diff options
Diffstat (limited to 'drivers/gpu/drm/drm_gem_shmem_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_gem_shmem_helper.c | 625 |
1 files changed, 625 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..1ee208c2c85e --- /dev/null +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -0,0 +1,625 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2018 Noralf Trønnes + */ + +#include <linux/dma-buf.h> +#include <linux/export.h> +#include <linux/mutex.h> +#include <linux/shmem_fs.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> + +#include <drm/drm_device.h> +#include <drm/drm_drv.h> +#include <drm/drm_gem_shmem_helper.h> +#include <drm/drm_prime.h> +#include <drm/drm_print.h> + +/** + * DOC: overview + * + * This library provides helpers for GEM objects backed by shmem buffers + * allocated using anonymous pageable memory. + */ + +static const struct drm_gem_object_funcs drm_gem_shmem_funcs = { + .free = drm_gem_shmem_free_object, + .print_info = drm_gem_shmem_print_info, + .pin = drm_gem_shmem_pin, + .unpin = drm_gem_shmem_unpin, + .get_sg_table = drm_gem_shmem_get_sg_table, + .vmap = drm_gem_shmem_vmap, + .vunmap = drm_gem_shmem_vunmap, + .vm_ops = &drm_gem_shmem_vm_ops, +}; + +/** + * 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) +{ + struct drm_gem_shmem_object *shmem; + struct drm_gem_object *obj; + int ret; + + size = PAGE_ALIGN(size); + + if (dev->driver->gem_create_object) + obj = dev->driver->gem_create_object(dev, size); + else + obj = kzalloc(sizeof(*shmem), GFP_KERNEL); + if (!obj) + return ERR_PTR(-ENOMEM); + + if (!obj->funcs) + obj->funcs = &drm_gem_shmem_funcs; + + ret = drm_gem_object_init(dev, obj, size); + if (ret) + goto err_free; + + ret = drm_gem_create_mmap_offset(obj); + if (ret) + goto err_release; + + shmem = to_drm_gem_shmem_obj(obj); + mutex_init(&shmem->pages_lock); + mutex_init(&shmem->vmap_lock); + + /* + * 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 shmem; + +err_release: + drm_gem_object_release(obj); +err_free: + kfree(obj); + + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_create); + +/** + * drm_gem_shmem_free_object - Free resources associated with a shmem GEM object + * @obj: 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_object(struct drm_gem_object *obj) +{ + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + + WARN_ON(shmem->vmap_use_count); + + if (obj->import_attach) { + shmem->pages_use_count--; + drm_prime_gem_destroy(obj, shmem->sgt); + kvfree(shmem->pages); + } else { + if (shmem->sgt) { + dma_unmap_sg(obj->dev->dev, shmem->sgt->sgl, + shmem->sgt->nents, DMA_BIDIRECTIONAL); + + drm_gem_shmem_put_pages(shmem); + sg_free_table(shmem->sgt); + kfree(shmem->sgt); + } + } + + WARN_ON(shmem->pages_use_count); + + drm_gem_object_release(obj); + mutex_destroy(&shmem->pages_lock); + mutex_destroy(&shmem->vmap_lock); + kfree(shmem); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_free_object); + +static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + struct page **pages; + + if (shmem->pages_use_count++ > 0) + return 0; + + pages = drm_gem_get_pages(obj); + if (IS_ERR(pages)) { + DRM_DEBUG_KMS("Failed to get pages (%ld)\n", PTR_ERR(pages)); + shmem->pages_use_count = 0; + return PTR_ERR(pages); + } + + shmem->pages = pages; + + return 0; +} + +/* + * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object + * @shmem: shmem GEM object + * + * This function makes sure that backing pages exists for the shmem GEM object + * and increases the use count. + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem) +{ + int ret; + + ret = mutex_lock_interruptible(&shmem->pages_lock); + if (ret) + return ret; + ret = drm_gem_shmem_get_pages_locked(shmem); + mutex_unlock(&shmem->pages_lock); + + return ret; +} +EXPORT_SYMBOL(drm_gem_shmem_get_pages); + +static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + + if (WARN_ON_ONCE(!shmem->pages_use_count)) + return; + + if (--shmem->pages_use_count > 0) + return; + + drm_gem_put_pages(obj, shmem->pages, + shmem->pages_mark_dirty_on_put, + shmem->pages_mark_accessed_on_put); + shmem->pages = NULL; +} + +/* + * drm_gem_shmem_put_pages - 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(struct drm_gem_shmem_object *shmem) +{ + mutex_lock(&shmem->pages_lock); + drm_gem_shmem_put_pages_locked(shmem); + mutex_unlock(&shmem->pages_lock); +} +EXPORT_SYMBOL(drm_gem_shmem_put_pages); + +/** + * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object + * @obj: 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_object *obj) +{ + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + + return drm_gem_shmem_get_pages(shmem); +} +EXPORT_SYMBOL(drm_gem_shmem_pin); + +/** + * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object + * @obj: GEM object + * + * This function removes the requirement that the backing pages are pinned in + * memory. + */ +void drm_gem_shmem_unpin(struct drm_gem_object *obj) +{ + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + + drm_gem_shmem_put_pages(shmem); +} +EXPORT_SYMBOL(drm_gem_shmem_unpin); + +static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + int ret; + + if (shmem->vmap_use_count++ > 0) + return shmem->vaddr; + + ret = drm_gem_shmem_get_pages(shmem); + if (ret) + goto err_zero_use; + + if (obj->import_attach) + shmem->vaddr = dma_buf_vmap(obj->import_attach->dmabuf); + else + shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT, VM_MAP, PAGE_KERNEL); + + if (!shmem->vaddr) { + DRM_DEBUG_KMS("Failed to vmap pages\n"); + ret = -ENOMEM; + goto err_put_pages; + } + + return shmem->vaddr; + +err_put_pages: + drm_gem_shmem_put_pages(shmem); +err_zero_use: + shmem->vmap_use_count = 0; + + return ERR_PTR(ret); +} + +/* + * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object + * @shmem: shmem GEM object + * + * This function makes sure that a virtual address exists for the buffer backing + * the shmem GEM object. + * + * Returns: + * 0 on success or a negative error code on failure. + */ +void *drm_gem_shmem_vmap(struct drm_gem_object *obj) +{ + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + void *vaddr; + int ret; + + ret = mutex_lock_interruptible(&shmem->vmap_lock); + if (ret) + return ERR_PTR(ret); + vaddr = drm_gem_shmem_vmap_locked(shmem); + mutex_unlock(&shmem->vmap_lock); + + return vaddr; +} +EXPORT_SYMBOL(drm_gem_shmem_vmap); + +static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem) +{ + struct drm_gem_object *obj = &shmem->base; + + if (WARN_ON_ONCE(!shmem->vmap_use_count)) + return; + + if (--shmem->vmap_use_count > 0) + return; + + if (obj->import_attach) + dma_buf_vunmap(obj->import_attach->dmabuf, shmem->vaddr); + else + vunmap(shmem->vaddr); + + shmem->vaddr = NULL; + drm_gem_shmem_put_pages(shmem); +} + +/* + * drm_gem_shmem_vunmap - Unmap a virtual mapping fo a shmem GEM object + * @shmem: shmem GEM object + * + * This function removes the virtual address when use count drops to zero. + */ +void drm_gem_shmem_vunmap(struct drm_gem_object *obj, void *vaddr) +{ + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + + mutex_lock(&shmem->vmap_lock); + drm_gem_shmem_vunmap_locked(shmem); + mutex_unlock(&shmem->vmap_lock); +} +EXPORT_SYMBOL(drm_gem_shmem_vunmap); + +struct drm_gem_shmem_object * +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 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_unlocked(&shmem->base); + if (ret) + return ERR_PTR(ret); + + return shmem; +} +EXPORT_SYMBOL(drm_gem_shmem_create_with_handle); + +/** + * 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) +{ + u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8); + struct drm_gem_shmem_object *shmem; + + if (!args->pitch || !args->size) { + args->pitch = min_pitch; + args->size = args->pitch * args->height; + } else { + /* ensure sane minimum values */ + if (args->pitch < min_pitch) + args->pitch = min_pitch; + if (args->size < args->pitch * args->height) + args->size = args->pitch * args->height; + } + + shmem = drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle); + + return PTR_ERR_OR_ZERO(shmem); +} +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; + struct page *page; + + if (vmf->pgoff >= num_pages || WARN_ON_ONCE(!shmem->pages)) + return VM_FAULT_SIGBUS; + + page = shmem->pages[vmf->pgoff]; + + return vmf_insert_page(vma, vmf->address, page); +} + +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); + int ret; + + ret = drm_gem_shmem_get_pages(shmem); + WARN_ON_ONCE(ret != 0); + + 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); + + drm_gem_shmem_put_pages(shmem); + 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 + * @filp: File 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. Drivers which employ the shmem helpers should + * use this function as their &file_operations.mmap handler in the DRM device file's + * file_operations structure. + * + * Instead of directly referencing this function, drivers should use the + * DEFINE_DRM_GEM_SHMEM_FOPS() macro. + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_shmem_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct drm_gem_shmem_object *shmem; + int ret; + + ret = drm_gem_mmap(filp, vma); + if (ret) + return ret; + + shmem = to_drm_gem_shmem_obj(vma->vm_private_data); + + ret = drm_gem_shmem_get_pages(shmem); + if (ret) { + drm_gem_vm_close(vma); + return ret; + } + + /* VM_PFNMAP was set by drm_gem_mmap() */ + vma->vm_flags &= ~VM_PFNMAP; + vma->vm_flags |= VM_MIXEDMAP; + + /* Remove the fake offset */ + vma->vm_pgoff -= drm_vma_node_start(&shmem->base.vma_node); + + return 0; +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap); + +/** + * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs + * @p: DRM printer + * @indent: Tab indentation level + * @obj: GEM object + */ +void drm_gem_shmem_print_info(struct drm_printer *p, unsigned int indent, + const struct drm_gem_object *obj) +{ + const struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + + drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count); + drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count); + drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr); +} +EXPORT_SYMBOL(drm_gem_shmem_print_info); + +/** + * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned + * pages for a shmem GEM object + * @obj: GEM object + * + * This function exports a scatter/gather table suitable for PRIME usage 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_shmem_get_sg_table(struct drm_gem_object *obj) +{ + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + + return drm_prime_pages_to_sg(shmem->pages, obj->size >> PAGE_SHIFT); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table); + +/** + * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a + * scatter/gather table for a shmem GEM object. + * @obj: 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. + * + * 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_object *obj) +{ + int ret; + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + struct sg_table *sgt; + + if (shmem->sgt) + return shmem->sgt; + + WARN_ON(obj->import_attach); + + ret = drm_gem_shmem_get_pages(shmem); + if (ret) + return ERR_PTR(ret); + + sgt = drm_gem_shmem_get_sg_table(&shmem->base); + if (IS_ERR(sgt)) { + ret = PTR_ERR(sgt); + goto err_put_pages; + } + /* Map the pages for use by the h/w. */ + dma_map_sg(obj->dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL); + + shmem->sgt = sgt; + + return sgt; + +err_put_pages: + drm_gem_shmem_put_pages(shmem); + return ERR_PTR(ret); +} +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); + size_t npages = size >> PAGE_SHIFT; + struct drm_gem_shmem_object *shmem; + int ret; + + shmem = drm_gem_shmem_create(dev, size); + if (IS_ERR(shmem)) + return ERR_CAST(shmem); + + shmem->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL); + if (!shmem->pages) { + ret = -ENOMEM; + goto err_free_gem; + } + + ret = drm_prime_sg_to_page_addr_arrays(sgt, shmem->pages, NULL, npages); + if (ret < 0) + goto err_free_array; + + shmem->sgt = sgt; + shmem->pages_use_count = 1; /* Permanently pinned from our point of view */ + + DRM_DEBUG_PRIME("size = %zu\n", size); + + return &shmem->base; + +err_free_array: + kvfree(shmem->pages); +err_free_gem: + drm_gem_object_put_unlocked(&shmem->base); + + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table); |