Olivier Deprez | 157378f | 2022-04-04 15:47:50 +0200 | [diff] [blame^] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | #include <linux/linkmode.h> |
| 3 | |
| 4 | /** |
| 5 | * linkmode_resolve_pause - resolve the allowable pause modes |
| 6 | * @local_adv: local advertisement in ethtool format |
| 7 | * @partner_adv: partner advertisement in ethtool format |
| 8 | * @tx_pause: pointer to bool to indicate whether transmit pause should be |
| 9 | * enabled. |
| 10 | * @rx_pause: pointer to bool to indicate whether receive pause should be |
| 11 | * enabled. |
| 12 | * |
| 13 | * Flow control is resolved according to our and the link partners |
| 14 | * advertisements using the following drawn from the 802.3 specs: |
| 15 | * Local device Link partner |
| 16 | * Pause AsymDir Pause AsymDir Result |
| 17 | * 0 X 0 X Disabled |
| 18 | * 0 1 1 0 Disabled |
| 19 | * 0 1 1 1 TX |
| 20 | * 1 0 0 X Disabled |
| 21 | * 1 X 1 X TX+RX |
| 22 | * 1 1 0 1 RX |
| 23 | */ |
| 24 | void linkmode_resolve_pause(const unsigned long *local_adv, |
| 25 | const unsigned long *partner_adv, |
| 26 | bool *tx_pause, bool *rx_pause) |
| 27 | { |
| 28 | __ETHTOOL_DECLARE_LINK_MODE_MASK(m); |
| 29 | |
| 30 | linkmode_and(m, local_adv, partner_adv); |
| 31 | if (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT, m)) { |
| 32 | *tx_pause = true; |
| 33 | *rx_pause = true; |
| 34 | } else if (linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, m)) { |
| 35 | *tx_pause = linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT, |
| 36 | partner_adv); |
| 37 | *rx_pause = linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT, |
| 38 | local_adv); |
| 39 | } else { |
| 40 | *tx_pause = false; |
| 41 | *rx_pause = false; |
| 42 | } |
| 43 | } |
| 44 | EXPORT_SYMBOL_GPL(linkmode_resolve_pause); |
| 45 | |
| 46 | /** |
| 47 | * linkmode_set_pause - set the pause mode advertisement |
| 48 | * @advertisement: advertisement in ethtool format |
| 49 | * @tx: boolean from ethtool struct ethtool_pauseparam tx_pause member |
| 50 | * @rx: boolean from ethtool struct ethtool_pauseparam rx_pause member |
| 51 | * |
| 52 | * Configure the advertised Pause and Asym_Pause bits according to the |
| 53 | * capabilities of provided in @tx and @rx. |
| 54 | * |
| 55 | * We convert as follows: |
| 56 | * tx rx Pause AsymDir |
| 57 | * 0 0 0 0 |
| 58 | * 0 1 1 1 |
| 59 | * 1 0 0 1 |
| 60 | * 1 1 1 0 |
| 61 | * |
| 62 | * Note: this translation from ethtool tx/rx notation to the advertisement |
| 63 | * is actually very problematical. Here are some examples: |
| 64 | * |
| 65 | * For tx=0 rx=1, meaning transmit is unsupported, receive is supported: |
| 66 | * |
| 67 | * Local device Link partner |
| 68 | * Pause AsymDir Pause AsymDir Result |
| 69 | * 1 1 1 0 TX + RX - but we have no TX support. |
| 70 | * 1 1 0 1 Only this gives RX only |
| 71 | * |
| 72 | * For tx=1 rx=1, meaning we have the capability to transmit and receive |
| 73 | * pause frames: |
| 74 | * |
| 75 | * Local device Link partner |
| 76 | * Pause AsymDir Pause AsymDir Result |
| 77 | * 1 0 0 1 Disabled - but since we do support tx and rx, |
| 78 | * this should resolve to RX only. |
| 79 | * |
| 80 | * Hence, asking for: |
| 81 | * rx=1 tx=0 gives Pause+AsymDir advertisement, but we may end up |
| 82 | * resolving to tx+rx pause or only rx pause depending on |
| 83 | * the partners advertisement. |
| 84 | * rx=0 tx=1 gives AsymDir only, which will only give tx pause if |
| 85 | * the partners advertisement allows it. |
| 86 | * rx=1 tx=1 gives Pause only, which will only allow tx+rx pause |
| 87 | * if the other end also advertises Pause. |
| 88 | */ |
| 89 | void linkmode_set_pause(unsigned long *advertisement, bool tx, bool rx) |
| 90 | { |
| 91 | linkmode_mod_bit(ETHTOOL_LINK_MODE_Pause_BIT, advertisement, rx); |
| 92 | linkmode_mod_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, advertisement, |
| 93 | rx ^ tx); |
| 94 | } |
| 95 | EXPORT_SYMBOL_GPL(linkmode_set_pause); |