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Diffstat (limited to 'kernel/include/linux/tty_ldisc.h')
| -rw-r--r-- | kernel/include/linux/tty_ldisc.h | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/kernel/include/linux/tty_ldisc.h b/kernel/include/linux/tty_ldisc.h new file mode 100644 index 000000000..00c9d688d --- /dev/null +++ b/kernel/include/linux/tty_ldisc.h @@ -0,0 +1,233 @@ +#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 *); + * + * 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. + * + * void (*close)(struct tty_struct *); + * + * This function is called when the line discipline is being + * shutdown, either because the tty is being closed or because + * the tty is being changed to use a new line discipline + * + * void (*flush_buffer)(struct tty_struct *tty); + * + * 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. + * + * ssize_t (*chars_in_buffer)(struct tty_struct *tty); + * + * This function returns the number of input characters the line + * discipline may have queued up to be delivered to the user mode + * process. + * + * ssize_t (*read)(struct tty_struct * tty, struct file * file, + * unsigned char * buf, size_t nr); + * + * 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. + * + * ssize_t (*write)(struct tty_struct * tty, struct file * file, + * 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. + * + * int (*ioctl)(struct tty_struct * tty, struct file * file, + * unsigned int cmd, unsigned long arg); + * + * This function is called when the user requests an ioctl which + * 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. + * + * long (*compat_ioctl)(struct tty_struct * tty, struct file * file, + * unsigned int cmd, unsigned long arg); + * + * Process ioctl calls from 32-bit process on 64-bit system + * + * void (*set_termios)(struct tty_struct *tty, struct ktermios * old); + * + * This function notifies the line discpline that a change has + * been made to the termios structure. + * + * int (*poll)(struct tty_struct * tty, struct file * file, + * poll_table *wait); + * + * 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. + * + * void (*receive_buf)(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 + * received with a parity error, etc. <fp> may be NULL to indicate + * all data received is TTY_NORMAL. + * + * void (*write_wakeup)(struct tty_struct *); + * + * 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. If the line + * discipline does have some data to send, please arise a tasklet + * or workqueue to do the real data transfer. Do not send data in + * this hook, it may leads to a deadlock. + * + * 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. + * + * void (*fasync)(struct tty_struct *, int on) + * + * Notify line discipline when signal-driven I/O is enabled or + * disabled. + * + * void (*dcd_change)(struct tty_struct *tty, unsigned int status) + * + * Tells the discipline that the DCD pin has changed its status. + * Used exclusively by the N_PPS (Pulse-Per-Second) line discipline. + * + * 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 + * received with a parity error, etc. <fp> may be NULL to indicate + * all data received is TTY_NORMAL. + * If assigned, prefer this function for automatic flow control. + */ + +#include <linux/fs.h> +#include <linux/wait.h> + + +/* + * 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 + + +struct tty_ldisc_ops { + int magic; + char *name; + int num; + int flags; + + /* + * 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); + 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, + unsigned int cmd, unsigned long arg); + long (*compat_ioctl)(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg); + void (*set_termios)(struct tty_struct *tty, struct ktermios *old); + unsigned int (*poll)(struct tty_struct *, struct file *, + struct poll_table_struct *); + int (*hangup)(struct tty_struct *tty); + + /* + * The following routines are called from below. + */ + void (*receive_buf)(struct tty_struct *, const unsigned char *cp, + char *fp, int count); + void (*write_wakeup)(struct tty_struct *); + void (*dcd_change)(struct tty_struct *, unsigned int); + void (*fasync)(struct tty_struct *tty, int on); + int (*receive_buf2)(struct tty_struct *, const unsigned char *cp, + char *fp, int count); + + struct module *owner; + + int refcount; +}; + +struct tty_ldisc { + struct tty_ldisc_ops *ops; + struct tty_struct *tty; +}; + +#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 */ |