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/of.h>
  19#include <linux/proc_fs.h>
  20#include <linux/seq_file.h>
  21#include <linux/device.h>
  22#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
  23#include <linux/serial_core.h>
  24#include <linux/sysrq.h>
  25#include <linux/delay.h>
  26#include <linux/mutex.h>
  27#include <linux/security.h>
  28
  29#include <linux/irq.h>
  30#include <linux/uaccess.h>
  31
  32/*
  33 * This is used to lock changes in serial line configuration.
  34 */
  35static DEFINE_MUTEX(port_mutex);
  36
  37/*
  38 * lockdep: port->lock is initialized in two places, but we
  39 *          want only one lock-class:
  40 */
  41static struct lock_class_key port_lock_key;
  42
  43#define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)
  44
  45static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
  46					struct ktermios *old_termios);
  47static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
  48static void uart_change_pm(struct uart_state *state,
  49			   enum uart_pm_state pm_state);
  50
  51static void uart_port_shutdown(struct tty_port *port);
  52
  53static int uart_dcd_enabled(struct uart_port *uport)
  54{
  55	return !!(uport->status & UPSTAT_DCD_ENABLE);
  56}
  57
  58static inline struct uart_port *uart_port_ref(struct uart_state *state)
  59{
  60	if (atomic_add_unless(&state->refcount, 1, 0))
  61		return state->uart_port;
  62	return NULL;
  63}
  64
  65static inline void uart_port_deref(struct uart_port *uport)
  66{
  67	if (atomic_dec_and_test(&uport->state->refcount))
  68		wake_up(&uport->state->remove_wait);
  69}
  70
  71#define uart_port_lock(state, flags)					\
  72	({								\
  73		struct uart_port *__uport = uart_port_ref(state);	\
  74		if (__uport)						\
  75			spin_lock_irqsave(&__uport->lock, flags);	\
  76		__uport;						\
  77	})
  78
  79#define uart_port_unlock(uport, flags)					\
  80	({								\
  81		struct uart_port *__uport = uport;			\
  82		if (__uport) {						\
  83			spin_unlock_irqrestore(&__uport->lock, flags);	\
  84			uart_port_deref(__uport);			\
  85		}							\
  86	})
  87
  88static inline struct uart_port *uart_port_check(struct uart_state *state)
  89{
  90	lockdep_assert_held(&state->port.mutex);
  91	return state->uart_port;
  92}
  93
  94/*
  95 * This routine is used by the interrupt handler to schedule processing in
  96 * the software interrupt portion of the driver.
  97 */
  98void uart_write_wakeup(struct uart_port *port)
  99{
 100	struct uart_state *state = port->state;
 101	/*
 102	 * This means you called this function _after_ the port was
 103	 * closed.  No cookie for you.
 104	 */
 105	BUG_ON(!state);
 106	tty_port_tty_wakeup(&state->port);
 107}
 108
 109static void uart_stop(struct tty_struct *tty)
 110{
 111	struct uart_state *state = tty->driver_data;
 112	struct uart_port *port;
 113	unsigned long flags;
 114
 115	port = uart_port_lock(state, flags);
 116	if (port)
 117		port->ops->stop_tx(port);
 118	uart_port_unlock(port, flags);
 119}
 120
 121static void __uart_start(struct tty_struct *tty)
 122{
 123	struct uart_state *state = tty->driver_data;
 124	struct uart_port *port = state->uart_port;
 125
 126	if (port && !uart_tx_stopped(port))
 127		port->ops->start_tx(port);
 128}
 129
 130static void uart_start(struct tty_struct *tty)
 131{
 132	struct uart_state *state = tty->driver_data;
 133	struct uart_port *port;
 134	unsigned long flags;
 135
 136	port = uart_port_lock(state, flags);
 137	__uart_start(tty);
 138	uart_port_unlock(port, flags);
 139}
 140
 141static void
 142uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
 143{
 144	unsigned long flags;
 145	unsigned int old;
 146
 147	spin_lock_irqsave(&port->lock, flags);
 148	old = port->mctrl;
 149	port->mctrl = (old & ~clear) | set;
 150	if (old != port->mctrl)
 151		port->ops->set_mctrl(port, port->mctrl);
 152	spin_unlock_irqrestore(&port->lock, flags);
 153}
 154
 155#define uart_set_mctrl(port, set)	uart_update_mctrl(port, set, 0)
 156#define uart_clear_mctrl(port, clear)	uart_update_mctrl(port, 0, clear)
 157
 158static void uart_port_dtr_rts(struct uart_port *uport, int raise)
 159{
 160	int rs485_on = uport->rs485_config &&
 161		(uport->rs485.flags & SER_RS485_ENABLED);
 162	int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
 163
 164	if (raise) {
 165		if (rs485_on && !RTS_after_send) {
 166			uart_set_mctrl(uport, TIOCM_DTR);
 167			uart_clear_mctrl(uport, TIOCM_RTS);
 168		} else {
 169			uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
 170		}
 171	} else {
 172		unsigned int clear = TIOCM_DTR;
 173
 174		clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
 175		uart_clear_mctrl(uport, clear);
 176	}
 177}
 178
 179/*
 180 * Startup the port.  This will be called once per open.  All calls
 181 * will be serialised by the per-port mutex.
 182 */
 183static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 184		int init_hw)
 185{
 186	struct uart_port *uport = uart_port_check(state);
 187	unsigned long page;
 188	unsigned long flags = 0;
 189	int retval = 0;
 190
 191	if (uport->type == PORT_UNKNOWN)
 192		return 1;
 193
 194	/*
 195	 * Make sure the device is in D0 state.
 196	 */
 197	uart_change_pm(state, UART_PM_STATE_ON);
 198
 199	/*
 200	 * Initialise and allocate the transmit and temporary
 201	 * buffer.
 202	 */
 203	page = get_zeroed_page(GFP_KERNEL);
 204	if (!page)
 205		return -ENOMEM;
 206
 207	uart_port_lock(state, flags);
 208	if (!state->xmit.buf) {
 
 
 
 
 
 209		state->xmit.buf = (unsigned char *) page;
 210		uart_circ_clear(&state->xmit);
 211		uart_port_unlock(uport, flags);
 212	} else {
 213		uart_port_unlock(uport, flags);
 214		/*
 215		 * Do not free() the page under the port lock, see
 216		 * uart_shutdown().
 217		 */
 218		free_page(page);
 219	}
 220
 221	retval = uport->ops->startup(uport);
 222	if (retval == 0) {
 223		if (uart_console(uport) && uport->cons->cflag) {
 224			tty->termios.c_cflag = uport->cons->cflag;
 225			uport->cons->cflag = 0;
 226		}
 227		/*
 228		 * Initialise the hardware port settings.
 229		 */
 230		uart_change_speed(tty, state, NULL);
 231
 232		/*
 233		 * Setup the RTS and DTR signals once the
 234		 * port is open and ready to respond.
 235		 */
 236		if (init_hw && C_BAUD(tty))
 237			uart_port_dtr_rts(uport, 1);
 238	}
 239
 240	/*
 241	 * This is to allow setserial on this port. People may want to set
 242	 * port/irq/type and then reconfigure the port properly if it failed
 243	 * now.
 244	 */
 245	if (retval && capable(CAP_SYS_ADMIN))
 246		return 1;
 247
 248	return retval;
 249}
 250
 251static int uart_startup(struct tty_struct *tty, struct uart_state *state,
 252		int init_hw)
 253{
 254	struct tty_port *port = &state->port;
 255	int retval;
 256
 257	if (tty_port_initialized(port))
 258		return 0;
 259
 260	retval = uart_port_startup(tty, state, init_hw);
 261	if (retval)
 262		set_bit(TTY_IO_ERROR, &tty->flags);
 263
 264	return retval;
 265}
 266
 267/*
 268 * This routine will shutdown a serial port; interrupts are disabled, and
 269 * DTR is dropped if the hangup on close termio flag is on.  Calls to
 270 * uart_shutdown are serialised by the per-port semaphore.
 271 *
 272 * uport == NULL if uart_port has already been removed
 273 */
 274static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 275{
 276	struct uart_port *uport = uart_port_check(state);
 277	struct tty_port *port = &state->port;
 278	unsigned long flags = 0;
 279	char *xmit_buf = NULL;
 280
 281	/*
 282	 * Set the TTY IO error marker
 283	 */
 284	if (tty)
 285		set_bit(TTY_IO_ERROR, &tty->flags);
 286
 287	if (tty_port_initialized(port)) {
 288		tty_port_set_initialized(port, 0);
 289
 290		/*
 291		 * Turn off DTR and RTS early.
 292		 */
 293		if (uport && uart_console(uport) && tty)
 294			uport->cons->cflag = tty->termios.c_cflag;
 295
 296		if (!tty || C_HUPCL(tty))
 297			uart_port_dtr_rts(uport, 0);
 298
 299		uart_port_shutdown(port);
 300	}
 301
 302	/*
 303	 * It's possible for shutdown to be called after suspend if we get
 304	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
 305	 * we don't try to resume a port that has been shutdown.
 306	 */
 307	tty_port_set_suspended(port, 0);
 308
 309	/*
 310	 * Do not free() the transmit buffer page under the port lock since
 311	 * this can create various circular locking scenarios. For instance,
 312	 * console driver may need to allocate/free a debug object, which
 313	 * can endup in printk() recursion.
 314	 */
 315	uart_port_lock(state, flags);
 316	xmit_buf = state->xmit.buf;
 317	state->xmit.buf = NULL;
 318	uart_port_unlock(uport, flags);
 319
 320	if (xmit_buf)
 321		free_page((unsigned long)xmit_buf);
 322}
 323
 324/**
 325 *	uart_update_timeout - update per-port FIFO timeout.
 326 *	@port:  uart_port structure describing the port
 327 *	@cflag: termios cflag value
 328 *	@baud:  speed of the port
 329 *
 330 *	Set the port FIFO timeout value.  The @cflag value should
 331 *	reflect the actual hardware settings.
 332 */
 333void
 334uart_update_timeout(struct uart_port *port, unsigned int cflag,
 335		    unsigned int baud)
 336{
 337	unsigned int bits;
 338
 339	/* byte size and parity */
 340	switch (cflag & CSIZE) {
 341	case CS5:
 342		bits = 7;
 343		break;
 344	case CS6:
 345		bits = 8;
 346		break;
 347	case CS7:
 348		bits = 9;
 349		break;
 350	default:
 351		bits = 10;
 352		break; /* CS8 */
 353	}
 354
 355	if (cflag & CSTOPB)
 356		bits++;
 357	if (cflag & PARENB)
 358		bits++;
 359
 360	/*
 361	 * The total number of bits to be transmitted in the fifo.
 362	 */
 363	bits = bits * port->fifosize;
 364
 365	/*
 366	 * Figure the timeout to send the above number of bits.
 367	 * Add .02 seconds of slop
 368	 */
 369	port->timeout = (HZ * bits) / baud + HZ/50;
 370}
 371
 372EXPORT_SYMBOL(uart_update_timeout);
 373
 374/**
 375 *	uart_get_baud_rate - return baud rate for a particular port
 376 *	@port: uart_port structure describing the port in question.
 377 *	@termios: desired termios settings.
 378 *	@old: old termios (or NULL)
 379 *	@min: minimum acceptable baud rate
 380 *	@max: maximum acceptable baud rate
 381 *
 382 *	Decode the termios structure into a numeric baud rate,
 383 *	taking account of the magic 38400 baud rate (with spd_*
 384 *	flags), and mapping the %B0 rate to 9600 baud.
 385 *
 386 *	If the new baud rate is invalid, try the old termios setting.
 387 *	If it's still invalid, we try 9600 baud.
 388 *
 389 *	Update the @termios structure to reflect the baud rate
 390 *	we're actually going to be using. Don't do this for the case
 391 *	where B0 is requested ("hang up").
 392 */
 393unsigned int
 394uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 395		   struct ktermios *old, unsigned int min, unsigned int max)
 396{
 397	unsigned int try;
 398	unsigned int baud;
 399	unsigned int altbaud;
 400	int hung_up = 0;
 401	upf_t flags = port->flags & UPF_SPD_MASK;
 402
 403	switch (flags) {
 404	case UPF_SPD_HI:
 405		altbaud = 57600;
 406		break;
 407	case UPF_SPD_VHI:
 408		altbaud = 115200;
 409		break;
 410	case UPF_SPD_SHI:
 411		altbaud = 230400;
 412		break;
 413	case UPF_SPD_WARP:
 414		altbaud = 460800;
 415		break;
 416	default:
 417		altbaud = 38400;
 418		break;
 419	}
 420
 421	for (try = 0; try < 2; try++) {
 422		baud = tty_termios_baud_rate(termios);
 423
 424		/*
 425		 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
 426		 * Die! Die! Die!
 427		 */
 428		if (try == 0 && baud == 38400)
 429			baud = altbaud;
 430
 431		/*
 432		 * Special case: B0 rate.
 433		 */
 434		if (baud == 0) {
 435			hung_up = 1;
 436			baud = 9600;
 437		}
 438
 439		if (baud >= min && baud <= max)
 440			return baud;
 441
 442		/*
 443		 * Oops, the quotient was zero.  Try again with
 444		 * the old baud rate if possible.
 445		 */
 446		termios->c_cflag &= ~CBAUD;
 447		if (old) {
 448			baud = tty_termios_baud_rate(old);
 449			if (!hung_up)
 450				tty_termios_encode_baud_rate(termios,
 451								baud, baud);
 452			old = NULL;
 453			continue;
 454		}
 455
 456		/*
 457		 * As a last resort, if the range cannot be met then clip to
 458		 * the nearest chip supported rate.
 459		 */
 460		if (!hung_up) {
 461			if (baud <= min)
 462				tty_termios_encode_baud_rate(termios,
 463							min + 1, min + 1);
 464			else
 465				tty_termios_encode_baud_rate(termios,
 466							max - 1, max - 1);
 467		}
 468	}
 469	/* Should never happen */
 470	WARN_ON(1);
 471	return 0;
 472}
 473
 474EXPORT_SYMBOL(uart_get_baud_rate);
 475
 476/**
 477 *	uart_get_divisor - return uart clock divisor
 478 *	@port: uart_port structure describing the port.
 479 *	@baud: desired baud rate
 480 *
 481 *	Calculate the uart clock divisor for the port.
 482 */
 483unsigned int
 484uart_get_divisor(struct uart_port *port, unsigned int baud)
 485{
 486	unsigned int quot;
 487
 488	/*
 489	 * Old custom speed handling.
 490	 */
 491	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
 492		quot = port->custom_divisor;
 493	else
 494		quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
 495
 496	return quot;
 497}
 498
 499EXPORT_SYMBOL(uart_get_divisor);
 500
 501/* Caller holds port mutex */
 502static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
 503					struct ktermios *old_termios)
 504{
 505	struct uart_port *uport = uart_port_check(state);
 506	struct ktermios *termios;
 507	int hw_stopped;
 508
 509	/*
 510	 * If we have no tty, termios, or the port does not exist,
 511	 * then we can't set the parameters for this port.
 512	 */
 513	if (!tty || uport->type == PORT_UNKNOWN)
 514		return;
 515
 516	termios = &tty->termios;
 517	uport->ops->set_termios(uport, termios, old_termios);
 518
 519	/*
 520	 * Set modem status enables based on termios cflag
 521	 */
 522	spin_lock_irq(&uport->lock);
 523	if (termios->c_cflag & CRTSCTS)
 524		uport->status |= UPSTAT_CTS_ENABLE;
 525	else
 526		uport->status &= ~UPSTAT_CTS_ENABLE;
 527
 528	if (termios->c_cflag & CLOCAL)
 529		uport->status &= ~UPSTAT_DCD_ENABLE;
 530	else
 531		uport->status |= UPSTAT_DCD_ENABLE;
 532
 533	/* reset sw-assisted CTS flow control based on (possibly) new mode */
 534	hw_stopped = uport->hw_stopped;
 535	uport->hw_stopped = uart_softcts_mode(uport) &&
 536				!(uport->ops->get_mctrl(uport) & TIOCM_CTS);
 537	if (uport->hw_stopped) {
 538		if (!hw_stopped)
 539			uport->ops->stop_tx(uport);
 540	} else {
 541		if (hw_stopped)
 542			__uart_start(tty);
 543	}
 544	spin_unlock_irq(&uport->lock);
 545}
 546
 547static int uart_put_char(struct tty_struct *tty, unsigned char c)
 548{
 549	struct uart_state *state = tty->driver_data;
 550	struct uart_port *port;
 551	struct circ_buf *circ;
 552	unsigned long flags;
 553	int ret = 0;
 554
 555	circ = &state->xmit;
 556	port = uart_port_lock(state, flags);
 557	if (!circ->buf) {
 558		uart_port_unlock(port, flags);
 559		return 0;
 560	}
 561
 
 562	if (port && uart_circ_chars_free(circ) != 0) {
 563		circ->buf[circ->head] = c;
 564		circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
 565		ret = 1;
 566	}
 567	uart_port_unlock(port, flags);
 568	return ret;
 569}
 570
 571static void uart_flush_chars(struct tty_struct *tty)
 572{
 573	uart_start(tty);
 574}
 575
 576static int uart_write(struct tty_struct *tty,
 577					const unsigned char *buf, int count)
 578{
 579	struct uart_state *state = tty->driver_data;
 580	struct uart_port *port;
 581	struct circ_buf *circ;
 582	unsigned long flags;
 583	int c, ret = 0;
 584
 585	/*
 586	 * This means you called this function _after_ the port was
 587	 * closed.  No cookie for you.
 588	 */
 589	if (!state) {
 590		WARN_ON(1);
 591		return -EL3HLT;
 592	}
 593
 594	port = uart_port_lock(state, flags);
 595	circ = &state->xmit;
 596	if (!circ->buf) {
 597		uart_port_unlock(port, flags);
 598		return 0;
 599	}
 600
 
 601	while (port) {
 602		c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
 603		if (count < c)
 604			c = count;
 605		if (c <= 0)
 606			break;
 607		memcpy(circ->buf + circ->head, buf, c);
 608		circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
 609		buf += c;
 610		count -= c;
 611		ret += c;
 612	}
 613
 614	__uart_start(tty);
 615	uart_port_unlock(port, flags);
 616	return ret;
 617}
 618
 619static int uart_write_room(struct tty_struct *tty)
 620{
 621	struct uart_state *state = tty->driver_data;
 622	struct uart_port *port;
 623	unsigned long flags;
 624	int ret;
 625
 626	port = uart_port_lock(state, flags);
 627	ret = uart_circ_chars_free(&state->xmit);
 628	uart_port_unlock(port, flags);
 629	return ret;
 630}
 631
 632static int uart_chars_in_buffer(struct tty_struct *tty)
 633{
 634	struct uart_state *state = tty->driver_data;
 635	struct uart_port *port;
 636	unsigned long flags;
 637	int ret;
 638
 639	port = uart_port_lock(state, flags);
 640	ret = uart_circ_chars_pending(&state->xmit);
 641	uart_port_unlock(port, flags);
 642	return ret;
 643}
 644
 645static void uart_flush_buffer(struct tty_struct *tty)
 646{
 647	struct uart_state *state = tty->driver_data;
 648	struct uart_port *port;
 649	unsigned long flags;
 650
 651	/*
 652	 * This means you called this function _after_ the port was
 653	 * closed.  No cookie for you.
 654	 */
 655	if (!state) {
 656		WARN_ON(1);
 657		return;
 658	}
 659
 660	pr_debug("uart_flush_buffer(%d) called\n", tty->index);
 661
 662	port = uart_port_lock(state, flags);
 663	if (!port)
 664		return;
 665	uart_circ_clear(&state->xmit);
 666	if (port->ops->flush_buffer)
 667		port->ops->flush_buffer(port);
 668	uart_port_unlock(port, flags);
 669	tty_port_tty_wakeup(&state->port);
 670}
 671
 672/*
 673 * This function is used to send a high-priority XON/XOFF character to
 674 * the device
 675 */
 676static void uart_send_xchar(struct tty_struct *tty, char ch)
 677{
 678	struct uart_state *state = tty->driver_data;
 679	struct uart_port *port;
 680	unsigned long flags;
 681
 682	port = uart_port_ref(state);
 683	if (!port)
 684		return;
 685
 686	if (port->ops->send_xchar)
 687		port->ops->send_xchar(port, ch);
 688	else {
 689		spin_lock_irqsave(&port->lock, flags);
 690		port->x_char = ch;
 691		if (ch)
 692			port->ops->start_tx(port);
 693		spin_unlock_irqrestore(&port->lock, flags);
 694	}
 695	uart_port_deref(port);
 696}
 697
 698static void uart_throttle(struct tty_struct *tty)
 699{
 700	struct uart_state *state = tty->driver_data;
 701	upstat_t mask = UPSTAT_SYNC_FIFO;
 702	struct uart_port *port;
 
 703
 704	port = uart_port_ref(state);
 705	if (!port)
 706		return;
 707
 708	if (I_IXOFF(tty))
 709		mask |= UPSTAT_AUTOXOFF;
 710	if (C_CRTSCTS(tty))
 711		mask |= UPSTAT_AUTORTS;
 712
 713	if (port->status & mask) {
 714		port->ops->throttle(port);
 715		mask &= ~port->status;
 716	}
 717
 718	if (mask & UPSTAT_AUTORTS)
 719		uart_clear_mctrl(port, TIOCM_RTS);
 720
 721	if (mask & UPSTAT_AUTOXOFF)
 722		uart_send_xchar(tty, STOP_CHAR(tty));
 723
 724	uart_port_deref(port);
 725}
 726
 727static void uart_unthrottle(struct tty_struct *tty)
 728{
 729	struct uart_state *state = tty->driver_data;
 730	upstat_t mask = UPSTAT_SYNC_FIFO;
 731	struct uart_port *port;
 
 732
 733	port = uart_port_ref(state);
 734	if (!port)
 735		return;
 736
 737	if (I_IXOFF(tty))
 738		mask |= UPSTAT_AUTOXOFF;
 739	if (C_CRTSCTS(tty))
 740		mask |= UPSTAT_AUTORTS;
 741
 742	if (port->status & mask) {
 743		port->ops->unthrottle(port);
 744		mask &= ~port->status;
 745	}
 746
 747	if (mask & UPSTAT_AUTORTS)
 748		uart_set_mctrl(port, TIOCM_RTS);
 749
 750	if (mask & UPSTAT_AUTOXOFF)
 751		uart_send_xchar(tty, START_CHAR(tty));
 752
 753	uart_port_deref(port);
 754}
 755
 756static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
 757{
 758	struct uart_state *state = container_of(port, struct uart_state, port);
 759	struct uart_port *uport;
 760	int ret = -ENODEV;
 761
 762	memset(retinfo, 0, sizeof(*retinfo));
 763
 764	/*
 765	 * Ensure the state we copy is consistent and no hardware changes
 766	 * occur as we go
 767	 */
 768	mutex_lock(&port->mutex);
 769	uport = uart_port_check(state);
 770	if (!uport)
 771		goto out;
 772
 773	retinfo->type	    = uport->type;
 774	retinfo->line	    = uport->line;
 775	retinfo->port	    = uport->iobase;
 776	if (HIGH_BITS_OFFSET)
 777		retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
 778	retinfo->irq		    = uport->irq;
 779	retinfo->flags	    = (__force int)uport->flags;
 780	retinfo->xmit_fifo_size  = uport->fifosize;
 781	retinfo->baud_base	    = uport->uartclk / 16;
 782	retinfo->close_delay	    = jiffies_to_msecs(port->close_delay) / 10;
 783	retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 784				ASYNC_CLOSING_WAIT_NONE :
 785				jiffies_to_msecs(port->closing_wait) / 10;
 786	retinfo->custom_divisor  = uport->custom_divisor;
 787	retinfo->hub6	    = uport->hub6;
 788	retinfo->io_type         = uport->iotype;
 789	retinfo->iomem_reg_shift = uport->regshift;
 790	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
 791
 792	ret = 0;
 793out:
 794	mutex_unlock(&port->mutex);
 795	return ret;
 796}
 797
 798static int uart_get_info_user(struct tty_struct *tty,
 799			 struct serial_struct *ss)
 800{
 801	struct uart_state *state = tty->driver_data;
 802	struct tty_port *port = &state->port;
 
 
 803
 804	return uart_get_info(port, ss) < 0 ? -EIO : 0;
 
 
 805}
 806
 807static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 808			 struct uart_state *state,
 809			 struct serial_struct *new_info)
 810{
 811	struct uart_port *uport = uart_port_check(state);
 812	unsigned long new_port;
 813	unsigned int change_irq, change_port, closing_wait;
 814	unsigned int old_custom_divisor, close_delay;
 815	upf_t old_flags, new_flags;
 816	int retval = 0;
 817
 818	if (!uport)
 819		return -EIO;
 820
 821	new_port = new_info->port;
 822	if (HIGH_BITS_OFFSET)
 823		new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
 824
 825	new_info->irq = irq_canonicalize(new_info->irq);
 826	close_delay = msecs_to_jiffies(new_info->close_delay * 10);
 827	closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 828			ASYNC_CLOSING_WAIT_NONE :
 829			msecs_to_jiffies(new_info->closing_wait * 10);
 830
 831
 832	change_irq  = !(uport->flags & UPF_FIXED_PORT)
 833		&& new_info->irq != uport->irq;
 834
 835	/*
 836	 * Since changing the 'type' of the port changes its resource
 837	 * allocations, we should treat type changes the same as
 838	 * IO port changes.
 839	 */
 840	change_port = !(uport->flags & UPF_FIXED_PORT)
 841		&& (new_port != uport->iobase ||
 842		    (unsigned long)new_info->iomem_base != uport->mapbase ||
 843		    new_info->hub6 != uport->hub6 ||
 844		    new_info->io_type != uport->iotype ||
 845		    new_info->iomem_reg_shift != uport->regshift ||
 846		    new_info->type != uport->type);
 847
 848	old_flags = uport->flags;
 849	new_flags = (__force upf_t)new_info->flags;
 850	old_custom_divisor = uport->custom_divisor;
 851
 852	if (!capable(CAP_SYS_ADMIN)) {
 853		retval = -EPERM;
 854		if (change_irq || change_port ||
 855		    (new_info->baud_base != uport->uartclk / 16) ||
 856		    (close_delay != port->close_delay) ||
 857		    (closing_wait != port->closing_wait) ||
 858		    (new_info->xmit_fifo_size &&
 859		     new_info->xmit_fifo_size != uport->fifosize) ||
 860		    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
 861			goto exit;
 862		uport->flags = ((uport->flags & ~UPF_USR_MASK) |
 863			       (new_flags & UPF_USR_MASK));
 864		uport->custom_divisor = new_info->custom_divisor;
 865		goto check_and_exit;
 866	}
 867
 868	retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
 869	if (retval && (change_irq || change_port))
 870		goto exit;
 871
 872	/*
 873	 * Ask the low level driver to verify the settings.
 874	 */
 875	if (uport->ops->verify_port)
 876		retval = uport->ops->verify_port(uport, new_info);
 877
 878	if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
 879	    (new_info->baud_base < 9600))
 880		retval = -EINVAL;
 881
 882	if (retval)
 883		goto exit;
 884
 885	if (change_port || change_irq) {
 886		retval = -EBUSY;
 887
 888		/*
 889		 * Make sure that we are the sole user of this port.
 890		 */
 891		if (tty_port_users(port) > 1)
 892			goto exit;
 893
 894		/*
 895		 * We need to shutdown the serial port at the old
 896		 * port/type/irq combination.
 897		 */
 898		uart_shutdown(tty, state);
 899	}
 900
 901	if (change_port) {
 902		unsigned long old_iobase, old_mapbase;
 903		unsigned int old_type, old_iotype, old_hub6, old_shift;
 904
 905		old_iobase = uport->iobase;
 906		old_mapbase = uport->mapbase;
 907		old_type = uport->type;
 908		old_hub6 = uport->hub6;
 909		old_iotype = uport->iotype;
 910		old_shift = uport->regshift;
 911
 912		/*
 913		 * Free and release old regions
 914		 */
 915		if (old_type != PORT_UNKNOWN && uport->ops->release_port)
 916			uport->ops->release_port(uport);
 917
 918		uport->iobase = new_port;
 919		uport->type = new_info->type;
 920		uport->hub6 = new_info->hub6;
 921		uport->iotype = new_info->io_type;
 922		uport->regshift = new_info->iomem_reg_shift;
 923		uport->mapbase = (unsigned long)new_info->iomem_base;
 924
 925		/*
 926		 * Claim and map the new regions
 927		 */
 928		if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
 929			retval = uport->ops->request_port(uport);
 930		} else {
 931			/* Always success - Jean II */
 932			retval = 0;
 933		}
 934
 935		/*
 936		 * If we fail to request resources for the
 937		 * new port, try to restore the old settings.
 938		 */
 939		if (retval) {
 940			uport->iobase = old_iobase;
 941			uport->type = old_type;
 942			uport->hub6 = old_hub6;
 943			uport->iotype = old_iotype;
 944			uport->regshift = old_shift;
 945			uport->mapbase = old_mapbase;
 946
 947			if (old_type != PORT_UNKNOWN) {
 948				retval = uport->ops->request_port(uport);
 949				/*
 950				 * If we failed to restore the old settings,
 951				 * we fail like this.
 952				 */
 953				if (retval)
 954					uport->type = PORT_UNKNOWN;
 955
 956				/*
 957				 * We failed anyway.
 958				 */
 959				retval = -EBUSY;
 960			}
 961
 962			/* Added to return the correct error -Ram Gupta */
 963			goto exit;
 964		}
 965	}
 966
 967	if (change_irq)
 968		uport->irq      = new_info->irq;
 969	if (!(uport->flags & UPF_FIXED_PORT))
 970		uport->uartclk  = new_info->baud_base * 16;
 971	uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
 972				 (new_flags & UPF_CHANGE_MASK);
 973	uport->custom_divisor   = new_info->custom_divisor;
 974	port->close_delay     = close_delay;
 975	port->closing_wait    = closing_wait;
 976	if (new_info->xmit_fifo_size)
 977		uport->fifosize = new_info->xmit_fifo_size;
 978	port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
 979
 980 check_and_exit:
 981	retval = 0;
 982	if (uport->type == PORT_UNKNOWN)
 983		goto exit;
 984	if (tty_port_initialized(port)) {
 985		if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
 986		    old_custom_divisor != uport->custom_divisor) {
 987			/*
 988			 * If they're setting up a custom divisor or speed,
 989			 * instead of clearing it, then bitch about it.
 990			 */
 991			if (uport->flags & UPF_SPD_MASK) {
 992				dev_notice_ratelimited(uport->dev,
 993				       "%s sets custom speed on %s. This is deprecated.\n",
 994				      current->comm,
 995				      tty_name(port->tty));
 996			}
 997			uart_change_speed(tty, state, NULL);
 998		}
 999	} else {
1000		retval = uart_startup(tty, state, 1);
1001		if (retval == 0)
1002			tty_port_set_initialized(port, true);
1003		if (retval > 0)
1004			retval = 0;
1005	}
1006 exit:
1007	return retval;
1008}
1009
1010static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
 
1011{
1012	struct uart_state *state = tty->driver_data;
1013	struct tty_port *port = &state->port;
1014	int retval;
1015
1016	down_write(&tty->termios_rwsem);
 
 
1017	/*
1018	 * This semaphore protects port->count.  It is also
1019	 * very useful to prevent opens.  Also, take the
1020	 * port configuration semaphore to make sure that a
1021	 * module insertion/removal doesn't change anything
1022	 * under us.
1023	 */
1024	mutex_lock(&port->mutex);
1025	retval = uart_set_info(tty, port, state, ss);
1026	mutex_unlock(&port->mutex);
1027	up_write(&tty->termios_rwsem);
1028	return retval;
1029}
1030
1031/**
1032 *	uart_get_lsr_info	-	get line status register info
1033 *	@tty: tty associated with the UART
1034 *	@state: UART being queried
1035 *	@value: returned modem value
1036 */
1037static int uart_get_lsr_info(struct tty_struct *tty,
1038			struct uart_state *state, unsigned int __user *value)
1039{
1040	struct uart_port *uport = uart_port_check(state);
1041	unsigned int result;
1042
1043	result = uport->ops->tx_empty(uport);
1044
1045	/*
1046	 * If we're about to load something into the transmit
1047	 * register, we'll pretend the transmitter isn't empty to
1048	 * avoid a race condition (depending on when the transmit
1049	 * interrupt happens).
1050	 */
1051	if (uport->x_char ||
1052	    ((uart_circ_chars_pending(&state->xmit) > 0) &&
1053	     !uart_tx_stopped(uport)))
1054		result &= ~TIOCSER_TEMT;
1055
1056	return put_user(result, value);
1057}
1058
1059static int uart_tiocmget(struct tty_struct *tty)
1060{
1061	struct uart_state *state = tty->driver_data;
1062	struct tty_port *port = &state->port;
1063	struct uart_port *uport;
1064	int result = -EIO;
1065
1066	mutex_lock(&port->mutex);
1067	uport = uart_port_check(state);
1068	if (!uport)
1069		goto out;
1070
1071	if (!tty_io_error(tty)) {
1072		result = uport->mctrl;
1073		spin_lock_irq(&uport->lock);
1074		result |= uport->ops->get_mctrl(uport);
1075		spin_unlock_irq(&uport->lock);
1076	}
1077out:
1078	mutex_unlock(&port->mutex);
1079	return result;
1080}
1081
1082static int
1083uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1084{
1085	struct uart_state *state = tty->driver_data;
1086	struct tty_port *port = &state->port;
1087	struct uart_port *uport;
1088	int ret = -EIO;
1089
1090	mutex_lock(&port->mutex);
1091	uport = uart_port_check(state);
1092	if (!uport)
1093		goto out;
1094
1095	if (!tty_io_error(tty)) {
1096		uart_update_mctrl(uport, set, clear);
1097		ret = 0;
1098	}
1099out:
1100	mutex_unlock(&port->mutex);
1101	return ret;
1102}
1103
1104static int uart_break_ctl(struct tty_struct *tty, int break_state)
1105{
1106	struct uart_state *state = tty->driver_data;
1107	struct tty_port *port = &state->port;
1108	struct uart_port *uport;
1109	int ret = -EIO;
1110
1111	mutex_lock(&port->mutex);
1112	uport = uart_port_check(state);
1113	if (!uport)
1114		goto out;
1115
1116	if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1117		uport->ops->break_ctl(uport, break_state);
1118	ret = 0;
1119out:
1120	mutex_unlock(&port->mutex);
1121	return ret;
1122}
1123
1124static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1125{
1126	struct tty_port *port = &state->port;
1127	struct uart_port *uport;
1128	int flags, ret;
1129
1130	if (!capable(CAP_SYS_ADMIN))
1131		return -EPERM;
1132
1133	/*
1134	 * Take the per-port semaphore.  This prevents count from
1135	 * changing, and hence any extra opens of the port while
1136	 * we're auto-configuring.
1137	 */
1138	if (mutex_lock_interruptible(&port->mutex))
1139		return -ERESTARTSYS;
1140
1141	uport = uart_port_check(state);
1142	if (!uport) {
1143		ret = -EIO;
1144		goto out;
1145	}
1146
1147	ret = -EBUSY;
1148	if (tty_port_users(port) == 1) {
1149		uart_shutdown(tty, state);
1150
1151		/*
1152		 * If we already have a port type configured,
1153		 * we must release its resources.
1154		 */
1155		if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1156			uport->ops->release_port(uport);
1157
1158		flags = UART_CONFIG_TYPE;
1159		if (uport->flags & UPF_AUTO_IRQ)
1160			flags |= UART_CONFIG_IRQ;
1161
1162		/*
1163		 * This will claim the ports resources if
1164		 * a port is found.
1165		 */
1166		uport->ops->config_port(uport, flags);
1167
1168		ret = uart_startup(tty, state, 1);
1169		if (ret == 0)
1170			tty_port_set_initialized(port, true);
1171		if (ret > 0)
1172			ret = 0;
1173	}
1174out:
1175	mutex_unlock(&port->mutex);
1176	return ret;
1177}
1178
1179static void uart_enable_ms(struct uart_port *uport)
1180{
1181	/*
1182	 * Force modem status interrupts on
1183	 */
1184	if (uport->ops->enable_ms)
1185		uport->ops->enable_ms(uport);
1186}
1187
1188/*
1189 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1190 * - mask passed in arg for lines of interest
1191 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1192 * Caller should use TIOCGICOUNT to see which one it was
1193 *
1194 * FIXME: This wants extracting into a common all driver implementation
1195 * of TIOCMWAIT using tty_port.
1196 */
1197static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1198{
1199	struct uart_port *uport;
1200	struct tty_port *port = &state->port;
1201	DECLARE_WAITQUEUE(wait, current);
1202	struct uart_icount cprev, cnow;
1203	int ret;
1204
1205	/*
1206	 * note the counters on entry
1207	 */
1208	uport = uart_port_ref(state);
1209	if (!uport)
1210		return -EIO;
1211	spin_lock_irq(&uport->lock);
1212	memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1213	uart_enable_ms(uport);
1214	spin_unlock_irq(&uport->lock);
1215
1216	add_wait_queue(&port->delta_msr_wait, &wait);
1217	for (;;) {
1218		spin_lock_irq(&uport->lock);
1219		memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1220		spin_unlock_irq(&uport->lock);
1221
1222		set_current_state(TASK_INTERRUPTIBLE);
1223
1224		if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1225		    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1226		    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1227		    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1228			ret = 0;
1229			break;
1230		}
1231
1232		schedule();
1233
1234		/* see if a signal did it */
1235		if (signal_pending(current)) {
1236			ret = -ERESTARTSYS;
1237			break;
1238		}
1239
1240		cprev = cnow;
1241	}
1242	__set_current_state(TASK_RUNNING);
1243	remove_wait_queue(&port->delta_msr_wait, &wait);
1244	uart_port_deref(uport);
1245
1246	return ret;
1247}
1248
1249/*
1250 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1251 * Return: write counters to the user passed counter struct
1252 * NB: both 1->0 and 0->1 transitions are counted except for
1253 *     RI where only 0->1 is counted.
1254 */
1255static int uart_get_icount(struct tty_struct *tty,
1256			  struct serial_icounter_struct *icount)
1257{
1258	struct uart_state *state = tty->driver_data;
1259	struct uart_icount cnow;
1260	struct uart_port *uport;
1261
1262	uport = uart_port_ref(state);
1263	if (!uport)
1264		return -EIO;
1265	spin_lock_irq(&uport->lock);
1266	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1267	spin_unlock_irq(&uport->lock);
1268	uart_port_deref(uport);
1269
1270	icount->cts         = cnow.cts;
1271	icount->dsr         = cnow.dsr;
1272	icount->rng         = cnow.rng;
1273	icount->dcd         = cnow.dcd;
1274	icount->rx          = cnow.rx;
1275	icount->tx          = cnow.tx;
1276	icount->frame       = cnow.frame;
1277	icount->overrun     = cnow.overrun;
1278	icount->parity      = cnow.parity;
1279	icount->brk         = cnow.brk;
1280	icount->buf_overrun = cnow.buf_overrun;
1281
1282	return 0;
1283}
1284
1285static int uart_get_rs485_config(struct uart_port *port,
1286			 struct serial_rs485 __user *rs485)
1287{
1288	unsigned long flags;
1289	struct serial_rs485 aux;
1290
1291	spin_lock_irqsave(&port->lock, flags);
1292	aux = port->rs485;
1293	spin_unlock_irqrestore(&port->lock, flags);
1294
1295	if (copy_to_user(rs485, &aux, sizeof(aux)))
1296		return -EFAULT;
1297
1298	return 0;
1299}
1300
1301static int uart_set_rs485_config(struct uart_port *port,
1302			 struct serial_rs485 __user *rs485_user)
1303{
1304	struct serial_rs485 rs485;
1305	int ret;
1306	unsigned long flags;
1307
1308	if (!port->rs485_config)
1309		return -ENOIOCTLCMD;
1310
1311	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1312		return -EFAULT;
1313
1314	spin_lock_irqsave(&port->lock, flags);
1315	ret = port->rs485_config(port, &rs485);
1316	spin_unlock_irqrestore(&port->lock, flags);
1317	if (ret)
1318		return ret;
1319
1320	if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1321		return -EFAULT;
1322
1323	return 0;
1324}
1325
1326static int uart_get_iso7816_config(struct uart_port *port,
1327				   struct serial_iso7816 __user *iso7816)
1328{
1329	unsigned long flags;
1330	struct serial_iso7816 aux;
1331
1332	if (!port->iso7816_config)
1333		return -ENOIOCTLCMD;
1334
1335	spin_lock_irqsave(&port->lock, flags);
1336	aux = port->iso7816;
1337	spin_unlock_irqrestore(&port->lock, flags);
1338
1339	if (copy_to_user(iso7816, &aux, sizeof(aux)))
1340		return -EFAULT;
1341
1342	return 0;
1343}
1344
1345static int uart_set_iso7816_config(struct uart_port *port,
1346				   struct serial_iso7816 __user *iso7816_user)
1347{
1348	struct serial_iso7816 iso7816;
1349	int i, ret;
1350	unsigned long flags;
1351
1352	if (!port->iso7816_config)
1353		return -ENOIOCTLCMD;
1354
1355	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1356		return -EFAULT;
1357
1358	/*
1359	 * There are 5 words reserved for future use. Check that userspace
1360	 * doesn't put stuff in there to prevent breakages in the future.
1361	 */
1362	for (i = 0; i < 5; i++)
1363		if (iso7816.reserved[i])
1364			return -EINVAL;
1365
1366	spin_lock_irqsave(&port->lock, flags);
1367	ret = port->iso7816_config(port, &iso7816);
1368	spin_unlock_irqrestore(&port->lock, flags);
1369	if (ret)
1370		return ret;
1371
1372	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1373		return -EFAULT;
1374
1375	return 0;
1376}
1377
1378/*
1379 * Called via sys_ioctl.  We can use spin_lock_irq() here.
1380 */
1381static int
1382uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1383{
1384	struct uart_state *state = tty->driver_data;
1385	struct tty_port *port = &state->port;
1386	struct uart_port *uport;
1387	void __user *uarg = (void __user *)arg;
1388	int ret = -ENOIOCTLCMD;
1389
1390
1391	/*
1392	 * These ioctls don't rely on the hardware to be present.
1393	 */
1394	switch (cmd) {
 
 
 
 
 
 
 
 
 
 
1395	case TIOCSERCONFIG:
1396		down_write(&tty->termios_rwsem);
1397		ret = uart_do_autoconfig(tty, state);
1398		up_write(&tty->termios_rwsem);
1399		break;
 
 
 
 
 
1400	}
1401
1402	if (ret != -ENOIOCTLCMD)
1403		goto out;
1404
1405	if (tty_io_error(tty)) {
1406		ret = -EIO;
1407		goto out;
1408	}
1409
1410	/*
1411	 * The following should only be used when hardware is present.
1412	 */
1413	switch (cmd) {
1414	case TIOCMIWAIT:
1415		ret = uart_wait_modem_status(state, arg);
1416		break;
1417	}
1418
1419	if (ret != -ENOIOCTLCMD)
1420		goto out;
1421
1422	mutex_lock(&port->mutex);
1423	uport = uart_port_check(state);
1424
1425	if (!uport || tty_io_error(tty)) {
1426		ret = -EIO;
1427		goto out_up;
1428	}
1429
1430	/*
1431	 * All these rely on hardware being present and need to be
1432	 * protected against the tty being hung up.
1433	 */
1434
1435	switch (cmd) {
1436	case TIOCSERGETLSR: /* Get line status register */
1437		ret = uart_get_lsr_info(tty, state, uarg);
1438		break;
1439
1440	case TIOCGRS485:
1441		ret = uart_get_rs485_config(uport, uarg);
1442		break;
1443
1444	case TIOCSRS485:
1445		ret = uart_set_rs485_config(uport, uarg);
1446		break;
1447
1448	case TIOCSISO7816:
1449		ret = uart_set_iso7816_config(state->uart_port, uarg);
1450		break;
1451
1452	case TIOCGISO7816:
1453		ret = uart_get_iso7816_config(state->uart_port, uarg);
1454		break;
1455	default:
1456		if (uport->ops->ioctl)
1457			ret = uport->ops->ioctl(uport, cmd, arg);
1458		break;
1459	}
1460out_up:
1461	mutex_unlock(&port->mutex);
1462out:
1463	return ret;
1464}
1465
1466static void uart_set_ldisc(struct tty_struct *tty)
1467{
1468	struct uart_state *state = tty->driver_data;
1469	struct uart_port *uport;
1470
1471	mutex_lock(&state->port.mutex);
1472	uport = uart_port_check(state);
1473	if (uport && uport->ops->set_ldisc)
1474		uport->ops->set_ldisc(uport, &tty->termios);
1475	mutex_unlock(&state->port.mutex);
1476}
1477
1478static void uart_set_termios(struct tty_struct *tty,
1479						struct ktermios *old_termios)
1480{
1481	struct uart_state *state = tty->driver_data;
1482	struct uart_port *uport;
1483	unsigned int cflag = tty->termios.c_cflag;
1484	unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1485	bool sw_changed = false;
1486
1487	mutex_lock(&state->port.mutex);
1488	uport = uart_port_check(state);
1489	if (!uport)
1490		goto out;
1491
1492	/*
1493	 * Drivers doing software flow control also need to know
1494	 * about changes to these input settings.
1495	 */
1496	if (uport->flags & UPF_SOFT_FLOW) {
1497		iflag_mask |= IXANY|IXON|IXOFF;
1498		sw_changed =
1499		   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1500		   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1501	}
1502
1503	/*
1504	 * These are the bits that are used to setup various
1505	 * flags in the low level driver. We can ignore the Bfoo
1506	 * bits in c_cflag; c_[io]speed will always be set
1507	 * appropriately by set_termios() in tty_ioctl.c
1508	 */
1509	if ((cflag ^ old_termios->c_cflag) == 0 &&
1510	    tty->termios.c_ospeed == old_termios->c_ospeed &&
1511	    tty->termios.c_ispeed == old_termios->c_ispeed &&
1512	    ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1513	    !sw_changed) {
1514		goto out;
1515	}
1516
1517	uart_change_speed(tty, state, old_termios);
1518	/* reload cflag from termios; port driver may have overridden flags */
1519	cflag = tty->termios.c_cflag;
1520
1521	/* Handle transition to B0 status */
1522	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1523		uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1524	/* Handle transition away from B0 status */
1525	else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1526		unsigned int mask = TIOCM_DTR;
1527
1528		if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1529			mask |= TIOCM_RTS;
1530		uart_set_mctrl(uport, mask);
1531	}
1532out:
1533	mutex_unlock(&state->port.mutex);
1534}
1535
1536/*
1537 * Calls to uart_close() are serialised via the tty_lock in
1538 *   drivers/tty/tty_io.c:tty_release()
1539 *   drivers/tty/tty_io.c:do_tty_hangup()
1540 */
1541static void uart_close(struct tty_struct *tty, struct file *filp)
1542{
1543	struct uart_state *state = tty->driver_data;
1544
1545	if (!state) {
1546		struct uart_driver *drv = tty->driver->driver_state;
1547		struct tty_port *port;
1548
1549		state = drv->state + tty->index;
1550		port = &state->port;
1551		spin_lock_irq(&port->lock);
1552		--port->count;
1553		spin_unlock_irq(&port->lock);
1554		return;
1555	}
1556
1557	pr_debug("uart_close(%d) called\n", tty->index);
1558
1559	tty_port_close(tty->port, tty, filp);
1560}
1561
1562static void uart_tty_port_shutdown(struct tty_port *port)
1563{
1564	struct uart_state *state = container_of(port, struct uart_state, port);
1565	struct uart_port *uport = uart_port_check(state);
1566
1567	/*
1568	 * At this point, we stop accepting input.  To do this, we
1569	 * disable the receive line status interrupts.
1570	 */
1571	if (WARN(!uport, "detached port still initialized!\n"))
1572		return;
1573
1574	spin_lock_irq(&uport->lock);
1575	uport->ops->stop_rx(uport);
1576	spin_unlock_irq(&uport->lock);
1577
1578	uart_port_shutdown(port);
1579
1580	/*
1581	 * It's possible for shutdown to be called after suspend if we get
1582	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
1583	 * we don't try to resume a port that has been shutdown.
1584	 */
1585	tty_port_set_suspended(port, 0);
1586
1587	uart_change_pm(state, UART_PM_STATE_OFF);
1588
1589}
1590
1591static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1592{
1593	struct uart_state *state = tty->driver_data;
1594	struct uart_port *port;
1595	unsigned long char_time, expire;
1596
1597	port = uart_port_ref(state);
1598	if (!port)
1599		return;
1600
1601	if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1602		uart_port_deref(port);
1603		return;
1604	}
1605
1606	/*
1607	 * Set the check interval to be 1/5 of the estimated time to
1608	 * send a single character, and make it at least 1.  The check
1609	 * interval should also be less than the timeout.
1610	 *
1611	 * Note: we have to use pretty tight timings here to satisfy
1612	 * the NIST-PCTS.
1613	 */
1614	char_time = (port->timeout - HZ/50) / port->fifosize;
1615	char_time = char_time / 5;
1616	if (char_time == 0)
1617		char_time = 1;
1618	if (timeout && timeout < char_time)
1619		char_time = timeout;
1620
1621	/*
1622	 * If the transmitter hasn't cleared in twice the approximate
1623	 * amount of time to send the entire FIFO, it probably won't
1624	 * ever clear.  This assumes the UART isn't doing flow
1625	 * control, which is currently the case.  Hence, if it ever
1626	 * takes longer than port->timeout, this is probably due to a
1627	 * UART bug of some kind.  So, we clamp the timeout parameter at
1628	 * 2*port->timeout.
1629	 */
1630	if (timeout == 0 || timeout > 2 * port->timeout)
1631		timeout = 2 * port->timeout;
1632
1633	expire = jiffies + timeout;
1634
1635	pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1636		port->line, jiffies, expire);
1637
1638	/*
1639	 * Check whether the transmitter is empty every 'char_time'.
1640	 * 'timeout' / 'expire' give us the maximum amount of time
1641	 * we wait.
1642	 */
1643	while (!port->ops->tx_empty(port)) {
1644		msleep_interruptible(jiffies_to_msecs(char_time));
1645		if (signal_pending(current))
1646			break;
1647		if (time_after(jiffies, expire))
1648			break;
1649	}
1650	uart_port_deref(port);
1651}
1652
1653/*
1654 * Calls to uart_hangup() are serialised by the tty_lock in
1655 *   drivers/tty/tty_io.c:do_tty_hangup()
1656 * This runs from a workqueue and can sleep for a _short_ time only.
1657 */
1658static void uart_hangup(struct tty_struct *tty)
1659{
1660	struct uart_state *state = tty->driver_data;
1661	struct tty_port *port = &state->port;
1662	struct uart_port *uport;
1663	unsigned long flags;
1664
1665	pr_debug("uart_hangup(%d)\n", tty->index);
1666
1667	mutex_lock(&port->mutex);
1668	uport = uart_port_check(state);
1669	WARN(!uport, "hangup of detached port!\n");
1670
1671	if (tty_port_active(port)) {
1672		uart_flush_buffer(tty);
1673		uart_shutdown(tty, state);
1674		spin_lock_irqsave(&port->lock, flags);
1675		port->count = 0;
1676		spin_unlock_irqrestore(&port->lock, flags);
1677		tty_port_set_active(port, 0);
1678		tty_port_tty_set(port, NULL);
1679		if (uport && !uart_console(uport))
1680			uart_change_pm(state, UART_PM_STATE_OFF);
1681		wake_up_interruptible(&port->open_wait);
1682		wake_up_interruptible(&port->delta_msr_wait);
1683	}
1684	mutex_unlock(&port->mutex);
1685}
1686
1687/* uport == NULL if uart_port has already been removed */
1688static void uart_port_shutdown(struct tty_port *port)
1689{
1690	struct uart_state *state = container_of(port, struct uart_state, port);
1691	struct uart_port *uport = uart_port_check(state);
1692
1693	/*
1694	 * clear delta_msr_wait queue to avoid mem leaks: we may free
1695	 * the irq here so the queue might never be woken up.  Note
1696	 * that we won't end up waiting on delta_msr_wait again since
1697	 * any outstanding file descriptors should be pointing at
1698	 * hung_up_tty_fops now.
1699	 */
1700	wake_up_interruptible(&port->delta_msr_wait);
1701
1702	/*
1703	 * Free the IRQ and disable the port.
1704	 */
1705	if (uport)
1706		uport->ops->shutdown(uport);
1707
1708	/*
1709	 * Ensure that the IRQ handler isn't running on another CPU.
1710	 */
1711	if (uport)
1712		synchronize_irq(uport->irq);
1713}
1714
1715static int uart_carrier_raised(struct tty_port *port)
1716{
1717	struct uart_state *state = container_of(port, struct uart_state, port);
1718	struct uart_port *uport;
1719	int mctrl;
1720
1721	uport = uart_port_ref(state);
1722	/*
1723	 * Should never observe uport == NULL since checks for hangup should
1724	 * abort the tty_port_block_til_ready() loop before checking for carrier
1725	 * raised -- but report carrier raised if it does anyway so open will
1726	 * continue and not sleep
1727	 */
1728	if (WARN_ON(!uport))
1729		return 1;
1730	spin_lock_irq(&uport->lock);
1731	uart_enable_ms(uport);
1732	mctrl = uport->ops->get_mctrl(uport);
1733	spin_unlock_irq(&uport->lock);
1734	uart_port_deref(uport);
1735	if (mctrl & TIOCM_CAR)
1736		return 1;
1737	return 0;
1738}
1739
1740static void uart_dtr_rts(struct tty_port *port, int raise)
1741{
1742	struct uart_state *state = container_of(port, struct uart_state, port);
1743	struct uart_port *uport;
1744
1745	uport = uart_port_ref(state);
1746	if (!uport)
1747		return;
1748	uart_port_dtr_rts(uport, raise);
1749	uart_port_deref(uport);
1750}
1751
1752static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1753{
1754	struct uart_driver *drv = driver->driver_state;
1755	struct uart_state *state = drv->state + tty->index;
1756
1757	tty->driver_data = state;
1758
1759	return tty_standard_install(driver, tty);
1760}
1761
1762/*
1763 * Calls to uart_open are serialised by the tty_lock in
1764 *   drivers/tty/tty_io.c:tty_open()
1765 * Note that if this fails, then uart_close() _will_ be called.
1766 *
1767 * In time, we want to scrap the "opening nonpresent ports"
1768 * behaviour and implement an alternative way for setserial
1769 * to set base addresses/ports/types.  This will allow us to
1770 * get rid of a certain amount of extra tests.
1771 */
1772static int uart_open(struct tty_struct *tty, struct file *filp)
1773{
1774	struct uart_state *state = tty->driver_data;
1775	int retval;
 
 
 
1776
1777	retval = tty_port_open(&state->port, tty, filp);
1778	if (retval > 0)
1779		retval = 0;
1780
1781	return retval;
1782}
1783
1784static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1785{
1786	struct uart_state *state = container_of(port, struct uart_state, port);
1787	struct uart_port *uport;
1788	int ret;
1789
1790	uport = uart_port_check(state);
1791	if (!uport || uport->flags & UPF_DEAD)
1792		return -ENXIO;
1793
1794	port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
1795
1796	/*
1797	 * Start up the serial port.
1798	 */
1799	ret = uart_startup(tty, state, 0);
1800	if (ret > 0)
1801		tty_port_set_active(port, 1);
1802
1803	return ret;
1804}
1805
1806static const char *uart_type(struct uart_port *port)
1807{
1808	const char *str = NULL;
1809
1810	if (port->ops->type)
1811		str = port->ops->type(port);
1812
1813	if (!str)
1814		str = "unknown";
1815
1816	return str;
1817}
1818
1819#ifdef CONFIG_PROC_FS
1820
1821static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1822{
1823	struct uart_state *state = drv->state + i;
1824	struct tty_port *port = &state->port;
1825	enum uart_pm_state pm_state;
1826	struct uart_port *uport;
1827	char stat_buf[32];
1828	unsigned int status;
1829	int mmio;
1830
1831	mutex_lock(&port->mutex);
1832	uport = uart_port_check(state);
1833	if (!uport)
1834		goto out;
1835
1836	mmio = uport->iotype >= UPIO_MEM;
1837	seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1838			uport->line, uart_type(uport),
1839			mmio ? "mmio:0x" : "port:",
1840			mmio ? (unsigned long long)uport->mapbase
1841			     : (unsigned long long)uport->iobase,
1842			uport->irq);
1843
1844	if (uport->type == PORT_UNKNOWN) {
1845		seq_putc(m, '\n');
1846		goto out;
1847	}
1848
1849	if (capable(CAP_SYS_ADMIN)) {
1850		pm_state = state->pm_state;
1851		if (pm_state != UART_PM_STATE_ON)
1852			uart_change_pm(state, UART_PM_STATE_ON);
1853		spin_lock_irq(&uport->lock);
1854		status = uport->ops->get_mctrl(uport);
1855		spin_unlock_irq(&uport->lock);
1856		if (pm_state != UART_PM_STATE_ON)
1857			uart_change_pm(state, pm_state);
1858
1859		seq_printf(m, " tx:%d rx:%d",
1860				uport->icount.tx, uport->icount.rx);
1861		if (uport->icount.frame)
1862			seq_printf(m, " fe:%d",	uport->icount.frame);
1863		if (uport->icount.parity)
1864			seq_printf(m, " pe:%d",	uport->icount.parity);
1865		if (uport->icount.brk)
1866			seq_printf(m, " brk:%d", uport->icount.brk);
1867		if (uport->icount.overrun)
1868			seq_printf(m, " oe:%d", uport->icount.overrun);
1869		if (uport->icount.buf_overrun)
1870			seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1871
1872#define INFOBIT(bit, str) \
1873	if (uport->mctrl & (bit)) \
1874		strncat(stat_buf, (str), sizeof(stat_buf) - \
1875			strlen(stat_buf) - 2)
1876#define STATBIT(bit, str) \
1877	if (status & (bit)) \
1878		strncat(stat_buf, (str), sizeof(stat_buf) - \
1879		       strlen(stat_buf) - 2)
1880
1881		stat_buf[0] = '\0';
1882		stat_buf[1] = '\0';
1883		INFOBIT(TIOCM_RTS, "|RTS");
1884		STATBIT(TIOCM_CTS, "|CTS");
1885		INFOBIT(TIOCM_DTR, "|DTR");
1886		STATBIT(TIOCM_DSR, "|DSR");
1887		STATBIT(TIOCM_CAR, "|CD");
1888		STATBIT(TIOCM_RNG, "|RI");
1889		if (stat_buf[0])
1890			stat_buf[0] = ' ';
1891
1892		seq_puts(m, stat_buf);
1893	}
1894	seq_putc(m, '\n');
1895#undef STATBIT
1896#undef INFOBIT
1897out:
1898	mutex_unlock(&port->mutex);
1899}
1900
1901static int uart_proc_show(struct seq_file *m, void *v)
1902{
1903	struct tty_driver *ttydrv = m->private;
1904	struct uart_driver *drv = ttydrv->driver_state;
1905	int i;
1906
1907	seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1908	for (i = 0; i < drv->nr; i++)
1909		uart_line_info(m, drv, i);
1910	return 0;
1911}
1912#endif
1913
1914static inline bool uart_console_enabled(struct uart_port *port)
1915{
1916	return uart_console(port) && (port->cons->flags & CON_ENABLED);
1917}
1918
1919static void uart_port_spin_lock_init(struct uart_port *port)
1920{
1921	spin_lock_init(&port->lock);
1922	lockdep_set_class(&port->lock, &port_lock_key);
1923}
 
 
 
1924
1925#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1926/**
1927 *	uart_console_write - write a console message to a serial port
1928 *	@port: the port to write the message
1929 *	@s: array of characters
1930 *	@count: number of characters in string to write
1931 *	@putchar: function to write character to port
1932 */
1933void uart_console_write(struct uart_port *port, const char *s,
1934			unsigned int count,
1935			void (*putchar)(struct uart_port *, int))
1936{
1937	unsigned int i;
1938
1939	for (i = 0; i < count; i++, s++) {
1940		if (*s == '\n')
1941			putchar(port, '\r');
1942		putchar(port, *s);
1943	}
1944}
1945EXPORT_SYMBOL_GPL(uart_console_write);
1946
1947/*
1948 *	Check whether an invalid uart number has been specified, and
1949 *	if so, search for the first available port that does have
1950 *	console support.
1951 */
1952struct uart_port * __init
1953uart_get_console(struct uart_port *ports, int nr, struct console *co)
1954{
1955	int idx = co->index;
1956
1957	if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1958				     ports[idx].membase == NULL))
1959		for (idx = 0; idx < nr; idx++)
1960			if (ports[idx].iobase != 0 ||
1961			    ports[idx].membase != NULL)
1962				break;
1963
1964	co->index = idx;
1965
1966	return ports + idx;
1967}
1968
1969/**
1970 *	uart_parse_earlycon - Parse earlycon options
1971 *	@p:	  ptr to 2nd field (ie., just beyond '<name>,')
1972 *	@iotype:  ptr for decoded iotype (out)
1973 *	@addr:    ptr for decoded mapbase/iobase (out)
1974 *	@options: ptr for <options> field; NULL if not present (out)
1975 *
1976 *	Decodes earlycon kernel command line parameters of the form
1977 *	   earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1978 *	   console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1979 *
1980 *	The optional form
1981 *
1982 *	   earlycon=<name>,0x<addr>,<options>
1983 *	   console=<name>,0x<addr>,<options>
1984 *
1985 *	is also accepted; the returned @iotype will be UPIO_MEM.
1986 *
1987 *	Returns 0 on success or -EINVAL on failure
1988 */
1989int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1990			char **options)
1991{
1992	if (strncmp(p, "mmio,", 5) == 0) {
1993		*iotype = UPIO_MEM;
1994		p += 5;
1995	} else if (strncmp(p, "mmio16,", 7) == 0) {
1996		*iotype = UPIO_MEM16;
1997		p += 7;
1998	} else if (strncmp(p, "mmio32,", 7) == 0) {
1999		*iotype = UPIO_MEM32;
2000		p += 7;
2001	} else if (strncmp(p, "mmio32be,", 9) == 0) {
2002		*iotype = UPIO_MEM32BE;
2003		p += 9;
2004	} else if (strncmp(p, "mmio32native,", 13) == 0) {
2005		*iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2006			UPIO_MEM32BE : UPIO_MEM32;
2007		p += 13;
2008	} else if (strncmp(p, "io,", 3) == 0) {
2009		*iotype = UPIO_PORT;
2010		p += 3;
2011	} else if (strncmp(p, "0x", 2) == 0) {
2012		*iotype = UPIO_MEM;
2013	} else {
2014		return -EINVAL;
2015	}
2016
2017	/*
2018	 * Before you replace it with kstrtoull(), think about options separator
2019	 * (',') it will not tolerate
2020	 */
2021	*addr = simple_strtoull(p, NULL, 0);
2022	p = strchr(p, ',');
2023	if (p)
2024		p++;
2025
2026	*options = p;
2027	return 0;
2028}
2029EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2030
2031/**
2032 *	uart_parse_options - Parse serial port baud/parity/bits/flow control.
2033 *	@options: pointer to option string
2034 *	@baud: pointer to an 'int' variable for the baud rate.
2035 *	@parity: pointer to an 'int' variable for the parity.
2036 *	@bits: pointer to an 'int' variable for the number of data bits.
2037 *	@flow: pointer to an 'int' variable for the flow control character.
2038 *
2039 *	uart_parse_options decodes a string containing the serial console
2040 *	options.  The format of the string is <baud><parity><bits><flow>,
2041 *	eg: 115200n8r
2042 */
2043void
2044uart_parse_options(const char *options, int *baud, int *parity,
2045		   int *bits, int *flow)
2046{
2047	const char *s = options;
2048
2049	*baud = simple_strtoul(s, NULL, 10);
2050	while (*s >= '0' && *s <= '9')
2051		s++;
2052	if (*s)
2053		*parity = *s++;
2054	if (*s)
2055		*bits = *s++ - '0';
2056	if (*s)
2057		*flow = *s;
2058}
2059EXPORT_SYMBOL_GPL(uart_parse_options);
2060
2061/**
2062 *	uart_set_options - setup the serial console parameters
2063 *	@port: pointer to the serial ports uart_port structure
2064 *	@co: console pointer
2065 *	@baud: baud rate
2066 *	@parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2067 *	@bits: number of data bits
2068 *	@flow: flow control character - 'r' (rts)
2069 */
2070int
2071uart_set_options(struct uart_port *port, struct console *co,
2072		 int baud, int parity, int bits, int flow)
2073{
2074	struct ktermios termios;
2075	static struct ktermios dummy;
2076
2077	/*
2078	 * Ensure that the serial-console lock is initialised early.
2079	 *
2080	 * Note that the console-enabled check is needed because of kgdboc,
2081	 * which can end up calling uart_set_options() for an already enabled
2082	 * console via tty_find_polling_driver() and uart_poll_init().
2083	 */
2084	if (!uart_console_enabled(port) && !port->console_reinit)
2085		uart_port_spin_lock_init(port);
 
 
2086
2087	memset(&termios, 0, sizeof(struct ktermios));
2088
2089	termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2090	tty_termios_encode_baud_rate(&termios, baud, baud);
2091
2092	if (bits == 7)
2093		termios.c_cflag |= CS7;
2094	else
2095		termios.c_cflag |= CS8;
2096
2097	switch (parity) {
2098	case 'o': case 'O':
2099		termios.c_cflag |= PARODD;
2100		fallthrough;
2101	case 'e': case 'E':
2102		termios.c_cflag |= PARENB;
2103		break;
2104	}
2105
2106	if (flow == 'r')
2107		termios.c_cflag |= CRTSCTS;
2108
2109	/*
2110	 * some uarts on other side don't support no flow control.
2111	 * So we set * DTR in host uart to make them happy
2112	 */
2113	port->mctrl |= TIOCM_DTR;
2114
2115	port->ops->set_termios(port, &termios, &dummy);
2116	/*
2117	 * Allow the setting of the UART parameters with a NULL console
2118	 * too:
2119	 */
2120	if (co)
2121		co->cflag = termios.c_cflag;
2122
2123	return 0;
2124}
2125EXPORT_SYMBOL_GPL(uart_set_options);
2126#endif /* CONFIG_SERIAL_CORE_CONSOLE */
2127
2128/**
2129 * uart_change_pm - set power state of the port
2130 *
2131 * @state: port descriptor
2132 * @pm_state: new state
2133 *
2134 * Locking: port->mutex has to be held
2135 */
2136static void uart_change_pm(struct uart_state *state,
2137			   enum uart_pm_state pm_state)
2138{
2139	struct uart_port *port = uart_port_check(state);
2140
2141	if (state->pm_state != pm_state) {
2142		if (port && port->ops->pm)
2143			port->ops->pm(port, pm_state, state->pm_state);
2144		state->pm_state = pm_state;
2145	}
2146}
2147
2148struct uart_match {
2149	struct uart_port *port;
2150	struct uart_driver *driver;
2151};
2152
2153static int serial_match_port(struct device *dev, void *data)
2154{
2155	struct uart_match *match = data;
2156	struct tty_driver *tty_drv = match->driver->tty_driver;
2157	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2158		match->port->line;
2159
2160	return dev->devt == devt; /* Actually, only one tty per port */
2161}
2162
2163int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2164{
2165	struct uart_state *state = drv->state + uport->line;
2166	struct tty_port *port = &state->port;
2167	struct device *tty_dev;
2168	struct uart_match match = {uport, drv};
2169
2170	mutex_lock(&port->mutex);
2171
2172	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2173	if (tty_dev && device_may_wakeup(tty_dev)) {
2174		enable_irq_wake(uport->irq);
2175		put_device(tty_dev);
2176		mutex_unlock(&port->mutex);
2177		return 0;
2178	}
2179	put_device(tty_dev);
2180
2181	/* Nothing to do if the console is not suspending */
2182	if (!console_suspend_enabled && uart_console(uport))
2183		goto unlock;
2184
2185	uport->suspended = 1;
2186
2187	if (tty_port_initialized(port)) {
2188		const struct uart_ops *ops = uport->ops;
2189		int tries;
2190
2191		tty_port_set_suspended(port, 1);
2192		tty_port_set_initialized(port, 0);
2193
2194		spin_lock_irq(&uport->lock);
2195		ops->stop_tx(uport);
2196		ops->set_mctrl(uport, 0);
2197		ops->stop_rx(uport);
2198		spin_unlock_irq(&uport->lock);
2199
2200		/*
2201		 * Wait for the transmitter to empty.
2202		 */
2203		for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2204			msleep(10);
2205		if (!tries)
2206			dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2207				uport->name);
2208
2209		ops->shutdown(uport);
2210	}
2211
2212	/*
2213	 * Disable the console device before suspending.
2214	 */
2215	if (uart_console(uport))
2216		console_stop(uport->cons);
2217
2218	uart_change_pm(state, UART_PM_STATE_OFF);
2219unlock:
2220	mutex_unlock(&port->mutex);
2221
2222	return 0;
2223}
2224
2225int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2226{
2227	struct uart_state *state = drv->state + uport->line;
2228	struct tty_port *port = &state->port;
2229	struct device *tty_dev;
2230	struct uart_match match = {uport, drv};
2231	struct ktermios termios;
2232
2233	mutex_lock(&port->mutex);
2234
2235	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2236	if (!uport->suspended && device_may_wakeup(tty_dev)) {
2237		if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2238			disable_irq_wake(uport->irq);
2239		put_device(tty_dev);
2240		mutex_unlock(&port->mutex);
2241		return 0;
2242	}
2243	put_device(tty_dev);
2244	uport->suspended = 0;
2245
2246	/*
2247	 * Re-enable the console device after suspending.
2248	 */
2249	if (uart_console(uport)) {
2250		/*
2251		 * First try to use the console cflag setting.
2252		 */
2253		memset(&termios, 0, sizeof(struct ktermios));
2254		termios.c_cflag = uport->cons->cflag;
2255
2256		/*
2257		 * If that's unset, use the tty termios setting.
2258		 */
2259		if (port->tty && termios.c_cflag == 0)
2260			termios = port->tty->termios;
2261
2262		if (console_suspend_enabled)
2263			uart_change_pm(state, UART_PM_STATE_ON);
2264		uport->ops->set_termios(uport, &termios, NULL);
2265		if (console_suspend_enabled)
2266			console_start(uport->cons);
2267	}
2268
2269	if (tty_port_suspended(port)) {
2270		const struct uart_ops *ops = uport->ops;
2271		int ret;
2272
2273		uart_change_pm(state, UART_PM_STATE_ON);
2274		spin_lock_irq(&uport->lock);
2275		ops->set_mctrl(uport, 0);
2276		spin_unlock_irq(&uport->lock);
2277		if (console_suspend_enabled || !uart_console(uport)) {
2278			/* Protected by port mutex for now */
2279			struct tty_struct *tty = port->tty;
2280
2281			ret = ops->startup(uport);
2282			if (ret == 0) {
2283				if (tty)
2284					uart_change_speed(tty, state, NULL);
2285				spin_lock_irq(&uport->lock);
2286				ops->set_mctrl(uport, uport->mctrl);
2287				ops->start_tx(uport);
2288				spin_unlock_irq(&uport->lock);
2289				tty_port_set_initialized(port, 1);
2290			} else {
2291				/*
2292				 * Failed to resume - maybe hardware went away?
2293				 * Clear the "initialized" flag so we won't try
2294				 * to call the low level drivers shutdown method.
2295				 */
2296				uart_shutdown(tty, state);
2297			}
2298		}
2299
2300		tty_port_set_suspended(port, 0);
2301	}
2302
2303	mutex_unlock(&port->mutex);
2304
2305	return 0;
2306}
2307
2308static inline void
2309uart_report_port(struct uart_driver *drv, struct uart_port *port)
2310{
2311	char address[64];
2312
2313	switch (port->iotype) {
2314	case UPIO_PORT:
2315		snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2316		break;
2317	case UPIO_HUB6:
2318		snprintf(address, sizeof(address),
2319			 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2320		break;
2321	case UPIO_MEM:
2322	case UPIO_MEM16:
2323	case UPIO_MEM32:
2324	case UPIO_MEM32BE:
2325	case UPIO_AU:
2326	case UPIO_TSI:
2327		snprintf(address, sizeof(address),
2328			 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2329		break;
2330	default:
2331		strlcpy(address, "*unknown*", sizeof(address));
2332		break;
2333	}
2334
2335	pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2336	       port->dev ? dev_name(port->dev) : "",
2337	       port->dev ? ": " : "",
2338	       port->name,
2339	       address, port->irq, port->uartclk / 16, uart_type(port));
2340}
2341
2342static void
2343uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2344		    struct uart_port *port)
2345{
2346	unsigned int flags;
2347
2348	/*
2349	 * If there isn't a port here, don't do anything further.
2350	 */
2351	if (!port->iobase && !port->mapbase && !port->membase)
2352		return;
2353
2354	/*
2355	 * Now do the auto configuration stuff.  Note that config_port
2356	 * is expected to claim the resources and map the port for us.
2357	 */
2358	flags = 0;
2359	if (port->flags & UPF_AUTO_IRQ)
2360		flags |= UART_CONFIG_IRQ;
2361	if (port->flags & UPF_BOOT_AUTOCONF) {
2362		if (!(port->flags & UPF_FIXED_TYPE)) {
2363			port->type = PORT_UNKNOWN;
2364			flags |= UART_CONFIG_TYPE;
2365		}
2366		port->ops->config_port(port, flags);
2367	}
2368
2369	if (port->type != PORT_UNKNOWN) {
2370		unsigned long flags;
2371
2372		uart_report_port(drv, port);
2373
2374		/* Power up port for set_mctrl() */
2375		uart_change_pm(state, UART_PM_STATE_ON);
2376
2377		/*
2378		 * Ensure that the modem control lines are de-activated.
2379		 * keep the DTR setting that is set in uart_set_options()
2380		 * We probably don't need a spinlock around this, but
2381		 */
2382		spin_lock_irqsave(&port->lock, flags);
2383		port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2384		spin_unlock_irqrestore(&port->lock, flags);
2385
2386		/*
2387		 * If this driver supports console, and it hasn't been
2388		 * successfully registered yet, try to re-register it.
2389		 * It may be that the port was not available.
2390		 */
2391		if (port->cons && !(port->cons->flags & CON_ENABLED))
2392			register_console(port->cons);
2393
2394		/*
2395		 * Power down all ports by default, except the
2396		 * console if we have one.
2397		 */
2398		if (!uart_console(port))
2399			uart_change_pm(state, UART_PM_STATE_OFF);
2400	}
2401}
2402
2403#ifdef CONFIG_CONSOLE_POLL
2404
2405static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2406{
2407	struct uart_driver *drv = driver->driver_state;
2408	struct uart_state *state = drv->state + line;
2409	struct tty_port *tport;
2410	struct uart_port *port;
2411	int baud = 9600;
2412	int bits = 8;
2413	int parity = 'n';
2414	int flow = 'n';
2415	int ret = 0;
2416
2417	tport = &state->port;
2418	mutex_lock(&tport->mutex);
2419
2420	port = uart_port_check(state);
2421	if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2422		ret = -1;
2423		goto out;
2424	}
2425
2426	if (port->ops->poll_init) {
2427		/*
2428		 * We don't set initialized as we only initialized the hw,
2429		 * e.g. state->xmit is still uninitialized.
2430		 */
2431		if (!tty_port_initialized(tport))
2432			ret = port->ops->poll_init(port);
2433	}
2434
2435	if (!ret && options) {
2436		uart_parse_options(options, &baud, &parity, &bits, &flow);
2437		ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2438	}
2439out:
2440	mutex_unlock(&tport->mutex);
2441	return ret;
2442}
2443
2444static int uart_poll_get_char(struct tty_driver *driver, int line)
2445{
2446	struct uart_driver *drv = driver->driver_state;
2447	struct uart_state *state = drv->state + line;
2448	struct uart_port *port;
2449	int ret = -1;
2450
2451	port = uart_port_ref(state);
2452	if (port) {
2453		ret = port->ops->poll_get_char(port);
2454		uart_port_deref(port);
2455	}
2456
2457	return ret;
2458}
2459
2460static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2461{
2462	struct uart_driver *drv = driver->driver_state;
2463	struct uart_state *state = drv->state + line;
2464	struct uart_port *port;
2465
2466	port = uart_port_ref(state);
2467	if (!port)
2468		return;
2469
2470	if (ch == '\n')
2471		port->ops->poll_put_char(port, '\r');
2472	port->ops->poll_put_char(port, ch);
2473	uart_port_deref(port);
2474}
2475#endif
2476
2477static const struct tty_operations uart_ops = {
2478	.install	= uart_install,
2479	.open		= uart_open,
2480	.close		= uart_close,
2481	.write		= uart_write,
2482	.put_char	= uart_put_char,
2483	.flush_chars	= uart_flush_chars,
2484	.write_room	= uart_write_room,
2485	.chars_in_buffer= uart_chars_in_buffer,
2486	.flush_buffer	= uart_flush_buffer,
2487	.ioctl		= uart_ioctl,
2488	.throttle	= uart_throttle,
2489	.unthrottle	= uart_unthrottle,
2490	.send_xchar	= uart_send_xchar,
2491	.set_termios	= uart_set_termios,
2492	.set_ldisc	= uart_set_ldisc,
2493	.stop		= uart_stop,
2494	.start		= uart_start,
2495	.hangup		= uart_hangup,
2496	.break_ctl	= uart_break_ctl,
2497	.wait_until_sent= uart_wait_until_sent,
2498#ifdef CONFIG_PROC_FS
2499	.proc_show	= uart_proc_show,
2500#endif
2501	.tiocmget	= uart_tiocmget,
2502	.tiocmset	= uart_tiocmset,
2503	.set_serial	= uart_set_info_user,
2504	.get_serial	= uart_get_info_user,
2505	.get_icount	= uart_get_icount,
2506#ifdef CONFIG_CONSOLE_POLL
2507	.poll_init	= uart_poll_init,
2508	.poll_get_char	= uart_poll_get_char,
2509	.poll_put_char	= uart_poll_put_char,
2510#endif
2511};
2512
2513static const struct tty_port_operations uart_port_ops = {
2514	.carrier_raised = uart_carrier_raised,
2515	.dtr_rts	= uart_dtr_rts,
2516	.activate	= uart_port_activate,
2517	.shutdown	= uart_tty_port_shutdown,
2518};
2519
2520/**
2521 *	uart_register_driver - register a driver with the uart core layer
2522 *	@drv: low level driver structure
2523 *
2524 *	Register a uart driver with the core driver.  We in turn register
2525 *	with the tty layer, and initialise the core driver per-port state.
2526 *
2527 *	We have a proc file in /proc/tty/driver which is named after the
2528 *	normal driver.
2529 *
2530 *	drv->port should be NULL, and the per-port structures should be
2531 *	registered using uart_add_one_port after this call has succeeded.
2532 */
2533int uart_register_driver(struct uart_driver *drv)
2534{
2535	struct tty_driver *normal;
2536	int i, retval = -ENOMEM;
2537
2538	BUG_ON(drv->state);
2539
2540	/*
2541	 * Maybe we should be using a slab cache for this, especially if
2542	 * we have a large number of ports to handle.
2543	 */
2544	drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2545	if (!drv->state)
2546		goto out;
2547
2548	normal = alloc_tty_driver(drv->nr);
2549	if (!normal)
2550		goto out_kfree;
2551
2552	drv->tty_driver = normal;
2553
2554	normal->driver_name	= drv->driver_name;
2555	normal->name		= drv->dev_name;
2556	normal->major		= drv->major;
2557	normal->minor_start	= drv->minor;
2558	normal->type		= TTY_DRIVER_TYPE_SERIAL;
2559	normal->subtype		= SERIAL_TYPE_NORMAL;
2560	normal->init_termios	= tty_std_termios;
2561	normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2562	normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2563	normal->flags		= TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2564	normal->driver_state    = drv;
2565	tty_set_operations(normal, &uart_ops);
2566
2567	/*
2568	 * Initialise the UART state(s).
2569	 */
2570	for (i = 0; i < drv->nr; i++) {
2571		struct uart_state *state = drv->state + i;
2572		struct tty_port *port = &state->port;
2573
2574		tty_port_init(port);
2575		port->ops = &uart_port_ops;
2576	}
2577
2578	retval = tty_register_driver(normal);
2579	if (retval >= 0)
2580		return retval;
2581
2582	for (i = 0; i < drv->nr; i++)
2583		tty_port_destroy(&drv->state[i].port);
2584	put_tty_driver(normal);
2585out_kfree:
2586	kfree(drv->state);
2587out:
2588	return retval;
2589}
2590
2591/**
2592 *	uart_unregister_driver - remove a driver from the uart core layer
2593 *	@drv: low level driver structure
2594 *
2595 *	Remove all references to a driver from the core driver.  The low
2596 *	level driver must have removed all its ports via the
2597 *	uart_remove_one_port() if it registered them with uart_add_one_port().
2598 *	(ie, drv->port == NULL)
2599 */
2600void uart_unregister_driver(struct uart_driver *drv)
2601{
2602	struct tty_driver *p = drv->tty_driver;
2603	unsigned int i;
2604
2605	tty_unregister_driver(p);
2606	put_tty_driver(p);
2607	for (i = 0; i < drv->nr; i++)
2608		tty_port_destroy(&drv->state[i].port);
2609	kfree(drv->state);
2610	drv->state = NULL;
2611	drv->tty_driver = NULL;
2612}
2613
2614struct tty_driver *uart_console_device(struct console *co, int *index)
2615{
2616	struct uart_driver *p = co->data;
2617	*index = co->index;
2618	return p->tty_driver;
2619}
2620EXPORT_SYMBOL_GPL(uart_console_device);
2621
2622static ssize_t uartclk_show(struct device *dev,
2623	struct device_attribute *attr, char *buf)
2624{
2625	struct serial_struct tmp;
2626	struct tty_port *port = dev_get_drvdata(dev);
2627
2628	uart_get_info(port, &tmp);
2629	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.baud_base * 16);
2630}
2631
2632static ssize_t type_show(struct device *dev,
2633	struct device_attribute *attr, char *buf)
2634{
2635	struct serial_struct tmp;
2636	struct tty_port *port = dev_get_drvdata(dev);
2637
2638	uart_get_info(port, &tmp);
2639	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.type);
2640}
2641
2642static ssize_t line_show(struct device *dev,
2643	struct device_attribute *attr, char *buf)
2644{
2645	struct serial_struct tmp;
2646	struct tty_port *port = dev_get_drvdata(dev);
2647
2648	uart_get_info(port, &tmp);
2649	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.line);
2650}
2651
2652static ssize_t port_show(struct device *dev,
2653	struct device_attribute *attr, char *buf)
2654{
2655	struct serial_struct tmp;
2656	struct tty_port *port = dev_get_drvdata(dev);
2657	unsigned long ioaddr;
2658
2659	uart_get_info(port, &tmp);
2660	ioaddr = tmp.port;
2661	if (HIGH_BITS_OFFSET)
2662		ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2663	return snprintf(buf, PAGE_SIZE, "0x%lX\n", ioaddr);
2664}
2665
2666static ssize_t irq_show(struct device *dev,
2667	struct device_attribute *attr, char *buf)
2668{
2669	struct serial_struct tmp;
2670	struct tty_port *port = dev_get_drvdata(dev);
2671
2672	uart_get_info(port, &tmp);
2673	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.irq);
2674}
2675
2676static ssize_t flags_show(struct device *dev,
2677	struct device_attribute *attr, char *buf)
2678{
2679	struct serial_struct tmp;
2680	struct tty_port *port = dev_get_drvdata(dev);
2681
2682	uart_get_info(port, &tmp);
2683	return snprintf(buf, PAGE_SIZE, "0x%X\n", tmp.flags);
2684}
2685
2686static ssize_t xmit_fifo_size_show(struct device *dev,
2687	struct device_attribute *attr, char *buf)
2688{
2689	struct serial_struct tmp;
2690	struct tty_port *port = dev_get_drvdata(dev);
2691
2692	uart_get_info(port, &tmp);
2693	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.xmit_fifo_size);
2694}
2695
2696static ssize_t close_delay_show(struct device *dev,
 
2697	struct device_attribute *attr, char *buf)
2698{
2699	struct serial_struct tmp;
2700	struct tty_port *port = dev_get_drvdata(dev);
2701
2702	uart_get_info(port, &tmp);
2703	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.close_delay);
2704}
2705
2706static ssize_t closing_wait_show(struct device *dev,
 
2707	struct device_attribute *attr, char *buf)
2708{
2709	struct serial_struct tmp;
2710	struct tty_port *port = dev_get_drvdata(dev);
2711
2712	uart_get_info(port, &tmp);
2713	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.closing_wait);
2714}
2715
2716static ssize_t custom_divisor_show(struct device *dev,
2717	struct device_attribute *attr, char *buf)
2718{
2719	struct serial_struct tmp;
2720	struct tty_port *port = dev_get_drvdata(dev);
2721
2722	uart_get_info(port, &tmp);
2723	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.custom_divisor);
2724}
2725
2726static ssize_t io_type_show(struct device *dev,
2727	struct device_attribute *attr, char *buf)
2728{
2729	struct serial_struct tmp;
2730	struct tty_port *port = dev_get_drvdata(dev);
2731
2732	uart_get_info(port, &tmp);
2733	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.io_type);
2734}
2735
2736static ssize_t iomem_base_show(struct device *dev,
2737	struct device_attribute *attr, char *buf)
2738{
2739	struct serial_struct tmp;
2740	struct tty_port *port = dev_get_drvdata(dev);
2741
2742	uart_get_info(port, &tmp);
2743	return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)tmp.iomem_base);
2744}
2745
2746static ssize_t iomem_reg_shift_show(struct device *dev,
2747	struct device_attribute *attr, char *buf)
2748{
2749	struct serial_struct tmp;
2750	struct tty_port *port = dev_get_drvdata(dev);
2751
2752	uart_get_info(port, &tmp);
2753	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.iomem_reg_shift);
2754}
2755
2756static ssize_t console_show(struct device *dev,
2757	struct device_attribute *attr, char *buf)
2758{
2759	struct tty_port *port = dev_get_drvdata(dev);
2760	struct uart_state *state = container_of(port, struct uart_state, port);
2761	struct uart_port *uport;
2762	bool console = false;
2763
2764	mutex_lock(&port->mutex);
2765	uport = uart_port_check(state);
2766	if (uport)
2767		console = uart_console_enabled(uport);
2768	mutex_unlock(&port->mutex);
2769
2770	return sprintf(buf, "%c\n", console ? 'Y' : 'N');
2771}
2772
2773static ssize_t console_store(struct device *dev,
2774	struct device_attribute *attr, const char *buf, size_t count)
2775{
2776	struct tty_port *port = dev_get_drvdata(dev);
2777	struct uart_state *state = container_of(port, struct uart_state, port);
2778	struct uart_port *uport;
2779	bool oldconsole, newconsole;
2780	int ret;
2781
2782	ret = kstrtobool(buf, &newconsole);
2783	if (ret)
2784		return ret;
2785
2786	mutex_lock(&port->mutex);
2787	uport = uart_port_check(state);
2788	if (uport) {
2789		oldconsole = uart_console_enabled(uport);
2790		if (oldconsole && !newconsole) {
2791			ret = unregister_console(uport->cons);
2792		} else if (!oldconsole && newconsole) {
2793			if (uart_console(uport)) {
2794				uport->console_reinit = 1;
2795				register_console(uport->cons);
2796			} else {
2797				ret = -ENOENT;
2798			}
2799		}
2800	} else {
2801		ret = -ENXIO;
2802	}
2803	mutex_unlock(&port->mutex);
2804
2805	return ret < 0 ? ret : count;
2806}
2807
2808static DEVICE_ATTR_RO(uartclk);
2809static DEVICE_ATTR_RO(type);
2810static DEVICE_ATTR_RO(line);
2811static DEVICE_ATTR_RO(port);
2812static DEVICE_ATTR_RO(irq);
2813static DEVICE_ATTR_RO(flags);
2814static DEVICE_ATTR_RO(xmit_fifo_size);
2815static DEVICE_ATTR_RO(close_delay);
2816static DEVICE_ATTR_RO(closing_wait);
2817static DEVICE_ATTR_RO(custom_divisor);
2818static DEVICE_ATTR_RO(io_type);
2819static DEVICE_ATTR_RO(iomem_base);
2820static DEVICE_ATTR_RO(iomem_reg_shift);
2821static DEVICE_ATTR_RW(console);
2822
2823static struct attribute *tty_dev_attrs[] = {
2824	&dev_attr_uartclk.attr,
2825	&dev_attr_type.attr,
2826	&dev_attr_line.attr,
2827	&dev_attr_port.attr,
2828	&dev_attr_irq.attr,
2829	&dev_attr_flags.attr,
2830	&dev_attr_xmit_fifo_size.attr,
 
2831	&dev_attr_close_delay.attr,
2832	&dev_attr_closing_wait.attr,
2833	&dev_attr_custom_divisor.attr,
2834	&dev_attr_io_type.attr,
2835	&dev_attr_iomem_base.attr,
2836	&dev_attr_iomem_reg_shift.attr,
2837	&dev_attr_console.attr,
2838	NULL
2839};
2840
2841static const struct attribute_group tty_dev_attr_group = {
2842	.attrs = tty_dev_attrs,
2843};
2844
2845/**
2846 *	uart_add_one_port - attach a driver-defined port structure
2847 *	@drv: pointer to the uart low level driver structure for this port
2848 *	@uport: uart port structure to use for this port.
2849 *
2850 *	This allows the driver to register its own uart_port structure
2851 *	with the core driver.  The main purpose is to allow the low
2852 *	level uart drivers to expand uart_port, rather than having yet
2853 *	more levels of structures.
2854 */
2855int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2856{
2857	struct uart_state *state;
2858	struct tty_port *port;
2859	int ret = 0;
2860	struct device *tty_dev;
2861	int num_groups;
2862
2863	BUG_ON(in_interrupt());
2864
2865	if (uport->line >= drv->nr)
2866		return -EINVAL;
2867
2868	state = drv->state + uport->line;
2869	port = &state->port;
2870
2871	mutex_lock(&port_mutex);
2872	mutex_lock(&port->mutex);
2873	if (state->uart_port) {
2874		ret = -EINVAL;
2875		goto out;
2876	}
2877
2878	/* Link the port to the driver state table and vice versa */
2879	atomic_set(&state->refcount, 1);
2880	init_waitqueue_head(&state->remove_wait);
2881	state->uart_port = uport;
2882	uport->state = state;
2883
2884	state->pm_state = UART_PM_STATE_UNDEFINED;
2885	uport->cons = drv->cons;
2886	uport->minor = drv->tty_driver->minor_start + uport->line;
2887	uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2888				drv->tty_driver->name_base + uport->line);
2889	if (!uport->name) {
2890		ret = -ENOMEM;
2891		goto out;
2892	}
2893
2894	/*
2895	 * If this port is in use as a console then the spinlock is already
2896	 * initialised.
2897	 */
2898	if (!uart_console_enabled(uport))
2899		uart_port_spin_lock_init(uport);
2900
 
2901	if (uport->cons && uport->dev)
2902		of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2903
2904	tty_port_link_device(port, drv->tty_driver, uport->line);
2905	uart_configure_port(drv, state, uport);
2906
2907	port->console = uart_console(uport);
2908
2909	num_groups = 2;
2910	if (uport->attr_group)
2911		num_groups++;
2912
2913	uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2914				    GFP_KERNEL);
2915	if (!uport->tty_groups) {
2916		ret = -ENOMEM;
2917		goto out;
2918	}
2919	uport->tty_groups[0] = &tty_dev_attr_group;
2920	if (uport->attr_group)
2921		uport->tty_groups[1] = uport->attr_group;
2922
2923	/*
2924	 * Register the port whether it's detected or not.  This allows
2925	 * setserial to be used to alter this port's parameters.
2926	 */
2927	tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2928			uport->line, uport->dev, port, uport->tty_groups);
2929	if (!IS_ERR(tty_dev)) {
2930		device_set_wakeup_capable(tty_dev, 1);
2931	} else {
2932		dev_err(uport->dev, "Cannot register tty device on line %d\n",
2933		       uport->line);
2934	}
2935
2936	/*
2937	 * Ensure UPF_DEAD is not set.
2938	 */
2939	uport->flags &= ~UPF_DEAD;
2940
2941 out:
2942	mutex_unlock(&port->mutex);
2943	mutex_unlock(&port_mutex);
2944
2945	return ret;
2946}
2947
2948/**
2949 *	uart_remove_one_port - detach a driver defined port structure
2950 *	@drv: pointer to the uart low level driver structure for this port
2951 *	@uport: uart port structure for this port
2952 *
2953 *	This unhooks (and hangs up) the specified port structure from the
2954 *	core driver.  No further calls will be made to the low-level code
2955 *	for this port.
2956 */
2957int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2958{
2959	struct uart_state *state = drv->state + uport->line;
2960	struct tty_port *port = &state->port;
2961	struct uart_port *uart_port;
2962	struct tty_struct *tty;
2963	int ret = 0;
2964
2965	BUG_ON(in_interrupt());
2966
2967	mutex_lock(&port_mutex);
2968
2969	/*
2970	 * Mark the port "dead" - this prevents any opens from
2971	 * succeeding while we shut down the port.
2972	 */
2973	mutex_lock(&port->mutex);
2974	uart_port = uart_port_check(state);
2975	if (uart_port != uport)
2976		dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2977			  uart_port, uport);
2978
2979	if (!uart_port) {
2980		mutex_unlock(&port->mutex);
2981		ret = -EINVAL;
2982		goto out;
2983	}
2984	uport->flags |= UPF_DEAD;
2985	mutex_unlock(&port->mutex);
2986
2987	/*
2988	 * Remove the devices from the tty layer
2989	 */
2990	tty_port_unregister_device(port, drv->tty_driver, uport->line);
2991
2992	tty = tty_port_tty_get(port);
2993	if (tty) {
2994		tty_vhangup(port->tty);
2995		tty_kref_put(tty);
2996	}
2997
2998	/*
2999	 * If the port is used as a console, unregister it
3000	 */
3001	if (uart_console(uport))
3002		unregister_console(uport->cons);
3003
3004	/*
3005	 * Free the port IO and memory resources, if any.
3006	 */
3007	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3008		uport->ops->release_port(uport);
3009	kfree(uport->tty_groups);
3010	kfree(uport->name);
3011
3012	/*
3013	 * Indicate that there isn't a port here anymore.
3014	 */
3015	uport->type = PORT_UNKNOWN;
3016
3017	mutex_lock(&port->mutex);
3018	WARN_ON(atomic_dec_return(&state->refcount) < 0);
3019	wait_event(state->remove_wait, !atomic_read(&state->refcount));
3020	state->uart_port = NULL;
3021	mutex_unlock(&port->mutex);
3022out:
3023	mutex_unlock(&port_mutex);
3024
3025	return ret;
3026}
3027
3028/*
3029 *	Are the two ports equivalent?
3030 */
3031int uart_match_port(struct uart_port *port1, struct uart_port *port2)
3032{
3033	if (port1->iotype != port2->iotype)
3034		return 0;
3035
3036	switch (port1->iotype) {
3037	case UPIO_PORT:
3038		return (port1->iobase == port2->iobase);
3039	case UPIO_HUB6:
3040		return (port1->iobase == port2->iobase) &&
3041		       (port1->hub6   == port2->hub6);
3042	case UPIO_MEM:
3043	case UPIO_MEM16:
3044	case UPIO_MEM32:
3045	case UPIO_MEM32BE:
3046	case UPIO_AU:
3047	case UPIO_TSI:
3048		return (port1->mapbase == port2->mapbase);
3049	}
3050	return 0;
3051}
3052EXPORT_SYMBOL(uart_match_port);
3053
3054/**
3055 *	uart_handle_dcd_change - handle a change of carrier detect state
3056 *	@uport: uart_port structure for the open port
3057 *	@status: new carrier detect status, nonzero if active
3058 *
3059 *	Caller must hold uport->lock
3060 */
3061void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
3062{
3063	struct tty_port *port = &uport->state->port;
3064	struct tty_struct *tty = port->tty;
3065	struct tty_ldisc *ld;
3066
3067	lockdep_assert_held_once(&uport->lock);
3068
3069	if (tty) {
3070		ld = tty_ldisc_ref(tty);
3071		if (ld) {
3072			if (ld->ops->dcd_change)
3073				ld->ops->dcd_change(tty, status);
3074			tty_ldisc_deref(ld);
3075		}
3076	}
3077
3078	uport->icount.dcd++;
3079
3080	if (uart_dcd_enabled(uport)) {
3081		if (status)
3082			wake_up_interruptible(&port->open_wait);
3083		else if (tty)
3084			tty_hangup(tty);
3085	}
3086}
3087EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3088
3089/**
3090 *	uart_handle_cts_change - handle a change of clear-to-send state
3091 *	@uport: uart_port structure for the open port
3092 *	@status: new clear to send status, nonzero if active
3093 *
3094 *	Caller must hold uport->lock
3095 */
3096void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3097{
3098	lockdep_assert_held_once(&uport->lock);
3099
3100	uport->icount.cts++;
3101
3102	if (uart_softcts_mode(uport)) {
3103		if (uport->hw_stopped) {
3104			if (status) {
3105				uport->hw_stopped = 0;
3106				uport->ops->start_tx(uport);
3107				uart_write_wakeup(uport);
3108			}
3109		} else {
3110			if (!status) {
3111				uport->hw_stopped = 1;
3112				uport->ops->stop_tx(uport);
3113			}
3114		}
3115
3116	}
3117}
3118EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3119
3120/**
3121 * uart_insert_char - push a char to the uart layer
3122 *
3123 * User is responsible to call tty_flip_buffer_push when they are done with
3124 * insertion.
3125 *
3126 * @port: corresponding port
3127 * @status: state of the serial port RX buffer (LSR for 8250)
3128 * @overrun: mask of overrun bits in @status
3129 * @ch: character to push
3130 * @flag: flag for the character (see TTY_NORMAL and friends)
3131 */
3132void uart_insert_char(struct uart_port *port, unsigned int status,
3133		 unsigned int overrun, unsigned int ch, unsigned int flag)
3134{
3135	struct tty_port *tport = &port->state->port;
3136
3137	if ((status & port->ignore_status_mask & ~overrun) == 0)
3138		if (tty_insert_flip_char(tport, ch, flag) == 0)
3139			++port->icount.buf_overrun;
3140
3141	/*
3142	 * Overrun is special.  Since it's reported immediately,
3143	 * it doesn't affect the current character.
3144	 */
3145	if (status & ~port->ignore_status_mask & overrun)
3146		if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3147			++port->icount.buf_overrun;
3148}
3149EXPORT_SYMBOL_GPL(uart_insert_char);
3150
3151#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3152static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3153
3154static void uart_sysrq_on(struct work_struct *w)
3155{
3156	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3157
3158	sysrq_toggle_support(1);
3159	pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3160		sysrq_toggle_seq_len, sysrq_toggle_seq);
3161}
3162static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3163
3164/**
3165 *	uart_try_toggle_sysrq - Enables SysRq from serial line
3166 *	@port: uart_port structure where char(s) after BREAK met
3167 *	@ch: new character in the sequence after received BREAK
3168 *
3169 *	Enables magic SysRq when the required sequence is met on port
3170 *	(see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3171 *
3172 *	Returns false if @ch is out of enabling sequence and should be
3173 *	handled some other way, true if @ch was consumed.
3174 */
3175bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
3176{
3177	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3178
3179	if (!sysrq_toggle_seq_len)
3180		return false;
3181
3182	BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3183	if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3184		port->sysrq_seq = 0;
3185		return false;
3186	}
3187
3188	if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3189		port->sysrq = jiffies + SYSRQ_TIMEOUT;
3190		return true;
3191	}
3192
3193	schedule_work(&sysrq_enable_work);
3194
3195	port->sysrq = 0;
3196	return true;
3197}
3198EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3199#endif
3200
3201EXPORT_SYMBOL(uart_write_wakeup);
3202EXPORT_SYMBOL(uart_register_driver);
3203EXPORT_SYMBOL(uart_unregister_driver);
3204EXPORT_SYMBOL(uart_suspend_port);
3205EXPORT_SYMBOL(uart_resume_port);
3206EXPORT_SYMBOL(uart_add_one_port);
3207EXPORT_SYMBOL(uart_remove_one_port);
3208
3209/**
3210 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3211 * @port: uart device's target port
 
3212 *
3213 * This function implements the device tree binding described in
3214 * Documentation/devicetree/bindings/serial/rs485.txt.
3215 */
3216int uart_get_rs485_mode(struct uart_port *port)
3217{
3218	struct serial_rs485 *rs485conf = &port->rs485;
3219	struct device *dev = port->dev;
3220	u32 rs485_delay[2];
3221	int ret;
3222
3223	ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3224					     rs485_delay, 2);
3225	if (!ret) {
3226		rs485conf->delay_rts_before_send = rs485_delay[0];
3227		rs485conf->delay_rts_after_send = rs485_delay[1];
3228	} else {
3229		rs485conf->delay_rts_before_send = 0;
3230		rs485conf->delay_rts_after_send = 0;
3231	}
3232
3233	/*
3234	 * Clear full-duplex and enabled flags, set RTS polarity to active high
3235	 * to get to a defined state with the following properties:
3236	 */
3237	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3238			      SER_RS485_TERMINATE_BUS |
3239			      SER_RS485_RTS_AFTER_SEND);
3240	rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3241
3242	if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3243		rs485conf->flags |= SER_RS485_RX_DURING_TX;
3244
3245	if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3246		rs485conf->flags |= SER_RS485_ENABLED;
3247
3248	if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3249		rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3250		rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3251	}
3252
3253	/*
3254	 * Disabling termination by default is the safe choice:  Else if many
3255	 * bus participants enable it, no communication is possible at all.
3256	 * Works fine for short cables and users may enable for longer cables.
3257	 */
3258	port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3259							GPIOD_OUT_LOW);
3260	if (IS_ERR(port->rs485_term_gpio)) {
3261		ret = PTR_ERR(port->rs485_term_gpio);
3262		port->rs485_term_gpio = NULL;
3263		if (ret != -EPROBE_DEFER)
3264			dev_err(dev, "Cannot get rs485-term-gpios\n");
3265		return ret;
3266	}
3267
3268	return 0;
3269}
3270EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3271
3272MODULE_DESCRIPTION("Serial driver core");
3273MODULE_LICENSE("GPL");