Scalable Scatter-Gather DMA Intel® FPGA IP User Guide

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ID 823097
Date 4/07/2025
Public
Document Table of Contents
Document Table of Contents x
1. Terms and Acronyms 2. Introduction 3. Functional Description 4. Interfaces 5. HAL Driver for DMA SoC Mode  6. Parameters 7. Registers 8. Document Revision History for the Scalable Scatter-Gather DMA Intel® FPGA IP User Guide
2. Introduction x
2.1. Device Family Support 2.2. Release Information 2.3. Resource Utilization
3. Functional Description x
3.1. DMA PCIe* Mode 3.2. DMA SoC Mode 3.3. Device Port 3.4. Prefetcher Engine 3.5. DMA Arbiter 3.6. DMA Router 3.7. CSRUnit 3.8. Descriptor Handling 3.9. Interrupts 3.10. Reset Initialization Flows 3.11. Transaction Flow
3.1. DMA PCIe* Mode x
3.1.1. Submodules
3.1.1. Submodules x
3.1.1.1. PCIe* TLP Constructor 3.1.1.2. PCIe* TLP ID Generation 3.1.1.3. PCIe TX Credit Controller 3.1.1.4. PCIe* TX Scheduler 3.1.1.5. PCIe TLP Completer 3.1.1.6. PCIe RX Router 3.1.1.7. PCIe* MSI-X Controller 3.1.1.8. PCIe BAR0 3.1.1.9. PCIe Bursting Manager (BAM) 3.1.1.10. Completion Timeout Parser 3.1.1.11. Control Shadow Parser
3.2. DMA SoC Mode x
3.2.1. Interrupt Controller 3.2.2. Host AXI-4 Agent 3.2.3. Host CSR AXI-4 Lite Agent
3.3. Device Port x
3.3.1. ST Source Agent/ST Sink Agent/MM Agent 3.3.2. Descriptor Engine 3.3.3. Agent Controller 3.3.4. Constructor 3.3.5. Responder 3.3.6. Width Adaptation FIFO
3.8. Descriptor Handling x
3.8.1. Link Descriptor 3.8.2. Data Descriptor 3.8.3. Responder Descriptor 3.8.4. Descriptor Chain 3.8.5. Aligned and Unaligned Transfer Support
3.8.2. Data Descriptor x
3.8.2.1. Data Descriptor - H2D Streaming Transfer 3.8.2.2. Data Descriptor - D2H Streaming Transfer 3.8.2.3. Data Descriptor - H2D Memory Transfer
3.8.3. Responder Descriptor x
3.8.3.1. Responder Descriptor - H2D Streaming Transfer 3.8.3.2. Responder Descriptor - D2H Streaming Transfer 3.8.3.3. Responder Descriptor - H2D Memory Transfer
3.8.4. Descriptor Chain x
3.8.4.1. Descriptor Fetch and Status Update Mechanism
3.11. Transaction Flow x
3.11.1. General DMA Operation Flow 3.11.2. Host to Device (H2D) Flow 3.11.3. Device to Host (D2H) Flow 3.11.4. Soft Reset Handshake Flow
4. Interfaces x
4.1. Port List 4.2. DMA PCIe* Mode Interfaces 4.3. DMA SoC Mode Interfaces 4.4. Device Port Interfaces 4.5. Resets 4.6. Clocks
4.2. DMA PCIe* Mode Interfaces x
4.2.1. Application Packet Receive Interface 4.2.2. Application Packet Transmit Interface 4.2.3. Control Shadow Interface 4.2.4. Transmit Flow Control Credit Interface 4.2.5. Completion Timeout Interface 4.2.6. PCIe* Miscellaneous Signals 4.2.7. Control and Status Register Responder Manager Interface 4.2.8. Bursting Manager Interface
4.3. DMA SoC Mode Interfaces x
4.3.1. Host AXI-4 Memory Map Manager Interface 4.3.2. Host AXI-4 Lite CSR Memory Map Subordinate Interface 4.3.3. Interrupt Interface
4.4. Device Port Interfaces x
4.4.1. Device to Host <PORT#> AXI-ST Subordinate Interface 4.4.2. Device to Host <PORT#> Avalon-ST Sink Interface 4.4.3. Host to Device <PORT#> AXI-ST Manager Interface 4.4.4. Host to Device <PORT#> Avalon-ST Source Interface 4.4.5. Host to Device <PORT#> AXI-4 Manager Interface
5. HAL Driver for DMA SoC Mode  x
5.1. Descriptor Indexing  5.2. HAL Public API 
5.1. Descriptor Indexing  x
5.1.1. Data Descriptors  5.1.2. Responders 
5.2. HAL Public API  x
5.2.1. Software Features 5.2.2. intel_ssgdma.c  5.2.3. intel_ssgdma_global.c 5.2.4. intel_ssgdma_device_port.c  5.2.5. intel_ssgdma_descriptor.c 
6. Parameters x
6.1. DMA Settings 6.2. Device Port Settings 6.3. DMA PCIe Mode Settings 6.4. DMA SoC Mode Settings 6.5. Example Design
6.2. Device Port Settings x
6.2.1. H2D MM 6.2.2. H2D ST 6.2.3. D2H ST
7. Registers x
7.1. Global CSR 7.2. MSI-X Memory Space 7.3. Device Port Control Register
1. Terms and Acronyms
2. Introduction
3. Functional Description
4. Interfaces
5. HAL Driver for DMA SoC Mode 
6. Parameters
7. Registers
8. Document Revision History for the Scalable Scatter-Gather DMA Intel® FPGA IP User Guide

3.8.1. Link Descriptor

Table 11.  Link Descriptor Format
Offset Byte Lanes
3 2 1 0
0x00 DescrIDX Control

FormatField[7:0]

0b00xx_xx01
0x04 Reserved. Set to 0.
0x08 NextBlockAddress[31:0]
0x0C NextBlockAddress[63:32]
0x10-0x1C Reserved. Set to 0.
Table 12.  Link Descriptor — Field Description
Field Description
DescrIDX

Unique Identifier for each descriptor. This value is updated to the following value:

  • Q_EXTRACT_POINTER register when a descriptor data transfer is complete.
Note: The value of DescrIDX cannot be 0. It must be incremented by 1. Once DescrIDX reaches the maximum value (number of descriptor block *128), the subsequent DescrIDX value should rollover. Refer to Figure Descriptor Chain / Ring buffer for Descriptor Blocks (Continuous Ring) and Figure Descriptor Chain for Descriptor Blocks (Stop at Last Descriptor) for examples of DescrIDX values.
Control The control field in the Link descriptor block.
NextBlockAddress

The address of the next 4kB page/descriptor block in host memory containing the descriptors.

Note: If there is only one 4kB page/descriptor block is allocated, the NextBlockAddress values must be configured to the values as defined in Q_START_ADDR_L & Q_START_ADDR_H CSR registers.

The NextBlockAddress and Q_START_ADDR_* from Device Port CSR configured by software must be aligned to 4kB page boundary by setting NextBlockAddress[11:0] and Q_START_ADDR_L[11:0] to zero.

Table 13.  Link Descriptor — Control Field
Bit Field Description
6:0 Reserved Set to 0.
7 DescValid

If set, indicate the current link descriptor content is valid.

Notes: This bit must set to high always by software.
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