[PATCH net-next v2 3/5] net: mvpp2: debugfs: add hit counter stats for Header Parser entries

[Maxime Chevallier]

One helpful feature to help debug the Header Parser TCAM filter in PPv2
is to be able to see if the entries did match something when a packet
comes in. This can be done by using the built-in hit counter for TCAM
entries.

This commit implements reading the counter, and exposing its value on
debugfs for each filter entry.

The counter is a 16-bits clear-on-read value, located at:
 .../mvpp2/<controller>/parser/XXX/hits

Signed-off-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2.h         |  3 +++
 drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c | 19 +++++++++++++++++++
 drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.c     | 16 ++++++++++++++++
 drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.h     |  2 ++
 4 files changed, 40 insertions(+)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
index 439f14192b08..70b3e9cd0d84 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h
@@ -64,6 +64,9 @@
 #define MVPP2_PRS_SRAM_DATA_REG(idx)		(0x1204 + (idx) * 4)
 #define MVPP2_PRS_TCAM_CTRL_REG			0x1230
 #define     MVPP2_PRS_TCAM_EN_MASK		BIT(0)
+#define MVPP2_PRS_TCAM_HIT_IDX_REG		0x1240
+#define MVPP2_PRS_TCAM_HIT_CNT_REG		0x1244
+#define     MVPP2_PRS_TCAM_HIT_CNT_MASK		GENMASK(15, 0)
 
 /* RSS Registers */
 #define MVPP22_RSS_INDEX			0x1500
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c
index e8a242b56519..af8fb93a8ae2 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_debugfs.c
@@ -192,6 +192,22 @@ static int mvpp2_dbgfs_prs_sram_show(struct seq_file *s, void *unused)
 
 DEFINE_SHOW_ATTRIBUTE(mvpp2_dbgfs_prs_sram);
 
+static int mvpp2_dbgfs_prs_hits_show(struct seq_file *s, void *unused)
+{
+	struct mvpp2_dbgfs_prs_entry *entry = s->private;
+	int val;
+
+	val = mvpp2_prs_hits(entry->priv, entry->tid);
+	if (val < 0)
+		return val;
+
+	seq_printf(s, "%d\n", val);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(mvpp2_dbgfs_prs_hits);
+
 static int mvpp2_dbgfs_prs_valid_show(struct seq_file *s, void *unused)
 {
 	struct mvpp2_dbgfs_prs_entry *entry = s->private;
@@ -263,6 +279,9 @@ static int mvpp2_dbgfs_prs_entry_init(struct dentry *parent,
 	debugfs_create_file("header_data", 0644, prs_entry_dir, entry,
 			    &mvpp2_dbgfs_prs_hdata_fops);
 
+	debugfs_create_file("hits", 0444, prs_entry_dir, entry,
+			    &mvpp2_dbgfs_prs_hits_fops);
+
 	return 0;
 }
 
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.c
index f133d820f0fa..392fd895f278 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.c
@@ -2478,3 +2478,19 @@ int mvpp2_prs_def_flow(struct mvpp2_port *port)
 
 	return 0;
 }
+
+int mvpp2_prs_hits(struct mvpp2 *priv, int index)
+{
+	u32 val;
+
+	if (index > MVPP2_PRS_TCAM_SRAM_SIZE)
+		return -EINVAL;
+
+	mvpp2_write(priv, MVPP2_PRS_TCAM_HIT_IDX_REG, index);
+
+	val = mvpp2_read(priv, MVPP2_PRS_TCAM_HIT_CNT_REG);
+
+	val &= MVPP2_PRS_TCAM_HIT_CNT_MASK;
+
+	return val;
+}
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.h b/drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.h
index 67b67ccb387d..e22f6c85d380 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.h
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.h
@@ -328,4 +328,6 @@ void mvpp2_prs_mac_del_all(struct mvpp2_port *port);
 
 int mvpp2_prs_update_mac_da(struct net_device *dev, const u8 *da);
 
+int mvpp2_prs_hits(struct mvpp2 *priv, int index);
+
 #endif
-- 
2.11.0