tree a55b216df6a5977ab8d502df44397ef7ebbb11bc
parent 25d514ca227e1ac81d0906a4ccf2aa171f50a600
author Johan Hovold <jhovold@gmail.com> 1268863568 +0100
committer Greg Kroah-Hartman <gregkh@suse.de> 1274386895 -0700

USB: serial: generalise write buffer preparation

Generalise write buffer preparation.

This allows for drivers to manipulate (e.g. add headers) to bulk out
data before it is sent.

This adds a new function pointer to usb_serial_driver:

int (*prepare_write_buffer)(struct usb_serial_port *port,
		void **dest, size_t size, const void *src, size_t count);

The function is generic and can be used with either kfifo-based or
multi-urb writes:

If *dest is NULL the implementation should allocate dest.
If src is NULL the implementation should use the port write fifo.

If not set, a generic implementation is used which simply uses memcpy or
kfifo_out.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>