drm/amd/amdgpu: Partial revert of iova debugfs

				   size_t size, loff_t *pos)

{

	struct amdgpu_device *adev = file_inode(f)->i_private;

	ssize_t result, n;

	int r;

	uint64_t phys;

	void *ptr;

	struct iommu_domain *dom;

	dom = iommu_get_domain_for_dev(adev->dev);

	if (!dom)

		return -EFAULT;

	result = 0;

	while (size) {

		// get physical address and map

		phys = iommu_iova_to_phys(dom, *pos);

		// copy upto one page

		if (size > PAGE_SIZE)

			n = PAGE_SIZE;

		else

			n = size;

		// to end of the page

		if (((*pos & (PAGE_SIZE - 1)) + n) >= PAGE_SIZE)

			n = PAGE_SIZE - (*pos & (PAGE_SIZE - 1));

		ptr = kmap(pfn_to_page(PFN_DOWN(phys)));

		if (!ptr)

			return -EFAULT;

		r = copy_to_user(buf, ptr, n);

		kunmap(pfn_to_page(PFN_DOWN(phys)));

		if (r)

			return -EFAULT;

		*pos += n;

		size -= n;

		result += n;

	}

	return result;

}

	// always return 8 bytes

	if (size != 8)

		return -EINVAL;

static ssize_t amdgpu_iova_to_phys_write(struct file *f, const char __user *buf,

				   size_t size, loff_t *pos)

{

	struct amdgpu_device *adev = file_inode(f)->i_private;

	ssize_t result, n;

	int r;

	uint64_t phys;

	void *ptr;

	struct iommu_domain *dom;

	// only accept page addresses

	if (*pos & 0xFFF)

		return -EINVAL;

	dom = iommu_get_domain_for_dev(adev->dev);

	if (!dom)

		return -EFAULT;

	result = 0;

	while (size) {

		// get physical address and map

	if (dom)

		phys = iommu_iova_to_phys(dom, *pos);

		// copy upto one page

		if (size > PAGE_SIZE)

			n = PAGE_SIZE;

	else

			n = size;

		phys = *pos;

		// to end of the page

		if (((*pos & (PAGE_SIZE - 1)) + n) >= PAGE_SIZE)

			n = PAGE_SIZE - (*pos & (PAGE_SIZE - 1));

		ptr = kmap(pfn_to_page(PFN_DOWN(phys)));

		if (!ptr)

			return -EFAULT;

		r = copy_from_user(ptr, buf, n);

		kunmap(pfn_to_page(PFN_DOWN(phys)));

	r = copy_to_user(buf, &phys, 8);

	if (r)

		return -EFAULT;

		*pos += n;

		size -= n;

		result += n;

	}

	return result;

	return 8;

}

static const struct file_operations amdgpu_ttm_iova_fops = {

	.owner = THIS_MODULE,

	.read = amdgpu_iova_to_phys_read,

	.write = amdgpu_iova_to_phys_write,

	.llseek = default_llseek

};