| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * drm gem DMA helper functions |
| * |
| * Copyright (C) 2012 Sascha Hauer, Pengutronix |
| * |
| * Based on Samsung Exynos code |
| * |
| * Copyright (c) 2011 Samsung Electronics Co., Ltd. |
| */ |
| |
| #include <linux/dma-buf.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/export.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/slab.h> |
| |
| #include <drm/drm.h> |
| #include <drm/drm_device.h> |
| #include <drm/drm_drv.h> |
| #include <drm/drm_gem_dma_helper.h> |
| #include <drm/drm_vma_manager.h> |
| |
| /** |
| * DOC: dma helpers |
| * |
| * The DRM GEM/DMA helpers are a means to provide buffer objects that are |
| * presented to the device as a contiguous chunk of memory. This is useful |
| * for devices that do not support scatter-gather DMA (either directly or |
| * by using an intimately attached IOMMU). |
| * |
| * For devices that access the memory bus through an (external) IOMMU then |
| * the buffer objects are allocated using a traditional page-based |
| * allocator and may be scattered through physical memory. However they |
| * are contiguous in the IOVA space so appear contiguous to devices using |
| * them. |
| * |
| * For other devices then the helpers rely on CMA to provide buffer |
| * objects that are physically contiguous in memory. |
| * |
| * For GEM callback helpers in struct &drm_gem_object functions, see likewise |
| * named functions with an _object_ infix (e.g., drm_gem_dma_object_vmap() wraps |
| * drm_gem_dma_vmap()). These helpers perform the necessary type conversion. |
| */ |
| |
| static const struct drm_gem_object_funcs drm_gem_dma_default_funcs = { |
| .free = drm_gem_dma_object_free, |
| .print_info = drm_gem_dma_object_print_info, |
| .get_sg_table = drm_gem_dma_object_get_sg_table, |
| .vmap = drm_gem_dma_object_vmap, |
| .mmap = drm_gem_dma_object_mmap, |
| .vm_ops = &drm_gem_dma_vm_ops, |
| }; |
| |
| /** |
| * __drm_gem_dma_create - Create a GEM DMA 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 DMA object of the given size, |
| * but doesn't allocate any memory to back the object. |
| * |
| * Returns: |
| * A struct drm_gem_dma_object * on success or an ERR_PTR()-encoded negative |
| * error code on failure. |
| */ |
| static struct drm_gem_dma_object * |
| __drm_gem_dma_create(struct drm_device *drm, size_t size, bool private) |
| { |
| struct drm_gem_dma_object *dma_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); |
| if (IS_ERR(gem_obj)) |
| return ERR_CAST(gem_obj); |
| dma_obj = to_drm_gem_dma_obj(gem_obj); |
| } else { |
| dma_obj = kzalloc(sizeof(*dma_obj), GFP_KERNEL); |
| if (!dma_obj) |
| return ERR_PTR(-ENOMEM); |
| gem_obj = &dma_obj->base; |
| } |
| |
| if (!gem_obj->funcs) |
| gem_obj->funcs = &drm_gem_dma_default_funcs; |
| |
| if (private) { |
| drm_gem_private_object_init(drm, gem_obj, size); |
| |
| /* Always use writecombine for dma-buf mappings */ |
| dma_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 dma_obj; |
| |
| error: |
| kfree(dma_obj); |
| return ERR_PTR(ret); |
| } |
| |
| /** |
| * drm_gem_dma_create - allocate an object with the given size |
| * @drm: DRM device |
| * @size: size of the object to allocate |
| * |
| * This function creates a DMA GEM object and allocates memory as backing store. |
| * The allocated memory will occupy a contiguous chunk of bus address space. |
| * |
| * For devices that are directly connected to the memory bus then the allocated |
| * memory will be physically contiguous. For devices that access through an |
| * IOMMU, then the allocated memory is not expected to be physically contiguous |
| * because having contiguous IOVAs is sufficient to meet a devices DMA |
| * requirements. |
| * |
| * Returns: |
| * A struct drm_gem_dma_object * on success or an ERR_PTR()-encoded negative |
| * error code on failure. |
| */ |
| struct drm_gem_dma_object *drm_gem_dma_create(struct drm_device *drm, |
| size_t size) |
| { |
| struct drm_gem_dma_object *dma_obj; |
| int ret; |
| |
| size = round_up(size, PAGE_SIZE); |
| |
| dma_obj = __drm_gem_dma_create(drm, size, false); |
| if (IS_ERR(dma_obj)) |
| return dma_obj; |
| |
| if (dma_obj->map_noncoherent) { |
| dma_obj->vaddr = dma_alloc_noncoherent(drm->dev, size, |
| &dma_obj->dma_addr, |
| DMA_TO_DEVICE, |
| GFP_KERNEL | __GFP_NOWARN); |
| } else { |
| dma_obj->vaddr = dma_alloc_wc(drm->dev, size, |
| &dma_obj->dma_addr, |
| GFP_KERNEL | __GFP_NOWARN); |
| } |
| if (!dma_obj->vaddr) { |
| drm_dbg(drm, "failed to allocate buffer with size %zu\n", |
| size); |
| ret = -ENOMEM; |
| goto error; |
| } |
| |
| return dma_obj; |
| |
| error: |
| drm_gem_object_put(&dma_obj->base); |
| return ERR_PTR(ret); |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_create); |
| |
| /** |
| * drm_gem_dma_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 DMA GEM object, allocating a 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. |
| * |
| * The allocated memory will occupy a contiguous chunk of bus address space. |
| * See drm_gem_dma_create() for more details. |
| * |
| * Returns: |
| * A struct drm_gem_dma_object * on success or an ERR_PTR()-encoded negative |
| * error code on failure. |
| */ |
| static struct drm_gem_dma_object * |
| drm_gem_dma_create_with_handle(struct drm_file *file_priv, |
| struct drm_device *drm, size_t size, |
| uint32_t *handle) |
| { |
| struct drm_gem_dma_object *dma_obj; |
| struct drm_gem_object *gem_obj; |
| int ret; |
| |
| dma_obj = drm_gem_dma_create(drm, size); |
| if (IS_ERR(dma_obj)) |
| return dma_obj; |
| |
| gem_obj = &dma_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 dma_obj; |
| } |
| |
| /** |
| * drm_gem_dma_free - free resources associated with a DMA GEM object |
| * @dma_obj: DMA GEM object to free |
| * |
| * This function frees the backing memory of the DMA 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. |
| */ |
| void drm_gem_dma_free(struct drm_gem_dma_object *dma_obj) |
| { |
| struct drm_gem_object *gem_obj = &dma_obj->base; |
| struct iosys_map map = IOSYS_MAP_INIT_VADDR(dma_obj->vaddr); |
| |
| if (gem_obj->import_attach) { |
| if (dma_obj->vaddr) |
| dma_buf_vunmap_unlocked(gem_obj->import_attach->dmabuf, &map); |
| drm_prime_gem_destroy(gem_obj, dma_obj->sgt); |
| } else if (dma_obj->vaddr) { |
| if (dma_obj->map_noncoherent) |
| dma_free_noncoherent(gem_obj->dev->dev, dma_obj->base.size, |
| dma_obj->vaddr, dma_obj->dma_addr, |
| DMA_TO_DEVICE); |
| else |
| dma_free_wc(gem_obj->dev->dev, dma_obj->base.size, |
| dma_obj->vaddr, dma_obj->dma_addr); |
| } |
| |
| drm_gem_object_release(gem_obj); |
| |
| kfree(dma_obj); |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_free); |
| |
| /** |
| * drm_gem_dma_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_dma_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_dma_object *dma_obj; |
| |
| if (args->pitch < min_pitch) |
| args->pitch = min_pitch; |
| |
| if (args->size < args->pitch * args->height) |
| args->size = args->pitch * args->height; |
| |
| dma_obj = drm_gem_dma_create_with_handle(file_priv, drm, args->size, |
| &args->handle); |
| return PTR_ERR_OR_ZERO(dma_obj); |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_dumb_create_internal); |
| |
| /** |
| * drm_gem_dma_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_dma_dumb_create_internal() function. |
| * |
| * Returns: |
| * 0 on success or a negative error code on failure. |
| */ |
| int drm_gem_dma_dumb_create(struct drm_file *file_priv, |
| struct drm_device *drm, |
| struct drm_mode_create_dumb *args) |
| { |
| struct drm_gem_dma_object *dma_obj; |
| |
| args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8); |
| args->size = args->pitch * args->height; |
| |
| dma_obj = drm_gem_dma_create_with_handle(file_priv, drm, args->size, |
| &args->handle); |
| return PTR_ERR_OR_ZERO(dma_obj); |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_dumb_create); |
| |
| const struct vm_operations_struct drm_gem_dma_vm_ops = { |
| .open = drm_gem_vm_open, |
| .close = drm_gem_vm_close, |
| }; |
| EXPORT_SYMBOL_GPL(drm_gem_dma_vm_ops); |
| |
| #ifndef CONFIG_MMU |
| /** |
| * drm_gem_dma_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_dma_get_unmapped_area(struct file *filp, |
| unsigned long addr, |
| unsigned long len, |
| unsigned long pgoff, |
| unsigned long flags) |
| { |
| struct drm_gem_dma_object *dma_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; |
| } |
| |
| dma_obj = to_drm_gem_dma_obj(obj); |
| |
| drm_gem_object_put(obj); |
| |
| return dma_obj->vaddr ? (unsigned long)dma_obj->vaddr : -EINVAL; |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_get_unmapped_area); |
| #endif |
| |
| /** |
| * drm_gem_dma_print_info() - Print &drm_gem_dma_object info for debugfs |
| * @dma_obj: DMA GEM object |
| * @p: DRM printer |
| * @indent: Tab indentation level |
| * |
| * This function prints dma_addr and vaddr for use in e.g. debugfs output. |
| */ |
| void drm_gem_dma_print_info(const struct drm_gem_dma_object *dma_obj, |
| struct drm_printer *p, unsigned int indent) |
| { |
| drm_printf_indent(p, indent, "dma_addr=%pad\n", &dma_obj->dma_addr); |
| drm_printf_indent(p, indent, "vaddr=%p\n", dma_obj->vaddr); |
| } |
| EXPORT_SYMBOL(drm_gem_dma_print_info); |
| |
| /** |
| * drm_gem_dma_get_sg_table - provide a scatter/gather table of pinned |
| * pages for a DMA GEM object |
| * @dma_obj: DMA GEM object |
| * |
| * This function exports a scatter/gather table by calling the standard |
| * DMA mapping API. |
| * |
| * Returns: |
| * A pointer to the scatter/gather table of pinned pages or NULL on failure. |
| */ |
| struct sg_table *drm_gem_dma_get_sg_table(struct drm_gem_dma_object *dma_obj) |
| { |
| struct drm_gem_object *obj = &dma_obj->base; |
| 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, dma_obj->vaddr, |
| dma_obj->dma_addr, obj->size); |
| if (ret < 0) |
| goto out; |
| |
| return sgt; |
| |
| out: |
| kfree(sgt); |
| return ERR_PTR(ret); |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_get_sg_table); |
| |
| /** |
| * drm_gem_dma_prime_import_sg_table - produce a DMA 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 DMA 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_dma_prime_import_sg_table(struct drm_device *dev, |
| struct dma_buf_attachment *attach, |
| struct sg_table *sgt) |
| { |
| struct drm_gem_dma_object *dma_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 DMA GEM buffer. */ |
| dma_obj = __drm_gem_dma_create(dev, attach->dmabuf->size, true); |
| if (IS_ERR(dma_obj)) |
| return ERR_CAST(dma_obj); |
| |
| dma_obj->dma_addr = sg_dma_address(sgt->sgl); |
| dma_obj->sgt = sgt; |
| |
| drm_dbg_prime(dev, "dma_addr = %pad, size = %zu\n", &dma_obj->dma_addr, |
| attach->dmabuf->size); |
| |
| return &dma_obj->base; |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_prime_import_sg_table); |
| |
| /** |
| * drm_gem_dma_vmap - map a DMA GEM object into the kernel's virtual |
| * address space |
| * @dma_obj: DMA GEM object |
| * @map: Returns the kernel virtual address of the DMA GEM object's backing |
| * store. |
| * |
| * This function maps a buffer into the kernel's virtual address space. |
| * Since the DMA buffers are already mapped into the kernel virtual address |
| * space this simply returns the cached virtual address. |
| * |
| * Returns: |
| * 0 on success, or a negative error code otherwise. |
| */ |
| int drm_gem_dma_vmap(struct drm_gem_dma_object *dma_obj, |
| struct iosys_map *map) |
| { |
| iosys_map_set_vaddr(map, dma_obj->vaddr); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_vmap); |
| |
| /** |
| * drm_gem_dma_mmap - memory-map an exported DMA GEM object |
| * @dma_obj: DMA 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. |
| * |
| * Returns: |
| * 0 on success or a negative error code on failure. |
| */ |
| int drm_gem_dma_mmap(struct drm_gem_dma_object *dma_obj, struct vm_area_struct *vma) |
| { |
| struct drm_gem_object *obj = &dma_obj->base; |
| 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); |
| vm_flags_mod(vma, VM_DONTEXPAND, VM_PFNMAP); |
| |
| if (dma_obj->map_noncoherent) { |
| vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
| |
| ret = dma_mmap_pages(dma_obj->base.dev->dev, |
| vma, vma->vm_end - vma->vm_start, |
| virt_to_page(dma_obj->vaddr)); |
| } else { |
| ret = dma_mmap_wc(dma_obj->base.dev->dev, vma, dma_obj->vaddr, |
| dma_obj->dma_addr, |
| vma->vm_end - vma->vm_start); |
| } |
| if (ret) |
| drm_gem_vm_close(vma); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(drm_gem_dma_mmap); |
| |
| /** |
| * drm_gem_dma_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_dma_prime_import_sg_table() and uses dma_buf_vmap() to get the kernel |
| * virtual address. This ensures that a DMA 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_DMA_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_dma_prime_import_sg_table_vmap(struct drm_device *dev, |
| struct dma_buf_attachment *attach, |
| struct sg_table *sgt) |
| { |
| struct drm_gem_dma_object *dma_obj; |
| struct drm_gem_object *obj; |
| struct iosys_map map; |
| int ret; |
| |
| ret = dma_buf_vmap_unlocked(attach->dmabuf, &map); |
| if (ret) { |
| DRM_ERROR("Failed to vmap PRIME buffer\n"); |
| return ERR_PTR(ret); |
| } |
| |
| obj = drm_gem_dma_prime_import_sg_table(dev, attach, sgt); |
| if (IS_ERR(obj)) { |
| dma_buf_vunmap_unlocked(attach->dmabuf, &map); |
| return obj; |
| } |
| |
| dma_obj = to_drm_gem_dma_obj(obj); |
| dma_obj->vaddr = map.vaddr; |
| |
| return obj; |
| } |
| EXPORT_SYMBOL(drm_gem_dma_prime_import_sg_table_vmap); |
| |
| MODULE_DESCRIPTION("DRM DMA memory-management helpers"); |
| MODULE_IMPORT_NS(DMA_BUF); |
| MODULE_LICENSE("GPL"); |