From bf8fc60a62db3fa99d2ded50e68bf3e5be027ebe Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Wed, 12 Feb 2014 22:13:57 +0000 Subject: [PATCH] ethtool: Expand documentation of struct ethtool_cmd struct ethtool_cmd has very limited documentation; it contains several obscure or obsolete fields and several with non-obvious interpretation. Replace the inline comments (and some others below) with a full explanation of the semantics as well as I understand them, in kernel-doc format. Formally deprecate some fields that seem to be of historical use only. Extend the comment about 32/64-bit compatibility to cover all ethtool structures. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- include/uapi/linux/ethtool.h | 124 +++++++++++++++++++++++++---------- 1 file changed, 90 insertions(+), 34 deletions(-) diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h index 38dbafaa5341..c4d5eb2bfac5 100644 --- a/include/uapi/linux/ethtool.h +++ b/include/uapi/linux/ethtool.h @@ -16,37 +16,97 @@ #include #include -/* This should work for both 32 and 64 bit userland. */ +/* All structures exposed to userland should be defined such that they + * have the same layout for 32-bit and 64-bit userland. + */ + +/** + * struct ethtool_cmd - link control and status + * @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 + * interface supports autonegotiation or auto-detection. + * Read-only. + * @advertising: Bitmask of %ADVERTISED_* flags for the link modes, + * physical connectors and other link features that are + * advertised through autonegotiation or enabled for + * auto-detection. + * @speed: Low bits of the speed + * @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. + * @transceiver: Historically used to distinguish different possible + * PHY types, but not in a consistent way. Deprecated. + * @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. + * @maxtxpkt: Historically used to report TX IRQ coalescing; now + * obsoleted by &struct ethtool_coalesce. Read-only; deprecated. + * @maxrxpkt: Historically used to report RX IRQ coalescing; now + * obsoleted by &struct ethtool_coalesce. Read-only; deprecated. + * @speed_hi: High bits of the speed + * @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. + * @lp_advertising: Bitmask of %ADVERTISED_* flags for the link modes + * and other link features that the link partner advertised + * through autonegotiation; 0 if unknown or not applicable. + * Read-only. + * + * The link speed in Mbps is split between @speed and @speed_hi. Use + * the ethtool_cmd_speed() and ethtool_cmd_speed_set() functions to + * access it. + * + * 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. + * + * Users should assume that all fields not marked read-only are + * writable and subject to validation by the driver. They should use + * %ETHTOOL_GSET to get the current values before making specific + * changes and then applying them with %ETHTOOL_SSET. + * + * Drivers that implement set_settings() should validate all fields + * other than @cmd that are not described as read-only or deprecated, + * and must ignore all fields described as read-only. + * + * Deprecated fields should be ignored by both users and drivers. + */ struct ethtool_cmd { __u32 cmd; - __u32 supported; /* Features this interface supports */ - __u32 advertising; /* Features this interface advertises */ - __u16 speed; /* The forced speed (lower bits) in - * Mbps. Please use - * ethtool_cmd_speed()/_set() to - * access it */ - __u8 duplex; /* Duplex, half or full */ - __u8 port; /* Which connector port */ - __u8 phy_address; /* MDIO PHY address (PRTAD for clause 45). - * May be read-only or read-write - * depending on the driver. - */ - __u8 transceiver; /* Which transceiver to use */ - __u8 autoneg; /* Enable or disable autonegotiation */ - __u8 mdio_support; /* MDIO protocols supported. Read-only. - * Not set by all drivers. - */ - __u32 maxtxpkt; /* Tx pkts before generating tx int */ - __u32 maxrxpkt; /* Rx pkts before generating rx int */ - __u16 speed_hi; /* The forced speed (upper - * bits) in Mbps. Please use - * ethtool_cmd_speed()/_set() to - * access it */ - __u8 eth_tp_mdix; /* twisted pair MDI-X status */ - __u8 eth_tp_mdix_ctrl; /* twisted pair MDI-X control, when set, - * link should be renegotiated if necessary - */ - __u32 lp_advertising; /* Features the link partner advertises */ + __u32 supported; + __u32 advertising; + __u16 speed; + __u8 duplex; + __u8 port; + __u8 phy_address; + __u8 transceiver; + __u8 autoneg; + __u8 mdio_support; + __u32 maxtxpkt; + __u32 maxrxpkt; + __u16 speed_hi; + __u8 eth_tp_mdix; + __u8 eth_tp_mdix_ctrl; + __u32 lp_advertising; __u32 reserved[2]; }; @@ -905,7 +965,6 @@ enum ethtool_sfeatures_retval_bits { #define SPARC_ETH_GSET ETHTOOL_GSET #define SPARC_ETH_SSET ETHTOOL_SSET -/* Indicates what features are supported by the interface. */ #define SUPPORTED_10baseT_Half (1 << 0) #define SUPPORTED_10baseT_Full (1 << 1) #define SUPPORTED_100baseT_Half (1 << 2) @@ -934,7 +993,6 @@ enum ethtool_sfeatures_retval_bits { #define SUPPORTED_40000baseSR4_Full (1 << 25) #define SUPPORTED_40000baseLR4_Full (1 << 26) -/* Indicates what features are advertised by the interface. */ #define ADVERTISED_10baseT_Half (1 << 0) #define ADVERTISED_10baseT_Full (1 << 1) #define ADVERTISED_100baseT_Half (1 << 2) @@ -999,9 +1057,7 @@ enum ethtool_sfeatures_retval_bits { #define XCVR_DUMMY2 0x03 #define XCVR_DUMMY3 0x04 -/* Enable or disable autonegotiation. If this is set to enable, - * the forced link modes above are completely ignored. - */ +/* Enable or disable autonegotiation. */ #define AUTONEG_DISABLE 0x00 #define AUTONEG_ENABLE 0x01