295 lines
12 KiB
Diff
295 lines
12 KiB
Diff
From 0c3e10cb44232833a50cb8e3e784c432906a60c1 Mon Sep 17 00:00:00 2001
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From: Sean Anderson <sean.anderson@seco.com>
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Date: Tue, 20 Sep 2022 18:12:31 -0400
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Subject: [PATCH] net: phy: Add support for rate matching
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This adds support for rate matching (also known as rate adaptation) to
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the phy subsystem. The general idea is that the phy interface runs at
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one speed, and the MAC throttles the rate at which it sends packets to
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the link speed. There's a good overview of several techniques for
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achieving this at [1]. This patch adds support for three: pause-frame
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based (such as in Aquantia phys), CRS-based (such as in 10PASS-TS and
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2BASE-TL), and open-loop-based (such as in 10GBASE-W).
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This patch makes a few assumptions and a few non assumptions about the
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types of rate matching available. First, it assumes that different phys
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may use different forms of rate matching. Second, it assumes that phys
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can use rate matching for any of their supported link speeds (e.g. if a
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phy supports 10BASE-T and XGMII, then it can adapt XGMII to 10BASE-T).
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Third, it does not assume that all interface modes will use the same
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form of rate matching. Fourth, it does not assume that all phy devices
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will support rate matching (even if some do). Relaxing or strengthening
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these (non-)assumptions could result in a different API. For example, if
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all interface modes were assumed to use the same form of rate matching,
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then a bitmask of interface modes supportting rate matching would
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suffice.
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For some better visibility into the process, the current rate matching
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mode is exposed as part of the ethtool ksettings. For the moment, only
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read access is supported. I'm not sure what userspace might want to
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configure yet (disable it altogether, disable just one mode, specify the
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mode to use, etc.). For the moment, since only pause-based rate
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adaptation support is added in the next few commits, rate matching can
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be disabled altogether by adjusting the advertisement.
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802.3 calls this feature "rate adaptation" in clause 49 (10GBASE-R) and
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"rate matching" in clause 61 (10PASS-TL and 2BASE-TS). Aquantia also calls
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this feature "rate adaptation". I chose "rate matching" because it is
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shorter, and because Russell doesn't think "adaptation" is correct in this
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context.
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Signed-off-by: Sean Anderson <sean.anderson@seco.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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Documentation/networking/ethtool-netlink.rst | 2 ++
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drivers/net/phy/phy-core.c | 21 +++++++++++++++
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drivers/net/phy/phy.c | 28 ++++++++++++++++++++
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include/linux/phy.h | 22 ++++++++++++++-
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include/uapi/linux/ethtool.h | 18 +++++++++++--
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include/uapi/linux/ethtool_netlink.h | 1 +
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net/ethtool/ioctl.c | 1 +
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net/ethtool/linkmodes.c | 5 ++++
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8 files changed, 95 insertions(+), 3 deletions(-)
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--- a/Documentation/networking/ethtool-netlink.rst
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+++ b/Documentation/networking/ethtool-netlink.rst
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@@ -418,6 +418,7 @@ Kernel response contents:
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``ETHTOOL_A_LINKMODES_DUPLEX`` u8 duplex mode
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``ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG`` u8 Master/slave port mode
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``ETHTOOL_A_LINKMODES_MASTER_SLAVE_STATE`` u8 Master/slave port state
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+ ``ETHTOOL_A_LINKMODES_RATE_MATCHING`` u8 PHY rate matching
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========================================== ====== ==========================
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For ``ETHTOOL_A_LINKMODES_OURS``, value represents advertised modes and mask
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@@ -441,6 +442,7 @@ Request contents:
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``ETHTOOL_A_LINKMODES_SPEED`` u32 link speed (Mb/s)
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``ETHTOOL_A_LINKMODES_DUPLEX`` u8 duplex mode
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``ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG`` u8 Master/slave port mode
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+ ``ETHTOOL_A_LINKMODES_RATE_MATCHING`` u8 PHY rate matching
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``ETHTOOL_A_LINKMODES_LANES`` u32 lanes
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========================================== ====== ==========================
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--- a/drivers/net/phy/phy-core.c
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+++ b/drivers/net/phy/phy-core.c
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@@ -75,6 +75,27 @@ const char *phy_duplex_to_str(unsigned i
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EXPORT_SYMBOL_GPL(phy_duplex_to_str);
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/**
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+ * phy_rate_matching_to_str - Return a string describing the rate matching
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+ *
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+ * @rate_matching: Type of rate matching to describe
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+ */
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+const char *phy_rate_matching_to_str(int rate_matching)
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+{
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+ switch (rate_matching) {
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+ case RATE_MATCH_NONE:
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+ return "none";
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+ case RATE_MATCH_PAUSE:
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+ return "pause";
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+ case RATE_MATCH_CRS:
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+ return "crs";
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+ case RATE_MATCH_OPEN_LOOP:
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+ return "open-loop";
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+ }
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+ return "Unsupported (update phy-core.c)";
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+}
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+EXPORT_SYMBOL_GPL(phy_rate_matching_to_str);
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+
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+/**
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* phy_interface_num_ports - Return the number of links that can be carried by
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* a given MAC-PHY physical link. Returns 0 if this is
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* unknown, the number of links else.
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--- a/drivers/net/phy/phy.c
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+++ b/drivers/net/phy/phy.c
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@@ -127,6 +127,33 @@ void phy_print_status(struct phy_device
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EXPORT_SYMBOL(phy_print_status);
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/**
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+ * phy_get_rate_matching - determine if rate matching is supported
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+ * @phydev: The phy device to return rate matching for
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+ * @iface: The interface mode to use
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+ *
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+ * This determines the type of rate matching (if any) that @phy supports
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+ * using @iface. @iface may be %PHY_INTERFACE_MODE_NA to determine if any
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+ * interface supports rate matching.
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+ *
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+ * Return: The type of rate matching @phy supports for @iface, or
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+ * %RATE_MATCH_NONE.
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+ */
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+int phy_get_rate_matching(struct phy_device *phydev,
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+ phy_interface_t iface)
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+{
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+ int ret = RATE_MATCH_NONE;
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+
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+ if (phydev->drv->get_rate_matching) {
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+ mutex_lock(&phydev->lock);
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+ ret = phydev->drv->get_rate_matching(phydev, iface);
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+ mutex_unlock(&phydev->lock);
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+ }
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+
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+ return ret;
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+}
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+EXPORT_SYMBOL_GPL(phy_get_rate_matching);
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+
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+/**
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* phy_config_interrupt - configure the PHY device for the requested interrupts
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* @phydev: the phy_device struct
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* @interrupts: interrupt flags to configure for this @phydev
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@@ -268,6 +295,7 @@ void phy_ethtool_ksettings_get(struct ph
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cmd->base.duplex = phydev->duplex;
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cmd->base.master_slave_cfg = phydev->master_slave_get;
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cmd->base.master_slave_state = phydev->master_slave_state;
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+ cmd->base.rate_matching = phydev->rate_matching;
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if (phydev->interface == PHY_INTERFACE_MODE_MOCA)
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cmd->base.port = PORT_BNC;
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else
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--- a/include/linux/phy.h
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+++ b/include/linux/phy.h
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@@ -280,7 +280,6 @@ static inline const char *phy_modes(phy_
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}
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}
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-
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#define PHY_INIT_TIMEOUT 100000
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#define PHY_FORCE_TIMEOUT 10
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@@ -573,6 +572,7 @@ struct macsec_ops;
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* @lp_advertising: Current link partner advertised linkmodes
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* @eee_broken_modes: Energy efficient ethernet modes which should be prohibited
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* @autoneg: Flag autoneg being used
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+ * @rate_matching: Current rate matching mode
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* @link: Current link state
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* @autoneg_complete: Flag auto negotiation of the link has completed
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* @mdix: Current crossover
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@@ -639,6 +639,8 @@ struct phy_device {
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unsigned irq_suspended:1;
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unsigned irq_rerun:1;
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+ int rate_matching;
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+
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enum phy_state state;
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u32 dev_flags;
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@@ -801,6 +803,21 @@ struct phy_driver {
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*/
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int (*get_features)(struct phy_device *phydev);
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+ /**
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+ * @get_rate_matching: Get the supported type of rate matching for a
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+ * particular phy interface. This is used by phy consumers to determine
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+ * whether to advertise lower-speed modes for that interface. It is
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+ * assumed that if a rate matching mode is supported on an interface,
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+ * then that interface's rate can be adapted to all slower link speeds
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+ * supported by the phy. If iface is %PHY_INTERFACE_MODE_NA, and the phy
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+ * supports any kind of rate matching for any interface, then it must
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+ * return that rate matching mode (preferring %RATE_MATCH_PAUSE to
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+ * %RATE_MATCH_CRS). If the interface is not supported, this should
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+ * return %RATE_MATCH_NONE.
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+ */
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+ int (*get_rate_matching)(struct phy_device *phydev,
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+ phy_interface_t iface);
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+
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/* PHY Power Management */
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/** @suspend: Suspend the hardware, saving state if needed */
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int (*suspend)(struct phy_device *phydev);
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@@ -967,6 +984,7 @@ struct phy_fixup {
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const char *phy_speed_to_str(int speed);
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const char *phy_duplex_to_str(unsigned int duplex);
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+const char *phy_rate_matching_to_str(int rate_matching);
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int phy_interface_num_ports(phy_interface_t interface);
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@@ -1675,6 +1693,8 @@ int phy_disable_interrupts(struct phy_de
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void phy_request_interrupt(struct phy_device *phydev);
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void phy_free_interrupt(struct phy_device *phydev);
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void phy_print_status(struct phy_device *phydev);
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+int phy_get_rate_matching(struct phy_device *phydev,
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+ phy_interface_t iface);
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int phy_set_max_speed(struct phy_device *phydev, u32 max_speed);
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void phy_remove_link_mode(struct phy_device *phydev, u32 link_mode);
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void phy_advertise_supported(struct phy_device *phydev);
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--- a/include/uapi/linux/ethtool.h
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+++ b/include/uapi/linux/ethtool.h
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@@ -1809,6 +1809,20 @@ static inline int ethtool_validate_duple
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#define MASTER_SLAVE_STATE_SLAVE 3
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#define MASTER_SLAVE_STATE_ERR 4
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+/* These are used to throttle the rate of data on the phy interface when the
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+ * native speed of the interface is higher than the link speed. These should
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+ * not be used for phy interfaces which natively support multiple speeds (e.g.
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+ * MII or SGMII).
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+ */
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+/* No rate matching performed. */
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+#define RATE_MATCH_NONE 0
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+/* The phy sends pause frames to throttle the MAC. */
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+#define RATE_MATCH_PAUSE 1
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+/* The phy asserts CRS to prevent the MAC from transmitting. */
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+#define RATE_MATCH_CRS 2
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+/* The MAC is programmed with a sufficiently-large IPG. */
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+#define RATE_MATCH_OPEN_LOOP 3
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+
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/* Which connector port. */
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#define PORT_TP 0x00
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#define PORT_AUI 0x01
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@@ -2002,8 +2016,8 @@ enum ethtool_reset_flags {
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* reported consistently by PHYLIB. Read-only.
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* @master_slave_cfg: Master/slave port mode.
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* @master_slave_state: Master/slave port state.
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+ * @rate_matching: Rate adaptation performed by the PHY
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* @reserved: Reserved for future use; see the note on reserved space.
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- * @reserved1: Reserved for future use; see the note on reserved space.
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* @link_mode_masks: Variable length bitmaps.
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*
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* If autonegotiation is disabled, the speed and @duplex represent the
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@@ -2054,7 +2068,7 @@ struct ethtool_link_settings {
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__u8 transceiver;
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__u8 master_slave_cfg;
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__u8 master_slave_state;
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- __u8 reserved1[1];
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+ __u8 rate_matching;
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__u32 reserved[7];
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__u32 link_mode_masks[0];
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/* layout of link_mode_masks fields:
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--- a/include/uapi/linux/ethtool_netlink.h
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+++ b/include/uapi/linux/ethtool_netlink.h
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@@ -238,6 +238,7 @@ enum {
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ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG, /* u8 */
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ETHTOOL_A_LINKMODES_MASTER_SLAVE_STATE, /* u8 */
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ETHTOOL_A_LINKMODES_LANES, /* u32 */
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+ ETHTOOL_A_LINKMODES_RATE_MATCHING, /* u8 */
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/* add new constants above here */
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__ETHTOOL_A_LINKMODES_CNT,
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--- a/net/ethtool/ioctl.c
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+++ b/net/ethtool/ioctl.c
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@@ -559,6 +559,7 @@ static int ethtool_get_link_ksettings(st
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= __ETHTOOL_LINK_MODE_MASK_NU32;
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link_ksettings.base.master_slave_cfg = MASTER_SLAVE_CFG_UNSUPPORTED;
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link_ksettings.base.master_slave_state = MASTER_SLAVE_STATE_UNSUPPORTED;
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+ link_ksettings.base.rate_matching = RATE_MATCH_NONE;
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return store_link_ksettings_for_user(useraddr, &link_ksettings);
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}
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--- a/net/ethtool/linkmodes.c
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+++ b/net/ethtool/linkmodes.c
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@@ -70,6 +70,7 @@ static int linkmodes_reply_size(const st
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+ nla_total_size(sizeof(u32)) /* LINKMODES_SPEED */
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+ nla_total_size(sizeof(u32)) /* LINKMODES_LANES */
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+ nla_total_size(sizeof(u8)) /* LINKMODES_DUPLEX */
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+ + nla_total_size(sizeof(u8)) /* LINKMODES_RATE_MATCHING */
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+ 0;
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ret = ethnl_bitset_size(ksettings->link_modes.advertising,
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ksettings->link_modes.supported,
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@@ -143,6 +144,10 @@ static int linkmodes_fill_reply(struct s
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lsettings->master_slave_state))
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return -EMSGSIZE;
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+ if (nla_put_u8(skb, ETHTOOL_A_LINKMODES_RATE_MATCHING,
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+ lsettings->rate_matching))
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+ return -EMSGSIZE;
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+
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return 0;
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}
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