root/sys/dev/drm/include/drm/drm_gem_cma_helper.h
#ifndef __DRM_GEM_CMA_HELPER_H__
#define __DRM_GEM_CMA_HELPER_H__

#include <drm/drmP.h>
#include <drm/drm_gem.h>

/**
 * struct drm_gem_cma_object - GEM object backed by CMA memory allocations
 * @base: base GEM object
 * @paddr: physical address of the backing memory
 * @sgt: scatter/gather table for imported PRIME buffers. The table can have
 *       more than one entry but they are guaranteed to have contiguous
 *       DMA addresses.
 * @vaddr: kernel virtual address of the backing memory
 */
struct drm_gem_cma_object {
        struct drm_gem_object base;
        dma_addr_t paddr;
        struct sg_table *sgt;

        /* For objects with DMA memory allocated by GEM CMA */
        void *vaddr;
};

#define to_drm_gem_cma_obj(gem_obj) \
        container_of(gem_obj, struct drm_gem_cma_object, base)

#ifndef CONFIG_MMU
#define DRM_GEM_CMA_UNMAPPED_AREA_FOPS \
        .get_unmapped_area      = drm_gem_cma_get_unmapped_area,
#else
#define DRM_GEM_CMA_UNMAPPED_AREA_FOPS
#endif

/**
 * DEFINE_DRM_GEM_CMA_FOPS() - macro to generate file operations for CMA drivers
 * @name: name for the generated structure
 *
 * This macro autogenerates a suitable &struct file_operations for CMA based
 * drivers, which can be assigned to &drm_driver.fops. Note that this structure
 * cannot be shared between drivers, because it contains a reference to the
 * current module using THIS_MODULE.
 *
 * Note that the declaration is already marked as static - if you need a
 * non-static version of this you're probably doing it wrong and will break the
 * THIS_MODULE reference by accident.
 */
#define DEFINE_DRM_GEM_CMA_FOPS(name) \
        static const struct file_operations name = {\
                .owner          = THIS_MODULE,\
                .open           = drm_open,\
                .release        = drm_release,\
                .unlocked_ioctl = drm_ioctl,\
                .compat_ioctl   = drm_compat_ioctl,\
                .poll           = drm_poll,\
                .read           = drm_read,\
                .llseek         = noop_llseek,\
                .mmap           = drm_gem_cma_mmap,\
                DRM_GEM_CMA_UNMAPPED_AREA_FOPS \
        }

/* free GEM object */
void drm_gem_cma_free_object(struct drm_gem_object *gem_obj);

/* create memory region for DRM framebuffer */
int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
                                     struct drm_device *drm,
                                     struct drm_mode_create_dumb *args);

/* create memory region for DRM framebuffer */
int drm_gem_cma_dumb_create(struct drm_file *file_priv,
                            struct drm_device *drm,
                            struct drm_mode_create_dumb *args);

/* set vm_flags and we can change the VM attribute to other one at here */
int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);

/* allocate physical memory */
struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
                                              size_t size);

extern const struct vm_operations_struct drm_gem_cma_vm_ops;

#ifndef CONFIG_MMU
unsigned long drm_gem_cma_get_unmapped_area(struct file *filp,
                                            unsigned long addr,
                                            unsigned long len,
                                            unsigned long pgoff,
                                            unsigned long flags);
#endif

void drm_gem_cma_print_info(struct drm_printer *p, unsigned int indent,
                            const struct drm_gem_object *obj);

struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj);
struct drm_gem_object *
drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
                                  struct dma_buf_attachment *attach,
                                  struct sg_table *sgt);
int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
                           struct vm_area_struct *vma);
void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj);
void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr);

#endif /* __DRM_GEM_CMA_HELPER_H__ */