Hawk PCI Host Bridge & Multi-Processor Interrupt Controller
2
The PSOFFx (PCI Slave Offset Registers) contain offset information
associated with the mapping of PCI memory space to PPC memory space.
The field within the PSOFFx registers is defined as follows:
CONFIG_ADDRESS Register
The description of the CONFIG_ADDRESS register is presented in three
perspectives: from the PCI bus, from the PPC Bus in Big-Endian mode,
and from the PPC bus in Little-Endian mode.
Note
2-100
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RMFTx (Read Multiple FIFO Threshold) This field is used by the
PHB to determine a FIFO threshold at which to continue prefetching
data from local memory during PCI read multiple transactions. This
threshold applies to subsequent prefetch reads since all initial prefetch
reads will be four cache lines. This field is only applicable if read-
ahead has been enabled. The encoding of this field is shown in the
table below.
RMFT/RXFT
Subsequent Prefetch FIFO Threshold
00
01
10
11
PSOFFx (PCI Slave Offset) This register contains a 16-bit offset that
is added to the upper 16 bits of the PCI address to determine the PPC
address used for transfers from PCI to the PPC bus. This offset allows
PPC resources to reside at addresses that would not normally be visible
from PCI.
The view from the PCI bus is purely conceptual, since there is no
way to access the CONFIG_ADDRESS register from the PCI
bus.
0 Cache lines
1 Cache line
2 Cache lines
3 Cache lines
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