1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * Copyright 2019-2021 NXP Semiconductors 4 */ 5 6 #ifndef __DSA_H__ 7 #define __DSA_H__ 8 9 #include <phy.h> 10 #include <net.h> 11 12 /** 13 * DSA stands for Distributed Switch Architecture and it is infrastructure 14 * intended to support drivers for Switches that rely on an intermediary 15 * Ethernet device for I/O. These switches may support cascading allowing 16 * them to be arranged as a tree. 17 * DSA is documented in detail in the Linux kernel documentation under 18 * Documentation/networking/dsa/dsa.txt 19 * The network layout of such a switch is shown below: 20 * 21 * |------| 22 * | eth0 | <--- master eth device (regular eth driver) 23 * |------| 24 * ^ | 25 * tag added by switch -->| | 26 * | | 27 * | |<-- tag added by DSA driver 28 * | v 29 * |--------------------------------------| 30 * | | CPU port | | <-- DSA (switch) device 31 * | ------------ | (DSA driver) 32 * | _________ _________ _________ | 33 * | | port0 | | port1 | ... | portn | | <-- ports as eth devices 34 * |-+-------+--+-------+-------+-------+-| ('dsa-port' eth driver) 35 * 36 * In U-Boot the intent is to allow access to front panel ports (shown at the 37 * bottom of the picture) through the master Ethernet dev (eth0 in the picture). 38 * Front panel ports are presented as regular Ethernet devices in U-Boot and 39 * they are expected to support the typical networking commands. 40 * In general DSA switches require the use of tags, extra headers added both by 41 * software on Tx and by the switch on Rx. These tags carry at a minimum port 42 * information and switch information for cascaded set-ups. 43 * In U-Boot these tags are inserted and parsed by the DSA switch driver, the 44 * class code helps with headroom/tailroom for the extra headers. 45 * 46 * TODO: 47 * - handle switch cascading, for now U-Boot only supports stand-alone switches. 48 * - Add support to probe DSA switches connected to a MDIO bus, this is needed 49 * to convert switch drivers that are now under drivers/net/phy. 50 */ 51 52 #define DSA_PORT_NAME_LENGTH 16 53 54 /* Maximum number of ports each DSA device can have */ 55 #define DSA_MAX_PORTS 12 56 57 /** 58 * struct dsa_ops - DSA operations 59 * 60 * @port_enable: Initialize a switch port for I/O. 61 * @port_disable: Disable I/O for a port. 62 * @xmit: Insert the DSA tag for transmission. 63 * DSA drivers receive a copy of the packet with headroom and 64 * tailroom reserved and set to 0. 'packet' points to headroom 65 * and 'length' is updated to include both head and tailroom. 66 * @rcv: Process the DSA tag on reception and return the port index 67 * from the h/w provided tag. Return the index via 'portp'. 68 * 'packet' and 'length' describe the frame as received from 69 * master including any additional headers. 70 */ 71 struct dsa_ops { 72 int (*port_enable)(struct udevice *dev, int port, 73 struct phy_device *phy); 74 void (*port_disable)(struct udevice *dev, int port, 75 struct phy_device *phy); 76 int (*xmit)(struct udevice *dev, int port, void *packet, int length); 77 int (*rcv)(struct udevice *dev, int *portp, void *packet, int length); 78 }; 79 80 #define dsa_get_ops(dev) ((struct dsa_ops *)(dev)->driver->ops) 81 82 /** 83 * struct dsa_port_pdata - DSA port platform data 84 * 85 * @phy: PHY device associated with this port. 86 * The uclass code attempts to set this field for all ports except CPU 87 * port, based on DT information. It may be NULL. 88 * @index: Port index in the DSA switch, set by the uclass code. 89 * @name: Name of the port Eth device. If a label property is present in the 90 * port DT node, it is used as name. 91 */ 92 struct dsa_port_pdata { 93 struct phy_device *phy; 94 u32 index; 95 char name[DSA_PORT_NAME_LENGTH]; 96 }; 97 98 /** 99 * struct dsa_pdata - Per-device platform data for DSA DM 100 * 101 * @num_ports: Number of ports the device has, must be <= DSA_MAX_PORTS. 102 * This number is extracted from the DT 'ports' node of this 103 * DSA device, and it counts the CPU port and all the other 104 * port subnodes including the disabled ones. 105 * @cpu_port: Index of the switch port linked to the master Ethernet. 106 * The uclass code sets this based on DT information. 107 * @master_node: OF node of the host Ethernet controller. 108 * @cpu_port_node: DT node of the switch's CPU port. 109 */ 110 struct dsa_pdata { 111 int num_ports; 112 u32 cpu_port; 113 ofnode master_node; 114 ofnode cpu_port_node; 115 }; 116 117 /** 118 * dsa_set_tagging() - Configure the headroom and/or tailroom sizes 119 * 120 * The DSA class code allocates headroom and tailroom on Tx before 121 * calling the DSA driver's xmit function. 122 * All drivers must call this at probe time. 123 * 124 * @dev: DSA device pointer 125 * @headroom: Size, in bytes, of headroom needed for the DSA tag. 126 * @tailroom: Size, in bytes, of tailroom needed for the DSA tag. 127 * Total headroom and tailroom size should not exceed 128 * DSA_MAX_OVR. 129 * @return 0 if OK, -ve on error 130 */ 131 int dsa_set_tagging(struct udevice *dev, ushort headroom, ushort tailroom); 132 133 /* DSA helpers */ 134 135 /** 136 * dsa_get_master() - Return a reference to the master Ethernet device 137 * 138 * Can be called at driver probe time or later. 139 * 140 * @dev: DSA device pointer 141 * @return Master Eth 'udevice' pointer if OK, NULL on error 142 */ 143 struct udevice *dsa_get_master(struct udevice *dev); 144 145 /** 146 * dsa_port_get_pdata() - Helper that returns the platdata of an active 147 * (non-CPU) DSA port device. 148 * 149 * Can be called at driver probe time or later. 150 * 151 * @pdev: DSA port device pointer 152 * @return 'dsa_port_pdata' pointer if OK, NULL on error 153 */ 154 static inline struct dsa_port_pdata * dsa_port_get_pdata(struct udevice * pdev)155 dsa_port_get_pdata(struct udevice *pdev) 156 { 157 struct eth_pdata *eth = dev_get_plat(pdev); 158 159 if (!eth) 160 return NULL; 161 162 return eth->priv_pdata; 163 } 164 165 #endif /* __DSA_H__ */ 166