Merge branch 'etnaviv/fixes' of https://git.pengutronix.de/git/lst/linux into drm...

[sfrench/cifs-2.6.git] / include / drm / drm_crtc.h

/*
 * Copyright © 2006 Keith Packard
 * Copyright © 2007-2008 Dave Airlie
 * Copyright © 2007-2008 Intel Corporation
 *   Jesse Barnes <jesse.barnes@intel.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
#ifndef __DRM_CRTC_H__
#define __DRM_CRTC_H__

#include <linux/i2c.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/fb.h>
#include <linux/hdmi.h>
#include <linux/media-bus-format.h>
#include <uapi/drm/drm_mode.h>
#include <uapi/drm/drm_fourcc.h>
#include <drm/drm_modeset_lock.h>
#include <drm/drm_rect.h>
#include <drm/drm_mode_object.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_modes.h>
#include <drm/drm_connector.h>
#include <drm/drm_property.h>
#include <drm/drm_bridge.h>
#include <drm/drm_edid.h>
#include <drm/drm_plane.h>
#include <drm/drm_blend.h>
#include <drm/drm_color_mgmt.h>
#include <drm/drm_debugfs_crc.h>
#include <drm/drm_mode_config.h>

struct drm_device;
struct drm_mode_set;
struct drm_file;
struct drm_clip_rect;
struct drm_printer;
struct device_node;
struct dma_fence;
struct edid;

static inline int64_t U642I64(uint64_t val)
{
        return (int64_t)*((int64_t *)&val);
}
static inline uint64_t I642U64(int64_t val)
{
        return (uint64_t)*((uint64_t *)&val);
}

struct drm_crtc;
struct drm_pending_vblank_event;
struct drm_plane;
struct drm_bridge;
struct drm_atomic_state;

struct drm_crtc_helper_funcs;
struct drm_plane_helper_funcs;

/**
 * struct drm_crtc_state - mutable CRTC state
 *
 * Note that the distinction between @enable and @active is rather subtile:
 * Flipping @active while @enable is set without changing anything else may
 * never return in a failure from the &drm_mode_config_funcs.atomic_check
 * callback. Userspace assumes that a DPMS On will always succeed. In other
 * words: @enable controls resource assignment, @active controls the actual
 * hardware state.
 *
 * The three booleans active_changed, connectors_changed and mode_changed are
 * intended to indicate whether a full modeset is needed, rather than strictly
 * describing what has changed in a commit. See also:
 * drm_atomic_crtc_needs_modeset()
 *
 * WARNING: Transitional helpers (like drm_helper_crtc_mode_set() or
 * drm_helper_crtc_mode_set_base()) do not maintain many of the derived control
 * state like @plane_mask so drivers not converted over to atomic helpers should
 * not rely on these being accurate!
 */
struct drm_crtc_state {
        /** @crtc: backpointer to the CRTC */
        struct drm_crtc *crtc;

        /**
         * @enable: Whether the CRTC should be enabled, gates all other state.
         * This controls reservations of shared resources. Actual hardware state
         * is controlled by @active.
         */
        bool enable;

        /**
         * @active: Whether the CRTC is actively displaying (used for DPMS).
         * Implies that @enable is set. The driver must not release any shared
         * resources if @active is set to false but @enable still true, because
         * userspace expects that a DPMS ON always succeeds.
         *
         * Hence drivers must not consult @active in their various
         * &drm_mode_config_funcs.atomic_check callback to reject an atomic
         * commit. They can consult it to aid in the computation of derived
         * hardware state, since even in the DPMS OFF state the display hardware
         * should be as much powered down as when the CRTC is completely
         * disabled through setting @enable to false.
         */
        bool active;

        /**
         * @planes_changed: Planes on this crtc are updated. Used by the atomic
         * helpers and drivers to steer the atomic commit control flow.
         */
        bool planes_changed : 1;

        /**
         * @mode_changed: @mode or @enable has been changed. Used by the atomic
         * helpers and drivers to steer the atomic commit control flow. See also
         * drm_atomic_crtc_needs_modeset().
         *
         * Drivers are supposed to set this for any CRTC state changes that
         * require a full modeset. They can also reset it to false if e.g. a
         * @mode change can be done without a full modeset by only changing
         * scaler settings.
         */
        bool mode_changed : 1;

        /**
         * @active_changed: @active has been toggled. Used by the atomic
         * helpers and drivers to steer the atomic commit control flow. See also
         * drm_atomic_crtc_needs_modeset().
         */
        bool active_changed : 1;

        /**
         * @connectors_changed: Connectors to this crtc have been updated,
         * either in their state or routing. Used by the atomic
         * helpers and drivers to steer the atomic commit control flow. See also
         * drm_atomic_crtc_needs_modeset().
         *
         * Drivers are supposed to set this as-needed from their own atomic
         * check code, e.g. from &drm_encoder_helper_funcs.atomic_check
         */
        bool connectors_changed : 1;
        /**
         * @zpos_changed: zpos values of planes on this crtc have been updated.
         * Used by the atomic helpers and drivers to steer the atomic commit
         * control flow.
         */
        bool zpos_changed : 1;
        /**
         * @color_mgmt_changed: Color management properties have changed
         * (@gamma_lut, @degamma_lut or @ctm). Used by the atomic helpers and
         * drivers to steer the atomic commit control flow.
         */
        bool color_mgmt_changed : 1;

        /**
         * @no_vblank:
         *
         * Reflects the ability of a CRTC to send VBLANK events. This state
         * usually depends on the pipeline configuration, and the main usuage
         * is CRTCs feeding a writeback connector operating in oneshot mode.
         * In this case the VBLANK event is only generated when a job is queued
         * to the writeback connector, and we want the core to fake VBLANK
         * events when this part of the pipeline hasn't changed but others had
         * or when the CRTC and connectors are being disabled.
         *
         * __drm_atomic_helper_crtc_duplicate_state() will not reset the value
         * from the current state, the CRTC driver is then responsible for
         * updating this field when needed.
         *
         * Note that the combination of &drm_crtc_state.event == NULL and
         * &drm_crtc_state.no_blank == true is valid and usually used when the
         * writeback connector attached to the CRTC has a new job queued. In
         * this case the driver will send the VBLANK event on its own when the
         * writeback job is complete.
         */
        bool no_vblank : 1;

        /**
         * @plane_mask: Bitmask of drm_plane_mask(plane) of planes attached to
         * this CRTC.
         */
        u32 plane_mask;

        /**
         * @connector_mask: Bitmask of drm_connector_mask(connector) of
         * connectors attached to this CRTC.
         */
        u32 connector_mask;

        /**
         * @encoder_mask: Bitmask of drm_encoder_mask(encoder) of encoders
         * attached to this CRTC.
         */
        u32 encoder_mask;

        /**
         * @adjusted_mode:
         *
         * Internal display timings which can be used by the driver to handle
         * differences between the mode requested by userspace in @mode and what
         * is actually programmed into the hardware.
         *
         * For drivers using &drm_bridge, this stores hardware display timings
         * used between the CRTC and the first bridge. For other drivers, the
         * meaning of the adjusted_mode field is purely driver implementation
         * defined information, and will usually be used to store the hardware
         * display timings used between the CRTC and encoder blocks.
         */
        struct drm_display_mode adjusted_mode;

        /**
         * @mode:
         *
         * Display timings requested by userspace. The driver should try to
         * match the refresh rate as close as possible (but note that it's
         * undefined what exactly is close enough, e.g. some of the HDMI modes
         * only differ in less than 1% of the refresh rate). The active width
         * and height as observed by userspace for positioning planes must match
         * exactly.
         *
         * For external connectors where the sink isn't fixed (like with a
         * built-in panel), this mode here should match the physical mode on the
         * wire to the last details (i.e. including sync polarities and
         * everything).
         */
        struct drm_display_mode mode;

        /**
         * @mode_blob: &drm_property_blob for @mode, for exposing the mode to
         * atomic userspace.
         */
        struct drm_property_blob *mode_blob;

        /**
         * @degamma_lut:
         *
         * Lookup table for converting framebuffer pixel data before apply the
         * color conversion matrix @ctm. See drm_crtc_enable_color_mgmt(). The
         * blob (if not NULL) is an array of &struct drm_color_lut.
         */
        struct drm_property_blob *degamma_lut;

        /**
         * @ctm:
         *
         * Color transformation matrix. See drm_crtc_enable_color_mgmt(). The
         * blob (if not NULL) is a &struct drm_color_ctm.
         */
        struct drm_property_blob *ctm;

        /**
         * @gamma_lut:
         *
         * Lookup table for converting pixel data after the color conversion
         * matrix @ctm.  See drm_crtc_enable_color_mgmt(). The blob (if not
         * NULL) is an array of &struct drm_color_lut.
         */
        struct drm_property_blob *gamma_lut;

        /**
         * @target_vblank:
         *
         * Target vertical blank period when a page flip
         * should take effect.
         */
        u32 target_vblank;

        /**
         * @pageflip_flags:
         *
         * DRM_MODE_PAGE_FLIP_* flags, as passed to the page flip ioctl.
         * Zero in any other case.
         */
        u32 pageflip_flags;

        /**
         * @event:
         *
         * Optional pointer to a DRM event to signal upon completion of the
         * state update. The driver must send out the event when the atomic
         * commit operation completes. There are two cases:
         *
         *  - The event is for a CRTC which is being disabled through this
         *    atomic commit. In that case the event can be send out any time
         *    after the hardware has stopped scanning out the current
         *    framebuffers. It should contain the timestamp and counter for the
         *    last vblank before the display pipeline was shut off. The simplest
         *    way to achieve that is calling drm_crtc_send_vblank_event()
         *    somewhen after drm_crtc_vblank_off() has been called.
         *
         *  - For a CRTC which is enabled at the end of the commit (even when it
         *    undergoes an full modeset) the vblank timestamp and counter must
         *    be for the vblank right before the first frame that scans out the
         *    new set of buffers. Again the event can only be sent out after the
         *    hardware has stopped scanning out the old buffers.
         *
         *  - Events for disabled CRTCs are not allowed, and drivers can ignore
         *    that case.
         *
         * This can be handled by the drm_crtc_send_vblank_event() function,
         * which the driver should call on the provided event upon completion of
         * the atomic commit. Note that if the driver supports vblank signalling
         * and timestamping the vblank counters and timestamps must agree with
         * the ones returned from page flip events. With the current vblank
         * helper infrastructure this can be achieved by holding a vblank
         * reference while the page flip is pending, acquired through
         * drm_crtc_vblank_get() and released with drm_crtc_vblank_put().
         * Drivers are free to implement their own vblank counter and timestamp
         * tracking though, e.g. if they have accurate timestamp registers in
         * hardware.
         *
         * For hardware which supports some means to synchronize vblank
         * interrupt delivery with committing display state there's also
         * drm_crtc_arm_vblank_event(). See the documentation of that function
         * for a detailed discussion of the constraints it needs to be used
         * safely.
         *
         * If the device can't notify of flip completion in a race-free way
         * at all, then the event should be armed just after the page flip is
         * committed. In the worst case the driver will send the event to
         * userspace one frame too late. This doesn't allow for a real atomic
         * update, but it should avoid tearing.
         */
        struct drm_pending_vblank_event *event;

        /**
         * @commit:
         *
         * This tracks how the commit for this update proceeds through the
         * various phases. This is never cleared, except when we destroy the
         * state, so that subsequent commits can synchronize with previous ones.
         */
        struct drm_crtc_commit *commit;

        /** @state: backpointer to global drm_atomic_state */
        struct drm_atomic_state *state;
};

/**
 * struct drm_crtc_funcs - control CRTCs for a given device
 *
 * The drm_crtc_funcs structure is the central CRTC management structure
 * in the DRM.  Each CRTC controls one or more connectors (note that the name
 * CRTC is simply historical, a CRTC may control LVDS, VGA, DVI, TV out, etc.
 * connectors, not just CRTs).
 *
 * Each driver is responsible for filling out this structure at startup time,
 * in addition to providing other modesetting features, like i2c and DDC
 * bus accessors.
 */
struct drm_crtc_funcs {
        /**
         * @reset:
         *
         * Reset CRTC hardware and software state to off. This function isn't
         * called by the core directly, only through drm_mode_config_reset().
         * It's not a helper hook only for historical reasons.
         *
         * Atomic drivers can use drm_atomic_helper_crtc_reset() to reset
         * atomic state using this hook.
         */
        void (*reset)(struct drm_crtc *crtc);

        /**
         * @cursor_set:
         *
         * Update the cursor image. The cursor position is relative to the CRTC
         * and can be partially or fully outside of the visible area.
         *
         * Note that contrary to all other KMS functions the legacy cursor entry
         * points don't take a framebuffer object, but instead take directly a
         * raw buffer object id from the driver's buffer manager (which is
         * either GEM or TTM for current drivers).
         *
         * This entry point is deprecated, drivers should instead implement
         * universal plane support and register a proper cursor plane using
         * drm_crtc_init_with_planes().
         *
         * This callback is optional
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*cursor_set)(struct drm_crtc *crtc, struct drm_file *file_priv,
                          uint32_t handle, uint32_t width, uint32_t height);

        /**
         * @cursor_set2:
         *
         * Update the cursor image, including hotspot information. The hotspot
         * must not affect the cursor position in CRTC coordinates, but is only
         * meant as a hint for virtualized display hardware to coordinate the
         * guests and hosts cursor position. The cursor hotspot is relative to
         * the cursor image. Otherwise this works exactly like @cursor_set.
         *
         * This entry point is deprecated, drivers should instead implement
         * universal plane support and register a proper cursor plane using
         * drm_crtc_init_with_planes().
         *
         * This callback is optional.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*cursor_set2)(struct drm_crtc *crtc, struct drm_file *file_priv,
                           uint32_t handle, uint32_t width, uint32_t height,
                           int32_t hot_x, int32_t hot_y);

        /**
         * @cursor_move:
         *
         * Update the cursor position. The cursor does not need to be visible
         * when this hook is called.
         *
         * This entry point is deprecated, drivers should instead implement
         * universal plane support and register a proper cursor plane using
         * drm_crtc_init_with_planes().
         *
         * This callback is optional.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*cursor_move)(struct drm_crtc *crtc, int x, int y);

        /**
         * @gamma_set:
         *
         * Set gamma on the CRTC.
         *
         * This callback is optional.
         *
         * Atomic drivers who want to support gamma tables should implement the
         * atomic color management support, enabled by calling
         * drm_crtc_enable_color_mgmt(), which then supports the legacy gamma
         * interface through the drm_atomic_helper_legacy_gamma_set()
         * compatibility implementation.
         */
        int (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
                         uint32_t size,
                         struct drm_modeset_acquire_ctx *ctx);

        /**
         * @destroy:
         *
         * Clean up plane resources. This is only called at driver unload time
         * through drm_mode_config_cleanup() since a CRTC cannot be hotplugged
         * in DRM.
         */
        void (*destroy)(struct drm_crtc *crtc);

        /**
         * @set_config:
         *
         * This is the main legacy entry point to change the modeset state on a
         * CRTC. All the details of the desired configuration are passed in a
         * &struct drm_mode_set - see there for details.
         *
         * Drivers implementing atomic modeset should use
         * drm_atomic_helper_set_config() to implement this hook.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*set_config)(struct drm_mode_set *set,
                          struct drm_modeset_acquire_ctx *ctx);

        /**
         * @page_flip:
         *
         * Legacy entry point to schedule a flip to the given framebuffer.
         *
         * Page flipping is a synchronization mechanism that replaces the frame
         * buffer being scanned out by the CRTC with a new frame buffer during
         * vertical blanking, avoiding tearing (except when requested otherwise
         * through the DRM_MODE_PAGE_FLIP_ASYNC flag). When an application
         * requests a page flip the DRM core verifies that the new frame buffer
         * is large enough to be scanned out by the CRTC in the currently
         * configured mode and then calls this hook with a pointer to the new
         * frame buffer.
         *
         * The driver must wait for any pending rendering to the new framebuffer
         * to complete before executing the flip. It should also wait for any
         * pending rendering from other drivers if the underlying buffer is a
         * shared dma-buf.
         *
         * An application can request to be notified when the page flip has
         * completed. The drm core will supply a &struct drm_event in the event
         * parameter in this case. This can be handled by the
         * drm_crtc_send_vblank_event() function, which the driver should call on
         * the provided event upon completion of the flip. Note that if
         * the driver supports vblank signalling and timestamping the vblank
         * counters and timestamps must agree with the ones returned from page
         * flip events. With the current vblank helper infrastructure this can
         * be achieved by holding a vblank reference while the page flip is
         * pending, acquired through drm_crtc_vblank_get() and released with
         * drm_crtc_vblank_put(). Drivers are free to implement their own vblank
         * counter and timestamp tracking though, e.g. if they have accurate
         * timestamp registers in hardware.
         *
         * This callback is optional.
         *
         * NOTE:
         *
         * Very early versions of the KMS ABI mandated that the driver must
         * block (but not reject) any rendering to the old framebuffer until the
         * flip operation has completed and the old framebuffer is no longer
         * visible. This requirement has been lifted, and userspace is instead
         * expected to request delivery of an event and wait with recycling old
         * buffers until such has been received.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure. Note that if a
         * page flip operation is already pending the callback should return
         * -EBUSY. Pageflips on a disabled CRTC (either by setting a NULL mode
         * or just runtime disabled through DPMS respectively the new atomic
         * "ACTIVE" state) should result in an -EINVAL error code. Note that
         * drm_atomic_helper_page_flip() checks this already for atomic drivers.
         */
        int (*page_flip)(struct drm_crtc *crtc,
                         struct drm_framebuffer *fb,
                         struct drm_pending_vblank_event *event,
                         uint32_t flags,
                         struct drm_modeset_acquire_ctx *ctx);

        /**
         * @page_flip_target:
         *
         * Same as @page_flip but with an additional parameter specifying the
         * absolute target vertical blank period (as reported by
         * drm_crtc_vblank_count()) when the flip should take effect.
         *
         * Note that the core code calls drm_crtc_vblank_get before this entry
         * point, and will call drm_crtc_vblank_put if this entry point returns
         * any non-0 error code. It's the driver's responsibility to call
         * drm_crtc_vblank_put after this entry point returns 0, typically when
         * the flip completes.
         */
        int (*page_flip_target)(struct drm_crtc *crtc,
                                struct drm_framebuffer *fb,
                                struct drm_pending_vblank_event *event,
                                uint32_t flags, uint32_t target,
                                struct drm_modeset_acquire_ctx *ctx);

        /**
         * @set_property:
         *
         * This is the legacy entry point to update a property attached to the
         * CRTC.
         *
         * This callback is optional if the driver does not support any legacy
         * driver-private properties. For atomic drivers it is not used because
         * property handling is done entirely in the DRM core.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*set_property)(struct drm_crtc *crtc,
                            struct drm_property *property, uint64_t val);

        /**
         * @atomic_duplicate_state:
         *
         * Duplicate the current atomic state for this CRTC and return it.
         * The core and helpers guarantee that any atomic state duplicated with
         * this hook and still owned by the caller (i.e. not transferred to the
         * driver by calling &drm_mode_config_funcs.atomic_commit) will be
         * cleaned up by calling the @atomic_destroy_state hook in this
         * structure.
         *
         * This callback is mandatory for atomic drivers.
         *
         * Atomic drivers which don't subclass &struct drm_crtc_state should use
         * drm_atomic_helper_crtc_duplicate_state(). Drivers that subclass the
         * state structure to extend it with driver-private state should use
         * __drm_atomic_helper_crtc_duplicate_state() to make sure shared state is
         * duplicated in a consistent fashion across drivers.
         *
         * It is an error to call this hook before &drm_crtc.state has been
         * initialized correctly.
         *
         * NOTE:
         *
         * If the duplicate state references refcounted resources this hook must
         * acquire a reference for each of them. The driver must release these
         * references again in @atomic_destroy_state.
         *
         * RETURNS:
         *
         * Duplicated atomic state or NULL when the allocation failed.
         */
        struct drm_crtc_state *(*atomic_duplicate_state)(struct drm_crtc *crtc);

        /**
         * @atomic_destroy_state:
         *
         * Destroy a state duplicated with @atomic_duplicate_state and release
         * or unreference all resources it references
         *
         * This callback is mandatory for atomic drivers.
         */
        void (*atomic_destroy_state)(struct drm_crtc *crtc,
                                     struct drm_crtc_state *state);

        /**
         * @atomic_set_property:
         *
         * Decode a driver-private property value and store the decoded value
         * into the passed-in state structure. Since the atomic core decodes all
         * standardized properties (even for extensions beyond the core set of
         * properties which might not be implemented by all drivers) this
         * requires drivers to subclass the state structure.
         *
         * Such driver-private properties should really only be implemented for
         * truly hardware/vendor specific state. Instead it is preferred to
         * standardize atomic extension and decode the properties used to expose
         * such an extension in the core.
         *
         * Do not call this function directly, use
         * drm_atomic_crtc_set_property() instead.
         *
         * This callback is optional if the driver does not support any
         * driver-private atomic properties.
         *
         * NOTE:
         *
         * This function is called in the state assembly phase of atomic
         * modesets, which can be aborted for any reason (including on
         * userspace's request to just check whether a configuration would be
         * possible). Drivers MUST NOT touch any persistent state (hardware or
         * software) or data structures except the passed in @state parameter.
         *
         * Also since userspace controls in which order properties are set this
         * function must not do any input validation (since the state update is
         * incomplete and hence likely inconsistent). Instead any such input
         * validation must be done in the various atomic_check callbacks.
         *
         * RETURNS:
         *
         * 0 if the property has been found, -EINVAL if the property isn't
         * implemented by the driver (which should never happen, the core only
         * asks for properties attached to this CRTC). No other validation is
         * allowed by the driver. The core already checks that the property
         * value is within the range (integer, valid enum value, ...) the driver
         * set when registering the property.
         */
        int (*atomic_set_property)(struct drm_crtc *crtc,
                                   struct drm_crtc_state *state,
                                   struct drm_property *property,
                                   uint64_t val);
        /**
         * @atomic_get_property:
         *
         * Reads out the decoded driver-private property. This is used to
         * implement the GETCRTC IOCTL.
         *
         * Do not call this function directly, use
         * drm_atomic_crtc_get_property() instead.
         *
         * This callback is optional if the driver does not support any
         * driver-private atomic properties.
         *
         * RETURNS:
         *
         * 0 on success, -EINVAL if the property isn't implemented by the
         * driver (which should never happen, the core only asks for
         * properties attached to this CRTC).
         */
        int (*atomic_get_property)(struct drm_crtc *crtc,
                                   const struct drm_crtc_state *state,
                                   struct drm_property *property,
                                   uint64_t *val);

        /**
         * @late_register:
         *
         * This optional hook can be used to register additional userspace
         * interfaces attached to the crtc like debugfs interfaces.
         * It is called late in the driver load sequence from drm_dev_register().
         * Everything added from this callback should be unregistered in
         * the early_unregister callback.
         *
         * Returns:
         *
         * 0 on success, or a negative error code on failure.
         */
        int (*late_register)(struct drm_crtc *crtc);

        /**
         * @early_unregister:
         *
         * This optional hook should be used to unregister the additional
         * userspace interfaces attached to the crtc from
         * @late_register. It is called from drm_dev_unregister(),
         * early in the driver unload sequence to disable userspace access
         * before data structures are torndown.
         */
        void (*early_unregister)(struct drm_crtc *crtc);

        /**
         * @set_crc_source:
         *
         * Changes the source of CRC checksums of frames at the request of
         * userspace, typically for testing purposes. The sources available are
         * specific of each driver and a %NULL value indicates that CRC
         * generation is to be switched off.
         *
         * When CRC generation is enabled, the driver should call
         * drm_crtc_add_crc_entry() at each frame, providing any information
         * that characterizes the frame contents in the crcN arguments, as
         * provided from the configured source. Drivers must accept an "auto"
         * source name that will select a default source for this CRTC.
         *
         * Note that "auto" can depend upon the current modeset configuration,
         * e.g. it could pick an encoder or output specific CRC sampling point.
         *
         * This callback is optional if the driver does not support any CRC
         * generation functionality.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*set_crc_source)(struct drm_crtc *crtc, const char *source);
        /**
         * @verify_crc_source:
         *
         * verifies the source of CRC checksums of frames before setting the
         * source for CRC and during crc open. Source parameter can be NULL
         * while disabling crc source.
         *
         * This callback is optional if the driver does not support any CRC
         * generation functionality.
         *
         * RETURNS:
         *
         * 0 on success or a negative error code on failure.
         */
        int (*verify_crc_source)(struct drm_crtc *crtc, const char *source,
                                 size_t *values_cnt);
        /**
         * @get_crc_sources:
         *
         * Driver callback for getting a list of all the available sources for
         * CRC generation. This callback depends upon verify_crc_source, So
         * verify_crc_source callback should be implemented before implementing
         * this. Driver can pass full list of available crc sources, this
         * callback does the verification on each crc-source before passing it
         * to userspace.
         *
         * This callback is optional if the driver does not support exporting of
         * possible CRC sources list.
         *
         * RETURNS:
         *
         * a constant character pointer to the list of all the available CRC
         * sources. On failure driver should return NULL. count should be
         * updated with number of sources in list. if zero we don't process any
         * source from the list.
         */
        const char *const *(*get_crc_sources)(struct drm_crtc *crtc,
                                              size_t *count);

        /**
         * @atomic_print_state:
         *
         * If driver subclasses &struct drm_crtc_state, it should implement
         * this optional hook for printing additional driver specific state.
         *
         * Do not call this directly, use drm_atomic_crtc_print_state()
         * instead.
         */
        void (*atomic_print_state)(struct drm_printer *p,
                                   const struct drm_crtc_state *state);

        /**
         * @get_vblank_counter:
         *
         * Driver callback for fetching a raw hardware vblank counter for the
         * CRTC. It's meant to be used by new drivers as the replacement of
         * &drm_driver.get_vblank_counter hook.
         *
         * This callback is optional. If a device doesn't have a hardware
         * counter, the driver can simply leave the hook as NULL. The DRM core
         * will account for missed vblank events while interrupts where disabled
         * based on system timestamps.
         *
         * Wraparound handling and loss of events due to modesetting is dealt
         * with in the DRM core code, as long as drivers call
         * drm_crtc_vblank_off() and drm_crtc_vblank_on() when disabling or
         * enabling a CRTC.
         *
         * See also &drm_device.vblank_disable_immediate and
         * &drm_device.max_vblank_count.
         *
         * Returns:
         *
         * Raw vblank counter value.
         */
        u32 (*get_vblank_counter)(struct drm_crtc *crtc);

        /**
         * @enable_vblank:
         *
         * Enable vblank interrupts for the CRTC. It's meant to be used by
         * new drivers as the replacement of &drm_driver.enable_vblank hook.
         *
         * Returns:
         *
         * Zero on success, appropriate errno if the vblank interrupt cannot
         * be enabled.
         */
        int (*enable_vblank)(struct drm_crtc *crtc);

        /**
         * @disable_vblank:
         *
         * Disable vblank interrupts for the CRTC. It's meant to be used by
         * new drivers as the replacement of &drm_driver.disable_vblank hook.
         */
        void (*disable_vblank)(struct drm_crtc *crtc);
};

/**
 * struct drm_crtc - central CRTC control structure
 *
 * Each CRTC may have one or more connectors associated with it.  This structure
 * allows the CRTC to be controlled.
 */
struct drm_crtc {
        /** @dev: parent DRM device */
        struct drm_device *dev;
        /** @port: OF node used by drm_of_find_possible_crtcs(). */
        struct device_node *port;
        /**
         * @head:
         *
         * List of all CRTCs on @dev, linked from &drm_mode_config.crtc_list.
         * Invariant over the lifetime of @dev and therefore does not need
         * locking.
         */
        struct list_head head;

        /** @name: human readable name, can be overwritten by the driver */
        char *name;

        /**
         * @mutex:
         *
         * This provides a read lock for the overall CRTC state (mode, dpms
         * state, ...) and a write lock for everything which can be update
         * without a full modeset (fb, cursor data, CRTC properties ...). A full
         * modeset also need to grab &drm_mode_config.connection_mutex.
         *
         * For atomic drivers specifically this protects @state.
         */
        struct drm_modeset_lock mutex;

        /** @base: base KMS object for ID tracking etc. */
        struct drm_mode_object base;

        /**
         * @primary:
         * Primary plane for this CRTC. Note that this is only
         * relevant for legacy IOCTL, it specifies the plane implicitly used by
         * the SETCRTC and PAGE_FLIP IOCTLs. It does not have any significance
         * beyond that.
         */
        struct drm_plane *primary;

        /**
         * @cursor:
         * Cursor plane for this CRTC. Note that this is only relevant for
         * legacy IOCTL, it specifies the plane implicitly used by the SETCURSOR
         * and SETCURSOR2 IOCTLs. It does not have any significance
         * beyond that.
         */
        struct drm_plane *cursor;

        /**
         * @index: Position inside the mode_config.list, can be used as an array
         * index. It is invariant over the lifetime of the CRTC.
         */
        unsigned index;

        /**
         * @cursor_x: Current x position of the cursor, used for universal
         * cursor planes because the SETCURSOR IOCTL only can update the
         * framebuffer without supplying the coordinates. Drivers should not use
         * this directly, atomic drivers should look at &drm_plane_state.crtc_x
         * of the cursor plane instead.
         */
        int cursor_x;
        /**
         * @cursor_y: Current y position of the cursor, used for universal
         * cursor planes because the SETCURSOR IOCTL only can update the
         * framebuffer without supplying the coordinates. Drivers should not use
         * this directly, atomic drivers should look at &drm_plane_state.crtc_y
         * of the cursor plane instead.
         */
        int cursor_y;

        /**
         * @enabled:
         *
         * Is this CRTC enabled? Should only be used by legacy drivers, atomic
         * drivers should instead consult &drm_crtc_state.enable and
         * &drm_crtc_state.active. Atomic drivers can update this by calling
         * drm_atomic_helper_update_legacy_modeset_state().
         */
        bool enabled;

        /**
         * @mode:
         *
         * Current mode timings. Should only be used by legacy drivers, atomic
         * drivers should instead consult &drm_crtc_state.mode. Atomic drivers
         * can update this by calling
         * drm_atomic_helper_update_legacy_modeset_state().
         */
        struct drm_display_mode mode;

        /**
         * @hwmode:
         *
         * Programmed mode in hw, after adjustments for encoders, crtc, panel
         * scaling etc. Should only be used by legacy drivers, for high
         * precision vblank timestamps in
         * drm_calc_vbltimestamp_from_scanoutpos().
         *
         * Note that atomic drivers should not use this, but instead use
         * &drm_crtc_state.adjusted_mode. And for high-precision timestamps
         * drm_calc_vbltimestamp_from_scanoutpos() used &drm_vblank_crtc.hwmode,
         * which is filled out by calling drm_calc_timestamping_constants().
         */
        struct drm_display_mode hwmode;

        /**
         * @x:
         * x position on screen. Should only be used by legacy drivers, atomic
         * drivers should look at &drm_plane_state.crtc_x of the primary plane
         * instead. Updated by calling
         * drm_atomic_helper_update_legacy_modeset_state().
         */
        int x;
        /**
         * @y:
         * y position on screen. Should only be used by legacy drivers, atomic
         * drivers should look at &drm_plane_state.crtc_y of the primary plane
         * instead. Updated by calling
         * drm_atomic_helper_update_legacy_modeset_state().
         */
        int y;

        /** @funcs: CRTC control functions */
        const struct drm_crtc_funcs *funcs;

        /**
         * @gamma_size: Size of legacy gamma ramp reported to userspace. Set up
         * by calling drm_mode_crtc_set_gamma_size().
         */
        uint32_t gamma_size;

        /**
         * @gamma_store: Gamma ramp values used by the legacy SETGAMMA and
         * GETGAMMA IOCTls. Set up by calling drm_mode_crtc_set_gamma_size().
         */
        uint16_t *gamma_store;

        /** @helper_private: mid-layer private data */
        const struct drm_crtc_helper_funcs *helper_private;

        /** @properties: property tracking for this CRTC */
        struct drm_object_properties properties;

        /**
         * @state:
         *
         * Current atomic state for this CRTC.
         *
         * This is protected by @mutex. Note that nonblocking atomic commits
         * access the current CRTC state without taking locks. Either by going
         * through the &struct drm_atomic_state pointers, see
         * for_each_oldnew_crtc_in_state(), for_each_old_crtc_in_state() and
         * for_each_new_crtc_in_state(). Or through careful ordering of atomic
         * commit operations as implemented in the atomic helpers, see
         * &struct drm_crtc_commit.
         */
        struct drm_crtc_state *state;

        /**
         * @commit_list:
         *
         * List of &drm_crtc_commit structures tracking pending commits.
         * Protected by @commit_lock. This list holds its own full reference,
         * as does the ongoing commit.
         *
         * "Note that the commit for a state change is also tracked in
         * &drm_crtc_state.commit. For accessing the immediately preceding
         * commit in an atomic update it is recommended to just use that
         * pointer in the old CRTC state, since accessing that doesn't need
         * any locking or list-walking. @commit_list should only be used to
         * stall for framebuffer cleanup that's signalled through
         * &drm_crtc_commit.cleanup_done."
         */
        struct list_head commit_list;

        /**
         * @commit_lock:
         *
         * Spinlock to protect @commit_list.
         */
        spinlock_t commit_lock;

#ifdef CONFIG_DEBUG_FS
        /**
         * @debugfs_entry:
         *
         * Debugfs directory for this CRTC.
         */
        struct dentry *debugfs_entry;
#endif

        /**
         * @crc:
         *
         * Configuration settings of CRC capture.
         */
        struct drm_crtc_crc crc;

        /**
         * @fence_context:
         *
         * timeline context used for fence operations.
         */
        unsigned int fence_context;

        /**
         * @fence_lock:
         *
         * spinlock to protect the fences in the fence_context.
         */
        spinlock_t fence_lock;
        /**
         * @fence_seqno:
         *
         * Seqno variable used as monotonic counter for the fences
         * created on the CRTC's timeline.
         */
        unsigned long fence_seqno;

        /**
         * @timeline_name:
         *
         * The name of the CRTC's fence timeline.
         */
        char timeline_name[32];
};

/**
 * struct drm_mode_set - new values for a CRTC config change
 * @fb: framebuffer to use for new config
 * @crtc: CRTC whose configuration we're about to change
 * @mode: mode timings to use
 * @x: position of this CRTC relative to @fb
 * @y: position of this CRTC relative to @fb
 * @connectors: array of connectors to drive with this CRTC if possible
 * @num_connectors: size of @connectors array
 *
 * This represents a modeset configuration for the legacy SETCRTC ioctl and is
 * also used internally. Atomic drivers instead use &drm_atomic_state.
 */
struct drm_mode_set {
        struct drm_framebuffer *fb;
        struct drm_crtc *crtc;
        struct drm_display_mode *mode;

        uint32_t x;
        uint32_t y;

        struct drm_connector **connectors;
        size_t num_connectors;
};

#define obj_to_crtc(x) container_of(x, struct drm_crtc, base)

__printf(6, 7)
int drm_crtc_init_with_planes(struct drm_device *dev,
                              struct drm_crtc *crtc,
                              struct drm_plane *primary,
                              struct drm_plane *cursor,
                              const struct drm_crtc_funcs *funcs,
                              const char *name, ...);
void drm_crtc_cleanup(struct drm_crtc *crtc);

/**
 * drm_crtc_index - find the index of a registered CRTC
 * @crtc: CRTC to find index for
 *
 * Given a registered CRTC, return the index of that CRTC within a DRM
 * device's list of CRTCs.
 */
static inline unsigned int drm_crtc_index(const struct drm_crtc *crtc)
{
        return crtc->index;
}

/**
 * drm_crtc_mask - find the mask of a registered CRTC
 * @crtc: CRTC to find mask for
 *
 * Given a registered CRTC, return the mask bit of that CRTC for the
 * &drm_encoder.possible_crtcs and &drm_plane.possible_crtcs fields.
 */
static inline uint32_t drm_crtc_mask(const struct drm_crtc *crtc)
{
        return 1 << drm_crtc_index(crtc);
}

int drm_crtc_force_disable(struct drm_crtc *crtc);
int drm_crtc_force_disable_all(struct drm_device *dev);

int drm_mode_set_config_internal(struct drm_mode_set *set);
struct drm_crtc *drm_crtc_from_index(struct drm_device *dev, int idx);

/**
 * drm_crtc_find - look up a CRTC object from its ID
 * @dev: DRM device
 * @file_priv: drm file to check for lease against.
 * @id: &drm_mode_object ID
 *
 * This can be used to look up a CRTC from its userspace ID. Only used by
 * drivers for legacy IOCTLs and interface, nowadays extensions to the KMS
 * userspace interface should be done using &drm_property.
 */
static inline struct drm_crtc *drm_crtc_find(struct drm_device *dev,
                struct drm_file *file_priv,
                uint32_t id)
{
        struct drm_mode_object *mo;
        mo = drm_mode_object_find(dev, file_priv, id, DRM_MODE_OBJECT_CRTC);
        return mo ? obj_to_crtc(mo) : NULL;
}

/**
 * drm_for_each_crtc - iterate over all CRTCs
 * @crtc: a &struct drm_crtc as the loop cursor
 * @dev: the &struct drm_device
 *
 * Iterate over all CRTCs of @dev.
 */
#define drm_for_each_crtc(crtc, dev) \
        list_for_each_entry(crtc, &(dev)->mode_config.crtc_list, head)

#endif /* __DRM_CRTC_H__ */