/* * Tty port functions */ #include <linux/types.h> #include <linux/errno.h> #include <linux/tty.h> #include <linux/tty_driver.h> #include <linux/tty_flip.h> #include <linux/timer.h> #include <linux/string.h> #include <linux/slab.h> #include <linux/sched.h> #include <linux/init.h> #include <linux/wait.h> #include <linux/bitops.h> #include <linux/delay.h> #include <linux/module.h> 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); spin_lock_init(&port->lock); port->close_delay = (50 * HZ) / 100; port->closing_wait = (3000 * HZ) / 100; } 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); /** * tty_port_tty_get - get a tty reference * @port: tty port * * Return a refcount protected tty instance or NULL if the port is not * associated with a tty (eg due to close or hangup) */ struct tty_struct *tty_port_tty_get(struct tty_port *port) { unsigned long flags; struct tty_struct *tty; spin_lock_irqsave(&port->lock, flags); tty = tty_kref_get(port->tty); spin_unlock_irqrestore(&port->lock, flags); return tty; } EXPORT_SYMBOL(tty_port_tty_get); /** * tty_port_tty_set - set the tty of a port * @port: tty port * @tty: the tty * * Associate the port and tty pair. Manages any internal refcounts. * Pass NULL to deassociate a port */ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty) { unsigned long flags; spin_lock_irqsave(&port->lock, flags); if (port->tty) tty_kref_put(port->tty); port->tty = tty_kref_get(tty); spin_unlock_irqrestore(&port->lock, flags); } EXPORT_SYMBOL(tty_port_tty_set);