| // 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); |
