1 /* 2 * USB Serial Converter Generic functions 3 * 4 * Copyright (C) 2010 - 2013 Johan Hovold (jhovold@gmail.com) 5 * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com) 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License version 9 * 2 as published by the Free Software Foundation. 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/errno.h> 14 #include <linux/slab.h> 15 #include <linux/sysrq.h> 16 #include <linux/tty.h> 17 #include <linux/tty_flip.h> 18 #include <linux/module.h> 19 #include <linux/moduleparam.h> 20 #include <linux/usb.h> 21 #include <linux/usb/serial.h> 22 #include <linux/uaccess.h> 23 #include <linux/kfifo.h> 24 #include <linux/serial.h> 25 26 #ifdef CONFIG_USB_SERIAL_GENERIC 27 28 static __u16 vendor = 0x05f9; 29 static __u16 product = 0xffff; 30 31 module_param(vendor, ushort, 0); 32 MODULE_PARM_DESC(vendor, "User specified USB idVendor"); 33 34 module_param(product, ushort, 0); 35 MODULE_PARM_DESC(product, "User specified USB idProduct"); 36 37 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */ 38 39 struct usb_serial_driver usb_serial_generic_device = { 40 .driver = { 41 .owner = THIS_MODULE, 42 .name = "generic", 43 }, 44 .id_table = generic_device_ids, 45 .num_ports = 1, 46 .throttle = usb_serial_generic_throttle, 47 .unthrottle = usb_serial_generic_unthrottle, 48 .resume = usb_serial_generic_resume, 49 }; 50 51 static struct usb_serial_driver * const serial_drivers[] = { 52 &usb_serial_generic_device, NULL 53 }; 54 55 #endif 56 57 int usb_serial_generic_register(void) 58 { 59 int retval = 0; 60 61 #ifdef CONFIG_USB_SERIAL_GENERIC 62 generic_device_ids[0].idVendor = vendor; 63 generic_device_ids[0].idProduct = product; 64 generic_device_ids[0].match_flags = 65 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT; 66 67 retval = usb_serial_register_drivers(serial_drivers, 68 "usbserial_generic", generic_device_ids); 69 #endif 70 return retval; 71 } 72 73 void usb_serial_generic_deregister(void) 74 { 75 #ifdef CONFIG_USB_SERIAL_GENERIC 76 usb_serial_deregister_drivers(serial_drivers); 77 #endif 78 } 79 80 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port) 81 { 82 int result = 0; 83 unsigned long flags; 84 85 spin_lock_irqsave(&port->lock, flags); 86 port->throttled = 0; 87 port->throttle_req = 0; 88 spin_unlock_irqrestore(&port->lock, flags); 89 90 if (port->bulk_in_size) 91 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL); 92 93 return result; 94 } 95 EXPORT_SYMBOL_GPL(usb_serial_generic_open); 96 97 void usb_serial_generic_close(struct usb_serial_port *port) 98 { 99 unsigned long flags; 100 int i; 101 102 if (port->bulk_out_size) { 103 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) 104 usb_kill_urb(port->write_urbs[i]); 105 106 spin_lock_irqsave(&port->lock, flags); 107 kfifo_reset_out(&port->write_fifo); 108 spin_unlock_irqrestore(&port->lock, flags); 109 } 110 if (port->bulk_in_size) { 111 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) 112 usb_kill_urb(port->read_urbs[i]); 113 } 114 } 115 EXPORT_SYMBOL_GPL(usb_serial_generic_close); 116 117 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port, 118 void *dest, size_t size) 119 { 120 return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock); 121 } 122 123 /** 124 * usb_serial_generic_write_start - start writing buffered data 125 * @port: usb-serial port 126 * @mem_flags: flags to use for memory allocations 127 * 128 * Serialised using USB_SERIAL_WRITE_BUSY flag. 129 * 130 * Return: Zero on success or if busy, otherwise a negative errno value. 131 */ 132 int usb_serial_generic_write_start(struct usb_serial_port *port, 133 gfp_t mem_flags) 134 { 135 struct urb *urb; 136 int count, result; 137 unsigned long flags; 138 int i; 139 140 if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags)) 141 return 0; 142 retry: 143 spin_lock_irqsave(&port->lock, flags); 144 if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) { 145 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags); 146 spin_unlock_irqrestore(&port->lock, flags); 147 return 0; 148 } 149 i = (int)find_first_bit(&port->write_urbs_free, 150 ARRAY_SIZE(port->write_urbs)); 151 spin_unlock_irqrestore(&port->lock, flags); 152 153 urb = port->write_urbs[i]; 154 count = port->serial->type->prepare_write_buffer(port, 155 urb->transfer_buffer, 156 port->bulk_out_size); 157 urb->transfer_buffer_length = count; 158 usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer); 159 spin_lock_irqsave(&port->lock, flags); 160 port->tx_bytes += count; 161 spin_unlock_irqrestore(&port->lock, flags); 162 163 clear_bit(i, &port->write_urbs_free); 164 result = usb_submit_urb(urb, mem_flags); 165 if (result) { 166 dev_err_console(port, "%s - error submitting urb: %d\n", 167 __func__, result); 168 set_bit(i, &port->write_urbs_free); 169 spin_lock_irqsave(&port->lock, flags); 170 port->tx_bytes -= count; 171 spin_unlock_irqrestore(&port->lock, flags); 172 173 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags); 174 return result; 175 } 176 177 goto retry; /* try sending off another urb */ 178 } 179 EXPORT_SYMBOL_GPL(usb_serial_generic_write_start); 180 181 /** 182 * usb_serial_generic_write - generic write function 183 * @tty: tty for the port 184 * @port: usb-serial port 185 * @buf: data to write 186 * @count: number of bytes to write 187 * 188 * Return: The number of characters buffered, which may be anything from 189 * zero to @count, or a negative errno value. 190 */ 191 int usb_serial_generic_write(struct tty_struct *tty, 192 struct usb_serial_port *port, const unsigned char *buf, int count) 193 { 194 int result; 195 196 if (!port->bulk_out_size) 197 return -ENODEV; 198 199 if (!count) 200 return 0; 201 202 count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock); 203 result = usb_serial_generic_write_start(port, GFP_ATOMIC); 204 if (result) 205 return result; 206 207 return count; 208 } 209 EXPORT_SYMBOL_GPL(usb_serial_generic_write); 210 211 int usb_serial_generic_write_room(struct tty_struct *tty) 212 { 213 struct usb_serial_port *port = tty->driver_data; 214 unsigned long flags; 215 int room; 216 217 if (!port->bulk_out_size) 218 return 0; 219 220 spin_lock_irqsave(&port->lock, flags); 221 room = kfifo_avail(&port->write_fifo); 222 spin_unlock_irqrestore(&port->lock, flags); 223 224 dev_dbg(&port->dev, "%s - returns %d\n", __func__, room); 225 return room; 226 } 227 228 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty) 229 { 230 struct usb_serial_port *port = tty->driver_data; 231 unsigned long flags; 232 int chars; 233 234 if (!port->bulk_out_size) 235 return 0; 236 237 spin_lock_irqsave(&port->lock, flags); 238 chars = kfifo_len(&port->write_fifo) + port->tx_bytes; 239 spin_unlock_irqrestore(&port->lock, flags); 240 241 dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars); 242 return chars; 243 } 244 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer); 245 246 void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout) 247 { 248 struct usb_serial_port *port = tty->driver_data; 249 unsigned int bps; 250 unsigned long period; 251 unsigned long expire; 252 253 bps = tty_get_baud_rate(tty); 254 if (!bps) 255 bps = 9600; /* B0 */ 256 /* 257 * Use a poll-period of roughly the time it takes to send one 258 * character or at least one jiffy. 259 */ 260 period = max_t(unsigned long, (10 * HZ / bps), 1); 261 period = min_t(unsigned long, period, timeout); 262 263 dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n", 264 __func__, jiffies_to_msecs(timeout), 265 jiffies_to_msecs(period)); 266 expire = jiffies + timeout; 267 while (!port->serial->type->tx_empty(port)) { 268 schedule_timeout_interruptible(period); 269 if (signal_pending(current)) 270 break; 271 if (time_after(jiffies, expire)) 272 break; 273 } 274 } 275 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent); 276 277 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port, 278 int index, gfp_t mem_flags) 279 { 280 int res; 281 282 if (!test_and_clear_bit(index, &port->read_urbs_free)) 283 return 0; 284 285 dev_dbg(&port->dev, "%s - urb %d\n", __func__, index); 286 287 res = usb_submit_urb(port->read_urbs[index], mem_flags); 288 if (res) { 289 if (res != -EPERM) { 290 dev_err(&port->dev, 291 "%s - usb_submit_urb failed: %d\n", 292 __func__, res); 293 } 294 set_bit(index, &port->read_urbs_free); 295 return res; 296 } 297 298 return 0; 299 } 300 301 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port, 302 gfp_t mem_flags) 303 { 304 int res; 305 int i; 306 307 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) { 308 res = usb_serial_generic_submit_read_urb(port, i, mem_flags); 309 if (res) 310 goto err; 311 } 312 313 return 0; 314 err: 315 for (; i >= 0; --i) 316 usb_kill_urb(port->read_urbs[i]); 317 318 return res; 319 } 320 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs); 321 322 void usb_serial_generic_process_read_urb(struct urb *urb) 323 { 324 struct usb_serial_port *port = urb->context; 325 char *ch = (char *)urb->transfer_buffer; 326 int i; 327 328 if (!urb->actual_length) 329 return; 330 /* 331 * The per character mucking around with sysrq path it too slow for 332 * stuff like 3G modems, so shortcircuit it in the 99.9999999% of 333 * cases where the USB serial is not a console anyway. 334 */ 335 if (!port->port.console || !port->sysrq) 336 tty_insert_flip_string(&port->port, ch, urb->actual_length); 337 else { 338 for (i = 0; i < urb->actual_length; i++, ch++) { 339 if (!usb_serial_handle_sysrq_char(port, *ch)) 340 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL); 341 } 342 } 343 tty_flip_buffer_push(&port->port); 344 } 345 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb); 346 347 void usb_serial_generic_read_bulk_callback(struct urb *urb) 348 { 349 struct usb_serial_port *port = urb->context; 350 unsigned char *data = urb->transfer_buffer; 351 unsigned long flags; 352 int i; 353 354 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) { 355 if (urb == port->read_urbs[i]) 356 break; 357 } 358 set_bit(i, &port->read_urbs_free); 359 360 dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i, 361 urb->actual_length); 362 363 if (urb->status) { 364 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n", 365 __func__, urb->status); 366 return; 367 } 368 369 usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data); 370 port->serial->type->process_read_urb(urb); 371 372 /* Throttle the device if requested by tty */ 373 spin_lock_irqsave(&port->lock, flags); 374 port->throttled = port->throttle_req; 375 if (!port->throttled) { 376 spin_unlock_irqrestore(&port->lock, flags); 377 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC); 378 } else 379 spin_unlock_irqrestore(&port->lock, flags); 380 } 381 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback); 382 383 void usb_serial_generic_write_bulk_callback(struct urb *urb) 384 { 385 unsigned long flags; 386 struct usb_serial_port *port = urb->context; 387 int status = urb->status; 388 int i; 389 390 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) 391 if (port->write_urbs[i] == urb) 392 break; 393 394 spin_lock_irqsave(&port->lock, flags); 395 port->tx_bytes -= urb->transfer_buffer_length; 396 set_bit(i, &port->write_urbs_free); 397 spin_unlock_irqrestore(&port->lock, flags); 398 399 if (status) { 400 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n", 401 __func__, status); 402 403 spin_lock_irqsave(&port->lock, flags); 404 kfifo_reset_out(&port->write_fifo); 405 spin_unlock_irqrestore(&port->lock, flags); 406 } else { 407 usb_serial_generic_write_start(port, GFP_ATOMIC); 408 } 409 410 usb_serial_port_softint(port); 411 } 412 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback); 413 414 void usb_serial_generic_throttle(struct tty_struct *tty) 415 { 416 struct usb_serial_port *port = tty->driver_data; 417 unsigned long flags; 418 419 spin_lock_irqsave(&port->lock, flags); 420 port->throttle_req = 1; 421 spin_unlock_irqrestore(&port->lock, flags); 422 } 423 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle); 424 425 void usb_serial_generic_unthrottle(struct tty_struct *tty) 426 { 427 struct usb_serial_port *port = tty->driver_data; 428 int was_throttled; 429 430 spin_lock_irq(&port->lock); 431 was_throttled = port->throttled; 432 port->throttled = port->throttle_req = 0; 433 spin_unlock_irq(&port->lock); 434 435 if (was_throttled) 436 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL); 437 } 438 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle); 439 440 static bool usb_serial_generic_msr_changed(struct tty_struct *tty, 441 unsigned long arg, struct async_icount *cprev) 442 { 443 struct usb_serial_port *port = tty->driver_data; 444 struct async_icount cnow; 445 unsigned long flags; 446 bool ret; 447 448 /* 449 * Use tty-port initialised flag to detect all hangups including the 450 * one generated at USB-device disconnect. 451 */ 452 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) 453 return true; 454 455 spin_lock_irqsave(&port->lock, flags); 456 cnow = port->icount; /* atomic copy*/ 457 spin_unlock_irqrestore(&port->lock, flags); 458 459 ret = ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) || 460 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) || 461 ((arg & TIOCM_CD) && (cnow.dcd != cprev->dcd)) || 462 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts)); 463 464 *cprev = cnow; 465 466 return ret; 467 } 468 469 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg) 470 { 471 struct usb_serial_port *port = tty->driver_data; 472 struct async_icount cnow; 473 unsigned long flags; 474 int ret; 475 476 spin_lock_irqsave(&port->lock, flags); 477 cnow = port->icount; /* atomic copy */ 478 spin_unlock_irqrestore(&port->lock, flags); 479 480 ret = wait_event_interruptible(port->port.delta_msr_wait, 481 usb_serial_generic_msr_changed(tty, arg, &cnow)); 482 if (!ret && !test_bit(ASYNCB_INITIALIZED, &port->port.flags)) 483 ret = -EIO; 484 485 return ret; 486 } 487 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait); 488 489 int usb_serial_generic_get_icount(struct tty_struct *tty, 490 struct serial_icounter_struct *icount) 491 { 492 struct usb_serial_port *port = tty->driver_data; 493 struct async_icount cnow; 494 unsigned long flags; 495 496 spin_lock_irqsave(&port->lock, flags); 497 cnow = port->icount; /* atomic copy */ 498 spin_unlock_irqrestore(&port->lock, flags); 499 500 icount->cts = cnow.cts; 501 icount->dsr = cnow.dsr; 502 icount->rng = cnow.rng; 503 icount->dcd = cnow.dcd; 504 icount->tx = cnow.tx; 505 icount->rx = cnow.rx; 506 icount->frame = cnow.frame; 507 icount->parity = cnow.parity; 508 icount->overrun = cnow.overrun; 509 icount->brk = cnow.brk; 510 icount->buf_overrun = cnow.buf_overrun; 511 512 return 0; 513 } 514 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount); 515 516 #ifdef CONFIG_MAGIC_SYSRQ 517 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch) 518 { 519 if (port->sysrq && port->port.console) { 520 if (ch && time_before(jiffies, port->sysrq)) { 521 handle_sysrq(ch); 522 port->sysrq = 0; 523 return 1; 524 } 525 port->sysrq = 0; 526 } 527 return 0; 528 } 529 #else 530 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch) 531 { 532 return 0; 533 } 534 #endif 535 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char); 536 537 int usb_serial_handle_break(struct usb_serial_port *port) 538 { 539 if (!port->sysrq) { 540 port->sysrq = jiffies + HZ*5; 541 return 1; 542 } 543 port->sysrq = 0; 544 return 0; 545 } 546 EXPORT_SYMBOL_GPL(usb_serial_handle_break); 547 548 /** 549 * usb_serial_handle_dcd_change - handle a change of carrier detect state 550 * @port: usb-serial port 551 * @tty: tty for the port 552 * @status: new carrier detect status, nonzero if active 553 */ 554 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port, 555 struct tty_struct *tty, unsigned int status) 556 { 557 struct tty_port *port = &usb_port->port; 558 559 dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status); 560 561 if (tty) { 562 struct tty_ldisc *ld = tty_ldisc_ref(tty); 563 564 if (ld) { 565 if (ld->ops->dcd_change) 566 ld->ops->dcd_change(tty, status); 567 tty_ldisc_deref(ld); 568 } 569 } 570 571 if (status) 572 wake_up_interruptible(&port->open_wait); 573 else if (tty && !C_CLOCAL(tty)) 574 tty_hangup(tty); 575 } 576 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change); 577 578 int usb_serial_generic_resume(struct usb_serial *serial) 579 { 580 struct usb_serial_port *port; 581 int i, c = 0, r; 582 583 for (i = 0; i < serial->num_ports; i++) { 584 port = serial->port[i]; 585 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) 586 continue; 587 588 if (port->bulk_in_size) { 589 r = usb_serial_generic_submit_read_urbs(port, 590 GFP_NOIO); 591 if (r < 0) 592 c++; 593 } 594 595 if (port->bulk_out_size) { 596 r = usb_serial_generic_write_start(port, GFP_NOIO); 597 if (r < 0) 598 c++; 599 } 600 } 601 602 return c ? -EIO : 0; 603 } 604 EXPORT_SYMBOL_GPL(usb_serial_generic_resume); 605