mellanox/mlxsw/spectrum_qdisc.c

// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/* Copyright (c) 2017-2018 Mellanox Technologies. All rights reserved */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <net/pkt_cls.h>
#include <net/red.h>

#include "spectrum.h"
#include "reg.h"

#define MLXSW_SP_PRIO_BAND_TO_TCLASS(band) (IEEE_8021QAZ_MAX_TCS - band - 1)
#define MLXSW_SP_PRIO_CHILD_TO_TCLASS(child) \
	MLXSW_SP_PRIO_BAND_TO_TCLASS((child - 1))

enum mlxsw_sp_qdisc_type {
	MLXSW_SP_QDISC_NO_QDISC,
	MLXSW_SP_QDISC_RED,
	MLXSW_SP_QDISC_PRIO,
	MLXSW_SP_QDISC_ETS,
	MLXSW_SP_QDISC_TBF,
	MLXSW_SP_QDISC_FIFO,
};

struct mlxsw_sp_qdisc;

struct mlxsw_sp_qdisc_ops {
	enum mlxsw_sp_qdisc_type type;
	int (*check_params)(struct mlxsw_sp_port *mlxsw_sp_port,
			    struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			    void *params);
	int (*replace)(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
		       struct mlxsw_sp_qdisc *mlxsw_sp_qdisc, void *params);
	int (*destroy)(struct mlxsw_sp_port *mlxsw_sp_port,
		       struct mlxsw_sp_qdisc *mlxsw_sp_qdisc);
	int (*get_stats)(struct mlxsw_sp_port *mlxsw_sp_port,
			 struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			 struct tc_qopt_offload_stats *stats_ptr);
	int (*get_xstats)(struct mlxsw_sp_port *mlxsw_sp_port,
			  struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			  void *xstats_ptr);
	void (*clean_stats)(struct mlxsw_sp_port *mlxsw_sp_port,
			    struct mlxsw_sp_qdisc *mlxsw_sp_qdisc);
	/* unoffload - to be used for a qdisc that stops being offloaded without
	 * being destroyed.
	 */
	void (*unoffload)(struct mlxsw_sp_port *mlxsw_sp_port,
			  struct mlxsw_sp_qdisc *mlxsw_sp_qdisc, void *params);
};

struct mlxsw_sp_qdisc {
	u32 handle;
	u8 tclass_num;
	u8 prio_bitmap;
	union {
		struct red_stats red;
	} xstats_base;
	struct mlxsw_sp_qdisc_stats {
		u64 tx_bytes;
		u64 tx_packets;
		u64 drops;
		u64 overlimits;
		u64 backlog;
	} stats_base;

	struct mlxsw_sp_qdisc_ops *ops;
};

struct mlxsw_sp_qdisc_state {
	struct mlxsw_sp_qdisc root_qdisc;
	struct mlxsw_sp_qdisc tclass_qdiscs[IEEE_8021QAZ_MAX_TCS];

	/* When a PRIO or ETS are added, the invisible FIFOs in their bands are
	 * created first. When notifications for these FIFOs arrive, it is not
	 * known what qdisc their parent handle refers to. It could be a
	 * newly-created PRIO that will replace the currently-offloaded one, or
	 * it could be e.g. a RED that will be attached below it.
	 *
	 * As the notifications start to arrive, use them to note what the
	 * future parent handle is, and keep track of which child FIFOs were
	 * seen. Then when the parent is known, retroactively offload those
	 * FIFOs.
	 */
	u32 future_handle;
	bool future_fifos[IEEE_8021QAZ_MAX_TCS];
};

static bool
mlxsw_sp_qdisc_compare(struct mlxsw_sp_qdisc *mlxsw_sp_qdisc, u32 handle,
		       enum mlxsw_sp_qdisc_type type)
{
	return mlxsw_sp_qdisc && mlxsw_sp_qdisc->ops &&
	       mlxsw_sp_qdisc->ops->type == type &&
	       mlxsw_sp_qdisc->handle == handle;
}

static struct mlxsw_sp_qdisc *
mlxsw_sp_qdisc_find(struct mlxsw_sp_port *mlxsw_sp_port, u32 parent,
		    bool root_only)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	int tclass, child_index;

	if (parent == TC_H_ROOT)
		return &qdisc_state->root_qdisc;

	if (root_only || !qdisc_state ||
	    !qdisc_state->root_qdisc.ops ||
	    TC_H_MAJ(parent) != qdisc_state->root_qdisc.handle ||
	    TC_H_MIN(parent) > IEEE_8021QAZ_MAX_TCS)
		return NULL;

	child_index = TC_H_MIN(parent);
	tclass = MLXSW_SP_PRIO_CHILD_TO_TCLASS(child_index);
	return &qdisc_state->tclass_qdiscs[tclass];
}

static struct mlxsw_sp_qdisc *
mlxsw_sp_qdisc_find_by_handle(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	int i;

	if (qdisc_state->root_qdisc.handle == handle)
		return &qdisc_state->root_qdisc;

	if (qdisc_state->root_qdisc.handle == TC_H_UNSPEC)
		return NULL;

	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++)
		if (qdisc_state->tclass_qdiscs[i].handle == handle)
			return &qdisc_state->tclass_qdiscs[i];

	return NULL;
}

static int
mlxsw_sp_qdisc_destroy(struct mlxsw_sp_port *mlxsw_sp_port,
		       struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	int err = 0;

	if (!mlxsw_sp_qdisc)
		return 0;

	if (mlxsw_sp_qdisc->ops && mlxsw_sp_qdisc->ops->destroy)
		err = mlxsw_sp_qdisc->ops->destroy(mlxsw_sp_port,
						   mlxsw_sp_qdisc);

	mlxsw_sp_qdisc->handle = TC_H_UNSPEC;
	mlxsw_sp_qdisc->ops = NULL;
	return err;
}

static int
mlxsw_sp_qdisc_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
		       struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
		       struct mlxsw_sp_qdisc_ops *ops, void *params)
{
	int err;

	if (mlxsw_sp_qdisc->ops && mlxsw_sp_qdisc->ops->type != ops->type)
		/* In case this location contained a different qdisc of the
		 * same type we can override the old qdisc configuration.
		 * Otherwise, we need to remove the old qdisc before setting the
		 * new one.
		 */
		mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
	err = ops->check_params(mlxsw_sp_port, mlxsw_sp_qdisc, params);
	if (err)
		goto err_bad_param;

	err = ops->replace(mlxsw_sp_port, handle, mlxsw_sp_qdisc, params);
	if (err)
		goto err_config;

	/* Check if the Qdisc changed. That includes a situation where an
	 * invisible Qdisc replaces another one, or is being added for the
	 * first time.
	 */
	if (mlxsw_sp_qdisc->handle != handle || handle == TC_H_UNSPEC) {
		mlxsw_sp_qdisc->ops = ops;
		if (ops->clean_stats)
			ops->clean_stats(mlxsw_sp_port, mlxsw_sp_qdisc);
	}

	mlxsw_sp_qdisc->handle = handle;
	return 0;

err_bad_param:
err_config:
	if (mlxsw_sp_qdisc->handle == handle && ops->unoffload)
		ops->unoffload(mlxsw_sp_port, mlxsw_sp_qdisc, params);

	mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
	return err;
}

static int
mlxsw_sp_qdisc_get_stats(struct mlxsw_sp_port *mlxsw_sp_port,
			 struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			 struct tc_qopt_offload_stats *stats_ptr)
{
	if (mlxsw_sp_qdisc && mlxsw_sp_qdisc->ops &&
	    mlxsw_sp_qdisc->ops->get_stats)
		return mlxsw_sp_qdisc->ops->get_stats(mlxsw_sp_port,
						      mlxsw_sp_qdisc,
						      stats_ptr);

	return -EOPNOTSUPP;
}

static int
mlxsw_sp_qdisc_get_xstats(struct mlxsw_sp_port *mlxsw_sp_port,
			  struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			  void *xstats_ptr)
{
	if (mlxsw_sp_qdisc && mlxsw_sp_qdisc->ops &&
	    mlxsw_sp_qdisc->ops->get_xstats)
		return mlxsw_sp_qdisc->ops->get_xstats(mlxsw_sp_port,
						      mlxsw_sp_qdisc,
						      xstats_ptr);

	return -EOPNOTSUPP;
}

static u64
mlxsw_sp_xstats_backlog(struct mlxsw_sp_port_xstats *xstats, int tclass_num)
{
	return xstats->backlog[tclass_num] +
	       xstats->backlog[tclass_num + 8];
}

static u64
mlxsw_sp_xstats_tail_drop(struct mlxsw_sp_port_xstats *xstats, int tclass_num)
{
	return xstats->tail_drop[tclass_num] +
	       xstats->tail_drop[tclass_num + 8];
}

static void
mlxsw_sp_qdisc_bstats_per_priority_get(struct mlxsw_sp_port_xstats *xstats,
				       u8 prio_bitmap, u64 *tx_packets,
				       u64 *tx_bytes)
{
	int i;

	*tx_packets = 0;
	*tx_bytes = 0;
	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
		if (prio_bitmap & BIT(i)) {
			*tx_packets += xstats->tx_packets[i];
			*tx_bytes += xstats->tx_bytes[i];
		}
	}
}

static void
mlxsw_sp_qdisc_collect_tc_stats(struct mlxsw_sp_port *mlxsw_sp_port,
				struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
				u64 *p_tx_bytes, u64 *p_tx_packets,
				u64 *p_drops, u64 *p_backlog)
{
	u8 tclass_num = mlxsw_sp_qdisc->tclass_num;
	struct mlxsw_sp_port_xstats *xstats;
	u64 tx_bytes, tx_packets;

	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;
	mlxsw_sp_qdisc_bstats_per_priority_get(xstats,
					       mlxsw_sp_qdisc->prio_bitmap,
					       &tx_packets, &tx_bytes);

	*p_tx_packets += tx_packets;
	*p_tx_bytes += tx_bytes;
	*p_drops += xstats->wred_drop[tclass_num] +
		    mlxsw_sp_xstats_tail_drop(xstats, tclass_num);
	*p_backlog += mlxsw_sp_xstats_backlog(xstats, tclass_num);
}

static void
mlxsw_sp_qdisc_update_stats(struct mlxsw_sp *mlxsw_sp,
			    struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			    u64 tx_bytes, u64 tx_packets,
			    u64 drops, u64 backlog,
			    struct tc_qopt_offload_stats *stats_ptr)
{
	struct mlxsw_sp_qdisc_stats *stats_base = &mlxsw_sp_qdisc->stats_base;

	tx_bytes -= stats_base->tx_bytes;
	tx_packets -= stats_base->tx_packets;
	drops -= stats_base->drops;
	backlog -= stats_base->backlog;

	_bstats_update(stats_ptr->bstats, tx_bytes, tx_packets);
	stats_ptr->qstats->drops += drops;
	stats_ptr->qstats->backlog += mlxsw_sp_cells_bytes(mlxsw_sp, backlog);

	stats_base->backlog += backlog;
	stats_base->drops += drops;
	stats_base->tx_bytes += tx_bytes;
	stats_base->tx_packets += tx_packets;
}

static void
mlxsw_sp_qdisc_get_tc_stats(struct mlxsw_sp_port *mlxsw_sp_port,
			    struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			    struct tc_qopt_offload_stats *stats_ptr)
{
	u64 tx_packets = 0;
	u64 tx_bytes = 0;
	u64 backlog = 0;
	u64 drops = 0;

	mlxsw_sp_qdisc_collect_tc_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
					&tx_bytes, &tx_packets,
					&drops, &backlog);
	mlxsw_sp_qdisc_update_stats(mlxsw_sp_port->mlxsw_sp, mlxsw_sp_qdisc,
				    tx_bytes, tx_packets, drops, backlog,
				    stats_ptr);
}

static int
mlxsw_sp_tclass_congestion_enable(struct mlxsw_sp_port *mlxsw_sp_port,
				  int tclass_num, u32 min, u32 max,
				  u32 probability, bool is_wred, bool is_ecn)
{
	char cwtpm_cmd[MLXSW_REG_CWTPM_LEN];
	char cwtp_cmd[MLXSW_REG_CWTP_LEN];
	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
	int err;

	mlxsw_reg_cwtp_pack(cwtp_cmd, mlxsw_sp_port->local_port, tclass_num);
	mlxsw_reg_cwtp_profile_pack(cwtp_cmd, MLXSW_REG_CWTP_DEFAULT_PROFILE,
				    roundup(min, MLXSW_REG_CWTP_MIN_VALUE),
				    roundup(max, MLXSW_REG_CWTP_MIN_VALUE),
				    probability);

	err = mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(cwtp), cwtp_cmd);
	if (err)
		return err;

	mlxsw_reg_cwtpm_pack(cwtpm_cmd, mlxsw_sp_port->local_port, tclass_num,
			     MLXSW_REG_CWTP_DEFAULT_PROFILE, is_wred, is_ecn);

	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(cwtpm), cwtpm_cmd);
}

static int
mlxsw_sp_tclass_congestion_disable(struct mlxsw_sp_port *mlxsw_sp_port,
				   int tclass_num)
{
	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
	char cwtpm_cmd[MLXSW_REG_CWTPM_LEN];

	mlxsw_reg_cwtpm_pack(cwtpm_cmd, mlxsw_sp_port->local_port, tclass_num,
			     MLXSW_REG_CWTPM_RESET_PROFILE, false, false);
	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(cwtpm), cwtpm_cmd);
}

static void
mlxsw_sp_setup_tc_qdisc_red_clean_stats(struct mlxsw_sp_port *mlxsw_sp_port,
					struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	u8 tclass_num = mlxsw_sp_qdisc->tclass_num;
	struct mlxsw_sp_qdisc_stats *stats_base;
	struct mlxsw_sp_port_xstats *xstats;
	struct red_stats *red_base;

	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;
	stats_base = &mlxsw_sp_qdisc->stats_base;
	red_base = &mlxsw_sp_qdisc->xstats_base.red;

	mlxsw_sp_qdisc_bstats_per_priority_get(xstats,
					       mlxsw_sp_qdisc->prio_bitmap,
					       &stats_base->tx_packets,
					       &stats_base->tx_bytes);
	red_base->prob_drop = xstats->wred_drop[tclass_num];
	red_base->pdrop = mlxsw_sp_xstats_tail_drop(xstats, tclass_num);

	stats_base->overlimits = red_base->prob_drop + red_base->prob_mark;
	stats_base->drops = red_base->prob_drop + red_base->pdrop;

	stats_base->backlog = 0;
}

static int
mlxsw_sp_qdisc_red_destroy(struct mlxsw_sp_port *mlxsw_sp_port,
			   struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	struct mlxsw_sp_qdisc *root_qdisc = &qdisc_state->root_qdisc;

	if (root_qdisc != mlxsw_sp_qdisc)
		root_qdisc->stats_base.backlog -=
					mlxsw_sp_qdisc->stats_base.backlog;

	return mlxsw_sp_tclass_congestion_disable(mlxsw_sp_port,
						  mlxsw_sp_qdisc->tclass_num);
}

static int
mlxsw_sp_qdisc_red_check_params(struct mlxsw_sp_port *mlxsw_sp_port,
				struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
				void *params)
{
	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
	struct tc_red_qopt_offload_params *p = params;

	if (p->min > p->max) {
		dev_err(mlxsw_sp->bus_info->dev,
			"spectrum: RED: min %u is bigger then max %u\n", p->min,
			p->max);
		return -EINVAL;
	}
	if (p->max > MLXSW_CORE_RES_GET(mlxsw_sp->core,
					GUARANTEED_SHARED_BUFFER)) {
		dev_err(mlxsw_sp->bus_info->dev,
			"spectrum: RED: max value %u is too big\n", p->max);
		return -EINVAL;
	}
	if (p->min == 0 || p->max == 0) {
		dev_err(mlxsw_sp->bus_info->dev,
			"spectrum: RED: 0 value is illegal for min and max\n");
		return -EINVAL;
	}
	return 0;
}

static int
mlxsw_sp_qdisc_red_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
			   struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			   void *params)
{
	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
	struct tc_red_qopt_offload_params *p = params;
	u8 tclass_num = mlxsw_sp_qdisc->tclass_num;
	u32 min, max;
	u64 prob;

	/* calculate probability in percentage */
	prob = p->probability;
	prob *= 100;
	prob = DIV_ROUND_UP(prob, 1 << 16);
	prob = DIV_ROUND_UP(prob, 1 << 16);
	min = mlxsw_sp_bytes_cells(mlxsw_sp, p->min);
	max = mlxsw_sp_bytes_cells(mlxsw_sp, p->max);
	return mlxsw_sp_tclass_congestion_enable(mlxsw_sp_port, tclass_num,
						 min, max, prob,
						 !p->is_nodrop, p->is_ecn);
}

static void
mlxsw_sp_qdisc_leaf_unoffload(struct mlxsw_sp_port *mlxsw_sp_port,
			      struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			      struct gnet_stats_queue *qstats)
{
	u64 backlog;

	backlog = mlxsw_sp_cells_bytes(mlxsw_sp_port->mlxsw_sp,
				       mlxsw_sp_qdisc->stats_base.backlog);
	qstats->backlog -= backlog;
	mlxsw_sp_qdisc->stats_base.backlog = 0;
}

static void
mlxsw_sp_qdisc_red_unoffload(struct mlxsw_sp_port *mlxsw_sp_port,
			     struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			     void *params)
{
	struct tc_red_qopt_offload_params *p = params;

	mlxsw_sp_qdisc_leaf_unoffload(mlxsw_sp_port, mlxsw_sp_qdisc, p->qstats);
}

static int
mlxsw_sp_qdisc_get_red_xstats(struct mlxsw_sp_port *mlxsw_sp_port,
			      struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			      void *xstats_ptr)
{
	struct red_stats *xstats_base = &mlxsw_sp_qdisc->xstats_base.red;
	u8 tclass_num = mlxsw_sp_qdisc->tclass_num;
	struct mlxsw_sp_port_xstats *xstats;
	struct red_stats *res = xstats_ptr;
	int early_drops, pdrops;

	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;

	early_drops = xstats->wred_drop[tclass_num] - xstats_base->prob_drop;
	pdrops = mlxsw_sp_xstats_tail_drop(xstats, tclass_num) -
		 xstats_base->pdrop;

	res->pdrop += pdrops;
	res->prob_drop += early_drops;

	xstats_base->pdrop += pdrops;
	xstats_base->prob_drop += early_drops;
	return 0;
}

static int
mlxsw_sp_qdisc_get_red_stats(struct mlxsw_sp_port *mlxsw_sp_port,
			     struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			     struct tc_qopt_offload_stats *stats_ptr)
{
	u8 tclass_num = mlxsw_sp_qdisc->tclass_num;
	struct mlxsw_sp_qdisc_stats *stats_base;
	struct mlxsw_sp_port_xstats *xstats;
	u64 overlimits;

	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;
	stats_base = &mlxsw_sp_qdisc->stats_base;

	mlxsw_sp_qdisc_get_tc_stats(mlxsw_sp_port, mlxsw_sp_qdisc, stats_ptr);
	overlimits = xstats->wred_drop[tclass_num] - stats_base->overlimits;

	stats_ptr->qstats->overlimits += overlimits;
	stats_base->overlimits += overlimits;

	return 0;
}

#define MLXSW_SP_PORT_DEFAULT_TCLASS 0

static struct mlxsw_sp_qdisc_ops mlxsw_sp_qdisc_ops_red = {
	.type = MLXSW_SP_QDISC_RED,
	.check_params = mlxsw_sp_qdisc_red_check_params,
	.replace = mlxsw_sp_qdisc_red_replace,
	.unoffload = mlxsw_sp_qdisc_red_unoffload,
	.destroy = mlxsw_sp_qdisc_red_destroy,
	.get_stats = mlxsw_sp_qdisc_get_red_stats,
	.get_xstats = mlxsw_sp_qdisc_get_red_xstats,
	.clean_stats = mlxsw_sp_setup_tc_qdisc_red_clean_stats,
};

int mlxsw_sp_setup_tc_red(struct mlxsw_sp_port *mlxsw_sp_port,
			  struct tc_red_qopt_offload *p)
{
	struct mlxsw_sp_qdisc *mlxsw_sp_qdisc;

	mlxsw_sp_qdisc = mlxsw_sp_qdisc_find(mlxsw_sp_port, p->parent, false);
	if (!mlxsw_sp_qdisc)
		return -EOPNOTSUPP;

	if (p->command == TC_RED_REPLACE)
		return mlxsw_sp_qdisc_replace(mlxsw_sp_port, p->handle,
					      mlxsw_sp_qdisc,
					      &mlxsw_sp_qdisc_ops_red,
					      &p->set);

	if (!mlxsw_sp_qdisc_compare(mlxsw_sp_qdisc, p->handle,
				    MLXSW_SP_QDISC_RED))
		return -EOPNOTSUPP;

	switch (p->command) {
	case TC_RED_DESTROY:
		return mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
	case TC_RED_XSTATS:
		return mlxsw_sp_qdisc_get_xstats(mlxsw_sp_port, mlxsw_sp_qdisc,
						 p->xstats);
	case TC_RED_STATS:
		return mlxsw_sp_qdisc_get_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
						&p->stats);
	default:
		return -EOPNOTSUPP;
	}
}

static void
mlxsw_sp_setup_tc_qdisc_leaf_clean_stats(struct mlxsw_sp_port *mlxsw_sp_port,
					 struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	u64 backlog_cells = 0;
	u64 tx_packets = 0;
	u64 tx_bytes = 0;
	u64 drops = 0;

	mlxsw_sp_qdisc_collect_tc_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
					&tx_bytes, &tx_packets,
					&drops, &backlog_cells);

	mlxsw_sp_qdisc->stats_base.tx_packets = tx_packets;
	mlxsw_sp_qdisc->stats_base.tx_bytes = tx_bytes;
	mlxsw_sp_qdisc->stats_base.drops = drops;
	mlxsw_sp_qdisc->stats_base.backlog = 0;
}

static int
mlxsw_sp_qdisc_tbf_destroy(struct mlxsw_sp_port *mlxsw_sp_port,
			   struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	struct mlxsw_sp_qdisc *root_qdisc = &qdisc_state->root_qdisc;

	if (root_qdisc != mlxsw_sp_qdisc)
		root_qdisc->stats_base.backlog -=
					mlxsw_sp_qdisc->stats_base.backlog;

	return mlxsw_sp_port_ets_maxrate_set(mlxsw_sp_port,
					     MLXSW_REG_QEEC_HR_SUBGROUP,
					     mlxsw_sp_qdisc->tclass_num, 0,
					     MLXSW_REG_QEEC_MAS_DIS, 0);
}

static int
mlxsw_sp_qdisc_tbf_bs(struct mlxsw_sp_port *mlxsw_sp_port,
		      u32 max_size, u8 *p_burst_size)
{
	/* TBF burst size is configured in bytes. The ASIC burst size value is
	 * ((2 ^ bs) * 512 bits. Convert the TBF bytes to 512-bit units.
	 */
	u32 bs512 = max_size / 64;
	u8 bs = fls(bs512);

	if (!bs)
		return -EINVAL;
	--bs;

	/* Demand a power of two. */
	if ((1 << bs) != bs512)
		return -EINVAL;

	if (bs < mlxsw_sp_port->mlxsw_sp->lowest_shaper_bs ||
	    bs > MLXSW_REG_QEEC_HIGHEST_SHAPER_BS)
		return -EINVAL;

	*p_burst_size = bs;
	return 0;
}

static u32
mlxsw_sp_qdisc_tbf_max_size(u8 bs)
{
	return (1U << bs) * 64;
}

static u64
mlxsw_sp_qdisc_tbf_rate_kbps(struct tc_tbf_qopt_offload_replace_params *p)
{
	/* TBF interface is in bytes/s, whereas Spectrum ASIC is configured in
	 * Kbits/s.
	 */
	return div_u64(p->rate.rate_bytes_ps, 1000) * 8;
}

static int
mlxsw_sp_qdisc_tbf_check_params(struct mlxsw_sp_port *mlxsw_sp_port,
				struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
				void *params)
{
	struct tc_tbf_qopt_offload_replace_params *p = params;
	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
	u64 rate_kbps = mlxsw_sp_qdisc_tbf_rate_kbps(p);
	u8 burst_size;
	int err;

	if (rate_kbps >= MLXSW_REG_QEEC_MAS_DIS) {
		dev_err(mlxsw_sp_port->mlxsw_sp->bus_info->dev,
			"spectrum: TBF: rate of %lluKbps must be below %u\n",
			rate_kbps, MLXSW_REG_QEEC_MAS_DIS);
		return -EINVAL;
	}

	err = mlxsw_sp_qdisc_tbf_bs(mlxsw_sp_port, p->max_size, &burst_size);
	if (err) {
		u8 highest_shaper_bs = MLXSW_REG_QEEC_HIGHEST_SHAPER_BS;

		dev_err(mlxsw_sp->bus_info->dev,
			"spectrum: TBF: invalid burst size of %u, must be a power of two between %u and %u",
			p->max_size,
			mlxsw_sp_qdisc_tbf_max_size(mlxsw_sp->lowest_shaper_bs),
			mlxsw_sp_qdisc_tbf_max_size(highest_shaper_bs));
		return -EINVAL;
	}

	return 0;
}

static int
mlxsw_sp_qdisc_tbf_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
			   struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			   void *params)
{
	struct tc_tbf_qopt_offload_replace_params *p = params;
	u64 rate_kbps = mlxsw_sp_qdisc_tbf_rate_kbps(p);
	u8 burst_size;
	int err;

	err = mlxsw_sp_qdisc_tbf_bs(mlxsw_sp_port, p->max_size, &burst_size);
	if (WARN_ON_ONCE(err))
		/* check_params above was supposed to reject this value. */
		return -EINVAL;

	/* Configure subgroup shaper, so that both UC and MC traffic is subject
	 * to shaping. That is unlike RED, however UC queue lengths are going to
	 * be different than MC ones due to different pool and quota
	 * configurations, so the configuration is not applicable. For shaper on
	 * the other hand, subjecting the overall stream to the configured
	 * shaper makes sense. Also note that that is what we do for
	 * ieee_setmaxrate().
	 */
	return mlxsw_sp_port_ets_maxrate_set(mlxsw_sp_port,
					     MLXSW_REG_QEEC_HR_SUBGROUP,
					     mlxsw_sp_qdisc->tclass_num, 0,
					     rate_kbps, burst_size);
}

static void
mlxsw_sp_qdisc_tbf_unoffload(struct mlxsw_sp_port *mlxsw_sp_port,
			     struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			     void *params)
{
	struct tc_tbf_qopt_offload_replace_params *p = params;

	mlxsw_sp_qdisc_leaf_unoffload(mlxsw_sp_port, mlxsw_sp_qdisc, p->qstats);
}

static int
mlxsw_sp_qdisc_get_tbf_stats(struct mlxsw_sp_port *mlxsw_sp_port,
			     struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			     struct tc_qopt_offload_stats *stats_ptr)
{
	mlxsw_sp_qdisc_get_tc_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
				    stats_ptr);
	return 0;
}

static struct mlxsw_sp_qdisc_ops mlxsw_sp_qdisc_ops_tbf = {
	.type = MLXSW_SP_QDISC_TBF,
	.check_params = mlxsw_sp_qdisc_tbf_check_params,
	.replace = mlxsw_sp_qdisc_tbf_replace,
	.unoffload = mlxsw_sp_qdisc_tbf_unoffload,
	.destroy = mlxsw_sp_qdisc_tbf_destroy,
	.get_stats = mlxsw_sp_qdisc_get_tbf_stats,
	.clean_stats = mlxsw_sp_setup_tc_qdisc_leaf_clean_stats,
};

int mlxsw_sp_setup_tc_tbf(struct mlxsw_sp_port *mlxsw_sp_port,
			  struct tc_tbf_qopt_offload *p)
{
	struct mlxsw_sp_qdisc *mlxsw_sp_qdisc;

	mlxsw_sp_qdisc = mlxsw_sp_qdisc_find(mlxsw_sp_port, p->parent, false);
	if (!mlxsw_sp_qdisc)
		return -EOPNOTSUPP;

	if (p->command == TC_TBF_REPLACE)
		return mlxsw_sp_qdisc_replace(mlxsw_sp_port, p->handle,
					      mlxsw_sp_qdisc,
					      &mlxsw_sp_qdisc_ops_tbf,
					      &p->replace_params);

	if (!mlxsw_sp_qdisc_compare(mlxsw_sp_qdisc, p->handle,
				    MLXSW_SP_QDISC_TBF))
		return -EOPNOTSUPP;

	switch (p->command) {
	case TC_TBF_DESTROY:
		return mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
	case TC_TBF_STATS:
		return mlxsw_sp_qdisc_get_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
						&p->stats);
	default:
		return -EOPNOTSUPP;
	}
}

static int
mlxsw_sp_qdisc_fifo_destroy(struct mlxsw_sp_port *mlxsw_sp_port,
			    struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	struct mlxsw_sp_qdisc *root_qdisc = &qdisc_state->root_qdisc;

	if (root_qdisc != mlxsw_sp_qdisc)
		root_qdisc->stats_base.backlog -=
					mlxsw_sp_qdisc->stats_base.backlog;
	return 0;
}

static int
mlxsw_sp_qdisc_fifo_check_params(struct mlxsw_sp_port *mlxsw_sp_port,
				 struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
				 void *params)
{
	return 0;
}

static int
mlxsw_sp_qdisc_fifo_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
			    struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			    void *params)
{
	return 0;
}

static int
mlxsw_sp_qdisc_get_fifo_stats(struct mlxsw_sp_port *mlxsw_sp_port,
			      struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			      struct tc_qopt_offload_stats *stats_ptr)
{
	mlxsw_sp_qdisc_get_tc_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
				    stats_ptr);
	return 0;
}

static struct mlxsw_sp_qdisc_ops mlxsw_sp_qdisc_ops_fifo = {
	.type = MLXSW_SP_QDISC_FIFO,
	.check_params = mlxsw_sp_qdisc_fifo_check_params,
	.replace = mlxsw_sp_qdisc_fifo_replace,
	.destroy = mlxsw_sp_qdisc_fifo_destroy,
	.get_stats = mlxsw_sp_qdisc_get_fifo_stats,
	.clean_stats = mlxsw_sp_setup_tc_qdisc_leaf_clean_stats,
};

int mlxsw_sp_setup_tc_fifo(struct mlxsw_sp_port *mlxsw_sp_port,
			   struct tc_fifo_qopt_offload *p)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	struct mlxsw_sp_qdisc *mlxsw_sp_qdisc;
	int tclass, child_index;
	u32 parent_handle;

	/* Invisible FIFOs are tracked in future_handle and future_fifos. Make
	 * sure that not more than one qdisc is created for a port at a time.
	 * RTNL is a simple proxy for that.
	 */
	ASSERT_RTNL();

	mlxsw_sp_qdisc = mlxsw_sp_qdisc_find(mlxsw_sp_port, p->parent, false);
	if (!mlxsw_sp_qdisc && p->handle == TC_H_UNSPEC) {
		parent_handle = TC_H_MAJ(p->parent);
		if (parent_handle != qdisc_state->future_handle) {
			/* This notifications is for a different Qdisc than
			 * previously. Wipe the future cache.
			 */
			memset(qdisc_state->future_fifos, 0,
			       sizeof(qdisc_state->future_fifos));
			qdisc_state->future_handle = parent_handle;
		}

		child_index = TC_H_MIN(p->parent);
		tclass = MLXSW_SP_PRIO_CHILD_TO_TCLASS(child_index);
		if (tclass < IEEE_8021QAZ_MAX_TCS) {
			if (p->command == TC_FIFO_REPLACE)
				qdisc_state->future_fifos[tclass] = true;
			else if (p->command == TC_FIFO_DESTROY)
				qdisc_state->future_fifos[tclass] = false;
		}
	}
	if (!mlxsw_sp_qdisc)
		return -EOPNOTSUPP;

	if (p->command == TC_FIFO_REPLACE) {
		return mlxsw_sp_qdisc_replace(mlxsw_sp_port, p->handle,
					      mlxsw_sp_qdisc,
					      &mlxsw_sp_qdisc_ops_fifo, NULL);
	}

	if (!mlxsw_sp_qdisc_compare(mlxsw_sp_qdisc, p->handle,
				    MLXSW_SP_QDISC_FIFO))
		return -EOPNOTSUPP;

	switch (p->command) {
	case TC_FIFO_DESTROY:
		if (p->handle == mlxsw_sp_qdisc->handle)
			return mlxsw_sp_qdisc_destroy(mlxsw_sp_port,
						      mlxsw_sp_qdisc);
		return 0;
	case TC_FIFO_STATS:
		return mlxsw_sp_qdisc_get_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
						&p->stats);
	case TC_FIFO_REPLACE: /* Handled above. */
		break;
	}

	return -EOPNOTSUPP;
}

static int
__mlxsw_sp_qdisc_ets_destroy(struct mlxsw_sp_port *mlxsw_sp_port)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	int i;

	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
		mlxsw_sp_port_prio_tc_set(mlxsw_sp_port, i,
					  MLXSW_SP_PORT_DEFAULT_TCLASS);
		mlxsw_sp_port_ets_set(mlxsw_sp_port,
				      MLXSW_REG_QEEC_HR_SUBGROUP,
				      i, 0, false, 0);
		mlxsw_sp_qdisc_destroy(mlxsw_sp_port,
				       &qdisc_state->tclass_qdiscs[i]);
		qdisc_state->tclass_qdiscs[i].prio_bitmap = 0;
	}

	return 0;
}

static int
mlxsw_sp_qdisc_prio_destroy(struct mlxsw_sp_port *mlxsw_sp_port,
			    struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	return __mlxsw_sp_qdisc_ets_destroy(mlxsw_sp_port);
}

static int
__mlxsw_sp_qdisc_ets_check_params(unsigned int nbands)
{
	if (nbands > IEEE_8021QAZ_MAX_TCS)
		return -EOPNOTSUPP;

	return 0;
}

static int
mlxsw_sp_qdisc_prio_check_params(struct mlxsw_sp_port *mlxsw_sp_port,
				 struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
				 void *params)
{
	struct tc_prio_qopt_offload_params *p = params;

	return __mlxsw_sp_qdisc_ets_check_params(p->bands);
}

static int
__mlxsw_sp_qdisc_ets_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
			     unsigned int nbands,
			     const unsigned int *quanta,
			     const unsigned int *weights,
			     const u8 *priomap)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	struct mlxsw_sp_qdisc *child_qdisc;
	int tclass, i, band, backlog;
	u8 old_priomap;
	int err;

	for (band = 0; band < nbands; band++) {
		tclass = MLXSW_SP_PRIO_BAND_TO_TCLASS(band);
		child_qdisc = &qdisc_state->tclass_qdiscs[tclass];
		old_priomap = child_qdisc->prio_bitmap;
		child_qdisc->prio_bitmap = 0;

		err = mlxsw_sp_port_ets_set(mlxsw_sp_port,
					    MLXSW_REG_QEEC_HR_SUBGROUP,
					    tclass, 0, !!quanta[band],
					    weights[band]);
		if (err)
			return err;

		for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
			if (priomap[i] == band) {
				child_qdisc->prio_bitmap |= BIT(i);
				if (BIT(i) & old_priomap)
					continue;
				err = mlxsw_sp_port_prio_tc_set(mlxsw_sp_port,
								i, tclass);
				if (err)
					return err;
			}
		}
		if (old_priomap != child_qdisc->prio_bitmap &&
		    child_qdisc->ops && child_qdisc->ops->clean_stats) {
			backlog = child_qdisc->stats_base.backlog;
			child_qdisc->ops->clean_stats(mlxsw_sp_port,
						      child_qdisc);
			child_qdisc->stats_base.backlog = backlog;
		}

		if (handle == qdisc_state->future_handle &&
		    qdisc_state->future_fifos[tclass]) {
			err = mlxsw_sp_qdisc_replace(mlxsw_sp_port, TC_H_UNSPEC,
						     child_qdisc,
						     &mlxsw_sp_qdisc_ops_fifo,
						     NULL);
			if (err)
				return err;
		}
	}
	for (; band < IEEE_8021QAZ_MAX_TCS; band++) {
		tclass = MLXSW_SP_PRIO_BAND_TO_TCLASS(band);
		child_qdisc = &qdisc_state->tclass_qdiscs[tclass];
		child_qdisc->prio_bitmap = 0;
		mlxsw_sp_qdisc_destroy(mlxsw_sp_port, child_qdisc);
		mlxsw_sp_port_ets_set(mlxsw_sp_port,
				      MLXSW_REG_QEEC_HR_SUBGROUP,
				      tclass, 0, false, 0);
	}

	qdisc_state->future_handle = TC_H_UNSPEC;
	memset(qdisc_state->future_fifos, 0, sizeof(qdisc_state->future_fifos));
	return 0;
}

static int
mlxsw_sp_qdisc_prio_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
			    struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			    void *params)
{
	struct tc_prio_qopt_offload_params *p = params;
	unsigned int zeroes[TCQ_ETS_MAX_BANDS] = {0};

	return __mlxsw_sp_qdisc_ets_replace(mlxsw_sp_port, handle, p->bands,
					    zeroes, zeroes, p->priomap);
}

static void
__mlxsw_sp_qdisc_ets_unoffload(struct mlxsw_sp_port *mlxsw_sp_port,
			       struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			       struct gnet_stats_queue *qstats)
{
	u64 backlog;

	backlog = mlxsw_sp_cells_bytes(mlxsw_sp_port->mlxsw_sp,
				       mlxsw_sp_qdisc->stats_base.backlog);
	qstats->backlog -= backlog;
}

static void
mlxsw_sp_qdisc_prio_unoffload(struct mlxsw_sp_port *mlxsw_sp_port,
			      struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			      void *params)
{
	struct tc_prio_qopt_offload_params *p = params;

	__mlxsw_sp_qdisc_ets_unoffload(mlxsw_sp_port, mlxsw_sp_qdisc,
				       p->qstats);
}

static int
mlxsw_sp_qdisc_get_prio_stats(struct mlxsw_sp_port *mlxsw_sp_port,
			      struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			      struct tc_qopt_offload_stats *stats_ptr)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	struct mlxsw_sp_qdisc *tc_qdisc;
	u64 tx_packets = 0;
	u64 tx_bytes = 0;
	u64 backlog = 0;
	u64 drops = 0;
	int i;

	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
		tc_qdisc = &qdisc_state->tclass_qdiscs[i];
		mlxsw_sp_qdisc_collect_tc_stats(mlxsw_sp_port, tc_qdisc,
						&tx_bytes, &tx_packets,
						&drops, &backlog);
	}

	mlxsw_sp_qdisc_update_stats(mlxsw_sp_port->mlxsw_sp, mlxsw_sp_qdisc,
				    tx_bytes, tx_packets, drops, backlog,
				    stats_ptr);
	return 0;
}

static void
mlxsw_sp_setup_tc_qdisc_prio_clean_stats(struct mlxsw_sp_port *mlxsw_sp_port,
					 struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	struct mlxsw_sp_qdisc_stats *stats_base;
	struct mlxsw_sp_port_xstats *xstats;
	struct rtnl_link_stats64 *stats;
	int i;

	xstats = &mlxsw_sp_port->periodic_hw_stats.xstats;
	stats = &mlxsw_sp_port->periodic_hw_stats.stats;
	stats_base = &mlxsw_sp_qdisc->stats_base;

	stats_base->tx_packets = stats->tx_packets;
	stats_base->tx_bytes = stats->tx_bytes;

	stats_base->drops = 0;
	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
		stats_base->drops += mlxsw_sp_xstats_tail_drop(xstats, i);
		stats_base->drops += xstats->wred_drop[i];
	}

	mlxsw_sp_qdisc->stats_base.backlog = 0;
}

static struct mlxsw_sp_qdisc_ops mlxsw_sp_qdisc_ops_prio = {
	.type = MLXSW_SP_QDISC_PRIO,
	.check_params = mlxsw_sp_qdisc_prio_check_params,
	.replace = mlxsw_sp_qdisc_prio_replace,
	.unoffload = mlxsw_sp_qdisc_prio_unoffload,
	.destroy = mlxsw_sp_qdisc_prio_destroy,
	.get_stats = mlxsw_sp_qdisc_get_prio_stats,
	.clean_stats = mlxsw_sp_setup_tc_qdisc_prio_clean_stats,
};

static int
mlxsw_sp_qdisc_ets_check_params(struct mlxsw_sp_port *mlxsw_sp_port,
				struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
				void *params)
{
	struct tc_ets_qopt_offload_replace_params *p = params;

	return __mlxsw_sp_qdisc_ets_check_params(p->bands);
}

static int
mlxsw_sp_qdisc_ets_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
			   struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			   void *params)
{
	struct tc_ets_qopt_offload_replace_params *p = params;

	return __mlxsw_sp_qdisc_ets_replace(mlxsw_sp_port, handle, p->bands,
					    p->quanta, p->weights, p->priomap);
}

static void
mlxsw_sp_qdisc_ets_unoffload(struct mlxsw_sp_port *mlxsw_sp_port,
			     struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			     void *params)
{
	struct tc_ets_qopt_offload_replace_params *p = params;

	__mlxsw_sp_qdisc_ets_unoffload(mlxsw_sp_port, mlxsw_sp_qdisc,
				       p->qstats);
}

static int
mlxsw_sp_qdisc_ets_destroy(struct mlxsw_sp_port *mlxsw_sp_port,
			   struct mlxsw_sp_qdisc *mlxsw_sp_qdisc)
{
	return __mlxsw_sp_qdisc_ets_destroy(mlxsw_sp_port);
}

static struct mlxsw_sp_qdisc_ops mlxsw_sp_qdisc_ops_ets = {
	.type = MLXSW_SP_QDISC_ETS,
	.check_params = mlxsw_sp_qdisc_ets_check_params,
	.replace = mlxsw_sp_qdisc_ets_replace,
	.unoffload = mlxsw_sp_qdisc_ets_unoffload,
	.destroy = mlxsw_sp_qdisc_ets_destroy,
	.get_stats = mlxsw_sp_qdisc_get_prio_stats,
	.clean_stats = mlxsw_sp_setup_tc_qdisc_prio_clean_stats,
};

/* Linux allows linking of Qdiscs to arbitrary classes (so long as the resulting
 * graph is free of cycles). These operations do not change the parent handle
 * though, which means it can be incomplete (if there is more than one class
 * where the Qdisc in question is grafted) or outright wrong (if the Qdisc was
 * linked to a different class and then removed from the original class).
 *
 * E.g. consider this sequence of operations:
 *
 *  # tc qdisc add dev swp1 root handle 1: prio
 *  # tc qdisc add dev swp1 parent 1:3 handle 13: red limit 1000000 avpkt 10000
 *  RED: set bandwidth to 10Mbit
 *  # tc qdisc link dev swp1 handle 13: parent 1:2
 *
 * At this point, both 1:2 and 1:3 have the same RED Qdisc instance as their
 * child. But RED will still only claim that 1:3 is its parent. If it's removed
 * from that band, its only parent will be 1:2, but it will continue to claim
 * that it is in fact 1:3.
 *
 * The notification for child Qdisc replace (e.g. TC_RED_REPLACE) comes before
 * the notification for parent graft (e.g. TC_PRIO_GRAFT). We take the replace
 * notification to offload the child Qdisc, based on its parent handle, and use
 * the graft operation to validate that the class where the child is actually
 * grafted corresponds to the parent handle. If the two don't match, we
 * unoffload the child.
 */
static int
__mlxsw_sp_qdisc_ets_graft(struct mlxsw_sp_port *mlxsw_sp_port,
			   struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			   u8 band, u32 child_handle)
{
	struct mlxsw_sp_qdisc_state *qdisc_state = mlxsw_sp_port->qdisc;
	int tclass_num = MLXSW_SP_PRIO_BAND_TO_TCLASS(band);
	struct mlxsw_sp_qdisc *old_qdisc;

	if (band < IEEE_8021QAZ_MAX_TCS &&
	    qdisc_state->tclass_qdiscs[tclass_num].handle == child_handle)
		return 0;

	if (!child_handle) {
		/* This is an invisible FIFO replacing the original Qdisc.
		 * Ignore it--the original Qdisc's destroy will follow.
		 */
		return 0;
	}

	/* See if the grafted qdisc is already offloaded on any tclass. If so,
	 * unoffload it.
	 */
	old_qdisc = mlxsw_sp_qdisc_find_by_handle(mlxsw_sp_port,
						  child_handle);
	if (old_qdisc)
		mlxsw_sp_qdisc_destroy(mlxsw_sp_port, old_qdisc);

	mlxsw_sp_qdisc_destroy(mlxsw_sp_port,
			       &qdisc_state->tclass_qdiscs[tclass_num]);
	return -EOPNOTSUPP;
}

static int
mlxsw_sp_qdisc_prio_graft(struct mlxsw_sp_port *mlxsw_sp_port,
			  struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
			  struct tc_prio_qopt_offload_graft_params *p)
{
	return __mlxsw_sp_qdisc_ets_graft(mlxsw_sp_port, mlxsw_sp_qdisc,
					  p->band, p->child_handle);
}

int mlxsw_sp_setup_tc_prio(struct mlxsw_sp_port *mlxsw_sp_port,
			   struct tc_prio_qopt_offload *p)
{
	struct mlxsw_sp_qdisc *mlxsw_sp_qdisc;

	mlxsw_sp_qdisc = mlxsw_sp_qdisc_find(mlxsw_sp_port, p->parent, true);
	if (!mlxsw_sp_qdisc)
		return -EOPNOTSUPP;

	if (p->command == TC_PRIO_REPLACE)
		return mlxsw_sp_qdisc_replace(mlxsw_sp_port, p->handle,
					      mlxsw_sp_qdisc,
					      &mlxsw_sp_qdisc_ops_prio,
					      &p->replace_params);

	if (!mlxsw_sp_qdisc_compare(mlxsw_sp_qdisc, p->handle,
				    MLXSW_SP_QDISC_PRIO))
		return -EOPNOTSUPP;

	switch (p->command) {
	case TC_PRIO_DESTROY:
		return mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
	case TC_PRIO_STATS:
		return mlxsw_sp_qdisc_get_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
						&p->stats);
	case TC_PRIO_GRAFT:
		return mlxsw_sp_qdisc_prio_graft(mlxsw_sp_port, mlxsw_sp_qdisc,
						 &p->graft_params);
	default:
		return -EOPNOTSUPP;
	}
}

int mlxsw_sp_setup_tc_ets(struct mlxsw_sp_port *mlxsw_sp_port,
			  struct tc_ets_qopt_offload *p)
{
	struct mlxsw_sp_qdisc *mlxsw_sp_qdisc;

	mlxsw_sp_qdisc = mlxsw_sp_qdisc_find(mlxsw_sp_port, p->parent, true);
	if (!mlxsw_sp_qdisc)
		return -EOPNOTSUPP;

	if (p->command == TC_ETS_REPLACE)
		return mlxsw_sp_qdisc_replace(mlxsw_sp_port, p->handle,
					      mlxsw_sp_qdisc,
					      &mlxsw_sp_qdisc_ops_ets,
					      &p->replace_params);

	if (!mlxsw_sp_qdisc_compare(mlxsw_sp_qdisc, p->handle,
				    MLXSW_SP_QDISC_ETS))
		return -EOPNOTSUPP;

	switch (p->command) {
	case TC_ETS_DESTROY:
		return mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
	case TC_ETS_STATS:
		return mlxsw_sp_qdisc_get_stats(mlxsw_sp_port, mlxsw_sp_qdisc,
						&p->stats);
	case TC_ETS_GRAFT:
		return __mlxsw_sp_qdisc_ets_graft(mlxsw_sp_port, mlxsw_sp_qdisc,
						  p->graft_params.band,
						  p->graft_params.child_handle);
	default:
		return -EOPNOTSUPP;
	}
}

int mlxsw_sp_tc_qdisc_init(struct mlxsw_sp_port *mlxsw_sp_port)
{
	struct mlxsw_sp_qdisc_state *qdisc_state;
	int i;

	qdisc_state = kzalloc(sizeof(*qdisc_state), GFP_KERNEL);
	if (!qdisc_state)
		return -ENOMEM;

	qdisc_state->root_qdisc.prio_bitmap = 0xff;
	qdisc_state->root_qdisc.tclass_num = MLXSW_SP_PORT_DEFAULT_TCLASS;
	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++)
		qdisc_state->tclass_qdiscs[i].tclass_num = i;

	mlxsw_sp_port->qdisc = qdisc_state;
	return 0;
}

void mlxsw_sp_tc_qdisc_fini(struct mlxsw_sp_port *mlxsw_sp_port)
{
	kfree(mlxsw_sp_port->qdisc);
}