diff mbox series

[RFC,net-next,09/16] net: phylink: add pcs_inband_caps() method

Message ID E1tFrob-005xQS-Hz@rmk-PC.armlinux.org.uk (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series net: add negotiation of in-band capabilities | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/build_tools success Errors and warnings before: 0 (+0) this patch: 0 (+0)
netdev/cc_maintainers success CCed 11 of 11 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 79 this patch: 79
netdev/checkpatch fail CHECK: Alignment should match open parenthesis ERROR: code indent should use tabs where possible
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc fail Errors and warnings before: 27 this patch: 28
netdev/source_inline success Was 0 now: 0

Commit Message

Russell King (Oracle) Nov. 26, 2024, 9:25 a.m. UTC
Add a pcs_inband_caps() method to query the PCS for its inband link
capabilities, and use this to determine whether link modes used with
optical SFPs can be supported.

When a PCS does not provide a method, we allow inband negotiation to
be either on or off, making this a no-op until the pcs_inband_caps()
method is implemented by a PCS driver.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/phylink.c | 60 +++++++++++++++++++++++++++++++++++++++
 include/linux/phylink.h   | 17 +++++++++++
 2 files changed, 77 insertions(+)
diff mbox series

Patch

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index e43a083cec57..ca52cb23187d 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -990,6 +990,15 @@  static void phylink_resolve_an_pause(struct phylink_link_state *state)
 	}
 }
 
+static unsigned int phylink_pcs_inband_caps(struct phylink_pcs *pcs,
+				    phy_interface_t interface)
+{
+	if (pcs && pcs->ops->pcs_inband_caps)
+		return pcs->ops->pcs_inband_caps(pcs, interface);
+
+	return 0;
+}
+
 static void phylink_pcs_pre_config(struct phylink_pcs *pcs,
 				   phy_interface_t interface)
 {
@@ -1043,6 +1052,24 @@  static void phylink_pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
 		pcs->ops->pcs_link_up(pcs, neg_mode, interface, speed, duplex);
 }
 
+/* Query inband for a specific interface mode, asking the MAC for the
+ * PCS which will be used to handle the interface mode.
+ */
+static unsigned int phylink_inband_caps(struct phylink *pl,
+					 phy_interface_t interface)
+{
+	struct phylink_pcs *pcs;
+
+	if (!pl->mac_ops->mac_select_pcs)
+		return 0;
+
+	pcs = pl->mac_ops->mac_select_pcs(pl->config, interface);
+	if (!pcs)
+		return 0;
+
+	return phylink_pcs_inband_caps(pcs, interface);
+}
+
 static void phylink_pcs_poll_stop(struct phylink *pl)
 {
 	if (pl->cfg_link_an_mode == MLO_AN_INBAND)
@@ -2541,6 +2568,26 @@  int phylink_ethtool_ksettings_get(struct phylink *pl,
 }
 EXPORT_SYMBOL_GPL(phylink_ethtool_ksettings_get);
 
+static bool phylink_validate_pcs_inband_autoneg(struct phylink *pl,
+					        phy_interface_t interface,
+						unsigned long *adv)
+{
+	unsigned int inband = phylink_inband_caps(pl, interface);
+	unsigned int mask;
+
+	/* If the PCS doesn't implement inband support, be permissive. */
+	if (!inband)
+		return true;
+
+	if (linkmode_test_bit(ETHTOOL_LINK_MODE_Autoneg_BIT, adv))
+		mask = LINK_INBAND_ENABLE;
+	else
+		mask = LINK_INBAND_DISABLE;
+
+	/* Check whether the PCS implements the required mode */
+	return !!(inband & mask);
+}
+
 /**
  * phylink_ethtool_ksettings_set() - set the link settings
  * @pl: a pointer to a &struct phylink returned from phylink_create()
@@ -2671,6 +2718,13 @@  int phylink_ethtool_ksettings_set(struct phylink *pl,
 	    phylink_is_empty_linkmode(config.advertising))
 		return -EINVAL;
 
+	/* Validate the autonegotiation state. We don't have a PHY in this
+	 * situation, so the PCS is the media-facing entity.
+	 */
+	if (!phylink_validate_pcs_inband_autoneg(pl, config.interface,
+						 config.advertising))
+		return -EINVAL;
+
 	mutex_lock(&pl->state_mutex);
 	pl->link_config.speed = config.speed;
 	pl->link_config.duplex = config.duplex;
@@ -3350,6 +3404,12 @@  static int phylink_sfp_config_optical(struct phylink *pl)
 	phylink_dbg(pl, "optical SFP: chosen %s interface\n",
 		    phy_modes(interface));
 
+	if (!phylink_validate_pcs_inband_autoneg(pl, interface,
+						 config.advertising)) {
+		phylink_err(pl, "autoneg setting not compatible with PCS");
+		return -EINVAL;
+	}
+
 	config.interface = interface;
 
 	/* Ignore errors if we're expecting a PHY to attach later */
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 595139797acb..ef26111d0040 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -422,6 +422,7 @@  struct phylink_pcs {
 /**
  * struct phylink_pcs_ops - MAC PCS operations structure.
  * @pcs_validate: validate the link configuration.
+ * @pcs_inband_caps: query inband support for interface mode.
  * @pcs_enable: enable the PCS.
  * @pcs_disable: disable the PCS.
  * @pcs_pre_config: pre-mac_config method (for errata)
@@ -437,6 +438,8 @@  struct phylink_pcs {
 struct phylink_pcs_ops {
 	int (*pcs_validate)(struct phylink_pcs *pcs, unsigned long *supported,
 			    const struct phylink_link_state *state);
+	unsigned int (*pcs_inband_caps)(struct phylink_pcs *pcs,
+					phy_interface_t interface);
 	int (*pcs_enable)(struct phylink_pcs *pcs);
 	void (*pcs_disable)(struct phylink_pcs *pcs);
 	void (*pcs_pre_config)(struct phylink_pcs *pcs,
@@ -473,6 +476,20 @@  struct phylink_pcs_ops {
 int pcs_validate(struct phylink_pcs *pcs, unsigned long *supported,
 		 const struct phylink_link_state *state);
 
+/**
+ * pcs_inband_caps - query PCS in-band capabilities for interface mode.
+ * @pcs: a pointer to a &struct phylink_pcs.
+ * @interface: interface mode to be queried
+ *
+ * Returns zero if it is unknown what in-band signalling is supported by the
+ * PHY (e.g. because the PHY driver doesn't implement the method.) Otherwise,
+ * returns a bit mask of the LINK_INBAND_* values from
+ * &enum link_inband_signalling to describe which inband modes are supported
+ * for this interface mode.
+ */
+unsigned int pcs_inband_caps(struct phylink_pcs *pcs,
+			     phy_interface_t interface);
+
 /**
  * pcs_enable() - enable the PCS.
  * @pcs: a pointer to a &struct phylink_pcs.