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author | 2023-02-21 18:24:12 -0800 | |
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committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /drivers/misc/echo/echo.h | |
download | linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip |
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski:
"Core:
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used to
describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on
boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols:
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF:
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
better support decap on GRE tunnel devices not operating in collect
metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk and
bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols by
livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter:
- Remove the CLUSTERIP target. It has been marked as obsolete for
years, and we still have WARN splats wrt races of the out-of-band
/proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to the
existing 'delete' commands, but do not return an error if the
referenced object (set, chain, rule...) did not exist.
Driver API:
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into
multiple files, drop some of the unnecessarily granular locks and
factor out common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless
Extensions for Wi-Fi 7 devices at all. Everyone should switch to
using nl80211 interface instead.
- Improve the CAN bit timing configuration. Use extack to return
error messages directly to user space, update the SJW handling,
including the definition of a new default value that will benefit
CAN-FD controllers, by increasing their oscillator tolerance.
New hardware / drivers:
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers:
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- support XDP_REDIRECT for XDP non-linear buffers
- improve reconfig, avoid link flap and waiting for idle
- support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q,
8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation"
* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
page_pool: add a comment explaining the fragment counter usage
net: ethtool: fix __ethtool_dev_mm_supported() implementation
ethtool: pse-pd: Fix double word in comments
xsk: add linux/vmalloc.h to xsk.c
sefltests: netdevsim: wait for devlink instance after netns removal
selftest: fib_tests: Always cleanup before exit
net/mlx5e: Align IPsec ASO result memory to be as required by hardware
net/mlx5e: TC, Set CT miss to the specific ct action instance
net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
net/mlx5: Refactor tc miss handling to a single function
net/mlx5: Kconfig: Make tc offload depend on tc skb extension
net/sched: flower: Support hardware miss to tc action
net/sched: flower: Move filter handle initialization earlier
net/sched: cls_api: Support hardware miss to tc action
net/sched: Rename user cookie and act cookie
sfc: fix builds without CONFIG_RTC_LIB
sfc: clean up some inconsistent indentings
net/mlx4_en: Introduce flexible array to silence overflow warning
net: lan966x: Fix possible deadlock inside PTP
net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
...
Diffstat (limited to 'drivers/misc/echo/echo.h')
-rw-r--r-- | drivers/misc/echo/echo.h | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/misc/echo/echo.h b/drivers/misc/echo/echo.h new file mode 100644 index 000000000..56b4b95fd --- /dev/null +++ b/drivers/misc/echo/echo.h @@ -0,0 +1,175 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * SpanDSP - a series of DSP components for telephony + * + * echo.c - A line echo canceller. This code is being developed + * against and partially complies with G168. + * + * Written by Steve Underwood <steveu@coppice.org> + * and David Rowe <david_at_rowetel_dot_com> + * + * Copyright (C) 2001 Steve Underwood and 2007 David Rowe + * + * All rights reserved. + */ + +#ifndef __ECHO_H +#define __ECHO_H + +/* +Line echo cancellation for voice + +What does it do? + +This module aims to provide G.168-2002 compliant echo cancellation, to remove +electrical echoes (e.g. from 2-4 wire hybrids) from voice calls. + +How does it work? + +The heart of the echo cancellor is FIR filter. This is adapted to match the +echo impulse response of the telephone line. It must be long enough to +adequately cover the duration of that impulse response. The signal transmitted +to the telephone line is passed through the FIR filter. Once the FIR is +properly adapted, the resulting output is an estimate of the echo signal +received from the line. This is subtracted from the received signal. The result +is an estimate of the signal which originated at the far end of the line, free +from echos of our own transmitted signal. + +The least mean squares (LMS) algorithm is attributed to Widrow and Hoff, and +was introduced in 1960. It is the commonest form of filter adaption used in +things like modem line equalisers and line echo cancellers. There it works very +well. However, it only works well for signals of constant amplitude. It works +very poorly for things like speech echo cancellation, where the signal level +varies widely. This is quite easy to fix. If the signal level is normalised - +similar to applying AGC - LMS can work as well for a signal of varying +amplitude as it does for a modem signal. This normalised least mean squares +(NLMS) algorithm is the commonest one used for speech echo cancellation. Many +other algorithms exist - e.g. RLS (essentially the same as Kalman filtering), +FAP, etc. Some perform significantly better than NLMS. However, factors such +as computational complexity and patents favour the use of NLMS. + +A simple refinement to NLMS can improve its performance with speech. NLMS tends +to adapt best to the strongest parts of a signal. If the signal is white noise, +the NLMS algorithm works very well. However, speech has more low frequency than +high frequency content. Pre-whitening (i.e. filtering the signal to flatten its +spectrum) the echo signal improves the adapt rate for speech, and ensures the +final residual signal is not heavily biased towards high frequencies. A very +low complexity filter is adequate for this, so pre-whitening adds little to the +compute requirements of the echo canceller. + +An FIR filter adapted using pre-whitened NLMS performs well, provided certain +conditions are met: + + - The transmitted signal has poor self-correlation. + - There is no signal being generated within the environment being + cancelled. + +The difficulty is that neither of these can be guaranteed. + +If the adaption is performed while transmitting noise (or something fairly +noise like, such as voice) the adaption works very well. If the adaption is +performed while transmitting something highly correlative (typically narrow +band energy such as signalling tones or DTMF), the adaption can go seriously +wrong. The reason is there is only one solution for the adaption on a near +random signal - the impulse response of the line. For a repetitive signal, +there are any number of solutions which converge the adaption, and nothing +guides the adaption to choose the generalised one. Allowing an untrained +canceller to converge on this kind of narrowband energy probably a good thing, +since at least it cancels the tones. Allowing a well converged canceller to +continue converging on such energy is just a way to ruin its generalised +adaption. A narrowband detector is needed, so adapation can be suspended at +appropriate times. + +The adaption process is based on trying to eliminate the received signal. When +there is any signal from within the environment being cancelled it may upset +the adaption process. Similarly, if the signal we are transmitting is small, +noise may dominate and disturb the adaption process. If we can ensure that the +adaption is only performed when we are transmitting a significant signal level, +and the environment is not, things will be OK. Clearly, it is easy to tell when +we are sending a significant signal. Telling, if the environment is generating +a significant signal, and doing it with sufficient speed that the adaption will +not have diverged too much more we stop it, is a little harder. + +The key problem in detecting when the environment is sourcing significant +energy is that we must do this very quickly. Given a reasonably long sample of +the received signal, there are a number of strategies which may be used to +assess whether that signal contains a strong far end component. However, by the +time that assessment is complete the far end signal will have already caused +major mis-convergence in the adaption process. An assessment algorithm is +needed which produces a fairly accurate result from a very short burst of far +end energy. + +How do I use it? + +The echo cancellor processes both the transmit and receive streams sample by +sample. The processing function is not declared inline. Unfortunately, +cancellation requires many operations per sample, so the call overhead is only +a minor burden. +*/ + +#include "fir.h" +#include "oslec.h" + +/* + G.168 echo canceller descriptor. This defines the working state for a line + echo canceller. +*/ +struct oslec_state { + int16_t tx; + int16_t rx; + int16_t clean; + int16_t clean_nlp; + + int nonupdate_dwell; + int curr_pos; + int taps; + int log2taps; + int adaption_mode; + + int cond_met; + int32_t pstates; + int16_t adapt; + int32_t factor; + int16_t shift; + + /* Average levels and averaging filter states */ + int ltxacc; + int lrxacc; + int lcleanacc; + int lclean_bgacc; + int ltx; + int lrx; + int lclean; + int lclean_bg; + int lbgn; + int lbgn_acc; + int lbgn_upper; + int lbgn_upper_acc; + + /* foreground and background filter states */ + struct fir16_state_t fir_state; + struct fir16_state_t fir_state_bg; + int16_t *fir_taps16[2]; + + /* DC blocking filter states */ + int tx_1; + int tx_2; + int rx_1; + int rx_2; + + /* optional High Pass Filter states */ + int32_t xvtx[5]; + int32_t yvtx[5]; + int32_t xvrx[5]; + int32_t yvrx[5]; + + /* Parameters for the optional Hoth noise generator */ + int cng_level; + int cng_rndnum; + int cng_filter; + + /* snapshot sample of coeffs used for development */ + int16_t *snapshot; +}; + +#endif /* __ECHO_H */ |