/*
 * Copyright (c) 2013, Mellanox Technologies 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/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/bitmap.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <linux/mlx5/driver.h>

#include "mlx5_core.h"

/* Handling for queue buffers -- we allocate a bunch of memory and
 * register it in a memory region at HCA virtual address 0.  If the
 * requested size is > max_direct, we split the allocation into
 * multiple pages, so we don't require too much contiguous memory.
 */

int mlx5_buf_alloc(struct mlx5_core_dev *dev, int size, int max_direct,
                   struct mlx5_buf *buf)
{
        dma_addr_t t;

        buf->size = size;
        if (size <= max_direct) {
                buf->nbufs        = 1;
                buf->npages       = 1;
                buf->page_shift   = (u8)get_order(size) + PAGE_SHIFT;
                buf->direct.buf   = dma_zalloc_coherent(&dev->pdev->dev,
                                                        size, &t, GFP_KERNEL);
                if (!buf->direct.buf)
                        return -ENOMEM;

                buf->direct.map = t;

                while (t & ((1 << buf->page_shift) - 1)) {
                        --buf->page_shift;
                        buf->npages *= 2;
                }
        } else {
                int i;

                buf->direct.buf  = NULL;
                buf->nbufs       = (size + PAGE_SIZE - 1) / PAGE_SIZE;
                buf->npages      = buf->nbufs;
                buf->page_shift  = PAGE_SHIFT;
                buf->page_list   = kcalloc(buf->nbufs, sizeof(*buf->page_list),
                                           GFP_KERNEL);
                if (!buf->page_list)
                        return -ENOMEM;

                for (i = 0; i < buf->nbufs; i++) {
                        buf->page_list[i].buf =
                                dma_zalloc_coherent(&dev->pdev->dev, PAGE_SIZE,
                                                    &t, GFP_KERNEL);
                        if (!buf->page_list[i].buf)
                                goto err_free;

                        buf->page_list[i].map = t;
                }

                if (BITS_PER_LONG == 64) {
                        struct page **pages;
                        pages = kmalloc(sizeof(*pages) * buf->nbufs, GFP_KERNEL);
                        if (!pages)
                                goto err_free;
                        for (i = 0; i < buf->nbufs; i++)
                                pages[i] = virt_to_page(buf->page_list[i].buf);
                        buf->direct.buf = vmap(pages, buf->nbufs, VM_MAP, PAGE_KERNEL);
                        kfree(pages);
                        if (!buf->direct.buf)
                                goto err_free;
                }
        }

        return 0;

err_free:
        mlx5_buf_free(dev, buf);

        return -ENOMEM;
}
EXPORT_SYMBOL_GPL(mlx5_buf_alloc);

void mlx5_buf_free(struct mlx5_core_dev *dev, struct mlx5_buf *buf)
{
        int i;

        if (buf->nbufs == 1)
                dma_free_coherent(&dev->pdev->dev, buf->size, buf->direct.buf,
                                  buf->direct.map);
        else {
                if (BITS_PER_LONG == 64)
                        vunmap(buf->direct.buf);

                for (i = 0; i < buf->nbufs; i++)
                        if (buf->page_list[i].buf)
                                dma_free_coherent(&dev->pdev->dev, PAGE_SIZE,
                                                  buf->page_list[i].buf,
                                                  buf->page_list[i].map);
                kfree(buf->page_list);
        }
}
EXPORT_SYMBOL_GPL(mlx5_buf_free);

static struct mlx5_db_pgdir *mlx5_alloc_db_pgdir(struct device *dma_device)
{
        struct mlx5_db_pgdir *pgdir;

        pgdir = kzalloc(sizeof(*pgdir), GFP_KERNEL);
        if (!pgdir)
                return NULL;

        bitmap_fill(pgdir->bitmap, MLX5_DB_PER_PAGE);
        pgdir->db_page = dma_alloc_coherent(dma_device, PAGE_SIZE,
                                            &pgdir->db_dma, GFP_KERNEL);
        if (!pgdir->db_page) {
                kfree(pgdir);
                return NULL;
        }

        return pgdir;
}

static int mlx5_alloc_db_from_pgdir(struct mlx5_db_pgdir *pgdir,
                                    struct mlx5_db *db)
{
        int offset;
        int i;

        i = find_first_bit(pgdir->bitmap, MLX5_DB_PER_PAGE);
        if (i >= MLX5_DB_PER_PAGE)
                return -ENOMEM;

        __clear_bit(i, pgdir->bitmap);

        db->u.pgdir = pgdir;
        db->index   = i;
        offset = db->index * L1_CACHE_BYTES;
        db->db      = pgdir->db_page + offset / sizeof(*pgdir->db_page);
        db->dma     = pgdir->db_dma  + offset;

        return 0;
}

int mlx5_db_alloc(struct mlx5_core_dev *dev, struct mlx5_db *db)
{
        struct mlx5_db_pgdir *pgdir;
        int ret = 0;

        mutex_lock(&dev->priv.pgdir_mutex);

        list_for_each_entry(pgdir, &dev->priv.pgdir_list, list)
                if (!mlx5_alloc_db_from_pgdir(pgdir, db))
                        goto out;

        pgdir = mlx5_alloc_db_pgdir(&(dev->pdev->dev));
        if (!pgdir) {
                ret = -ENOMEM;
                goto out;
        }

        list_add(&pgdir->list, &dev->priv.pgdir_list);

        /* This should never fail -- we just allocated an empty page: */
        WARN_ON(mlx5_alloc_db_from_pgdir(pgdir, db));

out:
        mutex_unlock(&dev->priv.pgdir_mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(mlx5_db_alloc);

void mlx5_db_free(struct mlx5_core_dev *dev, struct mlx5_db *db)
{
        mutex_lock(&dev->priv.pgdir_mutex);

        __set_bit(db->index, db->u.pgdir->bitmap);

        if (bitmap_full(db->u.pgdir->bitmap, MLX5_DB_PER_PAGE)) {
                dma_free_coherent(&(dev->pdev->dev), PAGE_SIZE,
                                  db->u.pgdir->db_page, db->u.pgdir->db_dma);
                list_del(&db->u.pgdir->list);
                kfree(db->u.pgdir);
        }

        mutex_unlock(&dev->priv.pgdir_mutex);
}
EXPORT_SYMBOL_GPL(mlx5_db_free);


void mlx5_fill_page_array(struct mlx5_buf *buf, __be64 *pas)
{
        u64 addr;
        int i;

        for (i = 0; i < buf->npages; i++) {
                if (buf->nbufs == 1)
                        addr = buf->direct.map + (i << buf->page_shift);
                else
                        addr = buf->page_list[i].map;

                pas[i] = cpu_to_be64(addr);
        }
}
EXPORT_SYMBOL_GPL(mlx5_fill_page_array);