diff options
Diffstat (limited to 'drivers/gpu/drm/drm_gem_shmem_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_gem_shmem_helper.c | 898 |
1 files changed, 898 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c new file mode 100644 index 000000000000..dc94a27710e5 --- /dev/null +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -0,0 +1,898 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2018 Noralf Trønnes + */ + +#include <linux/dma-buf.h> +#include <linux/export.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/shmem_fs.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> + +#ifdef CONFIG_X86 +#include <asm/set_memory.h> +#endif + +#include <drm/drm.h> +#include <drm/drm_device.h> +#include <drm/drm_drv.h> +#include <drm/drm_dumb_buffers.h> +#include <drm/drm_gem_shmem_helper.h> +#include <drm/drm_prime.h> +#include <drm/drm_print.h> + +MODULE_IMPORT_NS("DMA_BUF"); + +/** + * DOC: overview + * + * This library provides helpers for GEM objects backed by shmem buffers + * allocated using anonymous pageable memory. + * + * Functions that operate on the GEM object receive struct &drm_gem_shmem_object. + * For GEM callback helpers in struct &drm_gem_object functions, see likewise + * named functions with an _object_ infix (e.g., drm_gem_shmem_object_vmap() wraps + * drm_gem_shmem_vmap()). These helpers perform the necessary type conversion. + */ + +static const struct drm_gem_object_funcs drm_gem_shmem_funcs = { + .free = drm_gem_shmem_object_free, + .print_info = drm_gem_shmem_object_print_info, + .pin = drm_gem_shmem_object_pin, + .unpin = drm_gem_shmem_object_unpin, + .get_sg_table = drm_gem_shmem_object_get_sg_table, + .vmap = drm_gem_shmem_object_vmap, + .vunmap = drm_gem_shmem_object_vunmap, + .mmap = drm_gem_shmem_object_mmap, + .vm_ops = &drm_gem_shmem_vm_ops, +}; + +static int __drm_gem_shmem_init(struct drm_device *dev, struct drm_gem_shmem_object *shmem, + size_t size, bool private, struct vfsmount *gemfs) +{ + struct drm_gem_object *obj = &shmem->base; + int ret = 0; + + if (!obj->funcs) + obj->funcs = &drm_gem_shmem_funcs; + + if (private) { + drm_gem_private_object_init(dev, obj, size); + shmem->map_wc = false; /* dma-buf mappings use always writecombine */ + } else { + ret = drm_gem_object_init_with_mnt(dev, obj, size, gemfs); + } + if (ret) { + drm_gem_private_object_fini(obj); + return ret; + } + + ret = drm_gem_create_mmap_offset(obj); + if (ret) + goto err_release; + + INIT_LIST_HEAD(&shmem->madv_list); + + if (!private) { + /* + * Our buffers are kept pinned, so allocating them + * from the MOVABLE zone is a really bad idea, and + * conflicts with CMA. See comments above new_inode() + * why this is required _and_ expected if you're + * going to pin these pages. + */ + mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER | + __GFP_RETRY_MAYFAIL | __GFP_NOWARN); + } + + return 0; +err_release: + drm_gem_object_release(obj); + return ret; +} + +/** + * drm_gem_shmem_init - Initialize an allocated object. + * @dev: DRM device + * @obj: The allocated shmem GEM object. + * + * Returns: + * 0 on success, or a negative error code on failure. + */ +int drm_gem_shmem_init(struct drm_device *dev, struct drm_gem_shmem_object *shmem, size_t size) +{ + return __drm_gem_shmem_init(dev, shmem, size, false, NULL); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_init); + +static struct drm_gem_shmem_object * +__drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private, + struct vfsmount *gemfs) +{ + struct drm_gem_shmem_object *shmem; + struct drm_gem_object *obj; + int ret = 0; + + size = PAGE_ALIGN(size); + + if (dev->driver->gem_create_object) { + obj = dev->driver->gem_create_object(dev, size); + if (IS_ERR(obj)) + return ERR_CAST(obj); + shmem = to_drm_gem_shmem_obj(obj); + } else { + shmem = kzalloc(sizeof(*shmem), GFP_KERNEL); + if (!shmem) + return ERR_PTR(-ENOMEM); + obj = &shmem->base; + } + + ret = __drm_gem_shmem_init(dev, shmem, size, private, gemfs); + if (ret) { + kfree(obj); + return ERR_PTR(ret); + } + + return shmem; +} +/** + * drm_gem_shmem_create - Allocate an object with the given size + * @dev: DRM device + * @size: Size of the object to allocate + * + * This function creates a shmem GEM object. + * + * Returns: + * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative + * error code on failure. + */ +struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size) +{ + return __drm_gem_shmem_create(dev, size, false, NULL); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_create); + +/** + * drm_gem_shmem_create_with_mnt - Allocate an object with the given size in a + * given mountpoint + * @dev: DRM device + * @size: Size of the object to allocate + * @gemfs: tmpfs mount where the GEM object will be created + * + * This function creates a shmem GEM object in a given tmpfs mountpoint. + * + * Returns: + * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative + * error code on failure. + */ +struct drm_gem_shmem_object *drm_gem_shmem_create_with_mnt(struct drm_device *dev, + size_t size, + struct vfsmount *gemfs) +{ + return __drm_gem_shmem_create(dev, size, false, gemfs); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_create_with_mnt); + +/** + * drm_gem_shmem_release - Release resources associated with a shmem GEM object. + * @shmem: shmem GEM object + * + * This function cleans up the GEM object state, but does not free the memory used to store the + * object itself. This function is meant to be a dedicated helper for the Rust GEM bindings. + */ +void drm_gem_shmem_release(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + + if (drm_gem_is_imported(obj)) { + drm_prime_gem_destroy(obj, shmem->sgt); + } else { + dma_resv_lock(shmem->base.resv, NULL); + + drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count)); + + if (shmem->sgt) { + dma_unmap_sgtable(obj->dev->dev, shmem->sgt, + DMA_BIDIRECTIONAL, 0); + sg_free_table(shmem->sgt); + kfree(shmem->sgt); + } + if (shmem->pages) + drm_gem_shmem_put_pages_locked(shmem); + + drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count)); + drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count)); + + dma_resv_unlock(shmem->base.resv); + } + + drm_gem_object_release(obj); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_release); + +/** + * drm_gem_shmem_free - Free resources associated with a shmem GEM object + * @shmem: shmem GEM object to free + * + * This function cleans up the GEM object state and frees the memory used to + * store the object itself. + */ +void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) +{ + drm_gem_shmem_release(shmem); + kfree(shmem); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_free); + +static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + struct page **pages; + + dma_resv_assert_held(shmem->base.resv); + + if (refcount_inc_not_zero(&shmem->pages_use_count)) + return 0; + + pages = drm_gem_get_pages(obj); + if (IS_ERR(pages)) { + drm_dbg_kms(obj->dev, "Failed to get pages (%ld)\n", + PTR_ERR(pages)); + return PTR_ERR(pages); + } + + /* + * TODO: Allocating WC pages which are correctly flushed is only + * supported on x86. Ideal solution would be a GFP_WC flag, which also + * ttm_pool.c could use. + */ +#ifdef CONFIG_X86 + if (shmem->map_wc) + set_pages_array_wc(pages, obj->size >> PAGE_SHIFT); +#endif + + shmem->pages = pages; + + refcount_set(&shmem->pages_use_count, 1); + + return 0; +} + +/* + * drm_gem_shmem_put_pages_locked - Decrease use count on the backing pages for a shmem GEM object + * @shmem: shmem GEM object + * + * This function decreases the use count and puts the backing pages when use drops to zero. + */ +void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + + dma_resv_assert_held(shmem->base.resv); + + if (refcount_dec_and_test(&shmem->pages_use_count)) { +#ifdef CONFIG_X86 + if (shmem->map_wc) + set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT); +#endif + + drm_gem_put_pages(obj, shmem->pages, + shmem->pages_mark_dirty_on_put, + shmem->pages_mark_accessed_on_put); + shmem->pages = NULL; + } +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_put_pages_locked); + +int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem) +{ + int ret; + + dma_resv_assert_held(shmem->base.resv); + + drm_WARN_ON(shmem->base.dev, drm_gem_is_imported(&shmem->base)); + + if (refcount_inc_not_zero(&shmem->pages_pin_count)) + return 0; + + ret = drm_gem_shmem_get_pages_locked(shmem); + if (!ret) + refcount_set(&shmem->pages_pin_count, 1); + + return ret; +} +EXPORT_SYMBOL(drm_gem_shmem_pin_locked); + +void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem) +{ + dma_resv_assert_held(shmem->base.resv); + + if (refcount_dec_and_test(&shmem->pages_pin_count)) + drm_gem_shmem_put_pages_locked(shmem); +} +EXPORT_SYMBOL(drm_gem_shmem_unpin_locked); + +/** + * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object + * @shmem: shmem GEM object + * + * This function makes sure the backing pages are pinned in memory while the + * buffer is exported. + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + int ret; + + drm_WARN_ON(obj->dev, drm_gem_is_imported(obj)); + + if (refcount_inc_not_zero(&shmem->pages_pin_count)) + return 0; + + ret = dma_resv_lock_interruptible(shmem->base.resv, NULL); + if (ret) + return ret; + ret = drm_gem_shmem_pin_locked(shmem); + dma_resv_unlock(shmem->base.resv); + + return ret; +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_pin); + +/** + * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object + * @shmem: shmem GEM object + * + * This function removes the requirement that the backing pages are pinned in + * memory. + */ +void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + + drm_WARN_ON(obj->dev, drm_gem_is_imported(obj)); + + if (refcount_dec_not_one(&shmem->pages_pin_count)) + return; + + dma_resv_lock(shmem->base.resv, NULL); + drm_gem_shmem_unpin_locked(shmem); + dma_resv_unlock(shmem->base.resv); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_unpin); + +/* + * drm_gem_shmem_vmap_locked - Create a virtual mapping for a shmem GEM object + * @shmem: shmem GEM object + * @map: Returns the kernel virtual address of the SHMEM GEM object's backing + * store. + * + * This function makes sure that a contiguous kernel virtual address mapping + * exists for the buffer backing the shmem GEM object. It hides the differences + * between dma-buf imported and natively allocated objects. + * + * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap_locked(). + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, + struct iosys_map *map) +{ + struct drm_gem_object *obj = &shmem->base; + int ret = 0; + + dma_resv_assert_held(obj->resv); + + if (drm_gem_is_imported(obj)) { + ret = dma_buf_vmap(obj->import_attach->dmabuf, map); + } else { + pgprot_t prot = PAGE_KERNEL; + + dma_resv_assert_held(shmem->base.resv); + + if (refcount_inc_not_zero(&shmem->vmap_use_count)) { + iosys_map_set_vaddr(map, shmem->vaddr); + return 0; + } + + ret = drm_gem_shmem_pin_locked(shmem); + if (ret) + return ret; + + if (shmem->map_wc) + prot = pgprot_writecombine(prot); + shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT, + VM_MAP, prot); + if (!shmem->vaddr) { + ret = -ENOMEM; + } else { + iosys_map_set_vaddr(map, shmem->vaddr); + refcount_set(&shmem->vmap_use_count, 1); + } + } + + if (ret) { + drm_dbg_kms(obj->dev, "Failed to vmap pages, error %d\n", ret); + goto err_put_pages; + } + + return 0; + +err_put_pages: + if (!drm_gem_is_imported(obj)) + drm_gem_shmem_unpin_locked(shmem); + + return ret; +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_vmap_locked); + +/* + * drm_gem_shmem_vunmap_locked - Unmap a virtual mapping for a shmem GEM object + * @shmem: shmem GEM object + * @map: Kernel virtual address where the SHMEM GEM object was mapped + * + * This function cleans up a kernel virtual address mapping acquired by + * drm_gem_shmem_vmap_locked(). The mapping is only removed when the use count + * drops to zero. + * + * This function hides the differences between dma-buf imported and natively + * allocated objects. + */ +void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, + struct iosys_map *map) +{ + struct drm_gem_object *obj = &shmem->base; + + dma_resv_assert_held(obj->resv); + + if (drm_gem_is_imported(obj)) { + dma_buf_vunmap(obj->import_attach->dmabuf, map); + } else { + dma_resv_assert_held(shmem->base.resv); + + if (refcount_dec_and_test(&shmem->vmap_use_count)) { + vunmap(shmem->vaddr); + shmem->vaddr = NULL; + + drm_gem_shmem_unpin_locked(shmem); + } + } +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_vunmap_locked); + +static int +drm_gem_shmem_create_with_handle(struct drm_file *file_priv, + struct drm_device *dev, size_t size, + uint32_t *handle) +{ + struct drm_gem_shmem_object *shmem; + int ret; + + shmem = drm_gem_shmem_create(dev, size); + if (IS_ERR(shmem)) + return PTR_ERR(shmem); + + /* + * Allocate an 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, &shmem->base, handle); + /* drop reference from allocate - handle holds it now. */ + drm_gem_object_put(&shmem->base); + + return ret; +} + +/* Update madvise status, returns true if not purged, else + * false or -errno. + */ +int drm_gem_shmem_madvise_locked(struct drm_gem_shmem_object *shmem, int madv) +{ + dma_resv_assert_held(shmem->base.resv); + + if (shmem->madv >= 0) + shmem->madv = madv; + + madv = shmem->madv; + + return (madv >= 0); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_madvise_locked); + +void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + struct drm_device *dev = obj->dev; + + dma_resv_assert_held(shmem->base.resv); + + drm_WARN_ON(obj->dev, !drm_gem_shmem_is_purgeable(shmem)); + + dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0); + sg_free_table(shmem->sgt); + kfree(shmem->sgt); + shmem->sgt = NULL; + + drm_gem_shmem_put_pages_locked(shmem); + + shmem->madv = -1; + + drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping); + drm_gem_free_mmap_offset(obj); + + /* Our goal here is to return as much of the memory as + * is possible back to the system as we are called from OOM. + * To do this we must instruct the shmfs to drop all of its + * backing pages, *now*. + */ + shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1); + + invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_purge_locked); + +/** + * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object + * @file: DRM file structure to create the dumb buffer for + * @dev: 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 before calling into this function. + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev, + struct drm_mode_create_dumb *args) +{ + int ret; + + ret = drm_mode_size_dumb(dev, args, SZ_8, 0); + if (ret) + return ret; + + return drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create); + +static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) +{ + struct vm_area_struct *vma = vmf->vma; + struct drm_gem_object *obj = vma->vm_private_data; + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + loff_t num_pages = obj->size >> PAGE_SHIFT; + vm_fault_t ret; + struct page *page; + pgoff_t page_offset; + + /* We don't use vmf->pgoff since that has the fake offset */ + page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT; + + dma_resv_lock(shmem->base.resv, NULL); + + if (page_offset >= num_pages || + drm_WARN_ON_ONCE(obj->dev, !shmem->pages) || + shmem->madv < 0) { + ret = VM_FAULT_SIGBUS; + } else { + page = shmem->pages[page_offset]; + + ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page)); + } + + dma_resv_unlock(shmem->base.resv); + + return ret; +} + +static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) +{ + struct drm_gem_object *obj = vma->vm_private_data; + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + + drm_WARN_ON(obj->dev, drm_gem_is_imported(obj)); + + dma_resv_lock(shmem->base.resv, NULL); + + /* + * We should have already pinned the pages when the buffer was first + * mmap'd, vm_open() just grabs an additional reference for the new + * mm the vma is getting copied into (ie. on fork()). + */ + drm_WARN_ON_ONCE(obj->dev, + !refcount_inc_not_zero(&shmem->pages_use_count)); + + dma_resv_unlock(shmem->base.resv); + + drm_gem_vm_open(vma); +} + +static void drm_gem_shmem_vm_close(struct vm_area_struct *vma) +{ + struct drm_gem_object *obj = vma->vm_private_data; + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + + dma_resv_lock(shmem->base.resv, NULL); + drm_gem_shmem_put_pages_locked(shmem); + dma_resv_unlock(shmem->base.resv); + + drm_gem_vm_close(vma); +} + +const struct vm_operations_struct drm_gem_shmem_vm_ops = { + .fault = drm_gem_shmem_fault, + .open = drm_gem_shmem_vm_open, + .close = drm_gem_shmem_vm_close, +}; +EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops); + +/** + * drm_gem_shmem_mmap - Memory-map a shmem GEM object + * @shmem: shmem GEM object + * @vma: VMA for the area to be mapped + * + * This function implements an augmented version of the GEM DRM file mmap + * operation for shmem objects. + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma) +{ + struct drm_gem_object *obj = &shmem->base; + int ret; + + if (drm_gem_is_imported(obj)) { + /* Reset both vm_ops and vm_private_data, so we don't end up with + * vm_ops pointing to our implementation if the dma-buf backend + * doesn't set those fields. + */ + vma->vm_private_data = NULL; + vma->vm_ops = NULL; + + ret = dma_buf_mmap(obj->dma_buf, vma, 0); + + /* Drop the reference drm_gem_mmap_obj() acquired.*/ + if (!ret) + drm_gem_object_put(obj); + + return ret; + } + + if (is_cow_mapping(vma->vm_flags)) + return -EINVAL; + + dma_resv_lock(shmem->base.resv, NULL); + ret = drm_gem_shmem_get_pages_locked(shmem); + dma_resv_unlock(shmem->base.resv); + + if (ret) + return ret; + + vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); + if (shmem->map_wc) + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); + + return 0; +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap); + +/** + * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs + * @shmem: shmem GEM object + * @p: DRM printer + * @indent: Tab indentation level + */ +void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem, + struct drm_printer *p, unsigned int indent) +{ + if (drm_gem_is_imported(&shmem->base)) + return; + + drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count)); + drm_printf_indent(p, indent, "pages_use_count=%u\n", refcount_read(&shmem->pages_use_count)); + drm_printf_indent(p, indent, "vmap_use_count=%u\n", refcount_read(&shmem->vmap_use_count)); + drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_print_info); + +/** + * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned + * pages for a shmem GEM object + * @shmem: shmem GEM object + * + * This function exports a scatter/gather table suitable for PRIME usage by + * calling the standard DMA mapping API. + * + * Drivers who need to acquire an scatter/gather table for objects need to call + * drm_gem_shmem_get_pages_sgt() instead. + * + * Returns: + * A pointer to the scatter/gather table of pinned pages or error pointer on failure. + */ +struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + + drm_WARN_ON(obj->dev, drm_gem_is_imported(obj)); + + return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table); + +static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + int ret; + struct sg_table *sgt; + + if (shmem->sgt) + return shmem->sgt; + + drm_WARN_ON(obj->dev, drm_gem_is_imported(obj)); + + ret = drm_gem_shmem_get_pages_locked(shmem); + if (ret) + return ERR_PTR(ret); + + sgt = drm_gem_shmem_get_sg_table(shmem); + if (IS_ERR(sgt)) { + ret = PTR_ERR(sgt); + goto err_put_pages; + } + /* Map the pages for use by the h/w. */ + ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0); + if (ret) + goto err_free_sgt; + + shmem->sgt = sgt; + + return sgt; + +err_free_sgt: + sg_free_table(sgt); + kfree(sgt); +err_put_pages: + drm_gem_shmem_put_pages_locked(shmem); + return ERR_PTR(ret); +} + +/** + * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a + * scatter/gather table for a shmem GEM object. + * @shmem: shmem GEM object + * + * This function returns a scatter/gather table suitable for driver usage. If + * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg + * table created. + * + * This is the main function for drivers to get at backing storage, and it hides + * and difference between dma-buf imported and natively allocated objects. + * drm_gem_shmem_get_sg_table() should not be directly called by drivers. + * + * Returns: + * A pointer to the scatter/gather table of pinned pages or errno on failure. + */ +struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem) +{ + int ret; + struct sg_table *sgt; + + ret = dma_resv_lock_interruptible(shmem->base.resv, NULL); + if (ret) + return ERR_PTR(ret); + sgt = drm_gem_shmem_get_pages_sgt_locked(shmem); + dma_resv_unlock(shmem->base.resv); + + return sgt; +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt); + +/** + * drm_gem_shmem_prime_import_sg_table - Produce a shmem 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. Drivers that use the shmem 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_shmem_prime_import_sg_table(struct drm_device *dev, + struct dma_buf_attachment *attach, + struct sg_table *sgt) +{ + size_t size = PAGE_ALIGN(attach->dmabuf->size); + struct drm_gem_shmem_object *shmem; + + shmem = __drm_gem_shmem_create(dev, size, true, NULL); + if (IS_ERR(shmem)) + return ERR_CAST(shmem); + + shmem->sgt = sgt; + + drm_dbg_prime(dev, "size = %zu\n", size); + + return &shmem->base; +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table); + +/** + * drm_gem_shmem_prime_import_no_map - Import dmabuf without mapping its sg_table + * @dev: Device to import into + * @dma_buf: dma-buf object to import + * + * Drivers that use the shmem helpers but also wants to import dmabuf without + * mapping its sg_table can use this as their &drm_driver.gem_prime_import + * implementation. + */ +struct drm_gem_object *drm_gem_shmem_prime_import_no_map(struct drm_device *dev, + struct dma_buf *dma_buf) +{ + struct dma_buf_attachment *attach; + struct drm_gem_shmem_object *shmem; + struct drm_gem_object *obj; + size_t size; + int ret; + + if (drm_gem_is_prime_exported_dma_buf(dev, dma_buf)) { + /* + * Importing dmabuf exported from our own gem increases + * refcount on gem itself instead of f_count of dmabuf. + */ + obj = dma_buf->priv; + drm_gem_object_get(obj); + return obj; + } + + attach = dma_buf_attach(dma_buf, dev->dev); + if (IS_ERR(attach)) + return ERR_CAST(attach); + + get_dma_buf(dma_buf); + + size = PAGE_ALIGN(attach->dmabuf->size); + + shmem = __drm_gem_shmem_create(dev, size, true, NULL); + if (IS_ERR(shmem)) { + ret = PTR_ERR(shmem); + goto fail_detach; + } + + drm_dbg_prime(dev, "size = %zu\n", size); + + shmem->base.import_attach = attach; + shmem->base.resv = dma_buf->resv; + + return &shmem->base; + +fail_detach: + dma_buf_detach(dma_buf, attach); + dma_buf_put(dma_buf); + + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_no_map); + +MODULE_DESCRIPTION("DRM SHMEM memory-management helpers"); +MODULE_IMPORT_NS("DMA_BUF"); +MODULE_LICENSE("GPL v2"); |