Chapter 5: IP Core Architecture
5–17
Avalon-MM Bridge TLPs
November 2012
Altera Corporation
Arria V GZ Hard IP for PCI Express
3. A TLP received with address 0x00001234 56789870
4. The upper 52 bits (0x0000123456789) are used in the BAR matching process, so this
request matches.
5. The lower 12 bits, 0x870, are passed through as the Avalon address on the
Rxm_BAR0 Avalon-MM Master port. The BAR matching software replaces the
upper 20 bits of the address with the Avalon-MM base address.
Minimizing BAR Sizes and the PCIe Address Space
For designs that include multiple BARs, you may need to modify the base address
assignments auto-assigned by Qsys in order to minimize the address space that the
BARs consume. For example, consider a Qsys system with the following components:
■
Offchip_Data_Mem DDR3
(SDRAM Controller with UniPHY) controlling 256
MBytes of memory—Qsys auto-assigned a base address of 0x00000000
■
Quick_Data_Mem
(On-Chip Memory (RAM or ROM)) of 4 KBytes—Qsys
auto-assigned a base address of 0x10000000
■
Instruction_Mem
(On-Chip Memory (RAM or ROM)) of 64 KBytes—Qsys
auto-assigned a base address of 0x10020000
■
PCIe
(Avalon-MM Arria V GZ Hard IP for PCI Express)
■
Cra
(Avalon-MM Slave)—auto assigned base address of 0x10004000
■
Rxm_BAR0
connects to
Offchip_Data_Mem DDR3 avl
■
Rxm_BAR2
connects to
Quick_Data_Mem s1
■
Rxm_BAR4
connects to PCIe.
Cra
Avalon-MM Slave
■
Nios2
(Nios
®
II Processor)
■
data_master
connects to
PCIe Cra
,
Offchip_Data_Mem DDR3 avl
,
Quick_Data_Mem s1
,
Instruction_Mem s1
,
Nios2
jtag_debug_module
■
instruction_master
connects to
Instruction_Mem
s1