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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 <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Ben Hutchings 2014-02-12 22:13:57 +00:00 committed by David S. Miller
parent 738b52bb98
commit bf8fc60a62
1 changed files with 90 additions and 34 deletions

View File

@ -16,37 +16,97 @@
#include <linux/types.h>
#include <linux/if_ether.h>
/* 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