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Table of Contents

Introduction

This page gives an overview of zdma driver which is available as part of the Xilinx Vivado and

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Vitis distribution.

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ZDMA is a general purpose DMA designed to support memory to memory and memory to IO buffer transfers.

Zynq

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Ultrascale+ MPSOC has two instance of general purpose ZDMA.
One is located in FPD (full power domain) which usually called as GDMA and other is located in LPD (low power domain) which usually called as ADMA.

Versal has one instance of general purpose DMA in LPD (low power domain) known as ADMA.

How to enable

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For more information, please refer to ADMA/GDMA chapter in ZynqMP TRM (UG1085) or Versal TRM (AM011).

Driver Sources

The source code for the driver is included with the Vitis Unified Software Platform installation, as well as being available in the Xilinx Github repository. 

Driver Name

Path in Vitis

Path in Github

emapcs

<Vitis Install Directory>/data/embedded/XilinxProcessorIPLib/drivers/zdma

https://github.com/Xilinx/embeddedsw/tree/master/XilinxProcessorIPLib/drivers/zdma


Note: To view the sources for a particular release, use the rel-version tag in github.  For example, for the 2020.1 release, the proper version of the code is: https://github.com/Xilinx/embeddedsw/tree/

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The driver source code is organized into different folders.

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  The table below shows the

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ZDMA driver source organization

Directory

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Description

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doc

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Provides the API and data structure details

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data

Driver .tcl and .mdd file

examples

Example applications that show how to use the driver

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features

src

Driver source files

Features Supported

Controller Features

  • Configurable AXI bus width
  • AXI 4 support , burst length is limited to 16 to provide AXI 3 compatibility
  • SRC and DST payload can start and end at any alignment
  • Over fetching can be enabled/disabled per channel
  • Up to 8 configurable DMA channels
  • Each channel can be programmed secure or non-secure
  • Programmable number of outstanding transactions per channel
  • Support for periodic transaction scheduling. Period can be independently programmed per channel
  • Supports Simple(descriptor less) and Scatter Gather (SG) DMA modes
  • Supports read only DMA mode
  • Supports write only DMA mode
  • Common Buffer is automatically shared among all enabled DMA channels
  • Support for DMA START, STOP and PAUSE
  • Interrupt Accounting support
  • Descriptor prefetch support to maximize DMA efficiency
  • Support for error recovery
  • INCR & FIXED type burst supported
  • Independent AXI burst length is supported on SRC & DST Side
  • Support for per channel flow control interface

Standalone Driver Supported Features

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Driver Implementation

For a full list of features supported by this IP, please refer to ADMA/GDMA chapter in ZynqMP TRM (UG1085) or Versal TRM (AM011) for respective devices.

Features

Controller/Driver features supported

  • GMDA & ADMA are configured each with 8 DMA channels and and each channel can be programmed secure or non-secure.

  • It support two DMA Modes

    • Simple DMA mode

      • Normal data transfer from source to destination

      • Write Only Mode

      • Read Only Mode

    • Scatter Gather DMA mode

      • Normal data transfer from source to destination

  • In Scatter gather Mode it supports 2 types of descriptors out of 3 that h/w supports

    • Linear descriptor

    • Linked list descriptor

  • Interrupt Accounting Support

  • INCR and Fixed burst are supported.

Known Issues and Limitations

  • Hybrid list descriptors are not supported.

  • Flow controller feature is not supported

  • Peripheral DMA is not tested/supported.

Test cases

  • Refer below pah for testing differnet examples for each feature of the IP.

Example Applications

ZDMA driver supports a interrupt examples in various operating modes describing how its different features can be exercised. These example applications can be imported into the Vitis IDE from the Board Support Package settings tab. 

Links to Examples

Examples Path:
https://github.com/Xilinx/embeddedsw/tree/master/XilinxProcessorIPLib/drivers/zdma/examples

Test Name

Example Source

Description

ZDMA Selftest example

xzdma_selftest_example.c

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Basic ZDMA selftest example to check sanity and use core APIs.

ZDMA Write-only example

xzdma_writeonlymode_example.c

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ZDMA example demonstrating write-only feature.

ZDMA Read-only example

xzdma_readonlymode_example.c

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ZDMA example demonstrating read-only feature.

ZDMA SG Linear example

xzdma_linear_example.c

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ZDMA example demonstrating Scatter Gather Linear descriptor mode.

ZDMA SG Linked list example

xzdma_linkedlist_example.c

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ZDMA example demonstrating Scatter Gather Linked list descriptor mode.

ZDMA Simple DMA example

xzdma_simple_example.c

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Known issues and Limitations

  • Hybrid list descriptors are not supported.
  • Flow controller feature is not supported
  • Peripheral dma is not tested/supported.

Change Log

2020.2
Summary:
  • Enable applications to use scatter-gather and enable APIs independently.
  • Support for parallel makefile execution

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ZDMA example demonstrating Simple DMA mode.

Example Application Usage

ZDMA Selftest example

Basic ZDMA selftest example to check sanity and use core APIs.

Expected Output

Successfully ran ZDMA Selftest Example

ZDMA Write-only example

ZDMA example demonstrating write-only feature.

Expected Output

Successfully ran Write Only mode ZDMA Example

ZDMA Read-only example

ZDMA example demonstrating read-only feature.

Expected Output

Successfully ran ZDMA Read Only Example

ZDMA SG Linear example

ZDMA example demonstrating Scatter Gather Linear descriptor mode.

Expected Output

Successfully ran ZDMA Linear mode Example

ZDMA SG Linked list example

ZDMA example demonstrating Scatter Gather Linked list descriptor mode.

Expected Output

Successfully ran ZDMA Linked list Example

ZDMA Simple DMA example

ZDMA example demonstrating Simple DMA mode.

Expected Output

Successfully ran ZDMA Simple Example

Example Design Architecture

NA

Performance

NA

Change Log

2021.1

https://github.com/Xilinx/embeddedsw/blob/xilinx_v2021.1/doc/ChangeLog#L326

2020.2

https://github.com/Xilinx/embeddedsw/

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blob/

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release-

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2020.2/

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doc/

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ChangeLog#L234

2020.1

Summary:

No

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functional changes

https://github.com/Xilinx/embeddedsw/blob/release-2020.1/doc/ChangeLog#L569

2019.2

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Commits:

https://github.com/Xilinx/embeddedsw/

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blob/

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release-

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2019.2/

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doc/

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761c9af Fixed trivial typos reported by codespell utility
a2c7c62 zdma: This patch fixes the coverity warnings for "Deadcode".
599653d zdma: This patch fixes the coverity warnings for "OVERFLOW_BEFORE_WIDEN"
c78886a zdma: This patch fixes the coverity warning for "Event result_independent_of_operands".
3088184 zdma: Updated the modification history for zdma.

2019.1
  • Minor enhancements and bugfixes

Commits:

ChangeLog#L93

2019.1

https://github.com/Xilinx/embeddedsw/

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blob/

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release-

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2019.1/

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cc2043c zdma: Fix data alignment in the examples for IAR compiler
2f2fc35 zdma: Fix peripheral app compilation issue with armclang compiler

doc/ChangeLog#L290

2018.3

  • Bugfixes and warning fixes

Commits:

da83a6d zdma: Fix cppcheck and coverity warnings
b4a4e8e zdma: Fix cpp check warning
60f5393 zdma: Resolve MISRA-C:2012 compliance mandatory violations
f406504 zdma: Use -hier option while using get_cells commandhttps://github.com/Xilinx/embeddedsw/blob/release-2018.3/doc/ChangeLog#L419

2018.2

None

2018.1

  • Added support for peripheral test app support

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  • Add support for peripheral test app support

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  • None

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  • Add support for CCI at EL1 NS
  • Updated examples for CCI support

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  • None

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  • Fixed compilation errors for IAR compiler
  • Added readme.txt file to generate doxygen for examples

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  • None

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  • None

https://github.com/Xilinx/embeddedsw/blob/release-2018.1/doc/ChangeLog#L287

Related Links

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