Commit | Line | Data |
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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> |
3249ca22 | 29 | #include <linux/module.h> |
c1dca562 DB |
30 | |
31 | #include "u_serial.h" | |
32 | ||
33 | ||
34 | /* | |
35 | * This component encapsulates the TTY layer glue needed to provide basic | |
36 | * "serial port" functionality through the USB gadget stack. Each such | |
37 | * port is exposed through a /dev/ttyGS* node. | |
38 | * | |
19b10a88 SAS |
39 | * After this module has been loaded, the individual TTY port can be requested |
40 | * (gserial_alloc_line()) and it will stay available until they are removed | |
41 | * (gserial_free_line()). Each one may be connected to a USB function | |
42 | * (gserial_connect), or disconnected (with gserial_disconnect) when the USB | |
43 | * host issues a config change event. Data can only flow when the port is | |
44 | * connected to the host. | |
c1dca562 DB |
45 | * |
46 | * A given TTY port can be made available in multiple configurations. | |
47 | * For example, each one might expose a ttyGS0 node which provides a | |
48 | * login application. In one case that might use CDC ACM interface 0, | |
49 | * while another configuration might use interface 3 for that. The | |
50 | * work to handle that (including descriptor management) is not part | |
51 | * of this component. | |
52 | * | |
53 | * Configurations may expose more than one TTY port. For example, if | |
54 | * ttyGS0 provides login service, then ttyGS1 might provide dialer access | |
55 | * for a telephone or fax link. And ttyGS2 might be something that just | |
56 | * needs a simple byte stream interface for some messaging protocol that | |
57 | * is managed in userspace ... OBEX, PTP, and MTP have been mentioned. | |
58 | */ | |
59 | ||
937ef73d DB |
60 | #define PREFIX "ttyGS" |
61 | ||
c1dca562 DB |
62 | /* |
63 | * gserial is the lifecycle interface, used by USB functions | |
64 | * gs_port is the I/O nexus, used by the tty driver | |
65 | * tty_struct links to the tty/filesystem framework | |
66 | * | |
67 | * gserial <---> gs_port ... links will be null when the USB link is | |
1f1ba11b DB |
68 | * inactive; managed by gserial_{connect,disconnect}(). each gserial |
69 | * instance can wrap its own USB control protocol. | |
c1dca562 DB |
70 | * gserial->ioport == usb_ep->driver_data ... gs_port |
71 | * gs_port->port_usb ... gserial | |
72 | * | |
73 | * gs_port <---> tty_struct ... links will be null when the TTY file | |
74 | * isn't opened; managed by gs_open()/gs_close() | |
75 | * gserial->port_tty ... tty_struct | |
76 | * tty_struct->driver_data ... gserial | |
77 | */ | |
78 | ||
79 | /* RX and TX queues can buffer QUEUE_SIZE packets before they hit the | |
80 | * next layer of buffering. For TX that's a circular buffer; for RX | |
81 | * consider it a NOP. A third layer is provided by the TTY code. | |
82 | */ | |
83 | #define QUEUE_SIZE 16 | |
84 | #define WRITE_BUF_SIZE 8192 /* TX only */ | |
85 | ||
86 | /* circular buffer */ | |
87 | struct gs_buf { | |
88 | unsigned buf_size; | |
89 | char *buf_buf; | |
90 | char *buf_get; | |
91 | char *buf_put; | |
92 | }; | |
93 | ||
94 | /* | |
95 | * The port structure holds info for each port, one for each minor number | |
96 | * (and thus for each /dev/ node). | |
97 | */ | |
98 | struct gs_port { | |
266e37ef | 99 | struct tty_port port; |
c1dca562 DB |
100 | spinlock_t port_lock; /* guard port_* access */ |
101 | ||
102 | struct gserial *port_usb; | |
c1dca562 | 103 | |
c1dca562 DB |
104 | bool openclose; /* open/close in progress */ |
105 | u8 port_num; | |
106 | ||
c1dca562 | 107 | struct list_head read_pool; |
28609d40 JS |
108 | int read_started; |
109 | int read_allocated; | |
937ef73d DB |
110 | struct list_head read_queue; |
111 | unsigned n_read; | |
c1dca562 DB |
112 | struct tasklet_struct push; |
113 | ||
114 | struct list_head write_pool; | |
28609d40 JS |
115 | int write_started; |
116 | int write_allocated; | |
c1dca562 DB |
117 | struct gs_buf port_write_buf; |
118 | wait_queue_head_t drain_wait; /* wait while writes drain */ | |
119 | ||
120 | /* REVISIT this state ... */ | |
121 | struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */ | |
122 | }; | |
123 | ||
c1dca562 DB |
124 | static struct portmaster { |
125 | struct mutex lock; /* protect open/close */ | |
126 | struct gs_port *port; | |
19b10a88 | 127 | } ports[MAX_U_SERIAL_PORTS]; |
c1dca562 DB |
128 | |
129 | #define GS_CLOSE_TIMEOUT 15 /* seconds */ | |
130 | ||
131 | ||
132 | ||
133 | #ifdef VERBOSE_DEBUG | |
ea0e6276 | 134 | #ifndef pr_vdebug |
c1dca562 DB |
135 | #define pr_vdebug(fmt, arg...) \ |
136 | pr_debug(fmt, ##arg) | |
ea0e6276 | 137 | #endif /* pr_vdebug */ |
c1dca562 | 138 | #else |
273daf2f | 139 | #ifndef pr_vdebug |
c1dca562 DB |
140 | #define pr_vdebug(fmt, arg...) \ |
141 | ({ if (0) pr_debug(fmt, ##arg); }) | |
ea0e6276 | 142 | #endif /* pr_vdebug */ |
c1dca562 DB |
143 | #endif |
144 | ||
145 | /*-------------------------------------------------------------------------*/ | |
146 | ||
147 | /* Circular Buffer */ | |
148 | ||
149 | /* | |
150 | * gs_buf_alloc | |
151 | * | |
152 | * Allocate a circular buffer and all associated memory. | |
153 | */ | |
154 | static int gs_buf_alloc(struct gs_buf *gb, unsigned size) | |
155 | { | |
156 | gb->buf_buf = kmalloc(size, GFP_KERNEL); | |
157 | if (gb->buf_buf == NULL) | |
158 | return -ENOMEM; | |
159 | ||
160 | gb->buf_size = size; | |
161 | gb->buf_put = gb->buf_buf; | |
162 | gb->buf_get = gb->buf_buf; | |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
167 | /* | |
168 | * gs_buf_free | |
169 | * | |
170 | * Free the buffer and all associated memory. | |
171 | */ | |
172 | static void gs_buf_free(struct gs_buf *gb) | |
173 | { | |
174 | kfree(gb->buf_buf); | |
175 | gb->buf_buf = NULL; | |
176 | } | |
177 | ||
178 | /* | |
179 | * gs_buf_clear | |
180 | * | |
181 | * Clear out all data in the circular buffer. | |
182 | */ | |
183 | static void gs_buf_clear(struct gs_buf *gb) | |
184 | { | |
185 | gb->buf_get = gb->buf_put; | |
186 | /* equivalent to a get of all data available */ | |
187 | } | |
188 | ||
189 | /* | |
190 | * gs_buf_data_avail | |
191 | * | |
1f1ba11b | 192 | * Return the number of bytes of data written into the circular |
c1dca562 DB |
193 | * buffer. |
194 | */ | |
195 | static unsigned gs_buf_data_avail(struct gs_buf *gb) | |
196 | { | |
197 | return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size; | |
198 | } | |
199 | ||
200 | /* | |
201 | * gs_buf_space_avail | |
202 | * | |
203 | * Return the number of bytes of space available in the circular | |
204 | * buffer. | |
205 | */ | |
206 | static unsigned gs_buf_space_avail(struct gs_buf *gb) | |
207 | { | |
208 | return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size; | |
209 | } | |
210 | ||
211 | /* | |
212 | * gs_buf_put | |
213 | * | |
214 | * Copy data data from a user buffer and put it into the circular buffer. | |
215 | * Restrict to the amount of space available. | |
216 | * | |
217 | * Return the number of bytes copied. | |
218 | */ | |
219 | static unsigned | |
220 | gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count) | |
221 | { | |
222 | unsigned len; | |
223 | ||
224 | len = gs_buf_space_avail(gb); | |
225 | if (count > len) | |
226 | count = len; | |
227 | ||
228 | if (count == 0) | |
229 | return 0; | |
230 | ||
231 | len = gb->buf_buf + gb->buf_size - gb->buf_put; | |
232 | if (count > len) { | |
233 | memcpy(gb->buf_put, buf, len); | |
234 | memcpy(gb->buf_buf, buf+len, count - len); | |
235 | gb->buf_put = gb->buf_buf + count - len; | |
236 | } else { | |
237 | memcpy(gb->buf_put, buf, count); | |
238 | if (count < len) | |
239 | gb->buf_put += count; | |
240 | else /* count == len */ | |
241 | gb->buf_put = gb->buf_buf; | |
242 | } | |
243 | ||
244 | return count; | |
245 | } | |
246 | ||
247 | /* | |
248 | * gs_buf_get | |
249 | * | |
250 | * Get data from the circular buffer and copy to the given buffer. | |
251 | * Restrict to the amount of data available. | |
252 | * | |
253 | * Return the number of bytes copied. | |
254 | */ | |
255 | static unsigned | |
256 | gs_buf_get(struct gs_buf *gb, char *buf, unsigned count) | |
257 | { | |
258 | unsigned len; | |
259 | ||
260 | len = gs_buf_data_avail(gb); | |
261 | if (count > len) | |
262 | count = len; | |
263 | ||
264 | if (count == 0) | |
265 | return 0; | |
266 | ||
267 | len = gb->buf_buf + gb->buf_size - gb->buf_get; | |
268 | if (count > len) { | |
269 | memcpy(buf, gb->buf_get, len); | |
270 | memcpy(buf+len, gb->buf_buf, count - len); | |
271 | gb->buf_get = gb->buf_buf + count - len; | |
272 | } else { | |
273 | memcpy(buf, gb->buf_get, count); | |
274 | if (count < len) | |
275 | gb->buf_get += count; | |
276 | else /* count == len */ | |
277 | gb->buf_get = gb->buf_buf; | |
278 | } | |
279 | ||
280 | return count; | |
281 | } | |
282 | ||
283 | /*-------------------------------------------------------------------------*/ | |
284 | ||
285 | /* I/O glue between TTY (upper) and USB function (lower) driver layers */ | |
286 | ||
287 | /* | |
288 | * gs_alloc_req | |
289 | * | |
290 | * Allocate a usb_request and its buffer. Returns a pointer to the | |
291 | * usb_request or NULL if there is an error. | |
292 | */ | |
1f1ba11b | 293 | struct usb_request * |
c1dca562 DB |
294 | gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) |
295 | { | |
296 | struct usb_request *req; | |
297 | ||
298 | req = usb_ep_alloc_request(ep, kmalloc_flags); | |
299 | ||
300 | if (req != NULL) { | |
301 | req->length = len; | |
302 | req->buf = kmalloc(len, kmalloc_flags); | |
303 | if (req->buf == NULL) { | |
304 | usb_ep_free_request(ep, req); | |
305 | return NULL; | |
306 | } | |
307 | } | |
308 | ||
309 | return req; | |
310 | } | |
3249ca22 | 311 | EXPORT_SYMBOL_GPL(gs_alloc_req); |
c1dca562 DB |
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 | } | |
3249ca22 | 323 | EXPORT_SYMBOL_GPL(gs_free_req); |
c1dca562 DB |
324 | |
325 | /* | |
326 | * gs_send_packet | |
327 | * | |
328 | * If there is data to send, a packet is built in the given | |
329 | * buffer and the size is returned. If there is no data to | |
330 | * send, 0 is returned. | |
331 | * | |
332 | * Called with port_lock held. | |
333 | */ | |
334 | static unsigned | |
335 | gs_send_packet(struct gs_port *port, char *packet, unsigned size) | |
336 | { | |
337 | unsigned len; | |
338 | ||
339 | len = gs_buf_data_avail(&port->port_write_buf); | |
340 | if (len < size) | |
341 | size = len; | |
342 | if (size != 0) | |
343 | size = gs_buf_get(&port->port_write_buf, packet, size); | |
344 | return size; | |
345 | } | |
346 | ||
347 | /* | |
348 | * gs_start_tx | |
349 | * | |
350 | * This function finds available write requests, calls | |
351 | * gs_send_packet to fill these packets with data, and | |
352 | * continues until either there are no more write requests | |
353 | * available or no more data to send. This function is | |
354 | * run whenever data arrives or write requests are available. | |
355 | * | |
356 | * Context: caller owns port_lock; port_usb is non-null. | |
357 | */ | |
358 | static int gs_start_tx(struct gs_port *port) | |
359 | /* | |
360 | __releases(&port->port_lock) | |
361 | __acquires(&port->port_lock) | |
362 | */ | |
363 | { | |
364 | struct list_head *pool = &port->write_pool; | |
365 | struct usb_ep *in = port->port_usb->in; | |
366 | int status = 0; | |
367 | bool do_tty_wake = false; | |
368 | ||
369 | while (!list_empty(pool)) { | |
370 | struct usb_request *req; | |
371 | int len; | |
372 | ||
28609d40 JS |
373 | if (port->write_started >= QUEUE_SIZE) |
374 | break; | |
375 | ||
c1dca562 DB |
376 | req = list_entry(pool->next, struct usb_request, list); |
377 | len = gs_send_packet(port, req->buf, in->maxpacket); | |
378 | if (len == 0) { | |
379 | wake_up_interruptible(&port->drain_wait); | |
380 | break; | |
381 | } | |
382 | do_tty_wake = true; | |
383 | ||
384 | req->length = len; | |
385 | list_del(&req->list); | |
2e251341 | 386 | req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0); |
c1dca562 | 387 | |
937ef73d DB |
388 | pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n", |
389 | port->port_num, len, *((u8 *)req->buf), | |
c1dca562 | 390 | *((u8 *)req->buf+1), *((u8 *)req->buf+2)); |
c1dca562 DB |
391 | |
392 | /* Drop lock while we call out of driver; completions | |
393 | * could be issued while we do so. Disconnection may | |
394 | * happen too; maybe immediately before we queue this! | |
395 | * | |
396 | * NOTE that we may keep sending data for a while after | |
397 | * the TTY closed (dev->ioport->port_tty is NULL). | |
398 | */ | |
399 | spin_unlock(&port->port_lock); | |
400 | status = usb_ep_queue(in, req, GFP_ATOMIC); | |
401 | spin_lock(&port->port_lock); | |
402 | ||
403 | if (status) { | |
404 | pr_debug("%s: %s %s err %d\n", | |
405 | __func__, "queue", in->name, status); | |
406 | list_add(&req->list, pool); | |
407 | break; | |
408 | } | |
409 | ||
28609d40 JS |
410 | port->write_started++; |
411 | ||
c1dca562 DB |
412 | /* abort immediately after disconnect */ |
413 | if (!port->port_usb) | |
414 | break; | |
415 | } | |
416 | ||
35f95fd7 JS |
417 | if (do_tty_wake && port->port.tty) |
418 | tty_wakeup(port->port.tty); | |
c1dca562 DB |
419 | return status; |
420 | } | |
421 | ||
c1dca562 DB |
422 | /* |
423 | * Context: caller owns port_lock, and port_usb is set | |
424 | */ | |
425 | static unsigned gs_start_rx(struct gs_port *port) | |
426 | /* | |
427 | __releases(&port->port_lock) | |
428 | __acquires(&port->port_lock) | |
429 | */ | |
430 | { | |
431 | struct list_head *pool = &port->read_pool; | |
432 | struct usb_ep *out = port->port_usb->out; | |
c1dca562 DB |
433 | |
434 | while (!list_empty(pool)) { | |
435 | struct usb_request *req; | |
436 | int status; | |
437 | struct tty_struct *tty; | |
438 | ||
937ef73d | 439 | /* no more rx if closed */ |
35f95fd7 | 440 | tty = port->port.tty; |
937ef73d | 441 | if (!tty) |
c1dca562 DB |
442 | break; |
443 | ||
28609d40 JS |
444 | if (port->read_started >= QUEUE_SIZE) |
445 | break; | |
446 | ||
c1dca562 DB |
447 | req = list_entry(pool->next, struct usb_request, list); |
448 | list_del(&req->list); | |
449 | req->length = out->maxpacket; | |
450 | ||
451 | /* drop lock while we call out; the controller driver | |
452 | * may need to call us back (e.g. for disconnect) | |
453 | */ | |
454 | spin_unlock(&port->port_lock); | |
455 | status = usb_ep_queue(out, req, GFP_ATOMIC); | |
456 | spin_lock(&port->port_lock); | |
457 | ||
458 | if (status) { | |
459 | pr_debug("%s: %s %s err %d\n", | |
460 | __func__, "queue", out->name, status); | |
461 | list_add(&req->list, pool); | |
462 | break; | |
463 | } | |
28609d40 | 464 | port->read_started++; |
c1dca562 DB |
465 | |
466 | /* abort immediately after disconnect */ | |
467 | if (!port->port_usb) | |
468 | break; | |
469 | } | |
28609d40 | 470 | return port->read_started; |
c1dca562 DB |
471 | } |
472 | ||
937ef73d DB |
473 | /* |
474 | * RX tasklet takes data out of the RX queue and hands it up to the TTY | |
475 | * layer until it refuses to take any more data (or is throttled back). | |
476 | * Then it issues reads for any further data. | |
477 | * | |
478 | * If the RX queue becomes full enough that no usb_request is queued, | |
479 | * the OUT endpoint may begin NAKing as soon as its FIFO fills up. | |
480 | * So QUEUE_SIZE packets plus however many the FIFO holds (usually two) | |
481 | * can be buffered before the TTY layer's buffers (currently 64 KB). | |
482 | */ | |
483 | static void gs_rx_push(unsigned long _port) | |
c1dca562 | 484 | { |
937ef73d DB |
485 | struct gs_port *port = (void *)_port; |
486 | struct tty_struct *tty; | |
487 | struct list_head *queue = &port->read_queue; | |
488 | bool disconnect = false; | |
489 | bool do_push = false; | |
c1dca562 | 490 | |
937ef73d DB |
491 | /* hand any queued data to the tty */ |
492 | spin_lock_irq(&port->port_lock); | |
35f95fd7 | 493 | tty = port->port.tty; |
937ef73d DB |
494 | while (!list_empty(queue)) { |
495 | struct usb_request *req; | |
c1dca562 | 496 | |
937ef73d | 497 | req = list_first_entry(queue, struct usb_request, list); |
c1dca562 | 498 | |
937ef73d | 499 | /* leave data queued if tty was rx throttled */ |
05c7cd39 | 500 | if (tty && test_bit(TTY_THROTTLED, &tty->flags)) |
937ef73d DB |
501 | break; |
502 | ||
503 | switch (req->status) { | |
504 | case -ESHUTDOWN: | |
505 | disconnect = true; | |
506 | pr_vdebug(PREFIX "%d: shutdown\n", port->port_num); | |
507 | break; | |
508 | ||
509 | default: | |
510 | /* presumably a transient fault */ | |
511 | pr_warning(PREFIX "%d: unexpected RX status %d\n", | |
512 | port->port_num, req->status); | |
513 | /* FALLTHROUGH */ | |
514 | case 0: | |
515 | /* normal completion */ | |
516 | break; | |
517 | } | |
518 | ||
519 | /* push data to (open) tty */ | |
520 | if (req->actual) { | |
521 | char *packet = req->buf; | |
522 | unsigned size = req->actual; | |
523 | unsigned n; | |
524 | int count; | |
525 | ||
526 | /* we may have pushed part of this packet already... */ | |
527 | n = port->n_read; | |
528 | if (n) { | |
529 | packet += n; | |
530 | size -= n; | |
531 | } | |
532 | ||
05c7cd39 JS |
533 | count = tty_insert_flip_string(&port->port, packet, |
534 | size); | |
937ef73d DB |
535 | if (count) |
536 | do_push = true; | |
537 | if (count != size) { | |
538 | /* stop pushing; TTY layer can't handle more */ | |
539 | port->n_read += count; | |
540 | pr_vdebug(PREFIX "%d: rx block %d/%d\n", | |
541 | port->port_num, | |
542 | count, req->actual); | |
543 | break; | |
544 | } | |
545 | port->n_read = 0; | |
546 | } | |
05c7cd39 | 547 | |
937ef73d | 548 | list_move(&req->list, &port->read_pool); |
28609d40 | 549 | port->read_started--; |
937ef73d DB |
550 | } |
551 | ||
44a0c019 JP |
552 | /* Push from tty to ldisc; without low_latency set this is handled by |
553 | * a workqueue, so we won't get callbacks and can hold port_lock | |
937ef73d | 554 | */ |
2e124b4a JS |
555 | if (do_push) |
556 | tty_flip_buffer_push(&port->port); | |
937ef73d DB |
557 | |
558 | ||
559 | /* We want our data queue to become empty ASAP, keeping data | |
560 | * in the tty and ldisc (not here). If we couldn't push any | |
561 | * this time around, there may be trouble unless there's an | |
562 | * implicit tty_unthrottle() call on its way... | |
563 | * | |
564 | * REVISIT we should probably add a timer to keep the tasklet | |
565 | * from starving ... but it's not clear that case ever happens. | |
566 | */ | |
567 | if (!list_empty(queue) && tty) { | |
568 | if (!test_bit(TTY_THROTTLED, &tty->flags)) { | |
569 | if (do_push) | |
570 | tasklet_schedule(&port->push); | |
571 | else | |
572 | pr_warning(PREFIX "%d: RX not scheduled?\n", | |
573 | port->port_num); | |
574 | } | |
575 | } | |
576 | ||
577 | /* If we're still connected, refill the USB RX queue. */ | |
578 | if (!disconnect && port->port_usb) | |
579 | gs_start_rx(port); | |
580 | ||
581 | spin_unlock_irq(&port->port_lock); | |
582 | } | |
583 | ||
584 | static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) | |
585 | { | |
586 | struct gs_port *port = ep->driver_data; | |
587 | ||
588 | /* Queue all received data until the tty layer is ready for it. */ | |
589 | spin_lock(&port->port_lock); | |
590 | list_add_tail(&req->list, &port->read_queue); | |
591 | tasklet_schedule(&port->push); | |
c1dca562 DB |
592 | spin_unlock(&port->port_lock); |
593 | } | |
594 | ||
595 | static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) | |
596 | { | |
597 | struct gs_port *port = ep->driver_data; | |
598 | ||
599 | spin_lock(&port->port_lock); | |
600 | list_add(&req->list, &port->write_pool); | |
28609d40 | 601 | port->write_started--; |
c1dca562 DB |
602 | |
603 | switch (req->status) { | |
604 | default: | |
605 | /* presumably a transient fault */ | |
606 | pr_warning("%s: unexpected %s status %d\n", | |
607 | __func__, ep->name, req->status); | |
608 | /* FALL THROUGH */ | |
609 | case 0: | |
610 | /* normal completion */ | |
611 | gs_start_tx(port); | |
612 | break; | |
613 | ||
614 | case -ESHUTDOWN: | |
615 | /* disconnect */ | |
616 | pr_vdebug("%s: %s shutdown\n", __func__, ep->name); | |
617 | break; | |
618 | } | |
619 | ||
620 | spin_unlock(&port->port_lock); | |
621 | } | |
622 | ||
28609d40 JS |
623 | static void gs_free_requests(struct usb_ep *ep, struct list_head *head, |
624 | int *allocated) | |
c1dca562 DB |
625 | { |
626 | struct usb_request *req; | |
627 | ||
628 | while (!list_empty(head)) { | |
629 | req = list_entry(head->next, struct usb_request, list); | |
630 | list_del(&req->list); | |
631 | gs_free_req(ep, req); | |
28609d40 JS |
632 | if (allocated) |
633 | (*allocated)--; | |
c1dca562 DB |
634 | } |
635 | } | |
636 | ||
637 | static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, | |
28609d40 JS |
638 | void (*fn)(struct usb_ep *, struct usb_request *), |
639 | int *allocated) | |
c1dca562 DB |
640 | { |
641 | int i; | |
642 | struct usb_request *req; | |
28609d40 | 643 | int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE; |
c1dca562 DB |
644 | |
645 | /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't | |
646 | * do quite that many this time, don't fail ... we just won't | |
647 | * be as speedy as we might otherwise be. | |
648 | */ | |
28609d40 | 649 | for (i = 0; i < n; i++) { |
c1dca562 DB |
650 | req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); |
651 | if (!req) | |
652 | return list_empty(head) ? -ENOMEM : 0; | |
653 | req->complete = fn; | |
654 | list_add_tail(&req->list, head); | |
28609d40 JS |
655 | if (allocated) |
656 | (*allocated)++; | |
c1dca562 DB |
657 | } |
658 | return 0; | |
659 | } | |
660 | ||
661 | /** | |
662 | * gs_start_io - start USB I/O streams | |
663 | * @dev: encapsulates endpoints to use | |
664 | * Context: holding port_lock; port_tty and port_usb are non-null | |
665 | * | |
666 | * We only start I/O when something is connected to both sides of | |
667 | * this port. If nothing is listening on the host side, we may | |
668 | * be pointlessly filling up our TX buffers and FIFO. | |
669 | */ | |
670 | static int gs_start_io(struct gs_port *port) | |
671 | { | |
672 | struct list_head *head = &port->read_pool; | |
673 | struct usb_ep *ep = port->port_usb->out; | |
674 | int status; | |
675 | unsigned started; | |
676 | ||
677 | /* Allocate RX and TX I/O buffers. We can't easily do this much | |
678 | * earlier (with GFP_KERNEL) because the requests are coupled to | |
679 | * endpoints, as are the packet sizes we'll be using. Different | |
680 | * configurations may use different endpoints with a given port; | |
681 | * and high speed vs full speed changes packet sizes too. | |
682 | */ | |
28609d40 JS |
683 | status = gs_alloc_requests(ep, head, gs_read_complete, |
684 | &port->read_allocated); | |
c1dca562 DB |
685 | if (status) |
686 | return status; | |
687 | ||
688 | status = gs_alloc_requests(port->port_usb->in, &port->write_pool, | |
28609d40 | 689 | gs_write_complete, &port->write_allocated); |
c1dca562 | 690 | if (status) { |
28609d40 | 691 | gs_free_requests(ep, head, &port->read_allocated); |
c1dca562 DB |
692 | return status; |
693 | } | |
694 | ||
695 | /* queue read requests */ | |
937ef73d | 696 | port->n_read = 0; |
c1dca562 DB |
697 | started = gs_start_rx(port); |
698 | ||
699 | /* unblock any pending writes into our circular buffer */ | |
700 | if (started) { | |
35f95fd7 | 701 | tty_wakeup(port->port.tty); |
c1dca562 | 702 | } else { |
28609d40 JS |
703 | gs_free_requests(ep, head, &port->read_allocated); |
704 | gs_free_requests(port->port_usb->in, &port->write_pool, | |
705 | &port->write_allocated); | |
937ef73d | 706 | status = -EIO; |
c1dca562 DB |
707 | } |
708 | ||
937ef73d | 709 | return status; |
c1dca562 DB |
710 | } |
711 | ||
712 | /*-------------------------------------------------------------------------*/ | |
713 | ||
714 | /* TTY Driver */ | |
715 | ||
716 | /* | |
717 | * gs_open sets up the link between a gs_port and its associated TTY. | |
718 | * That link is broken *only* by TTY close(), and all driver methods | |
719 | * know that. | |
720 | */ | |
721 | static int gs_open(struct tty_struct *tty, struct file *file) | |
722 | { | |
723 | int port_num = tty->index; | |
724 | struct gs_port *port; | |
725 | int status; | |
726 | ||
c1dca562 DB |
727 | do { |
728 | mutex_lock(&ports[port_num].lock); | |
729 | port = ports[port_num].port; | |
730 | if (!port) | |
731 | status = -ENODEV; | |
732 | else { | |
733 | spin_lock_irq(&port->port_lock); | |
734 | ||
735 | /* already open? Great. */ | |
266e37ef | 736 | if (port->port.count) { |
c1dca562 | 737 | status = 0; |
266e37ef | 738 | port->port.count++; |
c1dca562 DB |
739 | |
740 | /* currently opening/closing? wait ... */ | |
741 | } else if (port->openclose) { | |
742 | status = -EBUSY; | |
743 | ||
744 | /* ... else we do the work */ | |
745 | } else { | |
746 | status = -EAGAIN; | |
747 | port->openclose = true; | |
748 | } | |
749 | spin_unlock_irq(&port->port_lock); | |
750 | } | |
751 | mutex_unlock(&ports[port_num].lock); | |
752 | ||
753 | switch (status) { | |
754 | default: | |
755 | /* fully handled */ | |
756 | return status; | |
757 | case -EAGAIN: | |
758 | /* must do the work */ | |
759 | break; | |
760 | case -EBUSY: | |
761 | /* wait for EAGAIN task to finish */ | |
762 | msleep(1); | |
763 | /* REVISIT could have a waitchannel here, if | |
764 | * concurrent open performance is important | |
765 | */ | |
766 | break; | |
767 | } | |
768 | } while (status != -EAGAIN); | |
769 | ||
770 | /* Do the "real open" */ | |
771 | spin_lock_irq(&port->port_lock); | |
772 | ||
773 | /* allocate circular buffer on first open */ | |
774 | if (port->port_write_buf.buf_buf == NULL) { | |
775 | ||
776 | spin_unlock_irq(&port->port_lock); | |
777 | status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE); | |
778 | spin_lock_irq(&port->port_lock); | |
779 | ||
780 | if (status) { | |
781 | pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n", | |
782 | port->port_num, tty, file); | |
783 | port->openclose = false; | |
784 | goto exit_unlock_port; | |
785 | } | |
786 | } | |
787 | ||
788 | /* REVISIT if REMOVED (ports[].port NULL), abort the open | |
789 | * to let rmmod work faster (but this way isn't wrong). | |
790 | */ | |
791 | ||
792 | /* REVISIT maybe wait for "carrier detect" */ | |
793 | ||
794 | tty->driver_data = port; | |
35f95fd7 | 795 | port->port.tty = tty; |
c1dca562 | 796 | |
266e37ef | 797 | port->port.count = 1; |
c1dca562 DB |
798 | port->openclose = false; |
799 | ||
c1dca562 DB |
800 | /* if connected, start the I/O stream */ |
801 | if (port->port_usb) { | |
1f1ba11b DB |
802 | struct gserial *gser = port->port_usb; |
803 | ||
c1dca562 DB |
804 | pr_debug("gs_open: start ttyGS%d\n", port->port_num); |
805 | gs_start_io(port); | |
806 | ||
1f1ba11b DB |
807 | if (gser->connect) |
808 | gser->connect(gser); | |
c1dca562 DB |
809 | } |
810 | ||
811 | pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); | |
812 | ||
813 | status = 0; | |
814 | ||
815 | exit_unlock_port: | |
816 | spin_unlock_irq(&port->port_lock); | |
817 | return status; | |
818 | } | |
819 | ||
820 | static int gs_writes_finished(struct gs_port *p) | |
821 | { | |
822 | int cond; | |
823 | ||
824 | /* return true on disconnect or empty buffer */ | |
825 | spin_lock_irq(&p->port_lock); | |
826 | cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf); | |
827 | spin_unlock_irq(&p->port_lock); | |
828 | ||
829 | return cond; | |
830 | } | |
831 | ||
832 | static void gs_close(struct tty_struct *tty, struct file *file) | |
833 | { | |
834 | struct gs_port *port = tty->driver_data; | |
1f1ba11b | 835 | struct gserial *gser; |
c1dca562 DB |
836 | |
837 | spin_lock_irq(&port->port_lock); | |
838 | ||
266e37ef JS |
839 | if (port->port.count != 1) { |
840 | if (port->port.count == 0) | |
c1dca562 DB |
841 | WARN_ON(1); |
842 | else | |
266e37ef | 843 | --port->port.count; |
c1dca562 DB |
844 | goto exit; |
845 | } | |
846 | ||
847 | pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); | |
848 | ||
849 | /* mark port as closing but in use; we can drop port lock | |
850 | * and sleep if necessary | |
851 | */ | |
852 | port->openclose = true; | |
266e37ef | 853 | port->port.count = 0; |
c1dca562 | 854 | |
1f1ba11b DB |
855 | gser = port->port_usb; |
856 | if (gser && gser->disconnect) | |
857 | gser->disconnect(gser); | |
c1dca562 DB |
858 | |
859 | /* wait for circular write buffer to drain, disconnect, or at | |
860 | * most GS_CLOSE_TIMEOUT seconds; then discard the rest | |
861 | */ | |
1f1ba11b | 862 | if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) { |
c1dca562 DB |
863 | spin_unlock_irq(&port->port_lock); |
864 | wait_event_interruptible_timeout(port->drain_wait, | |
865 | gs_writes_finished(port), | |
866 | GS_CLOSE_TIMEOUT * HZ); | |
867 | spin_lock_irq(&port->port_lock); | |
1f1ba11b | 868 | gser = port->port_usb; |
c1dca562 DB |
869 | } |
870 | ||
871 | /* Iff we're disconnected, there can be no I/O in flight so it's | |
872 | * ok to free the circular buffer; else just scrub it. And don't | |
873 | * let the push tasklet fire again until we're re-opened. | |
874 | */ | |
1f1ba11b | 875 | if (gser == NULL) |
c1dca562 DB |
876 | gs_buf_free(&port->port_write_buf); |
877 | else | |
878 | gs_buf_clear(&port->port_write_buf); | |
879 | ||
c1dca562 | 880 | tty->driver_data = NULL; |
35f95fd7 | 881 | port->port.tty = NULL; |
c1dca562 DB |
882 | |
883 | port->openclose = false; | |
884 | ||
885 | pr_debug("gs_close: ttyGS%d (%p,%p) done!\n", | |
886 | port->port_num, tty, file); | |
887 | ||
484ca3a3 | 888 | wake_up(&port->port.close_wait); |
c1dca562 DB |
889 | exit: |
890 | spin_unlock_irq(&port->port_lock); | |
891 | } | |
892 | ||
893 | static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
894 | { | |
895 | struct gs_port *port = tty->driver_data; | |
896 | unsigned long flags; | |
897 | int status; | |
898 | ||
899 | pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n", | |
900 | port->port_num, tty, count); | |
901 | ||
902 | spin_lock_irqsave(&port->port_lock, flags); | |
903 | if (count) | |
904 | count = gs_buf_put(&port->port_write_buf, buf, count); | |
905 | /* treat count == 0 as flush_chars() */ | |
906 | if (port->port_usb) | |
907 | status = gs_start_tx(port); | |
908 | spin_unlock_irqrestore(&port->port_lock, flags); | |
909 | ||
910 | return count; | |
911 | } | |
912 | ||
913 | static int gs_put_char(struct tty_struct *tty, unsigned char ch) | |
914 | { | |
915 | struct gs_port *port = tty->driver_data; | |
916 | unsigned long flags; | |
917 | int status; | |
918 | ||
bfa346ad | 919 | pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %pf\n", |
c1dca562 DB |
920 | port->port_num, tty, ch, __builtin_return_address(0)); |
921 | ||
922 | spin_lock_irqsave(&port->port_lock, flags); | |
923 | status = gs_buf_put(&port->port_write_buf, &ch, 1); | |
924 | spin_unlock_irqrestore(&port->port_lock, flags); | |
925 | ||
926 | return status; | |
927 | } | |
928 | ||
929 | static void gs_flush_chars(struct tty_struct *tty) | |
930 | { | |
931 | struct gs_port *port = tty->driver_data; | |
932 | unsigned long flags; | |
933 | ||
934 | pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty); | |
935 | ||
936 | spin_lock_irqsave(&port->port_lock, flags); | |
937 | if (port->port_usb) | |
938 | gs_start_tx(port); | |
939 | spin_unlock_irqrestore(&port->port_lock, flags); | |
940 | } | |
941 | ||
942 | static int gs_write_room(struct tty_struct *tty) | |
943 | { | |
944 | struct gs_port *port = tty->driver_data; | |
945 | unsigned long flags; | |
946 | int room = 0; | |
947 | ||
948 | spin_lock_irqsave(&port->port_lock, flags); | |
949 | if (port->port_usb) | |
950 | room = gs_buf_space_avail(&port->port_write_buf); | |
951 | spin_unlock_irqrestore(&port->port_lock, flags); | |
952 | ||
953 | pr_vdebug("gs_write_room: (%d,%p) room=%d\n", | |
954 | port->port_num, tty, room); | |
955 | ||
956 | return room; | |
957 | } | |
958 | ||
959 | static int gs_chars_in_buffer(struct tty_struct *tty) | |
960 | { | |
961 | struct gs_port *port = tty->driver_data; | |
962 | unsigned long flags; | |
963 | int chars = 0; | |
964 | ||
965 | spin_lock_irqsave(&port->port_lock, flags); | |
966 | chars = gs_buf_data_avail(&port->port_write_buf); | |
967 | spin_unlock_irqrestore(&port->port_lock, flags); | |
968 | ||
969 | pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n", | |
970 | port->port_num, tty, chars); | |
971 | ||
972 | return chars; | |
973 | } | |
974 | ||
975 | /* undo side effects of setting TTY_THROTTLED */ | |
976 | static void gs_unthrottle(struct tty_struct *tty) | |
977 | { | |
978 | struct gs_port *port = tty->driver_data; | |
979 | unsigned long flags; | |
c1dca562 DB |
980 | |
981 | spin_lock_irqsave(&port->port_lock, flags); | |
937ef73d DB |
982 | if (port->port_usb) { |
983 | /* Kickstart read queue processing. We don't do xon/xoff, | |
984 | * rts/cts, or other handshaking with the host, but if the | |
985 | * read queue backs up enough we'll be NAKing OUT packets. | |
986 | */ | |
987 | tasklet_schedule(&port->push); | |
988 | pr_vdebug(PREFIX "%d: unthrottle\n", port->port_num); | |
989 | } | |
c1dca562 | 990 | spin_unlock_irqrestore(&port->port_lock, flags); |
c1dca562 DB |
991 | } |
992 | ||
1f1ba11b DB |
993 | static int gs_break_ctl(struct tty_struct *tty, int duration) |
994 | { | |
995 | struct gs_port *port = tty->driver_data; | |
996 | int status = 0; | |
997 | struct gserial *gser; | |
998 | ||
999 | pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n", | |
1000 | port->port_num, duration); | |
1001 | ||
1002 | spin_lock_irq(&port->port_lock); | |
1003 | gser = port->port_usb; | |
1004 | if (gser && gser->send_break) | |
1005 | status = gser->send_break(gser, duration); | |
1006 | spin_unlock_irq(&port->port_lock); | |
1007 | ||
1008 | return status; | |
1009 | } | |
1010 | ||
c1dca562 DB |
1011 | static const struct tty_operations gs_tty_ops = { |
1012 | .open = gs_open, | |
1013 | .close = gs_close, | |
1014 | .write = gs_write, | |
1015 | .put_char = gs_put_char, | |
1016 | .flush_chars = gs_flush_chars, | |
1017 | .write_room = gs_write_room, | |
1018 | .chars_in_buffer = gs_chars_in_buffer, | |
1019 | .unthrottle = gs_unthrottle, | |
1f1ba11b | 1020 | .break_ctl = gs_break_ctl, |
c1dca562 DB |
1021 | }; |
1022 | ||
1023 | /*-------------------------------------------------------------------------*/ | |
1024 | ||
1025 | static struct tty_driver *gs_tty_driver; | |
1026 | ||
c3c04b29 | 1027 | static int |
c1dca562 DB |
1028 | gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) |
1029 | { | |
1030 | struct gs_port *port; | |
19b10a88 SAS |
1031 | int ret = 0; |
1032 | ||
1033 | mutex_lock(&ports[port_num].lock); | |
1034 | if (ports[port_num].port) { | |
1035 | ret = -EBUSY; | |
1036 | goto out; | |
1037 | } | |
c1dca562 DB |
1038 | |
1039 | port = kzalloc(sizeof(struct gs_port), GFP_KERNEL); | |
19b10a88 SAS |
1040 | if (port == NULL) { |
1041 | ret = -ENOMEM; | |
1042 | goto out; | |
1043 | } | |
c1dca562 | 1044 | |
266e37ef | 1045 | tty_port_init(&port->port); |
c1dca562 | 1046 | spin_lock_init(&port->port_lock); |
c1dca562 DB |
1047 | init_waitqueue_head(&port->drain_wait); |
1048 | ||
1049 | tasklet_init(&port->push, gs_rx_push, (unsigned long) port); | |
1050 | ||
1051 | INIT_LIST_HEAD(&port->read_pool); | |
937ef73d | 1052 | INIT_LIST_HEAD(&port->read_queue); |
c1dca562 DB |
1053 | INIT_LIST_HEAD(&port->write_pool); |
1054 | ||
1055 | port->port_num = port_num; | |
1056 | port->port_line_coding = *coding; | |
1057 | ||
1058 | ports[port_num].port = port; | |
19b10a88 SAS |
1059 | out: |
1060 | mutex_unlock(&ports[port_num].lock); | |
1061 | return ret; | |
c1dca562 DB |
1062 | } |
1063 | ||
1064 | static int gs_closed(struct gs_port *port) | |
1065 | { | |
1066 | int cond; | |
1067 | ||
1068 | spin_lock_irq(&port->port_lock); | |
266e37ef | 1069 | cond = (port->port.count == 0) && !port->openclose; |
c1dca562 DB |
1070 | spin_unlock_irq(&port->port_lock); |
1071 | return cond; | |
1072 | } | |
1073 | ||
19b10a88 SAS |
1074 | static void gserial_free_port(struct gs_port *port) |
1075 | { | |
1076 | tasklet_kill(&port->push); | |
1077 | /* wait for old opens to finish */ | |
1078 | wait_event(port->port.close_wait, gs_closed(port)); | |
1079 | WARN_ON(port->port_usb != NULL); | |
1080 | tty_port_destroy(&port->port); | |
1081 | kfree(port); | |
1082 | } | |
1083 | ||
1084 | void gserial_free_line(unsigned char port_num) | |
c1dca562 | 1085 | { |
c1dca562 DB |
1086 | struct gs_port *port; |
1087 | ||
19b10a88 SAS |
1088 | mutex_lock(&ports[port_num].lock); |
1089 | if (WARN_ON(!ports[port_num].port)) { | |
1090 | mutex_unlock(&ports[port_num].lock); | |
ac90e365 | 1091 | return; |
19b10a88 SAS |
1092 | } |
1093 | port = ports[port_num].port; | |
1094 | ports[port_num].port = NULL; | |
1095 | mutex_unlock(&ports[port_num].lock); | |
ac90e365 | 1096 | |
19b10a88 SAS |
1097 | gserial_free_port(port); |
1098 | tty_unregister_device(gs_tty_driver, port_num); | |
1099 | } | |
1100 | EXPORT_SYMBOL_GPL(gserial_free_line); | |
937ef73d | 1101 | |
19b10a88 SAS |
1102 | int gserial_alloc_line(unsigned char *line_num) |
1103 | { | |
1104 | struct usb_cdc_line_coding coding; | |
1105 | struct device *tty_dev; | |
1106 | int ret; | |
1107 | int port_num; | |
c1dca562 | 1108 | |
19b10a88 SAS |
1109 | coding.dwDTERate = cpu_to_le32(9600); |
1110 | coding.bCharFormat = 8; | |
1111 | coding.bParityType = USB_CDC_NO_PARITY; | |
1112 | coding.bDataBits = USB_CDC_1_STOP_BITS; | |
c1dca562 | 1113 | |
19b10a88 SAS |
1114 | for (port_num = 0; port_num < MAX_U_SERIAL_PORTS; port_num++) { |
1115 | ret = gs_port_alloc(port_num, &coding); | |
1116 | if (ret == -EBUSY) | |
1117 | continue; | |
1118 | if (ret) | |
1119 | return ret; | |
1120 | break; | |
c1dca562 | 1121 | } |
19b10a88 SAS |
1122 | if (ret) |
1123 | return ret; | |
c1dca562 | 1124 | |
19b10a88 | 1125 | /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */ |
c1dca562 | 1126 | |
19b10a88 SAS |
1127 | tty_dev = tty_port_register_device(&ports[port_num].port->port, |
1128 | gs_tty_driver, port_num, NULL); | |
1129 | if (IS_ERR(tty_dev)) { | |
1130 | struct gs_port *port; | |
1131 | pr_err("%s: failed to register tty for port %d, err %ld\n", | |
1132 | __func__, port_num, PTR_ERR(tty_dev)); | |
c1dca562 | 1133 | |
19b10a88 SAS |
1134 | ret = PTR_ERR(tty_dev); |
1135 | port = ports[port_num].port; | |
1136 | ports[port_num].port = NULL; | |
1137 | gserial_free_port(port); | |
1138 | goto err; | |
1139 | } | |
1140 | *line_num = port_num; | |
1141 | err: | |
1142 | return ret; | |
c1dca562 | 1143 | } |
19b10a88 | 1144 | EXPORT_SYMBOL_GPL(gserial_alloc_line); |
c1dca562 DB |
1145 | |
1146 | /** | |
1147 | * gserial_connect - notify TTY I/O glue that USB link is active | |
1148 | * @gser: the function, set up with endpoints and descriptors | |
1149 | * @port_num: which port is active | |
1150 | * Context: any (usually from irq) | |
1151 | * | |
1152 | * This is called activate endpoints and let the TTY layer know that | |
1153 | * the connection is active ... not unlike "carrier detect". It won't | |
1154 | * necessarily start I/O queues; unless the TTY is held open by any | |
1155 | * task, there would be no point. However, the endpoints will be | |
1156 | * activated so the USB host can perform I/O, subject to basic USB | |
1157 | * hardware flow control. | |
1158 | * | |
1159 | * Caller needs to have set up the endpoints and USB function in @dev | |
1160 | * before calling this, as well as the appropriate (speed-specific) | |
19b10a88 SAS |
1161 | * endpoint descriptors, and also have allocate @port_num by calling |
1162 | * @gserial_alloc_line(). | |
c1dca562 DB |
1163 | * |
1164 | * Returns negative errno or zero. | |
1165 | * On success, ep->driver_data will be overwritten. | |
1166 | */ | |
1167 | int gserial_connect(struct gserial *gser, u8 port_num) | |
1168 | { | |
1169 | struct gs_port *port; | |
1170 | unsigned long flags; | |
1171 | int status; | |
1172 | ||
19b10a88 | 1173 | if (port_num >= MAX_U_SERIAL_PORTS) |
c1dca562 DB |
1174 | return -ENXIO; |
1175 | ||
c1dca562 | 1176 | port = ports[port_num].port; |
19b10a88 SAS |
1177 | if (!port) { |
1178 | pr_err("serial line %d not allocated.\n", port_num); | |
1179 | return -EINVAL; | |
1180 | } | |
1181 | if (port->port_usb) { | |
1182 | pr_err("serial line %d is in use.\n", port_num); | |
1183 | return -EBUSY; | |
1184 | } | |
c1dca562 DB |
1185 | |
1186 | /* activate the endpoints */ | |
72c973dd | 1187 | status = usb_ep_enable(gser->in); |
c1dca562 DB |
1188 | if (status < 0) |
1189 | return status; | |
1190 | gser->in->driver_data = port; | |
1191 | ||
72c973dd | 1192 | status = usb_ep_enable(gser->out); |
c1dca562 DB |
1193 | if (status < 0) |
1194 | goto fail_out; | |
1195 | gser->out->driver_data = port; | |
1196 | ||
1197 | /* then tell the tty glue that I/O can work */ | |
1198 | spin_lock_irqsave(&port->port_lock, flags); | |
1199 | gser->ioport = port; | |
1200 | port->port_usb = gser; | |
1201 | ||
1202 | /* REVISIT unclear how best to handle this state... | |
1203 | * we don't really couple it with the Linux TTY. | |
1204 | */ | |
1205 | gser->port_line_coding = port->port_line_coding; | |
1206 | ||
1207 | /* REVISIT if waiting on "carrier detect", signal. */ | |
1208 | ||
1f1ba11b DB |
1209 | /* if it's already open, start I/O ... and notify the serial |
1210 | * protocol about open/close status (connect/disconnect). | |
c1dca562 | 1211 | */ |
266e37ef | 1212 | if (port->port.count) { |
c1dca562 DB |
1213 | pr_debug("gserial_connect: start ttyGS%d\n", port->port_num); |
1214 | gs_start_io(port); | |
1f1ba11b DB |
1215 | if (gser->connect) |
1216 | gser->connect(gser); | |
1217 | } else { | |
1218 | if (gser->disconnect) | |
1219 | gser->disconnect(gser); | |
c1dca562 DB |
1220 | } |
1221 | ||
1222 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1223 | ||
1224 | return status; | |
1225 | ||
1226 | fail_out: | |
1227 | usb_ep_disable(gser->in); | |
1228 | gser->in->driver_data = NULL; | |
1229 | return status; | |
1230 | } | |
3249ca22 | 1231 | EXPORT_SYMBOL_GPL(gserial_connect); |
c1dca562 DB |
1232 | /** |
1233 | * gserial_disconnect - notify TTY I/O glue that USB link is inactive | |
1234 | * @gser: the function, on which gserial_connect() was called | |
1235 | * Context: any (usually from irq) | |
1236 | * | |
1237 | * This is called to deactivate endpoints and let the TTY layer know | |
1238 | * that the connection went inactive ... not unlike "hangup". | |
1239 | * | |
1240 | * On return, the state is as if gserial_connect() had never been called; | |
1241 | * there is no active USB I/O on these endpoints. | |
1242 | */ | |
1243 | void gserial_disconnect(struct gserial *gser) | |
1244 | { | |
1245 | struct gs_port *port = gser->ioport; | |
1246 | unsigned long flags; | |
1247 | ||
1248 | if (!port) | |
1249 | return; | |
1250 | ||
1251 | /* tell the TTY glue not to do I/O here any more */ | |
1252 | spin_lock_irqsave(&port->port_lock, flags); | |
1253 | ||
1254 | /* REVISIT as above: how best to track this? */ | |
1255 | port->port_line_coding = gser->port_line_coding; | |
1256 | ||
1257 | port->port_usb = NULL; | |
1258 | gser->ioport = NULL; | |
266e37ef | 1259 | if (port->port.count > 0 || port->openclose) { |
c1dca562 | 1260 | wake_up_interruptible(&port->drain_wait); |
35f95fd7 JS |
1261 | if (port->port.tty) |
1262 | tty_hangup(port->port.tty); | |
c1dca562 DB |
1263 | } |
1264 | spin_unlock_irqrestore(&port->port_lock, flags); | |
1265 | ||
1266 | /* disable endpoints, aborting down any active I/O */ | |
1267 | usb_ep_disable(gser->out); | |
1268 | gser->out->driver_data = NULL; | |
1269 | ||
1270 | usb_ep_disable(gser->in); | |
1271 | gser->in->driver_data = NULL; | |
1272 | ||
1273 | /* finally, free any unused/unusable I/O buffers */ | |
1274 | spin_lock_irqsave(&port->port_lock, flags); | |
266e37ef | 1275 | if (port->port.count == 0 && !port->openclose) |
c1dca562 | 1276 | gs_buf_free(&port->port_write_buf); |
28609d40 JS |
1277 | gs_free_requests(gser->out, &port->read_pool, NULL); |
1278 | gs_free_requests(gser->out, &port->read_queue, NULL); | |
1279 | gs_free_requests(gser->in, &port->write_pool, NULL); | |
1280 | ||
1281 | port->read_allocated = port->read_started = | |
1282 | port->write_allocated = port->write_started = 0; | |
1283 | ||
c1dca562 DB |
1284 | spin_unlock_irqrestore(&port->port_lock, flags); |
1285 | } | |
3249ca22 SAS |
1286 | EXPORT_SYMBOL_GPL(gserial_disconnect); |
1287 | ||
38b3ad56 | 1288 | static int userial_init(void) |
19b10a88 SAS |
1289 | { |
1290 | unsigned i; | |
1291 | int status; | |
1292 | ||
1293 | gs_tty_driver = alloc_tty_driver(MAX_U_SERIAL_PORTS); | |
1294 | if (!gs_tty_driver) | |
1295 | return -ENOMEM; | |
1296 | ||
1297 | gs_tty_driver->driver_name = "g_serial"; | |
1298 | gs_tty_driver->name = PREFIX; | |
1299 | /* uses dynamically assigned dev_t values */ | |
1300 | ||
1301 | gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
1302 | gs_tty_driver->subtype = SERIAL_TYPE_NORMAL; | |
1303 | gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; | |
1304 | gs_tty_driver->init_termios = tty_std_termios; | |
1305 | ||
1306 | /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on | |
1307 | * MS-Windows. Otherwise, most of these flags shouldn't affect | |
1308 | * anything unless we were to actually hook up to a serial line. | |
1309 | */ | |
1310 | gs_tty_driver->init_termios.c_cflag = | |
1311 | B9600 | CS8 | CREAD | HUPCL | CLOCAL; | |
1312 | gs_tty_driver->init_termios.c_ispeed = 9600; | |
1313 | gs_tty_driver->init_termios.c_ospeed = 9600; | |
1314 | ||
1315 | tty_set_operations(gs_tty_driver, &gs_tty_ops); | |
1316 | for (i = 0; i < MAX_U_SERIAL_PORTS; i++) | |
1317 | mutex_init(&ports[i].lock); | |
1318 | ||
1319 | /* export the driver ... */ | |
1320 | status = tty_register_driver(gs_tty_driver); | |
1321 | if (status) { | |
1322 | pr_err("%s: cannot register, err %d\n", | |
1323 | __func__, status); | |
1324 | goto fail; | |
1325 | } | |
1326 | ||
1327 | pr_debug("%s: registered %d ttyGS* device%s\n", __func__, | |
1328 | MAX_U_SERIAL_PORTS, | |
1329 | (MAX_U_SERIAL_PORTS == 1) ? "" : "s"); | |
1330 | ||
1331 | return status; | |
1332 | fail: | |
1333 | put_tty_driver(gs_tty_driver); | |
1334 | gs_tty_driver = NULL; | |
1335 | return status; | |
1336 | } | |
1337 | module_init(userial_init); | |
1338 | ||
1339 | static void userial_cleanup(void) | |
1340 | { | |
1341 | tty_unregister_driver(gs_tty_driver); | |
1342 | put_tty_driver(gs_tty_driver); | |
1343 | gs_tty_driver = NULL; | |
1344 | } | |
1345 | module_exit(userial_cleanup); | |
1346 | ||
3249ca22 | 1347 | MODULE_LICENSE("GPL"); |