net: mvpp2: debugfs: add hit counter stats for Header Parser entries

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@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

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;
 }
 

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;
+}

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