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