Sebastian Andrzej Siewior | e220ff7 | 2012-09-06 20:11:06 +0200 | [diff] [blame] | 1 | /* |
| 2 | * u_serial.c - utilities for USB gadget "serial port"/TTY support |
| 3 | * |
| 4 | * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com) |
| 5 | * Copyright (C) 2008 David Brownell |
| 6 | * Copyright (C) 2008 by Nokia Corporation |
| 7 | * |
| 8 | * This code also borrows from usbserial.c, which is |
| 9 | * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com) |
| 10 | * Copyright (C) 2000 Peter Berger (pberger@brimson.com) |
| 11 | * Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com) |
| 12 | * |
| 13 | * This software is distributed under the terms of the GNU General |
| 14 | * Public License ("GPL") as published by the Free Software Foundation, |
| 15 | * either version 2 of that License or (at your option) any later version. |
| 16 | */ |
| 17 | |
| 18 | /* #define VERBOSE_DEBUG */ |
| 19 | |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/sched.h> |
| 22 | #include <linux/interrupt.h> |
| 23 | #include <linux/device.h> |
| 24 | #include <linux/delay.h> |
| 25 | #include <linux/tty.h> |
| 26 | #include <linux/tty_flip.h> |
| 27 | #include <linux/slab.h> |
| 28 | #include <linux/export.h> |
| 29 | |
| 30 | #include "u_serial.h" |
| 31 | |
| 32 | |
| 33 | /* |
| 34 | * This component encapsulates the TTY layer glue needed to provide basic |
| 35 | * "serial port" functionality through the USB gadget stack. Each such |
| 36 | * port is exposed through a /dev/ttyGS* node. |
| 37 | * |
| 38 | * After initialization (gserial_setup), these TTY port devices stay |
| 39 | * available until they are removed (gserial_cleanup). Each one may be |
| 40 | * connected to a USB function (gserial_connect), or disconnected (with |
| 41 | * gserial_disconnect) when the USB host issues a config change event. |
| 42 | * Data can only flow when the port is connected to the host. |
| 43 | * |
| 44 | * A given TTY port can be made available in multiple configurations. |
| 45 | * For example, each one might expose a ttyGS0 node which provides a |
| 46 | * login application. In one case that might use CDC ACM interface 0, |
| 47 | * while another configuration might use interface 3 for that. The |
| 48 | * work to handle that (including descriptor management) is not part |
| 49 | * of this component. |
| 50 | * |
| 51 | * Configurations may expose more than one TTY port. For example, if |
| 52 | * ttyGS0 provides login service, then ttyGS1 might provide dialer access |
| 53 | * for a telephone or fax link. And ttyGS2 might be something that just |
| 54 | * needs a simple byte stream interface for some messaging protocol that |
| 55 | * is managed in userspace ... OBEX, PTP, and MTP have been mentioned. |
| 56 | */ |
| 57 | |
| 58 | #define PREFIX "ttyGS" |
| 59 | |
| 60 | /* |
| 61 | * gserial is the lifecycle interface, used by USB functions |
| 62 | * gs_port is the I/O nexus, used by the tty driver |
| 63 | * tty_struct links to the tty/filesystem framework |
| 64 | * |
| 65 | * gserial <---> gs_port ... links will be null when the USB link is |
| 66 | * inactive; managed by gserial_{connect,disconnect}(). each gserial |
| 67 | * instance can wrap its own USB control protocol. |
| 68 | * gserial->ioport == usb_ep->driver_data ... gs_port |
| 69 | * gs_port->port_usb ... gserial |
| 70 | * |
| 71 | * gs_port <---> tty_struct ... links will be null when the TTY file |
| 72 | * isn't opened; managed by gs_open()/gs_close() |
| 73 | * gserial->port_tty ... tty_struct |
| 74 | * tty_struct->driver_data ... gserial |
| 75 | */ |
| 76 | |
| 77 | /* RX and TX queues can buffer QUEUE_SIZE packets before they hit the |
| 78 | * next layer of buffering. For TX that's a circular buffer; for RX |
| 79 | * consider it a NOP. A third layer is provided by the TTY code. |
| 80 | */ |
| 81 | #define QUEUE_SIZE 16 |
| 82 | #define WRITE_BUF_SIZE 8192 /* TX only */ |
| 83 | |
| 84 | /* circular buffer */ |
| 85 | struct gs_buf { |
| 86 | unsigned buf_size; |
| 87 | char *buf_buf; |
| 88 | char *buf_get; |
| 89 | char *buf_put; |
| 90 | }; |
| 91 | |
| 92 | /* |
| 93 | * The port structure holds info for each port, one for each minor number |
| 94 | * (and thus for each /dev/ node). |
| 95 | */ |
| 96 | struct gs_port { |
| 97 | struct tty_port port; |
| 98 | spinlock_t port_lock; /* guard port_* access */ |
| 99 | |
| 100 | struct gserial *port_usb; |
| 101 | |
| 102 | bool openclose; /* open/close in progress */ |
| 103 | u8 port_num; |
| 104 | |
| 105 | struct list_head read_pool; |
| 106 | int read_started; |
| 107 | int read_allocated; |
| 108 | struct list_head read_queue; |
| 109 | unsigned n_read; |
| 110 | struct tasklet_struct push; |
| 111 | |
| 112 | struct list_head write_pool; |
| 113 | int write_started; |
| 114 | int write_allocated; |
| 115 | struct gs_buf port_write_buf; |
| 116 | wait_queue_head_t drain_wait; /* wait while writes drain */ |
| 117 | |
| 118 | /* REVISIT this state ... */ |
| 119 | struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */ |
| 120 | }; |
| 121 | |
| 122 | /* increase N_PORTS if you need more */ |
| 123 | #define N_PORTS 4 |
| 124 | static struct portmaster { |
| 125 | struct mutex lock; /* protect open/close */ |
| 126 | struct gs_port *port; |
| 127 | } ports[N_PORTS]; |
| 128 | static unsigned n_ports; |
| 129 | |
| 130 | #define GS_CLOSE_TIMEOUT 15 /* seconds */ |
| 131 | |
| 132 | |
| 133 | |
| 134 | #ifdef VERBOSE_DEBUG |
| 135 | #define pr_vdebug(fmt, arg...) \ |
| 136 | pr_debug(fmt, ##arg) |
| 137 | #else |
| 138 | #define pr_vdebug(fmt, arg...) \ |
| 139 | ({ if (0) pr_debug(fmt, ##arg); }) |
| 140 | #endif |
| 141 | |
| 142 | /*-------------------------------------------------------------------------*/ |
| 143 | |
| 144 | /* Circular Buffer */ |
| 145 | |
| 146 | /* |
| 147 | * gs_buf_alloc |
| 148 | * |
| 149 | * Allocate a circular buffer and all associated memory. |
| 150 | */ |
| 151 | static int gs_buf_alloc(struct gs_buf *gb, unsigned size) |
| 152 | { |
| 153 | gb->buf_buf = kmalloc(size, GFP_KERNEL); |
| 154 | if (gb->buf_buf == NULL) |
| 155 | return -ENOMEM; |
| 156 | |
| 157 | gb->buf_size = size; |
| 158 | gb->buf_put = gb->buf_buf; |
| 159 | gb->buf_get = gb->buf_buf; |
| 160 | |
| 161 | return 0; |
| 162 | } |
| 163 | |
| 164 | /* |
| 165 | * gs_buf_free |
| 166 | * |
| 167 | * Free the buffer and all associated memory. |
| 168 | */ |
| 169 | static void gs_buf_free(struct gs_buf *gb) |
| 170 | { |
| 171 | kfree(gb->buf_buf); |
| 172 | gb->buf_buf = NULL; |
| 173 | } |
| 174 | |
| 175 | /* |
| 176 | * gs_buf_clear |
| 177 | * |
| 178 | * Clear out all data in the circular buffer. |
| 179 | */ |
| 180 | static void gs_buf_clear(struct gs_buf *gb) |
| 181 | { |
| 182 | gb->buf_get = gb->buf_put; |
| 183 | /* equivalent to a get of all data available */ |
| 184 | } |
| 185 | |
| 186 | /* |
| 187 | * gs_buf_data_avail |
| 188 | * |
| 189 | * Return the number of bytes of data written into the circular |
| 190 | * buffer. |
| 191 | */ |
| 192 | static unsigned gs_buf_data_avail(struct gs_buf *gb) |
| 193 | { |
| 194 | return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size; |
| 195 | } |
| 196 | |
| 197 | /* |
| 198 | * gs_buf_space_avail |
| 199 | * |
| 200 | * Return the number of bytes of space available in the circular |
| 201 | * buffer. |
| 202 | */ |
| 203 | static unsigned gs_buf_space_avail(struct gs_buf *gb) |
| 204 | { |
| 205 | return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size; |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * gs_buf_put |
| 210 | * |
| 211 | * Copy data data from a user buffer and put it into the circular buffer. |
| 212 | * Restrict to the amount of space available. |
| 213 | * |
| 214 | * Return the number of bytes copied. |
| 215 | */ |
| 216 | static unsigned |
| 217 | gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count) |
| 218 | { |
| 219 | unsigned len; |
| 220 | |
| 221 | len = gs_buf_space_avail(gb); |
| 222 | if (count > len) |
| 223 | count = len; |
| 224 | |
| 225 | if (count == 0) |
| 226 | return 0; |
| 227 | |
| 228 | len = gb->buf_buf + gb->buf_size - gb->buf_put; |
| 229 | if (count > len) { |
| 230 | memcpy(gb->buf_put, buf, len); |
| 231 | memcpy(gb->buf_buf, buf+len, count - len); |
| 232 | gb->buf_put = gb->buf_buf + count - len; |
| 233 | } else { |
| 234 | memcpy(gb->buf_put, buf, count); |
| 235 | if (count < len) |
| 236 | gb->buf_put += count; |
| 237 | else /* count == len */ |
| 238 | gb->buf_put = gb->buf_buf; |
| 239 | } |
| 240 | |
| 241 | return count; |
| 242 | } |
| 243 | |
| 244 | /* |
| 245 | * gs_buf_get |
| 246 | * |
| 247 | * Get data from the circular buffer and copy to the given buffer. |
| 248 | * Restrict to the amount of data available. |
| 249 | * |
| 250 | * Return the number of bytes copied. |
| 251 | */ |
| 252 | static unsigned |
| 253 | gs_buf_get(struct gs_buf *gb, char *buf, unsigned count) |
| 254 | { |
| 255 | unsigned len; |
| 256 | |
| 257 | len = gs_buf_data_avail(gb); |
| 258 | if (count > len) |
| 259 | count = len; |
| 260 | |
| 261 | if (count == 0) |
| 262 | return 0; |
| 263 | |
| 264 | len = gb->buf_buf + gb->buf_size - gb->buf_get; |
| 265 | if (count > len) { |
| 266 | memcpy(buf, gb->buf_get, len); |
| 267 | memcpy(buf+len, gb->buf_buf, count - len); |
| 268 | gb->buf_get = gb->buf_buf + count - len; |
| 269 | } else { |
| 270 | memcpy(buf, gb->buf_get, count); |
| 271 | if (count < len) |
| 272 | gb->buf_get += count; |
| 273 | else /* count == len */ |
| 274 | gb->buf_get = gb->buf_buf; |
| 275 | } |
| 276 | |
| 277 | return count; |
| 278 | } |
| 279 | |
| 280 | /*-------------------------------------------------------------------------*/ |
| 281 | |
| 282 | /* I/O glue between TTY (upper) and USB function (lower) driver layers */ |
| 283 | |
| 284 | /* |
| 285 | * gs_alloc_req |
| 286 | * |
| 287 | * Allocate a usb_request and its buffer. Returns a pointer to the |
| 288 | * usb_request or NULL if there is an error. |
| 289 | */ |
| 290 | struct usb_request * |
| 291 | gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) |
| 292 | { |
| 293 | struct usb_request *req; |
| 294 | |
| 295 | req = usb_ep_alloc_request(ep, kmalloc_flags); |
| 296 | |
| 297 | if (req != NULL) { |
| 298 | req->length = len; |
| 299 | req->buf = kmalloc(len, kmalloc_flags); |
| 300 | if (req->buf == NULL) { |
| 301 | usb_ep_free_request(ep, req); |
| 302 | return NULL; |
| 303 | } |
| 304 | } |
| 305 | |
| 306 | return req; |
| 307 | } |
| 308 | |
| 309 | /* |
| 310 | * gs_free_req |
| 311 | * |
| 312 | * Free a usb_request and its buffer. |
| 313 | */ |
| 314 | void gs_free_req(struct usb_ep *ep, struct usb_request *req) |
| 315 | { |
| 316 | kfree(req->buf); |
| 317 | usb_ep_free_request(ep, req); |
| 318 | } |
| 319 | |
| 320 | /* |
| 321 | * gs_send_packet |
| 322 | * |
| 323 | * If there is data to send, a packet is built in the given |
| 324 | * buffer and the size is returned. If there is no data to |
| 325 | * send, 0 is returned. |
| 326 | * |
| 327 | * Called with port_lock held. |
| 328 | */ |
| 329 | static unsigned |
| 330 | gs_send_packet(struct gs_port *port, char *packet, unsigned size) |
| 331 | { |
| 332 | unsigned len; |
| 333 | |
| 334 | len = gs_buf_data_avail(&port->port_write_buf); |
| 335 | if (len < size) |
| 336 | size = len; |
| 337 | if (size != 0) |
| 338 | size = gs_buf_get(&port->port_write_buf, packet, size); |
| 339 | return size; |
| 340 | } |
| 341 | |
| 342 | /* |
| 343 | * gs_start_tx |
| 344 | * |
| 345 | * This function finds available write requests, calls |
| 346 | * gs_send_packet to fill these packets with data, and |
| 347 | * continues until either there are no more write requests |
| 348 | * available or no more data to send. This function is |
| 349 | * run whenever data arrives or write requests are available. |
| 350 | * |
| 351 | * Context: caller owns port_lock; port_usb is non-null. |
| 352 | */ |
| 353 | static int gs_start_tx(struct gs_port *port) |
| 354 | /* |
| 355 | __releases(&port->port_lock) |
| 356 | __acquires(&port->port_lock) |
| 357 | */ |
| 358 | { |
| 359 | struct list_head *pool = &port->write_pool; |
| 360 | struct usb_ep *in = port->port_usb->in; |
| 361 | int status = 0; |
| 362 | bool do_tty_wake = false; |
| 363 | |
| 364 | while (!list_empty(pool)) { |
| 365 | struct usb_request *req; |
| 366 | int len; |
| 367 | |
| 368 | if (port->write_started >= QUEUE_SIZE) |
| 369 | break; |
| 370 | |
| 371 | req = list_entry(pool->next, struct usb_request, list); |
| 372 | len = gs_send_packet(port, req->buf, in->maxpacket); |
| 373 | if (len == 0) { |
| 374 | wake_up_interruptible(&port->drain_wait); |
| 375 | break; |
| 376 | } |
| 377 | do_tty_wake = true; |
| 378 | |
| 379 | req->length = len; |
| 380 | list_del(&req->list); |
| 381 | req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0); |
| 382 | |
| 383 | pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n", |
| 384 | port->port_num, len, *((u8 *)req->buf), |
| 385 | *((u8 *)req->buf+1), *((u8 *)req->buf+2)); |
| 386 | |
| 387 | /* Drop lock while we call out of driver; completions |
| 388 | * could be issued while we do so. Disconnection may |
| 389 | * happen too; maybe immediately before we queue this! |
| 390 | * |
| 391 | * NOTE that we may keep sending data for a while after |
| 392 | * the TTY closed (dev->ioport->port_tty is NULL). |
| 393 | */ |
| 394 | spin_unlock(&port->port_lock); |
| 395 | status = usb_ep_queue(in, req, GFP_ATOMIC); |
| 396 | spin_lock(&port->port_lock); |
| 397 | |
| 398 | if (status) { |
| 399 | pr_debug("%s: %s %s err %d\n", |
| 400 | __func__, "queue", in->name, status); |
| 401 | list_add(&req->list, pool); |
| 402 | break; |
| 403 | } |
| 404 | |
| 405 | port->write_started++; |
| 406 | |
| 407 | /* abort immediately after disconnect */ |
| 408 | if (!port->port_usb) |
| 409 | break; |
| 410 | } |
| 411 | |
| 412 | if (do_tty_wake && port->port.tty) |
| 413 | tty_wakeup(port->port.tty); |
| 414 | return status; |
| 415 | } |
| 416 | |
| 417 | /* |
| 418 | * Context: caller owns port_lock, and port_usb is set |
| 419 | */ |
| 420 | static unsigned gs_start_rx(struct gs_port *port) |
| 421 | /* |
| 422 | __releases(&port->port_lock) |
| 423 | __acquires(&port->port_lock) |
| 424 | */ |
| 425 | { |
| 426 | struct list_head *pool = &port->read_pool; |
| 427 | struct usb_ep *out = port->port_usb->out; |
| 428 | |
| 429 | while (!list_empty(pool)) { |
| 430 | struct usb_request *req; |
| 431 | int status; |
| 432 | struct tty_struct *tty; |
| 433 | |
| 434 | /* no more rx if closed */ |
| 435 | tty = port->port.tty; |
| 436 | if (!tty) |
| 437 | break; |
| 438 | |
| 439 | if (port->read_started >= QUEUE_SIZE) |
| 440 | break; |
| 441 | |
| 442 | req = list_entry(pool->next, struct usb_request, list); |
| 443 | list_del(&req->list); |
| 444 | req->length = out->maxpacket; |
| 445 | |
| 446 | /* drop lock while we call out; the controller driver |
| 447 | * may need to call us back (e.g. for disconnect) |
| 448 | */ |
| 449 | spin_unlock(&port->port_lock); |
| 450 | status = usb_ep_queue(out, req, GFP_ATOMIC); |
| 451 | spin_lock(&port->port_lock); |
| 452 | |
| 453 | if (status) { |
| 454 | pr_debug("%s: %s %s err %d\n", |
| 455 | __func__, "queue", out->name, status); |
| 456 | list_add(&req->list, pool); |
| 457 | break; |
| 458 | } |
| 459 | port->read_started++; |
| 460 | |
| 461 | /* abort immediately after disconnect */ |
| 462 | if (!port->port_usb) |
| 463 | break; |
| 464 | } |
| 465 | return port->read_started; |
| 466 | } |
| 467 | |
| 468 | /* |
| 469 | * RX tasklet takes data out of the RX queue and hands it up to the TTY |
| 470 | * layer until it refuses to take any more data (or is throttled back). |
| 471 | * Then it issues reads for any further data. |
| 472 | * |
| 473 | * If the RX queue becomes full enough that no usb_request is queued, |
| 474 | * the OUT endpoint may begin NAKing as soon as its FIFO fills up. |
| 475 | * So QUEUE_SIZE packets plus however many the FIFO holds (usually two) |
| 476 | * can be buffered before the TTY layer's buffers (currently 64 KB). |
| 477 | */ |
| 478 | static void gs_rx_push(unsigned long _port) |
| 479 | { |
| 480 | struct gs_port *port = (void *)_port; |
| 481 | struct tty_struct *tty; |
| 482 | struct list_head *queue = &port->read_queue; |
| 483 | bool disconnect = false; |
| 484 | bool do_push = false; |
| 485 | |
| 486 | /* hand any queued data to the tty */ |
| 487 | spin_lock_irq(&port->port_lock); |
| 488 | tty = port->port.tty; |
| 489 | while (!list_empty(queue)) { |
| 490 | struct usb_request *req; |
| 491 | |
| 492 | req = list_first_entry(queue, struct usb_request, list); |
| 493 | |
| 494 | /* discard data if tty was closed */ |
| 495 | if (!tty) |
| 496 | goto recycle; |
| 497 | |
| 498 | /* leave data queued if tty was rx throttled */ |
| 499 | if (test_bit(TTY_THROTTLED, &tty->flags)) |
| 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 | |
| 532 | count = tty_insert_flip_string(tty, packet, size); |
| 533 | if (count) |
| 534 | do_push = true; |
| 535 | if (count != size) { |
| 536 | /* stop pushing; TTY layer can't handle more */ |
| 537 | port->n_read += count; |
| 538 | pr_vdebug(PREFIX "%d: rx block %d/%d\n", |
| 539 | port->port_num, |
| 540 | count, req->actual); |
| 541 | break; |
| 542 | } |
| 543 | port->n_read = 0; |
| 544 | } |
| 545 | recycle: |
| 546 | list_move(&req->list, &port->read_pool); |
| 547 | port->read_started--; |
| 548 | } |
| 549 | |
| 550 | /* Push from tty to ldisc; without low_latency set this is handled by |
| 551 | * a workqueue, so we won't get callbacks and can hold port_lock |
| 552 | */ |
| 553 | if (tty && do_push) |
| 554 | tty_flip_buffer_push(tty); |
| 555 | |
| 556 | |
| 557 | /* We want our data queue to become empty ASAP, keeping data |
| 558 | * in the tty and ldisc (not here). If we couldn't push any |
| 559 | * this time around, there may be trouble unless there's an |
| 560 | * implicit tty_unthrottle() call on its way... |
| 561 | * |
| 562 | * REVISIT we should probably add a timer to keep the tasklet |
| 563 | * from starving ... but it's not clear that case ever happens. |
| 564 | */ |
| 565 | if (!list_empty(queue) && tty) { |
| 566 | if (!test_bit(TTY_THROTTLED, &tty->flags)) { |
| 567 | if (do_push) |
| 568 | tasklet_schedule(&port->push); |
| 569 | else |
| 570 | pr_warning(PREFIX "%d: RX not scheduled?\n", |
| 571 | port->port_num); |
| 572 | } |
| 573 | } |
| 574 | |
| 575 | /* If we're still connected, refill the USB RX queue. */ |
| 576 | if (!disconnect && port->port_usb) |
| 577 | gs_start_rx(port); |
| 578 | |
| 579 | spin_unlock_irq(&port->port_lock); |
| 580 | } |
| 581 | |
| 582 | static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) |
| 583 | { |
| 584 | struct gs_port *port = ep->driver_data; |
| 585 | |
| 586 | /* Queue all received data until the tty layer is ready for it. */ |
| 587 | spin_lock(&port->port_lock); |
| 588 | list_add_tail(&req->list, &port->read_queue); |
| 589 | tasklet_schedule(&port->push); |
| 590 | spin_unlock(&port->port_lock); |
| 591 | } |
| 592 | |
| 593 | static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) |
| 594 | { |
| 595 | struct gs_port *port = ep->driver_data; |
| 596 | |
| 597 | spin_lock(&port->port_lock); |
| 598 | list_add(&req->list, &port->write_pool); |
| 599 | port->write_started--; |
| 600 | |
| 601 | switch (req->status) { |
| 602 | default: |
| 603 | /* presumably a transient fault */ |
| 604 | pr_warning("%s: unexpected %s status %d\n", |
| 605 | __func__, ep->name, req->status); |
| 606 | /* FALL THROUGH */ |
| 607 | case 0: |
| 608 | /* normal completion */ |
| 609 | gs_start_tx(port); |
| 610 | break; |
| 611 | |
| 612 | case -ESHUTDOWN: |
| 613 | /* disconnect */ |
| 614 | pr_vdebug("%s: %s shutdown\n", __func__, ep->name); |
| 615 | break; |
| 616 | } |
| 617 | |
| 618 | spin_unlock(&port->port_lock); |
| 619 | } |
| 620 | |
| 621 | static void gs_free_requests(struct usb_ep *ep, struct list_head *head, |
| 622 | int *allocated) |
| 623 | { |
| 624 | struct usb_request *req; |
| 625 | |
| 626 | while (!list_empty(head)) { |
| 627 | req = list_entry(head->next, struct usb_request, list); |
| 628 | list_del(&req->list); |
| 629 | gs_free_req(ep, req); |
| 630 | if (allocated) |
| 631 | (*allocated)--; |
| 632 | } |
| 633 | } |
| 634 | |
| 635 | static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, |
| 636 | void (*fn)(struct usb_ep *, struct usb_request *), |
| 637 | int *allocated) |
| 638 | { |
| 639 | int i; |
| 640 | struct usb_request *req; |
| 641 | int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE; |
| 642 | |
| 643 | /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't |
| 644 | * do quite that many this time, don't fail ... we just won't |
| 645 | * be as speedy as we might otherwise be. |
| 646 | */ |
| 647 | for (i = 0; i < n; i++) { |
| 648 | req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); |
| 649 | if (!req) |
| 650 | return list_empty(head) ? -ENOMEM : 0; |
| 651 | req->complete = fn; |
| 652 | list_add_tail(&req->list, head); |
| 653 | if (allocated) |
| 654 | (*allocated)++; |
| 655 | } |
| 656 | return 0; |
| 657 | } |
| 658 | |
| 659 | /** |
| 660 | * gs_start_io - start USB I/O streams |
| 661 | * @dev: encapsulates endpoints to use |
| 662 | * Context: holding port_lock; port_tty and port_usb are non-null |
| 663 | * |
| 664 | * We only start I/O when something is connected to both sides of |
| 665 | * this port. If nothing is listening on the host side, we may |
| 666 | * be pointlessly filling up our TX buffers and FIFO. |
| 667 | */ |
| 668 | static int gs_start_io(struct gs_port *port) |
| 669 | { |
| 670 | struct list_head *head = &port->read_pool; |
| 671 | struct usb_ep *ep = port->port_usb->out; |
| 672 | int status; |
| 673 | unsigned started; |
| 674 | |
| 675 | /* Allocate RX and TX I/O buffers. We can't easily do this much |
| 676 | * earlier (with GFP_KERNEL) because the requests are coupled to |
| 677 | * endpoints, as are the packet sizes we'll be using. Different |
| 678 | * configurations may use different endpoints with a given port; |
| 679 | * and high speed vs full speed changes packet sizes too. |
| 680 | */ |
| 681 | status = gs_alloc_requests(ep, head, gs_read_complete, |
| 682 | &port->read_allocated); |
| 683 | if (status) |
| 684 | return status; |
| 685 | |
| 686 | status = gs_alloc_requests(port->port_usb->in, &port->write_pool, |
| 687 | gs_write_complete, &port->write_allocated); |
| 688 | if (status) { |
| 689 | gs_free_requests(ep, head, &port->read_allocated); |
| 690 | return status; |
| 691 | } |
| 692 | |
| 693 | /* queue read requests */ |
| 694 | port->n_read = 0; |
| 695 | started = gs_start_rx(port); |
| 696 | |
| 697 | /* unblock any pending writes into our circular buffer */ |
| 698 | if (started) { |
| 699 | tty_wakeup(port->port.tty); |
| 700 | } else { |
| 701 | gs_free_requests(ep, head, &port->read_allocated); |
| 702 | gs_free_requests(port->port_usb->in, &port->write_pool, |
| 703 | &port->write_allocated); |
| 704 | status = -EIO; |
| 705 | } |
| 706 | |
| 707 | return status; |
| 708 | } |
| 709 | |
| 710 | /*-------------------------------------------------------------------------*/ |
| 711 | |
| 712 | /* TTY Driver */ |
| 713 | |
| 714 | /* |
| 715 | * gs_open sets up the link between a gs_port and its associated TTY. |
| 716 | * That link is broken *only* by TTY close(), and all driver methods |
| 717 | * know that. |
| 718 | */ |
| 719 | static int gs_open(struct tty_struct *tty, struct file *file) |
| 720 | { |
| 721 | int port_num = tty->index; |
| 722 | struct gs_port *port; |
| 723 | int status; |
| 724 | |
| 725 | do { |
| 726 | mutex_lock(&ports[port_num].lock); |
| 727 | port = ports[port_num].port; |
| 728 | if (!port) |
| 729 | status = -ENODEV; |
| 730 | else { |
| 731 | spin_lock_irq(&port->port_lock); |
| 732 | |
| 733 | /* already open? Great. */ |
| 734 | if (port->port.count) { |
| 735 | status = 0; |
| 736 | port->port.count++; |
| 737 | |
| 738 | /* currently opening/closing? wait ... */ |
| 739 | } else if (port->openclose) { |
| 740 | status = -EBUSY; |
| 741 | |
| 742 | /* ... else we do the work */ |
| 743 | } else { |
| 744 | status = -EAGAIN; |
| 745 | port->openclose = true; |
| 746 | } |
| 747 | spin_unlock_irq(&port->port_lock); |
| 748 | } |
| 749 | mutex_unlock(&ports[port_num].lock); |
| 750 | |
| 751 | switch (status) { |
| 752 | default: |
| 753 | /* fully handled */ |
| 754 | return status; |
| 755 | case -EAGAIN: |
| 756 | /* must do the work */ |
| 757 | break; |
| 758 | case -EBUSY: |
| 759 | /* wait for EAGAIN task to finish */ |
| 760 | msleep(1); |
| 761 | /* REVISIT could have a waitchannel here, if |
| 762 | * concurrent open performance is important |
| 763 | */ |
| 764 | break; |
| 765 | } |
| 766 | } while (status != -EAGAIN); |
| 767 | |
| 768 | /* Do the "real open" */ |
| 769 | spin_lock_irq(&port->port_lock); |
| 770 | |
| 771 | /* allocate circular buffer on first open */ |
| 772 | if (port->port_write_buf.buf_buf == NULL) { |
| 773 | |
| 774 | spin_unlock_irq(&port->port_lock); |
| 775 | status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE); |
| 776 | spin_lock_irq(&port->port_lock); |
| 777 | |
| 778 | if (status) { |
| 779 | pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n", |
| 780 | port->port_num, tty, file); |
| 781 | port->openclose = false; |
| 782 | goto exit_unlock_port; |
| 783 | } |
| 784 | } |
| 785 | |
| 786 | /* REVISIT if REMOVED (ports[].port NULL), abort the open |
| 787 | * to let rmmod work faster (but this way isn't wrong). |
| 788 | */ |
| 789 | |
| 790 | /* REVISIT maybe wait for "carrier detect" */ |
| 791 | |
| 792 | tty->driver_data = port; |
| 793 | port->port.tty = tty; |
| 794 | |
| 795 | port->port.count = 1; |
| 796 | port->openclose = false; |
| 797 | |
| 798 | /* if connected, start the I/O stream */ |
| 799 | if (port->port_usb) { |
| 800 | struct gserial *gser = port->port_usb; |
| 801 | |
| 802 | pr_debug("gs_open: start ttyGS%d\n", port->port_num); |
| 803 | gs_start_io(port); |
| 804 | |
| 805 | if (gser->connect) |
| 806 | gser->connect(gser); |
| 807 | } |
| 808 | |
| 809 | pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); |
| 810 | |
| 811 | status = 0; |
| 812 | |
| 813 | exit_unlock_port: |
| 814 | spin_unlock_irq(&port->port_lock); |
| 815 | return status; |
| 816 | } |
| 817 | |
| 818 | static int gs_writes_finished(struct gs_port *p) |
| 819 | { |
| 820 | int cond; |
| 821 | |
| 822 | /* return true on disconnect or empty buffer */ |
| 823 | spin_lock_irq(&p->port_lock); |
| 824 | cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf); |
| 825 | spin_unlock_irq(&p->port_lock); |
| 826 | |
| 827 | return cond; |
| 828 | } |
| 829 | |
| 830 | static void gs_close(struct tty_struct *tty, struct file *file) |
| 831 | { |
| 832 | struct gs_port *port = tty->driver_data; |
| 833 | struct gserial *gser; |
| 834 | |
| 835 | spin_lock_irq(&port->port_lock); |
| 836 | |
| 837 | if (port->port.count != 1) { |
| 838 | if (port->port.count == 0) |
| 839 | WARN_ON(1); |
| 840 | else |
| 841 | --port->port.count; |
| 842 | goto exit; |
| 843 | } |
| 844 | |
| 845 | pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); |
| 846 | |
| 847 | /* mark port as closing but in use; we can drop port lock |
| 848 | * and sleep if necessary |
| 849 | */ |
| 850 | port->openclose = true; |
| 851 | port->port.count = 0; |
| 852 | |
| 853 | gser = port->port_usb; |
| 854 | if (gser && gser->disconnect) |
| 855 | gser->disconnect(gser); |
| 856 | |
| 857 | /* wait for circular write buffer to drain, disconnect, or at |
| 858 | * most GS_CLOSE_TIMEOUT seconds; then discard the rest |
| 859 | */ |
| 860 | if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) { |
| 861 | spin_unlock_irq(&port->port_lock); |
| 862 | wait_event_interruptible_timeout(port->drain_wait, |
| 863 | gs_writes_finished(port), |
| 864 | GS_CLOSE_TIMEOUT * HZ); |
| 865 | spin_lock_irq(&port->port_lock); |
| 866 | gser = port->port_usb; |
| 867 | } |
| 868 | |
| 869 | /* Iff we're disconnected, there can be no I/O in flight so it's |
| 870 | * ok to free the circular buffer; else just scrub it. And don't |
| 871 | * let the push tasklet fire again until we're re-opened. |
| 872 | */ |
| 873 | if (gser == NULL) |
| 874 | gs_buf_free(&port->port_write_buf); |
| 875 | else |
| 876 | gs_buf_clear(&port->port_write_buf); |
| 877 | |
| 878 | tty->driver_data = NULL; |
| 879 | port->port.tty = NULL; |
| 880 | |
| 881 | port->openclose = false; |
| 882 | |
| 883 | pr_debug("gs_close: ttyGS%d (%p,%p) done!\n", |
| 884 | port->port_num, tty, file); |
| 885 | |
| 886 | wake_up_interruptible(&port->port.close_wait); |
| 887 | exit: |
| 888 | spin_unlock_irq(&port->port_lock); |
| 889 | } |
| 890 | |
| 891 | static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count) |
| 892 | { |
| 893 | struct gs_port *port = tty->driver_data; |
| 894 | unsigned long flags; |
| 895 | int status; |
| 896 | |
| 897 | pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n", |
| 898 | port->port_num, tty, count); |
| 899 | |
| 900 | spin_lock_irqsave(&port->port_lock, flags); |
| 901 | if (count) |
| 902 | count = gs_buf_put(&port->port_write_buf, buf, count); |
| 903 | /* treat count == 0 as flush_chars() */ |
| 904 | if (port->port_usb) |
| 905 | status = gs_start_tx(port); |
| 906 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 907 | |
| 908 | return count; |
| 909 | } |
| 910 | |
| 911 | static int gs_put_char(struct tty_struct *tty, unsigned char ch) |
| 912 | { |
| 913 | struct gs_port *port = tty->driver_data; |
| 914 | unsigned long flags; |
| 915 | int status; |
| 916 | |
| 917 | pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %pf\n", |
| 918 | port->port_num, tty, ch, __builtin_return_address(0)); |
| 919 | |
| 920 | spin_lock_irqsave(&port->port_lock, flags); |
| 921 | status = gs_buf_put(&port->port_write_buf, &ch, 1); |
| 922 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 923 | |
| 924 | return status; |
| 925 | } |
| 926 | |
| 927 | static void gs_flush_chars(struct tty_struct *tty) |
| 928 | { |
| 929 | struct gs_port *port = tty->driver_data; |
| 930 | unsigned long flags; |
| 931 | |
| 932 | pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty); |
| 933 | |
| 934 | spin_lock_irqsave(&port->port_lock, flags); |
| 935 | if (port->port_usb) |
| 936 | gs_start_tx(port); |
| 937 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 938 | } |
| 939 | |
| 940 | static int gs_write_room(struct tty_struct *tty) |
| 941 | { |
| 942 | struct gs_port *port = tty->driver_data; |
| 943 | unsigned long flags; |
| 944 | int room = 0; |
| 945 | |
| 946 | spin_lock_irqsave(&port->port_lock, flags); |
| 947 | if (port->port_usb) |
| 948 | room = gs_buf_space_avail(&port->port_write_buf); |
| 949 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 950 | |
| 951 | pr_vdebug("gs_write_room: (%d,%p) room=%d\n", |
| 952 | port->port_num, tty, room); |
| 953 | |
| 954 | return room; |
| 955 | } |
| 956 | |
| 957 | static int gs_chars_in_buffer(struct tty_struct *tty) |
| 958 | { |
| 959 | struct gs_port *port = tty->driver_data; |
| 960 | unsigned long flags; |
| 961 | int chars = 0; |
| 962 | |
| 963 | spin_lock_irqsave(&port->port_lock, flags); |
| 964 | chars = gs_buf_data_avail(&port->port_write_buf); |
| 965 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 966 | |
| 967 | pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n", |
| 968 | port->port_num, tty, chars); |
| 969 | |
| 970 | return chars; |
| 971 | } |
| 972 | |
| 973 | /* undo side effects of setting TTY_THROTTLED */ |
| 974 | static void gs_unthrottle(struct tty_struct *tty) |
| 975 | { |
| 976 | struct gs_port *port = tty->driver_data; |
| 977 | unsigned long flags; |
| 978 | |
| 979 | spin_lock_irqsave(&port->port_lock, flags); |
| 980 | if (port->port_usb) { |
| 981 | /* Kickstart read queue processing. We don't do xon/xoff, |
| 982 | * rts/cts, or other handshaking with the host, but if the |
| 983 | * read queue backs up enough we'll be NAKing OUT packets. |
| 984 | */ |
| 985 | tasklet_schedule(&port->push); |
| 986 | pr_vdebug(PREFIX "%d: unthrottle\n", port->port_num); |
| 987 | } |
| 988 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 989 | } |
| 990 | |
| 991 | static int gs_break_ctl(struct tty_struct *tty, int duration) |
| 992 | { |
| 993 | struct gs_port *port = tty->driver_data; |
| 994 | int status = 0; |
| 995 | struct gserial *gser; |
| 996 | |
| 997 | pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n", |
| 998 | port->port_num, duration); |
| 999 | |
| 1000 | spin_lock_irq(&port->port_lock); |
| 1001 | gser = port->port_usb; |
| 1002 | if (gser && gser->send_break) |
| 1003 | status = gser->send_break(gser, duration); |
| 1004 | spin_unlock_irq(&port->port_lock); |
| 1005 | |
| 1006 | return status; |
| 1007 | } |
| 1008 | |
| 1009 | static const struct tty_operations gs_tty_ops = { |
| 1010 | .open = gs_open, |
| 1011 | .close = gs_close, |
| 1012 | .write = gs_write, |
| 1013 | .put_char = gs_put_char, |
| 1014 | .flush_chars = gs_flush_chars, |
| 1015 | .write_room = gs_write_room, |
| 1016 | .chars_in_buffer = gs_chars_in_buffer, |
| 1017 | .unthrottle = gs_unthrottle, |
| 1018 | .break_ctl = gs_break_ctl, |
| 1019 | }; |
| 1020 | |
| 1021 | /*-------------------------------------------------------------------------*/ |
| 1022 | |
| 1023 | static struct tty_driver *gs_tty_driver; |
| 1024 | |
| 1025 | static int |
| 1026 | gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) |
| 1027 | { |
| 1028 | struct gs_port *port; |
| 1029 | |
| 1030 | port = kzalloc(sizeof(struct gs_port), GFP_KERNEL); |
| 1031 | if (port == NULL) |
| 1032 | return -ENOMEM; |
| 1033 | |
| 1034 | tty_port_init(&port->port); |
| 1035 | spin_lock_init(&port->port_lock); |
| 1036 | init_waitqueue_head(&port->drain_wait); |
| 1037 | |
| 1038 | tasklet_init(&port->push, gs_rx_push, (unsigned long) port); |
| 1039 | |
| 1040 | INIT_LIST_HEAD(&port->read_pool); |
| 1041 | INIT_LIST_HEAD(&port->read_queue); |
| 1042 | INIT_LIST_HEAD(&port->write_pool); |
| 1043 | |
| 1044 | port->port_num = port_num; |
| 1045 | port->port_line_coding = *coding; |
| 1046 | |
| 1047 | ports[port_num].port = port; |
| 1048 | |
| 1049 | return 0; |
| 1050 | } |
| 1051 | |
| 1052 | /** |
| 1053 | * gserial_setup - initialize TTY driver for one or more ports |
| 1054 | * @g: gadget to associate with these ports |
| 1055 | * @count: how many ports to support |
| 1056 | * Context: may sleep |
| 1057 | * |
| 1058 | * The TTY stack needs to know in advance how many devices it should |
| 1059 | * plan to manage. Use this call to set up the ports you will be |
| 1060 | * exporting through USB. Later, connect them to functions based |
| 1061 | * on what configuration is activated by the USB host; and disconnect |
| 1062 | * them as appropriate. |
| 1063 | * |
| 1064 | * An example would be a two-configuration device in which both |
| 1065 | * configurations expose port 0, but through different functions. |
| 1066 | * One configuration could even expose port 1 while the other |
| 1067 | * one doesn't. |
| 1068 | * |
| 1069 | * Returns negative errno or zero. |
| 1070 | */ |
| 1071 | int gserial_setup(struct usb_gadget *g, unsigned count) |
| 1072 | { |
| 1073 | unsigned i; |
| 1074 | struct usb_cdc_line_coding coding; |
| 1075 | int status; |
| 1076 | |
| 1077 | if (count == 0 || count > N_PORTS) |
| 1078 | return -EINVAL; |
| 1079 | |
| 1080 | gs_tty_driver = alloc_tty_driver(count); |
| 1081 | if (!gs_tty_driver) |
| 1082 | return -ENOMEM; |
| 1083 | |
| 1084 | gs_tty_driver->driver_name = "g_serial"; |
| 1085 | gs_tty_driver->name = PREFIX; |
| 1086 | /* uses dynamically assigned dev_t values */ |
| 1087 | |
| 1088 | gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; |
| 1089 | gs_tty_driver->subtype = SERIAL_TYPE_NORMAL; |
| 1090 | gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; |
| 1091 | gs_tty_driver->init_termios = tty_std_termios; |
| 1092 | |
| 1093 | /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on |
| 1094 | * MS-Windows. Otherwise, most of these flags shouldn't affect |
| 1095 | * anything unless we were to actually hook up to a serial line. |
| 1096 | */ |
| 1097 | gs_tty_driver->init_termios.c_cflag = |
| 1098 | B9600 | CS8 | CREAD | HUPCL | CLOCAL; |
| 1099 | gs_tty_driver->init_termios.c_ispeed = 9600; |
| 1100 | gs_tty_driver->init_termios.c_ospeed = 9600; |
| 1101 | |
| 1102 | coding.dwDTERate = cpu_to_le32(9600); |
| 1103 | coding.bCharFormat = 8; |
| 1104 | coding.bParityType = USB_CDC_NO_PARITY; |
| 1105 | coding.bDataBits = USB_CDC_1_STOP_BITS; |
| 1106 | |
| 1107 | tty_set_operations(gs_tty_driver, &gs_tty_ops); |
| 1108 | |
| 1109 | /* make devices be openable */ |
| 1110 | for (i = 0; i < count; i++) { |
| 1111 | mutex_init(&ports[i].lock); |
| 1112 | status = gs_port_alloc(i, &coding); |
| 1113 | if (status) { |
| 1114 | count = i; |
| 1115 | goto fail; |
| 1116 | } |
| 1117 | } |
| 1118 | n_ports = count; |
| 1119 | |
| 1120 | /* export the driver ... */ |
| 1121 | status = tty_register_driver(gs_tty_driver); |
| 1122 | if (status) { |
| 1123 | pr_err("%s: cannot register, err %d\n", |
| 1124 | __func__, status); |
| 1125 | goto fail; |
| 1126 | } |
| 1127 | |
| 1128 | /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */ |
| 1129 | for (i = 0; i < count; i++) { |
| 1130 | struct device *tty_dev; |
| 1131 | |
| 1132 | tty_dev = tty_register_device(gs_tty_driver, i, &g->dev); |
| 1133 | if (IS_ERR(tty_dev)) |
| 1134 | pr_warning("%s: no classdev for port %d, err %ld\n", |
| 1135 | __func__, i, PTR_ERR(tty_dev)); |
| 1136 | } |
| 1137 | |
| 1138 | pr_debug("%s: registered %d ttyGS* device%s\n", __func__, |
| 1139 | count, (count == 1) ? "" : "s"); |
| 1140 | |
| 1141 | return status; |
| 1142 | fail: |
| 1143 | while (count--) |
| 1144 | kfree(ports[count].port); |
| 1145 | put_tty_driver(gs_tty_driver); |
| 1146 | gs_tty_driver = NULL; |
| 1147 | return status; |
| 1148 | } |
| 1149 | |
| 1150 | static int gs_closed(struct gs_port *port) |
| 1151 | { |
| 1152 | int cond; |
| 1153 | |
| 1154 | spin_lock_irq(&port->port_lock); |
| 1155 | cond = (port->port.count == 0) && !port->openclose; |
| 1156 | spin_unlock_irq(&port->port_lock); |
| 1157 | return cond; |
| 1158 | } |
| 1159 | |
| 1160 | /** |
| 1161 | * gserial_cleanup - remove TTY-over-USB driver and devices |
| 1162 | * Context: may sleep |
| 1163 | * |
| 1164 | * This is called to free all resources allocated by @gserial_setup(). |
| 1165 | * Accordingly, it may need to wait until some open /dev/ files have |
| 1166 | * closed. |
| 1167 | * |
| 1168 | * The caller must have issued @gserial_disconnect() for any ports |
| 1169 | * that had previously been connected, so that there is never any |
| 1170 | * I/O pending when it's called. |
| 1171 | */ |
| 1172 | void gserial_cleanup(void) |
| 1173 | { |
| 1174 | unsigned i; |
| 1175 | struct gs_port *port; |
| 1176 | |
| 1177 | if (!gs_tty_driver) |
| 1178 | return; |
| 1179 | |
| 1180 | /* start sysfs and /dev/ttyGS* node removal */ |
| 1181 | for (i = 0; i < n_ports; i++) |
| 1182 | tty_unregister_device(gs_tty_driver, i); |
| 1183 | |
| 1184 | for (i = 0; i < n_ports; i++) { |
| 1185 | /* prevent new opens */ |
| 1186 | mutex_lock(&ports[i].lock); |
| 1187 | port = ports[i].port; |
| 1188 | ports[i].port = NULL; |
| 1189 | mutex_unlock(&ports[i].lock); |
| 1190 | |
| 1191 | tasklet_kill(&port->push); |
| 1192 | |
| 1193 | /* wait for old opens to finish */ |
| 1194 | wait_event(port->port.close_wait, gs_closed(port)); |
| 1195 | |
| 1196 | WARN_ON(port->port_usb != NULL); |
| 1197 | |
| 1198 | kfree(port); |
| 1199 | } |
| 1200 | n_ports = 0; |
| 1201 | |
| 1202 | tty_unregister_driver(gs_tty_driver); |
| 1203 | put_tty_driver(gs_tty_driver); |
| 1204 | gs_tty_driver = NULL; |
| 1205 | |
| 1206 | pr_debug("%s: cleaned up ttyGS* support\n", __func__); |
| 1207 | } |
| 1208 | |
| 1209 | /** |
| 1210 | * gserial_connect - notify TTY I/O glue that USB link is active |
| 1211 | * @gser: the function, set up with endpoints and descriptors |
| 1212 | * @port_num: which port is active |
| 1213 | * Context: any (usually from irq) |
| 1214 | * |
| 1215 | * This is called activate endpoints and let the TTY layer know that |
| 1216 | * the connection is active ... not unlike "carrier detect". It won't |
| 1217 | * necessarily start I/O queues; unless the TTY is held open by any |
| 1218 | * task, there would be no point. However, the endpoints will be |
| 1219 | * activated so the USB host can perform I/O, subject to basic USB |
| 1220 | * hardware flow control. |
| 1221 | * |
| 1222 | * Caller needs to have set up the endpoints and USB function in @dev |
| 1223 | * before calling this, as well as the appropriate (speed-specific) |
| 1224 | * endpoint descriptors, and also have set up the TTY driver by calling |
| 1225 | * @gserial_setup(). |
| 1226 | * |
| 1227 | * Returns negative errno or zero. |
| 1228 | * On success, ep->driver_data will be overwritten. |
| 1229 | */ |
| 1230 | int gserial_connect(struct gserial *gser, u8 port_num) |
| 1231 | { |
| 1232 | struct gs_port *port; |
| 1233 | unsigned long flags; |
| 1234 | int status; |
| 1235 | |
| 1236 | if (!gs_tty_driver || port_num >= n_ports) |
| 1237 | return -ENXIO; |
| 1238 | |
| 1239 | /* we "know" gserial_cleanup() hasn't been called */ |
| 1240 | port = ports[port_num].port; |
| 1241 | |
| 1242 | /* activate the endpoints */ |
| 1243 | status = usb_ep_enable(gser->in); |
| 1244 | if (status < 0) |
| 1245 | return status; |
| 1246 | gser->in->driver_data = port; |
| 1247 | |
| 1248 | status = usb_ep_enable(gser->out); |
| 1249 | if (status < 0) |
| 1250 | goto fail_out; |
| 1251 | gser->out->driver_data = port; |
| 1252 | |
| 1253 | /* then tell the tty glue that I/O can work */ |
| 1254 | spin_lock_irqsave(&port->port_lock, flags); |
| 1255 | gser->ioport = port; |
| 1256 | port->port_usb = gser; |
| 1257 | |
| 1258 | /* REVISIT unclear how best to handle this state... |
| 1259 | * we don't really couple it with the Linux TTY. |
| 1260 | */ |
| 1261 | gser->port_line_coding = port->port_line_coding; |
| 1262 | |
| 1263 | /* REVISIT if waiting on "carrier detect", signal. */ |
| 1264 | |
| 1265 | /* if it's already open, start I/O ... and notify the serial |
| 1266 | * protocol about open/close status (connect/disconnect). |
| 1267 | */ |
| 1268 | if (port->port.count) { |
| 1269 | pr_debug("gserial_connect: start ttyGS%d\n", port->port_num); |
| 1270 | gs_start_io(port); |
| 1271 | if (gser->connect) |
| 1272 | gser->connect(gser); |
| 1273 | } else { |
| 1274 | if (gser->disconnect) |
| 1275 | gser->disconnect(gser); |
| 1276 | } |
| 1277 | |
| 1278 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 1279 | |
| 1280 | return status; |
| 1281 | |
| 1282 | fail_out: |
| 1283 | usb_ep_disable(gser->in); |
| 1284 | gser->in->driver_data = NULL; |
| 1285 | return status; |
| 1286 | } |
| 1287 | |
| 1288 | /** |
| 1289 | * gserial_disconnect - notify TTY I/O glue that USB link is inactive |
| 1290 | * @gser: the function, on which gserial_connect() was called |
| 1291 | * Context: any (usually from irq) |
| 1292 | * |
| 1293 | * This is called to deactivate endpoints and let the TTY layer know |
| 1294 | * that the connection went inactive ... not unlike "hangup". |
| 1295 | * |
| 1296 | * On return, the state is as if gserial_connect() had never been called; |
| 1297 | * there is no active USB I/O on these endpoints. |
| 1298 | */ |
| 1299 | void gserial_disconnect(struct gserial *gser) |
| 1300 | { |
| 1301 | struct gs_port *port = gser->ioport; |
| 1302 | unsigned long flags; |
| 1303 | |
| 1304 | if (!port) |
| 1305 | return; |
| 1306 | |
| 1307 | /* tell the TTY glue not to do I/O here any more */ |
| 1308 | spin_lock_irqsave(&port->port_lock, flags); |
| 1309 | |
| 1310 | /* REVISIT as above: how best to track this? */ |
| 1311 | port->port_line_coding = gser->port_line_coding; |
| 1312 | |
| 1313 | port->port_usb = NULL; |
| 1314 | gser->ioport = NULL; |
| 1315 | if (port->port.count > 0 || port->openclose) { |
| 1316 | wake_up_interruptible(&port->drain_wait); |
| 1317 | if (port->port.tty) |
| 1318 | tty_hangup(port->port.tty); |
| 1319 | } |
| 1320 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 1321 | |
| 1322 | /* disable endpoints, aborting down any active I/O */ |
| 1323 | usb_ep_disable(gser->out); |
| 1324 | gser->out->driver_data = NULL; |
| 1325 | |
| 1326 | usb_ep_disable(gser->in); |
| 1327 | gser->in->driver_data = NULL; |
| 1328 | |
| 1329 | /* finally, free any unused/unusable I/O buffers */ |
| 1330 | spin_lock_irqsave(&port->port_lock, flags); |
| 1331 | if (port->port.count == 0 && !port->openclose) |
| 1332 | gs_buf_free(&port->port_write_buf); |
| 1333 | gs_free_requests(gser->out, &port->read_pool, NULL); |
| 1334 | gs_free_requests(gser->out, &port->read_queue, NULL); |
| 1335 | gs_free_requests(gser->in, &port->write_pool, NULL); |
| 1336 | |
| 1337 | port->read_allocated = port->read_started = |
| 1338 | port->write_allocated = port->write_started = 0; |
| 1339 | |
| 1340 | spin_unlock_irqrestore(&port->port_lock, flags); |
| 1341 | } |