1 files changed, 308 insertions, 0 deletions
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
new file mode 100644
index 0000000..ff7f2a8
--- /dev/null
+++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
@@ -0,0 +1,308 @@
+/* exynos_drm_dmabuf.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ * Author: Inki Dae <inki.dae@samsung.com>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <drm/drmP.h>
+#include <drm/exynos_drm.h>
+#include "exynos_drm_drv.h"
+#include "exynos_drm_gem.h"
+
+#include <linux/dma-buf.h>
+
+struct exynos_drm_dmabuf_attachment {
+	struct sg_table sgt;
+	enum dma_data_direction dir;
+	bool is_mapped;
+};
+
+static int exynos_gem_attach_dma_buf(struct dma_buf *dmabuf,
+					struct device *dev,
+					struct dma_buf_attachment *attach)
+{
+	struct exynos_drm_dmabuf_attachment *exynos_attach;
+
+	exynos_attach = kzalloc(sizeof(*exynos_attach), GFP_KERNEL);
+	if (!exynos_attach)
+		return -ENOMEM;
+
+	exynos_attach->dir = DMA_NONE;
+	attach->priv = exynos_attach;
+
+	return 0;
+}
+
+static void exynos_gem_detach_dma_buf(struct dma_buf *dmabuf,
+					struct dma_buf_attachment *attach)
+{
+	struct exynos_drm_dmabuf_attachment *exynos_attach = attach->priv;
+	struct sg_table *sgt;
+
+	if (!exynos_attach)
+		return;
+
+	sgt = &exynos_attach->sgt;
+
+	if (exynos_attach->dir != DMA_NONE)
+		dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
+				exynos_attach->dir);
+
+	sg_free_table(sgt);
+	kfree(exynos_attach);
+	attach->priv = NULL;
+}
+
+static struct sg_table *
+		exynos_gem_map_dma_buf(struct dma_buf_attachment *attach,
+					enum dma_data_direction dir)
+{
+	struct exynos_drm_dmabuf_attachment *exynos_attach = attach->priv;
+	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 scatterlist *rd, *wr;
+	struct sg_table *sgt = NULL;
+	unsigned int i;
+	int nents, ret;
+
+	DRM_DEBUG_PRIME("%s\n", __FILE__);
+
+	/* just return current sgt if already requested. */
+	if (exynos_attach->dir == dir && exynos_attach->is_mapped)
+		return &exynos_attach->sgt;
+
+	buf = gem_obj->buffer;
+	if (!buf) {
+		DRM_ERROR("buffer is null.\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	sgt = &exynos_attach->sgt;
+
+	ret = sg_alloc_table(sgt, buf->sgt->orig_nents, GFP_KERNEL);
+	if (ret) {
+		DRM_ERROR("failed to alloc sgt.\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	mutex_lock(&dev->struct_mutex);
+
+	rd = buf->sgt->sgl;
+	wr = sgt->sgl;
+	for (i = 0; i < sgt->orig_nents; ++i) {
+		sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
+		rd = sg_next(rd);
+		wr = sg_next(wr);
+	}
+
+	if (dir != DMA_NONE) {
+		nents = dma_map_sg(attach->dev, sgt->sgl, sgt->orig_nents, dir);
+		if (!nents) {
+			DRM_ERROR("failed to map sgl with iommu.\n");
+			sg_free_table(sgt);
+			sgt = ERR_PTR(-EIO);
+			goto err_unlock;
+		}
+	}
+
+	exynos_attach->is_mapped = true;
+	exynos_attach->dir = dir;
+	attach->priv = exynos_attach;
+
+	DRM_DEBUG_PRIME("buffer size = 0x%lx\n", buf->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)
+{
+	/* Nothing to do. */
+}
+
+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 int exynos_gem_dmabuf_mmap(struct dma_buf *dma_buf,
+	struct vm_area_struct *vma)
+{
+	return -ENOTTY;
+}
+
+static struct dma_buf_ops exynos_dmabuf_ops = {
+	.attach			= exynos_gem_attach_dma_buf,
+	.detach			= exynos_gem_detach_dma_buf,
+	.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,
+	.mmap			= exynos_gem_dmabuf_mmap,
+	.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, flags);
+}
+
+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;
+	int ret;
+
+	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) {
+			/*
+			 * Importing dmabuf exported from out own gem increases
+			 * refcount on gem itself instead of f_count of dmabuf.
+			 */
+			drm_gem_object_reference(obj);
+			return obj;
+		}
+	}
+
+	attach = dma_buf_attach(dma_buf, drm_dev->dev);
+	if (IS_ERR(attach))
+		return ERR_PTR(-EINVAL);
+
+	get_dma_buf(dma_buf);
+
+	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+	if (IS_ERR_OR_NULL(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;
+	}
+
+	exynos_gem_obj = exynos_drm_gem_init(drm_dev, dma_buf->size);
+	if (!exynos_gem_obj) {
+		ret = -ENOMEM;
+		goto err_free_buffer;
+	}
+
+	sgl = sgt->sgl;
+
+	buffer->size = dma_buf->size;
+	buffer->dma_addr = sg_dma_address(sgl);
+
+	if (sgt->nents == 1) {
+		/* always physically continuous memory if sgt->nents is 1. */
+		exynos_gem_obj->flags |= EXYNOS_BO_CONTIG;
+	} else {
+		/*
+		 * this case could be CONTIG or NONCONTIG type but for now
+		 * sets NONCONTIG.
+		 * TODO. we have to find a way that exporter can notify
+		 * the type of its own buffer to importer.
+		 */
+		exynos_gem_obj->flags |= EXYNOS_BO_NONCONTIG;
+	}
+
+	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_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);
+	dma_buf_put(dma_buf);
+
+	return ERR_PTR(ret);
+}
+
+MODULE_AUTHOR("Inki Dae <inki.dae@samsung.com>");
+MODULE_DESCRIPTION("Samsung SoC DRM DMABUF Module");
+MODULE_LICENSE("GPL");