net: ethtool: add new ETHTOOL_xLINKSETTINGS API

This patch defines a new ETHTOOL_GLINKSETTINGS/SLINKSETTINGS API,
handled by the new get_link_ksettings/set_link_ksettings callbacks.
This API provides support for most legacy ethtool_cmd fields, adds
support for larger link mode masks (up to 4064 bits, variable length),
and removes ethtool_cmd deprecated
fields (transceiver/maxrxpkt/maxtxpkt).

This API is deprecating the legacy ETHTOOL_GSET/SSET API and provides
the following backward compatibility properties:
 - legacy ethtool with legacy drivers: no change, still using the
   get_settings/set_settings callbacks.
 - legacy ethtool with new get/set_link_ksettings drivers: the new
   driver callbacks are used, data internally converted to legacy
   ethtool_cmd. ETHTOOL_GSET will return only the 1st 32b of each link
   mode mask. ETHTOOL_SSET will fail if user tries to set the
   ethtool_cmd deprecated fields to
   non-0 (transceiver/maxrxpkt/maxtxpkt). A kernel warning is logged if
   driver sets higher bits.
 - future ethtool with legacy drivers: no change, still using the
   get_settings/set_settings callbacks, internally converted to new data
   structure. Deprecated fields (transceiver/maxrxpkt/maxtxpkt) will be
   ignored and seen as 0 from user space. Note that that "future"
   ethtool tool will not allow changes to these deprecated fields.
 - future ethtool with new drivers: direct call to the new callbacks.

By "future" ethtool, what is meant is:
 - query: first try ETHTOOL_GLINKSETTINGS, and revert to ETHTOOL_GSET if
   fails
 - set: query first and remember which of ETHTOOL_GLINKSETTINGS or
   ETHTOOL_GSET was successful
   + if ETHTOOL_GLINKSETTINGS was successful, then change config with
     ETHTOOL_SLINKSETTINGS. A failure there is final (do not try
     ETHTOOL_SSET).
   + otherwise ETHTOOL_GSET was successful, change config with
     ETHTOOL_SSET. A failure there is final (do not try
     ETHTOOL_SLINKSETTINGS).

The interaction user/kernel via the new API requires a small
ETHTOOL_GLINKSETTINGS handshake first to agree on the length of the link
mode bitmaps. If kernel doesn't agree with user, it returns the bitmap
length it is expecting from user as a negative length (and cmd field is
0). When kernel and user agree, kernel returns valid info in all
fields (ie. link mode length > 0 and cmd is ETHTOOL_GLINKSETTINGS).

Data structure crossing user/kernel boundary is 32/64-bit
agnostic. Converted internally to a legal kernel bitmap.

The internal __ethtool_get_settings kernel helper will gradually be
replaced by __ethtool_get_link_ksettings by the time the first
"link_settings" drivers start to appear. So this patch doesn't change
it, it will be removed before it needs to be changed.

Signed-off-by: David Decotigny <decot@googlers.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 256 insertions, 66 deletions

diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index f15ae02621a1..37fd6dc33de4 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -21,7 +21,8 @@
  */
 
 /**
- * struct ethtool_cmd - link control and status
+ * struct ethtool_cmd - DEPRECATED, link control and status
+ * This structure is DEPRECATED, please use struct ethtool_link_settings.
  * @cmd: Command number = %ETHTOOL_GSET or %ETHTOOL_SSET
  * @supported: Bitmask of %SUPPORTED_* flags for the link modes,
  *	physical connectors and other link features for which the
@@ -1219,8 +1220,12 @@ struct ethtool_per_queue_op {
 };
 
 /* CMDs currently supported */
-#define ETHTOOL_GSET		0x00000001 /* Get settings. */
-#define ETHTOOL_SSET		0x00000002 /* Set settings. */
+#define ETHTOOL_GSET		0x00000001 /* DEPRECATED, Get settings.
+					    * Please use ETHTOOL_GLINKSETTINGS
+					    */
+#define ETHTOOL_SSET		0x00000002 /* DEPRECATED, Set settings.
+					    * Please use ETHTOOL_SLINKSETTINGS
+					    */
 #define ETHTOOL_GDRVINFO	0x00000003 /* Get driver info. */
 #define ETHTOOL_GREGS		0x00000004 /* Get NIC registers. */
 #define ETHTOOL_GWOL		0x00000005 /* Get wake-on-lan options. */
@@ -1302,73 +1307,139 @@ struct ethtool_per_queue_op {
 
 #define ETHTOOL_PERQUEUE	0x0000004b /* Set per queue options */
 
+#define ETHTOOL_GLINKSETTINGS	0x0000004c /* Get ethtool_link_settings */
+#define ETHTOOL_SLINKSETTINGS	0x0000004d /* Set ethtool_link_settings */
+
+
 /* compatibility with older code */
 #define SPARC_ETH_GSET		ETHTOOL_GSET
 #define SPARC_ETH_SSET		ETHTOOL_SSET
 
-#define SUPPORTED_10baseT_Half		(1 << 0)
-#define SUPPORTED_10baseT_Full		(1 << 1)
-#define SUPPORTED_100baseT_Half		(1 << 2)
-#define SUPPORTED_100baseT_Full		(1 << 3)
-#define SUPPORTED_1000baseT_Half	(1 << 4)
-#define SUPPORTED_1000baseT_Full	(1 << 5)
-#define SUPPORTED_Autoneg		(1 << 6)
-#define SUPPORTED_TP			(1 << 7)
-#define SUPPORTED_AUI			(1 << 8)
-#define SUPPORTED_MII			(1 << 9)
-#define SUPPORTED_FIBRE			(1 << 10)
-#define SUPPORTED_BNC			(1 << 11)
-#define SUPPORTED_10000baseT_Full	(1 << 12)
-#define SUPPORTED_Pause			(1 << 13)
-#define SUPPORTED_Asym_Pause		(1 << 14)
-#define SUPPORTED_2500baseX_Full	(1 << 15)
-#define SUPPORTED_Backplane		(1 << 16)
-#define SUPPORTED_1000baseKX_Full	(1 << 17)
-#define SUPPORTED_10000baseKX4_Full	(1 << 18)
-#define SUPPORTED_10000baseKR_Full	(1 << 19)
-#define SUPPORTED_10000baseR_FEC	(1 << 20)
-#define SUPPORTED_20000baseMLD2_Full	(1 << 21)
-#define SUPPORTED_20000baseKR2_Full	(1 << 22)
-#define SUPPORTED_40000baseKR4_Full	(1 << 23)
-#define SUPPORTED_40000baseCR4_Full	(1 << 24)
-#define SUPPORTED_40000baseSR4_Full	(1 << 25)
-#define SUPPORTED_40000baseLR4_Full	(1 << 26)
-#define SUPPORTED_56000baseKR4_Full	(1 << 27)
-#define SUPPORTED_56000baseCR4_Full	(1 << 28)
-#define SUPPORTED_56000baseSR4_Full	(1 << 29)
-#define SUPPORTED_56000baseLR4_Full	(1 << 30)
-
-#define ADVERTISED_10baseT_Half		(1 << 0)
-#define ADVERTISED_10baseT_Full		(1 << 1)
-#define ADVERTISED_100baseT_Half	(1 << 2)
-#define ADVERTISED_100baseT_Full	(1 << 3)
-#define ADVERTISED_1000baseT_Half	(1 << 4)
-#define ADVERTISED_1000baseT_Full	(1 << 5)
-#define ADVERTISED_Autoneg		(1 << 6)
-#define ADVERTISED_TP			(1 << 7)
-#define ADVERTISED_AUI			(1 << 8)
-#define ADVERTISED_MII			(1 << 9)
-#define ADVERTISED_FIBRE		(1 << 10)
-#define ADVERTISED_BNC			(1 << 11)
-#define ADVERTISED_10000baseT_Full	(1 << 12)
-#define ADVERTISED_Pause		(1 << 13)
-#define ADVERTISED_Asym_Pause		(1 << 14)
-#define ADVERTISED_2500baseX_Full	(1 << 15)
-#define ADVERTISED_Backplane		(1 << 16)
-#define ADVERTISED_1000baseKX_Full	(1 << 17)
-#define ADVERTISED_10000baseKX4_Full	(1 << 18)
-#define ADVERTISED_10000baseKR_Full	(1 << 19)
-#define ADVERTISED_10000baseR_FEC	(1 << 20)
-#define ADVERTISED_20000baseMLD2_Full	(1 << 21)
-#define ADVERTISED_20000baseKR2_Full	(1 << 22)
-#define ADVERTISED_40000baseKR4_Full	(1 << 23)
-#define ADVERTISED_40000baseCR4_Full	(1 << 24)
-#define ADVERTISED_40000baseSR4_Full	(1 << 25)
-#define ADVERTISED_40000baseLR4_Full	(1 << 26)
-#define ADVERTISED_56000baseKR4_Full	(1 << 27)
-#define ADVERTISED_56000baseCR4_Full	(1 << 28)
-#define ADVERTISED_56000baseSR4_Full	(1 << 29)
-#define ADVERTISED_56000baseLR4_Full	(1 << 30)
+/* Link mode bit indices */
+enum ethtool_link_mode_bit_indices {
+	ETHTOOL_LINK_MODE_10baseT_Half_BIT	= 0,
+	ETHTOOL_LINK_MODE_10baseT_Full_BIT	= 1,
+	ETHTOOL_LINK_MODE_100baseT_Half_BIT	= 2,
+	ETHTOOL_LINK_MODE_100baseT_Full_BIT	= 3,
+	ETHTOOL_LINK_MODE_1000baseT_Half_BIT	= 4,
+	ETHTOOL_LINK_MODE_1000baseT_Full_BIT	= 5,
+	ETHTOOL_LINK_MODE_Autoneg_BIT		= 6,
+	ETHTOOL_LINK_MODE_TP_BIT		= 7,
+	ETHTOOL_LINK_MODE_AUI_BIT		= 8,
+	ETHTOOL_LINK_MODE_MII_BIT		= 9,
+	ETHTOOL_LINK_MODE_FIBRE_BIT		= 10,
+	ETHTOOL_LINK_MODE_BNC_BIT		= 11,
+	ETHTOOL_LINK_MODE_10000baseT_Full_BIT	= 12,
+	ETHTOOL_LINK_MODE_Pause_BIT		= 13,
+	ETHTOOL_LINK_MODE_Asym_Pause_BIT	= 14,
+	ETHTOOL_LINK_MODE_2500baseX_Full_BIT	= 15,
+	ETHTOOL_LINK_MODE_Backplane_BIT		= 16,
+	ETHTOOL_LINK_MODE_1000baseKX_Full_BIT	= 17,
+	ETHTOOL_LINK_MODE_10000baseKX4_Full_BIT	= 18,
+	ETHTOOL_LINK_MODE_10000baseKR_Full_BIT	= 19,
+	ETHTOOL_LINK_MODE_10000baseR_FEC_BIT	= 20,
+	ETHTOOL_LINK_MODE_20000baseMLD2_Full_BIT = 21,
+	ETHTOOL_LINK_MODE_20000baseKR2_Full_BIT	= 22,
+	ETHTOOL_LINK_MODE_40000baseKR4_Full_BIT	= 23,
+	ETHTOOL_LINK_MODE_40000baseCR4_Full_BIT	= 24,
+	ETHTOOL_LINK_MODE_40000baseSR4_Full_BIT	= 25,
+	ETHTOOL_LINK_MODE_40000baseLR4_Full_BIT	= 26,
+	ETHTOOL_LINK_MODE_56000baseKR4_Full_BIT	= 27,
+	ETHTOOL_LINK_MODE_56000baseCR4_Full_BIT	= 28,
+	ETHTOOL_LINK_MODE_56000baseSR4_Full_BIT	= 29,
+	ETHTOOL_LINK_MODE_56000baseLR4_Full_BIT	= 30,
+
+	/* Last allowed bit for __ETHTOOL_LINK_MODE_LEGACY_MASK is bit
+	 * 31. Please do NOT define any SUPPORTED_* or ADVERTISED_*
+	 * macro for bits > 31. The only way to use indices > 31 is to
+	 * use the new ETHTOOL_GLINKSETTINGS/ETHTOOL_SLINKSETTINGS API.
+	 */
+
+	__ETHTOOL_LINK_MODE_LAST
+	  = ETHTOOL_LINK_MODE_56000baseLR4_Full_BIT,
+};
+
+#define __ETHTOOL_LINK_MODE_LEGACY_MASK(base_name)	\
+	(1UL << (ETHTOOL_LINK_MODE_ ## base_name ## _BIT))
+
+/* DEPRECATED macros. Please migrate to
+ * ETHTOOL_GLINKSETTINGS/ETHTOOL_SLINKSETTINGS API. Please do NOT
+ * define any new SUPPORTED_* macro for bits > 31.
+ */
+#define SUPPORTED_10baseT_Half		__ETHTOOL_LINK_MODE_LEGACY_MASK(10baseT_Half)
+#define SUPPORTED_10baseT_Full		__ETHTOOL_LINK_MODE_LEGACY_MASK(10baseT_Full)
+#define SUPPORTED_100baseT_Half		__ETHTOOL_LINK_MODE_LEGACY_MASK(100baseT_Half)
+#define SUPPORTED_100baseT_Full		__ETHTOOL_LINK_MODE_LEGACY_MASK(100baseT_Full)
+#define SUPPORTED_1000baseT_Half	__ETHTOOL_LINK_MODE_LEGACY_MASK(1000baseT_Half)
+#define SUPPORTED_1000baseT_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(1000baseT_Full)
+#define SUPPORTED_Autoneg		__ETHTOOL_LINK_MODE_LEGACY_MASK(Autoneg)
+#define SUPPORTED_TP			__ETHTOOL_LINK_MODE_LEGACY_MASK(TP)
+#define SUPPORTED_AUI			__ETHTOOL_LINK_MODE_LEGACY_MASK(AUI)
+#define SUPPORTED_MII			__ETHTOOL_LINK_MODE_LEGACY_MASK(MII)
+#define SUPPORTED_FIBRE			__ETHTOOL_LINK_MODE_LEGACY_MASK(FIBRE)
+#define SUPPORTED_BNC			__ETHTOOL_LINK_MODE_LEGACY_MASK(BNC)
+#define SUPPORTED_10000baseT_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(10000baseT_Full)
+#define SUPPORTED_Pause			__ETHTOOL_LINK_MODE_LEGACY_MASK(Pause)
+#define SUPPORTED_Asym_Pause		__ETHTOOL_LINK_MODE_LEGACY_MASK(Asym_Pause)
+#define SUPPORTED_2500baseX_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(2500baseX_Full)
+#define SUPPORTED_Backplane		__ETHTOOL_LINK_MODE_LEGACY_MASK(Backplane)
+#define SUPPORTED_1000baseKX_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(1000baseKX_Full)
+#define SUPPORTED_10000baseKX4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(10000baseKX4_Full)
+#define SUPPORTED_10000baseKR_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(10000baseKR_Full)
+#define SUPPORTED_10000baseR_FEC	__ETHTOOL_LINK_MODE_LEGACY_MASK(10000baseR_FEC)
+#define SUPPORTED_20000baseMLD2_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(20000baseMLD2_Full)
+#define SUPPORTED_20000baseKR2_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(20000baseKR2_Full)
+#define SUPPORTED_40000baseKR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(40000baseKR4_Full)
+#define SUPPORTED_40000baseCR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(40000baseCR4_Full)
+#define SUPPORTED_40000baseSR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(40000baseSR4_Full)
+#define SUPPORTED_40000baseLR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(40000baseLR4_Full)
+#define SUPPORTED_56000baseKR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(56000baseKR4_Full)
+#define SUPPORTED_56000baseCR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(56000baseCR4_Full)
+#define SUPPORTED_56000baseSR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(56000baseSR4_Full)
+#define SUPPORTED_56000baseLR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(56000baseLR4_Full)
+/* Please do not define any new SUPPORTED_* macro for bits > 31, see
+ * notice above.
+ */
+
+/*
+ * DEPRECATED macros. Please migrate to
+ * ETHTOOL_GLINKSETTINGS/ETHTOOL_SLINKSETTINGS API. Please do NOT
+ * define any new ADERTISE_* macro for bits > 31.
+ */
+#define ADVERTISED_10baseT_Half		__ETHTOOL_LINK_MODE_LEGACY_MASK(10baseT_Half)
+#define ADVERTISED_10baseT_Full		__ETHTOOL_LINK_MODE_LEGACY_MASK(10baseT_Full)
+#define ADVERTISED_100baseT_Half	__ETHTOOL_LINK_MODE_LEGACY_MASK(100baseT_Half)
+#define ADVERTISED_100baseT_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(100baseT_Full)
+#define ADVERTISED_1000baseT_Half	__ETHTOOL_LINK_MODE_LEGACY_MASK(1000baseT_Half)
+#define ADVERTISED_1000baseT_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(1000baseT_Full)
+#define ADVERTISED_Autoneg		__ETHTOOL_LINK_MODE_LEGACY_MASK(Autoneg)
+#define ADVERTISED_TP			__ETHTOOL_LINK_MODE_LEGACY_MASK(TP)
+#define ADVERTISED_AUI			__ETHTOOL_LINK_MODE_LEGACY_MASK(AUI)
+#define ADVERTISED_MII			__ETHTOOL_LINK_MODE_LEGACY_MASK(MII)
+#define ADVERTISED_FIBRE		__ETHTOOL_LINK_MODE_LEGACY_MASK(FIBRE)
+#define ADVERTISED_BNC			__ETHTOOL_LINK_MODE_LEGACY_MASK(BNC)
+#define ADVERTISED_10000baseT_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(10000baseT_Full)
+#define ADVERTISED_Pause		__ETHTOOL_LINK_MODE_LEGACY_MASK(Pause)
+#define ADVERTISED_Asym_Pause		__ETHTOOL_LINK_MODE_LEGACY_MASK(Asym_Pause)
+#define ADVERTISED_2500baseX_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(2500baseX_Full)
+#define ADVERTISED_Backplane		__ETHTOOL_LINK_MODE_LEGACY_MASK(Backplane)
+#define ADVERTISED_1000baseKX_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(1000baseKX_Full)
+#define ADVERTISED_10000baseKX4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(10000baseKX4_Full)
+#define ADVERTISED_10000baseKR_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(10000baseKR_Full)
+#define ADVERTISED_10000baseR_FEC	__ETHTOOL_LINK_MODE_LEGACY_MASK(10000baseR_FEC)
+#define ADVERTISED_20000baseMLD2_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(20000baseMLD2_Full)
+#define ADVERTISED_20000baseKR2_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(20000baseKR2_Full)
+#define ADVERTISED_40000baseKR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(40000baseKR4_Full)
+#define ADVERTISED_40000baseCR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(40000baseCR4_Full)
+#define ADVERTISED_40000baseSR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(40000baseSR4_Full)
+#define ADVERTISED_40000baseLR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(40000baseLR4_Full)
+#define ADVERTISED_56000baseKR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(56000baseKR4_Full)
+#define ADVERTISED_56000baseCR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(56000baseCR4_Full)
+#define ADVERTISED_56000baseSR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(56000baseSR4_Full)
+#define ADVERTISED_56000baseLR4_Full	__ETHTOOL_LINK_MODE_LEGACY_MASK(56000baseLR4_Full)
+/* Please do not define any new ADVERTISED_* macro for bits > 31, see
+ * notice above.
+ */
 
 /* The following are all involved in forcing a particular link
  * mode for the device for setting things.  When getting the
@@ -1533,4 +1604,123 @@ enum ethtool_reset_flags {
 };
 #define ETH_RESET_SHARED_SHIFT	16
 
+
+/**
+ * struct ethtool_link_settings - link control and status
+ *
+ * IMPORTANT, Backward compatibility notice: When implementing new
+ *	user-space tools, please first try %ETHTOOL_GLINKSETTINGS, and
+ *	if it succeeds use %ETHTOOL_SLINKSETTINGS to change link
+ *	settings; do not use %ETHTOOL_SSET if %ETHTOOL_GLINKSETTINGS
+ *	succeeded: stick to %ETHTOOL_GLINKSETTINGS/%SLINKSETTINGS in
+ *	that case.  Conversely, if %ETHTOOL_GLINKSETTINGS fails, use
+ *	%ETHTOOL_GSET to query and %ETHTOOL_SSET to change link
+ *	settings; do not use %ETHTOOL_SLINKSETTINGS if
+ *	%ETHTOOL_GLINKSETTINGS failed: stick to
+ *	%ETHTOOL_GSET/%ETHTOOL_SSET in that case.
+ *
+ * @cmd: Command number = %ETHTOOL_GLINKSETTINGS or %ETHTOOL_SLINKSETTINGS
+ * @speed: Link speed (Mbps)
+ * @duplex: Duplex mode; one of %DUPLEX_*
+ * @port: Physical connector type; one of %PORT_*
+ * @phy_address: MDIO address of PHY (transceiver); 0 or 255 if not
+ *	applicable.  For clause 45 PHYs this is the PRTAD.
+ * @autoneg: Enable/disable autonegotiation and auto-detection;
+ *	either %AUTONEG_DISABLE or %AUTONEG_ENABLE
+ * @mdio_support: Bitmask of %ETH_MDIO_SUPPORTS_* flags for the MDIO
+ *	protocols supported by the interface; 0 if unknown.
+ *	Read-only.
+ * @eth_tp_mdix: Ethernet twisted-pair MDI(-X) status; one of
+ *	%ETH_TP_MDI_*.  If the status is unknown or not applicable, the
+ *	value will be %ETH_TP_MDI_INVALID.  Read-only.
+ * @eth_tp_mdix_ctrl: Ethernet twisted pair MDI(-X) control; one of
+ *	%ETH_TP_MDI_*.  If MDI(-X) control is not implemented, reads
+ *	yield %ETH_TP_MDI_INVALID and writes may be ignored or rejected.
+ *	When written successfully, the link should be renegotiated if
+ *	necessary.
+ * @link_mode_masks_nwords: Number of 32-bit words for each of the
+ *	supported, advertising, lp_advertising link mode bitmaps. For
+ *	%ETHTOOL_GLINKSETTINGS: on entry, number of words passed by user
+ *	(>= 0); on return, if handshake in progress, negative if
+ *	request size unsupported by kernel: absolute value indicates
+ *	kernel recommended size and cmd field is 0, as well as all the
+ *	other fields; otherwise (handshake completed), strictly
+ *	positive to indicate size used by kernel and cmd field is
+ *	%ETHTOOL_GLINKSETTINGS, all other fields populated by driver. For
+ *	%ETHTOOL_SLINKSETTINGS: must be valid on entry, ie. a positive
+ *	value returned previously by %ETHTOOL_GLINKSETTINGS, otherwise
+ *	refused. For drivers: ignore this field (use kernel's
+ *	__ETHTOOL_LINK_MODE_MASK_NBITS instead), any change to it will
+ *	be overwritten by kernel.
+ * @supported: Bitmap with each bit meaning given by
+ *	%ethtool_link_mode_bit_indices for the link modes, physical
+ *	connectors and other link features for which the interface
+ *	supports autonegotiation or auto-detection.  Read-only.
+ * @advertising: Bitmap with each bit meaning given by
+ *	%ethtool_link_mode_bit_indices for the link modes, physical
+ *	connectors and other link features that are advertised through
+ *	autonegotiation or enabled for auto-detection.
+ * @lp_advertising: Bitmap with each bit meaning given by
+ *	%ethtool_link_mode_bit_indices for the link modes, and other
+ *	link features that the link partner advertised through
+ *	autonegotiation; 0 if unknown or not applicable.  Read-only.
+ *
+ * If autonegotiation is disabled, the speed and @duplex represent the
+ * fixed link mode and are writable if the driver supports multiple
+ * link modes.  If it is enabled then they are read-only; if the link
+ * is up they represent the negotiated link mode; if the link is down,
+ * the speed is 0, %SPEED_UNKNOWN or the highest enabled speed and
+ * @duplex is %DUPLEX_UNKNOWN or the best enabled duplex mode.
+ *
+ * Some hardware interfaces may have multiple PHYs and/or physical
+ * connectors fitted or do not allow the driver to detect which are
+ * fitted.  For these interfaces @port and/or @phy_address may be
+ * writable, possibly dependent on @autoneg being %AUTONEG_DISABLE.
+ * Otherwise, attempts to write different values may be ignored or
+ * rejected.
+ *
+ * Deprecated %ethtool_cmd fields transceiver, maxtxpkt and maxrxpkt
+ * are not available in %ethtool_link_settings. Until all drivers are
+ * converted to ignore them or to the new %ethtool_link_settings API,
+ * for both queries and changes, users should always try
+ * %ETHTOOL_GLINKSETTINGS first, and if it fails with -ENOTSUPP stick
+ * only to %ETHTOOL_GSET and %ETHTOOL_SSET consistently. If it
+ * succeeds, then users should stick to %ETHTOOL_GLINKSETTINGS and
+ * %ETHTOOL_SLINKSETTINGS (which would support drivers implementing
+ * either %ethtool_cmd or %ethtool_link_settings).
+ *
+ * Users should assume that all fields not marked read-only are
+ * writable and subject to validation by the driver.  They should use
+ * %ETHTOOL_GLINKSETTINGS to get the current values before making specific
+ * changes and then applying them with %ETHTOOL_SLINKSETTINGS.
+ *
+ * Drivers that implement %get_link_ksettings and/or
+ * %set_link_ksettings should ignore the @cmd
+ * and @link_mode_masks_nwords fields (any change to them overwritten
+ * by kernel), and rely only on kernel's internal
+ * %__ETHTOOL_LINK_MODE_MASK_NBITS and
+ * %ethtool_link_mode_mask_t. Drivers that implement
+ * %set_link_ksettings() should validate all fields other than @cmd
+ * and @link_mode_masks_nwords that are not described as read-only or
+ * deprecated, and must ignore all fields described as read-only.
+ */
+struct ethtool_link_settings {
+	__u32	cmd;
+	__u32	speed;
+	__u8	duplex;
+	__u8	port;
+	__u8	phy_address;
+	__u8	autoneg;
+	__u8	mdio_support;
+	__u8	eth_tp_mdix;
+	__u8	eth_tp_mdix_ctrl;
+	__s8	link_mode_masks_nwords;
+	__u32	reserved[8];
+	__u32	link_mode_masks[0];
+	/* layout of link_mode_masks fields:
+	 * __u32 map_supported[link_mode_masks_nwords];
+	 * __u32 map_advertising[link_mode_masks_nwords];
+	 * __u32 map_lp_advertising[link_mode_masks_nwords];
+	 */
+};
 #endif /* _UAPI_LINUX_ETHTOOL_H */