/*
 * Copyright (c) 2016 Intel Corporation
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#ifndef __DRM_FRAMEBUFFER_H__
#define __DRM_FRAMEBUFFER_H__

#include <linux/list.h>
#include <linux/ctype.h>
#include <drm/drm_mode_object.h>

struct drm_framebuffer;
struct drm_file;
struct drm_device;

/**
 * struct drm_framebuffer_funcs - framebuffer hooks
 */
struct drm_framebuffer_funcs {
        /**
         * @destroy:
         *
         * Clean up framebuffer resources, specifically also unreference the
         * backing storage. The core guarantees to call this function for every
         * framebuffer successfully created by ->fb_create() in
         * &drm_mode_config_funcs. Drivers must also call
         * drm_framebuffer_cleanup() to release DRM core resources for this
         * framebuffer.
         */
        void (*destroy)(struct drm_framebuffer *framebuffer);

        /**
         * @create_handle:
         *
         * Create a buffer handle in the driver-specific buffer manager (either
         * GEM or TTM) valid for the passed-in struct &drm_file. This is used by
         * the core to implement the GETFB IOCTL, which returns (for
         * sufficiently priviledged user) also a native buffer handle. This can
         * be used for seamless transitions between modesetting clients by
         * copying the current screen contents to a private buffer and blending
         * between that and the new contents.
         *
         * GEM based drivers should call drm_gem_handle_create() to create the
         * handle.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*create_handle)(struct drm_framebuffer *fb,
                             struct drm_file *file_priv,
                             unsigned int *handle);
        /**
         * @dirty:
         *
         * Optional callback for the dirty fb IOCTL.
         *
         * Userspace can notify the driver via this callback that an area of the
         * framebuffer has changed and should be flushed to the display
         * hardware. This can also be used internally, e.g. by the fbdev
         * emulation, though that's not the case currently.
         *
         * See documentation in drm_mode.h for the struct drm_mode_fb_dirty_cmd
         * for more information as all the semantics and arguments have a one to
         * one mapping on this function.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*dirty)(struct drm_framebuffer *framebuffer,
                     struct drm_file *file_priv, unsigned flags,
                     unsigned color, struct drm_clip_rect *clips,
                     unsigned num_clips);
};

/**
 * struct drm_framebuffer - frame buffer object
 *
 * Note that the fb is refcounted for the benefit of driver internals,
 * for example some hw, disabling a CRTC/plane is asynchronous, and
 * scanout does not actually complete until the next vblank.  So some
 * cleanup (like releasing the reference(s) on the backing GEM bo(s))
 * should be deferred.  In cases like this, the driver would like to
 * hold a ref to the fb even though it has already been removed from
 * userspace perspective. See drm_framebuffer_reference() and
 * drm_framebuffer_unreference().
 *
 * The refcount is stored inside the mode object @base.
 */
struct drm_framebuffer {
        /**
         * @dev: DRM device this framebuffer belongs to
         */
        struct drm_device *dev;
        /**
         * @head: Place on the dev->mode_config.fb_list, access protected by
         * dev->mode_config.fb_lock.
         */
        struct list_head head;

        /**
         * @base: base modeset object structure, contains the reference count.
         */
        struct drm_mode_object base;
        /**
         * @funcs: framebuffer vfunc table
         */
        const struct drm_framebuffer_funcs *funcs;
        /**
         * @pitches: Line stride per buffer. For userspace created object this
         * is copied from drm_mode_fb_cmd2.
         */
        unsigned int pitches[4];
        /**
         * @offsets: Offset from buffer start to the actual pixel data in bytes,
         * per buffer. For userspace created object this is copied from
         * drm_mode_fb_cmd2.
         *
         * Note that this is a linear offset and does not take into account
         * tiling or buffer laytou per @modifier. It meant to be used when the
         * actual pixel data for this framebuffer plane starts at an offset,
         * e.g.  when multiple planes are allocated within the same backing
         * storage buffer object. For tiled layouts this generally means it
         * @offsets must at least be tile-size aligned, but hardware often has
         * stricter requirements.
         *
         * This should not be used to specifiy x/y pixel offsets into the buffer
         * data (even for linear buffers). Specifying an x/y pixel offset is
         * instead done through the source rectangle in struct &drm_plane_state.
         */
        unsigned int offsets[4];
        /**
         * @modifier: Data layout modifier, per buffer. This is used to describe
         * tiling, or also special layouts (like compression) of auxiliary
         * buffers. For userspace created object this is copied from
         * drm_mode_fb_cmd2.
         */
        uint64_t modifier[4];
        /**
         * @width: Logical width of the visible area of the framebuffer, in
         * pixels.
         */
        unsigned int width;
        /**
         * @height: Logical height of the visible area of the framebuffer, in
         * pixels.
         */
        unsigned int height;
        /**
         * @depth: Depth in bits per pixel for RGB formats. 0 for everything
         * else. Legacy information derived from @pixel_format, it's suggested to use
         * the DRM FOURCC codes and helper functions directly instead.
         */
        unsigned int depth;
        /**
         * @bits_per_pixel: Storage used bits per pixel for RGB formats. 0 for
         * everything else. Legacy information derived from @pixel_format, it's
         * suggested to use the DRM FOURCC codes and helper functions directly
         * instead.
         */
        int bits_per_pixel;
        /**
         * @flags: Framebuffer flags like DRM_MODE_FB_INTERLACED or
         * DRM_MODE_FB_MODIFIERS.
         */
        int flags;
        /**
         * @pixel_format: DRM FOURCC code describing the pixel format.
         */
        uint32_t pixel_format; /* fourcc format */
        /**
         * @hot_x: X coordinate of the cursor hotspot. Used by the legacy cursor
         * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
         * universal plane.
         */
        int hot_x;
        /**
         * @hot_y: Y coordinate of the cursor hotspot. Used by the legacy cursor
         * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
         * universal plane.
         */
        int hot_y;
        /**
         * @filp_head: Placed on struct &drm_file fbs list_head, protected by
         * fbs_lock in the same structure.
         */
        struct list_head filp_head;
};

#define obj_to_fb(x) container_of(x, struct drm_framebuffer, base)

int drm_framebuffer_init(struct drm_device *dev,
                         struct drm_framebuffer *fb,
                         const struct drm_framebuffer_funcs *funcs);
struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
                                               uint32_t id);
void drm_framebuffer_remove(struct drm_framebuffer *fb);
void drm_framebuffer_cleanup(struct drm_framebuffer *fb);
void drm_framebuffer_unregister_private(struct drm_framebuffer *fb);

/**
 * drm_framebuffer_reference - incr the fb refcnt
 * @fb: framebuffer
 *
 * This functions increments the fb's refcount.
 */
static inline void drm_framebuffer_reference(struct drm_framebuffer *fb)
{
        drm_mode_object_reference(&fb->base);
}

/**
 * drm_framebuffer_unreference - unref a framebuffer
 * @fb: framebuffer to unref
 *
 * This functions decrements the fb's refcount and frees it if it drops to zero.
 */
static inline void drm_framebuffer_unreference(struct drm_framebuffer *fb)
{
        drm_mode_object_unreference(&fb->base);
}

/**
 * drm_framebuffer_read_refcount - read the framebuffer reference count.
 * @fb: framebuffer
 *
 * This functions returns the framebuffer's reference count.
 */
static inline uint32_t drm_framebuffer_read_refcount(struct drm_framebuffer *fb)
{
        return atomic_read(&fb->base.refcount.refcount);
}

/**
 * drm_for_each_fb - iterate over all framebuffers
 * @fb: the loop cursor
 * @dev: the DRM device
 *
 * Iterate over all framebuffers of @dev. User must hold the fb_lock from
 * &drm_mode_config.
 */
#define drm_for_each_fb(fb, dev) \
        for (WARN_ON(!mutex_is_locked(&(dev)->mode_config.fb_lock)),            \
             fb = list_first_entry(&(dev)->mode_config.fb_list, \
                                          struct drm_framebuffer, head);        \
             &fb->head != (&(dev)->mode_config.fb_list);                        \
             fb = list_next_entry(fb, head))
#endif