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Altera Embedded Peripherals IP User Manual

Page 141

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Each entry in the address translation table also has two address space indication bits, which specify the

type of address space being mapped. If the type of address space being mapped is memory, the bits also

indicate the resulting PCI address is a 32-bit address.

Table 14-4: Address Space Bit Encodings

Address

Space Indicator

(Bits 1:0)

Description

00

Memory space, 32-bit PCI address.
Address bits 63:32 of the translation table entries are ignored.

01

Reserved.

10

I/O space. The address from the translation table process is modified as described

in Configuration and I/O Space Address Modifications table.

11

Configuration space. The address from the translation table process is treated as a

type 1 configuration address and is modified as described in Configuration and I/

O Space Address Modifications table .

If the space indication bits specify configuration or I/O space, subsequent modifications to the PCI

address are performed..

Table 14-5: Configuration and I/O Space Address Modifications

Address Space

Modifications Performed

I/O

Address bits 2:0 are set to point to the first enabled byte according to the

Avalon byte enables. (Bit 2 only needs to be modified when a 64-bit data path

is in use.)
Address bits 31:3 are handled normally.

Configuration
address bits

23:16 == 0
(bus number ==

0)

Address bits 1:0 are set to

00

to indicate a type 0 configuration request.

Address bits 10:2 are passed through as normal.
Address bits 31:11 are set to be a one-hot encoding of the device number field

(15:11) of the address from the translation table. For example, if the device

number is

0x00

, address bit 11 is set to 1 and bits 31:12 are set to 0. If the

device number is

0x01

, address bit 12 is set to 1 and bits 31:13, 11 are set to 0.

Address bits 31:24 of the original PCI address are ignored.

Configuration
address bits

23:16 > 0
(bus number > 0)

Address bits 1:0 are set to

01

to indicate a type 1 configuration request.

Address bits 31:2 are passed through unchanged.

UG-01085

2014.24.07

Avalon-to-PCI Address Translation

14-7

PCI Lite Core

Altera Corporation

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