This documents the possible MLO_PAUSE_* settings which can result from
different combinations of MAC_(A)SYM_PAUSE. Special note is paid to
settings which can result from user configuration (MLO_PAUSE_AN). The
autonegotiation results are more-or-less a direct consequence of IEEE
802.3 Table 28B-2.
Signed-off-by: Sean Anderson <[email protected]>
---
Changes in v6:
- Reword documentation, (hopefully) taking into account feedback
Changes in v3:
- New
include/linux/phylink.h | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 6d06896fc20d..1f997e14bf80 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -21,6 +21,35 @@ enum {
MLO_AN_FIXED, /* Fixed-link mode */
MLO_AN_INBAND, /* In-band protocol */
+ /* MAC_SYM_PAUSE and MAC_ASYM_PAUSE are used when configuring our
+ * autonegotiation advertisement. They correspond to the PAUSE and
+ * ASM_DIR bits defined by 802.3, respectively.
+ *
+ * The following table lists the values of tx_pause and rx_pause which
+ * might be requested in mac_link_up. The exact values depend on either
+ * the results of autonegotation (if MLO_PAUSE_AN is set) or user
+ * configuration (if MLO_PAUSE_AN is not set).
+ *
+ * MAC_SYM_PAUSE MAC_ASYM_PAUSE MLO_PAUSE_AN tx_pause/rx_pause
+ * ============= ============== ============ ==================
+ * 0 0 0 0/0
+ * 0 0 1 0/0
+ * 0 1 0 0/0, 0/1, 1/0, 1/1
+ * 0 1 1 0/0, 1/0
+ * 1 0 0 0/0, 1/1
+ * 1 0 1 0/0, 1/1
+ * 1 1 0 0/0, 0/1, 1/0, 1/1
+ * 1 1 1 0/0, 0/1, 1/1
+ *
+ * If you set MAC_ASYM_PAUSE, the user may request any combination of
+ * tx_pause and rx_pause. You do not have to support these
+ * combinations.
+ *
+ * However, you should support combinations of tx_pause and rx_pause
+ * which might be the result of autonegotation. For example, don't set
+ * MAC_SYM_PAUSE unless your device can support tx_pause and rx_pause
+ * at the same time.
+ */
MAC_SYM_PAUSE = BIT(0),
MAC_ASYM_PAUSE = BIT(1),
MAC_10HD = BIT(2),
--
2.35.1.1320.gc452695387.dirty