linux-kernel - [PATCH ethtool v3 2/3] ethtool: pse-pd: Add PSE priority support

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Message-Id: <20250820-b4-feature_poe_pw_budget-v3-2-c3d57362c086@bootlin.com>
Date: Wed, 20 Aug 2025 11:07:33 +0200
From: Kory Maincent <kory.maincent@...tlin.com>
To: Oleksij Rempel <o.rempel@...gutronix.de>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Andrew Lunn <andrew@...n.ch>, Michal Kubecek <mkubecek@...e.cz>
Cc: Dent Project <dentproject@...uxfoundation.org>, 
 Kyle Swenson <kyle.swenson@....tech>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, netdev@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Kory Maincent <kory.maincent@...tlin.com>
Subject: [PATCH ethtool v3 2/3] ethtool: pse-pd: Add PSE priority support

From: Kory Maincent (Dent Project) <kory.maincent@...tlin.com>

Add support for PSE (Power Sourcing Equipment) priority management:
- Add priority configuration parameter (prio) for port priority management
- Display power domain index, maximum priority, and current priority

Signed-off-by: Kory Maincent <kory.maincent@...tlin.com>
---

Changes in v3:
- Improve doc thanks to Oleksij.
- Add a missing semicolon.
---
 ethtool.8.in     | 31 +++++++++++++++++++++++++++++++
 ethtool.c        |  1 +
 netlink/pse-pd.c | 29 +++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+)

diff --git a/ethtool.8.in b/ethtool.8.in
index 29b8a8c..553592b 100644
--- a/ethtool.8.in
+++ b/ethtool.8.in
@@ -561,6 +561,7 @@ ethtool \- query or control network driver and hardware settings
 .RB [ c33\-pse\-admin\-control
 .BR enable | disable ]
 .BN c33\-pse\-avail\-pw\-limit N
+.BN prio N
 .HP
 .B ethtool \-\-flash\-module\-firmware
 .I devname
@@ -1911,6 +1912,26 @@ This attribute specifies the allowed power limit ranges in mW for
 configuring the c33-pse-avail-pw-limit parameter. It defines the valid
 power levels that can be assigned to the c33 PSE in compliance with the
 c33 standard.
+.TP
+.B power-domain-index
+Reports the index of the PSE power domain the port belongs to. Every
+port belongs to exactly one power domain. Port priorities are defined
+within that power domain.
+
+Each power domain may have its own maximum budget (e.g., 100 W per
+domain) in addition to a system-wide budget (e.g., 200 W overall).
+Domain limits are enforced first: if a single domain reaches its budget,
+only ports in that domain are affected. The system-wide budget is
+enforced across all domains.
+.TP
+.B priority-max
+Reports the maximum configurable port priority value within the reported
+power domain. The valid range for prio is 0 to priority-max (inclusive).
+.TP
+.B priority
+Reports the currently configured port priority within the reported power
+domain. Lower numeric values indicate higher priority: 0 is the highest
+priority.
 
 .RE
 .TP
@@ -1930,6 +1951,16 @@ This parameter manages c33 PSE Admin operations in accordance with the IEEE
 This parameter manages c33 PSE Available Power Limit in mW, in accordance
 with the IEEE 802.3-2022 33.2.4.4 Variables (pse_available_power)
 specification.
+.TP
+.B prio \ N
+Set the port priority, scoped to the port's power domain
+as reported by power-domain-index. Lower values indicate higher
+priority; 0 is the highest. The valid range is 0 to the
+priority-max reported by --show-pse.
+
+When a single domain exceeds its budget, ports in that domain are
+powered up/down by priority (highest first for power-up; lowest shed
+first).
 
 .RE
 .TP
diff --git a/ethtool.c b/ethtool.c
index 215f566..948d551 100644
--- a/ethtool.c
+++ b/ethtool.c
@@ -6339,6 +6339,7 @@ static const struct option args[] = {
 		.xhelp	= "		[ podl-pse-admin-control enable|disable ]\n"
 			  "		[ c33-pse-admin-control enable|disable ]\n"
 			  "		[ c33-pse-avail-pw-limit N ]\n"
+			  "		[ prio N ]\n"
 	},
 	{
 		.opts	= "--flash-module-firmware",
diff --git a/netlink/pse-pd.c b/netlink/pse-pd.c
index fd1fc4d..f761871 100644
--- a/netlink/pse-pd.c
+++ b/netlink/pse-pd.c
@@ -420,6 +420,29 @@ int pse_reply_cb(const struct nlmsghdr *nlhdr, void *data)
 		}
 	}
 
+	if (tb[ETHTOOL_A_PSE_PW_D_ID]) {
+		u32 val;
+
+		val = mnl_attr_get_u32(tb[ETHTOOL_A_PSE_PW_D_ID]);
+		print_uint(PRINT_ANY, "power-domain-index",
+			   "Power domain index: %u\n", val);
+	}
+
+	if (tb[ETHTOOL_A_PSE_PRIO_MAX]) {
+		u32 val;
+
+		val = mnl_attr_get_u32(tb[ETHTOOL_A_PSE_PRIO_MAX]);
+		print_uint(PRINT_ANY, "priority-max",
+			   "Max allowed priority: %u\n", val);
+	}
+
+	if (tb[ETHTOOL_A_PSE_PRIO]) {
+		u32 val;
+
+		val = mnl_attr_get_u32(tb[ETHTOOL_A_PSE_PRIO]);
+		print_uint(PRINT_ANY, "priority", "Priority: %u\n", val);
+	}
+
 	close_json_object();
 
 	return MNL_CB_OK;
@@ -487,6 +510,12 @@ static const struct param_parser spse_params[] = {
 		.handler	= nl_parse_direct_u32,
 		.min_argc	= 1,
 	},
+	{
+		.arg		= "prio",
+		.type		= ETHTOOL_A_PSE_PRIO,
+		.handler	= nl_parse_direct_u32,
+		.min_argc	= 1,
+	},
 	{}
 };
 

-- 
2.43.0