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net: phylink: add negotiation of in-band capabilities

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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@armlinux.org.uk>
Link: https://patch.msgid.link/E1tIUsJ-006IUn-H3@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Russell King (Oracle) 2024-12-03 15:31:43 +00:00 committed by Jakub Kicinski
parent d4169f0c76
commit 5fd0f1a02e
1 changed files with 144 additions and 10 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

154
drivers/net/phy/phylink.c
View file

@ -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)