64 lines
2.5 KiB
ReStructuredText
64 lines
2.5 KiB
ReStructuredText
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.. SPDX-License-Identifier: GPL-2.0
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=====================================================
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Notes on the DEC FDDIcontroller 700 (DEFZA-xx) driver
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=====================================================
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:Version: v.1.1.4
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DEC FDDIcontroller 700 is DEC's first-generation TURBOchannel FDDI
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network card, designed in 1990 specifically for the DECstation 5000
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model 200 workstation. The board is a single attachment station and
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it was manufactured in two variations, both of which are supported.
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First is the SAS MMF DEFZA-AA option, the original design implementing
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the standard MMF-PMD, however with a pair of ST connectors rather than
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the usual MIC connector. The other one is the SAS ThinWire/STP DEFZA-CA
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option, denoted 700-C, with the network medium selectable by a switch
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between the DEC proprietary ThinWire-PMD using a BNC connector and the
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standard STP-PMD using a DE-9F connector. This option can interface to
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a DECconcentrator 500 device and, in the case of the STP-PMD, also other
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FDDI equipment and was designed to make it easier to transition from
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existing IEEE 802.3 10BASE2 Ethernet and IEEE 802.5 Token Ring networks
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by providing means to reuse existing cabling.
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This driver handles any number of cards installed in a single system.
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They get fddi0, fddi1, etc. interface names assigned in the order of
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increasing TURBOchannel slot numbers.
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The board only supports DMA on the receive side. Transmission involves
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the use of PIO. As a result under a heavy transmission load there will
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be a significant impact on system performance.
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The board supports a 64-entry CAM for matching destination addresses.
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Two entries are preoccupied by the Directed Beacon and Ring Purger
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multicast addresses and the rest is used as a multicast filter. An
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all-multi mode is also supported for LLC frames and it is used if
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requested explicitly or if the CAM overflows. The promiscuous mode
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supports separate enables for LLC and SMT frames, but this driver
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doesn't support changing them individually.
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Known problems:
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None.
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To do:
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5. MAC address change. The card does not support changing the Media
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Access Controller's address registers but a similar effect can be
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achieved by adding an alias to the CAM. There is no way to disable
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matching against the original address though.
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7. Queueing incoming/outgoing SMT frames in the driver if the SMT
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receive/RMC transmit ring is full. (?)
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8. Retrieving/reporting FDDI/SNMP stats.
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Both success and failure reports are welcome.
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Maciej W. Rozycki <macro@orcam.me.uk>
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