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