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Message-Id: <E1tIUsJ-006IUn-H3@rmk-PC.armlinux.org.uk>
Date: Tue, 03 Dec 2024 15:31:43 +0000
From: "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>
To: Andrew Lunn <andrew@...n.ch>,
Heiner Kallweit <hkallweit1@...il.com>
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
netdev@...r.kernel.org
Subject: [PATCH net-next 12/13] net: phylink: add negotiation of in-band
capabilities
Support for in-band signalling with Serdes links is uncertain. Some
PHYs do not support in-band for e.g. SGMII. Some PCS do not support
in-band for 2500Base-X. Some PCS require in-band for Base-X protocols.
Simply using what is in DT is insufficient when we have hot-pluggable
PHYs e.g. in the form of SFP modules, which may not provide the
in-band signalling.
In order to address this, we have introduced phy_inband_caps() and
pcs_inband_caps() functions to allow phylink to retrieve the
capabilities from each end of the PCS/PHY link. This commit adds code
to resolve whether in-band will be used in the various scenarios that
we have: In-band not being used, PHY present using SGMII or Base-X,
PHY not present. We also deal with no capabilties provided.
Signed-off-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
---
drivers/net/phy/phylink.c | 154 +++++++++++++++++++++++++++++++++++---
1 file changed, 144 insertions(+), 10 deletions(-)
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 42f3c7ccbf38..b0881fa9c72e 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -75,6 +75,7 @@ struct phylink {
struct mutex state_mutex;
struct phylink_link_state phy_state;
+ unsigned int phy_ib_mode;
struct work_struct resolve;
unsigned int pcs_neg_mode;
unsigned int pcs_state;
@@ -1153,10 +1154,18 @@ static void phylink_pcs_neg_mode(struct phylink *pl, struct phylink_pcs *pcs,
phy_interface_t interface,
const unsigned long *advertising)
{
+ unsigned int pcs_ib_caps = 0;
+ unsigned int phy_ib_caps = 0;
unsigned int neg_mode, mode;
+ enum {
+ INBAND_CISCO_SGMII,
+ INBAND_BASEX,
+ } type;
mode = pl->req_link_an_mode;
+ pl->phy_ib_mode = 0;
+
switch (interface) {
case PHY_INTERFACE_MODE_SGMII:
case PHY_INTERFACE_MODE_QSGMII:
@@ -1168,10 +1177,7 @@ static void phylink_pcs_neg_mode(struct phylink *pl, struct phylink_pcs *pcs,
* inband communication. Note: there exist PHYs that run
* with SGMII but do not send the inband data.
*/
- if (!phylink_autoneg_inband(mode))
- neg_mode = PHYLINK_PCS_NEG_OUTBAND;
- else
- neg_mode = PHYLINK_PCS_NEG_INBAND_ENABLED;
+ type = INBAND_CISCO_SGMII;
break;
case PHY_INTERFACE_MODE_1000BASEX:
@@ -1182,18 +1188,139 @@ static void phylink_pcs_neg_mode(struct phylink *pl, struct phylink_pcs *pcs,
* as well, but drivers may not support this, so may
* need to override this.
*/
- if (!phylink_autoneg_inband(mode))
+ type = INBAND_BASEX;
+ break;
+
+ default:
+ pl->pcs_neg_mode = PHYLINK_PCS_NEG_NONE;
+ pl->act_link_an_mode = mode;
+ return;
+ }
+
+ if (pcs)
+ pcs_ib_caps = phylink_pcs_inband_caps(pcs, interface);
+
+ if (pl->phydev)
+ phy_ib_caps = phy_inband_caps(pl->phydev, interface);
+
+ phylink_dbg(pl, "interface %s inband modes: pcs=%02x phy=%02x\n",
+ phy_modes(interface), pcs_ib_caps, phy_ib_caps);
+
+ if (!phylink_autoneg_inband(mode)) {
+ bool pcs_ib_only = false;
+ bool phy_ib_only = false;
+
+ if (pcs_ib_caps && pcs_ib_caps != LINK_INBAND_DISABLE) {
+ /* PCS supports reporting in-band capabilities, and
+ * supports more than disable mode.
+ */
+ if (pcs_ib_caps & LINK_INBAND_DISABLE)
+ neg_mode = PHYLINK_PCS_NEG_OUTBAND;
+ else if (pcs_ib_caps & LINK_INBAND_ENABLE)
+ pcs_ib_only = true;
+ }
+
+ if (phy_ib_caps && phy_ib_caps != LINK_INBAND_DISABLE) {
+ /* PHY supports in-band capabilities, and supports
+ * more than disable mode.
+ */
+ if (phy_ib_caps & LINK_INBAND_DISABLE)
+ pl->phy_ib_mode = LINK_INBAND_DISABLE;
+ else if (phy_ib_caps & LINK_INBAND_BYPASS)
+ pl->phy_ib_mode = LINK_INBAND_BYPASS;
+ else if (phy_ib_caps & LINK_INBAND_ENABLE)
+ phy_ib_only = true;
+ }
+
+ /* If either the PCS or PHY requires inband to be enabled,
+ * this is an invalid configuration. Provide a diagnostic
+ * message for this case, but don't try to force the issue.
+ */
+ if (pcs_ib_only || phy_ib_only)
+ phylink_warn(pl,
+ "firmware wants %s mode, but %s%s%s requires inband\n",
+ phylink_an_mode_str(mode),
+ pcs_ib_only ? "PCS" : "",
+ pcs_ib_only && phy_ib_only ? " and " : "",
+ phy_ib_only ? "PHY" : "");
+
+ neg_mode = PHYLINK_PCS_NEG_OUTBAND;
+ } else if (type == INBAND_CISCO_SGMII || pl->phydev) {
+ /* For SGMII modes which are designed to be used with PHYs, or
+ * Base-X with a PHY, we try to use in-band mode where-ever
+ * possible. However, there are some PHYs e.g. BCM84881 which
+ * do not support in-band.
+ */
+ const unsigned int inband_ok = LINK_INBAND_ENABLE |
+ LINK_INBAND_BYPASS;
+ const unsigned int outband_ok = LINK_INBAND_DISABLE |
+ LINK_INBAND_BYPASS;
+ /* PCS PHY
+ * D E D E
+ * 0 0 0 0 no information inband enabled
+ * 1 0 0 0 pcs doesn't support outband
+ * 0 1 0 0 pcs required inband enabled
+ * 1 1 0 0 pcs optional inband enabled
+ * 0 0 1 0 phy doesn't support outband
+ * 1 0 1 0 pcs+phy doesn't support outband
+ * 0 1 1 0 pcs required, phy doesn't support, invalid
+ * 1 1 1 0 pcs optional, phy doesn't support, outband
+ * 0 0 0 1 phy required inband enabled
+ * 1 0 0 1 pcs doesn't support, phy required, invalid
+ * 0 1 0 1 pcs+phy required inband enabled
+ * 1 1 0 1 pcs optional, phy required inband enabled
+ * 0 0 1 1 phy optional inband enabled
+ * 1 0 1 1 pcs doesn't support, phy optional, outband
+ * 0 1 1 1 pcs required, phy optional inband enabled
+ * 1 1 1 1 pcs+phy optional inband enabled
+ */
+ if ((!pcs_ib_caps || pcs_ib_caps & inband_ok) &&
+ (!phy_ib_caps || phy_ib_caps & inband_ok)) {
+ /* In-band supported or unknown at both ends. Enable
+ * in-band mode with or without bypass at the PHY.
+ */
+ if (phy_ib_caps & LINK_INBAND_ENABLE)
+ pl->phy_ib_mode = LINK_INBAND_ENABLE;
+ else if (phy_ib_caps & LINK_INBAND_BYPASS)
+ pl->phy_ib_mode = LINK_INBAND_BYPASS;
+
+ neg_mode = PHYLINK_PCS_NEG_INBAND_ENABLED;
+ } else if ((!pcs_ib_caps || pcs_ib_caps & outband_ok) &&
+ (!phy_ib_caps || phy_ib_caps & outband_ok)) {
+ /* Either in-band not supported at at least one end.
+ * In-band bypass at the other end is possible.
+ */
+ if (phy_ib_caps & LINK_INBAND_DISABLE)
+ pl->phy_ib_mode = LINK_INBAND_DISABLE;
+ else if (phy_ib_caps & LINK_INBAND_BYPASS)
+ pl->phy_ib_mode = LINK_INBAND_BYPASS;
+
neg_mode = PHYLINK_PCS_NEG_OUTBAND;
+ if (pl->phydev)
+ mode = MLO_AN_PHY;
+ } else {
+ /* invalid */
+ phylink_warn(pl, "%s: incompatible in-band capabilities, trying in-band",
+ phy_modes(interface));
+ neg_mode = PHYLINK_PCS_NEG_INBAND_ENABLED;
+ }
+ } else {
+ /* For Base-X without a PHY */
+ if (pcs_ib_caps == LINK_INBAND_DISABLE)
+ /* If the PCS doesn't support inband, then inband must
+ * be disabled.
+ */
+ neg_mode = PHYLINK_PCS_NEG_INBAND_DISABLED;
+ else if (pcs_ib_caps == LINK_INBAND_ENABLE)
+ /* If the PCS requires inband, then inband must always
+ * be enabled.
+ */
+ neg_mode = PHYLINK_PCS_NEG_INBAND_ENABLED;
else if (linkmode_test_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,
advertising))
neg_mode = PHYLINK_PCS_NEG_INBAND_ENABLED;
else
neg_mode = PHYLINK_PCS_NEG_INBAND_DISABLED;
- break;
-
- default:
- neg_mode = PHYLINK_PCS_NEG_NONE;
- break;
}
pl->pcs_neg_mode = neg_mode;
@@ -1292,6 +1419,13 @@ static void phylink_major_config(struct phylink *pl, bool restart,
ERR_PTR(err));
}
+ if (pl->phydev && pl->phy_ib_mode) {
+ err = phy_config_inband(pl->phydev, pl->phy_ib_mode);
+ if (err < 0)
+ phylink_err(pl, "phy_config_inband: %pe\n",
+ ERR_PTR(err));
+ }
+
if (pl->sfp_bus) {
rate_kbd = phylink_interface_signal_rate(state->interface);
if (rate_kbd)
--
2.30.2
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