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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);
/**
* 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);
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