usb: class: cdc-wdm: WWAN framework integration

The WWAN framework provides a unified way to handle WWAN/modems and its
control port(s). It has initially been introduced to support MHI/PCI
modems, offering the same control protocols as the USB variants such as
MBIM, QMI, AT... The WWAN framework exposes these control protocols as
character devices, similarly to cdc-wdm, but in a bus agnostic fashion.

This change adds registration of the USB modem cdc-wdm control endpoints
to the WWAN framework as standard control ports (wwanXpY...).

Exposing cdc-wdm through WWAN framework normally maintains backward
compatibility, e.g:
$ qmicli --device-open-qmi -d /dev/wwan0p1QMI --dms-get-ids
instead of
$ qmicli --device-open-qmi -d /dev/cdc-wdm0 --dms-get-ids

However, some tools may rely on cdc-wdm driver/device name for device
detection. It is then safer to keep the 'legacy' cdc-wdm character
device to prevent any breakage. This is handled in this change by
API mutual exclusion, only one access method can be used at a time,
either cdc-wdm chardev or WWAN API.

Note that unknown channel types (other than MBIM, AT or MBIM) are not
registered to the WWAN framework.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: huawei_cdc_ncm: remove redundant assignment to variable ret

The variable ret is being initializeed with a value that is never read
and it is being updated later with a new value. The initialization
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

cdc_ncm: Implement the 32-bit version of NCM Transfer Block

The NCM specification defines two formats of transfer blocks: with 16-bit
fields (NTB-16) and with 32-bit fields (NTB-32). Currently only NTB-16 is
implemented.

This patch adds the support of NTB-32. The motivation behind this is that
some devices such as E5785 or E5885 from the current generation of Huawei
LTE routers do not support NTB-16. The previous generations of Huawei
devices are also use NTB-32 by default.

Also this patch enables NTB-32 by default for Huawei devices.

During the 2019 ValdikSS made five attempts to contact Huawei to add the
NTB-16 support to their router firmware, but they were unsuccessful.

Signed-off-by: Alexander Bersenev <bay@hackerdom.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

cdc_ncm: Set NTB format again after altsetting switch for Huawei devices

Some firmwares in Huawei E3372H devices have been observed to switch back
to NTB 32-bit format after altsetting switch.
This patch implements a driver flag to check for the device settings and
set NTB format to 16-bit again if needed.
The flag has been activated for devices controlled by the huawei_cdc_ncm.c
driver.

V1->V2:
- fixed broken error checks
- some corrections to the commit message
V2->V3:
- variable name changes, to clarify what's happening
- check (and possibly set) the NTB format later in the common bind code path

Signed-off-by: Enrico Mioso <mrkiko.rs@gmail.com>
Reported-and-tested-by: Christian Panton <christian@panton.org>
Reviewed-by: Bjørn Mork <bjorn@mork.no>
CC: Bjørn Mork <bjorn@mork.no>
CC: Christian Panton <christian@panton.org>
CC: linux-usb@vger.kernel.org
CC: netdev@vger.kernel.org
CC: Oliver Neukum <oliver@neukum.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

cdc_ncm: Add support for moving NDP to end of NCM frame

NCM specs are not actually mandating a specific position in the frame for
the NDP (Network Datagram Pointer). However, some Huawei devices will
ignore our aggregates if it is not placed after the datagrams it points
to. Add support for doing just this, in a per-device configurable way.
While at it, update NCM subdrivers, disabling this functionality in all of
them, except in huawei_cdc_ncm where it is enabled instead.
We aren't making any distinction between different Huawei NCM devices,
based on what the vendor driver does. Standard NCM devices are left
unaffected: if they are compliant, they should be always usable, still
stay on the safe side.

This change has been tested and working with a Huawei E3131 device (which
works regardless of NDP position), a Huawei E3531 (also working both
ways) and an E3372 (which mandates NDP to be after indexed datagrams).

V1->V2:
- corrected wrong NDP acronym definition
- fixed possible NULL pointer dereference
- patch cleanup
V2->V3:
- Properly account for the NDP size when writing new packets to SKB

Signed-off-by: Enrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: huawei_cdc_ncm: add "subclass 3" devices

Huawei's usage of the subclass and protocol fields is not 100%
clear to us, but there appears to be a very strict system.

A device with the "shared" device ID 12d1:1506 and this NCM
function was recently reported (showing only default altsetting):

Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 3
bInterfaceProtocol 22
iInterface 8 CDC Network Control Model (NCM)
** UNRECOGNIZED: 05 24 00 10 01
** UNRECOGNIZED: 06 24 1a 00 01 1f
** UNRECOGNIZED: 0c 24 1b 00 01 00 04 10 14 dc 05 20
** UNRECOGNIZED: 0d 24 0f 0a 0f 00 00 00 ea 05 03 00 01
** UNRECOGNIZED: 05 24 06 01 01
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x85 EP 5 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0010 1x 16 bytes
bInterval 9

Cc: Enrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: huawei_cdc_ncm: increase command buffer size

Messages from the modem exceeding 256 bytes cause communication
failure.

The WDM protocol is strictly "read on demand", meaning that we only
poll for unread data after receiving a notification from the modem.
Since we have no way to know how much data the modem has to send,
we must make sure that the buffer we provide is "big enough".
Message truncation does not work. Truncated messages are left unread
until the modem has another message to send. Which often won't
happen until the userspace application has given up waiting for the
final part of the last message, and therefore sends another command.

With a proper CDC WDM function there is a descriptor telling us
which buffer size the modem uses. But with this vendor specific
implementation there is no known way to calculate the exact "big
enough" number. It is an unknown property of the modem firmware.
Experience has shown that 256 is too small. The discussion of
this failure ended up concluding that 512 might be too small as
well. So 1024 seems like a reasonable value for now.

Fixes: 41c47d8cfd68 ("net: huawei_cdc_ncm: Introduce the huawei_cdc_ncm driver")
Cc: Enrico Mioso <mrkiko.rs@gmail.com>
Reported-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-By: Enrico Mioso <mrkiko.rs@gmail.com>
Tested-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: cdc_ncm: remove redundant "disconnected" flag

Calling netif_carrier_{on,off} is sufficient. There is no need
to duplicate the carrier state in a driver specific flag.

Acked-by: Enrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: huawei_cdc_ncm: Introduce the huawei_cdc_ncm driver

This driver supports devices using the NCM protocol as an encapsulation layer
for other protocols, like the E3131 Huawei 3G modem. This drivers approach was
heavily inspired by the qmi_wwan/cdc_mbim approach & code model.

Signed-off-by: Enrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>