Commit | Line | Data |
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7dec65c8 JH |
1 | /* |
2 | * | |
3 | * Bluetooth HCI Three-wire UART driver | |
4 | * | |
5 | * Copyright (C) 2012 Intel Corporation | |
6 | * | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
21 | * | |
22 | */ | |
23 | ||
24 | #include <linux/kernel.h> | |
25 | #include <linux/errno.h> | |
26 | #include <linux/skbuff.h> | |
27 | ||
28 | #include <net/bluetooth/bluetooth.h> | |
29 | #include <net/bluetooth/hci_core.h> | |
30 | ||
31 | #include "hci_uart.h" | |
32 | ||
3f27e95b JH |
33 | #define H5_TXWINSIZE 4 |
34 | ||
35 | #define H5_ACK_TIMEOUT msecs_to_jiffies(250) | |
36 | ||
bc1f35b9 JH |
37 | /* |
38 | * Maximum Three-wire packet: | |
39 | * 4 byte header + max value for 12-bit length + 2 bytes for CRC | |
40 | */ | |
41 | #define H5_MAX_LEN (4 + 0xfff + 2) | |
42 | ||
43 | #define SLIP_DELIMITER 0xc0 | |
44 | #define SLIP_ESC 0xdb | |
45 | #define SLIP_ESC_DELIM 0xdc | |
46 | #define SLIP_ESC_ESC 0xdd | |
47 | ||
7d664fba | 48 | struct h5 { |
bc1f35b9 JH |
49 | struct sk_buff_head unack; /* Unack'ed packets queue */ |
50 | struct sk_buff_head rel; /* Reliable packets queue */ | |
51 | struct sk_buff_head unrel; /* Unreliable packets queue */ | |
52 | ||
53 | struct sk_buff *rx_skb; /* Receive buffer */ | |
54 | size_t rx_pending; /* Expecting more bytes */ | |
55 | bool rx_esc; /* SLIP escape mode */ | |
7d664fba | 56 | |
bc1f35b9 | 57 | int (*rx_func) (struct hci_uart *hu, u8 c); |
7d664fba | 58 | |
bc1f35b9 | 59 | struct timer_list timer; /* Retransmission timer */ |
3f27e95b | 60 | |
bc1f35b9 | 61 | bool txack_req; |
7d664fba | 62 | |
bc1f35b9 | 63 | u8 msgq_txseq; |
7d664fba JH |
64 | }; |
65 | ||
bc1f35b9 JH |
66 | static void h5_reset_rx(struct h5 *h5); |
67 | ||
3f27e95b JH |
68 | static void h5_timed_event(unsigned long arg) |
69 | { | |
70 | struct hci_uart *hu = (struct hci_uart *) arg; | |
71 | struct h5 *h5 = hu->priv; | |
72 | struct sk_buff *skb; | |
73 | unsigned long flags; | |
74 | ||
75 | BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen); | |
76 | ||
77 | spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING); | |
78 | ||
79 | while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) { | |
80 | h5->msgq_txseq = (h5->msgq_txseq - 1) & 0x07; | |
81 | skb_queue_head(&h5->rel, skb); | |
82 | } | |
83 | ||
84 | spin_unlock_irqrestore(&h5->unack.lock, flags); | |
85 | ||
86 | hci_uart_tx_wakeup(hu); | |
87 | } | |
88 | ||
7dec65c8 JH |
89 | static int h5_open(struct hci_uart *hu) |
90 | { | |
7d664fba JH |
91 | struct h5 *h5; |
92 | ||
93 | BT_DBG("hu %p", hu); | |
94 | ||
95 | h5 = kzalloc(sizeof(*h5), GFP_KERNEL); | |
96 | if (!h5) | |
97 | return -ENOMEM; | |
98 | ||
99 | hu->priv = h5; | |
100 | ||
101 | skb_queue_head_init(&h5->unack); | |
102 | skb_queue_head_init(&h5->rel); | |
103 | skb_queue_head_init(&h5->unrel); | |
104 | ||
bc1f35b9 JH |
105 | h5_reset_rx(h5); |
106 | ||
3f27e95b JH |
107 | init_timer(&h5->timer); |
108 | h5->timer.function = h5_timed_event; | |
109 | h5->timer.data = (unsigned long) hu; | |
110 | ||
7d664fba | 111 | return 0; |
7dec65c8 JH |
112 | } |
113 | ||
114 | static int h5_close(struct hci_uart *hu) | |
115 | { | |
7d664fba JH |
116 | struct h5 *h5 = hu->priv; |
117 | ||
118 | skb_queue_purge(&h5->unack); | |
119 | skb_queue_purge(&h5->rel); | |
120 | skb_queue_purge(&h5->unrel); | |
121 | ||
3f27e95b JH |
122 | del_timer(&h5->timer); |
123 | ||
7d664fba JH |
124 | kfree(h5); |
125 | ||
126 | return 0; | |
7dec65c8 JH |
127 | } |
128 | ||
bc1f35b9 JH |
129 | static void h5_handle_internal_rx(struct hci_uart *hu) |
130 | { | |
131 | BT_DBG("%s", hu->hdev->name); | |
132 | } | |
133 | ||
134 | static void h5_complete_rx_pkt(struct hci_uart *hu) | |
135 | { | |
136 | struct h5 *h5 = hu->priv; | |
137 | u8 pkt_type; | |
138 | ||
139 | BT_DBG("%s", hu->hdev->name); | |
140 | ||
141 | pkt_type = h5->rx_skb->data[1] & 0x0f; | |
142 | ||
143 | switch (pkt_type) { | |
144 | case HCI_EVENT_PKT: | |
145 | case HCI_ACLDATA_PKT: | |
146 | case HCI_SCODATA_PKT: | |
147 | bt_cb(h5->rx_skb)->pkt_type = pkt_type; | |
148 | ||
149 | /* Remove Three-wire header */ | |
150 | skb_pull(h5->rx_skb, 4); | |
151 | ||
152 | hci_recv_frame(h5->rx_skb); | |
153 | h5->rx_skb = NULL; | |
154 | ||
155 | break; | |
156 | ||
157 | default: | |
158 | h5_handle_internal_rx(hu); | |
159 | break; | |
160 | } | |
161 | ||
162 | h5_reset_rx(h5); | |
163 | } | |
164 | ||
165 | static int h5_rx_crc(struct hci_uart *hu, unsigned char c) | |
166 | { | |
167 | struct h5 *h5 = hu->priv; | |
168 | ||
169 | BT_DBG("%s 0x%02hhx", hu->hdev->name, c); | |
170 | ||
171 | h5_complete_rx_pkt(hu); | |
172 | h5_reset_rx(h5); | |
173 | ||
174 | return 0; | |
175 | } | |
176 | ||
177 | static int h5_rx_payload(struct hci_uart *hu, unsigned char c) | |
178 | { | |
179 | struct h5 *h5 = hu->priv; | |
180 | const unsigned char *hdr = h5->rx_skb->data; | |
181 | ||
182 | BT_DBG("%s 0x%02hhx", hu->hdev->name, c); | |
183 | ||
184 | if ((hdr[0] >> 4) & 0x01) { | |
185 | h5->rx_func = h5_rx_crc; | |
186 | h5->rx_pending = 2; | |
187 | } else { | |
188 | h5_complete_rx_pkt(hu); | |
189 | h5_reset_rx(h5); | |
190 | } | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
195 | static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c) | |
196 | { | |
197 | struct h5 *h5 = hu->priv; | |
198 | const unsigned char *hdr = h5->rx_skb->data; | |
199 | ||
200 | BT_DBG("%s 0x%02hhx", hu->hdev->name, c); | |
201 | ||
202 | if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) { | |
203 | BT_ERR("Invalid header checksum"); | |
204 | h5_reset_rx(h5); | |
205 | return 0; | |
206 | } | |
207 | ||
208 | h5->rx_func = h5_rx_payload; | |
209 | h5->rx_pending = ((hdr[1] >> 4) & 0xff) + (hdr[2] << 4); | |
210 | ||
211 | return 0; | |
212 | } | |
213 | ||
214 | static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c) | |
215 | { | |
216 | struct h5 *h5 = hu->priv; | |
217 | ||
218 | BT_DBG("%s 0x%02hhx", hu->hdev->name, c); | |
219 | ||
220 | if (c == SLIP_DELIMITER) | |
221 | return 1; | |
222 | ||
223 | h5->rx_func = h5_rx_3wire_hdr; | |
224 | h5->rx_pending = 4; | |
225 | ||
226 | h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC); | |
227 | if (!h5->rx_skb) { | |
228 | BT_ERR("Can't allocate mem for new packet"); | |
229 | h5_reset_rx(h5); | |
230 | return -ENOMEM; | |
231 | } | |
232 | ||
233 | h5->rx_skb->dev = (void *) hu->hdev; | |
234 | ||
235 | return 0; | |
236 | } | |
237 | ||
238 | static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c) | |
239 | { | |
240 | struct h5 *h5 = hu->priv; | |
241 | ||
242 | BT_DBG("%s 0x%02hhx", hu->hdev->name, c); | |
243 | ||
244 | if (c == SLIP_DELIMITER) | |
245 | h5->rx_func = h5_rx_pkt_start; | |
246 | ||
247 | return 1; | |
248 | } | |
249 | ||
250 | static void h5_unslip_one_byte(struct h5 *h5, unsigned char c) | |
251 | { | |
252 | const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC; | |
253 | const u8 *byte = &c; | |
254 | ||
255 | if (!h5->rx_esc && c == SLIP_ESC) { | |
256 | h5->rx_esc = true; | |
257 | return; | |
258 | } | |
259 | ||
260 | if (h5->rx_esc) { | |
261 | switch (c) { | |
262 | case SLIP_ESC_DELIM: | |
263 | byte = &delim; | |
264 | break; | |
265 | case SLIP_ESC_ESC: | |
266 | byte = &esc; | |
267 | break; | |
268 | default: | |
269 | BT_ERR("Invalid esc byte 0x%02hhx", c); | |
270 | h5_reset_rx(h5); | |
271 | return; | |
272 | } | |
273 | ||
274 | h5->rx_esc = false; | |
275 | } | |
276 | ||
277 | memcpy(skb_put(h5->rx_skb, 1), byte, 1); | |
278 | h5->rx_pending--; | |
279 | ||
280 | BT_DBG("unsliped 0x%02hhx", *byte); | |
281 | } | |
282 | ||
283 | static void h5_reset_rx(struct h5 *h5) | |
284 | { | |
285 | if (h5->rx_skb) { | |
286 | kfree_skb(h5->rx_skb); | |
287 | h5->rx_skb = NULL; | |
288 | } | |
289 | ||
290 | h5->rx_func = h5_rx_delimiter; | |
291 | h5->rx_pending = 0; | |
292 | h5->rx_esc = false; | |
293 | } | |
294 | ||
7dec65c8 JH |
295 | static int h5_recv(struct hci_uart *hu, void *data, int count) |
296 | { | |
bc1f35b9 JH |
297 | struct h5 *h5 = hu->priv; |
298 | unsigned char *ptr = data; | |
299 | ||
300 | BT_DBG("%s count %d", hu->hdev->name, count); | |
301 | ||
302 | while (count > 0) { | |
303 | int processed; | |
304 | ||
305 | if (h5->rx_pending > 0) { | |
306 | if (*ptr == SLIP_DELIMITER) { | |
307 | BT_ERR("Too short H5 packet"); | |
308 | h5_reset_rx(h5); | |
309 | continue; | |
310 | } | |
311 | ||
312 | h5_unslip_one_byte(h5, *ptr); | |
313 | ||
314 | ptr++; count--; | |
315 | continue; | |
316 | } | |
317 | ||
318 | processed = h5->rx_func(hu, *ptr); | |
319 | if (processed < 0) | |
320 | return processed; | |
321 | ||
322 | ptr += processed; | |
323 | count -= processed; | |
324 | } | |
325 | ||
326 | return 0; | |
7dec65c8 JH |
327 | } |
328 | ||
329 | static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb) | |
330 | { | |
7d664fba JH |
331 | struct h5 *h5 = hu->priv; |
332 | ||
333 | if (skb->len > 0xfff) { | |
334 | BT_ERR("Packet too long (%u bytes)", skb->len); | |
335 | kfree_skb(skb); | |
336 | return 0; | |
337 | } | |
338 | ||
339 | switch (bt_cb(skb)->pkt_type) { | |
340 | case HCI_ACLDATA_PKT: | |
341 | case HCI_COMMAND_PKT: | |
342 | skb_queue_tail(&h5->rel, skb); | |
343 | break; | |
344 | ||
345 | case HCI_SCODATA_PKT: | |
346 | skb_queue_tail(&h5->unrel, skb); | |
347 | break; | |
348 | ||
349 | default: | |
350 | BT_ERR("Unknown packet type %u", bt_cb(skb)->pkt_type); | |
351 | kfree_skb(skb); | |
352 | break; | |
353 | } | |
354 | ||
355 | return 0; | |
356 | } | |
357 | ||
358 | static struct sk_buff *h5_prepare_pkt(struct h5 *h5, struct sk_buff *skb) | |
359 | { | |
360 | h5->txack_req = false; | |
361 | return NULL; | |
362 | } | |
363 | ||
364 | static struct sk_buff *h5_prepare_ack(struct h5 *h5) | |
365 | { | |
366 | h5->txack_req = false; | |
367 | return NULL; | |
7dec65c8 JH |
368 | } |
369 | ||
370 | static struct sk_buff *h5_dequeue(struct hci_uart *hu) | |
371 | { | |
7d664fba | 372 | struct h5 *h5 = hu->priv; |
3f27e95b | 373 | unsigned long flags; |
7d664fba JH |
374 | struct sk_buff *skb, *nskb; |
375 | ||
376 | if ((skb = skb_dequeue(&h5->unrel)) != NULL) { | |
377 | nskb = h5_prepare_pkt(h5, skb); | |
378 | if (nskb) { | |
379 | kfree_skb(skb); | |
380 | return nskb; | |
381 | } | |
382 | ||
383 | skb_queue_head(&h5->unrel, skb); | |
384 | BT_ERR("Could not dequeue pkt because alloc_skb failed"); | |
385 | } | |
386 | ||
3f27e95b JH |
387 | spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING); |
388 | ||
389 | if (h5->unack.qlen >= H5_TXWINSIZE) | |
390 | goto unlock; | |
391 | ||
392 | if ((skb = skb_dequeue(&h5->rel)) != NULL) { | |
393 | nskb = h5_prepare_pkt(h5, skb); | |
394 | ||
395 | if (nskb) { | |
396 | __skb_queue_tail(&h5->unack, skb); | |
397 | mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT); | |
398 | spin_unlock_irqrestore(&h5->unack.lock, flags); | |
399 | return nskb; | |
400 | } | |
401 | ||
402 | skb_queue_head(&h5->rel, skb); | |
403 | BT_ERR("Could not dequeue pkt because alloc_skb failed"); | |
404 | } | |
405 | ||
406 | unlock: | |
407 | spin_unlock_irqrestore(&h5->unack.lock, flags); | |
408 | ||
7d664fba JH |
409 | if (h5->txack_req) |
410 | return h5_prepare_ack(h5); | |
411 | ||
7dec65c8 JH |
412 | return NULL; |
413 | } | |
414 | ||
415 | static int h5_flush(struct hci_uart *hu) | |
416 | { | |
7d664fba JH |
417 | BT_DBG("hu %p", hu); |
418 | return 0; | |
7dec65c8 JH |
419 | } |
420 | ||
421 | static struct hci_uart_proto h5p = { | |
422 | .id = HCI_UART_3WIRE, | |
423 | .open = h5_open, | |
424 | .close = h5_close, | |
425 | .recv = h5_recv, | |
426 | .enqueue = h5_enqueue, | |
427 | .dequeue = h5_dequeue, | |
428 | .flush = h5_flush, | |
429 | }; | |
430 | ||
431 | int __init h5_init(void) | |
432 | { | |
433 | int err = hci_uart_register_proto(&h5p); | |
434 | ||
435 | if (!err) | |
436 | BT_INFO("HCI Three-wire UART (H5) protocol initialized"); | |
437 | else | |
438 | BT_ERR("HCI Three-wire UART (H5) protocol init failed"); | |
439 | ||
440 | return err; | |
441 | } | |
442 | ||
443 | int __exit h5_deinit(void) | |
444 | { | |
445 | return hci_uart_unregister_proto(&h5p); | |
446 | } |