mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-10-28 07:13:34 +00:00
Code Issues Releases Wiki Activity

tty: add kernel-doc for tty_operations

Browse source 
tty_operations structure was already documented in a standalone comment
in the header beginning.

Move it right before the structure and reformat it so it complies to
kernel-doc. That way, we can include it in Documentation/ later in this
series.

Note that we named proc_show's parameters, so that we can reference
them in the text.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2021-11-26 09:15:52 +01:00 committed by Greg Kroah-Hartman
parent a656383021
commit 1fe1830917
1 changed files with 314 additions and 230 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

544
include/linux/tty_driver.h
View file

@ -2,235 +2,6 @@
#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.
*
* 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!)
*
* Optional method. Default behaviour is to use the ttys array
*
* int (*install)(struct tty_driver *self, struct tty_struct *tty)
*
* 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 ttys array
*
* void (*remove)(struct tty_driver *self, struct tty_struct *tty)
*
* 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 ttys array
*
* 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.
*
* Required method. Called with tty lock held.
*
* void (*close)(struct tty_struct * tty, struct file * filp);
*
* This routine is called when a particular tty device is closed.
* Note: called even if the corresponding open() failed.
*
* Required method. Called with tty lock held.
*
* void (*shutdown)(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.
*
* void (*cleanup)(struct tty_struct * tty);
*
* 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.
*
*
* 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
* number of characters actually accepted for writing.
*
* Optional: Required for writable devices.
*
* int (*put_char)(struct tty_struct *tty, unsigned char ch);
*
* 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.
*
* Optional: Kernel will use the write method if not provided.
*
* Note: Do not call this function directly, call tty_put_char
*
* void (*flush_chars)(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().
*
* Optional:
*
* Note: Do not call this function directly, call tty_driver_flush_chars
*
* unsigned int (*write_room)(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
* control is acted.
*
* Required if write method is provided else not needed.
*
* Note: Do not call this function directly, call tty_write_room
*
* int (*ioctl)(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
*
* 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.
*
* Optional
*
* long (*compat_ioctl)(struct tty_struct *tty,,
* unsigned int cmd, unsigned long arg);
*
* implement ioctl processing for 32 bit process on 64 bit system
*
* Optional
*
* void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
*
* This routine allows the tty driver to be notified when
* device's termios settings have changed.
*
* Optional: Called under the termios lock
*
*
* void (*set_ldisc)(struct tty_struct *tty);
*
* This routine allows the tty driver to be notified when the
* device's termios settings have changed.
*
* Optional: Called under BKL (currently)
*
* void (*throttle)(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.
*
* Optional: Always invoke via tty_throttle_safe(), called under the
* termios lock.
*
* void (*unthrottle)(struct tty_struct * tty);
*
* 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.
*
* void (*stop)(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 start() method.
*
* Optional:
*
* Note: Call stop_tty not this method.
*
* void (*start)(struct tty_struct *tty);
*
* This routine notifies the tty driver that it resume sending
* characters to the tty device.
*
* Called with ->flow.lock held. Serialized with stop() method.
*
* Optional:
*
* Note: Call start_tty not this method.
*
* void (*hangup)(struct tty_struct *tty);
*
* This routine notifies the tty driver that it should hang up the
* tty device.
*
* Optional:
*
* Called with tty lock held.
*
* int (*break_ctl)(struct tty_struct *tty, int state);
*
* 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.
*
* If this routine is implemented, the high-level tty driver will
* handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
* TIOCCBRK.
*
* 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: Required for TCSBRK/BRKP/etc handling.
*
* 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.
*
* Optional: If not provided the device is assumed to have no FIFO
*
* Note: Usually correct to call tty_wait_until_sent
*
* void (*send_xchar)(struct tty_struct *tty, char ch);
*
* 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 atomic write lock to keep it serialized with the ldisc.
*
* int (*resize)(struct tty_struct *tty, struct winsize *ws)
*
* Called when a termios request is issued which changes the
* requested terminal geometry.
*
* 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
* line). See tty_do_resize() if you need to wrap the standard method
* in your own logic - the usual case.
*
* int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
*
* 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).
*/
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/kref.h>
@ -244,6 +15,319 @@ 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)``
*
* 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.
*
* @install: ``int ()(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.
*
* Optional method. Default behaviour is to use the @self->ttys array.
*
* @remove: ``void ()(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.
*
* Optional method. Default behaviour is to use the @self->ttys array.
*
* @open: ``int ()(struct tty_struct *tty, struct file *)``
*
* 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.
*
* @close: ``void ()(struct tty_struct *tty, struct file *)``
*
* This routine is called when a particular @tty device is closed.
*
* Remark: called even if the corresponding @open() failed.
*
* Required method. Called with tty lock held.
*
* @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.
*
* @cleanup: ``void ()(struct tty_struct *tty)``
*
* 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)``
*
* 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.
*
* @put_char: ``int ()(struct tty_struct *tty, unsigned char ch)``
*
* 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.
*
* Optional: Kernel will use the @write method if not provided. Do not
* call this function directly, call tty_put_char().
*
* @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().
*
* Optional. Do not call this function directly, call
* tty_driver_flush_chars().
*
* @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
* control is acted.
*
* 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.
*
* 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().
*
* @ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd,
* unsigned long arg)``
*
* 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.
*
* Optional.
*
* @compat_ioctl: ``long ()(struct tty_struct *tty, unsigned int cmd,
* unsigned long arg)``
*
* Implement ioctl processing for 32 bit process on 64 bit system.
*
* Optional.
*
* @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.
*
* Optional: Called under the @tty->termios_rwsem.
*
* @set_ldisc: ``void ()(struct tty_struct *tty)``
*
* This routine allows the @tty driver to be notified when the device's
* line discipline is being changed.
*
* Optional. Called under the @tty->ldisc_sem and @tty->termios_rwsem.
*
* @throttle: ``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.
*
* Optional: Always invoke via tty_throttle_safe(). Called under the
* @tty->termios_rwsem.
*
* @unthrottle: ``void ()(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.
*
* 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 @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. Called with tty lock held.
*
* @break_ctl: ``int ()(struct tty_struct *tty, int state)``
*
* 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.
*
* If this routine is implemented, the high-level tty driver will handle
* the following ioctls: %TCSBRK, %TCSBRKP, %TIOCSBRK, %TIOCCBRK.
*
* 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.
*
* Optional: Required for %TCSBRK/%BRKP/etc. handling.
*
* @flush_buffer: ``void ()(struct tty_struct *tty)``
*
* This routine discards device private output buffer. Invoked on close,
* hangup, to implement %TCOFLUSH ioctl and similar.
*
* 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().
*
* @wait_until_sent: ``void ()(struct tty_struct *tty, int timeout)``
*
* 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.
* Usually correct to invoke via tty_wait_until_sent().
*
* @send_xchar: ``void ()(struct tty_struct *tty, char ch)``
*
* This routine is used to send a high-priority XON/XOFF character (@ch)
* to the @tty device.
*
* Optional: If not provided, then the @write method is called under
* the @tty->atomic_write_lock to keep it serialized with the ldisc.
*
* @tiocmget: ``int ()(struct tty_struct *tty)``
*
* This routine is used to obtain the modem status bits from the @tty
* driver.
*
* 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 (e.g. a serial
* line). See tty_do_resize() if you need to wrap the standard method
* 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.
*
* @get_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
*
* 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.
*/
struct tty_operations {
struct tty_struct * (*lookup)(struct tty_driver *driver,
struct file *filp, int idx);
@ -288,7 +372,7 @@ struct tty_operations {
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;
/**