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1// SPDX-License-Identifier: GPL-2.0+2/*3 *  Driver core for serial ports4 *5 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.6 *7 *  Copyright 1999 ARM Limited8 *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.9 */10#include <linux/module.h>11#include <linux/tty.h>12#include <linux/tty_flip.h>13#include <linux/slab.h>14#include <linux/sched/signal.h>15#include <linux/init.h>16#include <linux/console.h>17#include <linux/gpio/consumer.h>18#include <linux/kernel.h>19#include <linux/of.h>20#include <linux/pm_runtime.h>21#include <linux/proc_fs.h>22#include <linux/seq_file.h>23#include <linux/device.h>24#include <linux/serial.h> /* for serial_state and serial_icounter_struct */25#include <linux/serial_core.h>26#include <linux/sysrq.h>27#include <linux/delay.h>28#include <linux/mutex.h>29#include <linux/math64.h>30#include <linux/security.h>31 32#include <linux/irq.h>33#include <linux/uaccess.h>34 35#include "serial_base.h"36 37/*38 * This is used to lock changes in serial line configuration.39 */40static DEFINE_MUTEX(port_mutex);41 42/*43 * lockdep: port->lock is initialized in two places, but we44 *          want only one lock-class:45 */46static struct lock_class_key port_lock_key;47 48#define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)49 50/*51 * Max time with active RTS before/after data is sent.52 */53#define RS485_MAX_RTS_DELAY	100 /* msecs */54 55static void uart_change_pm(struct uart_state *state,56			   enum uart_pm_state pm_state);57 58static void uart_port_shutdown(struct tty_port *port);59 60static int uart_dcd_enabled(struct uart_port *uport)61{62	return !!(uport->status & UPSTAT_DCD_ENABLE);63}64 65static inline struct uart_port *uart_port_ref(struct uart_state *state)66{67	if (atomic_add_unless(&state->refcount, 1, 0))68		return state->uart_port;69	return NULL;70}71 72static inline void uart_port_deref(struct uart_port *uport)73{74	if (atomic_dec_and_test(&uport->state->refcount))75		wake_up(&uport->state->remove_wait);76}77 78#define uart_port_lock(state, flags)					\79	({								\80		struct uart_port *__uport = uart_port_ref(state);	\81		if (__uport)						\82			uart_port_lock_irqsave(__uport, &flags);	\83		__uport;						\84	})85 86#define uart_port_unlock(uport, flags)					\87	({								\88		struct uart_port *__uport = uport;			\89		if (__uport) {						\90			uart_port_unlock_irqrestore(__uport, flags);	\91			uart_port_deref(__uport);			\92		}							\93	})94 95static inline struct uart_port *uart_port_check(struct uart_state *state)96{97	lockdep_assert_held(&state->port.mutex);98	return state->uart_port;99}100 101/**102 * uart_write_wakeup - schedule write processing103 * @port: port to be processed104 *105 * This routine is used by the interrupt handler to schedule processing in the106 * software interrupt portion of the driver. A driver is expected to call this107 * function when the number of characters in the transmit buffer have dropped108 * below a threshold.109 *110 * Locking: @port->lock should be held111 */112void uart_write_wakeup(struct uart_port *port)113{114	struct uart_state *state = port->state;115	/*116	 * This means you called this function _after_ the port was117	 * closed.  No cookie for you.118	 */119	BUG_ON(!state);120	tty_port_tty_wakeup(&state->port);121}122EXPORT_SYMBOL(uart_write_wakeup);123 124static void uart_stop(struct tty_struct *tty)125{126	struct uart_state *state = tty->driver_data;127	struct uart_port *port;128	unsigned long flags;129 130	port = uart_port_lock(state, flags);131	if (port)132		port->ops->stop_tx(port);133	uart_port_unlock(port, flags);134}135 136static void __uart_start(struct uart_state *state)137{138	struct uart_port *port = state->uart_port;139	struct serial_port_device *port_dev;140	int err;141 142	if (!port || port->flags & UPF_DEAD || uart_tx_stopped(port))143		return;144 145	port_dev = port->port_dev;146 147	/* Increment the runtime PM usage count for the active check below */148	err = pm_runtime_get(&port_dev->dev);149	if (err < 0 && err != -EINPROGRESS) {150		pm_runtime_put_noidle(&port_dev->dev);151		return;152	}153 154	/*155	 * Start TX if enabled, and kick runtime PM. If the device is not156	 * enabled, serial_port_runtime_resume() calls start_tx() again157	 * after enabling the device.158	 */159	if (!pm_runtime_enabled(port->dev) || pm_runtime_active(&port_dev->dev))160		port->ops->start_tx(port);161	pm_runtime_mark_last_busy(&port_dev->dev);162	pm_runtime_put_autosuspend(&port_dev->dev);163}164 165static void uart_start(struct tty_struct *tty)166{167	struct uart_state *state = tty->driver_data;168	struct uart_port *port;169	unsigned long flags;170 171	port = uart_port_lock(state, flags);172	__uart_start(state);173	uart_port_unlock(port, flags);174}175 176static void177uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)178{179	unsigned long flags;180	unsigned int old;181 182	uart_port_lock_irqsave(port, &flags);183	old = port->mctrl;184	port->mctrl = (old & ~clear) | set;185	if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))186		port->ops->set_mctrl(port, port->mctrl);187	uart_port_unlock_irqrestore(port, flags);188}189 190#define uart_set_mctrl(port, set)	uart_update_mctrl(port, set, 0)191#define uart_clear_mctrl(port, clear)	uart_update_mctrl(port, 0, clear)192 193static void uart_port_dtr_rts(struct uart_port *uport, bool active)194{195	if (active)196		uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);197	else198		uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);199}200 201/* Caller holds port mutex */202static void uart_change_line_settings(struct tty_struct *tty, struct uart_state *state,203				      const struct ktermios *old_termios)204{205	struct uart_port *uport = uart_port_check(state);206	struct ktermios *termios;207	bool old_hw_stopped;208 209	/*210	 * If we have no tty, termios, or the port does not exist,211	 * then we can't set the parameters for this port.212	 */213	if (!tty || uport->type == PORT_UNKNOWN)214		return;215 216	termios = &tty->termios;217	uport->ops->set_termios(uport, termios, old_termios);218 219	/*220	 * Set modem status enables based on termios cflag221	 */222	uart_port_lock_irq(uport);223	if (termios->c_cflag & CRTSCTS)224		uport->status |= UPSTAT_CTS_ENABLE;225	else226		uport->status &= ~UPSTAT_CTS_ENABLE;227 228	if (termios->c_cflag & CLOCAL)229		uport->status &= ~UPSTAT_DCD_ENABLE;230	else231		uport->status |= UPSTAT_DCD_ENABLE;232 233	/* reset sw-assisted CTS flow control based on (possibly) new mode */234	old_hw_stopped = uport->hw_stopped;235	uport->hw_stopped = uart_softcts_mode(uport) &&236			    !(uport->ops->get_mctrl(uport) & TIOCM_CTS);237	if (uport->hw_stopped != old_hw_stopped) {238		if (!old_hw_stopped)239			uport->ops->stop_tx(uport);240		else241			__uart_start(state);242	}243	uart_port_unlock_irq(uport);244}245 246static int uart_alloc_xmit_buf(struct tty_port *port)247{248	struct uart_state *state = container_of(port, struct uart_state, port);249	struct uart_port *uport;250	unsigned long flags;251	unsigned long page;252 253	/*254	 * Initialise and allocate the transmit and temporary255	 * buffer.256	 */257	page = get_zeroed_page(GFP_KERNEL);258	if (!page)259		return -ENOMEM;260 261	uport = uart_port_lock(state, flags);262	if (!state->port.xmit_buf) {263		state->port.xmit_buf = (unsigned char *)page;264		kfifo_init(&state->port.xmit_fifo, state->port.xmit_buf,265				PAGE_SIZE);266		uart_port_unlock(uport, flags);267	} else {268		uart_port_unlock(uport, flags);269		/*270		 * Do not free() the page under the port lock, see271		 * uart_free_xmit_buf().272		 */273		free_page(page);274	}275 276	return 0;277}278 279static void uart_free_xmit_buf(struct tty_port *port)280{281	struct uart_state *state = container_of(port, struct uart_state, port);282	struct uart_port *uport;283	unsigned long flags;284	char *xmit_buf;285 286	/*287	 * Do not free() the transmit buffer page under the port lock since288	 * this can create various circular locking scenarios. For instance,289	 * console driver may need to allocate/free a debug object, which290	 * can end up in printk() recursion.291	 */292	uport = uart_port_lock(state, flags);293	xmit_buf = port->xmit_buf;294	port->xmit_buf = NULL;295	INIT_KFIFO(port->xmit_fifo);296	uart_port_unlock(uport, flags);297 298	free_page((unsigned long)xmit_buf);299}300 301/*302 * Startup the port.  This will be called once per open.  All calls303 * will be serialised by the per-port mutex.304 */305static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,306			     bool init_hw)307{308	struct uart_port *uport = uart_port_check(state);309	int retval;310 311	if (uport->type == PORT_UNKNOWN)312		return 1;313 314	/*315	 * Make sure the device is in D0 state.316	 */317	uart_change_pm(state, UART_PM_STATE_ON);318 319	retval = uart_alloc_xmit_buf(&state->port);320	if (retval)321		return retval;322 323	retval = uport->ops->startup(uport);324	if (retval == 0) {325		if (uart_console(uport) && uport->cons->cflag) {326			tty->termios.c_cflag = uport->cons->cflag;327			tty->termios.c_ispeed = uport->cons->ispeed;328			tty->termios.c_ospeed = uport->cons->ospeed;329			uport->cons->cflag = 0;330			uport->cons->ispeed = 0;331			uport->cons->ospeed = 0;332		}333		/*334		 * Initialise the hardware port settings.335		 */336		uart_change_line_settings(tty, state, NULL);337 338		/*339		 * Setup the RTS and DTR signals once the340		 * port is open and ready to respond.341		 */342		if (init_hw && C_BAUD(tty))343			uart_port_dtr_rts(uport, true);344	}345 346	/*347	 * This is to allow setserial on this port. People may want to set348	 * port/irq/type and then reconfigure the port properly if it failed349	 * now.350	 */351	if (retval && capable(CAP_SYS_ADMIN))352		return 1;353 354	return retval;355}356 357static int uart_startup(struct tty_struct *tty, struct uart_state *state,358			bool init_hw)359{360	struct tty_port *port = &state->port;361	struct uart_port *uport;362	int retval;363 364	if (tty_port_initialized(port))365		goto out_base_port_startup;366 367	retval = uart_port_startup(tty, state, init_hw);368	if (retval) {369		set_bit(TTY_IO_ERROR, &tty->flags);370		return retval;371	}372 373out_base_port_startup:374	uport = uart_port_check(state);375	if (!uport)376		return -EIO;377 378	serial_base_port_startup(uport);379 380	return 0;381}382 383/*384 * This routine will shutdown a serial port; interrupts are disabled, and385 * DTR is dropped if the hangup on close termio flag is on.  Calls to386 * uart_shutdown are serialised by the per-port semaphore.387 *388 * uport == NULL if uart_port has already been removed389 */390static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)391{392	struct uart_port *uport = uart_port_check(state);393	struct tty_port *port = &state->port;394 395	/*396	 * Set the TTY IO error marker397	 */398	if (tty)399		set_bit(TTY_IO_ERROR, &tty->flags);400 401	if (uport)402		serial_base_port_shutdown(uport);403 404	if (tty_port_initialized(port)) {405		tty_port_set_initialized(port, false);406 407		/*408		 * Turn off DTR and RTS early.409		 */410		if (uport) {411			if (uart_console(uport) && tty) {412				uport->cons->cflag = tty->termios.c_cflag;413				uport->cons->ispeed = tty->termios.c_ispeed;414				uport->cons->ospeed = tty->termios.c_ospeed;415			}416 417			if (!tty || C_HUPCL(tty))418				uart_port_dtr_rts(uport, false);419		}420 421		uart_port_shutdown(port);422	}423 424	/*425	 * It's possible for shutdown to be called after suspend if we get426	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so427	 * we don't try to resume a port that has been shutdown.428	 */429	tty_port_set_suspended(port, false);430 431	uart_free_xmit_buf(port);432}433 434/**435 * uart_update_timeout - update per-port frame timing information436 * @port: uart_port structure describing the port437 * @cflag: termios cflag value438 * @baud: speed of the port439 *440 * Set the @port frame timing information from which the FIFO timeout value is441 * derived. The @cflag value should reflect the actual hardware settings as442 * number of bits, parity, stop bits and baud rate is taken into account here.443 *444 * Locking: caller is expected to take @port->lock445 */446void447uart_update_timeout(struct uart_port *port, unsigned int cflag,448		    unsigned int baud)449{450	u64 temp = tty_get_frame_size(cflag);451 452	temp *= NSEC_PER_SEC;453	port->frame_time = (unsigned int)DIV64_U64_ROUND_UP(temp, baud);454}455EXPORT_SYMBOL(uart_update_timeout);456 457/**458 * uart_get_baud_rate - return baud rate for a particular port459 * @port: uart_port structure describing the port in question.460 * @termios: desired termios settings461 * @old: old termios (or %NULL)462 * @min: minimum acceptable baud rate463 * @max: maximum acceptable baud rate464 *465 * Decode the termios structure into a numeric baud rate, taking account of the466 * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600467 * baud.468 *469 * If the new baud rate is invalid, try the @old termios setting. If it's still470 * invalid, we try 9600 baud. If that is also invalid 0 is returned.471 *472 * The @termios structure is updated to reflect the baud rate we're actually473 * going to be using. Don't do this for the case where B0 is requested ("hang474 * up").475 *476 * Locking: caller dependent477 */478unsigned int479uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,480		   const struct ktermios *old, unsigned int min, unsigned int max)481{482	unsigned int try;483	unsigned int baud;484	unsigned int altbaud;485	int hung_up = 0;486	upf_t flags = port->flags & UPF_SPD_MASK;487 488	switch (flags) {489	case UPF_SPD_HI:490		altbaud = 57600;491		break;492	case UPF_SPD_VHI:493		altbaud = 115200;494		break;495	case UPF_SPD_SHI:496		altbaud = 230400;497		break;498	case UPF_SPD_WARP:499		altbaud = 460800;500		break;501	default:502		altbaud = 38400;503		break;504	}505 506	for (try = 0; try < 2; try++) {507		baud = tty_termios_baud_rate(termios);508 509		/*510		 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...511		 * Die! Die! Die!512		 */513		if (try == 0 && baud == 38400)514			baud = altbaud;515 516		/*517		 * Special case: B0 rate.518		 */519		if (baud == 0) {520			hung_up = 1;521			baud = 9600;522		}523 524		if (baud >= min && baud <= max)525			return baud;526 527		/*528		 * Oops, the quotient was zero.  Try again with529		 * the old baud rate if possible.530		 */531		termios->c_cflag &= ~CBAUD;532		if (old) {533			baud = tty_termios_baud_rate(old);534			if (!hung_up)535				tty_termios_encode_baud_rate(termios,536								baud, baud);537			old = NULL;538			continue;539		}540 541		/*542		 * As a last resort, if the range cannot be met then clip to543		 * the nearest chip supported rate.544		 */545		if (!hung_up) {546			if (baud <= min)547				tty_termios_encode_baud_rate(termios,548							min + 1, min + 1);549			else550				tty_termios_encode_baud_rate(termios,551							max - 1, max - 1);552		}553	}554	return 0;555}556EXPORT_SYMBOL(uart_get_baud_rate);557 558/**559 * uart_get_divisor - return uart clock divisor560 * @port: uart_port structure describing the port561 * @baud: desired baud rate562 *563 * Calculate the divisor (baud_base / baud) for the specified @baud,564 * appropriately rounded.565 *566 * If 38400 baud and custom divisor is selected, return the custom divisor567 * instead.568 *569 * Locking: caller dependent570 */571unsigned int572uart_get_divisor(struct uart_port *port, unsigned int baud)573{574	unsigned int quot;575 576	/*577	 * Old custom speed handling.578	 */579	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)580		quot = port->custom_divisor;581	else582		quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);583 584	return quot;585}586EXPORT_SYMBOL(uart_get_divisor);587 588static int uart_put_char(struct tty_struct *tty, u8 c)589{590	struct uart_state *state = tty->driver_data;591	struct uart_port *port;592	unsigned long flags;593	int ret = 0;594 595	port = uart_port_lock(state, flags);596	if (!state->port.xmit_buf) {597		uart_port_unlock(port, flags);598		return 0;599	}600 601	if (port)602		ret = kfifo_put(&state->port.xmit_fifo, c);603	uart_port_unlock(port, flags);604	return ret;605}606 607static void uart_flush_chars(struct tty_struct *tty)608{609	uart_start(tty);610}611 612static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)613{614	struct uart_state *state = tty->driver_data;615	struct uart_port *port;616	unsigned long flags;617	int ret = 0;618 619	/*620	 * This means you called this function _after_ the port was621	 * closed.  No cookie for you.622	 */623	if (WARN_ON(!state))624		return -EL3HLT;625 626	port = uart_port_lock(state, flags);627	if (!state->port.xmit_buf) {628		uart_port_unlock(port, flags);629		return 0;630	}631 632	if (port)633		ret = kfifo_in(&state->port.xmit_fifo, buf, count);634 635	__uart_start(state);636	uart_port_unlock(port, flags);637	return ret;638}639 640static unsigned int uart_write_room(struct tty_struct *tty)641{642	struct uart_state *state = tty->driver_data;643	struct uart_port *port;644	unsigned long flags;645	unsigned int ret;646 647	port = uart_port_lock(state, flags);648	ret = kfifo_avail(&state->port.xmit_fifo);649	uart_port_unlock(port, flags);650	return ret;651}652 653static unsigned int uart_chars_in_buffer(struct tty_struct *tty)654{655	struct uart_state *state = tty->driver_data;656	struct uart_port *port;657	unsigned long flags;658	unsigned int ret;659 660	port = uart_port_lock(state, flags);661	ret = kfifo_len(&state->port.xmit_fifo);662	uart_port_unlock(port, flags);663	return ret;664}665 666static void uart_flush_buffer(struct tty_struct *tty)667{668	struct uart_state *state = tty->driver_data;669	struct uart_port *port;670	unsigned long flags;671 672	/*673	 * This means you called this function _after_ the port was674	 * closed.  No cookie for you.675	 */676	if (WARN_ON(!state))677		return;678 679	pr_debug("uart_flush_buffer(%d) called\n", tty->index);680 681	port = uart_port_lock(state, flags);682	if (!port)683		return;684	kfifo_reset(&state->port.xmit_fifo);685	if (port->ops->flush_buffer)686		port->ops->flush_buffer(port);687	uart_port_unlock(port, flags);688	tty_port_tty_wakeup(&state->port);689}690 691/*692 * This function performs low-level write of high-priority XON/XOFF693 * character and accounting for it.694 *695 * Requires uart_port to implement .serial_out().696 */697void uart_xchar_out(struct uart_port *uport, int offset)698{699	serial_port_out(uport, offset, uport->x_char);700	uport->icount.tx++;701	uport->x_char = 0;702}703EXPORT_SYMBOL_GPL(uart_xchar_out);704 705/*706 * This function is used to send a high-priority XON/XOFF character to707 * the device708 */709static void uart_send_xchar(struct tty_struct *tty, u8 ch)710{711	struct uart_state *state = tty->driver_data;712	struct uart_port *port;713	unsigned long flags;714 715	port = uart_port_ref(state);716	if (!port)717		return;718 719	if (port->ops->send_xchar)720		port->ops->send_xchar(port, ch);721	else {722		uart_port_lock_irqsave(port, &flags);723		port->x_char = ch;724		if (ch)725			port->ops->start_tx(port);726		uart_port_unlock_irqrestore(port, flags);727	}728	uart_port_deref(port);729}730 731static void uart_throttle(struct tty_struct *tty)732{733	struct uart_state *state = tty->driver_data;734	upstat_t mask = UPSTAT_SYNC_FIFO;735	struct uart_port *port;736 737	port = uart_port_ref(state);738	if (!port)739		return;740 741	if (I_IXOFF(tty))742		mask |= UPSTAT_AUTOXOFF;743	if (C_CRTSCTS(tty))744		mask |= UPSTAT_AUTORTS;745 746	if (port->status & mask) {747		port->ops->throttle(port);748		mask &= ~port->status;749	}750 751	if (mask & UPSTAT_AUTORTS)752		uart_clear_mctrl(port, TIOCM_RTS);753 754	if (mask & UPSTAT_AUTOXOFF)755		uart_send_xchar(tty, STOP_CHAR(tty));756 757	uart_port_deref(port);758}759 760static void uart_unthrottle(struct tty_struct *tty)761{762	struct uart_state *state = tty->driver_data;763	upstat_t mask = UPSTAT_SYNC_FIFO;764	struct uart_port *port;765 766	port = uart_port_ref(state);767	if (!port)768		return;769 770	if (I_IXOFF(tty))771		mask |= UPSTAT_AUTOXOFF;772	if (C_CRTSCTS(tty))773		mask |= UPSTAT_AUTORTS;774 775	if (port->status & mask) {776		port->ops->unthrottle(port);777		mask &= ~port->status;778	}779 780	if (mask & UPSTAT_AUTORTS)781		uart_set_mctrl(port, TIOCM_RTS);782 783	if (mask & UPSTAT_AUTOXOFF)784		uart_send_xchar(tty, START_CHAR(tty));785 786	uart_port_deref(port);787}788 789static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)790{791	struct uart_state *state = container_of(port, struct uart_state, port);792	struct uart_port *uport;793	int ret = -ENODEV;794 795	/* Initialize structure in case we error out later to prevent any stack info leakage. */796	*retinfo = (struct serial_struct){};797 798	/*799	 * Ensure the state we copy is consistent and no hardware changes800	 * occur as we go801	 */802	mutex_lock(&port->mutex);803	uport = uart_port_check(state);804	if (!uport)805		goto out;806 807	retinfo->type	    = uport->type;808	retinfo->line	    = uport->line;809	retinfo->port	    = uport->iobase;810	if (HIGH_BITS_OFFSET)811		retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;812	retinfo->irq		    = uport->irq;813	retinfo->flags	    = (__force int)uport->flags;814	retinfo->xmit_fifo_size  = uport->fifosize;815	retinfo->baud_base	    = uport->uartclk / 16;816	retinfo->close_delay	    = jiffies_to_msecs(port->close_delay) / 10;817	retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?818				ASYNC_CLOSING_WAIT_NONE :819				jiffies_to_msecs(port->closing_wait) / 10;820	retinfo->custom_divisor  = uport->custom_divisor;821	retinfo->hub6	    = uport->hub6;822	retinfo->io_type         = uport->iotype;823	retinfo->iomem_reg_shift = uport->regshift;824	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;825 826	ret = 0;827out:828	mutex_unlock(&port->mutex);829	return ret;830}831 832static int uart_get_info_user(struct tty_struct *tty,833			 struct serial_struct *ss)834{835	struct uart_state *state = tty->driver_data;836	struct tty_port *port = &state->port;837 838	return uart_get_info(port, ss) < 0 ? -EIO : 0;839}840 841static int uart_set_info(struct tty_struct *tty, struct tty_port *port,842			 struct uart_state *state,843			 struct serial_struct *new_info)844{845	struct uart_port *uport = uart_port_check(state);846	unsigned long new_port;847	unsigned int change_irq, change_port, closing_wait;848	unsigned int old_custom_divisor, close_delay;849	upf_t old_flags, new_flags;850	int retval = 0;851 852	if (!uport)853		return -EIO;854 855	new_port = new_info->port;856	if (HIGH_BITS_OFFSET)857		new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;858 859	new_info->irq = irq_canonicalize(new_info->irq);860	close_delay = msecs_to_jiffies(new_info->close_delay * 10);861	closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?862			ASYNC_CLOSING_WAIT_NONE :863			msecs_to_jiffies(new_info->closing_wait * 10);864 865 866	change_irq  = !(uport->flags & UPF_FIXED_PORT)867		&& new_info->irq != uport->irq;868 869	/*870	 * Since changing the 'type' of the port changes its resource871	 * allocations, we should treat type changes the same as872	 * IO port changes.873	 */874	change_port = !(uport->flags & UPF_FIXED_PORT)875		&& (new_port != uport->iobase ||876		    (unsigned long)new_info->iomem_base != uport->mapbase ||877		    new_info->hub6 != uport->hub6 ||878		    new_info->io_type != uport->iotype ||879		    new_info->iomem_reg_shift != uport->regshift ||880		    new_info->type != uport->type);881 882	old_flags = uport->flags;883	new_flags = (__force upf_t)new_info->flags;884	old_custom_divisor = uport->custom_divisor;885 886	if (!(uport->flags & UPF_FIXED_PORT)) {887		unsigned int uartclk = new_info->baud_base * 16;888		/* check needs to be done here before other settings made */889		if (uartclk == 0) {890			retval = -EINVAL;891			goto exit;892		}893	}894	if (!capable(CAP_SYS_ADMIN)) {895		retval = -EPERM;896		if (change_irq || change_port ||897		    (new_info->baud_base != uport->uartclk / 16) ||898		    (close_delay != port->close_delay) ||899		    (closing_wait != port->closing_wait) ||900		    (new_info->xmit_fifo_size &&901		     new_info->xmit_fifo_size != uport->fifosize) ||902		    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))903			goto exit;904		uport->flags = ((uport->flags & ~UPF_USR_MASK) |905			       (new_flags & UPF_USR_MASK));906		uport->custom_divisor = new_info->custom_divisor;907		goto check_and_exit;908	}909 910	if (change_irq || change_port) {911		retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);912		if (retval)913			goto exit;914	}915 916	/*917	 * Ask the low level driver to verify the settings.918	 */919	if (uport->ops->verify_port)920		retval = uport->ops->verify_port(uport, new_info);921 922	if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||923	    (new_info->baud_base < 9600))924		retval = -EINVAL;925 926	if (retval)927		goto exit;928 929	if (change_port || change_irq) {930		retval = -EBUSY;931 932		/*933		 * Make sure that we are the sole user of this port.934		 */935		if (tty_port_users(port) > 1)936			goto exit;937 938		/*939		 * We need to shutdown the serial port at the old940		 * port/type/irq combination.941		 */942		uart_shutdown(tty, state);943	}944 945	if (change_port) {946		unsigned long old_iobase, old_mapbase;947		unsigned int old_type, old_iotype, old_hub6, old_shift;948 949		old_iobase = uport->iobase;950		old_mapbase = uport->mapbase;951		old_type = uport->type;952		old_hub6 = uport->hub6;953		old_iotype = uport->iotype;954		old_shift = uport->regshift;955 956		/*957		 * Free and release old regions958		 */959		if (old_type != PORT_UNKNOWN && uport->ops->release_port)960			uport->ops->release_port(uport);961 962		uport->iobase = new_port;963		uport->type = new_info->type;964		uport->hub6 = new_info->hub6;965		uport->iotype = new_info->io_type;966		uport->regshift = new_info->iomem_reg_shift;967		uport->mapbase = (unsigned long)new_info->iomem_base;968 969		/*970		 * Claim and map the new regions971		 */972		if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {973			retval = uport->ops->request_port(uport);974		} else {975			/* Always success - Jean II */976			retval = 0;977		}978 979		/*980		 * If we fail to request resources for the981		 * new port, try to restore the old settings.982		 */983		if (retval) {984			uport->iobase = old_iobase;985			uport->type = old_type;986			uport->hub6 = old_hub6;987			uport->iotype = old_iotype;988			uport->regshift = old_shift;989			uport->mapbase = old_mapbase;990 991			if (old_type != PORT_UNKNOWN) {992				retval = uport->ops->request_port(uport);993				/*994				 * If we failed to restore the old settings,995				 * we fail like this.996				 */997				if (retval)998					uport->type = PORT_UNKNOWN;999 1000				/*1001				 * We failed anyway.1002				 */1003				retval = -EBUSY;1004			}1005 1006			/* Added to return the correct error -Ram Gupta */1007			goto exit;1008		}1009	}1010 1011	if (change_irq)1012		uport->irq      = new_info->irq;1013	if (!(uport->flags & UPF_FIXED_PORT))1014		uport->uartclk  = new_info->baud_base * 16;1015	uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |1016				 (new_flags & UPF_CHANGE_MASK);1017	uport->custom_divisor   = new_info->custom_divisor;1018	port->close_delay     = close_delay;1019	port->closing_wait    = closing_wait;1020	if (new_info->xmit_fifo_size)1021		uport->fifosize = new_info->xmit_fifo_size;1022 1023 check_and_exit:1024	retval = 0;1025	if (uport->type == PORT_UNKNOWN)1026		goto exit;1027	if (tty_port_initialized(port)) {1028		if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||1029		    old_custom_divisor != uport->custom_divisor) {1030			/*1031			 * If they're setting up a custom divisor or speed,1032			 * instead of clearing it, then bitch about it.1033			 */1034			if (uport->flags & UPF_SPD_MASK) {1035				dev_notice_ratelimited(uport->dev,1036				       "%s sets custom speed on %s. This is deprecated.\n",1037				      current->comm,1038				      tty_name(port->tty));1039			}1040			uart_change_line_settings(tty, state, NULL);1041		}1042	} else {1043		retval = uart_startup(tty, state, true);1044		if (retval == 0)1045			tty_port_set_initialized(port, true);1046		if (retval > 0)1047			retval = 0;1048	}1049 exit:1050	return retval;1051}1052 1053static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)1054{1055	struct uart_state *state = tty->driver_data;1056	struct tty_port *port = &state->port;1057	int retval;1058 1059	down_write(&tty->termios_rwsem);1060	/*1061	 * This semaphore protects port->count.  It is also1062	 * very useful to prevent opens.  Also, take the1063	 * port configuration semaphore to make sure that a1064	 * module insertion/removal doesn't change anything1065	 * under us.1066	 */1067	mutex_lock(&port->mutex);1068	retval = uart_set_info(tty, port, state, ss);1069	mutex_unlock(&port->mutex);1070	up_write(&tty->termios_rwsem);1071	return retval;1072}1073 1074/**1075 * uart_get_lsr_info - get line status register info1076 * @tty: tty associated with the UART1077 * @state: UART being queried1078 * @value: returned modem value1079 */1080static int uart_get_lsr_info(struct tty_struct *tty,1081			struct uart_state *state, unsigned int __user *value)1082{1083	struct uart_port *uport = uart_port_check(state);1084	unsigned int result;1085 1086	result = uport->ops->tx_empty(uport);1087 1088	/*1089	 * If we're about to load something into the transmit1090	 * register, we'll pretend the transmitter isn't empty to1091	 * avoid a race condition (depending on when the transmit1092	 * interrupt happens).1093	 */1094	if (uport->x_char ||1095	    (!kfifo_is_empty(&state->port.xmit_fifo) &&1096	     !uart_tx_stopped(uport)))1097		result &= ~TIOCSER_TEMT;1098 1099	return put_user(result, value);1100}1101 1102static int uart_tiocmget(struct tty_struct *tty)1103{1104	struct uart_state *state = tty->driver_data;1105	struct tty_port *port = &state->port;1106	struct uart_port *uport;1107	int result;1108 1109	guard(mutex)(&port->mutex);1110 1111	uport = uart_port_check(state);1112	if (!uport || tty_io_error(tty))1113		return -EIO;1114 1115	uart_port_lock_irq(uport);1116	result = uport->mctrl;1117	result |= uport->ops->get_mctrl(uport);1118	uart_port_unlock_irq(uport);1119 1120	return result;1121}1122 1123static int1124uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)1125{1126	struct uart_state *state = tty->driver_data;1127	struct tty_port *port = &state->port;1128	struct uart_port *uport;1129 1130	guard(mutex)(&port->mutex);1131 1132	uport = uart_port_check(state);1133	if (!uport || tty_io_error(tty))1134		return -EIO;1135 1136	uart_update_mctrl(uport, set, clear);1137 1138	return 0;1139}1140 1141static int uart_break_ctl(struct tty_struct *tty, int break_state)1142{1143	struct uart_state *state = tty->driver_data;1144	struct tty_port *port = &state->port;1145	struct uart_port *uport;1146 1147	guard(mutex)(&port->mutex);1148 1149	uport = uart_port_check(state);1150	if (!uport)1151		return -EIO;1152 1153	if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)1154		uport->ops->break_ctl(uport, break_state);1155 1156	return 0;1157}1158 1159static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)1160{1161	struct tty_port *port = &state->port;1162	struct uart_port *uport;1163	int flags, ret;1164 1165	if (!capable(CAP_SYS_ADMIN))1166		return -EPERM;1167 1168	/*1169	 * Take the per-port semaphore.  This prevents count from1170	 * changing, and hence any extra opens of the port while1171	 * we're auto-configuring.1172	 */1173	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &port->mutex) {1174		uport = uart_port_check(state);1175		if (!uport)1176			return -EIO;1177 1178		if (tty_port_users(port) != 1)1179			return -EBUSY;1180 1181		uart_shutdown(tty, state);1182 1183		/*1184		 * If we already have a port type configured,1185		 * we must release its resources.1186		 */1187		if (uport->type != PORT_UNKNOWN && uport->ops->release_port)1188			uport->ops->release_port(uport);1189 1190		flags = UART_CONFIG_TYPE;1191		if (uport->flags & UPF_AUTO_IRQ)1192			flags |= UART_CONFIG_IRQ;1193 1194		/*1195		 * This will claim the ports resources if1196		 * a port is found.1197		 */1198		uport->ops->config_port(uport, flags);1199 1200		ret = uart_startup(tty, state, true);1201		if (ret < 0)1202			return ret;1203		if (ret > 0)1204			return 0;1205 1206		tty_port_set_initialized(port, true);1207	}1208 1209	return 0;1210}1211 1212static void uart_enable_ms(struct uart_port *uport)1213{1214	/*1215	 * Force modem status interrupts on1216	 */1217	if (uport->ops->enable_ms)1218		uport->ops->enable_ms(uport);1219}1220 1221/*1222 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change1223 * - mask passed in arg for lines of interest1224 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)1225 * Caller should use TIOCGICOUNT to see which one it was1226 *1227 * FIXME: This wants extracting into a common all driver implementation1228 * of TIOCMWAIT using tty_port.1229 */1230static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)1231{1232	struct uart_port *uport;1233	struct tty_port *port = &state->port;1234	DECLARE_WAITQUEUE(wait, current);1235	struct uart_icount cprev, cnow;1236	int ret;1237 1238	/*1239	 * note the counters on entry1240	 */1241	uport = uart_port_ref(state);1242	if (!uport)1243		return -EIO;1244	uart_port_lock_irq(uport);1245	memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));1246	uart_enable_ms(uport);1247	uart_port_unlock_irq(uport);1248 1249	add_wait_queue(&port->delta_msr_wait, &wait);1250	for (;;) {1251		uart_port_lock_irq(uport);1252		memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));1253		uart_port_unlock_irq(uport);1254 1255		set_current_state(TASK_INTERRUPTIBLE);1256 1257		if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||1258		    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||1259		    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||1260		    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {1261			ret = 0;1262			break;1263		}1264 1265		schedule();1266 1267		/* see if a signal did it */1268		if (signal_pending(current)) {1269			ret = -ERESTARTSYS;1270			break;1271		}1272 1273		cprev = cnow;1274	}1275	__set_current_state(TASK_RUNNING);1276	remove_wait_queue(&port->delta_msr_wait, &wait);1277	uart_port_deref(uport);1278 1279	return ret;1280}1281 1282/*1283 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)1284 * Return: write counters to the user passed counter struct1285 * NB: both 1->0 and 0->1 transitions are counted except for1286 *     RI where only 0->1 is counted.1287 */1288static int uart_get_icount(struct tty_struct *tty,1289			  struct serial_icounter_struct *icount)1290{1291	struct uart_state *state = tty->driver_data;1292	struct uart_icount cnow;1293	struct uart_port *uport;1294 1295	uport = uart_port_ref(state);1296	if (!uport)1297		return -EIO;1298	uart_port_lock_irq(uport);1299	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));1300	uart_port_unlock_irq(uport);1301	uart_port_deref(uport);1302 1303	icount->cts         = cnow.cts;1304	icount->dsr         = cnow.dsr;1305	icount->rng         = cnow.rng;1306	icount->dcd         = cnow.dcd;1307	icount->rx          = cnow.rx;1308	icount->tx          = cnow.tx;1309	icount->frame       = cnow.frame;1310	icount->overrun     = cnow.overrun;1311	icount->parity      = cnow.parity;1312	icount->brk         = cnow.brk;1313	icount->buf_overrun = cnow.buf_overrun;1314 1315	return 0;1316}1317 1318#define SER_RS485_LEGACY_FLAGS	(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \1319				 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \1320				 SER_RS485_TERMINATE_BUS)1321 1322static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)1323{1324	u32 flags = rs485->flags;1325 1326	/* Don't return -EINVAL for unsupported legacy flags */1327	flags &= ~SER_RS485_LEGACY_FLAGS;1328 1329	/*1330	 * For any bit outside of the legacy ones that is not supported by1331	 * the driver, return -EINVAL.1332	 */1333	if (flags & ~port->rs485_supported.flags)1334		return -EINVAL;1335 1336	/* Asking for address w/o addressing mode? */1337	if (!(rs485->flags & SER_RS485_ADDRB) &&1338	    (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))1339		return -EINVAL;1340 1341	/* Address given but not enabled? */1342	if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)1343		return -EINVAL;1344	if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)1345		return -EINVAL;1346 1347	return 0;1348}1349 1350static void uart_sanitize_serial_rs485_delays(struct uart_port *port,1351					      struct serial_rs485 *rs485)1352{1353	if (!port->rs485_supported.delay_rts_before_send) {1354		if (rs485->delay_rts_before_send) {1355			dev_warn_ratelimited(port->dev,1356				"%s (%d): RTS delay before sending not supported\n",1357				port->name, port->line);1358		}1359		rs485->delay_rts_before_send = 0;1360	} else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {1361		rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;1362		dev_warn_ratelimited(port->dev,1363			"%s (%d): RTS delay before sending clamped to %u ms\n",1364			port->name, port->line, rs485->delay_rts_before_send);1365	}1366 1367	if (!port->rs485_supported.delay_rts_after_send) {1368		if (rs485->delay_rts_after_send) {1369			dev_warn_ratelimited(port->dev,1370				"%s (%d): RTS delay after sending not supported\n",1371				port->name, port->line);1372		}1373		rs485->delay_rts_after_send = 0;1374	} else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {1375		rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;1376		dev_warn_ratelimited(port->dev,1377			"%s (%d): RTS delay after sending clamped to %u ms\n",1378			port->name, port->line, rs485->delay_rts_after_send);1379	}1380}1381 1382static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)1383{1384	u32 supported_flags = port->rs485_supported.flags;1385 1386	if (!(rs485->flags & SER_RS485_ENABLED)) {1387		memset(rs485, 0, sizeof(*rs485));1388		return;1389	}1390 1391	/* Clear other RS485 flags but SER_RS485_TERMINATE_BUS and return if enabling RS422 */1392	if (rs485->flags & SER_RS485_MODE_RS422) {1393		rs485->flags &= (SER_RS485_ENABLED | SER_RS485_MODE_RS422 | SER_RS485_TERMINATE_BUS);1394		return;1395	}1396 1397	rs485->flags &= supported_flags;1398 1399	/* Pick sane settings if the user hasn't */1400	if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==1401	    !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {1402		if (supported_flags & SER_RS485_RTS_ON_SEND) {1403			rs485->flags |= SER_RS485_RTS_ON_SEND;1404			rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;1405 1406			dev_warn_ratelimited(port->dev,1407				"%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",1408				port->name, port->line);1409		} else {1410			rs485->flags |= SER_RS485_RTS_AFTER_SEND;1411			rs485->flags &= ~SER_RS485_RTS_ON_SEND;1412 1413			dev_warn_ratelimited(port->dev,1414				"%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n",1415				port->name, port->line);1416		}1417	}1418 1419	uart_sanitize_serial_rs485_delays(port, rs485);1420 1421	/* Return clean padding area to userspace */1422	memset(rs485->padding0, 0, sizeof(rs485->padding0));1423	memset(rs485->padding1, 0, sizeof(rs485->padding1));1424}1425 1426static void uart_set_rs485_termination(struct uart_port *port,1427				       const struct serial_rs485 *rs485)1428{1429	if (!(rs485->flags & SER_RS485_ENABLED))1430		return;1431 1432	gpiod_set_value_cansleep(port->rs485_term_gpio,1433				 !!(rs485->flags & SER_RS485_TERMINATE_BUS));1434}1435 1436static void uart_set_rs485_rx_during_tx(struct uart_port *port,1437					const struct serial_rs485 *rs485)1438{1439	if (!(rs485->flags & SER_RS485_ENABLED))1440		return;1441 1442	gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,1443				 !!(rs485->flags & SER_RS485_RX_DURING_TX));1444}1445 1446static int uart_rs485_config(struct uart_port *port)1447{1448	struct serial_rs485 *rs485 = &port->rs485;1449	unsigned long flags;1450	int ret;1451 1452	if (!(rs485->flags & SER_RS485_ENABLED))1453		return 0;1454 1455	uart_sanitize_serial_rs485(port, rs485);1456	uart_set_rs485_termination(port, rs485);1457	uart_set_rs485_rx_during_tx(port, rs485);1458 1459	uart_port_lock_irqsave(port, &flags);1460	ret = port->rs485_config(port, NULL, rs485);1461	uart_port_unlock_irqrestore(port, flags);1462	if (ret) {1463		memset(rs485, 0, sizeof(*rs485));1464		/* unset GPIOs */1465		gpiod_set_value_cansleep(port->rs485_term_gpio, 0);1466		gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);1467	}1468 1469	return ret;1470}1471 1472static int uart_get_rs485_config(struct uart_port *port,1473			 struct serial_rs485 __user *rs485)1474{1475	unsigned long flags;1476	struct serial_rs485 aux;1477 1478	uart_port_lock_irqsave(port, &flags);1479	aux = port->rs485;1480	uart_port_unlock_irqrestore(port, flags);1481 1482	if (copy_to_user(rs485, &aux, sizeof(aux)))1483		return -EFAULT;1484 1485	return 0;1486}1487 1488static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,1489			 struct serial_rs485 __user *rs485_user)1490{1491	struct serial_rs485 rs485;1492	int ret;1493	unsigned long flags;1494 1495	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))1496		return -ENOTTY;1497 1498	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))1499		return -EFAULT;1500 1501	ret = uart_check_rs485_flags(port, &rs485);1502	if (ret)1503		return ret;1504	uart_sanitize_serial_rs485(port, &rs485);1505	uart_set_rs485_termination(port, &rs485);1506	uart_set_rs485_rx_during_tx(port, &rs485);1507 1508	uart_port_lock_irqsave(port, &flags);1509	ret = port->rs485_config(port, &tty->termios, &rs485);1510	if (!ret) {1511		port->rs485 = rs485;1512 1513		/* Reset RTS and other mctrl lines when disabling RS485 */1514		if (!(rs485.flags & SER_RS485_ENABLED))1515			port->ops->set_mctrl(port, port->mctrl);1516	}1517	uart_port_unlock_irqrestore(port, flags);1518	if (ret) {1519		/* restore old GPIO settings */1520		gpiod_set_value_cansleep(port->rs485_term_gpio,1521			!!(port->rs485.flags & SER_RS485_TERMINATE_BUS));1522		gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,1523			!!(port->rs485.flags & SER_RS485_RX_DURING_TX));1524		return ret;1525	}1526 1527	if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))1528		return -EFAULT;1529 1530	return 0;1531}1532 1533static int uart_get_iso7816_config(struct uart_port *port,1534				   struct serial_iso7816 __user *iso7816)1535{1536	unsigned long flags;1537	struct serial_iso7816 aux;1538 1539	if (!port->iso7816_config)1540		return -ENOTTY;1541 1542	uart_port_lock_irqsave(port, &flags);1543	aux = port->iso7816;1544	uart_port_unlock_irqrestore(port, flags);1545 1546	if (copy_to_user(iso7816, &aux, sizeof(aux)))1547		return -EFAULT;1548 1549	return 0;1550}1551 1552static int uart_set_iso7816_config(struct uart_port *port,1553				   struct serial_iso7816 __user *iso7816_user)1554{1555	struct serial_iso7816 iso7816;1556	int i, ret;1557	unsigned long flags;1558 1559	if (!port->iso7816_config)1560		return -ENOTTY;1561 1562	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))1563		return -EFAULT;1564 1565	/*1566	 * There are 5 words reserved for future use. Check that userspace1567	 * doesn't put stuff in there to prevent breakages in the future.1568	 */1569	for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)1570		if (iso7816.reserved[i])1571			return -EINVAL;1572 1573	uart_port_lock_irqsave(port, &flags);1574	ret = port->iso7816_config(port, &iso7816);1575	uart_port_unlock_irqrestore(port, flags);1576	if (ret)1577		return ret;1578 1579	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))1580		return -EFAULT;1581 1582	return 0;1583}1584 1585/*1586 * Called via sys_ioctl.  We can use spin_lock_irq() here.1587 */1588static int1589uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)1590{1591	struct uart_state *state = tty->driver_data;1592	struct tty_port *port = &state->port;1593	struct uart_port *uport;1594	void __user *uarg = (void __user *)arg;1595	int ret = -ENOIOCTLCMD;1596 1597 1598	/*1599	 * These ioctls don't rely on the hardware to be present.1600	 */1601	switch (cmd) {1602	case TIOCSERCONFIG:1603		down_write(&tty->termios_rwsem);1604		ret = uart_do_autoconfig(tty, state);1605		up_write(&tty->termios_rwsem);1606		break;1607	}1608 1609	if (ret != -ENOIOCTLCMD)1610		goto out;1611 1612	if (tty_io_error(tty)) {1613		ret = -EIO;1614		goto out;1615	}1616 1617	/*1618	 * The following should only be used when hardware is present.1619	 */1620	switch (cmd) {1621	case TIOCMIWAIT:1622		ret = uart_wait_modem_status(state, arg);1623		break;1624	}1625 1626	if (ret != -ENOIOCTLCMD)1627		goto out;1628 1629	/* rs485_config requires more locking than others */1630	if (cmd == TIOCSRS485)1631		down_write(&tty->termios_rwsem);1632 1633	mutex_lock(&port->mutex);1634	uport = uart_port_check(state);1635 1636	if (!uport || tty_io_error(tty)) {1637		ret = -EIO;1638		goto out_up;1639	}1640 1641	/*1642	 * All these rely on hardware being present and need to be1643	 * protected against the tty being hung up.1644	 */1645 1646	switch (cmd) {1647	case TIOCSERGETLSR: /* Get line status register */1648		ret = uart_get_lsr_info(tty, state, uarg);1649		break;1650 1651	case TIOCGRS485:1652		ret = uart_get_rs485_config(uport, uarg);1653		break;1654 1655	case TIOCSRS485:1656		ret = uart_set_rs485_config(tty, uport, uarg);1657		break;1658 1659	case TIOCSISO7816:1660		ret = uart_set_iso7816_config(state->uart_port, uarg);1661		break;1662 1663	case TIOCGISO7816:1664		ret = uart_get_iso7816_config(state->uart_port, uarg);1665		break;1666	default:1667		if (uport->ops->ioctl)1668			ret = uport->ops->ioctl(uport, cmd, arg);1669		break;1670	}1671out_up:1672	mutex_unlock(&port->mutex);1673	if (cmd == TIOCSRS485)1674		up_write(&tty->termios_rwsem);1675out:1676	return ret;1677}1678 1679static void uart_set_ldisc(struct tty_struct *tty)1680{1681	struct uart_state *state = tty->driver_data;1682	struct uart_port *uport;1683	struct tty_port *port = &state->port;1684 1685	if (!tty_port_initialized(port))1686		return;1687 1688	mutex_lock(&state->port.mutex);1689	uport = uart_port_check(state);1690	if (uport && uport->ops->set_ldisc)1691		uport->ops->set_ldisc(uport, &tty->termios);1692	mutex_unlock(&state->port.mutex);1693}1694 1695static void uart_set_termios(struct tty_struct *tty,1696			     const struct ktermios *old_termios)1697{1698	struct uart_state *state = tty->driver_data;1699	struct uart_port *uport;1700	unsigned int cflag = tty->termios.c_cflag;1701	unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;1702	bool sw_changed = false;1703 1704	guard(mutex)(&state->port.mutex);1705 1706	uport = uart_port_check(state);1707	if (!uport)1708		return;1709 1710	/*1711	 * Drivers doing software flow control also need to know1712	 * about changes to these input settings.1713	 */1714	if (uport->flags & UPF_SOFT_FLOW) {1715		iflag_mask |= IXANY|IXON|IXOFF;1716		sw_changed =1717		   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||1718		   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];1719	}1720 1721	/*1722	 * These are the bits that are used to setup various1723	 * flags in the low level driver. We can ignore the Bfoo1724	 * bits in c_cflag; c_[io]speed will always be set1725	 * appropriately by set_termios() in tty_ioctl.c1726	 */1727	if ((cflag ^ old_termios->c_cflag) == 0 &&1728	    tty->termios.c_ospeed == old_termios->c_ospeed &&1729	    tty->termios.c_ispeed == old_termios->c_ispeed &&1730	    ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&1731	    !sw_changed)1732		return;1733 1734	uart_change_line_settings(tty, state, old_termios);1735	/* reload cflag from termios; port driver may have overridden flags */1736	cflag = tty->termios.c_cflag;1737 1738	/* Handle transition to B0 status */1739	if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))1740		uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);1741	/* Handle transition away from B0 status */1742	else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {1743		unsigned int mask = TIOCM_DTR;1744 1745		if (!(cflag & CRTSCTS) || !tty_throttled(tty))1746			mask |= TIOCM_RTS;1747		uart_set_mctrl(uport, mask);1748	}1749}1750 1751/*1752 * Calls to uart_close() are serialised via the tty_lock in1753 *   drivers/tty/tty_io.c:tty_release()1754 *   drivers/tty/tty_io.c:do_tty_hangup()1755 */1756static void uart_close(struct tty_struct *tty, struct file *filp)1757{1758	struct uart_state *state = tty->driver_data;1759 1760	if (!state) {1761		struct uart_driver *drv = tty->driver->driver_state;1762		struct tty_port *port;1763 1764		state = drv->state + tty->index;1765		port = &state->port;1766		spin_lock_irq(&port->lock);1767		--port->count;1768		spin_unlock_irq(&port->lock);1769		return;1770	}1771 1772	pr_debug("uart_close(%d) called\n", tty->index);1773 1774	tty_port_close(tty->port, tty, filp);1775}1776 1777static void uart_tty_port_shutdown(struct tty_port *port)1778{1779	struct uart_state *state = container_of(port, struct uart_state, port);1780	struct uart_port *uport = uart_port_check(state);1781 1782	/*1783	 * At this point, we stop accepting input.  To do this, we1784	 * disable the receive line status interrupts.1785	 */1786	if (WARN(!uport, "detached port still initialized!\n"))1787		return;1788 1789	uart_port_lock_irq(uport);1790	uport->ops->stop_rx(uport);1791	uart_port_unlock_irq(uport);1792 1793	serial_base_port_shutdown(uport);1794	uart_port_shutdown(port);1795 1796	/*1797	 * It's possible for shutdown to be called after suspend if we get1798	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so1799	 * we don't try to resume a port that has been shutdown.1800	 */1801	tty_port_set_suspended(port, false);1802 1803	uart_free_xmit_buf(port);1804 1805	uart_change_pm(state, UART_PM_STATE_OFF);1806}1807 1808static void uart_wait_until_sent(struct tty_struct *tty, int timeout)1809{1810	struct uart_state *state = tty->driver_data;1811	struct uart_port *port;1812	unsigned long char_time, expire, fifo_timeout;1813 1814	port = uart_port_ref(state);1815	if (!port)1816		return;1817 1818	if (port->type == PORT_UNKNOWN || port->fifosize == 0) {1819		uart_port_deref(port);1820		return;1821	}1822 1823	/*1824	 * Set the check interval to be 1/5 of the estimated time to1825	 * send a single character, and make it at least 1.  The check1826	 * interval should also be less than the timeout.1827	 *1828	 * Note: we have to use pretty tight timings here to satisfy1829	 * the NIST-PCTS.1830	 */1831	char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);1832 1833	if (timeout && timeout < char_time)1834		char_time = timeout;1835 1836	if (!uart_cts_enabled(port)) {1837		/*1838		 * If the transmitter hasn't cleared in twice the approximate1839		 * amount of time to send the entire FIFO, it probably won't1840		 * ever clear.  This assumes the UART isn't doing flow1841		 * control, which is currently the case.  Hence, if it ever1842		 * takes longer than FIFO timeout, this is probably due to a1843		 * UART bug of some kind.  So, we clamp the timeout parameter at1844		 * 2 * FIFO timeout.1845		 */1846		fifo_timeout = uart_fifo_timeout(port);1847		if (timeout == 0 || timeout > 2 * fifo_timeout)1848			timeout = 2 * fifo_timeout;1849	}1850 1851	expire = jiffies + timeout;1852 1853	pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",1854		port->line, jiffies, expire);1855 1856	/*1857	 * Check whether the transmitter is empty every 'char_time'.1858	 * 'timeout' / 'expire' give us the maximum amount of time1859	 * we wait.1860	 */1861	while (!port->ops->tx_empty(port)) {1862		msleep_interruptible(jiffies_to_msecs(char_time));1863		if (signal_pending(current))1864			break;1865		if (timeout && time_after(jiffies, expire))1866			break;1867	}1868	uart_port_deref(port);1869}1870 1871/*1872 * Calls to uart_hangup() are serialised by the tty_lock in1873 *   drivers/tty/tty_io.c:do_tty_hangup()1874 * This runs from a workqueue and can sleep for a _short_ time only.1875 */1876static void uart_hangup(struct tty_struct *tty)1877{1878	struct uart_state *state = tty->driver_data;1879	struct tty_port *port = &state->port;1880	struct uart_port *uport;1881	unsigned long flags;1882 1883	pr_debug("uart_hangup(%d)\n", tty->index);1884 1885	mutex_lock(&port->mutex);1886	uport = uart_port_check(state);1887	WARN(!uport, "hangup of detached port!\n");1888 1889	if (tty_port_active(port)) {1890		uart_flush_buffer(tty);1891		uart_shutdown(tty, state);1892		spin_lock_irqsave(&port->lock, flags);1893		port->count = 0;1894		spin_unlock_irqrestore(&port->lock, flags);1895		tty_port_set_active(port, false);1896		tty_port_tty_set(port, NULL);1897		if (uport && !uart_console(uport))1898			uart_change_pm(state, UART_PM_STATE_OFF);1899		wake_up_interruptible(&port->open_wait);1900		wake_up_interruptible(&port->delta_msr_wait);1901	}1902	mutex_unlock(&port->mutex);1903}1904 1905/* uport == NULL if uart_port has already been removed */1906static void uart_port_shutdown(struct tty_port *port)1907{1908	struct uart_state *state = container_of(port, struct uart_state, port);1909	struct uart_port *uport = uart_port_check(state);1910 1911	/*1912	 * clear delta_msr_wait queue to avoid mem leaks: we may free1913	 * the irq here so the queue might never be woken up.  Note1914	 * that we won't end up waiting on delta_msr_wait again since1915	 * any outstanding file descriptors should be pointing at1916	 * hung_up_tty_fops now.1917	 */1918	wake_up_interruptible(&port->delta_msr_wait);1919 1920	if (uport) {1921		/* Free the IRQ and disable the port. */1922		uport->ops->shutdown(uport);1923 1924		/* Ensure that the IRQ handler isn't running on another CPU. */1925		synchronize_irq(uport->irq);1926	}1927}1928 1929static bool uart_carrier_raised(struct tty_port *port)1930{1931	struct uart_state *state = container_of(port, struct uart_state, port);1932	struct uart_port *uport;1933	int mctrl;1934 1935	uport = uart_port_ref(state);1936	/*1937	 * Should never observe uport == NULL since checks for hangup should1938	 * abort the tty_port_block_til_ready() loop before checking for carrier1939	 * raised -- but report carrier raised if it does anyway so open will1940	 * continue and not sleep1941	 */1942	if (WARN_ON(!uport))1943		return true;1944	uart_port_lock_irq(uport);1945	uart_enable_ms(uport);1946	mctrl = uport->ops->get_mctrl(uport);1947	uart_port_unlock_irq(uport);1948	uart_port_deref(uport);1949 1950	return mctrl & TIOCM_CAR;1951}1952 1953static void uart_dtr_rts(struct tty_port *port, bool active)1954{1955	struct uart_state *state = container_of(port, struct uart_state, port);1956	struct uart_port *uport;1957 1958	uport = uart_port_ref(state);1959	if (!uport)1960		return;1961	uart_port_dtr_rts(uport, active);1962	uart_port_deref(uport);1963}1964 1965static int uart_install(struct tty_driver *driver, struct tty_struct *tty)1966{1967	struct uart_driver *drv = driver->driver_state;1968	struct uart_state *state = drv->state + tty->index;1969 1970	tty->driver_data = state;1971 1972	return tty_standard_install(driver, tty);1973}1974 1975/*1976 * Calls to uart_open are serialised by the tty_lock in1977 *   drivers/tty/tty_io.c:tty_open()1978 * Note that if this fails, then uart_close() _will_ be called.1979 *1980 * In time, we want to scrap the "opening nonpresent ports"1981 * behaviour and implement an alternative way for setserial1982 * to set base addresses/ports/types.  This will allow us to1983 * get rid of a certain amount of extra tests.1984 */1985static int uart_open(struct tty_struct *tty, struct file *filp)1986{1987	struct uart_state *state = tty->driver_data;1988	int retval;1989 1990	retval = tty_port_open(&state->port, tty, filp);1991	if (retval > 0)1992		retval = 0;1993 1994	return retval;1995}1996 1997static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)1998{1999	struct uart_state *state = container_of(port, struct uart_state, port);2000	struct uart_port *uport;2001	int ret;2002 2003	uport = uart_port_check(state);2004	if (!uport || uport->flags & UPF_DEAD)2005		return -ENXIO;2006 2007	/*2008	 * Start up the serial port.2009	 */2010	ret = uart_startup(tty, state, false);2011	if (ret > 0)2012		tty_port_set_active(port, true);2013 2014	return ret;2015}2016 2017static const char *uart_type(struct uart_port *port)2018{2019	const char *str = NULL;2020 2021	if (port->ops->type)2022		str = port->ops->type(port);2023 2024	if (!str)2025		str = "unknown";2026 2027	return str;2028}2029 2030#ifdef CONFIG_PROC_FS2031 2032static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)2033{2034	struct uart_state *state = drv->state + i;2035	struct tty_port *port = &state->port;2036	enum uart_pm_state pm_state;2037	struct uart_port *uport;2038	char stat_buf[32];2039	unsigned int status;2040	int mmio;2041 2042	guard(mutex)(&port->mutex);2043 2044	uport = uart_port_check(state);2045	if (!uport)2046		return;2047 2048	mmio = uport->iotype >= UPIO_MEM;2049	seq_printf(m, "%d: uart:%s %s%08llX irq:%d",2050			uport->line, uart_type(uport),2051			mmio ? "mmio:0x" : "port:",2052			mmio ? (unsigned long long)uport->mapbase2053			     : (unsigned long long)uport->iobase,2054			uport->irq);2055 2056	if (uport->type == PORT_UNKNOWN) {2057		seq_putc(m, '\n');2058		return;2059	}2060 2061	if (capable(CAP_SYS_ADMIN)) {2062		pm_state = state->pm_state;2063		if (pm_state != UART_PM_STATE_ON)2064			uart_change_pm(state, UART_PM_STATE_ON);2065		uart_port_lock_irq(uport);2066		status = uport->ops->get_mctrl(uport);2067		uart_port_unlock_irq(uport);2068		if (pm_state != UART_PM_STATE_ON)2069			uart_change_pm(state, pm_state);2070 2071		seq_printf(m, " tx:%d rx:%d",2072				uport->icount.tx, uport->icount.rx);2073		if (uport->icount.frame)2074			seq_printf(m, " fe:%d",	uport->icount.frame);2075		if (uport->icount.parity)2076			seq_printf(m, " pe:%d",	uport->icount.parity);2077		if (uport->icount.brk)2078			seq_printf(m, " brk:%d", uport->icount.brk);2079		if (uport->icount.overrun)2080			seq_printf(m, " oe:%d", uport->icount.overrun);2081		if (uport->icount.buf_overrun)2082			seq_printf(m, " bo:%d", uport->icount.buf_overrun);2083 2084#define INFOBIT(bit, str) \2085	if (uport->mctrl & (bit)) \2086		strncat(stat_buf, (str), sizeof(stat_buf) - \2087			strlen(stat_buf) - 2)2088#define STATBIT(bit, str) \2089	if (status & (bit)) \2090		strncat(stat_buf, (str), sizeof(stat_buf) - \2091		       strlen(stat_buf) - 2)2092 2093		stat_buf[0] = '\0';2094		stat_buf[1] = '\0';2095		INFOBIT(TIOCM_RTS, "|RTS");2096		STATBIT(TIOCM_CTS, "|CTS");2097		INFOBIT(TIOCM_DTR, "|DTR");2098		STATBIT(TIOCM_DSR, "|DSR");2099		STATBIT(TIOCM_CAR, "|CD");2100		STATBIT(TIOCM_RNG, "|RI");2101		if (stat_buf[0])2102			stat_buf[0] = ' ';2103 2104		seq_puts(m, stat_buf);2105	}2106	seq_putc(m, '\n');2107#undef STATBIT2108#undef INFOBIT2109}2110 2111static int uart_proc_show(struct seq_file *m, void *v)2112{2113	struct tty_driver *ttydrv = m->private;2114	struct uart_driver *drv = ttydrv->driver_state;2115	int i;2116 2117	seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");2118	for (i = 0; i < drv->nr; i++)2119		uart_line_info(m, drv, i);2120	return 0;2121}2122#endif2123 2124static void uart_port_spin_lock_init(struct uart_port *port)2125{2126	spin_lock_init(&port->lock);2127	lockdep_set_class(&port->lock, &port_lock_key);2128}2129 2130#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)2131/**2132 * uart_console_write - write a console message to a serial port2133 * @port: the port to write the message2134 * @s: array of characters2135 * @count: number of characters in string to write2136 * @putchar: function to write character to port2137 */2138void uart_console_write(struct uart_port *port, const char *s,2139			unsigned int count,2140			void (*putchar)(struct uart_port *, unsigned char))2141{2142	unsigned int i;2143 2144	for (i = 0; i < count; i++, s++) {2145		if (*s == '\n')2146			putchar(port, '\r');2147		putchar(port, *s);2148	}2149}2150EXPORT_SYMBOL_GPL(uart_console_write);2151 2152/**2153 * uart_get_console - get uart port for console2154 * @ports: ports to search in2155 * @nr: number of @ports2156 * @co: console to search for2157 * Returns: uart_port for the console @co2158 *2159 * Check whether an invalid uart number has been specified (as @co->index), and2160 * if so, search for the first available port that does have console support.2161 */2162struct uart_port * __init2163uart_get_console(struct uart_port *ports, int nr, struct console *co)2164{2165	int idx = co->index;2166 2167	if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&2168				     ports[idx].membase == NULL))2169		for (idx = 0; idx < nr; idx++)2170			if (ports[idx].iobase != 0 ||2171			    ports[idx].membase != NULL)2172				break;2173 2174	co->index = idx;2175 2176	return ports + idx;2177}2178 2179/**2180 * uart_parse_earlycon - Parse earlycon options2181 * @p:	     ptr to 2nd field (ie., just beyond '<name>,')2182 * @iotype:  ptr for decoded iotype (out)2183 * @addr:    ptr for decoded mapbase/iobase (out)2184 * @options: ptr for <options> field; %NULL if not present (out)2185 *2186 * Decodes earlycon kernel command line parameters of the form:2187 *  * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>2188 *  * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>2189 *2190 * The optional form:2191 *  * earlycon=<name>,0x<addr>,<options>2192 *  * console=<name>,0x<addr>,<options>2193 *2194 * is also accepted; the returned @iotype will be %UPIO_MEM.2195 *2196 * Returns: 0 on success or -%EINVAL on failure2197 */2198int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,2199			char **options)2200{2201	if (strncmp(p, "mmio,", 5) == 0) {2202		*iotype = UPIO_MEM;2203		p += 5;2204	} else if (strncmp(p, "mmio16,", 7) == 0) {2205		*iotype = UPIO_MEM16;2206		p += 7;2207	} else if (strncmp(p, "mmio32,", 7) == 0) {2208		*iotype = UPIO_MEM32;2209		p += 7;2210	} else if (strncmp(p, "mmio32be,", 9) == 0) {2211		*iotype = UPIO_MEM32BE;2212		p += 9;2213	} else if (strncmp(p, "mmio32native,", 13) == 0) {2214		*iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?2215			UPIO_MEM32BE : UPIO_MEM32;2216		p += 13;2217	} else if (strncmp(p, "io,", 3) == 0) {2218		*iotype = UPIO_PORT;2219		p += 3;2220	} else if (strncmp(p, "0x", 2) == 0) {2221		*iotype = UPIO_MEM;2222	} else {2223		return -EINVAL;2224	}2225 2226	/*2227	 * Before you replace it with kstrtoull(), think about options separator2228	 * (',') it will not tolerate2229	 */2230	*addr = simple_strtoull(p, NULL, 0);2231	p = strchr(p, ',');2232	if (p)2233		p++;2234 2235	*options = p;2236	return 0;2237}2238EXPORT_SYMBOL_GPL(uart_parse_earlycon);2239 2240/**2241 * uart_parse_options - Parse serial port baud/parity/bits/flow control.2242 * @options: pointer to option string2243 * @baud: pointer to an 'int' variable for the baud rate.2244 * @parity: pointer to an 'int' variable for the parity.2245 * @bits: pointer to an 'int' variable for the number of data bits.2246 * @flow: pointer to an 'int' variable for the flow control character.2247 *2248 * uart_parse_options() decodes a string containing the serial console2249 * options. The format of the string is <baud><parity><bits><flow>,2250 * eg: 115200n8r2251 */2252void2253uart_parse_options(const char *options, int *baud, int *parity,2254		   int *bits, int *flow)2255{2256	const char *s = options;2257 2258	*baud = simple_strtoul(s, NULL, 10);2259	while (*s >= '0' && *s <= '9')2260		s++;2261	if (*s)2262		*parity = *s++;2263	if (*s)2264		*bits = *s++ - '0';2265	if (*s)2266		*flow = *s;2267}2268EXPORT_SYMBOL_GPL(uart_parse_options);2269 2270/**2271 * uart_set_options - setup the serial console parameters2272 * @port: pointer to the serial ports uart_port structure2273 * @co: console pointer2274 * @baud: baud rate2275 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)2276 * @bits: number of data bits2277 * @flow: flow control character - 'r' (rts)2278 *2279 * Locking: Caller must hold console_list_lock in order to serialize2280 * early initialization of the serial-console lock.2281 */2282int2283uart_set_options(struct uart_port *port, struct console *co,2284		 int baud, int parity, int bits, int flow)2285{2286	struct ktermios termios;2287	static struct ktermios dummy;2288 2289	/*2290	 * Ensure that the serial-console lock is initialised early.2291	 *2292	 * Note that the console-registered check is needed because2293	 * kgdboc can call uart_set_options() for an already registered2294	 * console via tty_find_polling_driver() and uart_poll_init().2295	 */2296	if (!uart_console_registered_locked(port) && !port->console_reinit)2297		uart_port_spin_lock_init(port);2298 2299	memset(&termios, 0, sizeof(struct ktermios));2300 2301	termios.c_cflag |= CREAD | HUPCL | CLOCAL;2302	tty_termios_encode_baud_rate(&termios, baud, baud);2303 2304	if (bits == 7)2305		termios.c_cflag |= CS7;2306	else2307		termios.c_cflag |= CS8;2308 2309	switch (parity) {2310	case 'o': case 'O':2311		termios.c_cflag |= PARODD;2312		fallthrough;2313	case 'e': case 'E':2314		termios.c_cflag |= PARENB;2315		break;2316	}2317 2318	if (flow == 'r')2319		termios.c_cflag |= CRTSCTS;2320 2321	/*2322	 * some uarts on other side don't support no flow control.2323	 * So we set * DTR in host uart to make them happy2324	 */2325	port->mctrl |= TIOCM_DTR;2326 2327	port->ops->set_termios(port, &termios, &dummy);2328	/*2329	 * Allow the setting of the UART parameters with a NULL console2330	 * too:2331	 */2332	if (co) {2333		co->cflag = termios.c_cflag;2334		co->ispeed = termios.c_ispeed;2335		co->ospeed = termios.c_ospeed;2336	}2337 2338	return 0;2339}2340EXPORT_SYMBOL_GPL(uart_set_options);2341#endif /* CONFIG_SERIAL_CORE_CONSOLE */2342 2343/**2344 * uart_change_pm - set power state of the port2345 *2346 * @state: port descriptor2347 * @pm_state: new state2348 *2349 * Locking: port->mutex has to be held2350 */2351static void uart_change_pm(struct uart_state *state,2352			   enum uart_pm_state pm_state)2353{2354	struct uart_port *port = uart_port_check(state);2355 2356	if (state->pm_state != pm_state) {2357		if (port && port->ops->pm)2358			port->ops->pm(port, pm_state, state->pm_state);2359		state->pm_state = pm_state;2360	}2361}2362 2363struct uart_match {2364	struct uart_port *port;2365	struct uart_driver *driver;2366};2367 2368static int serial_match_port(struct device *dev, void *data)2369{2370	struct uart_match *match = data;2371	struct tty_driver *tty_drv = match->driver->tty_driver;2372	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +2373		match->port->line;2374 2375	return dev->devt == devt; /* Actually, only one tty per port */2376}2377 2378int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)2379{2380	struct uart_state *state = drv->state + uport->line;2381	struct tty_port *port = &state->port;2382	struct device *tty_dev;2383	struct uart_match match = {uport, drv};2384 2385	guard(mutex)(&port->mutex);2386 2387	tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);2388	if (tty_dev && device_may_wakeup(tty_dev)) {2389		enable_irq_wake(uport->irq);2390		put_device(tty_dev);2391		return 0;2392	}2393	put_device(tty_dev);2394 2395	/*2396	 * Nothing to do if the console is not suspending2397	 * except stop_rx to prevent any asynchronous data2398	 * over RX line. However ensure that we will be2399	 * able to Re-start_rx later.2400	 */2401	if (!console_suspend_enabled && uart_console(uport)) {2402		if (uport->ops->start_rx) {2403			uart_port_lock_irq(uport);2404			uport->ops->stop_rx(uport);2405			uart_port_unlock_irq(uport);2406		}2407		device_set_awake_path(uport->dev);2408		return 0;2409	}2410 2411	uport->suspended = 1;2412 2413	if (tty_port_initialized(port)) {2414		const struct uart_ops *ops = uport->ops;2415		int tries;2416		unsigned int mctrl;2417 2418		tty_port_set_suspended(port, true);2419		tty_port_set_initialized(port, false);2420 2421		uart_port_lock_irq(uport);2422		ops->stop_tx(uport);2423		if (!(uport->rs485.flags & SER_RS485_ENABLED))2424			ops->set_mctrl(uport, 0);2425		/* save mctrl so it can be restored on resume */2426		mctrl = uport->mctrl;2427		uport->mctrl = 0;2428		ops->stop_rx(uport);2429		uart_port_unlock_irq(uport);2430 2431		/*2432		 * Wait for the transmitter to empty.2433		 */2434		for (tries = 3; !ops->tx_empty(uport) && tries; tries--)2435			msleep(10);2436		if (!tries)2437			dev_err(uport->dev, "%s: Unable to drain transmitter\n",2438				uport->name);2439 2440		ops->shutdown(uport);2441		uport->mctrl = mctrl;2442	}2443 2444	/*2445	 * Disable the console device before suspending.2446	 */2447	if (uart_console(uport))2448		console_stop(uport->cons);2449 2450	uart_change_pm(state, UART_PM_STATE_OFF);2451 2452	return 0;2453}2454EXPORT_SYMBOL(uart_suspend_port);2455 2456int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)2457{2458	struct uart_state *state = drv->state + uport->line;2459	struct tty_port *port = &state->port;2460	struct device *tty_dev;2461	struct uart_match match = {uport, drv};2462	struct ktermios termios;2463 2464	guard(mutex)(&port->mutex);2465 2466	tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);2467	if (!uport->suspended && device_may_wakeup(tty_dev)) {2468		if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))2469			disable_irq_wake(uport->irq);2470		put_device(tty_dev);2471		return 0;2472	}2473	put_device(tty_dev);2474	uport->suspended = 0;2475 2476	/*2477	 * Re-enable the console device after suspending.2478	 */2479	if (uart_console(uport)) {2480		/*2481		 * First try to use the console cflag setting.2482		 */2483		memset(&termios, 0, sizeof(struct ktermios));2484		termios.c_cflag = uport->cons->cflag;2485		termios.c_ispeed = uport->cons->ispeed;2486		termios.c_ospeed = uport->cons->ospeed;2487 2488		/*2489		 * If that's unset, use the tty termios setting.2490		 */2491		if (port->tty && termios.c_cflag == 0)2492			termios = port->tty->termios;2493 2494		if (console_suspend_enabled)2495			uart_change_pm(state, UART_PM_STATE_ON);2496		uport->ops->set_termios(uport, &termios, NULL);2497		if (!console_suspend_enabled && uport->ops->start_rx) {2498			uart_port_lock_irq(uport);2499			uport->ops->start_rx(uport);2500			uart_port_unlock_irq(uport);2501		}2502		if (console_suspend_enabled)2503			console_start(uport->cons);2504	}2505 2506	if (tty_port_suspended(port)) {2507		const struct uart_ops *ops = uport->ops;2508		int ret;2509 2510		uart_change_pm(state, UART_PM_STATE_ON);2511		uart_port_lock_irq(uport);2512		if (!(uport->rs485.flags & SER_RS485_ENABLED))2513			ops->set_mctrl(uport, 0);2514		uart_port_unlock_irq(uport);2515		if (console_suspend_enabled || !uart_console(uport)) {2516			/* Protected by port mutex for now */2517			struct tty_struct *tty = port->tty;2518 2519			ret = ops->startup(uport);2520			if (ret == 0) {2521				if (tty)2522					uart_change_line_settings(tty, state, NULL);2523				uart_rs485_config(uport);2524				uart_port_lock_irq(uport);2525				if (!(uport->rs485.flags & SER_RS485_ENABLED))2526					ops->set_mctrl(uport, uport->mctrl);2527				ops->start_tx(uport);2528				uart_port_unlock_irq(uport);2529				tty_port_set_initialized(port, true);2530			} else {2531				/*2532				 * Failed to resume - maybe hardware went away?2533				 * Clear the "initialized" flag so we won't try2534				 * to call the low level drivers shutdown method.2535				 */2536				uart_shutdown(tty, state);2537			}2538		}2539 2540		tty_port_set_suspended(port, false);2541	}2542 2543	return 0;2544}2545EXPORT_SYMBOL(uart_resume_port);2546 2547static inline void2548uart_report_port(struct uart_driver *drv, struct uart_port *port)2549{2550	char address[64];2551 2552	switch (port->iotype) {2553	case UPIO_PORT:2554		snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);2555		break;2556	case UPIO_HUB6:2557		snprintf(address, sizeof(address),2558			 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);2559		break;2560	case UPIO_MEM:2561	case UPIO_MEM16:2562	case UPIO_MEM32:2563	case UPIO_MEM32BE:2564	case UPIO_AU:2565	case UPIO_TSI:2566		snprintf(address, sizeof(address),2567			 "MMIO 0x%llx", (unsigned long long)port->mapbase);2568		break;2569	default:2570		strscpy(address, "*unknown*", sizeof(address));2571		break;2572	}2573 2574	pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",2575	       port->dev ? dev_name(port->dev) : "",2576	       port->dev ? ": " : "",2577	       port->name,2578	       address, port->irq, port->uartclk / 16, uart_type(port));2579 2580	/* The magic multiplier feature is a bit obscure, so report it too.  */2581	if (port->flags & UPF_MAGIC_MULTIPLIER)2582		pr_info("%s%s%s extra baud rates supported: %d, %d",2583			port->dev ? dev_name(port->dev) : "",2584			port->dev ? ": " : "",2585			port->name,2586			port->uartclk / 8, port->uartclk / 4);2587}2588 2589static void2590uart_configure_port(struct uart_driver *drv, struct uart_state *state,2591		    struct uart_port *port)2592{2593	unsigned int flags;2594 2595	/*2596	 * If there isn't a port here, don't do anything further.2597	 */2598	if (!port->iobase && !port->mapbase && !port->membase)2599		return;2600 2601	/*2602	 * Now do the auto configuration stuff.  Note that config_port2603	 * is expected to claim the resources and map the port for us.2604	 */2605	flags = 0;2606	if (port->flags & UPF_AUTO_IRQ)2607		flags |= UART_CONFIG_IRQ;2608	if (port->flags & UPF_BOOT_AUTOCONF) {2609		if (!(port->flags & UPF_FIXED_TYPE)) {2610			port->type = PORT_UNKNOWN;2611			flags |= UART_CONFIG_TYPE;2612		}2613		/* Synchronize with possible boot console. */2614		if (uart_console(port))2615			console_lock();2616		port->ops->config_port(port, flags);2617		if (uart_console(port))2618			console_unlock();2619	}2620 2621	if (port->type != PORT_UNKNOWN) {2622		unsigned long flags;2623 2624		uart_report_port(drv, port);2625 2626		/* Synchronize with possible boot console. */2627		if (uart_console(port))2628			console_lock();2629 2630		/* Power up port for set_mctrl() */2631		uart_change_pm(state, UART_PM_STATE_ON);2632 2633		/*2634		 * Ensure that the modem control lines are de-activated.2635		 * keep the DTR setting that is set in uart_set_options()2636		 * We probably don't need a spinlock around this, but2637		 */2638		uart_port_lock_irqsave(port, &flags);2639		port->mctrl &= TIOCM_DTR;2640		if (!(port->rs485.flags & SER_RS485_ENABLED))2641			port->ops->set_mctrl(port, port->mctrl);2642		uart_port_unlock_irqrestore(port, flags);2643 2644		uart_rs485_config(port);2645 2646		if (uart_console(port))2647			console_unlock();2648 2649		/*2650		 * If this driver supports console, and it hasn't been2651		 * successfully registered yet, try to re-register it.2652		 * It may be that the port was not available.2653		 */2654		if (port->cons && !console_is_registered(port->cons))2655			register_console(port->cons);2656 2657		/*2658		 * Power down all ports by default, except the2659		 * console if we have one.2660		 */2661		if (!uart_console(port))2662			uart_change_pm(state, UART_PM_STATE_OFF);2663	}2664}2665 2666#ifdef CONFIG_CONSOLE_POLL2667 2668static int uart_poll_init(struct tty_driver *driver, int line, char *options)2669{2670	struct uart_driver *drv = driver->driver_state;2671	struct uart_state *state = drv->state + line;2672	enum uart_pm_state pm_state;2673	struct tty_port *tport;2674	struct uart_port *port;2675	int baud = 9600;2676	int bits = 8;2677	int parity = 'n';2678	int flow = 'n';2679	int ret = 0;2680 2681	tport = &state->port;2682 2683	guard(mutex)(&tport->mutex);2684 2685	port = uart_port_check(state);2686	if (!port || port->type == PORT_UNKNOWN ||2687	    !(port->ops->poll_get_char && port->ops->poll_put_char))2688		return -1;2689 2690	pm_state = state->pm_state;2691	uart_change_pm(state, UART_PM_STATE_ON);2692 2693	if (port->ops->poll_init) {2694		/*2695		 * We don't set initialized as we only initialized the hw,2696		 * e.g. state->xmit is still uninitialized.2697		 */2698		if (!tty_port_initialized(tport))2699			ret = port->ops->poll_init(port);2700	}2701 2702	if (!ret && options) {2703		uart_parse_options(options, &baud, &parity, &bits, &flow);2704		console_list_lock();2705		ret = uart_set_options(port, NULL, baud, parity, bits, flow);2706		console_list_unlock();2707	}2708 2709	if (ret)2710		uart_change_pm(state, pm_state);2711 2712	return ret;2713}2714 2715static int uart_poll_get_char(struct tty_driver *driver, int line)2716{2717	struct uart_driver *drv = driver->driver_state;2718	struct uart_state *state = drv->state + line;2719	struct uart_port *port;2720	int ret = -1;2721 2722	port = uart_port_ref(state);2723	if (port) {2724		ret = port->ops->poll_get_char(port);2725		uart_port_deref(port);2726	}2727 2728	return ret;2729}2730 2731static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)2732{2733	struct uart_driver *drv = driver->driver_state;2734	struct uart_state *state = drv->state + line;2735	struct uart_port *port;2736 2737	port = uart_port_ref(state);2738	if (!port)2739		return;2740 2741	if (ch == '\n')2742		port->ops->poll_put_char(port, '\r');2743	port->ops->poll_put_char(port, ch);2744	uart_port_deref(port);2745}2746#endif2747 2748static const struct tty_operations uart_ops = {2749	.install	= uart_install,2750	.open		= uart_open,2751	.close		= uart_close,2752	.write		= uart_write,2753	.put_char	= uart_put_char,2754	.flush_chars	= uart_flush_chars,2755	.write_room	= uart_write_room,2756	.chars_in_buffer= uart_chars_in_buffer,2757	.flush_buffer	= uart_flush_buffer,2758	.ioctl		= uart_ioctl,2759	.throttle	= uart_throttle,2760	.unthrottle	= uart_unthrottle,2761	.send_xchar	= uart_send_xchar,2762	.set_termios	= uart_set_termios,2763	.set_ldisc	= uart_set_ldisc,2764	.stop		= uart_stop,2765	.start		= uart_start,2766	.hangup		= uart_hangup,2767	.break_ctl	= uart_break_ctl,2768	.wait_until_sent= uart_wait_until_sent,2769#ifdef CONFIG_PROC_FS2770	.proc_show	= uart_proc_show,2771#endif2772	.tiocmget	= uart_tiocmget,2773	.tiocmset	= uart_tiocmset,2774	.set_serial	= uart_set_info_user,2775	.get_serial	= uart_get_info_user,2776	.get_icount	= uart_get_icount,2777#ifdef CONFIG_CONSOLE_POLL2778	.poll_init	= uart_poll_init,2779	.poll_get_char	= uart_poll_get_char,2780	.poll_put_char	= uart_poll_put_char,2781#endif2782};2783 2784static const struct tty_port_operations uart_port_ops = {2785	.carrier_raised = uart_carrier_raised,2786	.dtr_rts	= uart_dtr_rts,2787	.activate	= uart_port_activate,2788	.shutdown	= uart_tty_port_shutdown,2789};2790 2791/**2792 * uart_register_driver - register a driver with the uart core layer2793 * @drv: low level driver structure2794 *2795 * Register a uart driver with the core driver. We in turn register with the2796 * tty layer, and initialise the core driver per-port state.2797 *2798 * We have a proc file in /proc/tty/driver which is named after the normal2799 * driver.2800 *2801 * @drv->port should be %NULL, and the per-port structures should be registered2802 * using uart_add_one_port() after this call has succeeded.2803 *2804 * Locking: none, Interrupts: enabled2805 */2806int uart_register_driver(struct uart_driver *drv)2807{2808	struct tty_driver *normal;2809	int i, retval = -ENOMEM;2810 2811	BUG_ON(drv->state);2812 2813	/*2814	 * Maybe we should be using a slab cache for this, especially if2815	 * we have a large number of ports to handle.2816	 */2817	drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);2818	if (!drv->state)2819		goto out;2820 2821	normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |2822			TTY_DRIVER_DYNAMIC_DEV);2823	if (IS_ERR(normal)) {2824		retval = PTR_ERR(normal);2825		goto out_kfree;2826	}2827 2828	drv->tty_driver = normal;2829 2830	normal->driver_name	= drv->driver_name;2831	normal->name		= drv->dev_name;2832	normal->major		= drv->major;2833	normal->minor_start	= drv->minor;2834	normal->type		= TTY_DRIVER_TYPE_SERIAL;2835	normal->subtype		= SERIAL_TYPE_NORMAL;2836	normal->init_termios	= tty_std_termios;2837	normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;2838	normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;2839	normal->driver_state    = drv;2840	tty_set_operations(normal, &uart_ops);2841 2842	/*2843	 * Initialise the UART state(s).2844	 */2845	for (i = 0; i < drv->nr; i++) {2846		struct uart_state *state = drv->state + i;2847		struct tty_port *port = &state->port;2848 2849		tty_port_init(port);2850		port->ops = &uart_port_ops;2851	}2852 2853	retval = tty_register_driver(normal);2854	if (retval >= 0)2855		return retval;2856 2857	for (i = 0; i < drv->nr; i++)2858		tty_port_destroy(&drv->state[i].port);2859	tty_driver_kref_put(normal);2860out_kfree:2861	kfree(drv->state);2862out:2863	return retval;2864}2865EXPORT_SYMBOL(uart_register_driver);2866 2867/**2868 * uart_unregister_driver - remove a driver from the uart core layer2869 * @drv: low level driver structure2870 *2871 * Remove all references to a driver from the core driver. The low level2872 * driver must have removed all its ports via the uart_remove_one_port() if it2873 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)2874 *2875 * Locking: none, Interrupts: enabled2876 */2877void uart_unregister_driver(struct uart_driver *drv)2878{2879	struct tty_driver *p = drv->tty_driver;2880	unsigned int i;2881 2882	tty_unregister_driver(p);2883	tty_driver_kref_put(p);2884	for (i = 0; i < drv->nr; i++)2885		tty_port_destroy(&drv->state[i].port);2886	kfree(drv->state);2887	drv->state = NULL;2888	drv->tty_driver = NULL;2889}2890EXPORT_SYMBOL(uart_unregister_driver);2891 2892struct tty_driver *uart_console_device(struct console *co, int *index)2893{2894	struct uart_driver *p = co->data;2895	*index = co->index;2896	return p->tty_driver;2897}2898EXPORT_SYMBOL_GPL(uart_console_device);2899 2900static ssize_t uartclk_show(struct device *dev,2901	struct device_attribute *attr, char *buf)2902{2903	struct serial_struct tmp;2904	struct tty_port *port = dev_get_drvdata(dev);2905 2906	uart_get_info(port, &tmp);2907	return sprintf(buf, "%d\n", tmp.baud_base * 16);2908}2909 2910static ssize_t type_show(struct device *dev,2911	struct device_attribute *attr, char *buf)2912{2913	struct serial_struct tmp;2914	struct tty_port *port = dev_get_drvdata(dev);2915 2916	uart_get_info(port, &tmp);2917	return sprintf(buf, "%d\n", tmp.type);2918}2919 2920static ssize_t line_show(struct device *dev,2921	struct device_attribute *attr, char *buf)2922{2923	struct serial_struct tmp;2924	struct tty_port *port = dev_get_drvdata(dev);2925 2926	uart_get_info(port, &tmp);2927	return sprintf(buf, "%d\n", tmp.line);2928}2929 2930static ssize_t port_show(struct device *dev,2931	struct device_attribute *attr, char *buf)2932{2933	struct serial_struct tmp;2934	struct tty_port *port = dev_get_drvdata(dev);2935	unsigned long ioaddr;2936 2937	uart_get_info(port, &tmp);2938	ioaddr = tmp.port;2939	if (HIGH_BITS_OFFSET)2940		ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;2941	return sprintf(buf, "0x%lX\n", ioaddr);2942}2943 2944static ssize_t irq_show(struct device *dev,2945	struct device_attribute *attr, char *buf)2946{2947	struct serial_struct tmp;2948	struct tty_port *port = dev_get_drvdata(dev);2949 2950	uart_get_info(port, &tmp);2951	return sprintf(buf, "%d\n", tmp.irq);2952}2953 2954static ssize_t flags_show(struct device *dev,2955	struct device_attribute *attr, char *buf)2956{2957	struct serial_struct tmp;2958	struct tty_port *port = dev_get_drvdata(dev);2959 2960	uart_get_info(port, &tmp);2961	return sprintf(buf, "0x%X\n", tmp.flags);2962}2963 2964static ssize_t xmit_fifo_size_show(struct device *dev,2965	struct device_attribute *attr, char *buf)2966{2967	struct serial_struct tmp;2968	struct tty_port *port = dev_get_drvdata(dev);2969 2970	uart_get_info(port, &tmp);2971	return sprintf(buf, "%d\n", tmp.xmit_fifo_size);2972}2973 2974static ssize_t close_delay_show(struct device *dev,2975	struct device_attribute *attr, char *buf)2976{2977	struct serial_struct tmp;2978	struct tty_port *port = dev_get_drvdata(dev);2979 2980	uart_get_info(port, &tmp);2981	return sprintf(buf, "%d\n", tmp.close_delay);2982}2983 2984static ssize_t closing_wait_show(struct device *dev,2985	struct device_attribute *attr, char *buf)2986{2987	struct serial_struct tmp;2988	struct tty_port *port = dev_get_drvdata(dev);2989 2990	uart_get_info(port, &tmp);2991	return sprintf(buf, "%d\n", tmp.closing_wait);2992}2993 2994static ssize_t custom_divisor_show(struct device *dev,2995	struct device_attribute *attr, char *buf)2996{2997	struct serial_struct tmp;2998	struct tty_port *port = dev_get_drvdata(dev);2999 3000	uart_get_info(port, &tmp);3001	return sprintf(buf, "%d\n", tmp.custom_divisor);3002}3003 3004static ssize_t io_type_show(struct device *dev,3005	struct device_attribute *attr, char *buf)3006{3007	struct serial_struct tmp;3008	struct tty_port *port = dev_get_drvdata(dev);3009 3010	uart_get_info(port, &tmp);3011	return sprintf(buf, "%d\n", tmp.io_type);3012}3013 3014static ssize_t iomem_base_show(struct device *dev,3015	struct device_attribute *attr, char *buf)3016{3017	struct serial_struct tmp;3018	struct tty_port *port = dev_get_drvdata(dev);3019 3020	uart_get_info(port, &tmp);3021	return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);3022}3023 3024static ssize_t iomem_reg_shift_show(struct device *dev,3025	struct device_attribute *attr, char *buf)3026{3027	struct serial_struct tmp;3028	struct tty_port *port = dev_get_drvdata(dev);3029 3030	uart_get_info(port, &tmp);3031	return sprintf(buf, "%d\n", tmp.iomem_reg_shift);3032}3033 3034static ssize_t console_show(struct device *dev,3035	struct device_attribute *attr, char *buf)3036{3037	struct tty_port *port = dev_get_drvdata(dev);3038	struct uart_state *state = container_of(port, struct uart_state, port);3039	struct uart_port *uport;3040	bool console = false;3041 3042	mutex_lock(&port->mutex);3043	uport = uart_port_check(state);3044	if (uport)3045		console = uart_console_registered(uport);3046	mutex_unlock(&port->mutex);3047 3048	return sprintf(buf, "%c\n", console ? 'Y' : 'N');3049}3050 3051static ssize_t console_store(struct device *dev,3052	struct device_attribute *attr, const char *buf, size_t count)3053{3054	struct tty_port *port = dev_get_drvdata(dev);3055	struct uart_state *state = container_of(port, struct uart_state, port);3056	struct uart_port *uport;3057	bool oldconsole, newconsole;3058	int ret;3059 3060	ret = kstrtobool(buf, &newconsole);3061	if (ret)3062		return ret;3063 3064	mutex_lock(&port->mutex);3065	uport = uart_port_check(state);3066	if (uport) {3067		oldconsole = uart_console_registered(uport);3068		if (oldconsole && !newconsole) {3069			ret = unregister_console(uport->cons);3070		} else if (!oldconsole && newconsole) {3071			if (uart_console(uport)) {3072				uport->console_reinit = 1;3073				register_console(uport->cons);3074			} else {3075				ret = -ENOENT;3076			}3077		}3078	} else {3079		ret = -ENXIO;3080	}3081	mutex_unlock(&port->mutex);3082 3083	return ret < 0 ? ret : count;3084}3085 3086static DEVICE_ATTR_RO(uartclk);3087static DEVICE_ATTR_RO(type);3088static DEVICE_ATTR_RO(line);3089static DEVICE_ATTR_RO(port);3090static DEVICE_ATTR_RO(irq);3091static DEVICE_ATTR_RO(flags);3092static DEVICE_ATTR_RO(xmit_fifo_size);3093static DEVICE_ATTR_RO(close_delay);3094static DEVICE_ATTR_RO(closing_wait);3095static DEVICE_ATTR_RO(custom_divisor);3096static DEVICE_ATTR_RO(io_type);3097static DEVICE_ATTR_RO(iomem_base);3098static DEVICE_ATTR_RO(iomem_reg_shift);3099static DEVICE_ATTR_RW(console);3100 3101static struct attribute *tty_dev_attrs[] = {3102	&dev_attr_uartclk.attr,3103	&dev_attr_type.attr,3104	&dev_attr_line.attr,3105	&dev_attr_port.attr,3106	&dev_attr_irq.attr,3107	&dev_attr_flags.attr,3108	&dev_attr_xmit_fifo_size.attr,3109	&dev_attr_close_delay.attr,3110	&dev_attr_closing_wait.attr,3111	&dev_attr_custom_divisor.attr,3112	&dev_attr_io_type.attr,3113	&dev_attr_iomem_base.attr,3114	&dev_attr_iomem_reg_shift.attr,3115	&dev_attr_console.attr,3116	NULL3117};3118 3119static const struct attribute_group tty_dev_attr_group = {3120	.attrs = tty_dev_attrs,3121};3122 3123/**3124 * serial_core_add_one_port - attach a driver-defined port structure3125 * @drv: pointer to the uart low level driver structure for this port3126 * @uport: uart port structure to use for this port.3127 *3128 * Context: task context, might sleep3129 *3130 * This allows the driver @drv to register its own uart_port structure with the3131 * core driver. The main purpose is to allow the low level uart drivers to3132 * expand uart_port, rather than having yet more levels of structures.3133 * Caller must hold port_mutex.3134 */3135static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)3136{3137	struct uart_state *state;3138	struct tty_port *port;3139	int ret = 0;3140	struct device *tty_dev;3141	int num_groups;3142 3143	if (uport->line >= drv->nr)3144		return -EINVAL;3145 3146	state = drv->state + uport->line;3147	port = &state->port;3148 3149	mutex_lock(&port->mutex);3150	if (state->uart_port) {3151		ret = -EINVAL;3152		goto out;3153	}3154 3155	/* Link the port to the driver state table and vice versa */3156	atomic_set(&state->refcount, 1);3157	init_waitqueue_head(&state->remove_wait);3158	state->uart_port = uport;3159	uport->state = state;3160 3161	/*3162	 * If this port is in use as a console then the spinlock is already3163	 * initialised.3164	 */3165	if (!uart_console_registered(uport))3166		uart_port_spin_lock_init(uport);3167 3168	state->pm_state = UART_PM_STATE_UNDEFINED;3169	uart_port_set_cons(uport, drv->cons);3170	uport->minor = drv->tty_driver->minor_start + uport->line;3171	uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,3172				drv->tty_driver->name_base + uport->line);3173	if (!uport->name) {3174		ret = -ENOMEM;3175		goto out;3176	}3177 3178	if (uport->cons && uport->dev)3179		of_console_check(uport->dev->of_node, uport->cons->name, uport->line);3180 3181	tty_port_link_device(port, drv->tty_driver, uport->line);3182	uart_configure_port(drv, state, uport);3183 3184	port->console = uart_console(uport);3185 3186	num_groups = 2;3187	if (uport->attr_group)3188		num_groups++;3189 3190	uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),3191				    GFP_KERNEL);3192	if (!uport->tty_groups) {3193		ret = -ENOMEM;3194		goto out;3195	}3196	uport->tty_groups[0] = &tty_dev_attr_group;3197	if (uport->attr_group)3198		uport->tty_groups[1] = uport->attr_group;3199 3200	/* Ensure serdev drivers can call serdev_device_open() right away */3201	uport->flags &= ~UPF_DEAD;3202 3203	/*3204	 * Register the port whether it's detected or not.  This allows3205	 * setserial to be used to alter this port's parameters.3206	 */3207	tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,3208			uport->line, uport->dev, &uport->port_dev->dev, port,3209			uport->tty_groups);3210	if (!IS_ERR(tty_dev)) {3211		device_set_wakeup_capable(tty_dev, 1);3212	} else {3213		uport->flags |= UPF_DEAD;3214		dev_err(uport->dev, "Cannot register tty device on line %d\n",3215		       uport->line);3216	}3217 3218 out:3219	mutex_unlock(&port->mutex);3220 3221	return ret;3222}3223 3224/**3225 * serial_core_remove_one_port - detach a driver defined port structure3226 * @drv: pointer to the uart low level driver structure for this port3227 * @uport: uart port structure for this port3228 *3229 * Context: task context, might sleep3230 *3231 * This unhooks (and hangs up) the specified port structure from the core3232 * driver. No further calls will be made to the low-level code for this port.3233 * Caller must hold port_mutex.3234 */3235static void serial_core_remove_one_port(struct uart_driver *drv,3236					struct uart_port *uport)3237{3238	struct uart_state *state = drv->state + uport->line;3239	struct tty_port *port = &state->port;3240	struct uart_port *uart_port;3241	struct tty_struct *tty;3242 3243	mutex_lock(&port->mutex);3244	uart_port = uart_port_check(state);3245	if (uart_port != uport)3246		dev_alert(uport->dev, "Removing wrong port: %p != %p\n",3247			  uart_port, uport);3248 3249	if (!uart_port) {3250		mutex_unlock(&port->mutex);3251		return;3252	}3253	mutex_unlock(&port->mutex);3254 3255	/*3256	 * Remove the devices from the tty layer3257	 */3258	tty_port_unregister_device(port, drv->tty_driver, uport->line);3259 3260	tty = tty_port_tty_get(port);3261	if (tty) {3262		tty_vhangup(port->tty);3263		tty_kref_put(tty);3264	}3265 3266	/*3267	 * If the port is used as a console, unregister it3268	 */3269	if (uart_console(uport))3270		unregister_console(uport->cons);3271 3272	/*3273	 * Free the port IO and memory resources, if any.3274	 */3275	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)3276		uport->ops->release_port(uport);3277	kfree(uport->tty_groups);3278	kfree(uport->name);3279 3280	/*3281	 * Indicate that there isn't a port here anymore.3282	 */3283	uport->type = PORT_UNKNOWN;3284	uport->port_dev = NULL;3285 3286	mutex_lock(&port->mutex);3287	WARN_ON(atomic_dec_return(&state->refcount) < 0);3288	wait_event(state->remove_wait, !atomic_read(&state->refcount));3289	state->uart_port = NULL;3290	mutex_unlock(&port->mutex);3291}3292 3293/**3294 * uart_match_port - are the two ports equivalent?3295 * @port1: first port3296 * @port2: second port3297 *3298 * This utility function can be used to determine whether two uart_port3299 * structures describe the same port.3300 */3301bool uart_match_port(const struct uart_port *port1,3302		const struct uart_port *port2)3303{3304	if (port1->iotype != port2->iotype)3305		return false;3306 3307	switch (port1->iotype) {3308	case UPIO_PORT:3309		return port1->iobase == port2->iobase;3310	case UPIO_HUB6:3311		return port1->iobase == port2->iobase &&3312		       port1->hub6   == port2->hub6;3313	case UPIO_MEM:3314	case UPIO_MEM16:3315	case UPIO_MEM32:3316	case UPIO_MEM32BE:3317	case UPIO_AU:3318	case UPIO_TSI:3319		return port1->mapbase == port2->mapbase;3320	}3321 3322	return false;3323}3324EXPORT_SYMBOL(uart_match_port);3325 3326static struct serial_ctrl_device *3327serial_core_get_ctrl_dev(struct serial_port_device *port_dev)3328{3329	struct device *dev = &port_dev->dev;3330 3331	return to_serial_base_ctrl_device(dev->parent);3332}3333 3334/*3335 * Find a registered serial core controller device if one exists. Returns3336 * the first device matching the ctrl_id. Caller must hold port_mutex.3337 */3338static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,3339							struct device *phys_dev,3340							int ctrl_id)3341{3342	struct uart_state *state;3343	int i;3344 3345	lockdep_assert_held(&port_mutex);3346 3347	for (i = 0; i < drv->nr; i++) {3348		state = drv->state + i;3349		if (!state->uart_port || !state->uart_port->port_dev)3350			continue;3351 3352		if (state->uart_port->dev == phys_dev &&3353		    state->uart_port->ctrl_id == ctrl_id)3354			return serial_core_get_ctrl_dev(state->uart_port->port_dev);3355	}3356 3357	return NULL;3358}3359 3360static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)3361{3362	return serial_base_ctrl_add(port, port->dev);3363}3364 3365static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,3366				       struct uart_port *port)3367{3368	struct serial_port_device *port_dev;3369 3370	port_dev = serial_base_port_add(port, ctrl_dev);3371	if (IS_ERR(port_dev))3372		return PTR_ERR(port_dev);3373 3374	port->port_dev = port_dev;3375 3376	return 0;3377}3378 3379/*3380 * Initialize a serial core port device, and a controller device if needed.3381 */3382int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)3383{3384	struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;3385	int ret;3386 3387	mutex_lock(&port_mutex);3388 3389	/*3390	 * Prevent serial_port_runtime_resume() from trying to use the port3391	 * until serial_core_add_one_port() has completed3392	 */3393	port->flags |= UPF_DEAD;3394 3395	/* Inititalize a serial core controller device if needed */3396	ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);3397	if (!ctrl_dev) {3398		new_ctrl_dev = serial_core_ctrl_device_add(port);3399		if (IS_ERR(new_ctrl_dev)) {3400			ret = PTR_ERR(new_ctrl_dev);3401			goto err_unlock;3402		}3403		ctrl_dev = new_ctrl_dev;3404	}3405 3406	/*3407	 * Initialize a serial core port device. Tag the port dead to prevent3408	 * serial_port_runtime_resume() trying to do anything until port has3409	 * been registered. It gets cleared by serial_core_add_one_port().3410	 */3411	ret = serial_core_port_device_add(ctrl_dev, port);3412	if (ret)3413		goto err_unregister_ctrl_dev;3414 3415	ret = serial_base_match_and_update_preferred_console(drv, port);3416	if (ret)3417		goto err_unregister_port_dev;3418 3419	ret = serial_core_add_one_port(drv, port);3420	if (ret)3421		goto err_unregister_port_dev;3422 3423	mutex_unlock(&port_mutex);3424 3425	return 0;3426 3427err_unregister_port_dev:3428	serial_base_port_device_remove(port->port_dev);3429 3430err_unregister_ctrl_dev:3431	serial_base_ctrl_device_remove(new_ctrl_dev);3432 3433err_unlock:3434	mutex_unlock(&port_mutex);3435 3436	return ret;3437}3438 3439/*3440 * Removes a serial core port device, and the related serial core controller3441 * device if the last instance.3442 */3443void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)3444{3445	struct device *phys_dev = port->dev;3446	struct serial_port_device *port_dev = port->port_dev;3447	struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);3448	int ctrl_id = port->ctrl_id;3449 3450	mutex_lock(&port_mutex);3451 3452	port->flags |= UPF_DEAD;3453 3454	serial_core_remove_one_port(drv, port);3455 3456	/* Note that struct uart_port *port is no longer valid at this point */3457	serial_base_port_device_remove(port_dev);3458 3459	/* Drop the serial core controller device if no ports are using it */3460	if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))3461		serial_base_ctrl_device_remove(ctrl_dev);3462 3463	mutex_unlock(&port_mutex);3464}3465 3466/**3467 * uart_handle_dcd_change - handle a change of carrier detect state3468 * @uport: uart_port structure for the open port3469 * @active: new carrier detect status3470 *3471 * Caller must hold uport->lock.3472 */3473void uart_handle_dcd_change(struct uart_port *uport, bool active)3474{3475	struct tty_port *port = &uport->state->port;3476	struct tty_struct *tty = port->tty;3477	struct tty_ldisc *ld;3478 3479	lockdep_assert_held_once(&uport->lock);3480 3481	if (tty) {3482		ld = tty_ldisc_ref(tty);3483		if (ld) {3484			if (ld->ops->dcd_change)3485				ld->ops->dcd_change(tty, active);3486			tty_ldisc_deref(ld);3487		}3488	}3489 3490	uport->icount.dcd++;3491 3492	if (uart_dcd_enabled(uport)) {3493		if (active)3494			wake_up_interruptible(&port->open_wait);3495		else if (tty)3496			tty_hangup(tty);3497	}3498}3499EXPORT_SYMBOL_GPL(uart_handle_dcd_change);3500 3501/**3502 * uart_handle_cts_change - handle a change of clear-to-send state3503 * @uport: uart_port structure for the open port3504 * @active: new clear-to-send status3505 *3506 * Caller must hold uport->lock.3507 */3508void uart_handle_cts_change(struct uart_port *uport, bool active)3509{3510	lockdep_assert_held_once(&uport->lock);3511 3512	uport->icount.cts++;3513 3514	if (uart_softcts_mode(uport)) {3515		if (uport->hw_stopped) {3516			if (active) {3517				uport->hw_stopped = false;3518				uport->ops->start_tx(uport);3519				uart_write_wakeup(uport);3520			}3521		} else {3522			if (!active) {3523				uport->hw_stopped = true;3524				uport->ops->stop_tx(uport);3525			}3526		}3527 3528	}3529}3530EXPORT_SYMBOL_GPL(uart_handle_cts_change);3531 3532/**3533 * uart_insert_char - push a char to the uart layer3534 *3535 * User is responsible to call tty_flip_buffer_push when they are done with3536 * insertion.3537 *3538 * @port: corresponding port3539 * @status: state of the serial port RX buffer (LSR for 8250)3540 * @overrun: mask of overrun bits in @status3541 * @ch: character to push3542 * @flag: flag for the character (see TTY_NORMAL and friends)3543 */3544void uart_insert_char(struct uart_port *port, unsigned int status,3545		      unsigned int overrun, u8 ch, u8 flag)3546{3547	struct tty_port *tport = &port->state->port;3548 3549	if ((status & port->ignore_status_mask & ~overrun) == 0)3550		if (tty_insert_flip_char(tport, ch, flag) == 0)3551			++port->icount.buf_overrun;3552 3553	/*3554	 * Overrun is special.  Since it's reported immediately,3555	 * it doesn't affect the current character.3556	 */3557	if (status & ~port->ignore_status_mask & overrun)3558		if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)3559			++port->icount.buf_overrun;3560}3561EXPORT_SYMBOL_GPL(uart_insert_char);3562 3563#ifdef CONFIG_MAGIC_SYSRQ_SERIAL3564static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;3565 3566static void uart_sysrq_on(struct work_struct *w)3567{3568	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);3569 3570	sysrq_toggle_support(1);3571	pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",3572		sysrq_toggle_seq_len, sysrq_toggle_seq);3573}3574static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);3575 3576/**3577 * uart_try_toggle_sysrq - Enables SysRq from serial line3578 * @port: uart_port structure where char(s) after BREAK met3579 * @ch: new character in the sequence after received BREAK3580 *3581 * Enables magic SysRq when the required sequence is met on port3582 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).3583 *3584 * Returns: %false if @ch is out of enabling sequence and should be3585 * handled some other way, %true if @ch was consumed.3586 */3587bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)3588{3589	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);3590 3591	if (!sysrq_toggle_seq_len)3592		return false;3593 3594	BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);3595	if (sysrq_toggle_seq[port->sysrq_seq] != ch) {3596		port->sysrq_seq = 0;3597		return false;3598	}3599 3600	if (++port->sysrq_seq < sysrq_toggle_seq_len) {3601		port->sysrq = jiffies + SYSRQ_TIMEOUT;3602		return true;3603	}3604 3605	schedule_work(&sysrq_enable_work);3606 3607	port->sysrq = 0;3608	return true;3609}3610EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);3611#endif3612 3613/**3614 * uart_get_rs485_mode() - retrieve rs485 properties for given uart3615 * @port: uart device's target port3616 *3617 * This function implements the device tree binding described in3618 * Documentation/devicetree/bindings/serial/rs485.txt.3619 */3620int uart_get_rs485_mode(struct uart_port *port)3621{3622	struct serial_rs485 *rs485conf = &port->rs485;3623	struct device *dev = port->dev;3624	enum gpiod_flags dflags;3625	struct gpio_desc *desc;3626	u32 rs485_delay[2];3627	int ret;3628 3629	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))3630		return 0;3631 3632	ret = device_property_read_u32_array(dev, "rs485-rts-delay",3633					     rs485_delay, 2);3634	if (!ret) {3635		rs485conf->delay_rts_before_send = rs485_delay[0];3636		rs485conf->delay_rts_after_send = rs485_delay[1];3637	} else {3638		rs485conf->delay_rts_before_send = 0;3639		rs485conf->delay_rts_after_send = 0;3640	}3641 3642	uart_sanitize_serial_rs485_delays(port, rs485conf);3643 3644	/*3645	 * Clear full-duplex and enabled flags, set RTS polarity to active high3646	 * to get to a defined state with the following properties:3647	 */3648	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |3649			      SER_RS485_TERMINATE_BUS |3650			      SER_RS485_RTS_AFTER_SEND);3651	rs485conf->flags |= SER_RS485_RTS_ON_SEND;3652 3653	if (device_property_read_bool(dev, "rs485-rx-during-tx"))3654		rs485conf->flags |= SER_RS485_RX_DURING_TX;3655 3656	if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))3657		rs485conf->flags |= SER_RS485_ENABLED;3658 3659	if (device_property_read_bool(dev, "rs485-rts-active-low")) {3660		rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;3661		rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;3662	}3663 3664	/*3665	 * Disabling termination by default is the safe choice:  Else if many3666	 * bus participants enable it, no communication is possible at all.3667	 * Works fine for short cables and users may enable for longer cables.3668	 */3669	desc = devm_gpiod_get_optional(dev, "rs485-term", GPIOD_OUT_LOW);3670	if (IS_ERR(desc))3671		return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-term-gpios\n");3672	port->rs485_term_gpio = desc;3673	if (port->rs485_term_gpio)3674		port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;3675 3676	dflags = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?3677		 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;3678	desc = devm_gpiod_get_optional(dev, "rs485-rx-during-tx", dflags);3679	if (IS_ERR(desc))3680		return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");3681	port->rs485_rx_during_tx_gpio = desc;3682	if (port->rs485_rx_during_tx_gpio)3683		port->rs485_supported.flags |= SER_RS485_RX_DURING_TX;3684 3685	return 0;3686}3687EXPORT_SYMBOL_GPL(uart_get_rs485_mode);3688 3689/* Compile-time assertions for serial_rs485 layout */3690static_assert(offsetof(struct serial_rs485, padding) ==3691              (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));3692static_assert(offsetof(struct serial_rs485, padding1) ==3693	      offsetof(struct serial_rs485, padding[1]));3694static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==3695	      sizeof(struct serial_rs485));3696 3697MODULE_DESCRIPTION("Serial driver core");3698MODULE_LICENSE("GPL");3699