nfp: abm: report statistics from RED offload

Report basic and extended RED statistics back to TC.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/abm/ctrl.c

@@ -44,8 +44,15 @@
 
 #define NFP_QLVL_SYM_NAME	"_abi_nfd_out_q_lvls_%u"
 #define NFP_QLVL_STRIDE		16
+#define NFP_QLVL_BLOG_BYTES	0
+#define NFP_QLVL_BLOG_PKTS	4
 #define NFP_QLVL_THRS		8
 
+#define NFP_QMSTAT_SYM_NAME	"_abi_nfdqm%u_stats"
+#define NFP_QMSTAT_STRIDE	32
+#define NFP_QMSTAT_DROP		16
+#define NFP_QMSTAT_ECN		24
+
 static unsigned long long
 nfp_abm_q_lvl_thrs(struct nfp_abm_link *alink, unsigned int queue)
 {
@@ -53,6 +60,55 @@ nfp_abm_q_lvl_thrs(struct nfp_abm_link *alink, unsigned int queue)
 		(alink->queue_base + queue) * NFP_QLVL_STRIDE + NFP_QLVL_THRS;
 }
 
+static int
+nfp_abm_ctrl_stat(struct nfp_abm_link *alink, const struct nfp_rtsym *sym,
+		  unsigned int stride, unsigned int offset, unsigned int i,
+		  bool is_u64, u64 *res)
+{
+	struct nfp_cpp *cpp = alink->abm->app->cpp;
+	u32 val32, mur;
+	u64 val, addr;
+	int err;
+
+	mur = NFP_CPP_ATOMIC_RD(sym->target, sym->domain);
+
+	addr = sym->addr + (alink->queue_base + i) * stride + offset;
+	if (is_u64)
+		err = nfp_cpp_readq(cpp, mur, addr, &val);
+	else
+		err = nfp_cpp_readl(cpp, mur, addr, &val32);
+	if (err) {
+		nfp_err(cpp,
+			"RED offload reading stat failed on vNIC %d queue %d\n",
+			alink->id, i);
+		return err;
+	}
+
+	*res = is_u64 ? val : val32;
+	return 0;
+}
+
+static int
+nfp_abm_ctrl_stat_all(struct nfp_abm_link *alink, const struct nfp_rtsym *sym,
+		      unsigned int stride, unsigned int offset, bool is_u64,
+		      u64 *res)
+{
+	u64 val, sum = 0;
+	unsigned int i;
+	int err;
+
+	for (i = 0; i < alink->vnic->max_rx_rings; i++) {
+		err = nfp_abm_ctrl_stat(alink, sym, stride, offset, i,
+					is_u64, &val);
+		if (err)
+			return err;
+		sum += val;
+	}
+
+	*res = sum;
+	return 0;
+}
+
 static int
 nfp_abm_ctrl_set_q_lvl(struct nfp_abm_link *alink, unsigned int i, u32 val)
 {
@@ -86,6 +142,58 @@ int nfp_abm_ctrl_set_all_q_lvls(struct nfp_abm_link *alink, u32 val)
 	return 0;
 }
 
+int nfp_abm_ctrl_read_stats(struct nfp_abm_link *alink,
+			    struct nfp_alink_stats *stats)
+{
+	u64 pkts = 0, bytes = 0;
+	int i, err;
+
+	for (i = 0; i < alink->vnic->max_rx_rings; i++) {
+		pkts += nn_readq(alink->vnic, NFP_NET_CFG_RXR_STATS(i));
+		bytes += nn_readq(alink->vnic, NFP_NET_CFG_RXR_STATS(i) + 8);
+	}
+	stats->tx_pkts = pkts;
+	stats->tx_bytes = bytes;
+
+	err = nfp_abm_ctrl_stat_all(alink, alink->abm->q_lvls,
+				    NFP_QLVL_STRIDE, NFP_QLVL_BLOG_BYTES,
+				    false, &stats->backlog_bytes);
+	if (err)
+		return err;
+
+	err = nfp_abm_ctrl_stat_all(alink, alink->abm->q_lvls,
+				    NFP_QLVL_STRIDE, NFP_QLVL_BLOG_PKTS,
+				    false, &stats->backlog_pkts);
+	if (err)
+		return err;
+
+	err = nfp_abm_ctrl_stat_all(alink, alink->abm->qm_stats,
+				    NFP_QMSTAT_STRIDE, NFP_QMSTAT_DROP,
+				    true, &stats->drops);
+	if (err)
+		return err;
+
+	return nfp_abm_ctrl_stat_all(alink, alink->abm->qm_stats,
+				     NFP_QMSTAT_STRIDE, NFP_QMSTAT_ECN,
+				     true, &stats->overlimits);
+}
+
+int nfp_abm_ctrl_read_xstats(struct nfp_abm_link *alink,
+			     struct nfp_alink_xstats *xstats)
+{
+	int err;
+
+	err = nfp_abm_ctrl_stat_all(alink, alink->abm->qm_stats,
+				    NFP_QMSTAT_STRIDE, NFP_QMSTAT_DROP,
+				    true, &xstats->pdrop);
+	if (err)
+		return err;
+
+	return nfp_abm_ctrl_stat_all(alink, alink->abm->qm_stats,
+				     NFP_QMSTAT_STRIDE, NFP_QMSTAT_ECN,
+				     true, &xstats->ecn_marked);
+}
+
 int nfp_abm_ctrl_qm_enable(struct nfp_abm *abm)
 {
 	return nfp_mbox_cmd(abm->app->pf, NFP_MBOX_PCIE_ABM_ENABLE,
@@ -147,5 +255,11 @@ int nfp_abm_ctrl_find_addrs(struct nfp_abm *abm)
 		return PTR_ERR(sym);
 	abm->q_lvls = sym;
 
+	snprintf(pf_symbol, sizeof(pf_symbol), NFP_QMSTAT_SYM_NAME, pf_id);
+	sym = nfp_abm_ctrl_find_q_rtsym(pf, pf_symbol, NFP_QMSTAT_STRIDE);
+	if (IS_ERR(sym))
+		return PTR_ERR(sym);
+	abm->qm_stats = sym;
+
 	return 0;
 }

drivers/net/ethernet/netronome/nfp/abm/main.c

@@ -40,6 +40,7 @@
 #include <linux/slab.h>
 #include <net/pkt_cls.h>
 #include <net/pkt_sched.h>
+#include <net/red.h>
 
 #include "../nfpcore/nfp.h"
 #include "../nfpcore/nfp_cpp.h"
@@ -57,6 +58,23 @@ static u32 nfp_abm_portid(enum nfp_repr_type rtype, unsigned int id)
 	       FIELD_PREP(NFP_ABM_PORTID_ID, id);
 }
 
+static int nfp_abm_reset_stats(struct nfp_abm_link *alink)
+{
+	int err;
+
+	err = nfp_abm_ctrl_read_stats(alink, &alink->qdiscs[0].stats);
+	if (err)
+		return err;
+	alink->qdiscs[0].stats.backlog_pkts = 0;
+	alink->qdiscs[0].stats.backlog_bytes = 0;
+
+	err = nfp_abm_ctrl_read_xstats(alink, &alink->qdiscs[0].xstats);
+	if (err)
+		return err;
+
+	return 0;
+}
+
 static void
 nfp_abm_red_destroy(struct net_device *netdev, struct nfp_abm_link *alink,
 		    u32 handle)
@@ -88,16 +106,86 @@ nfp_abm_red_replace(struct net_device *netdev, struct nfp_abm_link *alink,
 	if (err)
 		goto err_destroy;
 
+	/* Reset stats only on new qdisc */
+	if (alink->qdiscs[0].handle != opt->handle) {
+		err = nfp_abm_reset_stats(alink);
+		if (err)
+			goto err_destroy;
+	}
+
 	alink->qdiscs[0].handle = opt->handle;
 	port->tc_offload_cnt = 1;
 
 	return 0;
 err_destroy:
+	/* If the qdisc keeps on living, but we can't offload undo changes */
+	if (alink->qdiscs[0].handle == opt->handle) {
+		opt->set.qstats->qlen -= alink->qdiscs[0].stats.backlog_pkts;
+		opt->set.qstats->backlog -=
+			alink->qdiscs[0].stats.backlog_bytes;
+	}
 	if (alink->qdiscs[0].handle != TC_H_UNSPEC)
 		nfp_abm_red_destroy(netdev, alink, alink->qdiscs[0].handle);
 	return err;
 }
 
+static void
+nfp_abm_update_stats(struct nfp_alink_stats *new, struct nfp_alink_stats *old,
+		     struct tc_qopt_offload_stats *stats)
+{
+	_bstats_update(stats->bstats, new->tx_bytes - old->tx_bytes,
+		       new->tx_pkts - old->tx_pkts);
+	stats->qstats->qlen += new->backlog_pkts - old->backlog_pkts;
+	stats->qstats->backlog += new->backlog_bytes - old->backlog_bytes;
+	stats->qstats->overlimits += new->overlimits - old->overlimits;
+	stats->qstats->drops += new->drops - old->drops;
+}
+
+static int
+nfp_abm_red_stats(struct nfp_abm_link *alink, struct tc_red_qopt_offload *opt)
+{
+	struct nfp_alink_stats *prev_stats;
+	struct nfp_alink_stats stats;
+	int err;
+
+	if (alink->qdiscs[0].handle != opt->handle)
+		return -EOPNOTSUPP;
+	prev_stats = &alink->qdiscs[0].stats;
+
+	err = nfp_abm_ctrl_read_stats(alink, &stats);
+	if (err)
+		return err;
+
+	nfp_abm_update_stats(&stats, prev_stats, &opt->stats);
+
+	*prev_stats = stats;
+
+	return 0;
+}
+
+static int
+nfp_abm_red_xstats(struct nfp_abm_link *alink, struct tc_red_qopt_offload *opt)
+{
+	struct nfp_alink_xstats *prev_xstats;
+	struct nfp_alink_xstats xstats;
+	int err;
+
+	if (alink->qdiscs[0].handle != opt->handle)
+		return -EOPNOTSUPP;
+	prev_xstats = &alink->qdiscs[0].xstats;
+
+	err = nfp_abm_ctrl_read_xstats(alink, &xstats);
+	if (err)
+		return err;
+
+	opt->xstats->forced_mark += xstats.ecn_marked - prev_xstats->ecn_marked;
+	opt->xstats->pdrop += xstats.pdrop - prev_xstats->pdrop;
+
+	*prev_xstats = xstats;
+
+	return 0;
+}
+
 static int
 nfp_abm_setup_tc_red(struct net_device *netdev, struct nfp_abm_link *alink,
 		     struct tc_red_qopt_offload *opt)
@@ -111,6 +199,10 @@ nfp_abm_setup_tc_red(struct net_device *netdev, struct nfp_abm_link *alink,
 	case TC_RED_DESTROY:
 		nfp_abm_red_destroy(netdev, alink, opt->handle);
 		return 0;
+	case TC_RED_STATS:
+		return nfp_abm_red_stats(alink, opt);
+	case TC_RED_XSTATS:
+		return nfp_abm_red_xstats(alink, opt);
 	default:
 		return -EOPNOTSUPP;
 	}

drivers/net/ethernet/netronome/nfp/abm/main.h

@@ -50,20 +50,54 @@ struct nfp_net;
  * @eswitch_mode:	devlink eswitch mode, advanced functions only visible
  *			in switchdev mode
  * @q_lvls:	queue level control area
+ * @qm_stats:	queue statistics symbol
  */
 struct nfp_abm {
 	struct nfp_app *app;
 	unsigned int pf_id;
 	enum devlink_eswitch_mode eswitch_mode;
 	const struct nfp_rtsym *q_lvls;
+	const struct nfp_rtsym *qm_stats;
+};
+
+/**
+ * struct nfp_alink_stats - ABM NIC statistics
+ * @tx_pkts:		number of TXed packets
+ * @tx_bytes:		number of TXed bytes
+ * @backlog_pkts:	momentary backlog length (packets)
+ * @backlog_bytes:	momentary backlog length (bytes)
+ * @overlimits:		number of ECN marked TXed packets (accumulative)
+ * @drops:		number of tail-dropped packets (accumulative)
+ */
+struct nfp_alink_stats {
+	u64 tx_pkts;
+	u64 tx_bytes;
+	u64 backlog_pkts;
+	u64 backlog_bytes;
+	u64 overlimits;
+	u64 drops;
+};
+
+/**
+ * struct nfp_alink_xstats - extended ABM NIC statistics
+ * @ecn_marked:		number of ECN marked TXed packets
+ * @pdrop:		number of hard drops due to queue limit
+ */
+struct nfp_alink_xstats {
+	u64 ecn_marked;
+	u64 pdrop;
 };
 
 /**
  * struct nfp_red_qdisc - representation of single RED Qdisc
  * @handle:	handle of currently offloaded RED Qdisc
+ * @stats:	statistics from last refresh
+ * @xstats:	base of extended statistics
  */
 struct nfp_red_qdisc {
 	u32 handle;
+	struct nfp_alink_stats stats;
+	struct nfp_alink_xstats xstats;
 };
 
 /**
@@ -85,6 +119,10 @@ struct nfp_abm_link {
 void nfp_abm_ctrl_read_params(struct nfp_abm_link *alink);
 int nfp_abm_ctrl_find_addrs(struct nfp_abm *abm);
 int nfp_abm_ctrl_set_all_q_lvls(struct nfp_abm_link *alink, u32 val);
+int nfp_abm_ctrl_read_stats(struct nfp_abm_link *alink,
+			    struct nfp_alink_stats *stats);
+int nfp_abm_ctrl_read_xstats(struct nfp_abm_link *alink,
+			     struct nfp_alink_xstats *xstats);
 int nfp_abm_ctrl_qm_enable(struct nfp_abm *abm);
 int nfp_abm_ctrl_qm_disable(struct nfp_abm *abm);
 #endif