serial_core.h

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 *  linux/drivers/char/serial_core.h
   4 *
   5 *  Copyright (C) 2000 Deep Blue Solutions Ltd.
   6 */
   7#ifndef LINUX_SERIAL_CORE_H
   8#define LINUX_SERIAL_CORE_H
   9
  10#include <linux/bitops.h>
  11#include <linux/compiler.h>
  12#include <linux/console.h>
  13#include <linux/interrupt.h>
  14#include <linux/lockdep.h>
  15#include <linux/printk.h>
  16#include <linux/spinlock.h>
  17#include <linux/sched.h>
  18#include <linux/tty.h>
  19#include <linux/mutex.h>
  20#include <linux/sysrq.h>
  21#include <uapi/linux/serial_core.h>
  22
  23#ifdef CONFIG_SERIAL_CORE_CONSOLE
  24#define uart_console(port) \
  25	((port)->cons && (port)->cons->index == (port)->line)
  26#else
  27#define uart_console(port)      ({ (void)port; 0; })
  28#endif
  29
  30struct uart_port;
  31struct serial_struct;
  32struct serial_port_device;
  33struct device;
  34struct gpio_desc;
  35
  36/**
  37 * struct uart_ops -- interface between serial_core and the driver
  38 *
  39 * This structure describes all the operations that can be done on the
  40 * physical hardware.
  41 *
  42 * @tx_empty: ``unsigned int ()(struct uart_port *port)``
  43 *
  44 *	This function tests whether the transmitter fifo and shifter for the
  45 *	@port is empty. If it is empty, this function should return
  46 *	%TIOCSER_TEMT, otherwise return 0. If the port does not support this
  47 *	operation, then it should return %TIOCSER_TEMT.
  48 *
  49 *	Locking: none.
  50 *	Interrupts: caller dependent.
  51 *	This call must not sleep
  52 *
  53 * @set_mctrl: ``void ()(struct uart_port *port, unsigned int mctrl)``
  54 *
  55 *	This function sets the modem control lines for @port to the state
  56 *	described by @mctrl. The relevant bits of @mctrl are:
  57 *
  58 *		- %TIOCM_RTS	RTS signal.
  59 *		- %TIOCM_DTR	DTR signal.
  60 *		- %TIOCM_OUT1	OUT1 signal.
  61 *		- %TIOCM_OUT2	OUT2 signal.
  62 *		- %TIOCM_LOOP	Set the port into loopback mode.
  63 *
  64 *	If the appropriate bit is set, the signal should be driven
  65 *	active.  If the bit is clear, the signal should be driven
  66 *	inactive.
  67 *
  68 *	Locking: @port->lock taken.
  69 *	Interrupts: locally disabled.
  70 *	This call must not sleep
  71 *
  72 * @get_mctrl: ``unsigned int ()(struct uart_port *port)``
  73 *
  74 *	Returns the current state of modem control inputs of @port. The state
  75 *	of the outputs should not be returned, since the core keeps track of
  76 *	their state. The state information should include:
  77 *
  78 *		- %TIOCM_CAR	state of DCD signal
  79 *		- %TIOCM_CTS	state of CTS signal
  80 *		- %TIOCM_DSR	state of DSR signal
  81 *		- %TIOCM_RI	state of RI signal
  82 *
  83 *	The bit is set if the signal is currently driven active.  If
  84 *	the port does not support CTS, DCD or DSR, the driver should
  85 *	indicate that the signal is permanently active. If RI is
  86 *	not available, the signal should not be indicated as active.
  87 *
  88 *	Locking: @port->lock taken.
  89 *	Interrupts: locally disabled.
  90 *	This call must not sleep
  91 *
  92 * @stop_tx: ``void ()(struct uart_port *port)``
  93 *
  94 *	Stop transmitting characters. This might be due to the CTS line
  95 *	becoming inactive or the tty layer indicating we want to stop
  96 *	transmission due to an %XOFF character.
  97 *
  98 *	The driver should stop transmitting characters as soon as possible.
  99 *
 100 *	Locking: @port->lock taken.
 101 *	Interrupts: locally disabled.
 102 *	This call must not sleep
 103 *
 104 * @start_tx: ``void ()(struct uart_port *port)``
 105 *
 106 *	Start transmitting characters.
 107 *
 108 *	Locking: @port->lock taken.
 109 *	Interrupts: locally disabled.
 110 *	This call must not sleep
 111 *
 112 * @throttle: ``void ()(struct uart_port *port)``
 113 *
 114 *	Notify the serial driver that input buffers for the line discipline are
 115 *	close to full, and it should somehow signal that no more characters
 116 *	should be sent to the serial port.
 117 *	This will be called only if hardware assisted flow control is enabled.
 118 *
 119 *	Locking: serialized with @unthrottle() and termios modification by the
 120 *	tty layer.
 121 *
 122 * @unthrottle: ``void ()(struct uart_port *port)``
 123 *
 124 *	Notify the serial driver that characters can now be sent to the serial
 125 *	port without fear of overrunning the input buffers of the line
 126 *	disciplines.
 127 *
 128 *	This will be called only if hardware assisted flow control is enabled.
 129 *
 130 *	Locking: serialized with @throttle() and termios modification by the
 131 *	tty layer.
 132 *
 133 * @send_xchar: ``void ()(struct uart_port *port, char ch)``
 134 *
 135 *	Transmit a high priority character, even if the port is stopped. This
 136 *	is used to implement XON/XOFF flow control and tcflow(). If the serial
 137 *	driver does not implement this function, the tty core will append the
 138 *	character to the circular buffer and then call start_tx() / stop_tx()
 139 *	to flush the data out.
 140 *
 141 *	Do not transmit if @ch == '\0' (%__DISABLED_CHAR).
 142 *
 143 *	Locking: none.
 144 *	Interrupts: caller dependent.
 145 *
 146 * @start_rx: ``void ()(struct uart_port *port)``
 147 *
 148 *	Start receiving characters.
 149 *
 150 *	Locking: @port->lock taken.
 151 *	Interrupts: locally disabled.
 152 *	This call must not sleep
 153 *
 154 * @stop_rx: ``void ()(struct uart_port *port)``
 155 *
 156 *	Stop receiving characters; the @port is in the process of being closed.
 157 *
 158 *	Locking: @port->lock taken.
 159 *	Interrupts: locally disabled.
 160 *	This call must not sleep
 161 *
 162 * @enable_ms: ``void ()(struct uart_port *port)``
 163 *
 164 *	Enable the modem status interrupts.
 165 *
 166 *	This method may be called multiple times. Modem status interrupts
 167 *	should be disabled when the @shutdown() method is called.
 168 *
 169 *	Locking: @port->lock taken.
 170 *	Interrupts: locally disabled.
 171 *	This call must not sleep
 172 *
 173 * @break_ctl: ``void ()(struct uart_port *port, int ctl)``
 174 *
 175 *	Control the transmission of a break signal. If @ctl is nonzero, the
 176 *	break signal should be transmitted. The signal should be terminated
 177 *	when another call is made with a zero @ctl.
 178 *
 179 *	Locking: caller holds tty_port->mutex
 180 *
 181 * @startup: ``int ()(struct uart_port *port)``
 182 *
 183 *	Grab any interrupt resources and initialise any low level driver state.
 184 *	Enable the port for reception. It should not activate RTS nor DTR;
 185 *	this will be done via a separate call to @set_mctrl().
 186 *
 187 *	This method will only be called when the port is initially opened.
 188 *
 189 *	Locking: port_sem taken.
 190 *	Interrupts: globally disabled.
 191 *
 192 * @shutdown: ``void ()(struct uart_port *port)``
 193 *
 194 *	Disable the @port, disable any break condition that may be in effect,
 195 *	and free any interrupt resources. It should not disable RTS nor DTR;
 196 *	this will have already been done via a separate call to @set_mctrl().
 197 *
 198 *	Drivers must not access @port->state once this call has completed.
 199 *
 200 *	This method will only be called when there are no more users of this
 201 *	@port.
 202 *
 203 *	Locking: port_sem taken.
 204 *	Interrupts: caller dependent.
 205 *
 206 * @flush_buffer: ``void ()(struct uart_port *port)``
 207 *
 208 *	Flush any write buffers, reset any DMA state and stop any ongoing DMA
 209 *	transfers.
 210 *
 211 *	This will be called whenever the @port->state->xmit circular buffer is
 212 *	cleared.
 213 *
 214 *	Locking: @port->lock taken.
 215 *	Interrupts: locally disabled.
 216 *	This call must not sleep
 217 *
 218 * @set_termios: ``void ()(struct uart_port *port, struct ktermios *new,
 219 *			struct ktermios *old)``
 220 *
 221 *	Change the @port parameters, including word length, parity, stop bits.
 222 *	Update @port->read_status_mask and @port->ignore_status_mask to
 223 *	indicate the types of events we are interested in receiving. Relevant
 224 *	ktermios::c_cflag bits are:
 225 *
 226 *	- %CSIZE - word size
 227 *	- %CSTOPB - 2 stop bits
 228 *	- %PARENB - parity enable
 229 *	- %PARODD - odd parity (when %PARENB is in force)
 230 *	- %ADDRB - address bit (changed through uart_port::rs485_config()).
 231 *	- %CREAD - enable reception of characters (if not set, still receive
 232 *	  characters from the port, but throw them away).
 233 *	- %CRTSCTS - if set, enable CTS status change reporting.
 234 *	- %CLOCAL - if not set, enable modem status change reporting.
 235 *
 236 *	Relevant ktermios::c_iflag bits are:
 237 *
 238 *	- %INPCK - enable frame and parity error events to be passed to the TTY
 239 *	  layer.
 240 *	- %BRKINT / %PARMRK - both of these enable break events to be passed to
 241 *	  the TTY layer.
 242 *	- %IGNPAR - ignore parity and framing errors.
 243 *	- %IGNBRK - ignore break errors. If %IGNPAR is also set, ignore overrun
 244 *	  errors as well.
 245 *
 246 *	The interaction of the ktermios::c_iflag bits is as follows (parity
 247 *	error given as an example):
 248 *
 249 *	============ ======= ======= =========================================
 250 *	Parity error INPCK   IGNPAR
 251 *	============ ======= ======= =========================================
 252 *	n/a	     0	     n/a     character received, marked as %TTY_NORMAL
 253 *	None	     1	     n/a     character received, marked as %TTY_NORMAL
 254 *	Yes	     1	     0	     character received, marked as %TTY_PARITY
 255 *	Yes	     1	     1	     character discarded
 256 *	============ ======= ======= =========================================
 257 *
 258 *	Other flags may be used (eg, xon/xoff characters) if your hardware
 259 *	supports hardware "soft" flow control.
 260 *
 261 *	Locking: caller holds tty_port->mutex
 262 *	Interrupts: caller dependent.
 263 *	This call must not sleep
 264 *
 265 * @set_ldisc: ``void ()(struct uart_port *port, struct ktermios *termios)``
 266 *
 267 *	Notifier for discipline change. See
 268 *	Documentation/driver-api/tty/tty_ldisc.rst.
 269 *
 270 *	Locking: caller holds tty_port->mutex
 271 *
 272 * @pm: ``void ()(struct uart_port *port, unsigned int state,
 273 *		 unsigned int oldstate)``
 274 *
 275 *	Perform any power management related activities on the specified @port.
 276 *	@state indicates the new state (defined by enum uart_pm_state),
 277 *	@oldstate indicates the previous state.
 278 *
 279 *	This function should not be used to grab any resources.
 280 *
 281 *	This will be called when the @port is initially opened and finally
 282 *	closed, except when the @port is also the system console. This will
 283 *	occur even if %CONFIG_PM is not set.
 284 *
 285 *	Locking: none.
 286 *	Interrupts: caller dependent.
 287 *
 288 * @type: ``const char *()(struct uart_port *port)``
 289 *
 290 *	Return a pointer to a string constant describing the specified @port,
 291 *	or return %NULL, in which case the string 'unknown' is substituted.
 292 *
 293 *	Locking: none.
 294 *	Interrupts: caller dependent.
 295 *
 296 * @release_port: ``void ()(struct uart_port *port)``
 297 *
 298 *	Release any memory and IO region resources currently in use by the
 299 *	@port.
 300 *
 301 *	Locking: none.
 302 *	Interrupts: caller dependent.
 303 *
 304 * @request_port: ``int ()(struct uart_port *port)``
 305 *
 306 *	Request any memory and IO region resources required by the port. If any
 307 *	fail, no resources should be registered when this function returns, and
 308 *	it should return -%EBUSY on failure.
 309 *
 310 *	Locking: none.
 311 *	Interrupts: caller dependent.
 312 *
 313 * @config_port: ``void ()(struct uart_port *port, int type)``
 314 *
 315 *	Perform any autoconfiguration steps required for the @port. @type
 316 *	contains a bit mask of the required configuration. %UART_CONFIG_TYPE
 317 *	indicates that the port requires detection and identification.
 318 *	@port->type should be set to the type found, or %PORT_UNKNOWN if no
 319 *	port was detected.
 320 *
 321 *	%UART_CONFIG_IRQ indicates autoconfiguration of the interrupt signal,
 322 *	which should be probed using standard kernel autoprobing techniques.
 323 *	This is not necessary on platforms where ports have interrupts
 324 *	internally hard wired (eg, system on a chip implementations).
 325 *
 326 *	Locking: none.
 327 *	Interrupts: caller dependent.
 328 *
 329 * @verify_port: ``int ()(struct uart_port *port,
 330 *			struct serial_struct *serinfo)``
 331 *
 332 *	Verify the new serial port information contained within @serinfo is
 333 *	suitable for this port type.
 334 *
 335 *	Locking: none.
 336 *	Interrupts: caller dependent.
 337 *
 338 * @ioctl: ``int ()(struct uart_port *port, unsigned int cmd,
 339 *		unsigned long arg)``
 340 *
 341 *	Perform any port specific IOCTLs. IOCTL commands must be defined using
 342 *	the standard numbering system found in <asm/ioctl.h>.
 343 *
 344 *	Locking: none.
 345 *	Interrupts: caller dependent.
 346 *
 347 * @poll_init: ``int ()(struct uart_port *port)``
 348 *
 349 *	Called by kgdb to perform the minimal hardware initialization needed to
 350 *	support @poll_put_char() and @poll_get_char(). Unlike @startup(), this
 351 *	should not request interrupts.
 352 *
 353 *	Locking: %tty_mutex and tty_port->mutex taken.
 354 *	Interrupts: n/a.
 355 *
 356 * @poll_put_char: ``void ()(struct uart_port *port, unsigned char ch)``
 357 *
 358 *	Called by kgdb to write a single character @ch directly to the serial
 359 *	@port. It can and should block until there is space in the TX FIFO.
 360 *
 361 *	Locking: none.
 362 *	Interrupts: caller dependent.
 363 *	This call must not sleep
 364 *
 365 * @poll_get_char: ``int ()(struct uart_port *port)``
 366 *
 367 *	Called by kgdb to read a single character directly from the serial
 368 *	port. If data is available, it should be returned; otherwise the
 369 *	function should return %NO_POLL_CHAR immediately.
 370 *
 371 *	Locking: none.
 372 *	Interrupts: caller dependent.
 373 *	This call must not sleep
 374 */
 375struct uart_ops {
 376	unsigned int	(*tx_empty)(struct uart_port *);
 377	void		(*set_mctrl)(struct uart_port *, unsigned int mctrl);
 378	unsigned int	(*get_mctrl)(struct uart_port *);
 379	void		(*stop_tx)(struct uart_port *);
 380	void		(*start_tx)(struct uart_port *);
 381	void		(*throttle)(struct uart_port *);
 382	void		(*unthrottle)(struct uart_port *);
 383	void		(*send_xchar)(struct uart_port *, char ch);
 384	void		(*stop_rx)(struct uart_port *);
 385	void		(*start_rx)(struct uart_port *);
 386	void		(*enable_ms)(struct uart_port *);
 387	void		(*break_ctl)(struct uart_port *, int ctl);
 388	int		(*startup)(struct uart_port *);
 389	void		(*shutdown)(struct uart_port *);
 390	void		(*flush_buffer)(struct uart_port *);
 391	void		(*set_termios)(struct uart_port *, struct ktermios *new,
 392				       const struct ktermios *old);
 393	void		(*set_ldisc)(struct uart_port *, struct ktermios *);
 394	void		(*pm)(struct uart_port *, unsigned int state,
 395			      unsigned int oldstate);
 396	const char	*(*type)(struct uart_port *);
 397	void		(*release_port)(struct uart_port *);
 398	int		(*request_port)(struct uart_port *);
 399	void		(*config_port)(struct uart_port *, int);
 400	int		(*verify_port)(struct uart_port *, struct serial_struct *);
 401	int		(*ioctl)(struct uart_port *, unsigned int, unsigned long);
 402#ifdef CONFIG_CONSOLE_POLL
 403	int		(*poll_init)(struct uart_port *);
 404	void		(*poll_put_char)(struct uart_port *, unsigned char);
 405	int		(*poll_get_char)(struct uart_port *);
 406#endif
 407};
 408
 409#define NO_POLL_CHAR		0x00ff0000
 410#define UART_CONFIG_TYPE	(1 << 0)
 411#define UART_CONFIG_IRQ		(1 << 1)
 412
 413struct uart_icount {
 414	__u32	cts;
 415	__u32	dsr;
 416	__u32	rng;
 417	__u32	dcd;
 418	__u32	rx;
 419	__u32	tx;
 420	__u32	frame;
 421	__u32	overrun;
 422	__u32	parity;
 423	__u32	brk;
 424	__u32	buf_overrun;
 425};
 426
 427typedef u64 __bitwise upf_t;
 428typedef unsigned int __bitwise upstat_t;
 429
 430enum uart_iotype {
 431	UPIO_UNKNOWN	= -1,
 432	UPIO_PORT	= SERIAL_IO_PORT,	/* 8b I/O port access */
 433	UPIO_HUB6	= SERIAL_IO_HUB6,	/* Hub6 ISA card */
 434	UPIO_MEM	= SERIAL_IO_MEM,	/* driver-specific */
 435	UPIO_MEM32	= SERIAL_IO_MEM32,	/* 32b little endian */
 436	UPIO_AU		= SERIAL_IO_AU,		/* Au1x00 and RT288x type IO */
 437	UPIO_TSI	= SERIAL_IO_TSI,	/* Tsi108/109 type IO */
 438	UPIO_MEM32BE	= SERIAL_IO_MEM32BE,	/* 32b big endian */
 439	UPIO_MEM16	= SERIAL_IO_MEM16,	/* 16b little endian */
 440};
 441
 442struct uart_port {
 443	spinlock_t		lock;			/* port lock */
 444	unsigned long		iobase;			/* in/out[bwl] */
 445	unsigned char __iomem	*membase;		/* read/write[bwl] */
 446	u32			(*serial_in)(struct uart_port *, unsigned int offset);
 447	void			(*serial_out)(struct uart_port *, unsigned int offset, u32 val);
 448	void			(*set_termios)(struct uart_port *,
 449				               struct ktermios *new,
 450				               const struct ktermios *old);
 451	void			(*set_ldisc)(struct uart_port *,
 452					     struct ktermios *);
 453	unsigned int		(*get_mctrl)(struct uart_port *);
 454	void			(*set_mctrl)(struct uart_port *, unsigned int);
 455	unsigned int		(*get_divisor)(struct uart_port *,
 456					       unsigned int baud,
 457					       unsigned int *frac);
 458	void			(*set_divisor)(struct uart_port *,
 459					       unsigned int baud,
 460					       unsigned int quot,
 461					       unsigned int quot_frac);
 462	int			(*startup)(struct uart_port *port);
 463	void			(*shutdown)(struct uart_port *port);
 464	void			(*throttle)(struct uart_port *port);
 465	void			(*unthrottle)(struct uart_port *port);
 466	int			(*handle_irq)(struct uart_port *);
 467	void			(*pm)(struct uart_port *, unsigned int state,
 468				      unsigned int old);
 469	void			(*handle_break)(struct uart_port *);
 470	int			(*rs485_config)(struct uart_port *,
 471						struct ktermios *termios,
 472						struct serial_rs485 *rs485);
 473	int			(*iso7816_config)(struct uart_port *,
 474						  struct serial_iso7816 *iso7816);
 475	unsigned int		ctrl_id;		/* optional serial core controller id */
 476	unsigned int		port_id;		/* optional serial core port id */
 477	unsigned int		irq;			/* irq number */
 478	unsigned long		irqflags;		/* irq flags  */
 479	unsigned int		uartclk;		/* base uart clock */
 480	unsigned int		fifosize;		/* tx fifo size */
 481	unsigned char		x_char;			/* xon/xoff char */
 482	unsigned char		regshift;		/* reg offset shift */
 483
 484	unsigned char		quirks;			/* internal quirks */
 485
 486	/* internal quirks must be updated while holding port mutex */
 487#define UPQ_NO_TXEN_TEST	BIT(0)
 488
 489	enum uart_iotype	iotype;			/* io access style */
 490
 491	unsigned int		read_status_mask;	/* driver specific */
 492	unsigned int		ignore_status_mask;	/* driver specific */
 493	struct uart_state	*state;			/* pointer to parent state */
 494	struct uart_icount	icount;			/* statistics */
 495
 496	struct console		*cons;			/* struct console, if any */
 497	/* flags must be updated while holding port mutex */
 498	upf_t			flags;
 499
 500	/*
 501	 * These flags must be equivalent to the flags defined in
 502	 * include/uapi/linux/tty_flags.h which are the userspace definitions
 503	 * assigned from the serial_struct flags in uart_set_info()
 504	 * [for bit definitions in the UPF_CHANGE_MASK]
 505	 *
 506	 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable
 507	 * The remaining bits are serial-core specific and not modifiable by
 508	 * userspace.
 509	 */
 510#ifdef CONFIG_HAS_IOPORT
 511#define UPF_FOURPORT		((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
 512#else
 513#define UPF_FOURPORT		0
 514#endif
 515#define UPF_SAK			((__force upf_t) ASYNC_SAK            /* 2  */ )
 516#define UPF_SPD_HI		((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
 517#define UPF_SPD_VHI		((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
 518#define UPF_SPD_CUST		((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
 519#define UPF_SPD_WARP		((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
 520#define UPF_SPD_MASK		((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
 521#define UPF_SKIP_TEST		((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
 522#define UPF_AUTO_IRQ		((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
 523#define UPF_HARDPPS_CD		((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
 524#define UPF_SPD_SHI		((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
 525#define UPF_LOW_LATENCY		((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
 526#define UPF_BUGGY_UART		((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
 527#define UPF_MAGIC_MULTIPLIER	((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
 528
 529#define UPF_NO_THRE_TEST	((__force upf_t) BIT_ULL(19))
 530/* Port has hardware-assisted h/w flow control */
 531#define UPF_AUTO_CTS		((__force upf_t) BIT_ULL(20))
 532#define UPF_AUTO_RTS		((__force upf_t) BIT_ULL(21))
 533#define UPF_HARD_FLOW		((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
 534/* Port has hardware-assisted s/w flow control */
 535#define UPF_SOFT_FLOW		((__force upf_t) BIT_ULL(22))
 536#define UPF_CONS_FLOW		((__force upf_t) BIT_ULL(23))
 537#define UPF_SHARE_IRQ		((__force upf_t) BIT_ULL(24))
 538#define UPF_EXAR_EFR		((__force upf_t) BIT_ULL(25))
 539#define UPF_BUG_THRE		((__force upf_t) BIT_ULL(26))
 540/* The exact UART type is known and should not be probed.  */
 541#define UPF_FIXED_TYPE		((__force upf_t) BIT_ULL(27))
 542#define UPF_BOOT_AUTOCONF	((__force upf_t) BIT_ULL(28))
 543#define UPF_FIXED_PORT		((__force upf_t) BIT_ULL(29))
 544#define UPF_DEAD		((__force upf_t) BIT_ULL(30))
 545#define UPF_IOREMAP		((__force upf_t) BIT_ULL(31))
 546#define UPF_FULL_PROBE		((__force upf_t) BIT_ULL(32))
 547
 548#define __UPF_CHANGE_MASK	0x17fff
 549#define UPF_CHANGE_MASK		((__force upf_t) __UPF_CHANGE_MASK)
 550#define UPF_USR_MASK		((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
 551
 552#if __UPF_CHANGE_MASK > ASYNC_FLAGS
 553#error Change mask not equivalent to userspace-visible bit defines
 554#endif
 555
 556	/*
 557	 * Must hold termios_rwsem, port mutex and port lock to change;
 558	 * can hold any one lock to read.
 559	 */
 560	upstat_t		status;
 561
 562#define UPSTAT_CTS_ENABLE	((__force upstat_t) (1 << 0))
 563#define UPSTAT_DCD_ENABLE	((__force upstat_t) (1 << 1))
 564#define UPSTAT_AUTORTS		((__force upstat_t) (1 << 2))
 565#define UPSTAT_AUTOCTS		((__force upstat_t) (1 << 3))
 566#define UPSTAT_AUTOXOFF		((__force upstat_t) (1 << 4))
 567#define UPSTAT_SYNC_FIFO	((__force upstat_t) (1 << 5))
 568
 569	bool			hw_stopped;		/* sw-assisted CTS flow state */
 570	unsigned int		mctrl;			/* current modem ctrl settings */
 571	unsigned int		frame_time;		/* frame timing in ns */
 572	unsigned int		type;			/* port type */
 573	const struct uart_ops	*ops;
 574	unsigned int		custom_divisor;
 575	unsigned int		line;			/* port index */
 576	unsigned int		minor;
 577	resource_size_t		mapbase;		/* for ioremap */
 578	resource_size_t		mapsize;
 579	struct device		*dev;			/* serial port physical parent device */
 580	struct serial_port_device *port_dev;		/* serial core port device */
 581
 582	unsigned long		sysrq;			/* sysrq timeout */
 583	u8			sysrq_ch;		/* char for sysrq */
 584	unsigned char		has_sysrq;
 585	unsigned char		sysrq_seq;		/* index in sysrq_toggle_seq */
 586
 587	unsigned char		hub6;			/* this should be in the 8250 driver */
 588	unsigned char		suspended;
 589	unsigned char		console_reinit;
 590	const char		*name;			/* port name */
 591	struct attribute_group	*attr_group;		/* port specific attributes */
 592	const struct attribute_group **tty_groups;	/* all attributes (serial core use only) */
 593	struct serial_rs485     rs485;
 594	struct serial_rs485	rs485_supported;	/* Supported mask for serial_rs485 */
 595	struct gpio_desc	*rs485_term_gpio;	/* enable RS485 bus termination */
 596	struct gpio_desc	*rs485_rx_during_tx_gpio; /* Output GPIO that sets the state of RS485 RX during TX */
 597	struct serial_iso7816   iso7816;
 598	void			*private_data;		/* generic platform data pointer */
 599};
 600
 601/*
 602 * Only for console->device_lock()/_unlock() callbacks and internal
 603 * port lock wrapper synchronization.
 604 */
 605static inline void __uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags)
 606{
 607	spin_lock_irqsave(&up->lock, *flags);
 608}
 609
 610/*
 611 * Only for console->device_lock()/_unlock() callbacks and internal
 612 * port lock wrapper synchronization.
 613 */
 614static inline void __uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags)
 615{
 616	spin_unlock_irqrestore(&up->lock, flags);
 617}
 618
 619/**
 620 * uart_port_set_cons - Safely set the @cons field for a uart
 621 * @up:		The uart port to set
 622 * @con:	The new console to set to
 623 *
 624 * This function must be used to set @up->cons. It uses the port lock to
 625 * synchronize with the port lock wrappers in order to ensure that the console
 626 * cannot change or disappear while another context is holding the port lock.
 627 */
 628static inline void uart_port_set_cons(struct uart_port *up, struct console *con)
 629{
 630	unsigned long flags;
 631
 632	__uart_port_lock_irqsave(up, &flags);
 633	up->cons = con;
 634	__uart_port_unlock_irqrestore(up, flags);
 635}
 636
 637/* Only for internal port lock wrapper usage. */
 638static inline bool __uart_port_using_nbcon(struct uart_port *up)
 639{
 640	lockdep_assert_held_once(&up->lock);
 641
 642	if (likely(!uart_console(up)))
 643		return false;
 644
 645	/*
 646	 * @up->cons is only modified under the port lock. Therefore it is
 647	 * certain that it cannot disappear here.
 648	 *
 649	 * @up->cons->node is added/removed from the console list under the
 650	 * port lock. Therefore it is certain that the registration status
 651	 * cannot change here, thus @up->cons->flags can be read directly.
 652	 */
 653	if (hlist_unhashed_lockless(&up->cons->node) ||
 654	    !(up->cons->flags & CON_NBCON) ||
 655	    !up->cons->write_atomic) {
 656		return false;
 657	}
 658
 659	return true;
 660}
 661
 662/* Only for internal port lock wrapper usage. */
 663static inline bool __uart_port_nbcon_try_acquire(struct uart_port *up)
 664{
 665	if (!__uart_port_using_nbcon(up))
 666		return true;
 667
 668	return nbcon_device_try_acquire(up->cons);
 669}
 670
 671/* Only for internal port lock wrapper usage. */
 672static inline void __uart_port_nbcon_acquire(struct uart_port *up)
 673{
 674	if (!__uart_port_using_nbcon(up))
 675		return;
 676
 677	while (!nbcon_device_try_acquire(up->cons))
 678		cpu_relax();
 679}
 680
 681/* Only for internal port lock wrapper usage. */
 682static inline void __uart_port_nbcon_release(struct uart_port *up)
 683{
 684	if (!__uart_port_using_nbcon(up))
 685		return;
 686
 687	nbcon_device_release(up->cons);
 688}
 689
 690/**
 691 * uart_port_lock - Lock the UART port
 692 * @up:		Pointer to UART port structure
 693 */
 694static inline void uart_port_lock(struct uart_port *up)
 695{
 696	spin_lock(&up->lock);
 697	__uart_port_nbcon_acquire(up);
 698}
 699
 700/**
 701 * uart_port_lock_irq - Lock the UART port and disable interrupts
 702 * @up:		Pointer to UART port structure
 703 */
 704static inline void uart_port_lock_irq(struct uart_port *up)
 705{
 706	spin_lock_irq(&up->lock);
 707	__uart_port_nbcon_acquire(up);
 708}
 709
 710/**
 711 * uart_port_lock_irqsave - Lock the UART port, save and disable interrupts
 712 * @up:		Pointer to UART port structure
 713 * @flags:	Pointer to interrupt flags storage
 714 */
 715static inline void uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags)
 716{
 717	spin_lock_irqsave(&up->lock, *flags);
 718	__uart_port_nbcon_acquire(up);
 719}
 720
 721/**
 722 * uart_port_trylock - Try to lock the UART port
 723 * @up:		Pointer to UART port structure
 724 *
 725 * Returns: True if lock was acquired, false otherwise
 726 */
 727static inline bool uart_port_trylock(struct uart_port *up)
 728{
 729	if (!spin_trylock(&up->lock))
 730		return false;
 731
 732	if (!__uart_port_nbcon_try_acquire(up)) {
 733		spin_unlock(&up->lock);
 734		return false;
 735	}
 736
 737	return true;
 738}
 739
 740/**
 741 * uart_port_trylock_irqsave - Try to lock the UART port, save and disable interrupts
 742 * @up:		Pointer to UART port structure
 743 * @flags:	Pointer to interrupt flags storage
 744 *
 745 * Returns: True if lock was acquired, false otherwise
 746 */
 747static inline bool uart_port_trylock_irqsave(struct uart_port *up, unsigned long *flags)
 748{
 749	if (!spin_trylock_irqsave(&up->lock, *flags))
 750		return false;
 751
 752	if (!__uart_port_nbcon_try_acquire(up)) {
 753		spin_unlock_irqrestore(&up->lock, *flags);
 754		return false;
 755	}
 756
 757	return true;
 758}
 759
 760/**
 761 * uart_port_unlock - Unlock the UART port
 762 * @up:		Pointer to UART port structure
 763 */
 764static inline void uart_port_unlock(struct uart_port *up)
 765{
 766	__uart_port_nbcon_release(up);
 767	spin_unlock(&up->lock);
 768}
 769
 770/**
 771 * uart_port_unlock_irq - Unlock the UART port and re-enable interrupts
 772 * @up:		Pointer to UART port structure
 773 */
 774static inline void uart_port_unlock_irq(struct uart_port *up)
 775{
 776	__uart_port_nbcon_release(up);
 777	spin_unlock_irq(&up->lock);
 778}
 779
 780/**
 781 * uart_port_unlock_irqrestore - Unlock the UART port, restore interrupts
 782 * @up:		Pointer to UART port structure
 783 * @flags:	The saved interrupt flags for restore
 784 */
 785static inline void uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags)
 786{
 787	__uart_port_nbcon_release(up);
 788	spin_unlock_irqrestore(&up->lock, flags);
 789}
 790
 791DEFINE_GUARD(uart_port_lock, struct uart_port *, uart_port_lock(_T), uart_port_unlock(_T));
 792DEFINE_GUARD_COND(uart_port_lock, _try, uart_port_trylock(_T));
 793
 794DEFINE_GUARD(uart_port_lock_irq, struct uart_port *, uart_port_lock_irq(_T),
 795	     uart_port_unlock_irq(_T));
 796
 797DEFINE_LOCK_GUARD_1(uart_port_lock_irqsave, struct uart_port,
 798                    uart_port_lock_irqsave(_T->lock, &_T->flags),
 799                    uart_port_unlock_irqrestore(_T->lock, _T->flags),
 800                    unsigned long flags);
 801DEFINE_LOCK_GUARD_1_COND(uart_port_lock_irqsave, _try,
 802			 uart_port_trylock_irqsave(_T->lock, &_T->flags));
 803
 804static inline int serial_port_in(struct uart_port *up, int offset)
 805{
 806	return up->serial_in(up, offset);
 807}
 808
 809static inline void serial_port_out(struct uart_port *up, int offset, int value)
 810{
 811	up->serial_out(up, offset, value);
 812}
 813
 814/**
 815 * enum uart_pm_state - power states for UARTs
 816 * @UART_PM_STATE_ON: UART is powered, up and operational
 817 * @UART_PM_STATE_OFF: UART is powered off
 818 * @UART_PM_STATE_UNDEFINED: sentinel
 819 */
 820enum uart_pm_state {
 821	UART_PM_STATE_ON = 0,
 822	UART_PM_STATE_OFF = 3, /* number taken from ACPI */
 823	UART_PM_STATE_UNDEFINED,
 824};
 825
 826/*
 827 * This is the state information which is persistent across opens.
 828 */
 829struct uart_state {
 830	struct tty_port		port;
 831
 832	enum uart_pm_state	pm_state;
 833
 834	atomic_t		refcount;
 835	wait_queue_head_t	remove_wait;
 836	struct uart_port	*uart_port;
 837};
 838
 839#define UART_XMIT_SIZE	PAGE_SIZE
 840
 841
 842/* number of characters left in xmit buffer before we ask for more */
 843#define WAKEUP_CHARS		256
 844
 845/**
 846 * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
 847 * @up: uart_port structure describing the port
 848 * @chars: number of characters sent
 849 *
 850 * This function advances the tail of circular xmit buffer by the number of
 851 * @chars transmitted and handles accounting of transmitted bytes (into
 852 * @up's icount.tx).
 853 */
 854static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars)
 855{
 856	struct tty_port *tport = &up->state->port;
 857
 858	kfifo_skip_count(&tport->xmit_fifo, chars);
 859	up->icount.tx += chars;
 860}
 861
 862static inline unsigned int uart_fifo_out(struct uart_port *up,
 863		unsigned char *buf, unsigned int chars)
 864{
 865	struct tty_port *tport = &up->state->port;
 866
 867	chars = kfifo_out(&tport->xmit_fifo, buf, chars);
 868	up->icount.tx += chars;
 869
 870	return chars;
 871}
 872
 873static inline unsigned int uart_fifo_get(struct uart_port *up,
 874		unsigned char *ch)
 875{
 876	struct tty_port *tport = &up->state->port;
 877	unsigned int chars;
 878
 879	chars = kfifo_get(&tport->xmit_fifo, ch);
 880	up->icount.tx += chars;
 881
 882	return chars;
 883}
 884
 885struct module;
 886struct tty_driver;
 887
 888struct uart_driver {
 889	struct module		*owner;
 890	const char		*driver_name;
 891	const char		*dev_name;
 892	int			 major;
 893	int			 minor;
 894	int			 nr;
 895	struct console		*cons;
 896
 897	/*
 898	 * these are private; the low level driver should not
 899	 * touch these; they should be initialised to NULL
 900	 */
 901	struct uart_state	*state;
 902	struct tty_driver	*tty_driver;
 903};
 904
 905void uart_write_wakeup(struct uart_port *port);
 906
 907/**
 908 * enum UART_TX_FLAGS -- flags for uart_port_tx_flags()
 909 *
 910 * @UART_TX_NOSTOP: don't call port->ops->stop_tx() on empty buffer
 911 */
 912enum UART_TX_FLAGS {
 913	UART_TX_NOSTOP = BIT(0),
 914};
 915
 916#define __uart_port_tx(uport, ch, flags, tx_ready, put_char, tx_done,	      \
 917		       for_test, for_post)				      \
 918({									      \
 919	struct uart_port *__port = (uport);				      \
 920	struct tty_port *__tport = &__port->state->port;		      \
 921	unsigned int pending;						      \
 922									      \
 923	for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) {   \
 924		if (__port->x_char) {					      \
 925			(ch) = __port->x_char;				      \
 926			(put_char);					      \
 927			__port->x_char = 0;				      \
 928			continue;					      \
 929		}							      \
 930									      \
 931		if (uart_tx_stopped(__port))				      \
 932			break;						      \
 933									      \
 934		if (!kfifo_get(&__tport->xmit_fifo, &(ch)))		      \
 935			break;						      \
 936									      \
 937		(put_char);						      \
 938	}								      \
 939									      \
 940	(tx_done);							      \
 941									      \
 942	pending = kfifo_len(&__tport->xmit_fifo);			      \
 943	if (pending < WAKEUP_CHARS) {					      \
 944		uart_write_wakeup(__port);				      \
 945									      \
 946		if (!((flags) & UART_TX_NOSTOP) && pending == 0)	      \
 947			__port->ops->stop_tx(__port);			      \
 948	}								      \
 949									      \
 950	pending;							      \
 951})
 952
 953/**
 954 * uart_port_tx_limited -- transmit helper for uart_port with count limiting
 955 * @port: uart port
 956 * @ch: variable to store a character to be written to the HW
 957 * @count: a limit of characters to send
 958 * @tx_ready: can HW accept more data function
 959 * @put_char: function to write a character
 960 * @tx_done: function to call after the loop is done
 961 *
 962 * This helper transmits characters from the xmit buffer to the hardware using
 963 * @put_char(). It does so until @count characters are sent and while @tx_ready
 964 * evaluates to true.
 965 *
 966 * Returns: the number of characters in the xmit buffer when done.
 967 *
 968 * The expression in macro parameters shall be designed as follows:
 969 *  * **tx_ready:** should evaluate to true if the HW can accept more data to
 970 *    be sent. This parameter can be %true, which means the HW is always ready.
 971 *  * **put_char:** shall write @ch to the device of @port.
 972 *  * **tx_done:** when the write loop is done, this can perform arbitrary
 973 *    action before potential invocation of ops->stop_tx() happens. If the
 974 *    driver does not need to do anything, use e.g. ({}).
 975 *
 976 * For all of them, @port->lock is held, interrupts are locally disabled and
 977 * the expressions must not sleep.
 978 */
 979#define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \
 980	unsigned int __count = (count);					      \
 981	__uart_port_tx(port, ch, 0, tx_ready, put_char, tx_done, __count,     \
 982			__count--);					      \
 983})
 984
 985/**
 986 * uart_port_tx_limited_flags -- transmit helper for uart_port with count limiting with flags
 987 * @port: uart port
 988 * @ch: variable to store a character to be written to the HW
 989 * @flags: %UART_TX_NOSTOP or similar
 990 * @count: a limit of characters to send
 991 * @tx_ready: can HW accept more data function
 992 * @put_char: function to write a character
 993 * @tx_done: function to call after the loop is done
 994 *
 995 * See uart_port_tx_limited() for more details.
 996 */
 997#define uart_port_tx_limited_flags(port, ch, flags, count, tx_ready, put_char, tx_done) ({ \
 998	unsigned int __count = (count);							   \
 999	__uart_port_tx(port, ch, flags, tx_ready, put_char, tx_done, __count,		   \
1000			__count--);							   \
1001})
1002
1003/**
1004 * uart_port_tx -- transmit helper for uart_port
1005 * @port: uart port
1006 * @ch: variable to store a character to be written to the HW
1007 * @tx_ready: can HW accept more data function
1008 * @put_char: function to write a character
1009 *
1010 * See uart_port_tx_limited() for more details.
1011 */
1012#define uart_port_tx(port, ch, tx_ready, put_char)			\
1013	__uart_port_tx(port, ch, 0, tx_ready, put_char, ({}), true, ({}))
1014
1015
1016/**
1017 * uart_port_tx_flags -- transmit helper for uart_port with flags
1018 * @port: uart port
1019 * @ch: variable to store a character to be written to the HW
1020 * @flags: %UART_TX_NOSTOP or similar
1021 * @tx_ready: can HW accept more data function
1022 * @put_char: function to write a character
1023 *
1024 * See uart_port_tx_limited() for more details.
1025 */
1026#define uart_port_tx_flags(port, ch, flags, tx_ready, put_char)		\
1027	__uart_port_tx(port, ch, flags, tx_ready, put_char, ({}), true, ({}))
1028/*
1029 * Baud rate helpers.
1030 */
1031void uart_update_timeout(struct uart_port *port, unsigned int cflag,
1032			 unsigned int baud);
1033unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
1034				const struct ktermios *old, unsigned int min,
1035				unsigned int max);
1036unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
1037
1038/*
1039 * Calculates FIFO drain time.
1040 */
1041static inline unsigned long uart_fifo_timeout(struct uart_port *port)
1042{
1043	u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize;
1044
1045	/* Add .02 seconds of slop */
1046	fifo_timeout += 20 * NSEC_PER_MSEC;
1047
1048	return max(nsecs_to_jiffies(fifo_timeout), 1UL);
1049}
1050
1051/* Base timer interval for polling */
1052static inline unsigned long uart_poll_timeout(struct uart_port *port)
1053{
1054	unsigned long timeout = uart_fifo_timeout(port);
1055
1056	return timeout > 6 ? (timeout / 2 - 2) : 1;
1057}
1058
1059/*
1060 * Console helpers.
1061 */
1062struct earlycon_device {
1063	struct console *con;
1064	struct uart_port port;
1065	char options[32];		/* e.g., 115200n8 */
1066	unsigned int baud;
1067};
1068
1069struct earlycon_id {
1070	char	name[15];
1071	char	name_term;	/* In case compiler didn't '\0' term name */
1072	char	compatible[128];
1073	int	(*setup)(struct earlycon_device *, const char *options);
1074};
1075
1076extern const struct earlycon_id __earlycon_table[];
1077extern const struct earlycon_id __earlycon_table_end[];
1078
1079#if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
1080#define EARLYCON_USED_OR_UNUSED	__used
1081#else
1082#define EARLYCON_USED_OR_UNUSED	__maybe_unused
1083#endif
1084
1085#define OF_EARLYCON_DECLARE(_name, compat, fn)				\
1086	static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
1087		EARLYCON_USED_OR_UNUSED  __section("__earlycon_table")  \
1088		__aligned(__alignof__(struct earlycon_id))		\
1089		= { .name = __stringify(_name),				\
1090		    .compatible = compat,				\
1091		    .setup = fn }
1092
1093#define EARLYCON_DECLARE(_name, fn)	OF_EARLYCON_DECLARE(_name, "", fn)
1094
1095int of_setup_earlycon(const struct earlycon_id *match, unsigned long node,
1096		      const char *options);
1097
1098#ifdef CONFIG_SERIAL_EARLYCON
1099extern bool earlycon_acpi_spcr_enable __initdata;
1100int setup_earlycon(char *buf);
1101#else
1102static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
1103static inline int setup_earlycon(char *buf) { return 0; }
1104#endif
1105
1106/* Variant of uart_console_registered() when the console_list_lock is held. */
1107static inline bool uart_console_registered_locked(struct uart_port *port)
1108{
1109	return uart_console(port) && console_is_registered_locked(port->cons);
1110}
1111
1112static inline bool uart_console_registered(struct uart_port *port)
1113{
1114	return uart_console(port) && console_is_registered(port->cons);
1115}
1116
1117int uart_parse_earlycon(char *p, enum uart_iotype *iotype,
1118			resource_size_t *addr, char **options);
1119void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
1120			int *flow);
1121int uart_set_options(struct uart_port *port, struct console *co, int baud,
1122		     int parity, int bits, int flow);
1123struct tty_driver *uart_console_device(struct console *co, int *index);
1124void uart_console_write(struct uart_port *port, const char *s,
1125			unsigned int count,
1126			void (*putchar)(struct uart_port *, unsigned char));
1127
1128/*
1129 * Port/driver registration/removal
1130 */
1131int uart_register_driver(struct uart_driver *uart);
1132void uart_unregister_driver(struct uart_driver *uart);
1133int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
1134void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
1135int uart_read_port_properties(struct uart_port *port);
1136int uart_read_and_validate_port_properties(struct uart_port *port);
1137bool uart_match_port(const struct uart_port *port1,
1138		const struct uart_port *port2);
1139
1140/*
1141 * Power Management
1142 */
1143int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
1144int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
1145
1146static inline int uart_tx_stopped(struct uart_port *port)
1147{
1148	struct tty_struct *tty = port->state->port.tty;
1149	if ((tty && tty->flow.stopped) || port->hw_stopped)
1150		return 1;
1151	return 0;
1152}
1153
1154static inline bool uart_cts_enabled(struct uart_port *uport)
1155{
1156	return !!(uport->status & UPSTAT_CTS_ENABLE);
1157}
1158
1159static inline bool uart_softcts_mode(struct uart_port *uport)
1160{
1161	upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
1162
1163	return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
1164}
1165
1166/*
1167 * The following are helper functions for the low level drivers.
1168 */
1169
1170void uart_handle_dcd_change(struct uart_port *uport, bool active);
1171void uart_handle_cts_change(struct uart_port *uport, bool active);
1172
1173void uart_insert_char(struct uart_port *port, unsigned int status,
1174		      unsigned int overrun, u8 ch, u8 flag);
1175
1176void uart_xchar_out(struct uart_port *uport, int offset);
1177
1178#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1179#define SYSRQ_TIMEOUT	(HZ * 5)
1180
1181bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch);
1182
1183static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
1184{
1185	if (!port->sysrq)
1186		return 0;
1187
1188	if (ch && time_before(jiffies, port->sysrq)) {
1189		if (sysrq_mask()) {
1190			handle_sysrq(ch);
1191			port->sysrq = 0;
1192			return 1;
1193		}
1194		if (uart_try_toggle_sysrq(port, ch))
1195			return 1;
1196	}
1197	port->sysrq = 0;
1198
1199	return 0;
1200}
1201
1202static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
1203{
1204	if (!port->sysrq)
1205		return 0;
1206
1207	if (ch && time_before(jiffies, port->sysrq)) {
1208		if (sysrq_mask()) {
1209			port->sysrq_ch = ch;
1210			port->sysrq = 0;
1211			return 1;
1212		}
1213		if (uart_try_toggle_sysrq(port, ch))
1214			return 1;
1215	}
1216	port->sysrq = 0;
1217
1218	return 0;
1219}
1220
1221static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1222{
1223	u8 sysrq_ch;
1224
1225	if (!port->has_sysrq) {
1226		uart_port_unlock(port);
1227		return;
1228	}
1229
1230	sysrq_ch = port->sysrq_ch;
1231	port->sysrq_ch = 0;
1232
1233	uart_port_unlock(port);
1234
1235	if (sysrq_ch)
1236		handle_sysrq(sysrq_ch);
1237}
1238
1239static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1240		unsigned long flags)
1241{
1242	u8 sysrq_ch;
1243
1244	if (!port->has_sysrq) {
1245		uart_port_unlock_irqrestore(port, flags);
1246		return;
1247	}
1248
1249	sysrq_ch = port->sysrq_ch;
1250	port->sysrq_ch = 0;
1251
1252	uart_port_unlock_irqrestore(port, flags);
1253
1254	if (sysrq_ch)
1255		handle_sysrq(sysrq_ch);
1256}
1257#else	/* CONFIG_MAGIC_SYSRQ_SERIAL */
1258static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
1259{
1260	return 0;
1261}
1262static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
1263{
1264	return 0;
1265}
1266static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1267{
1268	uart_port_unlock(port);
1269}
1270static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1271		unsigned long flags)
1272{
1273	uart_port_unlock_irqrestore(port, flags);
1274}
1275#endif	/* CONFIG_MAGIC_SYSRQ_SERIAL */
1276
1277/*
1278 * We do the SysRQ and SAK checking like this...
1279 */
1280static inline int uart_handle_break(struct uart_port *port)
1281{
1282	struct uart_state *state = port->state;
1283
1284	if (port->handle_break)
1285		port->handle_break(port);
1286
1287#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1288	if (port->has_sysrq && uart_console(port)) {
1289		if (!port->sysrq) {
1290			port->sysrq = jiffies + SYSRQ_TIMEOUT;
1291			return 1;
1292		}
1293		port->sysrq = 0;
1294	}
1295#endif
1296	if (port->flags & UPF_SAK)
1297		do_SAK(state->port.tty);
1298	return 0;
1299}
1300
1301/*
1302 *	UART_ENABLE_MS - determine if port should enable modem status irqs
1303 */
1304#define UART_ENABLE_MS(port,cflag)	((port)->flags & UPF_HARDPPS_CD || \
1305					 (cflag) & CRTSCTS || \
1306					 !((cflag) & CLOCAL))
1307
1308int uart_get_rs485_mode(struct uart_port *port);
1309#endif /* LINUX_SERIAL_CORE_H */