| 1 | |
| 2 | #include <linux/linkmode.h>
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| 3 |
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| 4 | |
| 5 | * linkmode_resolve_pause - resolve the allowable pause modes
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| 6 | * @local_adv: local advertisement in ethtool format
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| 7 | * @partner_adv: partner advertisement in ethtool format
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| 8 | * @tx_pause: pointer to bool to indicate whether transmit pause should be
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| 9 | * enabled.
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| 10 | * @rx_pause: pointer to bool to indicate whether receive pause should be
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| 11 | * enabled.
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| 12 | *
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| 13 | * Flow control is resolved according to our and the link partners
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| 14 | * advertisements using the following drawn from the 802.3 specs:
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| 15 | * Local device Link partner
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| 16 | * Pause AsymDir Pause AsymDir Result
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| 17 | * 0 X 0 X Disabled
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| 18 | * 0 1 1 0 Disabled
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| 19 | * 0 1 1 1 TX
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| 20 | * 1 0 0 X Disabled
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| 21 | * 1 X 1 X TX+RX
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| 22 | * 1 1 0 1 RX
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| 23 |
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| 24 | void linkmode_resolve_pause(const unsigned long *local_adv,
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| 25 | const unsigned long *partner_adv,
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| 26 | bool *tx_pause, bool *rx_pause)
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| 27 | {
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| 28 | __ETHTOOL_DECLARE_LINK_MODE_MASK(m);
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| 29 |
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| 30 | linkmode_and(m, local_adv, partner_adv);
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| 31 | if (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT, m)) {
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| 32 | *tx_pause = true;
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| 33 | *rx_pause = true;
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| 34 | } else if (linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, m)) {
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| 35 | *tx_pause = linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
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| 36 | partner_adv);
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| 37 | *rx_pause = linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
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| 38 | local_adv);
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| 39 | } else {
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| 40 | *tx_pause = false;
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| 41 | *rx_pause = false;
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| 42 | }
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| 43 | }
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| 44 | EXPORT_SYMBOL_GPL(linkmode_resolve_pause);
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| 45 |
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| 46 | |
| 47 | * linkmode_set_pause - set the pause mode advertisement
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| 48 | * @advertisement: advertisement in ethtool format
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| 49 | * @tx: boolean from ethtool struct ethtool_pauseparam tx_pause member
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| 50 | * @rx: boolean from ethtool struct ethtool_pauseparam rx_pause member
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| 51 | *
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| 52 | * Configure the advertised Pause and Asym_Pause bits according to the
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| 53 | * capabilities of provided in @tx and @rx.
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| 54 | *
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| 55 | * We convert as follows:
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| 56 | * tx rx Pause AsymDir
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| 57 | * 0 0 0 0
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| 58 | * 0 1 1 1
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| 59 | * 1 0 0 1
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| 60 | * 1 1 1 0
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| 61 | *
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| 62 | * Note: this translation from ethtool tx/rx notation to the advertisement
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| 63 | * is actually very problematical. Here are some examples:
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| 64 | *
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| 65 | * For tx=0 rx=1, meaning transmit is unsupported, receive is supported:
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| 66 | *
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| 67 | * Local device Link partner
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| 68 | * Pause AsymDir Pause AsymDir Result
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| 69 | * 1 1 1 0 TX + RX - but we have no TX support.
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| 70 | * 1 1 0 1 Only this gives RX only
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| 71 | *
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| 72 | * For tx=1 rx=1, meaning we have the capability to transmit and receive
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| 73 | * pause frames:
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| 74 | *
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| 75 | * Local device Link partner
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| 76 | * Pause AsymDir Pause AsymDir Result
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| 77 | * 1 0 0 1 Disabled - but since we do support tx and rx,
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| 78 | * this should resolve to RX only.
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| 79 | *
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| 80 | * Hence, asking for:
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| 81 | * rx=1 tx=0 gives Pause+AsymDir advertisement, but we may end up
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| 82 | * resolving to tx+rx pause or only rx pause depending on
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| 83 | * the partners advertisement.
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| 84 | * rx=0 tx=1 gives AsymDir only, which will only give tx pause if
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| 85 | * the partners advertisement allows it.
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| 86 | * rx=1 tx=1 gives Pause only, which will only allow tx+rx pause
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| 87 | * if the other end also advertises Pause.
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| 88 |
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| 89 | void linkmode_set_pause(unsigned long *advertisement, bool tx, bool rx)
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| 90 | {
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| 91 | linkmode_mod_bit(ETHTOOL_LINK_MODE_Pause_BIT, advertisement, rx);
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| 92 | linkmode_mod_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, advertisement,
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| 93 | rx ^ tx);
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| 94 | }
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| 95 | EXPORT_SYMBOL_GPL(linkmode_set_pause);
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