Merge branch 'ehtool-fec-stats'

Jakub Kicinski says:

====================
ethtool: add standard FEC statistics

This set adds uAPI for reporting standard FEC statistics, and
implements it in a handful of drivers.

The statistics are taken from the IEEE standard, with one
extra seemingly popular but not standard statistics added.

The implementation is similar to that of the pause frame
statistics, user requests the stats by setting a bit
(ETHTOOL_FLAG_STATS) in the common ethtool header of
ETHTOOL_MSG_FEC_GET.

Since standard defines the statistics per lane what's
reported is both total and per-lane counters:

 # ethtool -I --show-fec eth0
 FEC parameters for eth0:
 Configured FEC encodings: None
 Active FEC encoding: None
 Statistics:
  corrected_blocks: 256
    Lane 0: 255
    Lane 1: 1
  uncorrectable_blocks: 145
    Lane 0: 128
    Lane 1: 17

v2: check for errors in mlx5 register access
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 46 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 9f6f323af59a..112a85b57f1f 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -244,6 +244,12 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
 
 #define ETHTOOL_STAT_NOT_SET	(~0ULL)
 
+static inline void ethtool_stats_init(u64 *stats, unsigned int n)
+{
+	while (n--)
+		stats[n] = ETHTOOL_STAT_NOT_SET;
+}
+
 /**
  * struct ethtool_pause_stats - statistics for IEEE 802.3x pause frames
  * @tx_pause_frames: transmitted pause frame count. Reported to user space
@@ -263,6 +269,39 @@ struct ethtool_pause_stats {
 	u64 rx_pause_frames;
 };
 
+#define ETHTOOL_MAX_LANES	8
+
+/**
+ * struct ethtool_fec_stats - statistics for IEEE 802.3 FEC
+ * @corrected_blocks: number of received blocks corrected by FEC
+ *	Reported to user space as %ETHTOOL_A_FEC_STAT_CORRECTED.
+ *
+ *	Equivalent to `30.5.1.1.17 aFECCorrectedBlocks` from the standard.
+ *
+ * @uncorrectable_blocks: number of received blocks FEC was not able to correct
+ *	Reported to user space as %ETHTOOL_A_FEC_STAT_UNCORR.
+ *
+ *	Equivalent to `30.5.1.1.18 aFECUncorrectableBlocks` from the standard.
+ *
+ * @corrected_bits: number of bits corrected by FEC
+ *	Similar to @corrected_blocks but counts individual bit changes,
+ *	not entire FEC data blocks. This is a non-standard statistic.
+ *	Reported to user space as %ETHTOOL_A_FEC_STAT_CORR_BITS.
+ *
+ * @lane: per-lane/PCS-instance counts as defined by the standard
+ * @total: error counts for the entire port, for drivers incapable of reporting
+ *	per-lane stats
+ *
+ * Drivers should fill in either only total or per-lane statistics, core
+ * will take care of adding lane values up to produce the total.
+ */
+struct ethtool_fec_stats {
+	struct ethtool_fec_stat {
+		u64 total;
+		u64 lanes[ETHTOOL_MAX_LANES];
+	} corrected_blocks, uncorrectable_blocks, corrected_bits;
+};
+
 #define ETH_MODULE_EEPROM_PAGE_LEN	128
 #define ETH_MODULE_MAX_I2C_ADDRESS	0x7f
 
@@ -433,6 +472,11 @@ struct ethtool_module_eeprom {
  *	ignored (use %__ETHTOOL_LINK_MODE_MASK_NBITS instead of the latter),
  *	any change to them will be overwritten by kernel. Returns a negative
  *	error code or zero.
+ * @get_fec_stats: Report FEC statistics.
+ *	Core will sum up per-lane stats to get the total.
+ *	Drivers must not zero statistics which they don't report. The stats
+ *	structure is initialized to ETHTOOL_STAT_NOT_SET indicating driver does
+ *	not report statistics.
  * @get_fecparam: Get the network device Forward Error Correction parameters.
  * @set_fecparam: Set the network device Forward Error Correction parameters.
  * @get_ethtool_phy_stats: Return extended statistics about the PHY device.
@@ -538,6 +582,8 @@ struct ethtool_ops {
 				      struct ethtool_link_ksettings *);
 	int	(*set_link_ksettings)(struct net_device *,
 				      const struct ethtool_link_ksettings *);
+	void	(*get_fec_stats)(struct net_device *dev,
+				 struct ethtool_fec_stats *fec_stats);
 	int	(*get_fecparam)(struct net_device *,
 				      struct ethtool_fecparam *);
 	int	(*set_fecparam)(struct net_device *,