BCE(4)

NAME
bce - Broadcom NetXtreme II PCIe Gigabit Ethernet adapter driver

SYNOPSIS
To compile this driver into the kernel, place the following lines in your kernel configuration file:

device miibus
device bce

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

    if_bce_load="YES"

DESCRIPTION
The bce driver supports Broadcom's NetXtreme II product family, including the BCM5706, BCM5708, BCM5709 and BCM5716 Ethernet controllers.

The NetXtreme II product family is composed of various Converged NIC (or CNIC) Ethernet controllers which support a TCP Offload Engine (TOE), Remote DMA (RDMA), and iSCSI acceleration, in addition to standard L2 Ethernet traffic, all on the same controller. The following features are supported in the bce driver:

TCP/UDP checksum offload
TCP segmentation offloading (TSO)
VLAN tag stripping and inserting
Interrupt coalescing
10/100/1000Mbps operation in full-duplex mode
10/100Mbps operation in half-duplex mode

The following features are supported in the bce driver for BCM5709 and BCM5716:

Receive side scaling (RSS), up to 8 reception queues
Multiple tranmission queues, up to 8 transmission queues
Multiple vector MSI-X

For BCM5709 and BCM5716, by default, the bce driver will try enabling as many reception and transmission queues as are allowed by the number of CPUs in the system. If multiple transmission queues are enabled, the round-robin arbitration is performed among the transmission queues. It should be noted that if both TSO and multiple transmission queues are enabled, the round-robin arbitration between transmission queues is done at the TSO packet boundary.

The bce driver supports the following media types:

autoselect
    Enable autoselection of the media type and options. The user can manually override the autoselected mode by adding media options to rc.conf(5).

10baseT/UTP
    Set 10Mbps operation. The ifconfig(8) mediaopt option can also be used to select either full-duplex or half-duplex modes.

100baseTX
    Set 100Mbps (Fast Ethernet) operation. The ifconfig(8) mediaopt option can also be used to select either full-duplex or half-duplex modes.

1000baseT
    Set 1000baseT operation over twisted pair. Only full-duplex mode is supported.

The bce driver supports the following media options:

full-duplex
    Force full duplex operation.

half-duplex
    Force half duplex operation.

For more information on configuring this device, see ifconfig(8). The bce driver supports polling(4).

TUNABLES
X is the device unit number.

hw.bce.tx_bds
    Maximum number of sending BDs which must be processed by the device before the device updates the status block and generates interrupt. It is used together with hw.bce.tx_ticks to achieve TX interrupt moderation. Default value is 255.

hw.bce.tx_bds_int
    Maximum number of sending BDs which must be processed by the device before the device updates the status block during host interrupt processing. Default value is 255.

hw.bce.tx_ticks
    How often status block should be updated and interrupt should be generated by the device, due to sending packets. It is used together with hw.bce.tx_bds to achieve TX interrupt moderation. Default value is 1022 (microseconds).

hw.bce.tx_ticks_int
    How often status block should be updated by the device during host interrupt processing, due to sending packets. Default value is 1022 (microseconds).

hw.bce.rx_bds
    Maximum number of BDs which must be received by the device before the device updates the status block and generates interrupt. It is used together with hw.bce.rx_ticks to achieve RX interrupt moderation. Default value is 0.

hw.bce.rx_bds_int
    Maximum number of BDs which must be received by the device before the device updates the status block during host interrupt processing. Default value is 128.

hw.bce.rx_ticks
    How often status block should be updated and interrupt should be generated by the device, due to receiving packets. It is used together with hw.bce.rx_bds to achieve RX interrupt moderation. Default value is 150 (microseconds).

hw.bce.rx_ticks_int
    How often status block should be updated by the device during host interrupt processing, due to receiving packets. Default value is 150 (microseconds).

hw.bce.msi.enable hw.bceX.msi.enable
    For BCM5706 and BCM5708, by default, the driver will use MSI if it is supported. This behavior can be turned off by setting this tunable to 0.

hw.bceX.msi.cpu
    If MSI is used, it specifies the MSI's target CPU.

hw.bce.msix.enable hw.bceX.msix.enable
    For BCM5709 and BCM5716, by default, the driver will use MSI-X if it is supported. This behavior can be turned off by setting this tunable to 0.

hw.bce.rx_pages hw.bceX.rx_pages
    How many reception descriptor pages should be used. One reception descriptor page holds 256 reception descriptors. Default value is 2.

hw.bce.tx_pages hw.bceX.tx_pages
    How many transmission descriptor pages should be used. One transmission descriptor page holds 256 transmission descriptors. Default value is 2.

hw.bce.rx_rings hw.bceX.rx_rings
    For BCM5709 and BCM5716, if MSI-X is used, this tunable specifies the number of reception queues to be enabled. Maximum allowed value for these tunables is 8. Setting these tunables to 0 allows the driver to enable as many reception queues as allowed by the number of CPUs.

hw.bce.tx_rings hw.bceX.tx_rings
    For BCM5709 and BCM5716, if MSI-X is used, this tunable specifies the number of transmission queues to be enabled. Maximum allowed value for these tunables is 8, and it must be less than or equal to the number of reception queues enabled. Setting these tunables to 0 allows the driver to enable as many transmission queues as allowed by the number of CPUs and number reception queues enabled.

hw.bce.tx_wreg
    The number of transmission descriptors should be setup before the hardware register is written. Setting this value too high will have negative effect on transmission timeliness. Setting this value too low will hurt overall transmission due to the frequent hardware register writing. Default value is 8.

MIB Variables
A number of per-interface variables are implemented in the dev.bce.X branch of the sysctl(3) MIB.

tx_bds_int
    See the tunable hw.bce.tx_bds_int.

tx_bds
    See the tunable hw.bce.tx_bds.

tx_ticks_int
    See the tunable hw.bce.tx_ticks_int.

tx_ticks
    See the tunable hw.bce.tx_ticks.

rx_bds_int
    See the tunable hw.bce.rx_bds_int.

rx_bds
    See the tunable hw.bce_rx_bds.

rx_ticks_int
    See the tunable hw.bce.rx_ticks_int.

rx_ticks
    See the tunable hw.bce.rx_ticks.

rx_rings
    Number of reception queues actually enabled (read-only). For BCM5709 and BCM5716, if MSI-X is enabled, the enabled reception queues will be one more than the value specified in the tunable hw.bce.rx_rings or hw.bceX.rx_rings. The extra reception queue is for the packets whose RSS hash could not be calculated by the hardware.

tx_rings
    Number of transmission queues enable (read-only). For BCM5709 and BCM5716, if MSI-X is enabled, use the tunable hw.bce.tx_rings or hw.bceX.tx_rings to configure it.

rx_pages
    Number of reception descriptor pages enabled (read-only). Use the tunable hw.bce.rx_pages or hw.bceX.rx_pages to configure it.

tx_pages
    Number of transmission descriptor pages enabled (read-only). Use the tunable hw.bce.tx_pages or hw.bceX.tx_pages to configure it.

tx_wreg
    See the tunable hw.bce.tx_wreg.

stat_*
    Various hardware statistics.

SEE ALSO
altq(4), arp(4), ifmedia(4), miibus(4), netintro(4), ng_ether(4), polling(4), vlan(4), ifconfig(8)

HISTORY
The bce device driver first appeared in FreeBSD 6.1.

AUTHORS
The bce driver was written by David Christensen <davidch@broadcom.com>. Sepherosa Ziehau added receive side scaling, multiple transmission queues and multiple vector MSI-X support to DragonFly.