[PATCH net-next v3 2/2] net: mana: Add standard counter rx_missed_errors

[Erni Sri Satya Vennela <ernis@linux.microsoft.com>]

Report standard counter stats->rx_missed_errors
using hc_rx_discards_no_wqe from the hardware.

Add a global workqueue to periodically run
mana_query_gf_stats every 2 seconds to get the latest
info in eth_stats and define a driver capability flag
to notify hardware of the periodic queries.

To avoid repeated failures and log flooding, the workqueue
is not rescheduled if mana_query_gf_stats fails on HWC timeout
error and the stats are reset to 0. Other errors are transient
which will not need a VF reset for recovery.

Signed-off-by: Erni Sri Satya Vennela <ernis@linux.microsoft.com>
---
Changes in v3:
* Use schedule_delayed_work (global workqueue) instead of
  queue_delayed_work (dedicated workqueue) in MANA driver.
* Update commit message.
Changes in v2:
* Update commit message.
* Stop rescheduling workqueue only when HWC timeout is observed.
* Introduce new variable in mana_context for detecting HWC timeout.
* Warn once in mana_get_stat64 when HWC timeout is observed.
---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 36 +++++++++++++++++--
 .../ethernet/microsoft/mana/mana_ethtool.c    |  2 --
 include/net/mana/gdma.h                       |  6 +++-
 include/net/mana/mana.h                       |  6 +++-
 4 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index d8ce4402c696..13f47be7aca6 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -534,6 +534,11 @@ static void mana_get_stats64(struct net_device *ndev,
 
 	netdev_stats_to_stats64(st, &ndev->stats);
 
+	if (apc->ac->hwc_timeout_occurred)
+		netdev_warn_once(ndev, "HWC timeout occurred\n");
+
+	st->rx_missed_errors = apc->ac->hc_stats.hc_rx_discards_no_wqe;
+
 	for (q = 0; q < num_queues; q++) {
 		rx_stats = &apc->rxqs[q]->stats;
 
@@ -2809,7 +2814,7 @@ int mana_config_rss(struct mana_port_context *apc, enum TRI_STATE rx,
 	return 0;
 }
 
-void mana_query_gf_stats(struct mana_context *ac)
+int mana_query_gf_stats(struct mana_context *ac)
 {
 	struct gdma_context *gc = ac->gdma_dev->gdma_context;
 	struct mana_query_gf_stat_resp resp = {};
@@ -2852,14 +2857,14 @@ void mana_query_gf_stats(struct mana_context *ac)
 				sizeof(resp));
 	if (err) {
 		dev_err(dev, "Failed to query GF stats: %d\n", err);
-		return;
+		return err;
 	}
 	err = mana_verify_resp_hdr(&resp.hdr, MANA_QUERY_GF_STAT,
 				   sizeof(resp));
 	if (err || resp.hdr.status) {
 		dev_err(dev, "Failed to query GF stats: %d, 0x%x\n", err,
 			resp.hdr.status);
-		return;
+		return err;
 	}
 
 	ac->hc_stats.hc_rx_discards_no_wqe = resp.rx_discards_nowqe;
@@ -2894,6 +2899,8 @@ void mana_query_gf_stats(struct mana_context *ac)
 	ac->hc_stats.hc_tx_mcast_pkts = resp.hc_tx_mcast_pkts;
 	ac->hc_stats.hc_tx_mcast_bytes = resp.hc_tx_mcast_bytes;
 	ac->hc_stats.hc_tx_err_gdma = resp.tx_err_gdma;
+
+	return 0;
 }
 
 void mana_query_phy_stats(struct mana_port_context *apc)
@@ -3428,6 +3435,24 @@ int mana_rdma_service_event(struct gdma_context *gc, enum gdma_service_type even
 	return 0;
 }
 
+#define MANA_GF_STATS_PERIOD (2 * HZ)
+
+static void mana_gf_stats_work_handler(struct work_struct *work)
+{
+	struct mana_context *ac =
+		container_of(to_delayed_work(work), struct mana_context, gf_stats_work);
+	int err;
+
+	err = mana_query_gf_stats(ac);
+	if (err == -ETIMEDOUT) {
+		/* HWC timeout detected - reset stats and stop rescheduling */
+		ac->hwc_timeout_occurred = true;
+		memset(&ac->hc_stats, 0, sizeof(ac->hc_stats));
+		return;
+	}
+	schedule_delayed_work(&ac->gf_stats_work, MANA_GF_STATS_PERIOD);
+}
+
 int mana_probe(struct gdma_dev *gd, bool resuming)
 {
 	struct gdma_context *gc = gd->gdma_context;
@@ -3520,6 +3545,10 @@ int mana_probe(struct gdma_dev *gd, bool resuming)
 	}
 
 	err = add_adev(gd, "eth");
+
+	INIT_DELAYED_WORK(&ac->gf_stats_work, mana_gf_stats_work_handler);
+	schedule_delayed_work(&ac->gf_stats_work, MANA_GF_STATS_PERIOD);
+
 out:
 	if (err) {
 		mana_remove(gd, false);
@@ -3544,6 +3573,7 @@ void mana_remove(struct gdma_dev *gd, bool suspending)
 	int i;
 
 	disable_work_sync(&ac->link_change_work);
+	cancel_delayed_work_sync(&ac->gf_stats_work);
 
 	/* adev currently doesn't support suspending, always remove it */
 	if (gd->adev)
diff --git a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
index 3dfd96146424..99e811208683 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c
@@ -213,8 +213,6 @@ static void mana_get_ethtool_stats(struct net_device *ndev,
 
 	if (!apc->port_is_up)
 		return;
-	/* we call mana function to update stats from GDMA */
-	mana_query_gf_stats(apc->ac);
 
 	/* We call this mana function to get the phy stats from GDMA and includes
 	 * aggregate tx/rx drop counters, Per-TC(Traffic Channel) tx/rx and pause
diff --git a/include/net/mana/gdma.h b/include/net/mana/gdma.h
index 637f42485dba..2e4f2f3175e5 100644
--- a/include/net/mana/gdma.h
+++ b/include/net/mana/gdma.h
@@ -592,6 +592,9 @@ enum {
 #define GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE BIT(17)
 #define GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE BIT(6)
 
+/* Driver can send HWC periodically to query stats */
+#define GDMA_DRV_CAP_FLAG_1_PERIODIC_STATS_QUERY BIT(21)
+
 #define GDMA_DRV_CAP_FLAGS1 \
 	(GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT | \
 	 GDMA_DRV_CAP_FLAG_1_NAPI_WKDONE_FIX | \
@@ -601,7 +604,8 @@ enum {
 	 GDMA_DRV_CAP_FLAG_1_DYNAMIC_IRQ_ALLOC_SUPPORT | \
 	 GDMA_DRV_CAP_FLAG_1_SELF_RESET_ON_EQE | \
 	 GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE | \
-	 GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE)
+	 GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE | \
+	 GDMA_DRV_CAP_FLAG_1_PERIODIC_STATS_QUERY)
 
 #define GDMA_DRV_CAP_FLAGS2 0
 
diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
index 3484f42803e3..d37f4cea0ac3 100644
--- a/include/net/mana/mana.h
+++ b/include/net/mana/mana.h
@@ -480,6 +480,10 @@ struct mana_context {
 	struct mana_eq *eqs;
 	struct dentry *mana_eqs_debugfs;
 
+	/* Workqueue for querying hardware stats */
+	struct delayed_work gf_stats_work;
+	bool hwc_timeout_occurred;
+
 	struct net_device *ports[MAX_PORTS_IN_MANA_DEV];
 
 	/* Link state change work */
@@ -581,7 +585,7 @@ u32 mana_run_xdp(struct net_device *ndev, struct mana_rxq *rxq,
 struct bpf_prog *mana_xdp_get(struct mana_port_context *apc);
 void mana_chn_setxdp(struct mana_port_context *apc, struct bpf_prog *prog);
 int mana_bpf(struct net_device *ndev, struct netdev_bpf *bpf);
-void mana_query_gf_stats(struct mana_context *ac);
+int mana_query_gf_stats(struct mana_context *ac);
 int mana_query_link_cfg(struct mana_port_context *apc);
 int mana_set_bw_clamp(struct mana_port_context *apc, u32 speed,
 		      int enable_clamping);
-- 
2.34.1