NTB_TRANSPORT(4) FreeBSD Kernel Interfaces Manual NTB_TRANSPORT(4)
NAME
ntb_transport - Packet-oriented transport for Non-Transparent Bridges
SYNOPSIS
To compile this driver into your kernel, place the following lines in
your kernel configuration file:
device ntb
device ntb_transport
Or, to load the driver as a module at boot, place the following line in
loader.conf(5):
ntb_transport_load="YES"
The following tunables are settable from the loader(8):
hw.ntb_transport.debug_level
Driver debug level. The default value is 0, higher means more verbose.
hw.ntb_transport.max_mw_size
Limits maximum memory window usage. Allocation of big physically
contiguous memory buffer may be a problem, while too big buffers makes no
much sense for low latency network interface.
hint.ntb_transport.X.config
Configures a set of the transport consumers, separated by commas. Each
consumer can be configured as: "[<name>][:<queues>]", where: name is a
name of the driver to attach (empty means any), queues is a number of
queues to allocate (empty means automatic). The default configuration is
empty string, which means single consumer with one queue per memory
window, allowing any driver to attach.
hint.ntb_transport.X.compact
Non-zero value enables compact version of scratchpad protocol, using half
as many registers. Enabled automatically if there is not enough
registers to negotiate all available memory windows. The compact version
does not support memory windows of 4GB and above.
DESCRIPTION
The ntb_transport driver attaches on top of the ntb driver to utilize its
resources to create a set of bidirectional queues, delivering packets
between the systems. The primary purpose of this driver is to be used by
if_ntb network interface, but other consumers may also be developed using
KPI.
Each ntb_transport require from underlying ntb instance:
o 1 or more memory windows;
o 6 scratchpads, plus 2 more for each additional memory window, or 3
plus 1 in case of compact protocol;
o 1 doorbell for each memory window or configured queue.
SEE ALSO
if_ntb(4), ntb(4), ntb_hw_amd(4), ntb_hw_intel(4), ntb_hw_plx(4)
AUTHORS
The ntb_transport driver was developed by Intel and originally written by
Carl Delsey <
[email protected]>. Later improvements were done by Conrad
E. Meyer <
[email protected]> and Alexander Motin <
[email protected]>.
FreeBSD 14.1-RELEASE-p8 November 9, 2019 FreeBSD 14.1-RELEASE-p8