,
329 msecs_to_jiffies(dev->rx_delay));
330
331 mutex_unlock(&peer->lock);
332
333 err = 0;
334exit:
335 dev_kfree_skb(skb);
336
337 return err;
338}
339
340static int nfcsim_im_transceive(struct nfc_dev *nfc_dev,
341 struct nfc_target *target, struct sk_buff *skb,
342 data_exchange_cb_t cb, void *cb_context)
343{
344 return nfcsim_tx(nfc_dev, target, skb, cb, cb_context);
345}
346
347static int nfcsim_tm_send(struct nfc_dev *nfc_dev, struct sk_buff *skb)
348{
349 return nfcsim_tx(nfc_dev, NULL, skb, NULL, NULL);
350}
351
352static struct nfc_ops nfcsim_nfc_ops = {
353 .dev_up = nfcsim_dev_up,
354 .dev_down = nfcsim_dev_down,
355 .dep_link_up = nfcsim_dep_link_up,
356 .dep_link_down = nfcsim_dep_link_down,
357 .start_poll = nfcsim_start_poll,
358 .stop_poll = nfcsim_stop_poll,
359 .activate_target = nfcsim_activate_target,
360 .deactivate_target = nfcsim_deactivate_target,
361 .im_transceive = nfcsim_im_transceive,
362 .tm_send = nfcsim_tm_send,
363};
364
365static void nfcsim_set_polling_mode(struct nfcsim *dev)
366{
367 if (dev->polling_mode == NFCSIM_POLL_NONE) {
368 dev->curr_polling_mode = NFCSIM_POLL_NONE;
369 return;
370 }
371
372 if (dev->curr_polling_mode == NFCSIM_POLL_NONE) {
373 if (dev->polling_mode & NFCSIM_POLL_INITIATOR)
374 dev->curr_polling_mode = NFCSIM_POLL_INITIATOR;
375 else
376 dev->curr_polling_mode = NFCSIM_POLL_TARGET;
377
378 return;
379 }
380
381 if (dev->polling_mode == NFCSIM_POLL_DUAL) {
382 if (dev->curr_polling_mode == NFCSIM_POLL_TARGET)
383 dev->curr_polling_mode = NFCSIM_POLL_INITIATOR;
384 else
385 dev->curr_polling_mode = NFCSIM_POLL_TARGET;
386 }
387}
388
389static void nfcsim_wq_poll(struct work_struct *work)
390{
391 struct nfcsim *dev = container_of(work, struct nfcsim, poll_work.work);
392 struct nfcsim *peer = dev->peer_dev;
393
394 /* These work items run on an ordered workqueue and are therefore
395 * serialized. So we can take both mutexes without being dead locked.
396 */
397 mutex_lock(&dev->lock);
398 mutex_lock(&peer->lock);
399
400 nfcsim_set_polling_mode(dev);
401
402 if (dev->curr_polling_mode == NFCSIM_POLL_NONE) {
403 DEV_DBG(dev, "Not polling\n");
404 goto unlock;
405 }
406
407 DEV_DBG(dev, "Polling as %s",
408 dev->curr_polling_mode == NFCSIM_POLL_INITIATOR ?
409 "initiator\n" : "target\n");
410
411 if (dev->curr_polling_mode == NFCSIM_POLL_TARGET)
412 goto sched_work;
413
414 if (peer->curr_polling_mode == NFCSIM_POLL_TARGET) {
415 peer->polling_mode = NFCSIM_POLL_NONE;
416 dev->polling_mode = NFCSIM_POLL_NONE;
417
418 dev->initiator = 1;
419
420 nfcsim_target_found(dev);
421
422 goto unlock;
423 }
424
425sched_work:
426 /* This defines the delay for an initiator to check if the other device
427 * is polling in target mode.
428 * If the device starts in dual mode polling, it switches between
429 * initiator and target at every round.
430 * Because the wq is ordered and only 1 work item is executed at a time,
431 * we'll always have one device polling as initiator and the other as
432 * target at some point, even if both are started in dual mode.
433 */
434 queue_delayed_work(wq, &dev->poll_work, msecs_to_jiffies(200));
435
436unlock:
437 mutex_unlock(&peer->lock);
438 mutex_unlock(&dev->lock);
439}
440
441static struct nfcsim *nfcsim_init_dev(void)
442{
443 struct nfcsim *dev;
444 int rc = -ENOMEM;
445
446 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
447 if (dev == NULL)
448 return ERR_PTR(-ENOMEM);
449
450 mutex_init(&dev->lock);
451
452 INIT_DELAYED_WORK(&dev->recv_work, nfcsim_wq_recv);
453 INIT_DELAYED_WORK(&dev->poll_work, nfcsim_wq_poll);
454
455 dev->nfc_dev = nfc_allocate_device(&nfcsim_nfc_ops,
456 NFC_PROTO_NFC_DEP_MASK,
457 0, 0);
458 if (!dev->nfc_dev)
459 goto error;
460
461 nfc_set_drvdata(dev->nfc_dev, dev);
462
463 rc = nfc_register_device(dev->nfc_dev);
464 if (rc)
465 goto free_nfc_dev;
466
467 dev->rx_delay = RX_DEFAULT_DELAY;
468 return dev;
469
470free_nfc_dev:
471 nfc_free_device(dev->nfc_dev);
472
473error:
474 kfree(dev);
475
476 return ERR_PTR(rc);
477}
478
479static void nfcsim_free_device(struct nfcsim *dev)
480{
481 nfc_unregister_device(dev->nfc_dev);
482
483 nfc_free_device(dev->nfc_dev);
484
485 kfree(dev);
486}
487
488static int __init nfcsim_init(void)
489{
490 int rc;
491
492 /* We need an ordered wq to ensure that poll_work items are executed
493 * one at a time.
494 */
495 wq = alloc_ordered_workqueue("nfcsim", 0);
496 if (!wq) {
497 rc = -ENOMEM;
498 goto exit;
499 }
500
501 dev0 = nfcsim_init_dev();
502 if (IS_ERR(dev0)) {
503 rc = PTR_ERR(dev0);
504 goto exit;
505 }
506
507 dev1 = nfcsim_init_dev();
508 if (IS_ERR(dev1)) {
509 kfree(dev0);
510
511 rc = PTR_ERR(dev1);
512 goto exit;
513 }
514
515 dev0->peer_dev = dev1;
516 dev1->peer_dev = dev0;
517
518 pr_debug("NFCsim " NFCSIM_VERSION " initialized\n");
519
520 rc = 0;
521exit:
522 if (rc)
523 pr_err("Failed to initialize nfcsim driver (%d)\n",
524 rc);
525
526 return rc;
527}
528
529static void __exit nfcsim_exit(void)
530{
531 nfcsim_cleanup_dev(dev0, 1);
532 nfcsim_cleanup_dev(dev1, 1);
533
534 nfcsim_free_device(dev0);
535 nfcsim_free_device(dev1);
536
537 destroy_workqueue(wq);
538}
539
540module_init(nfcsim_init);
541module_exit(nfcsim_exit);
542
543MODULE_DESCRIPTION("NFCSim driver ver " NFCSIM_VERSION);
544MODULE_VERSION(NFCSIM_VERSION);
545MODULE_LICENSE("GPL");