net: ethtool: Add PSE port priority support feature

This patch expands the status information provided by ethtool for PSE c33
with current port priority and max port priority. It also adds a call to
pse_ethtool_set_prio() to configure the PSE port priority.

Signed-off-by: Kory Maincent (Dent Project) <kory.maincent@bootlin.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20250617-feature_poe_port_prio-v14-8-78a1a645e2ee@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/ethtool.yaml

@@ -1436,6 +1436,14 @@ attribute-sets:
         name: pse-pw-d-id
         type: u32
         name-prefix: ethtool-a-
+      -
+        name: pse-prio-max
+        type: u32
+        name-prefix: ethtool-a-
+      -
+        name: pse-prio
+        type: u32
+        name-prefix: ethtool-a-
   -
     name: rss
     attr-cnt-name: __ethtool-a-rss-cnt
@@ -2260,6 +2268,8 @@ operations:
             - c33-pse-avail-pw-limit
             - c33-pse-pw-limit-ranges
             - pse-pw-d-id
+            - pse-prio-max
+            - pse-prio
       dump: *pse-get-op
     -
       name: pse-set
@@ -2274,6 +2284,7 @@ operations:
             - podl-pse-admin-control
             - c33-pse-admin-control
             - c33-pse-avail-pw-limit
+            - pse-prio
     -
       name: rss-get
       doc: Get RSS params.

Documentation/networking/ethtool-netlink.rst

@@ -1790,6 +1790,10 @@ Kernel response contents:
   ``ETHTOOL_A_C33_PSE_PW_LIMIT_RANGES``       nested  Supported power limit
                                                       configuration ranges.
   ``ETHTOOL_A_PSE_PW_D_ID``                      u32  Index of the PSE power domain
+  ``ETHTOOL_A_PSE_PRIO_MAX``                     u32  Priority maximum configurable
+                                                      on the PoE PSE
+  ``ETHTOOL_A_PSE_PRIO``                         u32  Priority of the PoE PSE
+                                                      currently configured
   ==========================================  ======  =============================
 
 When set, the optional ``ETHTOOL_A_PODL_PSE_ADMIN_STATE`` attribute identifies
@@ -1866,6 +1870,12 @@ equal.
 The ``ETHTOOL_A_PSE_PW_D_ID`` attribute identifies the index of PSE power
 domain.
 
+When set, the optional ``ETHTOOL_A_PSE_PRIO_MAX`` attribute identifies
+the PSE maximum priority value.
+When set, the optional ``ETHTOOL_A_PSE_PRIO`` attributes is used to
+identifies the currently configured PSE priority.
+For a description of PSE priority attributes, see ``PSE_SET``.
+
 PSE_SET
 =======
 
@@ -1879,6 +1889,8 @@ Request contents:
   ``ETHTOOL_A_C33_PSE_ADMIN_CONTROL``        u32  Control PSE Admin state
   ``ETHTOOL_A_C33_PSE_AVAIL_PWR_LIMIT``      u32  Control PoE PSE available
                                                   power limit
+  ``ETHTOOL_A_PSE_PRIO``                     u32  Control priority of the
+                                                  PoE PSE
   ======================================  ======  =============================
 
 When set, the optional ``ETHTOOL_A_PODL_PSE_ADMIN_CONTROL`` attribute is used
@@ -1901,6 +1913,20 @@ various existing products that document power consumption in watts rather than
 classes. If power limit configuration based on classes is needed, the
 conversion can be done in user space, for example by ethtool.
 
+When set, the optional ``ETHTOOL_A_PSE_PRIO`` attributes is used to
+control the PSE priority. Allowed priority value are between zero and
+the value of ``ETHTOOL_A_PSE_PRIO_MAX`` attribute.
+
+A lower value indicates a higher priority, meaning that a priority value
+of 0 corresponds to the highest port priority.
+Port priority serves two functions:
+
+ - Power-up Order: After a reset, ports are powered up in order of their
+   priority from highest to lowest. Ports with higher priority
+   (lower values) power up first.
+ - Shutdown Order: When the power budget is exceeded, ports with lower
+   priority (higher values) are turned off first.
+
 PSE_NTF
 =======
 

include/uapi/linux/ethtool_netlink_generated.h

@@ -671,6 +671,8 @@ enum {
 	ETHTOOL_A_C33_PSE_AVAIL_PW_LIMIT,
 	ETHTOOL_A_C33_PSE_PW_LIMIT_RANGES,
 	ETHTOOL_A_PSE_PW_D_ID,
+	ETHTOOL_A_PSE_PRIO_MAX,
+	ETHTOOL_A_PSE_PRIO,
 
 	__ETHTOOL_A_PSE_CNT,
 	ETHTOOL_A_PSE_MAX = (__ETHTOOL_A_PSE_CNT - 1)

net/ethtool/pse-pd.c

@@ -111,6 +111,9 @@ static int pse_reply_size(const struct ethnl_req_info *req_base,
 		len += st->c33_pw_limit_nb_ranges *
 		       (nla_total_size(0) +
 			nla_total_size(sizeof(u32)) * 2);
+	if (st->prio_max)
+		/* _PSE_PRIO_MAX + _PSE_PRIO */
+		len += nla_total_size(sizeof(u32)) * 2;
 
 	return len;
 }
@@ -205,6 +208,11 @@ static int pse_fill_reply(struct sk_buff *skb,
 	    pse_put_pw_limit_ranges(skb, st))
 		return -EMSGSIZE;
 
+	if (st->prio_max &&
+	    (nla_put_u32(skb, ETHTOOL_A_PSE_PRIO_MAX, st->prio_max) ||
+	     nla_put_u32(skb, ETHTOOL_A_PSE_PRIO, st->prio)))
+		return -EMSGSIZE;
+
 	return 0;
 }
 
@@ -226,6 +234,7 @@ const struct nla_policy ethnl_pse_set_policy[ETHTOOL_A_PSE_MAX + 1] = {
 		NLA_POLICY_RANGE(NLA_U32, ETHTOOL_C33_PSE_ADMIN_STATE_DISABLED,
 				 ETHTOOL_C33_PSE_ADMIN_STATE_ENABLED),
 	[ETHTOOL_A_C33_PSE_AVAIL_PW_LIMIT] = { .type = NLA_U32 },
+	[ETHTOOL_A_PSE_PRIO] = { .type = NLA_U32 },
 };
 
 static int
@@ -274,6 +283,15 @@ ethnl_set_pse(struct ethnl_req_info *req_info, struct genl_info *info)
 	if (ret)
 		return ret;
 
+	if (tb[ETHTOOL_A_PSE_PRIO]) {
+		unsigned int prio;
+
+		prio = nla_get_u32(tb[ETHTOOL_A_PSE_PRIO]);
+		ret = pse_ethtool_set_prio(phydev->psec, info->extack, prio);
+		if (ret)
+			return ret;
+	}
+
 	if (tb[ETHTOOL_A_C33_PSE_AVAIL_PW_LIMIT]) {
 		unsigned int pw_limit;