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