[PATCH net-next v5 6/8] net: phylink: Adjust advertisement based on rate adaptation
From: Sean Anderson
Date: Tue Sep 06 2022 - 12:41:57 EST
This adds support for adjusting the advertisement for pause-based rate
adaptation. This may result in a lossy link, since the final link settings
are not adjusted. Asymmetric pause support is necessary. It would be
possible for a MAC supporting only symmetric pause to use pause-based rate
adaptation, but only if pause reception was enabled as well.
Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx>
---
Changes in v5:
- Move phylink_cap_from_speed_duplex to this commit
Changes in v3:
- Add phylink_cap_from_speed_duplex to look up the mac capability
corresponding to the interface's speed.
- Include RATE_ADAPT_CRS; it's a few lines and it doesn't hurt.
Changes in v2:
- Determine the interface speed and max mac speed directly instead of
guessing based on the caps.
drivers/net/phy/phylink.c | 106 ++++++++++++++++++++++++++++++++++++--
include/linux/phylink.h | 3 +-
2 files changed, 105 insertions(+), 4 deletions(-)
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 8ce110c7be5c..4d73a58f4854 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -373,18 +373,70 @@ void phylink_caps_to_linkmodes(unsigned long *linkmodes, unsigned long caps)
}
EXPORT_SYMBOL_GPL(phylink_caps_to_linkmodes);
+static struct {
+ unsigned long mask;
+ int speed;
+ unsigned int duplex;
+} phylink_caps_params[] = {
+ { MAC_400000FD, SPEED_400000, DUPLEX_FULL },
+ { MAC_200000FD, SPEED_200000, DUPLEX_FULL },
+ { MAC_100000FD, SPEED_100000, DUPLEX_FULL },
+ { MAC_56000FD, SPEED_56000, DUPLEX_FULL },
+ { MAC_50000FD, SPEED_50000, DUPLEX_FULL },
+ { MAC_40000FD, SPEED_40000, DUPLEX_FULL },
+ { MAC_25000FD, SPEED_25000, DUPLEX_FULL },
+ { MAC_20000FD, SPEED_20000, DUPLEX_FULL },
+ { MAC_10000FD, SPEED_10000, DUPLEX_FULL },
+ { MAC_5000FD, SPEED_5000, DUPLEX_FULL },
+ { MAC_2500FD, SPEED_2500, DUPLEX_FULL },
+ { MAC_1000FD, SPEED_1000, DUPLEX_FULL },
+ { MAC_1000HD, SPEED_1000, DUPLEX_HALF },
+ { MAC_100FD, SPEED_100, DUPLEX_FULL },
+ { MAC_100HD, SPEED_100, DUPLEX_HALF },
+ { MAC_10FD, SPEED_10, DUPLEX_FULL },
+ { MAC_10HD, SPEED_10, DUPLEX_HALF },
+};
+
+/**
+ * phylink_cap_from_speed_duplex - Get mac capability from speed/duplex
+ * @speed: the speed to search for
+ * @duplex: the duplex to search for
+ *
+ * Find the mac capability for a given speed and duplex.
+ *
+ * Return: A mask with the mac capability patching @speed and @duplex, or 0 if
+ * there were no matches.
+ */
+static unsigned long phylink_cap_from_speed_duplex(int speed,
+ unsigned int duplex)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(phylink_caps_params); i++) {
+ if (speed == phylink_caps_params[i].speed &&
+ duplex == phylink_caps_params[i].duplex)
+ return phylink_caps_params[i].mask;
+ }
+
+ return 0;
+}
+
/**
* phylink_get_capabilities() - get capabilities for a given MAC
* @interface: phy interface mode defined by &typedef phy_interface_t
* @mac_capabilities: bitmask of MAC capabilities
+ * @rate_adaptation: type of rate adaptation being performed
*
* Get the MAC capabilities that are supported by the @interface mode and
* @mac_capabilities.
*/
unsigned long phylink_get_capabilities(phy_interface_t interface,
- unsigned long mac_capabilities)
+ unsigned long mac_capabilities,
+ int rate_adaptation)
{
+ int max_speed = phylink_interface_max_speed(interface);
unsigned long caps = MAC_SYM_PAUSE | MAC_ASYM_PAUSE;
+ unsigned long adapted_caps = 0;
switch (interface) {
case PHY_INTERFACE_MODE_USXGMII:
@@ -458,7 +510,53 @@ unsigned long phylink_get_capabilities(phy_interface_t interface,
break;
}
- return caps & mac_capabilities;
+ switch (rate_adaptation) {
+ case RATE_ADAPT_OPEN_LOOP:
+ /* TODO */
+ fallthrough;
+ case RATE_ADAPT_NONE:
+ adapted_caps = 0;
+ break;
+ case RATE_ADAPT_PAUSE: {
+ /* The MAC must support asymmetric pause towards the local
+ * device for this. We could allow just symmetric pause, but
+ * then we might have to renegotiate if the link partner
+ * doesn't support pause. This is because there's no way to
+ * accept pause frames without transmitting them if we only
+ * support symmetric pause.
+ */
+ if (!(mac_capabilities & MAC_SYM_PAUSE) ||
+ !(mac_capabilities & MAC_ASYM_PAUSE))
+ break;
+
+ /* We can't adapt if the MAC doesn't support the interface's
+ * max speed at full duplex.
+ */
+ if (mac_capabilities &
+ phylink_cap_from_speed_duplex(max_speed, DUPLEX_FULL)) {
+ /* Although a duplex-adapting phy might exist, we
+ * conservatively remove these modes because the MAC
+ * will not be aware of the half-duplex nature of the
+ * link.
+ */
+ adapted_caps = GENMASK(__fls(caps), __fls(MAC_10HD));
+ adapted_caps &= ~(MAC_1000HD | MAC_100HD | MAC_10HD);
+ }
+ break;
+ }
+ case RATE_ADAPT_CRS:
+ /* The MAC must support half duplex at the interface's max
+ * speed.
+ */
+ if (mac_capabilities &
+ phylink_cap_from_speed_duplex(max_speed, DUPLEX_HALF)) {
+ adapted_caps = GENMASK(__fls(caps), __fls(MAC_10HD));
+ adapted_caps &= mac_capabilities;
+ }
+ break;
+ }
+
+ return (caps & mac_capabilities) | adapted_caps;
}
EXPORT_SYMBOL_GPL(phylink_get_capabilities);
@@ -482,7 +580,8 @@ void phylink_generic_validate(struct phylink_config *config,
phylink_set_port_modes(mask);
phylink_set(mask, Autoneg);
caps = phylink_get_capabilities(state->interface,
- config->mac_capabilities);
+ config->mac_capabilities,
+ state->rate_adaptation);
phylink_caps_to_linkmodes(mask, caps);
linkmode_and(supported, supported, mask);
@@ -1514,6 +1613,7 @@ static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy,
config.interface = PHY_INTERFACE_MODE_NA;
else
config.interface = interface;
+ config.rate_adaptation = phy_get_rate_adaptation(phy, config.interface);
ret = phylink_validate(pl, supported, &config);
if (ret) {
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 1524846e01b4..c67a67620c8e 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -541,7 +541,8 @@ void pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
void phylink_caps_to_linkmodes(unsigned long *linkmodes, unsigned long caps);
unsigned long phylink_get_capabilities(phy_interface_t interface,
- unsigned long mac_capabilities);
+ unsigned long mac_capabilities,
+ int rate_adaptation);
void phylink_generic_validate(struct phylink_config *config,
unsigned long *supported,
struct phylink_link_state *state);
--
2.35.1.1320.gc452695387.dirty