The drm_gem_mmap() function first finds the GEM object to be mapped based on the fake mmap offset and then maps the object. Split the object mapping code into a standalone drm_gem_mmap_obj() function that can be used to implement dma-buf mmap() operations.

Signed-off-by: Laurent Pinchart laurent.pinchart+renesas@ideasonboard.com Reviewed-by: Rob Clark robdclark@gmail.com --- drivers/gpu/drm/drm_gem.c | 83 +++++++++++++++++++++++++++++------------------ include/drm/drmP.h | 2 ++ 2 files changed, 54 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index cf919e3..4321713 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -644,6 +644,55 @@ void drm_gem_vm_close(struct vm_area_struct *vma) } EXPORT_SYMBOL(drm_gem_vm_close);

+/** + * drm_gem_mmap_obj - memory map a GEM object + * @obj: the GEM object to map + * @obj_size: the object size to be mapped, in bytes + * @vma: VMA for the area to be mapped + * + * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops + * provided by the driver. Depending on their requirements, drivers can either + * provide a fault handler in their gem_vm_ops (in which case any accesses to + * the object will be trapped, to perform migration, GTT binding, surface + * register allocation, or performance monitoring), or mmap the buffer memory + * synchronously after calling drm_gem_mmap_obj. + * + * This function is mainly intended to implement the DMABUF mmap operation, when + * the GEM object is not looked up based on its fake offset. To implement the + * DRM mmap operation, drivers should use the drm_gem_mmap() function. + * + * Return 0 or success or -EINVAL if the object size is smaller than the VMA + * size, or if no gem_vm_ops are provided. + */ +int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, + struct vm_area_struct *vma) +{ + struct drm_device *dev = obj->dev; + + /* Check for valid size. */ + if (obj_size < vma->vm_end - vma->vm_start) + return -EINVAL; + + if (!dev->driver->gem_vm_ops) + return -EINVAL; + + vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_ops = dev->driver->gem_vm_ops; + vma->vm_private_data = obj; + vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags)); + + /* Take a ref for this mapping of the object, so that the fault + * handler can dereference the mmap offset's pointer to the object. + * This reference is cleaned up by the corresponding vm_close + * (which should happen whether the vma was created by this call, or + * by a vm_open due to mremap or partial unmap or whatever). + */ + drm_gem_object_reference(obj); + + drm_vm_open_locked(dev, vma); + return 0; +} +EXPORT_SYMBOL(drm_gem_mmap_obj);

/** * drm_gem_mmap - memory map routine for GEM objects @@ -653,11 +702,9 @@ EXPORT_SYMBOL(drm_gem_vm_close); * If a driver supports GEM object mapping, mmap calls on the DRM file * descriptor will end up here. * - * If we find the object based on the offset passed in (vma->vm_pgoff will + * Look up the GEM object based on the offset passed in (vma->vm_pgoff will * contain the fake offset we created when the GTT map ioctl was called on - * the object), we set up the driver fault handler so that any accesses - * to the object can be trapped, to perform migration, GTT binding, surface - * register allocation, or performance monitoring. + * the object) and map it with a call to drm_gem_mmap_obj(). */ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) { @@ -665,7 +712,6 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) struct drm_device *dev = priv->minor->dev; struct drm_gem_mm *mm = dev->mm_private; struct drm_local_map *map = NULL; - struct drm_gem_object *obj; struct drm_hash_item *hash; int ret = 0;

@@ -686,32 +732,7 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) goto out_unlock; }

- /* Check for valid size. */ - if (map->size < vma->vm_end - vma->vm_start) { - ret = -EINVAL; - goto out_unlock; - } - - obj = map->handle; - if (!obj->dev->driver->gem_vm_ops) { - ret = -EINVAL; - goto out_unlock; - } - - vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; - vma->vm_ops = obj->dev->driver->gem_vm_ops; - vma->vm_private_data = map->handle; - vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags)); - - /* Take a ref for this mapping of the object, so that the fault - * handler can dereference the mmap offset's pointer to the object. - * This reference is cleaned up by the corresponding vm_close - * (which should happen whether the vma was created by this call, or - * by a vm_open due to mremap or partial unmap or whatever). - */ - drm_gem_object_reference(obj); - - drm_vm_open_locked(dev, vma); + ret = drm_gem_mmap_obj(map->handle, map->size, vma);

out_unlock: mutex_unlock(&dev->struct_mutex); diff --git a/include/drm/drmP.h b/include/drm/drmP.h index b06f5af..79fb4c7 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1616,6 +1616,8 @@ int drm_gem_private_object_init(struct drm_device *dev, void drm_gem_object_handle_free(struct drm_gem_object *obj); void drm_gem_vm_open(struct vm_area_struct *vma); void drm_gem_vm_close(struct vm_area_struct *vma); +int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, + struct vm_area_struct *vma); int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma);

#include <drm/drm_global.h>

This allows creating a GEM CMA object without an associated DMA memory buffer, and will be used to implement DRM PRIME support.

Signed-off-by: Laurent Pinchart laurent.pinchart+renesas@ideasonboard.com Reviewed-by: Rob Clark robdclark@gmail.com --- drivers/gpu/drm/drm_gem_cma_helper.c | 83 +++++++++++++++++++++--------------- 1 file changed, 48 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 0a7e011..8cce330 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -32,62 +32,73 @@ static unsigned int get_gem_mmap_offset(struct drm_gem_object *obj) return (unsigned int)obj->map_list.hash.key << PAGE_SHIFT; }

-static void drm_gem_cma_buf_destroy(struct drm_device *drm, - struct drm_gem_cma_object *cma_obj) -{ - dma_free_writecombine(drm->dev, cma_obj->base.size, cma_obj->vaddr, - cma_obj->paddr); -} - /* - * drm_gem_cma_create - allocate an object with the given size + * __drm_gem_cma_create - Create a GEM CMA object without allocating memory + * @drm: The drm device + * @size: The GEM object size * - * returns a struct drm_gem_cma_object* on success or ERR_PTR values - * on failure. + * This function creates and initializes a GEM CMA object of the given size, but + * doesn't allocate any memory to back the object. + * + * Return a struct drm_gem_cma_object* on success or ERR_PTR values on failure. */ -struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm, - unsigned int size) +static struct drm_gem_cma_object * +__drm_gem_cma_create(struct drm_device *drm, unsigned int size) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *gem_obj; int ret;

- size = round_up(size, PAGE_SIZE); - cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL); if (!cma_obj) return ERR_PTR(-ENOMEM);

- cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size, - &cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN); - if (!cma_obj->vaddr) { - dev_err(drm->dev, "failed to allocate buffer with size %d\n", size); - ret = -ENOMEM; - goto err_dma_alloc; - } - gem_obj = &cma_obj->base;

ret = drm_gem_object_init(drm, gem_obj, size); if (ret) - goto err_obj_init; + goto error;

ret = drm_gem_create_mmap_offset(gem_obj); - if (ret) - goto err_create_mmap_offset; + if (ret) { + drm_gem_object_release(gem_obj); + goto error; + }

return cma_obj;

-err_create_mmap_offset: - drm_gem_object_release(gem_obj); +error: + kfree(cma_obj); + return ERR_PTR(ret); +}

-err_obj_init: - drm_gem_cma_buf_destroy(drm, cma_obj); +/* + * drm_gem_cma_create - allocate an object with the given size + * + * returns a struct drm_gem_cma_object* on success or ERR_PTR values + * on failure. + */ +struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm, + unsigned int size) +{ + struct drm_gem_cma_object *cma_obj;

-err_dma_alloc: - kfree(cma_obj); + size = round_up(size, PAGE_SIZE);

- return ERR_PTR(ret); + cma_obj = __drm_gem_cma_create(drm, size); + if (IS_ERR(cma_obj)) + return cma_obj; + + cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size, + &cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN); + 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); + } + + return cma_obj; } EXPORT_SYMBOL_GPL(drm_gem_cma_create);

@@ -143,11 +154,13 @@ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj) if (gem_obj->map_list.map) drm_gem_free_mmap_offset(gem_obj);

- drm_gem_object_release(gem_obj); - cma_obj = to_drm_gem_cma_obj(gem_obj);

- drm_gem_cma_buf_destroy(gem_obj->dev, cma_obj); + if (cma_obj->vaddr) + dma_free_writecombine(gem_obj->dev->dev, cma_obj->base.size, + cma_obj->vaddr, cma_obj->paddr); + + drm_gem_object_release(gem_obj);

kfree(cma_obj); }

Signed-off-by: Laurent Pinchart laurent.pinchart+renesas@ideasonboard.com --- drivers/gpu/drm/drm_gem_cma_helper.c | 317 ++++++++++++++++++++++++++++++++++- include/drm/drm_gem_cma_helper.h | 9 + 2 files changed, 323 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 7a4db4e..f94fcd7 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -21,6 +21,7 @@ #include <linux/slab.h> #include <linux/mutex.h> #include <linux/export.h> +#include <linux/dma-buf.h> #include <linux/dma-mapping.h>

#include <drm/drmP.h> @@ -82,6 +83,8 @@ 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 +97,29 @@ 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 +177,16 @@ 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);

@@ -291,3 +319,286 @@ void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj, struct seq_file *m } EXPORT_SYMBOL_GPL(drm_gem_cma_describe); #endif + +/* ----------------------------------------------------------------------------- + * DMA-BUF + */ + +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"); + sg_free_table(sgt); + sgt = ERR_PTR(-EIO); + goto done; + } + + cma_attach->dir = dir; + attach->priv = cma_attach; + + DRM_DEBUG_PRIME("buffer size = %zu\n", cma_obj->base.size); + +done: + 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) +{ + struct drm_gem_cma_object *cma_obj = dmabuf->priv; + struct drm_gem_object *gem_obj = &cma_obj->base; + int ret; + + ret = drm_gem_mmap_obj(gem_obj, gem_obj->size, vma); + if (ret < 0) + return ret; + + return drm_gem_cma_mmap_obj(cma_obj, vma); +} + +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); 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__ */