xref: /freebsd/sys/dev/cxgbe/t4_sched.c (revision 954712e8f62273ec4c25d05cf56c23fd670d79c0)

/*-
 * Copyright (c) 2017 Chelsio Communications, Inc.
 * All rights reserved.
 * Written by: Navdeep Parhar <np@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ratelimit.h"

#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/sbuf.h>
#include <sys/taskqueue.h>
#include <sys/sysctl.h>

#include "common/common.h"
#include "common/t4_regs.h"
#include "common/t4_regs_values.h"
#include "common/t4_msg.h"

static int
in_range(int val, int lo, int hi)
{

	return (val < 0 || (val <= hi && val >= lo));
}

static int
set_sched_class_config(struct adapter *sc, int minmax)
{
	int rc;

	if (minmax < 0)
		return (EINVAL);

	rc = begin_synchronized_op(sc, NULL, SLEEP_OK | INTR_OK, "t4sscc");
	if (rc)
		return (rc);
	if (hw_off_limits(sc))
		rc = ENXIO;
	else
		rc = -t4_sched_config(sc, FW_SCHED_TYPE_PKTSCHED, minmax, 1);
	end_synchronized_op(sc, 0);

	return (rc);
}

static int
set_sched_class_params(struct adapter *sc, struct t4_sched_class_params *p,
    int sleep_ok)
{
	int rc, top_speed, fw_level, fw_mode, fw_rateunit, fw_ratemode;
	struct port_info *pi;
	struct tx_cl_rl_params *tc, old;
	bool check_pktsize = false;

	if (p->level == SCHED_CLASS_LEVEL_CL_RL)
		fw_level = FW_SCHED_PARAMS_LEVEL_CL_RL;
	else if (p->level == SCHED_CLASS_LEVEL_CL_WRR)
		fw_level = FW_SCHED_PARAMS_LEVEL_CL_WRR;
	else if (p->level == SCHED_CLASS_LEVEL_CH_RL)
		fw_level = FW_SCHED_PARAMS_LEVEL_CH_RL;
	else
		return (EINVAL);

	if (p->level == SCHED_CLASS_LEVEL_CL_RL) {
		if (p->mode == SCHED_CLASS_MODE_CLASS)
			fw_mode = FW_SCHED_PARAMS_MODE_CLASS;
		else if (p->mode == SCHED_CLASS_MODE_FLOW) {
			check_pktsize = true;
			fw_mode = FW_SCHED_PARAMS_MODE_FLOW;
		} else
			return (EINVAL);
	} else
		fw_mode = 0;

	/* Valid channel must always be provided. */
	if (p->channel < 0)
		return (EINVAL);
	if (!in_range(p->channel, 0, sc->chip_params->nchan - 1))
		return (ERANGE);

	pi = sc->port[sc->chan_map[p->channel]];
	if (pi == NULL)
		return (ENXIO);
	MPASS(pi->tx_chan == p->channel);
	top_speed = port_top_speed(pi) * 1000000; /* Gbps -> Kbps */

	if (p->level == SCHED_CLASS_LEVEL_CL_RL ||
	    p->level == SCHED_CLASS_LEVEL_CH_RL) {
		/*
		 * Valid rate (mode, unit and values) must be provided.
		 */

		if (p->minrate < 0)
			p->minrate = 0;
		if (p->maxrate < 0)
			return (EINVAL);

		if (p->rateunit == SCHED_CLASS_RATEUNIT_BITS) {
			fw_rateunit = FW_SCHED_PARAMS_UNIT_BITRATE;
			/* ratemode could be relative (%) or absolute. */
			if (p->ratemode == SCHED_CLASS_RATEMODE_REL) {
				fw_ratemode = FW_SCHED_PARAMS_RATE_REL;
				/* maxrate is % of port bandwidth. */
				if (!in_range(p->minrate, 0, 100) ||
				    !in_range(p->maxrate, 0, 100)) {
					return (ERANGE);
				}
			} else if (p->ratemode == SCHED_CLASS_RATEMODE_ABS) {
				fw_ratemode = FW_SCHED_PARAMS_RATE_ABS;
				/* maxrate is absolute value in kbps. */
				if (!in_range(p->minrate, 0, top_speed) ||
				    !in_range(p->maxrate, 0, top_speed)) {
					return (ERANGE);
				}
			} else
				return (EINVAL);
		} else if (p->rateunit == SCHED_CLASS_RATEUNIT_PKTS) {
			/* maxrate is the absolute value in pps. */
			check_pktsize = true;
			fw_rateunit = FW_SCHED_PARAMS_UNIT_PKTRATE;
		} else
			return (EINVAL);
	} else {
		MPASS(p->level == SCHED_CLASS_LEVEL_CL_WRR);

		/*
		 * Valid weight must be provided.
		 */
		if (p->weight < 0)
		       return (EINVAL);
		if (!in_range(p->weight, 1, 99))
			return (ERANGE);

		fw_rateunit = 0;
		fw_ratemode = 0;
	}

	if (p->level == SCHED_CLASS_LEVEL_CL_RL ||
	    p->level == SCHED_CLASS_LEVEL_CL_WRR) {
		/*
		 * Valid scheduling class must be provided.
		 */
		if (p->cl < 0)
			return (EINVAL);
		if (!in_range(p->cl, 0, sc->params.nsched_cls - 1))
			return (ERANGE);
	}

	if (check_pktsize) {
		if (p->pktsize < 0)
			return (EINVAL);
		if (!in_range(p->pktsize, 64, if_getmtu(pi->vi[0].ifp)))
			return (ERANGE);
	}

	if (p->level == SCHED_CLASS_LEVEL_CL_RL) {
		tc = &pi->sched_params->cl_rl[p->cl];
		mtx_lock(&sc->tc_lock);
		if (tc->refcount > 0 || tc->state == CS_HW_UPDATE_IN_PROGRESS)
			rc = EBUSY;
		else {
			old = *tc;

			tc->flags |= CF_USER;
			tc->state = CS_HW_UPDATE_IN_PROGRESS;
			tc->ratemode = fw_ratemode;
			tc->rateunit = fw_rateunit;
			tc->mode = fw_mode;
			tc->maxrate = p->maxrate;
			tc->pktsize = p->pktsize;
			rc = 0;
		}
		mtx_unlock(&sc->tc_lock);
		if (rc != 0)
			return (rc);
	}

	rc = begin_synchronized_op(sc, NULL,
	    sleep_ok ? (SLEEP_OK | INTR_OK) : HOLD_LOCK, "t4sscp");
	if (rc != 0) {
		if (p->level == SCHED_CLASS_LEVEL_CL_RL) {
			mtx_lock(&sc->tc_lock);
			MPASS(tc->refcount == 0);
			MPASS(tc->flags & CF_USER);
			MPASS(tc->state == CS_HW_UPDATE_IN_PROGRESS);
			*tc = old;
			mtx_unlock(&sc->tc_lock);
		}
		return (rc);
	}
	if (!hw_off_limits(sc)) {
		rc = -t4_sched_params(sc, FW_SCHED_TYPE_PKTSCHED, fw_level,
		    fw_mode, fw_rateunit, fw_ratemode, p->channel, p->cl,
		    p->minrate, p->maxrate, p->weight, p->pktsize, 0, sleep_ok);
	}
	end_synchronized_op(sc, sleep_ok ? 0 : LOCK_HELD);

	if (p->level == SCHED_CLASS_LEVEL_CL_RL) {
		mtx_lock(&sc->tc_lock);
		MPASS(tc->refcount == 0);
		MPASS(tc->flags & CF_USER);
		MPASS(tc->state == CS_HW_UPDATE_IN_PROGRESS);

		if (rc == 0)
			tc->state = CS_HW_CONFIGURED;
		else {
			/* parameters failed so we don't park at params_set */
			tc->state = CS_UNINITIALIZED;
			tc->flags &= ~CF_USER;
			CH_ERR(pi, "failed to configure traffic class %d: %d.  "
			    "params: mode %d, rateunit %d, ratemode %d, "
			    "channel %d, minrate %d, maxrate %d, pktsize %d, "
			    "burstsize %d\n", p->cl, rc, fw_mode, fw_rateunit,
			    fw_ratemode, p->channel, p->minrate, p->maxrate,
			    p->pktsize, 0);
		}
		mtx_unlock(&sc->tc_lock);
	}

	return (rc);
}

static void
update_tx_sched(void *context, int pending)
{
	int i, j, rc;
	struct port_info *pi;
	struct tx_cl_rl_params *tc;
	struct adapter *sc = context;
	const int n = sc->params.nsched_cls;

	mtx_lock(&sc->tc_lock);
	for_each_port(sc, i) {
		pi = sc->port[i];
		tc = &pi->sched_params->cl_rl[0];
		for (j = 0; j < n; j++, tc++) {
			MPASS(mtx_owned(&sc->tc_lock));
			if (tc->state != CS_HW_UPDATE_REQUESTED)
				continue;
			mtx_unlock(&sc->tc_lock);

			if (begin_synchronized_op(sc, NULL, SLEEP_OK | INTR_OK,
			    "t4utxs") != 0) {
				mtx_lock(&sc->tc_lock);
				continue;
			}
			rc = -t4_sched_params(sc, FW_SCHED_TYPE_PKTSCHED,
			    FW_SCHED_PARAMS_LEVEL_CL_RL, tc->mode, tc->rateunit,
			    tc->ratemode, pi->tx_chan, j, 0, tc->maxrate, 0,
			    tc->pktsize, tc->burstsize, 1);
			end_synchronized_op(sc, 0);

			mtx_lock(&sc->tc_lock);
			MPASS(tc->state == CS_HW_UPDATE_REQUESTED);
			if (rc == 0) {
				tc->state = CS_HW_CONFIGURED;
				continue;
			}
			/* parameters failed so we try to avoid params_set */
			if (tc->refcount > 0)
				tc->state = CS_PARAMS_SET;
			else
				tc->state = CS_UNINITIALIZED;
			CH_ERR(pi, "failed to configure traffic class %d: %d.  "
			    "params: mode %d, rateunit %d, ratemode %d, "
			    "channel %d, minrate %d, maxrate %d, pktsize %d, "
			    "burstsize %d\n", j, rc, tc->mode, tc->rateunit,
			    tc->ratemode, pi->tx_chan, 0, tc->maxrate,
			    tc->pktsize, tc->burstsize);
		}
	}
	mtx_unlock(&sc->tc_lock);
}

int
t4_set_sched_class(struct adapter *sc, struct t4_sched_params *p)
{

	if (p->type != SCHED_CLASS_TYPE_PACKET)
		return (EINVAL);

	if (p->subcmd == SCHED_CLASS_SUBCMD_CONFIG)
		return (set_sched_class_config(sc, p->u.config.minmax));

	if (p->subcmd == SCHED_CLASS_SUBCMD_PARAMS)
		return (set_sched_class_params(sc, &p->u.params, 1));

	return (EINVAL);
}

static int
bind_txq_to_traffic_class(struct adapter *sc, struct sge_txq *txq, int idx)
{
	struct tx_cl_rl_params *tc0, *tc;
	int rc, old_idx;
	uint32_t fw_mnem, fw_class;

	if (!(txq->eq.flags & EQ_HW_ALLOCATED))
		return (ENXIO);

	mtx_lock(&sc->tc_lock);
	if (txq->tc_idx == -2) {
		rc = EBUSY;	/* Another bind/unbind in progress already. */
		goto done;
	}
	if (idx == txq->tc_idx) {
		rc = 0;		/* No change, nothing to do. */
		goto done;
	}

	tc0 = &sc->port[txq->eq.tx_chan]->sched_params->cl_rl[0];
	if (idx != -1) {
		/*
		 * Bind to a different class at index idx.
		 */
		tc = &tc0[idx];
		if (tc->state != CS_HW_CONFIGURED) {
			rc = ENXIO;
			goto done;
		} else {
			/*
			 * Ok to proceed.  Place a reference on the new class
			 * while still holding on to the reference on the
			 * previous class, if any.
			 */
			tc->refcount++;
		}
	}
	/* Mark as busy before letting go of the lock. */
	old_idx = txq->tc_idx;
	txq->tc_idx = -2;
	mtx_unlock(&sc->tc_lock);

	rc = begin_synchronized_op(sc, NULL, SLEEP_OK | INTR_OK, "t4btxq");
	if (rc == 0) {
		fw_mnem = (V_FW_PARAMS_MNEM(FW_PARAMS_MNEM_DMAQ) |
		    V_FW_PARAMS_PARAM_X(FW_PARAMS_PARAM_DMAQ_EQ_SCHEDCLASS_ETH) |
		    V_FW_PARAMS_PARAM_YZ(txq->eq.cntxt_id));
		fw_class = idx < 0 ? 0xffffffff : idx;
		rc = -t4_set_params(sc, sc->mbox, sc->pf, 0, 1, &fw_mnem,
		    &fw_class);
		end_synchronized_op(sc, 0);
	}

	mtx_lock(&sc->tc_lock);
	MPASS(txq->tc_idx == -2);
	if (rc == 0) {
		/*
		 * Unbind, bind, or bind to a different class succeeded.  Remove
		 * the reference on the old traffic class, if any.
		 */
		if (old_idx != -1) {
			tc = &tc0[old_idx];
			MPASS(tc->refcount > 0);
			tc->refcount--;
		}
		txq->tc_idx = idx;
	} else {
		/*
		 * Unbind, bind, or bind to a different class failed.  Remove
		 * the anticipatory reference on the new traffic class, if any.
		 */
		if (idx != -1) {
			tc = &tc0[idx];
			MPASS(tc->refcount > 0);
			tc->refcount--;
		}
		txq->tc_idx = old_idx;
	}
done:
	MPASS(txq->tc_idx >= -1 && txq->tc_idx < sc->params.nsched_cls);
	mtx_unlock(&sc->tc_lock);
	return (rc);
}

int
t4_set_sched_queue(struct adapter *sc, struct t4_sched_queue *p)
{
	struct port_info *pi = NULL;
	struct vi_info *vi;
	struct sge_txq *txq;
	int i, rc;

	if (p->port >= sc->params.nports)
		return (EINVAL);

	/*
	 * XXX: cxgbetool allows the user to specify the physical port only.  So
	 * we always operate on the main VI.
	 */
	pi = sc->port[p->port];
	vi = &pi->vi[0];

	/* Checking VI_INIT_DONE outside a synch-op is a harmless race here. */
	if (!(vi->flags & VI_INIT_DONE))
		return (EAGAIN);
	MPASS(vi->ntxq > 0);

	if (!in_range(p->queue, 0, vi->ntxq - 1) ||
	    !in_range(p->cl, 0, sc->params.nsched_cls - 1))
		return (EINVAL);

	if (p->queue < 0) {
		/*
		 * Change the scheduling on all the TX queues for the
		 * interface.
		 */
		for_each_txq(vi, i, txq) {
			rc = bind_txq_to_traffic_class(sc, txq, p->cl);
			if (rc != 0)
				break;
		}
	} else {
		/*
		 * If op.queue is non-negative, then we're only changing the
		 * scheduling on a single specified TX queue.
		 */
		txq = &sc->sge.txq[vi->first_txq + p->queue];
		rc = bind_txq_to_traffic_class(sc, txq, p->cl);
	}

	return (rc);
}

int
t4_init_tx_sched(struct adapter *sc)
{
	int i;
	const int n = sc->params.nsched_cls;
	struct port_info *pi;

	mtx_init(&sc->tc_lock, "tx_sched lock", NULL, MTX_DEF);
	TASK_INIT(&sc->tc_task, 0, update_tx_sched, sc);
	for_each_port(sc, i) {
		pi = sc->port[i];
		pi->sched_params = malloc(sizeof(*pi->sched_params) +
		    n * sizeof(struct tx_cl_rl_params), M_CXGBE, M_ZERO | M_WAITOK);
	}

	return (0);
}

int
t4_free_tx_sched(struct adapter *sc)
{
	int i;

	taskqueue_drain(taskqueue_thread, &sc->tc_task);

	for_each_port(sc, i) {
		if (sc->port[i] != NULL)
			free(sc->port[i]->sched_params, M_CXGBE);
	}

	if (mtx_initialized(&sc->tc_lock))
		mtx_destroy(&sc->tc_lock);

	return (0);
}

void
t4_update_tx_sched(struct adapter *sc)
{

	taskqueue_enqueue(taskqueue_thread, &sc->tc_task);
}

int
t4_reserve_cl_rl_kbps(struct adapter *sc, int port_id, u_int maxrate,
    int *tc_idx)
{
	int rc = 0, fa, fa2, i, pktsize, burstsize;
	bool update;
	struct tx_cl_rl_params *tc;
	struct port_info *pi;

	MPASS(port_id >= 0 && port_id < sc->params.nports);

	pi = sc->port[port_id];
	if (pi->sched_params->pktsize > 0)
		pktsize = pi->sched_params->pktsize;
	else
		pktsize = if_getmtu(pi->vi[0].ifp);
	if (pi->sched_params->burstsize > 0)
		burstsize = pi->sched_params->burstsize;
	else
		burstsize = pktsize * 4;
	tc = &pi->sched_params->cl_rl[0];

	update = false;
	fa = fa2 = -1;
	mtx_lock(&sc->tc_lock);
	for (i = 0; i < sc->params.nsched_cls; i++, tc++) {
		if (tc->state >= CS_PARAMS_SET &&
		    tc->ratemode == FW_SCHED_PARAMS_RATE_ABS &&
		    tc->rateunit == FW_SCHED_PARAMS_UNIT_BITRATE &&
		    tc->mode == FW_SCHED_PARAMS_MODE_FLOW &&
		    tc->maxrate == maxrate && tc->pktsize == pktsize &&
		    tc->burstsize == burstsize) {
			tc->refcount++;
			*tc_idx = i;
			if (tc->state == CS_PARAMS_SET) {
				tc->state = CS_HW_UPDATE_REQUESTED;
				update = true;
			}
			goto done;
		}

		if (fa < 0 && tc->state == CS_UNINITIALIZED) {
			MPASS(tc->refcount == 0);
			fa = i;		/* first available, never used. */
		}
		if (fa2 < 0 && tc->refcount == 0 && !(tc->flags & CF_USER)) {
			fa2 = i;	/* first available, used previously.  */
		}
	}
	/* Not found */
	MPASS(i == sc->params.nsched_cls);
	if (fa == -1)
		fa = fa2;
	if (fa == -1) {
		*tc_idx = -1;
		rc = ENOSPC;
	} else {
		MPASS(fa >= 0 && fa < sc->params.nsched_cls);
		tc = &pi->sched_params->cl_rl[fa];
		MPASS(!(tc->flags & CF_USER));
		MPASS(tc->refcount == 0);

		tc->refcount = 1;
		tc->state = CS_HW_UPDATE_REQUESTED;
		tc->ratemode = FW_SCHED_PARAMS_RATE_ABS;
		tc->rateunit = FW_SCHED_PARAMS_UNIT_BITRATE;
		tc->mode = FW_SCHED_PARAMS_MODE_FLOW;
		tc->maxrate = maxrate;
		tc->pktsize = pktsize;
		tc->burstsize = burstsize;
		*tc_idx = fa;
		update = true;
	}
done:
	mtx_unlock(&sc->tc_lock);
	if (update)
		t4_update_tx_sched(sc);
	return (rc);
}

void
t4_release_cl_rl(struct adapter *sc, int port_id, int tc_idx)
{
	struct tx_cl_rl_params *tc;

	MPASS(port_id >= 0 && port_id < sc->params.nports);
	MPASS(tc_idx >= 0 && tc_idx < sc->params.nsched_cls);

	mtx_lock(&sc->tc_lock);
	tc = &sc->port[port_id]->sched_params->cl_rl[tc_idx];
	MPASS(tc->refcount > 0);
	tc->refcount--;
	mtx_unlock(&sc->tc_lock);
}

int
sysctl_tc(SYSCTL_HANDLER_ARGS)
{
	struct vi_info *vi = arg1;
	struct adapter *sc = vi->adapter;
	struct sge_txq *txq;
	int qidx = arg2, rc, tc_idx;

	MPASS(qidx >= vi->first_txq && qidx < vi->first_txq + vi->ntxq);

	txq = &sc->sge.txq[qidx];
	tc_idx = txq->tc_idx;
	rc = sysctl_handle_int(oidp, &tc_idx, 0, req);
	if (rc != 0 || req->newptr == NULL)
		return (rc);

	if (sc->flags & IS_VF)
		return (EPERM);
	if (!in_range(tc_idx, 0, sc->params.nsched_cls - 1))
		return (EINVAL);

	return (bind_txq_to_traffic_class(sc, txq, tc_idx));
}

int
sysctl_tc_params(SYSCTL_HANDLER_ARGS)
{
	struct adapter *sc = arg1;
	struct tx_cl_rl_params tc;
	struct sbuf *sb;
	int i, rc, port_id, mbps, gbps;

	rc = sysctl_wire_old_buffer(req, 0);
	if (rc != 0)
		return (rc);

	sb = sbuf_new_for_sysctl(NULL, NULL, 4096, req);
	if (sb == NULL)
		return (ENOMEM);

	port_id = arg2 >> 16;
	MPASS(port_id < sc->params.nports);
	MPASS(sc->port[port_id] != NULL);
	i = arg2 & 0xffff;
	MPASS(i < sc->params.nsched_cls);

	mtx_lock(&sc->tc_lock);
	tc = sc->port[port_id]->sched_params->cl_rl[i];
	mtx_unlock(&sc->tc_lock);

	if (tc.state < CS_PARAMS_SET) {
		sbuf_printf(sb, "uninitialized");
		goto done;
	}

	switch (tc.rateunit) {
	case SCHED_CLASS_RATEUNIT_BITS:
		switch (tc.ratemode) {
		case SCHED_CLASS_RATEMODE_REL:
			/* XXX: top speed or actual link speed? */
			gbps = port_top_speed(sc->port[port_id]);
			sbuf_printf(sb, "%u%% of %uGbps", tc.maxrate, gbps);
			break;
		case SCHED_CLASS_RATEMODE_ABS:
			mbps = tc.maxrate / 1000;
			gbps = tc.maxrate / 1000000;
			if (tc.maxrate == gbps * 1000000)
				sbuf_printf(sb, "%uGbps", gbps);
			else if (tc.maxrate == mbps * 1000)
				sbuf_printf(sb, "%uMbps", mbps);
			else
				sbuf_printf(sb, "%uKbps", tc.maxrate);
			break;
		default:
			rc = ENXIO;
			goto done;
		}
		break;
	case SCHED_CLASS_RATEUNIT_PKTS:
		sbuf_printf(sb, "%upps", tc.maxrate);
		break;
	default:
		rc = ENXIO;
		goto done;
	}

	switch (tc.mode) {
	case SCHED_CLASS_MODE_CLASS:
		/* Note that pktsize and burstsize are not used in this mode. */
		sbuf_printf(sb, " aggregate");
		break;
	case SCHED_CLASS_MODE_FLOW:
		sbuf_printf(sb, " per-flow");
		if (tc.pktsize > 0)
			sbuf_printf(sb, " pkt-size %u", tc.pktsize);
		if (tc.burstsize > 0)
			sbuf_printf(sb, " burst-size %u", tc.burstsize);
		break;
	default:
		rc = ENXIO;
		goto done;
	}

done:
	if (rc == 0)
		rc = sbuf_finish(sb);
	sbuf_delete(sb);

	return (rc);
}

#ifdef RATELIMIT
void
t4_init_etid_table(struct adapter *sc)
{
	int i;
	struct tid_info *t;

	if (!is_ethoffload(sc))
		return;

	t = &sc->tids;
	MPASS(t->netids > 0);

	mtx_init(&t->etid_lock, "etid lock", NULL, MTX_DEF);
	t->etid_tab = malloc(sizeof(*t->etid_tab) * t->netids, M_CXGBE,
			M_ZERO | M_WAITOK);
	t->efree = t->etid_tab;
	t->etids_in_use = 0;
	for (i = 1; i < t->netids; i++)
		t->etid_tab[i - 1].next = &t->etid_tab[i];
	t->etid_tab[t->netids - 1].next = NULL;
}

void
t4_free_etid_table(struct adapter *sc)
{
	struct tid_info *t;

	if (!is_ethoffload(sc))
		return;

	t = &sc->tids;
	MPASS(t->netids > 0);

	free(t->etid_tab, M_CXGBE);
	t->etid_tab = NULL;

	if (mtx_initialized(&t->etid_lock))
		mtx_destroy(&t->etid_lock);
}

/* etid services */
static int alloc_etid(struct adapter *, struct cxgbe_rate_tag *);
static void free_etid(struct adapter *, int);

static int
alloc_etid(struct adapter *sc, struct cxgbe_rate_tag *cst)
{
	struct tid_info *t = &sc->tids;
	int etid = -1;

	mtx_lock(&t->etid_lock);
	if (t->efree) {
		union etid_entry *p = t->efree;

		etid = p - t->etid_tab + t->etid_base;
		t->efree = p->next;
		p->cst = cst;
		t->etids_in_use++;
	}
	mtx_unlock(&t->etid_lock);
	return (etid);
}

struct cxgbe_rate_tag *
lookup_etid(struct adapter *sc, int etid)
{
	struct tid_info *t = &sc->tids;

	return (t->etid_tab[etid - t->etid_base].cst);
}

static void
free_etid(struct adapter *sc, int etid)
{
	struct tid_info *t = &sc->tids;
	union etid_entry *p = &t->etid_tab[etid - t->etid_base];

	mtx_lock(&t->etid_lock);
	p->next = t->efree;
	t->efree = p;
	t->etids_in_use--;
	mtx_unlock(&t->etid_lock);
}

static int cxgbe_rate_tag_modify(struct m_snd_tag *,
    union if_snd_tag_modify_params *);
static int cxgbe_rate_tag_query(struct m_snd_tag *,
    union if_snd_tag_query_params *);
static void cxgbe_rate_tag_free(struct m_snd_tag *);

static const struct if_snd_tag_sw cxgbe_rate_tag_sw = {
	.snd_tag_modify = cxgbe_rate_tag_modify,
	.snd_tag_query = cxgbe_rate_tag_query,
	.snd_tag_free = cxgbe_rate_tag_free,
	.type = IF_SND_TAG_TYPE_RATE_LIMIT
};

int
cxgbe_rate_tag_alloc(if_t ifp, union if_snd_tag_alloc_params *params,
    struct m_snd_tag **pt)
{
	int rc, schedcl;
	struct vi_info *vi = if_getsoftc(ifp);
	struct port_info *pi = vi->pi;
	struct adapter *sc = pi->adapter;
	struct cxgbe_rate_tag *cst;

	MPASS(params->hdr.type == IF_SND_TAG_TYPE_RATE_LIMIT);

	rc = t4_reserve_cl_rl_kbps(sc, pi->port_id,
	    (params->rate_limit.max_rate * 8ULL / 1000), &schedcl);
	if (rc != 0)
		return (rc);
	MPASS(schedcl >= 0 && schedcl < sc->params.nsched_cls);

	cst = malloc(sizeof(*cst), M_CXGBE, M_ZERO | M_NOWAIT);
	if (cst == NULL) {
failed:
		t4_release_cl_rl(sc, pi->port_id, schedcl);
		return (ENOMEM);
	}

	cst->etid = alloc_etid(sc, cst);
	if (cst->etid < 0) {
		free(cst, M_CXGBE);
		goto failed;
	}

	mtx_init(&cst->lock, "cst_lock", NULL, MTX_DEF);
	mbufq_init(&cst->pending_tx, INT_MAX);
	mbufq_init(&cst->pending_fwack, INT_MAX);
	m_snd_tag_init(&cst->com, ifp, &cxgbe_rate_tag_sw);
	cst->flags |= EO_FLOWC_PENDING | EO_SND_TAG_REF;
	cst->adapter = sc;
	cst->port_id = pi->port_id;
	cst->schedcl = schedcl;
	cst->max_rate = params->rate_limit.max_rate;
	cst->tx_credits = sc->params.eo_wr_cred;
	cst->tx_total = cst->tx_credits;
	cst->plen = 0;
	cst->ctrl0 = htobe32(V_TXPKT_OPCODE(CPL_TX_PKT_XT) |
	    V_TXPKT_INTF(pi->tx_chan) | V_TXPKT_PF(sc->pf) |
	    V_TXPKT_VF(vi->vin) | V_TXPKT_VF_VLD(vi->vfvld));

	/*
	 * Queues will be selected later when the connection flowid is available.
	 */

	*pt = &cst->com;
	return (0);
}

/*
 * Change in parameters, no change in ifp.
 */
static int
cxgbe_rate_tag_modify(struct m_snd_tag *mst,
    union if_snd_tag_modify_params *params)
{
	int rc, schedcl;
	struct cxgbe_rate_tag *cst = mst_to_crt(mst);
	struct adapter *sc = cst->adapter;

	/* XXX: is schedcl -1 ok here? */
	MPASS(cst->schedcl >= 0 && cst->schedcl < sc->params.nsched_cls);

	mtx_lock(&cst->lock);
	MPASS(cst->flags & EO_SND_TAG_REF);
	rc = t4_reserve_cl_rl_kbps(sc, cst->port_id,
	    (params->rate_limit.max_rate * 8ULL / 1000), &schedcl);
	if (rc != 0)
		return (rc);
	MPASS(schedcl >= 0 && schedcl < sc->params.nsched_cls);
	t4_release_cl_rl(sc, cst->port_id, cst->schedcl);
	cst->schedcl = schedcl;
	cst->max_rate = params->rate_limit.max_rate;
	mtx_unlock(&cst->lock);

	return (0);
}

static int
cxgbe_rate_tag_query(struct m_snd_tag *mst,
    union if_snd_tag_query_params *params)
{
	struct cxgbe_rate_tag *cst = mst_to_crt(mst);

	params->rate_limit.max_rate = cst->max_rate;

#define CST_TO_MST_QLEVEL_SCALE (IF_SND_QUEUE_LEVEL_MAX / cst->tx_total)
	params->rate_limit.queue_level =
		(cst->tx_total - cst->tx_credits) * CST_TO_MST_QLEVEL_SCALE;

	return (0);
}

/*
 * Unlocks cst and frees it.
 */
void
cxgbe_rate_tag_free_locked(struct cxgbe_rate_tag *cst)
{
	struct adapter *sc = cst->adapter;

	mtx_assert(&cst->lock, MA_OWNED);
	MPASS((cst->flags & EO_SND_TAG_REF) == 0);
	MPASS(cst->tx_credits == cst->tx_total);
	MPASS(cst->plen == 0);
	MPASS(mbufq_first(&cst->pending_tx) == NULL);
	MPASS(mbufq_first(&cst->pending_fwack) == NULL);

	if (cst->etid >= 0)
		free_etid(sc, cst->etid);
	if (cst->schedcl != -1)
		t4_release_cl_rl(sc, cst->port_id, cst->schedcl);
	mtx_unlock(&cst->lock);
	mtx_destroy(&cst->lock);
	free(cst, M_CXGBE);
}

static void
cxgbe_rate_tag_free(struct m_snd_tag *mst)
{
	struct cxgbe_rate_tag *cst = mst_to_crt(mst);

	mtx_lock(&cst->lock);

	/* The kernel is done with the snd_tag.  Remove its reference. */
	MPASS(cst->flags & EO_SND_TAG_REF);
	cst->flags &= ~EO_SND_TAG_REF;

	if (cst->ncompl == 0) {
		/*
		 * No fw4_ack in flight.  Free the tag right away if there are
		 * no outstanding credits.  Request the firmware to return all
		 * credits for the etid otherwise.
		 */
		if (cst->tx_credits == cst->tx_total) {
			cxgbe_rate_tag_free_locked(cst);
			return;	/* cst is gone. */
		}
		send_etid_flush_wr(cst);
	}
	mtx_unlock(&cst->lock);
}

void
cxgbe_ratelimit_query(if_t ifp, struct if_ratelimit_query_results *q)
{
	struct vi_info *vi = if_getsoftc(ifp);
	struct adapter *sc = vi->adapter;

	q->rate_table = NULL;
	q->flags = RT_IS_SELECTABLE;
	/*
	 * Absolute max limits from the firmware configuration.  Practical
	 * limits depend on the burstsize, pktsize (if_getmtu(ifp) ultimately) and
	 * the card's cclk.
	 */
	q->max_flows = sc->tids.netids;
	q->number_of_rates = sc->params.nsched_cls;
	q->min_segment_burst = 4; /* matches PKTSCHED_BURST in the firmware. */

#if 1
	if (chip_id(sc) < CHELSIO_T6) {
		/* Based on testing by rrs@ with a T580 at burstsize = 4. */
		MPASS(q->min_segment_burst == 4);
		q->max_flows = min(4000, q->max_flows);
	} else {
		/* XXX: TBD, carried forward from T5 for now. */
		q->max_flows = min(4000, q->max_flows);
	}

	/*
	 * XXX: tcp_ratelimit.c grabs all available rates on link-up before it
	 * even knows whether hw pacing will be used or not.  This prevents
	 * other consumers like SO_MAX_PACING_RATE or those using cxgbetool or
	 * the private ioctls from using any of traffic classes.
	 *
	 * Underreport the number of rates to tcp_ratelimit so that it doesn't
	 * hog all of them.  This can be removed if/when tcp_ratelimit switches
	 * to making its allocations on first-use rather than link-up.  There is
	 * nothing wrong with one particular consumer reserving all the classes
	 * but it should do so only if it'll actually use hw rate limiting.
	 */
	q->number_of_rates /= 4;
#endif
}
#endif