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Chapter 5: IP Core Architecture
5–17
Completer Only Single Dword Endpoint
June 2012
Altera Corporation
Stratix V Hard IP for PCI Express
■
Bits [23:20] select the address translation table entry.
■
Bits [63:20] of the address translation table entry become PCI Express address bits
[63:20].
■
Bits [19:0] are passed through and become PCI Express address bits [19:0].
The address translation table is dynamically configured at run time. The address
translation table is implemented in memory and can be accessed through the CRA
slave module. Dynamic configuration is optimal in a typical PCI Express system
where address allocation occurs after BIOS initialization.
For more information about how to access the dynamic address translation table
through the CRA slave, refer to the
“Avalon-MM-to-PCI Express Address Translation
Table 0x1000–0x1FFF” on page 7–15
depicts the Avalon-MM-to-PCI Express address translation process.
Completer Only Single Dword Endpoint
The completer only single dword endpoint is intended for applications that use the
PCI Express protocol to perform simple read and write register accesses from a host
CPU. The completer only single dword endpoint is a hard IP implementation
available for Qsys systems, and includes an Avalon-MM interface to the Application
Layer. The Avalon-MM interface connection in this variation is 32 bits wide. This
endpoint is not pipelined; at any time a single request can be outstanding.
The completer-only single dword endpoint supports the following requests:
■
Read and write requests of a single dword (32 bits) from the Root Complex
Figure 5–8. Avalon-MM-to-PCI Express Address Translation
(1)
,
(2)
,
(3)
,
(4)
,
(5)
Notes to
(1)
N
is the number of pass-through bits.
(2)
M
is the number of Avalon-MM address bits.
(3)
P
is the number of PCI Express address bits.
(4)
Q
is the number of translation table entries.
(5)
Sp[1:0]
is the space indication for each entry.
PCIe Address Q-1
SpQ-1
Space Indication
PCI Express address from Table Entry
becomes High PCI Express address bits
PCI Express Address
High
Low
P-1
N N-1
0
Low address bits unchanged
Avalon-MM-to-PCI Express
Address Translation Table
(Q entries by P-N bits wide)
PCIe Address 0
Sp0
PCIe Address 1
Sp1
Avalon-MM Address
High
Slave Base
Address
Low
M-1
31
M
N N-1
0
Table updates from
control register port
High Avalon-MM Address
Bits Index table