[PATCH v2] drm/ast: add dmabuf/prime buffer sharing support

[oushixiong]

This patch adds ast specific codes for DRM prime feature, this is to
allow for offloading of rending in one direction and outputs in other.

v1->v2:
  - Fix the comment.

Signed-off-by: oushixiong <oushixiong@xxxxxxxxxx>
---
 drivers/gpu/drm/ast/ast_drv.c  |  22 ++++++
 drivers/gpu/drm/ast/ast_mode.c | 125 ++++++++++++++++++++++++++++++++-
 2 files changed, 146 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 7465c4f0156a..6c1f75174368 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -28,6 +28,7 @@
 
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/dma-buf.h>
 
 #include <drm/drm_aperture.h>
 #include <drm/drm_atomic_helper.h>
@@ -50,6 +51,23 @@ module_param_named(modeset, ast_modeset, int, 0400);
 
 DEFINE_DRM_GEM_FOPS(ast_fops);
 
+static struct drm_gem_object *ast_gem_prime_import_sg_table(struct drm_device *dev,
+					struct dma_buf_attachment *attach,
+					struct sg_table *sg)
+{
+	struct drm_gem_vram_object *gbo;
+	struct dma_resv *resv = attach->dmabuf->resv;
+
+	ww_mutex_lock(&resv->lock, NULL);
+	gbo = drm_gem_vram_create(dev, attach->dmabuf->size, 0);
+	ww_mutex_unlock(&resv->lock);
+
+	if (IS_ERR(gbo))
+		return NULL;
+
+	return &gbo->bo.base;
+}
+
 static const struct drm_driver ast_driver = {
 	.driver_features = DRIVER_ATOMIC |
 			   DRIVER_GEM |
@@ -63,6 +81,10 @@ static const struct drm_driver ast_driver = {
 	.minor = DRIVER_MINOR,
 	.patchlevel = DRIVER_PATCHLEVEL,
 
+	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
+	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
+	.gem_prime_import_sg_table = ast_gem_prime_import_sg_table,
+
 	DRM_GEM_VRAM_DRIVER
 };
 
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 45b56b39ad47..ebe732705e34 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -48,6 +48,8 @@
 #include "ast_drv.h"
 #include "ast_tables.h"
 
+MODULE_IMPORT_NS(DMA_BUF);
+
 static inline void ast_load_palette_index(struct ast_private *ast,
 				     u8 index, u8 red, u8 green,
 				     u8 blue)
@@ -1535,8 +1537,129 @@ static const struct drm_mode_config_helper_funcs ast_mode_config_helper_funcs =
 	.atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
 };
 
+static int ast_handle_damage(struct drm_framebuffer *fb, int x, int y,
+					int width, int height)
+{
+	struct drm_gem_vram_object *dst_bo = NULL;
+	void *dst = NULL;
+	int ret = 0, i;
+	unsigned long offset = 0;
+	bool unmap = false;
+	unsigned int bytesPerPixel;
+	struct iosys_map map;
+	struct iosys_map dmabuf_map;
+
+	bytesPerPixel = fb->format->cpp[0];
+
+	if (!fb->obj[0]->import_attach)
+		return -EINVAL;
+
+	if (!fb->obj[0]->import_attach->dmabuf->vmap_ptr.vaddr) {
+		ret = dma_buf_vmap(fb->obj[0]->import_attach->dmabuf, &dmabuf_map);
+		if (ret)
+			return 0;
+	} else
+		dmabuf_map.vaddr = fb->obj[0]->import_attach->dmabuf->vmap_ptr.vaddr;
+
+	dst_bo = drm_gem_vram_of_gem(fb->obj[0]);
+
+	ret = drm_gem_vram_pin(dst_bo, 0);
+	if (ret) {
+		DRM_ERROR("ast_bo_pin failed\n");
+		goto error;
+	}
+
+	if (!dst_bo->map.vaddr) {
+		ret = drm_gem_vram_vmap(dst_bo, &map);
+		if (ret) {
+			DRM_ERROR("failed to vmap fbcon\n");
+			drm_gem_vram_unpin(dst_bo);
+			goto error;
+		}
+		unmap = true;
+	}
+	dst = dst_bo->map.vaddr;
+
+	for (i = y; i < y + height; i++) {
+		offset = i * fb->pitches[0] + (x * bytesPerPixel);
+		memcpy_toio(dst + offset, dmabuf_map.vaddr + offset,
+			width * bytesPerPixel);
+	}
+
+	if (unmap)
+		drm_gem_vram_vunmap(dst_bo, &map);
+
+	drm_gem_vram_unpin(dst_bo);
+error:
+	return 0;
+}
+
+
+static int ast_user_framebuffer_dirty(struct drm_framebuffer *fb,
+				struct drm_file *file,
+				unsigned int flags,
+				unsigned int color,
+				struct drm_clip_rect *clips,
+				unsigned int num_clips)
+{
+	int i, ret = 0;
+
+	drm_modeset_lock_all(fb->dev);
+	if (fb->obj[0]->import_attach) {
+		ret = dma_buf_begin_cpu_access(fb->obj[0]->import_attach->dmabuf,
+				DMA_FROM_DEVICE);
+		if (ret)
+			goto unlock;
+	}
+
+	for (i = 0; i < num_clips; i++) {
+		ret = ast_handle_damage(fb, clips[i].x1, clips[i].y1,
+				clips[i].x2 - clips[i].x1, clips[i].y2 - clips[i].y1);
+		if (ret)
+			break;
+	}
+
+	if (fb->obj[0]->import_attach) {
+		dma_buf_end_cpu_access(fb->obj[0]->import_attach->dmabuf,
+				DMA_FROM_DEVICE);
+	}
+
+unlock:
+	drm_modeset_unlock_all(fb->dev);
+
+	return ret;
+}
+
+static void ast_user_framebuffer_destroy(struct drm_framebuffer *fb)
+{
+	struct iosys_map dmabuf_map;
+
+	if (fb->obj[0]->import_attach) {
+		dmabuf_map.vaddr = fb->obj[0]->import_attach->dmabuf->vmap_ptr.vaddr;
+		if (dmabuf_map.vaddr)
+			dma_buf_vunmap(fb->obj[0]->import_attach->dmabuf,
+					&dmabuf_map);
+	}
+
+	drm_gem_fb_destroy(fb);
+}
+
+static const struct drm_framebuffer_funcs ast_gem_fb_funcs_dirtyfb = {
+	.destroy	= ast_user_framebuffer_destroy,
+	.create_handle	= drm_gem_fb_create_handle,
+	.dirty		= ast_user_framebuffer_dirty,
+};
+
+static struct drm_framebuffer *
+ast_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
+				const struct drm_mode_fb_cmd2 *mode_cmd)
+{
+	return drm_gem_fb_create_with_funcs(dev, file, mode_cmd,
+					&ast_gem_fb_funcs_dirtyfb);
+}
+
 static const struct drm_mode_config_funcs ast_mode_config_funcs = {
-	.fb_create = drm_gem_fb_create,
+	.fb_create = ast_gem_fb_create_with_dirty,
 	.mode_valid = drm_vram_helper_mode_valid,
 	.atomic_check = drm_atomic_helper_check,
 	.atomic_commit = drm_atomic_helper_commit,
-- 
2.17.1