linux项目工程资料-基于jz2440开发板的linux-4.9版本内核移植.zip

Copyright (C) 2015 Freescale Semiconductor Inc. DPAA2 (Data Path Acceleration Architecture Gen2) ------------------------------------------------ This document provides an overview of the Freescale DPAA2 architecture and how it is integrated into the Linux kernel. Contents summary -DPAA2 overview -Overview of DPAA2 objects -DPAA2 Linux driver architecture overview -bus driver -DPRC driver -allocator -DPIO driver -Ethernet -MAC DPAA2 Overview -------------- DPAA2 is a hardware architecture designed for high-speeed network packet processing. DPAA2 consists of sophisticated mechanisms for processing Ethernet packets, queue management, buffer management, autonomous L2 switching, virtual Ethernet bridging, and accelerator (e.g. crypto) sharing. A DPAA2 hardware component called the Management Complex (or MC) manages the DPAA2 hardware resources. The MC provides an object-based abstraction for software drivers to use the DPAA2 hardware. The MC uses DPAA2 hardware resources such as queues, buffer pools, and network ports to create functional objects/devices such as network interfaces, an L2 switch, or accelerator instances. The MC provides memory-mapped I/O command interfaces (MC portals) which DPAA2 software drivers use to operate on DPAA2 objects: The diagram below shows an overview of the DPAA2 resource management architecture: +--------------------------------------+ | OS | | DPAA2 drivers | | | | +-----------------------------|--------+ | | (create,discover,connect | config,use,destroy) | DPAA2 | +------------------------| mc portal |-+ | | | | +- - - - - - - - - - - - -V- - -+ | | | | | | | Management Complex (MC) | | | | | | | +- - - - - - - - - - - - - - - -+ | | | | Hardware Hardware | | Resources Objects | | --------- ------- | | -queues -DPRC | | -buffer pools -DPMCP | | -Eth MACs/ports -DPIO | | -network interface -DPNI | | profiles -DPMAC | | -queue portals -DPBP | | -MC portals ... | | ... | | | +--------------------------------------+ The MC mediates operations such as create, discover, connect, configuration, and destroy. Fast-path operations on data, such as packet transmit/receive, are not mediated by the MC and are done directly using memory mapped regions in DPIO objects. Overview of DPAA2 Objects ------------------------- The section provides a brief overview of some key DPAA2 objects. A simple scenario is described illustrating the objects involved in creating a network interfaces. -DPRC (Datapath Resource Container) A DPRC is a container object that holds all the other types of DPAA2 objects. In the example diagram below there are 8 objects of 5 types (DPMCP, DPIO, DPBP, DPNI, and DPMAC) in the container. +---------------------------------------------------------+ | DPRC | | | | +-------+ +-------+ +-------+ +-------+ +-------+ | | | DPMCP | | DPIO | | DPBP | | DPNI | | DPMAC | | | +-------+ +-------+ +-------+ +---+---+ +---+---+ | | | DPMCP | | DPIO | | | +-------+ +-------+ | | | DPMCP | | | +-------+ | | | +---------------------------------------------------------+ From the point of view of an OS, a DPRC behaves similar to a plug and play bus, like PCI. DPRC commands can be used to enumerate the contents of the DPRC, discover the hardware objects present (including mappable regions and interrupts). DPRC.1 (bus) | +--+--------+-------+-------+-------+ | | | | | DPMCP.1 DPIO.1 DPBP.1 DPNI.1 DPMAC.1 DPMCP.2 DPIO.2 DPMCP.3 Hardware objects can be created and destroyed dynamically, providing the ability to hot plug/unplug objects in and out of the DPRC. A DPRC has a mappable MMIO region (an MC portal) that can be used to send MC commands. It has an interrupt for status events (like hotplug). All objects in a container share the same hardware "isolation context". This means that with respect to an IOMMU the isolation granularity is at the DPRC (container) level, not at the individual object level. DPRCs can be defined statically and populated with objects via a config file passed to the MC when firmware starts it. There is also a Linux user space tool called "restool" that can be used to create/destroy containers and objects dynamically. -DPAA2 Objects for an Ethernet Network Interface A typical Ethernet NIC is monolithic-- the NIC device contains TX/RX queuing mechanisms, configuration mechanisms, buffer management, physical ports, and interrupts. DPAA2 uses a more granular approach utilizing multiple hardware objects. Each object provides specialized functions. Groups of these objects are used by software to provide Ethernet network interface functionality. This approach provides efficient use of finite hardware resources, flexibility, and performance advantages. The diagram below shows the objects needed for a simple network interface configuration on a system with 2 CPUs. +---+---+ +---+---+ CPU0 CPU1 +---+---+ +---+---+ | | +---+---+ +---+---+ DPIO DPIO +---+---+ +---+---+ \ / \ / \ / +---+---+ DPNI --- DPBP,DPMCP +---+---+ | | +---+---+ DPMAC +---+---+ | port/PHY Below the objects are described. For each object a brief description is provided along with a summary of the kinds of operations the object supports and a summary of key resources of the object (MMIO regions and IRQs). -DPMAC (Datapath Ethernet MAC): represents an Ethernet MAC, a hardware device that connects to an Ethernet PHY and allows physical transmission and reception of Ethernet frames. -MMIO regions: none -IRQs: DPNI link change -commands: set link up/down, link config, get stats, IRQ config, enable, reset -DPNI (Datapath Network Interface): contains TX/RX queues, network interface configuration, and RX buffer pool configuration mechanisms. The TX/RX queues are in memory and are identified by queue number. -MMIO regions: none -IRQs: link state -commands: port config, offload config, queue config, parse/classify config,