1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 *  Driver core for serial ports
   4 *
   5 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   6 *
   7 *  Copyright 1999 ARM Limited
   8 *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   9 */
  10#include <linux/module.h>
  11#include <linux/tty.h>
  12#include <linux/tty_flip.h>
  13#include <linux/slab.h>
  14#include <linux/sched/signal.h>
  15#include <linux/init.h>
  16#include <linux/console.h>
  17#include <linux/gpio/consumer.h>
  18#include <linux/kernel.h>
  19#include <linux/of.h>
  20#include <linux/pm_runtime.h>
  21#include <linux/proc_fs.h>
  22#include <linux/seq_file.h>
  23#include <linux/device.h>
  24#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
  25#include <linux/serial_core.h>
  26#include <linux/sysrq.h>
  27#include <linux/delay.h>
  28#include <linux/mutex.h>
  29#include <linux/math64.h>
  30#include <linux/security.h>
  31
  32#include <linux/irq.h>
  33#include <linux/uaccess.h>
  34
  35#include "serial_base.h"
  36
  37/*
  38 * This is used to lock changes in serial line configuration.
  39 */
  40static DEFINE_MUTEX(port_mutex);
  41
  42/*
  43 * lockdep: port->lock is initialized in two places, but we
  44 *          want only one lock-class:
  45 */
  46static struct lock_class_key port_lock_key;
  47
  48#define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)
  49
  50/*
  51 * Max time with active RTS before/after data is sent.
  52 */
  53#define RS485_MAX_RTS_DELAY	100 /* msecs */
  54
  55static void uart_change_pm(struct uart_state *state,
  56			   enum uart_pm_state pm_state);
  57
  58static void uart_port_shutdown(struct tty_port *port);
  59
  60static int uart_dcd_enabled(struct uart_port *uport)
  61{
  62	return !!(uport->status & UPSTAT_DCD_ENABLE);
  63}
  64
  65static inline struct uart_port *uart_port_ref(struct uart_state *state)
  66{
  67	if (atomic_add_unless(&state->refcount, 1, 0))
  68		return state->uart_port;
  69	return NULL;
  70}
  71
  72static inline void uart_port_deref(struct uart_port *uport)
  73{
  74	if (atomic_dec_and_test(&uport->state->refcount))
  75		wake_up(&uport->state->remove_wait);
  76}
  77
  78#define uart_port_lock(state, flags)					\
  79	({								\
  80		struct uart_port *__uport = uart_port_ref(state);	\
  81		if (__uport)						\
  82			uart_port_lock_irqsave(__uport, &flags);	\
  83		__uport;						\
  84	})
  85
  86#define uart_port_unlock(uport, flags)					\
  87	({								\
  88		struct uart_port *__uport = uport;			\
  89		if (__uport) {						\
  90			uart_port_unlock_irqrestore(__uport, flags);	\
  91			uart_port_deref(__uport);			\
  92		}							\
  93	})
  94
  95static inline struct uart_port *uart_port_check(struct uart_state *state)
  96{
  97	lockdep_assert_held(&state->port.mutex);
  98	return state->uart_port;
  99}
 100
 101/**
 102 * uart_write_wakeup - schedule write processing
 103 * @port: port to be processed
 104 *
 105 * This routine is used by the interrupt handler to schedule processing in the
 106 * software interrupt portion of the driver. A driver is expected to call this
 107 * function when the number of characters in the transmit buffer have dropped
 108 * below a threshold.
 109 *
 110 * Locking: @port->lock should be held
 111 */
 112void uart_write_wakeup(struct uart_port *port)
 113{
 114	struct uart_state *state = port->state;
 115	/*
 116	 * This means you called this function _after_ the port was
 117	 * closed.  No cookie for you.
 118	 */
 119	BUG_ON(!state);
 120	tty_port_tty_wakeup(&state->port);
 121}
 122EXPORT_SYMBOL(uart_write_wakeup);
 123
 124static void uart_stop(struct tty_struct *tty)
 125{
 126	struct uart_state *state = tty->driver_data;
 127	struct uart_port *port;
 128	unsigned long flags;
 129
 130	port = uart_port_lock(state, flags);
 131	if (port)
 132		port->ops->stop_tx(port);
 133	uart_port_unlock(port, flags);
 134}
 135
 136static void __uart_start(struct uart_state *state)
 137{
 
 138	struct uart_port *port = state->uart_port;
 139	struct serial_port_device *port_dev;
 140	int err;
 141
 142	if (!port || port->flags & UPF_DEAD || uart_tx_stopped(port))
 143		return;
 144
 145	port_dev = port->port_dev;
 146
 147	/* Increment the runtime PM usage count for the active check below */
 148	err = pm_runtime_get(&port_dev->dev);
 149	if (err < 0 && err != -EINPROGRESS) {
 150		pm_runtime_put_noidle(&port_dev->dev);
 151		return;
 152	}
 153
 154	/*
 155	 * Start TX if enabled, and kick runtime PM. If the device is not
 156	 * enabled, serial_port_runtime_resume() calls start_tx() again
 157	 * after enabling the device.
 158	 */
 159	if (!pm_runtime_enabled(port->dev) || pm_runtime_active(&port_dev->dev))
 160		port->ops->start_tx(port);
 161	pm_runtime_mark_last_busy(&port_dev->dev);
 162	pm_runtime_put_autosuspend(&port_dev->dev);
 163}
 164
 165static void uart_start(struct tty_struct *tty)
 166{
 167	struct uart_state *state = tty->driver_data;
 168	struct uart_port *port;
 169	unsigned long flags;
 170
 171	port = uart_port_lock(state, flags);
 172	__uart_start(state);
 173	uart_port_unlock(port, flags);
 174}
 175
 176static void
 177uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
 178{
 179	unsigned long flags;
 180	unsigned int old;
 181
 182	uart_port_lock_irqsave(port, &flags);
 183	old = port->mctrl;
 184	port->mctrl = (old & ~clear) | set;
 185	if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
 186		port->ops->set_mctrl(port, port->mctrl);
 187	uart_port_unlock_irqrestore(port, flags);
 188}
 189
 190#define uart_set_mctrl(port, set)	uart_update_mctrl(port, set, 0)
 191#define uart_clear_mctrl(port, clear)	uart_update_mctrl(port, 0, clear)
 192
 193static void uart_port_dtr_rts(struct uart_port *uport, bool active)
 194{
 195	if (active)
 196		uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
 197	else
 198		uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
 199}
 200
 201/* Caller holds port mutex */
 202static void uart_change_line_settings(struct tty_struct *tty, struct uart_state *state,
 203				      const struct ktermios *old_termios)
 204{
 205	struct uart_port *uport = uart_port_check(state);
 206	struct ktermios *termios;
 207	bool old_hw_stopped;
 208
 209	/*
 210	 * If we have no tty, termios, or the port does not exist,
 211	 * then we can't set the parameters for this port.
 212	 */
 213	if (!tty || uport->type == PORT_UNKNOWN)
 214		return;
 215
 216	termios = &tty->termios;
 217	uport->ops->set_termios(uport, termios, old_termios);
 218
 219	/*
 220	 * Set modem status enables based on termios cflag
 221	 */
 222	uart_port_lock_irq(uport);
 223	if (termios->c_cflag & CRTSCTS)
 224		uport->status |= UPSTAT_CTS_ENABLE;
 225	else
 226		uport->status &= ~UPSTAT_CTS_ENABLE;
 227
 228	if (termios->c_cflag & CLOCAL)
 229		uport->status &= ~UPSTAT_DCD_ENABLE;
 230	else
 231		uport->status |= UPSTAT_DCD_ENABLE;
 232
 233	/* reset sw-assisted CTS flow control based on (possibly) new mode */
 234	old_hw_stopped = uport->hw_stopped;
 235	uport->hw_stopped = uart_softcts_mode(uport) &&
 236			    !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
 237	if (uport->hw_stopped != old_hw_stopped) {
 238		if (!old_hw_stopped)
 239			uport->ops->stop_tx(uport);
 240		else
 241			__uart_start(state);
 242	}
 243	uart_port_unlock_irq(uport);
 244}
 245
 246/*
 247 * Startup the port.  This will be called once per open.  All calls
 248 * will be serialised by the per-port mutex.
 249 */
 250static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 251			     bool init_hw)
 252{
 253	struct uart_port *uport = uart_port_check(state);
 254	unsigned long flags;
 255	unsigned long page;
 256	int retval = 0;
 257
 258	if (uport->type == PORT_UNKNOWN)
 259		return 1;
 260
 261	/*
 262	 * Make sure the device is in D0 state.
 263	 */
 264	uart_change_pm(state, UART_PM_STATE_ON);
 265
 266	/*
 267	 * Initialise and allocate the transmit and temporary
 268	 * buffer.
 269	 */
 270	page = get_zeroed_page(GFP_KERNEL);
 271	if (!page)
 272		return -ENOMEM;
 273
 274	uart_port_lock(state, flags);
 275	if (!state->xmit.buf) {
 
 
 
 
 
 276		state->xmit.buf = (unsigned char *) page;
 277		uart_circ_clear(&state->xmit);
 278		uart_port_unlock(uport, flags);
 279	} else {
 280		uart_port_unlock(uport, flags);
 281		/*
 282		 * Do not free() the page under the port lock, see
 283		 * uart_shutdown().
 284		 */
 285		free_page(page);
 286	}
 287
 288	retval = uport->ops->startup(uport);
 289	if (retval == 0) {
 290		if (uart_console(uport) && uport->cons->cflag) {
 291			tty->termios.c_cflag = uport->cons->cflag;
 292			tty->termios.c_ispeed = uport->cons->ispeed;
 293			tty->termios.c_ospeed = uport->cons->ospeed;
 294			uport->cons->cflag = 0;
 295			uport->cons->ispeed = 0;
 296			uport->cons->ospeed = 0;
 297		}
 298		/*
 299		 * Initialise the hardware port settings.
 300		 */
 301		uart_change_line_settings(tty, state, NULL);
 302
 303		/*
 304		 * Setup the RTS and DTR signals once the
 305		 * port is open and ready to respond.
 306		 */
 307		if (init_hw && C_BAUD(tty))
 308			uart_port_dtr_rts(uport, true);
 309	}
 310
 311	/*
 312	 * This is to allow setserial on this port. People may want to set
 313	 * port/irq/type and then reconfigure the port properly if it failed
 314	 * now.
 315	 */
 316	if (retval && capable(CAP_SYS_ADMIN))
 317		return 1;
 318
 319	return retval;
 320}
 321
 322static int uart_startup(struct tty_struct *tty, struct uart_state *state,
 323			bool init_hw)
 324{
 325	struct tty_port *port = &state->port;
 326	struct uart_port *uport;
 327	int retval;
 328
 329	if (tty_port_initialized(port))
 330		goto out_base_port_startup;
 331
 332	retval = uart_port_startup(tty, state, init_hw);
 333	if (retval) {
 334		set_bit(TTY_IO_ERROR, &tty->flags);
 335		return retval;
 336	}
 337
 338out_base_port_startup:
 339	uport = uart_port_check(state);
 340	if (!uport)
 341		return -EIO;
 342
 343	serial_base_port_startup(uport);
 344
 345	return 0;
 346}
 347
 348/*
 349 * This routine will shutdown a serial port; interrupts are disabled, and
 350 * DTR is dropped if the hangup on close termio flag is on.  Calls to
 351 * uart_shutdown are serialised by the per-port semaphore.
 352 *
 353 * uport == NULL if uart_port has already been removed
 354 */
 355static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 356{
 357	struct uart_port *uport = uart_port_check(state);
 358	struct tty_port *port = &state->port;
 359	unsigned long flags;
 360	char *xmit_buf = NULL;
 361
 362	/*
 363	 * Set the TTY IO error marker
 364	 */
 365	if (tty)
 366		set_bit(TTY_IO_ERROR, &tty->flags);
 367
 368	if (uport)
 369		serial_base_port_shutdown(uport);
 370
 371	if (tty_port_initialized(port)) {
 372		tty_port_set_initialized(port, false);
 373
 374		/*
 375		 * Turn off DTR and RTS early.
 376		 */
 377		if (uport && uart_console(uport) && tty) {
 378			uport->cons->cflag = tty->termios.c_cflag;
 379			uport->cons->ispeed = tty->termios.c_ispeed;
 380			uport->cons->ospeed = tty->termios.c_ospeed;
 381		}
 382
 383		if (!tty || C_HUPCL(tty))
 384			uart_port_dtr_rts(uport, false);
 385
 386		uart_port_shutdown(port);
 387	}
 388
 389	/*
 390	 * It's possible for shutdown to be called after suspend if we get
 391	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
 392	 * we don't try to resume a port that has been shutdown.
 393	 */
 394	tty_port_set_suspended(port, false);
 395
 396	/*
 397	 * Do not free() the transmit buffer page under the port lock since
 398	 * this can create various circular locking scenarios. For instance,
 399	 * console driver may need to allocate/free a debug object, which
 400	 * can endup in printk() recursion.
 401	 */
 402	uart_port_lock(state, flags);
 403	xmit_buf = state->xmit.buf;
 404	state->xmit.buf = NULL;
 405	uart_port_unlock(uport, flags);
 406
 407	free_page((unsigned long)xmit_buf);
 408}
 409
 410/**
 411 * uart_update_timeout - update per-port frame timing information
 412 * @port: uart_port structure describing the port
 413 * @cflag: termios cflag value
 414 * @baud: speed of the port
 415 *
 416 * Set the @port frame timing information from which the FIFO timeout value is
 417 * derived. The @cflag value should reflect the actual hardware settings as
 418 * number of bits, parity, stop bits and baud rate is taken into account here.
 419 *
 420 * Locking: caller is expected to take @port->lock
 
 421 */
 422void
 423uart_update_timeout(struct uart_port *port, unsigned int cflag,
 424		    unsigned int baud)
 425{
 426	u64 temp = tty_get_frame_size(cflag);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 427
 428	temp *= NSEC_PER_SEC;
 429	port->frame_time = (unsigned int)DIV64_U64_ROUND_UP(temp, baud);
 
 
 
 
 
 
 
 
 
 
 
 
 
 430}
 
 431EXPORT_SYMBOL(uart_update_timeout);
 432
 433/**
 434 * uart_get_baud_rate - return baud rate for a particular port
 435 * @port: uart_port structure describing the port in question.
 436 * @termios: desired termios settings
 437 * @old: old termios (or %NULL)
 438 * @min: minimum acceptable baud rate
 439 * @max: maximum acceptable baud rate
 440 *
 441 * Decode the termios structure into a numeric baud rate, taking account of the
 442 * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
 443 * baud.
 444 *
 445 * If the new baud rate is invalid, try the @old termios setting. If it's still
 446 * invalid, we try 9600 baud. If that is also invalid 0 is returned.
 447 *
 448 * The @termios structure is updated to reflect the baud rate we're actually
 449 * going to be using. Don't do this for the case where B0 is requested ("hang
 450 * up").
 451 *
 452 * Locking: caller dependent
 453 */
 454unsigned int
 455uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 456		   const struct ktermios *old, unsigned int min, unsigned int max)
 457{
 458	unsigned int try;
 459	unsigned int baud;
 460	unsigned int altbaud;
 461	int hung_up = 0;
 462	upf_t flags = port->flags & UPF_SPD_MASK;
 463
 464	switch (flags) {
 465	case UPF_SPD_HI:
 466		altbaud = 57600;
 467		break;
 468	case UPF_SPD_VHI:
 469		altbaud = 115200;
 470		break;
 471	case UPF_SPD_SHI:
 472		altbaud = 230400;
 473		break;
 474	case UPF_SPD_WARP:
 475		altbaud = 460800;
 476		break;
 477	default:
 478		altbaud = 38400;
 479		break;
 480	}
 481
 482	for (try = 0; try < 2; try++) {
 483		baud = tty_termios_baud_rate(termios);
 484
 485		/*
 486		 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
 487		 * Die! Die! Die!
 488		 */
 489		if (try == 0 && baud == 38400)
 490			baud = altbaud;
 491
 492		/*
 493		 * Special case: B0 rate.
 494		 */
 495		if (baud == 0) {
 496			hung_up = 1;
 497			baud = 9600;
 498		}
 499
 500		if (baud >= min && baud <= max)
 501			return baud;
 502
 503		/*
 504		 * Oops, the quotient was zero.  Try again with
 505		 * the old baud rate if possible.
 506		 */
 507		termios->c_cflag &= ~CBAUD;
 508		if (old) {
 509			baud = tty_termios_baud_rate(old);
 510			if (!hung_up)
 511				tty_termios_encode_baud_rate(termios,
 512								baud, baud);
 513			old = NULL;
 514			continue;
 515		}
 516
 517		/*
 518		 * As a last resort, if the range cannot be met then clip to
 519		 * the nearest chip supported rate.
 520		 */
 521		if (!hung_up) {
 522			if (baud <= min)
 523				tty_termios_encode_baud_rate(termios,
 524							min + 1, min + 1);
 525			else
 526				tty_termios_encode_baud_rate(termios,
 527							max - 1, max - 1);
 528		}
 529	}
 
 
 530	return 0;
 531}
 
 532EXPORT_SYMBOL(uart_get_baud_rate);
 533
 534/**
 535 * uart_get_divisor - return uart clock divisor
 536 * @port: uart_port structure describing the port
 537 * @baud: desired baud rate
 538 *
 539 * Calculate the divisor (baud_base / baud) for the specified @baud,
 540 * appropriately rounded.
 541 *
 542 * If 38400 baud and custom divisor is selected, return the custom divisor
 543 * instead.
 544 *
 545 * Locking: caller dependent
 546 */
 547unsigned int
 548uart_get_divisor(struct uart_port *port, unsigned int baud)
 549{
 550	unsigned int quot;
 551
 552	/*
 553	 * Old custom speed handling.
 554	 */
 555	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
 556		quot = port->custom_divisor;
 557	else
 558		quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
 559
 560	return quot;
 561}
 
 562EXPORT_SYMBOL(uart_get_divisor);
 563
 564static int uart_put_char(struct tty_struct *tty, u8 c)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 565{
 566	struct uart_state *state = tty->driver_data;
 567	struct uart_port *port;
 568	struct circ_buf *circ;
 569	unsigned long flags;
 570	int ret = 0;
 571
 572	circ = &state->xmit;
 573	port = uart_port_lock(state, flags);
 574	if (!circ->buf) {
 575		uart_port_unlock(port, flags);
 576		return 0;
 577	}
 578
 
 579	if (port && uart_circ_chars_free(circ) != 0) {
 580		circ->buf[circ->head] = c;
 581		circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
 582		ret = 1;
 583	}
 584	uart_port_unlock(port, flags);
 585	return ret;
 586}
 587
 588static void uart_flush_chars(struct tty_struct *tty)
 589{
 590	uart_start(tty);
 591}
 592
 593static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
 
 594{
 595	struct uart_state *state = tty->driver_data;
 596	struct uart_port *port;
 597	struct circ_buf *circ;
 598	unsigned long flags;
 599	int c, ret = 0;
 600
 601	/*
 602	 * This means you called this function _after_ the port was
 603	 * closed.  No cookie for you.
 604	 */
 605	if (WARN_ON(!state))
 
 606		return -EL3HLT;
 
 607
 608	port = uart_port_lock(state, flags);
 609	circ = &state->xmit;
 610	if (!circ->buf) {
 611		uart_port_unlock(port, flags);
 612		return 0;
 613	}
 614
 
 615	while (port) {
 616		c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
 617		if (count < c)
 618			c = count;
 619		if (c <= 0)
 620			break;
 621		memcpy(circ->buf + circ->head, buf, c);
 622		circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
 623		buf += c;
 624		count -= c;
 625		ret += c;
 626	}
 627
 628	__uart_start(state);
 629	uart_port_unlock(port, flags);
 630	return ret;
 631}
 632
 633static unsigned int uart_write_room(struct tty_struct *tty)
 634{
 635	struct uart_state *state = tty->driver_data;
 636	struct uart_port *port;
 637	unsigned long flags;
 638	unsigned int ret;
 639
 640	port = uart_port_lock(state, flags);
 641	ret = uart_circ_chars_free(&state->xmit);
 642	uart_port_unlock(port, flags);
 643	return ret;
 644}
 645
 646static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
 647{
 648	struct uart_state *state = tty->driver_data;
 649	struct uart_port *port;
 650	unsigned long flags;
 651	unsigned int ret;
 652
 653	port = uart_port_lock(state, flags);
 654	ret = uart_circ_chars_pending(&state->xmit);
 655	uart_port_unlock(port, flags);
 656	return ret;
 657}
 658
 659static void uart_flush_buffer(struct tty_struct *tty)
 660{
 661	struct uart_state *state = tty->driver_data;
 662	struct uart_port *port;
 663	unsigned long flags;
 664
 665	/*
 666	 * This means you called this function _after_ the port was
 667	 * closed.  No cookie for you.
 668	 */
 669	if (WARN_ON(!state))
 
 670		return;
 
 671
 672	pr_debug("uart_flush_buffer(%d) called\n", tty->index);
 673
 674	port = uart_port_lock(state, flags);
 675	if (!port)
 676		return;
 677	uart_circ_clear(&state->xmit);
 678	if (port->ops->flush_buffer)
 679		port->ops->flush_buffer(port);
 680	uart_port_unlock(port, flags);
 681	tty_port_tty_wakeup(&state->port);
 682}
 683
 684/*
 685 * This function performs low-level write of high-priority XON/XOFF
 686 * character and accounting for it.
 687 *
 688 * Requires uart_port to implement .serial_out().
 689 */
 690void uart_xchar_out(struct uart_port *uport, int offset)
 691{
 692	serial_port_out(uport, offset, uport->x_char);
 693	uport->icount.tx++;
 694	uport->x_char = 0;
 695}
 696EXPORT_SYMBOL_GPL(uart_xchar_out);
 697
 698/*
 699 * This function is used to send a high-priority XON/XOFF character to
 700 * the device
 701 */
 702static void uart_send_xchar(struct tty_struct *tty, u8 ch)
 703{
 704	struct uart_state *state = tty->driver_data;
 705	struct uart_port *port;
 706	unsigned long flags;
 707
 708	port = uart_port_ref(state);
 709	if (!port)
 710		return;
 711
 712	if (port->ops->send_xchar)
 713		port->ops->send_xchar(port, ch);
 714	else {
 715		uart_port_lock_irqsave(port, &flags);
 716		port->x_char = ch;
 717		if (ch)
 718			port->ops->start_tx(port);
 719		uart_port_unlock_irqrestore(port, flags);
 720	}
 721	uart_port_deref(port);
 722}
 723
 724static void uart_throttle(struct tty_struct *tty)
 725{
 726	struct uart_state *state = tty->driver_data;
 727	upstat_t mask = UPSTAT_SYNC_FIFO;
 728	struct uart_port *port;
 
 729
 730	port = uart_port_ref(state);
 731	if (!port)
 732		return;
 733
 734	if (I_IXOFF(tty))
 735		mask |= UPSTAT_AUTOXOFF;
 736	if (C_CRTSCTS(tty))
 737		mask |= UPSTAT_AUTORTS;
 738
 739	if (port->status & mask) {
 740		port->ops->throttle(port);
 741		mask &= ~port->status;
 742	}
 743
 744	if (mask & UPSTAT_AUTORTS)
 745		uart_clear_mctrl(port, TIOCM_RTS);
 746
 747	if (mask & UPSTAT_AUTOXOFF)
 748		uart_send_xchar(tty, STOP_CHAR(tty));
 749
 750	uart_port_deref(port);
 751}
 752
 753static void uart_unthrottle(struct tty_struct *tty)
 754{
 755	struct uart_state *state = tty->driver_data;
 756	upstat_t mask = UPSTAT_SYNC_FIFO;
 757	struct uart_port *port;
 
 758
 759	port = uart_port_ref(state);
 760	if (!port)
 761		return;
 762
 763	if (I_IXOFF(tty))
 764		mask |= UPSTAT_AUTOXOFF;
 765	if (C_CRTSCTS(tty))
 766		mask |= UPSTAT_AUTORTS;
 767
 768	if (port->status & mask) {
 769		port->ops->unthrottle(port);
 770		mask &= ~port->status;
 771	}
 772
 773	if (mask & UPSTAT_AUTORTS)
 774		uart_set_mctrl(port, TIOCM_RTS);
 775
 776	if (mask & UPSTAT_AUTOXOFF)
 777		uart_send_xchar(tty, START_CHAR(tty));
 778
 779	uart_port_deref(port);
 780}
 781
 782static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
 783{
 784	struct uart_state *state = container_of(port, struct uart_state, port);
 785	struct uart_port *uport;
 786	int ret = -ENODEV;
 787
 788	/* Initialize structure in case we error out later to prevent any stack info leakage. */
 789	*retinfo = (struct serial_struct){};
 790
 791	/*
 792	 * Ensure the state we copy is consistent and no hardware changes
 793	 * occur as we go
 794	 */
 795	mutex_lock(&port->mutex);
 796	uport = uart_port_check(state);
 797	if (!uport)
 798		goto out;
 799
 800	retinfo->type	    = uport->type;
 801	retinfo->line	    = uport->line;
 802	retinfo->port	    = uport->iobase;
 803	if (HIGH_BITS_OFFSET)
 804		retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
 805	retinfo->irq		    = uport->irq;
 806	retinfo->flags	    = (__force int)uport->flags;
 807	retinfo->xmit_fifo_size  = uport->fifosize;
 808	retinfo->baud_base	    = uport->uartclk / 16;
 809	retinfo->close_delay	    = jiffies_to_msecs(port->close_delay) / 10;
 810	retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 811				ASYNC_CLOSING_WAIT_NONE :
 812				jiffies_to_msecs(port->closing_wait) / 10;
 813	retinfo->custom_divisor  = uport->custom_divisor;
 814	retinfo->hub6	    = uport->hub6;
 815	retinfo->io_type         = uport->iotype;
 816	retinfo->iomem_reg_shift = uport->regshift;
 817	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
 818
 819	ret = 0;
 820out:
 821	mutex_unlock(&port->mutex);
 822	return ret;
 823}
 824
 825static int uart_get_info_user(struct tty_struct *tty,
 826			 struct serial_struct *ss)
 827{
 828	struct uart_state *state = tty->driver_data;
 829	struct tty_port *port = &state->port;
 830
 831	return uart_get_info(port, ss) < 0 ? -EIO : 0;
 
 
 
 
 
 832}
 833
 834static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 835			 struct uart_state *state,
 836			 struct serial_struct *new_info)
 837{
 838	struct uart_port *uport = uart_port_check(state);
 839	unsigned long new_port;
 840	unsigned int change_irq, change_port, closing_wait;
 841	unsigned int old_custom_divisor, close_delay;
 842	upf_t old_flags, new_flags;
 843	int retval = 0;
 844
 845	if (!uport)
 846		return -EIO;
 847
 848	new_port = new_info->port;
 849	if (HIGH_BITS_OFFSET)
 850		new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
 851
 852	new_info->irq = irq_canonicalize(new_info->irq);
 853	close_delay = msecs_to_jiffies(new_info->close_delay * 10);
 854	closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 855			ASYNC_CLOSING_WAIT_NONE :
 856			msecs_to_jiffies(new_info->closing_wait * 10);
 857
 858
 859	change_irq  = !(uport->flags & UPF_FIXED_PORT)
 860		&& new_info->irq != uport->irq;
 861
 862	/*
 863	 * Since changing the 'type' of the port changes its resource
 864	 * allocations, we should treat type changes the same as
 865	 * IO port changes.
 866	 */
 867	change_port = !(uport->flags & UPF_FIXED_PORT)
 868		&& (new_port != uport->iobase ||
 869		    (unsigned long)new_info->iomem_base != uport->mapbase ||
 870		    new_info->hub6 != uport->hub6 ||
 871		    new_info->io_type != uport->iotype ||
 872		    new_info->iomem_reg_shift != uport->regshift ||
 873		    new_info->type != uport->type);
 874
 875	old_flags = uport->flags;
 876	new_flags = (__force upf_t)new_info->flags;
 877	old_custom_divisor = uport->custom_divisor;
 878
 879	if (!capable(CAP_SYS_ADMIN)) {
 880		retval = -EPERM;
 881		if (change_irq || change_port ||
 882		    (new_info->baud_base != uport->uartclk / 16) ||
 883		    (close_delay != port->close_delay) ||
 884		    (closing_wait != port->closing_wait) ||
 885		    (new_info->xmit_fifo_size &&
 886		     new_info->xmit_fifo_size != uport->fifosize) ||
 887		    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
 888			goto exit;
 889		uport->flags = ((uport->flags & ~UPF_USR_MASK) |
 890			       (new_flags & UPF_USR_MASK));
 891		uport->custom_divisor = new_info->custom_divisor;
 892		goto check_and_exit;
 893	}
 894
 895	if (change_irq || change_port) {
 896		retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
 897		if (retval)
 898			goto exit;
 899	}
 900
 901	/*
 902	 * Ask the low level driver to verify the settings.
 903	 */
 904	if (uport->ops->verify_port)
 905		retval = uport->ops->verify_port(uport, new_info);
 906
 907	if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
 908	    (new_info->baud_base < 9600))
 909		retval = -EINVAL;
 910
 911	if (retval)
 912		goto exit;
 913
 914	if (change_port || change_irq) {
 915		retval = -EBUSY;
 916
 917		/*
 918		 * Make sure that we are the sole user of this port.
 919		 */
 920		if (tty_port_users(port) > 1)
 921			goto exit;
 922
 923		/*
 924		 * We need to shutdown the serial port at the old
 925		 * port/type/irq combination.
 926		 */
 927		uart_shutdown(tty, state);
 928	}
 929
 930	if (change_port) {
 931		unsigned long old_iobase, old_mapbase;
 932		unsigned int old_type, old_iotype, old_hub6, old_shift;
 933
 934		old_iobase = uport->iobase;
 935		old_mapbase = uport->mapbase;
 936		old_type = uport->type;
 937		old_hub6 = uport->hub6;
 938		old_iotype = uport->iotype;
 939		old_shift = uport->regshift;
 940
 941		/*
 942		 * Free and release old regions
 943		 */
 944		if (old_type != PORT_UNKNOWN && uport->ops->release_port)
 945			uport->ops->release_port(uport);
 946
 947		uport->iobase = new_port;
 948		uport->type = new_info->type;
 949		uport->hub6 = new_info->hub6;
 950		uport->iotype = new_info->io_type;
 951		uport->regshift = new_info->iomem_reg_shift;
 952		uport->mapbase = (unsigned long)new_info->iomem_base;
 953
 954		/*
 955		 * Claim and map the new regions
 956		 */
 957		if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
 958			retval = uport->ops->request_port(uport);
 959		} else {
 960			/* Always success - Jean II */
 961			retval = 0;
 962		}
 963
 964		/*
 965		 * If we fail to request resources for the
 966		 * new port, try to restore the old settings.
 967		 */
 968		if (retval) {
 969			uport->iobase = old_iobase;
 970			uport->type = old_type;
 971			uport->hub6 = old_hub6;
 972			uport->iotype = old_iotype;
 973			uport->regshift = old_shift;
 974			uport->mapbase = old_mapbase;
 975
 976			if (old_type != PORT_UNKNOWN) {
 977				retval = uport->ops->request_port(uport);
 978				/*
 979				 * If we failed to restore the old settings,
 980				 * we fail like this.
 981				 */
 982				if (retval)
 983					uport->type = PORT_UNKNOWN;
 984
 985				/*
 986				 * We failed anyway.
 987				 */
 988				retval = -EBUSY;
 989			}
 990
 991			/* Added to return the correct error -Ram Gupta */
 992			goto exit;
 993		}
 994	}
 995
 996	if (change_irq)
 997		uport->irq      = new_info->irq;
 998	if (!(uport->flags & UPF_FIXED_PORT))
 999		uport->uartclk  = new_info->baud_base * 16;
1000	uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
1001				 (new_flags & UPF_CHANGE_MASK);
1002	uport->custom_divisor   = new_info->custom_divisor;
1003	port->close_delay     = close_delay;
1004	port->closing_wait    = closing_wait;
1005	if (new_info->xmit_fifo_size)
1006		uport->fifosize = new_info->xmit_fifo_size;
 
1007
1008 check_and_exit:
1009	retval = 0;
1010	if (uport->type == PORT_UNKNOWN)
1011		goto exit;
1012	if (tty_port_initialized(port)) {
1013		if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
1014		    old_custom_divisor != uport->custom_divisor) {
1015			/*
1016			 * If they're setting up a custom divisor or speed,
1017			 * instead of clearing it, then bitch about it.
 
1018			 */
1019			if (uport->flags & UPF_SPD_MASK) {
1020				dev_notice_ratelimited(uport->dev,
1021				       "%s sets custom speed on %s. This is deprecated.\n",
1022				      current->comm,
1023				      tty_name(port->tty));
1024			}
1025			uart_change_line_settings(tty, state, NULL);
1026		}
1027	} else {
1028		retval = uart_startup(tty, state, true);
1029		if (retval == 0)
1030			tty_port_set_initialized(port, true);
1031		if (retval > 0)
1032			retval = 0;
1033	}
1034 exit:
1035	return retval;
1036}
1037
1038static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
 
1039{
1040	struct uart_state *state = tty->driver_data;
1041	struct tty_port *port = &state->port;
1042	int retval;
1043
1044	down_write(&tty->termios_rwsem);
 
 
1045	/*
1046	 * This semaphore protects port->count.  It is also
1047	 * very useful to prevent opens.  Also, take the
1048	 * port configuration semaphore to make sure that a
1049	 * module insertion/removal doesn't change anything
1050	 * under us.
1051	 */
1052	mutex_lock(&port->mutex);
1053	retval = uart_set_info(tty, port, state, ss);
1054	mutex_unlock(&port->mutex);
1055	up_write(&tty->termios_rwsem);
1056	return retval;
1057}
1058
1059/**
1060 * uart_get_lsr_info - get line status register info
1061 * @tty: tty associated with the UART
1062 * @state: UART being queried
1063 * @value: returned modem value
1064 */
1065static int uart_get_lsr_info(struct tty_struct *tty,
1066			struct uart_state *state, unsigned int __user *value)
1067{
1068	struct uart_port *uport = uart_port_check(state);
1069	unsigned int result;
1070
1071	result = uport->ops->tx_empty(uport);
1072
1073	/*
1074	 * If we're about to load something into the transmit
1075	 * register, we'll pretend the transmitter isn't empty to
1076	 * avoid a race condition (depending on when the transmit
1077	 * interrupt happens).
1078	 */
1079	if (uport->x_char ||
1080	    ((uart_circ_chars_pending(&state->xmit) > 0) &&
1081	     !uart_tx_stopped(uport)))
1082		result &= ~TIOCSER_TEMT;
1083
1084	return put_user(result, value);
1085}
1086
1087static int uart_tiocmget(struct tty_struct *tty)
1088{
1089	struct uart_state *state = tty->driver_data;
1090	struct tty_port *port = &state->port;
1091	struct uart_port *uport;
1092	int result = -EIO;
1093
1094	mutex_lock(&port->mutex);
1095	uport = uart_port_check(state);
1096	if (!uport)
1097		goto out;
1098
1099	if (!tty_io_error(tty)) {
1100		uart_port_lock_irq(uport);
1101		result = uport->mctrl;
 
1102		result |= uport->ops->get_mctrl(uport);
1103		uart_port_unlock_irq(uport);
1104	}
1105out:
1106	mutex_unlock(&port->mutex);
1107	return result;
1108}
1109
1110static int
1111uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1112{
1113	struct uart_state *state = tty->driver_data;
1114	struct tty_port *port = &state->port;
1115	struct uart_port *uport;
1116	int ret = -EIO;
1117
1118	mutex_lock(&port->mutex);
1119	uport = uart_port_check(state);
1120	if (!uport)
1121		goto out;
1122
1123	if (!tty_io_error(tty)) {
1124		uart_update_mctrl(uport, set, clear);
1125		ret = 0;
1126	}
1127out:
1128	mutex_unlock(&port->mutex);
1129	return ret;
1130}
1131
1132static int uart_break_ctl(struct tty_struct *tty, int break_state)
1133{
1134	struct uart_state *state = tty->driver_data;
1135	struct tty_port *port = &state->port;
1136	struct uart_port *uport;
1137	int ret = -EIO;
1138
1139	mutex_lock(&port->mutex);
1140	uport = uart_port_check(state);
1141	if (!uport)
1142		goto out;
1143
1144	if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1145		uport->ops->break_ctl(uport, break_state);
1146	ret = 0;
1147out:
1148	mutex_unlock(&port->mutex);
1149	return ret;
1150}
1151
1152static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1153{
1154	struct tty_port *port = &state->port;
1155	struct uart_port *uport;
1156	int flags, ret;
1157
1158	if (!capable(CAP_SYS_ADMIN))
1159		return -EPERM;
1160
1161	/*
1162	 * Take the per-port semaphore.  This prevents count from
1163	 * changing, and hence any extra opens of the port while
1164	 * we're auto-configuring.
1165	 */
1166	if (mutex_lock_interruptible(&port->mutex))
1167		return -ERESTARTSYS;
1168
1169	uport = uart_port_check(state);
1170	if (!uport) {
1171		ret = -EIO;
1172		goto out;
1173	}
1174
1175	ret = -EBUSY;
1176	if (tty_port_users(port) == 1) {
1177		uart_shutdown(tty, state);
1178
1179		/*
1180		 * If we already have a port type configured,
1181		 * we must release its resources.
1182		 */
1183		if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1184			uport->ops->release_port(uport);
1185
1186		flags = UART_CONFIG_TYPE;
1187		if (uport->flags & UPF_AUTO_IRQ)
1188			flags |= UART_CONFIG_IRQ;
1189
1190		/*
1191		 * This will claim the ports resources if
1192		 * a port is found.
1193		 */
1194		uport->ops->config_port(uport, flags);
1195
1196		ret = uart_startup(tty, state, true);
1197		if (ret == 0)
1198			tty_port_set_initialized(port, true);
1199		if (ret > 0)
1200			ret = 0;
1201	}
1202out:
1203	mutex_unlock(&port->mutex);
1204	return ret;
1205}
1206
1207static void uart_enable_ms(struct uart_port *uport)
1208{
1209	/*
1210	 * Force modem status interrupts on
1211	 */
1212	if (uport->ops->enable_ms)
1213		uport->ops->enable_ms(uport);
1214}
1215
1216/*
1217 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1218 * - mask passed in arg for lines of interest
1219 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1220 * Caller should use TIOCGICOUNT to see which one it was
1221 *
1222 * FIXME: This wants extracting into a common all driver implementation
1223 * of TIOCMWAIT using tty_port.
1224 */
1225static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1226{
1227	struct uart_port *uport;
1228	struct tty_port *port = &state->port;
1229	DECLARE_WAITQUEUE(wait, current);
1230	struct uart_icount cprev, cnow;
1231	int ret;
1232
1233	/*
1234	 * note the counters on entry
1235	 */
1236	uport = uart_port_ref(state);
1237	if (!uport)
1238		return -EIO;
1239	uart_port_lock_irq(uport);
1240	memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1241	uart_enable_ms(uport);
1242	uart_port_unlock_irq(uport);
1243
1244	add_wait_queue(&port->delta_msr_wait, &wait);
1245	for (;;) {
1246		uart_port_lock_irq(uport);
1247		memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1248		uart_port_unlock_irq(uport);
1249
1250		set_current_state(TASK_INTERRUPTIBLE);
1251
1252		if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1253		    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1254		    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1255		    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1256			ret = 0;
1257			break;
1258		}
1259
1260		schedule();
1261
1262		/* see if a signal did it */
1263		if (signal_pending(current)) {
1264			ret = -ERESTARTSYS;
1265			break;
1266		}
1267
1268		cprev = cnow;
1269	}
1270	__set_current_state(TASK_RUNNING);
1271	remove_wait_queue(&port->delta_msr_wait, &wait);
1272	uart_port_deref(uport);
1273
1274	return ret;
1275}
1276
1277/*
1278 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1279 * Return: write counters to the user passed counter struct
1280 * NB: both 1->0 and 0->1 transitions are counted except for
1281 *     RI where only 0->1 is counted.
1282 */
1283static int uart_get_icount(struct tty_struct *tty,
1284			  struct serial_icounter_struct *icount)
1285{
1286	struct uart_state *state = tty->driver_data;
1287	struct uart_icount cnow;
1288	struct uart_port *uport;
1289
1290	uport = uart_port_ref(state);
1291	if (!uport)
1292		return -EIO;
1293	uart_port_lock_irq(uport);
1294	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1295	uart_port_unlock_irq(uport);
1296	uart_port_deref(uport);
1297
1298	icount->cts         = cnow.cts;
1299	icount->dsr         = cnow.dsr;
1300	icount->rng         = cnow.rng;
1301	icount->dcd         = cnow.dcd;
1302	icount->rx          = cnow.rx;
1303	icount->tx          = cnow.tx;
1304	icount->frame       = cnow.frame;
1305	icount->overrun     = cnow.overrun;
1306	icount->parity      = cnow.parity;
1307	icount->brk         = cnow.brk;
1308	icount->buf_overrun = cnow.buf_overrun;
1309
1310	return 0;
1311}
1312
1313#define SER_RS485_LEGACY_FLAGS	(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1314				 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1315				 SER_RS485_TERMINATE_BUS)
1316
1317static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1318{
1319	u32 flags = rs485->flags;
1320
1321	/* Don't return -EINVAL for unsupported legacy flags */
1322	flags &= ~SER_RS485_LEGACY_FLAGS;
1323
1324	/*
1325	 * For any bit outside of the legacy ones that is not supported by
1326	 * the driver, return -EINVAL.
1327	 */
1328	if (flags & ~port->rs485_supported.flags)
1329		return -EINVAL;
1330
1331	/* Asking for address w/o addressing mode? */
1332	if (!(rs485->flags & SER_RS485_ADDRB) &&
1333	    (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1334		return -EINVAL;
1335
1336	/* Address given but not enabled? */
1337	if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1338		return -EINVAL;
1339	if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1340		return -EINVAL;
1341
1342	return 0;
1343}
1344
1345static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1346					      struct serial_rs485 *rs485)
1347{
1348	if (!port->rs485_supported.delay_rts_before_send) {
1349		if (rs485->delay_rts_before_send) {
1350			dev_warn_ratelimited(port->dev,
1351				"%s (%d): RTS delay before sending not supported\n",
1352				port->name, port->line);
1353		}
1354		rs485->delay_rts_before_send = 0;
1355	} else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1356		rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1357		dev_warn_ratelimited(port->dev,
1358			"%s (%d): RTS delay before sending clamped to %u ms\n",
1359			port->name, port->line, rs485->delay_rts_before_send);
1360	}
1361
1362	if (!port->rs485_supported.delay_rts_after_send) {
1363		if (rs485->delay_rts_after_send) {
1364			dev_warn_ratelimited(port->dev,
1365				"%s (%d): RTS delay after sending not supported\n",
1366				port->name, port->line);
1367		}
1368		rs485->delay_rts_after_send = 0;
1369	} else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1370		rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1371		dev_warn_ratelimited(port->dev,
1372			"%s (%d): RTS delay after sending clamped to %u ms\n",
1373			port->name, port->line, rs485->delay_rts_after_send);
1374	}
1375}
1376
1377static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1378{
1379	u32 supported_flags = port->rs485_supported.flags;
1380
1381	if (!(rs485->flags & SER_RS485_ENABLED)) {
1382		memset(rs485, 0, sizeof(*rs485));
1383		return;
1384	}
1385
1386	/* Clear other RS485 flags but SER_RS485_TERMINATE_BUS and return if enabling RS422 */
1387	if (rs485->flags & SER_RS485_MODE_RS422) {
1388		rs485->flags &= (SER_RS485_ENABLED | SER_RS485_MODE_RS422 | SER_RS485_TERMINATE_BUS);
1389		return;
1390	}
1391
1392	rs485->flags &= supported_flags;
1393
1394	/* Pick sane settings if the user hasn't */
1395	if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1396	    !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1397		if (supported_flags & SER_RS485_RTS_ON_SEND) {
1398			rs485->flags |= SER_RS485_RTS_ON_SEND;
1399			rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1400
1401			dev_warn_ratelimited(port->dev,
1402				"%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1403				port->name, port->line);
1404		} else {
1405			rs485->flags |= SER_RS485_RTS_AFTER_SEND;
1406			rs485->flags &= ~SER_RS485_RTS_ON_SEND;
1407
1408			dev_warn_ratelimited(port->dev,
1409				"%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n",
1410				port->name, port->line);
1411		}
1412	}
1413
1414	uart_sanitize_serial_rs485_delays(port, rs485);
1415
1416	/* Return clean padding area to userspace */
1417	memset(rs485->padding0, 0, sizeof(rs485->padding0));
1418	memset(rs485->padding1, 0, sizeof(rs485->padding1));
1419}
1420
1421static void uart_set_rs485_termination(struct uart_port *port,
1422				       const struct serial_rs485 *rs485)
1423{
1424	if (!(rs485->flags & SER_RS485_ENABLED))
1425		return;
1426
1427	gpiod_set_value_cansleep(port->rs485_term_gpio,
1428				 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1429}
1430
1431static void uart_set_rs485_rx_during_tx(struct uart_port *port,
1432					const struct serial_rs485 *rs485)
1433{
1434	if (!(rs485->flags & SER_RS485_ENABLED))
1435		return;
1436
1437	gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1438				 !!(rs485->flags & SER_RS485_RX_DURING_TX));
1439}
1440
1441static int uart_rs485_config(struct uart_port *port)
1442{
1443	struct serial_rs485 *rs485 = &port->rs485;
1444	unsigned long flags;
1445	int ret;
1446
1447	if (!(rs485->flags & SER_RS485_ENABLED))
1448		return 0;
1449
1450	uart_sanitize_serial_rs485(port, rs485);
1451	uart_set_rs485_termination(port, rs485);
1452	uart_set_rs485_rx_during_tx(port, rs485);
1453
1454	uart_port_lock_irqsave(port, &flags);
1455	ret = port->rs485_config(port, NULL, rs485);
1456	uart_port_unlock_irqrestore(port, flags);
1457	if (ret) {
1458		memset(rs485, 0, sizeof(*rs485));
1459		/* unset GPIOs */
1460		gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
1461		gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
1462	}
1463
1464	return ret;
1465}
1466
1467static int uart_get_rs485_config(struct uart_port *port,
1468			 struct serial_rs485 __user *rs485)
1469{
1470	unsigned long flags;
1471	struct serial_rs485 aux;
1472
1473	uart_port_lock_irqsave(port, &flags);
1474	aux = port->rs485;
1475	uart_port_unlock_irqrestore(port, flags);
1476
1477	if (copy_to_user(rs485, &aux, sizeof(aux)))
1478		return -EFAULT;
1479
1480	return 0;
1481}
1482
1483static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1484			 struct serial_rs485 __user *rs485_user)
1485{
1486	struct serial_rs485 rs485;
1487	int ret;
1488	unsigned long flags;
1489
1490	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
1491		return -ENOTTY;
1492
1493	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1494		return -EFAULT;
1495
1496	ret = uart_check_rs485_flags(port, &rs485);
 
 
1497	if (ret)
1498		return ret;
1499	uart_sanitize_serial_rs485(port, &rs485);
1500	uart_set_rs485_termination(port, &rs485);
1501	uart_set_rs485_rx_during_tx(port, &rs485);
1502
1503	uart_port_lock_irqsave(port, &flags);
1504	ret = port->rs485_config(port, &tty->termios, &rs485);
1505	if (!ret) {
1506		port->rs485 = rs485;
1507
1508		/* Reset RTS and other mctrl lines when disabling RS485 */
1509		if (!(rs485.flags & SER_RS485_ENABLED))
1510			port->ops->set_mctrl(port, port->mctrl);
1511	}
1512	uart_port_unlock_irqrestore(port, flags);
1513	if (ret) {
1514		/* restore old GPIO settings */
1515		gpiod_set_value_cansleep(port->rs485_term_gpio,
1516			!!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
1517		gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1518			!!(port->rs485.flags & SER_RS485_RX_DURING_TX));
1519		return ret;
1520	}
1521
1522	if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1523		return -EFAULT;
1524
1525	return 0;
1526}
1527
1528static int uart_get_iso7816_config(struct uart_port *port,
1529				   struct serial_iso7816 __user *iso7816)
1530{
1531	unsigned long flags;
1532	struct serial_iso7816 aux;
1533
1534	if (!port->iso7816_config)
1535		return -ENOTTY;
1536
1537	uart_port_lock_irqsave(port, &flags);
1538	aux = port->iso7816;
1539	uart_port_unlock_irqrestore(port, flags);
1540
1541	if (copy_to_user(iso7816, &aux, sizeof(aux)))
1542		return -EFAULT;
1543
1544	return 0;
1545}
1546
1547static int uart_set_iso7816_config(struct uart_port *port,
1548				   struct serial_iso7816 __user *iso7816_user)
1549{
1550	struct serial_iso7816 iso7816;
1551	int i, ret;
1552	unsigned long flags;
1553
1554	if (!port->iso7816_config)
1555		return -ENOTTY;
1556
1557	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1558		return -EFAULT;
1559
1560	/*
1561	 * There are 5 words reserved for future use. Check that userspace
1562	 * doesn't put stuff in there to prevent breakages in the future.
1563	 */
1564	for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1565		if (iso7816.reserved[i])
1566			return -EINVAL;
1567
1568	uart_port_lock_irqsave(port, &flags);
1569	ret = port->iso7816_config(port, &iso7816);
1570	uart_port_unlock_irqrestore(port, flags);
1571	if (ret)
1572		return ret;
1573
1574	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1575		return -EFAULT;
1576
1577	return 0;
1578}
1579
1580/*
1581 * Called via sys_ioctl.  We can use spin_lock_irq() here.
1582 */
1583static int
1584uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1585{
1586	struct uart_state *state = tty->driver_data;
1587	struct tty_port *port = &state->port;
1588	struct uart_port *uport;
1589	void __user *uarg = (void __user *)arg;
1590	int ret = -ENOIOCTLCMD;
1591
1592
1593	/*
1594	 * These ioctls don't rely on the hardware to be present.
1595	 */
1596	switch (cmd) {
 
 
 
 
 
 
 
 
 
 
1597	case TIOCSERCONFIG:
1598		down_write(&tty->termios_rwsem);
1599		ret = uart_do_autoconfig(tty, state);
1600		up_write(&tty->termios_rwsem);
1601		break;
 
 
 
 
 
1602	}
1603
1604	if (ret != -ENOIOCTLCMD)
1605		goto out;
1606
1607	if (tty_io_error(tty)) {
1608		ret = -EIO;
1609		goto out;
1610	}
1611
1612	/*
1613	 * The following should only be used when hardware is present.
1614	 */
1615	switch (cmd) {
1616	case TIOCMIWAIT:
1617		ret = uart_wait_modem_status(state, arg);
1618		break;
1619	}
1620
1621	if (ret != -ENOIOCTLCMD)
1622		goto out;
1623
1624	/* rs485_config requires more locking than others */
1625	if (cmd == TIOCSRS485)
1626		down_write(&tty->termios_rwsem);
1627
1628	mutex_lock(&port->mutex);
1629	uport = uart_port_check(state);
1630
1631	if (!uport || tty_io_error(tty)) {
1632		ret = -EIO;
1633		goto out_up;
1634	}
1635
1636	/*
1637	 * All these rely on hardware being present and need to be
1638	 * protected against the tty being hung up.
1639	 */
1640
1641	switch (cmd) {
1642	case TIOCSERGETLSR: /* Get line status register */
1643		ret = uart_get_lsr_info(tty, state, uarg);
1644		break;
1645
1646	case TIOCGRS485:
1647		ret = uart_get_rs485_config(uport, uarg);
1648		break;
1649
1650	case TIOCSRS485:
1651		ret = uart_set_rs485_config(tty, uport, uarg);
1652		break;
1653
1654	case TIOCSISO7816:
1655		ret = uart_set_iso7816_config(state->uart_port, uarg);
1656		break;
1657
1658	case TIOCGISO7816:
1659		ret = uart_get_iso7816_config(state->uart_port, uarg);
1660		break;
1661	default:
1662		if (uport->ops->ioctl)
1663			ret = uport->ops->ioctl(uport, cmd, arg);
1664		break;
1665	}
1666out_up:
1667	mutex_unlock(&port->mutex);
1668	if (cmd == TIOCSRS485)
1669		up_write(&tty->termios_rwsem);
1670out:
1671	return ret;
1672}
1673
1674static void uart_set_ldisc(struct tty_struct *tty)
1675{
1676	struct uart_state *state = tty->driver_data;
1677	struct uart_port *uport;
1678	struct tty_port *port = &state->port;
1679
1680	if (!tty_port_initialized(port))
1681		return;
1682
1683	mutex_lock(&state->port.mutex);
1684	uport = uart_port_check(state);
1685	if (uport && uport->ops->set_ldisc)
1686		uport->ops->set_ldisc(uport, &tty->termios);
1687	mutex_unlock(&state->port.mutex);
1688}
1689
1690static void uart_set_termios(struct tty_struct *tty,
1691			     const struct ktermios *old_termios)
1692{
1693	struct uart_state *state = tty->driver_data;
1694	struct uart_port *uport;
1695	unsigned int cflag = tty->termios.c_cflag;
1696	unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1697	bool sw_changed = false;
1698
1699	mutex_lock(&state->port.mutex);
1700	uport = uart_port_check(state);
1701	if (!uport)
1702		goto out;
1703
1704	/*
1705	 * Drivers doing software flow control also need to know
1706	 * about changes to these input settings.
1707	 */
1708	if (uport->flags & UPF_SOFT_FLOW) {
1709		iflag_mask |= IXANY|IXON|IXOFF;
1710		sw_changed =
1711		   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1712		   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1713	}
1714
1715	/*
1716	 * These are the bits that are used to setup various
1717	 * flags in the low level driver. We can ignore the Bfoo
1718	 * bits in c_cflag; c_[io]speed will always be set
1719	 * appropriately by set_termios() in tty_ioctl.c
1720	 */
1721	if ((cflag ^ old_termios->c_cflag) == 0 &&
1722	    tty->termios.c_ospeed == old_termios->c_ospeed &&
1723	    tty->termios.c_ispeed == old_termios->c_ispeed &&
1724	    ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1725	    !sw_changed) {
1726		goto out;
1727	}
1728
1729	uart_change_line_settings(tty, state, old_termios);
1730	/* reload cflag from termios; port driver may have overridden flags */
1731	cflag = tty->termios.c_cflag;
1732
1733	/* Handle transition to B0 status */
1734	if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1735		uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1736	/* Handle transition away from B0 status */
1737	else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1738		unsigned int mask = TIOCM_DTR;
1739
1740		if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1741			mask |= TIOCM_RTS;
1742		uart_set_mctrl(uport, mask);
1743	}
1744out:
1745	mutex_unlock(&state->port.mutex);
1746}
1747
1748/*
1749 * Calls to uart_close() are serialised via the tty_lock in
1750 *   drivers/tty/tty_io.c:tty_release()
1751 *   drivers/tty/tty_io.c:do_tty_hangup()
1752 */
1753static void uart_close(struct tty_struct *tty, struct file *filp)
1754{
1755	struct uart_state *state = tty->driver_data;
 
1756
1757	if (!state) {
1758		struct uart_driver *drv = tty->driver->driver_state;
1759		struct tty_port *port;
1760
1761		state = drv->state + tty->index;
1762		port = &state->port;
1763		spin_lock_irq(&port->lock);
1764		--port->count;
1765		spin_unlock_irq(&port->lock);
1766		return;
1767	}
1768
 
1769	pr_debug("uart_close(%d) called\n", tty->index);
1770
1771	tty_port_close(tty->port, tty, filp);
1772}
1773
1774static void uart_tty_port_shutdown(struct tty_port *port)
1775{
1776	struct uart_state *state = container_of(port, struct uart_state, port);
1777	struct uart_port *uport = uart_port_check(state);
1778	char *buf;
1779
1780	/*
1781	 * At this point, we stop accepting input.  To do this, we
1782	 * disable the receive line status interrupts.
1783	 */
1784	if (WARN(!uport, "detached port still initialized!\n"))
1785		return;
1786
1787	uart_port_lock_irq(uport);
1788	uport->ops->stop_rx(uport);
1789	uart_port_unlock_irq(uport);
1790
1791	serial_base_port_shutdown(uport);
1792	uart_port_shutdown(port);
1793
1794	/*
1795	 * It's possible for shutdown to be called after suspend if we get
1796	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
1797	 * we don't try to resume a port that has been shutdown.
1798	 */
1799	tty_port_set_suspended(port, false);
1800
1801	/*
1802	 * Free the transmit buffer.
1803	 */
1804	uart_port_lock_irq(uport);
1805	uart_circ_clear(&state->xmit);
1806	buf = state->xmit.buf;
1807	state->xmit.buf = NULL;
1808	uart_port_unlock_irq(uport);
1809
1810	free_page((unsigned long)buf);
1811
1812	uart_change_pm(state, UART_PM_STATE_OFF);
 
1813}
1814
1815static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1816{
1817	struct uart_state *state = tty->driver_data;
1818	struct uart_port *port;
1819	unsigned long char_time, expire, fifo_timeout;
1820
1821	port = uart_port_ref(state);
1822	if (!port)
1823		return;
1824
1825	if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1826		uart_port_deref(port);
1827		return;
1828	}
1829
1830	/*
1831	 * Set the check interval to be 1/5 of the estimated time to
1832	 * send a single character, and make it at least 1.  The check
1833	 * interval should also be less than the timeout.
1834	 *
1835	 * Note: we have to use pretty tight timings here to satisfy
1836	 * the NIST-PCTS.
1837	 */
1838	char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1839
 
 
1840	if (timeout && timeout < char_time)
1841		char_time = timeout;
1842
1843	if (!uart_cts_enabled(port)) {
1844		/*
1845		 * If the transmitter hasn't cleared in twice the approximate
1846		 * amount of time to send the entire FIFO, it probably won't
1847		 * ever clear.  This assumes the UART isn't doing flow
1848		 * control, which is currently the case.  Hence, if it ever
1849		 * takes longer than FIFO timeout, this is probably due to a
1850		 * UART bug of some kind.  So, we clamp the timeout parameter at
1851		 * 2 * FIFO timeout.
1852		 */
1853		fifo_timeout = uart_fifo_timeout(port);
1854		if (timeout == 0 || timeout > 2 * fifo_timeout)
1855			timeout = 2 * fifo_timeout;
1856	}
1857
1858	expire = jiffies + timeout;
1859
1860	pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1861		port->line, jiffies, expire);
1862
1863	/*
1864	 * Check whether the transmitter is empty every 'char_time'.
1865	 * 'timeout' / 'expire' give us the maximum amount of time
1866	 * we wait.
1867	 */
1868	while (!port->ops->tx_empty(port)) {
1869		msleep_interruptible(jiffies_to_msecs(char_time));
1870		if (signal_pending(current))
1871			break;
1872		if (timeout && time_after(jiffies, expire))
1873			break;
1874	}
1875	uart_port_deref(port);
1876}
1877
1878/*
1879 * Calls to uart_hangup() are serialised by the tty_lock in
1880 *   drivers/tty/tty_io.c:do_tty_hangup()
1881 * This runs from a workqueue and can sleep for a _short_ time only.
1882 */
1883static void uart_hangup(struct tty_struct *tty)
1884{
1885	struct uart_state *state = tty->driver_data;
1886	struct tty_port *port = &state->port;
1887	struct uart_port *uport;
1888	unsigned long flags;
1889
1890	pr_debug("uart_hangup(%d)\n", tty->index);
1891
1892	mutex_lock(&port->mutex);
1893	uport = uart_port_check(state);
1894	WARN(!uport, "hangup of detached port!\n");
1895
1896	if (tty_port_active(port)) {
1897		uart_flush_buffer(tty);
1898		uart_shutdown(tty, state);
1899		spin_lock_irqsave(&port->lock, flags);
1900		port->count = 0;
1901		spin_unlock_irqrestore(&port->lock, flags);
1902		tty_port_set_active(port, false);
1903		tty_port_tty_set(port, NULL);
1904		if (uport && !uart_console(uport))
1905			uart_change_pm(state, UART_PM_STATE_OFF);
1906		wake_up_interruptible(&port->open_wait);
1907		wake_up_interruptible(&port->delta_msr_wait);
1908	}
1909	mutex_unlock(&port->mutex);
1910}
1911
1912/* uport == NULL if uart_port has already been removed */
1913static void uart_port_shutdown(struct tty_port *port)
1914{
1915	struct uart_state *state = container_of(port, struct uart_state, port);
1916	struct uart_port *uport = uart_port_check(state);
1917
1918	/*
1919	 * clear delta_msr_wait queue to avoid mem leaks: we may free
1920	 * the irq here so the queue might never be woken up.  Note
1921	 * that we won't end up waiting on delta_msr_wait again since
1922	 * any outstanding file descriptors should be pointing at
1923	 * hung_up_tty_fops now.
1924	 */
1925	wake_up_interruptible(&port->delta_msr_wait);
1926
1927	if (uport) {
1928		/* Free the IRQ and disable the port. */
 
 
1929		uport->ops->shutdown(uport);
1930
1931		/* Ensure that the IRQ handler isn't running on another CPU. */
 
 
 
1932		synchronize_irq(uport->irq);
1933	}
1934}
1935
1936static bool uart_carrier_raised(struct tty_port *port)
1937{
1938	struct uart_state *state = container_of(port, struct uart_state, port);
1939	struct uart_port *uport;
1940	int mctrl;
1941
1942	uport = uart_port_ref(state);
1943	/*
1944	 * Should never observe uport == NULL since checks for hangup should
1945	 * abort the tty_port_block_til_ready() loop before checking for carrier
1946	 * raised -- but report carrier raised if it does anyway so open will
1947	 * continue and not sleep
1948	 */
1949	if (WARN_ON(!uport))
1950		return true;
1951	uart_port_lock_irq(uport);
1952	uart_enable_ms(uport);
1953	mctrl = uport->ops->get_mctrl(uport);
1954	uart_port_unlock_irq(uport);
1955	uart_port_deref(uport);
1956
1957	return mctrl & TIOCM_CAR;
 
1958}
1959
1960static void uart_dtr_rts(struct tty_port *port, bool active)
1961{
1962	struct uart_state *state = container_of(port, struct uart_state, port);
1963	struct uart_port *uport;
1964
1965	uport = uart_port_ref(state);
1966	if (!uport)
1967		return;
1968	uart_port_dtr_rts(uport, active);
1969	uart_port_deref(uport);
1970}
1971
1972static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1973{
1974	struct uart_driver *drv = driver->driver_state;
1975	struct uart_state *state = drv->state + tty->index;
1976
1977	tty->driver_data = state;
1978
1979	return tty_standard_install(driver, tty);
1980}
1981
1982/*
1983 * Calls to uart_open are serialised by the tty_lock in
1984 *   drivers/tty/tty_io.c:tty_open()
1985 * Note that if this fails, then uart_close() _will_ be called.
1986 *
1987 * In time, we want to scrap the "opening nonpresent ports"
1988 * behaviour and implement an alternative way for setserial
1989 * to set base addresses/ports/types.  This will allow us to
1990 * get rid of a certain amount of extra tests.
1991 */
1992static int uart_open(struct tty_struct *tty, struct file *filp)
1993{
1994	struct uart_state *state = tty->driver_data;
1995	int retval;
 
 
 
1996
1997	retval = tty_port_open(&state->port, tty, filp);
1998	if (retval > 0)
1999		retval = 0;
2000
2001	return retval;
2002}
2003
2004static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
2005{
2006	struct uart_state *state = container_of(port, struct uart_state, port);
2007	struct uart_port *uport;
2008	int ret;
2009
2010	uport = uart_port_check(state);
2011	if (!uport || uport->flags & UPF_DEAD)
2012		return -ENXIO;
2013
 
 
2014	/*
2015	 * Start up the serial port.
2016	 */
2017	ret = uart_startup(tty, state, false);
2018	if (ret > 0)
2019		tty_port_set_active(port, true);
2020
2021	return ret;
2022}
2023
2024static const char *uart_type(struct uart_port *port)
2025{
2026	const char *str = NULL;
2027
2028	if (port->ops->type)
2029		str = port->ops->type(port);
2030
2031	if (!str)
2032		str = "unknown";
2033
2034	return str;
2035}
2036
2037#ifdef CONFIG_PROC_FS
2038
2039static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
2040{
2041	struct uart_state *state = drv->state + i;
2042	struct tty_port *port = &state->port;
2043	enum uart_pm_state pm_state;
2044	struct uart_port *uport;
2045	char stat_buf[32];
2046	unsigned int status;
2047	int mmio;
2048
2049	mutex_lock(&port->mutex);
2050	uport = uart_port_check(state);
2051	if (!uport)
2052		goto out;
2053
2054	mmio = uport->iotype >= UPIO_MEM;
2055	seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
2056			uport->line, uart_type(uport),
2057			mmio ? "mmio:0x" : "port:",
2058			mmio ? (unsigned long long)uport->mapbase
2059			     : (unsigned long long)uport->iobase,
2060			uport->irq);
2061
2062	if (uport->type == PORT_UNKNOWN) {
2063		seq_putc(m, '\n');
2064		goto out;
2065	}
2066
2067	if (capable(CAP_SYS_ADMIN)) {
2068		pm_state = state->pm_state;
2069		if (pm_state != UART_PM_STATE_ON)
2070			uart_change_pm(state, UART_PM_STATE_ON);
2071		uart_port_lock_irq(uport);
2072		status = uport->ops->get_mctrl(uport);
2073		uart_port_unlock_irq(uport);
2074		if (pm_state != UART_PM_STATE_ON)
2075			uart_change_pm(state, pm_state);
2076
2077		seq_printf(m, " tx:%d rx:%d",
2078				uport->icount.tx, uport->icount.rx);
2079		if (uport->icount.frame)
2080			seq_printf(m, " fe:%d",	uport->icount.frame);
2081		if (uport->icount.parity)
2082			seq_printf(m, " pe:%d",	uport->icount.parity);
2083		if (uport->icount.brk)
2084			seq_printf(m, " brk:%d", uport->icount.brk);
2085		if (uport->icount.overrun)
2086			seq_printf(m, " oe:%d", uport->icount.overrun);
2087		if (uport->icount.buf_overrun)
2088			seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2089
2090#define INFOBIT(bit, str) \
2091	if (uport->mctrl & (bit)) \
2092		strncat(stat_buf, (str), sizeof(stat_buf) - \
2093			strlen(stat_buf) - 2)
2094#define STATBIT(bit, str) \
2095	if (status & (bit)) \
2096		strncat(stat_buf, (str), sizeof(stat_buf) - \
2097		       strlen(stat_buf) - 2)
2098
2099		stat_buf[0] = '\0';
2100		stat_buf[1] = '\0';
2101		INFOBIT(TIOCM_RTS, "|RTS");
2102		STATBIT(TIOCM_CTS, "|CTS");
2103		INFOBIT(TIOCM_DTR, "|DTR");
2104		STATBIT(TIOCM_DSR, "|DSR");
2105		STATBIT(TIOCM_CAR, "|CD");
2106		STATBIT(TIOCM_RNG, "|RI");
2107		if (stat_buf[0])
2108			stat_buf[0] = ' ';
2109
2110		seq_puts(m, stat_buf);
2111	}
2112	seq_putc(m, '\n');
2113#undef STATBIT
2114#undef INFOBIT
2115out:
2116	mutex_unlock(&port->mutex);
2117}
2118
2119static int uart_proc_show(struct seq_file *m, void *v)
2120{
2121	struct tty_driver *ttydrv = m->private;
2122	struct uart_driver *drv = ttydrv->driver_state;
2123	int i;
2124
2125	seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2126	for (i = 0; i < drv->nr; i++)
2127		uart_line_info(m, drv, i);
2128	return 0;
2129}
2130#endif
2131
2132static void uart_port_spin_lock_init(struct uart_port *port)
2133{
2134	spin_lock_init(&port->lock);
2135	lockdep_set_class(&port->lock, &port_lock_key);
2136}
2137
 
 
 
 
 
 
 
 
 
2138#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2139/**
2140 * uart_console_write - write a console message to a serial port
2141 * @port: the port to write the message
2142 * @s: array of characters
2143 * @count: number of characters in string to write
2144 * @putchar: function to write character to port
2145 */
2146void uart_console_write(struct uart_port *port, const char *s,
2147			unsigned int count,
2148			void (*putchar)(struct uart_port *, unsigned char))
2149{
2150	unsigned int i;
2151
2152	for (i = 0; i < count; i++, s++) {
2153		if (*s == '\n')
2154			putchar(port, '\r');
2155		putchar(port, *s);
2156	}
2157}
2158EXPORT_SYMBOL_GPL(uart_console_write);
2159
2160/**
2161 * uart_get_console - get uart port for console
2162 * @ports: ports to search in
2163 * @nr: number of @ports
2164 * @co: console to search for
2165 * Returns: uart_port for the console @co
2166 *
2167 * Check whether an invalid uart number has been specified (as @co->index), and
2168 * if so, search for the first available port that does have console support.
2169 */
2170struct uart_port * __init
2171uart_get_console(struct uart_port *ports, int nr, struct console *co)
2172{
2173	int idx = co->index;
2174
2175	if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2176				     ports[idx].membase == NULL))
2177		for (idx = 0; idx < nr; idx++)
2178			if (ports[idx].iobase != 0 ||
2179			    ports[idx].membase != NULL)
2180				break;
2181
2182	co->index = idx;
2183
2184	return ports + idx;
2185}
2186
2187/**
2188 * uart_parse_earlycon - Parse earlycon options
2189 * @p:	     ptr to 2nd field (ie., just beyond '<name>,')
2190 * @iotype:  ptr for decoded iotype (out)
2191 * @addr:    ptr for decoded mapbase/iobase (out)
2192 * @options: ptr for <options> field; %NULL if not present (out)
2193 *
2194 * Decodes earlycon kernel command line parameters of the form:
2195 *  * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2196 *  * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2197 *
2198 * The optional form:
2199 *  * earlycon=<name>,0x<addr>,<options>
2200 *  * console=<name>,0x<addr>,<options>
2201 *
2202 * is also accepted; the returned @iotype will be %UPIO_MEM.
2203 *
2204 * Returns: 0 on success or -%EINVAL on failure
2205 */
2206int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2207			char **options)
2208{
2209	if (strncmp(p, "mmio,", 5) == 0) {
2210		*iotype = UPIO_MEM;
2211		p += 5;
2212	} else if (strncmp(p, "mmio16,", 7) == 0) {
2213		*iotype = UPIO_MEM16;
2214		p += 7;
2215	} else if (strncmp(p, "mmio32,", 7) == 0) {
2216		*iotype = UPIO_MEM32;
2217		p += 7;
2218	} else if (strncmp(p, "mmio32be,", 9) == 0) {
2219		*iotype = UPIO_MEM32BE;
2220		p += 9;
2221	} else if (strncmp(p, "mmio32native,", 13) == 0) {
2222		*iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2223			UPIO_MEM32BE : UPIO_MEM32;
2224		p += 13;
2225	} else if (strncmp(p, "io,", 3) == 0) {
2226		*iotype = UPIO_PORT;
2227		p += 3;
2228	} else if (strncmp(p, "0x", 2) == 0) {
2229		*iotype = UPIO_MEM;
2230	} else {
2231		return -EINVAL;
2232	}
2233
2234	/*
2235	 * Before you replace it with kstrtoull(), think about options separator
2236	 * (',') it will not tolerate
2237	 */
2238	*addr = simple_strtoull(p, NULL, 0);
2239	p = strchr(p, ',');
2240	if (p)
2241		p++;
2242
2243	*options = p;
2244	return 0;
2245}
2246EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2247
2248/**
2249 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2250 * @options: pointer to option string
2251 * @baud: pointer to an 'int' variable for the baud rate.
2252 * @parity: pointer to an 'int' variable for the parity.
2253 * @bits: pointer to an 'int' variable for the number of data bits.
2254 * @flow: pointer to an 'int' variable for the flow control character.
2255 *
2256 * uart_parse_options() decodes a string containing the serial console
2257 * options. The format of the string is <baud><parity><bits><flow>,
2258 * eg: 115200n8r
2259 */
2260void
2261uart_parse_options(const char *options, int *baud, int *parity,
2262		   int *bits, int *flow)
2263{
2264	const char *s = options;
2265
2266	*baud = simple_strtoul(s, NULL, 10);
2267	while (*s >= '0' && *s <= '9')
2268		s++;
2269	if (*s)
2270		*parity = *s++;
2271	if (*s)
2272		*bits = *s++ - '0';
2273	if (*s)
2274		*flow = *s;
2275}
2276EXPORT_SYMBOL_GPL(uart_parse_options);
2277
2278/**
2279 * uart_set_options - setup the serial console parameters
2280 * @port: pointer to the serial ports uart_port structure
2281 * @co: console pointer
2282 * @baud: baud rate
2283 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2284 * @bits: number of data bits
2285 * @flow: flow control character - 'r' (rts)
2286 *
2287 * Locking: Caller must hold console_list_lock in order to serialize
2288 * early initialization of the serial-console lock.
2289 */
2290int
2291uart_set_options(struct uart_port *port, struct console *co,
2292		 int baud, int parity, int bits, int flow)
2293{
2294	struct ktermios termios;
2295	static struct ktermios dummy;
2296
2297	/*
2298	 * Ensure that the serial-console lock is initialised early.
2299	 *
2300	 * Note that the console-registered check is needed because
2301	 * kgdboc can call uart_set_options() for an already registered
2302	 * console via tty_find_polling_driver() and uart_poll_init().
2303	 */
2304	if (!uart_console_registered_locked(port) && !port->console_reinit)
2305		uart_port_spin_lock_init(port);
 
 
2306
2307	memset(&termios, 0, sizeof(struct ktermios));
2308
2309	termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2310	tty_termios_encode_baud_rate(&termios, baud, baud);
2311
2312	if (bits == 7)
2313		termios.c_cflag |= CS7;
2314	else
2315		termios.c_cflag |= CS8;
2316
2317	switch (parity) {
2318	case 'o': case 'O':
2319		termios.c_cflag |= PARODD;
2320		fallthrough;
2321	case 'e': case 'E':
2322		termios.c_cflag |= PARENB;
2323		break;
2324	}
2325
2326	if (flow == 'r')
2327		termios.c_cflag |= CRTSCTS;
2328
2329	/*
2330	 * some uarts on other side don't support no flow control.
2331	 * So we set * DTR in host uart to make them happy
2332	 */
2333	port->mctrl |= TIOCM_DTR;
2334
2335	port->ops->set_termios(port, &termios, &dummy);
2336	/*
2337	 * Allow the setting of the UART parameters with a NULL console
2338	 * too:
2339	 */
2340	if (co) {
2341		co->cflag = termios.c_cflag;
2342		co->ispeed = termios.c_ispeed;
2343		co->ospeed = termios.c_ospeed;
2344	}
2345
2346	return 0;
2347}
2348EXPORT_SYMBOL_GPL(uart_set_options);
2349#endif /* CONFIG_SERIAL_CORE_CONSOLE */
2350
2351/**
2352 * uart_change_pm - set power state of the port
2353 *
2354 * @state: port descriptor
2355 * @pm_state: new state
2356 *
2357 * Locking: port->mutex has to be held
2358 */
2359static void uart_change_pm(struct uart_state *state,
2360			   enum uart_pm_state pm_state)
2361{
2362	struct uart_port *port = uart_port_check(state);
2363
2364	if (state->pm_state != pm_state) {
2365		if (port && port->ops->pm)
2366			port->ops->pm(port, pm_state, state->pm_state);
2367		state->pm_state = pm_state;
2368	}
2369}
2370
2371struct uart_match {
2372	struct uart_port *port;
2373	struct uart_driver *driver;
2374};
2375
2376static int serial_match_port(struct device *dev, void *data)
2377{
2378	struct uart_match *match = data;
2379	struct tty_driver *tty_drv = match->driver->tty_driver;
2380	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2381		match->port->line;
2382
2383	return dev->devt == devt; /* Actually, only one tty per port */
2384}
2385
2386int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2387{
2388	struct uart_state *state = drv->state + uport->line;
2389	struct tty_port *port = &state->port;
2390	struct device *tty_dev;
2391	struct uart_match match = {uport, drv};
2392
2393	mutex_lock(&port->mutex);
2394
2395	tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);
2396	if (tty_dev && device_may_wakeup(tty_dev)) {
2397		enable_irq_wake(uport->irq);
 
2398		put_device(tty_dev);
2399		mutex_unlock(&port->mutex);
2400		return 0;
2401	}
2402	put_device(tty_dev);
2403
2404	/*
2405	 * Nothing to do if the console is not suspending
2406	 * except stop_rx to prevent any asynchronous data
2407	 * over RX line. However ensure that we will be
2408	 * able to Re-start_rx later.
2409	 */
2410	if (!console_suspend_enabled && uart_console(uport)) {
2411		if (uport->ops->start_rx) {
2412			uart_port_lock_irq(uport);
2413			uport->ops->stop_rx(uport);
2414			uart_port_unlock_irq(uport);
2415		}
2416		goto unlock;
2417	}
2418
2419	uport->suspended = 1;
2420
2421	if (tty_port_initialized(port)) {
2422		const struct uart_ops *ops = uport->ops;
2423		int tries;
2424		unsigned int mctrl;
2425
2426		tty_port_set_suspended(port, true);
2427		tty_port_set_initialized(port, false);
2428
2429		uart_port_lock_irq(uport);
2430		ops->stop_tx(uport);
2431		if (!(uport->rs485.flags & SER_RS485_ENABLED))
2432			ops->set_mctrl(uport, 0);
2433		/* save mctrl so it can be restored on resume */
2434		mctrl = uport->mctrl;
2435		uport->mctrl = 0;
2436		ops->stop_rx(uport);
2437		uart_port_unlock_irq(uport);
2438
2439		/*
2440		 * Wait for the transmitter to empty.
2441		 */
2442		for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2443			msleep(10);
2444		if (!tries)
2445			dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2446				uport->name);
 
2447
2448		ops->shutdown(uport);
2449		uport->mctrl = mctrl;
2450	}
2451
2452	/*
2453	 * Disable the console device before suspending.
2454	 */
2455	if (uart_console(uport))
2456		console_stop(uport->cons);
2457
2458	uart_change_pm(state, UART_PM_STATE_OFF);
2459unlock:
2460	mutex_unlock(&port->mutex);
2461
2462	return 0;
2463}
2464EXPORT_SYMBOL(uart_suspend_port);
2465
2466int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2467{
2468	struct uart_state *state = drv->state + uport->line;
2469	struct tty_port *port = &state->port;
2470	struct device *tty_dev;
2471	struct uart_match match = {uport, drv};
2472	struct ktermios termios;
2473
2474	mutex_lock(&port->mutex);
2475
2476	tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);
2477	if (!uport->suspended && device_may_wakeup(tty_dev)) {
2478		if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2479			disable_irq_wake(uport->irq);
 
 
2480		put_device(tty_dev);
2481		mutex_unlock(&port->mutex);
2482		return 0;
2483	}
2484	put_device(tty_dev);
2485	uport->suspended = 0;
2486
2487	/*
2488	 * Re-enable the console device after suspending.
2489	 */
2490	if (uart_console(uport)) {
2491		/*
2492		 * First try to use the console cflag setting.
2493		 */
2494		memset(&termios, 0, sizeof(struct ktermios));
2495		termios.c_cflag = uport->cons->cflag;
2496		termios.c_ispeed = uport->cons->ispeed;
2497		termios.c_ospeed = uport->cons->ospeed;
2498
2499		/*
2500		 * If that's unset, use the tty termios setting.
2501		 */
2502		if (port->tty && termios.c_cflag == 0)
2503			termios = port->tty->termios;
2504
2505		if (console_suspend_enabled)
2506			uart_change_pm(state, UART_PM_STATE_ON);
2507		uport->ops->set_termios(uport, &termios, NULL);
2508		if (!console_suspend_enabled && uport->ops->start_rx) {
2509			uart_port_lock_irq(uport);
2510			uport->ops->start_rx(uport);
2511			uart_port_unlock_irq(uport);
2512		}
2513		if (console_suspend_enabled)
2514			console_start(uport->cons);
2515	}
2516
2517	if (tty_port_suspended(port)) {
2518		const struct uart_ops *ops = uport->ops;
2519		int ret;
2520
2521		uart_change_pm(state, UART_PM_STATE_ON);
2522		uart_port_lock_irq(uport);
2523		if (!(uport->rs485.flags & SER_RS485_ENABLED))
2524			ops->set_mctrl(uport, 0);
2525		uart_port_unlock_irq(uport);
2526		if (console_suspend_enabled || !uart_console(uport)) {
2527			/* Protected by port mutex for now */
2528			struct tty_struct *tty = port->tty;
2529
2530			ret = ops->startup(uport);
2531			if (ret == 0) {
2532				if (tty)
2533					uart_change_line_settings(tty, state, NULL);
2534				uart_rs485_config(uport);
2535				uart_port_lock_irq(uport);
2536				if (!(uport->rs485.flags & SER_RS485_ENABLED))
2537					ops->set_mctrl(uport, uport->mctrl);
2538				ops->start_tx(uport);
2539				uart_port_unlock_irq(uport);
2540				tty_port_set_initialized(port, true);
2541			} else {
2542				/*
2543				 * Failed to resume - maybe hardware went away?
2544				 * Clear the "initialized" flag so we won't try
2545				 * to call the low level drivers shutdown method.
2546				 */
2547				uart_shutdown(tty, state);
2548			}
2549		}
2550
2551		tty_port_set_suspended(port, false);
2552	}
2553
2554	mutex_unlock(&port->mutex);
2555
2556	return 0;
2557}
2558EXPORT_SYMBOL(uart_resume_port);
2559
2560static inline void
2561uart_report_port(struct uart_driver *drv, struct uart_port *port)
2562{
2563	char address[64];
2564
2565	switch (port->iotype) {
2566	case UPIO_PORT:
2567		snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2568		break;
2569	case UPIO_HUB6:
2570		snprintf(address, sizeof(address),
2571			 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2572		break;
2573	case UPIO_MEM:
2574	case UPIO_MEM16:
2575	case UPIO_MEM32:
2576	case UPIO_MEM32BE:
2577	case UPIO_AU:
2578	case UPIO_TSI:
2579		snprintf(address, sizeof(address),
2580			 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2581		break;
2582	default:
2583		strscpy(address, "*unknown*", sizeof(address));
2584		break;
2585	}
2586
2587	pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2588	       port->dev ? dev_name(port->dev) : "",
2589	       port->dev ? ": " : "",
2590	       port->name,
 
2591	       address, port->irq, port->uartclk / 16, uart_type(port));
2592
2593	/* The magic multiplier feature is a bit obscure, so report it too.  */
2594	if (port->flags & UPF_MAGIC_MULTIPLIER)
2595		pr_info("%s%s%s extra baud rates supported: %d, %d",
2596			port->dev ? dev_name(port->dev) : "",
2597			port->dev ? ": " : "",
2598			port->name,
2599			port->uartclk / 8, port->uartclk / 4);
2600}
2601
2602static void
2603uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2604		    struct uart_port *port)
2605{
2606	unsigned int flags;
2607
2608	/*
2609	 * If there isn't a port here, don't do anything further.
2610	 */
2611	if (!port->iobase && !port->mapbase && !port->membase)
2612		return;
2613
2614	/*
2615	 * Now do the auto configuration stuff.  Note that config_port
2616	 * is expected to claim the resources and map the port for us.
2617	 */
2618	flags = 0;
2619	if (port->flags & UPF_AUTO_IRQ)
2620		flags |= UART_CONFIG_IRQ;
2621	if (port->flags & UPF_BOOT_AUTOCONF) {
2622		if (!(port->flags & UPF_FIXED_TYPE)) {
2623			port->type = PORT_UNKNOWN;
2624			flags |= UART_CONFIG_TYPE;
2625		}
2626		/* Synchronize with possible boot console. */
2627		if (uart_console(port))
2628			console_lock();
2629		port->ops->config_port(port, flags);
2630		if (uart_console(port))
2631			console_unlock();
2632	}
2633
2634	if (port->type != PORT_UNKNOWN) {
2635		unsigned long flags;
2636
2637		uart_report_port(drv, port);
2638
2639		/* Synchronize with possible boot console. */
2640		if (uart_console(port))
2641			console_lock();
2642
2643		/* Power up port for set_mctrl() */
2644		uart_change_pm(state, UART_PM_STATE_ON);
2645
2646		/*
2647		 * Ensure that the modem control lines are de-activated.
2648		 * keep the DTR setting that is set in uart_set_options()
2649		 * We probably don't need a spinlock around this, but
2650		 */
2651		uart_port_lock_irqsave(port, &flags);
2652		port->mctrl &= TIOCM_DTR;
2653		if (!(port->rs485.flags & SER_RS485_ENABLED))
2654			port->ops->set_mctrl(port, port->mctrl);
2655		uart_port_unlock_irqrestore(port, flags);
2656
2657		uart_rs485_config(port);
2658
2659		if (uart_console(port))
2660			console_unlock();
2661
2662		/*
2663		 * If this driver supports console, and it hasn't been
2664		 * successfully registered yet, try to re-register it.
2665		 * It may be that the port was not available.
2666		 */
2667		if (port->cons && !console_is_registered(port->cons))
2668			register_console(port->cons);
2669
2670		/*
2671		 * Power down all ports by default, except the
2672		 * console if we have one.
2673		 */
2674		if (!uart_console(port))
2675			uart_change_pm(state, UART_PM_STATE_OFF);
2676	}
2677}
2678
2679#ifdef CONFIG_CONSOLE_POLL
2680
2681static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2682{
2683	struct uart_driver *drv = driver->driver_state;
2684	struct uart_state *state = drv->state + line;
2685	enum uart_pm_state pm_state;
2686	struct tty_port *tport;
2687	struct uart_port *port;
2688	int baud = 9600;
2689	int bits = 8;
2690	int parity = 'n';
2691	int flow = 'n';
2692	int ret = 0;
2693
 
 
 
2694	tport = &state->port;
2695	mutex_lock(&tport->mutex);
2696
2697	port = uart_port_check(state);
2698	if (!port || port->type == PORT_UNKNOWN ||
2699	    !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2700		ret = -1;
2701		goto out;
2702	}
2703
2704	pm_state = state->pm_state;
2705	uart_change_pm(state, UART_PM_STATE_ON);
2706
2707	if (port->ops->poll_init) {
2708		/*
2709		 * We don't set initialized as we only initialized the hw,
2710		 * e.g. state->xmit is still uninitialized.
2711		 */
2712		if (!tty_port_initialized(tport))
2713			ret = port->ops->poll_init(port);
2714	}
2715
2716	if (!ret && options) {
2717		uart_parse_options(options, &baud, &parity, &bits, &flow);
2718		console_list_lock();
2719		ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2720		console_list_unlock();
2721	}
2722out:
2723	if (ret)
2724		uart_change_pm(state, pm_state);
2725	mutex_unlock(&tport->mutex);
2726	return ret;
2727}
2728
2729static int uart_poll_get_char(struct tty_driver *driver, int line)
2730{
2731	struct uart_driver *drv = driver->driver_state;
2732	struct uart_state *state = drv->state + line;
2733	struct uart_port *port;
2734	int ret = -1;
2735
2736	port = uart_port_ref(state);
2737	if (port) {
2738		ret = port->ops->poll_get_char(port);
2739		uart_port_deref(port);
 
 
2740	}
2741
2742	return ret;
2743}
2744
2745static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2746{
2747	struct uart_driver *drv = driver->driver_state;
2748	struct uart_state *state = drv->state + line;
2749	struct uart_port *port;
2750
 
 
 
2751	port = uart_port_ref(state);
2752	if (!port)
2753		return;
2754
2755	if (ch == '\n')
2756		port->ops->poll_put_char(port, '\r');
2757	port->ops->poll_put_char(port, ch);
2758	uart_port_deref(port);
2759}
2760#endif
2761
2762static const struct tty_operations uart_ops = {
2763	.install	= uart_install,
2764	.open		= uart_open,
2765	.close		= uart_close,
2766	.write		= uart_write,
2767	.put_char	= uart_put_char,
2768	.flush_chars	= uart_flush_chars,
2769	.write_room	= uart_write_room,
2770	.chars_in_buffer= uart_chars_in_buffer,
2771	.flush_buffer	= uart_flush_buffer,
2772	.ioctl		= uart_ioctl,
2773	.throttle	= uart_throttle,
2774	.unthrottle	= uart_unthrottle,
2775	.send_xchar	= uart_send_xchar,
2776	.set_termios	= uart_set_termios,
2777	.set_ldisc	= uart_set_ldisc,
2778	.stop		= uart_stop,
2779	.start		= uart_start,
2780	.hangup		= uart_hangup,
2781	.break_ctl	= uart_break_ctl,
2782	.wait_until_sent= uart_wait_until_sent,
2783#ifdef CONFIG_PROC_FS
2784	.proc_show	= uart_proc_show,
2785#endif
2786	.tiocmget	= uart_tiocmget,
2787	.tiocmset	= uart_tiocmset,
2788	.set_serial	= uart_set_info_user,
2789	.get_serial	= uart_get_info_user,
2790	.get_icount	= uart_get_icount,
2791#ifdef CONFIG_CONSOLE_POLL
2792	.poll_init	= uart_poll_init,
2793	.poll_get_char	= uart_poll_get_char,
2794	.poll_put_char	= uart_poll_put_char,
2795#endif
2796};
2797
2798static const struct tty_port_operations uart_port_ops = {
2799	.carrier_raised = uart_carrier_raised,
2800	.dtr_rts	= uart_dtr_rts,
2801	.activate	= uart_port_activate,
2802	.shutdown	= uart_tty_port_shutdown,
2803};
2804
2805/**
2806 * uart_register_driver - register a driver with the uart core layer
2807 * @drv: low level driver structure
2808 *
2809 * Register a uart driver with the core driver. We in turn register with the
2810 * tty layer, and initialise the core driver per-port state.
2811 *
2812 * We have a proc file in /proc/tty/driver which is named after the normal
2813 * driver.
2814 *
2815 * @drv->port should be %NULL, and the per-port structures should be registered
2816 * using uart_add_one_port() after this call has succeeded.
2817 *
2818 * Locking: none, Interrupts: enabled
 
2819 */
2820int uart_register_driver(struct uart_driver *drv)
2821{
2822	struct tty_driver *normal;
2823	int i, retval = -ENOMEM;
2824
2825	BUG_ON(drv->state);
2826
2827	/*
2828	 * Maybe we should be using a slab cache for this, especially if
2829	 * we have a large number of ports to handle.
2830	 */
2831	drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2832	if (!drv->state)
2833		goto out;
2834
2835	normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2836			TTY_DRIVER_DYNAMIC_DEV);
2837	if (IS_ERR(normal)) {
2838		retval = PTR_ERR(normal);
2839		goto out_kfree;
2840	}
2841
2842	drv->tty_driver = normal;
2843
2844	normal->driver_name	= drv->driver_name;
2845	normal->name		= drv->dev_name;
2846	normal->major		= drv->major;
2847	normal->minor_start	= drv->minor;
2848	normal->type		= TTY_DRIVER_TYPE_SERIAL;
2849	normal->subtype		= SERIAL_TYPE_NORMAL;
2850	normal->init_termios	= tty_std_termios;
2851	normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2852	normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
 
2853	normal->driver_state    = drv;
2854	tty_set_operations(normal, &uart_ops);
2855
2856	/*
2857	 * Initialise the UART state(s).
2858	 */
2859	for (i = 0; i < drv->nr; i++) {
2860		struct uart_state *state = drv->state + i;
2861		struct tty_port *port = &state->port;
2862
2863		tty_port_init(port);
2864		port->ops = &uart_port_ops;
2865	}
2866
2867	retval = tty_register_driver(normal);
2868	if (retval >= 0)
2869		return retval;
2870
2871	for (i = 0; i < drv->nr; i++)
2872		tty_port_destroy(&drv->state[i].port);
2873	tty_driver_kref_put(normal);
2874out_kfree:
2875	kfree(drv->state);
2876out:
2877	return retval;
2878}
2879EXPORT_SYMBOL(uart_register_driver);
2880
2881/**
2882 * uart_unregister_driver - remove a driver from the uart core layer
2883 * @drv: low level driver structure
2884 *
2885 * Remove all references to a driver from the core driver. The low level
2886 * driver must have removed all its ports via the uart_remove_one_port() if it
2887 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2888 *
2889 * Locking: none, Interrupts: enabled
2890 */
2891void uart_unregister_driver(struct uart_driver *drv)
2892{
2893	struct tty_driver *p = drv->tty_driver;
2894	unsigned int i;
2895
2896	tty_unregister_driver(p);
2897	tty_driver_kref_put(p);
2898	for (i = 0; i < drv->nr; i++)
2899		tty_port_destroy(&drv->state[i].port);
2900	kfree(drv->state);
2901	drv->state = NULL;
2902	drv->tty_driver = NULL;
2903}
2904EXPORT_SYMBOL(uart_unregister_driver);
2905
2906struct tty_driver *uart_console_device(struct console *co, int *index)
2907{
2908	struct uart_driver *p = co->data;
2909	*index = co->index;
2910	return p->tty_driver;
2911}
2912EXPORT_SYMBOL_GPL(uart_console_device);
2913
2914static ssize_t uartclk_show(struct device *dev,
2915	struct device_attribute *attr, char *buf)
2916{
2917	struct serial_struct tmp;
2918	struct tty_port *port = dev_get_drvdata(dev);
2919
2920	uart_get_info(port, &tmp);
2921	return sprintf(buf, "%d\n", tmp.baud_base * 16);
2922}
2923
2924static ssize_t type_show(struct device *dev,
2925	struct device_attribute *attr, char *buf)
2926{
2927	struct serial_struct tmp;
2928	struct tty_port *port = dev_get_drvdata(dev);
2929
2930	uart_get_info(port, &tmp);
2931	return sprintf(buf, "%d\n", tmp.type);
2932}
2933
2934static ssize_t line_show(struct device *dev,
2935	struct device_attribute *attr, char *buf)
2936{
2937	struct serial_struct tmp;
2938	struct tty_port *port = dev_get_drvdata(dev);
2939
2940	uart_get_info(port, &tmp);
2941	return sprintf(buf, "%d\n", tmp.line);
2942}
2943
2944static ssize_t port_show(struct device *dev,
2945	struct device_attribute *attr, char *buf)
2946{
2947	struct serial_struct tmp;
2948	struct tty_port *port = dev_get_drvdata(dev);
2949	unsigned long ioaddr;
2950
2951	uart_get_info(port, &tmp);
2952	ioaddr = tmp.port;
2953	if (HIGH_BITS_OFFSET)
2954		ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2955	return sprintf(buf, "0x%lX\n", ioaddr);
2956}
2957
2958static ssize_t irq_show(struct device *dev,
2959	struct device_attribute *attr, char *buf)
2960{
2961	struct serial_struct tmp;
2962	struct tty_port *port = dev_get_drvdata(dev);
2963
2964	uart_get_info(port, &tmp);
2965	return sprintf(buf, "%d\n", tmp.irq);
2966}
2967
2968static ssize_t flags_show(struct device *dev,
2969	struct device_attribute *attr, char *buf)
2970{
2971	struct serial_struct tmp;
2972	struct tty_port *port = dev_get_drvdata(dev);
2973
2974	uart_get_info(port, &tmp);
2975	return sprintf(buf, "0x%X\n", tmp.flags);
2976}
2977
2978static ssize_t xmit_fifo_size_show(struct device *dev,
2979	struct device_attribute *attr, char *buf)
2980{
2981	struct serial_struct tmp;
2982	struct tty_port *port = dev_get_drvdata(dev);
2983
2984	uart_get_info(port, &tmp);
2985	return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2986}
2987
2988static ssize_t close_delay_show(struct device *dev,
 
2989	struct device_attribute *attr, char *buf)
2990{
2991	struct serial_struct tmp;
2992	struct tty_port *port = dev_get_drvdata(dev);
2993
2994	uart_get_info(port, &tmp);
2995	return sprintf(buf, "%d\n", tmp.close_delay);
2996}
2997
2998static ssize_t closing_wait_show(struct device *dev,
 
2999	struct device_attribute *attr, char *buf)
3000{
3001	struct serial_struct tmp;
3002	struct tty_port *port = dev_get_drvdata(dev);
3003
3004	uart_get_info(port, &tmp);
3005	return sprintf(buf, "%d\n", tmp.closing_wait);
3006}
3007
3008static ssize_t custom_divisor_show(struct device *dev,
3009	struct device_attribute *attr, char *buf)
3010{
3011	struct serial_struct tmp;
3012	struct tty_port *port = dev_get_drvdata(dev);
3013
3014	uart_get_info(port, &tmp);
3015	return sprintf(buf, "%d\n", tmp.custom_divisor);
3016}
3017
3018static ssize_t io_type_show(struct device *dev,
3019	struct device_attribute *attr, char *buf)
3020{
3021	struct serial_struct tmp;
3022	struct tty_port *port = dev_get_drvdata(dev);
3023
3024	uart_get_info(port, &tmp);
3025	return sprintf(buf, "%d\n", tmp.io_type);
3026}
3027
3028static ssize_t iomem_base_show(struct device *dev,
3029	struct device_attribute *attr, char *buf)
3030{
3031	struct serial_struct tmp;
3032	struct tty_port *port = dev_get_drvdata(dev);
3033
3034	uart_get_info(port, &tmp);
3035	return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
3036}
3037
3038static ssize_t iomem_reg_shift_show(struct device *dev,
3039	struct device_attribute *attr, char *buf)
3040{
3041	struct serial_struct tmp;
3042	struct tty_port *port = dev_get_drvdata(dev);
3043
3044	uart_get_info(port, &tmp);
3045	return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
3046}
3047
3048static ssize_t console_show(struct device *dev,
3049	struct device_attribute *attr, char *buf)
3050{
3051	struct tty_port *port = dev_get_drvdata(dev);
3052	struct uart_state *state = container_of(port, struct uart_state, port);
3053	struct uart_port *uport;
3054	bool console = false;
3055
3056	mutex_lock(&port->mutex);
3057	uport = uart_port_check(state);
3058	if (uport)
3059		console = uart_console_registered(uport);
3060	mutex_unlock(&port->mutex);
3061
3062	return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3063}
3064
3065static ssize_t console_store(struct device *dev,
3066	struct device_attribute *attr, const char *buf, size_t count)
3067{
3068	struct tty_port *port = dev_get_drvdata(dev);
3069	struct uart_state *state = container_of(port, struct uart_state, port);
3070	struct uart_port *uport;
3071	bool oldconsole, newconsole;
3072	int ret;
3073
3074	ret = kstrtobool(buf, &newconsole);
3075	if (ret)
3076		return ret;
3077
3078	mutex_lock(&port->mutex);
3079	uport = uart_port_check(state);
3080	if (uport) {
3081		oldconsole = uart_console_registered(uport);
3082		if (oldconsole && !newconsole) {
3083			ret = unregister_console(uport->cons);
3084		} else if (!oldconsole && newconsole) {
3085			if (uart_console(uport)) {
3086				uport->console_reinit = 1;
3087				register_console(uport->cons);
3088			} else {
3089				ret = -ENOENT;
3090			}
3091		}
3092	} else {
3093		ret = -ENXIO;
3094	}
3095	mutex_unlock(&port->mutex);
3096
3097	return ret < 0 ? ret : count;
3098}
3099
3100static DEVICE_ATTR_RO(uartclk);
3101static DEVICE_ATTR_RO(type);
3102static DEVICE_ATTR_RO(line);
3103static DEVICE_ATTR_RO(port);
3104static DEVICE_ATTR_RO(irq);
3105static DEVICE_ATTR_RO(flags);
3106static DEVICE_ATTR_RO(xmit_fifo_size);
3107static DEVICE_ATTR_RO(close_delay);
3108static DEVICE_ATTR_RO(closing_wait);
3109static DEVICE_ATTR_RO(custom_divisor);
3110static DEVICE_ATTR_RO(io_type);
3111static DEVICE_ATTR_RO(iomem_base);
3112static DEVICE_ATTR_RO(iomem_reg_shift);
3113static DEVICE_ATTR_RW(console);
3114
3115static struct attribute *tty_dev_attrs[] = {
3116	&dev_attr_uartclk.attr,
3117	&dev_attr_type.attr,
3118	&dev_attr_line.attr,
3119	&dev_attr_port.attr,
3120	&dev_attr_irq.attr,
3121	&dev_attr_flags.attr,
3122	&dev_attr_xmit_fifo_size.attr,
 
3123	&dev_attr_close_delay.attr,
3124	&dev_attr_closing_wait.attr,
3125	&dev_attr_custom_divisor.attr,
3126	&dev_attr_io_type.attr,
3127	&dev_attr_iomem_base.attr,
3128	&dev_attr_iomem_reg_shift.attr,
3129	&dev_attr_console.attr,
3130	NULL
3131};
3132
3133static const struct attribute_group tty_dev_attr_group = {
3134	.attrs = tty_dev_attrs,
3135};
3136
3137/**
3138 * serial_core_add_one_port - attach a driver-defined port structure
3139 * @drv: pointer to the uart low level driver structure for this port
3140 * @uport: uart port structure to use for this port.
3141 *
3142 * Context: task context, might sleep
3143 *
3144 * This allows the driver @drv to register its own uart_port structure with the
3145 * core driver. The main purpose is to allow the low level uart drivers to
3146 * expand uart_port, rather than having yet more levels of structures.
3147 * Caller must hold port_mutex.
3148 */
3149static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3150{
3151	struct uart_state *state;
3152	struct tty_port *port;
3153	int ret = 0;
3154	struct device *tty_dev;
3155	int num_groups;
3156
 
 
3157	if (uport->line >= drv->nr)
3158		return -EINVAL;
3159
3160	state = drv->state + uport->line;
3161	port = &state->port;
3162
 
3163	mutex_lock(&port->mutex);
3164	if (state->uart_port) {
3165		ret = -EINVAL;
3166		goto out;
3167	}
3168
3169	/* Link the port to the driver state table and vice versa */
3170	atomic_set(&state->refcount, 1);
3171	init_waitqueue_head(&state->remove_wait);
3172	state->uart_port = uport;
3173	uport->state = state;
3174
3175	state->pm_state = UART_PM_STATE_UNDEFINED;
3176	uport->cons = drv->cons;
3177	uport->minor = drv->tty_driver->minor_start + uport->line;
3178	uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3179				drv->tty_driver->name_base + uport->line);
3180	if (!uport->name) {
3181		ret = -ENOMEM;
3182		goto out;
3183	}
3184
3185	/*
3186	 * If this port is in use as a console then the spinlock is already
3187	 * initialised.
3188	 */
3189	if (!uart_console_registered(uport))
3190		uart_port_spin_lock_init(uport);
3191
 
3192	if (uport->cons && uport->dev)
3193		of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3194
3195	tty_port_link_device(port, drv->tty_driver, uport->line);
3196	uart_configure_port(drv, state, uport);
3197
3198	port->console = uart_console(uport);
3199
3200	num_groups = 2;
3201	if (uport->attr_group)
3202		num_groups++;
3203
3204	uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3205				    GFP_KERNEL);
3206	if (!uport->tty_groups) {
3207		ret = -ENOMEM;
3208		goto out;
3209	}
3210	uport->tty_groups[0] = &tty_dev_attr_group;
3211	if (uport->attr_group)
3212		uport->tty_groups[1] = uport->attr_group;
3213
3214	/*
3215	 * Register the port whether it's detected or not.  This allows
3216	 * setserial to be used to alter this port's parameters.
3217	 */
3218	tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3219			uport->line, uport->dev, &uport->port_dev->dev, port,
3220			uport->tty_groups);
3221	if (!IS_ERR(tty_dev)) {
3222		device_set_wakeup_capable(tty_dev, 1);
3223	} else {
3224		dev_err(uport->dev, "Cannot register tty device on line %d\n",
3225		       uport->line);
3226	}
3227
 
 
 
 
 
3228 out:
3229	mutex_unlock(&port->mutex);
 
3230
3231	return ret;
3232}
3233
3234/**
3235 * serial_core_remove_one_port - detach a driver defined port structure
3236 * @drv: pointer to the uart low level driver structure for this port
3237 * @uport: uart port structure for this port
3238 *
3239 * Context: task context, might sleep
3240 *
3241 * This unhooks (and hangs up) the specified port structure from the core
3242 * driver. No further calls will be made to the low-level code for this port.
3243 * Caller must hold port_mutex.
3244 */
3245static void serial_core_remove_one_port(struct uart_driver *drv,
3246					struct uart_port *uport)
3247{
3248	struct uart_state *state = drv->state + uport->line;
3249	struct tty_port *port = &state->port;
3250	struct uart_port *uart_port;
3251	struct tty_struct *tty;
 
3252
 
 
 
 
 
 
 
 
3253	mutex_lock(&port->mutex);
3254	uart_port = uart_port_check(state);
3255	if (uart_port != uport)
3256		dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3257			  uart_port, uport);
3258
3259	if (!uart_port) {
3260		mutex_unlock(&port->mutex);
3261		return;
 
3262	}
 
3263	mutex_unlock(&port->mutex);
3264
3265	/*
3266	 * Remove the devices from the tty layer
3267	 */
3268	tty_port_unregister_device(port, drv->tty_driver, uport->line);
3269
3270	tty = tty_port_tty_get(port);
3271	if (tty) {
3272		tty_vhangup(port->tty);
3273		tty_kref_put(tty);
3274	}
3275
3276	/*
3277	 * If the port is used as a console, unregister it
3278	 */
3279	if (uart_console(uport))
3280		unregister_console(uport->cons);
3281
3282	/*
3283	 * Free the port IO and memory resources, if any.
3284	 */
3285	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3286		uport->ops->release_port(uport);
3287	kfree(uport->tty_groups);
3288	kfree(uport->name);
3289
3290	/*
3291	 * Indicate that there isn't a port here anymore.
3292	 */
3293	uport->type = PORT_UNKNOWN;
3294	uport->port_dev = NULL;
3295
3296	mutex_lock(&port->mutex);
3297	WARN_ON(atomic_dec_return(&state->refcount) < 0);
3298	wait_event(state->remove_wait, !atomic_read(&state->refcount));
3299	state->uart_port = NULL;
3300	mutex_unlock(&port->mutex);
 
 
 
 
3301}
3302
3303/**
3304 * uart_match_port - are the two ports equivalent?
3305 * @port1: first port
3306 * @port2: second port
3307 *
3308 * This utility function can be used to determine whether two uart_port
3309 * structures describe the same port.
3310 */
3311bool uart_match_port(const struct uart_port *port1,
3312		const struct uart_port *port2)
3313{
3314	if (port1->iotype != port2->iotype)
3315		return false;
3316
3317	switch (port1->iotype) {
3318	case UPIO_PORT:
3319		return port1->iobase == port2->iobase;
3320	case UPIO_HUB6:
3321		return port1->iobase == port2->iobase &&
3322		       port1->hub6   == port2->hub6;
3323	case UPIO_MEM:
3324	case UPIO_MEM16:
3325	case UPIO_MEM32:
3326	case UPIO_MEM32BE:
3327	case UPIO_AU:
3328	case UPIO_TSI:
3329		return port1->mapbase == port2->mapbase;
3330	}
3331
3332	return false;
3333}
3334EXPORT_SYMBOL(uart_match_port);
3335
3336static struct serial_ctrl_device *
3337serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3338{
3339	struct device *dev = &port_dev->dev;
3340
3341	return to_serial_base_ctrl_device(dev->parent);
3342}
3343
3344/*
3345 * Find a registered serial core controller device if one exists. Returns
3346 * the first device matching the ctrl_id. Caller must hold port_mutex.
3347 */
3348static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,
3349							struct device *phys_dev,
3350							int ctrl_id)
3351{
3352	struct uart_state *state;
3353	int i;
3354
3355	lockdep_assert_held(&port_mutex);
3356
3357	for (i = 0; i < drv->nr; i++) {
3358		state = drv->state + i;
3359		if (!state->uart_port || !state->uart_port->port_dev)
3360			continue;
3361
3362		if (state->uart_port->dev == phys_dev &&
3363		    state->uart_port->ctrl_id == ctrl_id)
3364			return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3365	}
3366
3367	return NULL;
3368}
3369
3370static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)
3371{
3372	return serial_base_ctrl_add(port, port->dev);
3373}
3374
3375static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3376				       struct uart_port *port)
3377{
3378	struct serial_port_device *port_dev;
3379
3380	port_dev = serial_base_port_add(port, ctrl_dev);
3381	if (IS_ERR(port_dev))
3382		return PTR_ERR(port_dev);
3383
3384	port->port_dev = port_dev;
3385
3386	return 0;
3387}
3388
3389/*
3390 * Initialize a serial core port device, and a controller device if needed.
3391 */
3392int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
3393{
3394	struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
3395	int ret;
3396
3397	mutex_lock(&port_mutex);
3398
3399	/*
3400	 * Prevent serial_port_runtime_resume() from trying to use the port
3401	 * until serial_core_add_one_port() has completed
3402	 */
3403	port->flags |= UPF_DEAD;
3404
3405	/* Inititalize a serial core controller device if needed */
3406	ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3407	if (!ctrl_dev) {
3408		new_ctrl_dev = serial_core_ctrl_device_add(port);
3409		if (IS_ERR(new_ctrl_dev)) {
3410			ret = PTR_ERR(new_ctrl_dev);
3411			goto err_unlock;
3412		}
3413		ctrl_dev = new_ctrl_dev;
3414	}
3415
3416	/*
3417	 * Initialize a serial core port device. Tag the port dead to prevent
3418	 * serial_port_runtime_resume() trying to do anything until port has
3419	 * been registered. It gets cleared by serial_core_add_one_port().
3420	 */
3421	ret = serial_core_port_device_add(ctrl_dev, port);
3422	if (ret)
3423		goto err_unregister_ctrl_dev;
3424
3425	ret = serial_core_add_one_port(drv, port);
3426	if (ret)
3427		goto err_unregister_port_dev;
3428
3429	port->flags &= ~UPF_DEAD;
3430
3431	mutex_unlock(&port_mutex);
3432
3433	return 0;
3434
3435err_unregister_port_dev:
3436	serial_base_port_device_remove(port->port_dev);
3437
3438err_unregister_ctrl_dev:
3439	serial_base_ctrl_device_remove(new_ctrl_dev);
3440
3441err_unlock:
3442	mutex_unlock(&port_mutex);
3443
3444	return ret;
3445}
3446
3447/*
3448 * Removes a serial core port device, and the related serial core controller
3449 * device if the last instance.
3450 */
3451void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)
3452{
3453	struct device *phys_dev = port->dev;
3454	struct serial_port_device *port_dev = port->port_dev;
3455	struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3456	int ctrl_id = port->ctrl_id;
3457
3458	mutex_lock(&port_mutex);
3459
3460	port->flags |= UPF_DEAD;
3461
3462	serial_core_remove_one_port(drv, port);
3463
3464	/* Note that struct uart_port *port is no longer valid at this point */
3465	serial_base_port_device_remove(port_dev);
3466
3467	/* Drop the serial core controller device if no ports are using it */
3468	if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3469		serial_base_ctrl_device_remove(ctrl_dev);
3470
3471	mutex_unlock(&port_mutex);
3472}
 
3473
3474/**
3475 * uart_handle_dcd_change - handle a change of carrier detect state
3476 * @uport: uart_port structure for the open port
3477 * @active: new carrier detect status
3478 *
3479 * Caller must hold uport->lock.
3480 */
3481void uart_handle_dcd_change(struct uart_port *uport, bool active)
3482{
3483	struct tty_port *port = &uport->state->port;
3484	struct tty_struct *tty = port->tty;
3485	struct tty_ldisc *ld;
3486
3487	lockdep_assert_held_once(&uport->lock);
3488
3489	if (tty) {
3490		ld = tty_ldisc_ref(tty);
3491		if (ld) {
3492			if (ld->ops->dcd_change)
3493				ld->ops->dcd_change(tty, active);
3494			tty_ldisc_deref(ld);
3495		}
3496	}
3497
3498	uport->icount.dcd++;
3499
3500	if (uart_dcd_enabled(uport)) {
3501		if (active)
3502			wake_up_interruptible(&port->open_wait);
3503		else if (tty)
3504			tty_hangup(tty);
3505	}
3506}
3507EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3508
3509/**
3510 * uart_handle_cts_change - handle a change of clear-to-send state
3511 * @uport: uart_port structure for the open port
3512 * @active: new clear-to-send status
3513 *
3514 * Caller must hold uport->lock.
3515 */
3516void uart_handle_cts_change(struct uart_port *uport, bool active)
3517{
3518	lockdep_assert_held_once(&uport->lock);
3519
3520	uport->icount.cts++;
3521
3522	if (uart_softcts_mode(uport)) {
3523		if (uport->hw_stopped) {
3524			if (active) {
3525				uport->hw_stopped = false;
3526				uport->ops->start_tx(uport);
3527				uart_write_wakeup(uport);
3528			}
3529		} else {
3530			if (!active) {
3531				uport->hw_stopped = true;
3532				uport->ops->stop_tx(uport);
3533			}
3534		}
3535
3536	}
3537}
3538EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3539
3540/**
3541 * uart_insert_char - push a char to the uart layer
3542 *
3543 * User is responsible to call tty_flip_buffer_push when they are done with
3544 * insertion.
3545 *
3546 * @port: corresponding port
3547 * @status: state of the serial port RX buffer (LSR for 8250)
3548 * @overrun: mask of overrun bits in @status
3549 * @ch: character to push
3550 * @flag: flag for the character (see TTY_NORMAL and friends)
3551 */
3552void uart_insert_char(struct uart_port *port, unsigned int status,
3553		      unsigned int overrun, u8 ch, u8 flag)
3554{
3555	struct tty_port *tport = &port->state->port;
3556
3557	if ((status & port->ignore_status_mask & ~overrun) == 0)
3558		if (tty_insert_flip_char(tport, ch, flag) == 0)
3559			++port->icount.buf_overrun;
3560
3561	/*
3562	 * Overrun is special.  Since it's reported immediately,
3563	 * it doesn't affect the current character.
3564	 */
3565	if (status & ~port->ignore_status_mask & overrun)
3566		if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3567			++port->icount.buf_overrun;
3568}
3569EXPORT_SYMBOL_GPL(uart_insert_char);
3570
3571#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3572static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3573
3574static void uart_sysrq_on(struct work_struct *w)
3575{
3576	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3577
3578	sysrq_toggle_support(1);
3579	pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3580		sysrq_toggle_seq_len, sysrq_toggle_seq);
3581}
3582static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3583
3584/**
3585 * uart_try_toggle_sysrq - Enables SysRq from serial line
3586 * @port: uart_port structure where char(s) after BREAK met
3587 * @ch: new character in the sequence after received BREAK
3588 *
3589 * Enables magic SysRq when the required sequence is met on port
3590 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3591 *
3592 * Returns: %false if @ch is out of enabling sequence and should be
3593 * handled some other way, %true if @ch was consumed.
3594 */
3595bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)
3596{
3597	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3598
3599	if (!sysrq_toggle_seq_len)
3600		return false;
3601
3602	BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3603	if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3604		port->sysrq_seq = 0;
3605		return false;
3606	}
3607
3608	if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3609		port->sysrq = jiffies + SYSRQ_TIMEOUT;
3610		return true;
3611	}
3612
3613	schedule_work(&sysrq_enable_work);
3614
3615	port->sysrq = 0;
3616	return true;
3617}
3618EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3619#endif
3620
3621/**
3622 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3623 * @port: uart device's target port
3624 *
3625 * This function implements the device tree binding described in
3626 * Documentation/devicetree/bindings/serial/rs485.txt.
3627 */
3628int uart_get_rs485_mode(struct uart_port *port)
3629{
3630	struct serial_rs485 *rs485conf = &port->rs485;
3631	struct device *dev = port->dev;
3632	enum gpiod_flags dflags;
3633	struct gpio_desc *desc;
3634	u32 rs485_delay[2];
3635	int ret;
3636
3637	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
3638		return 0;
3639
3640	ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3641					     rs485_delay, 2);
3642	if (!ret) {
3643		rs485conf->delay_rts_before_send = rs485_delay[0];
3644		rs485conf->delay_rts_after_send = rs485_delay[1];
3645	} else {
3646		rs485conf->delay_rts_before_send = 0;
3647		rs485conf->delay_rts_after_send = 0;
3648	}
3649
3650	uart_sanitize_serial_rs485_delays(port, rs485conf);
3651
3652	/*
3653	 * Clear full-duplex and enabled flags, set RTS polarity to active high
3654	 * to get to a defined state with the following properties:
3655	 */
3656	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3657			      SER_RS485_TERMINATE_BUS |
3658			      SER_RS485_RTS_AFTER_SEND);
3659	rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3660
3661	if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3662		rs485conf->flags |= SER_RS485_RX_DURING_TX;
3663
3664	if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3665		rs485conf->flags |= SER_RS485_ENABLED;
3666
3667	if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3668		rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3669		rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3670	}
3671
3672	/*
3673	 * Disabling termination by default is the safe choice:  Else if many
3674	 * bus participants enable it, no communication is possible at all.
3675	 * Works fine for short cables and users may enable for longer cables.
3676	 */
3677	desc = devm_gpiod_get_optional(dev, "rs485-term", GPIOD_OUT_LOW);
3678	if (IS_ERR(desc))
3679		return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-term-gpios\n");
3680	port->rs485_term_gpio = desc;
3681	if (port->rs485_term_gpio)
3682		port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3683
3684	dflags = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3685		 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3686	desc = devm_gpiod_get_optional(dev, "rs485-rx-during-tx", dflags);
3687	if (IS_ERR(desc))
3688		return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");
3689	port->rs485_rx_during_tx_gpio = desc;
3690	if (port->rs485_rx_during_tx_gpio)
3691		port->rs485_supported.flags |= SER_RS485_RX_DURING_TX;
3692
3693	return 0;
3694}
3695EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3696
3697/* Compile-time assertions for serial_rs485 layout */
3698static_assert(offsetof(struct serial_rs485, padding) ==
3699              (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3700static_assert(offsetof(struct serial_rs485, padding1) ==
3701	      offsetof(struct serial_rs485, padding[1]));
3702static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3703	      sizeof(struct serial_rs485));
3704
3705MODULE_DESCRIPTION("Serial driver core");
3706MODULE_LICENSE("GPL");