drm/radeon: add PRIME support (v2)

This adds prime->fd and fd->prime support to radeon.
It passes the sg object to ttm and then populates
the gart entries using it.

Compile tested only.

v2: stub kmap + use new helpers + add reimporting

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_prime.c b/drivers/gpu/drm/radeon/radeon_prime.c
new file mode 100644
index 0000000..24f5175
--- /dev/null
+++ b/drivers/gpu/drm/radeon/radeon_prime.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright 2012 Advanced Micro Devices, 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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.
+ *
+ * based on nouveau_prime.c
+ *
+ * Authors: Alex Deucher
+ */
+#include "drmP.h"
+#include "drm.h"
+
+#include "radeon.h"
+#include "radeon_drm.h"
+
+#include <linux/dma-buf.h>
+
+static struct sg_table *radeon_gem_map_dma_buf(struct dma_buf_attachment *attachment,
+					       enum dma_data_direction dir)
+{
+	struct radeon_bo *bo = attachment->dmabuf->priv;
+	struct drm_device *dev = bo->rdev->ddev;
+	int npages = bo->tbo.num_pages;
+	struct sg_table *sg;
+	int nents;
+
+	mutex_lock(&dev->struct_mutex);
+	sg = drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages);
+	nents = dma_map_sg(attachment->dev, sg->sgl, sg->nents, dir);
+	mutex_unlock(&dev->struct_mutex);
+	return sg;
+}
+
+static void radeon_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 radeon_gem_dmabuf_release(struct dma_buf *dma_buf)
+{
+	struct radeon_bo *bo = dma_buf->priv;
+
+	if (bo->gem_base.export_dma_buf == dma_buf) {
+		DRM_ERROR("unreference dmabuf %p\n", &bo->gem_base);
+		bo->gem_base.export_dma_buf = NULL;
+		drm_gem_object_unreference_unlocked(&bo->gem_base);
+	}
+}
+
+static void *radeon_gem_kmap_atomic(struct dma_buf *dma_buf, unsigned long page_num)
+{
+	return NULL;
+}
+
+static void radeon_gem_kunmap_atomic(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
+{
+
+}
+static void *radeon_gem_kmap(struct dma_buf *dma_buf, unsigned long page_num)
+{
+	return NULL;
+}
+
+static void radeon_gem_kunmap(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
+{
+
+}
+
+struct dma_buf_ops radeon_dmabuf_ops =  {
+	.map_dma_buf = radeon_gem_map_dma_buf,
+	.unmap_dma_buf = radeon_gem_unmap_dma_buf,
+	.release = radeon_gem_dmabuf_release,
+	.kmap = radeon_gem_kmap,
+	.kmap_atomic = radeon_gem_kmap_atomic,
+	.kunmap = radeon_gem_kunmap,
+	.kunmap_atomic = radeon_gem_kunmap_atomic,
+};
+
+static int radeon_prime_create(struct drm_device *dev,
+			       size_t size,
+			       struct sg_table *sg,
+			       struct radeon_bo **pbo)
+{
+	struct radeon_device *rdev = dev->dev_private;
+	struct radeon_bo *bo;
+	int ret;
+
+	ret = radeon_bo_create(rdev, size, PAGE_SIZE, false,
+			       RADEON_GEM_DOMAIN_GTT, sg, pbo);
+	if (ret)
+		return ret;
+	bo = *pbo;
+	bo->gem_base.driver_private = bo;
+
+	mutex_lock(&rdev->gem.mutex);
+	list_add_tail(&bo->list, &rdev->gem.objects);
+	mutex_unlock(&rdev->gem.mutex);
+
+	return 0;
+}
+
+struct dma_buf *radeon_gem_prime_export(struct drm_device *dev,
+					struct drm_gem_object *obj,
+					int flags)
+{
+	struct radeon_bo *bo = gem_to_radeon_bo(obj);
+	int ret = 0;
+
+	/* pin buffer into GTT */
+	ret = radeon_bo_pin(bo, RADEON_GEM_DOMAIN_GTT, NULL);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return dma_buf_export(bo, &radeon_dmabuf_ops, obj->size, flags);
+}
+
+struct drm_gem_object *radeon_gem_prime_import(struct drm_device *dev,
+					       struct dma_buf *dma_buf)
+{
+	struct dma_buf_attachment *attach;
+	struct sg_table *sg;
+	struct radeon_bo *bo;
+	int ret;
+
+	if (dma_buf->ops == &radeon_dmabuf_ops) {
+		bo = dma_buf->priv;
+		if (bo->gem_base.dev == dev) {
+			drm_gem_object_reference(&bo->gem_base);
+			return &bo->gem_base;
+		}
+	}
+
+	/* need to attach */
+	attach = dma_buf_attach(dma_buf, dev->dev);
+	if (IS_ERR(attach))
+		return ERR_CAST(attach);
+
+	sg = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+	if (IS_ERR(sg)) {
+		ret = PTR_ERR(sg);
+		goto fail_detach;
+	}
+
+	ret = radeon_prime_create(dev, dma_buf->size, sg, &bo);
+	if (ret)
+		goto fail_unmap;
+
+	bo->gem_base.import_attach = attach;
+
+	return &bo->gem_base;
+
+fail_unmap:
+	dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
+fail_detach:
+	dma_buf_detach(dma_buf, attach);
+	return ERR_PTR(ret);
+}