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29 .Nd "Raspberry Pi 4 / BCM2711 Gigabit Ethernet controller driver"
31 To compile this driver into the kernel,
32 place the following lines in the
33 kernel configuration file:
34 .Bd -ragged -offset indent
41 driver supports the BCM2711 Ethernet controller
42 as found on the Raspberry Pi 4.
44 The following features are supported in the
49 .Bl -item -offset indent -compact
51 IP/TCP/UDP checksum offload for IPv4 and IPv6
53 10/100/1000Mbps operation in full-duplex mode
55 10/100Mbps operation in half-duplex mode
58 Note that the operation of transmit checksum offload is coupled
59 for IPv4 and IPv6; to disable it, both must be disabled even if both
60 address families are not in use.
64 driver supports the following media types:
65 .Bl -tag -width ".Cm 10baseT/UTP"
67 Enable autoselection of the media type and options.
68 The user can manually override
69 the autoselected mode by adding media options to
76 option can also be used to select either
82 Set 100Mbps (Fast Ethernet) operation.
86 option can also be used to select either
92 Set 1000baseT operation over twisted pair.
100 driver supports the following media options set with the
105 .Bl -tag -width ".Cm full-duplex"
107 Force full duplex operation.
109 Force half duplex operation.
112 For more information on configuring this device, see
117 driver supports the Ethernet controller portion of the Broadcom BCM2711
118 on the Raspberry Pi 4 Model B and related systems.
119 It utilizes the BCM54213PE PHY.
121 Tunables can be set at the
123 prompt before booting the kernel or stored in
125 The following loader tunable variable is available, and is also
126 available as a read-only
129 .Bl -tag -width indent
130 .It Va hw.genet.rx_batch
131 The maximum number of packets to pass to the link-layer input routine
136 The following variable is available as a
139 .Bl -tag -width indent
140 .It Va hw.genet.tx_hdr_min
141 When the driver is given an output packet in a buffer chain
142 in which the first buffer contains only the Ethernet header,
143 the number of bytes of the packet to add to the Ethernet header
145 Certain packets may be lost if this value is too small.
146 The default value is 56, and is sufficient for the observed cases to date.
151 driver has no diagnostics that are likely in normal operation.
156 most failures that cause packet loss in the transmit and receive paths
157 cause a cryptic diagnostic message naming the failure.
158 These messages generally make sense only when looking at the driver source.
170 device driver first appeared in
175 driver was written by
176 .An Mike Karels Aq Mt karels@freebsd.org .
177 Portions are derived from the bcmgenet driver in
180 and parts of the structure and common code are from the awg driver
181 for the Allwinner EMAC by Jared McNeill.