[PATCH] drm/rockchip: support prime fd import

[Zach Reizner]

The prime fd to handle ioctl was not used with rockchip before. Support
was added in order to support potential uses (e.g. zero-copy video
decode, camera).

Signed-off-by: Zach Reizner <zachr at google.com>
---
 drivers/gpu/drm/rockchip/rockchip_drm_drv.c |  1 +
 drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 92 ++++++++++++++++++++++++++---
 drivers/gpu/drm/rockchip/rockchip_drm_gem.h |  7 ++-
 3 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
index dbfec29..4a01d92 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
@@ -307,6 +307,7 @@ static struct drm_driver rockchip_drm_driver = {
 	.gem_prime_import	= drm_gem_prime_import,
 	.gem_prime_export	= drm_gem_prime_export,
 	.gem_prime_get_sg_table	= rockchip_gem_prime_get_sg_table,
+	.gem_prime_import_sg_table	= rockchip_gem_prime_import_sg_table,
 	.gem_prime_vmap		= rockchip_gem_prime_vmap,
 	.gem_prime_vunmap	= rockchip_gem_prime_vunmap,
 	.gem_prime_mmap		= rockchip_gem_mmap_buf,
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index a5c512e..cf6b50b 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -19,6 +19,7 @@
 #include <drm/rockchip_drm.h>
 
 #include <linux/dma-attrs.h>
+#include <linux/dma-buf.h>
 
 #include "rockchip_drm_drv.h"
 #include "rockchip_drm_gem.h"
@@ -105,13 +106,11 @@ int rockchip_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 	return rockchip_drm_gem_object_mmap(obj, vma);
 }
 
-struct rockchip_gem_object *
-	rockchip_gem_create_object(struct drm_device *drm, unsigned int size,
-				   bool alloc_kmap)
+static struct rockchip_gem_object *
+	rockchip_gem_alloc_object(struct drm_device *drm, unsigned int size)
 {
 	struct rockchip_gem_object *rk_obj;
 	struct drm_gem_object *obj;
-	int ret;
 
 	size = round_up(size, PAGE_SIZE);
 
@@ -123,6 +122,20 @@ struct rockchip_gem_object *
 
 	drm_gem_private_object_init(drm, obj, size);
 
+	return rk_obj;
+}
+
+struct rockchip_gem_object *
+	rockchip_gem_create_object(struct drm_device *drm, unsigned int size,
+				   bool alloc_kmap)
+{
+	struct rockchip_gem_object *rk_obj;
+	int ret;
+
+	rk_obj = rockchip_gem_alloc_object(drm, size);
+	if (IS_ERR(rk_obj))
+		return rk_obj;
+
 	ret = rockchip_gem_alloc_buf(rk_obj, alloc_kmap);
 	if (ret)
 		goto err_free_rk_obj;
@@ -140,13 +153,18 @@ err_free_rk_obj:
  */
 void rockchip_gem_free_object(struct drm_gem_object *obj)
 {
-	struct rockchip_gem_object *rk_obj;
+	struct drm_device *drm = obj->dev;
+	struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
 
 	drm_gem_free_mmap_offset(obj);
 
-	rk_obj = to_rockchip_obj(obj);
-
-	rockchip_gem_free_buf(rk_obj);
+	if (rk_obj->sg) {
+		dma_unmap_sg(drm->dev, rk_obj->sg->sgl, rk_obj->sg->nents,
+			     DMA_BIDIRECTIONAL);
+		drm_prime_gem_destroy(obj, rk_obj->sg);
+	} else {
+		rockchip_gem_free_buf(rk_obj);
+	}
 
 	kfree(rk_obj);
 }
@@ -289,6 +307,64 @@ struct sg_table *rockchip_gem_prime_get_sg_table(struct drm_gem_object *obj)
 	return sgt;
 }
 
+static unsigned long rockchip_sg_get_contiguous_size(struct sg_table *sgt,
+						     int count)
+{
+	struct scatterlist *s;
+	dma_addr_t expected = sg_dma_address(sgt->sgl);
+	unsigned int i;
+	unsigned long size = 0;
+
+	for_each_sg(sgt->sgl, s, count, i) {
+		if (sg_dma_address(s) != expected)
+			break;
+		expected = sg_dma_address(s) + sg_dma_len(s);
+		size += sg_dma_len(s);
+	}
+	return size;
+}
+
+
+struct drm_gem_object *
+rockchip_gem_prime_import_sg_table(struct drm_device *drm,
+				   struct dma_buf_attachment *attach,
+				   struct sg_table *sg)
+{
+	struct rockchip_gem_object *rk_obj;
+	size_t size = attach->dmabuf->size;
+	int count;
+	int ret;
+
+	rk_obj = rockchip_gem_alloc_object(drm, size);
+	if (IS_ERR(rk_obj))
+		return ERR_CAST(rk_obj);
+
+	count = dma_map_sg(drm->dev, sg->sgl, sg->nents,
+			   DMA_BIDIRECTIONAL);
+
+	if (!count) {
+		ret = -EINVAL;
+		goto err_free_rk_obj;
+	}
+
+	if (rockchip_sg_get_contiguous_size(sg, count) < size) {
+		DRM_ERROR("failed to map sg_table to contiguous linear address.\n");
+		dma_unmap_sg(drm->dev, sg->sgl, sg->nents,
+			     DMA_BIDIRECTIONAL);
+		ret = -EINVAL;
+		goto err_free_rk_obj;
+	}
+
+	rk_obj->dma_addr = sg_dma_address(sg->sgl);
+	rk_obj->sg = sg;
+
+	return &rk_obj->base;
+
+err_free_rk_obj:
+	kfree(rk_obj);
+	return ERR_PTR(ret);
+}
+
 void *rockchip_gem_prime_vmap(struct drm_gem_object *obj)
 {
 	struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.h b/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
index d5d8010..b6dc3b1 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
@@ -17,6 +17,8 @@
 
 #define to_rockchip_obj(x) container_of(x, struct rockchip_gem_object, base)
 
+struct sg_table;
+
 struct rockchip_gem_object {
 	struct drm_gem_object base;
 	unsigned int flags;
@@ -24,11 +26,14 @@ struct rockchip_gem_object {
 	void *kvaddr;
 	dma_addr_t dma_addr;
 	struct dma_attrs dma_attrs;
+
+	struct sg_table *sg;
 };
 
 struct sg_table *rockchip_gem_prime_get_sg_table(struct drm_gem_object *obj);
 struct drm_gem_object *
-rockchip_gem_prime_import_sg_table(struct drm_device *dev, size_t size,
+rockchip_gem_prime_import_sg_table(struct drm_device *dev,
+				   struct dma_buf_attachment *attach,
 				   struct sg_table *sgt);
 void *rockchip_gem_prime_vmap(struct drm_gem_object *obj);
 void rockchip_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
-- 
2.7.0.rc3.207.g0ac5344