xref: /Linux-v6.6/include/drm/drm_fb_helper.h

/*
 * Copyright (c) 2006-2009 Red Hat Inc.
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
 *
 * DRM framebuffer helper functions
 *
 * 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.
 *
 * Authors:
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */
#ifndef DRM_FB_HELPER_H
#define DRM_FB_HELPER_H

struct drm_clip_rect;
struct drm_fb_helper;

#include <linux/fb.h>

#include <drm/drm_client.h>

/**
 * struct drm_fb_helper_surface_size - describes fbdev size and scanout surface size
 * @fb_width: fbdev width
 * @fb_height: fbdev height
 * @surface_width: scanout buffer width
 * @surface_height: scanout buffer height
 * @surface_bpp: scanout buffer bpp
 * @surface_depth: scanout buffer depth
 *
 * Note that the scanout surface width/height may be larger than the fbdev
 * width/height.  In case of multiple displays, the scanout surface is sized
 * according to the largest width/height (so it is large enough for all CRTCs
 * to scanout).  But the fbdev width/height is sized to the minimum width/
 * height of all the displays.  This ensures that fbcon fits on the smallest
 * of the attached displays. fb_width/fb_height is used by
 * drm_fb_helper_fill_info() to fill out the &fb_info.var structure.
 */
struct drm_fb_helper_surface_size {
	u32 fb_width;
	u32 fb_height;
	u32 surface_width;
	u32 surface_height;
	u32 surface_bpp;
	u32 surface_depth;
};

/**
 * struct drm_fb_helper_funcs - driver callbacks for the fbdev emulation library
 *
 * Driver callbacks used by the fbdev emulation helper library.
 */
struct drm_fb_helper_funcs {
	/**
	 * @fb_probe:
	 *
	 * Driver callback to allocate and initialize the fbdev info structure.
	 * Furthermore it also needs to allocate the DRM framebuffer used to
	 * back the fbdev.
	 *
	 * This callback is mandatory.
	 *
	 * RETURNS:
	 *
	 * The driver should return 0 on success and a negative error code on
	 * failure.
	 */
	int (*fb_probe)(struct drm_fb_helper *helper,
			struct drm_fb_helper_surface_size *sizes);

	/**
	 * @fb_dirty:
	 *
	 * Driver callback to update the framebuffer memory. If set, fbdev
	 * emulation will invoke this callback in regular intervals after
	 * the framebuffer has been written.
	 *
	 * This callback is optional.
	 *
	 * Returns:
	 * 0 on success, or an error code otherwise.
	 */
	int (*fb_dirty)(struct drm_fb_helper *helper, struct drm_clip_rect *clip);
};

/**
 * struct drm_fb_helper - main structure to emulate fbdev on top of KMS
 * @fb: Scanout framebuffer object
 * @dev: DRM device
 * @funcs: driver callbacks for fb helper
 * @info: emulated fbdev device info struct
 * @pseudo_palette: fake palette of 16 colors
 * @damage_clip: clip rectangle used with deferred_io to accumulate damage to
 *                the screen buffer
 * @damage_lock: spinlock protecting @damage_clip
 * @damage_work: worker used to flush the framebuffer
 * @resume_work: worker used during resume if the console lock is already taken
 *
 * This is the main structure used by the fbdev helpers. Drivers supporting
 * fbdev emulation should embedded this into their overall driver structure.
 * Drivers must also fill out a &struct drm_fb_helper_funcs with a few
 * operations.
 */
struct drm_fb_helper {
	/**
	 * @client:
	 *
	 * DRM client used by the generic fbdev emulation.
	 */
	struct drm_client_dev client;

	/**
	 * @buffer:
	 *
	 * Framebuffer used by the generic fbdev emulation.
	 */
	struct drm_client_buffer *buffer;

	struct drm_framebuffer *fb;
	struct drm_device *dev;
	const struct drm_fb_helper_funcs *funcs;
	struct fb_info *info;
	u32 pseudo_palette[17];
	struct drm_clip_rect damage_clip;
	spinlock_t damage_lock;
	struct work_struct damage_work;
	struct work_struct resume_work;

	/**
	 * @lock:
	 *
	 * Top-level FBDEV helper lock. This protects all internal data
	 * structures and lists, such as @connector_info and @crtc_info.
	 *
	 * FIXME: fbdev emulation locking is a mess and long term we want to
	 * protect all helper internal state with this lock as well as reduce
	 * core KMS locking as much as possible.
	 */
	struct mutex lock;

	/**
	 * @kernel_fb_list:
	 *
	 * Entry on the global kernel_fb_helper_list, used for kgdb entry/exit.
	 */
	struct list_head kernel_fb_list;

	/**
	 * @delayed_hotplug:
	 *
	 * A hotplug was received while fbdev wasn't in control of the DRM
	 * device, i.e. another KMS master was active. The output configuration
	 * needs to be reprobe when fbdev is in control again.
	 */
	bool delayed_hotplug;

	/**
	 * @deferred_setup:
	 *
	 * If no outputs are connected (disconnected or unknown) the FB helper
	 * code will defer setup until at least one of the outputs shows up.
	 * This field keeps track of the status so that setup can be retried
	 * at every hotplug event until it succeeds eventually.
	 *
	 * Protected by @lock.
	 */
	bool deferred_setup;

	/**
	 * @preferred_bpp:
	 *
	 * Temporary storage for the driver's preferred BPP setting passed to
	 * FB helper initialization. This needs to be tracked so that deferred
	 * FB helper setup can pass this on.
	 *
	 * See also: @deferred_setup
	 */
	int preferred_bpp;

#ifdef CONFIG_FB_DEFERRED_IO
	/**
	 * @fbdefio:
	 *
	 * Temporary storage for the driver's FB deferred I/O handler. If the
	 * driver uses the DRM fbdev emulation layer, this is set by the core
	 * to a generic deferred I/O handler if a driver is preferring to use
	 * a shadow buffer.
	 */
	struct fb_deferred_io fbdefio;
#endif
};

static inline struct drm_fb_helper *
drm_fb_helper_from_client(struct drm_client_dev *client)
{
	return container_of(client, struct drm_fb_helper, client);
}

/**
 * define DRM_FB_HELPER_DEFAULT_OPS - helper define for drm drivers
 *
 * Helper define to register default implementations of drm_fb_helper
 * functions. To be used in struct fb_ops of drm drivers.
 */
#define DRM_FB_HELPER_DEFAULT_OPS \
	.fb_check_var	= drm_fb_helper_check_var, \
	.fb_set_par	= drm_fb_helper_set_par, \
	.fb_setcmap	= drm_fb_helper_setcmap, \
	.fb_blank	= drm_fb_helper_blank, \
	.fb_pan_display	= drm_fb_helper_pan_display, \
	.fb_debug_enter = drm_fb_helper_debug_enter, \
	.fb_debug_leave = drm_fb_helper_debug_leave, \
	.fb_ioctl	= drm_fb_helper_ioctl

#ifdef CONFIG_DRM_FBDEV_EMULATION
void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
			   unsigned int preferred_bpp,
			   const struct drm_fb_helper_funcs *funcs);
void drm_fb_helper_unprepare(struct drm_fb_helper *fb_helper);
int drm_fb_helper_init(struct drm_device *dev, struct drm_fb_helper *helper);
void drm_fb_helper_fini(struct drm_fb_helper *helper);
int drm_fb_helper_blank(int blank, struct fb_info *info);
int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
			      struct fb_info *info);
int drm_fb_helper_set_par(struct fb_info *info);
int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
			    struct fb_info *info);

int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper);

struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper);
void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper);
void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper);
void drm_fb_helper_fill_info(struct fb_info *info,
			     struct drm_fb_helper *fb_helper,
			     struct drm_fb_helper_surface_size *sizes);

void drm_fb_helper_damage_range(struct fb_info *info, off_t off, size_t len);
void drm_fb_helper_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height);

void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagereflist);

void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, bool suspend);
void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
					bool suspend);

int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info);

int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
			unsigned long arg);

int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper);
int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper);
int drm_fb_helper_debug_enter(struct fb_info *info);
int drm_fb_helper_debug_leave(struct fb_info *info);

void drm_fb_helper_lastclose(struct drm_device *dev);
void drm_fb_helper_output_poll_changed(struct drm_device *dev);
#else
static inline void drm_fb_helper_prepare(struct drm_device *dev,
					 struct drm_fb_helper *helper,
					 unsigned int preferred_bpp,
					 const struct drm_fb_helper_funcs *funcs)
{
}

static inline void drm_fb_helper_unprepare(struct drm_fb_helper *fb_helper)
{
}

static inline int drm_fb_helper_init(struct drm_device *dev,
		       struct drm_fb_helper *helper)
{
	/* So drivers can use it to free the struct */
	helper->dev = dev;
	dev->fb_helper = helper;

	return 0;
}

static inline void drm_fb_helper_fini(struct drm_fb_helper *helper)
{
	if (helper && helper->dev)
		helper->dev->fb_helper = NULL;
}

static inline int drm_fb_helper_blank(int blank, struct fb_info *info)
{
	return 0;
}

static inline int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
					    struct fb_info *info)
{
	return 0;
}

static inline int drm_fb_helper_set_par(struct fb_info *info)
{
	return 0;
}

static inline int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
					  struct fb_info *info)
{
	return 0;
}

static inline int
drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
{
	return 0;
}

static inline struct fb_info *
drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
{
	return NULL;
}

static inline void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
{
}

static inline void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
{
}

static inline void
drm_fb_helper_fill_info(struct fb_info *info,
			struct drm_fb_helper *fb_helper,
			struct drm_fb_helper_surface_size *sizes)
{
}

static inline int drm_fb_helper_setcmap(struct fb_cmap *cmap,
					struct fb_info *info)
{
	return 0;
}

static inline int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
				      unsigned long arg)
{
	return 0;
}

static inline void drm_fb_helper_deferred_io(struct fb_info *info,
					     struct list_head *pagelist)
{
}

static inline void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper,
					     bool suspend)
{
}

static inline void
drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper, bool suspend)
{
}

static inline int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
{
	return 0;
}

static inline int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper)
{
	return 0;
}

static inline int drm_fb_helper_debug_enter(struct fb_info *info)
{
	return 0;
}

static inline int drm_fb_helper_debug_leave(struct fb_info *info)
{
	return 0;
}

static inline void drm_fb_helper_lastclose(struct drm_device *dev)
{
}

static inline void drm_fb_helper_output_poll_changed(struct drm_device *dev)
{
}
#endif

#endif