[PATCH 2/2] drm: GEM CMA: Add DRM PRIME support
Laurent Pinchart
laurent.pinchart+renesas at ideasonboard.com
Tue Mar 12 07:45:38 PDT 2013
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
---
drivers/gpu/drm/drm_gem_cma_helper.c | 311 ++++++++++++++++++++++++++++++++++-
include/drm/drm_gem_cma_helper.h | 9 +
2 files changed, 317 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index 8cce330..c428a51 100644
--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -21,6 +21,9 @@
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/export.h>
+#if CONFIG_DMA_SHARED_BUFFER
+#include <linux/dma-buf.h>
+#endif
#include <linux/dma-mapping.h>
#include <drm/drmP.h>
@@ -82,6 +85,8 @@ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
unsigned int size)
{
struct drm_gem_cma_object *cma_obj;
+ struct sg_table *sgt = NULL;
+ int ret;
size = round_up(size, PAGE_SIZE);
@@ -94,11 +99,29 @@ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
if (!cma_obj->vaddr) {
dev_err(drm->dev, "failed to allocate buffer with size %d\n",
size);
- drm_gem_cma_free_object(&cma_obj->base);
- return ERR_PTR(-ENOMEM);
+ ret = -ENOMEM;
+ goto error;
}
+ sgt = kzalloc(sizeof(*cma_obj->sgt), GFP_KERNEL);
+ if (sgt == NULL) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ ret = dma_get_sgtable(drm->dev, sgt, cma_obj->vaddr,
+ cma_obj->paddr, size);
+ if (ret < 0)
+ goto error;
+
+ cma_obj->sgt = sgt;
+
return cma_obj;
+
+error:
+ kfree(sgt);
+ drm_gem_cma_free_object(&cma_obj->base);
+ return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(drm_gem_cma_create);
@@ -156,9 +179,16 @@ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
cma_obj = to_drm_gem_cma_obj(gem_obj);
- if (cma_obj->vaddr)
+ if (cma_obj->vaddr) {
dma_free_writecombine(gem_obj->dev->dev, cma_obj->base.size,
cma_obj->vaddr, cma_obj->paddr);
+ if (cma_obj->sgt) {
+ sg_free_table(cma_obj->sgt);
+ kfree(cma_obj->sgt);
+ }
+ } else if (gem_obj->import_attach) {
+ drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
+ }
drm_gem_object_release(gem_obj);
@@ -282,4 +312,279 @@ void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj, struct seq_file *m
seq_printf(m, "\n");
}
EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
+
+/* -----------------------------------------------------------------------------
+ * DMA-BUF
+ */
+
+#if CONFIG_DMA_SHARED_BUFFER
+struct drm_gem_cma_dmabuf_attachment {
+ struct sg_table sgt;
+ enum dma_data_direction dir;
+};
+
+static int drm_gem_cma_dmabuf_attach(struct dma_buf *dmabuf, struct device *dev,
+ struct dma_buf_attachment *attach)
+{
+ struct drm_gem_cma_dmabuf_attachment *cma_attach;
+
+ cma_attach = kzalloc(sizeof(*cma_attach), GFP_KERNEL);
+ if (!cma_attach)
+ return -ENOMEM;
+
+ cma_attach->dir = DMA_NONE;
+ attach->priv = cma_attach;
+
+ return 0;
+}
+
+static void drm_gem_cma_dmabuf_detach(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *attach)
+{
+ struct drm_gem_cma_dmabuf_attachment *cma_attach = attach->priv;
+ struct sg_table *sgt;
+
+ if (cma_attach == NULL)
+ return;
+
+ sgt = &cma_attach->sgt;
+
+ if (cma_attach->dir != DMA_NONE)
+ dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
+ cma_attach->dir);
+
+ sg_free_table(sgt);
+ kfree(cma_attach);
+ attach->priv = NULL;
+}
+
+static struct sg_table *
+drm_gem_cma_dmabuf_map(struct dma_buf_attachment *attach,
+ enum dma_data_direction dir)
+{
+ struct drm_gem_cma_dmabuf_attachment *cma_attach = attach->priv;
+ struct drm_gem_cma_object *cma_obj = attach->dmabuf->priv;
+ struct drm_device *drm = cma_obj->base.dev;
+ struct scatterlist *rd, *wr;
+ struct sg_table *sgt;
+ unsigned int i;
+ int nents, ret;
+
+ DRM_DEBUG_PRIME("\n");
+
+ if (WARN_ON(dir == DMA_NONE))
+ return ERR_PTR(-EINVAL);
+
+ /* Return the cached mapping when possible. */
+ if (cma_attach->dir == dir)
+ return &cma_attach->sgt;
+
+ /* Two mappings with different directions for the same attachment are
+ * not allowed.
+ */
+ if (WARN_ON(cma_attach->dir != DMA_NONE))
+ return ERR_PTR(-EBUSY);
+
+ sgt = &cma_attach->sgt;
+
+ ret = sg_alloc_table(sgt, cma_obj->sgt->orig_nents, GFP_KERNEL);
+ if (ret) {
+ DRM_ERROR("failed to alloc sgt.\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ mutex_lock(&drm->struct_mutex);
+
+ rd = cma_obj->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);
+ }
+
+ nents = dma_map_sg(attach->dev, sgt->sgl, sgt->orig_nents, dir);
+ if (!nents) {
+ DRM_ERROR("failed to map sgl with iommu.\n");
+ sgt = ERR_PTR(-EIO);
+ goto err_unlock;
+ }
+
+ cma_attach->dir = dir;
+ attach->priv = cma_attach;
+
+ DRM_DEBUG_PRIME("buffer size = %zu\n", cma_obj->base.size);
+
+err_unlock:
+ mutex_unlock(&drm->struct_mutex);
+ return sgt;
+}
+
+static void drm_gem_cma_dmabuf_unmap(struct dma_buf_attachment *attach,
+ struct sg_table *sgt,
+ enum dma_data_direction dir)
+{
+ /* Nothing to do. */
+}
+
+static void drm_gem_cma_dmabuf_release(struct dma_buf *dmabuf)
+{
+ struct drm_gem_cma_object *cma_obj = dmabuf->priv;
+
+ DRM_DEBUG_PRIME("%s\n", __FILE__);
+
+ /*
+ * drm_gem_cma_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 (cma_obj->base.export_dma_buf == dmabuf) {
+ cma_obj->base.export_dma_buf = NULL;
+
+ /*
+ * drop this gem object refcount to release allocated buffer
+ * and resources.
+ */
+ drm_gem_object_unreference_unlocked(&cma_obj->base);
+ }
+}
+
+static void *drm_gem_cma_dmabuf_kmap_atomic(struct dma_buf *dmabuf,
+ unsigned long page_num)
+{
+ /* TODO */
+
+ return NULL;
+}
+
+static void drm_gem_cma_dmabuf_kunmap_atomic(struct dma_buf *dmabuf,
+ unsigned long page_num, void *addr)
+{
+ /* TODO */
+}
+
+static void *drm_gem_cma_dmabuf_kmap(struct dma_buf *dmabuf,
+ unsigned long page_num)
+{
+ /* TODO */
+
+ return NULL;
+}
+
+static void drm_gem_cma_dmabuf_kunmap(struct dma_buf *dmabuf,
+ unsigned long page_num, void *addr)
+{
+ /* TODO */
+}
+
+static int drm_gem_cma_dmabuf_mmap(struct dma_buf *dmabuf,
+ struct vm_area_struct *vma)
+{
+ return -ENOTTY;
+}
+
+static void *drm_gem_cma_dmabuf_vmap(struct dma_buf *dmabuf)
+{
+ struct drm_gem_cma_object *cma_obj = dmabuf->priv;
+
+ return cma_obj->vaddr;
+}
+
+static struct dma_buf_ops drm_gem_cma_dmabuf_ops = {
+ .attach = drm_gem_cma_dmabuf_attach,
+ .detach = drm_gem_cma_dmabuf_detach,
+ .map_dma_buf = drm_gem_cma_dmabuf_map,
+ .unmap_dma_buf = drm_gem_cma_dmabuf_unmap,
+ .kmap = drm_gem_cma_dmabuf_kmap,
+ .kmap_atomic = drm_gem_cma_dmabuf_kmap_atomic,
+ .kunmap = drm_gem_cma_dmabuf_kunmap,
+ .kunmap_atomic = drm_gem_cma_dmabuf_kunmap_atomic,
+ .mmap = drm_gem_cma_dmabuf_mmap,
+ .vmap = drm_gem_cma_dmabuf_vmap,
+ .release = drm_gem_cma_dmabuf_release,
+};
+
+struct dma_buf *drm_gem_cma_dmabuf_export(struct drm_device *drm,
+ struct drm_gem_object *obj, int flags)
+{
+ struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
+
+ return dma_buf_export(cma_obj, &drm_gem_cma_dmabuf_ops,
+ cma_obj->base.size, flags);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_dmabuf_export);
+
+struct drm_gem_object *drm_gem_cma_dmabuf_import(struct drm_device *drm,
+ struct dma_buf *dma_buf)
+{
+ struct drm_gem_cma_object *cma_obj;
+ struct dma_buf_attachment *attach;
+ struct sg_table *sgt;
+ int ret;
+
+ DRM_DEBUG_PRIME("%s\n", __FILE__);
+
+ /* is this one of own objects? */
+ if (dma_buf->ops == &drm_gem_cma_dmabuf_ops) {
+ struct drm_gem_object *obj;
+
+ cma_obj = dma_buf->priv;
+ obj = &cma_obj->base;
+
+ /* is it from our device? */
+ if (obj->dev == drm) {
+ /*
+ * Importing dmabuf exported from out own gem increases
+ * refcount on gem itself instead of f_count of dmabuf.
+ */
+ drm_gem_object_reference(obj);
+ dma_buf_put(dma_buf);
+ return obj;
+ }
+ }
+
+ /* Create a CMA GEM buffer. */
+ cma_obj = __drm_gem_cma_create(drm, dma_buf->size);
+ if (IS_ERR(cma_obj))
+ return ERR_PTR(PTR_ERR(cma_obj));
+
+ /* Attach to the buffer and map it. Make sure the mapping is contiguous
+ * on the device memory bus, as that's all we support.
+ */
+ attach = dma_buf_attach(dma_buf, drm->dev);
+ if (IS_ERR(attach)) {
+ ret = -EINVAL;
+ goto error_gem_free;
+ }
+
+ sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+ if (IS_ERR_OR_NULL(sgt)) {
+ ret = sgt ? PTR_ERR(sgt) : -ENOMEM;
+ goto error_buf_detach;
+ }
+
+ if (sgt->nents != 1) {
+ ret = -EINVAL;
+ goto error_buf_unmap;
+ }
+
+ cma_obj->base.import_attach = attach;
+ cma_obj->paddr = sg_dma_address(sgt->sgl);
+ cma_obj->sgt = sgt;
+
+ DRM_DEBUG_PRIME("dma_addr = 0x%x, size = %zu\n", cma_obj->paddr,
+ dma_buf->size);
+
+ return &cma_obj->base;
+
+error_buf_unmap:
+ dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
+error_buf_detach:
+ dma_buf_detach(dma_buf, attach);
+error_gem_free:
+ drm_gem_cma_free_object(&cma_obj->base);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_dmabuf_import);
#endif
diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
index 63397ce..6e17251 100644
--- a/include/drm/drm_gem_cma_helper.h
+++ b/include/drm/drm_gem_cma_helper.h
@@ -4,6 +4,9 @@
struct drm_gem_cma_object {
struct drm_gem_object base;
dma_addr_t paddr;
+ struct sg_table *sgt;
+
+ /* For objects with DMA memory allocated by GEM CMA */
void *vaddr;
};
@@ -45,4 +48,10 @@ extern const struct vm_operations_struct drm_gem_cma_vm_ops;
void drm_gem_cma_describe(struct drm_gem_cma_object *obj, struct seq_file *m);
#endif
+struct dma_buf *drm_gem_cma_dmabuf_export(struct drm_device *drm_dev,
+ struct drm_gem_object *obj,
+ int flags);
+struct drm_gem_object *drm_gem_cma_dmabuf_import(struct drm_device *drm_dev,
+ struct dma_buf *dma_buf);
+
#endif /* __DRM_GEM_CMA_HELPER_H__ */
--
1.8.1.5
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