// SPDX-License-Identifier: GPL-2.0-or-later /* * drm gem CMA (contiguous memory allocator) helper functions * * Copyright (C) 2012 Sascha Hauer, Pengutronix * * Based on Samsung Exynos code * * Copyright (c) 2011 Samsung Electronics Co., Ltd. */ #include #include #include #include #include #include #include #include #include #include #include /** * DOC: cma helpers * * The Contiguous Memory Allocator reserves a pool of memory at early boot * that is used to service requests for large blocks of contiguous memory. * * The DRM GEM/CMA helpers use this allocator as a means to provide buffer * objects that are physically contiguous in memory. This is useful for * display drivers that are unable to map scattered buffers via an IOMMU. */ static const struct drm_gem_object_funcs drm_gem_cma_default_funcs = { .free = drm_gem_cma_free_object, .print_info = drm_gem_cma_print_info, .get_sg_table = drm_gem_cma_get_sg_table, .vmap = drm_gem_cma_vmap, .mmap = drm_gem_cma_mmap, .vm_ops = &drm_gem_cma_vm_ops, }; /** * __drm_gem_cma_create - Create a GEM CMA object without allocating memory * @drm: DRM device * @size: size of the object to allocate * @private: true if used for internal purposes * * This function creates and initializes a GEM CMA object of the given size, * but doesn't allocate any memory to back the object. * * Returns: * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative * error code on failure. */ static struct drm_gem_cma_object * __drm_gem_cma_create(struct drm_device *drm, size_t size, bool private) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *gem_obj; int ret = 0; if (drm->driver->gem_create_object) gem_obj = drm->driver->gem_create_object(drm, size); else gem_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL); if (!gem_obj) return ERR_PTR(-ENOMEM); if (!gem_obj->funcs) gem_obj->funcs = &drm_gem_cma_default_funcs; cma_obj = container_of(gem_obj, struct drm_gem_cma_object, base); if (private) { drm_gem_private_object_init(drm, gem_obj, size); /* Always use writecombine for dma-buf mappings */ cma_obj->map_noncoherent = false; } else { ret = drm_gem_object_init(drm, gem_obj, size); } if (ret) goto error; ret = drm_gem_create_mmap_offset(gem_obj); if (ret) { drm_gem_object_release(gem_obj); goto error; } return cma_obj; error: kfree(cma_obj); return ERR_PTR(ret); } /** * drm_gem_cma_create - allocate an object with the given size * @drm: DRM device * @size: size of the object to allocate * * This function creates a CMA GEM object and allocates a contiguous chunk of * memory as backing store. * * Returns: * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative * error code on failure. */ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm, size_t size) { struct drm_gem_cma_object *cma_obj; int ret; size = round_up(size, PAGE_SIZE); cma_obj = __drm_gem_cma_create(drm, size, false); if (IS_ERR(cma_obj)) return cma_obj; if (cma_obj->map_noncoherent) { cma_obj->vaddr = dma_alloc_noncoherent(drm->dev, size, &cma_obj->paddr, DMA_TO_DEVICE, GFP_KERNEL | __GFP_NOWARN); } else { cma_obj->vaddr = dma_alloc_wc(drm->dev, size, &cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN); } if (!cma_obj->vaddr) { drm_dbg(drm, "failed to allocate buffer with size %zu\n", size); ret = -ENOMEM; goto error; } return cma_obj; error: drm_gem_object_put(&cma_obj->base); return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(drm_gem_cma_create); /** * drm_gem_cma_create_with_handle - allocate an object with the given size and * return a GEM handle to it * @file_priv: DRM file-private structure to register the handle for * @drm: DRM device * @size: size of the object to allocate * @handle: return location for the GEM handle * * This function creates a CMA GEM object, allocating a physically contiguous * chunk of memory as backing store. The GEM object is then added to the list * of object associated with the given file and a handle to it is returned. * * Returns: * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative * error code on failure. */ static struct drm_gem_cma_object * drm_gem_cma_create_with_handle(struct drm_file *file_priv, struct drm_device *drm, size_t size, uint32_t *handle) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *gem_obj; int ret; cma_obj = drm_gem_cma_create(drm, size); if (IS_ERR(cma_obj)) return cma_obj; gem_obj = &cma_obj->base; /* * allocate a id of idr table where the obj is registered * and handle has the id what user can see. */ ret = drm_gem_handle_create(file_priv, gem_obj, handle); /* drop reference from allocate - handle holds it now. */ drm_gem_object_put(gem_obj); if (ret) return ERR_PTR(ret); return cma_obj; } /** * drm_gem_cma_free_object - free resources associated with a CMA GEM object * @gem_obj: GEM object to free * * This function frees the backing memory of the CMA GEM object, cleans up the * GEM object state and frees the memory used to store the object itself. * If the buffer is imported and the virtual address is set, it is released. * Drivers using the CMA helpers should set this as their * &drm_gem_object_funcs.free callback. */ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj) { struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(gem_obj); struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(cma_obj->vaddr); if (gem_obj->import_attach) { if (cma_obj->vaddr) dma_buf_vunmap(gem_obj->import_attach->dmabuf, &map); drm_prime_gem_destroy(gem_obj, cma_obj->sgt); } else if (cma_obj->vaddr) { if (cma_obj->map_noncoherent) dma_free_noncoherent(gem_obj->dev->dev, cma_obj->base.size, cma_obj->vaddr, cma_obj->paddr, DMA_TO_DEVICE); else dma_free_wc(gem_obj->dev->dev, cma_obj->base.size, cma_obj->vaddr, cma_obj->paddr); } drm_gem_object_release(gem_obj); kfree(cma_obj); } EXPORT_SYMBOL_GPL(drm_gem_cma_free_object); /** * drm_gem_cma_dumb_create_internal - create a dumb buffer object * @file_priv: DRM file-private structure to create the dumb buffer for * @drm: DRM device * @args: IOCTL data * * This aligns the pitch and size arguments to the minimum required. This is * an internal helper that can be wrapped by a driver to account for hardware * with more specific alignment requirements. It should not be used directly * as their &drm_driver.dumb_create callback. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv, struct drm_device *drm, struct drm_mode_create_dumb *args) { unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8); struct drm_gem_cma_object *cma_obj; if (args->pitch < min_pitch) args->pitch = min_pitch; if (args->size < args->pitch * args->height) args->size = args->pitch * args->height; cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size, &args->handle); return PTR_ERR_OR_ZERO(cma_obj); } EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal); /** * drm_gem_cma_dumb_create - create a dumb buffer object * @file_priv: DRM file-private structure to create the dumb buffer for * @drm: DRM device * @args: IOCTL data * * This function computes the pitch of the dumb buffer and rounds it up to an * integer number of bytes per pixel. Drivers for hardware that doesn't have * any additional restrictions on the pitch can directly use this function as * their &drm_driver.dumb_create callback. * * For hardware with additional restrictions, drivers can adjust the fields * set up by userspace and pass the IOCTL data along to the * drm_gem_cma_dumb_create_internal() function. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_cma_dumb_create(struct drm_file *file_priv, struct drm_device *drm, struct drm_mode_create_dumb *args) { struct drm_gem_cma_object *cma_obj; args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8); args->size = args->pitch * args->height; cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size, &args->handle); return PTR_ERR_OR_ZERO(cma_obj); } EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create); const struct vm_operations_struct drm_gem_cma_vm_ops = { .open = drm_gem_vm_open, .close = drm_gem_vm_close, }; EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops); #ifndef CONFIG_MMU /** * drm_gem_cma_get_unmapped_area - propose address for mapping in noMMU cases * @filp: file object * @addr: memory address * @len: buffer size * @pgoff: page offset * @flags: memory flags * * This function is used in noMMU platforms to propose address mapping * for a given buffer. * It's intended to be used as a direct handler for the struct * &file_operations.get_unmapped_area operation. * * Returns: * mapping address on success or a negative error code on failure. */ unsigned long drm_gem_cma_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *obj = NULL; struct drm_file *priv = filp->private_data; struct drm_device *dev = priv->minor->dev; struct drm_vma_offset_node *node; if (drm_dev_is_unplugged(dev)) return -ENODEV; drm_vma_offset_lock_lookup(dev->vma_offset_manager); node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager, pgoff, len >> PAGE_SHIFT); if (likely(node)) { obj = container_of(node, struct drm_gem_object, vma_node); /* * When the object is being freed, after it hits 0-refcnt it * proceeds to tear down the object. In the process it will * attempt to remove the VMA offset and so acquire this * mgr->vm_lock. Therefore if we find an object with a 0-refcnt * that matches our range, we know it is in the process of being * destroyed and will be freed as soon as we release the lock - * so we have to check for the 0-refcnted object and treat it as * invalid. */ if (!kref_get_unless_zero(&obj->refcount)) obj = NULL; } drm_vma_offset_unlock_lookup(dev->vma_offset_manager); if (!obj) return -EINVAL; if (!drm_vma_node_is_allowed(node, priv)) { drm_gem_object_put(obj); return -EACCES; } cma_obj = to_drm_gem_cma_obj(obj); drm_gem_object_put(obj); return cma_obj->vaddr ? (unsigned long)cma_obj->vaddr : -EINVAL; } EXPORT_SYMBOL_GPL(drm_gem_cma_get_unmapped_area); #endif /** * drm_gem_cma_print_info() - Print &drm_gem_cma_object info for debugfs * @p: DRM printer * @indent: Tab indentation level * @obj: GEM object * * This function can be used as the &drm_driver->gem_print_info callback. * It prints paddr and vaddr for use in e.g. debugfs output. */ void drm_gem_cma_print_info(struct drm_printer *p, unsigned int indent, const struct drm_gem_object *obj) { const struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj); drm_printf_indent(p, indent, "paddr=%pad\n", &cma_obj->paddr); drm_printf_indent(p, indent, "vaddr=%p\n", cma_obj->vaddr); } EXPORT_SYMBOL(drm_gem_cma_print_info); /** * drm_gem_cma_get_sg_table - provide a scatter/gather table of pinned * pages for a CMA GEM object * @obj: GEM object * * This function exports a scatter/gather table by * calling the standard DMA mapping API. Drivers using the CMA helpers should * set this as their &drm_gem_object_funcs.get_sg_table callback. * * Returns: * A pointer to the scatter/gather table of pinned pages or NULL on failure. */ struct sg_table *drm_gem_cma_get_sg_table(struct drm_gem_object *obj) { struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj); struct sg_table *sgt; int ret; sgt = kzalloc(sizeof(*sgt), GFP_KERNEL); if (!sgt) return ERR_PTR(-ENOMEM); ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr, cma_obj->paddr, obj->size); if (ret < 0) goto out; return sgt; out: kfree(sgt); return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(drm_gem_cma_get_sg_table); /** * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another * driver's scatter/gather table of pinned pages * @dev: device to import into * @attach: DMA-BUF attachment * @sgt: scatter/gather table of pinned pages * * This function imports a scatter/gather table exported via DMA-BUF by * another driver. Imported buffers must be physically contiguous in memory * (i.e. the scatter/gather table must contain a single entry). Drivers that * use the CMA helpers should set this as their * &drm_driver.gem_prime_import_sg_table callback. * * Returns: * A pointer to a newly created GEM object or an ERR_PTR-encoded negative * error code on failure. */ struct drm_gem_object * drm_gem_cma_prime_import_sg_table(struct drm_device *dev, struct dma_buf_attachment *attach, struct sg_table *sgt) { struct drm_gem_cma_object *cma_obj; /* check if the entries in the sg_table are contiguous */ if (drm_prime_get_contiguous_size(sgt) < attach->dmabuf->size) return ERR_PTR(-EINVAL); /* Create a CMA GEM buffer. */ cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size, true); if (IS_ERR(cma_obj)) return ERR_CAST(cma_obj); cma_obj->paddr = sg_dma_address(sgt->sgl); cma_obj->sgt = sgt; DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size); return &cma_obj->base; } EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table); /** * drm_gem_cma_vmap - map a CMA GEM object into the kernel's virtual * address space * @obj: GEM object * @map: Returns the kernel virtual address of the CMA GEM object's backing * store. * * This function maps a buffer into the kernel's * virtual address space. Since the CMA buffers are already mapped into the * kernel virtual address space this simply returns the cached virtual * address. Drivers using the CMA helpers should set this as their DRM * driver's &drm_gem_object_funcs.vmap callback. * * Returns: * 0 on success, or a negative error code otherwise. */ int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map *map) { struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj); dma_buf_map_set_vaddr(map, cma_obj->vaddr); return 0; } EXPORT_SYMBOL_GPL(drm_gem_cma_vmap); /** * drm_gem_cma_mmap - memory-map an exported CMA GEM object * @obj: GEM object * @vma: VMA for the area to be mapped * * This function maps a buffer into a userspace process's address space. * In addition to the usual GEM VMA setup it immediately faults in the entire * object instead of using on-demand faulting. Drivers that use the CMA * helpers should set this as their &drm_gem_object_funcs.mmap callback. * * Returns: * 0 on success or a negative error code on failure. */ int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma) { struct drm_gem_cma_object *cma_obj; int ret; /* * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map * the whole buffer. */ vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node); vma->vm_flags &= ~VM_PFNMAP; vma->vm_flags |= VM_DONTEXPAND; cma_obj = to_drm_gem_cma_obj(obj); if (cma_obj->map_noncoherent) { vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); ret = dma_mmap_pages(cma_obj->base.dev->dev, vma, vma->vm_end - vma->vm_start, virt_to_page(cma_obj->vaddr)); } else { ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr, cma_obj->paddr, vma->vm_end - vma->vm_start); } if (ret) drm_gem_vm_close(vma); return ret; } EXPORT_SYMBOL_GPL(drm_gem_cma_mmap); /** * drm_gem_cma_prime_import_sg_table_vmap - PRIME import another driver's * scatter/gather table and get the virtual address of the buffer * @dev: DRM device * @attach: DMA-BUF attachment * @sgt: Scatter/gather table of pinned pages * * This function imports a scatter/gather table using * drm_gem_cma_prime_import_sg_table() and uses dma_buf_vmap() to get the kernel * virtual address. This ensures that a CMA GEM object always has its virtual * address set. This address is released when the object is freed. * * This function can be used as the &drm_driver.gem_prime_import_sg_table * callback. The &DRM_GEM_CMA_DRIVER_OPS_VMAP macro provides a shortcut to set * the necessary DRM driver operations. * * Returns: * A pointer to a newly created GEM object or an ERR_PTR-encoded negative * error code on failure. */ struct drm_gem_object * drm_gem_cma_prime_import_sg_table_vmap(struct drm_device *dev, struct dma_buf_attachment *attach, struct sg_table *sgt) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *obj; struct dma_buf_map map; int ret; ret = dma_buf_vmap(attach->dmabuf, &map); if (ret) { DRM_ERROR("Failed to vmap PRIME buffer\n"); return ERR_PTR(ret); } obj = drm_gem_cma_prime_import_sg_table(dev, attach, sgt); if (IS_ERR(obj)) { dma_buf_vunmap(attach->dmabuf, &map); return obj; } cma_obj = to_drm_gem_cma_obj(obj); cma_obj->vaddr = map.vaddr; return obj; } EXPORT_SYMBOL(drm_gem_cma_prime_import_sg_table_vmap);