usb: gadget: ncm: Add support to update wMaxSegmentSize via configfs

The max segment size is currently limited to the ethernet frame length of
the kernel which happens to be 1514 at this point in time. However the NCM
specification limits it to 64K for sixtenn bit NTB's. For peer to peer
connections, increasing the segment size gives better throughput.

Add support to configure this value before configfs symlink is created.
Also since the NTB Out/In buffer sizes are fixed at 16384 bytes, limit the
segment size to an upper cap of 8000 to allow at least a minimum of 2 MTU
sized datagrams to be aggregated.

Set the default MTU size for the ncm interface during function bind before
network interface is registered allowing MTU to be set in parity with
wMaxSegmentSize.

Update gadget documentation describing the new configfs property.

Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
Link: https://lore.kernel.org/r/20231221153216.18657-1-quic_kriskura@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: gadget: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style in
header files related to USB peripheral controller drivers.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

usb: gadget: f_ncm: Add OS descriptor support

To be able to use the default USB class drivers available in Microsoft
Windows, we need to add OS descriptors to the exported USB gadget to
tell the OS that we are compatible with the built-in drivers.

Copy the OS descriptor support from f_rndis into f_ncm. As a result,
using the WINNCM compatible ID, the UsbNcm driver is loaded on
enumeration without the need for a custom driver or inf file.

Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

usb: gadget: Change Andrzej Pietrasiewicz's e-mail address

My @samusung.com address is going to cease existing soon, so change it to
an address which can actually be used to contact me.

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

USB: gadget: function: Remove redundant license text

Now that the SPDX tag is in all USB files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Oliver Neukum <oneukum@suse.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Jerry Zhang <zhangjerry@google.com>
Cc: John Keeping <john@metanate.com>
Cc: Krzysztof Opasiak <k.opasiak@samsung.com>
Cc: Abdulhadi Mohamed <abdulahhadi2@gmail.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Janusz Dziedzic <januszx.dziedzic@linux.intel.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: add SPDX identifiers to all remaining files in drivers/usb/

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/usb/ and include/linux/usb* files with the correct
SPDX license identifier based on the license text in the file itself.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: gadget: Gadget directory cleanup - group usb functions

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>