net: lan966x: Add offload support for tbf

The tbf qdisc allows to attach a shaper on traffic egress on a port or
on a queue. On port they are attached directly to the root and on queue
they are attached on one of the classes of the parent qdisc.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/lan966x/Makefile

@@ -9,4 +9,5 @@ lan966x-switch-objs  := lan966x_main.o lan966x_phylink.o lan966x_port.o \
 			lan966x_mac.o lan966x_ethtool.o lan966x_switchdev.o \
 			lan966x_vlan.o lan966x_fdb.o lan966x_mdb.o \
 			lan966x_ptp.o lan966x_fdma.o lan966x_lag.o \
-			lan966x_tc.o lan966x_mqprio.o lan966x_taprio.o
+			lan966x_tc.o lan966x_mqprio.o lan966x_taprio.o \
+			lan966x_tbf.o

drivers/net/ethernet/microchip/lan966x/lan966x_main.h

@@ -9,6 +9,7 @@
 #include <linux/phy.h>
 #include <linux/phylink.h>
 #include <linux/ptp_clock_kernel.h>
+#include <net/pkt_cls.h>
 #include <net/pkt_sched.h>
 #include <net/switchdev.h>
 
@@ -81,6 +82,9 @@
 #define FDMA_INJ_CHANNEL		0
 #define FDMA_DCB_MAX			512
 
+#define SE_IDX_QUEUE			0  /* 0-79 : Queue scheduler elements */
+#define SE_IDX_PORT			80 /* 80-89 : Port schedular elements */
+
 /* MAC table entry types.
  * ENTRYTYPE_NORMAL is subject to aging.
  * ENTRYTYPE_LOCKED is not subject to aging.
@@ -462,6 +466,11 @@ int lan966x_taprio_add(struct lan966x_port *port,
 int lan966x_taprio_del(struct lan966x_port *port);
 int lan966x_taprio_speed_set(struct lan966x_port *port, int speed);
 
+int lan966x_tbf_add(struct lan966x_port *port,
+		    struct tc_tbf_qopt_offload *qopt);
+int lan966x_tbf_del(struct lan966x_port *port,
+		    struct tc_tbf_qopt_offload *qopt);
+
 static inline void __iomem *lan_addr(void __iomem *base[],
 				     int id, int tinst, int tcnt,
 				     int gbase, int ginst,

drivers/net/ethernet/microchip/lan966x/lan966x_regs.h

@@ -1018,6 +1018,36 @@ enum lan966x_target {
 /*      QSYS:RES_CTRL:RES_CFG */
 #define QSYS_RES_CFG(g)           __REG(TARGET_QSYS, 0, 1, 32768, g, 1024, 8, 0, 0, 1, 4)
 
+/*      QSYS:HSCH:CIR_CFG */
+#define QSYS_CIR_CFG(g)           __REG(TARGET_QSYS, 0, 1, 16384, g, 90, 128, 0, 0, 1, 4)
+
+#define QSYS_CIR_CFG_CIR_RATE                    GENMASK(20, 6)
+#define QSYS_CIR_CFG_CIR_RATE_SET(x)\
+	FIELD_PREP(QSYS_CIR_CFG_CIR_RATE, x)
+#define QSYS_CIR_CFG_CIR_RATE_GET(x)\
+	FIELD_GET(QSYS_CIR_CFG_CIR_RATE, x)
+
+#define QSYS_CIR_CFG_CIR_BURST                   GENMASK(5, 0)
+#define QSYS_CIR_CFG_CIR_BURST_SET(x)\
+	FIELD_PREP(QSYS_CIR_CFG_CIR_BURST, x)
+#define QSYS_CIR_CFG_CIR_BURST_GET(x)\
+	FIELD_GET(QSYS_CIR_CFG_CIR_BURST, x)
+
+/*      QSYS:HSCH:SE_CFG */
+#define QSYS_SE_CFG(g)            __REG(TARGET_QSYS, 0, 1, 16384, g, 90, 128, 8, 0, 1, 4)
+
+#define QSYS_SE_CFG_SE_AVB_ENA                   BIT(4)
+#define QSYS_SE_CFG_SE_AVB_ENA_SET(x)\
+	FIELD_PREP(QSYS_SE_CFG_SE_AVB_ENA, x)
+#define QSYS_SE_CFG_SE_AVB_ENA_GET(x)\
+	FIELD_GET(QSYS_SE_CFG_SE_AVB_ENA, x)
+
+#define QSYS_SE_CFG_SE_FRM_MODE                  GENMASK(3, 2)
+#define QSYS_SE_CFG_SE_FRM_MODE_SET(x)\
+	FIELD_PREP(QSYS_SE_CFG_SE_FRM_MODE, x)
+#define QSYS_SE_CFG_SE_FRM_MODE_GET(x)\
+	FIELD_GET(QSYS_SE_CFG_SE_FRM_MODE, x)
+
 /*      QSYS:TAS_CONFIG:TAS_CFG_CTRL */
 #define QSYS_TAS_CFG_CTRL         __REG(TARGET_QSYS, 0, 1, 57372, 0, 1, 12, 0, 0, 1, 4)
 

drivers/net/ethernet/microchip/lan966x/lan966x_tbf.c

@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include "lan966x_main.h"
+
+int lan966x_tbf_add(struct lan966x_port *port,
+		    struct tc_tbf_qopt_offload *qopt)
+{
+	struct lan966x *lan966x = port->lan966x;
+	bool root = qopt->parent == TC_H_ROOT;
+	u32 queue = 0;
+	u32 cir, cbs;
+	u32 se_idx;
+
+	if (!root) {
+		queue = TC_H_MIN(qopt->parent) - 1;
+		if (queue >= NUM_PRIO_QUEUES)
+			return -EOPNOTSUPP;
+	}
+
+	if (root)
+		se_idx = SE_IDX_PORT + port->chip_port;
+	else
+		se_idx = SE_IDX_QUEUE + port->chip_port * NUM_PRIO_QUEUES + queue;
+
+	cir = div_u64(qopt->replace_params.rate.rate_bytes_ps, 1000) * 8;
+	cbs = qopt->replace_params.max_size;
+
+	/* Rate unit is 100 kbps */
+	cir = DIV_ROUND_UP(cir, 100);
+	/* Avoid using zero rate */
+	cir = cir ?: 1;
+	/* Burst unit is 4kB */
+	cbs = DIV_ROUND_UP(cbs, 4096);
+	/* Avoid using zero burst */
+	cbs = cbs ?: 1;
+
+	/* Check that actually the result can be written */
+	if (cir > GENMASK(15, 0) ||
+	    cbs > GENMASK(6, 0))
+		return -EINVAL;
+
+	lan_rmw(QSYS_SE_CFG_SE_AVB_ENA_SET(0) |
+		QSYS_SE_CFG_SE_FRM_MODE_SET(1),
+		QSYS_SE_CFG_SE_AVB_ENA |
+		QSYS_SE_CFG_SE_FRM_MODE,
+		lan966x, QSYS_SE_CFG(se_idx));
+
+	lan_wr(QSYS_CIR_CFG_CIR_RATE_SET(cir) |
+	       QSYS_CIR_CFG_CIR_BURST_SET(cbs),
+	       lan966x, QSYS_CIR_CFG(se_idx));
+
+	return 0;
+}
+
+int lan966x_tbf_del(struct lan966x_port *port,
+		    struct tc_tbf_qopt_offload *qopt)
+{
+	struct lan966x *lan966x = port->lan966x;
+	bool root = qopt->parent == TC_H_ROOT;
+	u32 queue = 0;
+	u32 se_idx;
+
+	if (!root) {
+		queue = TC_H_MIN(qopt->parent) - 1;
+		if (queue >= NUM_PRIO_QUEUES)
+			return -EOPNOTSUPP;
+	}
+
+	if (root)
+		se_idx = SE_IDX_PORT + port->chip_port;
+	else
+		se_idx = SE_IDX_QUEUE + port->chip_port * NUM_PRIO_QUEUES + queue;
+
+	lan_rmw(QSYS_SE_CFG_SE_AVB_ENA_SET(0) |
+		QSYS_SE_CFG_SE_FRM_MODE_SET(0),
+		QSYS_SE_CFG_SE_AVB_ENA |
+		QSYS_SE_CFG_SE_FRM_MODE,
+		lan966x, QSYS_SE_CFG(se_idx));
+
+	lan_wr(QSYS_CIR_CFG_CIR_RATE_SET(0) |
+	       QSYS_CIR_CFG_CIR_BURST_SET(0),
+	       lan966x, QSYS_CIR_CFG(se_idx));
+
+	return 0;
+}

drivers/net/ethernet/microchip/lan966x/lan966x_tc.c

@@ -22,6 +22,21 @@ static int lan966x_tc_setup_qdisc_taprio(struct lan966x_port *port,
 				lan966x_taprio_del(port);
 }
 
+static int lan966x_tc_setup_qdisc_tbf(struct lan966x_port *port,
+				      struct tc_tbf_qopt_offload *qopt)
+{
+	switch (qopt->command) {
+	case TC_TBF_REPLACE:
+		return lan966x_tbf_add(port, qopt);
+	case TC_TBF_DESTROY:
+		return lan966x_tbf_del(port, qopt);
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return -EOPNOTSUPP;
+}
+
 int lan966x_tc_setup(struct net_device *dev, enum tc_setup_type type,
 		     void *type_data)
 {
@@ -32,6 +47,8 @@ int lan966x_tc_setup(struct net_device *dev, enum tc_setup_type type,
 		return lan966x_tc_setup_qdisc_mqprio(port, type_data);
 	case TC_SETUP_QDISC_TAPRIO:
 		return lan966x_tc_setup_qdisc_taprio(port, type_data);
+	case TC_SETUP_QDISC_TBF:
+		return lan966x_tc_setup_qdisc_tbf(port, type_data);
 	default:
 		return -EOPNOTSUPP;
 	}