Thread (38 messages) 38 messages, 6 authors, 2024-01-25

Re: [PATCH net-next v5 07/13] net: ethtool: Introduce a command to list PHYs on an interface

From: Jakub Kicinski <kuba@kernel.org>
Date: 2024-01-04 23:34:03
Also in: lkml, netdev

On Thu, 21 Dec 2023 19:00:40 +0100 Maxime Chevallier wrote:
As we have the ability to track the PHYs connected to a net_device
through the link_topology, we can expose this list to userspace. This
allows userspace to use these identifiers for phy-specific commands and
take the decision of which PHY to target by knowing the link topology.

Add PHY_GET and PHY_DUMP, which can be a filtered DUMP operation to list
devices on only one interface.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
quoted hunk ↗ jump to hunk
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 3ca6c21e74af..97ff787a7dd8 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -2011,6 +2011,49 @@ The attributes are propagated to the driver through the following structure:
 .. kernel-doc:: include/linux/ethtool.h
     :identifiers: ethtool_mm_cfg
 
+PHY_GET
+=======
+
+Retrieve information about a given Ethernet PHY sitting on the link. As there
+can be more than one PHY, the DUMP operation can be used to list the PHYs
+present on a given interface, by passing an interface index or name in
+the dump request
+
+Request contents:
+
+  ====================================  ======  ==========================
+  ``ETHTOOL_A_PHY_HEADER``              nested  request header
+  ====================================  ======  ==========================
+
+Kernel response contents:
+
+  ===================================== ======  ==========================
+  ``ETHTOOL_A_PHY_HEADER``              nested  request header
+  ``ETHTOOL_A_PHY_INDEX``               u32     the phy's unique index, that can
The fact that lines are longer than the ===== markings doesn't generate
warnings in htmldoc?
+                                                be used for phy-specific requests
+  ``ETHTOOL_A_PHY_DRVNAME``             string  the phy driver name
+  ``ETHTOOL_A_PHY_NAME``                string  the phy device name
+  ``ETHTOOL_A_PHY_UPSTREAM_TYPE``       u32     the type of device this phy is
+                                                connected to
+  ``ETHTOOL_A_PHY_UPSTREAM_PHY``        nested  if the phy is connected to another
+                                                phy, this nest contains info on
+                                                that connection
+  ``ETHTOOL_A_PHY_DOWNSTREAM_SFP_NAME`` string  if the phy controls an sfp bus,
+                                                the name of the sfp bus
Is upstream / downstream clear to everyone / from the spec.
I guess it's scoped to the netdev so upstream means "towards 
the netdev MAC"?
+  ``ETHTOOL_A_PHY_ID``                  u32     the phy id if the phy is C22
+  ===================================== ======  ==========================
+
+When ``ETHTOOL_A_PHY_UPSTREAM_TYPE`` is PHY_UPSTREAM_PHY, the PHY's parent is
+another PHY. Information on the parent PHY will be set in the
+``ETHTOOL_A_PHY_UPSTREAM_PHY`` nest, which has the following structure :
+
+  =================================== ======  ==========================
+  ``ETHTOOL_A_PHY_UPSTREAM_INDEX``    u32     the PHY index of the upstream PHY
+  ``ETHTOOL_A_PHY_UPSTREAM_SFP_NAME`` string  if this PHY is connected to it's
+                                                parent PHY through an SFP bus, the
+                                                name of this sfp bus
+  =================================== ======  ==========================
Why is this a nest?
 Request translation
 ===================
+enum {
+	ETHTOOL_A_PHY_UNSPEC,
+	ETHTOOL_A_PHY_HEADER,			/* nest - _A_HEADER_* */
+	ETHTOOL_A_PHY_INDEX,			/* u32 */
+	ETHTOOL_A_PHY_DRVNAME,			/* string */
+	ETHTOOL_A_PHY_NAME,			/* string */
+	ETHTOOL_A_PHY_UPSTREAM_TYPE,		/* u8 */
The Documentation say it's a u32 as it should be, AFAICT.
But code and some comments use u8.
+	ETHTOOL_A_PHY_UPSTREAM,			/* nest - _A_PHY_UPSTREAM_* */
+	ETHTOOL_A_PHY_DOWNSTREAM_SFP_NAME,	/* string */
+	ETHTOOL_A_PHY_ID,			/* u32 */
+
+	/* add new constants above here */
+	__ETHTOOL_A_PHY_CNT,
+	ETHTOOL_A_PHY_MAX = (__ETHTOOL_A_PHY_CNT - 1)
+};
quoted hunk ↗ jump to hunk
+++ b/net/ethtool/phy.c
@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2023 Bootlin
+ *
+ */
Do you really need 4 lines for the copyright? :)

+/* Caller holds rtnl */
+static ssize_t
+ethnl_phy_reply_size(const struct ethnl_req_info *req_base,
+		     struct netlink_ext_ack *extack)
+{
+	struct phy_link_topology *topo;
+	struct phy_device_node *pdn;
+	struct phy_device *phydev;
+	unsigned long index;
+	size_t size;
+
+	ASSERT_RTNL();
+
+	topo = &req_base->dev->link_topo;
+
+	size = nla_total_size(0);
no comment on this one?
+
+	xa_for_each(&topo->phys, index, pdn) {
Why count all the PHYs, you only output one on doit, right?
+		phydev = pdn->phy;
+
+		/* ETHTOOL_A_PHY_INDEX */
+		size += nla_total_size(sizeof(u32));
+
+		/* ETHTOOL_A_DRVNAME */
+		size += nla_total_size(strlen(phydev->drv->name) + 1);
+
+		/* ETHTOOL_A_NAME */
+		size += nla_total_size(strlen(dev_name(&phydev->mdio.dev)) + 1);
+
+		/* ETHTOOL_A_PHY_UPSTREAM_TYPE */
+		size += nla_total_size(sizeof(u8));
+
+		/* ETHTOOL_A_PHY_ID */
+		size += nla_total_size(sizeof(u32));
+
+		if (phy_on_sfp(phydev)) {
+			const char *upstream_sfp_name = sfp_get_name(pdn->parent_sfp_bus);
+
+			/* ETHTOOL_A_PHY_UPSTREAM_SFP_NAME */
+			if (upstream_sfp_name)
+				size += nla_total_size(strlen(upstream_sfp_name) + 1);
+
+			/* ETHTOOL_A_PHY_UPSTREAM_INDEX */
+			size += nla_total_size(sizeof(u32));
+		}
+
+		/* ETHTOOL_A_PHY_DOWNSTREAM_SFP_NAME */
+		if (phydev->sfp_bus) {
+			const char *sfp_name = sfp_get_name(phydev->sfp_bus);
+
+			if (sfp_name)
+				size += nla_total_size(strlen(sfp_name) + 1);
+		}
+	}
+
+	return size;
+}
+static int ethnl_phy_parse_request(struct ethnl_req_info *req_base,
+				   struct nlattr **tb)
+{
+	struct phy_link_topology *topo = &req_base->dev->link_topo;
+	struct phy_req_info *req_info = PHY_REQINFO(req_base);
+	struct phy_device_node *pdn;
+
+	if (!req_base->phydev)
+		return 0;
The PHY INDEX should probably be a required attr, with 
GENL_REQ_ATTR_CHECK()? Without phydev being specified
what's the point?
+	pdn = xa_load(&topo->phys, req_base->phydev->phyindex);
+	memcpy(&req_info->pdn, pdn, sizeof(*pdn));
+
+	return 0;
+}
+int ethnl_phy_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct ethnl_phy_dump_ctx *ctx = (void *)cb->ctx;
+	struct net *net = sock_net(skb->sk);
+	unsigned long ifindex = 1;
This doesn't look right, if dump gets full you gotta pick up
when previous call left off.
+	struct net_device *dev;
+	int ret = 0;
+
+	rtnl_lock();
+
+	if (ctx->phy_req_info->base.dev) {
+		ret = ethnl_phy_dump_one_dev(skb, ctx->phy_req_info->base.dev, cb);
+		ethnl_parse_header_dev_put(&ctx->phy_req_info->base);
+		ctx->phy_req_info->base.dev = NULL;
+	} else {
+		for_each_netdev_dump(net, dev, ifindex) {
+			ret = ethnl_phy_dump_one_dev(skb, dev, cb);
+			if (ret)
+				break;
+		}
+	}
+	rtnl_unlock();
+
+	if (ret == -EMSGSIZE && skb->len)
+		return skb->len;
+	return ret;
+}
+

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