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authorSean Anderson <sean.anderson@seco.com>2022-09-21 01:12:31 +0300
committerDavid S. Miller <davem@davemloft.net>2022-09-23 13:55:35 +0300
commit0c3e10cb44232833a50cb8e3e784c432906a60c1 (patch)
treed47c983e1b9c8ff206395c6753619c6fe0922649 /net
parent3e6eab8f3ef93cd78cd4b67f497ef6035eb073ad (diff)
downloadlinux-0c3e10cb44232833a50cb8e3e784c432906a60c1.tar.xz
net: phy: Add support for rate matching
This adds support for rate matching (also known as rate adaptation) to the phy subsystem. The general idea is that the phy interface runs at one speed, and the MAC throttles the rate at which it sends packets to the link speed. There's a good overview of several techniques for achieving this at [1]. This patch adds support for three: pause-frame based (such as in Aquantia phys), CRS-based (such as in 10PASS-TS and 2BASE-TL), and open-loop-based (such as in 10GBASE-W). This patch makes a few assumptions and a few non assumptions about the types of rate matching available. First, it assumes that different phys may use different forms of rate matching. Second, it assumes that phys can use rate matching for any of their supported link speeds (e.g. if a phy supports 10BASE-T and XGMII, then it can adapt XGMII to 10BASE-T). Third, it does not assume that all interface modes will use the same form of rate matching. Fourth, it does not assume that all phy devices will support rate matching (even if some do). Relaxing or strengthening these (non-)assumptions could result in a different API. For example, if all interface modes were assumed to use the same form of rate matching, then a bitmask of interface modes supportting rate matching would suffice. For some better visibility into the process, the current rate matching mode is exposed as part of the ethtool ksettings. For the moment, only read access is supported. I'm not sure what userspace might want to configure yet (disable it altogether, disable just one mode, specify the mode to use, etc.). For the moment, since only pause-based rate adaptation support is added in the next few commits, rate matching can be disabled altogether by adjusting the advertisement. 802.3 calls this feature "rate adaptation" in clause 49 (10GBASE-R) and "rate matching" in clause 61 (10PASS-TL and 2BASE-TS). Aquantia also calls this feature "rate adaptation". I chose "rate matching" because it is shorter, and because Russell doesn't think "adaptation" is correct in this context. Signed-off-by: Sean Anderson <sean.anderson@seco.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ethtool/ioctl.c1
-rw-r--r--net/ethtool/linkmodes.c5
2 files changed, 6 insertions, 0 deletions
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 9298eb3251cb..57e7238a4136 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -571,6 +571,7 @@ static int ethtool_get_link_ksettings(struct net_device *dev,
= __ETHTOOL_LINK_MODE_MASK_NU32;
link_ksettings.base.master_slave_cfg = MASTER_SLAVE_CFG_UNSUPPORTED;
link_ksettings.base.master_slave_state = MASTER_SLAVE_STATE_UNSUPPORTED;
+ link_ksettings.base.rate_matching = RATE_MATCH_NONE;
return store_link_ksettings_for_user(useraddr, &link_ksettings);
}
diff --git a/net/ethtool/linkmodes.c b/net/ethtool/linkmodes.c
index 99b29b4fe947..126e06c713a3 100644
--- a/net/ethtool/linkmodes.c
+++ b/net/ethtool/linkmodes.c
@@ -70,6 +70,7 @@ static int linkmodes_reply_size(const struct ethnl_req_info *req_base,
+ nla_total_size(sizeof(u32)) /* LINKMODES_SPEED */
+ nla_total_size(sizeof(u32)) /* LINKMODES_LANES */
+ nla_total_size(sizeof(u8)) /* LINKMODES_DUPLEX */
+ + nla_total_size(sizeof(u8)) /* LINKMODES_RATE_MATCHING */
+ 0;
ret = ethnl_bitset_size(ksettings->link_modes.advertising,
ksettings->link_modes.supported,
@@ -143,6 +144,10 @@ static int linkmodes_fill_reply(struct sk_buff *skb,
lsettings->master_slave_state))
return -EMSGSIZE;
+ if (nla_put_u8(skb, ETHTOOL_A_LINKMODES_RATE_MATCHING,
+ lsettings->rate_matching))
+ return -EMSGSIZE;
+
return 0;
}