net: ethtool: netlink: retrieve stats from multiple sources (eMAC, pMAC)

IEEE 802.3-2018 clause 99 defines a MAC Merge sublayer which contains an
Express MAC and a Preemptible MAC. Both MACs are hidden to higher and
lower layers and visible as a single MAC (packet classification to eMAC
or pMAC on TX is done based on priority; classification on RX is done
based on SFD).

For devices which support a MAC Merge sublayer, it is desirable to
retrieve individual packet counters from the eMAC and the pMAC, as well
as aggregate statistics (their sum).

Introduce a new ETHTOOL_A_STATS_SRC attribute which is part of the
policy of ETHTOOL_MSG_STATS_GET and, and an ETHTOOL_A_PAUSE_STATS_SRC
which is part of the policy of ETHTOOL_MSG_PAUSE_GET (accepted when
ETHTOOL_FLAG_STATS is set in the common ethtool header). Both of these
take values from enum ethtool_mac_stats_src, defaulting to "aggregate"
in the absence of the attribute.

Existing drivers do not need to pay attention to this enum which was
added to all driver-facing structures, just the ones which report the
MAC merge layer as supported.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/ethtool.h

@@ -311,6 +311,7 @@ static inline void ethtool_stats_init(u64 *stats, unsigned int n)
  * via a more targeted API.
  */
 struct ethtool_eth_mac_stats {
+	enum ethtool_mac_stats_src src;
 	u64 FramesTransmittedOK;
 	u64 SingleCollisionFrames;
 	u64 MultipleCollisionFrames;
@@ -339,6 +340,7 @@ struct ethtool_eth_mac_stats {
  * via a more targeted API.
  */
 struct ethtool_eth_phy_stats {
+	enum ethtool_mac_stats_src src;
 	u64 SymbolErrorDuringCarrier;
 };
 
@@ -346,6 +348,7 @@ struct ethtool_eth_phy_stats {
  * via a more targeted API.
  */
 struct ethtool_eth_ctrl_stats {
+	enum ethtool_mac_stats_src src;
 	u64 MACControlFramesTransmitted;
 	u64 MACControlFramesReceived;
 	u64 UnsupportedOpcodesReceived;
@@ -353,6 +356,8 @@ struct ethtool_eth_ctrl_stats {
 
 /**
  * struct ethtool_pause_stats - statistics for IEEE 802.3x pause frames
+ * @src: input field denoting whether stats should be queried from the eMAC or
+ *	pMAC (if the MM layer is supported). To be ignored otherwise.
  * @tx_pause_frames: transmitted pause frame count. Reported to user space
  *	as %ETHTOOL_A_PAUSE_STAT_TX_FRAMES.
  *
@@ -366,6 +371,7 @@ struct ethtool_eth_ctrl_stats {
  *	from the standard.
  */
 struct ethtool_pause_stats {
+	enum ethtool_mac_stats_src src;
 	u64 tx_pause_frames;
 	u64 rx_pause_frames;
 };
@@ -417,6 +423,8 @@ struct ethtool_rmon_hist_range {
 
 /**
  * struct ethtool_rmon_stats - selected RMON (RFC 2819) statistics
+ * @src: input field denoting whether stats should be queried from the eMAC or
+ *	pMAC (if the MM layer is supported). To be ignored otherwise.
  * @undersize_pkts: Equivalent to `etherStatsUndersizePkts` from the RFC.
  * @oversize_pkts: Equivalent to `etherStatsOversizePkts` from the RFC.
  * @fragments: Equivalent to `etherStatsFragments` from the RFC.
@@ -432,6 +440,7 @@ struct ethtool_rmon_hist_range {
  * ranges is left to the driver.
  */
 struct ethtool_rmon_stats {
+	enum ethtool_mac_stats_src src;
 	u64 undersize_pkts;
 	u64 oversize_pkts;
 	u64 fragments;

include/uapi/linux/ethtool.h

@@ -711,6 +711,24 @@ enum ethtool_stringset {
 	ETH_SS_COUNT
 };
 
+/**
+ * enum ethtool_mac_stats_src - source of ethtool MAC statistics
+ * @ETHTOOL_MAC_STATS_SRC_AGGREGATE:
+ *	if device supports a MAC merge layer, this retrieves the aggregate
+ *	statistics of the eMAC and pMAC. Otherwise, it retrieves just the
+ *	statistics of the single (express) MAC.
+ * @ETHTOOL_MAC_STATS_SRC_EMAC:
+ *	if device supports a MM layer, this retrieves the eMAC statistics.
+ *	Otherwise, it retrieves the statistics of the single (express) MAC.
+ * @ETHTOOL_MAC_STATS_SRC_PMAC:
+ *	if device supports a MM layer, this retrieves the pMAC statistics.
+ */
+enum ethtool_mac_stats_src {
+	ETHTOOL_MAC_STATS_SRC_AGGREGATE,
+	ETHTOOL_MAC_STATS_SRC_EMAC,
+	ETHTOOL_MAC_STATS_SRC_PMAC,
+};
+
 /**
  * enum ethtool_module_power_mode_policy - plug-in module power mode policy
  * @ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH: Module is always in high power mode.

include/uapi/linux/ethtool_netlink.h

@@ -428,6 +428,7 @@ enum {
 	ETHTOOL_A_PAUSE_RX,				/* u8 */
 	ETHTOOL_A_PAUSE_TX,				/* u8 */
 	ETHTOOL_A_PAUSE_STATS,				/* nest - _PAUSE_STAT_* */
+	ETHTOOL_A_PAUSE_STATS_SRC,			/* u32 */
 
 	/* add new constants above here */
 	__ETHTOOL_A_PAUSE_CNT,
@@ -744,6 +745,8 @@ enum {
 
 	ETHTOOL_A_STATS_GRP,			/* nest - _A_STATS_GRP_* */
 
+	ETHTOOL_A_STATS_SRC,			/* u32 */
+
 	/* add new constants above here */
 	__ETHTOOL_A_STATS_CNT,
 	ETHTOOL_A_STATS_MAX = (__ETHTOOL_A_STATS_CNT - 1)

net/ethtool/common.h

@@ -54,4 +54,6 @@ int ethtool_get_module_info_call(struct net_device *dev,
 int ethtool_get_module_eeprom_call(struct net_device *dev,
 				   struct ethtool_eeprom *ee, u8 *data);
 
+bool __ethtool_dev_mm_supported(struct net_device *dev);
+
 #endif /* _ETHTOOL_COMMON_H */

net/ethtool/mm.c

@@ -253,3 +253,19 @@ int ethnl_set_mm(struct sk_buff *skb, struct genl_info *info)
 	ethnl_parse_header_dev_put(&req_info);
 	return ret;
 }
+
+/* Returns whether a given device supports the MAC merge layer
+ * (has an eMAC and a pMAC). Must be called under rtnl_lock() and
+ * ethnl_ops_begin().
+ */
+bool __ethtool_dev_mm_supported(struct net_device *dev)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct ethtool_mm_state state = {};
+	int ret = -EOPNOTSUPP;
+
+	if (ops && ops->get_mm)
+		ret = ops->get_mm(dev, &state);
+
+	return !!ret;
+}

net/ethtool/netlink.h

@@ -373,7 +373,7 @@ extern const struct nla_policy ethnl_channels_get_policy[ETHTOOL_A_CHANNELS_HEAD
 extern const struct nla_policy ethnl_channels_set_policy[ETHTOOL_A_CHANNELS_COMBINED_COUNT + 1];
 extern const struct nla_policy ethnl_coalesce_get_policy[ETHTOOL_A_COALESCE_HEADER + 1];
 extern const struct nla_policy ethnl_coalesce_set_policy[ETHTOOL_A_COALESCE_MAX + 1];
-extern const struct nla_policy ethnl_pause_get_policy[ETHTOOL_A_PAUSE_HEADER + 1];
+extern const struct nla_policy ethnl_pause_get_policy[ETHTOOL_A_PAUSE_STATS_SRC + 1];
 extern const struct nla_policy ethnl_pause_set_policy[ETHTOOL_A_PAUSE_TX + 1];
 extern const struct nla_policy ethnl_eee_get_policy[ETHTOOL_A_EEE_HEADER + 1];
 extern const struct nla_policy ethnl_eee_set_policy[ETHTOOL_A_EEE_TX_LPI_TIMER + 1];
@@ -384,7 +384,7 @@ extern const struct nla_policy ethnl_tunnel_info_get_policy[ETHTOOL_A_TUNNEL_INF
 extern const struct nla_policy ethnl_fec_get_policy[ETHTOOL_A_FEC_HEADER + 1];
 extern const struct nla_policy ethnl_fec_set_policy[ETHTOOL_A_FEC_AUTO + 1];
 extern const struct nla_policy ethnl_module_eeprom_get_policy[ETHTOOL_A_MODULE_EEPROM_I2C_ADDRESS + 1];
-extern const struct nla_policy ethnl_stats_get_policy[ETHTOOL_A_STATS_GROUPS + 1];
+extern const struct nla_policy ethnl_stats_get_policy[ETHTOOL_A_STATS_SRC + 1];
 extern const struct nla_policy ethnl_phc_vclocks_get_policy[ETHTOOL_A_PHC_VCLOCKS_HEADER + 1];
 extern const struct nla_policy ethnl_module_get_policy[ETHTOOL_A_MODULE_HEADER + 1];
 extern const struct nla_policy ethnl_module_set_policy[ETHTOOL_A_MODULE_POWER_MODE_POLICY + 1];

net/ethtool/pause.c

@@ -5,8 +5,12 @@
 
 struct pause_req_info {
 	struct ethnl_req_info		base;
+	enum ethtool_mac_stats_src	src;
 };
 
+#define PAUSE_REQINFO(__req_base) \
+	container_of(__req_base, struct pause_req_info, base)
+
 struct pause_reply_data {
 	struct ethnl_reply_data		base;
 	struct ethtool_pauseparam	pauseparam;
@@ -19,13 +23,40 @@ struct pause_reply_data {
 const struct nla_policy ethnl_pause_get_policy[] = {
 	[ETHTOOL_A_PAUSE_HEADER]		=
 		NLA_POLICY_NESTED(ethnl_header_policy_stats),
+	[ETHTOOL_A_PAUSE_STATS_SRC]		=
+		NLA_POLICY_MAX(NLA_U32, ETHTOOL_MAC_STATS_SRC_PMAC),
 };
 
+static int pause_parse_request(struct ethnl_req_info *req_base,
+			       struct nlattr **tb,
+			       struct netlink_ext_ack *extack)
+{
+	enum ethtool_mac_stats_src src = ETHTOOL_MAC_STATS_SRC_AGGREGATE;
+	struct pause_req_info *req_info = PAUSE_REQINFO(req_base);
+
+	if (tb[ETHTOOL_A_PAUSE_STATS_SRC]) {
+		if (!(req_base->flags & ETHTOOL_FLAG_STATS)) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "ETHTOOL_FLAG_STATS must be set when requesting a source of stats");
+			return -EINVAL;
+		}
+
+		src = nla_get_u32(tb[ETHTOOL_A_PAUSE_STATS_SRC]);
+	}
+
+	req_info->src = src;
+
+	return 0;
+}
+
 static int pause_prepare_data(const struct ethnl_req_info *req_base,
 			      struct ethnl_reply_data *reply_base,
 			      struct genl_info *info)
 {
+	const struct pause_req_info *req_info = PAUSE_REQINFO(req_base);
 	struct pause_reply_data *data = PAUSE_REPDATA(reply_base);
+	enum ethtool_mac_stats_src src = req_info->src;
+	struct netlink_ext_ack *extack = info->extack;
 	struct net_device *dev = reply_base->dev;
 	int ret;
 
@@ -34,14 +65,26 @@ static int pause_prepare_data(const struct ethnl_req_info *req_base,
 
 	ethtool_stats_init((u64 *)&data->pausestat,
 			   sizeof(data->pausestat) / 8);
+	data->pausestat.src = src;
 
 	ret = ethnl_ops_begin(dev);
 	if (ret < 0)
 		return ret;
+
+	if ((src == ETHTOOL_MAC_STATS_SRC_EMAC ||
+	     src == ETHTOOL_MAC_STATS_SRC_PMAC) &&
+	    !__ethtool_dev_mm_supported(dev)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Device does not support MAC merge layer");
+		ethnl_ops_complete(dev);
+		return -EOPNOTSUPP;
+	}
+
 	dev->ethtool_ops->get_pauseparam(dev, &data->pauseparam);
 	if (req_base->flags & ETHTOOL_FLAG_STATS &&
 	    dev->ethtool_ops->get_pause_stats)
 		dev->ethtool_ops->get_pause_stats(dev, &data->pausestat);
+
 	ethnl_ops_complete(dev);
 
 	return 0;
@@ -56,6 +99,7 @@ static int pause_reply_size(const struct ethnl_req_info *req_base,
 
 	if (req_base->flags & ETHTOOL_FLAG_STATS)
 		n += nla_total_size(0) +	/* _PAUSE_STATS */
+		     nla_total_size(sizeof(u32)) + /* _PAUSE_STATS_SRC */
 		     nla_total_size_64bit(sizeof(u64)) * ETHTOOL_PAUSE_STAT_CNT;
 	return n;
 }
@@ -77,6 +121,9 @@ static int pause_put_stats(struct sk_buff *skb,
 	const u16 pad = ETHTOOL_A_PAUSE_STAT_PAD;
 	struct nlattr *nest;
 
+	if (nla_put_u32(skb, ETHTOOL_A_PAUSE_STATS_SRC, pause_stats->src))
+		return -EMSGSIZE;
+
 	nest = nla_nest_start(skb, ETHTOOL_A_PAUSE_STATS);
 	if (!nest)
 		return -EMSGSIZE;
@@ -121,6 +168,7 @@ const struct ethnl_request_ops ethnl_pause_request_ops = {
 	.req_info_size		= sizeof(struct pause_req_info),
 	.reply_data_size	= sizeof(struct pause_reply_data),
 
+	.parse_request		= pause_parse_request,
 	.prepare_data		= pause_prepare_data,
 	.reply_size		= pause_reply_size,
 	.fill_reply		= pause_fill_reply,

net/ethtool/stats.c

@@ -7,6 +7,7 @@
 struct stats_req_info {
 	struct ethnl_req_info		base;
 	DECLARE_BITMAP(stat_mask, __ETHTOOL_STATS_CNT);
+	enum ethtool_mac_stats_src	src;
 };
 
 #define STATS_REQINFO(__req_base) \
@@ -75,16 +76,19 @@ const char stats_rmon_names[__ETHTOOL_A_STATS_RMON_CNT][ETH_GSTRING_LEN] = {
 	[ETHTOOL_A_STATS_RMON_JABBER]		= "etherStatsJabbers",
 };
 
-const struct nla_policy ethnl_stats_get_policy[ETHTOOL_A_STATS_GROUPS + 1] = {
+const struct nla_policy ethnl_stats_get_policy[ETHTOOL_A_STATS_SRC + 1] = {
 	[ETHTOOL_A_STATS_HEADER]	=
 		NLA_POLICY_NESTED(ethnl_header_policy),
 	[ETHTOOL_A_STATS_GROUPS]	= { .type = NLA_NESTED },
+	[ETHTOOL_A_STATS_SRC]		=
+		NLA_POLICY_MAX(NLA_U32, ETHTOOL_MAC_STATS_SRC_PMAC),
 };
 
 static int stats_parse_request(struct ethnl_req_info *req_base,
 			       struct nlattr **tb,
 			       struct netlink_ext_ack *extack)
 {
+	enum ethtool_mac_stats_src src = ETHTOOL_MAC_STATS_SRC_AGGREGATE;
 	struct stats_req_info *req_info = STATS_REQINFO(req_base);
 	bool mod = false;
 	int err;
@@ -100,6 +104,11 @@ static int stats_parse_request(struct ethnl_req_info *req_base,
 		return -EINVAL;
 	}
 
+	if (tb[ETHTOOL_A_STATS_SRC])
+		src = nla_get_u32(tb[ETHTOOL_A_STATS_SRC]);
+
+	req_info->src = src;
+
 	return 0;
 }
 
@@ -109,6 +118,8 @@ static int stats_prepare_data(const struct ethnl_req_info *req_base,
 {
 	const struct stats_req_info *req_info = STATS_REQINFO(req_base);
 	struct stats_reply_data *data = STATS_REPDATA(reply_base);
+	enum ethtool_mac_stats_src src = req_info->src;
+	struct netlink_ext_ack *extack = info->extack;
 	struct net_device *dev = reply_base->dev;
 	int ret;
 
@@ -116,11 +127,25 @@ static int stats_prepare_data(const struct ethnl_req_info *req_base,
 	if (ret < 0)
 		return ret;
 
+	if ((src == ETHTOOL_MAC_STATS_SRC_EMAC ||
+	     src == ETHTOOL_MAC_STATS_SRC_PMAC) &&
+	    !__ethtool_dev_mm_supported(dev)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Device does not support MAC merge layer");
+		ethnl_ops_complete(dev);
+		return -EOPNOTSUPP;
+	}
+
 	/* Mark all stats as unset (see ETHTOOL_STAT_NOT_SET) to prevent them
 	 * from being reported to user space in case driver did not set them.
 	 */
 	memset(&data->stats, 0xff, sizeof(data->stats));
 
+	data->phy_stats.src = src;
+	data->mac_stats.src = src;
+	data->ctrl_stats.src = src;
+	data->rmon_stats.src = src;
+
 	if (test_bit(ETHTOOL_STATS_ETH_PHY, req_info->stat_mask) &&
 	    dev->ethtool_ops->get_eth_phy_stats)
 		dev->ethtool_ops->get_eth_phy_stats(dev, &data->phy_stats);
@@ -146,6 +171,8 @@ static int stats_reply_size(const struct ethnl_req_info *req_base,
 	unsigned int n_grps = 0, n_stats = 0;
 	int len = 0;
 
+	len += nla_total_size(sizeof(u32)); /* _STATS_SRC */
+
 	if (test_bit(ETHTOOL_STATS_ETH_PHY, req_info->stat_mask)) {
 		n_stats += sizeof(struct ethtool_eth_phy_stats) / sizeof(u64);
 		n_grps++;
@@ -379,6 +406,9 @@ static int stats_fill_reply(struct sk_buff *skb,
 	const struct stats_reply_data *data = STATS_REPDATA(reply_base);
 	int ret = 0;
 
+	if (nla_put_u32(skb, ETHTOOL_A_STATS_SRC, req_info->src))
+		return -EMSGSIZE;
+
 	if (!ret && test_bit(ETHTOOL_STATS_ETH_PHY, req_info->stat_mask))
 		ret = stats_put_stats(skb, data, ETHTOOL_STATS_ETH_PHY,
 				      ETH_SS_STATS_ETH_PHY,