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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> | |
26 | ||
27 | #include "u_serial.h" | |
28 | ||
29 | ||
30 | /* | |
31 | * This component encapsulates the TTY layer glue needed to provide basic | |
32 | * "serial port" functionality through the USB gadget stack. Each such | |
33 | * port is exposed through a /dev/ttyGS* node. | |
34 | * | |
35 | * After initialization (gserial_setup), these TTY port devices stay | |
36 | * available until they are removed (gserial_cleanup). Each one may be | |
37 | * connected to a USB function (gserial_connect), or disconnected (with | |
38 | * gserial_disconnect) when the USB host issues a config change event. | |
39 | * Data can only flow when the port is connected to the host. | |
40 | * | |
41 | * A given TTY port can be made available in multiple configurations. | |
42 | * For example, each one might expose a ttyGS0 node which provides a | |
43 | * login application. In one case that might use CDC ACM interface 0, | |
44 | * while another configuration might use interface 3 for that. The | |
45 | * work to handle that (including descriptor management) is not part | |
46 | * of this component. | |
47 | * | |
48 | * Configurations may expose more than one TTY port. For example, if | |
49 | * ttyGS0 provides login service, then ttyGS1 might provide dialer access | |
50 | * for a telephone or fax link. And ttyGS2 might be something that just | |
51 | * needs a simple byte stream interface for some messaging protocol that | |
52 | * is managed in userspace ... OBEX, PTP, and MTP have been mentioned. | |
53 | */ | |
54 | ||
937ef73d DB |
55 | #define PREFIX "ttyGS" |
56 | ||
c1dca562 DB |
57 | /* |
58 | * gserial is the lifecycle interface, used by USB functions | |
59 | * gs_port is the I/O nexus, used by the tty driver | |
60 | * tty_struct links to the tty/filesystem framework | |
61 | * | |
62 | * gserial <---> gs_port ... links will be null when the USB link is | |
1f1ba11b DB |
63 | * inactive; managed by gserial_{connect,disconnect}(). each gserial |
64 | * instance can wrap its own USB control protocol. | |
c1dca562 DB |
65 | * gserial->ioport == usb_ep->driver_data ... gs_port |
66 | * gs_port->port_usb ... gserial | |
67 | * | |
68 | * gs_port <---> tty_struct ... links will be null when the TTY file | |
69 | * isn't opened; managed by gs_open()/gs_close() | |
70 | * gserial->port_tty ... tty_struct | |
71 | * tty_struct->driver_data ... gserial | |
72 | */ | |
73 | ||
74 | /* RX and TX queues can buffer QUEUE_SIZE packets before they hit the | |
75 | * next layer of buffering. For TX that's a circular buffer; for RX | |
76 | * consider it a NOP. A third layer is provided by the TTY code. | |
77 | */ | |
78 | #define QUEUE_SIZE 16 | |
79 | #define WRITE_BUF_SIZE 8192 /* TX only */ | |
80 | ||
81 | /* circular buffer */ | |
82 | struct gs_buf { | |
83 | unsigned buf_size; | |
84 | char *buf_buf; | |
85 | char *buf_get; | |
86 | char *buf_put; | |
87 | }; | |
88 | ||
89 | /* | |
90 | * The port structure holds info for each port, one for each minor number | |
91 | * (and thus for each /dev/ node). | |
92 | */ | |
93 | struct gs_port { | |
94 | spinlock_t port_lock; /* guard port_* access */ | |
95 | ||
96 | struct gserial *port_usb; | |
97 | struct tty_struct *port_tty; | |
98 | ||
99 | unsigned open_count; | |
100 | bool openclose; /* open/close in progress */ | |
101 | u8 port_num; | |
102 | ||
103 | wait_queue_head_t close_wait; /* wait for last close */ | |
104 | ||
105 | struct list_head read_pool; | |
937ef73d DB |
106 | struct list_head read_queue; |
107 | unsigned n_read; | |
c1dca562 DB |
108 | struct tasklet_struct push; |
109 | ||
110 | struct list_head write_pool; | |
111 | struct gs_buf port_write_buf; | |
112 | wait_queue_head_t drain_wait; /* wait while writes drain */ | |
113 | ||
114 | /* REVISIT this state ... */ | |
115 | struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */ | |
116 | }; | |
117 | ||
118 | /* increase N_PORTS if you need more */ | |
119 | #define N_PORTS 4 | |
120 | static struct portmaster { | |
121 | struct mutex lock; /* protect open/close */ | |
122 | struct gs_port *port; | |
123 | } ports[N_PORTS]; | |
124 | static unsigned n_ports; | |
125 | ||
126 | #define GS_CLOSE_TIMEOUT 15 /* seconds */ | |
127 | ||
128 | ||
129 | ||
130 | #ifdef VERBOSE_DEBUG | |
131 | #define pr_vdebug(fmt, arg...) \ | |
132 | pr_debug(fmt, ##arg) | |
133 | #else | |
134 | #define pr_vdebug(fmt, arg...) \ | |
135 | ({ if (0) pr_debug(fmt, ##arg); }) | |
136 | #endif | |
137 | ||
138 | /*-------------------------------------------------------------------------*/ | |
139 | ||
140 | /* Circular Buffer */ | |
141 | ||
142 | /* | |
143 | * gs_buf_alloc | |
144 | * | |
145 | * Allocate a circular buffer and all associated memory. | |
146 | */ | |
147 | static int gs_buf_alloc(struct gs_buf *gb, unsigned size) | |
148 | { | |
149 | gb->buf_buf = kmalloc(size, GFP_KERNEL); | |
150 | if (gb->buf_buf == NULL) | |
151 | return -ENOMEM; | |
152 | ||
153 | gb->buf_size = size; | |
154 | gb->buf_put = gb->buf_buf; | |
155 | gb->buf_get = gb->buf_buf; | |
156 | ||
157 | return 0; | |
158 | } | |
159 | ||
160 | /* | |
161 | * gs_buf_free | |
162 | * | |
163 | * Free the buffer and all associated memory. | |
164 | */ | |
165 | static void gs_buf_free(struct gs_buf *gb) | |
166 | { | |
167 | kfree(gb->buf_buf); | |
168 | gb->buf_buf = NULL; | |
169 | } | |
170 | ||
171 | /* | |
172 | * gs_buf_clear | |
173 | * | |
174 | * Clear out all data in the circular buffer. | |
175 | */ | |
176 | static void gs_buf_clear(struct gs_buf *gb) | |
177 | { | |
178 | gb->buf_get = gb->buf_put; | |
179 | /* equivalent to a get of all data available */ | |
180 | } | |
181 | ||
182 | /* | |
183 | * gs_buf_data_avail | |
184 | * | |
1f1ba11b | 185 | * Return the number of bytes of data written into the circular |
c1dca562 DB |
186 | * buffer. |
187 | */ | |
188 | static unsigned gs_buf_data_avail(struct gs_buf *gb) | |
189 | { | |
190 | return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size; | |
191 | } | |
192 | ||
193 | /* | |
194 | * gs_buf_space_avail | |
195 | * | |
196 | * Return the number of bytes of space available in the circular | |
197 | * buffer. | |
198 | */ | |
199 | static unsigned gs_buf_space_avail(struct gs_buf *gb) | |
200 | { | |
201 | return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size; | |
202 | } | |
203 | ||
204 | /* | |
205 | * gs_buf_put | |
206 | * | |
207 | * Copy data data from a user buffer and put it into the circular buffer. | |
208 | * Restrict to the amount of space available. | |
209 | * | |
210 | * Return the number of bytes copied. | |
211 | */ | |
212 | static unsigned | |
213 | gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count) | |
214 | { | |
215 | unsigned len; | |
216 | ||
217 | len = gs_buf_space_avail(gb); | |
218 | if (count > len) | |
219 | count = len; | |
220 | ||
221 | if (count == 0) | |
222 | return 0; | |
223 | ||
224 | len = gb->buf_buf + gb->buf_size - gb->buf_put; | |
225 | if (count > len) { | |
226 | memcpy(gb->buf_put, buf, len); | |
227 | memcpy(gb->buf_buf, buf+len, count - len); | |
228 | gb->buf_put = gb->buf_buf + count - len; | |
229 | } else { | |
230 | memcpy(gb->buf_put, buf, count); | |
231 | if (count < len) | |
232 | gb->buf_put += count; | |
233 | else /* count == len */ | |
234 | gb->buf_put = gb->buf_buf; | |
235 | } | |
236 | ||
237 | return count; | |
238 | } | |
239 | ||
240 | /* | |
241 | * gs_buf_get | |
242 | * | |
243 | * Get data from the circular buffer and copy to the given buffer. | |
244 | * Restrict to the amount of data available. | |
245 | * | |
246 | * Return the number of bytes copied. | |
247 | */ | |
248 | static unsigned | |
249 | gs_buf_get(struct gs_buf *gb, char *buf, unsigned count) | |
250 | { | |
251 | unsigned len; | |
252 | ||
253 | len = gs_buf_data_avail(gb); | |
254 | if (count > len) | |
255 | count = len; | |
256 | ||
257 | if (count == 0) | |
258 | return 0; | |
259 | ||
260 | len = gb->buf_buf + gb->buf_size - gb->buf_get; | |
261 | if (count > len) { | |
262 | memcpy(buf, gb->buf_get, len); | |
263 | memcpy(buf+len, gb->buf_buf, count - len); | |
264 | gb->buf_get = gb->buf_buf + count - len; | |
265 | } else { | |
266 | memcpy(buf, gb->buf_get, count); | |
267 | if (count < len) | |
268 | gb->buf_get += count; | |
269 | else /* count == len */ | |
270 | gb->buf_get = gb->buf_buf; | |
271 | } | |
272 | ||
273 | return count; | |
274 | } | |
275 | ||
276 | /*-------------------------------------------------------------------------*/ | |
277 | ||
278 | /* I/O glue between TTY (upper) and USB function (lower) driver layers */ | |
279 | ||
280 | /* | |
281 | * gs_alloc_req | |
282 | * | |
283 | * Allocate a usb_request and its buffer. Returns a pointer to the | |
284 | * usb_request or NULL if there is an error. | |
285 | */ | |
1f1ba11b | 286 | struct usb_request * |
c1dca562 DB |
287 | gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) |
288 | { | |
289 | struct usb_request *req; | |
290 | ||
291 | req = usb_ep_alloc_request(ep, kmalloc_flags); | |
292 | ||
293 | if (req != NULL) { | |
294 | req->length = len; | |
295 | req->buf = kmalloc(len, kmalloc_flags); | |
296 | if (req->buf == NULL) { | |
297 | usb_ep_free_request(ep, req); | |
298 | return NULL; | |
299 | } | |
300 | } | |
301 | ||
302 | return req; | |
303 | } | |
304 | ||
305 | /* | |
306 | * gs_free_req | |
307 | * | |
308 | * Free a usb_request and its buffer. | |
309 | */ | |
1f1ba11b | 310 | void gs_free_req(struct usb_ep *ep, struct usb_request *req) |
c1dca562 DB |
311 | { |
312 | kfree(req->buf); | |
313 | usb_ep_free_request(ep, req); | |
314 | } | |
315 | ||
316 | /* | |
317 | * gs_send_packet | |
318 | * | |
319 | * If there is data to send, a packet is built in the given | |
320 | * buffer and the size is returned. If there is no data to | |
321 | * send, 0 is returned. | |
322 | * | |
323 | * Called with port_lock held. | |
324 | */ | |
325 | static unsigned | |
326 | gs_send_packet(struct gs_port *port, char *packet, unsigned size) | |
327 | { | |
328 | unsigned len; | |
329 | ||
330 | len = gs_buf_data_avail(&port->port_write_buf); | |
331 | if (len < size) | |
332 | size = len; | |
333 | if (size != 0) | |
334 | size = gs_buf_get(&port->port_write_buf, packet, size); | |
335 | return size; | |
336 | } | |
337 | ||
338 | /* | |
339 | * gs_start_tx | |
340 | * | |
341 | * This function finds available write requests, calls | |
342 | * gs_send_packet to fill these packets with data, and | |
343 | * continues until either there are no more write requests | |
344 | * available or no more data to send. This function is | |
345 | * run whenever data arrives or write requests are available. | |
346 | * | |
347 | * Context: caller owns port_lock; port_usb is non-null. | |
348 | */ | |
349 | static int gs_start_tx(struct gs_port *port) | |
350 | /* | |
351 | __releases(&port->port_lock) | |
352 | __acquires(&port->port_lock) | |
353 | */ | |
354 | { | |
355 | struct list_head *pool = &port->write_pool; | |
356 | struct usb_ep *in = port->port_usb->in; | |
357 | int status = 0; | |
358 | bool do_tty_wake = false; | |
359 | ||
360 | while (!list_empty(pool)) { | |
361 | struct usb_request *req; | |
362 | int len; | |
363 | ||
364 | req = list_entry(pool->next, struct usb_request, list); | |
365 | len = gs_send_packet(port, req->buf, in->maxpacket); | |
366 | if (len == 0) { | |
367 | wake_up_interruptible(&port->drain_wait); | |
368 | break; | |
369 | } | |
370 | do_tty_wake = true; | |
371 | ||
372 | req->length = len; | |
373 | list_del(&req->list); | |
374 | ||
937ef73d DB |
375 | pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n", |
376 | port->port_num, len, *((u8 *)req->buf), | |
c1dca562 | 377 | *((u8 *)req->buf+1), *((u8 *)req->buf+2)); |
c1dca562 DB |
378 | |
379 | /* Drop lock while we call out of driver; completions | |
380 | * could be issued while we do so. Disconnection may | |
381 | * happen too; maybe immediately before we queue this! | |
382 | * | |
383 | * NOTE that we may keep sending data for a while after | |
384 | * the TTY closed (dev->ioport->port_tty is NULL). | |
385 | */ | |
386 | spin_unlock(&port->port_lock); | |
387 | status = usb_ep_queue(in, req, GFP_ATOMIC); | |
388 | spin_lock(&port->port_lock); | |
389 | ||
390 | if (status) { | |
391 | pr_debug("%s: %s %s err %d\n", | |
392 | __func__, "queue", in->name, status); | |
393 | list_add(&req->list, pool); | |
394 | break; | |
395 | } | |
396 | ||
397 | /* abort immediately after disconnect */ | |
398 | if (!port->port_usb) | |
399 | break; | |
400 | } | |
401 | ||
402 | if (do_tty_wake && port->port_tty) | |
403 | tty_wakeup(port->port_tty); | |
404 | return status; | |
405 | } | |
406 | ||
c1dca562 DB |
407 | /* |
408 | * Context: caller owns port_lock, and port_usb is set | |
409 | */ | |
410 | static unsigned gs_start_rx(struct gs_port *port) | |
411 | /* | |
412 | __releases(&port->port_lock) | |
413 | __acquires(&port->port_lock) | |
414 | */ | |
415 | { | |
416 | struct list_head *pool = &port->read_pool; | |
417 | struct usb_ep *out = port->port_usb->out; | |
418 | unsigned started = 0; | |
419 | ||
420 | while (!list_empty(pool)) { | |
421 | struct usb_request *req; | |
422 | int status; | |
423 | struct tty_struct *tty; | |
424 | ||
937ef73d | 425 | /* no more rx if closed */ |
c1dca562 | 426 | tty = port->port_tty; |
937ef73d | 427 | if (!tty) |
c1dca562 DB |
428 | break; |
429 | ||
430 | req = list_entry(pool->next, struct usb_request, list); | |
431 | list_del(&req->list); | |
432 | req->length = out->maxpacket; | |
433 | ||
434 | /* drop lock while we call out; the controller driver | |
435 | * may need to call us back (e.g. for disconnect) | |
436 | */ | |
437 | spin_unlock(&port->port_lock); | |
438 | status = usb_ep_queue(out, req, GFP_ATOMIC); | |
439 | spin_lock(&port->port_lock); | |
440 | ||
441 | if (status) { | |
442 | pr_debug("%s: %s %s err %d\n", | |
443 | __func__, "queue", out->name, status); | |
444 | list_add(&req->list, pool); | |
445 | break; | |
446 | } | |
447 | started++; | |
448 | ||
449 | /* abort immediately after disconnect */ | |
450 | if (!port->port_usb) | |
451 | break; | |
452 | } | |
453 | return started; | |
454 | } | |
455 | ||
937ef73d DB |
456 | /* |
457 | * RX tasklet takes data out of the RX queue and hands it up to the TTY | |
458 | * layer until it refuses to take any more data (or is throttled back). | |
459 | * Then it issues reads for any further data. | |
460 | * | |
461 | * If the RX queue becomes full enough that no usb_request is queued, | |
462 | * the OUT endpoint may begin NAKing as soon as its FIFO fills up. | |
463 | * So QUEUE_SIZE packets plus however many the FIFO holds (usually two) | |
464 | * can be buffered before the TTY layer's buffers (currently 64 KB). | |
465 | */ | |
466 | static void gs_rx_push(unsigned long _port) | |
c1dca562 | 467 | { |
937ef73d DB |
468 | struct gs_port *port = (void *)_port; |
469 | struct tty_struct *tty; | |
470 | struct list_head *queue = &port->read_queue; | |
471 | bool disconnect = false; | |
472 | bool do_push = false; | |
c1dca562 | 473 | |
937ef73d DB |
474 | /* hand any queued data to the tty */ |
475 | spin_lock_irq(&port->port_lock); | |
476 | tty = port->port_tty; | |
477 | while (!list_empty(queue)) { | |
478 | struct usb_request *req; | |
c1dca562 | 479 | |
937ef73d | 480 | req = list_first_entry(queue, struct usb_request, list); |
c1dca562 | 481 | |
937ef73d DB |
482 | /* discard data if tty was closed */ |
483 | if (!tty) | |
484 | goto recycle; | |
c1dca562 | 485 | |
937ef73d DB |
486 | /* leave data queued if tty was rx throttled */ |
487 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
488 | break; | |
489 | ||
490 | switch (req->status) { | |
491 | case -ESHUTDOWN: | |
492 | disconnect = true; | |
493 | pr_vdebug(PREFIX "%d: shutdown\n", port->port_num); | |
494 | break; | |
495 | ||
496 | default: | |
497 | /* presumably a transient fault */ | |
498 | pr_warning(PREFIX "%d: unexpected RX status %d\n", | |
499 | port->port_num, req->status); | |
500 | /* FALLTHROUGH */ | |
501 | case 0: | |
502 | /* normal completion */ | |
503 | break; | |
504 | } | |
505 | ||
506 | /* push data to (open) tty */ | |
507 | if (req->actual) { | |
508 | char *packet = req->buf; | |
509 | unsigned size = req->actual; | |
510 | unsigned n; | |
511 | int count; | |
512 | ||
513 | /* we may have pushed part of this packet already... */ | |
514 | n = port->n_read; | |
515 | if (n) { | |
516 | packet += n; | |
517 | size -= n; | |
518 | } | |
519 | ||
520 | count = tty_insert_flip_string(tty, packet, size); | |
521 | if (count) | |
522 | do_push = true; | |
523 | if (count != size) { | |
524 | /* stop pushing; TTY layer can't handle more */ | |
525 | port->n_read += count; | |
526 | pr_vdebug(PREFIX "%d: rx block %d/%d\n", | |
527 | port->port_num, | |
528 | count, req->actual); | |
529 | break; | |
530 | } | |
531 | port->n_read = 0; | |
532 | } | |
533 | recycle: | |
534 | list_move(&req->list, &port->read_pool); | |
535 | } | |
536 | ||
537 | /* Push from tty to ldisc; this is immediate with low_latency, and | |
538 | * may trigger callbacks to this driver ... so drop the spinlock. | |
539 | */ | |
540 | if (tty && do_push) { | |
541 | spin_unlock_irq(&port->port_lock); | |
542 | tty_flip_buffer_push(tty); | |
543 | wake_up_interruptible(&tty->read_wait); | |
544 | spin_lock_irq(&port->port_lock); | |
545 | ||
546 | /* tty may have been closed */ | |
547 | tty = port->port_tty; | |
c1dca562 | 548 | } |
937ef73d DB |
549 | |
550 | ||
551 | /* We want our data queue to become empty ASAP, keeping data | |
552 | * in the tty and ldisc (not here). If we couldn't push any | |
553 | * this time around, there may be trouble unless there's an | |
554 | * implicit tty_unthrottle() call on its way... | |
555 | * | |
556 | * REVISIT we should probably add a timer to keep the tasklet | |
557 | * from starving ... but it's not clear that case ever happens. | |
558 | */ | |
559 | if (!list_empty(queue) && tty) { | |
560 | if (!test_bit(TTY_THROTTLED, &tty->flags)) { | |
561 | if (do_push) | |
562 | tasklet_schedule(&port->push); | |
563 | else | |
564 | pr_warning(PREFIX "%d: RX not scheduled?\n", | |
565 | port->port_num); | |
566 | } | |
567 | } | |
568 | ||
569 | /* If we're still connected, refill the USB RX queue. */ | |
570 | if (!disconnect && port->port_usb) | |
571 | gs_start_rx(port); | |
572 | ||
573 | spin_unlock_irq(&port->port_lock); | |
574 | } | |
575 | ||
576 | static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) | |
577 | { | |
578 | struct gs_port *port = ep->driver_data; | |
579 | ||
580 | /* Queue all received data until the tty layer is ready for it. */ | |
581 | spin_lock(&port->port_lock); | |
582 | list_add_tail(&req->list, &port->read_queue); | |
583 | tasklet_schedule(&port->push); | |
c1dca562 DB |
584 | spin_unlock(&port->port_lock); |
585 | } | |
586 | ||
587 | static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) | |
588 | { | |
589 | struct gs_port *port = ep->driver_data; | |
590 | ||
591 | spin_lock(&port->port_lock); | |
592 | list_add(&req->list, &port->write_pool); | |
593 | ||
594 | switch (req->status) { | |
595 | default: | |
596 | /* presumably a transient fault */ | |
597 | pr_warning("%s: unexpected %s status %d\n", | |
598 | __func__, ep->name, req->status); | |
599 | /* FALL THROUGH */ | |
600 | case 0: | |
601 | /* normal completion */ | |
602 | gs_start_tx(port); | |
603 | break; | |
604 | ||
605 | case -ESHUTDOWN: | |
606 | /* disconnect */ | |
607 | pr_vdebug("%s: %s shutdown\n", __func__, ep->name); | |
608 | break; | |
609 | } | |
610 | ||
611 | spin_unlock(&port->port_lock); | |
612 | } | |
613 | ||
614 | static void gs_free_requests(struct usb_ep *ep, struct list_head *head) | |
615 | { | |
616 | struct usb_request *req; | |
617 | ||
618 | while (!list_empty(head)) { | |
619 | req = list_entry(head->next, struct usb_request, list); | |
620 | list_del(&req->list); | |
621 | gs_free_req(ep, req); | |
622 | } | |
623 | } | |
624 | ||
625 | static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, | |
626 | void (*fn)(struct usb_ep *, struct usb_request *)) | |
627 | { | |
628 | int i; | |
629 | struct usb_request *req; | |
630 | ||
631 | /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't | |
632 | * do quite that many this time, don't fail ... we just won't | |
633 | * be as speedy as we might otherwise be. | |
634 | */ | |
635 | for (i = 0; i < QUEUE_SIZE; i++) { | |
636 | req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); | |
637 | if (!req) | |
638 | return list_empty(head) ? -ENOMEM : 0; | |
639 | req->complete = fn; | |
640 | list_add_tail(&req->list, head); | |
641 | } | |
642 | return 0; | |
643 | } | |
644 | ||
645 | /** | |
646 | * gs_start_io - start USB I/O streams | |
647 | * @dev: encapsulates endpoints to use | |
648 | * Context: holding port_lock; port_tty and port_usb are non-null | |
649 | * | |
650 | * We only start I/O when something is connected to both sides of | |
651 | * this port. If nothing is listening on the host side, we may | |
652 | * be pointlessly filling up our TX buffers and FIFO. | |
653 | */ | |
654 | static int gs_start_io(struct gs_port *port) | |
655 | { | |
656 | struct list_head *head = &port->read_pool; | |
657 | struct usb_ep *ep = port->port_usb->out; | |
658 | int status; | |
659 | unsigned started; | |
660 | ||
661 | /* Allocate RX and TX I/O buffers. We can't easily do this much | |
662 | * earlier (with GFP_KERNEL) because the requests are coupled to | |
663 | * endpoints, as are the packet sizes we'll be using. Different | |
664 | * configurations may use different endpoints with a given port; | |
665 | * and high speed vs full speed changes packet sizes too. | |
666 | */ | |
667 | status = gs_alloc_requests(ep, head, gs_read_complete); | |
668 | if (status) | |
669 | return status; | |
670 | ||
671 | status = gs_alloc_requests(port->port_usb->in, &port->write_pool, | |
672 | gs_write_complete); | |
673 | if (status) { | |
674 | gs_free_requests(ep, head); | |
675 | return status; | |
676 | } | |
677 | ||
678 | /* queue read requests */ | |
937ef73d | 679 | port->n_read = 0; |
c1dca562 DB |
680 | started = gs_start_rx(port); |
681 | ||
682 | /* unblock any pending writes into our circular buffer */ | |
683 | if (started) { | |
684 | tty_wakeup(port->port_tty); | |
685 | } else { | |
686 | gs_free_requests(ep, head); | |
687 | gs_free_requests(port->port_usb->in, &port->write_pool); | |
937ef73d | 688 | status = -EIO; |
c1dca562 DB |
689 | } |
690 | ||
937ef73d | 691 | return status; |
c1dca562 DB |
692 | } |
693 | ||
694 | /*-------------------------------------------------------------------------*/ | |
695 | ||
696 | /* TTY Driver */ | |
697 | ||
698 | /* | |
699 | * gs_open sets up the link between a gs_port and its associated TTY. | |
700 | * That link is broken *only* by TTY close(), and all driver methods | |
701 | * know that. | |
702 | */ | |
703 | static int gs_open(struct tty_struct *tty, struct file *file) | |
704 | { | |
705 | int port_num = tty->index; | |
706 | struct gs_port *port; | |
707 | int status; | |
708 | ||
709 | if (port_num < 0 || port_num >= n_ports) | |
710 | return -ENXIO; | |
711 | ||
712 | do { | |
713 | mutex_lock(&ports[port_num].lock); | |
714 | port = ports[port_num].port; | |
715 | if (!port) | |
716 | status = -ENODEV; | |
717 | else { | |
718 | spin_lock_irq(&port->port_lock); | |
719 | ||
720 | /* already open? Great. */ | |
721 | if (port->open_count) { | |
722 | status = 0; | |
723 | port->open_count++; | |
724 | ||
725 | /* currently opening/closing? wait ... */ | |
726 | } else if (port->openclose) { | |
727 | status = -EBUSY; | |
728 | ||
729 | /* ... else we do the work */ | |
730 | } else { | |
731 | status = -EAGAIN; | |
732 | port->openclose = true; | |
733 | } | |
734 | spin_unlock_irq(&port->port_lock); | |
735 | } | |
736 | mutex_unlock(&ports[port_num].lock); | |
737 | ||
738 | switch (status) { | |
739 | default: | |
740 | /* fully handled */ | |
741 | return status; | |
742 | case -EAGAIN: | |
743 | /* must do the work */ | |
744 | break; | |
745 | case -EBUSY: | |
746 | /* wait for EAGAIN task to finish */ | |
747 | msleep(1); | |
748 | /* REVISIT could have a waitchannel here, if | |
749 | * concurrent open performance is important | |
750 | */ | |
751 | break; | |
752 | } | |
753 | } while (status != -EAGAIN); | |
754 | ||
755 | /* Do the "real open" */ | |
756 | spin_lock_irq(&port->port_lock); | |
757 | ||
758 | /* allocate circular buffer on first open */ | |
759 | if (port->port_write_buf.buf_buf == NULL) { | |
760 | ||
761 | spin_unlock_irq(&port->port_lock); | |
762 | status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE); | |
763 | spin_lock_irq(&port->port_lock); | |
764 | ||
765 | if (status) { | |
766 | pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n", | |
767 | port->port_num, tty, file); | |
768 | port->openclose = false; | |
769 | goto exit_unlock_port; | |
770 | } | |
771 | } | |
772 | ||
773 | /* REVISIT if REMOVED (ports[].port NULL), abort the open | |
774 | * to let rmmod work faster (but this way isn't wrong). | |
775 | */ | |
776 | ||
777 | /* REVISIT maybe wait for "carrier detect" */ | |
778 | ||
779 | tty->driver_data = port; | |
780 | port->port_tty = tty; | |
781 | ||
782 | port->open_count = 1; | |
783 | port->openclose = false; | |
784 | ||
785 | /* low_latency means ldiscs work in tasklet context, without | |
786 | * needing a workqueue schedule ... easier to keep up. | |
787 | */ | |
788 | tty->low_latency = 1; | |
789 | ||
790 | /* if connected, start the I/O stream */ | |
791 | if (port->port_usb) { | |
1f1ba11b DB |
792 | struct gserial *gser = port->port_usb; |
793 | ||
c1dca562 DB |
794 | pr_debug("gs_open: start ttyGS%d\n", port->port_num); |
795 | gs_start_io(port); | |
796 | ||
1f1ba11b DB |
797 | if (gser->connect) |
798 | gser->connect(gser); | |
c1dca562 DB |
799 | } |
800 | ||
801 | pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); | |
802 | ||
803 | status = 0; | |
804 | ||
805 | exit_unlock_port: | |
806 | spin_unlock_irq(&port->port_lock); | |
807 | return status; | |
808 | } | |
809 | ||
810 | static int gs_writes_finished(struct gs_port *p) | |
811 | { | |
812 | int cond; | |
813 | ||
814 | /* return true on disconnect or empty buffer */ | |
815 | spin_lock_irq(&p->port_lock); | |
816 | cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf); | |
817 | spin_unlock_irq(&p->port_lock); | |
818 | ||
819 | return cond; | |
820 | } | |
821 | ||
822 | static void gs_close(struct tty_struct *tty, struct file *file) | |
823 | { | |
824 | struct gs_port *port = tty->driver_data; | |
1f1ba11b | 825 | struct gserial *gser; |
c1dca562 DB |
826 | |
827 | spin_lock_irq(&port->port_lock); | |
828 | ||
829 | if (port->open_count != 1) { | |
830 | if (port->open_count == 0) | |
831 | WARN_ON(1); | |
832 | else | |
833 | --port->open_count; | |
834 | goto exit; | |
835 | } | |
836 | ||
837 | pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); | |
838 | ||
839 | /* mark port as closing but in use; we can drop port lock | |
840 | * and sleep if necessary | |
841 | */ | |
842 | port->openclose = true; | |
843 | port->open_count = 0; | |
844 | ||
1f1ba11b DB |
845 | gser = port->port_usb; |
846 | if (gser && gser->disconnect) | |
847 | gser->disconnect(gser); | |
c1dca562 DB |
848 | |
849 | /* wait for circular write buffer to drain, disconnect, or at | |
850 | * most GS_CLOSE_TIMEOUT seconds; then discard the rest | |
851 | */ | |
1f1ba11b | 852 | if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) { |
c1dca562 DB |
853 | spin_unlock_irq(&port->port_lock); |
854 | wait_event_interruptible_timeout(port->drain_wait, | |
855 | gs_writes_finished(port), | |
856 | GS_CLOSE_TIMEOUT * HZ); | |
857 | spin_lock_irq(&port->port_lock); | |
1f1ba11b | 858 | gser = port->port_usb; |
c1dca562 DB |
859 | } |
860 | ||
861 | /* Iff we're disconnected, there can be no I/O in flight so it's | |
862 | * ok to free the circular buffer; else just scrub it. And don't | |
863 | * let the push tasklet fire again until we're re-opened. | |
864 | */ | |
1f1ba11b | 865 | if (gser == NULL) |
c1dca562 DB |
866 | gs_buf_free(&port->port_write_buf); |
867 | else | |
868 | gs_buf_clear(&port->port_write_buf); | |
869 | ||
c1dca562 DB |
870 | tty->driver_data = NULL; |
871 | port->port_tty = NULL; | |
872 | ||
873 | port->openclose = false; | |
874 | ||
875 | pr_debug("gs_close: ttyGS%d (%p,%p) done!\n", | |
876 | port->port_num, tty, file); | |
877 | ||
878 | wake_up_interruptible(&port->close_wait); | |
879 | exit: | |
880 | spin_unlock_irq(&port->port_lock); | |
881 | } | |
882 | ||
883 | static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
884 | { | |
885 | struct gs_port *port = tty->driver_data; | |
886 | unsigned long flags; | |
887 | int status; | |
888 | ||
889 | pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n", | |
890 | port->port_num, tty, count); | |
891 | ||
892 | spin_lock_irqsave(&port->port_lock, flags); | |
893 | if (count) | |
894 | count = gs_buf_put(&port->port_write_buf, buf, count); | |
895 | /* treat count == 0 as flush_chars() */ | |
896 | if (port->port_usb) | |
897 | status = gs_start_tx(port); | |
898 | spin_unlock_irqrestore(&port->port_lock, flags); | |
899 | ||
900 | return count; | |
901 | } | |
902 | ||
903 | static int gs_put_char(struct tty_struct *tty, unsigned char ch) | |
904 | { | |
905 | struct gs_port *port = tty->driver_data; | |
906 | unsigned long flags; | |
907 | int status; | |
908 | ||
909 | pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %p\n", | |
910 | port->port_num, tty, ch, __builtin_return_address(0)); | |
911 | ||
912 | spin_lock_irqsave(&port->port_lock, flags); | |
913 | status = gs_buf_put(&port->port_write_buf, &ch, 1); | |
914 | spin_unlock_irqrestore(&port->port_lock, flags); | |
915 | ||
916 | return status; | |
917 | } | |
918 | ||
919 | static void gs_flush_chars(struct tty_struct *tty) | |
920 | { | |
921 | struct gs_port *port = tty->driver_data; | |
922 | unsigned long flags; | |
923 | ||
924 | pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty); | |
925 | ||
926 | spin_lock_irqsave(&port->port_lock, flags); | |
927 | if (port->port_usb) | |
928 | gs_start_tx(port); | |
929 | spin_unlock_irqrestore(&port->port_lock, flags); | |
930 | } | |
931 | ||
932 | static int gs_write_room(struct tty_struct *tty) | |
933 | { | |
934 | struct gs_port *port = tty->driver_data; | |
935 | unsigned long flags; | |
936 | int room = 0; | |
937 | ||
938 | spin_lock_irqsave(&port->port_lock, flags); | |
939 | if (port->port_usb) | |
940 | room = gs_buf_space_avail(&port->port_write_buf); | |
941 | spin_unlock_irqrestore(&port->port_lock, flags); | |
942 | ||
943 | pr_vdebug("gs_write_room: (%d,%p) room=%d\n", | |
944 | port->port_num, tty, room); | |
945 | ||
946 | return room; | |
947 | } | |
948 | ||
949 | static int gs_chars_in_buffer(struct tty_struct *tty) | |
950 | { | |
951 | struct gs_port *port = tty->driver_data; | |
952 | unsigned long flags; | |
953 | int chars = 0; | |
954 | ||
955 | spin_lock_irqsave(&port->port_lock, flags); | |
956 | chars = gs_buf_data_avail(&port->port_write_buf); | |
957 | spin_unlock_irqrestore(&port->port_lock, flags); | |
958 | ||
959 | pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n", | |
960 | port->port_num, tty, chars); | |
961 | ||
962 | return chars; | |
963 | } | |
964 | ||
965 | /* undo side effects of setting TTY_THROTTLED */ | |
966 | static void gs_unthrottle(struct tty_struct *tty) | |
967 | { | |
968 | struct gs_port *port = tty->driver_data; | |
969 | unsigned long flags; | |
c1dca562 DB |
970 | |
971 | spin_lock_irqsave(&port->port_lock, flags); | |
937ef73d DB |
972 | if (port->port_usb) { |
973 | /* Kickstart read queue processing. We don't do xon/xoff, | |
974 | * rts/cts, or other handshaking with the host, but if the | |
975 | * read queue backs up enough we'll be NAKing OUT packets. | |
976 | */ | |
977 | tasklet_schedule(&port->push); | |
978 | pr_vdebug(PREFIX "%d: unthrottle\n", port->port_num); | |
979 | } | |
c1dca562 | 980 | spin_unlock_irqrestore(&port->port_lock, flags); |
c1dca562 DB |
981 | } |
982 | ||
1f1ba11b DB |
983 | static int gs_break_ctl(struct tty_struct *tty, int duration) |
984 | { | |
985 | struct gs_port *port = tty->driver_data; | |
986 | int status = 0; | |
987 | struct gserial *gser; | |
988 | ||
989 | pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n", | |
990 | port->port_num, duration); | |
991 | ||
992 | spin_lock_irq(&port->port_lock); | |
993 | gser = port->port_usb; | |
994 | if (gser && gser->send_break) | |
995 | status = gser->send_break(gser, duration); | |
996 | spin_unlock_irq(&port->port_lock); | |
997 | ||
998 | return status; | |
999 | } | |
1000 | ||
c1dca562 DB |
1001 | static const struct tty_operations gs_tty_ops = { |
1002 | .open = gs_open, | |
1003 | .close = gs_close, | |
1004 | .write = gs_write, | |
1005 | .put_char = gs_put_char, | |
1006 | .flush_chars = gs_flush_chars, | |
1007 | .write_room = gs_write_room, | |
1008 | .chars_in_buffer = gs_chars_in_buffer, | |
1009 | .unthrottle = gs_unthrottle, | |
1f1ba11b | 1010 | .break_ctl = gs_break_ctl, |
c1dca562 DB |
1011 | }; |
1012 | ||
1013 | /*-------------------------------------------------------------------------*/ | |
1014 | ||
1015 | static struct tty_driver *gs_tty_driver; | |
1016 | ||
1017 | static int __init | |
1018 | gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) | |
1019 | { | |
1020 | struct gs_port *port; | |
1021 | ||
1022 | port = kzalloc(sizeof(struct gs_port), GFP_KERNEL); | |
1023 | if (port == NULL) | |
1024 | return -ENOMEM; | |
1025 | ||
1026 | spin_lock_init(&port->port_lock); | |
1027 | init_waitqueue_head(&port->close_wait); | |
1028 | init_waitqueue_head(&port->drain_wait); | |
1029 | ||
1030 | tasklet_init(&port->push, gs_rx_push, (unsigned long) port); | |
1031 | ||
1032 | INIT_LIST_HEAD(&port->read_pool); | |
937ef73d | 1033 | INIT_LIST_HEAD(&port->read_queue); |
c1dca562 DB |
1034 | INIT_LIST_HEAD(&port->write_pool); |
1035 | ||
1036 | port->port_num = port_num; | |
1037 | port->port_line_coding = *coding; | |
1038 | ||
1039 | ports[port_num].port = port; | |
1040 | ||
1041 | return 0; | |
1042 | } | |
1043 | ||
1044 | /** | |
1045 | * gserial_setup - initialize TTY driver for one or more ports | |
1046 | * @g: gadget to associate with these ports | |
1047 | * @count: how many ports to support | |
1048 | * Context: may sleep | |
1049 | * | |
1050 | * The TTY stack needs to know in advance how many devices it should | |
1051 | * plan to manage. Use this call to set up the ports you will be | |
1052 | * exporting through USB. Later, connect them to functions based | |
1053 | * on what configuration is activated by the USB host; and disconnect | |
1054 | * them as appropriate. | |
1055 | * | |
1056 | * An example would be a two-configuration device in which both | |
1057 | * configurations expose port 0, but through different functions. | |
1058 | * One configuration could even expose port 1 while the other | |
1059 | * one doesn't. | |
1060 | * | |
1061 | * Returns negative errno or zero. | |
1062 | */ | |
1063 | int __init gserial_setup(struct usb_gadget *g, unsigned count) | |
1064 | { | |
1065 | unsigned i; | |
1066 | struct usb_cdc_line_coding coding; | |
1067 | int status; | |
1068 | ||
1069 | if (count == 0 || count > N_PORTS) | |
1070 | return -EINVAL; | |
1071 | ||
1072 | gs_tty_driver = alloc_tty_driver(count); | |
1073 | if (!gs_tty_driver) | |
1074 | return -ENOMEM; | |
1075 | ||
1076 | gs_tty_driver->owner = THIS_MODULE; | |
1077 | gs_tty_driver->driver_name = "g_serial"; | |
937ef73d | 1078 | gs_tty_driver->name = PREFIX; |
c1dca562 DB |
1079 | /* uses dynamically assigned dev_t values */ |
1080 | ||
1081 | gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
1082 | gs_tty_driver->subtype = SERIAL_TYPE_NORMAL; | |
1083 | gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; | |
1084 | gs_tty_driver->init_termios = tty_std_termios; | |
1085 | ||
1086 | /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on | |
1087 | * MS-Windows. Otherwise, most of these flags shouldn't affect | |
1088 | * anything unless we were to actually hook up to a serial line. | |
1089 | */ | |
1090 | gs_tty_driver->init_termios.c_cflag = | |
1091 | B9600 | CS8 | CREAD | HUPCL | CLOCAL; | |
1092 | gs_tty_driver->init_termios.c_ispeed = 9600; | |
1093 | gs_tty_driver->init_termios.c_ospeed = 9600; | |
1094 | ||
1095 | coding.dwDTERate = __constant_cpu_to_le32(9600); | |
1096 | coding.bCharFormat = 8; | |
1097 | coding.bParityType = USB_CDC_NO_PARITY; | |
1098 | coding.bDataBits = USB_CDC_1_STOP_BITS; | |
1099 | ||
1100 | tty_set_operations(gs_tty_driver, &gs_tty_ops); | |
1101 | ||
1102 | /* make devices be openable */ | |
1103 | for (i = 0; i < count; i++) { | |
1104 | mutex_init(&ports[i].lock); | |
1105 | status = gs_port_alloc(i, &coding); | |
1106 | if (status) { | |
1107 | count = i; | |
1108 | goto fail; | |
1109 | } | |
1110 | } | |
1111 | n_ports = count; | |
1112 | ||
1113 | /* export the driver ... */ | |
1114 | status = tty_register_driver(gs_tty_driver); | |
1115 | if (status) { | |
1116 | put_tty_driver(gs_tty_driver); | |
1117 | pr_err("%s: cannot register, err %d\n", | |
1118 | __func__, status); | |
1119 | goto fail; | |
1120 | } | |
1121 | ||
1122 | /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */ | |
1123 | for (i = 0; i < count; i++) { | |
1124 | struct device *tty_dev; | |
1125 | ||
1126 | tty_dev = tty_register_device(gs_tty_driver, i, &g->dev); | |
1127 | if (IS_ERR(tty_dev)) | |
1128 | pr_warning("%s: no classdev for port %d, err %ld\n", | |
1129 | __func__, i, PTR_ERR(tty_dev)); | |
1130 | } | |
1131 | ||
1132 | pr_debug("%s: registered %d ttyGS* device%s\n", __func__, | |
1133 | count, (count == 1) ? "" : "s"); | |
1134 | ||
1135 | return status; | |
1136 | fail: | |
1137 | while (count--) | |
1138 | kfree(ports[count].port); | |
1139 | put_tty_driver(gs_tty_driver); | |
1140 | gs_tty_driver = NULL; | |
1141 | return status; | |
1142 | } | |
1143 | ||
1144 | static int gs_closed(struct gs_port *port) | |
1145 | { | |
1146 | int cond; | |
1147 | ||
1148 | spin_lock_irq(&port->port_lock); | |
1149 | cond = (port->open_count == 0) && !port->openclose; | |
1150 | spin_unlock_irq(&port->port_lock); | |
1151 | return cond; | |
1152 | } | |
1153 | ||
1154 | /** | |
1155 | * gserial_cleanup - remove TTY-over-USB driver and devices | |
1156 | * Context: may sleep | |
1157 | * | |
1158 | * This is called to free all resources allocated by @gserial_setup(). | |
1159 | * Accordingly, it may need to wait until some open /dev/ files have | |
1160 | * closed. | |
1161 | * | |
1162 | * The caller must have issued @gserial_disconnect() for any ports | |
1163 | * that had previously been connected, so that there is never any | |
1164 | * I/O pending when it's called. | |
1165 | */ | |
1166 | void gserial_cleanup(void) | |
1167 | { | |
1168 | unsigned i; | |
1169 | struct gs_port *port; | |
1170 | ||
ac90e365 DB |
1171 | if (!gs_tty_driver) |
1172 | return; | |
1173 | ||
c1dca562 DB |
1174 | /* start sysfs and /dev/ttyGS* node removal */ |
1175 | for (i = 0; i < n_ports; i++) | |
1176 | tty_unregister_device(gs_tty_driver, i); | |
1177 | ||
1178 | for (i = 0; i < n_ports; i++) { | |
1179 | /* prevent new opens */ | |
1180 | mutex_lock(&ports[i].lock); | |
1181 | port = ports[i].port; | |
1182 | ports[i].port = NULL; | |
1183 | mutex_unlock(&ports[i].lock); | |
1184 | ||
937ef73d DB |
1185 | tasklet_kill(&port->push); |
1186 | ||
c1dca562 DB |
1187 | /* wait for old opens to finish */ |
1188 | wait_event(port->close_wait, gs_closed(port)); | |
1189 | ||
1190 | WARN_ON(port->port_usb != NULL); | |
1191 | ||
1192 | kfree(port); | |
1193 | } | |
1194 | n_ports = 0; | |
1195 | ||
1196 | tty_unregister_driver(gs_tty_driver); | |
1197 | gs_tty_driver = NULL; | |
1198 | ||
1199 | pr_debug("%s: cleaned up ttyGS* support\n", __func__); | |
1200 | } | |
1201 | ||
1202 | /** | |
1203 | * gserial_connect - notify TTY I/O glue that USB link is active | |
1204 | * @gser: the function, set up with endpoints and descriptors | |
1205 | * @port_num: which port is active | |
1206 | * Context: any (usually from irq) | |
1207 | * | |
1208 | * This is called activate endpoints and let the TTY layer know that | |
1209 | * the connection is active ... not unlike "carrier detect". It won't | |
1210 | * necessarily start I/O queues; unless the TTY is held open by any | |
1211 | * task, there would be no point. However, the endpoints will be | |
1212 | * activated so the USB host can perform I/O, subject to basic USB | |
1213 | * hardware flow control. | |
1214 | * | |
1215 | * Caller needs to have set up the endpoints and USB function in @dev | |
1216 | * before calling this, as well as the appropriate (speed-specific) | |
1217 | * endpoint descriptors, and also have set up the TTY driver by calling | |
1218 | * @gserial_setup(). | |
1219 | * | |
1220 | * Returns negative errno or zero. | |
1221 | * On success, ep->driver_data will be overwritten. | |
1222 | */ | |
1223 | int gserial_connect(struct gserial *gser, u8 port_num) | |
1224 | { | |
1225 | struct gs_port *port; | |
1226 | unsigned long flags; | |
1227 | int status; | |
1228 | ||
1229 | if (!gs_tty_driver || port_num >= n_ports) | |
1230 | return -ENXIO; | |
1231 | ||
1232 | /* we "know" gserial_cleanup() hasn't been called */ | |
1233 | port = ports[port_num].port; | |
1234 | ||
1235 | /* activate the endpoints */ | |
1236 | status = usb_ep_enable(gser->in, gser->in_desc); | |
1237 | if (status < 0) | |
1238 | return status; | |
1239 | gser->in->driver_data = port; | |
1240 | ||
1241 | status = usb_ep_enable(gser->out, gser->out_desc); | |
1242 | if (status < 0) | |
1243 | goto fail_out; | |
1244 | gser->out->driver_data = port; | |
1245 | ||
1246 | /* then tell the tty glue that I/O can work */ | |
1247 | spin_lock_irqsave(&port->port_lock, flags); | |
1248 | gser->ioport = port; | |
1249 | port->port_usb = gser; | |
1250 | ||
1251 | /* REVISIT unclear how best to handle this state... | |
1252 | * we don't really couple it with the Linux TTY. | |
1253 | */ | |
1254 | gser->port_line_coding = port->port_line_coding; | |
1255 | ||
1256 | /* REVISIT if waiting on "carrier detect", signal. */ | |
1257 | ||
1f1ba11b DB |
1258 | /* if it's already open, start I/O ... and notify the serial |
1259 | * protocol about open/close status (connect/disconnect). | |
c1dca562 | 1260 | */ |
c1dca562 DB |
1261 | if (port->open_count) { |
1262 | pr_debug("gserial_connect: start ttyGS%d\n", port->port_num); | |
1263 | gs_start_io(port); | |
1f1ba11b DB |
1264 | if (gser->connect) |
1265 | gser->connect(gser); | |
1266 | } else { | |
1267 | if (gser->disconnect) | |
1268 | gser->disconnect(gser); | |
c1dca562 DB |
1269 | } |
1270 | ||
1271 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1272 | ||
1273 | return status; | |
1274 | ||
1275 | fail_out: | |
1276 | usb_ep_disable(gser->in); | |
1277 | gser->in->driver_data = NULL; | |
1278 | return status; | |
1279 | } | |
1280 | ||
1281 | /** | |
1282 | * gserial_disconnect - notify TTY I/O glue that USB link is inactive | |
1283 | * @gser: the function, on which gserial_connect() was called | |
1284 | * Context: any (usually from irq) | |
1285 | * | |
1286 | * This is called to deactivate endpoints and let the TTY layer know | |
1287 | * that the connection went inactive ... not unlike "hangup". | |
1288 | * | |
1289 | * On return, the state is as if gserial_connect() had never been called; | |
1290 | * there is no active USB I/O on these endpoints. | |
1291 | */ | |
1292 | void gserial_disconnect(struct gserial *gser) | |
1293 | { | |
1294 | struct gs_port *port = gser->ioport; | |
1295 | unsigned long flags; | |
1296 | ||
1297 | if (!port) | |
1298 | return; | |
1299 | ||
1300 | /* tell the TTY glue not to do I/O here any more */ | |
1301 | spin_lock_irqsave(&port->port_lock, flags); | |
1302 | ||
1303 | /* REVISIT as above: how best to track this? */ | |
1304 | port->port_line_coding = gser->port_line_coding; | |
1305 | ||
1306 | port->port_usb = NULL; | |
1307 | gser->ioport = NULL; | |
1308 | if (port->open_count > 0 || port->openclose) { | |
1309 | wake_up_interruptible(&port->drain_wait); | |
1310 | if (port->port_tty) | |
1311 | tty_hangup(port->port_tty); | |
1312 | } | |
1313 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1314 | ||
1315 | /* disable endpoints, aborting down any active I/O */ | |
1316 | usb_ep_disable(gser->out); | |
1317 | gser->out->driver_data = NULL; | |
1318 | ||
1319 | usb_ep_disable(gser->in); | |
1320 | gser->in->driver_data = NULL; | |
1321 | ||
1322 | /* finally, free any unused/unusable I/O buffers */ | |
1323 | spin_lock_irqsave(&port->port_lock, flags); | |
1324 | if (port->open_count == 0 && !port->openclose) | |
1325 | gs_buf_free(&port->port_write_buf); | |
1326 | gs_free_requests(gser->out, &port->read_pool); | |
937ef73d | 1327 | gs_free_requests(gser->out, &port->read_queue); |
c1dca562 DB |
1328 | gs_free_requests(gser->in, &port->write_pool); |
1329 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1330 | } |