Subject: [PATCH] net: ethernet: mediatek: fix ppe flow accounting for L2 flows
From: Felix Fietkau <[email-masked]>
Date: Thu, 23 Mar 2023 11:05:22 +0100

For L2 flows, the packet/byte counters should report the sum of the
counters of their subflows, both current and expired.
In order to make this work, change the way that accounting data is tracked.
Reset counters when a flow enters bind. Once it expires (or enters unbind),
store the last counter value in struct mtk_flow_entry.

Signed-off-by: Felix Fietkau <[email-masked]>
---

--- a/drivers/net/ethernet/mediatek/mtk_ppe.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.c
@@ -79,9 +79,9 @@ static int mtk_ppe_mib_wait_busy(struct
 	int ret;
 	u32 val;
 
-	ret = readl_poll_timeout(ppe->base + MTK_PPE_MIB_SER_CR, val,
-				 !(val & MTK_PPE_MIB_SER_CR_ST),
-				 20, MTK_PPE_WAIT_TIMEOUT_US);
+	ret = readl_poll_timeout_atomic(ppe->base + MTK_PPE_MIB_SER_CR, val,
+					!(val & MTK_PPE_MIB_SER_CR_ST),
+					20, MTK_PPE_WAIT_TIMEOUT_US);
 
 	if (ret)
 		dev_err(ppe->dev, "MIB table busy");
@@ -89,17 +89,31 @@ static int mtk_ppe_mib_wait_busy(struct
 	return ret;
 }
 
-static int mtk_mib_entry_read(struct mtk_ppe *ppe, u16 index, u64 *bytes, u64 *packets)
+static inline struct mtk_foe_accounting *
+mtk_ppe_acct_data(struct mtk_ppe *ppe, u16 index)
+{
+	if (!ppe->acct_table)
+		return NULL;
+
+	return ppe->acct_table + index * sizeof(struct mtk_foe_accounting);
+}
+
+struct mtk_foe_accounting *mtk_ppe_mib_entry_read(struct mtk_ppe *ppe, u16 index)
 {
 	u32 val, cnt_r0, cnt_r1, cnt_r2;
+	struct mtk_foe_accounting *acct;
 	int ret;
 
 	val = FIELD_PREP(MTK_PPE_MIB_SER_CR_ADDR, index) | MTK_PPE_MIB_SER_CR_ST;
 	ppe_w32(ppe, MTK_PPE_MIB_SER_CR, val);
 
+	acct = mtk_ppe_acct_data(ppe, index);
+	if (!acct)
+		return NULL;
+
 	ret = mtk_ppe_mib_wait_busy(ppe);
 	if (ret)
-		return ret;
+		return acct;
 
 	cnt_r0 = readl(ppe->base + MTK_PPE_MIB_SER_R0);
 	cnt_r1 = readl(ppe->base + MTK_PPE_MIB_SER_R1);
@@ -108,19 +122,19 @@ static int mtk_mib_entry_read(struct mtk
 	if (mtk_is_netsys_v3_or_greater(ppe->eth)) {
 		/* 64 bit for each counter */
 		u32 cnt_r3 = readl(ppe->base + MTK_PPE_MIB_SER_R3);
-		*bytes = ((u64)cnt_r1 << 32) | cnt_r0;
-		*packets = ((u64)cnt_r3 << 32) | cnt_r2;
+		acct->bytes += ((u64)cnt_r1 << 32) | cnt_r0;
+		acct->packets += ((u64)cnt_r3 << 32) | cnt_r2;
 	} else {
 		/* 48 bit byte counter, 40 bit packet counter */
 		u32 byte_cnt_low = FIELD_GET(MTK_PPE_MIB_SER_R0_BYTE_CNT_LOW, cnt_r0);
 		u32 byte_cnt_high = FIELD_GET(MTK_PPE_MIB_SER_R1_BYTE_CNT_HIGH, cnt_r1);
 		u32 pkt_cnt_low = FIELD_GET(MTK_PPE_MIB_SER_R1_PKT_CNT_LOW, cnt_r1);
 		u32 pkt_cnt_high = FIELD_GET(MTK_PPE_MIB_SER_R2_PKT_CNT_HIGH, cnt_r2);
-		*bytes = ((u64)byte_cnt_high << 32) | byte_cnt_low;
-		*packets = (pkt_cnt_high << 16) | pkt_cnt_low;
+		acct->bytes += ((u64)byte_cnt_high << 32) | byte_cnt_low;
+		acct->packets += (pkt_cnt_high << 16) | pkt_cnt_low;
 	}
 
-	return 0;
+	return acct;
 }
 
 static void mtk_ppe_cache_clear(struct mtk_ppe *ppe)
@@ -525,13 +539,6 @@ __mtk_foe_entry_clear(struct mtk_ppe *pp
 		hwe->ib1 |= FIELD_PREP(MTK_FOE_IB1_STATE, MTK_FOE_STATE_INVALID);
 		dma_wmb();
 		mtk_ppe_cache_clear(ppe);
-		if (ppe->accounting) {
-			struct mtk_foe_accounting *acct;
-
-			acct = ppe->acct_table + entry->hash * sizeof(*acct);
-			acct->packets = 0;
-			acct->bytes = 0;
-		}
 	}
 	entry->hash = 0xffff;
 
@@ -556,11 +563,14 @@ static int __mtk_foe_entry_idle_time(str
 }
 
 static bool
-mtk_flow_entry_update(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
+mtk_flow_entry_update(struct mtk_ppe *ppe, struct mtk_flow_entry *entry,
+		      u64 *packets, u64 *bytes)
 {
+	struct mtk_foe_accounting *acct;
 	struct mtk_foe_entry foe = {};
 	struct mtk_foe_entry *hwe;
 	u16 hash = entry->hash;
+	bool ret = false;
 	int len;
 
 	if (hash == 0xffff)
@@ -571,18 +581,35 @@ mtk_flow_entry_update(struct mtk_ppe *pp
 	memcpy(&foe, hwe, len);
 
 	if (!mtk_flow_entry_match(ppe->eth, entry, &foe, len) ||
-	    FIELD_GET(MTK_FOE_IB1_STATE, foe.ib1) != MTK_FOE_STATE_BIND)
-		return false;
+	    FIELD_GET(MTK_FOE_IB1_STATE, foe.ib1) != MTK_FOE_STATE_BIND) {
+		acct = mtk_ppe_acct_data(ppe, hash);
+		if (acct) {
+			entry->prev_packets += acct->packets;
+			entry->prev_bytes += acct->bytes;
+		}
+
+		goto out;
+	}
 
 	entry->data.ib1 = foe.ib1;
+	acct = mtk_ppe_mib_entry_read(ppe, hash);
+	ret = true;
+
+out:
+	if (acct) {
+		*packets += acct->packets;
+		*bytes += acct->bytes;
+	}
 
-	return true;
+	return ret;
 }
 
 static void
 mtk_flow_entry_update_l2(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
 {
 	u32 ib1_ts_mask = mtk_get_ib1_ts_mask(ppe->eth);
+	u64 *packets = &entry->packets;
+	u64 *bytes = &entry->bytes;
 	struct mtk_flow_entry *cur;
 	struct hlist_node *tmp;
 	int idle;
@@ -591,7 +618,9 @@ mtk_flow_entry_update_l2(struct mtk_ppe
 	hlist_for_each_entry_safe(cur, tmp, &entry->l2_flows, l2_list) {
 		int cur_idle;
 
-		if (!mtk_flow_entry_update(ppe, cur)) {
+		if (!mtk_flow_entry_update(ppe, cur, packets, bytes)) {
+			entry->prev_packets += cur->prev_packets;
+			entry->prev_bytes += cur->prev_bytes;
 			__mtk_foe_entry_clear(ppe, entry, false);
 			continue;
 		}
@@ -606,10 +635,29 @@ mtk_flow_entry_update_l2(struct mtk_ppe
 	}
 }
 
+void mtk_foe_entry_get_stats(struct mtk_ppe *ppe, struct mtk_flow_entry *entry,
+			     int *idle)
+{
+	entry->packets = entry->prev_packets;
+	entry->bytes = entry->prev_bytes;
+
+	spin_lock_bh(&ppe_lock);
+
+	if (entry->type == MTK_FLOW_TYPE_L2)
+		mtk_flow_entry_update_l2(ppe, entry);
+	else
+		mtk_flow_entry_update(ppe, entry, &entry->packets, &entry->bytes);
+
+	*idle = __mtk_foe_entry_idle_time(ppe, entry->data.ib1);
+
+	spin_unlock_bh(&ppe_lock);
+}
+
 static void
 __mtk_foe_entry_commit(struct mtk_ppe *ppe, struct mtk_foe_entry *entry,
 		       u16 hash)
 {
+	struct mtk_foe_accounting *acct;
 	struct mtk_eth *eth = ppe->eth;
 	u16 timestamp = mtk_eth_timestamp(eth);
 	struct mtk_foe_entry *hwe;
@@ -640,6 +688,12 @@ __mtk_foe_entry_commit(struct mtk_ppe *p
 
 	dma_wmb();
 
+	acct = mtk_ppe_mib_entry_read(ppe, hash);
+	if (acct) {
+		acct->packets = 0;
+		acct->bytes = 0;
+	}
+
 	mtk_ppe_cache_clear(ppe);
 }
 
@@ -802,21 +856,6 @@ out:
 	spin_unlock_bh(&ppe_lock);
 }
 
-int mtk_foe_entry_idle_time(struct mtk_ppe *ppe, struct mtk_flow_entry *entry)
-{
-	int idle;
-
-	spin_lock_bh(&ppe_lock);
-	if (entry->type == MTK_FLOW_TYPE_L2)
-		mtk_flow_entry_update_l2(ppe, entry);
-	else
-		mtk_flow_entry_update(ppe, entry);
-	idle = __mtk_foe_entry_idle_time(ppe, entry->data.ib1);
-	spin_unlock_bh(&ppe_lock);
-
-	return idle;
-}
-
 int mtk_ppe_prepare_reset(struct mtk_ppe *ppe)
 {
 	if (!ppe)
@@ -844,32 +883,6 @@ int mtk_ppe_prepare_reset(struct mtk_ppe
 	return mtk_ppe_wait_busy(ppe);
 }
 
-struct mtk_foe_accounting *mtk_foe_entry_get_mib(struct mtk_ppe *ppe, u32 index,
-						 struct mtk_foe_accounting *diff)
-{
-	struct mtk_foe_accounting *acct;
-	int size = sizeof(struct mtk_foe_accounting);
-	u64 bytes, packets;
-
-	if (!ppe->accounting)
-		return NULL;
-
-	if (mtk_mib_entry_read(ppe, index, &bytes, &packets))
-		return NULL;
-
-	acct = ppe->acct_table + index * size;
-
-	acct->bytes += bytes;
-	acct->packets += packets;
-
-	if (diff) {
-		diff->bytes = bytes;
-		diff->packets = packets;
-	}
-
-	return acct;
-}
-
 struct mtk_ppe *mtk_ppe_init(struct mtk_eth *eth, void __iomem *base, int index)
 {
 	bool accounting = eth->soc->has_accounting;
--- a/drivers/net/ethernet/mediatek/mtk_ppe.h
+++ b/drivers/net/ethernet/mediatek/mtk_ppe.h
@@ -304,6 +304,8 @@ struct mtk_flow_entry {
 	struct mtk_foe_entry data;
 	struct rhash_head node;
 	unsigned long cookie;
+	u64 prev_packets, prev_bytes;
+	u64 packets, bytes;
 };
 
 struct mtk_mib_entry {
@@ -347,6 +349,7 @@ void mtk_ppe_deinit(struct mtk_eth *eth)
 void mtk_ppe_start(struct mtk_ppe *ppe);
 int mtk_ppe_stop(struct mtk_ppe *ppe);
 int mtk_ppe_prepare_reset(struct mtk_ppe *ppe);
+struct mtk_foe_accounting *mtk_ppe_mib_entry_read(struct mtk_ppe *ppe, u16 index);
 
 void __mtk_ppe_check_skb(struct mtk_ppe *ppe, struct sk_buff *skb, u16 hash);
 
@@ -395,9 +398,8 @@ int mtk_foe_entry_set_queue(struct mtk_e
 			    unsigned int queue);
 int mtk_foe_entry_commit(struct mtk_ppe *ppe, struct mtk_flow_entry *entry);
 void mtk_foe_entry_clear(struct mtk_ppe *ppe, struct mtk_flow_entry *entry);
-int mtk_foe_entry_idle_time(struct mtk_ppe *ppe, struct mtk_flow_entry *entry);
 int mtk_ppe_debugfs_init(struct mtk_ppe *ppe, int index);
-struct mtk_foe_accounting *mtk_foe_entry_get_mib(struct mtk_ppe *ppe, u32 index,
-						 struct mtk_foe_accounting *diff);
+void mtk_foe_entry_get_stats(struct mtk_ppe *ppe, struct mtk_flow_entry *entry,
+			     int *idle);
 
 #endif
--- a/drivers/net/ethernet/mediatek/mtk_ppe_debugfs.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe_debugfs.c
@@ -96,7 +96,7 @@ mtk_ppe_debugfs_foe_show(struct seq_file
 		if (bind && state != MTK_FOE_STATE_BIND)
 			continue;
 
-		acct = mtk_foe_entry_get_mib(ppe, i, NULL);
+		acct = mtk_ppe_mib_entry_read(ppe, i);
 
 		type = mtk_get_ib1_pkt_type(ppe->eth, entry->ib1);
 		seq_printf(m, "%05x %s %7s", i,
--- a/drivers/net/ethernet/mediatek/mtk_ppe_offload.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe_offload.c
@@ -499,24 +499,21 @@ static int
 mtk_flow_offload_stats(struct mtk_eth *eth, struct flow_cls_offload *f)
 {
 	struct mtk_flow_entry *entry;
-	struct mtk_foe_accounting diff;
-	u32 idle;
+	u64 packets, bytes;
+	int idle;
 
 	entry = rhashtable_lookup(&eth->flow_table, &f->cookie,
 				  mtk_flow_ht_params);
 	if (!entry)
 		return -ENOENT;
 
-	idle = mtk_foe_entry_idle_time(eth->ppe[entry->ppe_index], entry);
+	packets = entry->packets;
+	bytes = entry->bytes;
+	mtk_foe_entry_get_stats(eth->ppe[entry->ppe_index], entry, &idle);
+	f->stats.pkts += entry->packets - packets;
+	f->stats.bytes += entry->bytes - bytes;
 	f->stats.lastused = jiffies - idle * HZ;
 
-	if (entry->hash != 0xFFFF &&
-	    mtk_foe_entry_get_mib(eth->ppe[entry->ppe_index], entry->hash,
-				  &diff)) {
-		f->stats.pkts += diff.packets;
-		f->stats.bytes += diff.bytes;
-	}
-
 	return 0;
 }