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Diffstat (limited to '')
| -rw-r--r-- | include/linux/tty_driver.h | 443 |
1 files changed, 443 insertions, 0 deletions
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h new file mode 100644 index 000000000..e10b09672 --- /dev/null +++ b/include/linux/tty_driver.h @@ -0,0 +1,443 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#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 + * + * 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(), 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. + * + * void (*set_termiox)(struct tty_struct *tty, struct termiox *new); + * + * Called when the device receives a termiox based ioctl. Passes down + * the requested data from user space. This method will not be invoked + * unless the tty also has a valid tty->termiox pointer. + * + * Optional: Called under the termios lock + * + * 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/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 tty_operations { + struct tty_struct * (*lookup)(struct tty_driver *driver, + struct file *filp, int idx); + int (*install)(struct tty_driver *driver, struct tty_struct *tty); + void (*remove)(struct tty_driver *driver, struct tty_struct *tty); + int (*open)(struct tty_struct * tty, struct file * filp); + void (*close)(struct tty_struct * tty, struct file * filp); + void (*shutdown)(struct tty_struct *tty); + void (*cleanup)(struct tty_struct *tty); + int (*write)(struct tty_struct * tty, + const unsigned char *buf, int count); + int (*put_char)(struct tty_struct *tty, unsigned char ch); + void (*flush_chars)(struct tty_struct *tty); + int (*write_room)(struct tty_struct *tty); + int (*chars_in_buffer)(struct tty_struct *tty); + int (*ioctl)(struct tty_struct *tty, + unsigned int cmd, unsigned long arg); + long (*compat_ioctl)(struct tty_struct *tty, + unsigned int cmd, unsigned long arg); + void (*set_termios)(struct tty_struct *tty, struct ktermios * old); + void (*throttle)(struct tty_struct * tty); + void (*unthrottle)(struct tty_struct * tty); + void (*stop)(struct tty_struct *tty); + void (*start)(struct tty_struct *tty); + void (*hangup)(struct tty_struct *tty); + int (*break_ctl)(struct tty_struct *tty, int state); + void (*flush_buffer)(struct tty_struct *tty); + void (*set_ldisc)(struct tty_struct *tty); + void (*wait_until_sent)(struct tty_struct *tty, int timeout); + void (*send_xchar)(struct tty_struct *tty, char ch); + int (*tiocmget)(struct tty_struct *tty); + int (*tiocmset)(struct tty_struct *tty, + unsigned int set, unsigned int clear); + int (*resize)(struct tty_struct *tty, struct winsize *ws); + int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew); + int (*get_icount)(struct tty_struct *tty, + struct serial_icounter_struct *icount); + void (*show_fdinfo)(struct tty_struct *tty, struct seq_file *m); +#ifdef CONFIG_CONSOLE_POLL + int (*poll_init)(struct tty_driver *driver, int line, char *options); + 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 *); +} __randomize_layout; + +struct tty_driver { + int magic; /* magic number for this structure */ + struct kref kref; /* Reference management */ + 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 */ + + /* + * Pointer to the tty data structures + */ + struct tty_struct **ttys; + struct tty_port **ports; + struct ktermios **termios; + void *driver_state; + + /* + * Driver methods + */ + + const struct tty_operations *ops; + struct list_head tty_drivers; +} __randomize_layout; + +extern struct list_head tty_drivers; + +extern struct tty_driver *__tty_alloc_driver(unsigned int lines, + struct module *owner, unsigned long flags); +extern void put_tty_driver(struct tty_driver *driver); +extern void tty_set_operations(struct tty_driver *driver, + const struct tty_operations *op); +extern struct tty_driver *tty_find_polling_driver(char *name, int *line); + +extern void tty_driver_kref_put(struct tty_driver *driver); + +/* Use TTY_DRIVER_* flags below */ +#define tty_alloc_driver(lines, flags) \ + __tty_alloc_driver(lines, THIS_MODULE, flags) + +/* + * DEPRECATED Do not use this in new code, use tty_alloc_driver instead. + * (And change the return value checks.) + */ +static inline struct tty_driver *alloc_tty_driver(unsigned int lines) +{ + struct tty_driver *ret = tty_alloc_driver(lines, 0); + if (IS_ERR(ret)) + return NULL; + return ret; +} + +static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) +{ + kref_get(&d->kref); + return d; +} + +/* 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 not 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. + */ +#define TTY_DRIVER_INSTALLED 0x0001 +#define TTY_DRIVER_RESET_TERMIOS 0x0002 +#define TTY_DRIVER_REAL_RAW 0x0004 +#define TTY_DRIVER_DYNAMIC_DEV 0x0008 +#define TTY_DRIVER_DEVPTS_MEM 0x0010 +#define TTY_DRIVER_HARDWARE_BREAK 0x0020 +#define TTY_DRIVER_DYNAMIC_ALLOC 0x0040 +#define TTY_DRIVER_UNNUMBERED_NODE 0x0080 + +/* tty driver types */ +#define TTY_DRIVER_TYPE_SYSTEM 0x0001 +#define TTY_DRIVER_TYPE_CONSOLE 0x0002 +#define TTY_DRIVER_TYPE_SERIAL 0x0003 +#define TTY_DRIVER_TYPE_PTY 0x0004 +#define TTY_DRIVER_TYPE_SCC 0x0005 /* scc driver */ +#define TTY_DRIVER_TYPE_SYSCONS 0x0006 + +/* system subtypes (magic, used by tty_io.c) */ +#define SYSTEM_TYPE_TTY 0x0001 +#define SYSTEM_TYPE_CONSOLE 0x0002 +#define SYSTEM_TYPE_SYSCONS 0x0003 +#define SYSTEM_TYPE_SYSPTMX 0x0004 + +/* pty subtypes (magic, used by tty_io.c) */ +#define PTY_TYPE_MASTER 0x0001 +#define PTY_TYPE_SLAVE 0x0002 + +/* serial subtype definitions */ +#define SERIAL_TYPE_NORMAL 1 + +#endif /* #ifdef _LINUX_TTY_DRIVER_H */ |