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228 lines
8.0 KiB
228 lines
8.0 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _LINUX_TTY_LDISC_H |
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#define _LINUX_TTY_LDISC_H |
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/* |
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* This structure defines the interface between the tty line discipline |
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* implementation and the tty routines. The following routines can be |
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* defined; unless noted otherwise, they are optional, and can be |
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* filled in with a null pointer. |
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* |
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* int (*open)(struct tty_struct *); |
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* |
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* This function is called when the line discipline is associated |
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* with the tty. The line discipline can use this as an |
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* opportunity to initialize any state needed by the ldisc routines. |
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* |
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* void (*close)(struct tty_struct *); |
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* |
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* This function is called when the line discipline is being |
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* shutdown, either because the tty is being closed or because |
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* the tty is being changed to use a new line discipline |
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* |
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* void (*flush_buffer)(struct tty_struct *tty); |
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* |
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* This function instructs the line discipline to clear its |
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* buffers of any input characters it may have queued to be |
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* delivered to the user mode process. |
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* |
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* ssize_t (*read)(struct tty_struct * tty, struct file * file, |
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* unsigned char * buf, size_t nr); |
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* |
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* This function is called when the user requests to read from |
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* the tty. The line discipline will return whatever characters |
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* it has buffered up for the user. If this function is not |
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* defined, the user will receive an EIO error. |
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* |
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* ssize_t (*write)(struct tty_struct * tty, struct file * file, |
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* const unsigned char * buf, size_t nr); |
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* |
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* This function is called when the user requests to write to the |
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* tty. The line discipline will deliver the characters to the |
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* low-level tty device for transmission, optionally performing |
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* some processing on the characters first. If this function is |
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* not defined, the user will receive an EIO error. |
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* |
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* int (*ioctl)(struct tty_struct * tty, struct file * file, |
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* unsigned int cmd, unsigned long arg); |
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* |
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* This function is called when the user requests an ioctl which |
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* is not handled by the tty layer or the low-level tty driver. |
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* It is intended for ioctls which affect line discpline |
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* operation. Note that the search order for ioctls is (1) tty |
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* layer, (2) tty low-level driver, (3) line discpline. So a |
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* low-level driver can "grab" an ioctl request before the line |
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* discpline has a chance to see it. |
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* |
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* int (*compat_ioctl)(struct tty_struct * tty, struct file * file, |
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* unsigned int cmd, unsigned long arg); |
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* |
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* Process ioctl calls from 32-bit process on 64-bit system |
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* |
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* NOTE: only ioctls that are neither "pointer to compatible |
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* structure" nor tty-generic. Something private that takes |
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* an integer or a pointer to wordsize-sensitive structure |
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* belongs here, but most of ldiscs will happily leave |
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* it NULL. |
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* |
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* void (*set_termios)(struct tty_struct *tty, struct ktermios * old); |
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* |
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* This function notifies the line discpline that a change has |
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* been made to the termios structure. |
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* |
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* int (*poll)(struct tty_struct * tty, struct file * file, |
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* poll_table *wait); |
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* |
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* This function is called when a user attempts to select/poll on a |
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* tty device. It is solely the responsibility of the line |
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* discipline to handle poll requests. |
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* |
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* void (*receive_buf)(struct tty_struct *, const unsigned char *cp, |
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* char *fp, int count); |
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* |
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* This function is called by the low-level tty driver to send |
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* characters received by the hardware to the line discpline for |
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* processing. <cp> is a pointer to the buffer of input |
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* character received by the device. <fp> is a pointer to a |
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* pointer of flag bytes which indicate whether a character was |
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* received with a parity error, etc. <fp> may be NULL to indicate |
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* all data received is TTY_NORMAL. |
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* |
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* void (*write_wakeup)(struct tty_struct *); |
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* |
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* This function is called by the low-level tty driver to signal |
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* that line discpline should try to send more characters to the |
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* low-level driver for transmission. If the line discpline does |
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* not have any more data to send, it can just return. If the line |
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* discipline does have some data to send, please arise a tasklet |
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* or workqueue to do the real data transfer. Do not send data in |
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* this hook, it may leads to a deadlock. |
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* |
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* int (*hangup)(struct tty_struct *) |
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* |
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* Called on a hangup. Tells the discipline that it should |
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* cease I/O to the tty driver. Can sleep. The driver should |
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* seek to perform this action quickly but should wait until |
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* any pending driver I/O is completed. |
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* |
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* void (*dcd_change)(struct tty_struct *tty, unsigned int status) |
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* |
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* Tells the discipline that the DCD pin has changed its status. |
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* Used exclusively by the N_PPS (Pulse-Per-Second) line discipline. |
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* |
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* int (*receive_buf2)(struct tty_struct *, const unsigned char *cp, |
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* char *fp, int count); |
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* |
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* This function is called by the low-level tty driver to send |
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* characters received by the hardware to the line discpline for |
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* processing. <cp> is a pointer to the buffer of input |
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* character received by the device. <fp> is a pointer to a |
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* pointer of flag bytes which indicate whether a character was |
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* received with a parity error, etc. <fp> may be NULL to indicate |
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* all data received is TTY_NORMAL. |
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* If assigned, prefer this function for automatic flow control. |
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*/ |
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#include <linux/fs.h> |
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#include <linux/wait.h> |
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#include <linux/atomic.h> |
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/* |
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* the semaphore definition |
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*/ |
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struct ld_semaphore { |
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atomic_long_t count; |
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raw_spinlock_t wait_lock; |
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unsigned int wait_readers; |
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struct list_head read_wait; |
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struct list_head write_wait; |
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#ifdef CONFIG_DEBUG_LOCK_ALLOC |
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struct lockdep_map dep_map; |
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#endif |
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}; |
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extern void __init_ldsem(struct ld_semaphore *sem, const char *name, |
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struct lock_class_key *key); |
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#define init_ldsem(sem) \ |
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do { \ |
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static struct lock_class_key __key; \ |
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\ |
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__init_ldsem((sem), #sem, &__key); \ |
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} while (0) |
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extern int ldsem_down_read(struct ld_semaphore *sem, long timeout); |
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extern int ldsem_down_read_trylock(struct ld_semaphore *sem); |
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extern int ldsem_down_write(struct ld_semaphore *sem, long timeout); |
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extern int ldsem_down_write_trylock(struct ld_semaphore *sem); |
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extern void ldsem_up_read(struct ld_semaphore *sem); |
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extern void ldsem_up_write(struct ld_semaphore *sem); |
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#ifdef CONFIG_DEBUG_LOCK_ALLOC |
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extern int ldsem_down_read_nested(struct ld_semaphore *sem, int subclass, |
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long timeout); |
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extern int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass, |
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long timeout); |
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#else |
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# define ldsem_down_read_nested(sem, subclass, timeout) \ |
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ldsem_down_read(sem, timeout) |
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# define ldsem_down_write_nested(sem, subclass, timeout) \ |
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ldsem_down_write(sem, timeout) |
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#endif |
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struct tty_ldisc_ops { |
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int magic; |
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char *name; |
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int num; |
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int flags; |
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/* |
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* The following routines are called from above. |
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*/ |
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int (*open)(struct tty_struct *); |
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void (*close)(struct tty_struct *); |
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void (*flush_buffer)(struct tty_struct *tty); |
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ssize_t (*read)(struct tty_struct *tty, struct file *file, |
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unsigned char *buf, size_t nr, |
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void **cookie, unsigned long offset); |
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ssize_t (*write)(struct tty_struct *tty, struct file *file, |
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const unsigned char *buf, size_t nr); |
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int (*ioctl)(struct tty_struct *tty, struct file *file, |
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unsigned int cmd, unsigned long arg); |
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int (*compat_ioctl)(struct tty_struct *tty, struct file *file, |
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unsigned int cmd, unsigned long arg); |
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void (*set_termios)(struct tty_struct *tty, struct ktermios *old); |
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__poll_t (*poll)(struct tty_struct *, struct file *, |
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struct poll_table_struct *); |
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int (*hangup)(struct tty_struct *tty); |
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/* |
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* The following routines are called from below. |
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*/ |
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void (*receive_buf)(struct tty_struct *, const unsigned char *cp, |
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char *fp, int count); |
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void (*write_wakeup)(struct tty_struct *); |
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void (*dcd_change)(struct tty_struct *, unsigned int); |
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int (*receive_buf2)(struct tty_struct *, const unsigned char *cp, |
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char *fp, int count); |
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struct module *owner; |
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int refcount; |
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}; |
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struct tty_ldisc { |
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struct tty_ldisc_ops *ops; |
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struct tty_struct *tty; |
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}; |
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#define TTY_LDISC_MAGIC 0x5403 |
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#define LDISC_FLAG_DEFINED 0x00000001 |
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#define MODULE_ALIAS_LDISC(ldisc) \ |
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MODULE_ALIAS("tty-ldisc-" __stringify(ldisc)) |
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#endif /* _LINUX_TTY_LDISC_H */
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