kernel/linux.git/include/linux/usb/cdc_ncm.h, branch v6.6.132

net: usb: cdc-ncm: check for filtering capability

2025-08-28T14:28:19+00:00

[ Upstream commit 61c3e8940f2d8b5bfeaeec4bedc2f3e7d873abb3 ] If the decice does not support filtering, filtering must not be used and all packets delivered for the upper layers to sort. Signed-off-by: Oliver Neukum Link: https://patch.msgid.link/20250717120649.2090929-1-oneukum@suse.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/cdc_ncm: Increase NTB max RX/TX values to 64kb

2022-07-21T11:20:28+00:00

DisplayLink ethernet devices require NTB buffers larger then 32kb in order to run with highest performance. This patch is changing upper limit of the rx and tx buffers. Those buffers are initialized with CDC_NCM_NTB_DEF_SIZE_RX and CDC_NCM_NTB_DEF_SIZE_TX which is 16kb so by default no device is affected by increased limit. Rx and tx buffer is increased under two conditions: - Device need to advertise that it supports higher buffer size in dwNtbMaxInMaxSize and dwNtbMaxOutMaxSize. - cdc_ncm/rx_max and cdc_ncm/tx_max driver parameters must be adjusted with udev rule or ethtool. Summary of testing and performance results: Tests were performed on following devices: - DisplayLink DL-3xxx family device - DisplayLink DL-6xxx family device - ASUS USB-C2500 2.5G USB3 ethernet adapter - Plugable USB3 1G USB3 ethernet adapter - EDIMAX EU-4307 USB-C ethernet adapter - Dell DBQBCBC064 USB-C ethernet adapter Performance measurements were done with: - iperf3 between two linux boxes - http://openspeedtest.com/ instance running on local test machine Insights from tests results: - All except one from third party usb adapters were not affected by increased buffer size to their advertised dwNtbOutMaxSize and dwNtbInMaxSize. Devices were generally reaching 912-940Mbps both download and upload. Only EDIMAX adapter experienced decreased download size from 929Mbps to 827Mbps with iper3, with openspeedtest decrease was from 968Mbps to 886Mbps. - DisplayLink DL-3xxx family devices experienced performance increase with iperf3 download from 300Mbps to 870Mbps and upload from 782Mbps to 844Mbps. With openspeedtest download increased from 556Mbps to 873Mbps and upload from 727Mbps to 973Mbps - DiplayLink DL-6xxx family devices are not affected by increased buffer size. Signed-off-by: Łukasz Spintzyk Acked-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20220720060518.541-2-lukasz.spintzyk@synaptics.com Signed-off-by: Paolo Abeni

net: usb: cdc_ncm: use new API for bh tasklet

2021-02-03T22:22:21+00:00

This converts the driver to use the new tasklet API introduced in commit 12cc923f1ccc ("tasklet: Introduce new initialization API") It is unfortunate that we need to add a pointer to the driver context to get back to the usbnet device, but the space will be reclaimed once there are no more users of the old API left and we can remove the data value and flag from the tasklet struct. Signed-off-by: Emil Renner Berthing Link: https://lore.kernel.org/r/20210130234637.26505-1-kernel@esmil.dk Signed-off-by: Jakub Kicinski

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

2020-03-12T05:59:31+00:00

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 Signed-off-by: David S. Miller

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

2017-11-04T10:48:02+00:00

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 Cc: Kate Stewart Cc: Philippe Ombredanne Signed-off-by: Greg Kroah-Hartman Acked-by: Felipe Balbi Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

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

2017-07-14T15:15:05+00:00

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 Reported-and-tested-by: Christian Panton Reviewed-by: Bjørn Mork CC: Bjørn Mork CC: Christian Panton CC: linux-usb@vger.kernel.org CC: netdev@vger.kernel.org CC: Oliver Neukum Signed-off-by: David S. Miller

net: cdc_ncm: Reduce memory use when kernel memory low

2017-07-03T08:50:49+00:00

The CDC-NCM driver can require large amounts of memory to create skb's and this can be a problem when the memory becomes fragmented. This especially affects embedded systems that have constrained resources but wish to maximise the throughput of CDC-NCM with 16KiB NTB's. The issue is after running for a while the kernel memory can become fragmented and it needs compacting. If the NTB allocation is needed before the memory has been compacted the atomic allocation can fail which can cause increased latency, large re-transmissions or disconnections depending upon the data being transmitted at the time. This situation occurs for less than a second until the kernel has compacted the memory but the failed devices can take a lot longer to recover from the failed TX packets. To ease this temporary situation I modified the CDC-NCM TX path to temporarily switch into a reduced memory mode which allocates an NTB that will fit into a USB_CDC_NCM_NTB_MIN_OUT_SIZE (default 2048 Bytes) sized memory block and only transmit NTB's with a single network frame until the memory situation is resolved. Each time this issue occurs we wait for an increasing number of reduced size allocations before requesting a full size one to not put additional pressure on a low memory system. Once the memory is compacted the CDC-NCM data can resume transmitting at the normal tx_max rate once again. Signed-off-by: Jim Baxter Reviewed-by: Bjørn Mork Signed-off-by: David S. Miller

NET: usb: cdc_mbim: add quirk for supporting Telit LE922A

2016-12-08T18:02:25+00:00

Telit LE922A MBIM based composition does not work properly with altsetting toggle done in cdc_ncm_bind_common. This patch adds CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE quirk to avoid this procedure that, instead, is mandatory for other modems. Signed-off-by: Daniele Palmas Reviewed-by: Bjørn Mork Signed-off-by: David S. Miller

net: cdc_ncm: avoid changing RX/TX buffers on MTU changes

2015-12-24T03:52:08+00:00

NCM buffer sizes are negotiated with the device independently of the network device MTU. The RX buffers are allocated by the usbnet framework based on the rx_urb_size value set by cdc_ncm. A single RX buffer can hold a number of MTU sized packets. The default usbnet change_mtu ndo only modifies rx_urb_size if it is equal to hard_mtu. And the cdc_ncm driver will set rx_urb_size and hard_mtu independently of each other, based on dwNtbInMaxSize and dwNtbOutMaxSize respectively. It was therefore assumed that usbnet_change_mtu() would never touch rx_urb_size. This failed to consider the case where dwNtbInMaxSize and dwNtbOutMaxSize happens to be equal. Fix by implementing an NCM specific change_mtu ndo, modifying the netdev MTU without touching the buffer size settings. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

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

2015-07-09T21:58:31+00:00

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 Signed-off-by: David S. Miller