net/ethtool: add netlink interface for the PLCA RS

Add support for configuring the PLCA Reconciliation Sublayer on
multi-drop PHYs that support IEEE802.3cg-2019 Clause 148 (e.g.,
10BASE-T1S). This patch adds the appropriate netlink interface
to ethtool.

Signed-off-by: Piergiorgio Beruto <piergiorgio.beruto@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 94 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 9e0a76fc7de9..d0da303f6634 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -802,12 +802,17 @@ int ethtool_virtdev_set_link_ksettings(struct net_device *dev,
 
 struct phy_device;
 struct phy_tdr_config;
+struct phy_plca_cfg;
+struct phy_plca_status;
 
 /**
  * struct ethtool_phy_ops - Optional PHY device options
  * @get_sset_count: Get number of strings that @get_strings will write.
  * @get_strings: Return a set of strings that describe the requested objects
  * @get_stats: Return extended statistics about the PHY device.
+ * @get_plca_cfg: Return PLCA configuration.
+ * @set_plca_cfg: Set PLCA configuration.
+ * @get_plca_status: Get PLCA configuration.
  * @start_cable_test: Start a cable test
  * @start_cable_test_tdr: Start a Time Domain Reflectometry cable test
  *
@@ -819,6 +824,13 @@ struct ethtool_phy_ops {
 	int (*get_strings)(struct phy_device *dev, u8 *data);
 	int (*get_stats)(struct phy_device *dev,
 			 struct ethtool_stats *stats, u64 *data);
+	int (*get_plca_cfg)(struct phy_device *dev,
+			    struct phy_plca_cfg *plca_cfg);
+	int (*set_plca_cfg)(struct phy_device *dev,
+			    const struct phy_plca_cfg *plca_cfg,
+			    struct netlink_ext_ack *extack);
+	int (*get_plca_status)(struct phy_device *dev,
+			       struct phy_plca_status *plca_st);
 	int (*start_cable_test)(struct phy_device *phydev,
 				struct netlink_ext_ack *extack);
 	int (*start_cable_test_tdr)(struct phy_device *phydev,
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 89b43cda5bda..b82fdb0d82ed 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -774,6 +774,63 @@ struct phy_tdr_config {
 #define PHY_PAIR_ALL -1
 
 /**
+ * struct phy_plca_cfg - Configuration of the PLCA (Physical Layer Collision
+ * Avoidance) Reconciliation Sublayer.
+ *
+ * @version: read-only PLCA register map version. -1 = not available. Ignored
+ *   when setting the configuration. Format is the same as reported by the PLCA
+ *   IDVER register (31.CA00). -1 = not available.
+ * @enabled: PLCA configured mode (enabled/disabled). -1 = not available / don't
+ *   set. 0 = disabled, anything else = enabled.
+ * @node_id: the PLCA local node identifier. -1 = not available / don't set.
+ *   Allowed values [0 .. 254]. 255 = node disabled.
+ * @node_cnt: the PLCA node count (maximum number of nodes having a TO). Only
+ *   meaningful for the coordinator (node_id = 0). -1 = not available / don't
+ *   set. Allowed values [1 .. 255].
+ * @to_tmr: The value of the PLCA to_timer in bit-times, which determines the
+ *   PLCA transmit opportunity window opening. See IEEE802.3 Clause 148 for
+ *   more details. The to_timer shall be set equal over all nodes.
+ *   -1 = not available / don't set. Allowed values [0 .. 255].
+ * @burst_cnt: controls how many additional frames a node is allowed to send in
+ *   single transmit opportunity (TO). The default value of 0 means that the
+ *   node is allowed exactly one frame per TO. A value of 1 allows two frames
+ *   per TO, and so on. -1 = not available / don't set.
+ *   Allowed values [0 .. 255].
+ * @burst_tmr: controls how many bit times to wait for the MAC to send a new
+ *   frame before interrupting the burst. This value should be set to a value
+ *   greater than the MAC inter-packet gap (which is typically 96 bits).
+ *   -1 = not available / don't set. Allowed values [0 .. 255].
+ *
+ * A structure containing configuration parameters for setting/getting the PLCA
+ * RS configuration. The driver does not need to implement all the parameters,
+ * but should report what is actually used.
+ */
+struct phy_plca_cfg {
+	int version;
+	int enabled;
+	int node_id;
+	int node_cnt;
+	int to_tmr;
+	int burst_cnt;
+	int burst_tmr;
+};
+
+/**
+ * struct phy_plca_status - Status of the PLCA (Physical Layer Collision
+ * Avoidance) Reconciliation Sublayer.
+ *
+ * @pst: The PLCA status as reported by the PST bit in the PLCA STATUS
+ *	register(31.CA03), indicating BEACON activity.
+ *
+ * A structure containing status information of the PLCA RS configuration.
+ * The driver does not need to implement all the parameters, but should report
+ * what is actually used.
+ */
+struct phy_plca_status {
+	bool pst;
+};
+
+/**
  * struct phy_driver - Driver structure for a particular PHY type
  *
  * @mdiodrv: Data common to all MDIO devices
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 5799a9db034e..75b3d6d476ff 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -52,6 +52,9 @@ enum {
 	ETHTOOL_MSG_PSE_GET,
 	ETHTOOL_MSG_PSE_SET,
 	ETHTOOL_MSG_RSS_GET,
+	ETHTOOL_MSG_PLCA_GET_CFG,
+	ETHTOOL_MSG_PLCA_SET_CFG,
+	ETHTOOL_MSG_PLCA_GET_STATUS,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_USER_CNT,
@@ -99,6 +102,9 @@ enum {
 	ETHTOOL_MSG_MODULE_NTF,
 	ETHTOOL_MSG_PSE_GET_REPLY,
 	ETHTOOL_MSG_RSS_GET_REPLY,
+	ETHTOOL_MSG_PLCA_GET_CFG_REPLY,
+	ETHTOOL_MSG_PLCA_GET_STATUS_REPLY,
+	ETHTOOL_MSG_PLCA_NTF,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_KERNEL_CNT,
@@ -894,6 +900,25 @@ enum {
 	ETHTOOL_A_RSS_MAX = (__ETHTOOL_A_RSS_CNT - 1),
 };
 
+/* PLCA */
+
+enum {
+	ETHTOOL_A_PLCA_UNSPEC,
+	ETHTOOL_A_PLCA_HEADER,			/* nest - _A_HEADER_* */
+	ETHTOOL_A_PLCA_VERSION,			/* u16 */
+	ETHTOOL_A_PLCA_ENABLED,			/* u8  */
+	ETHTOOL_A_PLCA_STATUS,			/* u8  */
+	ETHTOOL_A_PLCA_NODE_CNT,		/* u32 */
+	ETHTOOL_A_PLCA_NODE_ID,			/* u32 */
+	ETHTOOL_A_PLCA_TO_TMR,			/* u32 */
+	ETHTOOL_A_PLCA_BURST_CNT,		/* u32 */
+	ETHTOOL_A_PLCA_BURST_TMR,		/* u32 */
+
+	/* add new constants above here */
+	__ETHTOOL_A_PLCA_CNT,
+	ETHTOOL_A_PLCA_MAX = (__ETHTOOL_A_PLCA_CNT - 1)
+};
+
 /* generic netlink info */
 #define ETHTOOL_GENL_NAME "ethtool"
 #define ETHTOOL_GENL_VERSION 1