[PATCH v3 1/5] net: Introduce DSA class for Ethernet switches

Michael Walle
2021-01-22T21:30:48Z

Am 2021-01-22 20:16, schrieb Vladimir Oltean:
> From: Claudiu Manoil <claudiu.manoil@nxp.com>
>
> DSA stands for Distributed Switch Architecture and it covers switches
> that
> are connected to the CPU through an Ethernet link and generally use
> frame
> tags to pass information about the source/destination ports to/from
> CPU.
> Front panel ports are presented as regular ethernet devices in U-Boot
> and
> they are expected to support the typical networking commands.
> DSA switches may be cascaded, DSA class code does not currently support
> this.
>
> Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>
> Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
> Reviewed-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> ---
> v3:
> - Removed all infrastructure associated with dsa_foreach_port, which
> is no longer needed.
> - Only inherit the DSA master's MAC address if the environment does not
> already have a specific MAC address that should be used for the DSA
> port.
> - Be compatible with the new "ethernet-ports" container name which has
> been introduced in the Linux kernel as commit 85e05d263ed2 ("net:
> dsa:
> of: Allow ethernet-ports as encapsulating node") in v5.9.
>
> v2: none
>
> drivers/net/Kconfig | 14 ++
> include/dm/uclass-id.h | 1 +
> include/net.h | 6 +
> include/net/dsa.h | 163 ++++++++++++++
> net/Makefile | 1 +
> net/dsa-uclass.c | 470 +++++++++++++++++++++++++++++++++++++++++
> 6 files changed, 655 insertions(+)
> create mode 100644 include/net/dsa.h
> create mode 100644 net/dsa-uclass.c
>
> diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
> index 3a5e03688059..382224d04c6e 100644
> --- a/drivers/net/Kconfig
> +++ b/drivers/net/Kconfig
> @@ -37,6 +37,20 @@ config DM_MDIO_MUX
> This is currently implemented in net/mdio-mux-uclass.c
> Look in include/miiphy.h for details.
>
> +config DM_DSA
> + bool "Enable Driver Model for DSA switches"
> + depends on DM_ETH && DM_MDIO
> + help
> + Enable driver model for DSA switches
> +
> + Adds UCLASS_DSA class supporting switches that follow the
> Distributed
> + Switch Architecture (DSA). These switches rely on the presence of
> a
> + management switch port connected to an Ethernet controller capable
> of
> + receiving frames from the switch. This host Ethernet controller is
> + called the "master" Ethernet interface in DSA terminology.
> + This is currently implemented in net/dsa-uclass.c, refer to
> + include/net/dsa.h for API details.
> +
> config MDIO_SANDBOX
> depends on DM_MDIO && SANDBOX
> default y
> diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
> index ae4425d7a57a..d75de368c5a8 100644
> --- a/include/dm/uclass-id.h
> +++ b/include/dm/uclass-id.h
> @@ -46,6 +46,7 @@ enum uclass_id {
> UCLASS_DISPLAY, /* Display (e.g. DisplayPort, HDMI) */
> UCLASS_DSI_HOST, /* Display Serial Interface host */
> UCLASS_DMA, /* Direct Memory Access */
> + UCLASS_DSA, /* Distributed (Ethernet) Switch Architecture */
> UCLASS_EFI, /* EFI managed devices */
> UCLASS_ETH, /* Ethernet device */
> UCLASS_ETH_PHY, /* Ethernet PHY device */
> diff --git a/include/net.h b/include/net.h
> index 13da69b7c145..b95d6a6f60eb 100644
> --- a/include/net.h
> +++ b/include/net.h
> @@ -499,7 +499,13 @@ struct icmp_hdr {
> * maximum packet size and multiple of 32 bytes = 1536
> */
> #define PKTSIZE 1522
> +#ifndef CONFIG_DM_DSA
> #define PKTSIZE_ALIGN 1536
> +#else
> +/* Maximum DSA tagging overhead (headroom and/or tailroom) */
> +#define DSA_MAX_OVR 256
> +#define PKTSIZE_ALIGN (1536 + DSA_MAX_OVR)
> +#endif
>
> /*
> * Maximum receive ring size; that is, the number of packets
> diff --git a/include/net/dsa.h b/include/net/dsa.h
> new file mode 100644
> index 000000000000..18bc7ffbe470
> --- /dev/null
> +++ b/include/net/dsa.h
> @@ -0,0 +1,163 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright 2019-2021 NXP Semiconductors
> + */
> +
> +#ifndef __DSA_H__
> +#define __DSA_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_enable: Initialize a switch port for I/O.
> + * @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_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: DT node of the master Ethernet.
> + */
> +struct dsa_pdata {
> + int num_ports;
> + u32 cpu_port;
> + ofnode master_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_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__ */
> diff --git a/net/Makefile b/net/Makefile
> index 76527f704c47..fb3eba840fff 100644
> --- a/net/Makefile
> +++ b/net/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_NET) += arp.o
> obj-$(CONFIG_CMD_BOOTP) += bootp.o
> obj-$(CONFIG_CMD_CDP) += cdp.o
> obj-$(CONFIG_CMD_DNS) += dns.o
> +obj-$(CONFIG_DM_DSA) += dsa-uclass.o
> ifdef CONFIG_DM_ETH
> obj-$(CONFIG_NET) += eth-uclass.o
> else
> diff --git a/net/dsa-uclass.c b/net/dsa-uclass.c
> new file mode 100644
> index 000000000000..f60e06b00f57
> --- /dev/null
> +++ b/net/dsa-uclass.c
> @@ -0,0 +1,470 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2019-2021 NXP
> + */
> +
> +#include <net/dsa.h>
> +#include <dm/lists.h>
> +#include <dm/device_compat.h>
> +#include <dm/device-internal.h>
> +#include <dm/uclass-internal.h>
> +#include <linux/bitmap.h>
> +#include <miiphy.h>
> +
> +#define DSA_PORT_CHILD_DRV_NAME "dsa-port"
> +
> +/* per-device internal state structure */
> +struct dsa_priv {
> + struct udevice *master_dev;
> + int num_ports;
> + u32 cpu_port;
> + int headroom;
> + int tailroom;
> +};
> +
> +/* external API */
> +int dsa_set_tagging(struct udevice *dev, ushort headroom, ushort
> tailroom)
> +{
> + struct dsa_priv *priv;
> +
> + if (!dev || !dev_get_uclass_priv(dev))
> + return -ENODEV;
> +
> + if (headroom + tailroom > DSA_MAX_OVR)
> + return -EINVAL;
> +
> + priv = dev_get_uclass_priv(dev);
> +
> + if (headroom > 0)
> + priv->headroom = headroom;
> + if (tailroom > 0)
> + priv->tailroom = tailroom;
> +
> + return 0;
> +}
> +
> +/* returns the DSA master Ethernet device */
> +struct udevice *dsa_get_master(struct udevice *dev)
> +{
> + struct dsa_priv *priv = dev_get_uclass_priv(dev);
> +
> + if (!priv)
> + return NULL;
> +
> + return priv->master_dev;
> +}
> +
> +/*
> + * Start the desired port, the CPU port and the master Eth interface.
> + * TODO: if cascaded we may need to _start ports in other switches too
> + */
> +static int dsa_port_start(struct udevice *pdev)
> +{
> + struct udevice *dev = dev_get_parent(pdev);
> + struct dsa_priv *priv = dev_get_uclass_priv(dev);
> + struct udevice *master = dsa_get_master(dev);
> + struct dsa_ops *ops = dsa_get_ops(dev);
> + int err;
> +
> + if (!priv)
> + return -ENODEV;
> +
> + if (!master) {
> + dev_err(pdev, "DSA master Ethernet device not found!\n");
> + return -EINVAL;
> + }
> +
> + if (ops->port_enable) {
> + struct dsa_port_pdata *port_pdata;
> +
> + port_pdata = dev_get_parent_plat(pdev);
> + err = ops->port_enable(dev, port_pdata->index,
> + port_pdata->phy);
> + if (err)
> + return err;
> +
> + err = ops->port_enable(dev, priv->cpu_port, NULL);

This will lead to a NULL pointer dereference in felix_port_enable()
when accessing the phy. Although somehow (due to caching?) u-boot
won't panic until reaching board_phy_config() (the weak one in
drivers/net/phy/phy.c).

-michael

> + if (err)
> + return err;
> + }
> +
> + return eth_get_ops(master)->start(master);
> +}
> +
> +/* Stop the desired port, the CPU port and the master Eth interface */
> +static void dsa_port_stop(struct udevice *pdev)
> +{
> + struct udevice *dev = dev_get_parent(pdev);
> + struct dsa_priv *priv = dev_get_uclass_priv(dev);
> + struct udevice *master = dsa_get_master(dev);
> + struct dsa_ops *ops = dsa_get_ops(dev);
> +
> + if (!priv)
> + return;
> +
> + if (ops->port_disable) {
> + struct dsa_port_pdata *port_pdata;
> +
> + port_pdata = dev_get_parent_plat(pdev);
> + ops->port_disable(dev, port_pdata->index, port_pdata->phy);
> + ops->port_disable(dev, priv->cpu_port, NULL);
> + }
> +
> + /*
> + * stop master only if it's active, don't probe it otherwise.
> + * Under normal usage it would be active because we're using it, but
> + * during tear-down it may have been removed ahead of us.
> + */
> + if (master && device_active(master))
> + eth_get_ops(master)->stop(master);
> +}
> +
> +/*
> + * Insert a DSA tag and call master Ethernet send on the resulting
> packet
> + * We copy the frame to a stack buffer where we have reserved headroom
> and
> + * tailroom space. Headroom and tailroom are set to 0.
> + */
> +static int dsa_port_send(struct udevice *pdev, void *packet, int
> length)
> +{
> + struct udevice *dev = dev_get_parent(pdev);
> + struct dsa_priv *priv = dev_get_uclass_priv(dev);
> + int head = priv->headroom, tail = priv->tailroom;
> + struct udevice *master = dsa_get_master(dev);
> + struct dsa_ops *ops = dsa_get_ops(dev);
> + uchar dsa_packet_tmp[PKTSIZE_ALIGN];
> + struct dsa_port_pdata *port_pdata;
> + int err;
> +
> + if (!master)
> + return -EINVAL;
> +
> + if (length + head + tail > PKTSIZE_ALIGN)
> + return -EINVAL;
> +
> + memset(dsa_packet_tmp, 0, head);
> + memset(dsa_packet_tmp + head + length, 0, tail);
> + memcpy(dsa_packet_tmp + head, packet, length);
> + length += head + tail;
> + /* copy back to preserve original buffer alignment */
> + memcpy(packet, dsa_packet_tmp, length);
> +
> + port_pdata = dev_get_parent_plat(pdev);
> + err = ops->xmit(dev, port_pdata->index, packet, length);
> + if (err)
> + return err;
> +
> + return eth_get_ops(master)->send(master, packet, length);
> +}
> +
> +/* Receive a frame from master Ethernet, process it and pass it on */
> +static int dsa_port_recv(struct udevice *pdev, int flags, uchar
> **packetp)
> +{
> + struct udevice *dev = dev_get_parent(pdev);
> + struct dsa_priv *priv = dev_get_uclass_priv(dev);
> + int head = priv->headroom, tail = priv->tailroom;
> + struct udevice *master = dsa_get_master(dev);
> + struct dsa_ops *ops = dsa_get_ops(dev);
> + struct dsa_port_pdata *port_pdata;
> + int length, port_index, err;
> +
> + if (!master)
> + return -EINVAL;
> +
> + length = eth_get_ops(master)->recv(master, flags, packetp);
> + if (length <= 0)
> + return length;
> +
> + /*
> + * If we receive frames from a different port or frames that DSA
> driver
> + * doesn't like we discard them here.
> + * In case of discard we return with no frame and expect to be called
> + * again instead of looping here, so upper layer can deal with
> timeouts.
> + */
> + port_pdata = dev_get_parent_plat(pdev);
> + err = ops->rcv(dev, &port_index, *packetp, length);
> + if (err || port_index != port_pdata->index || (length <= head +
> tail)) {
> + if (eth_get_ops(master)->free_pkt)
> + eth_get_ops(master)->free_pkt(master, *packetp, length);
> + return -EAGAIN;
> + }
> +
> + /*
> + * We move the pointer over headroom here to avoid a copy. If
> free_pkt
> + * gets called we move the pointer back before calling master
> free_pkt.
> + */
> + *packetp += head;
> +
> + return length - head - tail;
> +}
> +
> +static int dsa_port_free_pkt(struct udevice *pdev, uchar *packet, int
> length)
> +{
> + struct udevice *dev = dev_get_parent(pdev);
> + struct udevice *master = dsa_get_master(dev);
> + struct dsa_priv *priv;
> +
> + if (!master)
> + return -EINVAL;
> +
> + priv = dev_get_uclass_priv(dev);
> + if (eth_get_ops(master)->free_pkt) {
> + /* return the original pointer and length to master Eth */
> + packet -= priv->headroom;
> + length += priv->headroom - priv->tailroom;
> +
> + return eth_get_ops(master)->free_pkt(master, packet, length);
> + }
> +
> + return 0;
> +}
> +
> +static int dsa_port_of_to_pdata(struct udevice *pdev)
> +{
> + struct dsa_port_pdata *port_pdata;
> + struct dsa_pdata *dsa_pdata;
> + struct eth_pdata *eth_pdata;
> + struct udevice *dev;
> + const char *label;
> + u32 index;
> + int err;
> +
> + if (!pdev)
> + return -ENODEV;
> +
> + err = ofnode_read_u32(dev_ofnode(pdev), "reg", &index);
> + if (err)
> + return err;
> +
> + dev = dev_get_parent(pdev);
> + dsa_pdata = dev_get_uclass_plat(dev);
> +
> + port_pdata = dev_get_parent_plat(pdev);
> + port_pdata->index = index;
> +
> + label = ofnode_read_string(dev_ofnode(pdev), "label");
> + if (label)
> + strncpy(port_pdata->name, label, DSA_PORT_NAME_LENGTH);
> +
> + eth_pdata = dev_get_plat(pdev);
> + eth_pdata->priv_pdata = port_pdata;
> +
> + dev_dbg(pdev, "port %d node %s\n", port_pdata->index,
> + ofnode_get_name(dev_ofnode(pdev)));
> +
> + return 0;
> +}
> +
> +static const struct eth_ops dsa_port_ops = {
> + .start = dsa_port_start,
> + .send = dsa_port_send,
> + .recv = dsa_port_recv,
> + .stop = dsa_port_stop,
> + .free_pkt = dsa_port_free_pkt,
> +};
> +
> +static int dsa_port_probe(struct udevice *pdev)
> +{
> + struct udevice *dev = dev_get_parent(pdev);
> + struct eth_pdata *eth_pdata, *master_pdata;
> + unsigned char env_enetaddr[ARP_HLEN];
> + struct dsa_port_pdata *port_pdata;
> + struct dsa_priv *dsa_priv;
> + struct udevice *master;
> +
> + port_pdata = dev_get_parent_plat(pdev);
> + dsa_priv = dev_get_uclass_priv(dev);
> +
> + port_pdata->phy = dm_eth_phy_connect(pdev);
> +
> + /*
> + * Inherit port's hwaddr from the DSA master, unless the port already
> + * has a unique MAC address specified in the environment.
> + */
> + eth_env_get_enetaddr_by_index("eth", dev_seq(pdev), env_enetaddr);
> + if (!is_zero_ethaddr(env_enetaddr))
> + return 0;
> +
> + master = dsa_get_master(dev);
> + if (!master)
> + return 0;
> +
> + master_pdata = dev_get_plat(master);
> + eth_pdata = dev_get_plat(pdev);
> + memcpy(eth_pdata->enetaddr, master_pdata->enetaddr, ARP_HLEN);
> + eth_env_set_enetaddr_by_index("eth", dev_seq(pdev),
> + master_pdata->enetaddr);
> +
> + return 0;
> +}
> +
> +static int dsa_port_remove(struct udevice *pdev)
> +{
> + struct udevice *dev = dev_get_parent(pdev);
> + struct dsa_port_pdata *port_pdata;
> + struct dsa_priv *dsa_priv;
> +
> + port_pdata = dev_get_parent_plat(pdev);
> + dsa_priv = dev_get_uclass_priv(dev);
> +
> + port_pdata->phy = NULL;
> +
> + return 0;
> +}
> +
> +U_BOOT_DRIVER(dsa_port) = {
> + .name = DSA_PORT_CHILD_DRV_NAME,
> + .id = UCLASS_ETH,
> + .ops = &dsa_port_ops,
> + .probe = dsa_port_probe,
> + .remove = dsa_port_remove,
> + .of_to_plat = dsa_port_of_to_pdata,
> + .plat_auto = sizeof(struct eth_pdata),
> +};
> +
> +/*
> + * This function mostly deals with pulling information out of the
> device tree
> + * into the pdata structure.
> + * It goes through the list of switch ports, registers an eth device
> for each
> + * front panel port and identifies the cpu port connected to master
> eth device.
> + * TODO: support cascaded switches
> + */
> +static int dsa_post_bind(struct udevice *dev)
> +{
> + struct dsa_pdata *pdata = dev_get_uclass_plat(dev);
> + ofnode node = dev_ofnode(dev), pnode;
> + int i, err, first_err = 0;
> +
> + if (!pdata || !ofnode_valid(node))
> + return -ENODEV;
> +
> + pdata->master_node = ofnode_null();
> +
> + node = ofnode_find_subnode(node, "ports");
> + if (!ofnode_valid(node))
> + node = ofnode_find_subnode(node, "ethernet-ports");
> + if (!ofnode_valid(node)) {
> + dev_err(dev, "ports node is missing under DSA device!\n");
> + return -EINVAL;
> + }
> +
> + pdata->num_ports = ofnode_get_child_count(node);
> + if (pdata->num_ports <= 0 || pdata->num_ports > DSA_MAX_PORTS) {
> + dev_err(dev, "invalid number of ports (%d)\n",
> + pdata->num_ports);
> + return -EINVAL;
> + }
> +
> + /* look for the CPU port */
> + ofnode_for_each_subnode(pnode, node) {
> + u32 ethernet;
> +
> + if (ofnode_read_u32(pnode, "ethernet", &ethernet))
> + continue;
> +
> + pdata->master_node = ofnode_get_by_phandle(ethernet);
> + break;
> + }
> +
> + if (!ofnode_valid(pdata->master_node)) {
> + dev_err(dev, "master eth node missing!\n");
> + return -EINVAL;
> + }
> +
> + if (ofnode_read_u32(pnode, "reg", &pdata->cpu_port)) {
> + dev_err(dev, "CPU port node not valid!\n");
> + return -EINVAL;
> + }
> +
> + dev_dbg(dev, "master node %s on port %d\n",
> + ofnode_get_name(pdata->master_node), pdata->cpu_port);
> +
> + for (i = 0; i < pdata->num_ports; i++) {
> + char name[DSA_PORT_NAME_LENGTH];
> + struct udevice *pdev;
> +
> + /*
> + * If this is the CPU port don't register it as an ETH device,
> + * we skip it on purpose since I/O to/from it from the CPU
> + * isn't useful
> + * TODO: cpu port may have a PHY and we don't handle that yet.
> + */
> + if (i == pdata->cpu_port)
> + continue;
> +
> + /*
> + * Set up default port names. If present, DT port labels
> + * will override the default port names.
> + */
> + snprintf(name, DSA_PORT_NAME_LENGTH, "%s@%d", dev->name, i);
> +
> + ofnode_for_each_subnode(pnode, node) {
> + u32 reg;
> +
> + if (ofnode_read_u32(pnode, "reg", &reg))
> + continue;
> +
> + if (reg == i)
> + break;
> + }
> +
> + /*
> + * skip registration if port id not found or if the port
> + * is explicitly disabled in DT
> + */
> + if (!ofnode_valid(pnode) || !ofnode_is_available(pnode))
> + continue;
> +
> + err = device_bind_driver_to_node(dev, DSA_PORT_CHILD_DRV_NAME,
> + name, pnode, &pdev);
> + if (pdev) {
> + struct dsa_port_pdata *port_pdata;
> +
> + port_pdata = dev_get_parent_plat(pdev);
> + strncpy(port_pdata->name, name, DSA_PORT_NAME_LENGTH);
> + pdev->name = port_pdata->name;
> + }
> +
> + /* try to bind all ports but keep 1st error */
> + if (err && !first_err)
> + first_err = err;
> + }
> +
> + if (first_err)
> + return first_err;
> +
> + dev_dbg(dev, "DSA ports successfully bound\n");
> +
> + return 0;
> +}
> +
> +/**
> + * Initialize the uclass per device internal state structure (priv).
> + * TODO: pick up references to other switch devices here, if we're
> cascaded.
> + */
> +static int dsa_pre_probe(struct udevice *dev)
> +{
> + struct dsa_pdata *pdata = dev_get_uclass_plat(dev);
> + struct dsa_priv *priv = dev_get_uclass_priv(dev);
> +
> + if (!pdata || !priv)
> + return -ENODEV;
> +
> + priv->num_ports = pdata->num_ports;
> + priv->cpu_port = pdata->cpu_port;
> +
> + if (ofnode_valid(pdata->master_node))
> + uclass_find_device_by_ofnode(UCLASS_ETH, pdata->master_node,
> + &priv->master_dev);
> + return 0;
> +}
> +
> +UCLASS_DRIVER(dsa) = {
> + .id = UCLASS_DSA,
> + .name = "dsa",
> + .post_bind = dsa_post_bind,
> + .pre_probe = dsa_pre_probe,
> + .per_device_auto = sizeof(struct dsa_priv),
> + .per_device_plat_auto = sizeof(struct dsa_pdata),
> + .per_child_plat_auto = sizeof(struct dsa_port_pdata),
> + .flags = DM_UC_FLAG_SEQ_ALIAS,
> +};

--
-michael