Intel Xeon Wolfdale E3210 P4X-UPE3210-316-6M1333 データシート
製品コード
P4X-UPE3210-316-6M1333
Datasheet
59
MCH Register Description
The MCH is responsible for translating and routing the processor’s I/O accesses to the
CONFIG_ADDRESS and CONFIG_DATA registers to internal MCH configuration
registers, DMI or PCI Express.
CONFIG_ADDRESS and CONFIG_DATA registers to internal MCH configuration
registers, DMI or PCI Express.
4.3.2
PCI Express Enhanced Configuration Mechanism
PCI Express extends the configuration space to 4096 bytes per device/function as
compared to 256 bytes allowed by PCI Specification Revision 2.3. PCI Express
configuration space is divided into a PCI 2.3 compatible region, which consists of the
first 256B of a logical device’s configuration space and a PCI Express extended region,
which consists of the remaining configuration space.
compared to 256 bytes allowed by PCI Specification Revision 2.3. PCI Express
configuration space is divided into a PCI 2.3 compatible region, which consists of the
first 256B of a logical device’s configuration space and a PCI Express extended region,
which consists of the remaining configuration space.
The PCI compatible region can be accessed using either the Standard PCI Configuration
Mechanism or using the PCI Express Enhanced Configuration Mechanism described in
this section. The extended configuration registers may only be accessed using the PCI
Express Enhanced Configuration Mechanism. To maintain compatibility with PCI
configuration addressing mechanisms, system software must access the extended
configuration space using 32-bit operations (32-bit aligned) only. These 32-bit
operations include byte enables allowing only appropriate bytes within the DWord to be
accessed. Locked transactions to the PCI Express memory mapped configuration
address space are not supported. All changes made using either access mechanism are
equivalent.
Mechanism or using the PCI Express Enhanced Configuration Mechanism described in
this section. The extended configuration registers may only be accessed using the PCI
Express Enhanced Configuration Mechanism. To maintain compatibility with PCI
configuration addressing mechanisms, system software must access the extended
configuration space using 32-bit operations (32-bit aligned) only. These 32-bit
operations include byte enables allowing only appropriate bytes within the DWord to be
accessed. Locked transactions to the PCI Express memory mapped configuration
address space are not supported. All changes made using either access mechanism are
equivalent.
The PCI Express Enhanced Configuration Mechanism utilizes a flat memory-mapped
address space to access device configuration registers. This address space is reported
by the system firmware to the operating system. There is a register, PCIEXBAR, that
defines the base address for the block of addresses below 4 GB for the configuration
space associated with busses, devices and functions that are potentially a part of the
PCI Express root complex hierarchy. In the PCIEXBAR register there exists controls to
limit the size of this reserved memory mapped space. 256 MB is the amount of address
space required to reserve space for every bus, device, and function that could possibly
exist. Options for 128 MB and 64 MB exist in order to free up those addresses for other
uses. In these cases the number of busses and all of their associated devices and
functions are limited to 128 or 64 busses respectively.
address space to access device configuration registers. This address space is reported
by the system firmware to the operating system. There is a register, PCIEXBAR, that
defines the base address for the block of addresses below 4 GB for the configuration
space associated with busses, devices and functions that are potentially a part of the
PCI Express root complex hierarchy. In the PCIEXBAR register there exists controls to
limit the size of this reserved memory mapped space. 256 MB is the amount of address
space required to reserve space for every bus, device, and function that could possibly
exist. Options for 128 MB and 64 MB exist in order to free up those addresses for other
uses. In these cases the number of busses and all of their associated devices and
functions are limited to 128 or 64 busses respectively.
The PCI Express Configuration Transaction Header includes an additional 4 bits
(ExtendedRegisterAddress[3:0]) between the Function Number and Register Address
fields to provide indexing into the 4 KB of configuration space allocated to each
potential device. For PCI Compatible Configuration Requests, the Extended Register
Address field must be all zeros.
(ExtendedRegisterAddress[3:0]) between the Function Number and Register Address
fields to provide indexing into the 4 KB of configuration space allocated to each
potential device. For PCI Compatible Configuration Requests, the Extended Register
Address field must be all zeros.