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-rw-r--r--drivers/net/phy/linkmode.c95
1 files changed, 95 insertions, 0 deletions
diff --git a/drivers/net/phy/linkmode.c b/drivers/net/phy/linkmode.c
new file mode 100644
index 000000000..f60560fe3
--- /dev/null
+++ b/drivers/net/phy/linkmode.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/linkmode.h>
+
+/**
+ * linkmode_resolve_pause - resolve the allowable pause modes
+ * @local_adv: local advertisement in ethtool format
+ * @partner_adv: partner advertisement in ethtool format
+ * @tx_pause: pointer to bool to indicate whether transmit pause should be
+ * enabled.
+ * @rx_pause: pointer to bool to indicate whether receive pause should be
+ * enabled.
+ *
+ * Flow control is resolved according to our and the link partners
+ * advertisements using the following drawn from the 802.3 specs:
+ * Local device Link partner
+ * Pause AsymDir Pause AsymDir Result
+ * 0 X 0 X Disabled
+ * 0 1 1 0 Disabled
+ * 0 1 1 1 TX
+ * 1 0 0 X Disabled
+ * 1 X 1 X TX+RX
+ * 1 1 0 1 RX
+ */
+void linkmode_resolve_pause(const unsigned long *local_adv,
+ const unsigned long *partner_adv,
+ bool *tx_pause, bool *rx_pause)
+{
+ __ETHTOOL_DECLARE_LINK_MODE_MASK(m);
+
+ linkmode_and(m, local_adv, partner_adv);
+ if (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT, m)) {
+ *tx_pause = true;
+ *rx_pause = true;
+ } else if (linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, m)) {
+ *tx_pause = linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
+ partner_adv);
+ *rx_pause = linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
+ local_adv);
+ } else {
+ *tx_pause = false;
+ *rx_pause = false;
+ }
+}
+EXPORT_SYMBOL_GPL(linkmode_resolve_pause);
+
+/**
+ * linkmode_set_pause - set the pause mode advertisement
+ * @advertisement: advertisement in ethtool format
+ * @tx: boolean from ethtool struct ethtool_pauseparam tx_pause member
+ * @rx: boolean from ethtool struct ethtool_pauseparam rx_pause member
+ *
+ * Configure the advertised Pause and Asym_Pause bits according to the
+ * capabilities of provided in @tx and @rx.
+ *
+ * We convert as follows:
+ * tx rx Pause AsymDir
+ * 0 0 0 0
+ * 0 1 1 1
+ * 1 0 0 1
+ * 1 1 1 0
+ *
+ * Note: this translation from ethtool tx/rx notation to the advertisement
+ * is actually very problematical. Here are some examples:
+ *
+ * For tx=0 rx=1, meaning transmit is unsupported, receive is supported:
+ *
+ * Local device Link partner
+ * Pause AsymDir Pause AsymDir Result
+ * 1 1 1 0 TX + RX - but we have no TX support.
+ * 1 1 0 1 Only this gives RX only
+ *
+ * For tx=1 rx=1, meaning we have the capability to transmit and receive
+ * pause frames:
+ *
+ * Local device Link partner
+ * Pause AsymDir Pause AsymDir Result
+ * 1 0 0 1 Disabled - but since we do support tx and rx,
+ * this should resolve to RX only.
+ *
+ * Hence, asking for:
+ * rx=1 tx=0 gives Pause+AsymDir advertisement, but we may end up
+ * resolving to tx+rx pause or only rx pause depending on
+ * the partners advertisement.
+ * rx=0 tx=1 gives AsymDir only, which will only give tx pause if
+ * the partners advertisement allows it.
+ * rx=1 tx=1 gives Pause only, which will only allow tx+rx pause
+ * if the other end also advertises Pause.
+ */
+void linkmode_set_pause(unsigned long *advertisement, bool tx, bool rx)
+{
+ linkmode_mod_bit(ETHTOOL_LINK_MODE_Pause_BIT, advertisement, rx);
+ linkmode_mod_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, advertisement,
+ rx ^ tx);
+}
+EXPORT_SYMBOL_GPL(linkmode_set_pause);