Hi Laurent, a few mostly-minor comments, although from a quick look the sg_alloc_table()/sg_free_table() doesn't look quite right in all cases. The other comments could just be a subject for a later patch if it is something that somebody needs some day..
On Mon, Apr 15, 2013 at 9:57 AM, Laurent Pinchart laurent.pinchart+renesas@ideasonboard.com wrote:
Signed-off-by: Laurent Pinchart laurent.pinchart+renesas@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;
don't we miss a sg_free_table() in this error path? Or, well, I guess you still call it in _detach(), but if you call _map() again, I think we'll re-sg_alloc_table(), which doesn't seem quite right..
}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. */
hmm, I wonder if it makes sense to support _unmap() and then _map() again with a different direction? Not entirely sure when that would be needed and I suppose it is ok to add later.
+}
+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 */+}
again, not really sure if it is required, but it should be pretty trivial to support kmap and friends
+static int drm_gem_cma_dmabuf_mmap(struct dma_buf *dmabuf,
struct vm_area_struct *vma)+{
return -ENOTTY;+}
should also be pretty trivial to redirect _dmabuf_mmap() into drm_gem_cma_mmap()..
+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