/*
 * drivers/net/ethernet/mellanox/mlxsw/spectrum_cnt.c
 * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
 * Copyright (c) 2017 Arkadi Sharshevsky <arkadis@mellanox.com>
 *
 * 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.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 <linux/kernel.h>
#include <linux/bitops.h>

#include "spectrum_cnt.h"

#define MLXSW_SP_COUNTER_POOL_BANK_SIZE 4096

struct mlxsw_sp_counter_sub_pool {
	unsigned int base_index;
	unsigned int size;
	unsigned int entry_size;
	unsigned int bank_count;
};

struct mlxsw_sp_counter_pool {
	unsigned int pool_size;
	unsigned long *usage; /* Usage bitmap */
	struct mlxsw_sp_counter_sub_pool *sub_pools;
};

static struct mlxsw_sp_counter_sub_pool mlxsw_sp_counter_sub_pools[] = {
	[MLXSW_SP_COUNTER_SUB_POOL_FLOW] = {
		.bank_count = 6,
	},
	[MLXSW_SP_COUNTER_SUB_POOL_RIF] = {
		.bank_count = 2,
	}
};

static int mlxsw_sp_counter_pool_validate(struct mlxsw_sp *mlxsw_sp)
{
	unsigned int total_bank_config = 0;
	unsigned int pool_size;
	int i;

	pool_size = MLXSW_CORE_RES_GET(mlxsw_sp->core, COUNTER_POOL_SIZE);
	/* Check config is valid, no bank over subscription */
	for (i = 0; i < ARRAY_SIZE(mlxsw_sp_counter_sub_pools); i++)
		total_bank_config += mlxsw_sp_counter_sub_pools[i].bank_count;
	if (total_bank_config > pool_size / MLXSW_SP_COUNTER_POOL_BANK_SIZE + 1)
		return -EINVAL;
	return 0;
}

static int mlxsw_sp_counter_sub_pools_prepare(struct mlxsw_sp *mlxsw_sp)
{
	struct mlxsw_sp_counter_sub_pool *sub_pool;

	/* Prepare generic flow pool*/
	sub_pool = &mlxsw_sp_counter_sub_pools[MLXSW_SP_COUNTER_SUB_POOL_FLOW];
	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, COUNTER_SIZE_PACKETS_BYTES))
		return -EIO;
	sub_pool->entry_size = MLXSW_CORE_RES_GET(mlxsw_sp->core,
						  COUNTER_SIZE_PACKETS_BYTES);
	/* Prepare erif pool*/
	sub_pool = &mlxsw_sp_counter_sub_pools[MLXSW_SP_COUNTER_SUB_POOL_RIF];
	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, COUNTER_SIZE_ROUTER_BASIC))
		return -EIO;
	sub_pool->entry_size = MLXSW_CORE_RES_GET(mlxsw_sp->core,
						  COUNTER_SIZE_ROUTER_BASIC);
	return 0;
}

int mlxsw_sp_counter_pool_init(struct mlxsw_sp *mlxsw_sp)
{
	struct mlxsw_sp_counter_sub_pool *sub_pool;
	struct mlxsw_sp_counter_pool *pool;
	unsigned int base_index;
	unsigned int map_size;
	int i;
	int err;

	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, COUNTER_POOL_SIZE))
		return -EIO;

	err = mlxsw_sp_counter_pool_validate(mlxsw_sp);
	if (err)
		return err;

	err = mlxsw_sp_counter_sub_pools_prepare(mlxsw_sp);
	if (err)
		return err;

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

	pool->pool_size = MLXSW_CORE_RES_GET(mlxsw_sp->core, COUNTER_POOL_SIZE);
	map_size = BITS_TO_LONGS(pool->pool_size) * sizeof(unsigned long);

	pool->usage = kzalloc(map_size, GFP_KERNEL);
	if (!pool->usage) {
		err = -ENOMEM;
		goto err_usage_alloc;
	}

	pool->sub_pools = mlxsw_sp_counter_sub_pools;
	/* Allocation is based on bank count which should be
	 * specified for each sub pool statically.
	 */
	base_index = 0;
	for (i = 0; i < ARRAY_SIZE(mlxsw_sp_counter_sub_pools); i++) {
		sub_pool = &pool->sub_pools[i];
		sub_pool->size = sub_pool->bank_count *
				 MLXSW_SP_COUNTER_POOL_BANK_SIZE;
		sub_pool->base_index = base_index;
		base_index += sub_pool->size;
		/* The last bank can't be fully used */
		if (sub_pool->base_index + sub_pool->size > pool->pool_size)
			sub_pool->size = pool->pool_size - sub_pool->base_index;
	}

	mlxsw_sp->counter_pool = pool;
	return 0;

err_usage_alloc:
	kfree(pool);
	return err;
}

void mlxsw_sp_counter_pool_fini(struct mlxsw_sp *mlxsw_sp)
{
	struct mlxsw_sp_counter_pool *pool = mlxsw_sp->counter_pool;

	WARN_ON(find_first_bit(pool->usage, pool->pool_size) !=
			       pool->pool_size);
	kfree(pool->usage);
	kfree(pool);
}

int mlxsw_sp_counter_alloc(struct mlxsw_sp *mlxsw_sp,
			   enum mlxsw_sp_counter_sub_pool_id sub_pool_id,
			   unsigned int *p_counter_index)
{
	struct mlxsw_sp_counter_pool *pool = mlxsw_sp->counter_pool;
	struct mlxsw_sp_counter_sub_pool *sub_pool;
	unsigned int entry_index;
	unsigned int stop_index;
	int i;

	sub_pool = &mlxsw_sp_counter_sub_pools[sub_pool_id];
	stop_index = sub_pool->base_index + sub_pool->size;
	entry_index = sub_pool->base_index;

	entry_index = find_next_zero_bit(pool->usage, stop_index, entry_index);
	if (entry_index == stop_index)
		return -ENOBUFS;
	/* The sub-pools can contain non-integer number of entries
	 * so we must check for overflow
	 */
	if (entry_index + sub_pool->entry_size > stop_index)
		return -ENOBUFS;
	for (i = 0; i < sub_pool->entry_size; i++)
		__set_bit(entry_index + i, pool->usage);

	*p_counter_index = entry_index;
	return 0;
}

void mlxsw_sp_counter_free(struct mlxsw_sp *mlxsw_sp,
			   enum mlxsw_sp_counter_sub_pool_id sub_pool_id,
			   unsigned int counter_index)
{
	struct mlxsw_sp_counter_pool *pool = mlxsw_sp->counter_pool;
	struct mlxsw_sp_counter_sub_pool *sub_pool;
	int i;

	if (WARN_ON(counter_index >= pool->pool_size))
		return;
	sub_pool = &mlxsw_sp_counter_sub_pools[sub_pool_id];
	for (i = 0; i < sub_pool->entry_size; i++)
		__clear_bit(counter_index + i, pool->usage);
}