tty: add kernel-doc for tty_ldisc_ops

tty_ldisc_ops structure was already partially documented in a standalone
comment in the header beginning.

Move it right before the structure and reformat it so it complies to
kernel-doc. That way, we can include it in Documentation/ later in this
series.

And add the documentation for the members where missing too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index 25f07017bbad152618d042f43e551c8ce789a8a0..e0da0ba02de9ac7972113b66377c89995b2d1e36 100644 (file)
--- a/include/linux/tty_ldisc.h
+++ b/include/linux/tty_ldisc.h
@@ -4,126 +4,6 @@
 
 struct tty_struct;
 
-/*
- * 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 (*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, 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.
- *
- * int (*compat_ioctl)(struct tty_struct *tty, unsigned int cmd,
- *                     unsigned long arg);
- *
- *     Process ioctl calls from 32-bit process on 64-bit system
- *
- *     NOTE: only ioctls that are neither "pointer to compatible
- *     structure" nor tty-generic.  Something private that takes
- *     an integer or a pointer to wordsize-sensitive structure
- *     belongs here, but most of ldiscs will happily leave
- *     it NULL.
- *
- * 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 (*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>
 #include <linux/atomic.h>
@@ -175,7 +55,128 @@ int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass,
                ldsem_down_write(sem, timeout)
 #endif
 
-
+/**
+ * struct tty_ldisc_ops - ldisc operations
+ *
+ * @name: name of this ldisc rendered in /proc/tty/ldiscs
+ * @num: ``N_*`` number (%N_TTY, %N_HDLC, ...) reserved to this ldisc
+ *
+ * @open: ``int ()(struct tty_struct *tty)``
+ *
+ *     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.
+ *
+ * @close: ``void ()(struct tty_struct *tty)``
+ *
+ *     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
+ *
+ * @flush_buffer: ``void ()(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.
+ *
+ * @read: ``ssize_t ()(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.
+ *
+ * @write: ``ssize_t ()(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.
+ *
+ * @ioctl: ``int ()(struct tty_struct *tty, 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.
+ *
+ * @compat_ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd,
+ *             unsigned long arg)``
+ *
+ *     Process ioctl calls from 32-bit process on 64-bit system.
+ *
+ *     Note that only ioctls that are neither "pointer to compatible
+ *     structure" nor tty-generic.  Something private that takes an integer or
+ *     a pointer to wordsize-sensitive structure belongs here, but most of
+ *     ldiscs will happily leave it %NULL.
+ *
+ * @set_termios: ``void ()(struct tty_struct *tty, struct ktermios *old)``
+ *
+ *     This function notifies the line discpline that a change has been made
+ *     to the termios structure.
+ *
+ * @poll: ``int ()(struct tty_struct *tty, struct file *file,
+ *               struct poll_table_struct *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.
+ *
+ * @hangup: ``void ()(struct tty_struct *tty)``
+ *
+ *     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.
+ *
+ * @receive_buf: ``void ()(struct tty_struct *tty, const unsigned char *cp,
+ *                    const 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 an array 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.
+ *
+ * @write_wakeup: ``void ()(struct tty_struct *tty)``
+ *
+ *     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 lead to a deadlock.
+ *
+ * @dcd_change: ``void ()(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.
+ *
+ * @receive_buf2: ``int ()(struct tty_struct *tty, const unsigned char *cp,
+ *                     const 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 an array 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.
+ *
+ * @owner: module containting this ldisc (for reference counting)
+ *
+ * This structure defines the interface between the tty line discipline
+ * implementation and the tty routines. The above routines can be defined.
+ * Unless noted otherwise, they are optional, and can be filled in with a %NULL
+ * pointer.
+ */
 struct tty_ldisc_ops {
        char    *name;
        int     num;
@@ -183,8 +184,8 @@ struct tty_ldisc_ops {
        /*
         * The following routines are called from above.
         */
-       int     (*open)(struct tty_struct *);
-       void    (*close)(struct tty_struct *);
+       int     (*open)(struct tty_struct *tty);
+       void    (*close)(struct tty_struct *tty);
        void    (*flush_buffer)(struct tty_struct *tty);
        ssize_t (*read)(struct tty_struct *tty, struct file *file,
                        unsigned char *buf, size_t nr,
@@ -196,18 +197,18 @@ struct tty_ldisc_ops {
        int     (*compat_ioctl)(struct tty_struct *tty, unsigned int cmd,
                        unsigned long arg);
        void    (*set_termios)(struct tty_struct *tty, struct ktermios *old);
-       __poll_t (*poll)(struct tty_struct *, struct file *,
-                            struct poll_table_struct *);
+       __poll_t (*poll)(struct tty_struct *tty, struct file *file,
+                            struct poll_table_struct *wait);
        void    (*hangup)(struct tty_struct *tty);
 
        /*
         * The following routines are called from below.
         */
-       void    (*receive_buf)(struct tty_struct *, const unsigned char *cp,
+       void    (*receive_buf)(struct tty_struct *tty, const unsigned char *cp,
                               const char *fp, int count);
-       void    (*write_wakeup)(struct tty_struct *);
-       void    (*dcd_change)(struct tty_struct *, unsigned int);
-       int     (*receive_buf2)(struct tty_struct *, const unsigned char *cp,
+       void    (*write_wakeup)(struct tty_struct *tty);
+       void    (*dcd_change)(struct tty_struct *tty, unsigned int status);
+       int     (*receive_buf2)(struct tty_struct *tty, const unsigned char *cp,
                                const char *fp, int count);
 
        struct  module *owner;