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