net: Introduce new feature setting ops

This introduces a new framework to handle device features setting.
It consists of:
  - new fields in struct net_device:
	+ hw_features - features that hw/driver supports toggling
	+ wanted_features - features that user wants enabled, when possible
  - new netdev_ops:
	+ feat = ndo_fix_features(dev, feat) - API checking constraints for
		enabling features or their combinations
	+ ndo_set_features(dev) - API updating hardware state to match
		changed dev->features
  - new ethtool commands:
	+ ETHTOOL_GFEATURES/ETHTOOL_SFEATURES: get/set dev->wanted_features
		and trigger device reconfiguration if resulting dev->features
		changed
	+ ETHTOOL_GSTRINGS(ETH_SS_FEATURES): get feature bits names (meaning)

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 85 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 1908929204a9..806e716bb4fb 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -251,6 +251,7 @@ enum ethtool_stringset {
         ETH_SS_STATS,
         ETH_SS_PRIV_FLAGS,
         ETH_SS_NTUPLE_FILTERS,
+        ETH_SS_FEATURES,
 };
 
 /* for passing string sets for data tagging */
@@ -523,6 +524,87 @@ struct ethtool_flash {
         char    data[ETHTOOL_FLASH_MAX_FILENAME];
 };
 
+/* for returning and changing feature sets */
+
+/**
+ * struct ethtool_get_features_block - block with state of 32 features
+ * @available: mask of changeable features
+ * @requested: mask of features requested to be enabled if possible
+ * @active: mask of currently enabled features
+ * @never_changed: mask of features not changeable for any device
+ */
+struct ethtool_get_features_block {
+        __u32   available;
+        __u32   requested;
+        __u32   active;
+        __u32   never_changed;
+};
+
+/**
+ * struct ethtool_gfeatures - command to get state of device's features
+ * @cmd: command number = %ETHTOOL_GFEATURES
+ * @size: in: number of elements in the features[] array;
+ *       out: number of elements in features[] needed to hold all features
+ * @features: state of features
+ */
+struct ethtool_gfeatures {
+        __u32   cmd;
+        __u32   size;
+        struct ethtool_get_features_block features[0];
+};
+
+/**
+ * struct ethtool_set_features_block - block with request for 32 features
+ * @valid: mask of features to be changed
+ * @requested: values of features to be changed
+ */
+struct ethtool_set_features_block {
+        __u32   valid;
+        __u32   requested;
+};
+
+/**
+ * struct ethtool_sfeatures - command to request change in device's features
+ * @cmd: command number = %ETHTOOL_SFEATURES
+ * @size: array size of the features[] array
+ * @features: feature change masks
+ */
+struct ethtool_sfeatures {
+        __u32   cmd;
+        __u32   size;
+        struct ethtool_set_features_block features[0];
+};
+
+/*
+ * %ETHTOOL_SFEATURES changes features present in features[].valid to the
+ * values of corresponding bits in features[].requested. Bits in .requested
+ * not set in .valid or not changeable are ignored.
+ *
+ * Returns %EINVAL when .valid contains undefined or never-changable bits
+ * or size is not equal to required number of features words (32-bit blocks).
+ * Returns >= 0 if request was completed; bits set in the value mean:
+ *   %ETHTOOL_F_UNSUPPORTED - there were bits set in .valid that are not
+ *      changeable (not present in %ETHTOOL_GFEATURES' features[].available)
+ *      those bits were ignored.
+ *   %ETHTOOL_F_WISH - some or all changes requested were recorded but the
+ *      resulting state of bits masked by .valid is not equal to .requested.
+ *      Probably there are other device-specific constraints on some features
+ *      in the set. When %ETHTOOL_F_UNSUPPORTED is set, .valid is considered
+ *      here as though ignored bits were cleared.
+ *
+ * Meaning of bits in the masks are obtained by %ETHTOOL_GSSET_INFO (number of
+ * bits in the arrays - always multiple of 32) and %ETHTOOL_GSTRINGS commands
+ * for ETH_SS_FEATURES string set. First entry in the table corresponds to least
+ * significant bit in features[0] fields. Empty strings mark undefined features.
+ */
+enum ethtool_sfeatures_retval_bits {
+        ETHTOOL_F_UNSUPPORTED__BIT,
+        ETHTOOL_F_WISH__BIT,
+};
+
+#define ETHTOOL_F_UNSUPPORTED   (1 << ETHTOOL_F_UNSUPPORTED__BIT)
+#define ETHTOOL_F_WISH          (1 << ETHTOOL_F_WISH__BIT)
+
 #ifdef __KERNEL__
 
 #include <linux/rculist.h>
@@ -744,6 +826,9 @@ struct ethtool_ops {
 #define ETHTOOL_GRXFHINDIR      0x00000038 /* Get RX flow hash indir'n table */
 #define ETHTOOL_SRXFHINDIR      0x00000039 /* Set RX flow hash indir'n table */
 
+#define ETHTOOL_GFEATURES       0x0000003a /* Get device offload settings */
+#define ETHTOOL_SFEATURES       0x0000003b /* Change device offload settings */
+
 /* compatibility with older code */
 #define SPARC_ETH_GSET          ETHTOOL_GSET
 #define SPARC_ETH_SSET          ETHTOOL_SSET