Intel E3845 FH8065301487715 Scheda Tecnica
Codici prodotto
FH8065301487715
Mapping Address Spaces
Intel
®
Atom™ Processor E3800 Product Family
Datasheet
69
4
Mapping Address Spaces
The SoC supports four different address spaces:
•
•
•
•
Message Bus Space
The CPU core can only directly access memory space through memory reads and writes
and IO space through the
and IO space through the
IN
and
OUT
IO port instructions. PCI configuration space is
indirectly accessed through IO or memory space, and the Message Bus space is
accessed through PCI configuration space. See
accessed through PCI configuration space. See
for details.
This chapter describes how the memory, IO, PCI and Message Bus spaces are mapped
to interfaces in the SoC.
to interfaces in the SoC.
Note:
See
for registers specified in the chapter.
4.1
Physical Address Space Mappings
There are 64 GB (36-bits) of physical address space that can be used as:
•
Memory Mapped IO (MMIO - IO fabric)
•
Physical Memory (DRAM)
The CPU core can access the full physical address space, while downstream devices can
only access SoC DRAM, and each CPU core’s local APIC. Peer to peer transactions are
not supported.
only access SoC DRAM, and each CPU core’s local APIC. Peer to peer transactions are
not supported.
Most devices map their registers and memory to the physical address space. This
chapter summarizes the possible mappings.
chapter summarizes the possible mappings.
4.1.1
SoC Transaction Router Memory Map
The SoC Transaction Router maps the physical address space as follows:
•
CPU core to DRAM
•
CPU core to IO fabric (MMIO)
•
CPU core to extended PCI registers (ECAM accesses)
•
IO fabric to CPU cores (local APIC interrupts)
Although 64 GB (36-bits) of physical address space is accessible, some MMIO must
exist for devices and software with 32-bit limits. Further, all DRAM should remain
accessible for devices and software with access to memory above 4 GB. These goals
exist for devices and software with 32-bit limits. Further, all DRAM should remain
accessible for devices and software with access to memory above 4 GB. These goals