1.. include:: <isonum.txt> 2 3=================================== 4DPAA2 DPIO (Data Path I/O) Overview 5=================================== 6 7:Copyright: |copy| 2016-2018 NXP 8 9This document provides an overview of the Freescale DPAA2 DPIO 10drivers 11 12Introduction 13============ 14 15A DPAA2 DPIO (Data Path I/O) is a hardware object that provides 16interfaces to enqueue and dequeue frames to/from network interfaces 17and other accelerators. A DPIO also provides hardware buffer 18pool management for network interfaces. 19 20This document provides an overview the Linux DPIO driver, its 21subcomponents, and its APIs. 22 23See 24Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst 25for a general overview of DPAA2 and the general DPAA2 driver architecture 26in Linux. 27 28Driver Overview 29--------------- 30 31The DPIO driver is bound to DPIO objects discovered on the fsl-mc bus and 32provides services that: 33 34 A. allow other drivers, such as the Ethernet driver, to enqueue and dequeue 35 frames for their respective objects 36 B. allow drivers to register callbacks for data availability notifications 37 when data becomes available on a queue or channel 38 C. allow drivers to manage hardware buffer pools 39 40The Linux DPIO driver consists of 3 primary components-- 41 DPIO object driver-- fsl-mc driver that manages the DPIO object 42 43 DPIO service-- provides APIs to other Linux drivers for services 44 45 QBman portal interface-- sends portal commands, gets responses:: 46 47 fsl-mc other 48 bus drivers 49 | | 50 +---+----+ +------+-----+ 51 |DPIO obj| |DPIO service| 52 | driver |---| (DPIO) | 53 +--------+ +------+-----+ 54 | 55 +------+-----+ 56 | QBman | 57 | portal i/f | 58 +------------+ 59 | 60 hardware 61 62 63The diagram below shows how the DPIO driver components fit with the other 64DPAA2 Linux driver components:: 65 66 +------------+ 67 | OS Network | 68 | Stack | 69 +------------+ +------------+ 70 | Allocator |. . . . . . . | Ethernet | 71 |(DPMCP,DPBP)| | (DPNI) | 72 +-.----------+ +---+---+----+ 73 . . ^ | 74 . . <data avail, | |<enqueue, 75 . . tx confirm> | | dequeue> 76 +-------------+ . | | 77 | DPRC driver | . +--------+ +------------+ 78 | (DPRC) | . . |DPIO obj| |DPIO service| 79 +----------+--+ | driver |-| (DPIO) | 80 | +--------+ +------+-----+ 81 |<dev add/remove> +------|-----+ 82 | | QBman | 83 +----+--------------+ | portal i/f | 84 | MC-bus driver | +------------+ 85 | | | 86 | /soc/fsl-mc | | 87 +-------------------+ | 88 | 89 =========================================|=========|======================== 90 +-+--DPIO---|-----------+ 91 | | | 92 | QBman Portal | 93 +-----------------------+ 94 95 ============================================================================ 96 97 98DPIO Object Driver (dpio-driver.c) 99---------------------------------- 100 101 The dpio-driver component registers with the fsl-mc bus to handle objects of 102 type "dpio". The implementation of probe() handles basic initialization 103 of the DPIO including mapping of the DPIO regions (the QBman SW portal) 104 and initializing interrupts and registering irq handlers. The dpio-driver 105 registers the probed DPIO with dpio-service. 106 107DPIO service (dpio-service.c, dpaa2-io.h) 108------------------------------------------ 109 110 The dpio service component provides queuing, notification, and buffers 111 management services to DPAA2 drivers, such as the Ethernet driver. A system 112 will typically allocate 1 DPIO object per CPU to allow queuing operations 113 to happen simultaneously across all CPUs. 114 115 Notification handling 116 dpaa2_io_service_register() 117 118 dpaa2_io_service_deregister() 119 120 dpaa2_io_service_rearm() 121 122 Queuing 123 dpaa2_io_service_pull_fq() 124 125 dpaa2_io_service_pull_channel() 126 127 dpaa2_io_service_enqueue_fq() 128 129 dpaa2_io_service_enqueue_qd() 130 131 dpaa2_io_store_create() 132 133 dpaa2_io_store_destroy() 134 135 dpaa2_io_store_next() 136 137 Buffer pool management 138 dpaa2_io_service_release() 139 140 dpaa2_io_service_acquire() 141 142QBman portal interface (qbman-portal.c) 143--------------------------------------- 144 145 The qbman-portal component provides APIs to do the low level hardware 146 bit twiddling for operations such as: 147 148 - initializing Qman software portals 149 - building and sending portal commands 150 - portal interrupt configuration and processing 151 152 The qbman-portal APIs are not public to other drivers, and are 153 only used by dpio-service. 154 155Other (dpaa2-fd.h, dpaa2-global.h) 156---------------------------------- 157 158 Frame descriptor and scatter-gather definitions and the APIs used to 159 manipulate them are defined in dpaa2-fd.h. 160 161 Dequeue result struct and parsing APIs are defined in dpaa2-global.h. 162