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drivers/net/phy/linkmode.c 3.34 KB
a87ae8a96   Russell King   net: add helpers ...
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  // 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);
45c767fae   Russell King   net: add linkmode...
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  /**
   * 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);