i915_gem_dmabuf.c

Go to the documentation of this file.

/*
 * 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 <[email protected]>
 */
#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), PAGE_SIZE, 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 scatterlist *sg;
    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->pages->nents, sizeof(struct page *));
    if (pages == NULL)
        goto error;

    for_each_sg(obj->pages->sgl, sg, obj->pages->nents, i)
        pages[i] = sg_page(sg);

    obj->dma_buf_vmapping = vmap(pages, obj->pages->nents, 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, 0600);
}

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) {
            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);


    obj = kzalloc(sizeof(*obj), GFP_KERNEL);
    if (obj == NULL) {
        ret = -ENOMEM;
        goto fail_detach;
    }

    ret = drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
    if (ret) {
        kfree(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);
    return ERR_PTR(ret);
}