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e220ff75 SAS |
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/sched.h> | |
22 | #include <linux/interrupt.h> | |
23 | #include <linux/device.h> | |
24 | #include <linux/delay.h> | |
25 | #include <linux/tty.h> | |
26 | #include <linux/tty_flip.h> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/export.h> | |
29 | ||
30 | #include "u_serial.h" | |
31 | ||
32 | ||
33 | /* | |
34 | * This component encapsulates the TTY layer glue needed to provide basic | |
35 | * "serial port" functionality through the USB gadget stack. Each such | |
36 | * port is exposed through a /dev/ttyGS* node. | |
37 | * | |
38 | * After initialization (gserial_setup), these TTY port devices stay | |
39 | * available until they are removed (gserial_cleanup). Each one may be | |
40 | * connected to a USB function (gserial_connect), or disconnected (with | |
41 | * gserial_disconnect) when the USB host issues a config change event. | |
42 | * Data can only flow when the port is connected to the host. | |
43 | * | |
44 | * A given TTY port can be made available in multiple configurations. | |
45 | * For example, each one might expose a ttyGS0 node which provides a | |
46 | * login application. In one case that might use CDC ACM interface 0, | |
47 | * while another configuration might use interface 3 for that. The | |
48 | * work to handle that (including descriptor management) is not part | |
49 | * of this component. | |
50 | * | |
51 | * Configurations may expose more than one TTY port. For example, if | |
52 | * ttyGS0 provides login service, then ttyGS1 might provide dialer access | |
53 | * for a telephone or fax link. And ttyGS2 might be something that just | |
54 | * needs a simple byte stream interface for some messaging protocol that | |
55 | * is managed in userspace ... OBEX, PTP, and MTP have been mentioned. | |
56 | */ | |
57 | ||
58 | #define PREFIX "ttyGS" | |
59 | ||
60 | /* | |
61 | * gserial is the lifecycle interface, used by USB functions | |
62 | * gs_port is the I/O nexus, used by the tty driver | |
63 | * tty_struct links to the tty/filesystem framework | |
64 | * | |
65 | * gserial <---> gs_port ... links will be null when the USB link is | |
66 | * inactive; managed by gserial_{connect,disconnect}(). each gserial | |
67 | * instance can wrap its own USB control protocol. | |
68 | * gserial->ioport == usb_ep->driver_data ... gs_port | |
69 | * gs_port->port_usb ... gserial | |
70 | * | |
71 | * gs_port <---> tty_struct ... links will be null when the TTY file | |
72 | * isn't opened; managed by gs_open()/gs_close() | |
73 | * gserial->port_tty ... tty_struct | |
74 | * tty_struct->driver_data ... gserial | |
75 | */ | |
76 | ||
77 | /* RX and TX queues can buffer QUEUE_SIZE packets before they hit the | |
78 | * next layer of buffering. For TX that's a circular buffer; for RX | |
79 | * consider it a NOP. A third layer is provided by the TTY code. | |
80 | */ | |
81 | #define QUEUE_SIZE 16 | |
82 | #define WRITE_BUF_SIZE 8192 /* TX only */ | |
83 | ||
84 | /* circular buffer */ | |
85 | struct gs_buf { | |
86 | unsigned buf_size; | |
87 | char *buf_buf; | |
88 | char *buf_get; | |
89 | char *buf_put; | |
90 | }; | |
91 | ||
92 | /* | |
93 | * The port structure holds info for each port, one for each minor number | |
94 | * (and thus for each /dev/ node). | |
95 | */ | |
96 | struct gs_port { | |
97 | struct tty_port port; | |
98 | spinlock_t port_lock; /* guard port_* access */ | |
99 | ||
100 | struct gserial *port_usb; | |
101 | ||
102 | bool openclose; /* open/close in progress */ | |
103 | u8 port_num; | |
104 | ||
105 | struct list_head read_pool; | |
106 | int read_started; | |
107 | int read_allocated; | |
108 | struct list_head read_queue; | |
109 | unsigned n_read; | |
110 | struct tasklet_struct push; | |
111 | ||
112 | struct list_head write_pool; | |
113 | int write_started; | |
114 | int write_allocated; | |
115 | struct gs_buf port_write_buf; | |
116 | wait_queue_head_t drain_wait; /* wait while writes drain */ | |
117 | ||
118 | /* REVISIT this state ... */ | |
119 | struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */ | |
120 | }; | |
121 | ||
122 | /* increase N_PORTS if you need more */ | |
123 | #define N_PORTS 4 | |
124 | static struct portmaster { | |
125 | struct mutex lock; /* protect open/close */ | |
126 | struct gs_port *port; | |
127 | } ports[N_PORTS]; | |
128 | static unsigned n_ports; | |
129 | ||
130 | #define GS_CLOSE_TIMEOUT 15 /* seconds */ | |
131 | ||
132 | ||
133 | ||
134 | #ifdef VERBOSE_DEBUG | |
135 | #define pr_vdebug(fmt, arg...) \ | |
136 | pr_debug(fmt, ##arg) | |
137 | #else | |
138 | #define pr_vdebug(fmt, arg...) \ | |
139 | ({ if (0) pr_debug(fmt, ##arg); }) | |
140 | #endif | |
141 | ||
142 | /*-------------------------------------------------------------------------*/ | |
143 | ||
144 | /* Circular Buffer */ | |
145 | ||
146 | /* | |
147 | * gs_buf_alloc | |
148 | * | |
149 | * Allocate a circular buffer and all associated memory. | |
150 | */ | |
151 | static int gs_buf_alloc(struct gs_buf *gb, unsigned size) | |
152 | { | |
153 | gb->buf_buf = kmalloc(size, GFP_KERNEL); | |
154 | if (gb->buf_buf == NULL) | |
155 | return -ENOMEM; | |
156 | ||
157 | gb->buf_size = size; | |
158 | gb->buf_put = gb->buf_buf; | |
159 | gb->buf_get = gb->buf_buf; | |
160 | ||
161 | return 0; | |
162 | } | |
163 | ||
164 | /* | |
165 | * gs_buf_free | |
166 | * | |
167 | * Free the buffer and all associated memory. | |
168 | */ | |
169 | static void gs_buf_free(struct gs_buf *gb) | |
170 | { | |
171 | kfree(gb->buf_buf); | |
172 | gb->buf_buf = NULL; | |
173 | } | |
174 | ||
175 | /* | |
176 | * gs_buf_clear | |
177 | * | |
178 | * Clear out all data in the circular buffer. | |
179 | */ | |
180 | static void gs_buf_clear(struct gs_buf *gb) | |
181 | { | |
182 | gb->buf_get = gb->buf_put; | |
183 | /* equivalent to a get of all data available */ | |
184 | } | |
185 | ||
186 | /* | |
187 | * gs_buf_data_avail | |
188 | * | |
189 | * Return the number of bytes of data written into the circular | |
190 | * buffer. | |
191 | */ | |
192 | static unsigned gs_buf_data_avail(struct gs_buf *gb) | |
193 | { | |
194 | return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size; | |
195 | } | |
196 | ||
197 | /* | |
198 | * gs_buf_space_avail | |
199 | * | |
200 | * Return the number of bytes of space available in the circular | |
201 | * buffer. | |
202 | */ | |
203 | static unsigned gs_buf_space_avail(struct gs_buf *gb) | |
204 | { | |
205 | return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size; | |
206 | } | |
207 | ||
208 | /* | |
209 | * gs_buf_put | |
210 | * | |
211 | * Copy data data from a user buffer and put it into the circular buffer. | |
212 | * Restrict to the amount of space available. | |
213 | * | |
214 | * Return the number of bytes copied. | |
215 | */ | |
216 | static unsigned | |
217 | gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count) | |
218 | { | |
219 | unsigned len; | |
220 | ||
221 | len = gs_buf_space_avail(gb); | |
222 | if (count > len) | |
223 | count = len; | |
224 | ||
225 | if (count == 0) | |
226 | return 0; | |
227 | ||
228 | len = gb->buf_buf + gb->buf_size - gb->buf_put; | |
229 | if (count > len) { | |
230 | memcpy(gb->buf_put, buf, len); | |
231 | memcpy(gb->buf_buf, buf+len, count - len); | |
232 | gb->buf_put = gb->buf_buf + count - len; | |
233 | } else { | |
234 | memcpy(gb->buf_put, buf, count); | |
235 | if (count < len) | |
236 | gb->buf_put += count; | |
237 | else /* count == len */ | |
238 | gb->buf_put = gb->buf_buf; | |
239 | } | |
240 | ||
241 | return count; | |
242 | } | |
243 | ||
244 | /* | |
245 | * gs_buf_get | |
246 | * | |
247 | * Get data from the circular buffer and copy to the given buffer. | |
248 | * Restrict to the amount of data available. | |
249 | * | |
250 | * Return the number of bytes copied. | |
251 | */ | |
252 | static unsigned | |
253 | gs_buf_get(struct gs_buf *gb, char *buf, unsigned count) | |
254 | { | |
255 | unsigned len; | |
256 | ||
257 | len = gs_buf_data_avail(gb); | |
258 | if (count > len) | |
259 | count = len; | |
260 | ||
261 | if (count == 0) | |
262 | return 0; | |
263 | ||
264 | len = gb->buf_buf + gb->buf_size - gb->buf_get; | |
265 | if (count > len) { | |
266 | memcpy(buf, gb->buf_get, len); | |
267 | memcpy(buf+len, gb->buf_buf, count - len); | |
268 | gb->buf_get = gb->buf_buf + count - len; | |
269 | } else { | |
270 | memcpy(buf, gb->buf_get, count); | |
271 | if (count < len) | |
272 | gb->buf_get += count; | |
273 | else /* count == len */ | |
274 | gb->buf_get = gb->buf_buf; | |
275 | } | |
276 | ||
277 | return count; | |
278 | } | |
279 | ||
280 | /*-------------------------------------------------------------------------*/ | |
281 | ||
282 | /* I/O glue between TTY (upper) and USB function (lower) driver layers */ | |
283 | ||
284 | /* | |
285 | * gs_alloc_req | |
286 | * | |
287 | * Allocate a usb_request and its buffer. Returns a pointer to the | |
288 | * usb_request or NULL if there is an error. | |
289 | */ | |
290 | struct usb_request * | |
291 | gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) | |
292 | { | |
293 | struct usb_request *req; | |
294 | ||
295 | req = usb_ep_alloc_request(ep, kmalloc_flags); | |
296 | ||
297 | if (req != NULL) { | |
298 | req->length = len; | |
299 | req->buf = kmalloc(len, kmalloc_flags); | |
300 | if (req->buf == NULL) { | |
301 | usb_ep_free_request(ep, req); | |
302 | return NULL; | |
303 | } | |
304 | } | |
305 | ||
306 | return req; | |
307 | } | |
308 | ||
309 | /* | |
310 | * gs_free_req | |
311 | * | |
312 | * Free a usb_request and its buffer. | |
313 | */ | |
314 | void gs_free_req(struct usb_ep *ep, struct usb_request *req) | |
315 | { | |
316 | kfree(req->buf); | |
317 | usb_ep_free_request(ep, req); | |
318 | } | |
319 | ||
320 | /* | |
321 | * gs_send_packet | |
322 | * | |
323 | * If there is data to send, a packet is built in the given | |
324 | * buffer and the size is returned. If there is no data to | |
325 | * send, 0 is returned. | |
326 | * | |
327 | * Called with port_lock held. | |
328 | */ | |
329 | static unsigned | |
330 | gs_send_packet(struct gs_port *port, char *packet, unsigned size) | |
331 | { | |
332 | unsigned len; | |
333 | ||
334 | len = gs_buf_data_avail(&port->port_write_buf); | |
335 | if (len < size) | |
336 | size = len; | |
337 | if (size != 0) | |
338 | size = gs_buf_get(&port->port_write_buf, packet, size); | |
339 | return size; | |
340 | } | |
341 | ||
342 | /* | |
343 | * gs_start_tx | |
344 | * | |
345 | * This function finds available write requests, calls | |
346 | * gs_send_packet to fill these packets with data, and | |
347 | * continues until either there are no more write requests | |
348 | * available or no more data to send. This function is | |
349 | * run whenever data arrives or write requests are available. | |
350 | * | |
351 | * Context: caller owns port_lock; port_usb is non-null. | |
352 | */ | |
353 | static int gs_start_tx(struct gs_port *port) | |
354 | /* | |
355 | __releases(&port->port_lock) | |
356 | __acquires(&port->port_lock) | |
357 | */ | |
358 | { | |
359 | struct list_head *pool = &port->write_pool; | |
360 | struct usb_ep *in = port->port_usb->in; | |
361 | int status = 0; | |
362 | bool do_tty_wake = false; | |
363 | ||
364 | while (!list_empty(pool)) { | |
365 | struct usb_request *req; | |
366 | int len; | |
367 | ||
368 | if (port->write_started >= QUEUE_SIZE) | |
369 | break; | |
370 | ||
371 | req = list_entry(pool->next, struct usb_request, list); | |
372 | len = gs_send_packet(port, req->buf, in->maxpacket); | |
373 | if (len == 0) { | |
374 | wake_up_interruptible(&port->drain_wait); | |
375 | break; | |
376 | } | |
377 | do_tty_wake = true; | |
378 | ||
379 | req->length = len; | |
380 | list_del(&req->list); | |
381 | req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0); | |
382 | ||
383 | pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n", | |
384 | port->port_num, len, *((u8 *)req->buf), | |
385 | *((u8 *)req->buf+1), *((u8 *)req->buf+2)); | |
386 | ||
387 | /* Drop lock while we call out of driver; completions | |
388 | * could be issued while we do so. Disconnection may | |
389 | * happen too; maybe immediately before we queue this! | |
390 | * | |
391 | * NOTE that we may keep sending data for a while after | |
392 | * the TTY closed (dev->ioport->port_tty is NULL). | |
393 | */ | |
394 | spin_unlock(&port->port_lock); | |
395 | status = usb_ep_queue(in, req, GFP_ATOMIC); | |
396 | spin_lock(&port->port_lock); | |
397 | ||
398 | if (status) { | |
399 | pr_debug("%s: %s %s err %d\n", | |
400 | __func__, "queue", in->name, status); | |
401 | list_add(&req->list, pool); | |
402 | break; | |
403 | } | |
404 | ||
405 | port->write_started++; | |
406 | ||
407 | /* abort immediately after disconnect */ | |
408 | if (!port->port_usb) | |
409 | break; | |
410 | } | |
411 | ||
412 | if (do_tty_wake && port->port.tty) | |
413 | tty_wakeup(port->port.tty); | |
414 | return status; | |
415 | } | |
416 | ||
417 | /* | |
418 | * Context: caller owns port_lock, and port_usb is set | |
419 | */ | |
420 | static unsigned gs_start_rx(struct gs_port *port) | |
421 | /* | |
422 | __releases(&port->port_lock) | |
423 | __acquires(&port->port_lock) | |
424 | */ | |
425 | { | |
426 | struct list_head *pool = &port->read_pool; | |
427 | struct usb_ep *out = port->port_usb->out; | |
428 | ||
429 | while (!list_empty(pool)) { | |
430 | struct usb_request *req; | |
431 | int status; | |
432 | struct tty_struct *tty; | |
433 | ||
434 | /* no more rx if closed */ | |
435 | tty = port->port.tty; | |
436 | if (!tty) | |
437 | break; | |
438 | ||
439 | if (port->read_started >= QUEUE_SIZE) | |
440 | break; | |
441 | ||
442 | req = list_entry(pool->next, struct usb_request, list); | |
443 | list_del(&req->list); | |
444 | req->length = out->maxpacket; | |
445 | ||
446 | /* drop lock while we call out; the controller driver | |
447 | * may need to call us back (e.g. for disconnect) | |
448 | */ | |
449 | spin_unlock(&port->port_lock); | |
450 | status = usb_ep_queue(out, req, GFP_ATOMIC); | |
451 | spin_lock(&port->port_lock); | |
452 | ||
453 | if (status) { | |
454 | pr_debug("%s: %s %s err %d\n", | |
455 | __func__, "queue", out->name, status); | |
456 | list_add(&req->list, pool); | |
457 | break; | |
458 | } | |
459 | port->read_started++; | |
460 | ||
461 | /* abort immediately after disconnect */ | |
462 | if (!port->port_usb) | |
463 | break; | |
464 | } | |
465 | return port->read_started; | |
466 | } | |
467 | ||
468 | /* | |
469 | * RX tasklet takes data out of the RX queue and hands it up to the TTY | |
470 | * layer until it refuses to take any more data (or is throttled back). | |
471 | * Then it issues reads for any further data. | |
472 | * | |
473 | * If the RX queue becomes full enough that no usb_request is queued, | |
474 | * the OUT endpoint may begin NAKing as soon as its FIFO fills up. | |
475 | * So QUEUE_SIZE packets plus however many the FIFO holds (usually two) | |
476 | * can be buffered before the TTY layer's buffers (currently 64 KB). | |
477 | */ | |
478 | static void gs_rx_push(unsigned long _port) | |
479 | { | |
480 | struct gs_port *port = (void *)_port; | |
481 | struct tty_struct *tty; | |
482 | struct list_head *queue = &port->read_queue; | |
483 | bool disconnect = false; | |
484 | bool do_push = false; | |
485 | ||
486 | /* hand any queued data to the tty */ | |
487 | spin_lock_irq(&port->port_lock); | |
488 | tty = port->port.tty; | |
489 | while (!list_empty(queue)) { | |
490 | struct usb_request *req; | |
491 | ||
492 | req = list_first_entry(queue, struct usb_request, list); | |
493 | ||
e220ff75 | 494 | /* leave data queued if tty was rx throttled */ |
2e124b4a | 495 | if (tty && test_bit(TTY_THROTTLED, &tty->flags)) |
e220ff75 SAS |
496 | break; |
497 | ||
498 | switch (req->status) { | |
499 | case -ESHUTDOWN: | |
500 | disconnect = true; | |
501 | pr_vdebug(PREFIX "%d: shutdown\n", port->port_num); | |
502 | break; | |
503 | ||
504 | default: | |
505 | /* presumably a transient fault */ | |
506 | pr_warning(PREFIX "%d: unexpected RX status %d\n", | |
507 | port->port_num, req->status); | |
508 | /* FALLTHROUGH */ | |
509 | case 0: | |
510 | /* normal completion */ | |
511 | break; | |
512 | } | |
513 | ||
514 | /* push data to (open) tty */ | |
515 | if (req->actual) { | |
516 | char *packet = req->buf; | |
517 | unsigned size = req->actual; | |
518 | unsigned n; | |
519 | int count; | |
520 | ||
521 | /* we may have pushed part of this packet already... */ | |
522 | n = port->n_read; | |
523 | if (n) { | |
524 | packet += n; | |
525 | size -= n; | |
526 | } | |
527 | ||
05c7cd39 | 528 | count = tty_insert_flip_string(&port->port, packet, size); |
e220ff75 SAS |
529 | if (count) |
530 | do_push = true; | |
531 | if (count != size) { | |
532 | /* stop pushing; TTY layer can't handle more */ | |
533 | port->n_read += count; | |
534 | pr_vdebug(PREFIX "%d: rx block %d/%d\n", | |
535 | port->port_num, | |
536 | count, req->actual); | |
537 | break; | |
538 | } | |
539 | port->n_read = 0; | |
540 | } | |
e220ff75 SAS |
541 | list_move(&req->list, &port->read_pool); |
542 | port->read_started--; | |
543 | } | |
544 | ||
545 | /* Push from tty to ldisc; without low_latency set this is handled by | |
546 | * a workqueue, so we won't get callbacks and can hold port_lock | |
547 | */ | |
2e124b4a JS |
548 | if (do_push) |
549 | tty_flip_buffer_push(&port->port); | |
e220ff75 SAS |
550 | |
551 | ||
552 | /* We want our data queue to become empty ASAP, keeping data | |
553 | * in the tty and ldisc (not here). If we couldn't push any | |
554 | * this time around, there may be trouble unless there's an | |
555 | * implicit tty_unthrottle() call on its way... | |
556 | * | |
557 | * REVISIT we should probably add a timer to keep the tasklet | |
558 | * from starving ... but it's not clear that case ever happens. | |
559 | */ | |
560 | if (!list_empty(queue) && tty) { | |
561 | if (!test_bit(TTY_THROTTLED, &tty->flags)) { | |
562 | if (do_push) | |
563 | tasklet_schedule(&port->push); | |
564 | else | |
565 | pr_warning(PREFIX "%d: RX not scheduled?\n", | |
566 | port->port_num); | |
567 | } | |
568 | } | |
569 | ||
570 | /* If we're still connected, refill the USB RX queue. */ | |
571 | if (!disconnect && port->port_usb) | |
572 | gs_start_rx(port); | |
573 | ||
574 | spin_unlock_irq(&port->port_lock); | |
575 | } | |
576 | ||
577 | static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) | |
578 | { | |
579 | struct gs_port *port = ep->driver_data; | |
580 | ||
581 | /* Queue all received data until the tty layer is ready for it. */ | |
582 | spin_lock(&port->port_lock); | |
583 | list_add_tail(&req->list, &port->read_queue); | |
584 | tasklet_schedule(&port->push); | |
585 | spin_unlock(&port->port_lock); | |
586 | } | |
587 | ||
588 | static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) | |
589 | { | |
590 | struct gs_port *port = ep->driver_data; | |
591 | ||
592 | spin_lock(&port->port_lock); | |
593 | list_add(&req->list, &port->write_pool); | |
594 | port->write_started--; | |
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 | int *allocated) | |
618 | { | |
619 | struct usb_request *req; | |
620 | ||
621 | while (!list_empty(head)) { | |
622 | req = list_entry(head->next, struct usb_request, list); | |
623 | list_del(&req->list); | |
624 | gs_free_req(ep, req); | |
625 | if (allocated) | |
626 | (*allocated)--; | |
627 | } | |
628 | } | |
629 | ||
630 | static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, | |
631 | void (*fn)(struct usb_ep *, struct usb_request *), | |
632 | int *allocated) | |
633 | { | |
634 | int i; | |
635 | struct usb_request *req; | |
636 | int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE; | |
637 | ||
638 | /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't | |
639 | * do quite that many this time, don't fail ... we just won't | |
640 | * be as speedy as we might otherwise be. | |
641 | */ | |
642 | for (i = 0; i < n; i++) { | |
643 | req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); | |
644 | if (!req) | |
645 | return list_empty(head) ? -ENOMEM : 0; | |
646 | req->complete = fn; | |
647 | list_add_tail(&req->list, head); | |
648 | if (allocated) | |
649 | (*allocated)++; | |
650 | } | |
651 | return 0; | |
652 | } | |
653 | ||
654 | /** | |
655 | * gs_start_io - start USB I/O streams | |
656 | * @dev: encapsulates endpoints to use | |
657 | * Context: holding port_lock; port_tty and port_usb are non-null | |
658 | * | |
659 | * We only start I/O when something is connected to both sides of | |
660 | * this port. If nothing is listening on the host side, we may | |
661 | * be pointlessly filling up our TX buffers and FIFO. | |
662 | */ | |
663 | static int gs_start_io(struct gs_port *port) | |
664 | { | |
665 | struct list_head *head = &port->read_pool; | |
666 | struct usb_ep *ep = port->port_usb->out; | |
667 | int status; | |
668 | unsigned started; | |
669 | ||
670 | /* Allocate RX and TX I/O buffers. We can't easily do this much | |
671 | * earlier (with GFP_KERNEL) because the requests are coupled to | |
672 | * endpoints, as are the packet sizes we'll be using. Different | |
673 | * configurations may use different endpoints with a given port; | |
674 | * and high speed vs full speed changes packet sizes too. | |
675 | */ | |
676 | status = gs_alloc_requests(ep, head, gs_read_complete, | |
677 | &port->read_allocated); | |
678 | if (status) | |
679 | return status; | |
680 | ||
681 | status = gs_alloc_requests(port->port_usb->in, &port->write_pool, | |
682 | gs_write_complete, &port->write_allocated); | |
683 | if (status) { | |
684 | gs_free_requests(ep, head, &port->read_allocated); | |
685 | return status; | |
686 | } | |
687 | ||
688 | /* queue read requests */ | |
689 | port->n_read = 0; | |
690 | started = gs_start_rx(port); | |
691 | ||
692 | /* unblock any pending writes into our circular buffer */ | |
693 | if (started) { | |
694 | tty_wakeup(port->port.tty); | |
695 | } else { | |
696 | gs_free_requests(ep, head, &port->read_allocated); | |
697 | gs_free_requests(port->port_usb->in, &port->write_pool, | |
698 | &port->write_allocated); | |
699 | status = -EIO; | |
700 | } | |
701 | ||
702 | return status; | |
703 | } | |
704 | ||
705 | /*-------------------------------------------------------------------------*/ | |
706 | ||
707 | /* TTY Driver */ | |
708 | ||
709 | /* | |
710 | * gs_open sets up the link between a gs_port and its associated TTY. | |
711 | * That link is broken *only* by TTY close(), and all driver methods | |
712 | * know that. | |
713 | */ | |
714 | static int gs_open(struct tty_struct *tty, struct file *file) | |
715 | { | |
716 | int port_num = tty->index; | |
717 | struct gs_port *port; | |
718 | int status; | |
719 | ||
720 | do { | |
721 | mutex_lock(&ports[port_num].lock); | |
722 | port = ports[port_num].port; | |
723 | if (!port) | |
724 | status = -ENODEV; | |
725 | else { | |
726 | spin_lock_irq(&port->port_lock); | |
727 | ||
728 | /* already open? Great. */ | |
729 | if (port->port.count) { | |
730 | status = 0; | |
731 | port->port.count++; | |
732 | ||
733 | /* currently opening/closing? wait ... */ | |
734 | } else if (port->openclose) { | |
735 | status = -EBUSY; | |
736 | ||
737 | /* ... else we do the work */ | |
738 | } else { | |
739 | status = -EAGAIN; | |
740 | port->openclose = true; | |
741 | } | |
742 | spin_unlock_irq(&port->port_lock); | |
743 | } | |
744 | mutex_unlock(&ports[port_num].lock); | |
745 | ||
746 | switch (status) { | |
747 | default: | |
748 | /* fully handled */ | |
749 | return status; | |
750 | case -EAGAIN: | |
751 | /* must do the work */ | |
752 | break; | |
753 | case -EBUSY: | |
754 | /* wait for EAGAIN task to finish */ | |
755 | msleep(1); | |
756 | /* REVISIT could have a waitchannel here, if | |
757 | * concurrent open performance is important | |
758 | */ | |
759 | break; | |
760 | } | |
761 | } while (status != -EAGAIN); | |
762 | ||
763 | /* Do the "real open" */ | |
764 | spin_lock_irq(&port->port_lock); | |
765 | ||
766 | /* allocate circular buffer on first open */ | |
767 | if (port->port_write_buf.buf_buf == NULL) { | |
768 | ||
769 | spin_unlock_irq(&port->port_lock); | |
770 | status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE); | |
771 | spin_lock_irq(&port->port_lock); | |
772 | ||
773 | if (status) { | |
774 | pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n", | |
775 | port->port_num, tty, file); | |
776 | port->openclose = false; | |
777 | goto exit_unlock_port; | |
778 | } | |
779 | } | |
780 | ||
781 | /* REVISIT if REMOVED (ports[].port NULL), abort the open | |
782 | * to let rmmod work faster (but this way isn't wrong). | |
783 | */ | |
784 | ||
785 | /* REVISIT maybe wait for "carrier detect" */ | |
786 | ||
787 | tty->driver_data = port; | |
788 | port->port.tty = tty; | |
789 | ||
790 | port->port.count = 1; | |
791 | port->openclose = false; | |
792 | ||
793 | /* if connected, start the I/O stream */ | |
794 | if (port->port_usb) { | |
795 | struct gserial *gser = port->port_usb; | |
796 | ||
797 | pr_debug("gs_open: start ttyGS%d\n", port->port_num); | |
798 | gs_start_io(port); | |
799 | ||
800 | if (gser->connect) | |
801 | gser->connect(gser); | |
802 | } | |
803 | ||
804 | pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); | |
805 | ||
806 | status = 0; | |
807 | ||
808 | exit_unlock_port: | |
809 | spin_unlock_irq(&port->port_lock); | |
810 | return status; | |
811 | } | |
812 | ||
813 | static int gs_writes_finished(struct gs_port *p) | |
814 | { | |
815 | int cond; | |
816 | ||
817 | /* return true on disconnect or empty buffer */ | |
818 | spin_lock_irq(&p->port_lock); | |
819 | cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf); | |
820 | spin_unlock_irq(&p->port_lock); | |
821 | ||
822 | return cond; | |
823 | } | |
824 | ||
825 | static void gs_close(struct tty_struct *tty, struct file *file) | |
826 | { | |
827 | struct gs_port *port = tty->driver_data; | |
828 | struct gserial *gser; | |
829 | ||
830 | spin_lock_irq(&port->port_lock); | |
831 | ||
832 | if (port->port.count != 1) { | |
833 | if (port->port.count == 0) | |
834 | WARN_ON(1); | |
835 | else | |
836 | --port->port.count; | |
837 | goto exit; | |
838 | } | |
839 | ||
840 | pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); | |
841 | ||
842 | /* mark port as closing but in use; we can drop port lock | |
843 | * and sleep if necessary | |
844 | */ | |
845 | port->openclose = true; | |
846 | port->port.count = 0; | |
847 | ||
848 | gser = port->port_usb; | |
849 | if (gser && gser->disconnect) | |
850 | gser->disconnect(gser); | |
851 | ||
852 | /* wait for circular write buffer to drain, disconnect, or at | |
853 | * most GS_CLOSE_TIMEOUT seconds; then discard the rest | |
854 | */ | |
855 | if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) { | |
856 | spin_unlock_irq(&port->port_lock); | |
857 | wait_event_interruptible_timeout(port->drain_wait, | |
858 | gs_writes_finished(port), | |
859 | GS_CLOSE_TIMEOUT * HZ); | |
860 | spin_lock_irq(&port->port_lock); | |
861 | gser = port->port_usb; | |
862 | } | |
863 | ||
864 | /* Iff we're disconnected, there can be no I/O in flight so it's | |
865 | * ok to free the circular buffer; else just scrub it. And don't | |
866 | * let the push tasklet fire again until we're re-opened. | |
867 | */ | |
868 | if (gser == NULL) | |
869 | gs_buf_free(&port->port_write_buf); | |
870 | else | |
871 | gs_buf_clear(&port->port_write_buf); | |
872 | ||
873 | tty->driver_data = NULL; | |
874 | port->port.tty = NULL; | |
875 | ||
876 | port->openclose = false; | |
877 | ||
878 | pr_debug("gs_close: ttyGS%d (%p,%p) done!\n", | |
879 | port->port_num, tty, file); | |
880 | ||
881 | wake_up_interruptible(&port->port.close_wait); | |
882 | exit: | |
883 | spin_unlock_irq(&port->port_lock); | |
884 | } | |
885 | ||
886 | static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
887 | { | |
888 | struct gs_port *port = tty->driver_data; | |
889 | unsigned long flags; | |
890 | int status; | |
891 | ||
892 | pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n", | |
893 | port->port_num, tty, count); | |
894 | ||
895 | spin_lock_irqsave(&port->port_lock, flags); | |
896 | if (count) | |
897 | count = gs_buf_put(&port->port_write_buf, buf, count); | |
898 | /* treat count == 0 as flush_chars() */ | |
899 | if (port->port_usb) | |
900 | status = gs_start_tx(port); | |
901 | spin_unlock_irqrestore(&port->port_lock, flags); | |
902 | ||
903 | return count; | |
904 | } | |
905 | ||
906 | static int gs_put_char(struct tty_struct *tty, unsigned char ch) | |
907 | { | |
908 | struct gs_port *port = tty->driver_data; | |
909 | unsigned long flags; | |
910 | int status; | |
911 | ||
912 | pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %pf\n", | |
913 | port->port_num, tty, ch, __builtin_return_address(0)); | |
914 | ||
915 | spin_lock_irqsave(&port->port_lock, flags); | |
916 | status = gs_buf_put(&port->port_write_buf, &ch, 1); | |
917 | spin_unlock_irqrestore(&port->port_lock, flags); | |
918 | ||
919 | return status; | |
920 | } | |
921 | ||
922 | static void gs_flush_chars(struct tty_struct *tty) | |
923 | { | |
924 | struct gs_port *port = tty->driver_data; | |
925 | unsigned long flags; | |
926 | ||
927 | pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty); | |
928 | ||
929 | spin_lock_irqsave(&port->port_lock, flags); | |
930 | if (port->port_usb) | |
931 | gs_start_tx(port); | |
932 | spin_unlock_irqrestore(&port->port_lock, flags); | |
933 | } | |
934 | ||
935 | static int gs_write_room(struct tty_struct *tty) | |
936 | { | |
937 | struct gs_port *port = tty->driver_data; | |
938 | unsigned long flags; | |
939 | int room = 0; | |
940 | ||
941 | spin_lock_irqsave(&port->port_lock, flags); | |
942 | if (port->port_usb) | |
943 | room = gs_buf_space_avail(&port->port_write_buf); | |
944 | spin_unlock_irqrestore(&port->port_lock, flags); | |
945 | ||
946 | pr_vdebug("gs_write_room: (%d,%p) room=%d\n", | |
947 | port->port_num, tty, room); | |
948 | ||
949 | return room; | |
950 | } | |
951 | ||
952 | static int gs_chars_in_buffer(struct tty_struct *tty) | |
953 | { | |
954 | struct gs_port *port = tty->driver_data; | |
955 | unsigned long flags; | |
956 | int chars = 0; | |
957 | ||
958 | spin_lock_irqsave(&port->port_lock, flags); | |
959 | chars = gs_buf_data_avail(&port->port_write_buf); | |
960 | spin_unlock_irqrestore(&port->port_lock, flags); | |
961 | ||
962 | pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n", | |
963 | port->port_num, tty, chars); | |
964 | ||
965 | return chars; | |
966 | } | |
967 | ||
968 | /* undo side effects of setting TTY_THROTTLED */ | |
969 | static void gs_unthrottle(struct tty_struct *tty) | |
970 | { | |
971 | struct gs_port *port = tty->driver_data; | |
972 | unsigned long flags; | |
973 | ||
974 | spin_lock_irqsave(&port->port_lock, flags); | |
975 | if (port->port_usb) { | |
976 | /* Kickstart read queue processing. We don't do xon/xoff, | |
977 | * rts/cts, or other handshaking with the host, but if the | |
978 | * read queue backs up enough we'll be NAKing OUT packets. | |
979 | */ | |
980 | tasklet_schedule(&port->push); | |
981 | pr_vdebug(PREFIX "%d: unthrottle\n", port->port_num); | |
982 | } | |
983 | spin_unlock_irqrestore(&port->port_lock, flags); | |
984 | } | |
985 | ||
986 | static int gs_break_ctl(struct tty_struct *tty, int duration) | |
987 | { | |
988 | struct gs_port *port = tty->driver_data; | |
989 | int status = 0; | |
990 | struct gserial *gser; | |
991 | ||
992 | pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n", | |
993 | port->port_num, duration); | |
994 | ||
995 | spin_lock_irq(&port->port_lock); | |
996 | gser = port->port_usb; | |
997 | if (gser && gser->send_break) | |
998 | status = gser->send_break(gser, duration); | |
999 | spin_unlock_irq(&port->port_lock); | |
1000 | ||
1001 | return status; | |
1002 | } | |
1003 | ||
1004 | static const struct tty_operations gs_tty_ops = { | |
1005 | .open = gs_open, | |
1006 | .close = gs_close, | |
1007 | .write = gs_write, | |
1008 | .put_char = gs_put_char, | |
1009 | .flush_chars = gs_flush_chars, | |
1010 | .write_room = gs_write_room, | |
1011 | .chars_in_buffer = gs_chars_in_buffer, | |
1012 | .unthrottle = gs_unthrottle, | |
1013 | .break_ctl = gs_break_ctl, | |
1014 | }; | |
1015 | ||
1016 | /*-------------------------------------------------------------------------*/ | |
1017 | ||
1018 | static struct tty_driver *gs_tty_driver; | |
1019 | ||
1020 | static int | |
1021 | gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) | |
1022 | { | |
1023 | struct gs_port *port; | |
1024 | ||
1025 | port = kzalloc(sizeof(struct gs_port), GFP_KERNEL); | |
1026 | if (port == NULL) | |
1027 | return -ENOMEM; | |
1028 | ||
1029 | tty_port_init(&port->port); | |
1030 | spin_lock_init(&port->port_lock); | |
1031 | init_waitqueue_head(&port->drain_wait); | |
1032 | ||
1033 | tasklet_init(&port->push, gs_rx_push, (unsigned long) port); | |
1034 | ||
1035 | INIT_LIST_HEAD(&port->read_pool); | |
1036 | INIT_LIST_HEAD(&port->read_queue); | |
1037 | INIT_LIST_HEAD(&port->write_pool); | |
1038 | ||
1039 | port->port_num = port_num; | |
1040 | port->port_line_coding = *coding; | |
1041 | ||
1042 | ports[port_num].port = port; | |
1043 | ||
1044 | return 0; | |
1045 | } | |
1046 | ||
1047 | /** | |
1048 | * gserial_setup - initialize TTY driver for one or more ports | |
1049 | * @g: gadget to associate with these ports | |
1050 | * @count: how many ports to support | |
1051 | * Context: may sleep | |
1052 | * | |
1053 | * The TTY stack needs to know in advance how many devices it should | |
1054 | * plan to manage. Use this call to set up the ports you will be | |
1055 | * exporting through USB. Later, connect them to functions based | |
1056 | * on what configuration is activated by the USB host; and disconnect | |
1057 | * them as appropriate. | |
1058 | * | |
1059 | * An example would be a two-configuration device in which both | |
1060 | * configurations expose port 0, but through different functions. | |
1061 | * One configuration could even expose port 1 while the other | |
1062 | * one doesn't. | |
1063 | * | |
1064 | * Returns negative errno or zero. | |
1065 | */ | |
1066 | int gserial_setup(struct usb_gadget *g, unsigned count) | |
1067 | { | |
1068 | unsigned i; | |
1069 | struct usb_cdc_line_coding coding; | |
1070 | int status; | |
1071 | ||
1072 | if (count == 0 || count > N_PORTS) | |
1073 | return -EINVAL; | |
1074 | ||
1075 | gs_tty_driver = alloc_tty_driver(count); | |
1076 | if (!gs_tty_driver) | |
1077 | return -ENOMEM; | |
1078 | ||
1079 | gs_tty_driver->driver_name = "g_serial"; | |
1080 | gs_tty_driver->name = PREFIX; | |
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 | ||
1097 | coding.dwDTERate = cpu_to_le32(9600); | |
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) { | |
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: | |
191c5f10 JS |
1138 | while (count--) { |
1139 | tty_port_destroy(&ports[count].port->port); | |
e220ff75 | 1140 | kfree(ports[count].port); |
191c5f10 | 1141 | } |
e220ff75 SAS |
1142 | put_tty_driver(gs_tty_driver); |
1143 | gs_tty_driver = NULL; | |
1144 | return status; | |
1145 | } | |
1146 | ||
1147 | static int gs_closed(struct gs_port *port) | |
1148 | { | |
1149 | int cond; | |
1150 | ||
1151 | spin_lock_irq(&port->port_lock); | |
1152 | cond = (port->port.count == 0) && !port->openclose; | |
1153 | spin_unlock_irq(&port->port_lock); | |
1154 | return cond; | |
1155 | } | |
1156 | ||
1157 | /** | |
1158 | * gserial_cleanup - remove TTY-over-USB driver and devices | |
1159 | * Context: may sleep | |
1160 | * | |
1161 | * This is called to free all resources allocated by @gserial_setup(). | |
1162 | * Accordingly, it may need to wait until some open /dev/ files have | |
1163 | * closed. | |
1164 | * | |
1165 | * The caller must have issued @gserial_disconnect() for any ports | |
1166 | * that had previously been connected, so that there is never any | |
1167 | * I/O pending when it's called. | |
1168 | */ | |
1169 | void gserial_cleanup(void) | |
1170 | { | |
1171 | unsigned i; | |
1172 | struct gs_port *port; | |
1173 | ||
1174 | if (!gs_tty_driver) | |
1175 | return; | |
1176 | ||
1177 | /* start sysfs and /dev/ttyGS* node removal */ | |
1178 | for (i = 0; i < n_ports; i++) | |
1179 | tty_unregister_device(gs_tty_driver, i); | |
1180 | ||
1181 | for (i = 0; i < n_ports; i++) { | |
1182 | /* prevent new opens */ | |
1183 | mutex_lock(&ports[i].lock); | |
1184 | port = ports[i].port; | |
1185 | ports[i].port = NULL; | |
1186 | mutex_unlock(&ports[i].lock); | |
1187 | ||
1188 | tasklet_kill(&port->push); | |
1189 | ||
1190 | /* wait for old opens to finish */ | |
1191 | wait_event(port->port.close_wait, gs_closed(port)); | |
1192 | ||
1193 | WARN_ON(port->port_usb != NULL); | |
1194 | ||
191c5f10 | 1195 | tty_port_destroy(&port->port); |
e220ff75 SAS |
1196 | kfree(port); |
1197 | } | |
1198 | n_ports = 0; | |
1199 | ||
1200 | tty_unregister_driver(gs_tty_driver); | |
1201 | put_tty_driver(gs_tty_driver); | |
1202 | gs_tty_driver = NULL; | |
1203 | ||
1204 | pr_debug("%s: cleaned up ttyGS* support\n", __func__); | |
1205 | } | |
1206 | ||
1207 | /** | |
1208 | * gserial_connect - notify TTY I/O glue that USB link is active | |
1209 | * @gser: the function, set up with endpoints and descriptors | |
1210 | * @port_num: which port is active | |
1211 | * Context: any (usually from irq) | |
1212 | * | |
1213 | * This is called activate endpoints and let the TTY layer know that | |
1214 | * the connection is active ... not unlike "carrier detect". It won't | |
1215 | * necessarily start I/O queues; unless the TTY is held open by any | |
1216 | * task, there would be no point. However, the endpoints will be | |
1217 | * activated so the USB host can perform I/O, subject to basic USB | |
1218 | * hardware flow control. | |
1219 | * | |
1220 | * Caller needs to have set up the endpoints and USB function in @dev | |
1221 | * before calling this, as well as the appropriate (speed-specific) | |
1222 | * endpoint descriptors, and also have set up the TTY driver by calling | |
1223 | * @gserial_setup(). | |
1224 | * | |
1225 | * Returns negative errno or zero. | |
1226 | * On success, ep->driver_data will be overwritten. | |
1227 | */ | |
1228 | int gserial_connect(struct gserial *gser, u8 port_num) | |
1229 | { | |
1230 | struct gs_port *port; | |
1231 | unsigned long flags; | |
1232 | int status; | |
1233 | ||
1234 | if (!gs_tty_driver || port_num >= n_ports) | |
1235 | return -ENXIO; | |
1236 | ||
1237 | /* we "know" gserial_cleanup() hasn't been called */ | |
1238 | port = ports[port_num].port; | |
1239 | ||
1240 | /* activate the endpoints */ | |
1241 | status = usb_ep_enable(gser->in); | |
1242 | if (status < 0) | |
1243 | return status; | |
1244 | gser->in->driver_data = port; | |
1245 | ||
1246 | status = usb_ep_enable(gser->out); | |
1247 | if (status < 0) | |
1248 | goto fail_out; | |
1249 | gser->out->driver_data = port; | |
1250 | ||
1251 | /* then tell the tty glue that I/O can work */ | |
1252 | spin_lock_irqsave(&port->port_lock, flags); | |
1253 | gser->ioport = port; | |
1254 | port->port_usb = gser; | |
1255 | ||
1256 | /* REVISIT unclear how best to handle this state... | |
1257 | * we don't really couple it with the Linux TTY. | |
1258 | */ | |
1259 | gser->port_line_coding = port->port_line_coding; | |
1260 | ||
1261 | /* REVISIT if waiting on "carrier detect", signal. */ | |
1262 | ||
1263 | /* if it's already open, start I/O ... and notify the serial | |
1264 | * protocol about open/close status (connect/disconnect). | |
1265 | */ | |
1266 | if (port->port.count) { | |
1267 | pr_debug("gserial_connect: start ttyGS%d\n", port->port_num); | |
1268 | gs_start_io(port); | |
1269 | if (gser->connect) | |
1270 | gser->connect(gser); | |
1271 | } else { | |
1272 | if (gser->disconnect) | |
1273 | gser->disconnect(gser); | |
1274 | } | |
1275 | ||
1276 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1277 | ||
1278 | return status; | |
1279 | ||
1280 | fail_out: | |
1281 | usb_ep_disable(gser->in); | |
1282 | gser->in->driver_data = NULL; | |
1283 | return status; | |
1284 | } | |
1285 | ||
1286 | /** | |
1287 | * gserial_disconnect - notify TTY I/O glue that USB link is inactive | |
1288 | * @gser: the function, on which gserial_connect() was called | |
1289 | * Context: any (usually from irq) | |
1290 | * | |
1291 | * This is called to deactivate endpoints and let the TTY layer know | |
1292 | * that the connection went inactive ... not unlike "hangup". | |
1293 | * | |
1294 | * On return, the state is as if gserial_connect() had never been called; | |
1295 | * there is no active USB I/O on these endpoints. | |
1296 | */ | |
1297 | void gserial_disconnect(struct gserial *gser) | |
1298 | { | |
1299 | struct gs_port *port = gser->ioport; | |
1300 | unsigned long flags; | |
1301 | ||
1302 | if (!port) | |
1303 | return; | |
1304 | ||
1305 | /* tell the TTY glue not to do I/O here any more */ | |
1306 | spin_lock_irqsave(&port->port_lock, flags); | |
1307 | ||
1308 | /* REVISIT as above: how best to track this? */ | |
1309 | port->port_line_coding = gser->port_line_coding; | |
1310 | ||
1311 | port->port_usb = NULL; | |
1312 | gser->ioport = NULL; | |
1313 | if (port->port.count > 0 || port->openclose) { | |
1314 | wake_up_interruptible(&port->drain_wait); | |
1315 | if (port->port.tty) | |
1316 | tty_hangup(port->port.tty); | |
1317 | } | |
1318 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1319 | ||
1320 | /* disable endpoints, aborting down any active I/O */ | |
1321 | usb_ep_disable(gser->out); | |
1322 | gser->out->driver_data = NULL; | |
1323 | ||
1324 | usb_ep_disable(gser->in); | |
1325 | gser->in->driver_data = NULL; | |
1326 | ||
1327 | /* finally, free any unused/unusable I/O buffers */ | |
1328 | spin_lock_irqsave(&port->port_lock, flags); | |
1329 | if (port->port.count == 0 && !port->openclose) | |
1330 | gs_buf_free(&port->port_write_buf); | |
1331 | gs_free_requests(gser->out, &port->read_pool, NULL); | |
1332 | gs_free_requests(gser->out, &port->read_queue, NULL); | |
1333 | gs_free_requests(gser->in, &port->write_pool, NULL); | |
1334 | ||
1335 | port->read_allocated = port->read_started = | |
1336 | port->write_allocated = port->write_started = 0; | |
1337 | ||
1338 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1339 | } |