[PATCH net-next v3 5/7] net: ethtool: Add new power limit get and set features

[Kory Maincent <kory.maincent@bootlin.com>]

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

This patch expands the status information provided by ethtool for PSE c33
with power limit. It also adds a call to pse_ethtool_set_pw_limit() to
configure the PSE control power limit.

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

Change in v3:
- Add ethtool netlink documentation.
---
 Documentation/networking/ethtool-netlink.rst |  8 ++++++
 include/uapi/linux/ethtool_netlink.h         |  1 +
 net/ethtool/pse-pd.c                         | 42 +++++++++++++++++++++++-----
 3 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 7dbf2ef3ac0e..a78b6aea84af 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -1737,6 +1737,7 @@ Kernel response contents:
                                                   PoE PSE.
   ``ETHTOOL_A_C33_PSE_EXT_SUBSTATE``         u32  power extended substatus of
                                                   the PoE PSE.
+  ``ETHTOOL_A_C33_PSE_PW_LIMIT``             u32  power limit of the PoE PSE.
   ======================================  ======  =============================
 
 When set, the optional ``ETHTOOL_A_PODL_PSE_ADMIN_STATE`` attribute identifies
@@ -1799,6 +1800,9 @@ Possible values are:
 		  ethtool_c33_pse_ext_substate_power_not_available
 		  ethtool_c33_pse_ext_substate_short_detected
 
+When set, the optional ``ETHTOOL_A_C33_PSE_PW_LIMIT`` attribute identifies
+the C33 PSE power limit in mW.
+
 PSE_SET
 =======
 
@@ -1810,6 +1814,7 @@ Request contents:
   ``ETHTOOL_A_PSE_HEADER``                nested  request header
   ``ETHTOOL_A_PODL_PSE_ADMIN_CONTROL``       u32  Control PoDL PSE Admin state
   ``ETHTOOL_A_C33_PSE_ADMIN_CONTROL``        u32  Control PSE Admin state
+  ``ETHTOOL_A_C33_PSE_PW_LIMIT``             u32  Control PoE PSE power limit
   ======================================  ======  =============================
 
 When set, the optional ``ETHTOOL_A_PODL_PSE_ADMIN_CONTROL`` attribute is used
@@ -1820,6 +1825,9 @@ to control PoDL PSE Admin functions. This option is implementing
 The same goes for ``ETHTOOL_A_C33_PSE_ADMIN_CONTROL`` implementing
 ``IEEE 802.3-2022`` 30.9.1.2.1 acPSEAdminControl.
 
+When set, the optional ``ETHTOOL_A_C33_PSE_PW_LIMIT`` attribute is used
+to control C33 PSE power limit in mW.
+
 RSS_GET
 =======
 
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 398a0aa8daad..62ac9e1001bf 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -919,6 +919,7 @@ enum {
 	ETHTOOL_A_C33_PSE_ACTUAL_PW,		/* u32 */
 	ETHTOOL_A_C33_PSE_EXT_STATE,		/* u32 */
 	ETHTOOL_A_C33_PSE_EXT_SUBSTATE,		/* u32 */
+	ETHTOOL_A_C33_PSE_PW_LIMIT,		/* u32 */
 
 	/* add new constants above here */
 	__ETHTOOL_A_PSE_CNT,
diff --git a/net/ethtool/pse-pd.c b/net/ethtool/pse-pd.c
index fec56db557d3..5c5eccd5b32b 100644
--- a/net/ethtool/pse-pd.c
+++ b/net/ethtool/pse-pd.c
@@ -94,6 +94,9 @@ static int pse_reply_size(const struct ethnl_req_info *req_base,
 		len += nla_total_size(sizeof(u32)); /* _C33_PSE_EXT_STATE */
 	if (st->c33_ext_state_info.__c33_pse_ext_substate > 0)
 		len += nla_total_size(sizeof(u32)); /* _C33_PSE_EXT_SUBSTATE */
+	if (st->c33_pw_limit > 0)
+		len += nla_total_size(sizeof(u32)); /* _C33_PSE_PW_LIMIT */
+
 	return len;
 }
 
@@ -144,6 +147,11 @@ static int pse_fill_reply(struct sk_buff *skb,
 			st->c33_ext_state_info.__c33_pse_ext_substate))
 		return -EMSGSIZE;
 
+	if (st->c33_pw_limit > 0 &&
+	    nla_put_u32(skb, ETHTOOL_A_C33_PSE_PW_LIMIT,
+			st->c33_pw_limit))
+		return -EMSGSIZE;
+
 	return 0;
 }
 
@@ -157,6 +165,7 @@ const struct nla_policy ethnl_pse_set_policy[ETHTOOL_A_PSE_MAX + 1] = {
 	[ETHTOOL_A_C33_PSE_ADMIN_CONTROL] =
 		NLA_POLICY_RANGE(NLA_U32, ETHTOOL_C33_PSE_ADMIN_STATE_DISABLED,
 				 ETHTOOL_C33_PSE_ADMIN_STATE_ENABLED),
+	[ETHTOOL_A_C33_PSE_PW_LIMIT] = { .type = NLA_U32 },
 };
 
 static int
@@ -199,19 +208,38 @@ static int
 ethnl_set_pse(struct ethnl_req_info *req_info, struct genl_info *info)
 {
 	struct net_device *dev = req_info->dev;
-	struct pse_control_config config = {};
 	struct nlattr **tb = info->attrs;
 	struct phy_device *phydev;
+	int ret = 0;
 
 	phydev = dev->phydev;
+
+	if (tb[ETHTOOL_A_C33_PSE_PW_LIMIT]) {
+		unsigned int pw_limit = nla_get_u32(tb[ETHTOOL_A_C33_PSE_PW_LIMIT]);
+
+		ret = pse_ethtool_set_pw_limit(phydev->psec, info->extack,
+					       pw_limit);
+		if (ret)
+			return ret;
+	}
+
 	/* These values are already validated by the ethnl_pse_set_policy */
-	if (pse_has_podl(phydev->psec))
-		config.podl_admin_control = nla_get_u32(tb[ETHTOOL_A_PODL_PSE_ADMIN_CONTROL]);
-	if (pse_has_c33(phydev->psec))
-		config.c33_admin_control = nla_get_u32(tb[ETHTOOL_A_C33_PSE_ADMIN_CONTROL]);
+	if (tb[ETHTOOL_A_PODL_PSE_ADMIN_CONTROL] ||
+	    tb[ETHTOOL_A_C33_PSE_ADMIN_CONTROL]) {
+		struct pse_control_config config = {};
+
+		if (pse_has_podl(phydev->psec))
+			config.podl_admin_control = nla_get_u32(tb[ETHTOOL_A_PODL_PSE_ADMIN_CONTROL]);
+		if (pse_has_c33(phydev->psec))
+			config.c33_admin_control = nla_get_u32(tb[ETHTOOL_A_C33_PSE_ADMIN_CONTROL]);
+
+		ret = pse_ethtool_set_config(phydev->psec, info->extack,
+					     &config);
+		if (ret)
+			return ret;
+	}
 
-	/* Return errno directly - PSE has no notification */
-	return pse_ethtool_set_config(phydev->psec, info->extack, &config);
+	return ret;
 }
 
 const struct ethnl_request_ops ethnl_pse_request_ops = {

-- 
2.34.1