1 files changed, 96 insertions, 0 deletions

diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
new file mode 100644
index 000000000000..553b0e9d8d17
--- /dev/null
+++ b/drivers/char/tty_port.c
@@ -0,0 +1,96 @@
+/*
+ * 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;
+        spin_unlock_irqrestore(&port->lock, flags);
+}
+EXPORT_SYMBOL(tty_port_tty_set);