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authorJohan Hovold <jhovold@gmail.com>2010-05-05 23:58:13 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2010-05-20 13:21:42 -0700
commitc23e5fc1f7dba228558b4a46e68f7af89515b13c (patch)
treeadd71b10dc2275c98d3439fe3756829c2ec0afc9 /drivers/usb/serial/ftdi_sio.c
parent27c7acf22047fbe4ec4cc36b7c2610dba227697c (diff)
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USB: serial: remove multi-urb write from generic driver
Remove multi-urb write from the generic driver and simplify the prepare_write_buffer prototype: int (*prepare_write_buffer)(struct usb_serial_port *port, void *dest, size_t size); The default implementation simply fills dest with data from port write fifo but drivers can override it if they need to process the outgoing data (e.g. add headers). Turn ftdi_sio into a generic fifo-based driver, which lowers CPU usage significantly for small writes while retaining maximum throughput. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/serial/ftdi_sio.c')
-rw-r--r--drivers/usb/serial/ftdi_sio.c59
1 files changed, 21 insertions, 38 deletions
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index f515f32cde6..14f7a34d614 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -781,7 +781,7 @@ static void ftdi_close(struct usb_serial_port *port);
static void ftdi_dtr_rts(struct usb_serial_port *port, int on);
static void ftdi_process_read_urb(struct urb *urb);
static int ftdi_prepare_write_buffer(struct usb_serial_port *port,
- void **dest, size_t size, const void *buf, size_t count);
+ void *dest, size_t size);
static void ftdi_set_termios(struct tty_struct *tty,
struct usb_serial_port *port, struct ktermios *old);
static int ftdi_tiocmget(struct tty_struct *tty, struct file *file);
@@ -808,8 +808,7 @@ static struct usb_serial_driver ftdi_sio_device = {
.id_table = id_table_combined,
.num_ports = 1,
.bulk_in_size = 512,
- /* Must modify prepare_write_buffer if multi_urb_write is changed. */
- .multi_urb_write = 1,
+ .bulk_out_size = 256,
.probe = ftdi_sio_probe,
.port_probe = ftdi_sio_port_probe,
.port_remove = ftdi_sio_port_remove,
@@ -1531,15 +1530,6 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port)
quirk->port_probe(priv);
priv->port = port;
-
- /* Free port's existing write urb and transfer buffer. */
- if (port->write_urb) {
- usb_free_urb(port->write_urb);
- port->write_urb = NULL;
- }
- kfree(port->bulk_out_buffer);
- port->bulk_out_buffer = NULL;
-
usb_set_serial_port_data(port, priv);
ftdi_determine_type(port);
@@ -1734,8 +1724,7 @@ static void ftdi_close(struct usb_serial_port *port)
dbg("%s", __func__);
- /* shutdown our bulk read */
- usb_kill_urb(port->read_urb);
+ usb_serial_generic_close(port);
kref_put(&priv->kref, ftdi_sio_priv_release);
}
@@ -1747,40 +1736,34 @@ static void ftdi_close(struct usb_serial_port *port)
* The new devices do not require this byte
*/
static int ftdi_prepare_write_buffer(struct usb_serial_port *port,
- void **dest, size_t size, const void *src, size_t count)
+ void *dest, size_t size)
{
struct ftdi_private *priv;
- unsigned char *buffer;
- int len;
+ int count;
+ unsigned long flags;
priv = usb_get_serial_port_data(port);
- len = count;
- if (priv->chip_type == SIO && count != 0)
- len += ((count - 1) / (priv->max_packet_size - 1)) + 1;
-
- buffer = kmalloc(len, GFP_ATOMIC);
- if (!buffer) {
- dev_err(&port->dev, "%s - could not allocate buffer\n",
- __func__);
- return -ENOMEM;
- }
-
if (priv->chip_type == SIO) {
- int i, msg_len;
-
- for (i = 0; i < len; i += priv->max_packet_size) {
- msg_len = min_t(int, len - i, priv->max_packet_size) - 1;
- buffer[i] = (msg_len << 2) + 1;
- memcpy(&buffer[i + 1], src, msg_len);
- src += msg_len;
+ unsigned char *buffer = dest;
+ int i, len, c;
+
+ count = 0;
+ spin_lock_irqsave(&port->lock, flags);
+ for (i = 0; i < size - 1; i += priv->max_packet_size) {
+ len = min_t(int, size - i, priv->max_packet_size) - 1;
+ buffer[i] = (len << 2) + 1;
+ c = kfifo_out(&port->write_fifo, &buffer[i + 1], len);
+ if (!c)
+ break;
+ count += c + 1;
}
+ spin_unlock_irqrestore(&port->lock, flags);
} else {
- memcpy(buffer, src, count);
+ count = kfifo_out_locked(&port->write_fifo, dest, size,
+ &port->lock);
}
- *dest = buffer;
-
return count;
}