Data Sheet

PCIe Programming Interface—Ethernet Controller I210
625
9.5.4.1 LTR CAP ID (0x1C0; RO)
9.5.4.2 LTR Capabilities (0x1C4; RW)
Bit
Location
Attribute
Default
Value
Description
15:0 RO 0x18
LTR Capability ID
PCIe extended capability ID indicating LTR capability.
19:16 RO 0x1
Version Number
PCIe LTR extended capability version number.
31:20 RO 0x000 Next Capability Pointer
Bit
Location
Attribute
Default
Value
Description
9:0 RW 0x0
Maximum Snoop Latency Value
Along with the Max Snoop Latency Scale field, this register specifies the maximum nosnoop
latency that a device is permitted to request. Software
should set this to the platform’s maximum supported latency or less.
Field is also an indicator of the platforms maximum latency, should an endpoint send up LTR
Latency Values with the Requirement bit not set.
12:10 RW 0x0
Max Snoop Latency Scale
This field provides a scale for the value contained within the Maximum Snoop Latency Value
field.
Encoding:
000 – Value times 1ns
001 – Value times 32ns
010 – Value times 1,024ns
011 – Value times 32,768ns
100 – Value times 1,048,576ns
101 – Value times 33,554,432ns
110-111 – Not Permitted
15:13 RO 0x0 Reserved
25:16 RW 0x0
Max No-Snoop Latency Value
Along with the Max No-Snoop Latency Scale field, this register specifies the maximum no-
snoop latency that a device is permitted to request. Software should set this to the platform’s
maximum supported latency or less.
Field is also an indicator of the platforms maximum latency, should an
endpoint send up LTR Latency Values with the Requirement bit not set.
28:26 RW 0x0
Max No-Snoop Latency Scale — This register provides a scale for the value contained within
the Maximum Non-Snoop Latency Value field.
Encoding:
000 – Value times 1 ns
001 – Value times 32 ns
010 – Value times 1,024 ns
011 – Value times 32,768 ns
100 – Value times 1,048,576 ns
101 – Value times 33,554,432 ns
110-111 – Not Permitted
31:29 RO 0x0 Reserved.