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| 1 | +The QorIQ DPAA Ethernet Driver |
| 2 | +============================== |
| 3 | + |
| 4 | +Authors: |
| 5 | + |
| 6 | + |
| 7 | + |
| 8 | +Contents |
| 9 | +======== |
| 10 | + |
| 11 | + - DPAA Ethernet Overview |
| 12 | + - DPAA Ethernet Supported SoCs |
| 13 | + - Configuring DPAA Ethernet in your kernel |
| 14 | + - DPAA Ethernet Frame Processing |
| 15 | + - DPAA Ethernet Features |
| 16 | + - Debugging |
| 17 | + |
| 18 | +DPAA Ethernet Overview |
| 19 | +====================== |
| 20 | + |
| 21 | +DPAA stands for Data Path Acceleration Architecture and it is a |
| 22 | +set of networking acceleration IPs that are available on several |
| 23 | +generations of SoCs, both on PowerPC and ARM64. |
| 24 | + |
| 25 | +The Freescale DPAA architecture consists of a series of hardware blocks |
| 26 | +that support Ethernet connectivity. The Ethernet driver depends upon the |
| 27 | +following drivers in the Linux kernel: |
| 28 | + |
| 29 | + - Peripheral Access Memory Unit (PAMU) (* needed only for PPC platforms) |
| 30 | + drivers/iommu/fsl_* |
| 31 | + - Frame Manager (FMan) |
| 32 | + drivers/net/ethernet/freescale/fman |
| 33 | + - Queue Manager (QMan), Buffer Manager (BMan) |
| 34 | + drivers/soc/fsl/qbman |
| 35 | + |
| 36 | +A simplified view of the dpaa_eth interfaces mapped to FMan MACs: |
| 37 | + |
| 38 | + dpaa_eth /eth0\ ... /ethN\ |
| 39 | + driver | | | | |
| 40 | + ------------- ---- ----------- ---- ------------- |
| 41 | + -Ports / Tx Rx \ ... / Tx Rx \ |
| 42 | + FMan | | | | |
| 43 | + -MACs | MAC0 | | MACN | |
| 44 | + / dtsec0 \ ... / dtsecN \ (or tgec) |
| 45 | + / \ / \(or memac) |
| 46 | + --------- -------------- --- -------------- --------- |
| 47 | + FMan, FMan Port, FMan SP, FMan MURAM drivers |
| 48 | + --------------------------------------------------------- |
| 49 | + FMan HW blocks: MURAM, MACs, Ports, SP |
| 50 | + --------------------------------------------------------- |
| 51 | + |
| 52 | +The dpaa_eth relation to the QMan, BMan and FMan: |
| 53 | + ________________________________ |
| 54 | + dpaa_eth / eth0 \ |
| 55 | + driver / \ |
| 56 | + --------- -^- -^- -^- --- --------- |
| 57 | + QMan driver / \ / \ / \ \ / | BMan | |
| 58 | + |Rx | |Rx | |Tx | |Tx | | driver | |
| 59 | + --------- |Dfl| |Err| |Cnf| |FQs| | | |
| 60 | + QMan HW |FQ | |FQ | |FQs| | | | | |
| 61 | + / \ / \ / \ \ / | | |
| 62 | + --------- --- --- --- -v- --------- |
| 63 | + | FMan QMI | | |
| 64 | + | FMan HW FMan BMI | BMan HW | |
| 65 | + ----------------------- -------- |
| 66 | + |
| 67 | +where the acronyms used above (and in the code) are: |
| 68 | +DPAA = Data Path Acceleration Architecture |
| 69 | +FMan = DPAA Frame Manager |
| 70 | +QMan = DPAA Queue Manager |
| 71 | +BMan = DPAA Buffers Manager |
| 72 | +QMI = QMan interface in FMan |
| 73 | +BMI = BMan interface in FMan |
| 74 | +FMan SP = FMan Storage Profiles |
| 75 | +MURAM = Multi-user RAM in FMan |
| 76 | +FQ = QMan Frame Queue |
| 77 | +Rx Dfl FQ = default reception FQ |
| 78 | +Rx Err FQ = Rx error frames FQ |
| 79 | +Tx Cnf FQ = Tx confirmation FQs |
| 80 | +Tx FQs = transmission frame queues |
| 81 | +dtsec = datapath three speed Ethernet controller (10/100/1000 Mbps) |
| 82 | +tgec = ten gigabit Ethernet controller (10 Gbps) |
| 83 | +memac = multirate Ethernet MAC (10/100/1000/10000) |
| 84 | + |
| 85 | +DPAA Ethernet Supported SoCs |
| 86 | +============================ |
| 87 | + |
| 88 | +The DPAA drivers enable the Ethernet controllers present on the following SoCs: |
| 89 | + |
| 90 | +# PPC |
| 91 | +P1023 |
| 92 | +P2041 |
| 93 | +P3041 |
| 94 | +P4080 |
| 95 | +P5020 |
| 96 | +P5040 |
| 97 | +T1023 |
| 98 | +T1024 |
| 99 | +T1040 |
| 100 | +T1042 |
| 101 | +T2080 |
| 102 | +T4240 |
| 103 | +B4860 |
| 104 | + |
| 105 | +# ARM |
| 106 | +LS1043A |
| 107 | +LS1046A |
| 108 | + |
| 109 | +Configuring DPAA Ethernet in your kernel |
| 110 | +======================================== |
| 111 | + |
| 112 | +To enable the DPAA Ethernet driver, the following Kconfig options are required: |
| 113 | + |
| 114 | +# common for arch/arm64 and arch/powerpc platforms |
| 115 | +CONFIG_FSL_DPAA=y |
| 116 | +CONFIG_FSL_FMAN=y |
| 117 | +CONFIG_FSL_DPAA_ETH=y |
| 118 | +CONFIG_FSL_XGMAC_MDIO=y |
| 119 | + |
| 120 | +# for arch/powerpc only |
| 121 | +CONFIG_FSL_PAMU=y |
| 122 | + |
| 123 | +# common options needed for the PHYs used on the RDBs |
| 124 | +CONFIG_VITESSE_PHY=y |
| 125 | +CONFIG_REALTEK_PHY=y |
| 126 | +CONFIG_AQUANTIA_PHY=y |
| 127 | + |
| 128 | +DPAA Ethernet Frame Processing |
| 129 | +============================== |
| 130 | + |
| 131 | +On Rx, buffers for the incoming frames are retrieved from one of the three |
| 132 | +existing buffers pools. The driver initializes and seeds these, each with |
| 133 | +buffers of different sizes: 1KB, 2KB and 4KB. |
| 134 | + |
| 135 | +On Tx, all transmitted frames are returned to the driver through Tx |
| 136 | +confirmation frame queues. The driver is then responsible for freeing the |
| 137 | +buffers. In order to do this properly, a backpointer is added to the buffer |
| 138 | +before transmission that points to the skb. When the buffer returns to the |
| 139 | +driver on a confirmation FQ, the skb can be correctly consumed. |
| 140 | + |
| 141 | +DPAA Ethernet Features |
| 142 | +====================== |
| 143 | + |
| 144 | +Currently the DPAA Ethernet driver enables the basic features required for |
| 145 | +a Linux Ethernet driver. The support for advanced features will be added |
| 146 | +gradually. |
| 147 | + |
| 148 | +The driver has Rx and Tx checksum offloading for UDP and TCP. Currently the Rx |
| 149 | +checksum offload feature is enabled by default and cannot be controlled through |
| 150 | +ethtool. |
| 151 | + |
| 152 | +The driver has support for multiple prioritized Tx traffic classes. Priorities |
| 153 | +range from 0 (lowest) to 3 (highest). These are mapped to HW workqueues with |
| 154 | +strict priority levels. Each traffic class contains NR_CPU TX queues. By |
| 155 | +default, only one traffic class is enabled and the lowest priority Tx queues |
| 156 | +are used. Higher priority traffic classes can be enabled with the mqprio |
| 157 | +qdisc. For example, all four traffic classes are enabled on an interface with |
| 158 | +the following command. Furthermore, skb priority levels are mapped to traffic |
| 159 | +classes as follows: |
| 160 | + |
| 161 | + * priorities 0 to 3 - traffic class 0 (low priority) |
| 162 | + * priorities 4 to 7 - traffic class 1 (medium-low priority) |
| 163 | + * priorities 8 to 11 - traffic class 2 (medium-high priority) |
| 164 | + * priorities 12 to 15 - traffic class 3 (high priority) |
| 165 | + |
| 166 | +tc qdisc add dev <int> root handle 1: \ |
| 167 | + mqprio num_tc 4 map 0 0 0 0 1 1 1 1 2 2 2 2 3 3 3 3 hw 1 |
| 168 | + |
| 169 | +Debugging |
| 170 | +========= |
| 171 | + |
| 172 | +The following statistics are exported for each interface through ethtool: |
| 173 | + |
| 174 | + - interrupt count per CPU |
| 175 | + - Rx packets count per CPU |
| 176 | + - Tx packets count per CPU |
| 177 | + - Tx confirmed packets count per CPU |
| 178 | + - Tx S/G frames count per CPU |
| 179 | + - Tx error count per CPU |
| 180 | + - Rx error count per CPU |
| 181 | + - Rx error count per type |
| 182 | + - congestion related statistics: |
| 183 | + - congestion status |
| 184 | + - time spent in congestion |
| 185 | + - number of time the device entered congestion |
| 186 | + - dropped packets count per cause |
| 187 | + |
| 188 | +The driver also exports the following information in sysfs: |
| 189 | + |
| 190 | + - the FQ IDs for each FQ type |
| 191 | + /sys/devices/platform/dpaa-ethernet.0/net/<int>/fqids |
| 192 | + |
| 193 | + - the IDs of the buffer pools in use |
| 194 | + /sys/devices/platform/dpaa-ethernet.0/net/<int>/bpids |
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