[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <1392243237.15615.5.camel@deadeye.wl.decadent.org.uk>
Date: Wed, 12 Feb 2014 22:13:57 +0000
From: Ben Hutchings <ben@...adent.org.uk>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org
Subject: [PATCH net-next 01/14] 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@...adent.org.uk>
---
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 38dbafa..c4d5eb2 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -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
--
Ben Hutchings
If more than one person is responsible for a bug, no one is at fault.
Download attachment "signature.asc" of type "application/pgp-signature" (812 bytes)
Powered by blists - more mailing lists