/*
 * Copyright 2012 Red Hat Inc
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * 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.
 *
 * Authors:
 *      Dave Airlie <airlied@redhat.com>
 */
#include <drm/drmP.h>
#include "i915_drv.h"
#include <linux/dma-buf.h>

static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachment,
                                             enum dma_data_direction dir)
{
        struct drm_i915_gem_object *obj = attachment->dmabuf->priv;
        struct sg_table *st;
        struct scatterlist *src, *dst;
        int ret, i;

        ret = i915_mutex_lock_interruptible(obj->base.dev);
        if (ret)
                return ERR_PTR(ret);

        ret = i915_gem_object_get_pages(obj);
        if (ret) {
                st = ERR_PTR(ret);
                goto out;
        }

        /* Copy sg so that we make an independent mapping */
        st = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
        if (st == NULL) {
                st = ERR_PTR(-ENOMEM);
                goto out;
        }

        ret = sg_alloc_table(st, obj->pages->nents, GFP_KERNEL);
        if (ret) {
                kfree(st);
                st = ERR_PTR(ret);
                goto out;
        }

        src = obj->pages->sgl;
        dst = st->sgl;
        for (i = 0; i < obj->pages->nents; i++) {
                sg_set_page(dst, sg_page(src), src->length, 0);
                dst = sg_next(dst);
                src = sg_next(src);
        }

        if (!dma_map_sg(attachment->dev, st->sgl, st->nents, dir)) {
                sg_free_table(st);
                kfree(st);
                st = ERR_PTR(-ENOMEM);
                goto out;
        }

        i915_gem_object_pin_pages(obj);

out:
        mutex_unlock(&obj->base.dev->struct_mutex);
        return st;
}

static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
                                   struct sg_table *sg,
                                   enum dma_data_direction dir)
{
        dma_unmap_sg(attachment->dev, sg->sgl, sg->nents, dir);
        sg_free_table(sg);
        kfree(sg);
}

static void i915_gem_dmabuf_release(struct dma_buf *dma_buf)
{
        struct drm_i915_gem_object *obj = dma_buf->priv;

        if (obj->base.export_dma_buf == dma_buf) {
                /* drop the reference on the export fd holds */
                obj->base.export_dma_buf = NULL;
                drm_gem_object_unreference_unlocked(&obj->base);
        }
}

static void *i915_gem_dmabuf_vmap(struct dma_buf *dma_buf)
{
        struct drm_i915_gem_object *obj = dma_buf->priv;
        struct drm_device *dev = obj->base.dev;
        struct sg_page_iter sg_iter;
        struct page **pages;
        int ret, i;

        ret = i915_mutex_lock_interruptible(dev);
        if (ret)
                return ERR_PTR(ret);

        if (obj->dma_buf_vmapping) {
                obj->vmapping_count++;
                goto out_unlock;
        }

        ret = i915_gem_object_get_pages(obj);
        if (ret)
                goto error;

        ret = -ENOMEM;

        pages = drm_malloc_ab(obj->base.size >> PAGE_SHIFT, sizeof(*pages));
        if (pages == NULL)
                goto error;

        i = 0;
        for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0)
                pages[i++] = sg_page_iter_page(&sg_iter);

        obj->dma_buf_vmapping = vmap(pages, i, 0, PAGE_KERNEL);
        drm_free_large(pages);

        if (!obj->dma_buf_vmapping)
                goto error;

        obj->vmapping_count = 1;
        i915_gem_object_pin_pages(obj);
out_unlock:
        mutex_unlock(&dev->struct_mutex);
        return obj->dma_buf_vmapping;

error:
        mutex_unlock(&dev->struct_mutex);
        return ERR_PTR(ret);
}

static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
{
        struct drm_i915_gem_object *obj = dma_buf->priv;
        struct drm_device *dev = obj->base.dev;
        int ret;

        ret = i915_mutex_lock_interruptible(dev);
        if (ret)
                return;

        if (--obj->vmapping_count == 0) {
                vunmap(obj->dma_buf_vmapping);
                obj->dma_buf_vmapping = NULL;

                i915_gem_object_unpin_pages(obj);
        }
        mutex_unlock(&dev->struct_mutex);
}

static void *i915_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf, unsigned long page_num)
{
        return NULL;
}

static void i915_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
{

}
static void *i915_gem_dmabuf_kmap(struct dma_buf *dma_buf, unsigned long page_num)
{
        return NULL;
}

static void i915_gem_dmabuf_kunmap(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
{

}

static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
{
        return -EINVAL;
}

static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t length, enum dma_data_direction direction)
{
        struct drm_i915_gem_object *obj = dma_buf->priv;
        struct drm_device *dev = obj->base.dev;
        int ret;
        bool write = (direction == DMA_BIDIRECTIONAL || direction == DMA_TO_DEVICE);

        ret = i915_mutex_lock_interruptible(dev);
        if (ret)
                return ret;

        ret = i915_gem_object_set_to_cpu_domain(obj, write);
        mutex_unlock(&dev->struct_mutex);
        return ret;
}

static const struct dma_buf_ops i915_dmabuf_ops =  {
        .map_dma_buf = i915_gem_map_dma_buf,
        .unmap_dma_buf = i915_gem_unmap_dma_buf,
        .release = i915_gem_dmabuf_release,
        .kmap = i915_gem_dmabuf_kmap,
        .kmap_atomic = i915_gem_dmabuf_kmap_atomic,
        .kunmap = i915_gem_dmabuf_kunmap,
        .kunmap_atomic = i915_gem_dmabuf_kunmap_atomic,
        .mmap = i915_gem_dmabuf_mmap,
        .vmap = i915_gem_dmabuf_vmap,
        .vunmap = i915_gem_dmabuf_vunmap,
        .begin_cpu_access = i915_gem_begin_cpu_access,
};

struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
                                      struct drm_gem_object *gem_obj, int flags)
{
        struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);

        return dma_buf_export(obj, &i915_dmabuf_ops, obj->base.size, flags);
}

static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
{
        struct sg_table *sg;

        sg = dma_buf_map_attachment(obj->base.import_attach, DMA_BIDIRECTIONAL);
        if (IS_ERR(sg))
                return PTR_ERR(sg);

        obj->pages = sg;
        obj->has_dma_mapping = true;
        return 0;
}

static void i915_gem_object_put_pages_dmabuf(struct drm_i915_gem_object *obj)
{
        dma_buf_unmap_attachment(obj->base.import_attach,
                                 obj->pages, DMA_BIDIRECTIONAL);
        obj->has_dma_mapping = false;
}

static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
        .get_pages = i915_gem_object_get_pages_dmabuf,
        .put_pages = i915_gem_object_put_pages_dmabuf,
};

struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
                                             struct dma_buf *dma_buf)
{
        struct dma_buf_attachment *attach;
        struct drm_i915_gem_object *obj;
        int ret;

        /* is this one of own objects? */
        if (dma_buf->ops == &i915_dmabuf_ops) {
                obj = dma_buf->priv;
                /* is it from our device? */
                if (obj->base.dev == dev) {
                        /*
                         * Importing dmabuf exported from out own gem increases
                         * refcount on gem itself instead of f_count of dmabuf.
                         */
                        drm_gem_object_reference(&obj->base);
                        return &obj->base;
                }
        }

        /* need to attach */
        attach = dma_buf_attach(dma_buf, dev->dev);
        if (IS_ERR(attach))
                return ERR_CAST(attach);

        get_dma_buf(dma_buf);

        obj = i915_gem_object_alloc(dev);
        if (obj == NULL) {
                ret = -ENOMEM;
                goto fail_detach;
        }

        ret = drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
        if (ret) {
                i915_gem_object_free(obj);
                goto fail_detach;
        }

        i915_gem_object_init(obj, &i915_gem_object_dmabuf_ops);
        obj->base.import_attach = attach;

        return &obj->base;

fail_detach:
        dma_buf_detach(dma_buf, attach);
        dma_buf_put(dma_buf);

        return ERR_PTR(ret);
}