[PATCH net-next] net: dsa: mt7530: Add TBF qdisc offload support

[Lorenzo Bianconi]

Introduce port_setup_tc callback in mt7530 dsa driver in order to enable
dsa ports rate shaping via hw Token Bucket Filter (TBF) for hw switched
traffic. Enable hw TBF just for EN7581 SoC for the moment.

Signed-off-by: Lorenzo Bianconi <lorenzo at kernel.org>
---
 drivers/net/dsa/mt7530.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/net/dsa/mt7530.h | 12 +++++++++++
 2 files changed, 66 insertions(+)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index d84ee1b419a614dda5f440e6571cff5f4f27bf21..0adf69ac8827cd66cdc44f9bc43d27ab8acb785c 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -21,6 +21,7 @@
 #include <linux/gpio/consumer.h>
 #include <linux/gpio/driver.h>
 #include <net/dsa.h>
+#include <net/pkt_cls.h>
 
 #include "mt7530.h"
 
@@ -3146,6 +3147,58 @@ mt753x_conduit_state_change(struct dsa_switch *ds,
 	mt7530_rmw(priv, MT753X_MFC, MT7530_CPU_EN | MT7530_CPU_PORT_MASK, val);
 }
 
+static int mt753x_tc_setup_qdisc_tbf(struct mt7530_priv *priv, int port,
+				     struct tc_tbf_qopt_offload *qopt)
+{
+	struct tc_tbf_qopt_offload_replace_params *p = &qopt->replace_params;
+	u32 rate = 0;
+
+	switch (qopt->command) {
+	case TC_TBF_REPLACE:
+		rate = div_u64(p->rate.rate_bytes_ps, 1000) << 3; /* kbps */
+		fallthrough;
+	case TC_TBF_DESTROY: {
+		u32 val, tick;
+
+		mt7530_rmw(priv, MT7530_GERLCR, EGR_BC_MASK,
+			   EGR_BC_CRC_IPG_PREAMBLE);
+
+		/* if rate is greater than 10Mbps tick is 1/32 ms,
+		 * 1ms otherwise
+		 */
+		tick = rate > 10000 ? 2 : 7;
+		val = FIELD_PREP(ERLCR_CIR_MASK, (rate >> 5)) |
+		      FIELD_PREP(ERLCR_EXP_MASK, tick) |
+		      ERLCR_TBF_MODE_MASK |
+		      FIELD_PREP(ERLCR_MANT_MASK, 0xf);
+		if (rate)
+			val |= ERLCR_EN_MASK;
+		mt7530_write(priv, MT7530_ERLCR_P(port), val);
+		break;
+	}
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int mt753x_setup_tc(struct dsa_switch *ds, int port,
+			   enum tc_setup_type type, void *type_data)
+{
+	struct mt7530_priv *priv = ds->priv;
+
+	if (priv->id != ID_EN7581)
+		return -EOPNOTSUPP;
+
+	switch (type) {
+	case TC_SETUP_QDISC_TBF:
+		return mt753x_tc_setup_qdisc_tbf(priv, port, type_data);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
 static int mt7988_setup(struct dsa_switch *ds)
 {
 	struct mt7530_priv *priv = ds->priv;
@@ -3193,6 +3246,7 @@ const struct dsa_switch_ops mt7530_switch_ops = {
 	.get_mac_eee		= mt753x_get_mac_eee,
 	.set_mac_eee		= mt753x_set_mac_eee,
 	.conduit_state_change	= mt753x_conduit_state_change,
+	.port_setup_tc		= mt753x_setup_tc,
 };
 EXPORT_SYMBOL_GPL(mt7530_switch_ops);
 
diff --git a/drivers/net/dsa/mt7530.h b/drivers/net/dsa/mt7530.h
index 6ad33a9f6b1dff3a423baa668a8a2ca158f72b91..9467f2a3f2bca45b3fce3bace2b3b3205158c4bd 100644
--- a/drivers/net/dsa/mt7530.h
+++ b/drivers/net/dsa/mt7530.h
@@ -248,6 +248,18 @@ enum mt7530_vlan_egress_attr {
 #define  AGE_UNIT_MAX			0xfff
 #define  AGE_UNIT(x)			(AGE_UNIT_MASK & (x))
 
+#define MT7530_ERLCR_P(x)		(0x1040 + ((x) * 0x100))
+#define  ERLCR_CIR_MASK			GENMASK(31, 16)
+#define  ERLCR_EN_MASK			BIT(15)
+#define  ERLCR_EXP_MASK			GENMASK(11, 8)
+#define  ERLCR_TBF_MODE_MASK		BIT(7)
+#define  ERLCR_MANT_MASK		GENMASK(6, 0)
+
+#define MT7530_GERLCR			0x10e0
+#define  EGR_BC_MASK			GENMASK(7, 0)
+#define  EGR_BC_CRC			0x4	/* crc */
+#define  EGR_BC_CRC_IPG_PREAMBLE	0x18	/* crc + ipg + preamble */
+
 /* Register for port STP state control */
 #define MT7530_SSP_P(x)			(0x2000 + ((x) * 0x100))
 #define  FID_PST(fid, state)		(((state) & 0x3) << ((fid) * 2))

---
base-commit: 668d663989c77fcb2a92748645e4c394b03d5988
change-id: 20241030-mt7530-tc-offload-05e204441500

Best regards,
-- 
Lorenzo Bianconi <lorenzo at kernel.org>