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
34
Section 3: System Overview
Document
1250_1125-UM100CB-R
M
EMORY
M
AP
The memory map is designed to be usable in systems that only have 32 bit addressing and to provide
expansion for systems that can support the full 64 bit virtual address and 40 bit physical address of the SB-1
CPU. There are some additional restrictions that the MIPS architecture imposes:
•
The reset vector of the CPU is to physical address
00_1FC0_0000
.
•
The exception vectors of the CPU are at physical address
00_0000_0000
. (They may be offset from the
base by a multiple of 64K using the SB-1 MultiProcessor Vector extension in the CPU config register).
•
The first 512 MB of memory is addressable uncached (and unmapped) in KSEG1 and is therefore a good
place for fixed address peripherals (they can be accessed without using any TLB entries).
In addition devices on the PCI need to be able to DMA into all of the physical memory (within the 32 bit PCI
address range) and be able to enable or disable endian swapping on each transaction (see
for a full discussion of PCI and HyperTransport endian policies). An overview of the
and
and a more detailed view is in
Table 10: Overview of BCM1250 Physical Address Map
Base
Top
Owner
00_0000_0000
00_0FFF_FFFF
Memory controller.
00_1000_0000
00_1005_FFFF
System control and debug.
00_1006_0000
00_3FFF_FFFF
I/O system.
00_4000_0000
00_5FFF_FFFF
HyperTransport/PCI memory mapped I/O (32 bit addressing range)
Match byte lane endian policy.
00_6000_0000
00_7FFF_FFFF
HyperTransport/PCI memory mapped I/O (32 bit addressing range)
Match bit lane endian policy.
00_8000_0000
00_9FFF_FFFF
Memory controller.
00_A000_0000
00_BFFF_FFFF
Reserved
00_C000_0000
00_CFFF_FFFF
Memory controller.
00_D000_0000
00_D7FF_FFFF
L2 controller test.
00_D800_0000
00_D92F_FFFF
HyperTransport special operations Match byte lane endian policy. Not on
BCM1125.
00_DC00_0000
00_DDFF_FFFF
HyperTransport/PCI I/O space Match byte lane endian policy.
00_DE00_0000
00_DFFF_FFFF
HyperTransport/PCI configuration space Match byte lane endian policy.
00_E000_0000
00_F7FF_FFFF
Reserved
00_F800_0000
00_F92F_FFFF
HyperTransport special operations Match bit lane endian policy. Not on
BCM1125.
00_FC00_0000
00_FDFF_FFFF
HyperTransport/PCI I/O space Match bit lane endian policy.
00_FE00_0000
00_FFFF_FFFF
HyperTransport/PCI configuration space Match bit lane endian policy.
01_0000_0000
7F_FFFF_FFFF
Memory controller expansion.
80_0000_0000
F7_FFFF_FFFF
HyperTransport expansion (40 bit addressing range). Not on BCM1125.
F8_0000_0000
F8_FFFF_FFFF
PCI bus full access (match byte lane endian policy).
F9_0000_0000
F9_FFFF_FFFF
PCI bus full access (match bit lane endian policy).
FA_0000_0000
FC_FFFF_FFFF
Reserved
FD_0000_0000
FF_FFFF_FFFF
Reserved (Special HyperTransport range).