31f35939d1
This is the first step to generalising the various pieces of waiting logic duplicated in all sorts of serial drivers. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
/*
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* Tty port functions
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*/
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#include <linux/tty_flip.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/wait.h>
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#include <linux/bitops.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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void tty_port_init(struct tty_port *port)
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{
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memset(port, 0, sizeof(*port));
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init_waitqueue_head(&port->open_wait);
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init_waitqueue_head(&port->close_wait);
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mutex_init(&port->mutex);
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spin_lock_init(&port->lock);
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port->close_delay = (50 * HZ) / 100;
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port->closing_wait = (3000 * HZ) / 100;
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}
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EXPORT_SYMBOL(tty_port_init);
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int tty_port_alloc_xmit_buf(struct tty_port *port)
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{
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/* We may sleep in get_zeroed_page() */
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mutex_lock(&port->mutex);
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if (port->xmit_buf == NULL)
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port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
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mutex_unlock(&port->mutex);
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if (port->xmit_buf == NULL)
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return -ENOMEM;
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return 0;
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}
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EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
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void tty_port_free_xmit_buf(struct tty_port *port)
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{
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mutex_lock(&port->mutex);
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if (port->xmit_buf != NULL) {
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free_page((unsigned long)port->xmit_buf);
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port->xmit_buf = NULL;
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}
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mutex_unlock(&port->mutex);
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}
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EXPORT_SYMBOL(tty_port_free_xmit_buf);
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/**
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* tty_port_tty_get - get a tty reference
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* @port: tty port
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*
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* Return a refcount protected tty instance or NULL if the port is not
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* associated with a tty (eg due to close or hangup)
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*/
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struct tty_struct *tty_port_tty_get(struct tty_port *port)
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{
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unsigned long flags;
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struct tty_struct *tty;
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spin_lock_irqsave(&port->lock, flags);
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tty = tty_kref_get(port->tty);
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spin_unlock_irqrestore(&port->lock, flags);
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return tty;
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}
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EXPORT_SYMBOL(tty_port_tty_get);
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/**
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* tty_port_tty_set - set the tty of a port
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* @port: tty port
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* @tty: the tty
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*
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* Associate the port and tty pair. Manages any internal refcounts.
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* Pass NULL to deassociate a port
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*/
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void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
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{
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unsigned long flags;
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spin_lock_irqsave(&port->lock, flags);
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if (port->tty)
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tty_kref_put(port->tty);
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port->tty = tty_kref_get(tty);
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spin_unlock_irqrestore(&port->lock, flags);
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}
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EXPORT_SYMBOL(tty_port_tty_set);
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/**
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* tty_port_carrier_raised - carrier raised check
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* @port: tty port
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*
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* Wrapper for the carrier detect logic. For the moment this is used
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* to hide some internal details. This will eventually become entirely
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* internal to the tty port.
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*/
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int tty_port_carrier_raised(struct tty_port *port)
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{
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if (port->ops->carrier_raised == NULL)
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return 1;
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return port->ops->carrier_raised(port);
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}
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EXPORT_SYMBOL(tty_port_carrier_raised);
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