Configuration Transmit Message Interface - 3.4 English

Versal Adaptive SoC CPM Mode for PCI Express Product Guide (PG346)

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3.4 English

The configuration transmit message interface is used by the user application to transmit messages to the core. The user application supplies the transmit message type and data information to the core, which responds with the done signal. The following table defines the ports in the configuration transmit message interface of the core.

Note: The pcie0* signals map to PCIe Controller 0 and pcie1* signals map to PCIe Controller 1 in the port descriptions below.
Table 1. Configuration Transmit Message Interface
Port I/O Width Description


I 1

Configuration transmit encoded message.

This signal is asserted together with cfg_msg_transmit_type, which supplies the encoded message type and cfg_msg_transmit_data, which supplies optional data associated with the message, until cfg_msg_transmit_done is asserted in response.


I 3

Configuration Transmit Encoded Message Type.

Indicates the type of PCI Express message to be transmitted. Encodings supported are:

  • 000b: Latency Tolerance Reporting (LTR)
  • 001b: Optimized Buffer Flush/Fill (OBFF)
  • 010b: Set Slot Power Limit (SSPL)
  • 011b: Power Management (PM PME)
  • 100b -111b: Reserved


I 32

Configuration Transmit Encoded Message Data.

Indicates message data associated with particular message type.

000b: LTR

  • cfg_msg_transmit_data[31] < Snoop Latency Req
  • cfg_msg_transmit_data[30:29] <= Repurposing to pass PASID information. assigned to s_axis_rq_tuser[182:181] inside the IP.
  • cfg_msg_transmit_data[28:26] < Snoop Latency Scale
  • cfg_msg_transmit_data[25:16] < Snoop Latency Value
  • cfg_msg_transmit_data[15] < No-Snoop Latency Requirement
  • cfg_msg_transmit_data[14:13] <= Repurposing to pass PASID information. assigned to s_axis_rq_tuser[180:179] inside the IP.
  • cfg_msg_transmit_data[12:10] < No-Snoop Latency Scale
  • cfg_msg_transmit_data[9:0] < No-Snoop Latency Value

001b: Reserved.

010b: SSPL

  • cfg_msg_transmit_data[9:0] < {Slot Power Limit Scale, Slot Power Limit Value}

011b: PM_PME

  • cfg_msg_transmit_data[7:0] <= 8'h00-8'hFF

    PF0-3 - 8'h00-8'h03 Other encodings are reserved

100b - 111b: Reserved

pcie0_cfg_msg_transmit_done O 1

Configuration Transmit Encoded Message Done.

Asserted in response to cfg_mg_transmit assertion, for 1 cycle after the request is complete.