BCM1250/BCM1125/BCM1125H
User Manual
10/21/02
B r o a d c o m C o r p o r a t i o n
Page
228
Section 8: PCI Bus and HyperTransport Fabric
Document
1250_1125-UM100CB-R
7.7 Address Remapping Capability Block
The interface does not have an address remapping block, the mappings between the ZBbus
and HyperTransport addresses are discussed in the earlier sections of this chapter.
8 System Management
The interface does not support any of the legacy x86 system management or special cycles.
The optional LDTSTOP# is not supported.
9 Address Map
The internal address map (
) reflects the requirements of the
HyperTransport map.
Only interrupts with Address[31:24]=F8 are accepted.
10.1 Error Conditions
The interface detects and reports the errors described in this section. Since the method of
detection and reporting were not specified in earlier versions of the HyperTransport
Specification the implementation differs.
10.1.1 Transmission Errors
A CRC error is detected and reported as in the specification. The sync flood control is in the
Link Control register as specified. The interrupt enable bits are in the HyperTransport Error
Control Register (
) rather than the new Error Handling Register in the
extended register set.
When a CRC error is detected the expected and received CRC values are logged in the
HyperTransport Diagnostic Receive CRC Expected (
) and Received
) registers.
10.1.3 Protocol Errors, 10.1.4 Receive Buffer Overflow Errors
Protocol and Overflow errors are reported in the HyperTransport Error Status Register
(
) rather than the new Link Error Register, and controlled in the
HyperTransport Error Control Register (
) rather than the new Error
Handling Register in the extended register set.
10.1.5 End of Chain Errors
The end of chain error is reported in the EocNxaError flag in the HyperTransport Error Status
Register (
) and controlled in the HyperTransport Error Control Register
The MapNxaError flag is used to report two variants of the issue described in the spec as Host
Inbound End Of Chain error. A MapNxaError is flagged when a posted operation is received
that is to an address that is not on the HyperTransport link or PCI and does not decode to a
legal address within the BCM1250. It is also flagged and the transaction dropped, for a posted
operation if the srcid is zero (i.e. it has come from the other host on a double-hosted chain) and
the destination is an address on the HyperTransport link. In this second case the transaction
has already been rejected by all devices on the link, and sending it back will just lead to the
transaction looping forever.
10.1.6 Chain Down Errors
The host interface discards all state on a link RESET# and does not report a chain down error.
Responses for in-flight reads will be lost and the requestor may hang.