1 files changed, 55 insertions, 0 deletions
diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
new file mode 100644
index 00000000000..6fadb19d630
--- /dev/null
+++ b/drivers/char/tty_port.c
@@ -0,0 +1,55 @@
+/*
+ * 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);
+	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);
+
+