include/linux/console.h

2  *  linux/include/linux/console.h
40  * @owner:      the module to get references of when this console is used
41  * @con_startup: set up the console and return its name (like VGA, EGA, ...)
42  * @con_init:   initialize the console on @vc. @init is true for the very first
44  * @con_deinit: deinitialize the console from @vc.
52  *		Invoked by csi_M and printing to the console.
53  * @con_switch: notifier about the console switch; it is supposed to return
55  * @con_blank:  blank/unblank the console. The target mode is passed in @blank.
58  * @con_font_set: set console @vc font to @font with height @vpitch. @flags can
64  * @con_resize:	resize the @vc console to @width x @height. @from_user is true
66  * @con_set_palette: sets the palette of the console @vc to @table (optional)
67  * @con_scrolldelta: the contents of the console should be scrolled by @lines.
79  * @con_debug_enter: prepare the console for the debugger. This includes, but
80  *		is not limited to, unblanking the console, loading an
83  * @con_debug_leave: restore the console to its pre-debug state as closely as
129 extern const struct consw dummy_con;	/* dummy console buffer */
130 extern const struct consw vga_con;	/* VGA text console */
131 extern const struct consw newport_con;	/* SGI Newport console  */
153  * The interface for a console, or any other device that wants to capture
154  * console messages (printer driver?)
158  * enum cons_flags - General console flags
162  * @CON_CONSDEV:	Indicates that the console driver is backing
163  *			/dev/console.
164  * @CON_ENABLED:	Indicates if a console is allowed to print records. If
165  *			false, the console also will not advance to later
167  * @CON_BOOT:		Marks the console driver as early console driver which
170  *			when the real console driver is registered unless
173  *			that the legacy @console::write callback can be invoked
180  * @CON_EXTENDED:	The console supports the extended output format of
182  * @CON_SUSPENDED:	Indicates if a console is suspended. If true, the
200  * struct nbcon_state - console state for nbcon consoles
207  *			past. The console cannot be safe until re-initialized.
211  * state variable @console::nbcon_state.
232  * are stored in the @console::nbcon_state variable. Ensure this struct stays
239  * enum nbcon_prio - console owner priority for nbcon consoles
246  * A higher priority context can takeover the console when it is
258 struct console;
262  * struct nbcon_context - Context for console acquire/release
263  * @console:			The associated console
268  *				might cause a system freeze when the console
276 	struct console		*console;
291  * @ctxt:		The core console context
304  * struct console - The console descriptor structure
305  * @name:		The name of the console driver
307  * @read:		Read callback for console input (Optional)
309  * @unblank:		Callback to unblank the console (Optional)
310  * @setup:		Callback for initializing the console (Optional)
311  * @exit:		Callback for teardown of the console (Optional)
312  * @match:		Callback for matching a console (Optional)
321  * @node:		hlist node for the console list
328 struct console {
330 	void			(*write)(struct console *co, const char *s, unsigned int count);
331 	int			(*read)(struct console *co, char *s, unsigned int count);
332 	struct tty_driver	*(*device)(struct console *co, int *index);
334 	int			(*setup)(struct console *co, char *options);
335 	int			(*exit)(struct console *co);
336 	int			(*match)(struct console *co, char *name, int idx, char *options);
347 	/* nbcon console specific members */
348 	bool			(*write_atomic)(struct console *con,
381  * console_srcu_read_flags - Locklessly read the console flags
382  * @con:	struct console pointer of console to read flags from
385  * notation for locklessly reading the console flags. The READ_ONCE()
389  * Only use this function to read console flags when locklessly
390  * iterating the console list via srcu.
394 static inline short console_srcu_read_flags(const struct console *con)
399 	 * Locklessly reading console->flags provides a consistent
401 	 * console->flags and that CPU is using only read-modify-write
408  * console_srcu_write_flags - Write flags for a registered console
409  * @con:	struct console pointer of console to write flags to
417 static inline void console_srcu_write_flags(struct console *con, short flags)
426 static inline bool console_is_registered_locked(const struct console *con)
433  * console_is_registered - Check if the console is registered
434  * @con:	struct console pointer of console to check
436  * Context: Process context. May sleep while acquiring console list lock.
437  * Return: true if the console is in the console list, otherwise false.
439  * If false is returned for a console that was previously registered, it
440  * can be assumed that the console's unregistration is fully completed,
441  * including the exit() callback after console list removal.
443 static inline bool console_is_registered(const struct console *con)
455  * @con:	struct console pointer used as loop cursor
457  * Although SRCU guarantees the console list will be consistent, the
458  * struct console fields may be updated by other CPUs while iterating.
469  * @con:	struct console pointer used as loop cursor
471  * The console list and the &console.flags are immutable while iterating.
490 extern struct console *early_console;
498 extern void console_force_preferred_locked(struct console *con);
499 extern void register_console(struct console *);
500 extern int unregister_console(struct console *);
508 extern void console_stop(struct console *);
509 extern void console_start(struct console *);
511 extern int braille_register_console(struct console *, int index,
513 extern int braille_unregister_console(struct console *);
522 /* Suspend and resume console messages over PM events */
543 /* For deferred console takeover */