2  *  linux/include/linux/console.h
41  *		Invoked by csi_M and printing to the console.
42  * @con_set_palette: sets the palette of the console to @table (optional)
43  * @con_scrolldelta: the contents of the console should be scrolled by @lines.
83 	 * Flush the video console driver's scrollback buffer
87 	 * Prepare the console for the debugger.  This includes, but is not
88 	 * limited to, unblanking the console, loading an appropriate
93 	 * Restore the console to its pre-debug state as closely as possible.
100 extern const struct consw dummy_con;	/* dummy console buffer */
101 extern const struct consw vga_con;	/* VGA text console */
102 extern const struct consw newport_con;	/* SGI Newport console  */
135  * The interface for a console, or any other device that wants to capture
136  * console messages (printer driver?)
140  * cons_flags - General console flags
144  * @CON_CONSDEV:	Indicates that the console driver is backing
145  *			/dev/console.
146  * @CON_ENABLED:	Indicates if a console is allowed to print records. If
147  *			false, the console also will not advance to later
149  * @CON_BOOT:		Marks the console driver as early console driver which
152  *			when the real console driver is registered unless
155  *			that the legacy @console::write callback can be invoked
162  * @CON_EXTENDED:	The console supports the extended output format of
164  * @CON_SUSPENDED:	Indicates if a console is suspended. If true, the
166  * @CON_NBCON:		Console can operate outside of the legacy style console_lock
182  * struct nbcon_state - console state for nbcon consoles
187  * @unsafe:		Console is busy in a non takeover region
189  *			past. The console cannot be safe until re-initialized.
193  * state variable @console::nbcon_state.
214  * are stored in the @console::nbcon_state variable. Ensure this struct stays
221  * nbcon_prio - console owner priority for nbcon consoles
228  * A higher priority context can takeover the console when it is
240 struct console;
244  * struct nbcon_context - Context for console acquire/release
245  * @console:			The associated console
250  *				might cause a system freeze when the console
258 	struct console		*console;  member
273  * @ctxt:		The core console context
286  * struct console - The console descriptor structure
287  * @name:		The name of the console driver
289  * @read:		Read callback for console input (Optional)
291  * @unblank:		Callback to unblank the console (Optional)
292  * @setup:		Callback for initializing the console (Optional)
293  * @exit:		Callback for teardown of the console (Optional)
294  * @match:		Callback for matching a console (Optional)
295  * @flags:		Console flags. See enum cons_flags
296  * @index:		Console index, e.g. port number
303  * @node:		hlist node for the console list
310 struct console {  struct
312 	void			(*write)(struct console *co, const char *s, unsigned int count);  argument
313 	int			(*read)(struct console *co, char *s, unsigned int count);  argument
314 	struct tty_driver	*(*device)(struct console *co, int *index);  argument
316 	int			(*setup)(struct console *co, char *options);  argument
317 	int			(*exit)(struct console *co);  argument
318 	int			(*match)(struct console *co, char *name, int idx, char *options);  argument
329 	/* nbcon console specific members */  argument
330 	bool			(*write_atomic)(struct console *con,  argument
363  * console_srcu_read_flags - Locklessly read the console flags
364  * @con:	struct console pointer of console to read flags from
367  * notation for locklessly reading the console flags. The READ_ONCE()
371  * Only use this function to read console flags when locklessly
372  * iterating the console list via srcu.
376 static inline short console_srcu_read_flags(const struct console *con)  in console_srcu_read_flags()
381 	 * Locklessly reading console->flags provides a consistent  in console_srcu_read_flags()
383 	 * console->flags and that CPU is using only read-modify-write  in console_srcu_read_flags()
390  * console_srcu_write_flags - Write flags for a registered console
391  * @con:	struct console pointer of console to write flags to
399 static inline void console_srcu_write_flags(struct console *con, short flags)  in console_srcu_write_flags()
408 static inline bool console_is_registered_locked(const struct console *con)  in console_is_registered_locked()
415  * console_is_registered - Check if the console is registered
416  * @con:	struct console pointer of console to check
418  * Context: Process context. May sleep while acquiring console list lock.
419  * Return: true if the console is in the console list, otherwise false.
421  * If false is returned for a console that was previously registered, it
422  * can be assumed that the console's unregistration is fully completed,
423  * including the exit() callback after console list removal.
425 static inline bool console_is_registered(const struct console *con)  in console_is_registered()
437  * @con:	struct console pointer used as loop cursor
439  * Although SRCU guarantees the console list will be consistent, the
440  * struct console fields may be updated by other CPUs while iterating.
451  * @con:	struct console pointer used as loop cursor
453  * The console list and the console->flags are immutable while iterating.
472 extern struct console *early_console;
480 extern void console_force_preferred_locked(struct console *con);
481 extern void register_console(struct console *);
482 extern int unregister_console(struct console *);
490 extern void console_stop(struct console *);
491 extern void console_start(struct console *);
493 extern int braille_register_console(struct console *, int index,
495 extern int braille_unregister_console(struct console *);
504 /* Suspend and resume console messages over PM events */
531 /* For deferred console takeover */