[PATCH 2/3] drm/exynos: add dmabuf mmap function

[InKi Dae]

2012/7/10, Cooper Yuan <cooperyuan at gmail.com>:
> implement mmap function of dma_buf_ops.
>

please, add more comments and reveal the source of funding. I think
the source of this patch is omap drm driver.

> Signed-off-by: Cooper Yuan <cooperyuan at gmail.com>
> ---
>  drivers/gpu/drm/exynos/exynos_drm_dmabuf.c |   38
> ++++++++++++++++++++++++++++
>  1 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> index e4eeb0b..913a23e 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> @@ -164,6 +164,43 @@ static void exynos_gem_dmabuf_kunmap(struct
> dma_buf *dma_buf,
>  	/* TODO */
>  }
>
> +static int exynos_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct
> vm_area_struct *vma)
> +{
> +	struct exynos_drm_gem_obj *exynos_gem_obj = dma_buf->priv;
> +	struct drm_device *dev = exynos_gem_obj->base.dev;
> +	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;
> +	int ret = 0;

leave a space.

> +	if (WARN_ON(!exynos_gem_obj->base.filp))
> +		return -EINVAL;
> +
> +	/* Check for valid size. */
> +	if (buf->size < vma->vm_end - vma->vm_start) {
> +		ret = -EINVAL;
> +		goto out_unlock;
> +	}
> +
> +	if (!dev->driver->gem_vm_ops) {
> +		ret = -EINVAL;
> +		goto out_unlock;
> +	}
> +
> +	vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
> +	vma->vm_ops = dev->driver->gem_vm_ops;
> +	vma->vm_private_data = exynos_gem_obj;
> +	vma->vm_page_prot =
> pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
> +

exynos drm driver supports cache attributes, non-cachable or cachable
so the cache attribute should also be considered. please set proper
cache attribute checking current gem object.

> +	/* Take a ref for this mapping of the object, so that the fault
> +	 * handler can dereference the mmap offset's pointer to the object.
> +	 * This reference is cleaned up by the corresponding vm_close
> +	 * (which should happen whether the vma was created by this call, or
> +	 * by a vm_open due to mremap or partial unmap or whatever).
> +	 */
> +	vma->vm_ops->open(vma);
> +
> +out_unlock:
> +	return ret;
> +}
> +
>  static struct dma_buf_ops exynos_dmabuf_ops = {
>  	.map_dma_buf		= exynos_gem_map_dma_buf,
>  	.unmap_dma_buf		= exynos_gem_unmap_dma_buf,
> @@ -172,6 +209,7 @@ static struct dma_buf_ops exynos_dmabuf_ops = {
>  	.kunmap			= exynos_gem_dmabuf_kunmap,
>  	.kunmap_atomic		= exynos_gem_dmabuf_kunmap_atomic,
>  	.release		= exynos_dmabuf_release,
> +	.mmap			= exynos_gem_dmabuf_mmap,
>  };
>
>  struct dma_buf *exynos_dmabuf_prime_export(struct drm_device *drm_dev,
> --
> 1.7.0.4
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