/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2016 Intel Corporation
 */

#include <linux/vmalloc.h>
#include "mock_dmabuf.h"

static struct sg_table *mock_map_dma_buf(struct dma_buf_attachment *attachment,
                                         enum dma_data_direction dir)
{
        struct mock_dmabuf *mock = to_mock(attachment->dmabuf);
        struct sg_table *st;
        struct scatterlist *sg;
        int i, err;

        st = kmalloc(sizeof(*st), GFP_KERNEL);
        if (!st)
                return ERR_PTR(-ENOMEM);

        err = sg_alloc_table(st, mock->npages, GFP_KERNEL);
        if (err)
                goto err_free;

        sg = st->sgl;
        for (i = 0; i < mock->npages; i++) {
                sg_set_page(sg, mock->pages[i], PAGE_SIZE, 0);
                sg = sg_next(sg);
        }

        err = dma_map_sgtable(attachment->dev, st, dir, 0);
        if (err)
                goto err_st;

        return st;

err_st:
        sg_free_table(st);
err_free:
        kfree(st);
        return ERR_PTR(err);
}

static void mock_unmap_dma_buf(struct dma_buf_attachment *attachment,
                               struct sg_table *st,
                               enum dma_data_direction dir)
{
        dma_unmap_sgtable(attachment->dev, st, dir, 0);
        sg_free_table(st);
        kfree(st);
}

static void mock_dmabuf_release(struct dma_buf *dma_buf)
{
        struct mock_dmabuf *mock = to_mock(dma_buf);
        int i;

        for (i = 0; i < mock->npages; i++)
                put_page(mock->pages[i]);

        kfree(mock);
}

static int mock_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map)
{
        struct mock_dmabuf *mock = to_mock(dma_buf);
        void *vaddr;

        vaddr = vm_map_ram(mock->pages, mock->npages, 0);
        if (!vaddr)
                return -ENOMEM;
        iosys_map_set_vaddr(map, vaddr);

        return 0;
}

static void mock_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map)
{
        struct mock_dmabuf *mock = to_mock(dma_buf);

        vm_unmap_ram(map->vaddr, mock->npages);
}

static int mock_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
{
        return -ENODEV;
}

static const struct dma_buf_ops mock_dmabuf_ops =  {
        .map_dma_buf = mock_map_dma_buf,
        .unmap_dma_buf = mock_unmap_dma_buf,
        .release = mock_dmabuf_release,
        .mmap = mock_dmabuf_mmap,
        .vmap = mock_dmabuf_vmap,
        .vunmap = mock_dmabuf_vunmap,
};

static struct dma_buf *mock_dmabuf(int npages)
{
        struct mock_dmabuf *mock;
        DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
        struct dma_buf *dmabuf;
        int i;

        mock = kmalloc(struct_size(mock, pages, npages), GFP_KERNEL);
        if (!mock)
                return ERR_PTR(-ENOMEM);

        mock->npages = npages;
        for (i = 0; i < npages; i++) {
                mock->pages[i] = alloc_page(GFP_KERNEL);
                if (!mock->pages[i])
                        goto err;
        }

        exp_info.ops = &mock_dmabuf_ops;
        exp_info.size = npages * PAGE_SIZE;
        exp_info.flags = O_CLOEXEC;
        exp_info.priv = mock;

        dmabuf = dma_buf_export(&exp_info);
        if (IS_ERR(dmabuf))
                goto err;

        return dmabuf;

err:
        while (i--)
                put_page(mock->pages[i]);
        kfree(mock);
        return ERR_PTR(-ENOMEM);
}