The bge Gigabit Ethernet driver is a multi-threaded, loadable, clonable, GLD-based STREAMS driver supporting the Data Link Provider Interface, dlpi(7P), on Broadcom BCM5703C or BCM5704 Gigabit Ethernet controllers fitted to the system motherboard. These devices incorporate both MAC and PHY functions and provide three-speed (copper) Ethernet operation on the RJ-45 connectors.
The bge driver functions include controller initialization, frame transmit and receive, promiscuous and multicast support, and error recovery and reporting.
The bge driver and hardware support 'auto-negotiation,' a protocol specified by the 1000Base-T standard. Auto-negotiation allows each device to advertise its capabilities and discover those of its peer (link partner). The highest common denominator supported by both link partners is automatically selected, yielding the greatest available throughput, while requiring no manual configuration. The bge driver also allows you to configure the advertised capabilities to less than the maximum (where the full speed of the interface is not required), or to force a specific mode of operation, irrespective of the link partner's advertised capabilities.
The cloning character-special device, /dev/bge, is used to access all BCM570x devices fitted to the system motherboard.
The bge driver is dependent on /kernel/misc/gld, a loadable kernel module that provides the bge driver with the DLPI and STREAMS functionality required of a LAN driver. See gld(7D) for more details on the primitives supported by the driver.
You must send an explicit DL_ATTACH_REQ message to associate the opened stream with a particular device (PPA). The PPA ID is interpreted as an unsigned integer data type and indicates the corresponding device instance (unit) number. The driver returns an error (DL_ERROR_ACK) if the PPA field value does not correspond to a valid device instance number for the system. The device is initialized on first attach and de-initialized (stopped) at last detach.
The values returned by the driver in the DL_INFO_ACK primitive in response to a DL_INFO_REQ are:
Maximum SDU is 1500 (ETHERMTU - defined in <sys/ethernet.h>).
Minimum SDU is 0.
DLSAP address length is 8.
MAC type is DL_ETHER.
SAP length value is -2, meaning the physical address component is followed immediately by a 2-byte SAP component within the DLSAP address.
Broadcast address value is the Ethernet/IEEE broadcast address (FF:FF:FF:FF:FF:FF).
Once in the DL_ATTACHED state, you must send a DL_BIND_REQ to associate a particular Service Access Point (SAP) with the stream.
By default, the bge driver performs auto-negotiation to select the link speed and mode. Link speed and mode can be any one of the following, (as described in the IEEE803.2 standards):
1000 Mbps, full-duplex
1000 Mbps, half-duplex
100 Mbps, full-duplex
100 Mbps, half-duplex
10 Mbps, full-duplex
10 Mbps, half-duplex
The auto-negotiation protocol automatically selects:
Speed (1000 Mbps, 100 Mbps, or 10 Mbps)
Operation mode (full-duplex or half-duplex)
as the highest common denominator supported by both link partners. Because the bge device supports all modes, the effect is to select the highest throughput mode supported by the other device.
Alternatively, you can set the capabilities advertised by the bge device using ndd(1M). The driver supports a number of parameters whose names begin with adv_ (see below). Each of these parameters contains a boolean value that determines whether the device advertises that mode of operation. In addition, the adv_autoneg_cap parameter controls whether autonegotiation is performed. If adv_autoneg_cap is set to 0, the driver forces the mode of operation selected by the first non-zero parameter in priority order as listed below:
(highest priority/greatest throughput) adv_1000fdx_cap 1000Mbps full duplex adv_1000hdx_cap 1000Mpbs half duplex adv_100fdx_cap 100Mpbs full duplex adv_100hdx_cap 100Mpbs half duplex adv_10fdx_cap 10Mpbs full duplex adv_10hdx_cap 10Mpbs half duplex (lowest priority/least throughput)
For example, to prevent the device 'bge2' from advertising gigabit capabilities, enter (as super-user):
# ndd -set /dev/bge2 adv_1000hdx_cap 0 # ndd -set /dev/bge2 adv_1000fdx_cap 0
All capabilities default to enabled. Note that changing any capability parameter will cause the link to go down while the link partners renegotiate the link speed/duplex using the newly changed capabilities.
The current settings of the parameters may be found using ndd -get. In addition, the driver exports the current state, speed, and duplex setting of the link via ndd parameters (these are read only and may not be changed). For example, to check link state of device bge0:
# ndd -get /dev/bge0 link_status 1 # ndd -get /dev/bge0 link_speed 100 # ndd -get /dev/bge0 link_duplex 1
The output above indicates that the link is up and running at 100Mbps full-duplex.
Character special device
bge driver binary
bge configuration file
See attributes(5) for a description of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE|
Writing Device Drivers
STREAMS Programming Guide
Network Interfaces Programmer's Guide