#ifndef _LINUX_TTY_DRIVER_H
#define _LINUX_TTY_DRIVER_H
-/*
- * This structure defines the interface between the low-level tty
- * driver and the tty routines. The following routines can be
- * defined; unless noted otherwise, they are optional, and can be
- * filled in with a null pointer.
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/cdev.h>
+#include <linux/termios.h>
+#include <linux/seq_file.h>
+
+struct tty_struct;
+struct tty_driver;
+struct serial_icounter_struct;
+struct serial_struct;
+
+/**
+ * struct tty_operations -- interface between driver and tty
+ *
+ * @lookup: ``struct tty_struct *()(struct tty_driver *self, struct file *,
+ * int idx)``
*
- * struct tty_struct * (*lookup)(struct tty_driver *self, struct file *, int idx)
+ * Return the tty device corresponding to @idx, %NULL if there is not
+ * one currently in use and an %ERR_PTR value on error. Called under
+ * %tty_mutex (for now!)
*
- * Return the tty device corresponding to idx, NULL if there is not
- * one currently in use and an ERR_PTR value on error. Called under
- * tty_mutex (for now!)
+ * Optional method. Default behaviour is to use the @self->ttys array.
*
- * Optional method. Default behaviour is to use the ttys array
+ * @install: ``int ()(struct tty_driver *self, struct tty_struct *tty)``
*
- * int (*install)(struct tty_driver *self, struct tty_struct *tty)
+ * Install a new @tty into the @self's internal tables. Used in
+ * conjunction with @lookup and @remove methods.
*
- * Install a new tty into the tty driver internal tables. Used in
- * conjunction with lookup and remove methods.
+ * Optional method. Default behaviour is to use the @self->ttys array.
*
- * Optional method. Default behaviour is to use the ttys array
+ * @remove: ``void ()(struct tty_driver *self, struct tty_struct *tty)``
*
- * void (*remove)(struct tty_driver *self, struct tty_struct *tty)
+ * Remove a closed @tty from the @self's internal tables. Used in
+ * conjunction with @lookup and @remove methods.
*
- * Remove a closed tty from the tty driver internal tables. Used in
- * conjunction with lookup and remove methods.
+ * Optional method. Default behaviour is to use the @self->ttys array.
*
- * Optional method. Default behaviour is to use the ttys array
+ * @open: ``int ()(struct tty_struct *tty, struct file *)``
*
- * int (*open)(struct tty_struct * tty, struct file * filp);
+ * This routine is called when a particular @tty device is opened. This
+ * routine is mandatory; if this routine is not filled in, the attempted
+ * open will fail with %ENODEV.
*
- * This routine is called when a particular tty device is opened.
- * This routine is mandatory; if this routine is not filled in,
- * the attempted open will fail with ENODEV.
+ * Required method. Called with tty lock held. May sleep.
*
- * Required method. Called with tty lock held.
+ * @close: ``void ()(struct tty_struct *tty, struct file *)``
*
- * void (*close)(struct tty_struct * tty, struct file * filp);
+ * This routine is called when a particular @tty device is closed. At the
+ * point of return from this call the driver must make no further ldisc
+ * calls of any kind.
*
- * This routine is called when a particular tty device is closed.
- * Note: called even if the corresponding open() failed.
+ * Remark: called even if the corresponding @open() failed.
*
- * Required method. Called with tty lock held.
+ * Required method. Called with tty lock held. May sleep.
*
- * void (*shutdown)(struct tty_struct * tty);
+ * @shutdown: ``void ()(struct tty_struct *tty)``
*
- * This routine is called under the tty lock when a particular tty device
- * is closed for the last time. It executes before the tty resources
- * are freed so may execute while another function holds a tty kref.
+ * This routine is called under the tty lock when a particular @tty device
+ * is closed for the last time. It executes before the @tty resources
+ * are freed so may execute while another function holds a @tty kref.
*
- * void (*cleanup)(struct tty_struct * tty);
+ * @cleanup: ``void ()(struct tty_struct *tty)``
*
- * This routine is called asynchronously when a particular tty device
+ * This routine is called asynchronously when a particular @tty device
* is closed for the last time freeing up the resources. This is
* actually the second part of shutdown for routines that might sleep.
*
+ * @write: ``int ()(struct tty_struct *tty, const unsigned char *buf,
+ * int count)``
*
- * int (*write)(struct tty_struct * tty,
- * const unsigned char *buf, int count);
- *
- * This routine is called by the kernel to write a series of
- * characters to the tty device. The characters may come from
- * user space or kernel space. This routine will return the
+ * This routine is called by the kernel to write a series (@count) of
+ * characters (@buf) to the @tty device. The characters may come from
+ * user space or kernel space. This routine will return the
* number of characters actually accepted for writing.
*
- * Optional: Required for writable devices.
+ * May occur in parallel in special cases. Because this includes panic
+ * paths drivers generally shouldn't try and do clever locking here.
*
- * int (*put_char)(struct tty_struct *tty, unsigned char ch);
+ * Optional: Required for writable devices. May not sleep.
*
- * This routine is called by the kernel to write a single
- * character to the tty device. If the kernel uses this routine,
- * it must call the flush_chars() routine (if defined) when it is
- * done stuffing characters into the driver. If there is no room
- * in the queue, the character is ignored.
+ * @put_char: ``int ()(struct tty_struct *tty, unsigned char ch)``
*
- * Optional: Kernel will use the write method if not provided.
+ * This routine is called by the kernel to write a single character @ch to
+ * the @tty device. If the kernel uses this routine, it must call the
+ * @flush_chars() routine (if defined) when it is done stuffing characters
+ * into the driver. If there is no room in the queue, the character is
+ * ignored.
*
- * Note: Do not call this function directly, call tty_put_char
+ * Optional: Kernel will use the @write method if not provided. Do not
+ * call this function directly, call tty_put_char().
*
- * void (*flush_chars)(struct tty_struct *tty);
+ * @flush_chars: ``void ()(struct tty_struct *tty)``
*
- * This routine is called by the kernel after it has written a
- * series of characters to the tty device using put_char().
+ * This routine is called by the kernel after it has written a
+ * series of characters to the tty device using @put_char().
*
- * Optional:
+ * Optional. Do not call this function directly, call
+ * tty_driver_flush_chars().
*
- * Note: Do not call this function directly, call tty_driver_flush_chars
- *
- * unsigned int (*write_room)(struct tty_struct *tty);
+ * @write_room: ``unsigned int ()(struct tty_struct *tty)``
*
- * This routine returns the numbers of characters the tty driver
- * will accept for queuing to be written. This number is subject
- * to change as output buffers get emptied, or if the output flow
+ * This routine returns the numbers of characters the @tty driver
+ * will accept for queuing to be written. This number is subject
+ * to change as output buffers get emptied, or if the output flow
* control is acted.
*
- * Required if write method is provided else not needed.
+ * The ldisc is responsible for being intelligent about multi-threading of
+ * write_room/write calls
+ *
+ * Required if @write method is provided else not needed. Do not call this
+ * function directly, call tty_write_room()
+ *
+ * @chars_in_buffer: ``unsigned int ()(struct tty_struct *tty)``
+ *
+ * This routine returns the number of characters in the device private
+ * output queue. Used in tty_wait_until_sent() and for poll()
+ * implementation.
*
- * Note: Do not call this function directly, call tty_write_room
- *
- * int (*ioctl)(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
+ * Optional: if not provided, it is assumed there is no queue on the
+ * device. Do not call this function directly, call tty_chars_in_buffer().
*
- * This routine allows the tty driver to implement
- * device-specific ioctls. If the ioctl number passed in cmd
- * is not recognized by the driver, it should return ENOIOCTLCMD.
+ * @ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd,
+ * unsigned long arg)``
*
- * Optional
+ * This routine allows the @tty driver to implement device-specific
+ * ioctls. If the ioctl number passed in @cmd is not recognized by the
+ * driver, it should return %ENOIOCTLCMD.
*
- * long (*compat_ioctl)(struct tty_struct *tty,,
- * unsigned int cmd, unsigned long arg);
+ * Optional.
*
- * implement ioctl processing for 32 bit process on 64 bit system
+ * @compat_ioctl: ``long ()(struct tty_struct *tty, unsigned int cmd,
+ * unsigned long arg)``
*
- * Optional
- *
- * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
+ * Implement ioctl processing for 32 bit process on 64 bit system.
*
- * This routine allows the tty driver to be notified when
- * device's termios settings have changed.
+ * Optional.
*
- * Optional: Called under the termios lock
+ * @set_termios: ``void ()(struct tty_struct *tty, struct ktermios *old)``
*
+ * This routine allows the @tty driver to be notified when device's
+ * termios settings have changed. New settings are in @tty->termios.
+ * Previous settings are passed in the @old argument.
*
- * void (*set_ldisc)(struct tty_struct *tty);
+ * The API is defined such that the driver should return the actual modes
+ * selected. This means that the driver is responsible for modifying any
+ * bits in @tty->termios it cannot fulfill to indicate the actual modes
+ * being used.
*
- * This routine allows the tty driver to be notified when the
- * device's termios settings have changed.
+ * Optional. Called under the @tty->termios_rwsem. May sleep.
*
- * Optional: Called under BKL (currently)
- *
- * void (*throttle)(struct tty_struct * tty);
+ * @set_ldisc: ``void ()(struct tty_struct *tty)``
*
- * This routine notifies the tty driver that input buffers for
- * the line discipline are close to full, and it should somehow
- * signal that no more characters should be sent to the tty.
+ * This routine allows the @tty driver to be notified when the device's
+ * line discipline is being changed. At the point this is done the
+ * discipline is not yet usable.
*
- * Optional: Always invoke via tty_throttle_safe(), called under the
- * termios lock.
- *
- * void (*unthrottle)(struct tty_struct * tty);
+ * Optional. Called under the @tty->ldisc_sem and @tty->termios_rwsem.
*
- * This routine notifies the tty drivers that it should signals
- * that characters can now be sent to the tty without fear of
- * overrunning the input buffers of the line disciplines.
- *
- * Optional: Always invoke via tty_unthrottle(), called under the
- * termios lock.
+ * @throttle: ``void ()(struct tty_struct *tty)``
*
- * void (*stop)(struct tty_struct *tty);
+ * This routine notifies the @tty driver that input buffers for the line
+ * discipline are close to full, and it should somehow signal that no more
+ * characters should be sent to the @tty.
*
- * This routine notifies the tty driver that it should stop
- * outputting characters to the tty device.
+ * Serialization including with @unthrottle() is the job of the ldisc
+ * layer.
*
- * Called with ->flow.lock held. Serialized with start() method.
+ * Optional: Always invoke via tty_throttle_safe(). Called under the
+ * @tty->termios_rwsem.
*
- * Optional:
+ * @unthrottle: ``void ()(struct tty_struct *tty)``
*
- * Note: Call stop_tty not this method.
- *
- * void (*start)(struct tty_struct *tty);
+ * This routine notifies the @tty driver that it should signal that
+ * characters can now be sent to the @tty without fear of overrunning the
+ * input buffers of the line disciplines.
*
- * This routine notifies the tty driver that it resume sending
+ * Optional. Always invoke via tty_unthrottle(). Called under the
+ * @tty->termios_rwsem.
+ *
+ * @stop: ``void ()(struct tty_struct *tty)``
+ *
+ * This routine notifies the @tty driver that it should stop outputting
* characters to the tty device.
*
- * Called with ->flow.lock held. Serialized with stop() method.
+ * Called with @tty->flow.lock held. Serialized with @start() method.
+ *
+ * Optional. Always invoke via stop_tty().
+ *
+ * @start: ``void ()(struct tty_struct *tty)``
+ *
+ * This routine notifies the @tty driver that it resumed sending
+ * characters to the @tty device.
+ *
+ * Called with @tty->flow.lock held. Serialized with stop() method.
+ *
+ * Optional. Always invoke via start_tty().
+ *
+ * @hangup: ``void ()(struct tty_struct *tty)``
+ *
+ * This routine notifies the @tty driver that it should hang up the @tty
+ * device.
*
- * Optional:
+ * Optional. Called with tty lock held.
*
- * Note: Call start_tty not this method.
- *
- * void (*hangup)(struct tty_struct *tty);
+ * @break_ctl: ``int ()(struct tty_struct *tty, int state)``
*
- * This routine notifies the tty driver that it should hang up the
- * tty device.
+ * This optional routine requests the @tty driver to turn on or off BREAK
+ * status on the RS-232 port. If @state is -1, then the BREAK status
+ * should be turned on; if @state is 0, then BREAK should be turned off.
*
- * Optional:
+ * If this routine is implemented, the high-level tty driver will handle
+ * the following ioctls: %TCSBRK, %TCSBRKP, %TIOCSBRK, %TIOCCBRK.
*
- * Called with tty lock held.
+ * If the driver sets %TTY_DRIVER_HARDWARE_BREAK in tty_alloc_driver(),
+ * then the interface will also be called with actual times and the
+ * hardware is expected to do the delay work itself. 0 and -1 are still
+ * used for on/off.
*
- * int (*break_ctl)(struct tty_struct *tty, int state);
+ * Optional: Required for %TCSBRK/%BRKP/etc. handling. May sleep.
*
- * This optional routine requests the tty driver to turn on or
- * off BREAK status on the RS-232 port. If state is -1,
- * then the BREAK status should be turned on; if state is 0, then
- * BREAK should be turned off.
+ * @flush_buffer: ``void ()(struct tty_struct *tty)``
*
- * If this routine is implemented, the high-level tty driver will
- * handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
- * TIOCCBRK.
+ * This routine discards device private output buffer. Invoked on close,
+ * hangup, to implement %TCOFLUSH ioctl and similar.
*
- * If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface
- * will also be called with actual times and the hardware is expected
- * to do the delay work itself. 0 and -1 are still used for on/off.
+ * Optional: if not provided, it is assumed there is no queue on the
+ * device. Do not call this function directly, call
+ * tty_driver_flush_buffer().
*
- * Optional: Required for TCSBRK/BRKP/etc handling.
+ * @wait_until_sent: ``void ()(struct tty_struct *tty, int timeout)``
*
- * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
- *
- * This routine waits until the device has written out all of the
- * characters in its transmitter FIFO.
+ * This routine waits until the device has written out all of the
+ * characters in its transmitter FIFO. Or until @timeout (in jiffies) is
+ * reached.
*
- * Optional: If not provided the device is assumed to have no FIFO
+ * Optional: If not provided, the device is assumed to have no FIFO.
+ * Usually correct to invoke via tty_wait_until_sent(). May sleep.
*
- * Note: Usually correct to call tty_wait_until_sent
+ * @send_xchar: ``void ()(struct tty_struct *tty, char ch)``
*
- * void (*send_xchar)(struct tty_struct *tty, char ch);
+ * This routine is used to send a high-priority XON/XOFF character (@ch)
+ * to the @tty device.
*
- * This routine is used to send a high-priority XON/XOFF
- * character to the device.
+ * Optional: If not provided, then the @write method is called under
+ * the @tty->atomic_write_lock to keep it serialized with the ldisc.
*
- * Optional: If not provided then the write method is called under
- * the atomic write lock to keep it serialized with the ldisc.
+ * @tiocmget: ``int ()(struct tty_struct *tty)``
*
- * int (*resize)(struct tty_struct *tty, struct winsize *ws)
+ * This routine is used to obtain the modem status bits from the @tty
+ * driver.
*
- * Called when a termios request is issued which changes the
- * requested terminal geometry.
+ * Optional: If not provided, then %ENOTTY is returned from the %TIOCMGET
+ * ioctl. Do not call this function directly, call tty_tiocmget().
+ *
+ * @tiocmset: ``int ()(struct tty_struct *tty,
+ * unsigned int set, unsigned int clear)``
+ *
+ * This routine is used to set the modem status bits to the @tty driver.
+ * First, @clear bits should be cleared, then @set bits set.
+ *
+ * Optional: If not provided, then %ENOTTY is returned from the %TIOCMSET
+ * ioctl. Do not call this function directly, call tty_tiocmset().
+ *
+ * @resize: ``int ()(struct tty_struct *tty, struct winsize *ws)``
+ *
+ * Called when a termios request is issued which changes the requested
+ * terminal geometry to @ws.
*
* Optional: the default action is to update the termios structure
* without error. This is usually the correct behaviour. Drivers should
- * not force errors here if they are not resizable objects (eg a serial
+ * not force errors here if they are not resizable objects (e.g. a serial
* line). See tty_do_resize() if you need to wrap the standard method
- * in your own logic - the usual case.
+ * in your own logic -- the usual case.
+ *
+ * @get_icount: ``int ()(struct tty_struct *tty,
+ * struct serial_icounter *icount)``
+ *
+ * Called when the @tty device receives a %TIOCGICOUNT ioctl. Passed a
+ * kernel structure @icount to complete.
+ *
+ * Optional: called only if provided, otherwise %ENOTTY will be returned.
*
- * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
+ * @get_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
*
- * Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
- * structure to complete. This method is optional and will only be called
- * if provided (otherwise ENOTTY will be returned).
+ * Called when the @tty device receives a %TIOCGSERIAL ioctl. Passed a
+ * kernel structure @p (&struct serial_struct) to complete.
+ *
+ * Optional: called only if provided, otherwise %ENOTTY will be returned.
+ * Do not call this function directly, call tty_tiocgserial().
+ *
+ * @set_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
+ *
+ * Called when the @tty device receives a %TIOCSSERIAL ioctl. Passed a
+ * kernel structure @p (&struct serial_struct) to set the values from.
+ *
+ * Optional: called only if provided, otherwise %ENOTTY will be returned.
+ * Do not call this function directly, call tty_tiocsserial().
+ *
+ * @show_fdinfo: ``void ()(struct tty_struct *tty, struct seq_file *m)``
+ *
+ * Called when the @tty device file descriptor receives a fdinfo request
+ * from VFS (to show in /proc/<pid>/fdinfo/). @m should be filled with
+ * information.
+ *
+ * Optional: called only if provided, otherwise nothing is written to @m.
+ * Do not call this function directly, call tty_show_fdinfo().
+ *
+ * @poll_init: ``int ()(struct tty_driver *driver, int line, char *options)``
+ *
+ * kgdboc support (Documentation/dev-tools/kgdb.rst). This routine is
+ * called to initialize the HW for later use by calling @poll_get_char or
+ * @poll_put_char.
+ *
+ * Optional: called only if provided, otherwise skipped as a non-polling
+ * driver.
+ *
+ * @poll_get_char: ``int ()(struct tty_driver *driver, int line)``
+ *
+ * kgdboc support (see @poll_init). @driver should read a character from a
+ * tty identified by @line and return it.
+ *
+ * Optional: called only if @poll_init provided.
+ *
+ * @poll_put_char: ``void ()(struct tty_driver *driver, int line, char ch)``
+ *
+ * kgdboc support (see @poll_init). @driver should write character @ch to
+ * a tty identified by @line.
+ *
+ * Optional: called only if @poll_init provided.
+ *
+ * @proc_show: ``int ()(struct seq_file *m, void *driver)``
+ *
+ * Driver @driver (cast to &struct tty_driver) can show additional info in
+ * /proc/tty/driver/<driver_name>. It is enough to fill in the information
+ * into @m.
+ *
+ * Optional: called only if provided, otherwise no /proc entry created.
+ *
+ * This structure defines the interface between the low-level tty driver and
+ * the tty routines. These routines can be defined. Unless noted otherwise,
+ * they are optional, and can be filled in with a %NULL pointer.
*/
-
-#include <linux/export.h>
-#include <linux/fs.h>
-#include <linux/kref.h>
-#include <linux/list.h>
-#include <linux/cdev.h>
-#include <linux/termios.h>
-#include <linux/seq_file.h>
-
-struct tty_struct;
-struct tty_driver;
-struct serial_icounter_struct;
-struct serial_struct;
-
struct tty_operations {
struct tty_struct * (*lookup)(struct tty_driver *driver,
struct file *filp, int idx);
int (*poll_get_char)(struct tty_driver *driver, int line);
void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
#endif
- int (*proc_show)(struct seq_file *, void *);
+ int (*proc_show)(struct seq_file *m, void *driver);
} __randomize_layout;
+/**
+ * struct tty_driver -- driver for TTY devices
+ *
+ * @magic: set to %TTY_DRIVER_MAGIC in __tty_alloc_driver()
+ * @kref: reference counting. Reaching zero frees all the internals and the
+ * driver.
+ * @cdevs: allocated/registered character /dev devices
+ * @owner: modules owning this driver. Used drivers cannot be rmmod'ed.
+ * Automatically set by tty_alloc_driver().
+ * @driver_name: name of the driver used in /proc/tty
+ * @name: used for constructing /dev node name
+ * @name_base: used as a number base for constructing /dev node name
+ * @major: major /dev device number (zero for autoassignment)
+ * @minor_start: the first minor /dev device number
+ * @num: number of devices allocated
+ * @type: type of tty driver (%TTY_DRIVER_TYPE_)
+ * @subtype: subtype of tty driver (%SYSTEM_TYPE_, %PTY_TYPE_, %SERIAL_TYPE_)
+ * @init_termios: termios to set to each tty initially (e.g. %tty_std_termios)
+ * @flags: tty driver flags (%TTY_DRIVER_)
+ * @proc_entry: proc fs entry, used internally
+ * @other: driver of the linked tty; only used for the PTY driver
+ * @ttys: array of active &struct tty_struct, set by tty_standard_install()
+ * @ports: array of &struct tty_port; can be set during initialization by
+ * tty_port_link_device() and similar
+ * @termios: storage for termios at each TTY close for the next open
+ * @driver_state: pointer to driver's arbitrary data
+ * @ops: driver hooks for TTYs. Set them using tty_set_operations(). Use &struct
+ * tty_port helpers in them as much as possible.
+ * @tty_drivers: used internally to link tty_drivers together
+ *
+ * The usual handling of &struct tty_driver is to allocate it by
+ * tty_alloc_driver(), set up all the necessary members, and register it by
+ * tty_register_driver(). At last, the driver is torn down by calling
+ * tty_unregister_driver() followed by tty_driver_kref_put().
+ *
+ * The fields required to be set before calling tty_register_driver() include
+ * @driver_name, @name, @type, @subtype, @init_termios, and @ops.
+ */
struct tty_driver {
- int magic; /* magic number for this structure */
- struct kref kref; /* Reference management */
+ int magic;
+ struct kref kref;
struct cdev **cdevs;
struct module *owner;
const char *driver_name;
const char *name;
- int name_base; /* offset of printed name */
- int major; /* major device number */
- int minor_start; /* start of minor device number */
- unsigned int num; /* number of devices allocated */
- short type; /* type of tty driver */
- short subtype; /* subtype of tty driver */
- struct ktermios init_termios; /* Initial termios */
- unsigned long flags; /* tty driver flags */
- struct proc_dir_entry *proc_entry; /* /proc fs entry */
- struct tty_driver *other; /* only used for the PTY driver */
+ int name_base;
+ int major;
+ int minor_start;
+ unsigned int num;
+ short type;
+ short subtype;
+ struct ktermios init_termios;
+ unsigned long flags;
+ struct proc_dir_entry *proc_entry;
+ struct tty_driver *other;
/*
* Pointer to the tty data structures
/* tty driver magic number */
#define TTY_DRIVER_MAGIC 0x5402
-/*
- * tty driver flags
- *
- * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
- * termios setting when the last process has closed the device.
- * Used for PTY's, in particular.
- *
- * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
- * guarantee never to set any special character handling
- * flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
- * !INPCK)). That is, if there is no reason for the driver to
- * send notifications of parity and break characters up to the
- * line driver, it won't do so. This allows the line driver to
- * optimize for this case if this flag is set. (Note that there
- * is also a promise, if the above case is true, not to signal
- * overruns, either.)
- *
- * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
- * to be registered with a call to tty_register_device() when the
- * device is found in the system and unregistered with a call to
- * tty_unregister_device() so the devices will be show up
- * properly in sysfs. If not set, driver->num entries will be
- * created by the tty core in sysfs when tty_register_driver() is
- * called. This is to be used by drivers that have tty devices
- * that can appear and disappear while the main tty driver is
- * registered with the tty core.
- *
- * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
- * use dynamic memory keyed through the devpts filesystem. This
- * is only applicable to the pty driver.
- *
- * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
- * the requested timeout to the caller instead of using a simple
- * on/off interface.
- *
- * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are
- * needed per line for this driver as it would waste memory.
- * The driver will take care.
- *
- * TTY_DRIVER_UNNUMBERED_NODE -- do not create numbered /dev nodes. In
- * other words create /dev/ttyprintk and not /dev/ttyprintk0.
- * Applicable only when a driver for a single tty device is
- * being allocated.
+/**
+ * DOC: TTY Driver Flags
+ *
+ * TTY_DRIVER_RESET_TERMIOS
+ * Requests the tty layer to reset the termios setting when the last
+ * process has closed the device. Used for PTYs, in particular.
+ *
+ * TTY_DRIVER_REAL_RAW
+ * Indicates that the driver will guarantee not to set any special
+ * character handling flags if this is set for the tty:
+ *
+ * ``(IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR || !INPCK)``
+ *
+ * That is, if there is no reason for the driver to
+ * send notifications of parity and break characters up to the line
+ * driver, it won't do so. This allows the line driver to optimize for
+ * this case if this flag is set. (Note that there is also a promise, if
+ * the above case is true, not to signal overruns, either.)
+ *
+ * TTY_DRIVER_DYNAMIC_DEV
+ * The individual tty devices need to be registered with a call to
+ * tty_register_device() when the device is found in the system and
+ * unregistered with a call to tty_unregister_device() so the devices will
+ * be show up properly in sysfs. If not set, all &tty_driver.num entries
+ * will be created by the tty core in sysfs when tty_register_driver() is
+ * called. This is to be used by drivers that have tty devices that can
+ * appear and disappear while the main tty driver is registered with the
+ * tty core.
+ *
+ * TTY_DRIVER_DEVPTS_MEM
+ * Don't use the standard arrays (&tty_driver.ttys and
+ * &tty_driver.termios), instead use dynamic memory keyed through the
+ * devpts filesystem. This is only applicable to the PTY driver.
+ *
+ * TTY_DRIVER_HARDWARE_BREAK
+ * Hardware handles break signals. Pass the requested timeout to the
+ * &tty_operations.break_ctl instead of using a simple on/off interface.
+ *
+ * TTY_DRIVER_DYNAMIC_ALLOC
+ * Do not allocate structures which are needed per line for this driver
+ * (&tty_driver.ports) as it would waste memory. The driver will take
+ * care. This is only applicable to the PTY driver.
+ *
+ * TTY_DRIVER_UNNUMBERED_NODE
+ * Do not create numbered ``/dev`` nodes. For example, create
+ * ``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a
+ * driver for a single tty device is being allocated.
*/
#define TTY_DRIVER_INSTALLED 0x0001
#define TTY_DRIVER_RESET_TERMIOS 0x0002
projects / linux-2.6-microblaze.git / blobdiff