radeon: show case how non HMM driver can export p2p for special vmawip-p2p-showcase

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 9920a6fc11bf..a7699194edf9 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -899,6 +899,67 @@ static vm_fault_t radeon_ttm_fault(struct vm_fault *vmf)
 	return ret;
 }
 
+static long radeon_ttm_p2p_map(struct vm_area_struct *vma,
+			       struct device *device,
+			       unsigned long start,
+			       unsigned long end,
+			       dma_addr_t *pa,
+			       bool write)
+{
+	struct ttm_buffer_object *bo;
+	struct radeon_device *rdev;
+	unsigned long i, npages;
+	struct radeon_bo *rbo;
+	long ret = 0;
+
+	bo = (struct ttm_buffer_object *)vmf->vma->vm_private_data;
+	if (bo == NULL)
+		return -EINVAL;
+	rdev = radeon_get_rdev(bo->bdev);
+	down_read(&rdev->pm.mclk_lock);
+
+	rbo = container_of(bo, struct radeon_bo, bo);
+
+	ret = ttm_bo_reserve(bo, true, true, NULL);
+	if (ret)
+		goto out;
+	ret = ttm_mem_io_lock(man, true);
+	if (ret)
+		goto out_reserve;
+	ret = ttm_mem_io_reserve_vm(bo);
+	if (ret)
+		goto out_io_lock;
+	if (!bo->mem.bus.is_iomem) {
+		/* Only allow to map GPU memory */
+		ret = -EINVAL;
+		goto out;
+	}
+
+	poff = ((start - vma->vm_start) >> PAGE_SHIFT) +
+		vma->vm_pgoff - drm_vma_node_start(&bo->vma_node);
+	npages = (end - start) >> PAGE_SHIFT;
+	for (i = 0; i < npages; ++i, ++poff) {
+		pa[i] = ttm_bo_io_mem_pfn(bo, poff);
+	}
+
+out_io_lock:
+	ttm_mem_io_unlock(man);
+out_reserve:
+	ttm_bo_unreserve(bo);
+out:
+	up_read(&rdev->pm.mclk_lock);
+	return ret ? ret :npages;
+}
+
+static long radeon_p2p_unmap(struct vm_area_struct *vma,
+			     struct device *device,
+			     unsigned long start,
+			     unsigned long end,
+			     dma_addr_t *pa)
+{
+	/* Nothing to do here. This is a crude example. */
+}
+
 int radeon_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct drm_file *file_priv;
@@ -922,6 +983,8 @@ int radeon_mmap(struct file *filp, struct vm_area_struct *vma)
 		ttm_vm_ops = vma->vm_ops;
 		radeon_ttm_vm_ops = *ttm_vm_ops;
 		radeon_ttm_vm_ops.fault = &radeon_ttm_fault;
+		radeon_ttm_vm_ops.p2p_map = radeon_ttm_p2p_map;
+		radeon_ttm_vm_ops.p2p_unmap = radeon_p2p_unmap;
 	}
 	vma->vm_ops = &radeon_ttm_vm_ops;
 	return 0;