linux/drivers/gpu/drm/udl/udl_gem.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Red Hat
 */

#include <linux/dma-buf.h>
#include <linux/vmalloc.h>

#include <drm/drm_drv.h>
#include <drm/drm_gem_shmem_helper.h>
#include <drm/drm_mode.h>
#include <drm/drm_prime.h>

#include "udl_drv.h"

/*
 * GEM object funcs
 */

static void udl_gem_object_free_object(struct drm_gem_object *obj)
{
	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);

	/* Fbdev emulation vmaps the buffer. Unmap it here for consistency
	 * with the original udl GEM code.
	 *
	 * TODO: Switch to generic fbdev emulation and release the
	 *       GEM object with drm_gem_shmem_free_object().
	 */
	if (shmem->vaddr)
		drm_gem_shmem_vunmap(obj, shmem->vaddr);

	drm_gem_shmem_free_object(obj);
}

static int udl_gem_object_mmap(struct drm_gem_object *obj,
			       struct vm_area_struct *vma)
{
	int ret;

	ret = drm_gem_shmem_mmap(obj, vma);
	if (ret)
		return ret;

	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
	if (obj->import_attach)
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);

	return 0;
}

static void *udl_gem_object_vmap(struct drm_gem_object *obj)
{
	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
	int ret;

	ret = mutex_lock_interruptible(&shmem->vmap_lock);
	if (ret)
		return ERR_PTR(ret);

	if (shmem->vmap_use_count++ > 0)
		goto out;

	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;
	}

out:
	mutex_unlock(&shmem->vmap_lock);
	return shmem->vaddr;

err_put_pages:
	drm_gem_shmem_put_pages(shmem);
err_zero_use:
	shmem->vmap_use_count = 0;
	mutex_unlock(&shmem->vmap_lock);
	return ERR_PTR(ret);
}

static const struct drm_gem_object_funcs udl_gem_object_funcs = {
	.free = udl_gem_object_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 = udl_gem_object_vmap,
	.vunmap = drm_gem_shmem_vunmap,
	.mmap = udl_gem_object_mmap,
};

/*
 * Helpers for struct drm_driver
 */

struct drm_gem_object *udl_driver_gem_create_object(struct drm_device *dev,
						    size_t size)
{
	struct drm_gem_shmem_object *shmem;
	struct drm_gem_object *obj;

	shmem = kzalloc(sizeof(*shmem), GFP_KERNEL);
	if (!shmem)
		return NULL;

	obj = &shmem->base;
	obj->funcs = &udl_gem_object_funcs;

	return obj;
}

struct udl_gem_object *udl_gem_alloc_object(struct drm_device *dev,
					    size_t size)
{
	struct drm_gem_object *obj;

	obj = dev->driver->gem_create_object(dev, size);
	if (obj == NULL)
		return NULL;

	if (drm_gem_object_init(dev, obj, size) != 0) {
		kfree(obj);
		return NULL;
	}

	return to_udl_bo(obj);
}

static int
udl_gem_create(struct drm_file *file,
	       struct drm_device *dev,
	       uint64_t size,
	       uint32_t *handle_p)
{
	struct udl_gem_object *obj;
	int ret;
	u32 handle;

	size = roundup(size, PAGE_SIZE);

	obj = udl_gem_alloc_object(dev, size);
	if (obj == NULL)
		return -ENOMEM;

	ret = drm_gem_handle_create(file, &obj->base, &handle);
	if (ret) {
		drm_gem_object_release(&obj->base);
		kfree(obj);
		return ret;
	}

	drm_gem_object_put_unlocked(&obj->base);
	*handle_p = handle;
	return 0;
}

int udl_dumb_create(struct drm_file *file,
		    struct drm_device *dev,
		    struct drm_mode_create_dumb *args)
{
	args->pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
	args->size = args->pitch * args->height;
	return udl_gem_create(file, dev,
			      args->size, &args->handle);
}

int udl_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct drm_gem_object *obj;
	int ret;

	ret = drm_gem_mmap(filp, vma);
	if (ret)
		return ret;

	obj = vma->vm_private_data;

	vma->vm_flags &= ~VM_PFNMAP;
	vma->vm_flags |= VM_MIXEDMAP;

	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
	if (obj->import_attach)
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	return ret;
}

vm_fault_t udl_gem_fault(struct vm_fault *vmf)
{
	struct vm_area_struct *vma = vmf->vma;
	struct udl_gem_object *obj = to_udl_bo(vma->vm_private_data);
	struct page *page;
	unsigned int page_offset;

	page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;

	if (!obj->pages)
		return VM_FAULT_SIGBUS;

	page = obj->pages[page_offset];
	return vmf_insert_page(vma, vmf->address, page);
}

int udl_gem_get_pages(struct udl_gem_object *obj)
{
	struct page **pages;

	if (obj->pages)
		return 0;

	pages = drm_gem_get_pages(&obj->base);
	if (IS_ERR(pages))
		return PTR_ERR(pages);

	obj->pages = pages;

	return 0;
}

void udl_gem_put_pages(struct udl_gem_object *obj)
{
	if (obj->base.import_attach) {
		kvfree(obj->pages);
		obj->pages = NULL;
		return;
	}

	drm_gem_put_pages(&obj->base, obj->pages, false, false);
	obj->pages = NULL;
}

int udl_gem_vmap(struct udl_gem_object *obj)
{
	int page_count = obj->base.size / PAGE_SIZE;
	int ret;

	if (obj->base.import_attach) {
		obj->vmapping = dma_buf_vmap(obj->base.import_attach->dmabuf);
		if (!obj->vmapping)
			return -ENOMEM;
		return 0;
	}

	ret = udl_gem_get_pages(obj);
	if (ret)
		return ret;

	obj->vmapping = vmap(obj->pages, page_count, 0, PAGE_KERNEL);
	if (!obj->vmapping)
		return -ENOMEM;
	return 0;
}

void udl_gem_vunmap(struct udl_gem_object *obj)
{
	if (obj->base.import_attach) {
		dma_buf_vunmap(obj->base.import_attach->dmabuf, obj->vmapping);
		return;
	}

	vunmap(obj->vmapping);

	udl_gem_put_pages(obj);
}

void udl_gem_free_object(struct drm_gem_object *gem_obj)
{
	struct udl_gem_object *obj = to_udl_bo(gem_obj);

	if (obj->vmapping)
		udl_gem_vunmap(obj);

	if (gem_obj->import_attach) {
		drm_prime_gem_destroy(gem_obj, obj->sg);
		put_device(gem_obj->dev->dev);
	}

	if (obj->pages)
		udl_gem_put_pages(obj);

	drm_gem_free_mmap_offset(gem_obj);
}

/* the dumb interface doesn't work with the GEM straight MMAP
   interface, it expects to do MMAP on the drm fd, like normal */
int udl_gem_mmap(struct drm_file *file, struct drm_device *dev,
		 uint32_t handle, uint64_t *offset)
{
	struct udl_gem_object *gobj;
	struct drm_gem_object *obj;
	struct udl_device *udl = to_udl(dev);
	int ret = 0;

	mutex_lock(&udl->gem_lock);
	obj = drm_gem_object_lookup(file, handle);
	if (obj == NULL) {
		ret = -ENOENT;
		goto unlock;
	}
	gobj = to_udl_bo(obj);

	ret = udl_gem_get_pages(gobj);
	if (ret)
		goto out;
	ret = drm_gem_create_mmap_offset(obj);
	if (ret)
		goto out;

	*offset = drm_vma_node_offset_addr(&gobj->base.vma_node);

out:
	drm_gem_object_put_unlocked(&gobj->base);
unlock:
	mutex_unlock(&udl->gem_lock);
	return ret;
}