This source file includes following definitions.
- update_tty_status
- debugfs_init
- debugfs_deinit
- debugfs_rx
- debugfs_tx
- debugfs_init
- debugfs_deinit
- update_tty_status
- debugfs_rx
- debugfs_tx
- ldisc_receive
- handle_tx
- caif_xmit
- ldisc_tx_wakeup
- ser_release
- ldisc_open
- ldisc_close
- register_ldisc
- caifdev_setup
- caif_net_open
- caif_net_close
- caif_ser_init
- caif_ser_exit
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7 #include <linux/hardirq.h>
8 #include <linux/init.h>
9 #include <linux/module.h>
10 #include <linux/device.h>
11 #include <linux/types.h>
12 #include <linux/skbuff.h>
13 #include <linux/netdevice.h>
14 #include <linux/rtnetlink.h>
15 #include <linux/tty.h>
16 #include <linux/file.h>
17 #include <linux/if_arp.h>
18 #include <net/caif/caif_device.h>
19 #include <net/caif/cfcnfg.h>
20 #include <linux/err.h>
21 #include <linux/debugfs.h>
22
23 MODULE_LICENSE("GPL");
24 MODULE_AUTHOR("Sjur Brendeland");
25 MODULE_DESCRIPTION("CAIF serial device TTY line discipline");
26 MODULE_LICENSE("GPL");
27 MODULE_ALIAS_LDISC(N_CAIF);
28
29 #define SEND_QUEUE_LOW 10
30 #define SEND_QUEUE_HIGH 100
31 #define CAIF_SENDING 1
32 #define CAIF_FLOW_OFF_SENT 4
33 #define MAX_WRITE_CHUNK 4096
34 #define ON 1
35 #define OFF 0
36 #define CAIF_MAX_MTU 4096
37
38 static DEFINE_SPINLOCK(ser_lock);
39 static LIST_HEAD(ser_list);
40 static LIST_HEAD(ser_release_list);
41
42 static bool ser_loop;
43 module_param(ser_loop, bool, 0444);
44 MODULE_PARM_DESC(ser_loop, "Run in simulated loopback mode.");
45
46 static bool ser_use_stx = true;
47 module_param(ser_use_stx, bool, 0444);
48 MODULE_PARM_DESC(ser_use_stx, "STX enabled or not.");
49
50 static bool ser_use_fcs = true;
51
52 module_param(ser_use_fcs, bool, 0444);
53 MODULE_PARM_DESC(ser_use_fcs, "FCS enabled or not.");
54
55 static int ser_write_chunk = MAX_WRITE_CHUNK;
56 module_param(ser_write_chunk, int, 0444);
57
58 MODULE_PARM_DESC(ser_write_chunk, "Maximum size of data written to UART.");
59
60 static struct dentry *debugfsdir;
61
62 static int caif_net_open(struct net_device *dev);
63 static int caif_net_close(struct net_device *dev);
64
65 struct ser_device {
66 struct caif_dev_common common;
67 struct list_head node;
68 struct net_device *dev;
69 struct sk_buff_head head;
70 struct tty_struct *tty;
71 bool tx_started;
72 unsigned long state;
73 #ifdef CONFIG_DEBUG_FS
74 struct dentry *debugfs_tty_dir;
75 struct debugfs_blob_wrapper tx_blob;
76 struct debugfs_blob_wrapper rx_blob;
77 u8 rx_data[128];
78 u8 tx_data[128];
79 u8 tty_status;
80
81 #endif
82 };
83
84 static void caifdev_setup(struct net_device *dev);
85 static void ldisc_tx_wakeup(struct tty_struct *tty);
86 #ifdef CONFIG_DEBUG_FS
87 static inline void update_tty_status(struct ser_device *ser)
88 {
89 ser->tty_status =
90 ser->tty->stopped << 5 |
91 ser->tty->flow_stopped << 3 |
92 ser->tty->packet << 2 |
93 ser->tty->port->low_latency << 1;
94 }
95 static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
96 {
97 ser->debugfs_tty_dir = debugfs_create_dir(tty->name, debugfsdir);
98
99 debugfs_create_blob("last_tx_msg", 0400, ser->debugfs_tty_dir,
100 &ser->tx_blob);
101
102 debugfs_create_blob("last_rx_msg", 0400, ser->debugfs_tty_dir,
103 &ser->rx_blob);
104
105 debugfs_create_x32("ser_state", 0400, ser->debugfs_tty_dir,
106 (u32 *)&ser->state);
107
108 debugfs_create_x8("tty_status", 0400, ser->debugfs_tty_dir,
109 &ser->tty_status);
110
111 ser->tx_blob.data = ser->tx_data;
112 ser->tx_blob.size = 0;
113 ser->rx_blob.data = ser->rx_data;
114 ser->rx_blob.size = 0;
115 }
116
117 static inline void debugfs_deinit(struct ser_device *ser)
118 {
119 debugfs_remove_recursive(ser->debugfs_tty_dir);
120 }
121
122 static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
123 {
124 if (size > sizeof(ser->rx_data))
125 size = sizeof(ser->rx_data);
126 memcpy(ser->rx_data, data, size);
127 ser->rx_blob.data = ser->rx_data;
128 ser->rx_blob.size = size;
129 }
130
131 static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
132 {
133 if (size > sizeof(ser->tx_data))
134 size = sizeof(ser->tx_data);
135 memcpy(ser->tx_data, data, size);
136 ser->tx_blob.data = ser->tx_data;
137 ser->tx_blob.size = size;
138 }
139 #else
140 static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
141 {
142 }
143
144 static inline void debugfs_deinit(struct ser_device *ser)
145 {
146 }
147
148 static inline void update_tty_status(struct ser_device *ser)
149 {
150 }
151
152 static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
153 {
154 }
155
156 static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
157 {
158 }
159
160 #endif
161
162 static void ldisc_receive(struct tty_struct *tty, const u8 *data,
163 char *flags, int count)
164 {
165 struct sk_buff *skb = NULL;
166 struct ser_device *ser;
167 int ret;
168
169 ser = tty->disc_data;
170
171
172
173
174
175
176
177
178
179
180
181 if (!ser->common.use_stx && !ser->tx_started) {
182 dev_info(&ser->dev->dev,
183 "Bytes received before initial transmission -"
184 "bytes discarded.\n");
185 return;
186 }
187
188 BUG_ON(ser->dev == NULL);
189
190
191 skb = netdev_alloc_skb(ser->dev, count+1);
192 if (skb == NULL)
193 return;
194 skb_put_data(skb, data, count);
195
196 skb->protocol = htons(ETH_P_CAIF);
197 skb_reset_mac_header(skb);
198 debugfs_rx(ser, data, count);
199
200 ret = netif_rx_ni(skb);
201 if (!ret) {
202 ser->dev->stats.rx_packets++;
203 ser->dev->stats.rx_bytes += count;
204 } else
205 ++ser->dev->stats.rx_dropped;
206 update_tty_status(ser);
207 }
208
209 static int handle_tx(struct ser_device *ser)
210 {
211 struct tty_struct *tty;
212 struct sk_buff *skb;
213 int tty_wr, len, room;
214
215 tty = ser->tty;
216 ser->tx_started = true;
217
218
219 if (test_and_set_bit(CAIF_SENDING, &ser->state))
220 return 0;
221
222
223 while ((skb = skb_peek(&ser->head)) != NULL) {
224
225
226 len = skb->len;
227 room = tty_write_room(tty);
228 if (!room)
229 break;
230 if (room > ser_write_chunk)
231 room = ser_write_chunk;
232 if (len > room)
233 len = room;
234
235
236 if (!ser_loop) {
237 tty_wr = tty->ops->write(tty, skb->data, len);
238 update_tty_status(ser);
239 } else {
240 tty_wr = len;
241 ldisc_receive(tty, skb->data, NULL, len);
242 }
243 ser->dev->stats.tx_packets++;
244 ser->dev->stats.tx_bytes += tty_wr;
245
246
247 if (tty_wr < 0)
248 goto error;
249
250 skb_pull(skb, tty_wr);
251 if (skb->len == 0) {
252 struct sk_buff *tmp = skb_dequeue(&ser->head);
253 WARN_ON(tmp != skb);
254 dev_consume_skb_any(skb);
255 }
256 }
257
258 if (ser->head.qlen <= SEND_QUEUE_LOW &&
259 test_and_clear_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
260 ser->common.flowctrl != NULL)
261 ser->common.flowctrl(ser->dev, ON);
262 clear_bit(CAIF_SENDING, &ser->state);
263 return 0;
264 error:
265 clear_bit(CAIF_SENDING, &ser->state);
266 return tty_wr;
267 }
268
269 static int caif_xmit(struct sk_buff *skb, struct net_device *dev)
270 {
271 struct ser_device *ser;
272
273 BUG_ON(dev == NULL);
274 ser = netdev_priv(dev);
275
276
277 if (ser->head.qlen > SEND_QUEUE_HIGH &&
278 !test_and_set_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
279 ser->common.flowctrl != NULL)
280
281 ser->common.flowctrl(ser->dev, OFF);
282
283 skb_queue_tail(&ser->head, skb);
284 return handle_tx(ser);
285 }
286
287
288 static void ldisc_tx_wakeup(struct tty_struct *tty)
289 {
290 struct ser_device *ser;
291
292 ser = tty->disc_data;
293 BUG_ON(ser == NULL);
294 WARN_ON(ser->tty != tty);
295 handle_tx(ser);
296 }
297
298
299 static void ser_release(struct work_struct *work)
300 {
301 struct list_head list;
302 struct ser_device *ser, *tmp;
303
304 spin_lock(&ser_lock);
305 list_replace_init(&ser_release_list, &list);
306 spin_unlock(&ser_lock);
307
308 if (!list_empty(&list)) {
309 rtnl_lock();
310 list_for_each_entry_safe(ser, tmp, &list, node) {
311 dev_close(ser->dev);
312 unregister_netdevice(ser->dev);
313 debugfs_deinit(ser);
314 }
315 rtnl_unlock();
316 }
317 }
318
319 static DECLARE_WORK(ser_release_work, ser_release);
320
321 static int ldisc_open(struct tty_struct *tty)
322 {
323 struct ser_device *ser;
324 struct net_device *dev;
325 char name[64];
326 int result;
327
328
329 if (tty->ops->write == NULL)
330 return -EOPNOTSUPP;
331 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_TTY_CONFIG))
332 return -EPERM;
333
334
335 ser_release(NULL);
336
337 result = snprintf(name, sizeof(name), "cf%s", tty->name);
338 if (result >= IFNAMSIZ)
339 return -EINVAL;
340 dev = alloc_netdev(sizeof(*ser), name, NET_NAME_UNKNOWN,
341 caifdev_setup);
342 if (!dev)
343 return -ENOMEM;
344
345 ser = netdev_priv(dev);
346 ser->tty = tty_kref_get(tty);
347 ser->dev = dev;
348 debugfs_init(ser, tty);
349 tty->receive_room = N_TTY_BUF_SIZE;
350 tty->disc_data = ser;
351 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
352 rtnl_lock();
353 result = register_netdevice(dev);
354 if (result) {
355 rtnl_unlock();
356 free_netdev(dev);
357 return -ENODEV;
358 }
359
360 spin_lock(&ser_lock);
361 list_add(&ser->node, &ser_list);
362 spin_unlock(&ser_lock);
363 rtnl_unlock();
364 netif_stop_queue(dev);
365 update_tty_status(ser);
366 return 0;
367 }
368
369 static void ldisc_close(struct tty_struct *tty)
370 {
371 struct ser_device *ser = tty->disc_data;
372
373 tty_kref_put(ser->tty);
374
375 spin_lock(&ser_lock);
376 list_move(&ser->node, &ser_release_list);
377 spin_unlock(&ser_lock);
378 schedule_work(&ser_release_work);
379 }
380
381
382 static struct tty_ldisc_ops caif_ldisc = {
383 .owner = THIS_MODULE,
384 .magic = TTY_LDISC_MAGIC,
385 .name = "n_caif",
386 .open = ldisc_open,
387 .close = ldisc_close,
388 .receive_buf = ldisc_receive,
389 .write_wakeup = ldisc_tx_wakeup
390 };
391
392 static int register_ldisc(void)
393 {
394 int result;
395
396 result = tty_register_ldisc(N_CAIF, &caif_ldisc);
397 if (result < 0) {
398 pr_err("cannot register CAIF ldisc=%d err=%d\n", N_CAIF,
399 result);
400 return result;
401 }
402 return result;
403 }
404 static const struct net_device_ops netdev_ops = {
405 .ndo_open = caif_net_open,
406 .ndo_stop = caif_net_close,
407 .ndo_start_xmit = caif_xmit
408 };
409
410 static void caifdev_setup(struct net_device *dev)
411 {
412 struct ser_device *serdev = netdev_priv(dev);
413
414 dev->features = 0;
415 dev->netdev_ops = &netdev_ops;
416 dev->type = ARPHRD_CAIF;
417 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
418 dev->mtu = CAIF_MAX_MTU;
419 dev->priv_flags |= IFF_NO_QUEUE;
420 dev->needs_free_netdev = true;
421 skb_queue_head_init(&serdev->head);
422 serdev->common.link_select = CAIF_LINK_LOW_LATENCY;
423 serdev->common.use_frag = true;
424 serdev->common.use_stx = ser_use_stx;
425 serdev->common.use_fcs = ser_use_fcs;
426 serdev->dev = dev;
427 }
428
429
430 static int caif_net_open(struct net_device *dev)
431 {
432 netif_wake_queue(dev);
433 return 0;
434 }
435
436 static int caif_net_close(struct net_device *dev)
437 {
438 netif_stop_queue(dev);
439 return 0;
440 }
441
442 static int __init caif_ser_init(void)
443 {
444 int ret;
445
446 ret = register_ldisc();
447 debugfsdir = debugfs_create_dir("caif_serial", NULL);
448 return ret;
449 }
450
451 static void __exit caif_ser_exit(void)
452 {
453 spin_lock(&ser_lock);
454 list_splice(&ser_list, &ser_release_list);
455 spin_unlock(&ser_lock);
456 ser_release(NULL);
457 cancel_work_sync(&ser_release_work);
458 tty_unregister_ldisc(N_CAIF);
459 debugfs_remove_recursive(debugfsdir);
460 }
461
462 module_init(caif_ser_init);
463 module_exit(caif_ser_exit);