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(dst: m, a: local_adv, b: partner_adv); |
31 | if (linkmode_test_bit(nr: ETHTOOL_LINK_MODE_Pause_BIT, addr: m)) { |
32 | *tx_pause = true; |
33 | *rx_pause = true; |
34 | } else if (linkmode_test_bit(nr: ETHTOOL_LINK_MODE_Asym_Pause_BIT, addr: m)) { |
35 | *tx_pause = linkmode_test_bit(nr: ETHTOOL_LINK_MODE_Pause_BIT, |
36 | addr: partner_adv); |
37 | *rx_pause = linkmode_test_bit(nr: ETHTOOL_LINK_MODE_Pause_BIT, |
38 | addr: 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(nr: ETHTOOL_LINK_MODE_Pause_BIT, addr: advertisement, set: rx); |
92 | linkmode_mod_bit(nr: ETHTOOL_LINK_MODE_Asym_Pause_BIT, addr: advertisement, |
93 | set: rx ^ tx); |
94 | } |
95 | EXPORT_SYMBOL_GPL(linkmode_set_pause); |
96 | |