diff options
Diffstat (limited to 'drivers/usb/serial/opticon.c')
| -rw-r--r-- | drivers/usb/serial/opticon.c | 124 |
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, |