/*-
 * 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/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <dev/mlx5/driver.h>
#include <dev/mlx5/mlx5_core/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.
 */

static void
mlx5_buf_load_mem_cb(void *arg, bus_dma_segment_t *segs, int nseg, int error)
{
        struct mlx5_buf *buf;
        uint8_t owned;
        int x;

        buf = (struct mlx5_buf *)arg;
        owned = MLX5_DMA_OWNED(buf->dev);

        if (!owned)
                MLX5_DMA_LOCK(buf->dev);

        if (error == 0) {
                for (x = 0; x != nseg; x++) {
                        buf->page_list[x] = segs[x].ds_addr;
                        KASSERT(segs[x].ds_len == PAGE_SIZE, ("Invalid segment size"));
                }
                buf->load_done = MLX5_LOAD_ST_SUCCESS;
        } else {
                buf->load_done = MLX5_LOAD_ST_FAILURE;
        }
        MLX5_DMA_DONE(buf->dev);

        if (!owned)
                MLX5_DMA_UNLOCK(buf->dev);
}

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

        buf->npages = howmany(size, PAGE_SIZE);
        buf->page_shift = PAGE_SHIFT;
        buf->load_done = MLX5_LOAD_ST_NONE;
        buf->dev = dev;
        buf->page_list = kcalloc(buf->npages, sizeof(*buf->page_list),
            GFP_KERNEL);

        err = -bus_dma_tag_create(
            bus_get_dma_tag(dev->pdev->dev.bsddev),
            PAGE_SIZE,          /* alignment */
            0,                  /* no boundary */
            BUS_SPACE_MAXADDR,  /* lowaddr */
            BUS_SPACE_MAXADDR,  /* highaddr */
            NULL, NULL,         /* filter, filterarg */
            PAGE_SIZE * buf->npages,    /* maxsize */
            buf->npages,        /* nsegments */
            PAGE_SIZE,          /* maxsegsize */
            0,                  /* flags */
            NULL, NULL,         /* lockfunc, lockfuncarg */
            &buf->dma_tag);

        if (err != 0)
                goto err_dma_tag;

        /* allocate memory */
        err = -bus_dmamem_alloc(buf->dma_tag, &buf->direct.buf,
            BUS_DMA_WAITOK | BUS_DMA_COHERENT, &buf->dma_map);
        if (err != 0)
                goto err_dma_alloc;

        /* load memory into DMA */
        MLX5_DMA_LOCK(dev);
        err = bus_dmamap_load(
            buf->dma_tag, buf->dma_map, buf->direct.buf,
            PAGE_SIZE * buf->npages, &mlx5_buf_load_mem_cb,
            buf, BUS_DMA_WAITOK | BUS_DMA_COHERENT);

        while (buf->load_done == MLX5_LOAD_ST_NONE)
                MLX5_DMA_WAIT(dev);
        MLX5_DMA_UNLOCK(dev);

        /* check for error */
        if (buf->load_done != MLX5_LOAD_ST_SUCCESS) {
                err = -ENOMEM;
                goto err_dma_load;
        }

        /* clean memory */
        memset(buf->direct.buf, 0, PAGE_SIZE * buf->npages);

        /* flush memory to RAM */
        bus_dmamap_sync(buf->dev->cmd.dma_tag, buf->dma_map, BUS_DMASYNC_PREWRITE);
        return (0);

err_dma_load:
        bus_dmamem_free(buf->dma_tag, buf->direct.buf, buf->dma_map);
err_dma_alloc:
        bus_dma_tag_destroy(buf->dma_tag);
err_dma_tag:
        kfree(buf->page_list);
        return (err);
}

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

        bus_dmamap_unload(buf->dma_tag, buf->dma_map);
        bus_dmamem_free(buf->dma_tag, buf->direct.buf, buf->dma_map);
        bus_dma_tag_destroy(buf->dma_tag);
        kfree(buf->page_list);
}
EXPORT_SYMBOL_GPL(mlx5_buf_free);

static struct mlx5_db_pgdir *mlx5_alloc_db_pgdir(struct mlx5_core_dev *dev)
{
        struct mlx5_db_pgdir *pgdir;

        pgdir = kzalloc(sizeof(*pgdir), GFP_KERNEL);

        bitmap_fill(pgdir->bitmap, MLX5_DB_PER_PAGE);

        pgdir->fw_page = mlx5_fwp_alloc(dev, GFP_KERNEL, 1);
        if (pgdir->fw_page != NULL) {
                pgdir->db_page = pgdir->fw_page->virt_addr;
                pgdir->db_dma = pgdir->fw_page->dma_addr;

                /* clean allocated memory */
                memset(pgdir->db_page, 0, MLX5_ADAPTER_PAGE_SIZE);

                /* flush memory to RAM */
                mlx5_fwp_flush(pgdir->fw_page);
        }
        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;

        db->db[0] = 0;
        db->db[1] = 0;

        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);
        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)) {
                mlx5_fwp_free(db->u.pgdir->fw_page);
                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)
{
        int i;

        for (i = 0; i != buf->npages; i++)
                pas[i] = cpu_to_be64(buf->page_list[i]);
}
EXPORT_SYMBOL_GPL(mlx5_fill_page_array);