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path: root/drivers/usb/serial/opticon.c
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Diffstat (limited to 'drivers/usb/serial/opticon.c')
-rw-r--r--drivers/usb/serial/opticon.c124
1 files changed, 122 insertions, 2 deletions
diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index 00d5c60aded..8c87a49ee2b 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -1,8 +1,8 @@
/*
* Opticon USB barcode to serial driver
*
- * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
- * Copyright (C) 2008 Novell Inc.
+ * Copyright (C) 2008 - 2009 Greg Kroah-Hartman <gregkh@suse.de>
+ * Copyright (C) 2008 - 2009 Novell Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
@@ -40,8 +40,12 @@ struct opticon_private {
bool throttled;
bool actually_throttled;
bool rts;
+ int outstanding_urbs;
};
+/* max number of write urbs in flight */
+#define URB_UPPER_LIMIT 4
+
static void opticon_bulk_callback(struct urb *urb)
{
struct opticon_private *priv = urb->context;
@@ -188,6 +192,120 @@ static void opticon_close(struct tty_struct *tty, struct usb_serial_port *port,
usb_kill_urb(priv->bulk_read_urb);
}
+static void opticon_write_bulk_callback(struct urb *urb)
+{
+ struct opticon_private *priv = urb->context;
+ int status = urb->status;
+ unsigned long flags;
+
+ /* free up the transfer buffer, as usb_free_urb() does not do this */
+ kfree(urb->transfer_buffer);
+
+ if (status)
+ dbg("%s - nonzero write bulk status received: %d",
+ __func__, status);
+
+ spin_lock_irqsave(&priv->lock, flags);
+ --priv->outstanding_urbs;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ usb_serial_port_softint(priv->port);
+}
+
+static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
+ const unsigned char *buf, int count)
+{
+ struct opticon_private *priv = usb_get_serial_data(port->serial);
+ struct usb_serial *serial = port->serial;
+ struct urb *urb;
+ unsigned char *buffer;
+ unsigned long flags;
+ int status;
+
+ dbg("%s - port %d", __func__, port->number);
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->outstanding_urbs > URB_UPPER_LIMIT) {
+ spin_unlock_irqrestore(&priv->lock, flags);
+ dbg("%s - write limit hit\n", __func__);
+ return 0;
+ }
+ priv->outstanding_urbs++;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ buffer = kmalloc(count, GFP_ATOMIC);
+ if (!buffer) {
+ dev_err(&port->dev, "out of memory\n");
+ count = -ENOMEM;
+ goto error_no_buffer;
+ }
+
+ urb = usb_alloc_urb(0, GFP_ATOMIC);
+ if (!urb) {
+ dev_err(&port->dev, "no more free urbs\n");
+ count = -ENOMEM;
+ goto error_no_urb;
+ }
+
+ memcpy(buffer, buf, count);
+
+ usb_serial_debug_data(debug, &port->dev, __func__, count, buffer);
+
+ usb_fill_bulk_urb(urb, serial->dev,
+ usb_sndbulkpipe(serial->dev,
+ port->bulk_out_endpointAddress),
+ buffer, count, opticon_write_bulk_callback, priv);
+
+ /* send it down the pipe */
+ status = usb_submit_urb(urb, GFP_ATOMIC);
+ if (status) {
+ dev_err(&port->dev,
+ "%s - usb_submit_urb(write bulk) failed with status = %d\n",
+ __func__, status);
+ count = status;
+ goto error;
+ }
+
+ /* we are done with this urb, so let the host driver
+ * really free it when it is finished with it */
+ usb_free_urb(urb);
+
+ return count;
+error:
+ usb_free_urb(urb);
+error_no_urb:
+ kfree(buffer);
+error_no_buffer:
+ spin_lock_irqsave(&priv->lock, flags);
+ --priv->outstanding_urbs;
+ spin_unlock_irqrestore(&priv->lock, flags);
+ return count;
+}
+
+static int opticon_write_room(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct opticon_private *priv = usb_get_serial_data(port->serial);
+ unsigned long flags;
+
+ dbg("%s - port %d", __func__, port->number);
+
+ /*
+ * We really can take almost anything the user throws at us
+ * but let's pick a nice big number to tell the tty
+ * layer that we have lots of free space, unless we don't.
+ */
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->outstanding_urbs > URB_UPPER_LIMIT * 2 / 3) {
+ spin_unlock_irqrestore(&priv->lock, flags);
+ dbg("%s - write limit hit\n", __func__);
+ return 0;
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ return 2048;
+}
+
static void opticon_throttle(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
@@ -352,6 +470,8 @@ static struct usb_serial_driver opticon_device = {
.attach = opticon_startup,
.open = opticon_open,
.close = opticon_close,
+ .write = opticon_write,
+ .write_room = opticon_write_room,
.shutdown = opticon_shutdown,
.throttle = opticon_throttle,
.unthrottle = opticon_unthrottle,