ethtool: add interface to read Tx hardware timestamping statistics

Multiple network devices that support hardware timestamping appear to have
common behavior with regards to timestamp handling. Implement common Tx
hardware timestamping statistics in a tx_stats struct_group. Common Rx
hardware timestamping statistics can subsequently be implemented in a
rx_stats struct_group for ethtool_ts_stats.

Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Link: https://lore.kernel.org/r/20240403212931.128541-2-rrameshbabu@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 51 insertions, 1 deletions

diff --git a/net/ethtool/tsinfo.c b/net/ethtool/tsinfo.c
index 9daed0aab162..be2755c8d8fd 100644
--- a/net/ethtool/tsinfo.c
+++ b/net/ethtool/tsinfo.c
@@ -13,14 +13,18 @@ struct tsinfo_req_info {
 struct tsinfo_reply_data {
 	struct ethnl_reply_data		base;
 	struct ethtool_ts_info		ts_info;
+	struct ethtool_ts_stats		stats;
 };
 
 #define TSINFO_REPDATA(__reply_base) \
 	container_of(__reply_base, struct tsinfo_reply_data, base)
 
+#define ETHTOOL_TS_STAT_CNT \
+	(__ETHTOOL_A_TS_STAT_CNT - (ETHTOOL_A_TS_STAT_UNSPEC + 1))
+
 const struct nla_policy ethnl_tsinfo_get_policy[] = {
 	[ETHTOOL_A_TSINFO_HEADER]		=
-		NLA_POLICY_NESTED(ethnl_header_policy),
+		NLA_POLICY_NESTED(ethnl_header_policy_stats),
 };
 
 static int tsinfo_prepare_data(const struct ethnl_req_info *req_base,
@@ -34,6 +38,12 @@ static int tsinfo_prepare_data(const struct ethnl_req_info *req_base,
 	ret = ethnl_ops_begin(dev);
 	if (ret < 0)
 		return ret;
+	if (req_base->flags & ETHTOOL_FLAG_STATS &&
+	    dev->ethtool_ops->get_ts_stats) {
+		ethtool_stats_init((u64 *)&data->stats,
+				   sizeof(data->stats) / sizeof(u64));
+		dev->ethtool_ops->get_ts_stats(dev, &data->stats);
+	}
 	ret = __ethtool_get_ts_info(dev, &data->ts_info);
 	ethnl_ops_complete(dev);
 
@@ -79,10 +89,47 @@ static int tsinfo_reply_size(const struct ethnl_req_info *req_base,
 	}
 	if (ts_info->phc_index >= 0)
 		len += nla_total_size(sizeof(u32));	/* _TSINFO_PHC_INDEX */
+	if (req_base->flags & ETHTOOL_FLAG_STATS)
+		len += nla_total_size(0) + /* _TSINFO_STATS */
+		       nla_total_size_64bit(sizeof(u64)) * ETHTOOL_TS_STAT_CNT;
 
 	return len;
 }
 
+static int tsinfo_put_stat(struct sk_buff *skb, u64 val, u16 attrtype)
+{
+	if (val == ETHTOOL_STAT_NOT_SET)
+		return 0;
+	if (nla_put_uint(skb, attrtype, val))
+		return -EMSGSIZE;
+	return 0;
+}
+
+static int tsinfo_put_stats(struct sk_buff *skb,
+			    const struct ethtool_ts_stats *stats)
+{
+	struct nlattr *nest;
+
+	nest = nla_nest_start(skb, ETHTOOL_A_TSINFO_STATS);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (tsinfo_put_stat(skb, stats->tx_stats.pkts,
+			    ETHTOOL_A_TS_STAT_TX_PKTS) ||
+	    tsinfo_put_stat(skb, stats->tx_stats.lost,
+			    ETHTOOL_A_TS_STAT_TX_LOST) ||
+	    tsinfo_put_stat(skb, stats->tx_stats.err,
+			    ETHTOOL_A_TS_STAT_TX_ERR))
+		goto err_cancel;
+
+	nla_nest_end(skb, nest);
+	return 0;
+
+err_cancel:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
+}
+
 static int tsinfo_fill_reply(struct sk_buff *skb,
 			     const struct ethnl_req_info *req_base,
 			     const struct ethnl_reply_data *reply_base)
@@ -119,6 +166,9 @@ static int tsinfo_fill_reply(struct sk_buff *skb,
 	if (ts_info->phc_index >= 0 &&
 	    nla_put_u32(skb, ETHTOOL_A_TSINFO_PHC_INDEX, ts_info->phc_index))
 		return -EMSGSIZE;
+	if (req_base->flags & ETHTOOL_FLAG_STATS &&
+	    tsinfo_put_stats(skb, &data->stats))
+		return -EMSGSIZE;
 
 	return 0;
 }