linux/drivers/gpu/drm/drm_fb_helper.c

/*
 * Copyright (c) 2006-2009 Red Hat Inc.
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <[email protected]>
 *
 * 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 <[email protected]>
 *      Jesse Barnes <[email protected]>
 */
#define pr_fmt(fmt)

#include <linux/console.h>
#include <linux/pci.h>
#include <linux/sysrq.h>
#include <linux/vga_switcheroo.h>

#include <drm/drm_atomic.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_print.h>
#include <drm/drm_vblank.h>

#include "drm_internal.h"

static bool drm_fbdev_emulation =;
module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600);
MODULE_PARM_DESC();

static int drm_fbdev_overalloc =;
module_param(drm_fbdev_overalloc, int, 0444);
MODULE_PARM_DESC();

/*
 * In order to keep user-space compatibility, we want in certain use-cases
 * to keep leaking the fbdev physical address to the user-space program
 * handling the fbdev buffer.
 *
 * This is a bad habit, essentially kept to support closed-source OpenGL
 * drivers that should really be moved into open-source upstream projects
 * instead of using legacy physical addresses in user space to communicate
 * with other out-of-tree kernel modules.
 *
 * This module_param *should* be removed as soon as possible and be
 * considered as a broken and legacy behaviour from a modern fbdev device.
 */
static bool drm_leak_fbdev_smem;
#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
module_param_unsafe(drm_leak_fbdev_smem, bool, 0600);
MODULE_PARM_DESC();
#endif

static LIST_HEAD(kernel_fb_helper_list);
static DEFINE_MUTEX(kernel_fb_helper_lock);

/**
 * DOC: fbdev helpers
 *
 * The fb helper functions are useful to provide an fbdev on top of a drm kernel
 * mode setting driver. They can be used mostly independently from the crtc
 * helper functions used by many drivers to implement the kernel mode setting
 * interfaces. Drivers that use one of the shared memory managers, TTM, SHMEM,
 * DMA, should instead use the corresponding fbdev emulation.
 *
 * Existing fbdev implementations should restore the fbdev console by using
 * drm_fb_helper_lastclose() as their &drm_driver.lastclose callback.
 * They should also notify the fb helper code from updates to the output
 * configuration by using drm_fb_helper_output_poll_changed() as their
 * &drm_mode_config_funcs.output_poll_changed callback. New implementations
 * of fbdev should be build on top of struct &drm_client_funcs, which handles
 * this automatically. Setting the old callbacks should be avoided.
 *
 * For suspend/resume consider using drm_mode_config_helper_suspend() and
 * drm_mode_config_helper_resume() which takes care of fbdev as well.
 *
 * All other functions exported by the fb helper library can be used to
 * implement the fbdev driver interface by the driver.
 *
 * It is possible, though perhaps somewhat tricky, to implement race-free
 * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
 * helper must be called first to initialize the minimum required to make
 * hotplug detection work. Drivers also need to make sure to properly set up
 * the &drm_mode_config.funcs member. After calling drm_kms_helper_poll_init()
 * it is safe to enable interrupts and start processing hotplug events. At the
 * same time, drivers should initialize all modeset objects such as CRTCs,
 * encoders and connectors. To finish up the fbdev helper initialization, the
 * drm_fb_helper_init() function is called. To probe for all attached displays
 * and set up an initial configuration using the detected hardware, drivers
 * should call drm_fb_helper_initial_config().
 *
 * If &drm_framebuffer_funcs.dirty is set, the
 * drm_fb_helper_{cfb,sys}_{write,fillrect,copyarea,imageblit} functions will
 * accumulate changes and schedule &drm_fb_helper.dirty_work to run right
 * away. This worker then calls the dirty() function ensuring that it will
 * always run in process context since the fb_*() function could be running in
 * atomic context. If drm_fb_helper_deferred_io() is used as the deferred_io
 * callback it will also schedule dirty_work with the damage collected from the
 * mmap page writes.
 */

static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
{}

/**
 * drm_fb_helper_debug_enter - implementation for &fb_ops.fb_debug_enter
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_debug_enter(struct fb_info *info)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_debug_leave - implementation for &fb_ops.fb_debug_leave
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_debug_leave(struct fb_info *info)
{}
EXPORT_SYMBOL();

static int
__drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
					    bool force)
{}

/**
 * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 *
 * This should be called from driver's drm &drm_driver.lastclose callback
 * when implementing an fbcon on top of kms using this helper. This ensures that
 * the user isn't greeted with a black screen when e.g. X dies.
 *
 * RETURNS:
 * Zero if everything went ok, negative error code otherwise.
 */
int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

#ifdef CONFIG_MAGIC_SYSRQ
/* emergency restore, don't bother with error reporting */
static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
{}

static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);

static void drm_fb_helper_sysrq(u8 dummy1)
{}

static const struct sysrq_key_op sysrq_drm_fb_helper_restore_op =;
#else
static const struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };
#endif

static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
{}

/**
 * drm_fb_helper_blank - implementation for &fb_ops.fb_blank
 * @blank: desired blanking state
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_blank(int blank, struct fb_info *info)
{}
EXPORT_SYMBOL();

static void drm_fb_helper_resume_worker(struct work_struct *work)
{}

static void drm_fb_helper_fb_dirty(struct drm_fb_helper *helper)
{}

static void drm_fb_helper_damage_work(struct work_struct *work)
{}

/**
 * drm_fb_helper_prepare - setup a drm_fb_helper structure
 * @dev: DRM device
 * @helper: driver-allocated fbdev helper structure to set up
 * @preferred_bpp: Preferred bits per pixel for the device.
 * @funcs: pointer to structure of functions associate with this helper
 *
 * Sets up the bare minimum to make the framebuffer helper usable. This is
 * useful to implement race-free initialization of the polling helpers.
 */
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)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_unprepare - clean up a drm_fb_helper structure
 * @fb_helper: driver-allocated fbdev helper structure to set up
 *
 * Cleans up the framebuffer helper. Inverse of drm_fb_helper_prepare().
 */
void drm_fb_helper_unprepare(struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_init - initialize a &struct drm_fb_helper
 * @dev: drm device
 * @fb_helper: driver-allocated fbdev helper structure to initialize
 *
 * This allocates the structures for the fbdev helper with the given limits.
 * Note that this won't yet touch the hardware (through the driver interfaces)
 * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
 * to allow driver writes more control over the exact init sequence.
 *
 * Drivers must call drm_fb_helper_prepare() before calling this function.
 *
 * RETURNS:
 * Zero if everything went ok, nonzero otherwise.
 */
int drm_fb_helper_init(struct drm_device *dev,
		       struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_alloc_info - allocate fb_info and some of its members
 * @fb_helper: driver-allocated fbdev helper
 *
 * A helper to alloc fb_info and the member cmap. Called by the driver
 * within the fb_probe fb_helper callback function. Drivers do not
 * need to release the allocated fb_info structure themselves, this is
 * automatically done when calling drm_fb_helper_fini().
 *
 * RETURNS:
 * fb_info pointer if things went okay, pointer containing error code
 * otherwise
 */
struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_release_info - release fb_info and its members
 * @fb_helper: driver-allocated fbdev helper
 *
 * A helper to release fb_info and the member cmap.  Drivers do not
 * need to release the allocated fb_info structure themselves, this is
 * automatically done when calling drm_fb_helper_fini().
 */
void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 *
 * A wrapper around unregister_framebuffer, to release the fb_info
 * framebuffer device. This must be called before releasing all resources for
 * @fb_helper by calling drm_fb_helper_fini().
 */
void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_fini - finialize a &struct drm_fb_helper
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 *
 * This cleans up all remaining resources associated with @fb_helper.
 */
void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

static void drm_fb_helper_add_damage_clip(struct drm_fb_helper *helper, u32 x, u32 y,
					  u32 width, u32 height)
{}

static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y,
				 u32 width, u32 height)
{}

/*
 * Convert memory region into area of scanlines and pixels per
 * scanline. The parameters off and len must not reach beyond
 * the end of the framebuffer.
 */
static void drm_fb_helper_memory_range_to_clip(struct fb_info *info, off_t off, size_t len,
					       struct drm_rect *clip)
{}

/* Don't use in new code. */
void drm_fb_helper_damage_range(struct fb_info *info, off_t off, size_t len)
{}
EXPORT_SYMBOL();

/* Don't use in new code. */
void drm_fb_helper_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_deferred_io() - fbdev deferred_io callback function
 * @info: fb_info struct pointer
 * @pagereflist: list of mmap framebuffer pages that have to be flushed
 *
 * This function is used as the &fb_deferred_io.deferred_io
 * callback function for flushing the fbdev mmap writes.
 */
void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagereflist)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_set_suspend - wrapper around fb_set_suspend
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 * @suspend: whether to suspend or resume
 *
 * A wrapper around fb_set_suspend implemented by fbdev core.
 * Use drm_fb_helper_set_suspend_unlocked() if you don't need to take
 * the lock yourself
 */
void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, bool suspend)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_set_suspend_unlocked - wrapper around fb_set_suspend that also
 *                                      takes the console lock
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 * @suspend: whether to suspend or resume
 *
 * A wrapper around fb_set_suspend() that takes the console lock. If the lock
 * isn't available on resume, a worker is tasked with waiting for the lock
 * to become available. The console lock can be pretty contented on resume
 * due to all the printk activity.
 *
 * This function can be called multiple times with the same state since
 * &fb_info.state is checked to see if fbdev is running or not before locking.
 *
 * Use drm_fb_helper_set_suspend() if you need to take the lock yourself.
 */
void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
					bool suspend)
{}
EXPORT_SYMBOL();

static int setcmap_pseudo_palette(struct fb_cmap *cmap, struct fb_info *info)
{}

static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
{}

static struct drm_property_blob *setcmap_new_gamma_lut(struct drm_crtc *crtc,
						       struct fb_cmap *cmap)
{}

static int setcmap_atomic(struct fb_cmap *cmap, struct fb_info *info)
{}

/**
 * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
 * @cmap: cmap to set
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_ioctl - legacy ioctl implementation
 * @info: fbdev registered by the helper
 * @cmd: ioctl command
 * @arg: ioctl argument
 *
 * A helper to implement the standard fbdev ioctl. Only
 * FBIO_WAITFORVSYNC is implemented for now.
 */
int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
			unsigned long arg)
{}
EXPORT_SYMBOL();

static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
				      const struct fb_var_screeninfo *var_2)
{}

static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var,
					 const struct drm_format_info *format)
{}

static void __fill_var(struct fb_var_screeninfo *var, struct fb_info *info,
		       struct drm_framebuffer *fb)
{}

/**
 * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
 * @var: screeninfo to check
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
			    struct fb_info *info)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_set_par - implementation for &fb_ops.fb_set_par
 * @info: fbdev registered by the helper
 *
 * This will let fbcon do the mode init and is called at initialization time by
 * the fbdev core when registering the driver, and later on through the hotplug
 * callback.
 */
int drm_fb_helper_set_par(struct fb_info *info)
{}
EXPORT_SYMBOL();

static void pan_set(struct drm_fb_helper *fb_helper, int x, int y)
{}

static int pan_display_atomic(struct fb_var_screeninfo *var,
			      struct fb_info *info)
{}

static int pan_display_legacy(struct fb_var_screeninfo *var,
			      struct fb_info *info)
{}

/**
 * drm_fb_helper_pan_display - implementation for &fb_ops.fb_pan_display
 * @var: updated screen information
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
			      struct fb_info *info)
{}
EXPORT_SYMBOL();

static uint32_t drm_fb_helper_find_format(struct drm_fb_helper *fb_helper, const uint32_t *formats,
					  size_t format_count, uint32_t bpp, uint32_t depth)
{}

static uint32_t drm_fb_helper_find_color_mode_format(struct drm_fb_helper *fb_helper,
						     const uint32_t *formats, size_t format_count,
						     unsigned int color_mode)
{}

static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
				      struct drm_fb_helper_surface_size *sizes)
{}

static int drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
				    struct drm_fb_helper_surface_size *sizes)
{}

/*
 * Allocates the backing storage and sets up the fbdev info structure through
 * the ->fb_probe callback.
 */
static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
{}

static void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
				   bool is_color_indexed)
{}

static void drm_fb_helper_fill_var(struct fb_info *info,
				   struct drm_fb_helper *fb_helper,
				   uint32_t fb_width, uint32_t fb_height)
{}

/**
 * drm_fb_helper_fill_info - initializes fbdev information
 * @info: fbdev instance to set up
 * @fb_helper: fb helper instance to use as template
 * @sizes: describes fbdev size and scanout surface size
 *
 * Sets up the variable and fixed fbdev metainformation from the given fb helper
 * instance and the drm framebuffer allocated in &drm_fb_helper.fb.
 *
 * Drivers should call this (or their equivalent setup code) from their
 * &drm_fb_helper_funcs.fb_probe callback after having allocated the fbdev
 * backing storage framebuffer.
 */
void drm_fb_helper_fill_info(struct fb_info *info,
			     struct drm_fb_helper *fb_helper,
			     struct drm_fb_helper_surface_size *sizes)
{}
EXPORT_SYMBOL();

/*
 * This is a continuation of drm_setup_crtcs() that sets up anything related
 * to the framebuffer. During initialization, drm_setup_crtcs() is called before
 * the framebuffer has been allocated (fb_helper->fb and fb_helper->info).
 * So, any setup that touches those fields needs to be done here instead of in
 * drm_setup_crtcs().
 */
static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
{}

/* Note: Drops fb_helper->lock before returning. */
static int
__drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
{}

/**
 * drm_fb_helper_initial_config - setup a sane initial connector configuration
 * @fb_helper: fb_helper device struct
 *
 * Scans the CRTCs and connectors and tries to put together an initial setup.
 * At the moment, this is a cloned configuration across all heads with
 * a new framebuffer object as the backing store.
 *
 * Note that this also registers the fbdev and so allows userspace to call into
 * the driver through the fbdev interfaces.
 *
 * This function will call down into the &drm_fb_helper_funcs.fb_probe callback
 * to let the driver allocate and initialize the fbdev info structure and the
 * drm framebuffer used to back the fbdev. drm_fb_helper_fill_info() is provided
 * as a helper to setup simple default values for the fbdev info structure.
 *
 * HANG DEBUGGING:
 *
 * When you have fbcon support built-in or already loaded, this function will do
 * a full modeset to setup the fbdev console. Due to locking misdesign in the
 * VT/fbdev subsystem that entire modeset sequence has to be done while holding
 * console_lock. Until console_unlock is called no dmesg lines will be sent out
 * to consoles, not even serial console. This means when your driver crashes,
 * you will see absolutely nothing else but a system stuck in this function,
 * with no further output. Any kind of printk() you place within your own driver
 * or in the drm core modeset code will also never show up.
 *
 * Standard debug practice is to run the fbcon setup without taking the
 * console_lock as a hack, to be able to see backtraces and crashes on the
 * serial line. This can be done by setting the fb.lockless_register_fb=1 kernel
 * cmdline option.
 *
 * The other option is to just disable fbdev emulation since very likely the
 * first modeset from userspace will crash in the same way, and is even easier
 * to debug. This can be done by setting the drm_kms_helper.fbdev_emulation=0
 * kernel cmdline option.
 *
 * RETURNS:
 * Zero if everything went ok, nonzero otherwise.
 */
int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_hotplug_event - respond to a hotplug notification by
 *                               probing all the outputs attached to the fb
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 *
 * Scan the connectors attached to the fb_helper and try to put together a
 * setup after notification of a change in output configuration.
 *
 * Called at runtime, takes the mode config locks to be able to check/change the
 * modeset configuration. Must be run from process context (which usually means
 * either the output polling work or a work item launched from the driver's
 * hotplug interrupt).
 *
 * Note that drivers may call this even before calling
 * drm_fb_helper_initial_config but only after drm_fb_helper_init. This allows
 * for a race-free fbcon setup and will make sure that the fbdev emulation will
 * not miss any hotplug events.
 *
 * RETURNS:
 * 0 on success and a non-zero error code otherwise.
 */
int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_lastclose - DRM driver lastclose helper for fbdev emulation
 * @dev: DRM device
 *
 * This function can be used as the &drm_driver->lastclose callback for drivers
 * that only need to call drm_fb_helper_restore_fbdev_mode_unlocked().
 */
void drm_fb_helper_lastclose(struct drm_device *dev)
{}
EXPORT_SYMBOL();

/**
 * drm_fb_helper_output_poll_changed - DRM mode config \.output_poll_changed
 *                                     helper for fbdev emulation
 * @dev: DRM device
 *
 * This function can be used as the
 * &drm_mode_config_funcs.output_poll_changed callback for drivers that only
 * need to call drm_fbdev.hotplug_event().
 */
void drm_fb_helper_output_poll_changed(struct drm_device *dev)
{}
EXPORT_SYMBOL();