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  
30  struct uart_port;
31  struct serial_struct;
32  struct serial_port_device;
33  struct device;
34  struct 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   */
375  struct 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  
413  struct 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  
427  typedef u64 __bitwise upf_t;
428  typedef unsigned int __bitwise upstat_t;
429  
430  struct uart_port {
431  	spinlock_t		lock;			/* port lock */
432  	unsigned long		iobase;			/* in/out[bwl] */
433  	unsigned char __iomem	*membase;		/* read/write[bwl] */
434  	unsigned int		(*serial_in)(struct uart_port *, int);
435  	void			(*serial_out)(struct uart_port *, int, int);
436  	void			(*set_termios)(struct uart_port *,
437  				               struct ktermios *new,
438  				               const struct ktermios *old);
439  	void			(*set_ldisc)(struct uart_port *,
440  					     struct ktermios *);
441  	unsigned int		(*get_mctrl)(struct uart_port *);
442  	void			(*set_mctrl)(struct uart_port *, unsigned int);
443  	unsigned int		(*get_divisor)(struct uart_port *,
444  					       unsigned int baud,
445  					       unsigned int *frac);
446  	void			(*set_divisor)(struct uart_port *,
447  					       unsigned int baud,
448  					       unsigned int quot,
449  					       unsigned int quot_frac);
450  	int			(*startup)(struct uart_port *port);
451  	void			(*shutdown)(struct uart_port *port);
452  	void			(*throttle)(struct uart_port *port);
453  	void			(*unthrottle)(struct uart_port *port);
454  	int			(*handle_irq)(struct uart_port *);
455  	void			(*pm)(struct uart_port *, unsigned int state,
456  				      unsigned int old);
457  	void			(*handle_break)(struct uart_port *);
458  	int			(*rs485_config)(struct uart_port *,
459  						struct ktermios *termios,
460  						struct serial_rs485 *rs485);
461  	int			(*iso7816_config)(struct uart_port *,
462  						  struct serial_iso7816 *iso7816);
463  	unsigned int		ctrl_id;		/* optional serial core controller id */
464  	unsigned int		port_id;		/* optional serial core port id */
465  	unsigned int		irq;			/* irq number */
466  	unsigned long		irqflags;		/* irq flags  */
467  	unsigned int		uartclk;		/* base uart clock */
468  	unsigned int		fifosize;		/* tx fifo size */
469  	unsigned char		x_char;			/* xon/xoff char */
470  	unsigned char		regshift;		/* reg offset shift */
471  
472  	unsigned char		iotype;			/* io access style */
473  
474  #define UPIO_UNKNOWN		((unsigned char)~0U)	/* UCHAR_MAX */
475  #define UPIO_PORT		(SERIAL_IO_PORT)	/* 8b I/O port access */
476  #define UPIO_HUB6		(SERIAL_IO_HUB6)	/* Hub6 ISA card */
477  #define UPIO_MEM		(SERIAL_IO_MEM)		/* driver-specific */
478  #define UPIO_MEM32		(SERIAL_IO_MEM32)	/* 32b little endian */
479  #define UPIO_AU			(SERIAL_IO_AU)		/* Au1x00 and RT288x type IO */
480  #define UPIO_TSI		(SERIAL_IO_TSI)		/* Tsi108/109 type IO */
481  #define UPIO_MEM32BE		(SERIAL_IO_MEM32BE)	/* 32b big endian */
482  #define UPIO_MEM16		(SERIAL_IO_MEM16)	/* 16b little endian */
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  	unsigned int		read_status_mask;	/* driver specific */
490  	unsigned int		ignore_status_mask;	/* driver specific */
491  	struct uart_state	*state;			/* pointer to parent state */
492  	struct uart_icount	icount;			/* statistics */
493  
494  	struct console		*cons;			/* struct console, if any */
495  	/* flags must be updated while holding port mutex */
496  	upf_t			flags;
497  
498  	/*
499  	 * These flags must be equivalent to the flags defined in
500  	 * include/uapi/linux/tty_flags.h which are the userspace definitions
501  	 * assigned from the serial_struct flags in uart_set_info()
502  	 * [for bit definitions in the UPF_CHANGE_MASK]
503  	 *
504  	 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable
505  	 * The remaining bits are serial-core specific and not modifiable by
506  	 * userspace.
507  	 */
508  #define UPF_FOURPORT		((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
509  #define UPF_SAK			((__force upf_t) ASYNC_SAK            /* 2  */ )
510  #define UPF_SPD_HI		((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
511  #define UPF_SPD_VHI		((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
512  #define UPF_SPD_CUST		((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
513  #define UPF_SPD_WARP		((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
514  #define UPF_SPD_MASK		((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
515  #define UPF_SKIP_TEST		((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
516  #define UPF_AUTO_IRQ		((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
517  #define UPF_HARDPPS_CD		((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
518  #define UPF_SPD_SHI		((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
519  #define UPF_LOW_LATENCY		((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
520  #define UPF_BUGGY_UART		((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
521  #define UPF_MAGIC_MULTIPLIER	((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
522  
523  #define UPF_NO_THRE_TEST	((__force upf_t) BIT_ULL(19))
524  /* Port has hardware-assisted h/w flow control */
525  #define UPF_AUTO_CTS		((__force upf_t) BIT_ULL(20))
526  #define UPF_AUTO_RTS		((__force upf_t) BIT_ULL(21))
527  #define UPF_HARD_FLOW		((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
528  /* Port has hardware-assisted s/w flow control */
529  #define UPF_SOFT_FLOW		((__force upf_t) BIT_ULL(22))
530  #define UPF_CONS_FLOW		((__force upf_t) BIT_ULL(23))
531  #define UPF_SHARE_IRQ		((__force upf_t) BIT_ULL(24))
532  #define UPF_EXAR_EFR		((__force upf_t) BIT_ULL(25))
533  #define UPF_BUG_THRE		((__force upf_t) BIT_ULL(26))
534  /* The exact UART type is known and should not be probed.  */
535  #define UPF_FIXED_TYPE		((__force upf_t) BIT_ULL(27))
536  #define UPF_BOOT_AUTOCONF	((__force upf_t) BIT_ULL(28))
537  #define UPF_FIXED_PORT		((__force upf_t) BIT_ULL(29))
538  #define UPF_DEAD		((__force upf_t) BIT_ULL(30))
539  #define UPF_IOREMAP		((__force upf_t) BIT_ULL(31))
540  #define UPF_FULL_PROBE		((__force upf_t) BIT_ULL(32))
541  
542  #define __UPF_CHANGE_MASK	0x17fff
543  #define UPF_CHANGE_MASK		((__force upf_t) __UPF_CHANGE_MASK)
544  #define UPF_USR_MASK		((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
545  
546  #if __UPF_CHANGE_MASK > ASYNC_FLAGS
547  #error Change mask not equivalent to userspace-visible bit defines
548  #endif
549  
550  	/*
551  	 * Must hold termios_rwsem, port mutex and port lock to change;
552  	 * can hold any one lock to read.
553  	 */
554  	upstat_t		status;
555  
556  #define UPSTAT_CTS_ENABLE	((__force upstat_t) (1 << 0))
557  #define UPSTAT_DCD_ENABLE	((__force upstat_t) (1 << 1))
558  #define UPSTAT_AUTORTS		((__force upstat_t) (1 << 2))
559  #define UPSTAT_AUTOCTS		((__force upstat_t) (1 << 3))
560  #define UPSTAT_AUTOXOFF		((__force upstat_t) (1 << 4))
561  #define UPSTAT_SYNC_FIFO	((__force upstat_t) (1 << 5))
562  
563  	bool			hw_stopped;		/* sw-assisted CTS flow state */
564  	unsigned int		mctrl;			/* current modem ctrl settings */
565  	unsigned int		frame_time;		/* frame timing in ns */
566  	unsigned int		type;			/* port type */
567  	const struct uart_ops	*ops;
568  	unsigned int		custom_divisor;
569  	unsigned int		line;			/* port index */
570  	unsigned int		minor;
571  	resource_size_t		mapbase;		/* for ioremap */
572  	resource_size_t		mapsize;
573  	struct device		*dev;			/* serial port physical parent device */
574  	struct serial_port_device *port_dev;		/* serial core port device */
575  
576  	unsigned long		sysrq;			/* sysrq timeout */
577  	u8			sysrq_ch;		/* char for sysrq */
578  	unsigned char		has_sysrq;
579  	unsigned char		sysrq_seq;		/* index in sysrq_toggle_seq */
580  
581  	unsigned char		hub6;			/* this should be in the 8250 driver */
582  	unsigned char		suspended;
583  	unsigned char		console_reinit;
584  	const char		*name;			/* port name */
585  	struct attribute_group	*attr_group;		/* port specific attributes */
586  	const struct attribute_group **tty_groups;	/* all attributes (serial core use only) */
587  	struct serial_rs485     rs485;
588  	struct serial_rs485	rs485_supported;	/* Supported mask for serial_rs485 */
589  	struct gpio_desc	*rs485_term_gpio;	/* enable RS485 bus termination */
590  	struct gpio_desc	*rs485_rx_during_tx_gpio; /* Output GPIO that sets the state of RS485 RX during TX */
591  	struct serial_iso7816   iso7816;
592  	void			*private_data;		/* generic platform data pointer */
593  };
594  
595  /*
596   * Only for console->device_lock()/_unlock() callbacks and internal
597   * port lock wrapper synchronization.
598   */
__uart_port_lock_irqsave(struct uart_port * up,unsigned long * flags)599  static inline void __uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags)
600  {
601  	spin_lock_irqsave(&up->lock, *flags);
602  }
603  
604  /*
605   * Only for console->device_lock()/_unlock() callbacks and internal
606   * port lock wrapper synchronization.
607   */
__uart_port_unlock_irqrestore(struct uart_port * up,unsigned long flags)608  static inline void __uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags)
609  {
610  	spin_unlock_irqrestore(&up->lock, flags);
611  }
612  
613  /**
614   * uart_port_set_cons - Safely set the @cons field for a uart
615   * @up:		The uart port to set
616   * @con:	The new console to set to
617   *
618   * This function must be used to set @up->cons. It uses the port lock to
619   * synchronize with the port lock wrappers in order to ensure that the console
620   * cannot change or disappear while another context is holding the port lock.
621   */
uart_port_set_cons(struct uart_port * up,struct console * con)622  static inline void uart_port_set_cons(struct uart_port *up, struct console *con)
623  {
624  	unsigned long flags;
625  
626  	__uart_port_lock_irqsave(up, &flags);
627  	up->cons = con;
628  	__uart_port_unlock_irqrestore(up, flags);
629  }
630  
631  /* Only for internal port lock wrapper usage. */
__uart_port_using_nbcon(struct uart_port * up)632  static inline bool __uart_port_using_nbcon(struct uart_port *up)
633  {
634  	lockdep_assert_held_once(&up->lock);
635  
636  	if (likely(!uart_console(up)))
637  		return false;
638  
639  	/*
640  	 * @up->cons is only modified under the port lock. Therefore it is
641  	 * certain that it cannot disappear here.
642  	 *
643  	 * @up->cons->node is added/removed from the console list under the
644  	 * port lock. Therefore it is certain that the registration status
645  	 * cannot change here, thus @up->cons->flags can be read directly.
646  	 */
647  	if (hlist_unhashed_lockless(&up->cons->node) ||
648  	    !(up->cons->flags & CON_NBCON) ||
649  	    !up->cons->write_atomic) {
650  		return false;
651  	}
652  
653  	return true;
654  }
655  
656  /* Only for internal port lock wrapper usage. */
__uart_port_nbcon_try_acquire(struct uart_port * up)657  static inline bool __uart_port_nbcon_try_acquire(struct uart_port *up)
658  {
659  	if (!__uart_port_using_nbcon(up))
660  		return true;
661  
662  	return nbcon_device_try_acquire(up->cons);
663  }
664  
665  /* Only for internal port lock wrapper usage. */
__uart_port_nbcon_acquire(struct uart_port * up)666  static inline void __uart_port_nbcon_acquire(struct uart_port *up)
667  {
668  	if (!__uart_port_using_nbcon(up))
669  		return;
670  
671  	while (!nbcon_device_try_acquire(up->cons))
672  		cpu_relax();
673  }
674  
675  /* Only for internal port lock wrapper usage. */
__uart_port_nbcon_release(struct uart_port * up)676  static inline void __uart_port_nbcon_release(struct uart_port *up)
677  {
678  	if (!__uart_port_using_nbcon(up))
679  		return;
680  
681  	nbcon_device_release(up->cons);
682  }
683  
684  /**
685   * uart_port_lock - Lock the UART port
686   * @up:		Pointer to UART port structure
687   */
uart_port_lock(struct uart_port * up)688  static inline void uart_port_lock(struct uart_port *up)
689  {
690  	spin_lock(&up->lock);
691  	__uart_port_nbcon_acquire(up);
692  }
693  
694  /**
695   * uart_port_lock_irq - Lock the UART port and disable interrupts
696   * @up:		Pointer to UART port structure
697   */
uart_port_lock_irq(struct uart_port * up)698  static inline void uart_port_lock_irq(struct uart_port *up)
699  {
700  	spin_lock_irq(&up->lock);
701  	__uart_port_nbcon_acquire(up);
702  }
703  
704  /**
705   * uart_port_lock_irqsave - Lock the UART port, save and disable interrupts
706   * @up:		Pointer to UART port structure
707   * @flags:	Pointer to interrupt flags storage
708   */
uart_port_lock_irqsave(struct uart_port * up,unsigned long * flags)709  static inline void uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags)
710  {
711  	spin_lock_irqsave(&up->lock, *flags);
712  	__uart_port_nbcon_acquire(up);
713  }
714  
715  /**
716   * uart_port_trylock - Try to lock the UART port
717   * @up:		Pointer to UART port structure
718   *
719   * Returns: True if lock was acquired, false otherwise
720   */
uart_port_trylock(struct uart_port * up)721  static inline bool uart_port_trylock(struct uart_port *up)
722  {
723  	if (!spin_trylock(&up->lock))
724  		return false;
725  
726  	if (!__uart_port_nbcon_try_acquire(up)) {
727  		spin_unlock(&up->lock);
728  		return false;
729  	}
730  
731  	return true;
732  }
733  
734  /**
735   * uart_port_trylock_irqsave - Try to lock the UART port, save and disable interrupts
736   * @up:		Pointer to UART port structure
737   * @flags:	Pointer to interrupt flags storage
738   *
739   * Returns: True if lock was acquired, false otherwise
740   */
uart_port_trylock_irqsave(struct uart_port * up,unsigned long * flags)741  static inline bool uart_port_trylock_irqsave(struct uart_port *up, unsigned long *flags)
742  {
743  	if (!spin_trylock_irqsave(&up->lock, *flags))
744  		return false;
745  
746  	if (!__uart_port_nbcon_try_acquire(up)) {
747  		spin_unlock_irqrestore(&up->lock, *flags);
748  		return false;
749  	}
750  
751  	return true;
752  }
753  
754  /**
755   * uart_port_unlock - Unlock the UART port
756   * @up:		Pointer to UART port structure
757   */
uart_port_unlock(struct uart_port * up)758  static inline void uart_port_unlock(struct uart_port *up)
759  {
760  	__uart_port_nbcon_release(up);
761  	spin_unlock(&up->lock);
762  }
763  
764  /**
765   * uart_port_unlock_irq - Unlock the UART port and re-enable interrupts
766   * @up:		Pointer to UART port structure
767   */
uart_port_unlock_irq(struct uart_port * up)768  static inline void uart_port_unlock_irq(struct uart_port *up)
769  {
770  	__uart_port_nbcon_release(up);
771  	spin_unlock_irq(&up->lock);
772  }
773  
774  /**
775   * uart_port_unlock_irqrestore - Unlock the UART port, restore interrupts
776   * @up:		Pointer to UART port structure
777   * @flags:	The saved interrupt flags for restore
778   */
uart_port_unlock_irqrestore(struct uart_port * up,unsigned long flags)779  static inline void uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags)
780  {
781  	__uart_port_nbcon_release(up);
782  	spin_unlock_irqrestore(&up->lock, flags);
783  }
784  
serial_port_in(struct uart_port * up,int offset)785  static inline int serial_port_in(struct uart_port *up, int offset)
786  {
787  	return up->serial_in(up, offset);
788  }
789  
serial_port_out(struct uart_port * up,int offset,int value)790  static inline void serial_port_out(struct uart_port *up, int offset, int value)
791  {
792  	up->serial_out(up, offset, value);
793  }
794  
795  /**
796   * enum uart_pm_state - power states for UARTs
797   * @UART_PM_STATE_ON: UART is powered, up and operational
798   * @UART_PM_STATE_OFF: UART is powered off
799   * @UART_PM_STATE_UNDEFINED: sentinel
800   */
801  enum uart_pm_state {
802  	UART_PM_STATE_ON = 0,
803  	UART_PM_STATE_OFF = 3, /* number taken from ACPI */
804  	UART_PM_STATE_UNDEFINED,
805  };
806  
807  /*
808   * This is the state information which is persistent across opens.
809   */
810  struct uart_state {
811  	struct tty_port		port;
812  
813  	enum uart_pm_state	pm_state;
814  
815  	atomic_t		refcount;
816  	wait_queue_head_t	remove_wait;
817  	struct uart_port	*uart_port;
818  };
819  
820  #define UART_XMIT_SIZE	PAGE_SIZE
821  
822  
823  /* number of characters left in xmit buffer before we ask for more */
824  #define WAKEUP_CHARS		256
825  
826  /**
827   * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
828   * @up: uart_port structure describing the port
829   * @chars: number of characters sent
830   *
831   * This function advances the tail of circular xmit buffer by the number of
832   * @chars transmitted and handles accounting of transmitted bytes (into
833   * @up's icount.tx).
834   */
uart_xmit_advance(struct uart_port * up,unsigned int chars)835  static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars)
836  {
837  	struct tty_port *tport = &up->state->port;
838  
839  	kfifo_skip_count(&tport->xmit_fifo, chars);
840  	up->icount.tx += chars;
841  }
842  
uart_fifo_out(struct uart_port * up,unsigned char * buf,unsigned int chars)843  static inline unsigned int uart_fifo_out(struct uart_port *up,
844  		unsigned char *buf, unsigned int chars)
845  {
846  	struct tty_port *tport = &up->state->port;
847  
848  	chars = kfifo_out(&tport->xmit_fifo, buf, chars);
849  	up->icount.tx += chars;
850  
851  	return chars;
852  }
853  
uart_fifo_get(struct uart_port * up,unsigned char * ch)854  static inline unsigned int uart_fifo_get(struct uart_port *up,
855  		unsigned char *ch)
856  {
857  	struct tty_port *tport = &up->state->port;
858  	unsigned int chars;
859  
860  	chars = kfifo_get(&tport->xmit_fifo, ch);
861  	up->icount.tx += chars;
862  
863  	return chars;
864  }
865  
866  struct module;
867  struct tty_driver;
868  
869  struct uart_driver {
870  	struct module		*owner;
871  	const char		*driver_name;
872  	const char		*dev_name;
873  	int			 major;
874  	int			 minor;
875  	int			 nr;
876  	struct console		*cons;
877  
878  	/*
879  	 * these are private; the low level driver should not
880  	 * touch these; they should be initialised to NULL
881  	 */
882  	struct uart_state	*state;
883  	struct tty_driver	*tty_driver;
884  };
885  
886  void uart_write_wakeup(struct uart_port *port);
887  
888  /**
889   * enum UART_TX_FLAGS -- flags for uart_port_tx_flags()
890   *
891   * @UART_TX_NOSTOP: don't call port->ops->stop_tx() on empty buffer
892   */
893  enum UART_TX_FLAGS {
894  	UART_TX_NOSTOP = BIT(0),
895  };
896  
897  #define __uart_port_tx(uport, ch, flags, tx_ready, put_char, tx_done,	      \
898  		       for_test, for_post)				      \
899  ({									      \
900  	struct uart_port *__port = (uport);				      \
901  	struct tty_port *__tport = &__port->state->port;		      \
902  	unsigned int pending;						      \
903  									      \
904  	for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) {   \
905  		if (__port->x_char) {					      \
906  			(ch) = __port->x_char;				      \
907  			(put_char);					      \
908  			__port->x_char = 0;				      \
909  			continue;					      \
910  		}							      \
911  									      \
912  		if (uart_tx_stopped(__port))				      \
913  			break;						      \
914  									      \
915  		if (!kfifo_get(&__tport->xmit_fifo, &(ch)))		      \
916  			break;						      \
917  									      \
918  		(put_char);						      \
919  	}								      \
920  									      \
921  	(tx_done);							      \
922  									      \
923  	pending = kfifo_len(&__tport->xmit_fifo);			      \
924  	if (pending < WAKEUP_CHARS) {					      \
925  		uart_write_wakeup(__port);				      \
926  									      \
927  		if (!((flags) & UART_TX_NOSTOP) && pending == 0)	      \
928  			__port->ops->stop_tx(__port);			      \
929  	}								      \
930  									      \
931  	pending;							      \
932  })
933  
934  /**
935   * uart_port_tx_limited -- transmit helper for uart_port with count limiting
936   * @port: uart port
937   * @ch: variable to store a character to be written to the HW
938   * @count: a limit of characters to send
939   * @tx_ready: can HW accept more data function
940   * @put_char: function to write a character
941   * @tx_done: function to call after the loop is done
942   *
943   * This helper transmits characters from the xmit buffer to the hardware using
944   * @put_char(). It does so until @count characters are sent and while @tx_ready
945   * evaluates to true.
946   *
947   * Returns: the number of characters in the xmit buffer when done.
948   *
949   * The expression in macro parameters shall be designed as follows:
950   *  * **tx_ready:** should evaluate to true if the HW can accept more data to
951   *    be sent. This parameter can be %true, which means the HW is always ready.
952   *  * **put_char:** shall write @ch to the device of @port.
953   *  * **tx_done:** when the write loop is done, this can perform arbitrary
954   *    action before potential invocation of ops->stop_tx() happens. If the
955   *    driver does not need to do anything, use e.g. ({}).
956   *
957   * For all of them, @port->lock is held, interrupts are locally disabled and
958   * the expressions must not sleep.
959   */
960  #define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \
961  	unsigned int __count = (count);					      \
962  	__uart_port_tx(port, ch, 0, tx_ready, put_char, tx_done, __count,     \
963  			__count--);					      \
964  })
965  
966  /**
967   * uart_port_tx_limited_flags -- transmit helper for uart_port with count limiting with flags
968   * @port: uart port
969   * @ch: variable to store a character to be written to the HW
970   * @flags: %UART_TX_NOSTOP or similar
971   * @count: a limit of characters to send
972   * @tx_ready: can HW accept more data function
973   * @put_char: function to write a character
974   * @tx_done: function to call after the loop is done
975   *
976   * See uart_port_tx_limited() for more details.
977   */
978  #define uart_port_tx_limited_flags(port, ch, flags, count, tx_ready, put_char, tx_done) ({ \
979  	unsigned int __count = (count);							   \
980  	__uart_port_tx(port, ch, flags, tx_ready, put_char, tx_done, __count,		   \
981  			__count--);							   \
982  })
983  
984  /**
985   * uart_port_tx -- transmit helper for uart_port
986   * @port: uart port
987   * @ch: variable to store a character to be written to the HW
988   * @tx_ready: can HW accept more data function
989   * @put_char: function to write a character
990   *
991   * See uart_port_tx_limited() for more details.
992   */
993  #define uart_port_tx(port, ch, tx_ready, put_char)			\
994  	__uart_port_tx(port, ch, 0, tx_ready, put_char, ({}), true, ({}))
995  
996  
997  /**
998   * uart_port_tx_flags -- transmit helper for uart_port with flags
999   * @port: uart port
1000   * @ch: variable to store a character to be written to the HW
1001   * @flags: %UART_TX_NOSTOP or similar
1002   * @tx_ready: can HW accept more data function
1003   * @put_char: function to write a character
1004   *
1005   * See uart_port_tx_limited() for more details.
1006   */
1007  #define uart_port_tx_flags(port, ch, flags, tx_ready, put_char)		\
1008  	__uart_port_tx(port, ch, flags, tx_ready, put_char, ({}), true, ({}))
1009  /*
1010   * Baud rate helpers.
1011   */
1012  void uart_update_timeout(struct uart_port *port, unsigned int cflag,
1013  			 unsigned int baud);
1014  unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
1015  				const struct ktermios *old, unsigned int min,
1016  				unsigned int max);
1017  unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
1018  
1019  /*
1020   * Calculates FIFO drain time.
1021   */
uart_fifo_timeout(struct uart_port * port)1022  static inline unsigned long uart_fifo_timeout(struct uart_port *port)
1023  {
1024  	u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize;
1025  
1026  	/* Add .02 seconds of slop */
1027  	fifo_timeout += 20 * NSEC_PER_MSEC;
1028  
1029  	return max(nsecs_to_jiffies(fifo_timeout), 1UL);
1030  }
1031  
1032  /* Base timer interval for polling */
uart_poll_timeout(struct uart_port * port)1033  static inline unsigned long uart_poll_timeout(struct uart_port *port)
1034  {
1035  	unsigned long timeout = uart_fifo_timeout(port);
1036  
1037  	return timeout > 6 ? (timeout / 2 - 2) : 1;
1038  }
1039  
1040  /*
1041   * Console helpers.
1042   */
1043  struct earlycon_device {
1044  	struct console *con;
1045  	struct uart_port port;
1046  	char options[32];		/* e.g., 115200n8 */
1047  	unsigned int baud;
1048  };
1049  
1050  struct earlycon_id {
1051  	char	name[15];
1052  	char	name_term;	/* In case compiler didn't '\0' term name */
1053  	char	compatible[128];
1054  	int	(*setup)(struct earlycon_device *, const char *options);
1055  };
1056  
1057  extern const struct earlycon_id __earlycon_table[];
1058  extern const struct earlycon_id __earlycon_table_end[];
1059  
1060  #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
1061  #define EARLYCON_USED_OR_UNUSED	__used
1062  #else
1063  #define EARLYCON_USED_OR_UNUSED	__maybe_unused
1064  #endif
1065  
1066  #define OF_EARLYCON_DECLARE(_name, compat, fn)				\
1067  	static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
1068  		EARLYCON_USED_OR_UNUSED  __section("__earlycon_table")  \
1069  		__aligned(__alignof__(struct earlycon_id))		\
1070  		= { .name = __stringify(_name),				\
1071  		    .compatible = compat,				\
1072  		    .setup = fn }
1073  
1074  #define EARLYCON_DECLARE(_name, fn)	OF_EARLYCON_DECLARE(_name, "", fn)
1075  
1076  int of_setup_earlycon(const struct earlycon_id *match, unsigned long node,
1077  		      const char *options);
1078  
1079  #ifdef CONFIG_SERIAL_EARLYCON
1080  extern bool earlycon_acpi_spcr_enable __initdata;
1081  int setup_earlycon(char *buf);
1082  #else
1083  static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
setup_earlycon(char * buf)1084  static inline int setup_earlycon(char *buf) { return 0; }
1085  #endif
1086  
1087  /* Variant of uart_console_registered() when the console_list_lock is held. */
uart_console_registered_locked(struct uart_port * port)1088  static inline bool uart_console_registered_locked(struct uart_port *port)
1089  {
1090  	return uart_console(port) && console_is_registered_locked(port->cons);
1091  }
1092  
uart_console_registered(struct uart_port * port)1093  static inline bool uart_console_registered(struct uart_port *port)
1094  {
1095  	return uart_console(port) && console_is_registered(port->cons);
1096  }
1097  
1098  struct uart_port *uart_get_console(struct uart_port *ports, int nr,
1099  				   struct console *c);
1100  int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1101  			char **options);
1102  void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
1103  			int *flow);
1104  int uart_set_options(struct uart_port *port, struct console *co, int baud,
1105  		     int parity, int bits, int flow);
1106  struct tty_driver *uart_console_device(struct console *co, int *index);
1107  void uart_console_write(struct uart_port *port, const char *s,
1108  			unsigned int count,
1109  			void (*putchar)(struct uart_port *, unsigned char));
1110  
1111  /*
1112   * Port/driver registration/removal
1113   */
1114  int uart_register_driver(struct uart_driver *uart);
1115  void uart_unregister_driver(struct uart_driver *uart);
1116  int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
1117  void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
1118  int uart_read_port_properties(struct uart_port *port);
1119  int uart_read_and_validate_port_properties(struct uart_port *port);
1120  bool uart_match_port(const struct uart_port *port1,
1121  		const struct uart_port *port2);
1122  
1123  /*
1124   * Power Management
1125   */
1126  int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
1127  int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
1128  
uart_tx_stopped(struct uart_port * port)1129  static inline int uart_tx_stopped(struct uart_port *port)
1130  {
1131  	struct tty_struct *tty = port->state->port.tty;
1132  	if ((tty && tty->flow.stopped) || port->hw_stopped)
1133  		return 1;
1134  	return 0;
1135  }
1136  
uart_cts_enabled(struct uart_port * uport)1137  static inline bool uart_cts_enabled(struct uart_port *uport)
1138  {
1139  	return !!(uport->status & UPSTAT_CTS_ENABLE);
1140  }
1141  
uart_softcts_mode(struct uart_port * uport)1142  static inline bool uart_softcts_mode(struct uart_port *uport)
1143  {
1144  	upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
1145  
1146  	return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
1147  }
1148  
1149  /*
1150   * The following are helper functions for the low level drivers.
1151   */
1152  
1153  void uart_handle_dcd_change(struct uart_port *uport, bool active);
1154  void uart_handle_cts_change(struct uart_port *uport, bool active);
1155  
1156  void uart_insert_char(struct uart_port *port, unsigned int status,
1157  		      unsigned int overrun, u8 ch, u8 flag);
1158  
1159  void uart_xchar_out(struct uart_port *uport, int offset);
1160  
1161  #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1162  #define SYSRQ_TIMEOUT	(HZ * 5)
1163  
1164  bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch);
1165  
uart_handle_sysrq_char(struct uart_port * port,u8 ch)1166  static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
1167  {
1168  	if (!port->sysrq)
1169  		return 0;
1170  
1171  	if (ch && time_before(jiffies, port->sysrq)) {
1172  		if (sysrq_mask()) {
1173  			handle_sysrq(ch);
1174  			port->sysrq = 0;
1175  			return 1;
1176  		}
1177  		if (uart_try_toggle_sysrq(port, ch))
1178  			return 1;
1179  	}
1180  	port->sysrq = 0;
1181  
1182  	return 0;
1183  }
1184  
uart_prepare_sysrq_char(struct uart_port * port,u8 ch)1185  static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
1186  {
1187  	if (!port->sysrq)
1188  		return 0;
1189  
1190  	if (ch && time_before(jiffies, port->sysrq)) {
1191  		if (sysrq_mask()) {
1192  			port->sysrq_ch = ch;
1193  			port->sysrq = 0;
1194  			return 1;
1195  		}
1196  		if (uart_try_toggle_sysrq(port, ch))
1197  			return 1;
1198  	}
1199  	port->sysrq = 0;
1200  
1201  	return 0;
1202  }
1203  
uart_unlock_and_check_sysrq(struct uart_port * port)1204  static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1205  {
1206  	u8 sysrq_ch;
1207  
1208  	if (!port->has_sysrq) {
1209  		uart_port_unlock(port);
1210  		return;
1211  	}
1212  
1213  	sysrq_ch = port->sysrq_ch;
1214  	port->sysrq_ch = 0;
1215  
1216  	uart_port_unlock(port);
1217  
1218  	if (sysrq_ch)
1219  		handle_sysrq(sysrq_ch);
1220  }
1221  
uart_unlock_and_check_sysrq_irqrestore(struct uart_port * port,unsigned long flags)1222  static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1223  		unsigned long flags)
1224  {
1225  	u8 sysrq_ch;
1226  
1227  	if (!port->has_sysrq) {
1228  		uart_port_unlock_irqrestore(port, flags);
1229  		return;
1230  	}
1231  
1232  	sysrq_ch = port->sysrq_ch;
1233  	port->sysrq_ch = 0;
1234  
1235  	uart_port_unlock_irqrestore(port, flags);
1236  
1237  	if (sysrq_ch)
1238  		handle_sysrq(sysrq_ch);
1239  }
1240  #else	/* CONFIG_MAGIC_SYSRQ_SERIAL */
uart_handle_sysrq_char(struct uart_port * port,u8 ch)1241  static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
1242  {
1243  	return 0;
1244  }
uart_prepare_sysrq_char(struct uart_port * port,u8 ch)1245  static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
1246  {
1247  	return 0;
1248  }
uart_unlock_and_check_sysrq(struct uart_port * port)1249  static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1250  {
1251  	uart_port_unlock(port);
1252  }
uart_unlock_and_check_sysrq_irqrestore(struct uart_port * port,unsigned long flags)1253  static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1254  		unsigned long flags)
1255  {
1256  	uart_port_unlock_irqrestore(port, flags);
1257  }
1258  #endif	/* CONFIG_MAGIC_SYSRQ_SERIAL */
1259  
1260  /*
1261   * We do the SysRQ and SAK checking like this...
1262   */
uart_handle_break(struct uart_port * port)1263  static inline int uart_handle_break(struct uart_port *port)
1264  {
1265  	struct uart_state *state = port->state;
1266  
1267  	if (port->handle_break)
1268  		port->handle_break(port);
1269  
1270  #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1271  	if (port->has_sysrq && uart_console(port)) {
1272  		if (!port->sysrq) {
1273  			port->sysrq = jiffies + SYSRQ_TIMEOUT;
1274  			return 1;
1275  		}
1276  		port->sysrq = 0;
1277  	}
1278  #endif
1279  	if (port->flags & UPF_SAK)
1280  		do_SAK(state->port.tty);
1281  	return 0;
1282  }
1283  
1284  /*
1285   *	UART_ENABLE_MS - determine if port should enable modem status irqs
1286   */
1287  #define UART_ENABLE_MS(port,cflag)	((port)->flags & UPF_HARDPPS_CD || \
1288  					 (cflag) & CRTSCTS || \
1289  					 !((cflag) & CLOCAL))
1290  
1291  int uart_get_rs485_mode(struct uart_port *port);
1292  #endif /* LINUX_SERIAL_CORE_H */
1293