drm/exynos: added drm prime feature.

this patch adds exynos specific codes for DRM Prime feature.
with this patch, user application can get file descriptor
from gem handle through DRM_IOCTL_PRIME_HANDLE_TO_FD ioctl
command(export) and also gem handle from file descriptor
through DRM_IOCTL_PRIME_FD_TO_HANLDE(import) ioctl command.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/Kconfig

@@ -10,6 +10,12 @@ config DRM_EXYNOS
 	  Choose this option if you have a Samsung SoC EXYNOS chipset.
 	  If M is selected the module will be called exynosdrm.
 
+config DRM_EXYNOS_DMABUF
+	bool "EXYNOS DRM DMABUF"
+	depends on DRM_EXYNOS
+	help
+	  Choose this option if you want to use DMABUF feature for DRM.
+
 config DRM_EXYNOS_FIMD
 	bool "Exynos DRM FIMD"
 	depends on DRM_EXYNOS && !FB_S3C

drivers/gpu/drm/exynos/Makefile

@@ -8,6 +8,7 @@ exynosdrm-y := exynos_drm_drv.o exynos_drm_encoder.o exynos_drm_connector.o \
 		exynos_drm_buf.o exynos_drm_gem.o exynos_drm_core.o \
 		exynos_drm_plane.o
 
+exynosdrm-$(CONFIG_DRM_EXYNOS_DMABUF) += exynos_drm_dmabuf.o
 exynosdrm-$(CONFIG_DRM_EXYNOS_FIMD)	+= exynos_drm_fimd.o
 exynosdrm-$(CONFIG_DRM_EXYNOS_HDMI)	+= exynos_hdmi.o exynos_mixer.o \
 					   exynos_ddc.o exynos_hdmiphy.o \

drivers/gpu/drm/exynos/exynos_drm_buf.c

@@ -35,7 +35,7 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
 		unsigned int flags, struct exynos_drm_gem_buf *buf)
 {
 	dma_addr_t start_addr;
-	unsigned int npages, page_size, i = 0;
+	unsigned int npages, i = 0;
 	struct scatterlist *sgl;
 	int ret = 0;
 
@@ -53,13 +53,13 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
 
 	if (buf->size >= SZ_1M) {
 		npages = buf->size >> SECTION_SHIFT;
-		page_size = SECTION_SIZE;
+		buf->page_size = SECTION_SIZE;
 	} else if (buf->size >= SZ_64K) {
 		npages = buf->size >> 16;
-		page_size = SZ_64K;
+		buf->page_size = SZ_64K;
 	} else {
 		npages = buf->size >> PAGE_SHIFT;
-		page_size = PAGE_SIZE;
+		buf->page_size = PAGE_SIZE;
 	}
 
 	buf->sgt = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
@@ -96,9 +96,9 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
 
 	while (i < npages) {
 		buf->pages[i] = phys_to_page(start_addr);
-		sg_set_page(sgl, buf->pages[i], page_size, 0);
+		sg_set_page(sgl, buf->pages[i], buf->page_size, 0);
 		sg_dma_address(sgl) = start_addr;
-		start_addr += page_size;
+		start_addr += buf->page_size;
 		sgl = sg_next(sgl);
 		i++;
 	}

drivers/gpu/drm/exynos/exynos_drm_dmabuf.c

@@ -0,0 +1,272 @@
+/* exynos_drm_dmabuf.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ * Author: Inki Dae <inki.dae@samsung.com>
+ *
+ * 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 (including the next
+ * paragraph) 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
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS 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.
+ */
+
+#include "drmP.h"
+#include "drm.h"
+#include "exynos_drm_drv.h"
+#include "exynos_drm_gem.h"
+
+#include <linux/dma-buf.h>
+
+static struct sg_table *exynos_pages_to_sg(struct page **pages, int nr_pages,
+		unsigned int page_size)
+{
+	struct sg_table *sgt = NULL;
+	struct scatterlist *sgl;
+	int i, ret;
+
+	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+	if (!sgt)
+		goto out;
+
+	ret = sg_alloc_table(sgt, nr_pages, GFP_KERNEL);
+	if (ret)
+		goto err_free_sgt;
+
+	if (page_size < PAGE_SIZE)
+		page_size = PAGE_SIZE;
+
+	for_each_sg(sgt->sgl, sgl, nr_pages, i)
+		sg_set_page(sgl, pages[i], page_size, 0);
+
+	return sgt;
+
+err_free_sgt:
+	kfree(sgt);
+	sgt = NULL;
+out:
+	return NULL;
+}
+
+static struct sg_table *
+		exynos_gem_map_dma_buf(struct dma_buf_attachment *attach,
+					enum dma_data_direction dir)
+{
+	struct exynos_drm_gem_obj *gem_obj = attach->dmabuf->priv;
+	struct drm_device *dev = gem_obj->base.dev;
+	struct exynos_drm_gem_buf *buf;
+	struct sg_table *sgt = NULL;
+	unsigned int npages;
+	int nents;
+
+	DRM_DEBUG_PRIME("%s\n", __FILE__);
+
+	mutex_lock(&dev->struct_mutex);
+
+	buf = gem_obj->buffer;
+
+	/* there should always be pages allocated. */
+	if (!buf->pages) {
+		DRM_ERROR("pages is null.\n");
+		goto err_unlock;
+	}
+
+	npages = buf->size / buf->page_size;
+
+	sgt = exynos_pages_to_sg(buf->pages, npages, buf->page_size);
+	nents = dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+
+	DRM_DEBUG_PRIME("npages = %d buffer size = 0x%lx page_size = 0x%lx\n",
+			npages, buf->size, buf->page_size);
+
+err_unlock:
+	mutex_unlock(&dev->struct_mutex);
+	return sgt;
+}
+
+static void exynos_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
+						struct sg_table *sgt,
+						enum dma_data_direction dir)
+{
+	dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+	sg_free_table(sgt);
+	kfree(sgt);
+	sgt = NULL;
+}
+
+static void exynos_dmabuf_release(struct dma_buf *dmabuf)
+{
+	struct exynos_drm_gem_obj *exynos_gem_obj = dmabuf->priv;
+
+	DRM_DEBUG_PRIME("%s\n", __FILE__);
+
+	/*
+	 * exynos_dmabuf_release() call means that file object's
+	 * f_count is 0 and it calls drm_gem_object_handle_unreference()
+	 * to drop the references that these values had been increased
+	 * at drm_prime_handle_to_fd()
+	 */
+	if (exynos_gem_obj->base.export_dma_buf == dmabuf) {
+		exynos_gem_obj->base.export_dma_buf = NULL;
+
+		/*
+		 * drop this gem object refcount to release allocated buffer
+		 * and resources.
+		 */
+		drm_gem_object_unreference_unlocked(&exynos_gem_obj->base);
+	}
+}
+
+static void *exynos_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
+						unsigned long page_num)
+{
+	/* TODO */
+
+	return NULL;
+}
+
+static void exynos_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
+						unsigned long page_num,
+						void *addr)
+{
+	/* TODO */
+}
+
+static void *exynos_gem_dmabuf_kmap(struct dma_buf *dma_buf,
+					unsigned long page_num)
+{
+	/* TODO */
+
+	return NULL;
+}
+
+static void exynos_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
+					unsigned long page_num, void *addr)
+{
+	/* TODO */
+}
+
+static struct dma_buf_ops exynos_dmabuf_ops = {
+	.map_dma_buf		= exynos_gem_map_dma_buf,
+	.unmap_dma_buf		= exynos_gem_unmap_dma_buf,
+	.kmap			= exynos_gem_dmabuf_kmap,
+	.kmap_atomic		= exynos_gem_dmabuf_kmap_atomic,
+	.kunmap			= exynos_gem_dmabuf_kunmap,
+	.kunmap_atomic		= exynos_gem_dmabuf_kunmap_atomic,
+	.release		= exynos_dmabuf_release,
+};
+
+struct dma_buf *exynos_dmabuf_prime_export(struct drm_device *drm_dev,
+				struct drm_gem_object *obj, int flags)
+{
+	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
+
+	return dma_buf_export(exynos_gem_obj, &exynos_dmabuf_ops,
+				exynos_gem_obj->base.size, 0600);
+}
+
+struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
+				struct dma_buf *dma_buf)
+{
+	struct dma_buf_attachment *attach;
+	struct sg_table *sgt;
+	struct scatterlist *sgl;
+	struct exynos_drm_gem_obj *exynos_gem_obj;
+	struct exynos_drm_gem_buf *buffer;
+	struct page *page;
+	int ret, i = 0;
+
+	DRM_DEBUG_PRIME("%s\n", __FILE__);
+
+	/* is this one of own objects? */
+	if (dma_buf->ops == &exynos_dmabuf_ops) {
+		struct drm_gem_object *obj;
+
+		exynos_gem_obj = dma_buf->priv;
+		obj = &exynos_gem_obj->base;
+
+		/* is it from our device? */
+		if (obj->dev == drm_dev) {
+			drm_gem_object_reference(obj);
+			return obj;
+		}
+	}
+
+	attach = dma_buf_attach(dma_buf, drm_dev->dev);
+	if (IS_ERR(attach))
+		return ERR_PTR(-EINVAL);
+
+
+	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+	if (IS_ERR(sgt)) {
+		ret = PTR_ERR(sgt);
+		goto err_buf_detach;
+	}
+
+	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+	if (!buffer) {
+		DRM_ERROR("failed to allocate exynos_drm_gem_buf.\n");
+		ret = -ENOMEM;
+		goto err_unmap_attach;
+	}
+
+	buffer->pages = kzalloc(sizeof(*page) * sgt->nents, GFP_KERNEL);
+	if (!buffer->pages) {
+		DRM_ERROR("failed to allocate pages.\n");
+		ret = -ENOMEM;
+		goto err_free_buffer;
+	}
+
+	exynos_gem_obj = exynos_drm_gem_init(drm_dev, dma_buf->size);
+	if (!exynos_gem_obj) {
+		ret = -ENOMEM;
+		goto err_free_pages;
+	}
+
+	sgl = sgt->sgl;
+	buffer->dma_addr = sg_dma_address(sgl);
+
+	while (i < sgt->nents) {
+		buffer->pages[i] = sg_page(sgl);
+		buffer->size += sg_dma_len(sgl);
+		sgl = sg_next(sgl);
+		i++;
+	}
+
+	exynos_gem_obj->buffer = buffer;
+	buffer->sgt = sgt;
+	exynos_gem_obj->base.import_attach = attach;
+
+	DRM_DEBUG_PRIME("dma_addr = 0x%x, size = 0x%lx\n", buffer->dma_addr,
+								buffer->size);
+
+	return &exynos_gem_obj->base;
+
+err_free_pages:
+	kfree(buffer->pages);
+	buffer->pages = NULL;
+err_free_buffer:
+	kfree(buffer);
+	buffer = NULL;
+err_unmap_attach:
+	dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
+err_buf_detach:
+	dma_buf_detach(dma_buf, attach);
+	return ERR_PTR(ret);
+}
+
+MODULE_AUTHOR("Inki Dae <inki.dae@samsung.com>");
+MODULE_DESCRIPTION("Samsung SoC DRM DMABUF Module");
+MODULE_LICENSE("GPL");

drivers/gpu/drm/exynos/exynos_drm_dmabuf.h

@@ -0,0 +1,39 @@
+/* exynos_drm_dmabuf.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ * Author: Inki Dae <inki.dae@samsung.com>
+ *
+ * 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 (including the next
+ * paragraph) 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
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS 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.
+ */
+
+#ifndef _EXYNOS_DRM_DMABUF_H_
+#define _EXYNOS_DRM_DMABUF_H_
+
+#ifdef CONFIG_DRM_EXYNOS_DMABUF
+struct dma_buf *exynos_dmabuf_prime_export(struct drm_device *drm_dev,
+				struct drm_gem_object *obj, int flags);
+
+struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
+						struct dma_buf *dma_buf);
+#else
+#define exynos_dmabuf_prime_export		NULL
+#define exynos_dmabuf_prime_import		NULL
+#endif
+#endif