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| Rev | Author | Line No. | Line |
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| 422 | giacomo | 1 | #ifndef _LINUX_TTY_LDISC_H |
| 2 | #define _LINUX_TTY_LDISC_H |
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| 3 | |||
| 4 | /* |
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| 5 | * This structure defines the interface between the tty line discipline |
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| 6 | * implementation and the tty routines. The following routines can be |
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| 7 | * defined; unless noted otherwise, they are optional, and can be |
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| 8 | * filled in with a null pointer. |
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| 9 | * |
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| 10 | * int (*open)(struct tty_struct *); |
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| 11 | * |
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| 12 | * This function is called when the line discipline is associated |
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| 13 | * with the tty. The line discipline can use this as an |
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| 14 | * opportunity to initialize any state needed by the ldisc routines. |
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| 15 | * |
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| 16 | * void (*close)(struct tty_struct *); |
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| 17 | * |
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| 18 | * This function is called when the line discipline is being |
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| 19 | * shutdown, either because the tty is being closed or because |
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| 20 | * the tty is being changed to use a new line discipline |
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| 21 | * |
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| 22 | * void (*flush_buffer)(struct tty_struct *tty); |
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| 23 | * |
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| 24 | * This function instructs the line discipline to clear its |
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| 25 | * buffers of any input characters it may have queued to be |
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| 26 | * delivered to the user mode process. |
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| 27 | * |
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| 28 | * ssize_t (*chars_in_buffer)(struct tty_struct *tty); |
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| 29 | * |
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| 30 | * This function returns the number of input characters the line |
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| 31 | * discipline may have queued up to be delivered to the user mode |
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| 32 | * process. |
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| 33 | * |
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| 34 | * ssize_t (*read)(struct tty_struct * tty, struct file * file, |
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| 35 | * unsigned char * buf, size_t nr); |
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| 36 | * |
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| 37 | * This function is called when the user requests to read from |
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| 38 | * the tty. The line discipline will return whatever characters |
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| 39 | * it has buffered up for the user. If this function is not |
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| 40 | * defined, the user will receive an EIO error. |
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| 41 | * |
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| 42 | * ssize_t (*write)(struct tty_struct * tty, struct file * file, |
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| 43 | * const unsigned char * buf, size_t nr); |
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| 44 | * |
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| 45 | * This function is called when the user requests to write to the |
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| 46 | * tty. The line discipline will deliver the characters to the |
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| 47 | * low-level tty device for transmission, optionally performing |
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| 48 | * some processing on the characters first. If this function is |
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| 49 | * not defined, the user will receive an EIO error. |
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| 50 | * |
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| 51 | * int (*ioctl)(struct tty_struct * tty, struct file * file, |
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| 52 | * unsigned int cmd, unsigned long arg); |
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| 53 | * |
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| 54 | * This function is called when the user requests an ioctl which |
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| 55 | * is not handled by the tty layer or the low-level tty driver. |
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| 56 | * It is intended for ioctls which affect line discpline |
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| 57 | * operation. Note that the search order for ioctls is (1) tty |
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| 58 | * layer, (2) tty low-level driver, (3) line discpline. So a |
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| 59 | * low-level driver can "grab" an ioctl request before the line |
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| 60 | * discpline has a chance to see it. |
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| 61 | * |
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| 62 | * void (*set_termios)(struct tty_struct *tty, struct termios * old); |
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| 63 | * |
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| 64 | * This function notifies the line discpline that a change has |
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| 65 | * been made to the termios structure. |
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| 66 | * |
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| 67 | * int (*poll)(struct tty_struct * tty, struct file * file, |
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| 68 | * poll_table *wait); |
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| 69 | * |
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| 70 | * This function is called when a user attempts to select/poll on a |
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| 71 | * tty device. It is solely the responsibility of the line |
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| 72 | * discipline to handle poll requests. |
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| 73 | * |
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| 74 | * void (*receive_buf)(struct tty_struct *, const unsigned char *cp, |
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| 75 | * char *fp, int count); |
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| 76 | * |
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| 77 | * This function is called by the low-level tty driver to send |
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| 78 | * characters received by the hardware to the line discpline for |
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| 79 | * processing. <cp> is a pointer to the buffer of input |
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| 80 | * character received by the device. <fp> is a pointer to a |
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| 81 | * pointer of flag bytes which indicate whether a character was |
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| 82 | * received with a parity error, etc. |
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| 83 | * |
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| 84 | * int (*receive_room)(struct tty_struct *); |
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| 85 | * |
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| 86 | * This function is called by the low-level tty driver to |
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| 87 | * determine how many characters the line discpline can accept. |
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| 88 | * The low-level driver must not send more characters than was |
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| 89 | * indicated by receive_room, or the line discpline may drop |
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| 90 | * those characters. |
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| 91 | * |
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| 92 | * void (*write_wakeup)(struct tty_struct *); |
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| 93 | * |
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| 94 | * This function is called by the low-level tty driver to signal |
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| 95 | * that line discpline should try to send more characters to the |
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| 96 | * low-level driver for transmission. If the line discpline does |
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| 97 | * not have any more data to send, it can just return. |
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| 98 | */ |
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| 99 | |||
| 100 | #include <linux/fs.h> |
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| 101 | #include <linux/wait.h> |
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| 102 | |||
| 103 | struct tty_ldisc { |
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| 104 | int magic; |
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| 105 | char *name; |
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| 106 | int num; |
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| 107 | int flags; |
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| 108 | |||
| 109 | /* |
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| 110 | * The following routines are called from above. |
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| 111 | */ |
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| 112 | int (*open)(struct tty_struct *); |
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| 113 | void (*close)(struct tty_struct *); |
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| 114 | void (*flush_buffer)(struct tty_struct *tty); |
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| 115 | ssize_t (*chars_in_buffer)(struct tty_struct *tty); |
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| 116 | ssize_t (*read)(struct tty_struct * tty, struct file * file, |
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| 117 | unsigned char * buf, size_t nr); |
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| 118 | ssize_t (*write)(struct tty_struct * tty, struct file * file, |
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| 119 | const unsigned char * buf, size_t nr); |
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| 120 | int (*ioctl)(struct tty_struct * tty, struct file * file, |
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| 121 | unsigned int cmd, unsigned long arg); |
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| 122 | void (*set_termios)(struct tty_struct *tty, struct termios * old); |
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| 123 | unsigned int (*poll)(struct tty_struct *, struct file *, |
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| 124 | struct poll_table_struct *); |
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| 125 | |||
| 126 | /* |
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| 127 | * The following routines are called from below. |
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| 128 | */ |
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| 129 | void (*receive_buf)(struct tty_struct *, const unsigned char *cp, |
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| 130 | char *fp, int count); |
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| 131 | int (*receive_room)(struct tty_struct *); |
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| 132 | void (*write_wakeup)(struct tty_struct *); |
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| 133 | |||
| 134 | struct module *owner; |
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| 135 | }; |
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| 136 | |||
| 137 | #define TTY_LDISC_MAGIC 0x5403 |
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| 138 | |||
| 139 | #define LDISC_FLAG_DEFINED 0x00000001 |
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| 140 | |||
| 141 | #define MODULE_ALIAS_LDISC(ldisc) \ |
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| 142 | MODULE_ALIAS("tty-ldisc-" __stringify(ldisc)) |
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| 143 | |||
| 144 | #endif /* _LINUX_TTY_LDISC_H */ |