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9961127d VC |
1 | /* |
2 | * Copyright (C) 2015, Marvell International Ltd. | |
3 | * | |
4 | * This software file (the "File") is distributed by Marvell International | |
5 | * Ltd. under the terms of the GNU General Public License Version 2, June 1991 | |
6 | * (the "License"). You may use, redistribute and/or modify this File in | |
7 | * accordance with the terms and conditions of the License, a copy of which | |
8 | * is available on the worldwide web at | |
9 | * http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt. | |
10 | * | |
11 | * THE FILE IS DISTRIBUTED AS-IS, WITHOUT WARRANTY OF ANY KIND, AND THE | |
12 | * IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE | |
13 | * ARE EXPRESSLY DISCLAIMED. The License provides additional details about | |
14 | * this warranty disclaimer. | |
9961127d VC |
15 | */ |
16 | ||
17 | /* Inspired (hugely) by HCI LDISC implementation in Bluetooth. | |
18 | * | |
19 | * Copyright (C) 2000-2001 Qualcomm Incorporated | |
20 | * Copyright (C) 2002-2003 Maxim Krasnyansky <maxk@qualcomm.com> | |
21 | * Copyright (C) 2004-2005 Marcel Holtmann <marcel@holtmann.org> | |
22 | */ | |
23 | ||
24 | #include <linux/module.h> | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/types.h> | |
29 | #include <linux/fcntl.h> | |
30 | #include <linux/interrupt.h> | |
31 | #include <linux/ptrace.h> | |
32 | #include <linux/poll.h> | |
33 | ||
34 | #include <linux/slab.h> | |
35 | #include <linux/tty.h> | |
36 | #include <linux/errno.h> | |
37 | #include <linux/string.h> | |
38 | #include <linux/signal.h> | |
39 | #include <linux/ioctl.h> | |
40 | #include <linux/skbuff.h> | |
41 | ||
42 | #include <net/nfc/nci.h> | |
43 | #include <net/nfc/nci_core.h> | |
44 | ||
45 | /* TX states */ | |
46 | #define NCI_UART_SENDING 1 | |
47 | #define NCI_UART_TX_WAKEUP 2 | |
48 | ||
49 | static struct nci_uart *nci_uart_drivers[NCI_UART_DRIVER_MAX]; | |
50 | ||
51 | static inline struct sk_buff *nci_uart_dequeue(struct nci_uart *nu) | |
52 | { | |
53 | struct sk_buff *skb = nu->tx_skb; | |
54 | ||
55 | if (!skb) | |
56 | skb = skb_dequeue(&nu->tx_q); | |
57 | else | |
58 | nu->tx_skb = NULL; | |
59 | ||
60 | return skb; | |
61 | } | |
62 | ||
63 | static inline int nci_uart_queue_empty(struct nci_uart *nu) | |
64 | { | |
65 | if (nu->tx_skb) | |
66 | return 0; | |
67 | ||
68 | return skb_queue_empty(&nu->tx_q); | |
69 | } | |
70 | ||
71 | static int nci_uart_tx_wakeup(struct nci_uart *nu) | |
72 | { | |
73 | if (test_and_set_bit(NCI_UART_SENDING, &nu->tx_state)) { | |
74 | set_bit(NCI_UART_TX_WAKEUP, &nu->tx_state); | |
75 | return 0; | |
76 | } | |
77 | ||
78 | schedule_work(&nu->write_work); | |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
83 | static void nci_uart_write_work(struct work_struct *work) | |
84 | { | |
85 | struct nci_uart *nu = container_of(work, struct nci_uart, write_work); | |
86 | struct tty_struct *tty = nu->tty; | |
87 | struct sk_buff *skb; | |
88 | ||
89 | restart: | |
90 | clear_bit(NCI_UART_TX_WAKEUP, &nu->tx_state); | |
91 | ||
92 | if (nu->ops.tx_start) | |
93 | nu->ops.tx_start(nu); | |
94 | ||
95 | while ((skb = nci_uart_dequeue(nu))) { | |
96 | int len; | |
97 | ||
98 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
99 | len = tty->ops->write(tty, skb->data, skb->len); | |
100 | skb_pull(skb, len); | |
101 | if (skb->len) { | |
102 | nu->tx_skb = skb; | |
103 | break; | |
104 | } | |
105 | kfree_skb(skb); | |
106 | } | |
107 | ||
108 | if (test_bit(NCI_UART_TX_WAKEUP, &nu->tx_state)) | |
109 | goto restart; | |
110 | ||
111 | if (nu->ops.tx_done && nci_uart_queue_empty(nu)) | |
112 | nu->ops.tx_done(nu); | |
113 | ||
114 | clear_bit(NCI_UART_SENDING, &nu->tx_state); | |
115 | } | |
116 | ||
117 | static int nci_uart_set_driver(struct tty_struct *tty, unsigned int driver) | |
118 | { | |
119 | struct nci_uart *nu = NULL; | |
120 | int ret; | |
121 | ||
122 | if (driver >= NCI_UART_DRIVER_MAX) | |
123 | return -EINVAL; | |
124 | ||
125 | if (!nci_uart_drivers[driver]) | |
126 | return -ENOENT; | |
127 | ||
128 | nu = kzalloc(sizeof(*nu), GFP_KERNEL); | |
129 | if (!nu) | |
130 | return -ENOMEM; | |
131 | ||
132 | memcpy(nu, nci_uart_drivers[driver], sizeof(struct nci_uart)); | |
133 | nu->tty = tty; | |
134 | tty->disc_data = nu; | |
135 | skb_queue_head_init(&nu->tx_q); | |
136 | INIT_WORK(&nu->write_work, nci_uart_write_work); | |
137 | spin_lock_init(&nu->rx_lock); | |
138 | ||
139 | ret = nu->ops.open(nu); | |
140 | if (ret) { | |
141 | tty->disc_data = NULL; | |
142 | kfree(nu); | |
143 | } else if (!try_module_get(nu->owner)) { | |
144 | nu->ops.close(nu); | |
145 | tty->disc_data = NULL; | |
146 | kfree(nu); | |
147 | return -ENOENT; | |
148 | } | |
149 | return ret; | |
150 | } | |
151 | ||
152 | /* ------ LDISC part ------ */ | |
153 | ||
154 | /* nci_uart_tty_open | |
155 | * | |
156 | * Called when line discipline changed to NCI_UART. | |
157 | * | |
158 | * Arguments: | |
159 | * tty pointer to tty info structure | |
160 | * Return Value: | |
161 | * 0 if success, otherwise error code | |
162 | */ | |
163 | static int nci_uart_tty_open(struct tty_struct *tty) | |
164 | { | |
165 | /* Error if the tty has no write op instead of leaving an exploitable | |
166 | * hole | |
167 | */ | |
168 | if (!tty->ops->write) | |
169 | return -EOPNOTSUPP; | |
170 | ||
171 | tty->disc_data = NULL; | |
172 | tty->receive_room = 65536; | |
173 | ||
582e20a0 | 174 | /* Flush any pending characters in the driver */ |
9961127d VC |
175 | tty_driver_flush_buffer(tty); |
176 | ||
177 | return 0; | |
178 | } | |
179 | ||
180 | /* nci_uart_tty_close() | |
181 | * | |
182 | * Called when the line discipline is changed to something | |
183 | * else, the tty is closed, or the tty detects a hangup. | |
184 | */ | |
185 | static void nci_uart_tty_close(struct tty_struct *tty) | |
186 | { | |
187 | struct nci_uart *nu = (void *)tty->disc_data; | |
188 | ||
189 | /* Detach from the tty */ | |
190 | tty->disc_data = NULL; | |
191 | ||
192 | if (!nu) | |
193 | return; | |
194 | ||
195 | if (nu->tx_skb) | |
196 | kfree_skb(nu->tx_skb); | |
197 | if (nu->rx_skb) | |
198 | kfree_skb(nu->rx_skb); | |
199 | ||
200 | skb_queue_purge(&nu->tx_q); | |
201 | ||
202 | nu->ops.close(nu); | |
203 | nu->tty = NULL; | |
204 | module_put(nu->owner); | |
205 | ||
206 | cancel_work_sync(&nu->write_work); | |
207 | ||
208 | kfree(nu); | |
209 | } | |
210 | ||
211 | /* nci_uart_tty_wakeup() | |
212 | * | |
213 | * Callback for transmit wakeup. Called when low level | |
214 | * device driver can accept more send data. | |
215 | * | |
216 | * Arguments: tty pointer to associated tty instance data | |
217 | * Return Value: None | |
218 | */ | |
219 | static void nci_uart_tty_wakeup(struct tty_struct *tty) | |
220 | { | |
221 | struct nci_uart *nu = (void *)tty->disc_data; | |
222 | ||
223 | if (!nu) | |
224 | return; | |
225 | ||
226 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
227 | ||
228 | if (tty != nu->tty) | |
229 | return; | |
230 | ||
231 | nci_uart_tx_wakeup(nu); | |
232 | } | |
233 | ||
234 | /* nci_uart_tty_receive() | |
235 | * | |
236 | * Called by tty low level driver when receive data is | |
237 | * available. | |
238 | * | |
239 | * Arguments: tty pointer to tty isntance data | |
240 | * data pointer to received data | |
241 | * flags pointer to flags for data | |
242 | * count count of received data in bytes | |
243 | * | |
244 | * Return Value: None | |
245 | */ | |
246 | static void nci_uart_tty_receive(struct tty_struct *tty, const u8 *data, | |
247 | char *flags, int count) | |
248 | { | |
249 | struct nci_uart *nu = (void *)tty->disc_data; | |
250 | ||
251 | if (!nu || tty != nu->tty) | |
252 | return; | |
253 | ||
254 | spin_lock(&nu->rx_lock); | |
255 | nu->ops.recv_buf(nu, (void *)data, flags, count); | |
256 | spin_unlock(&nu->rx_lock); | |
257 | ||
258 | tty_unthrottle(tty); | |
259 | } | |
260 | ||
261 | /* nci_uart_tty_ioctl() | |
262 | * | |
263 | * Process IOCTL system call for the tty device. | |
264 | * | |
265 | * Arguments: | |
266 | * | |
267 | * tty pointer to tty instance data | |
268 | * file pointer to open file object for device | |
269 | * cmd IOCTL command code | |
270 | * arg argument for IOCTL call (cmd dependent) | |
271 | * | |
272 | * Return Value: Command dependent | |
273 | */ | |
274 | static int nci_uart_tty_ioctl(struct tty_struct *tty, struct file *file, | |
275 | unsigned int cmd, unsigned long arg) | |
276 | { | |
277 | struct nci_uart *nu = (void *)tty->disc_data; | |
278 | int err = 0; | |
279 | ||
280 | switch (cmd) { | |
281 | case NCIUARTSETDRIVER: | |
282 | if (!nu) | |
283 | return nci_uart_set_driver(tty, (unsigned int)arg); | |
284 | else | |
285 | return -EBUSY; | |
286 | break; | |
287 | default: | |
288 | err = n_tty_ioctl_helper(tty, file, cmd, arg); | |
289 | break; | |
290 | } | |
291 | ||
292 | return err; | |
293 | } | |
294 | ||
295 | /* We don't provide read/write/poll interface for user space. */ | |
296 | static ssize_t nci_uart_tty_read(struct tty_struct *tty, struct file *file, | |
297 | unsigned char __user *buf, size_t nr) | |
298 | { | |
299 | return 0; | |
300 | } | |
301 | ||
302 | static ssize_t nci_uart_tty_write(struct tty_struct *tty, struct file *file, | |
303 | const unsigned char *data, size_t count) | |
304 | { | |
305 | return 0; | |
306 | } | |
307 | ||
308 | static unsigned int nci_uart_tty_poll(struct tty_struct *tty, | |
309 | struct file *filp, poll_table *wait) | |
310 | { | |
311 | return 0; | |
312 | } | |
313 | ||
314 | static int nci_uart_send(struct nci_uart *nu, struct sk_buff *skb) | |
315 | { | |
316 | /* Queue TX packet */ | |
317 | skb_queue_tail(&nu->tx_q, skb); | |
318 | ||
319 | /* Try to start TX (if possible) */ | |
320 | nci_uart_tx_wakeup(nu); | |
321 | ||
322 | return 0; | |
323 | } | |
324 | ||
325 | /* -- Default recv_buf handler -- | |
326 | * | |
327 | * This handler supposes that NCI frames are sent over UART link without any | |
328 | * framing. It reads NCI header, retrieve the packet size and once all packet | |
329 | * bytes are received it passes it to nci_uart driver for processing. | |
330 | */ | |
331 | static int nci_uart_default_recv_buf(struct nci_uart *nu, const u8 *data, | |
332 | char *flags, int count) | |
333 | { | |
334 | int chunk_len; | |
335 | ||
336 | if (!nu->ndev) { | |
337 | nfc_err(nu->tty->dev, | |
338 | "receive data from tty but no NCI dev is attached yet, drop buffer\n"); | |
339 | return 0; | |
340 | } | |
341 | ||
342 | /* Decode all incoming data in packets | |
343 | * and enqueue then for processing. | |
344 | */ | |
345 | while (count > 0) { | |
346 | /* If this is the first data of a packet, allocate a buffer */ | |
347 | if (!nu->rx_skb) { | |
348 | nu->rx_packet_len = -1; | |
349 | nu->rx_skb = nci_skb_alloc(nu->ndev, | |
350 | NCI_MAX_PACKET_SIZE, | |
351 | GFP_KERNEL); | |
352 | if (!nu->rx_skb) | |
353 | return -ENOMEM; | |
354 | } | |
355 | ||
356 | /* Eat byte after byte till full packet header is received */ | |
357 | if (nu->rx_skb->len < NCI_CTRL_HDR_SIZE) { | |
634fef61 | 358 | skb_put_u8(nu->rx_skb, *data++); |
9961127d VC |
359 | --count; |
360 | continue; | |
361 | } | |
362 | ||
363 | /* Header was received but packet len was not read */ | |
364 | if (nu->rx_packet_len < 0) | |
365 | nu->rx_packet_len = NCI_CTRL_HDR_SIZE + | |
366 | nci_plen(nu->rx_skb->data); | |
367 | ||
368 | /* Compute how many bytes are missing and how many bytes can | |
369 | * be consumed. | |
370 | */ | |
371 | chunk_len = nu->rx_packet_len - nu->rx_skb->len; | |
372 | if (count < chunk_len) | |
373 | chunk_len = count; | |
59ae1d12 | 374 | skb_put_data(nu->rx_skb, data, chunk_len); |
9961127d VC |
375 | data += chunk_len; |
376 | count -= chunk_len; | |
377 | ||
378 | /* Chcek if packet is fully received */ | |
379 | if (nu->rx_packet_len == nu->rx_skb->len) { | |
380 | /* Pass RX packet to driver */ | |
381 | if (nu->ops.recv(nu, nu->rx_skb) != 0) | |
382 | nfc_err(nu->tty->dev, "corrupted RX packet\n"); | |
383 | /* Next packet will be a new one */ | |
384 | nu->rx_skb = NULL; | |
385 | } | |
386 | } | |
387 | ||
388 | return 0; | |
389 | } | |
390 | ||
391 | /* -- Default recv handler -- */ | |
392 | static int nci_uart_default_recv(struct nci_uart *nu, struct sk_buff *skb) | |
393 | { | |
394 | return nci_recv_frame(nu->ndev, skb); | |
395 | } | |
396 | ||
397 | int nci_uart_register(struct nci_uart *nu) | |
398 | { | |
399 | if (!nu || !nu->ops.open || | |
400 | !nu->ops.recv || !nu->ops.close) | |
401 | return -EINVAL; | |
402 | ||
403 | /* Set the send callback */ | |
404 | nu->ops.send = nci_uart_send; | |
405 | ||
406 | /* Install default handlers if not overridden */ | |
407 | if (!nu->ops.recv_buf) | |
408 | nu->ops.recv_buf = nci_uart_default_recv_buf; | |
409 | if (!nu->ops.recv) | |
410 | nu->ops.recv = nci_uart_default_recv; | |
411 | ||
412 | /* Add this driver in the driver list */ | |
fb77ff4f | 413 | if (nci_uart_drivers[nu->driver]) { |
9961127d VC |
414 | pr_err("driver %d is already registered\n", nu->driver); |
415 | return -EBUSY; | |
416 | } | |
417 | nci_uart_drivers[nu->driver] = nu; | |
418 | ||
419 | pr_info("NCI uart driver '%s [%d]' registered\n", nu->name, nu->driver); | |
420 | ||
421 | return 0; | |
422 | } | |
423 | EXPORT_SYMBOL_GPL(nci_uart_register); | |
424 | ||
425 | void nci_uart_unregister(struct nci_uart *nu) | |
426 | { | |
427 | pr_info("NCI uart driver '%s [%d]' unregistered\n", nu->name, | |
428 | nu->driver); | |
429 | ||
430 | /* Remove this driver from the driver list */ | |
431 | nci_uart_drivers[nu->driver] = NULL; | |
432 | } | |
433 | EXPORT_SYMBOL_GPL(nci_uart_unregister); | |
434 | ||
435 | void nci_uart_set_config(struct nci_uart *nu, int baudrate, int flow_ctrl) | |
436 | { | |
437 | struct ktermios new_termios; | |
438 | ||
439 | if (!nu->tty) | |
440 | return; | |
441 | ||
442 | down_read(&nu->tty->termios_rwsem); | |
443 | new_termios = nu->tty->termios; | |
444 | up_read(&nu->tty->termios_rwsem); | |
445 | tty_termios_encode_baud_rate(&new_termios, baudrate, baudrate); | |
446 | ||
447 | if (flow_ctrl) | |
448 | new_termios.c_cflag |= CRTSCTS; | |
449 | else | |
450 | new_termios.c_cflag &= ~CRTSCTS; | |
451 | ||
452 | tty_set_termios(nu->tty, &new_termios); | |
453 | } | |
454 | EXPORT_SYMBOL_GPL(nci_uart_set_config); | |
455 | ||
456 | static struct tty_ldisc_ops nci_uart_ldisc = { | |
457 | .magic = TTY_LDISC_MAGIC, | |
458 | .owner = THIS_MODULE, | |
459 | .name = "n_nci", | |
460 | .open = nci_uart_tty_open, | |
461 | .close = nci_uart_tty_close, | |
462 | .read = nci_uart_tty_read, | |
463 | .write = nci_uart_tty_write, | |
464 | .poll = nci_uart_tty_poll, | |
465 | .receive_buf = nci_uart_tty_receive, | |
466 | .write_wakeup = nci_uart_tty_wakeup, | |
467 | .ioctl = nci_uart_tty_ioctl, | |
468 | }; | |
469 | ||
470 | static int __init nci_uart_init(void) | |
471 | { | |
472 | memset(nci_uart_drivers, 0, sizeof(nci_uart_drivers)); | |
473 | return tty_register_ldisc(N_NCI, &nci_uart_ldisc); | |
474 | } | |
475 | ||
476 | static void __exit nci_uart_exit(void) | |
477 | { | |
478 | tty_unregister_ldisc(N_NCI); | |
479 | } | |
480 | ||
481 | module_init(nci_uart_init); | |
482 | module_exit(nci_uart_exit); | |
483 | ||
484 | MODULE_AUTHOR("Marvell International Ltd."); | |
485 | MODULE_DESCRIPTION("NFC NCI UART driver"); | |
486 | MODULE_LICENSE("GPL"); | |
487 | MODULE_ALIAS_LDISC(N_NCI); |