Messages in this thread Patch in this message | | | From | Alan Cox <> | Subject | [PATCH 01/20] tty: Introduce a tty_port common structure | Date | Mon, 19 May 2008 15:50:13 +0100 |
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From: Alan Cox <alan@redhat.com>
Every tty driver has its own concept of a port structure and because they all differ we cannot extract commonality. Begin fixing this by creating a structure drivers can elect to use so that over time we can push fields into this and create commonality and then introduce common methods. ---
drivers/char/tty_io.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/tty.h | 29 +++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+), 0 deletions(-)
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 49c1a22..fb17b18 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2004,6 +2004,43 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf, return tty_write(file, buf, count, ppos); } +void tty_port_init(struct tty_port *port) +{ + memset(port, 0, sizeof(*port)); + init_waitqueue_head(&port->open_wait); + init_waitqueue_head(&port->close_wait); + mutex_init(&port->mutex); +} + +EXPORT_SYMBOL(tty_port_init); + +int tty_port_alloc_xmit_buf(struct tty_port *port) +{ + /* We may sleep in get_zeroed_page() */ + mutex_lock(&port->mutex); + if (port->xmit_buf == NULL) + port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL); + mutex_unlock(&port->mutex); + if (port->xmit_buf == NULL) + return -ENOMEM; + return 0; +} + +EXPORT_SYMBOL(tty_port_alloc_xmit_buf); + +void tty_port_free_xmit_buf(struct tty_port *port) +{ + mutex_lock(&port->mutex); + if (port->xmit_buf != NULL) { + free_page((unsigned long)port->xmit_buf); + port->xmit_buf = NULL; + } + mutex_unlock(&port->mutex); +} + +EXPORT_SYMBOL(tty_port_free_xmit_buf); + + static char ptychar[] = "pqrstuvwxyzabcde"; /** diff --git a/include/linux/tty.h b/include/linux/tty.h index 7f7121f..a5dc3e9 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -166,6 +166,30 @@ struct tty_bufhead { struct device; struct signal_struct; + +/* + * Port level information. Each device keeps its own port level information + * so provide a common structure for those ports wanting to use common support + * routines. + * + * The tty port has a different lifetime to the tty so must be kept apart. + * In addition be careful as tty -> port mappings are valid for the life + * of the tty object but in many cases port -> tty mappings are valid only + * until a hangup so don't use the wrong path. + */ + +struct tty_port +{ + struct tty_struct *tty; /* Back pointer */ + int blocked_open; /* Waiting to open */ + int count; /* Usage count */ + wait_queue_head_t open_wait; /* Open waiters */ + wait_queue_head_t close_wait; /* Close waiters */ + unsigned long flags; /* TTY flags ASY_*/ + struct mutex mutex; /* Locking */ + unsigned char *xmit_buf; /* Optional buffer */ +}; + /* * Where all of the state associated with a tty is kept while the tty * is open. Since the termios state should be kept even if the tty @@ -241,6 +265,7 @@ struct tty_struct { spinlock_t read_lock; /* If the tty has a pending do_SAK, queue it here - akpm */ struct work_struct SAK_work; + struct tty_port *port; }; /* tty magic number */ @@ -351,6 +376,10 @@ extern void tty_write_unlock(struct tty_struct *tty); extern int tty_write_lock(struct tty_struct *tty, int ndelay); #define tty_is_writelocked(tty) (mutex_is_locked(&tty->atomic_write_lock)) +extern void tty_port_init(struct tty_port *port); +extern int tty_port_alloc_xmit_buf(struct tty_port *port); +extern void tty_port_free_xmit_buf(struct tty_port *port); + /* n_tty.c */
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