Device capabilities – Altera Stratix V Avalon-ST User Manual

Page 29

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Device Capabilities

Parameter

Possible

Values

Default

Value

Description

Maximum

payload size

128 bytes
256 bytes

128 bytes Specifies the maximum payload size supported. This parameter

sets the read-only value of the max payload size supported field

of the Device Capabilities register (0x084[2:0]). Address: 0x084.

Completion

timeout

range

ABCD

BCD

ABC

AB

B

A

None

ABCD

Indicates device function support for the optional completion

timeout programmability mechanism. This mechanism allows

system software to modify the completion timeout value. This

field is applicable only to Root Ports and Endpoints that issue

requests on their own behalf. Completion timeouts are

specified and enabled in the Device Control 2 register (0x0A8)

of the PCI Express Capability Structure Version. For all other

functions this field is reserved and must be hardwired to

0x0000b. Four time value ranges are defined:
• Range A: 50 us to 10 ms

• Range B: 10 ms to 250 ms

• Range C: 250 ms to 4 s

• Range D: 4 s to 64 s
Bits are set to show timeout value ranges supported. The

function must implement a timeout value in the range 50 s to

50 ms. The following values are used to specify the range:
• None—Completion timeout programming is not supported

• 0001 Range A

• 0010 Range B

• 0011 Ranges A and B

• 0110 Ranges B and C

• 0111 Ranges A, B, and C

• 1110 Ranges B, C and D

• 1111 Ranges A, B, C, and D
All other values are reserved. Altera recommends that the

completion timeout mechanism expire in no less than 10 ms.

Implement

completion

timeout

disable

On/Off

On

Disables the completion timeout mechanism. When On, the

core supports the completion timeout disable mechanism via

the PCI Express

Device Control Register 2

. The Applica‐

tion Layer logic must implement the actual completion timeout

mechanism for the required ranges. This option is forced to on

for PCI Express version 2.0 and higher Endpoints.

UG-01097_sriov

2014.12.15

Device Capabilities

3-9

Parameter Settings

Altera Corporation

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