drivers/gpu/drm/xe/xe_mmio_gem.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/xe/xe_mmio_gem.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/xe/xe_mmio_gem.c
Extension
.c
Size
6050 bytes
Lines
227
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct xe_mmio_gem {
	struct drm_gem_object base;
	phys_addr_t phys_addr;
};

static const struct vm_operations_struct vm_ops = {
	.open = drm_gem_vm_open,
	.close = drm_gem_vm_close,
	.fault = xe_mmio_gem_vm_fault,
};

static const struct drm_gem_object_funcs xe_mmio_gem_funcs = {
	.free = xe_mmio_gem_free,
	.mmap = xe_mmio_gem_mmap,
	.vm_ops = &vm_ops,
};

static inline struct xe_mmio_gem *to_xe_mmio_gem(struct drm_gem_object *obj)
{
	return container_of(obj, struct xe_mmio_gem, base);
}

/**
 * xe_mmio_gem_create - Expose an MMIO region to userspace
 * @xe: The xe device
 * @file: DRM file descriptor
 * @phys_addr: Start of the exposed MMIO region
 * @size: The size of the exposed MMIO region
 *
 * This function creates a GEM object that exposes an MMIO region with an mmap-able
 * fake offset.
 *
 * See: "Exposing MMIO regions to userspace"
 */
struct xe_mmio_gem *xe_mmio_gem_create(struct xe_device *xe, struct drm_file *file,
				       phys_addr_t phys_addr, size_t size)
{
	struct xe_mmio_gem *obj;
	struct drm_gem_object *base;
	int err;

	if ((phys_addr % PAGE_SIZE != 0) || (size % PAGE_SIZE != 0))
		return ERR_PTR(-EINVAL);

	obj = kzalloc_obj(*obj);
	if (!obj)
		return ERR_PTR(-ENOMEM);

	base = &obj->base;
	base->funcs = &xe_mmio_gem_funcs;
	obj->phys_addr = phys_addr;

	drm_gem_private_object_init(&xe->drm, base, size);

	err = drm_gem_create_mmap_offset(base);
	if (err)
		goto free_gem;

	err = drm_vma_node_allow(&base->vma_node, file);
	if (err)
		goto free_gem;

	return obj;

free_gem:
	xe_mmio_gem_free(base);
	return ERR_PTR(err);
}

/**
 * xe_mmio_gem_mmap_offset - Return the mmap-able fake offset
 * @gem: the GEM object created with xe_mmio_gem_create()
 *
 * This function returns the mmap-able fake offset allocated during
 * xe_mmio_gem_create().
 *
 * See: "Exposing MMIO regions to userspace"
 */
u64 xe_mmio_gem_mmap_offset(struct xe_mmio_gem *gem)
{
	return drm_vma_node_offset_addr(&gem->base.vma_node);
}

static void xe_mmio_gem_free(struct drm_gem_object *base)
{
	struct xe_mmio_gem *obj = to_xe_mmio_gem(base);

	drm_gem_object_release(base);
	kfree(obj);
}

Annotation

Implementation Notes