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GT-96100A Advanced Communication Controller
Revision 1.0
67
3.6
Address Remapping
The GT-96100A supports address remapping on both the CPU interface and the PCI interfaces.
NOTE: Although the IDMA controllers use the CPU address decode registers, the source and destination DMA
addresses are NEVER remapped.
3.6.1
CPU Address Remapping
The resources that can be addressed by the CPU are the following:
SDRAM banks (SCS[1:0]*, SCS[3:2]*)
Devices (CS[2:0]*, CS[3]* & BootCS*)
PCI_0 IO
PCI_0 Memory0/1
PCI_1 IO
PCI_1 Memory0/1
NOTE: PCI_1 IO and PCI_1 Memory0/1 are only addressable if the device is configured for both PCI_0 and
PCI_1 on RESET.
Each resource addressed by the CPU has a Remap register associated with it. These registers are listed in
SectionAn address presented on the SysAD bus by the CPU is decoded with the following steps:
1. Address bits [35:21] are checked for a hit in the CPU decoders.
2. Assuming there is a hit in the CPU decoders, the HIT address will have bits 35:32 discarded. Bits 20:0
are left unchanged. Bits[31:21] are remapped as follows: Going from the most significant bit (MSB) to
least significant bit (LSB) of the HIT address bits [31:21], any bit found matching to its respective bit in
the LOW decode register’s bits [10:0] will cause the according bit in the remap register to REPLACE
the original address bit. Upon first mismatch, all remaining LSBs of address bits[31:21] are unchanged.
3. Address bits [31:20] of the remapped address are checked to be a hit in the Device decoders.
4. Assuming there is a hit in the Device decoders, the HIT address will be transferred to the resource.
See
Figure 6 outlining this address remapping procedure.
0x0.1F00.0000 to 0x0.1FFF.FFFF
16 Megabytes in Memory Space
CS[3]* and
BootCS*
0x0.1F00.0000 to
0x0.1FBF.FFFF
12 Megabyte
CS3*
0x0.1FC0.0000 to
0x0.1FFF.FFFF
4 Megabytes
BootCS*
Table 23: PCI Function 1 (Byte Order Swap) and
Device Decoder Default Address Mapping (Continued)
PCI Function 0 Deco de
Range and Size
Reso urce
Gro up
Device Decode
Range and Size
Device
Selected