Use generic mechanism to check if UDC controller supports zlp.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Added failure check for usb_assign_descriptors call in bind function.

Acked-By: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Pavitrakumar Managutte <pavitra1729@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Removed usb_free_all_descriptors in the bind functions, which
results in double-free corruption of the descriptors on error path.
The usb descriptors are allocated by usb_assign_descriptors.

Signed-off-by: Pavitrakumar Managutte <pavitra1729@gmail.com>
Reviewed-by: Robert Baldyga <r.baldyga@samsung.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Unfortunately, the USB gadget layer has this weird things where NULL
skbs are passed into ops->ndo_start_xmit() in order to trigger the
dev->wrap() calls to build packets.

This is completely outside of the allowable range of sane arguments
for the ndo_start_xmit method.  All invocations of ndo_start_xmit()
should be with non-NULL SKB arguments.

Put back the direct call, but with a comment explaining how this
is not acceptable in the long term.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: David S. Miller <davem@davemloft.net>

The drivers/usb/gadget directory contains many files.
Files which are related can be distributed into separate directories.
This patch moves the USB functions implementations into a separate directory.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>