1. CNXK DMA Device Driver

The cnxk dmadev driver provides a poll-mode driver (PMD) for Marvell DPI DMA Hardware Accelerator block found in OCTEONTX2 and OCTEONTX3 family of SoCs. Each DMA queue is exposed as a VF function when SRIOV is enabled.

The block supports following modes of DMA transfers:

  1. Internal - DMA within SoC DRAM to DRAM

  2. Inbound - Host DRAM to SoC DRAM when SoC is in PCIe Endpoint

  3. Outbound - SoC DRAM to Host DRAM when SoC is in PCIe Endpoint

1.1. Prerequisites and Compilation procedure

See Marvell cnxk platform guide for setup information.

1.2. Device Setup

The dpdk-devbind.py script, included with DPDK, can be used to show the presence of supported hardware. Running dpdk-devbind.py --status-dev dma will show all the CNXK DMA devices.

1.2.1. Devices using VFIO drivers

The HW devices to be used will need to be bound to a user-space IO driver for use. The dpdk-devbind.py script can be used to view the state of the devices and to bind them to a suitable DPDK-supported driver, such as vfio-pci. For example:

$ dpdk-devbind.py -b vfio-pci 0000:05:00.1

1.2.2. Device Probing and Initialization

To use the devices from an application, the dmadev API can be used. CNXK DMA device configuration requirements:

  • Only one vchan is supported per device.

  • CNXK DMA devices do not support silent mode.

Once configured, the device can then be made ready for use by calling the rte_dma_start() API.

1.2.3. Performing Data Copies

Refer to the Enqueue / Dequeue APIs section of the dmadev library documentation for details on operation enqueue and submission API usage.