dppb(7)                        DG/UX R4.11MU05                       dppb(7)


NAME
       dppb - DEC PCI-to-PCI Bus Bridge

SYNOPSIS
       dppb(parent-bus[,pci-device-num[,pci-function-num]])


DESCRIPTION
       The dppb bus bridge device driver allows an AViiON system to access
       Peripheral Component Interconnect (PCI) devices via a DEC 21x5x-
       series PCI-to-PCI bus bridge.  Such a bridge links one PCI bus
       (usually a host bridge) to a new subordinate PCI bus that can
       accommodate additional PCI controller devices.  Typically, the bridge
       and its subordinate devices are integrated onto a single expansion
       card, such as a multi-channel LAN or multi-channel SCSI card.  Even
       though there is only one physical card in such a scenario, the bridge
       and each of its subordinate LAN or SCSI interfaces are each accessed
       as separate individual devices.

       To access a PCI device via the interface, you must specify the
       appropriate dppb bridge as the parent bus device within the name of a
       PCI device to be configured (e.g., apsc or dpen).  See the pci_bus(7)
       man page for a list of the supported child PCI devices; each man page
       name in the list is the name of a PCI device driver.

       To configure dppb bridge devices, you must add to the DG/UX system
       configuration file one or more device name entries that contain one
       of the forms described in the synopsis above.  The parameters in a
       device name have the following meanings:

       ·   The parent-bus parameter is itself a device name, representing
           the PCI bus device to which the bridge is attached (pci(0), for
           example).  There is no default value for this parameter; it must
           always be specified explicitly.

       ·   The pci-device-num parameter is a hexadecimal number in the range
           0 through 1F; it represents the PCI device number ("slot number")
           used by the device.  The default value for pci-device-num is 0.

       ·   The pci-function-num parameter is a hexadecimal number in the
           range 0 through 7 that represents the PCI function number used by
           the bridge within pci-device-num.  The default value for pci-
           device-num is 0; non-zero values will be used only if the bridge
           lies on a multi-function card.

EXAMPLES
       The following entry in a DG/UX configuration file configures the DEC
       PCI Ethernet controller on PCI device number 5 of the DEC bridge in
       slot 3 of the first Corollary PCI host bridge:

            dpen(dppb(cpci(0),3),5)


       The following entry in a DG/UX configuration file configures the SCSI
       disk on SCSI ID 2 of the Adaptec PCI SCSI adapter that is on PCI
       device number 4 of the DEC bridge in the expansion slot (PCI device
       number 2) of the sixteenth Integrated PCI host bridge:

            sd(apsc(dppb(gpci(F),2),4),2)



       For more information about DG/UX device configuration, refer to
       "Writing a Device Driver" in Programming in the DG/UX Kernel
       Environment.

SEE ALSO
       pci_bus(7).


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