/*-
 * Copyright (c) 2013-2017, Mellanox Technologies, Ltd.  All rights reserved.
 *
 * 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 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 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 "opt_rss.h"
#include "opt_ratelimit.h"

#include <linux/kernel.h>
#include <linux/module.h>
#include <dev/mlx5/driver.h>
#include <dev/mlx5/mlx5_core/mlx5_core.h>

#ifdef RATELIMIT

/* Finds an entry where we can register the given rate
 * If the rate already exists, return the entry where it is registered,
 * otherwise return the first available entry.
 * If the table is full, return NULL
 */
static struct mlx5_rl_entry *find_rl_entry(struct mlx5_rl_table *table,
                                           u32 rate, u16 burst)
{
        struct mlx5_rl_entry *ret_entry = NULL;
        struct mlx5_rl_entry *entry;
        u16 i;

        for (i = 0; i < table->max_size; i++) {
                entry = table->rl_entry + i;
                if (entry->rate == rate && entry->burst == burst)
                        return entry;
                if (ret_entry == NULL && entry->rate == 0)
                        ret_entry = entry;
        }

        return ret_entry;
}

static int mlx5_set_rate_limit_cmd(struct mlx5_core_dev *dev,
                                   u32 rate, u32 burst, u16 index)
{
        u32 in[MLX5_ST_SZ_DW(set_rate_limit_in)] = {};
        u32 out[MLX5_ST_SZ_DW(set_rate_limit_out)] = {};

        MLX5_SET(set_rate_limit_in, in, opcode, MLX5_CMD_OP_SET_RATE_LIMIT);
        MLX5_SET(set_rate_limit_in, in, rate_limit_index, index);
        MLX5_SET(set_rate_limit_in, in, rate_limit, rate);
        MLX5_SET(set_rate_limit_in, in, burst_upper_bound, burst);
        MLX5_SET(set_rate_limit_in, in, typical_packet_size, 0 /* use MTU */);

        return mlx5_cmd_exec(dev, in, sizeof(in), out, sizeof(out));
}

int mlx5e_query_rate_limit_cmd(struct mlx5_core_dev *dev,
                                   u16 index, u32 *scq_handle)
{
        int err;
        u32 in[MLX5_ST_SZ_DW(query_pp_rate_limit_in)] = {};
        u32 out[MLX5_ST_SZ_DW(query_pp_rate_limit_out)] = {};

        MLX5_SET(query_pp_rate_limit_in, in, opcode, MLX5_CMD_OP_QUERY_RATE_LIMIT);
        MLX5_SET(query_pp_rate_limit_in, in, rate_limit_index, index);

        err = mlx5_cmd_exec(dev, in, sizeof(in), out, sizeof(out));
        if (err)
                return err;

        *scq_handle = MLX5_GET(query_pp_rate_limit_out, out, pp_context.qos_handle);

        return 0;
}

bool mlx5_rl_is_in_range(const struct mlx5_core_dev *dev, u32 rate, u32 burst)
{
        const struct mlx5_rl_table *table = &dev->priv.rl_table;

        return (rate <= table->max_rate && rate >= table->min_rate &&
                burst <= 65535);
}
EXPORT_SYMBOL(mlx5_rl_is_in_range);

int mlx5_rl_add_rate(struct mlx5_core_dev *dev, u32 rate, u32 burst, u16 *index)
{
        struct mlx5_rl_table *table = &dev->priv.rl_table;
        struct mlx5_rl_entry *entry;
        int err = 0;

        mutex_lock(&table->rl_lock);

        if (!rate || !mlx5_rl_is_in_range(dev, rate, burst)) {
                mlx5_core_err(dev, "Invalid rate: %u, should be %u to %u\n",
                              rate, table->min_rate, table->max_rate);
                err = -ERANGE;
                goto out;
        }

        entry = find_rl_entry(table, rate, burst);
        if (!entry) {
                mlx5_core_err(dev, "Max number of %u rates reached\n",
                              table->max_size);
                err = -ENOSPC;
                goto out;
        }
        if (entry->refcount == 0xFFFFFFFFU) {
                /* out of refcounts */
                err = -ENOMEM;
                goto out;
        } else if (entry->refcount != 0) {
                /* rate already configured */
                entry->refcount++;
        } else {
                /* new rate limit */
                err = mlx5_set_rate_limit_cmd(dev, rate, burst, entry->index);
                if (err) {
                        mlx5_core_err(dev, "Failed configuring rate: %u (%d)\n",
                                      rate, err);
                        goto out;
                }
                entry->rate = rate;
                entry->burst = burst;
                entry->refcount = 1;

                if (MLX5_CAP_QOS(dev, qos_remap_pp)) {
                        err = mlx5e_query_rate_limit_cmd(dev, entry->index, &entry->qos_handle);
                        if (err) {
                                mlx5_core_err(dev, "Failed retrieving schedule queue handle for"
                                    "SQ remap: rate: %u error:(%d)\n", rate, err);
                                entry->qos_handle = MLX5_INVALID_QUEUE_HANDLE;
                        }
                } else
                        entry->qos_handle = MLX5_INVALID_QUEUE_HANDLE;
        }
        *index = entry->index;

out:
        mutex_unlock(&table->rl_lock);
        return err;
}
EXPORT_SYMBOL(mlx5_rl_add_rate);

void mlx5_rl_remove_rate(struct mlx5_core_dev *dev, u32 rate, u32 burst)
{
        struct mlx5_rl_table *table = &dev->priv.rl_table;
        struct mlx5_rl_entry *entry = NULL;

        /* 0 is a reserved value for unlimited rate */
        if (rate == 0)
                return;

        mutex_lock(&table->rl_lock);
        entry = find_rl_entry(table, rate, burst);
        if (!entry || !entry->refcount) {
                mlx5_core_warn(dev, "Rate %u is not configured\n", rate);
                goto out;
        }

        entry->refcount--;
        if (!entry->refcount) {
                /* need to remove rate */
                mlx5_set_rate_limit_cmd(dev, 0, 0, entry->index);
                entry->rate = 0;
                entry->burst = 0;
        }

out:
        mutex_unlock(&table->rl_lock);
}
EXPORT_SYMBOL(mlx5_rl_remove_rate);

int mlx5_init_rl_table(struct mlx5_core_dev *dev)
{
        struct mlx5_rl_table *table = &dev->priv.rl_table;
        int i;

        mutex_init(&table->rl_lock);
        if (!MLX5_CAP_GEN(dev, qos) || !MLX5_CAP_QOS(dev, packet_pacing)) {
                table->max_size = 0;
                return 0;
        }

        /* First entry is reserved for unlimited rate */
        table->max_size = MLX5_CAP_QOS(dev, packet_pacing_rate_table_size) - 1;
        table->max_rate = MLX5_CAP_QOS(dev, packet_pacing_max_rate);
        table->min_rate = MLX5_CAP_QOS(dev, packet_pacing_min_rate);

        table->rl_entry = kcalloc(table->max_size, sizeof(struct mlx5_rl_entry),
                                  GFP_KERNEL);
        if (!table->rl_entry)
                return -ENOMEM;

        /* The index represents the index in HW rate limit table
         * Index 0 is reserved for unlimited rate
         */
        for (i = 0; i < table->max_size; i++)
                table->rl_entry[i].index = i + 1;

        return 0;
}

void mlx5_cleanup_rl_table(struct mlx5_core_dev *dev)
{
        struct mlx5_rl_table *table = &dev->priv.rl_table;
        int i;

        /* Clear all configured rates */
        for (i = 0; i < table->max_size; i++)
                if (table->rl_entry[i].rate)
                        mlx5_set_rate_limit_cmd(dev, 0, 0,
                                                table->rl_entry[i].index);

        kfree(dev->priv.rl_table.rl_entry);
}

#endif