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include/linux/tty_ldisc.h
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#ifndef _LINUX_TTY_LDISC_H #define _LINUX_TTY_LDISC_H /* * This structure defines the interface between the tty line discipline * implementation 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. * * int (*open)(struct tty_struct *); * |
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* This function is called when the line discipline is associated * with the tty. The line discipline can use this as an * opportunity to initialize any state needed by the ldisc routines. * |
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* void (*close)(struct tty_struct *); * * This function is called when the line discipline is being |
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* shutdown, either because the tty is being closed or because * the tty is being changed to use a new line discipline * |
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* void (*flush_buffer)(struct tty_struct *tty); * |
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* This function instructs the line discipline to clear its * buffers of any input characters it may have queued to be * delivered to the user mode process. * |
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* ssize_t (*chars_in_buffer)(struct tty_struct *tty); * |
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* This function returns the number of input characters the line |
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* discipline may have queued up to be delivered to the user mode * process. |
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* |
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* ssize_t (*read)(struct tty_struct * tty, struct file * file, * unsigned char * buf, size_t nr); * |
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* This function is called when the user requests to read from * the tty. The line discipline will return whatever characters * it has buffered up for the user. If this function is not * defined, the user will receive an EIO error. * |
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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); * * This function is called when the user requests to write to the * tty. The line discipline will deliver the characters to the * low-level tty device for transmission, optionally performing * some processing on the characters first. If this function is * not defined, the user will receive an EIO error. * |
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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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* * 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. * It is intended for ioctls which affect line discpline * operation. Note that the search order for ioctls is (1) tty * layer, (2) tty low-level driver, (3) line discpline. So a * low-level driver can "grab" an ioctl request before the line * discpline has a chance to see it. * |
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* long (*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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* 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 * been made to the termios structure. * |
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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 * tty device. It is solely the responsibility of the line * 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); * * This function is called by the low-level tty driver to send * characters received by the hardware to the line discpline for * processing. <cp> is a pointer to the buffer of input * character received by the device. <fp> is a pointer to a * 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 * all data received is TTY_NORMAL. |
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* |
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* void (*write_wakeup)(struct tty_struct *); * |
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* This function is called by the low-level tty driver to signal * that line discpline should try to send more characters to the * low-level driver for transmission. If the line discpline does * not have any more data to send, it can just return. |
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* * int (*hangup)(struct tty_struct *) * * Called on a hangup. Tells the discipline that it should * cease I/O to the tty driver. Can sleep. The driver should * seek to perform this action quickly but should wait until * any pending driver I/O is completed. |
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* |
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* void (*fasync)(struct tty_struct *, int on) * * Notify line discipline when signal-driven I/O is enabled or * disabled. * |
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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. * Used exclusively by the N_PPS (Pulse-Per-Second) line discipline. |
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* * int (*receive_buf2)(struct tty_struct *, const unsigned char *cp, * char *fp, int count); * * This function is called by the low-level tty driver to send * characters received by the hardware to the line discpline for * processing. <cp> is a pointer to the buffer of input * character received by the device. <fp> is a pointer to a * 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 * all data received is TTY_NORMAL. |
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* If assigned, prefer this function for automatic flow control. |
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*/ #include <linux/fs.h> #include <linux/wait.h> |
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/* * the semaphore definition */ struct ld_semaphore { long count; raw_spinlock_t wait_lock; unsigned int wait_readers; struct list_head read_wait; struct list_head write_wait; #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; #endif }; extern void __init_ldsem(struct ld_semaphore *sem, const char *name, struct lock_class_key *key); #define init_ldsem(sem) \ do { \ static struct lock_class_key __key; \ \ __init_ldsem((sem), #sem, &__key); \ } while (0) extern int ldsem_down_read(struct ld_semaphore *sem, long timeout); extern int ldsem_down_read_trylock(struct ld_semaphore *sem); extern int ldsem_down_write(struct ld_semaphore *sem, long timeout); extern int ldsem_down_write_trylock(struct ld_semaphore *sem); extern void ldsem_up_read(struct ld_semaphore *sem); extern void ldsem_up_write(struct ld_semaphore *sem); #ifdef CONFIG_DEBUG_LOCK_ALLOC extern int ldsem_down_read_nested(struct ld_semaphore *sem, int subclass, long timeout); extern int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass, long timeout); #else # define ldsem_down_read_nested(sem, subclass, timeout) \ ldsem_down_read(sem, timeout) # define ldsem_down_write_nested(sem, subclass, timeout) \ ldsem_down_write(sem, timeout) #endif |
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struct tty_ldisc_ops { |
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int magic; char *name; int num; int flags; |
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/* * The following routines are called from above. */ int (*open)(struct tty_struct *); void (*close)(struct tty_struct *); void (*flush_buffer)(struct tty_struct *tty); ssize_t (*chars_in_buffer)(struct tty_struct *tty); |
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ssize_t (*read)(struct tty_struct *tty, struct file *file, unsigned char __user *buf, size_t nr); ssize_t (*write)(struct tty_struct *tty, struct file *file, const unsigned char *buf, size_t nr); int (*ioctl)(struct tty_struct *tty, struct file *file, |
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unsigned int cmd, unsigned long arg); |
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long (*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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unsigned int (*poll)(struct tty_struct *, struct file *, struct poll_table_struct *); int (*hangup)(struct tty_struct *tty); |
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/* * The following routines are called from below. */ |
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void (*receive_buf)(struct tty_struct *, const unsigned char *cp, 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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void (*fasync)(struct tty_struct *tty, int on); |
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int (*receive_buf2)(struct tty_struct *, const unsigned char *cp, char *fp, int count); |
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struct module *owner; |
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int refcount; }; |
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struct tty_ldisc { 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 #define LDISC_FLAG_DEFINED 0x00000001 #define MODULE_ALIAS_LDISC(ldisc) \ MODULE_ALIAS("tty-ldisc-" __stringify(ldisc)) #endif /* _LINUX_TTY_LDISC_H */ |