/*
 * This file is part of the Chelsio T4 Ethernet driver for Linux.
 *
 * Copyright (c) 2016 Chelsio Communications, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - 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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/module.h>
#include <linux/netdevice.h>

#include "cxgb4.h"
#include "sched.h"

/* Spinlock must be held by caller */
static int t4_sched_class_fw_cmd(struct port_info *pi,
				 struct ch_sched_params *p,
				 enum sched_fw_ops op)
{
	struct adapter *adap = pi->adapter;
	struct sched_table *s = pi->sched_tbl;
	struct sched_class *e;
	int err = 0;

	e = &s->tab[p->u.params.class];
	switch (op) {
	case SCHED_FW_OP_ADD:
		err = t4_sched_params(adap, p->type,
				      p->u.params.level, p->u.params.mode,
				      p->u.params.rateunit,
				      p->u.params.ratemode,
				      p->u.params.channel, e->idx,
				      p->u.params.minrate, p->u.params.maxrate,
				      p->u.params.weight, p->u.params.pktsize);
		break;
	default:
		err = -ENOTSUPP;
		break;
	}

	return err;
}

/* Spinlock must be held by caller */
static int t4_sched_bind_unbind_op(struct port_info *pi, void *arg,
				   enum sched_bind_type type, bool bind)
{
	struct adapter *adap = pi->adapter;
	u32 fw_mnem, fw_class, fw_param;
	unsigned int pf = adap->pf;
	unsigned int vf = 0;
	int err = 0;

	switch (type) {
	case SCHED_QUEUE: {
		struct sched_queue_entry *qe;

		qe = (struct sched_queue_entry *)arg;

		/* Create a template for the FW_PARAMS_CMD mnemonic and
		 * value (TX Scheduling Class in this case).
		 */
		fw_mnem = (FW_PARAMS_MNEM_V(FW_PARAMS_MNEM_DMAQ) |
			   FW_PARAMS_PARAM_X_V(
				   FW_PARAMS_PARAM_DMAQ_EQ_SCHEDCLASS_ETH));
		fw_class = bind ? qe->param.class : FW_SCHED_CLS_NONE;
		fw_param = (fw_mnem | FW_PARAMS_PARAM_YZ_V(qe->cntxt_id));

		pf = adap->pf;
		vf = 0;
		break;
	}
	default:
		err = -ENOTSUPP;
		goto out;
	}

	err = t4_set_params(adap, adap->mbox, pf, vf, 1, &fw_param, &fw_class);

out:
	return err;
}

static struct sched_class *t4_sched_queue_lookup(struct port_info *pi,
						 const unsigned int qid,
						 int *index)
{
	struct sched_table *s = pi->sched_tbl;
	struct sched_class *e, *end;
	struct sched_class *found = NULL;
	int i;

	/* Look for a class with matching bound queue parameters */
	end = &s->tab[s->sched_size];
	for (e = &s->tab[0]; e != end; ++e) {
		struct sched_queue_entry *qe;

		i = 0;
		if (e->state == SCHED_STATE_UNUSED)
			continue;

		list_for_each_entry(qe, &e->queue_list, list) {
			if (qe->cntxt_id == qid) {
				found = e;
				if (index)
					*index = i;
				break;
			}
			i++;
		}

		if (found)
			break;
	}

	return found;
}

static int t4_sched_queue_unbind(struct port_info *pi, struct ch_sched_queue *p)
{
	struct adapter *adap = pi->adapter;
	struct sched_class *e;
	struct sched_queue_entry *qe = NULL;
	struct sge_eth_txq *txq;
	unsigned int qid;
	int index = -1;
	int err = 0;

	if (p->queue < 0 || p->queue >= pi->nqsets)
		return -ERANGE;

	txq = &adap->sge.ethtxq[pi->first_qset + p->queue];
	qid = txq->q.cntxt_id;

	/* Find the existing class that the queue is bound to */
	e = t4_sched_queue_lookup(pi, qid, &index);
	if (e && index >= 0) {
		int i = 0;

		spin_lock(&e->lock);
		list_for_each_entry(qe, &e->queue_list, list) {
			if (i == index)
				break;
			i++;
		}
		err = t4_sched_bind_unbind_op(pi, (void *)qe, SCHED_QUEUE,
					      false);
		if (err) {
			spin_unlock(&e->lock);
			goto out;
		}

		list_del(&qe->list);
		kvfree(qe);
		if (atomic_dec_and_test(&e->refcnt)) {
			e->state = SCHED_STATE_UNUSED;
			memset(&e->info, 0, sizeof(e->info));
		}
		spin_unlock(&e->lock);
	}
out:
	return err;
}

static int t4_sched_queue_bind(struct port_info *pi, struct ch_sched_queue *p)
{
	struct adapter *adap = pi->adapter;
	struct sched_table *s = pi->sched_tbl;
	struct sched_class *e;
	struct sched_queue_entry *qe = NULL;
	struct sge_eth_txq *txq;
	unsigned int qid;
	int err = 0;

	if (p->queue < 0 || p->queue >= pi->nqsets)
		return -ERANGE;

	qe = kvzalloc(sizeof(struct sched_queue_entry), GFP_KERNEL);
	if (!qe)
		return -ENOMEM;

	txq = &adap->sge.ethtxq[pi->first_qset + p->queue];
	qid = txq->q.cntxt_id;

	/* Unbind queue from any existing class */
	err = t4_sched_queue_unbind(pi, p);
	if (err) {
		kvfree(qe);
		goto out;
	}

	/* Bind queue to specified class */
	memset(qe, 0, sizeof(*qe));
	qe->cntxt_id = qid;
	memcpy(&qe->param, p, sizeof(qe->param));

	e = &s->tab[qe->param.class];
	spin_lock(&e->lock);
	err = t4_sched_bind_unbind_op(pi, (void *)qe, SCHED_QUEUE, true);
	if (err) {
		kvfree(qe);
		spin_unlock(&e->lock);
		goto out;
	}

	list_add_tail(&qe->list, &e->queue_list);
	atomic_inc(&e->refcnt);
	spin_unlock(&e->lock);
out:
	return err;
}

static void t4_sched_class_unbind_all(struct port_info *pi,
				      struct sched_class *e,
				      enum sched_bind_type type)
{
	if (!e)
		return;

	switch (type) {
	case SCHED_QUEUE: {
		struct sched_queue_entry *qe;

		list_for_each_entry(qe, &e->queue_list, list)
			t4_sched_queue_unbind(pi, &qe->param);
		break;
	}
	default:
		break;
	}
}

static int t4_sched_class_bind_unbind_op(struct port_info *pi, void *arg,
					 enum sched_bind_type type, bool bind)
{
	int err = 0;

	if (!arg)
		return -EINVAL;

	switch (type) {
	case SCHED_QUEUE: {
		struct ch_sched_queue *qe = (struct ch_sched_queue *)arg;

		if (bind)
			err = t4_sched_queue_bind(pi, qe);
		else
			err = t4_sched_queue_unbind(pi, qe);
		break;
	}
	default:
		err = -ENOTSUPP;
		break;
	}

	return err;
}

/**
 * cxgb4_sched_class_bind - Bind an entity to a scheduling class
 * @dev: net_device pointer
 * @arg: Entity opaque data
 * @type: Entity type (Queue)
 *
 * Binds an entity (queue) to a scheduling class.  If the entity
 * is bound to another class, it will be unbound from the other class
 * and bound to the class specified in @arg.
 */
int cxgb4_sched_class_bind(struct net_device *dev, void *arg,
			   enum sched_bind_type type)
{
	struct port_info *pi = netdev2pinfo(dev);
	struct sched_table *s;
	int err = 0;
	u8 class_id;

	if (!can_sched(dev))
		return -ENOTSUPP;

	if (!arg)
		return -EINVAL;

	switch (type) {
	case SCHED_QUEUE: {
		struct ch_sched_queue *qe = (struct ch_sched_queue *)arg;

		class_id = qe->class;
		break;
	}
	default:
		return -ENOTSUPP;
	}

	if (!valid_class_id(dev, class_id))
		return -EINVAL;

	if (class_id == SCHED_CLS_NONE)
		return -ENOTSUPP;

	s = pi->sched_tbl;
	write_lock(&s->rw_lock);
	err = t4_sched_class_bind_unbind_op(pi, arg, type, true);
	write_unlock(&s->rw_lock);

	return err;
}

/**
 * cxgb4_sched_class_unbind - Unbind an entity from a scheduling class
 * @dev: net_device pointer
 * @arg: Entity opaque data
 * @type: Entity type (Queue)
 *
 * Unbinds an entity (queue) from a scheduling class.
 */
int cxgb4_sched_class_unbind(struct net_device *dev, void *arg,
			     enum sched_bind_type type)
{
	struct port_info *pi = netdev2pinfo(dev);
	struct sched_table *s;
	int err = 0;
	u8 class_id;

	if (!can_sched(dev))
		return -ENOTSUPP;

	if (!arg)
		return -EINVAL;

	switch (type) {
	case SCHED_QUEUE: {
		struct ch_sched_queue *qe = (struct ch_sched_queue *)arg;

		class_id = qe->class;
		break;
	}
	default:
		return -ENOTSUPP;
	}

	if (!valid_class_id(dev, class_id))
		return -EINVAL;

	s = pi->sched_tbl;
	write_lock(&s->rw_lock);
	err = t4_sched_class_bind_unbind_op(pi, arg, type, false);
	write_unlock(&s->rw_lock);

	return err;
}

/* If @p is NULL, fetch any available unused class */
static struct sched_class *t4_sched_class_lookup(struct port_info *pi,
						const struct ch_sched_params *p)
{
	struct sched_table *s = pi->sched_tbl;
	struct sched_class *e, *end;
	struct sched_class *found = NULL;

	if (!p) {
		/* Get any available unused class */
		end = &s->tab[s->sched_size];
		for (e = &s->tab[0]; e != end; ++e) {
			if (e->state == SCHED_STATE_UNUSED) {
				found = e;
				break;
			}
		}
	} else {
		/* Look for a class with matching scheduling parameters */
		struct ch_sched_params info;
		struct ch_sched_params tp;

		memcpy(&tp, p, sizeof(tp));
		/* Don't try to match class parameter */
		tp.u.params.class = SCHED_CLS_NONE;

		end = &s->tab[s->sched_size];
		for (e = &s->tab[0]; e != end; ++e) {
			if (e->state == SCHED_STATE_UNUSED)
				continue;

			memcpy(&info, &e->info, sizeof(info));
			/* Don't try to match class parameter */
			info.u.params.class = SCHED_CLS_NONE;

			if ((info.type == tp.type) &&
			    (!memcmp(&info.u.params, &tp.u.params,
				     sizeof(info.u.params)))) {
				found = e;
				break;
			}
		}
	}

	return found;
}

static struct sched_class *t4_sched_class_alloc(struct port_info *pi,
						struct ch_sched_params *p)
{
	struct sched_table *s = pi->sched_tbl;
	struct sched_class *e;
	u8 class_id;
	int err;

	if (!p)
		return NULL;

	class_id = p->u.params.class;

	/* Only accept search for existing class with matching params
	 * or allocation of new class with specified params
	 */
	if (class_id != SCHED_CLS_NONE)
		return NULL;

	write_lock(&s->rw_lock);
	/* See if there's an exisiting class with same
	 * requested sched params
	 */
	e = t4_sched_class_lookup(pi, p);
	if (!e) {
		struct ch_sched_params np;

		/* Fetch any available unused class */
		e = t4_sched_class_lookup(pi, NULL);
		if (!e)
			goto out;

		memcpy(&np, p, sizeof(np));
		np.u.params.class = e->idx;

		spin_lock(&e->lock);
		/* New class */
		err = t4_sched_class_fw_cmd(pi, &np, SCHED_FW_OP_ADD);
		if (err) {
			spin_unlock(&e->lock);
			e = NULL;
			goto out;
		}
		memcpy(&e->info, &np, sizeof(e->info));
		atomic_set(&e->refcnt, 0);
		e->state = SCHED_STATE_ACTIVE;
		spin_unlock(&e->lock);
	}

out:
	write_unlock(&s->rw_lock);
	return e;
}

/**
 * cxgb4_sched_class_alloc - allocate a scheduling class
 * @dev: net_device pointer
 * @p: new scheduling class to create.
 *
 * Returns pointer to the scheduling class created.  If @p is NULL, then
 * it allocates and returns any available unused scheduling class. If a
 * scheduling class with matching @p is found, then the matching class is
 * returned.
 */
struct sched_class *cxgb4_sched_class_alloc(struct net_device *dev,
					    struct ch_sched_params *p)
{
	struct port_info *pi = netdev2pinfo(dev);
	u8 class_id;

	if (!can_sched(dev))
		return NULL;

	class_id = p->u.params.class;
	if (!valid_class_id(dev, class_id))
		return NULL;

	return t4_sched_class_alloc(pi, p);
}

static void t4_sched_class_free(struct port_info *pi, struct sched_class *e)
{
	t4_sched_class_unbind_all(pi, e, SCHED_QUEUE);
}

struct sched_table *t4_init_sched(unsigned int sched_size)
{
	struct sched_table *s;
	unsigned int i;

	s = kvzalloc(sizeof(*s) + sched_size * sizeof(struct sched_class), GFP_KERNEL);
	if (!s)
		return NULL;

	s->sched_size = sched_size;
	rwlock_init(&s->rw_lock);

	for (i = 0; i < s->sched_size; i++) {
		memset(&s->tab[i], 0, sizeof(struct sched_class));
		s->tab[i].idx = i;
		s->tab[i].state = SCHED_STATE_UNUSED;
		INIT_LIST_HEAD(&s->tab[i].queue_list);
		spin_lock_init(&s->tab[i].lock);
		atomic_set(&s->tab[i].refcnt, 0);
	}
	return s;
}

void t4_cleanup_sched(struct adapter *adap)
{
	struct sched_table *s;
	unsigned int j, i;

	for_each_port(adap, j) {
		struct port_info *pi = netdev2pinfo(adap->port[j]);

		s = pi->sched_tbl;
		if (!s)
			continue;

		for (i = 0; i < s->sched_size; i++) {
			struct sched_class *e;

			write_lock(&s->rw_lock);
			e = &s->tab[i];
			if (e->state == SCHED_STATE_ACTIVE)
				t4_sched_class_free(pi, e);
			write_unlock(&s->rw_lock);
		}
		kvfree(s);
	}
}