166 lines
5.8 KiB
C
166 lines
5.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Copyright 2019-2021 NXP Semiconductors
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*/
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#ifndef __DSA_H__
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#define __DSA_H__
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#include <phy.h>
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#include <net.h>
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/**
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* DSA stands for Distributed Switch Architecture and it is infrastructure
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* intended to support drivers for Switches that rely on an intermediary
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* Ethernet device for I/O. These switches may support cascading allowing
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* them to be arranged as a tree.
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* DSA is documented in detail in the Linux kernel documentation under
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* Documentation/networking/dsa/dsa.txt
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* The network layout of such a switch is shown below:
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*
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* |------|
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* | eth0 | <--- master eth device (regular eth driver)
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* |------|
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* ^ |
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* tag added by switch -->| |
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* | |
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* | |<-- tag added by DSA driver
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* | v
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* |--------------------------------------|
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* | | CPU port | | <-- DSA (switch) device
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* | ------------ | (DSA driver)
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* | _________ _________ _________ |
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* | | port0 | | port1 | ... | portn | | <-- ports as eth devices
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* |-+-------+--+-------+-------+-------+-| ('dsa-port' eth driver)
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*
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* In U-Boot the intent is to allow access to front panel ports (shown at the
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* bottom of the picture) through the master Ethernet dev (eth0 in the picture).
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* Front panel ports are presented as regular Ethernet devices in U-Boot and
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* they are expected to support the typical networking commands.
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* In general DSA switches require the use of tags, extra headers added both by
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* software on Tx and by the switch on Rx. These tags carry at a minimum port
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* information and switch information for cascaded set-ups.
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* In U-Boot these tags are inserted and parsed by the DSA switch driver, the
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* class code helps with headroom/tailroom for the extra headers.
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*
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* TODO:
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* - handle switch cascading, for now U-Boot only supports stand-alone switches.
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* - Add support to probe DSA switches connected to a MDIO bus, this is needed
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* to convert switch drivers that are now under drivers/net/phy.
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*/
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#define DSA_PORT_NAME_LENGTH 16
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/* Maximum number of ports each DSA device can have */
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#define DSA_MAX_PORTS 12
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/**
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* struct dsa_ops - DSA operations
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*
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* @port_enable: Initialize a switch port for I/O.
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* @port_disable: Disable I/O for a port.
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* @xmit: Insert the DSA tag for transmission.
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* DSA drivers receive a copy of the packet with headroom and
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* tailroom reserved and set to 0. 'packet' points to headroom
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* and 'length' is updated to include both head and tailroom.
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* @rcv: Process the DSA tag on reception and return the port index
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* from the h/w provided tag. Return the index via 'portp'.
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* 'packet' and 'length' describe the frame as received from
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* master including any additional headers.
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*/
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struct dsa_ops {
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int (*port_enable)(struct udevice *dev, int port,
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struct phy_device *phy);
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void (*port_disable)(struct udevice *dev, int port,
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struct phy_device *phy);
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int (*xmit)(struct udevice *dev, int port, void *packet, int length);
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int (*rcv)(struct udevice *dev, int *portp, void *packet, int length);
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};
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#define dsa_get_ops(dev) ((struct dsa_ops *)(dev)->driver->ops)
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/**
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* struct dsa_port_pdata - DSA port platform data
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*
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* @phy: PHY device associated with this port.
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* The uclass code attempts to set this field for all ports except CPU
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* port, based on DT information. It may be NULL.
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* @index: Port index in the DSA switch, set by the uclass code.
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* @name: Name of the port Eth device. If a label property is present in the
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* port DT node, it is used as name.
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*/
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struct dsa_port_pdata {
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struct phy_device *phy;
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u32 index;
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char name[DSA_PORT_NAME_LENGTH];
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};
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/**
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* struct dsa_pdata - Per-device platform data for DSA DM
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*
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* @num_ports: Number of ports the device has, must be <= DSA_MAX_PORTS.
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* This number is extracted from the DT 'ports' node of this
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* DSA device, and it counts the CPU port and all the other
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* port subnodes including the disabled ones.
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* @cpu_port: Index of the switch port linked to the master Ethernet.
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* The uclass code sets this based on DT information.
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* @master_node: OF node of the host Ethernet controller.
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* @cpu_port_node: DT node of the switch's CPU port.
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*/
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struct dsa_pdata {
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int num_ports;
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u32 cpu_port;
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ofnode master_node;
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ofnode cpu_port_node;
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};
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/**
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* dsa_set_tagging() - Configure the headroom and/or tailroom sizes
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*
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* The DSA class code allocates headroom and tailroom on Tx before
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* calling the DSA driver's xmit function.
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* All drivers must call this at probe time.
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*
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* @dev: DSA device pointer
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* @headroom: Size, in bytes, of headroom needed for the DSA tag.
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* @tailroom: Size, in bytes, of tailroom needed for the DSA tag.
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* Total headroom and tailroom size should not exceed
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* DSA_MAX_OVR.
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* @return 0 if OK, -ve on error
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*/
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int dsa_set_tagging(struct udevice *dev, ushort headroom, ushort tailroom);
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/* DSA helpers */
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/**
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* dsa_get_master() - Return a reference to the master Ethernet device
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*
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* Can be called at driver probe time or later.
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*
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* @dev: DSA device pointer
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* @return Master Eth 'udevice' pointer if OK, NULL on error
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*/
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struct udevice *dsa_get_master(struct udevice *dev);
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/**
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* dsa_port_get_pdata() - Helper that returns the platdata of an active
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* (non-CPU) DSA port device.
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*
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* Can be called at driver probe time or later.
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*
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* @pdev: DSA port device pointer
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* @return 'dsa_port_pdata' pointer if OK, NULL on error
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*/
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static inline struct dsa_port_pdata *
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dsa_port_get_pdata(struct udevice *pdev)
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{
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struct eth_pdata *eth = dev_get_plat(pdev);
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if (!eth)
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return NULL;
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return eth->priv_pdata;
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}
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#endif /* __DSA_H__ */
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