ARM: 7409/1: Do not call flush_cache_user_range with mmap_sem held
[linux/fpc-iii.git] / drivers / net / caif / caif_serial.c
blob3df0c0f8b8bf93ca98a8829e7c09162a70f384c4
1 /*
2 * Copyright (C) ST-Ericsson AB 2010
3 * Author: Sjur Brendeland / sjur.brandeland@stericsson.com
4 * License terms: GNU General Public License (GPL) version 2
5 */
7 #include <linux/init.h>
8 #include <linux/version.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>
23 MODULE_LICENSE("GPL");
24 MODULE_AUTHOR("Sjur Brendeland<sjur.brandeland@stericsson.com>");
25 MODULE_DESCRIPTION("CAIF serial device TTY line discipline");
26 MODULE_LICENSE("GPL");
27 MODULE_ALIAS_LDISC(N_CAIF);
29 #define SEND_QUEUE_LOW 10
30 #define SEND_QUEUE_HIGH 100
31 #define CAIF_SENDING 1 /* Bit 1 = 0x02*/
32 #define CAIF_FLOW_OFF_SENT 4 /* Bit 4 = 0x10 */
33 #define MAX_WRITE_CHUNK 4096
34 #define ON 1
35 #define OFF 0
36 #define CAIF_MAX_MTU 4096
38 /*This list is protected by the rtnl lock. */
39 static LIST_HEAD(ser_list);
41 static int ser_loop;
42 module_param(ser_loop, bool, S_IRUGO);
43 MODULE_PARM_DESC(ser_loop, "Run in simulated loopback mode.");
45 static int ser_use_stx = 1;
46 module_param(ser_use_stx, bool, S_IRUGO);
47 MODULE_PARM_DESC(ser_use_stx, "STX enabled or not.");
49 static int ser_use_fcs = 1;
51 module_param(ser_use_fcs, bool, S_IRUGO);
52 MODULE_PARM_DESC(ser_use_fcs, "FCS enabled or not.");
54 static int ser_write_chunk = MAX_WRITE_CHUNK;
55 module_param(ser_write_chunk, int, S_IRUGO);
57 MODULE_PARM_DESC(ser_write_chunk, "Maximum size of data written to UART.");
59 static struct dentry *debugfsdir;
61 static int caif_net_open(struct net_device *dev);
62 static int caif_net_close(struct net_device *dev);
64 struct ser_device {
65 struct caif_dev_common common;
66 struct list_head node;
67 struct net_device *dev;
68 struct sk_buff_head head;
69 struct tty_struct *tty;
70 bool tx_started;
71 unsigned long state;
72 char *tty_name;
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;
81 #endif
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)
89 ser->tty_status =
90 ser->tty->stopped << 5 |
91 ser->tty->hw_stopped << 4 |
92 ser->tty->flow_stopped << 3 |
93 ser->tty->packet << 2 |
94 ser->tty->low_latency << 1 |
95 ser->tty->warned;
97 static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
99 ser->debugfs_tty_dir =
100 debugfs_create_dir(tty->name, debugfsdir);
101 if (!IS_ERR(ser->debugfs_tty_dir)) {
102 debugfs_create_blob("last_tx_msg", S_IRUSR,
103 ser->debugfs_tty_dir,
104 &ser->tx_blob);
106 debugfs_create_blob("last_rx_msg", S_IRUSR,
107 ser->debugfs_tty_dir,
108 &ser->rx_blob);
110 debugfs_create_x32("ser_state", S_IRUSR,
111 ser->debugfs_tty_dir,
112 (u32 *)&ser->state);
114 debugfs_create_x8("tty_status", S_IRUSR,
115 ser->debugfs_tty_dir,
116 &ser->tty_status);
119 ser->tx_blob.data = ser->tx_data;
120 ser->tx_blob.size = 0;
121 ser->rx_blob.data = ser->rx_data;
122 ser->rx_blob.size = 0;
125 static inline void debugfs_deinit(struct ser_device *ser)
127 debugfs_remove_recursive(ser->debugfs_tty_dir);
130 static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
132 if (size > sizeof(ser->rx_data))
133 size = sizeof(ser->rx_data);
134 memcpy(ser->rx_data, data, size);
135 ser->rx_blob.data = ser->rx_data;
136 ser->rx_blob.size = size;
139 static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
141 if (size > sizeof(ser->tx_data))
142 size = sizeof(ser->tx_data);
143 memcpy(ser->tx_data, data, size);
144 ser->tx_blob.data = ser->tx_data;
145 ser->tx_blob.size = size;
147 #else
148 static inline void debugfs_init(struct ser_device *ser, struct tty_struct *tty)
152 static inline void debugfs_deinit(struct ser_device *ser)
156 static inline void update_tty_status(struct ser_device *ser)
160 static inline void debugfs_rx(struct ser_device *ser, const u8 *data, int size)
164 static inline void debugfs_tx(struct ser_device *ser, const u8 *data, int size)
168 #endif
170 static void ldisc_receive(struct tty_struct *tty, const u8 *data,
171 char *flags, int count)
173 struct sk_buff *skb = NULL;
174 struct ser_device *ser;
175 int ret;
176 u8 *p;
178 ser = tty->disc_data;
181 * NOTE: flags may contain information about break or overrun.
182 * This is not yet handled.
187 * Workaround for garbage at start of transmission,
188 * only enable if STX handling is not enabled.
190 if (!ser->common.use_stx && !ser->tx_started) {
191 dev_info(&ser->dev->dev,
192 "Bytes received before initial transmission -"
193 "bytes discarded.\n");
194 return;
197 BUG_ON(ser->dev == NULL);
199 /* Get a suitable caif packet and copy in data. */
200 skb = netdev_alloc_skb(ser->dev, count+1);
201 if (skb == NULL)
202 return;
203 p = skb_put(skb, count);
204 memcpy(p, data, count);
206 skb->protocol = htons(ETH_P_CAIF);
207 skb_reset_mac_header(skb);
208 skb->dev = ser->dev;
209 debugfs_rx(ser, data, count);
210 /* Push received packet up the stack. */
211 ret = netif_rx_ni(skb);
212 if (!ret) {
213 ser->dev->stats.rx_packets++;
214 ser->dev->stats.rx_bytes += count;
215 } else
216 ++ser->dev->stats.rx_dropped;
217 update_tty_status(ser);
220 static int handle_tx(struct ser_device *ser)
222 struct tty_struct *tty;
223 struct sk_buff *skb;
224 int tty_wr, len, room;
226 tty = ser->tty;
227 ser->tx_started = true;
229 /* Enter critical section */
230 if (test_and_set_bit(CAIF_SENDING, &ser->state))
231 return 0;
233 /* skb_peek is safe because handle_tx is called after skb_queue_tail */
234 while ((skb = skb_peek(&ser->head)) != NULL) {
236 /* Make sure you don't write too much */
237 len = skb->len;
238 room = tty_write_room(tty);
239 if (!room)
240 break;
241 if (room > ser_write_chunk)
242 room = ser_write_chunk;
243 if (len > room)
244 len = room;
246 /* Write to tty or loopback */
247 if (!ser_loop) {
248 tty_wr = tty->ops->write(tty, skb->data, len);
249 update_tty_status(ser);
250 } else {
251 tty_wr = len;
252 ldisc_receive(tty, skb->data, NULL, len);
254 ser->dev->stats.tx_packets++;
255 ser->dev->stats.tx_bytes += tty_wr;
257 /* Error on TTY ?! */
258 if (tty_wr < 0)
259 goto error;
260 /* Reduce buffer written, and discard if empty */
261 skb_pull(skb, tty_wr);
262 if (skb->len == 0) {
263 struct sk_buff *tmp = skb_dequeue(&ser->head);
264 BUG_ON(tmp != skb);
265 if (in_interrupt())
266 dev_kfree_skb_irq(skb);
267 else
268 kfree_skb(skb);
271 /* Send flow off if queue is empty */
272 if (ser->head.qlen <= SEND_QUEUE_LOW &&
273 test_and_clear_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
274 ser->common.flowctrl != NULL)
275 ser->common.flowctrl(ser->dev, ON);
276 clear_bit(CAIF_SENDING, &ser->state);
277 return 0;
278 error:
279 clear_bit(CAIF_SENDING, &ser->state);
280 return tty_wr;
283 static int caif_xmit(struct sk_buff *skb, struct net_device *dev)
285 struct ser_device *ser;
287 BUG_ON(dev == NULL);
288 ser = netdev_priv(dev);
290 /* Send flow off once, on high water mark */
291 if (ser->head.qlen > SEND_QUEUE_HIGH &&
292 !test_and_set_bit(CAIF_FLOW_OFF_SENT, &ser->state) &&
293 ser->common.flowctrl != NULL)
295 ser->common.flowctrl(ser->dev, OFF);
297 skb_queue_tail(&ser->head, skb);
298 return handle_tx(ser);
302 static void ldisc_tx_wakeup(struct tty_struct *tty)
304 struct ser_device *ser;
306 ser = tty->disc_data;
307 BUG_ON(ser == NULL);
308 BUG_ON(ser->tty != tty);
309 handle_tx(ser);
313 static int ldisc_open(struct tty_struct *tty)
315 struct ser_device *ser;
316 struct net_device *dev;
317 char name[64];
318 int result;
320 /* No write no play */
321 if (tty->ops->write == NULL)
322 return -EOPNOTSUPP;
323 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_TTY_CONFIG))
324 return -EPERM;
326 sprintf(name, "cf%s", tty->name);
327 dev = alloc_netdev(sizeof(*ser), name, caifdev_setup);
328 ser = netdev_priv(dev);
329 ser->tty = tty_kref_get(tty);
330 ser->dev = dev;
331 debugfs_init(ser, tty);
332 tty->receive_room = N_TTY_BUF_SIZE;
333 tty->disc_data = ser;
334 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
335 rtnl_lock();
336 result = register_netdevice(dev);
337 if (result) {
338 rtnl_unlock();
339 free_netdev(dev);
340 return -ENODEV;
343 list_add(&ser->node, &ser_list);
344 rtnl_unlock();
345 netif_stop_queue(dev);
346 update_tty_status(ser);
347 return 0;
350 static void ldisc_close(struct tty_struct *tty)
352 struct ser_device *ser = tty->disc_data;
353 /* Remove may be called inside or outside of rtnl_lock */
354 int islocked = rtnl_is_locked();
356 if (!islocked)
357 rtnl_lock();
358 /* device is freed automagically by net-sysfs */
359 dev_close(ser->dev);
360 unregister_netdevice(ser->dev);
361 list_del(&ser->node);
362 debugfs_deinit(ser);
363 tty_kref_put(ser->tty);
364 if (!islocked)
365 rtnl_unlock();
368 /* The line discipline structure. */
369 static struct tty_ldisc_ops caif_ldisc = {
370 .owner = THIS_MODULE,
371 .magic = TTY_LDISC_MAGIC,
372 .name = "n_caif",
373 .open = ldisc_open,
374 .close = ldisc_close,
375 .receive_buf = ldisc_receive,
376 .write_wakeup = ldisc_tx_wakeup
379 static int register_ldisc(void)
381 int result;
383 result = tty_register_ldisc(N_CAIF, &caif_ldisc);
384 if (result < 0) {
385 pr_err("cannot register CAIF ldisc=%d err=%d\n", N_CAIF,
386 result);
387 return result;
389 return result;
391 static const struct net_device_ops netdev_ops = {
392 .ndo_open = caif_net_open,
393 .ndo_stop = caif_net_close,
394 .ndo_start_xmit = caif_xmit
397 static void caifdev_setup(struct net_device *dev)
399 struct ser_device *serdev = netdev_priv(dev);
401 dev->features = 0;
402 dev->netdev_ops = &netdev_ops;
403 dev->type = ARPHRD_CAIF;
404 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
405 dev->mtu = CAIF_MAX_MTU;
406 dev->tx_queue_len = 0;
407 dev->destructor = free_netdev;
408 skb_queue_head_init(&serdev->head);
409 serdev->common.link_select = CAIF_LINK_LOW_LATENCY;
410 serdev->common.use_frag = true;
411 serdev->common.use_stx = ser_use_stx;
412 serdev->common.use_fcs = ser_use_fcs;
413 serdev->dev = dev;
417 static int caif_net_open(struct net_device *dev)
419 netif_wake_queue(dev);
420 return 0;
423 static int caif_net_close(struct net_device *dev)
425 netif_stop_queue(dev);
426 return 0;
429 static int __init caif_ser_init(void)
431 int ret;
433 ret = register_ldisc();
434 debugfsdir = debugfs_create_dir("caif_serial", NULL);
435 return ret;
438 static void __exit caif_ser_exit(void)
440 struct ser_device *ser = NULL;
441 struct list_head *node;
442 struct list_head *_tmp;
444 list_for_each_safe(node, _tmp, &ser_list) {
445 ser = list_entry(node, struct ser_device, node);
446 dev_close(ser->dev);
447 unregister_netdevice(ser->dev);
448 list_del(node);
450 tty_unregister_ldisc(N_CAIF);
451 debugfs_remove_recursive(debugfsdir);
454 module_init(caif_ser_init);
455 module_exit(caif_ser_exit);