4. Addressing > Non-transparent Addressing
37
PEB383 User Manual
July 25, 2011
Integrated Device Technology, Inc.
Confidential - NDA Required
4.7
Non-transparent Addressing
At power-up, the host processor discovers the need for non-transparent bridging and enables the
address remapping of prefetchable, non-prefetchable, and I/O ranges through configuration. Before
enabling address remapping of the base and limit values, the remapped address ranges need to be
programmed. The
“Downstream Non-transparent Address Remapping Registers”
allow downstream
accesses to be mapped to arbitrary positions in PCI memory space. While the Memory Base and Limit
registers always define the range of addresses to be claimed on the PCIe link and forwarded to the PCI
bus, cycles that are claimed have their addresses modified because of the difference in the base
addresses of the windows on the two buses.
4.7.1
PCIe to PCI Non-prefetchable Address Remapping
Downstream transactions that fall within the address window defined by the
are remapped according to the address window defined by the
Non-prefetchable Address Remap Control Register”
and
“Secondary Bus Non-prefetchable Upper
. The following equations describe the address remapping process:
•
PriSecNPDiff = PriNPBase - SecNPBase, where
—
PriSecNPDiff
: Defines the difference between the Primary Non-prefetchable Base and the
Secondary Non-prefetchable Base.
—
PriNPBase
: Defined in the previous paragraph.
—
SecNPBase
: Defined by
“Secondary Bus Non-prefetchable Address Remap Control Register”
“Secondary Bus Non-prefetchable Upper Base Address Remap Register”
.
•
SecNPAddr = PriNPAddr - PriSecNPDiff, where
—
SecNPAddr
: Defines the remapped address that the PEB383 presents on the PCI bus.
—
PriNPAddr
: Defines the address presented to the PEB383 that falls within the registers
described in the previous paragraph.
—
PriSecNPDiff
: See previous bullet.
4.7.2
PCIe to PCI Prefetchable Address Remapping
Downstream transactions that fall within the address window defined by the
“PCI PFM Base Upper 32 Address Register”
“PCI PFM Limit Upper 32 Address
are remapped according to the address window defined by the
Address Remap Control Register”
and
“Secondary Bus Prefetchable Upper Base Address Remap
. The following equations describe the address remapping process:
•
PriSecPFDiff = PriPFBase - SecPFBase, where
—
PriSecPFDiff
: Defines the difference between the Primary Prefetchable Base and the
Secondary Prefetchable Base.
—
PriPFBase
:
Defined by the registers listed above.
—
SecPFBase
:
Defined by
“Secondary Bus Prefetchable Address Remap Control Register”
“Secondary Bus Prefetchable Upper Base Address Remap Register”