diff options
Diffstat (limited to 'drivers/gpu/drm/drm_gem_dma_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_gem_dma_helper.c | 602 |
1 files changed, 602 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_gem_dma_helper.c b/drivers/gpu/drm/drm_gem_dma_helper.c new file mode 100644 index 000000000000..f1780c01c928 --- /dev/null +++ b/drivers/gpu/drm/drm_gem_dma_helper.c @@ -0,0 +1,602 @@ +// 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->paddr, + DMA_TO_DEVICE, + GFP_KERNEL | __GFP_NOWARN); + } else { + dma_obj->vaddr = dma_alloc_wc(drm->dev, size, &dma_obj->paddr, + 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(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->paddr, + DMA_TO_DEVICE); + else + dma_free_wc(gem_obj->dev->dev, dma_obj->base.size, + dma_obj->vaddr, dma_obj->paddr); + } + + 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 paddr 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, "paddr=%pad\n", &dma_obj->paddr); + 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->paddr, 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->paddr = sg_dma_address(sgt->sgl); + dma_obj->sgt = sgt; + + DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &dma_obj->paddr, 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); + vma->vm_flags &= ~VM_PFNMAP; + vma->vm_flags |= VM_DONTEXPAND; + + 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->paddr, 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(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(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"); |