[karo-tx-linux.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
 * @crtc: backpointer to the CRTC
 * @enable: whether the CRTC should be enabled, gates all other state
 * @active: whether the CRTC is actively displaying (used for DPMS)
 * @planes_changed: planes on this crtc are updated
 * @mode_changed: @mode or @enable has been changed
 * @active_changed: @active has been toggled.
 * @connectors_changed: connectors to this crtc have been updated
 * @zpos_changed: zpos values of planes on this crtc have been updated
 * @color_mgmt_changed: color management properties have changed (degamma or
 *      gamma LUT or CSC matrix)
 * @plane_mask: bitmask of (1 << drm_plane_index(plane)) of attached planes
 * @connector_mask: bitmask of (1 << drm_connector_index(connector)) of attached connectors
 * @encoder_mask: bitmask of (1 << drm_encoder_index(encoder)) of attached encoders
 * @adjusted_mode: for use by helpers and drivers to compute adjusted mode timings
 * @mode: current mode timings
 * @mode_blob: &drm_property_blob for @mode
 * @degamma_lut: Lookup table for converting framebuffer pixel data
 *      before apply the conversion matrix
 * @ctm: Transformation matrix
 * @gamma_lut: Lookup table for converting pixel data after the
 *      conversion matrix
 * @state: backpointer to global drm_atomic_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()
 */
struct drm_crtc_state {
        struct drm_crtc *crtc;

        bool enable;
        bool active;

        /* computed state bits used by helpers and drivers */
        bool planes_changed : 1;
        bool mode_changed : 1;
        bool active_changed : 1;
        bool connectors_changed : 1;
        bool zpos_changed : 1;
        bool color_mgmt_changed : 1;

        /* attached planes bitmask:
         * WARNING: transitional helpers do not maintain plane_mask so
         * drivers not converted over to atomic helpers should not rely
         * on plane_mask being accurate!
         */
        u32 plane_mask;

        u32 connector_mask;
        u32 encoder_mask;

        /* adjusted_mode: for use by helpers and drivers */
        struct drm_display_mode adjusted_mode;

        struct drm_display_mode mode;

        /* blob property to expose current mode to atomic userspace */
        struct drm_property_blob *mode_blob;

        /* blob property to expose color management to userspace */
        struct drm_property_blob *degamma_lut;
        struct drm_property_blob *ctm;
        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.
         *
         *  - 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;

        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.
         *
         * NOTE:
         *
         * Drivers that support gamma tables and also fbdev emulation through
         * the provided helper library need to take care to fill out the gamma
         * hooks for both. Currently there's a bit an unfortunate duplication
         * going on, which should eventually be unified to just one set of
         * hooks.
         */
        int (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
                         uint32_t size);

        /**
         * @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.
         *
         * Drivers implementing atomic modeset should use
         * drm_atomic_helper_crtc_set_property() to implement this hook.
         *
         * This callback is optional if the driver does not support any legacy
         * driver-private properties.
         *
         * 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.
         *
         * 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
         */
        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,
                              size_t *values_cnt);

        /**
         * @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.
         *
         * 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
 * @dev: parent DRM device
 * @port: OF node used by drm_of_find_possible_crtcs()
 * @head: list management
 * @name: human readable name, can be overwritten by the driver
 * @mutex: per-CRTC locking
 * @base: base KMS object for ID tracking etc.
 * @primary: primary plane for this CRTC
 * @cursor: cursor plane for this CRTC
 * @cursor_x: current x position of the cursor, used for universal cursor planes
 * @cursor_y: current y position of the cursor, used for universal cursor planes
 * @enabled: is this CRTC enabled?
 * @mode: current mode timings
 * @hwmode: mode timings as programmed to hw regs
 * @x: x position on screen
 * @y: y position on screen
 * @funcs: CRTC control functions
 * @gamma_size: size of gamma ramp
 * @gamma_store: gamma ramp values
 * @helper_private: mid-layer private data
 * @properties: property tracking for this CRTC
 *
 * Each CRTC may have one or more connectors associated with it.  This structure
 * allows the CRTC to be controlled.
 */
struct drm_crtc {
        struct drm_device *dev;
        struct device_node *port;
        struct list_head head;

        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;

        struct drm_mode_object base;

        /* primary and cursor planes for CRTC */
        struct drm_plane *primary;
        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;

        /* position of cursor plane on crtc */
        int cursor_x;
        int cursor_y;

        bool enabled;

        /* Requested mode from modesetting. */
        struct drm_display_mode mode;

        /* Programmed mode in hw, after adjustments for encoders,
         * crtc, panel scaling etc. Needed for timestamping etc.
         */
        struct drm_display_mode hwmode;

        int x, y;
        const struct drm_crtc_funcs *funcs;

        /* Legacy FB CRTC gamma size for reporting to userspace */
        uint32_t gamma_size;
        uint16_t *gamma_store;

        /* if you are using the helper */
        const struct drm_crtc_helper_funcs *helper_private;

        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_crtc_in_state(), 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 doesn't hold its own full
         * reference, but burrows it from the ongoing commit. Commit entries
         * must be removed from this list once the commit is fully completed,
         * but before it's correspoding &drm_atomic_state gets destroyed.
         */
        struct list_head commit_list;

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

        /**
         * @acquire_ctx:
         *
         * Per-CRTC implicit acquire context used by atomic drivers for legacy
         * IOCTLs, so that atomic drivers can get at the locking acquire
         * context.
         */
        struct drm_modeset_acquire_ctx *acquire_ctx;

#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 an
 * encoder's possible_crtcs field.
 */
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
 * @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,
        uint32_t id)
{
        struct drm_mode_object *mo;
        mo = drm_mode_object_find(dev, 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__ */