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diff --git a/drivers/staging/fsl-mc/README.txt b/drivers/staging/fsl-mc/README.txt deleted file mode 100644 index 524eda1de04f..000000000000 --- a/drivers/staging/fsl-mc/README.txt +++ /dev/null @@ -1,386 +0,0 @@ -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. - --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, IRQ config, enable, reset - - -DPIO (Datapath I/O): provides interfaces to enqueue and dequeue - packets and do hardware buffer pool management operations. The DPAA2 - architecture separates the mechanism to access queues (the DPIO object) - from the queues themselves. The DPIO provides an MMIO interface to - enqueue/dequeue packets. To enqueue something a descriptor is written - to the DPIO MMIO region, which includes the target queue number. - There will typically be one DPIO assigned to each CPU. This allows all - CPUs to simultaneously perform enqueue/dequeued operations. DPIOs are - expected to be shared by different DPAA2 drivers. - -MMIO regions: queue operations, buffer management - -IRQs: data availability, congestion notification, buffer - pool depletion - -commands: IRQ config, enable, reset - - -DPBP (Datapath Buffer Pool): represents a hardware buffer - pool. - -MMIO regions: none - -IRQs: none - -commands: enable, reset - - -DPMCP (Datapath MC Portal): provides an MC command portal. - Used by drivers to send commands to the MC to manage - objects. - -MMIO regions: MC command portal - -IRQs: command completion - -commands: IRQ config, enable, reset - - Object Connections - ------------------ - Some objects have explicit relationships that must - be configured: - - -DPNI <--> DPMAC - -DPNI <--> DPNI - -DPNI <--> L2-switch-port - A DPNI must be connected to something such as a DPMAC, - another DPNI, or L2 switch port. The DPNI connection - is made via a DPRC command. - - +-------+ +-------+ - | DPNI | | DPMAC | - +---+---+ +---+---+ - | | - +==========+ - - -DPNI <--> DPBP - A network interface requires a 'buffer pool' (DPBP - object) which provides a list of pointers to memory - where received Ethernet data is to be copied. The - Ethernet driver configures the DPBPs associated with - the network interface. - - Interrupts - ---------- - All interrupts generated by DPAA2 objects are message - interrupts. At the hardware level message interrupts - generated by devices will normally have 3 components-- - 1) a non-spoofable 'device-id' expressed on the hardware - bus, 2) an address, 3) a data value. - - In the case of DPAA2 devices/objects, all objects in the - same container/DPRC share the same 'device-id'. - For ARM-based SoC this is the same as the stream ID. - - -DPAA2 Linux Driver Overview ---------------------------- - -This section provides an overview of the Linux kernel drivers for -DPAA2-- 1) the bus driver and associated "DPAA2 infrastructure" -drivers and 2) functional object drivers (such as Ethernet). - -As described previously, a DPRC is a container that holds the other -types of DPAA2 objects. It is functionally similar to a plug-and-play -bus controller. - -Each object in the DPRC is a Linux "device" and is bound to a driver. -The diagram below shows the Linux drivers involved in a networking -scenario and the objects bound to each driver. A brief description -of each driver follows. - - +------------+ - | OS Network | - | Stack | - +------------+ +------------+ - | Allocator |. . . . . . . | Ethernet | - |(DPMCP,DPBP)| | (DPNI) | - +-.----------+ +---+---+----+ - . . ^ | - . . <data avail, | |<enqueue, - . . tx confirm> | | dequeue> - +-------------+ . | | - | DPRC driver | . +---+---V----+ +---------+ - | (DPRC) | . . . . . .| DPIO driver| | MAC | - +----------+--+ | (DPIO) | | (DPMAC) | - | +------+-----+ +-----+---+ - |<dev add/remove> | | - | | | - +----+--------------+ | +--+---+ - | MC-bus driver | | | PHY | - | | | |driver| - | /soc/fsl-mc | | +--+---+ - +-------------------+ | | - | | - ================================ HARDWARE =========|=================|====== - DPIO | - | | - DPNI---DPBP | - | | - DPMAC | - | | - PHY ---------------+ - ===================================================|======================== - -A brief description of each driver is provided below. - - MC-bus driver - ------------- - The MC-bus driver is a platform driver and is probed from a - node in the device tree (compatible "fsl,qoriq-mc") passed in by boot - firmware. It is responsible for bootstrapping the DPAA2 kernel - infrastructure. - Key functions include: - -registering a new bus type named "fsl-mc" with the kernel, - and implementing bus call-backs (e.g. match/uevent/dev_groups) - -implementing APIs for DPAA2 driver registration and for device - add/remove - -creates an MSI IRQ domain - -doing a 'device add' to expose the 'root' DPRC, in turn triggering - a bind of the root DPRC to the DPRC driver - The binding for the MC-bus device-tree node can be consulted here: - Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt - - DPRC driver - ----------- - The DPRC driver is bound to DPRC objects and does runtime management - of a bus instance. It performs the initial bus scan of the DPRC - and handles interrupts for container events such as hot plug by - re-scanning the DPRC. - - Allocator - ---------- - Certain objects such as DPMCP and DPBP are generic and fungible, - and are intended to be used by other drivers. For example, - the DPAA2 Ethernet driver needs: - -DPMCPs to send MC commands, to configure network interfaces - -DPBPs for network buffer pools - - The allocator driver registers for these allocatable object types - and those objects are bound to the allocator when the bus is probed. - The allocator maintains a pool of objects that are available for - allocation by other DPAA2 drivers. - - DPIO driver - ----------- - The DPIO driver is bound to DPIO objects and provides services that allow - other drivers such as the Ethernet driver to enqueue and dequeue data for - their respective objects. - Key services include: - -data availability notifications - -hardware queuing operations (enqueue and dequeue of data) - -hardware buffer pool management - - To transmit a packet the Ethernet driver puts data on a queue and - invokes a DPIO API. For receive, the Ethernet driver registers - a data availability notification callback. To dequeue a packet - a DPIO API is used. - - There is typically one DPIO object per physical CPU for optimum - performance, allowing different CPUs to simultaneously enqueue - and dequeue data. - - The DPIO driver operates on behalf of all DPAA2 drivers - active in the kernel-- Ethernet, crypto, compression, - etc. - - Ethernet - -------- - The Ethernet driver is bound to a DPNI and implements the kernel - interfaces needed to connect the DPAA2 network interface to - the network stack. - - Each DPNI corresponds to a Linux network interface. - - MAC driver - ---------- - An Ethernet PHY is an off-chip, board specific component and is managed - by the appropriate PHY driver via an mdio bus. The MAC driver - plays a role of being a proxy between the PHY driver and the - MC. It does this proxy via the MC commands to a DPMAC object. - If the PHY driver signals a link change, the MAC driver notifies - the MC via a DPMAC command. If a network interface is brought - up or down, the MC notifies the DPMAC driver via an interrupt and - the driver can take appropriate action. |