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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> | |
1e413943 | 21 | #include <linux/sched.h> |
c1dca562 DB |
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> | |
5a0e3ad6 | 27 | #include <linux/slab.h> |
f940fcd8 | 28 | #include <linux/export.h> |
c1dca562 DB |
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 | ||
937ef73d DB |
58 | #define PREFIX "ttyGS" |
59 | ||
c1dca562 DB |
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 | |
1f1ba11b DB |
66 | * inactive; managed by gserial_{connect,disconnect}(). each gserial |
67 | * instance can wrap its own USB control protocol. | |
c1dca562 DB |
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 { | |
266e37ef | 97 | struct tty_port port; |
c1dca562 DB |
98 | spinlock_t port_lock; /* guard port_* access */ |
99 | ||
100 | struct gserial *port_usb; | |
c1dca562 | 101 | |
c1dca562 DB |
102 | bool openclose; /* open/close in progress */ |
103 | u8 port_num; | |
104 | ||
c1dca562 | 105 | struct list_head read_pool; |
28609d40 JS |
106 | int read_started; |
107 | int read_allocated; | |
937ef73d DB |
108 | struct list_head read_queue; |
109 | unsigned n_read; | |
c1dca562 DB |
110 | struct tasklet_struct push; |
111 | ||
112 | struct list_head write_pool; | |
28609d40 JS |
113 | int write_started; |
114 | int write_allocated; | |
c1dca562 DB |
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 | |
ea0e6276 | 135 | #ifndef pr_vdebug |
c1dca562 DB |
136 | #define pr_vdebug(fmt, arg...) \ |
137 | pr_debug(fmt, ##arg) | |
ea0e6276 | 138 | #endif /* pr_vdebug */ |
c1dca562 | 139 | #else |
ea0e6276 | 140 | #ifndef pr_vdebig |
c1dca562 DB |
141 | #define pr_vdebug(fmt, arg...) \ |
142 | ({ if (0) pr_debug(fmt, ##arg); }) | |
ea0e6276 | 143 | #endif /* pr_vdebug */ |
c1dca562 DB |
144 | #endif |
145 | ||
146 | /*-------------------------------------------------------------------------*/ | |
147 | ||
148 | /* Circular Buffer */ | |
149 | ||
150 | /* | |
151 | * gs_buf_alloc | |
152 | * | |
153 | * Allocate a circular buffer and all associated memory. | |
154 | */ | |
155 | static int gs_buf_alloc(struct gs_buf *gb, unsigned size) | |
156 | { | |
157 | gb->buf_buf = kmalloc(size, GFP_KERNEL); | |
158 | if (gb->buf_buf == NULL) | |
159 | return -ENOMEM; | |
160 | ||
161 | gb->buf_size = size; | |
162 | gb->buf_put = gb->buf_buf; | |
163 | gb->buf_get = gb->buf_buf; | |
164 | ||
165 | return 0; | |
166 | } | |
167 | ||
168 | /* | |
169 | * gs_buf_free | |
170 | * | |
171 | * Free the buffer and all associated memory. | |
172 | */ | |
173 | static void gs_buf_free(struct gs_buf *gb) | |
174 | { | |
175 | kfree(gb->buf_buf); | |
176 | gb->buf_buf = NULL; | |
177 | } | |
178 | ||
179 | /* | |
180 | * gs_buf_clear | |
181 | * | |
182 | * Clear out all data in the circular buffer. | |
183 | */ | |
184 | static void gs_buf_clear(struct gs_buf *gb) | |
185 | { | |
186 | gb->buf_get = gb->buf_put; | |
187 | /* equivalent to a get of all data available */ | |
188 | } | |
189 | ||
190 | /* | |
191 | * gs_buf_data_avail | |
192 | * | |
1f1ba11b | 193 | * Return the number of bytes of data written into the circular |
c1dca562 DB |
194 | * buffer. |
195 | */ | |
196 | static unsigned gs_buf_data_avail(struct gs_buf *gb) | |
197 | { | |
198 | return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size; | |
199 | } | |
200 | ||
201 | /* | |
202 | * gs_buf_space_avail | |
203 | * | |
204 | * Return the number of bytes of space available in the circular | |
205 | * buffer. | |
206 | */ | |
207 | static unsigned gs_buf_space_avail(struct gs_buf *gb) | |
208 | { | |
209 | return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size; | |
210 | } | |
211 | ||
212 | /* | |
213 | * gs_buf_put | |
214 | * | |
215 | * Copy data data from a user buffer and put it into the circular buffer. | |
216 | * Restrict to the amount of space available. | |
217 | * | |
218 | * Return the number of bytes copied. | |
219 | */ | |
220 | static unsigned | |
221 | gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count) | |
222 | { | |
223 | unsigned len; | |
224 | ||
225 | len = gs_buf_space_avail(gb); | |
226 | if (count > len) | |
227 | count = len; | |
228 | ||
229 | if (count == 0) | |
230 | return 0; | |
231 | ||
232 | len = gb->buf_buf + gb->buf_size - gb->buf_put; | |
233 | if (count > len) { | |
234 | memcpy(gb->buf_put, buf, len); | |
235 | memcpy(gb->buf_buf, buf+len, count - len); | |
236 | gb->buf_put = gb->buf_buf + count - len; | |
237 | } else { | |
238 | memcpy(gb->buf_put, buf, count); | |
239 | if (count < len) | |
240 | gb->buf_put += count; | |
241 | else /* count == len */ | |
242 | gb->buf_put = gb->buf_buf; | |
243 | } | |
244 | ||
245 | return count; | |
246 | } | |
247 | ||
248 | /* | |
249 | * gs_buf_get | |
250 | * | |
251 | * Get data from the circular buffer and copy to the given buffer. | |
252 | * Restrict to the amount of data available. | |
253 | * | |
254 | * Return the number of bytes copied. | |
255 | */ | |
256 | static unsigned | |
257 | gs_buf_get(struct gs_buf *gb, char *buf, unsigned count) | |
258 | { | |
259 | unsigned len; | |
260 | ||
261 | len = gs_buf_data_avail(gb); | |
262 | if (count > len) | |
263 | count = len; | |
264 | ||
265 | if (count == 0) | |
266 | return 0; | |
267 | ||
268 | len = gb->buf_buf + gb->buf_size - gb->buf_get; | |
269 | if (count > len) { | |
270 | memcpy(buf, gb->buf_get, len); | |
271 | memcpy(buf+len, gb->buf_buf, count - len); | |
272 | gb->buf_get = gb->buf_buf + count - len; | |
273 | } else { | |
274 | memcpy(buf, gb->buf_get, count); | |
275 | if (count < len) | |
276 | gb->buf_get += count; | |
277 | else /* count == len */ | |
278 | gb->buf_get = gb->buf_buf; | |
279 | } | |
280 | ||
281 | return count; | |
282 | } | |
283 | ||
284 | /*-------------------------------------------------------------------------*/ | |
285 | ||
286 | /* I/O glue between TTY (upper) and USB function (lower) driver layers */ | |
287 | ||
288 | /* | |
289 | * gs_alloc_req | |
290 | * | |
291 | * Allocate a usb_request and its buffer. Returns a pointer to the | |
292 | * usb_request or NULL if there is an error. | |
293 | */ | |
1f1ba11b | 294 | struct usb_request * |
c1dca562 DB |
295 | gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) |
296 | { | |
297 | struct usb_request *req; | |
298 | ||
299 | req = usb_ep_alloc_request(ep, kmalloc_flags); | |
300 | ||
301 | if (req != NULL) { | |
302 | req->length = len; | |
303 | req->buf = kmalloc(len, kmalloc_flags); | |
304 | if (req->buf == NULL) { | |
305 | usb_ep_free_request(ep, req); | |
306 | return NULL; | |
307 | } | |
308 | } | |
309 | ||
310 | return req; | |
311 | } | |
312 | ||
313 | /* | |
314 | * gs_free_req | |
315 | * | |
316 | * Free a usb_request and its buffer. | |
317 | */ | |
1f1ba11b | 318 | void gs_free_req(struct usb_ep *ep, struct usb_request *req) |
c1dca562 DB |
319 | { |
320 | kfree(req->buf); | |
321 | usb_ep_free_request(ep, req); | |
322 | } | |
323 | ||
324 | /* | |
325 | * gs_send_packet | |
326 | * | |
327 | * If there is data to send, a packet is built in the given | |
328 | * buffer and the size is returned. If there is no data to | |
329 | * send, 0 is returned. | |
330 | * | |
331 | * Called with port_lock held. | |
332 | */ | |
333 | static unsigned | |
334 | gs_send_packet(struct gs_port *port, char *packet, unsigned size) | |
335 | { | |
336 | unsigned len; | |
337 | ||
338 | len = gs_buf_data_avail(&port->port_write_buf); | |
339 | if (len < size) | |
340 | size = len; | |
341 | if (size != 0) | |
342 | size = gs_buf_get(&port->port_write_buf, packet, size); | |
343 | return size; | |
344 | } | |
345 | ||
346 | /* | |
347 | * gs_start_tx | |
348 | * | |
349 | * This function finds available write requests, calls | |
350 | * gs_send_packet to fill these packets with data, and | |
351 | * continues until either there are no more write requests | |
352 | * available or no more data to send. This function is | |
353 | * run whenever data arrives or write requests are available. | |
354 | * | |
355 | * Context: caller owns port_lock; port_usb is non-null. | |
356 | */ | |
357 | static int gs_start_tx(struct gs_port *port) | |
358 | /* | |
359 | __releases(&port->port_lock) | |
360 | __acquires(&port->port_lock) | |
361 | */ | |
362 | { | |
363 | struct list_head *pool = &port->write_pool; | |
364 | struct usb_ep *in = port->port_usb->in; | |
365 | int status = 0; | |
366 | bool do_tty_wake = false; | |
367 | ||
368 | while (!list_empty(pool)) { | |
369 | struct usb_request *req; | |
370 | int len; | |
371 | ||
28609d40 JS |
372 | if (port->write_started >= QUEUE_SIZE) |
373 | break; | |
374 | ||
c1dca562 DB |
375 | req = list_entry(pool->next, struct usb_request, list); |
376 | len = gs_send_packet(port, req->buf, in->maxpacket); | |
377 | if (len == 0) { | |
378 | wake_up_interruptible(&port->drain_wait); | |
379 | break; | |
380 | } | |
381 | do_tty_wake = true; | |
382 | ||
383 | req->length = len; | |
384 | list_del(&req->list); | |
2e251341 | 385 | req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0); |
c1dca562 | 386 | |
937ef73d DB |
387 | pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n", |
388 | port->port_num, len, *((u8 *)req->buf), | |
c1dca562 | 389 | *((u8 *)req->buf+1), *((u8 *)req->buf+2)); |
c1dca562 DB |
390 | |
391 | /* Drop lock while we call out of driver; completions | |
392 | * could be issued while we do so. Disconnection may | |
393 | * happen too; maybe immediately before we queue this! | |
394 | * | |
395 | * NOTE that we may keep sending data for a while after | |
396 | * the TTY closed (dev->ioport->port_tty is NULL). | |
397 | */ | |
398 | spin_unlock(&port->port_lock); | |
399 | status = usb_ep_queue(in, req, GFP_ATOMIC); | |
400 | spin_lock(&port->port_lock); | |
401 | ||
402 | if (status) { | |
403 | pr_debug("%s: %s %s err %d\n", | |
404 | __func__, "queue", in->name, status); | |
405 | list_add(&req->list, pool); | |
406 | break; | |
407 | } | |
408 | ||
28609d40 JS |
409 | port->write_started++; |
410 | ||
c1dca562 DB |
411 | /* abort immediately after disconnect */ |
412 | if (!port->port_usb) | |
413 | break; | |
414 | } | |
415 | ||
35f95fd7 JS |
416 | if (do_tty_wake && port->port.tty) |
417 | tty_wakeup(port->port.tty); | |
c1dca562 DB |
418 | return status; |
419 | } | |
420 | ||
c1dca562 DB |
421 | /* |
422 | * Context: caller owns port_lock, and port_usb is set | |
423 | */ | |
424 | static unsigned gs_start_rx(struct gs_port *port) | |
425 | /* | |
426 | __releases(&port->port_lock) | |
427 | __acquires(&port->port_lock) | |
428 | */ | |
429 | { | |
430 | struct list_head *pool = &port->read_pool; | |
431 | struct usb_ep *out = port->port_usb->out; | |
c1dca562 DB |
432 | |
433 | while (!list_empty(pool)) { | |
434 | struct usb_request *req; | |
435 | int status; | |
436 | struct tty_struct *tty; | |
437 | ||
937ef73d | 438 | /* no more rx if closed */ |
35f95fd7 | 439 | tty = port->port.tty; |
937ef73d | 440 | if (!tty) |
c1dca562 DB |
441 | break; |
442 | ||
28609d40 JS |
443 | if (port->read_started >= QUEUE_SIZE) |
444 | break; | |
445 | ||
c1dca562 DB |
446 | req = list_entry(pool->next, struct usb_request, list); |
447 | list_del(&req->list); | |
448 | req->length = out->maxpacket; | |
449 | ||
450 | /* drop lock while we call out; the controller driver | |
451 | * may need to call us back (e.g. for disconnect) | |
452 | */ | |
453 | spin_unlock(&port->port_lock); | |
454 | status = usb_ep_queue(out, req, GFP_ATOMIC); | |
455 | spin_lock(&port->port_lock); | |
456 | ||
457 | if (status) { | |
458 | pr_debug("%s: %s %s err %d\n", | |
459 | __func__, "queue", out->name, status); | |
460 | list_add(&req->list, pool); | |
461 | break; | |
462 | } | |
28609d40 | 463 | port->read_started++; |
c1dca562 DB |
464 | |
465 | /* abort immediately after disconnect */ | |
466 | if (!port->port_usb) | |
467 | break; | |
468 | } | |
28609d40 | 469 | return port->read_started; |
c1dca562 DB |
470 | } |
471 | ||
937ef73d DB |
472 | /* |
473 | * RX tasklet takes data out of the RX queue and hands it up to the TTY | |
474 | * layer until it refuses to take any more data (or is throttled back). | |
475 | * Then it issues reads for any further data. | |
476 | * | |
477 | * If the RX queue becomes full enough that no usb_request is queued, | |
478 | * the OUT endpoint may begin NAKing as soon as its FIFO fills up. | |
479 | * So QUEUE_SIZE packets plus however many the FIFO holds (usually two) | |
480 | * can be buffered before the TTY layer's buffers (currently 64 KB). | |
481 | */ | |
482 | static void gs_rx_push(unsigned long _port) | |
c1dca562 | 483 | { |
937ef73d DB |
484 | struct gs_port *port = (void *)_port; |
485 | struct tty_struct *tty; | |
486 | struct list_head *queue = &port->read_queue; | |
487 | bool disconnect = false; | |
488 | bool do_push = false; | |
c1dca562 | 489 | |
937ef73d DB |
490 | /* hand any queued data to the tty */ |
491 | spin_lock_irq(&port->port_lock); | |
35f95fd7 | 492 | tty = port->port.tty; |
937ef73d DB |
493 | while (!list_empty(queue)) { |
494 | struct usb_request *req; | |
c1dca562 | 495 | |
937ef73d | 496 | req = list_first_entry(queue, struct usb_request, list); |
c1dca562 | 497 | |
937ef73d | 498 | /* leave data queued if tty was rx throttled */ |
05c7cd39 | 499 | if (tty && test_bit(TTY_THROTTLED, &tty->flags)) |
937ef73d DB |
500 | break; |
501 | ||
502 | switch (req->status) { | |
503 | case -ESHUTDOWN: | |
504 | disconnect = true; | |
505 | pr_vdebug(PREFIX "%d: shutdown\n", port->port_num); | |
506 | break; | |
507 | ||
508 | default: | |
509 | /* presumably a transient fault */ | |
510 | pr_warning(PREFIX "%d: unexpected RX status %d\n", | |
511 | port->port_num, req->status); | |
512 | /* FALLTHROUGH */ | |
513 | case 0: | |
514 | /* normal completion */ | |
515 | break; | |
516 | } | |
517 | ||
518 | /* push data to (open) tty */ | |
519 | if (req->actual) { | |
520 | char *packet = req->buf; | |
521 | unsigned size = req->actual; | |
522 | unsigned n; | |
523 | int count; | |
524 | ||
525 | /* we may have pushed part of this packet already... */ | |
526 | n = port->n_read; | |
527 | if (n) { | |
528 | packet += n; | |
529 | size -= n; | |
530 | } | |
531 | ||
05c7cd39 JS |
532 | count = tty_insert_flip_string(&port->port, packet, |
533 | size); | |
937ef73d DB |
534 | if (count) |
535 | do_push = true; | |
536 | if (count != size) { | |
537 | /* stop pushing; TTY layer can't handle more */ | |
538 | port->n_read += count; | |
539 | pr_vdebug(PREFIX "%d: rx block %d/%d\n", | |
540 | port->port_num, | |
541 | count, req->actual); | |
542 | break; | |
543 | } | |
544 | port->n_read = 0; | |
545 | } | |
05c7cd39 | 546 | |
937ef73d | 547 | list_move(&req->list, &port->read_pool); |
28609d40 | 548 | port->read_started--; |
937ef73d DB |
549 | } |
550 | ||
44a0c019 JP |
551 | /* Push from tty to ldisc; without low_latency set this is handled by |
552 | * a workqueue, so we won't get callbacks and can hold port_lock | |
937ef73d | 553 | */ |
2e124b4a JS |
554 | if (do_push) |
555 | tty_flip_buffer_push(&port->port); | |
937ef73d DB |
556 | |
557 | ||
558 | /* We want our data queue to become empty ASAP, keeping data | |
559 | * in the tty and ldisc (not here). If we couldn't push any | |
560 | * this time around, there may be trouble unless there's an | |
561 | * implicit tty_unthrottle() call on its way... | |
562 | * | |
563 | * REVISIT we should probably add a timer to keep the tasklet | |
564 | * from starving ... but it's not clear that case ever happens. | |
565 | */ | |
566 | if (!list_empty(queue) && tty) { | |
567 | if (!test_bit(TTY_THROTTLED, &tty->flags)) { | |
568 | if (do_push) | |
569 | tasklet_schedule(&port->push); | |
570 | else | |
571 | pr_warning(PREFIX "%d: RX not scheduled?\n", | |
572 | port->port_num); | |
573 | } | |
574 | } | |
575 | ||
576 | /* If we're still connected, refill the USB RX queue. */ | |
577 | if (!disconnect && port->port_usb) | |
578 | gs_start_rx(port); | |
579 | ||
580 | spin_unlock_irq(&port->port_lock); | |
581 | } | |
582 | ||
583 | static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) | |
584 | { | |
585 | struct gs_port *port = ep->driver_data; | |
586 | ||
587 | /* Queue all received data until the tty layer is ready for it. */ | |
588 | spin_lock(&port->port_lock); | |
589 | list_add_tail(&req->list, &port->read_queue); | |
590 | tasklet_schedule(&port->push); | |
c1dca562 DB |
591 | spin_unlock(&port->port_lock); |
592 | } | |
593 | ||
594 | static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) | |
595 | { | |
596 | struct gs_port *port = ep->driver_data; | |
597 | ||
598 | spin_lock(&port->port_lock); | |
599 | list_add(&req->list, &port->write_pool); | |
28609d40 | 600 | port->write_started--; |
c1dca562 DB |
601 | |
602 | switch (req->status) { | |
603 | default: | |
604 | /* presumably a transient fault */ | |
605 | pr_warning("%s: unexpected %s status %d\n", | |
606 | __func__, ep->name, req->status); | |
607 | /* FALL THROUGH */ | |
608 | case 0: | |
609 | /* normal completion */ | |
610 | gs_start_tx(port); | |
611 | break; | |
612 | ||
613 | case -ESHUTDOWN: | |
614 | /* disconnect */ | |
615 | pr_vdebug("%s: %s shutdown\n", __func__, ep->name); | |
616 | break; | |
617 | } | |
618 | ||
619 | spin_unlock(&port->port_lock); | |
620 | } | |
621 | ||
28609d40 JS |
622 | static void gs_free_requests(struct usb_ep *ep, struct list_head *head, |
623 | int *allocated) | |
c1dca562 DB |
624 | { |
625 | struct usb_request *req; | |
626 | ||
627 | while (!list_empty(head)) { | |
628 | req = list_entry(head->next, struct usb_request, list); | |
629 | list_del(&req->list); | |
630 | gs_free_req(ep, req); | |
28609d40 JS |
631 | if (allocated) |
632 | (*allocated)--; | |
c1dca562 DB |
633 | } |
634 | } | |
635 | ||
636 | static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, | |
28609d40 JS |
637 | void (*fn)(struct usb_ep *, struct usb_request *), |
638 | int *allocated) | |
c1dca562 DB |
639 | { |
640 | int i; | |
641 | struct usb_request *req; | |
28609d40 | 642 | int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE; |
c1dca562 DB |
643 | |
644 | /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't | |
645 | * do quite that many this time, don't fail ... we just won't | |
646 | * be as speedy as we might otherwise be. | |
647 | */ | |
28609d40 | 648 | for (i = 0; i < n; i++) { |
c1dca562 DB |
649 | req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); |
650 | if (!req) | |
651 | return list_empty(head) ? -ENOMEM : 0; | |
652 | req->complete = fn; | |
653 | list_add_tail(&req->list, head); | |
28609d40 JS |
654 | if (allocated) |
655 | (*allocated)++; | |
c1dca562 DB |
656 | } |
657 | return 0; | |
658 | } | |
659 | ||
660 | /** | |
661 | * gs_start_io - start USB I/O streams | |
662 | * @dev: encapsulates endpoints to use | |
663 | * Context: holding port_lock; port_tty and port_usb are non-null | |
664 | * | |
665 | * We only start I/O when something is connected to both sides of | |
666 | * this port. If nothing is listening on the host side, we may | |
667 | * be pointlessly filling up our TX buffers and FIFO. | |
668 | */ | |
669 | static int gs_start_io(struct gs_port *port) | |
670 | { | |
671 | struct list_head *head = &port->read_pool; | |
672 | struct usb_ep *ep = port->port_usb->out; | |
673 | int status; | |
674 | unsigned started; | |
675 | ||
676 | /* Allocate RX and TX I/O buffers. We can't easily do this much | |
677 | * earlier (with GFP_KERNEL) because the requests are coupled to | |
678 | * endpoints, as are the packet sizes we'll be using. Different | |
679 | * configurations may use different endpoints with a given port; | |
680 | * and high speed vs full speed changes packet sizes too. | |
681 | */ | |
28609d40 JS |
682 | status = gs_alloc_requests(ep, head, gs_read_complete, |
683 | &port->read_allocated); | |
c1dca562 DB |
684 | if (status) |
685 | return status; | |
686 | ||
687 | status = gs_alloc_requests(port->port_usb->in, &port->write_pool, | |
28609d40 | 688 | gs_write_complete, &port->write_allocated); |
c1dca562 | 689 | if (status) { |
28609d40 | 690 | gs_free_requests(ep, head, &port->read_allocated); |
c1dca562 DB |
691 | return status; |
692 | } | |
693 | ||
694 | /* queue read requests */ | |
937ef73d | 695 | port->n_read = 0; |
c1dca562 DB |
696 | started = gs_start_rx(port); |
697 | ||
698 | /* unblock any pending writes into our circular buffer */ | |
699 | if (started) { | |
35f95fd7 | 700 | tty_wakeup(port->port.tty); |
c1dca562 | 701 | } else { |
28609d40 JS |
702 | gs_free_requests(ep, head, &port->read_allocated); |
703 | gs_free_requests(port->port_usb->in, &port->write_pool, | |
704 | &port->write_allocated); | |
937ef73d | 705 | status = -EIO; |
c1dca562 DB |
706 | } |
707 | ||
937ef73d | 708 | return status; |
c1dca562 DB |
709 | } |
710 | ||
711 | /*-------------------------------------------------------------------------*/ | |
712 | ||
713 | /* TTY Driver */ | |
714 | ||
715 | /* | |
716 | * gs_open sets up the link between a gs_port and its associated TTY. | |
717 | * That link is broken *only* by TTY close(), and all driver methods | |
718 | * know that. | |
719 | */ | |
720 | static int gs_open(struct tty_struct *tty, struct file *file) | |
721 | { | |
722 | int port_num = tty->index; | |
723 | struct gs_port *port; | |
724 | int status; | |
725 | ||
c1dca562 DB |
726 | do { |
727 | mutex_lock(&ports[port_num].lock); | |
728 | port = ports[port_num].port; | |
729 | if (!port) | |
730 | status = -ENODEV; | |
731 | else { | |
732 | spin_lock_irq(&port->port_lock); | |
733 | ||
734 | /* already open? Great. */ | |
266e37ef | 735 | if (port->port.count) { |
c1dca562 | 736 | status = 0; |
266e37ef | 737 | port->port.count++; |
c1dca562 DB |
738 | |
739 | /* currently opening/closing? wait ... */ | |
740 | } else if (port->openclose) { | |
741 | status = -EBUSY; | |
742 | ||
743 | /* ... else we do the work */ | |
744 | } else { | |
745 | status = -EAGAIN; | |
746 | port->openclose = true; | |
747 | } | |
748 | spin_unlock_irq(&port->port_lock); | |
749 | } | |
750 | mutex_unlock(&ports[port_num].lock); | |
751 | ||
752 | switch (status) { | |
753 | default: | |
754 | /* fully handled */ | |
755 | return status; | |
756 | case -EAGAIN: | |
757 | /* must do the work */ | |
758 | break; | |
759 | case -EBUSY: | |
760 | /* wait for EAGAIN task to finish */ | |
761 | msleep(1); | |
762 | /* REVISIT could have a waitchannel here, if | |
763 | * concurrent open performance is important | |
764 | */ | |
765 | break; | |
766 | } | |
767 | } while (status != -EAGAIN); | |
768 | ||
769 | /* Do the "real open" */ | |
770 | spin_lock_irq(&port->port_lock); | |
771 | ||
772 | /* allocate circular buffer on first open */ | |
773 | if (port->port_write_buf.buf_buf == NULL) { | |
774 | ||
775 | spin_unlock_irq(&port->port_lock); | |
776 | status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE); | |
777 | spin_lock_irq(&port->port_lock); | |
778 | ||
779 | if (status) { | |
780 | pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n", | |
781 | port->port_num, tty, file); | |
782 | port->openclose = false; | |
783 | goto exit_unlock_port; | |
784 | } | |
785 | } | |
786 | ||
787 | /* REVISIT if REMOVED (ports[].port NULL), abort the open | |
788 | * to let rmmod work faster (but this way isn't wrong). | |
789 | */ | |
790 | ||
791 | /* REVISIT maybe wait for "carrier detect" */ | |
792 | ||
793 | tty->driver_data = port; | |
35f95fd7 | 794 | port->port.tty = tty; |
c1dca562 | 795 | |
266e37ef | 796 | port->port.count = 1; |
c1dca562 DB |
797 | port->openclose = false; |
798 | ||
c1dca562 DB |
799 | /* if connected, start the I/O stream */ |
800 | if (port->port_usb) { | |
1f1ba11b DB |
801 | struct gserial *gser = port->port_usb; |
802 | ||
c1dca562 DB |
803 | pr_debug("gs_open: start ttyGS%d\n", port->port_num); |
804 | gs_start_io(port); | |
805 | ||
1f1ba11b DB |
806 | if (gser->connect) |
807 | gser->connect(gser); | |
c1dca562 DB |
808 | } |
809 | ||
810 | pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); | |
811 | ||
812 | status = 0; | |
813 | ||
814 | exit_unlock_port: | |
815 | spin_unlock_irq(&port->port_lock); | |
816 | return status; | |
817 | } | |
818 | ||
819 | static int gs_writes_finished(struct gs_port *p) | |
820 | { | |
821 | int cond; | |
822 | ||
823 | /* return true on disconnect or empty buffer */ | |
824 | spin_lock_irq(&p->port_lock); | |
825 | cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf); | |
826 | spin_unlock_irq(&p->port_lock); | |
827 | ||
828 | return cond; | |
829 | } | |
830 | ||
831 | static void gs_close(struct tty_struct *tty, struct file *file) | |
832 | { | |
833 | struct gs_port *port = tty->driver_data; | |
1f1ba11b | 834 | struct gserial *gser; |
c1dca562 DB |
835 | |
836 | spin_lock_irq(&port->port_lock); | |
837 | ||
266e37ef JS |
838 | if (port->port.count != 1) { |
839 | if (port->port.count == 0) | |
c1dca562 DB |
840 | WARN_ON(1); |
841 | else | |
266e37ef | 842 | --port->port.count; |
c1dca562 DB |
843 | goto exit; |
844 | } | |
845 | ||
846 | pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); | |
847 | ||
848 | /* mark port as closing but in use; we can drop port lock | |
849 | * and sleep if necessary | |
850 | */ | |
851 | port->openclose = true; | |
266e37ef | 852 | port->port.count = 0; |
c1dca562 | 853 | |
1f1ba11b DB |
854 | gser = port->port_usb; |
855 | if (gser && gser->disconnect) | |
856 | gser->disconnect(gser); | |
c1dca562 DB |
857 | |
858 | /* wait for circular write buffer to drain, disconnect, or at | |
859 | * most GS_CLOSE_TIMEOUT seconds; then discard the rest | |
860 | */ | |
1f1ba11b | 861 | if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) { |
c1dca562 DB |
862 | spin_unlock_irq(&port->port_lock); |
863 | wait_event_interruptible_timeout(port->drain_wait, | |
864 | gs_writes_finished(port), | |
865 | GS_CLOSE_TIMEOUT * HZ); | |
866 | spin_lock_irq(&port->port_lock); | |
1f1ba11b | 867 | gser = port->port_usb; |
c1dca562 DB |
868 | } |
869 | ||
870 | /* Iff we're disconnected, there can be no I/O in flight so it's | |
871 | * ok to free the circular buffer; else just scrub it. And don't | |
872 | * let the push tasklet fire again until we're re-opened. | |
873 | */ | |
1f1ba11b | 874 | if (gser == NULL) |
c1dca562 DB |
875 | gs_buf_free(&port->port_write_buf); |
876 | else | |
877 | gs_buf_clear(&port->port_write_buf); | |
878 | ||
c1dca562 | 879 | tty->driver_data = NULL; |
35f95fd7 | 880 | port->port.tty = NULL; |
c1dca562 DB |
881 | |
882 | port->openclose = false; | |
883 | ||
884 | pr_debug("gs_close: ttyGS%d (%p,%p) done!\n", | |
885 | port->port_num, tty, file); | |
886 | ||
3d5ea59d | 887 | wake_up_interruptible(&port->port.close_wait); |
c1dca562 DB |
888 | exit: |
889 | spin_unlock_irq(&port->port_lock); | |
890 | } | |
891 | ||
892 | static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
893 | { | |
894 | struct gs_port *port = tty->driver_data; | |
895 | unsigned long flags; | |
896 | int status; | |
897 | ||
898 | pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n", | |
899 | port->port_num, tty, count); | |
900 | ||
901 | spin_lock_irqsave(&port->port_lock, flags); | |
902 | if (count) | |
903 | count = gs_buf_put(&port->port_write_buf, buf, count); | |
904 | /* treat count == 0 as flush_chars() */ | |
905 | if (port->port_usb) | |
906 | status = gs_start_tx(port); | |
907 | spin_unlock_irqrestore(&port->port_lock, flags); | |
908 | ||
909 | return count; | |
910 | } | |
911 | ||
912 | static int gs_put_char(struct tty_struct *tty, unsigned char ch) | |
913 | { | |
914 | struct gs_port *port = tty->driver_data; | |
915 | unsigned long flags; | |
916 | int status; | |
917 | ||
bfa346ad | 918 | pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %pf\n", |
c1dca562 DB |
919 | port->port_num, tty, ch, __builtin_return_address(0)); |
920 | ||
921 | spin_lock_irqsave(&port->port_lock, flags); | |
922 | status = gs_buf_put(&port->port_write_buf, &ch, 1); | |
923 | spin_unlock_irqrestore(&port->port_lock, flags); | |
924 | ||
925 | return status; | |
926 | } | |
927 | ||
928 | static void gs_flush_chars(struct tty_struct *tty) | |
929 | { | |
930 | struct gs_port *port = tty->driver_data; | |
931 | unsigned long flags; | |
932 | ||
933 | pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty); | |
934 | ||
935 | spin_lock_irqsave(&port->port_lock, flags); | |
936 | if (port->port_usb) | |
937 | gs_start_tx(port); | |
938 | spin_unlock_irqrestore(&port->port_lock, flags); | |
939 | } | |
940 | ||
941 | static int gs_write_room(struct tty_struct *tty) | |
942 | { | |
943 | struct gs_port *port = tty->driver_data; | |
944 | unsigned long flags; | |
945 | int room = 0; | |
946 | ||
947 | spin_lock_irqsave(&port->port_lock, flags); | |
948 | if (port->port_usb) | |
949 | room = gs_buf_space_avail(&port->port_write_buf); | |
950 | spin_unlock_irqrestore(&port->port_lock, flags); | |
951 | ||
952 | pr_vdebug("gs_write_room: (%d,%p) room=%d\n", | |
953 | port->port_num, tty, room); | |
954 | ||
955 | return room; | |
956 | } | |
957 | ||
958 | static int gs_chars_in_buffer(struct tty_struct *tty) | |
959 | { | |
960 | struct gs_port *port = tty->driver_data; | |
961 | unsigned long flags; | |
962 | int chars = 0; | |
963 | ||
964 | spin_lock_irqsave(&port->port_lock, flags); | |
965 | chars = gs_buf_data_avail(&port->port_write_buf); | |
966 | spin_unlock_irqrestore(&port->port_lock, flags); | |
967 | ||
968 | pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n", | |
969 | port->port_num, tty, chars); | |
970 | ||
971 | return chars; | |
972 | } | |
973 | ||
974 | /* undo side effects of setting TTY_THROTTLED */ | |
975 | static void gs_unthrottle(struct tty_struct *tty) | |
976 | { | |
977 | struct gs_port *port = tty->driver_data; | |
978 | unsigned long flags; | |
c1dca562 DB |
979 | |
980 | spin_lock_irqsave(&port->port_lock, flags); | |
937ef73d DB |
981 | if (port->port_usb) { |
982 | /* Kickstart read queue processing. We don't do xon/xoff, | |
983 | * rts/cts, or other handshaking with the host, but if the | |
984 | * read queue backs up enough we'll be NAKing OUT packets. | |
985 | */ | |
986 | tasklet_schedule(&port->push); | |
987 | pr_vdebug(PREFIX "%d: unthrottle\n", port->port_num); | |
988 | } | |
c1dca562 | 989 | spin_unlock_irqrestore(&port->port_lock, flags); |
c1dca562 DB |
990 | } |
991 | ||
1f1ba11b DB |
992 | static int gs_break_ctl(struct tty_struct *tty, int duration) |
993 | { | |
994 | struct gs_port *port = tty->driver_data; | |
995 | int status = 0; | |
996 | struct gserial *gser; | |
997 | ||
998 | pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n", | |
999 | port->port_num, duration); | |
1000 | ||
1001 | spin_lock_irq(&port->port_lock); | |
1002 | gser = port->port_usb; | |
1003 | if (gser && gser->send_break) | |
1004 | status = gser->send_break(gser, duration); | |
1005 | spin_unlock_irq(&port->port_lock); | |
1006 | ||
1007 | return status; | |
1008 | } | |
1009 | ||
c1dca562 DB |
1010 | static const struct tty_operations gs_tty_ops = { |
1011 | .open = gs_open, | |
1012 | .close = gs_close, | |
1013 | .write = gs_write, | |
1014 | .put_char = gs_put_char, | |
1015 | .flush_chars = gs_flush_chars, | |
1016 | .write_room = gs_write_room, | |
1017 | .chars_in_buffer = gs_chars_in_buffer, | |
1018 | .unthrottle = gs_unthrottle, | |
1f1ba11b | 1019 | .break_ctl = gs_break_ctl, |
c1dca562 DB |
1020 | }; |
1021 | ||
1022 | /*-------------------------------------------------------------------------*/ | |
1023 | ||
1024 | static struct tty_driver *gs_tty_driver; | |
1025 | ||
c3c04b29 | 1026 | static int |
c1dca562 DB |
1027 | gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) |
1028 | { | |
1029 | struct gs_port *port; | |
1030 | ||
1031 | port = kzalloc(sizeof(struct gs_port), GFP_KERNEL); | |
1032 | if (port == NULL) | |
1033 | return -ENOMEM; | |
1034 | ||
266e37ef | 1035 | tty_port_init(&port->port); |
c1dca562 | 1036 | spin_lock_init(&port->port_lock); |
c1dca562 DB |
1037 | init_waitqueue_head(&port->drain_wait); |
1038 | ||
1039 | tasklet_init(&port->push, gs_rx_push, (unsigned long) port); | |
1040 | ||
1041 | INIT_LIST_HEAD(&port->read_pool); | |
937ef73d | 1042 | INIT_LIST_HEAD(&port->read_queue); |
c1dca562 DB |
1043 | INIT_LIST_HEAD(&port->write_pool); |
1044 | ||
1045 | port->port_num = port_num; | |
1046 | port->port_line_coding = *coding; | |
1047 | ||
1048 | ports[port_num].port = port; | |
1049 | ||
1050 | return 0; | |
1051 | } | |
1052 | ||
1053 | /** | |
1054 | * gserial_setup - initialize TTY driver for one or more ports | |
1055 | * @g: gadget to associate with these ports | |
1056 | * @count: how many ports to support | |
1057 | * Context: may sleep | |
1058 | * | |
1059 | * The TTY stack needs to know in advance how many devices it should | |
1060 | * plan to manage. Use this call to set up the ports you will be | |
1061 | * exporting through USB. Later, connect them to functions based | |
1062 | * on what configuration is activated by the USB host; and disconnect | |
1063 | * them as appropriate. | |
1064 | * | |
1065 | * An example would be a two-configuration device in which both | |
1066 | * configurations expose port 0, but through different functions. | |
1067 | * One configuration could even expose port 1 while the other | |
1068 | * one doesn't. | |
1069 | * | |
1070 | * Returns negative errno or zero. | |
1071 | */ | |
c3c04b29 | 1072 | int gserial_setup(struct usb_gadget *g, unsigned count) |
c1dca562 DB |
1073 | { |
1074 | unsigned i; | |
1075 | struct usb_cdc_line_coding coding; | |
1076 | int status; | |
1077 | ||
1078 | if (count == 0 || count > N_PORTS) | |
1079 | return -EINVAL; | |
1080 | ||
1081 | gs_tty_driver = alloc_tty_driver(count); | |
1082 | if (!gs_tty_driver) | |
1083 | return -ENOMEM; | |
1084 | ||
c1dca562 | 1085 | gs_tty_driver->driver_name = "g_serial"; |
937ef73d | 1086 | gs_tty_driver->name = PREFIX; |
c1dca562 DB |
1087 | /* uses dynamically assigned dev_t values */ |
1088 | ||
1089 | gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
1090 | gs_tty_driver->subtype = SERIAL_TYPE_NORMAL; | |
1091 | gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; | |
1092 | gs_tty_driver->init_termios = tty_std_termios; | |
1093 | ||
1094 | /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on | |
1095 | * MS-Windows. Otherwise, most of these flags shouldn't affect | |
1096 | * anything unless we were to actually hook up to a serial line. | |
1097 | */ | |
1098 | gs_tty_driver->init_termios.c_cflag = | |
1099 | B9600 | CS8 | CREAD | HUPCL | CLOCAL; | |
1100 | gs_tty_driver->init_termios.c_ispeed = 9600; | |
1101 | gs_tty_driver->init_termios.c_ospeed = 9600; | |
1102 | ||
551509d2 | 1103 | coding.dwDTERate = cpu_to_le32(9600); |
c1dca562 DB |
1104 | coding.bCharFormat = 8; |
1105 | coding.bParityType = USB_CDC_NO_PARITY; | |
1106 | coding.bDataBits = USB_CDC_1_STOP_BITS; | |
1107 | ||
1108 | tty_set_operations(gs_tty_driver, &gs_tty_ops); | |
1109 | ||
1110 | /* make devices be openable */ | |
1111 | for (i = 0; i < count; i++) { | |
1112 | mutex_init(&ports[i].lock); | |
1113 | status = gs_port_alloc(i, &coding); | |
1114 | if (status) { | |
1115 | count = i; | |
1116 | goto fail; | |
1117 | } | |
1118 | } | |
1119 | n_ports = count; | |
1120 | ||
1121 | /* export the driver ... */ | |
1122 | status = tty_register_driver(gs_tty_driver); | |
1123 | if (status) { | |
c1dca562 DB |
1124 | pr_err("%s: cannot register, err %d\n", |
1125 | __func__, status); | |
1126 | goto fail; | |
1127 | } | |
1128 | ||
1129 | /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */ | |
1130 | for (i = 0; i < count; i++) { | |
1131 | struct device *tty_dev; | |
1132 | ||
734cc178 JS |
1133 | tty_dev = tty_port_register_device(&ports[i].port->port, |
1134 | gs_tty_driver, i, &g->dev); | |
c1dca562 DB |
1135 | if (IS_ERR(tty_dev)) |
1136 | pr_warning("%s: no classdev for port %d, err %ld\n", | |
1137 | __func__, i, PTR_ERR(tty_dev)); | |
1138 | } | |
1139 | ||
1140 | pr_debug("%s: registered %d ttyGS* device%s\n", __func__, | |
1141 | count, (count == 1) ? "" : "s"); | |
1142 | ||
1143 | return status; | |
1144 | fail: | |
191c5f10 JS |
1145 | while (count--) { |
1146 | tty_port_destroy(&ports[count].port->port); | |
c1dca562 | 1147 | kfree(ports[count].port); |
191c5f10 | 1148 | } |
c1dca562 DB |
1149 | put_tty_driver(gs_tty_driver); |
1150 | gs_tty_driver = NULL; | |
1151 | return status; | |
1152 | } | |
1153 | ||
1154 | static int gs_closed(struct gs_port *port) | |
1155 | { | |
1156 | int cond; | |
1157 | ||
1158 | spin_lock_irq(&port->port_lock); | |
266e37ef | 1159 | cond = (port->port.count == 0) && !port->openclose; |
c1dca562 DB |
1160 | spin_unlock_irq(&port->port_lock); |
1161 | return cond; | |
1162 | } | |
1163 | ||
1164 | /** | |
1165 | * gserial_cleanup - remove TTY-over-USB driver and devices | |
1166 | * Context: may sleep | |
1167 | * | |
1168 | * This is called to free all resources allocated by @gserial_setup(). | |
1169 | * Accordingly, it may need to wait until some open /dev/ files have | |
1170 | * closed. | |
1171 | * | |
1172 | * The caller must have issued @gserial_disconnect() for any ports | |
1173 | * that had previously been connected, so that there is never any | |
1174 | * I/O pending when it's called. | |
1175 | */ | |
1176 | void gserial_cleanup(void) | |
1177 | { | |
1178 | unsigned i; | |
1179 | struct gs_port *port; | |
1180 | ||
ac90e365 DB |
1181 | if (!gs_tty_driver) |
1182 | return; | |
1183 | ||
c1dca562 DB |
1184 | /* start sysfs and /dev/ttyGS* node removal */ |
1185 | for (i = 0; i < n_ports; i++) | |
1186 | tty_unregister_device(gs_tty_driver, i); | |
1187 | ||
1188 | for (i = 0; i < n_ports; i++) { | |
1189 | /* prevent new opens */ | |
1190 | mutex_lock(&ports[i].lock); | |
1191 | port = ports[i].port; | |
1192 | ports[i].port = NULL; | |
1193 | mutex_unlock(&ports[i].lock); | |
1194 | ||
937ef73d DB |
1195 | tasklet_kill(&port->push); |
1196 | ||
c1dca562 | 1197 | /* wait for old opens to finish */ |
3d5ea59d | 1198 | wait_event(port->port.close_wait, gs_closed(port)); |
c1dca562 DB |
1199 | |
1200 | WARN_ON(port->port_usb != NULL); | |
1201 | ||
191c5f10 | 1202 | tty_port_destroy(&port->port); |
c1dca562 DB |
1203 | kfree(port); |
1204 | } | |
1205 | n_ports = 0; | |
1206 | ||
1207 | tty_unregister_driver(gs_tty_driver); | |
b23097b7 | 1208 | put_tty_driver(gs_tty_driver); |
c1dca562 DB |
1209 | gs_tty_driver = NULL; |
1210 | ||
1211 | pr_debug("%s: cleaned up ttyGS* support\n", __func__); | |
1212 | } | |
1213 | ||
1214 | /** | |
1215 | * gserial_connect - notify TTY I/O glue that USB link is active | |
1216 | * @gser: the function, set up with endpoints and descriptors | |
1217 | * @port_num: which port is active | |
1218 | * Context: any (usually from irq) | |
1219 | * | |
1220 | * This is called activate endpoints and let the TTY layer know that | |
1221 | * the connection is active ... not unlike "carrier detect". It won't | |
1222 | * necessarily start I/O queues; unless the TTY is held open by any | |
1223 | * task, there would be no point. However, the endpoints will be | |
1224 | * activated so the USB host can perform I/O, subject to basic USB | |
1225 | * hardware flow control. | |
1226 | * | |
1227 | * Caller needs to have set up the endpoints and USB function in @dev | |
1228 | * before calling this, as well as the appropriate (speed-specific) | |
1229 | * endpoint descriptors, and also have set up the TTY driver by calling | |
1230 | * @gserial_setup(). | |
1231 | * | |
1232 | * Returns negative errno or zero. | |
1233 | * On success, ep->driver_data will be overwritten. | |
1234 | */ | |
1235 | int gserial_connect(struct gserial *gser, u8 port_num) | |
1236 | { | |
1237 | struct gs_port *port; | |
1238 | unsigned long flags; | |
1239 | int status; | |
1240 | ||
1241 | if (!gs_tty_driver || port_num >= n_ports) | |
1242 | return -ENXIO; | |
1243 | ||
1244 | /* we "know" gserial_cleanup() hasn't been called */ | |
1245 | port = ports[port_num].port; | |
1246 | ||
1247 | /* activate the endpoints */ | |
72c973dd | 1248 | status = usb_ep_enable(gser->in); |
c1dca562 DB |
1249 | if (status < 0) |
1250 | return status; | |
1251 | gser->in->driver_data = port; | |
1252 | ||
72c973dd | 1253 | status = usb_ep_enable(gser->out); |
c1dca562 DB |
1254 | if (status < 0) |
1255 | goto fail_out; | |
1256 | gser->out->driver_data = port; | |
1257 | ||
1258 | /* then tell the tty glue that I/O can work */ | |
1259 | spin_lock_irqsave(&port->port_lock, flags); | |
1260 | gser->ioport = port; | |
1261 | port->port_usb = gser; | |
1262 | ||
1263 | /* REVISIT unclear how best to handle this state... | |
1264 | * we don't really couple it with the Linux TTY. | |
1265 | */ | |
1266 | gser->port_line_coding = port->port_line_coding; | |
1267 | ||
1268 | /* REVISIT if waiting on "carrier detect", signal. */ | |
1269 | ||
1f1ba11b DB |
1270 | /* if it's already open, start I/O ... and notify the serial |
1271 | * protocol about open/close status (connect/disconnect). | |
c1dca562 | 1272 | */ |
266e37ef | 1273 | if (port->port.count) { |
c1dca562 DB |
1274 | pr_debug("gserial_connect: start ttyGS%d\n", port->port_num); |
1275 | gs_start_io(port); | |
1f1ba11b DB |
1276 | if (gser->connect) |
1277 | gser->connect(gser); | |
1278 | } else { | |
1279 | if (gser->disconnect) | |
1280 | gser->disconnect(gser); | |
c1dca562 DB |
1281 | } |
1282 | ||
1283 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1284 | ||
1285 | return status; | |
1286 | ||
1287 | fail_out: | |
1288 | usb_ep_disable(gser->in); | |
1289 | gser->in->driver_data = NULL; | |
1290 | return status; | |
1291 | } | |
1292 | ||
1293 | /** | |
1294 | * gserial_disconnect - notify TTY I/O glue that USB link is inactive | |
1295 | * @gser: the function, on which gserial_connect() was called | |
1296 | * Context: any (usually from irq) | |
1297 | * | |
1298 | * This is called to deactivate endpoints and let the TTY layer know | |
1299 | * that the connection went inactive ... not unlike "hangup". | |
1300 | * | |
1301 | * On return, the state is as if gserial_connect() had never been called; | |
1302 | * there is no active USB I/O on these endpoints. | |
1303 | */ | |
1304 | void gserial_disconnect(struct gserial *gser) | |
1305 | { | |
1306 | struct gs_port *port = gser->ioport; | |
1307 | unsigned long flags; | |
1308 | ||
1309 | if (!port) | |
1310 | return; | |
1311 | ||
1312 | /* tell the TTY glue not to do I/O here any more */ | |
1313 | spin_lock_irqsave(&port->port_lock, flags); | |
1314 | ||
1315 | /* REVISIT as above: how best to track this? */ | |
1316 | port->port_line_coding = gser->port_line_coding; | |
1317 | ||
1318 | port->port_usb = NULL; | |
1319 | gser->ioport = NULL; | |
266e37ef | 1320 | if (port->port.count > 0 || port->openclose) { |
c1dca562 | 1321 | wake_up_interruptible(&port->drain_wait); |
35f95fd7 JS |
1322 | if (port->port.tty) |
1323 | tty_hangup(port->port.tty); | |
c1dca562 DB |
1324 | } |
1325 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1326 | ||
1327 | /* disable endpoints, aborting down any active I/O */ | |
1328 | usb_ep_disable(gser->out); | |
1329 | gser->out->driver_data = NULL; | |
1330 | ||
1331 | usb_ep_disable(gser->in); | |
1332 | gser->in->driver_data = NULL; | |
1333 | ||
1334 | /* finally, free any unused/unusable I/O buffers */ | |
1335 | spin_lock_irqsave(&port->port_lock, flags); | |
266e37ef | 1336 | if (port->port.count == 0 && !port->openclose) |
c1dca562 | 1337 | gs_buf_free(&port->port_write_buf); |
28609d40 JS |
1338 | gs_free_requests(gser->out, &port->read_pool, NULL); |
1339 | gs_free_requests(gser->out, &port->read_queue, NULL); | |
1340 | gs_free_requests(gser->in, &port->write_pool, NULL); | |
1341 | ||
1342 | port->read_allocated = port->read_started = | |
1343 | port->write_allocated = port->write_started = 0; | |
1344 | ||
c1dca562 DB |
1345 | spin_unlock_irqrestore(&port->port_lock, flags); |
1346 | } |