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diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/dpio-driver.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/dpio-driver.rst new file mode 100644 index 000000000000..c50fd46631e0 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/dpio-driver.rst @@ -0,0 +1,160 @@ +.. include:: <isonum.txt> + +DPAA2 DPIO (Data Path I/O) Overview +=================================== + +:Copyright: |copy| 2016-2018 NXP + +This document provides an overview of the Freescale DPAA2 DPIO +drivers + +Introduction +============ + +A DPAA2 DPIO (Data Path I/O) is a hardware object that provides +interfaces to enqueue and dequeue frames to/from network interfaces +and other accelerators. A DPIO also provides hardware buffer +pool management for network interfaces. + +This document provides an overview the Linux DPIO driver, its +subcomponents, and its APIs. + +See +Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst +for a general overview of DPAA2 and the general DPAA2 driver architecture +in Linux. + +Driver Overview +--------------- + +The DPIO driver is bound to DPIO objects discovered on the fsl-mc bus and +provides services that: + + A. allow other drivers, such as the Ethernet driver, to enqueue and dequeue + frames for their respective objects + B. allow drivers to register callbacks for data availability notifications + when data becomes available on a queue or channel + C. allow drivers to manage hardware buffer pools + +The Linux DPIO driver consists of 3 primary components-- + DPIO object driver-- fsl-mc driver that manages the DPIO object + + DPIO service-- provides APIs to other Linux drivers for services + + QBman portal interface-- sends portal commands, gets responses:: + + fsl-mc other + bus drivers + | | + +---+----+ +------+-----+ + |DPIO obj| |DPIO service| + | driver |---| (DPIO) | + +--------+ +------+-----+ + | + +------+-----+ + | QBman | + | portal i/f | + +------------+ + | + hardware + + +The diagram below shows how the DPIO driver components fit with the other +DPAA2 Linux driver components:: + + +------------+ + | OS Network | + | Stack | + +------------+ +------------+ + | Allocator |. . . . . . . | Ethernet | + |(DPMCP,DPBP)| | (DPNI) | + +-.----------+ +---+---+----+ + . . ^ | + . . <data avail, | |<enqueue, + . . tx confirm> | | dequeue> + +-------------+ . | | + | DPRC driver | . +--------+ +------------+ + | (DPRC) | . . |DPIO obj| |DPIO service| + +----------+--+ | driver |-| (DPIO) | + | +--------+ +------+-----+ + |<dev add/remove> +------|-----+ + | | QBman | + +----+--------------+ | portal i/f | + | MC-bus driver | +------------+ + | | | + | /soc/fsl-mc | | + +-------------------+ | + | + =========================================|=========|======================== + +-+--DPIO---|-----------+ + | | | + | QBman Portal | + +-----------------------+ + + ============================================================================ + + +DPIO Object Driver (dpio-driver.c) +---------------------------------- + + The dpio-driver component registers with the fsl-mc bus to handle objects of + type "dpio". The implementation of probe() handles basic initialization + of the DPIO including mapping of the DPIO regions (the QBman SW portal) + and initializing interrupts and registering irq handlers. The dpio-driver + registers the probed DPIO with dpio-service. + +DPIO service (dpio-service.c, dpaa2-io.h) +------------------------------------------ + + The dpio service component provides queuing, notification, and buffers + management services to DPAA2 drivers, such as the Ethernet driver. A system + will typically allocate 1 DPIO object per CPU to allow queuing operations + to happen simultaneously across all CPUs. + + Notification handling + dpaa2_io_service_register() + + dpaa2_io_service_deregister() + + dpaa2_io_service_rearm() + + Queuing + dpaa2_io_service_pull_fq() + + dpaa2_io_service_pull_channel() + + dpaa2_io_service_enqueue_fq() + + dpaa2_io_service_enqueue_qd() + + dpaa2_io_store_create() + + dpaa2_io_store_destroy() + + dpaa2_io_store_next() + + Buffer pool management + dpaa2_io_service_release() + + dpaa2_io_service_acquire() + +QBman portal interface (qbman-portal.c) +--------------------------------------- + + The qbman-portal component provides APIs to do the low level hardware + bit twiddling for operations such as: + + - initializing Qman software portals + - building and sending portal commands + - portal interrupt configuration and processing + + The qbman-portal APIs are not public to other drivers, and are + only used by dpio-service. + +Other (dpaa2-fd.h, dpaa2-global.h) +---------------------------------- + + Frame descriptor and scatter-gather definitions and the APIs used to + manipulate them are defined in dpaa2-fd.h. + + Dequeue result struct and parsing APIs are defined in dpaa2-global.h. diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/ethernet-driver.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/ethernet-driver.rst new file mode 100644 index 000000000000..682f3986c15b --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/ethernet-driver.rst @@ -0,0 +1,186 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=============================== +DPAA2 Ethernet driver +=============================== + +:Copyright: |copy| 2017-2018 NXP + +This file provides documentation for the Freescale DPAA2 Ethernet driver. + +Supported Platforms +=================== +This driver provides networking support for Freescale DPAA2 SoCs, e.g. +LS2080A, LS2088A, LS1088A. + + +Architecture Overview +===================== +Unlike regular NICs, in the DPAA2 architecture there is no single hardware block +representing network interfaces; instead, several separate hardware resources +concur to provide the networking functionality: + +- network interfaces +- queues, channels +- buffer pools +- MAC/PHY + +All hardware resources are allocated and configured through the Management +Complex (MC) portals. MC abstracts most of these resources as DPAA2 objects +and exposes ABIs through which they can be configured and controlled. A few +hardware resources, like queues, do not have a corresponding MC object and +are treated as internal resources of other objects. + +For a more detailed description of the DPAA2 architecture and its object +abstractions see +*Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst*. + +Each Linux net device is built on top of a Datapath Network Interface (DPNI) +object and uses Buffer Pools (DPBPs), I/O Portals (DPIOs) and Concentrators +(DPCONs). + +Configuration interface:: + + ----------------------- + | DPAA2 Ethernet Driver | + ----------------------- + . . . + . . . + . . . . . . . . . . . . + . . . + . . . + ---------- ---------- ----------- + | DPBP API | | DPNI API | | DPCON API | + ---------- ---------- ----------- + . . . software + ======= . ========== . ============ . =================== + . . . hardware + ------------------------------------------ + | MC hardware portals | + ------------------------------------------ + . . . + . . . + ------ ------ ------- + | DPBP | | DPNI | | DPCON | + ------ ------ ------- + +The DPNIs are network interfaces without a direct one-on-one mapping to PHYs. +DPBPs represent hardware buffer pools. Packet I/O is performed in the context +of DPCON objects, using DPIO portals for managing and communicating with the +hardware resources. + +Datapath (I/O) interface:: + + ----------------------------------------------- + | DPAA2 Ethernet Driver | + ----------------------------------------------- + | ^ ^ | | + | | | | | + enqueue| dequeue| data | dequeue| seed | + (Tx) | (Rx, TxC)| avail.| request| buffers| + | | notify| | | + | | | | | + V | | V V + ----------------------------------------------- + | DPIO Driver | + ----------------------------------------------- + | | | | | software + | | | | | ================ + | | | | | hardware + ----------------------------------------------- + | I/O hardware portals | + ----------------------------------------------- + | ^ ^ | | + | | | | | + | | | V | + V | ================ V + ---------------------- | ------------- + queues ---------------------- | | Buffer pool | + ---------------------- | ------------- + ======================= + Channel + +Datapath I/O (DPIO) portals provide enqueue and dequeue services, data +availability notifications and buffer pool management. DPIOs are shared between +all DPAA2 objects (and implicitly all DPAA2 kernel drivers) that work with data +frames, but must be affine to the CPUs for the purpose of traffic distribution. + +Frames are transmitted and received through hardware frame queues, which can be +grouped in channels for the purpose of hardware scheduling. The Ethernet driver +enqueues TX frames on egress queues and after transmission is complete a TX +confirmation frame is sent back to the CPU. + +When frames are available on ingress queues, a data availability notification +is sent to the CPU; notifications are raised per channel, so even if multiple +queues in the same channel have available frames, only one notification is sent. +After a channel fires a notification, is must be explicitly rearmed. + +Each network interface can have multiple Rx, Tx and confirmation queues affined +to CPUs, and one channel (DPCON) for each CPU that services at least one queue. +DPCONs are used to distribute ingress traffic to different CPUs via the cores' +affine DPIOs. + +The role of hardware buffer pools is storage of ingress frame data. Each network +interface has a privately owned buffer pool which it seeds with kernel allocated +buffers. + + +DPNIs are decoupled from PHYs; a DPNI can be connected to a PHY through a DPMAC +object or to another DPNI through an internal link, but the connection is +managed by MC and completely transparent to the Ethernet driver. + +:: + + --------- --------- --------- + | eth if1 | | eth if2 | | eth ifn | + --------- --------- --------- + . . . + . . . + . . . + --------------------------- + | DPAA2 Ethernet Driver | + --------------------------- + . . . + . . . + . . . + ------ ------ ------ ------- + | DPNI | | DPNI | | DPNI | | DPMAC |----+ + ------ ------ ------ ------- | + | | | | | + | | | | ----- + =========== ================== | PHY | + ----- + +Creating a Network Interface +============================ +A net device is created for each DPNI object probed on the MC bus. Each DPNI has +a number of properties which determine the network interface configuration +options and associated hardware resources. + +DPNI objects (and the other DPAA2 objects needed for a network interface) can be +added to a container on the MC bus in one of two ways: statically, through a +Datapath Layout Binary file (DPL) that is parsed by MC at boot time; or created +dynamically at runtime, via the DPAA2 objects APIs. + + +Features & Offloads +=================== +Hardware checksum offloading is supported for TCP and UDP over IPv4/6 frames. +The checksum offloads can be independently configured on RX and TX through +ethtool. + +Hardware offload of unicast and multicast MAC filtering is supported on the +ingress path and permanently enabled. + +Scatter-gather frames are supported on both RX and TX paths. On TX, SG support +is configurable via ethtool; on RX it is always enabled. + +The DPAA2 hardware can process jumbo Ethernet frames of up to 10K bytes. + +The Ethernet driver defines a static flow hashing scheme that distributes +traffic based on a 5-tuple key: src IP, dst IP, IP proto, L4 src port, +L4 dst port. No user configuration is supported for now. + +Hardware specific statistics for the network interface as well as some +non-standard driver stats can be consulted through ethtool -S option. diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/index.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/index.rst new file mode 100644 index 000000000000..ee40fcc5ddff --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/index.rst @@ -0,0 +1,11 @@ +=================== +DPAA2 Documentation +=================== + +.. toctree:: + :maxdepth: 1 + + overview + dpio-driver + ethernet-driver + mac-phy-support diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst new file mode 100644 index 000000000000..51e6624fb774 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/mac-phy-support.rst @@ -0,0 +1,191 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +======================= +DPAA2 MAC / PHY support +======================= + +:Copyright: |copy| 2019 NXP + +Overview +-------- + +The DPAA2 MAC / PHY support consists of a set of APIs that help DPAA2 network +drivers (dpaa2-eth, dpaa2-ethsw) interract with the PHY library. + +DPAA2 Software Architecture +--------------------------- + +Among other DPAA2 objects, the fsl-mc bus exports DPNI objects (abstracting a +network interface) and DPMAC objects (abstracting a MAC). The dpaa2-eth driver +probes on the DPNI object and connects to and configures a DPMAC object with +the help of phylink. + +Data connections may be established between a DPNI and a DPMAC, or between two +DPNIs. Depending on the connection type, the netif_carrier_[on/off] is handled +directly by the dpaa2-eth driver or by phylink. + +.. code-block:: none + + Sources of abstracted link state information presented by the MC firmware + + +--------------------------------------+ + +------------+ +---------+ | xgmac_mdio | + | net_device | | phylink |--| +-----+ +-----+ +-----+ +-----+ | + +------------+ +---------+ | | PHY | | PHY | | PHY | | PHY | | + | | | +-----+ +-----+ +-----+ +-----+ | + +------------------------------------+ | External MDIO bus | + | dpaa2-eth | +--------------------------------------+ + +------------------------------------+ + | | Linux + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + | | MC firmware + | /| V + +----------+ / | +----------+ + | | / | | | + | | | | | | + | DPNI |<------| |<------| DPMAC | + | | | | | | + | | \ |<---+ | | + +----------+ \ | | +----------+ + \| | + | + +--------------------------------------+ + | MC firmware polling MAC PCS for link | + | +-----+ +-----+ +-----+ +-----+ | + | | PCS | | PCS | | PCS | | PCS | | + | +-----+ +-----+ +-----+ +-----+ | + | Internal MDIO bus | + +--------------------------------------+ + + +Depending on an MC firmware configuration setting, each MAC may be in one of two modes: + +- DPMAC_LINK_TYPE_FIXED: the link state management is handled exclusively by + the MC firmware by polling the MAC PCS. Without the need to register a + phylink instance, the dpaa2-eth driver will not bind to the connected dpmac + object at all. + +- DPMAC_LINK_TYPE_PHY: The MC firmware is left waiting for link state update + events, but those are in fact passed strictly between the dpaa2-mac (based on + phylink) and its attached net_device driver (dpaa2-eth, dpaa2-ethsw), + effectively bypassing the firmware. + +Implementation +-------------- + +At probe time or when a DPNI's endpoint is dynamically changed, the dpaa2-eth +is responsible to find out if the peer object is a DPMAC and if this is the +case, to integrate it with PHYLINK using the dpaa2_mac_connect() API, which +will do the following: + + - look up the device tree for PHYLINK-compatible of binding (phy-handle) + - will create a PHYLINK instance associated with the received net_device + - connect to the PHY using phylink_of_phy_connect() + +The following phylink_mac_ops callback are implemented: + + - .validate() will populate the supported linkmodes with the MAC capabilities + only when the phy_interface_t is RGMII_* (at the moment, this is the only + link type supported by the driver). + + - .mac_config() will configure the MAC in the new configuration using the + dpmac_set_link_state() MC firmware API. + + - .mac_link_up() / .mac_link_down() will update the MAC link using the same + API described above. + +At driver unbind() or when the DPNI object is disconnected from the DPMAC, the +dpaa2-eth driver calls dpaa2_mac_disconnect() which will, in turn, disconnect +from the PHY and destroy the PHYLINK instance. + +In case of a DPNI-DPMAC connection, an 'ip link set dev eth0 up' would start +the following sequence of operations: + +(1) phylink_start() called from .dev_open(). +(2) The .mac_config() and .mac_link_up() callbacks are called by PHYLINK. +(3) In order to configure the HW MAC, the MC Firmware API + dpmac_set_link_state() is called. +(4) The firmware will eventually setup the HW MAC in the new configuration. +(5) A netif_carrier_on() call is made directly from PHYLINK on the associated + net_device. +(6) The dpaa2-eth driver handles the LINK_STATE_CHANGE irq in order to + enable/disable Rx taildrop based on the pause frame settings. + +.. code-block:: none + + +---------+ +---------+ + | PHYLINK |-------------->| eth0 | + +---------+ (5) +---------+ + (1) ^ | + | | + | v (2) + +-----------------------------------+ + | dpaa2-eth | + +-----------------------------------+ + | ^ (6) + | | + v (3) | + +---------+---------------+---------+ + | DPMAC | | DPNI | + +---------+ +---------+ + | MC Firmware | + +-----------------------------------+ + | + | + v (4) + +-----------------------------------+ + | HW MAC | + +-----------------------------------+ + +In case of a DPNI-DPNI connection, a usual sequence of operations looks like +the following: + +(1) ip link set dev eth0 up +(2) The dpni_enable() MC API called on the associated fsl_mc_device. +(3) ip link set dev eth1 up +(4) The dpni_enable() MC API called on the associated fsl_mc_device. +(5) The LINK_STATE_CHANGED irq is received by both instances of the dpaa2-eth + driver because now the operational link state is up. +(6) The netif_carrier_on() is called on the exported net_device from + link_state_update(). + +.. code-block:: none + + +---------+ +---------+ + | eth0 | | eth1 | + +---------+ +---------+ + | ^ ^ | + | | | | + (1) v | (6) (6) | v (3) + +---------+ +---------+ + |dpaa2-eth| |dpaa2-eth| + +---------+ +---------+ + | ^ ^ | + | | | | + (2) v | (5) (5) | v (4) + +---------+---------------+---------+ + | DPNI | | DPNI | + +---------+ +---------+ + | MC Firmware | + +-----------------------------------+ + + +Exported API +------------ + +Any DPAA2 driver that drivers endpoints of DPMAC objects should service its +_EVENT_ENDPOINT_CHANGED irq and connect/disconnect from the associated DPMAC +when necessary using the below listed API:: + + - int dpaa2_mac_connect(struct dpaa2_mac *mac); + - void dpaa2_mac_disconnect(struct dpaa2_mac *mac); + +A phylink integration is necessary only when the partner DPMAC is not of TYPE_FIXED. +One can check for this condition using the below API:: + + - bool dpaa2_mac_is_type_fixed(struct fsl_mc_device *dpmac_dev,struct fsl_mc_io *mc_io); + +Before connection to a MAC, the caller must allocate and populate the +dpaa2_mac structure with the associated net_device, a pointer to the MC portal +to be used and the actual fsl_mc_device structure of the DPMAC. diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst new file mode 100644 index 000000000000..d638b5a8aadd --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst @@ -0,0 +1,405 @@ +.. include:: <isonum.txt> + +========================================================= +DPAA2 (Data Path Acceleration Architecture Gen2) Overview +========================================================= + +:Copyright: |copy| 2015 Freescale Semiconductor Inc. +:Copyright: |copy| 2018 NXP + +This document provides an overview of the Freescale DPAA2 architecture +and how it is integrated into the Linux kernel. + +Introduction +============ + +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 Drivers 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| + | /bus/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 at +*Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt*. +The sysfs bind/unbind interfaces for the MC-bus can be consulted at +*Documentation/ABI/testing/sysfs-bus-fsl-mc*. + +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 driver +--------------- +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. |