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c1dca562 DB |
1 | /* |
2 | * u_serial.c - utilities for USB gadget "serial port"/TTY support | |
3 | * | |
4 | * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com) | |
5 | * Copyright (C) 2008 David Brownell | |
6 | * Copyright (C) 2008 by Nokia Corporation | |
7 | * | |
8 | * This code also borrows from usbserial.c, which is | |
9 | * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com) | |
10 | * Copyright (C) 2000 Peter Berger (pberger@brimson.com) | |
11 | * Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com) | |
12 | * | |
13 | * This software is distributed under the terms of the GNU General | |
14 | * Public License ("GPL") as published by the Free Software Foundation, | |
15 | * either version 2 of that License or (at your option) any later version. | |
16 | */ | |
17 | ||
18 | /* #define VERBOSE_DEBUG */ | |
19 | ||
20 | #include <linux/kernel.h> | |
21 | #include <linux/interrupt.h> | |
22 | #include <linux/device.h> | |
23 | #include <linux/delay.h> | |
24 | #include <linux/tty.h> | |
25 | #include <linux/tty_flip.h> | |
5a0e3ad6 | 26 | #include <linux/slab.h> |
c1dca562 DB |
27 | |
28 | #include "u_serial.h" | |
29 | ||
30 | ||
31 | /* | |
32 | * This component encapsulates the TTY layer glue needed to provide basic | |
33 | * "serial port" functionality through the USB gadget stack. Each such | |
34 | * port is exposed through a /dev/ttyGS* node. | |
35 | * | |
36 | * After initialization (gserial_setup), these TTY port devices stay | |
37 | * available until they are removed (gserial_cleanup). Each one may be | |
38 | * connected to a USB function (gserial_connect), or disconnected (with | |
39 | * gserial_disconnect) when the USB host issues a config change event. | |
40 | * Data can only flow when the port is connected to the host. | |
41 | * | |
42 | * A given TTY port can be made available in multiple configurations. | |
43 | * For example, each one might expose a ttyGS0 node which provides a | |
44 | * login application. In one case that might use CDC ACM interface 0, | |
45 | * while another configuration might use interface 3 for that. The | |
46 | * work to handle that (including descriptor management) is not part | |
47 | * of this component. | |
48 | * | |
49 | * Configurations may expose more than one TTY port. For example, if | |
50 | * ttyGS0 provides login service, then ttyGS1 might provide dialer access | |
51 | * for a telephone or fax link. And ttyGS2 might be something that just | |
52 | * needs a simple byte stream interface for some messaging protocol that | |
53 | * is managed in userspace ... OBEX, PTP, and MTP have been mentioned. | |
54 | */ | |
55 | ||
937ef73d DB |
56 | #define PREFIX "ttyGS" |
57 | ||
c1dca562 DB |
58 | /* |
59 | * gserial is the lifecycle interface, used by USB functions | |
60 | * gs_port is the I/O nexus, used by the tty driver | |
61 | * tty_struct links to the tty/filesystem framework | |
62 | * | |
63 | * gserial <---> gs_port ... links will be null when the USB link is | |
1f1ba11b DB |
64 | * inactive; managed by gserial_{connect,disconnect}(). each gserial |
65 | * instance can wrap its own USB control protocol. | |
c1dca562 DB |
66 | * gserial->ioport == usb_ep->driver_data ... gs_port |
67 | * gs_port->port_usb ... gserial | |
68 | * | |
69 | * gs_port <---> tty_struct ... links will be null when the TTY file | |
70 | * isn't opened; managed by gs_open()/gs_close() | |
71 | * gserial->port_tty ... tty_struct | |
72 | * tty_struct->driver_data ... gserial | |
73 | */ | |
74 | ||
75 | /* RX and TX queues can buffer QUEUE_SIZE packets before they hit the | |
76 | * next layer of buffering. For TX that's a circular buffer; for RX | |
77 | * consider it a NOP. A third layer is provided by the TTY code. | |
78 | */ | |
79 | #define QUEUE_SIZE 16 | |
80 | #define WRITE_BUF_SIZE 8192 /* TX only */ | |
81 | ||
82 | /* circular buffer */ | |
83 | struct gs_buf { | |
84 | unsigned buf_size; | |
85 | char *buf_buf; | |
86 | char *buf_get; | |
87 | char *buf_put; | |
88 | }; | |
89 | ||
90 | /* | |
91 | * The port structure holds info for each port, one for each minor number | |
92 | * (and thus for each /dev/ node). | |
93 | */ | |
94 | struct gs_port { | |
95 | spinlock_t port_lock; /* guard port_* access */ | |
96 | ||
97 | struct gserial *port_usb; | |
98 | struct tty_struct *port_tty; | |
99 | ||
100 | unsigned open_count; | |
101 | bool openclose; /* open/close in progress */ | |
102 | u8 port_num; | |
103 | ||
104 | wait_queue_head_t close_wait; /* wait for last close */ | |
105 | ||
106 | struct list_head read_pool; | |
937ef73d DB |
107 | struct list_head read_queue; |
108 | unsigned n_read; | |
c1dca562 DB |
109 | struct tasklet_struct push; |
110 | ||
111 | struct list_head write_pool; | |
112 | struct gs_buf port_write_buf; | |
113 | wait_queue_head_t drain_wait; /* wait while writes drain */ | |
114 | ||
115 | /* REVISIT this state ... */ | |
116 | struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */ | |
117 | }; | |
118 | ||
119 | /* increase N_PORTS if you need more */ | |
120 | #define N_PORTS 4 | |
121 | static struct portmaster { | |
122 | struct mutex lock; /* protect open/close */ | |
123 | struct gs_port *port; | |
124 | } ports[N_PORTS]; | |
125 | static unsigned n_ports; | |
126 | ||
127 | #define GS_CLOSE_TIMEOUT 15 /* seconds */ | |
128 | ||
129 | ||
130 | ||
131 | #ifdef VERBOSE_DEBUG | |
132 | #define pr_vdebug(fmt, arg...) \ | |
133 | pr_debug(fmt, ##arg) | |
134 | #else | |
135 | #define pr_vdebug(fmt, arg...) \ | |
136 | ({ if (0) pr_debug(fmt, ##arg); }) | |
137 | #endif | |
138 | ||
139 | /*-------------------------------------------------------------------------*/ | |
140 | ||
141 | /* Circular Buffer */ | |
142 | ||
143 | /* | |
144 | * gs_buf_alloc | |
145 | * | |
146 | * Allocate a circular buffer and all associated memory. | |
147 | */ | |
148 | static int gs_buf_alloc(struct gs_buf *gb, unsigned size) | |
149 | { | |
150 | gb->buf_buf = kmalloc(size, GFP_KERNEL); | |
151 | if (gb->buf_buf == NULL) | |
152 | return -ENOMEM; | |
153 | ||
154 | gb->buf_size = size; | |
155 | gb->buf_put = gb->buf_buf; | |
156 | gb->buf_get = gb->buf_buf; | |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | /* | |
162 | * gs_buf_free | |
163 | * | |
164 | * Free the buffer and all associated memory. | |
165 | */ | |
166 | static void gs_buf_free(struct gs_buf *gb) | |
167 | { | |
168 | kfree(gb->buf_buf); | |
169 | gb->buf_buf = NULL; | |
170 | } | |
171 | ||
172 | /* | |
173 | * gs_buf_clear | |
174 | * | |
175 | * Clear out all data in the circular buffer. | |
176 | */ | |
177 | static void gs_buf_clear(struct gs_buf *gb) | |
178 | { | |
179 | gb->buf_get = gb->buf_put; | |
180 | /* equivalent to a get of all data available */ | |
181 | } | |
182 | ||
183 | /* | |
184 | * gs_buf_data_avail | |
185 | * | |
1f1ba11b | 186 | * Return the number of bytes of data written into the circular |
c1dca562 DB |
187 | * buffer. |
188 | */ | |
189 | static unsigned gs_buf_data_avail(struct gs_buf *gb) | |
190 | { | |
191 | return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size; | |
192 | } | |
193 | ||
194 | /* | |
195 | * gs_buf_space_avail | |
196 | * | |
197 | * Return the number of bytes of space available in the circular | |
198 | * buffer. | |
199 | */ | |
200 | static unsigned gs_buf_space_avail(struct gs_buf *gb) | |
201 | { | |
202 | return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size; | |
203 | } | |
204 | ||
205 | /* | |
206 | * gs_buf_put | |
207 | * | |
208 | * Copy data data from a user buffer and put it into the circular buffer. | |
209 | * Restrict to the amount of space available. | |
210 | * | |
211 | * Return the number of bytes copied. | |
212 | */ | |
213 | static unsigned | |
214 | gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count) | |
215 | { | |
216 | unsigned len; | |
217 | ||
218 | len = gs_buf_space_avail(gb); | |
219 | if (count > len) | |
220 | count = len; | |
221 | ||
222 | if (count == 0) | |
223 | return 0; | |
224 | ||
225 | len = gb->buf_buf + gb->buf_size - gb->buf_put; | |
226 | if (count > len) { | |
227 | memcpy(gb->buf_put, buf, len); | |
228 | memcpy(gb->buf_buf, buf+len, count - len); | |
229 | gb->buf_put = gb->buf_buf + count - len; | |
230 | } else { | |
231 | memcpy(gb->buf_put, buf, count); | |
232 | if (count < len) | |
233 | gb->buf_put += count; | |
234 | else /* count == len */ | |
235 | gb->buf_put = gb->buf_buf; | |
236 | } | |
237 | ||
238 | return count; | |
239 | } | |
240 | ||
241 | /* | |
242 | * gs_buf_get | |
243 | * | |
244 | * Get data from the circular buffer and copy to the given buffer. | |
245 | * Restrict to the amount of data available. | |
246 | * | |
247 | * Return the number of bytes copied. | |
248 | */ | |
249 | static unsigned | |
250 | gs_buf_get(struct gs_buf *gb, char *buf, unsigned count) | |
251 | { | |
252 | unsigned len; | |
253 | ||
254 | len = gs_buf_data_avail(gb); | |
255 | if (count > len) | |
256 | count = len; | |
257 | ||
258 | if (count == 0) | |
259 | return 0; | |
260 | ||
261 | len = gb->buf_buf + gb->buf_size - gb->buf_get; | |
262 | if (count > len) { | |
263 | memcpy(buf, gb->buf_get, len); | |
264 | memcpy(buf+len, gb->buf_buf, count - len); | |
265 | gb->buf_get = gb->buf_buf + count - len; | |
266 | } else { | |
267 | memcpy(buf, gb->buf_get, count); | |
268 | if (count < len) | |
269 | gb->buf_get += count; | |
270 | else /* count == len */ | |
271 | gb->buf_get = gb->buf_buf; | |
272 | } | |
273 | ||
274 | return count; | |
275 | } | |
276 | ||
277 | /*-------------------------------------------------------------------------*/ | |
278 | ||
279 | /* I/O glue between TTY (upper) and USB function (lower) driver layers */ | |
280 | ||
281 | /* | |
282 | * gs_alloc_req | |
283 | * | |
284 | * Allocate a usb_request and its buffer. Returns a pointer to the | |
285 | * usb_request or NULL if there is an error. | |
286 | */ | |
1f1ba11b | 287 | struct usb_request * |
c1dca562 DB |
288 | gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) |
289 | { | |
290 | struct usb_request *req; | |
291 | ||
292 | req = usb_ep_alloc_request(ep, kmalloc_flags); | |
293 | ||
294 | if (req != NULL) { | |
295 | req->length = len; | |
296 | req->buf = kmalloc(len, kmalloc_flags); | |
297 | if (req->buf == NULL) { | |
298 | usb_ep_free_request(ep, req); | |
299 | return NULL; | |
300 | } | |
301 | } | |
302 | ||
303 | return req; | |
304 | } | |
305 | ||
306 | /* | |
307 | * gs_free_req | |
308 | * | |
309 | * Free a usb_request and its buffer. | |
310 | */ | |
1f1ba11b | 311 | void gs_free_req(struct usb_ep *ep, struct usb_request *req) |
c1dca562 DB |
312 | { |
313 | kfree(req->buf); | |
314 | usb_ep_free_request(ep, req); | |
315 | } | |
316 | ||
317 | /* | |
318 | * gs_send_packet | |
319 | * | |
320 | * If there is data to send, a packet is built in the given | |
321 | * buffer and the size is returned. If there is no data to | |
322 | * send, 0 is returned. | |
323 | * | |
324 | * Called with port_lock held. | |
325 | */ | |
326 | static unsigned | |
327 | gs_send_packet(struct gs_port *port, char *packet, unsigned size) | |
328 | { | |
329 | unsigned len; | |
330 | ||
331 | len = gs_buf_data_avail(&port->port_write_buf); | |
332 | if (len < size) | |
333 | size = len; | |
334 | if (size != 0) | |
335 | size = gs_buf_get(&port->port_write_buf, packet, size); | |
336 | return size; | |
337 | } | |
338 | ||
339 | /* | |
340 | * gs_start_tx | |
341 | * | |
342 | * This function finds available write requests, calls | |
343 | * gs_send_packet to fill these packets with data, and | |
344 | * continues until either there are no more write requests | |
345 | * available or no more data to send. This function is | |
346 | * run whenever data arrives or write requests are available. | |
347 | * | |
348 | * Context: caller owns port_lock; port_usb is non-null. | |
349 | */ | |
350 | static int gs_start_tx(struct gs_port *port) | |
351 | /* | |
352 | __releases(&port->port_lock) | |
353 | __acquires(&port->port_lock) | |
354 | */ | |
355 | { | |
356 | struct list_head *pool = &port->write_pool; | |
357 | struct usb_ep *in = port->port_usb->in; | |
358 | int status = 0; | |
359 | bool do_tty_wake = false; | |
360 | ||
361 | while (!list_empty(pool)) { | |
362 | struct usb_request *req; | |
363 | int len; | |
364 | ||
365 | req = list_entry(pool->next, struct usb_request, list); | |
366 | len = gs_send_packet(port, req->buf, in->maxpacket); | |
367 | if (len == 0) { | |
368 | wake_up_interruptible(&port->drain_wait); | |
369 | break; | |
370 | } | |
371 | do_tty_wake = true; | |
372 | ||
373 | req->length = len; | |
374 | list_del(&req->list); | |
2e251341 | 375 | req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0); |
c1dca562 | 376 | |
937ef73d DB |
377 | pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n", |
378 | port->port_num, len, *((u8 *)req->buf), | |
c1dca562 | 379 | *((u8 *)req->buf+1), *((u8 *)req->buf+2)); |
c1dca562 DB |
380 | |
381 | /* Drop lock while we call out of driver; completions | |
382 | * could be issued while we do so. Disconnection may | |
383 | * happen too; maybe immediately before we queue this! | |
384 | * | |
385 | * NOTE that we may keep sending data for a while after | |
386 | * the TTY closed (dev->ioport->port_tty is NULL). | |
387 | */ | |
388 | spin_unlock(&port->port_lock); | |
389 | status = usb_ep_queue(in, req, GFP_ATOMIC); | |
390 | spin_lock(&port->port_lock); | |
391 | ||
392 | if (status) { | |
393 | pr_debug("%s: %s %s err %d\n", | |
394 | __func__, "queue", in->name, status); | |
395 | list_add(&req->list, pool); | |
396 | break; | |
397 | } | |
398 | ||
399 | /* abort immediately after disconnect */ | |
400 | if (!port->port_usb) | |
401 | break; | |
402 | } | |
403 | ||
404 | if (do_tty_wake && port->port_tty) | |
405 | tty_wakeup(port->port_tty); | |
406 | return status; | |
407 | } | |
408 | ||
c1dca562 DB |
409 | /* |
410 | * Context: caller owns port_lock, and port_usb is set | |
411 | */ | |
412 | static unsigned gs_start_rx(struct gs_port *port) | |
413 | /* | |
414 | __releases(&port->port_lock) | |
415 | __acquires(&port->port_lock) | |
416 | */ | |
417 | { | |
418 | struct list_head *pool = &port->read_pool; | |
419 | struct usb_ep *out = port->port_usb->out; | |
420 | unsigned started = 0; | |
421 | ||
422 | while (!list_empty(pool)) { | |
423 | struct usb_request *req; | |
424 | int status; | |
425 | struct tty_struct *tty; | |
426 | ||
937ef73d | 427 | /* no more rx if closed */ |
c1dca562 | 428 | tty = port->port_tty; |
937ef73d | 429 | if (!tty) |
c1dca562 DB |
430 | break; |
431 | ||
432 | req = list_entry(pool->next, struct usb_request, list); | |
433 | list_del(&req->list); | |
434 | req->length = out->maxpacket; | |
435 | ||
436 | /* drop lock while we call out; the controller driver | |
437 | * may need to call us back (e.g. for disconnect) | |
438 | */ | |
439 | spin_unlock(&port->port_lock); | |
440 | status = usb_ep_queue(out, req, GFP_ATOMIC); | |
441 | spin_lock(&port->port_lock); | |
442 | ||
443 | if (status) { | |
444 | pr_debug("%s: %s %s err %d\n", | |
445 | __func__, "queue", out->name, status); | |
446 | list_add(&req->list, pool); | |
447 | break; | |
448 | } | |
449 | started++; | |
450 | ||
451 | /* abort immediately after disconnect */ | |
452 | if (!port->port_usb) | |
453 | break; | |
454 | } | |
455 | return started; | |
456 | } | |
457 | ||
937ef73d DB |
458 | /* |
459 | * RX tasklet takes data out of the RX queue and hands it up to the TTY | |
460 | * layer until it refuses to take any more data (or is throttled back). | |
461 | * Then it issues reads for any further data. | |
462 | * | |
463 | * If the RX queue becomes full enough that no usb_request is queued, | |
464 | * the OUT endpoint may begin NAKing as soon as its FIFO fills up. | |
465 | * So QUEUE_SIZE packets plus however many the FIFO holds (usually two) | |
466 | * can be buffered before the TTY layer's buffers (currently 64 KB). | |
467 | */ | |
468 | static void gs_rx_push(unsigned long _port) | |
c1dca562 | 469 | { |
937ef73d DB |
470 | struct gs_port *port = (void *)_port; |
471 | struct tty_struct *tty; | |
472 | struct list_head *queue = &port->read_queue; | |
473 | bool disconnect = false; | |
474 | bool do_push = false; | |
c1dca562 | 475 | |
937ef73d DB |
476 | /* hand any queued data to the tty */ |
477 | spin_lock_irq(&port->port_lock); | |
478 | tty = port->port_tty; | |
479 | while (!list_empty(queue)) { | |
480 | struct usb_request *req; | |
c1dca562 | 481 | |
937ef73d | 482 | req = list_first_entry(queue, struct usb_request, list); |
c1dca562 | 483 | |
937ef73d DB |
484 | /* discard data if tty was closed */ |
485 | if (!tty) | |
486 | goto recycle; | |
c1dca562 | 487 | |
937ef73d DB |
488 | /* leave data queued if tty was rx throttled */ |
489 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
490 | break; | |
491 | ||
492 | switch (req->status) { | |
493 | case -ESHUTDOWN: | |
494 | disconnect = true; | |
495 | pr_vdebug(PREFIX "%d: shutdown\n", port->port_num); | |
496 | break; | |
497 | ||
498 | default: | |
499 | /* presumably a transient fault */ | |
500 | pr_warning(PREFIX "%d: unexpected RX status %d\n", | |
501 | port->port_num, req->status); | |
502 | /* FALLTHROUGH */ | |
503 | case 0: | |
504 | /* normal completion */ | |
505 | break; | |
506 | } | |
507 | ||
508 | /* push data to (open) tty */ | |
509 | if (req->actual) { | |
510 | char *packet = req->buf; | |
511 | unsigned size = req->actual; | |
512 | unsigned n; | |
513 | int count; | |
514 | ||
515 | /* we may have pushed part of this packet already... */ | |
516 | n = port->n_read; | |
517 | if (n) { | |
518 | packet += n; | |
519 | size -= n; | |
520 | } | |
521 | ||
522 | count = tty_insert_flip_string(tty, packet, size); | |
523 | if (count) | |
524 | do_push = true; | |
525 | if (count != size) { | |
526 | /* stop pushing; TTY layer can't handle more */ | |
527 | port->n_read += count; | |
528 | pr_vdebug(PREFIX "%d: rx block %d/%d\n", | |
529 | port->port_num, | |
530 | count, req->actual); | |
531 | break; | |
532 | } | |
533 | port->n_read = 0; | |
534 | } | |
535 | recycle: | |
536 | list_move(&req->list, &port->read_pool); | |
537 | } | |
538 | ||
539 | /* Push from tty to ldisc; this is immediate with low_latency, and | |
540 | * may trigger callbacks to this driver ... so drop the spinlock. | |
541 | */ | |
542 | if (tty && do_push) { | |
543 | spin_unlock_irq(&port->port_lock); | |
544 | tty_flip_buffer_push(tty); | |
545 | wake_up_interruptible(&tty->read_wait); | |
546 | spin_lock_irq(&port->port_lock); | |
547 | ||
548 | /* tty may have been closed */ | |
549 | tty = port->port_tty; | |
c1dca562 | 550 | } |
937ef73d DB |
551 | |
552 | ||
553 | /* We want our data queue to become empty ASAP, keeping data | |
554 | * in the tty and ldisc (not here). If we couldn't push any | |
555 | * this time around, there may be trouble unless there's an | |
556 | * implicit tty_unthrottle() call on its way... | |
557 | * | |
558 | * REVISIT we should probably add a timer to keep the tasklet | |
559 | * from starving ... but it's not clear that case ever happens. | |
560 | */ | |
561 | if (!list_empty(queue) && tty) { | |
562 | if (!test_bit(TTY_THROTTLED, &tty->flags)) { | |
563 | if (do_push) | |
564 | tasklet_schedule(&port->push); | |
565 | else | |
566 | pr_warning(PREFIX "%d: RX not scheduled?\n", | |
567 | port->port_num); | |
568 | } | |
569 | } | |
570 | ||
571 | /* If we're still connected, refill the USB RX queue. */ | |
572 | if (!disconnect && port->port_usb) | |
573 | gs_start_rx(port); | |
574 | ||
575 | spin_unlock_irq(&port->port_lock); | |
576 | } | |
577 | ||
578 | static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) | |
579 | { | |
580 | struct gs_port *port = ep->driver_data; | |
581 | ||
582 | /* Queue all received data until the tty layer is ready for it. */ | |
583 | spin_lock(&port->port_lock); | |
584 | list_add_tail(&req->list, &port->read_queue); | |
585 | tasklet_schedule(&port->push); | |
c1dca562 DB |
586 | spin_unlock(&port->port_lock); |
587 | } | |
588 | ||
589 | static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) | |
590 | { | |
591 | struct gs_port *port = ep->driver_data; | |
592 | ||
593 | spin_lock(&port->port_lock); | |
594 | list_add(&req->list, &port->write_pool); | |
595 | ||
596 | switch (req->status) { | |
597 | default: | |
598 | /* presumably a transient fault */ | |
599 | pr_warning("%s: unexpected %s status %d\n", | |
600 | __func__, ep->name, req->status); | |
601 | /* FALL THROUGH */ | |
602 | case 0: | |
603 | /* normal completion */ | |
604 | gs_start_tx(port); | |
605 | break; | |
606 | ||
607 | case -ESHUTDOWN: | |
608 | /* disconnect */ | |
609 | pr_vdebug("%s: %s shutdown\n", __func__, ep->name); | |
610 | break; | |
611 | } | |
612 | ||
613 | spin_unlock(&port->port_lock); | |
614 | } | |
615 | ||
616 | static void gs_free_requests(struct usb_ep *ep, struct list_head *head) | |
617 | { | |
618 | struct usb_request *req; | |
619 | ||
620 | while (!list_empty(head)) { | |
621 | req = list_entry(head->next, struct usb_request, list); | |
622 | list_del(&req->list); | |
623 | gs_free_req(ep, req); | |
624 | } | |
625 | } | |
626 | ||
627 | static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, | |
628 | void (*fn)(struct usb_ep *, struct usb_request *)) | |
629 | { | |
630 | int i; | |
631 | struct usb_request *req; | |
632 | ||
633 | /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't | |
634 | * do quite that many this time, don't fail ... we just won't | |
635 | * be as speedy as we might otherwise be. | |
636 | */ | |
637 | for (i = 0; i < QUEUE_SIZE; i++) { | |
638 | req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); | |
639 | if (!req) | |
640 | return list_empty(head) ? -ENOMEM : 0; | |
641 | req->complete = fn; | |
642 | list_add_tail(&req->list, head); | |
643 | } | |
644 | return 0; | |
645 | } | |
646 | ||
647 | /** | |
648 | * gs_start_io - start USB I/O streams | |
649 | * @dev: encapsulates endpoints to use | |
650 | * Context: holding port_lock; port_tty and port_usb are non-null | |
651 | * | |
652 | * We only start I/O when something is connected to both sides of | |
653 | * this port. If nothing is listening on the host side, we may | |
654 | * be pointlessly filling up our TX buffers and FIFO. | |
655 | */ | |
656 | static int gs_start_io(struct gs_port *port) | |
657 | { | |
658 | struct list_head *head = &port->read_pool; | |
659 | struct usb_ep *ep = port->port_usb->out; | |
660 | int status; | |
661 | unsigned started; | |
662 | ||
663 | /* Allocate RX and TX I/O buffers. We can't easily do this much | |
664 | * earlier (with GFP_KERNEL) because the requests are coupled to | |
665 | * endpoints, as are the packet sizes we'll be using. Different | |
666 | * configurations may use different endpoints with a given port; | |
667 | * and high speed vs full speed changes packet sizes too. | |
668 | */ | |
669 | status = gs_alloc_requests(ep, head, gs_read_complete); | |
670 | if (status) | |
671 | return status; | |
672 | ||
673 | status = gs_alloc_requests(port->port_usb->in, &port->write_pool, | |
674 | gs_write_complete); | |
675 | if (status) { | |
676 | gs_free_requests(ep, head); | |
677 | return status; | |
678 | } | |
679 | ||
680 | /* queue read requests */ | |
937ef73d | 681 | port->n_read = 0; |
c1dca562 DB |
682 | started = gs_start_rx(port); |
683 | ||
684 | /* unblock any pending writes into our circular buffer */ | |
685 | if (started) { | |
686 | tty_wakeup(port->port_tty); | |
687 | } else { | |
688 | gs_free_requests(ep, head); | |
689 | gs_free_requests(port->port_usb->in, &port->write_pool); | |
937ef73d | 690 | status = -EIO; |
c1dca562 DB |
691 | } |
692 | ||
937ef73d | 693 | return status; |
c1dca562 DB |
694 | } |
695 | ||
696 | /*-------------------------------------------------------------------------*/ | |
697 | ||
698 | /* TTY Driver */ | |
699 | ||
700 | /* | |
701 | * gs_open sets up the link between a gs_port and its associated TTY. | |
702 | * That link is broken *only* by TTY close(), and all driver methods | |
703 | * know that. | |
704 | */ | |
705 | static int gs_open(struct tty_struct *tty, struct file *file) | |
706 | { | |
707 | int port_num = tty->index; | |
708 | struct gs_port *port; | |
709 | int status; | |
710 | ||
711 | if (port_num < 0 || port_num >= n_ports) | |
712 | return -ENXIO; | |
713 | ||
714 | do { | |
715 | mutex_lock(&ports[port_num].lock); | |
716 | port = ports[port_num].port; | |
717 | if (!port) | |
718 | status = -ENODEV; | |
719 | else { | |
720 | spin_lock_irq(&port->port_lock); | |
721 | ||
722 | /* already open? Great. */ | |
723 | if (port->open_count) { | |
724 | status = 0; | |
725 | port->open_count++; | |
726 | ||
727 | /* currently opening/closing? wait ... */ | |
728 | } else if (port->openclose) { | |
729 | status = -EBUSY; | |
730 | ||
731 | /* ... else we do the work */ | |
732 | } else { | |
733 | status = -EAGAIN; | |
734 | port->openclose = true; | |
735 | } | |
736 | spin_unlock_irq(&port->port_lock); | |
737 | } | |
738 | mutex_unlock(&ports[port_num].lock); | |
739 | ||
740 | switch (status) { | |
741 | default: | |
742 | /* fully handled */ | |
743 | return status; | |
744 | case -EAGAIN: | |
745 | /* must do the work */ | |
746 | break; | |
747 | case -EBUSY: | |
748 | /* wait for EAGAIN task to finish */ | |
749 | msleep(1); | |
750 | /* REVISIT could have a waitchannel here, if | |
751 | * concurrent open performance is important | |
752 | */ | |
753 | break; | |
754 | } | |
755 | } while (status != -EAGAIN); | |
756 | ||
757 | /* Do the "real open" */ | |
758 | spin_lock_irq(&port->port_lock); | |
759 | ||
760 | /* allocate circular buffer on first open */ | |
761 | if (port->port_write_buf.buf_buf == NULL) { | |
762 | ||
763 | spin_unlock_irq(&port->port_lock); | |
764 | status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE); | |
765 | spin_lock_irq(&port->port_lock); | |
766 | ||
767 | if (status) { | |
768 | pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n", | |
769 | port->port_num, tty, file); | |
770 | port->openclose = false; | |
771 | goto exit_unlock_port; | |
772 | } | |
773 | } | |
774 | ||
775 | /* REVISIT if REMOVED (ports[].port NULL), abort the open | |
776 | * to let rmmod work faster (but this way isn't wrong). | |
777 | */ | |
778 | ||
779 | /* REVISIT maybe wait for "carrier detect" */ | |
780 | ||
781 | tty->driver_data = port; | |
782 | port->port_tty = tty; | |
783 | ||
784 | port->open_count = 1; | |
785 | port->openclose = false; | |
786 | ||
787 | /* low_latency means ldiscs work in tasklet context, without | |
788 | * needing a workqueue schedule ... easier to keep up. | |
789 | */ | |
790 | tty->low_latency = 1; | |
791 | ||
792 | /* if connected, start the I/O stream */ | |
793 | if (port->port_usb) { | |
1f1ba11b DB |
794 | struct gserial *gser = port->port_usb; |
795 | ||
c1dca562 DB |
796 | pr_debug("gs_open: start ttyGS%d\n", port->port_num); |
797 | gs_start_io(port); | |
798 | ||
1f1ba11b DB |
799 | if (gser->connect) |
800 | gser->connect(gser); | |
c1dca562 DB |
801 | } |
802 | ||
803 | pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); | |
804 | ||
805 | status = 0; | |
806 | ||
807 | exit_unlock_port: | |
808 | spin_unlock_irq(&port->port_lock); | |
809 | return status; | |
810 | } | |
811 | ||
812 | static int gs_writes_finished(struct gs_port *p) | |
813 | { | |
814 | int cond; | |
815 | ||
816 | /* return true on disconnect or empty buffer */ | |
817 | spin_lock_irq(&p->port_lock); | |
818 | cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf); | |
819 | spin_unlock_irq(&p->port_lock); | |
820 | ||
821 | return cond; | |
822 | } | |
823 | ||
824 | static void gs_close(struct tty_struct *tty, struct file *file) | |
825 | { | |
826 | struct gs_port *port = tty->driver_data; | |
1f1ba11b | 827 | struct gserial *gser; |
c1dca562 DB |
828 | |
829 | spin_lock_irq(&port->port_lock); | |
830 | ||
831 | if (port->open_count != 1) { | |
832 | if (port->open_count == 0) | |
833 | WARN_ON(1); | |
834 | else | |
835 | --port->open_count; | |
836 | goto exit; | |
837 | } | |
838 | ||
839 | pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); | |
840 | ||
841 | /* mark port as closing but in use; we can drop port lock | |
842 | * and sleep if necessary | |
843 | */ | |
844 | port->openclose = true; | |
845 | port->open_count = 0; | |
846 | ||
1f1ba11b DB |
847 | gser = port->port_usb; |
848 | if (gser && gser->disconnect) | |
849 | gser->disconnect(gser); | |
c1dca562 DB |
850 | |
851 | /* wait for circular write buffer to drain, disconnect, or at | |
852 | * most GS_CLOSE_TIMEOUT seconds; then discard the rest | |
853 | */ | |
1f1ba11b | 854 | if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) { |
c1dca562 DB |
855 | spin_unlock_irq(&port->port_lock); |
856 | wait_event_interruptible_timeout(port->drain_wait, | |
857 | gs_writes_finished(port), | |
858 | GS_CLOSE_TIMEOUT * HZ); | |
859 | spin_lock_irq(&port->port_lock); | |
1f1ba11b | 860 | gser = port->port_usb; |
c1dca562 DB |
861 | } |
862 | ||
863 | /* Iff we're disconnected, there can be no I/O in flight so it's | |
864 | * ok to free the circular buffer; else just scrub it. And don't | |
865 | * let the push tasklet fire again until we're re-opened. | |
866 | */ | |
1f1ba11b | 867 | if (gser == NULL) |
c1dca562 DB |
868 | gs_buf_free(&port->port_write_buf); |
869 | else | |
870 | gs_buf_clear(&port->port_write_buf); | |
871 | ||
c1dca562 DB |
872 | tty->driver_data = NULL; |
873 | port->port_tty = NULL; | |
874 | ||
875 | port->openclose = false; | |
876 | ||
877 | pr_debug("gs_close: ttyGS%d (%p,%p) done!\n", | |
878 | port->port_num, tty, file); | |
879 | ||
880 | wake_up_interruptible(&port->close_wait); | |
881 | exit: | |
882 | spin_unlock_irq(&port->port_lock); | |
883 | } | |
884 | ||
885 | static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
886 | { | |
887 | struct gs_port *port = tty->driver_data; | |
888 | unsigned long flags; | |
889 | int status; | |
890 | ||
891 | pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n", | |
892 | port->port_num, tty, count); | |
893 | ||
894 | spin_lock_irqsave(&port->port_lock, flags); | |
895 | if (count) | |
896 | count = gs_buf_put(&port->port_write_buf, buf, count); | |
897 | /* treat count == 0 as flush_chars() */ | |
898 | if (port->port_usb) | |
899 | status = gs_start_tx(port); | |
900 | spin_unlock_irqrestore(&port->port_lock, flags); | |
901 | ||
902 | return count; | |
903 | } | |
904 | ||
905 | static int gs_put_char(struct tty_struct *tty, unsigned char ch) | |
906 | { | |
907 | struct gs_port *port = tty->driver_data; | |
908 | unsigned long flags; | |
909 | int status; | |
910 | ||
911 | pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %p\n", | |
912 | port->port_num, tty, ch, __builtin_return_address(0)); | |
913 | ||
914 | spin_lock_irqsave(&port->port_lock, flags); | |
915 | status = gs_buf_put(&port->port_write_buf, &ch, 1); | |
916 | spin_unlock_irqrestore(&port->port_lock, flags); | |
917 | ||
918 | return status; | |
919 | } | |
920 | ||
921 | static void gs_flush_chars(struct tty_struct *tty) | |
922 | { | |
923 | struct gs_port *port = tty->driver_data; | |
924 | unsigned long flags; | |
925 | ||
926 | pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty); | |
927 | ||
928 | spin_lock_irqsave(&port->port_lock, flags); | |
929 | if (port->port_usb) | |
930 | gs_start_tx(port); | |
931 | spin_unlock_irqrestore(&port->port_lock, flags); | |
932 | } | |
933 | ||
934 | static int gs_write_room(struct tty_struct *tty) | |
935 | { | |
936 | struct gs_port *port = tty->driver_data; | |
937 | unsigned long flags; | |
938 | int room = 0; | |
939 | ||
940 | spin_lock_irqsave(&port->port_lock, flags); | |
941 | if (port->port_usb) | |
942 | room = gs_buf_space_avail(&port->port_write_buf); | |
943 | spin_unlock_irqrestore(&port->port_lock, flags); | |
944 | ||
945 | pr_vdebug("gs_write_room: (%d,%p) room=%d\n", | |
946 | port->port_num, tty, room); | |
947 | ||
948 | return room; | |
949 | } | |
950 | ||
951 | static int gs_chars_in_buffer(struct tty_struct *tty) | |
952 | { | |
953 | struct gs_port *port = tty->driver_data; | |
954 | unsigned long flags; | |
955 | int chars = 0; | |
956 | ||
957 | spin_lock_irqsave(&port->port_lock, flags); | |
958 | chars = gs_buf_data_avail(&port->port_write_buf); | |
959 | spin_unlock_irqrestore(&port->port_lock, flags); | |
960 | ||
961 | pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n", | |
962 | port->port_num, tty, chars); | |
963 | ||
964 | return chars; | |
965 | } | |
966 | ||
967 | /* undo side effects of setting TTY_THROTTLED */ | |
968 | static void gs_unthrottle(struct tty_struct *tty) | |
969 | { | |
970 | struct gs_port *port = tty->driver_data; | |
971 | unsigned long flags; | |
c1dca562 DB |
972 | |
973 | spin_lock_irqsave(&port->port_lock, flags); | |
937ef73d DB |
974 | if (port->port_usb) { |
975 | /* Kickstart read queue processing. We don't do xon/xoff, | |
976 | * rts/cts, or other handshaking with the host, but if the | |
977 | * read queue backs up enough we'll be NAKing OUT packets. | |
978 | */ | |
979 | tasklet_schedule(&port->push); | |
980 | pr_vdebug(PREFIX "%d: unthrottle\n", port->port_num); | |
981 | } | |
c1dca562 | 982 | spin_unlock_irqrestore(&port->port_lock, flags); |
c1dca562 DB |
983 | } |
984 | ||
1f1ba11b DB |
985 | static int gs_break_ctl(struct tty_struct *tty, int duration) |
986 | { | |
987 | struct gs_port *port = tty->driver_data; | |
988 | int status = 0; | |
989 | struct gserial *gser; | |
990 | ||
991 | pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n", | |
992 | port->port_num, duration); | |
993 | ||
994 | spin_lock_irq(&port->port_lock); | |
995 | gser = port->port_usb; | |
996 | if (gser && gser->send_break) | |
997 | status = gser->send_break(gser, duration); | |
998 | spin_unlock_irq(&port->port_lock); | |
999 | ||
1000 | return status; | |
1001 | } | |
1002 | ||
c1dca562 DB |
1003 | static const struct tty_operations gs_tty_ops = { |
1004 | .open = gs_open, | |
1005 | .close = gs_close, | |
1006 | .write = gs_write, | |
1007 | .put_char = gs_put_char, | |
1008 | .flush_chars = gs_flush_chars, | |
1009 | .write_room = gs_write_room, | |
1010 | .chars_in_buffer = gs_chars_in_buffer, | |
1011 | .unthrottle = gs_unthrottle, | |
1f1ba11b | 1012 | .break_ctl = gs_break_ctl, |
c1dca562 DB |
1013 | }; |
1014 | ||
1015 | /*-------------------------------------------------------------------------*/ | |
1016 | ||
1017 | static struct tty_driver *gs_tty_driver; | |
1018 | ||
1019 | static int __init | |
1020 | gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) | |
1021 | { | |
1022 | struct gs_port *port; | |
1023 | ||
1024 | port = kzalloc(sizeof(struct gs_port), GFP_KERNEL); | |
1025 | if (port == NULL) | |
1026 | return -ENOMEM; | |
1027 | ||
1028 | spin_lock_init(&port->port_lock); | |
1029 | init_waitqueue_head(&port->close_wait); | |
1030 | init_waitqueue_head(&port->drain_wait); | |
1031 | ||
1032 | tasklet_init(&port->push, gs_rx_push, (unsigned long) port); | |
1033 | ||
1034 | INIT_LIST_HEAD(&port->read_pool); | |
937ef73d | 1035 | INIT_LIST_HEAD(&port->read_queue); |
c1dca562 DB |
1036 | INIT_LIST_HEAD(&port->write_pool); |
1037 | ||
1038 | port->port_num = port_num; | |
1039 | port->port_line_coding = *coding; | |
1040 | ||
1041 | ports[port_num].port = port; | |
1042 | ||
1043 | return 0; | |
1044 | } | |
1045 | ||
1046 | /** | |
1047 | * gserial_setup - initialize TTY driver for one or more ports | |
1048 | * @g: gadget to associate with these ports | |
1049 | * @count: how many ports to support | |
1050 | * Context: may sleep | |
1051 | * | |
1052 | * The TTY stack needs to know in advance how many devices it should | |
1053 | * plan to manage. Use this call to set up the ports you will be | |
1054 | * exporting through USB. Later, connect them to functions based | |
1055 | * on what configuration is activated by the USB host; and disconnect | |
1056 | * them as appropriate. | |
1057 | * | |
1058 | * An example would be a two-configuration device in which both | |
1059 | * configurations expose port 0, but through different functions. | |
1060 | * One configuration could even expose port 1 while the other | |
1061 | * one doesn't. | |
1062 | * | |
1063 | * Returns negative errno or zero. | |
1064 | */ | |
1065 | int __init gserial_setup(struct usb_gadget *g, unsigned count) | |
1066 | { | |
1067 | unsigned i; | |
1068 | struct usb_cdc_line_coding coding; | |
1069 | int status; | |
1070 | ||
1071 | if (count == 0 || count > N_PORTS) | |
1072 | return -EINVAL; | |
1073 | ||
1074 | gs_tty_driver = alloc_tty_driver(count); | |
1075 | if (!gs_tty_driver) | |
1076 | return -ENOMEM; | |
1077 | ||
1078 | gs_tty_driver->owner = THIS_MODULE; | |
1079 | gs_tty_driver->driver_name = "g_serial"; | |
937ef73d | 1080 | gs_tty_driver->name = PREFIX; |
c1dca562 DB |
1081 | /* uses dynamically assigned dev_t values */ |
1082 | ||
1083 | gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
1084 | gs_tty_driver->subtype = SERIAL_TYPE_NORMAL; | |
1085 | gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; | |
1086 | gs_tty_driver->init_termios = tty_std_termios; | |
1087 | ||
1088 | /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on | |
1089 | * MS-Windows. Otherwise, most of these flags shouldn't affect | |
1090 | * anything unless we were to actually hook up to a serial line. | |
1091 | */ | |
1092 | gs_tty_driver->init_termios.c_cflag = | |
1093 | B9600 | CS8 | CREAD | HUPCL | CLOCAL; | |
1094 | gs_tty_driver->init_termios.c_ispeed = 9600; | |
1095 | gs_tty_driver->init_termios.c_ospeed = 9600; | |
1096 | ||
551509d2 | 1097 | coding.dwDTERate = cpu_to_le32(9600); |
c1dca562 DB |
1098 | coding.bCharFormat = 8; |
1099 | coding.bParityType = USB_CDC_NO_PARITY; | |
1100 | coding.bDataBits = USB_CDC_1_STOP_BITS; | |
1101 | ||
1102 | tty_set_operations(gs_tty_driver, &gs_tty_ops); | |
1103 | ||
1104 | /* make devices be openable */ | |
1105 | for (i = 0; i < count; i++) { | |
1106 | mutex_init(&ports[i].lock); | |
1107 | status = gs_port_alloc(i, &coding); | |
1108 | if (status) { | |
1109 | count = i; | |
1110 | goto fail; | |
1111 | } | |
1112 | } | |
1113 | n_ports = count; | |
1114 | ||
1115 | /* export the driver ... */ | |
1116 | status = tty_register_driver(gs_tty_driver); | |
1117 | if (status) { | |
c1dca562 DB |
1118 | pr_err("%s: cannot register, err %d\n", |
1119 | __func__, status); | |
1120 | goto fail; | |
1121 | } | |
1122 | ||
1123 | /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */ | |
1124 | for (i = 0; i < count; i++) { | |
1125 | struct device *tty_dev; | |
1126 | ||
1127 | tty_dev = tty_register_device(gs_tty_driver, i, &g->dev); | |
1128 | if (IS_ERR(tty_dev)) | |
1129 | pr_warning("%s: no classdev for port %d, err %ld\n", | |
1130 | __func__, i, PTR_ERR(tty_dev)); | |
1131 | } | |
1132 | ||
1133 | pr_debug("%s: registered %d ttyGS* device%s\n", __func__, | |
1134 | count, (count == 1) ? "" : "s"); | |
1135 | ||
1136 | return status; | |
1137 | fail: | |
1138 | while (count--) | |
1139 | kfree(ports[count].port); | |
1140 | put_tty_driver(gs_tty_driver); | |
1141 | gs_tty_driver = NULL; | |
1142 | return status; | |
1143 | } | |
1144 | ||
1145 | static int gs_closed(struct gs_port *port) | |
1146 | { | |
1147 | int cond; | |
1148 | ||
1149 | spin_lock_irq(&port->port_lock); | |
1150 | cond = (port->open_count == 0) && !port->openclose; | |
1151 | spin_unlock_irq(&port->port_lock); | |
1152 | return cond; | |
1153 | } | |
1154 | ||
1155 | /** | |
1156 | * gserial_cleanup - remove TTY-over-USB driver and devices | |
1157 | * Context: may sleep | |
1158 | * | |
1159 | * This is called to free all resources allocated by @gserial_setup(). | |
1160 | * Accordingly, it may need to wait until some open /dev/ files have | |
1161 | * closed. | |
1162 | * | |
1163 | * The caller must have issued @gserial_disconnect() for any ports | |
1164 | * that had previously been connected, so that there is never any | |
1165 | * I/O pending when it's called. | |
1166 | */ | |
1167 | void gserial_cleanup(void) | |
1168 | { | |
1169 | unsigned i; | |
1170 | struct gs_port *port; | |
1171 | ||
ac90e365 DB |
1172 | if (!gs_tty_driver) |
1173 | return; | |
1174 | ||
c1dca562 DB |
1175 | /* start sysfs and /dev/ttyGS* node removal */ |
1176 | for (i = 0; i < n_ports; i++) | |
1177 | tty_unregister_device(gs_tty_driver, i); | |
1178 | ||
1179 | for (i = 0; i < n_ports; i++) { | |
1180 | /* prevent new opens */ | |
1181 | mutex_lock(&ports[i].lock); | |
1182 | port = ports[i].port; | |
1183 | ports[i].port = NULL; | |
1184 | mutex_unlock(&ports[i].lock); | |
1185 | ||
937ef73d DB |
1186 | tasklet_kill(&port->push); |
1187 | ||
c1dca562 DB |
1188 | /* wait for old opens to finish */ |
1189 | wait_event(port->close_wait, gs_closed(port)); | |
1190 | ||
1191 | WARN_ON(port->port_usb != NULL); | |
1192 | ||
1193 | kfree(port); | |
1194 | } | |
1195 | n_ports = 0; | |
1196 | ||
1197 | tty_unregister_driver(gs_tty_driver); | |
1198 | gs_tty_driver = NULL; | |
1199 | ||
1200 | pr_debug("%s: cleaned up ttyGS* support\n", __func__); | |
1201 | } | |
1202 | ||
1203 | /** | |
1204 | * gserial_connect - notify TTY I/O glue that USB link is active | |
1205 | * @gser: the function, set up with endpoints and descriptors | |
1206 | * @port_num: which port is active | |
1207 | * Context: any (usually from irq) | |
1208 | * | |
1209 | * This is called activate endpoints and let the TTY layer know that | |
1210 | * the connection is active ... not unlike "carrier detect". It won't | |
1211 | * necessarily start I/O queues; unless the TTY is held open by any | |
1212 | * task, there would be no point. However, the endpoints will be | |
1213 | * activated so the USB host can perform I/O, subject to basic USB | |
1214 | * hardware flow control. | |
1215 | * | |
1216 | * Caller needs to have set up the endpoints and USB function in @dev | |
1217 | * before calling this, as well as the appropriate (speed-specific) | |
1218 | * endpoint descriptors, and also have set up the TTY driver by calling | |
1219 | * @gserial_setup(). | |
1220 | * | |
1221 | * Returns negative errno or zero. | |
1222 | * On success, ep->driver_data will be overwritten. | |
1223 | */ | |
1224 | int gserial_connect(struct gserial *gser, u8 port_num) | |
1225 | { | |
1226 | struct gs_port *port; | |
1227 | unsigned long flags; | |
1228 | int status; | |
1229 | ||
1230 | if (!gs_tty_driver || port_num >= n_ports) | |
1231 | return -ENXIO; | |
1232 | ||
1233 | /* we "know" gserial_cleanup() hasn't been called */ | |
1234 | port = ports[port_num].port; | |
1235 | ||
1236 | /* activate the endpoints */ | |
1237 | status = usb_ep_enable(gser->in, gser->in_desc); | |
1238 | if (status < 0) | |
1239 | return status; | |
1240 | gser->in->driver_data = port; | |
1241 | ||
1242 | status = usb_ep_enable(gser->out, gser->out_desc); | |
1243 | if (status < 0) | |
1244 | goto fail_out; | |
1245 | gser->out->driver_data = port; | |
1246 | ||
1247 | /* then tell the tty glue that I/O can work */ | |
1248 | spin_lock_irqsave(&port->port_lock, flags); | |
1249 | gser->ioport = port; | |
1250 | port->port_usb = gser; | |
1251 | ||
1252 | /* REVISIT unclear how best to handle this state... | |
1253 | * we don't really couple it with the Linux TTY. | |
1254 | */ | |
1255 | gser->port_line_coding = port->port_line_coding; | |
1256 | ||
1257 | /* REVISIT if waiting on "carrier detect", signal. */ | |
1258 | ||
1f1ba11b DB |
1259 | /* if it's already open, start I/O ... and notify the serial |
1260 | * protocol about open/close status (connect/disconnect). | |
c1dca562 | 1261 | */ |
c1dca562 DB |
1262 | if (port->open_count) { |
1263 | pr_debug("gserial_connect: start ttyGS%d\n", port->port_num); | |
1264 | gs_start_io(port); | |
1f1ba11b DB |
1265 | if (gser->connect) |
1266 | gser->connect(gser); | |
1267 | } else { | |
1268 | if (gser->disconnect) | |
1269 | gser->disconnect(gser); | |
c1dca562 DB |
1270 | } |
1271 | ||
1272 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1273 | ||
1274 | return status; | |
1275 | ||
1276 | fail_out: | |
1277 | usb_ep_disable(gser->in); | |
1278 | gser->in->driver_data = NULL; | |
1279 | return status; | |
1280 | } | |
1281 | ||
1282 | /** | |
1283 | * gserial_disconnect - notify TTY I/O glue that USB link is inactive | |
1284 | * @gser: the function, on which gserial_connect() was called | |
1285 | * Context: any (usually from irq) | |
1286 | * | |
1287 | * This is called to deactivate endpoints and let the TTY layer know | |
1288 | * that the connection went inactive ... not unlike "hangup". | |
1289 | * | |
1290 | * On return, the state is as if gserial_connect() had never been called; | |
1291 | * there is no active USB I/O on these endpoints. | |
1292 | */ | |
1293 | void gserial_disconnect(struct gserial *gser) | |
1294 | { | |
1295 | struct gs_port *port = gser->ioport; | |
1296 | unsigned long flags; | |
1297 | ||
1298 | if (!port) | |
1299 | return; | |
1300 | ||
1301 | /* tell the TTY glue not to do I/O here any more */ | |
1302 | spin_lock_irqsave(&port->port_lock, flags); | |
1303 | ||
1304 | /* REVISIT as above: how best to track this? */ | |
1305 | port->port_line_coding = gser->port_line_coding; | |
1306 | ||
1307 | port->port_usb = NULL; | |
1308 | gser->ioport = NULL; | |
1309 | if (port->open_count > 0 || port->openclose) { | |
1310 | wake_up_interruptible(&port->drain_wait); | |
1311 | if (port->port_tty) | |
1312 | tty_hangup(port->port_tty); | |
1313 | } | |
1314 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1315 | ||
1316 | /* disable endpoints, aborting down any active I/O */ | |
1317 | usb_ep_disable(gser->out); | |
1318 | gser->out->driver_data = NULL; | |
1319 | ||
1320 | usb_ep_disable(gser->in); | |
1321 | gser->in->driver_data = NULL; | |
1322 | ||
1323 | /* finally, free any unused/unusable I/O buffers */ | |
1324 | spin_lock_irqsave(&port->port_lock, flags); | |
1325 | if (port->open_count == 0 && !port->openclose) | |
1326 | gs_buf_free(&port->port_write_buf); | |
1327 | gs_free_requests(gser->out, &port->read_pool); | |
937ef73d | 1328 | gs_free_requests(gser->out, &port->read_queue); |
c1dca562 DB |
1329 | gs_free_requests(gser->in, &port->write_pool); |
1330 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1331 | } |