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1.. SPDX-License-Identifier: GPL-2.02 3===============================================4Marvell CN10K DMA packet interface (DPI) driver5===============================================6 7Overview8========9 10DPI is a DMA packet interface hardware block in Marvell's CN10K silicon.11DPI hardware comprises a physical function (PF), its virtual functions,12mailbox logic, and a set of DMA engines & DMA command queues.13 14DPI PF function is an administrative function which services the mailbox15requests from its VF functions and provisions DMA engine resources to16it's VF functions.17 18mrvl_cn10k_dpi.ko misc driver loads on DPI PF device and services the19mailbox commands submitted by the VF devices and accordingly initializes20the DMA engines and VF device's DMA command queues. Also, driver creates21/dev/mrvl-cn10k-dpi node to set DMA engine and PEM (PCIe interface) port22attributes like fifo length, molr, mps & mrrs.23 24DPI PF driver is just an administrative driver to setup its VF device's25queues and provisions the hardware resources, it cannot initiate any26DMA operations. Only VF devices are provisioned with DMA capabilities.27 28Driver location29===============30 31drivers/misc/mrvl_cn10k_dpi.c32 33Driver IOCTLs34=============35 36:c:macro::`DPI_MPS_MRRS_CFG`37ioctl that sets max payload size & max read request size parameters of38a pem port to which DMA engines are wired.39 40 41:c:macro::`DPI_ENGINE_CFG`42ioctl that sets DMA engine's fifo sizes & max outstanding load request43thresholds.44 45User space code example46=======================47 48DPI VF devices are probed and accessed from user space applications using49vfio-pci driver. Below is a sample dpi dma application to demonstrate on50how applications use mailbox and ioctl services from DPI PF kernel driver.51 52https://github.com/MarvellEmbeddedProcessors/dpi-sample-app53