[mirror_ubuntu-bionic-kernel.git] / drivers / gpu / drm / drm_connector.c

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

#include <drm/drmP.h>
#include <drm/drm_connector.h>
#include <drm/drm_edid.h>
#include <drm/drm_encoder.h>

#include "drm_crtc_internal.h"
#include "drm_internal.h"

/**
 * DOC: overview
 *
 * In DRM connectors are the general abstraction for display sinks, and include
 * als fixed panels or anything else that can display pixels in some form. As
 * opposed to all other KMS objects representing hardware (like CRTC, encoder or
 * plane abstractions) connectors can be hotplugged and unplugged at runtime.
 * Hence they are reference-counted using drm_connector_get() and
 * drm_connector_put().
 *
 * KMS driver must create, initialize, register and attach at a &struct
 * drm_connector for each such sink. The instance is created as other KMS
 * objects and initialized by setting the following fields. The connector is
 * initialized with a call to drm_connector_init() with a pointer to the
 * &struct drm_connector_funcs and a connector type, and then exposed to
 * userspace with a call to drm_connector_register().
 *
 * Connectors must be attached to an encoder to be used. For devices that map
 * connectors to encoders 1:1, the connector should be attached at
 * initialization time with a call to drm_mode_connector_attach_encoder(). The
 * driver must also set the &drm_connector.encoder field to point to the
 * attached encoder.
 *
 * For connectors which are not fixed (like built-in panels) the driver needs to
 * support hotplug notifications. The simplest way to do that is by using the
 * probe helpers, see drm_kms_helper_poll_init() for connectors which don't have
 * hardware support for hotplug interrupts. Connectors with hardware hotplug
 * support can instead use e.g. drm_helper_hpd_irq_event().
 */

struct drm_conn_prop_enum_list {
        int type;
        const char *name;
        struct ida ida;
};

/*
 * Connector and encoder types.
 */
static struct drm_conn_prop_enum_list drm_connector_enum_list[] = {
        { DRM_MODE_CONNECTOR_Unknown, "Unknown" },
        { DRM_MODE_CONNECTOR_VGA, "VGA" },
        { DRM_MODE_CONNECTOR_DVII, "DVI-I" },
        { DRM_MODE_CONNECTOR_DVID, "DVI-D" },
        { DRM_MODE_CONNECTOR_DVIA, "DVI-A" },
        { DRM_MODE_CONNECTOR_Composite, "Composite" },
        { DRM_MODE_CONNECTOR_SVIDEO, "SVIDEO" },
        { DRM_MODE_CONNECTOR_LVDS, "LVDS" },
        { DRM_MODE_CONNECTOR_Component, "Component" },
        { DRM_MODE_CONNECTOR_9PinDIN, "DIN" },
        { DRM_MODE_CONNECTOR_DisplayPort, "DP" },
        { DRM_MODE_CONNECTOR_HDMIA, "HDMI-A" },
        { DRM_MODE_CONNECTOR_HDMIB, "HDMI-B" },
        { DRM_MODE_CONNECTOR_TV, "TV" },
        { DRM_MODE_CONNECTOR_eDP, "eDP" },
        { DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" },
        { DRM_MODE_CONNECTOR_DSI, "DSI" },
        { DRM_MODE_CONNECTOR_DPI, "DPI" },
};

void drm_connector_ida_init(void)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(drm_connector_enum_list); i++)
                ida_init(&drm_connector_enum_list[i].ida);
}

void drm_connector_ida_destroy(void)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(drm_connector_enum_list); i++)
                ida_destroy(&drm_connector_enum_list[i].ida);
}

/**
 * drm_connector_get_cmdline_mode - reads the user's cmdline mode
 * @connector: connector to quwery
 *
 * The kernel supports per-connector configuration of its consoles through
 * use of the video= parameter. This function parses that option and
 * extracts the user's specified mode (or enable/disable status) for a
 * particular connector. This is typically only used during the early fbdev
 * setup.
 */
static void drm_connector_get_cmdline_mode(struct drm_connector *connector)
{
        struct drm_cmdline_mode *mode = &connector->cmdline_mode;
        char *option = NULL;

        if (fb_get_options(connector->name, &option))
                return;

        if (!drm_mode_parse_command_line_for_connector(option,
                                                       connector,
                                                       mode))
                return;

        if (mode->force) {
                DRM_INFO("forcing %s connector %s\n", connector->name,
                         drm_get_connector_force_name(mode->force));
                connector->force = mode->force;
        }

        DRM_DEBUG_KMS("cmdline mode for connector %s %dx%d@%dHz%s%s%s\n",
                      connector->name,
                      mode->xres, mode->yres,
                      mode->refresh_specified ? mode->refresh : 60,
                      mode->rb ? " reduced blanking" : "",
                      mode->margins ? " with margins" : "",
                      mode->interlace ?  " interlaced" : "");
}

static void drm_connector_free(struct kref *kref)
{
        struct drm_connector *connector =
                container_of(kref, struct drm_connector, base.refcount);
        struct drm_device *dev = connector->dev;

        drm_mode_object_unregister(dev, &connector->base);
        connector->funcs->destroy(connector);
}

/**
 * drm_connector_init - Init a preallocated connector
 * @dev: DRM device
 * @connector: the connector to init
 * @funcs: callbacks for this connector
 * @connector_type: user visible type of the connector
 *
 * Initialises a preallocated connector. Connectors should be
 * subclassed as part of driver connector objects.
 *
 * Returns:
 * Zero on success, error code on failure.
 */
int drm_connector_init(struct drm_device *dev,
                       struct drm_connector *connector,
                       const struct drm_connector_funcs *funcs,
                       int connector_type)
{
        struct drm_mode_config *config = &dev->mode_config;
        int ret;
        struct ida *connector_ida =
                &drm_connector_enum_list[connector_type].ida;

        ret = __drm_mode_object_add(dev, &connector->base,
                                    DRM_MODE_OBJECT_CONNECTOR,
                                    false, drm_connector_free);
        if (ret)
                return ret;

        connector->base.properties = &connector->properties;
        connector->dev = dev;
        connector->funcs = funcs;

        ret = ida_simple_get(&config->connector_ida, 0, 0, GFP_KERNEL);
        if (ret < 0)
                goto out_put;
        connector->index = ret;
        ret = 0;

        connector->connector_type = connector_type;
        connector->connector_type_id =
                ida_simple_get(connector_ida, 1, 0, GFP_KERNEL);
        if (connector->connector_type_id < 0) {
                ret = connector->connector_type_id;
                goto out_put_id;
        }
        connector->name =
                kasprintf(GFP_KERNEL, "%s-%d",
                          drm_connector_enum_list[connector_type].name,
                          connector->connector_type_id);
        if (!connector->name) {
                ret = -ENOMEM;
                goto out_put_type_id;
        }

        INIT_LIST_HEAD(&connector->probed_modes);
        INIT_LIST_HEAD(&connector->modes);
        mutex_init(&connector->mutex);
        connector->edid_blob_ptr = NULL;
        connector->status = connector_status_unknown;

        drm_connector_get_cmdline_mode(connector);

        /* We should add connectors at the end to avoid upsetting the connector
         * index too much. */
        spin_lock_irq(&config->connector_list_lock);
        list_add_tail(&connector->head, &config->connector_list);
        config->num_connector++;
        spin_unlock_irq(&config->connector_list_lock);

        if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL)
                drm_object_attach_property(&connector->base,
                                              config->edid_property,
                                              0);

        drm_object_attach_property(&connector->base,
                                      config->dpms_property, 0);

        drm_object_attach_property(&connector->base,
                                   config->link_status_property,
                                   0);

        if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
                drm_object_attach_property(&connector->base, config->prop_crtc_id, 0);
        }

        connector->debugfs_entry = NULL;
out_put_type_id:
        if (ret)
                ida_simple_remove(connector_ida, connector->connector_type_id);
out_put_id:
        if (ret)
                ida_simple_remove(&config->connector_ida, connector->index);
out_put:
        if (ret)
                drm_mode_object_unregister(dev, &connector->base);

        return ret;
}
EXPORT_SYMBOL(drm_connector_init);

/**
 * drm_mode_connector_attach_encoder - attach a connector to an encoder
 * @connector: connector to attach
 * @encoder: encoder to attach @connector to
 *
 * This function links up a connector to an encoder. Note that the routing
 * restrictions between encoders and crtcs are exposed to userspace through the
 * possible_clones and possible_crtcs bitmasks.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_connector_attach_encoder(struct drm_connector *connector,
                                      struct drm_encoder *encoder)
{
        int i;

        /*
         * In the past, drivers have attempted to model the static association
         * of connector to encoder in simple connector/encoder devices using a
         * direct assignment of connector->encoder = encoder. This connection
         * is a logical one and the responsibility of the core, so drivers are
         * expected not to mess with this.
         *
         * Note that the error return should've been enough here, but a large
         * majority of drivers ignores the return value, so add in a big WARN
         * to get people's attention.
         */
        if (WARN_ON(connector->encoder))
                return -EINVAL;

        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
                if (connector->encoder_ids[i] == 0) {
                        connector->encoder_ids[i] = encoder->base.id;
                        return 0;
                }
        }
        return -ENOMEM;
}
EXPORT_SYMBOL(drm_mode_connector_attach_encoder);

static void drm_mode_remove(struct drm_connector *connector,
                            struct drm_display_mode *mode)
{
        list_del(&mode->head);
        drm_mode_destroy(connector->dev, mode);
}

/**
 * drm_connector_cleanup - cleans up an initialised connector
 * @connector: connector to cleanup
 *
 * Cleans up the connector but doesn't free the object.
 */
void drm_connector_cleanup(struct drm_connector *connector)
{
        struct drm_device *dev = connector->dev;
        struct drm_display_mode *mode, *t;

        /* The connector should have been removed from userspace long before
         * it is finally destroyed.
         */
        if (WARN_ON(connector->registered))
                drm_connector_unregister(connector);

        if (connector->tile_group) {
                drm_mode_put_tile_group(dev, connector->tile_group);
                connector->tile_group = NULL;
        }

        list_for_each_entry_safe(mode, t, &connector->probed_modes, head)
                drm_mode_remove(connector, mode);

        list_for_each_entry_safe(mode, t, &connector->modes, head)
                drm_mode_remove(connector, mode);

        ida_simple_remove(&drm_connector_enum_list[connector->connector_type].ida,
                          connector->connector_type_id);

        ida_simple_remove(&dev->mode_config.connector_ida,
                          connector->index);

        kfree(connector->display_info.bus_formats);
        drm_mode_object_unregister(dev, &connector->base);
        kfree(connector->name);
        connector->name = NULL;
        spin_lock_irq(&dev->mode_config.connector_list_lock);
        list_del(&connector->head);
        dev->mode_config.num_connector--;
        spin_unlock_irq(&dev->mode_config.connector_list_lock);

        WARN_ON(connector->state && !connector->funcs->atomic_destroy_state);
        if (connector->state && connector->funcs->atomic_destroy_state)
                connector->funcs->atomic_destroy_state(connector,
                                                       connector->state);

        mutex_destroy(&connector->mutex);

        memset(connector, 0, sizeof(*connector));
}
EXPORT_SYMBOL(drm_connector_cleanup);

/**
 * drm_connector_register - register a connector
 * @connector: the connector to register
 *
 * Register userspace interfaces for a connector
 *
 * Returns:
 * Zero on success, error code on failure.
 */
int drm_connector_register(struct drm_connector *connector)
{
        int ret = 0;

        if (!connector->dev->registered)
                return 0;

        mutex_lock(&connector->mutex);
        if (connector->registered)
                goto unlock;

        ret = drm_sysfs_connector_add(connector);
        if (ret)
                goto unlock;

        ret = drm_debugfs_connector_add(connector);
        if (ret) {
                goto err_sysfs;
        }

        if (connector->funcs->late_register) {
                ret = connector->funcs->late_register(connector);
                if (ret)
                        goto err_debugfs;
        }

        drm_mode_object_register(connector->dev, &connector->base);

        connector->registered = true;
        goto unlock;

err_debugfs:
        drm_debugfs_connector_remove(connector);
err_sysfs:
        drm_sysfs_connector_remove(connector);
unlock:
        mutex_unlock(&connector->mutex);
        return ret;
}
EXPORT_SYMBOL(drm_connector_register);

/**
 * drm_connector_unregister - unregister a connector
 * @connector: the connector to unregister
 *
 * Unregister userspace interfaces for a connector
 */
void drm_connector_unregister(struct drm_connector *connector)
{
        mutex_lock(&connector->mutex);
        if (!connector->registered) {
                mutex_unlock(&connector->mutex);
                return;
        }

        if (connector->funcs->early_unregister)
                connector->funcs->early_unregister(connector);

        drm_sysfs_connector_remove(connector);
        drm_debugfs_connector_remove(connector);

        connector->registered = false;
        mutex_unlock(&connector->mutex);
}
EXPORT_SYMBOL(drm_connector_unregister);

void drm_connector_unregister_all(struct drm_device *dev)
{
        struct drm_connector *connector;
        struct drm_connector_list_iter conn_iter;

        drm_connector_list_iter_begin(dev, &conn_iter);
        drm_for_each_connector_iter(connector, &conn_iter)
                drm_connector_unregister(connector);
        drm_connector_list_iter_end(&conn_iter);
}

int drm_connector_register_all(struct drm_device *dev)
{
        struct drm_connector *connector;
        struct drm_connector_list_iter conn_iter;
        int ret = 0;

        drm_connector_list_iter_begin(dev, &conn_iter);
        drm_for_each_connector_iter(connector, &conn_iter) {
                ret = drm_connector_register(connector);
                if (ret)
                        break;
        }
        drm_connector_list_iter_end(&conn_iter);

        if (ret)
                drm_connector_unregister_all(dev);
        return ret;
}

/**
 * drm_get_connector_status_name - return a string for connector status
 * @status: connector status to compute name of
 *
 * In contrast to the other drm_get_*_name functions this one here returns a
 * const pointer and hence is threadsafe.
 */
const char *drm_get_connector_status_name(enum drm_connector_status status)
{
        if (status == connector_status_connected)
                return "connected";
        else if (status == connector_status_disconnected)
                return "disconnected";
        else
                return "unknown";
}
EXPORT_SYMBOL(drm_get_connector_status_name);

/**
 * drm_get_connector_force_name - return a string for connector force
 * @force: connector force to get name of
 *
 * Returns: const pointer to name.
 */
const char *drm_get_connector_force_name(enum drm_connector_force force)
{
        switch (force) {
        case DRM_FORCE_UNSPECIFIED:
                return "unspecified";
        case DRM_FORCE_OFF:
                return "off";
        case DRM_FORCE_ON:
                return "on";
        case DRM_FORCE_ON_DIGITAL:
                return "digital";
        default:
                return "unknown";
        }
}

#ifdef CONFIG_LOCKDEP
static struct lockdep_map connector_list_iter_dep_map = {
        .name = "drm_connector_list_iter"
};
#endif

/**
 * drm_connector_list_iter_begin - initialize a connector_list iterator
 * @dev: DRM device
 * @iter: connector_list iterator
 *
 * Sets @iter up to walk the &drm_mode_config.connector_list of @dev. @iter
 * must always be cleaned up again by calling drm_connector_list_iter_end().
 * Iteration itself happens using drm_connector_list_iter_next() or
 * drm_for_each_connector_iter().
 */
void drm_connector_list_iter_begin(struct drm_device *dev,
                                   struct drm_connector_list_iter *iter)
{
        iter->dev = dev;
        iter->conn = NULL;
        lock_acquire_shared_recursive(&connector_list_iter_dep_map, 0, 1, NULL, _RET_IP_);
}
EXPORT_SYMBOL(drm_connector_list_iter_begin);

/**
 * drm_connector_list_iter_next - return next connector
 * @iter: connectr_list iterator
 *
 * Returns the next connector for @iter, or NULL when the list walk has
 * completed.
 */
struct drm_connector *
drm_connector_list_iter_next(struct drm_connector_list_iter *iter)
{
        struct drm_connector *old_conn = iter->conn;
        struct drm_mode_config *config = &iter->dev->mode_config;
        struct list_head *lhead;
        unsigned long flags;

        spin_lock_irqsave(&config->connector_list_lock, flags);
        lhead = old_conn ? &old_conn->head : &config->connector_list;

        do {
                if (lhead->next == &config->connector_list) {
                        iter->conn = NULL;
                        break;
                }

                lhead = lhead->next;
                iter->conn = list_entry(lhead, struct drm_connector, head);

                /* loop until it's not a zombie connector */
        } while (!kref_get_unless_zero(&iter->conn->base.refcount));
        spin_unlock_irqrestore(&config->connector_list_lock, flags);

        if (old_conn)
                drm_connector_put(old_conn);

        return iter->conn;
}
EXPORT_SYMBOL(drm_connector_list_iter_next);

/**
 * drm_connector_list_iter_end - tear down a connector_list iterator
 * @iter: connector_list iterator
 *
 * Tears down @iter and releases any resources (like &drm_connector references)
 * acquired while walking the list. This must always be called, both when the
 * iteration completes fully or when it was aborted without walking the entire
 * list.
 */
void drm_connector_list_iter_end(struct drm_connector_list_iter *iter)
{
        iter->dev = NULL;
        if (iter->conn)
                drm_connector_put(iter->conn);
        lock_release(&connector_list_iter_dep_map, 0, _RET_IP_);
}
EXPORT_SYMBOL(drm_connector_list_iter_end);

static const struct drm_prop_enum_list drm_subpixel_enum_list[] = {
        { SubPixelUnknown, "Unknown" },
        { SubPixelHorizontalRGB, "Horizontal RGB" },
        { SubPixelHorizontalBGR, "Horizontal BGR" },
        { SubPixelVerticalRGB, "Vertical RGB" },
        { SubPixelVerticalBGR, "Vertical BGR" },
        { SubPixelNone, "None" },
};

/**
 * drm_get_subpixel_order_name - return a string for a given subpixel enum
 * @order: enum of subpixel_order
 *
 * Note you could abuse this and return something out of bounds, but that
 * would be a caller error.  No unscrubbed user data should make it here.
 */
const char *drm_get_subpixel_order_name(enum subpixel_order order)
{
        return drm_subpixel_enum_list[order].name;
}
EXPORT_SYMBOL(drm_get_subpixel_order_name);

static const struct drm_prop_enum_list drm_dpms_enum_list[] = {
        { DRM_MODE_DPMS_ON, "On" },
        { DRM_MODE_DPMS_STANDBY, "Standby" },
        { DRM_MODE_DPMS_SUSPEND, "Suspend" },
        { DRM_MODE_DPMS_OFF, "Off" }
};
DRM_ENUM_NAME_FN(drm_get_dpms_name, drm_dpms_enum_list)

static const struct drm_prop_enum_list drm_link_status_enum_list[] = {
        { DRM_MODE_LINK_STATUS_GOOD, "Good" },
        { DRM_MODE_LINK_STATUS_BAD, "Bad" },
};
DRM_ENUM_NAME_FN(drm_get_link_status_name, drm_link_status_enum_list)

/**
 * drm_display_info_set_bus_formats - set the supported bus formats
 * @info: display info to store bus formats in
 * @formats: array containing the supported bus formats
 * @num_formats: the number of entries in the fmts array
 *
 * Store the supported bus formats in display info structure.
 * See MEDIA_BUS_FMT_* definitions in include/uapi/linux/media-bus-format.h for
 * a full list of available formats.
 */
int drm_display_info_set_bus_formats(struct drm_display_info *info,
                                     const u32 *formats,
                                     unsigned int num_formats)
{
        u32 *fmts = NULL;

        if (!formats && num_formats)
                return -EINVAL;

        if (formats && num_formats) {
                fmts = kmemdup(formats, sizeof(*formats) * num_formats,
                               GFP_KERNEL);
                if (!fmts)
                        return -ENOMEM;
        }

        kfree(info->bus_formats);
        info->bus_formats = fmts;
        info->num_bus_formats = num_formats;

        return 0;
}
EXPORT_SYMBOL(drm_display_info_set_bus_formats);

/* Optional connector properties. */
static const struct drm_prop_enum_list drm_scaling_mode_enum_list[] = {
        { DRM_MODE_SCALE_NONE, "None" },
        { DRM_MODE_SCALE_FULLSCREEN, "Full" },
        { DRM_MODE_SCALE_CENTER, "Center" },
        { DRM_MODE_SCALE_ASPECT, "Full aspect" },
};

static const struct drm_prop_enum_list drm_aspect_ratio_enum_list[] = {
        { DRM_MODE_PICTURE_ASPECT_NONE, "Automatic" },
        { DRM_MODE_PICTURE_ASPECT_4_3, "4:3" },
        { DRM_MODE_PICTURE_ASPECT_16_9, "16:9" },
};

static const struct drm_prop_enum_list drm_dvi_i_select_enum_list[] = {
        { DRM_MODE_SUBCONNECTOR_Automatic, "Automatic" }, /* DVI-I and TV-out */
        { DRM_MODE_SUBCONNECTOR_DVID,      "DVI-D"     }, /* DVI-I  */
        { DRM_MODE_SUBCONNECTOR_DVIA,      "DVI-A"     }, /* DVI-I  */
};
DRM_ENUM_NAME_FN(drm_get_dvi_i_select_name, drm_dvi_i_select_enum_list)

static const struct drm_prop_enum_list drm_dvi_i_subconnector_enum_list[] = {
        { DRM_MODE_SUBCONNECTOR_Unknown,   "Unknown"   }, /* DVI-I and TV-out */
        { DRM_MODE_SUBCONNECTOR_DVID,      "DVI-D"     }, /* DVI-I  */
        { DRM_MODE_SUBCONNECTOR_DVIA,      "DVI-A"     }, /* DVI-I  */
};
DRM_ENUM_NAME_FN(drm_get_dvi_i_subconnector_name,
                 drm_dvi_i_subconnector_enum_list)

static const struct drm_prop_enum_list drm_tv_select_enum_list[] = {
        { DRM_MODE_SUBCONNECTOR_Automatic, "Automatic" }, /* DVI-I and TV-out */
        { DRM_MODE_SUBCONNECTOR_Composite, "Composite" }, /* TV-out */
        { DRM_MODE_SUBCONNECTOR_SVIDEO,    "SVIDEO"    }, /* TV-out */
        { DRM_MODE_SUBCONNECTOR_Component, "Component" }, /* TV-out */
        { DRM_MODE_SUBCONNECTOR_SCART,     "SCART"     }, /* TV-out */
};
DRM_ENUM_NAME_FN(drm_get_tv_select_name, drm_tv_select_enum_list)

static const struct drm_prop_enum_list drm_tv_subconnector_enum_list[] = {
        { DRM_MODE_SUBCONNECTOR_Unknown,   "Unknown"   }, /* DVI-I and TV-out */
        { DRM_MODE_SUBCONNECTOR_Composite, "Composite" }, /* TV-out */
        { DRM_MODE_SUBCONNECTOR_SVIDEO,    "SVIDEO"    }, /* TV-out */
        { DRM_MODE_SUBCONNECTOR_Component, "Component" }, /* TV-out */
        { DRM_MODE_SUBCONNECTOR_SCART,     "SCART"     }, /* TV-out */
};
DRM_ENUM_NAME_FN(drm_get_tv_subconnector_name,
                 drm_tv_subconnector_enum_list)

/**
 * DOC: standard connector properties
 *
 * DRM connectors have a few standardized properties:
 *
 * EDID:
 *      Blob property which contains the current EDID read from the sink. This
 *      is useful to parse sink identification information like vendor, model
 *      and serial. Drivers should update this property by calling
 *      drm_mode_connector_update_edid_property(), usually after having parsed
 *      the EDID using drm_add_edid_modes(). Userspace cannot change this
 *      property.
 * DPMS:
 *      Legacy property for setting the power state of the connector. For atomic
 *      drivers this is only provided for backwards compatibility with existing
 *      drivers, it remaps to controlling the "ACTIVE" property on the CRTC the
 *      connector is linked to. Drivers should never set this property directly,
 *      it is handled by the DRM core by calling the &drm_connector_funcs.dpms
 *      callback. Atomic drivers should implement this hook using
 *      drm_atomic_helper_connector_dpms(). This is the only property standard
 *      connector property that userspace can change.
 * PATH:
 *      Connector path property to identify how this sink is physically
 *      connected. Used by DP MST. This should be set by calling
 *      drm_mode_connector_set_path_property(), in the case of DP MST with the
 *      path property the MST manager created. Userspace cannot change this
 *      property.
 * TILE:
 *      Connector tile group property to indicate how a set of DRM connector
 *      compose together into one logical screen. This is used by both high-res
 *      external screens (often only using a single cable, but exposing multiple
 *      DP MST sinks), or high-res integrated panels (like dual-link DSI) which
 *      are not gen-locked. Note that for tiled panels which are genlocked, like
 *      dual-link LVDS or dual-link DSI, the driver should try to not expose the
 *      tiling and virtualize both &drm_crtc and &drm_plane if needed. Drivers
 *      should update this value using drm_mode_connector_set_tile_property().
 *      Userspace cannot change this property.
 * link-status:
 *      Connector link-status property to indicate the status of link. The default
 *      value of link-status is "GOOD". If something fails during or after modeset,
 *      the kernel driver may set this to "BAD" and issue a hotplug uevent. Drivers
 *      should update this value using drm_mode_connector_set_link_status_property().
 *
 * Connectors also have one standardized atomic property:
 *
 * CRTC_ID:
 *      Mode object ID of the &drm_crtc this connector should be connected to.
 */

int drm_connector_create_standard_properties(struct drm_device *dev)
{
        struct drm_property *prop;

        prop = drm_property_create(dev, DRM_MODE_PROP_BLOB |
                                   DRM_MODE_PROP_IMMUTABLE,
                                   "EDID", 0);
        if (!prop)
                return -ENOMEM;
        dev->mode_config.edid_property = prop;

        prop = drm_property_create_enum(dev, 0,
                                   "DPMS", drm_dpms_enum_list,
                                   ARRAY_SIZE(drm_dpms_enum_list));
        if (!prop)
                return -ENOMEM;
        dev->mode_config.dpms_property = prop;

        prop = drm_property_create(dev,
                                   DRM_MODE_PROP_BLOB |
                                   DRM_MODE_PROP_IMMUTABLE,
                                   "PATH", 0);
        if (!prop)
                return -ENOMEM;
        dev->mode_config.path_property = prop;

        prop = drm_property_create(dev,
                                   DRM_MODE_PROP_BLOB |
                                   DRM_MODE_PROP_IMMUTABLE,
                                   "TILE", 0);
        if (!prop)
                return -ENOMEM;
        dev->mode_config.tile_property = prop;

        prop = drm_property_create_enum(dev, 0, "link-status",
                                        drm_link_status_enum_list,
                                        ARRAY_SIZE(drm_link_status_enum_list));
        if (!prop)
                return -ENOMEM;
        dev->mode_config.link_status_property = prop;

        return 0;
}

/**
 * drm_mode_create_dvi_i_properties - create DVI-I specific connector properties
 * @dev: DRM device
 *
 * Called by a driver the first time a DVI-I connector is made.
 */
int drm_mode_create_dvi_i_properties(struct drm_device *dev)
{
        struct drm_property *dvi_i_selector;
        struct drm_property *dvi_i_subconnector;

        if (dev->mode_config.dvi_i_select_subconnector_property)
                return 0;

        dvi_i_selector =
                drm_property_create_enum(dev, 0,
                                    "select subconnector",
                                    drm_dvi_i_select_enum_list,
                                    ARRAY_SIZE(drm_dvi_i_select_enum_list));
        dev->mode_config.dvi_i_select_subconnector_property = dvi_i_selector;

        dvi_i_subconnector = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE,
                                    "subconnector",
                                    drm_dvi_i_subconnector_enum_list,
                                    ARRAY_SIZE(drm_dvi_i_subconnector_enum_list));
        dev->mode_config.dvi_i_subconnector_property = dvi_i_subconnector;

        return 0;
}
EXPORT_SYMBOL(drm_mode_create_dvi_i_properties);

/**
 * drm_create_tv_properties - create TV specific connector properties
 * @dev: DRM device
 * @num_modes: number of different TV formats (modes) supported
 * @modes: array of pointers to strings containing name of each format
 *
 * Called by a driver's TV initialization routine, this function creates
 * the TV specific connector properties for a given device.  Caller is
 * responsible for allocating a list of format names and passing them to
 * this routine.
 */
int drm_mode_create_tv_properties(struct drm_device *dev,
                                  unsigned int num_modes,
                                  const char * const modes[])
{
        struct drm_property *tv_selector;
        struct drm_property *tv_subconnector;
        unsigned int i;

        if (dev->mode_config.tv_select_subconnector_property)
                return 0;

        /*
         * Basic connector properties
         */
        tv_selector = drm_property_create_enum(dev, 0,
                                          "select subconnector",
                                          drm_tv_select_enum_list,
                                          ARRAY_SIZE(drm_tv_select_enum_list));
        if (!tv_selector)
                goto nomem;

        dev->mode_config.tv_select_subconnector_property = tv_selector;

        tv_subconnector =
                drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE,
                                    "subconnector",
                                    drm_tv_subconnector_enum_list,
                                    ARRAY_SIZE(drm_tv_subconnector_enum_list));
        if (!tv_subconnector)
                goto nomem;
        dev->mode_config.tv_subconnector_property = tv_subconnector;

        /*
         * Other, TV specific properties: margins & TV modes.
         */
        dev->mode_config.tv_left_margin_property =
                drm_property_create_range(dev, 0, "left margin", 0, 100);
        if (!dev->mode_config.tv_left_margin_property)
                goto nomem;

        dev->mode_config.tv_right_margin_property =
                drm_property_create_range(dev, 0, "right margin", 0, 100);
        if (!dev->mode_config.tv_right_margin_property)
                goto nomem;

        dev->mode_config.tv_top_margin_property =
                drm_property_create_range(dev, 0, "top margin", 0, 100);
        if (!dev->mode_config.tv_top_margin_property)
                goto nomem;

        dev->mode_config.tv_bottom_margin_property =
                drm_property_create_range(dev, 0, "bottom margin", 0, 100);
        if (!dev->mode_config.tv_bottom_margin_property)
                goto nomem;

        dev->mode_config.tv_mode_property =
                drm_property_create(dev, DRM_MODE_PROP_ENUM,
                                    "mode", num_modes);
        if (!dev->mode_config.tv_mode_property)
                goto nomem;

        for (i = 0; i < num_modes; i++)
                drm_property_add_enum(dev->mode_config.tv_mode_property, i,
                                      i, modes[i]);

        dev->mode_config.tv_brightness_property =
                drm_property_create_range(dev, 0, "brightness", 0, 100);
        if (!dev->mode_config.tv_brightness_property)
                goto nomem;

        dev->mode_config.tv_contrast_property =
                drm_property_create_range(dev, 0, "contrast", 0, 100);
        if (!dev->mode_config.tv_contrast_property)
                goto nomem;

        dev->mode_config.tv_flicker_reduction_property =
                drm_property_create_range(dev, 0, "flicker reduction", 0, 100);
        if (!dev->mode_config.tv_flicker_reduction_property)
                goto nomem;

        dev->mode_config.tv_overscan_property =
                drm_property_create_range(dev, 0, "overscan", 0, 100);
        if (!dev->mode_config.tv_overscan_property)
                goto nomem;

        dev->mode_config.tv_saturation_property =
                drm_property_create_range(dev, 0, "saturation", 0, 100);
        if (!dev->mode_config.tv_saturation_property)
                goto nomem;

        dev->mode_config.tv_hue_property =
                drm_property_create_range(dev, 0, "hue", 0, 100);
        if (!dev->mode_config.tv_hue_property)
                goto nomem;

        return 0;
nomem:
        return -ENOMEM;
}
EXPORT_SYMBOL(drm_mode_create_tv_properties);

/**
 * drm_mode_create_scaling_mode_property - create scaling mode property
 * @dev: DRM device
 *
 * Called by a driver the first time it's needed, must be attached to desired
 * connectors.
 *
 * Atomic drivers should use drm_connector_attach_scaling_mode_property()
 * instead to correctly assign &drm_connector_state.picture_aspect_ratio
 * in the atomic state.
 */
int drm_mode_create_scaling_mode_property(struct drm_device *dev)
{
        struct drm_property *scaling_mode;

        if (dev->mode_config.scaling_mode_property)
                return 0;

        scaling_mode =
                drm_property_create_enum(dev, 0, "scaling mode",
                                drm_scaling_mode_enum_list,
                                    ARRAY_SIZE(drm_scaling_mode_enum_list));

        dev->mode_config.scaling_mode_property = scaling_mode;

        return 0;
}
EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);

/**
 * drm_connector_attach_scaling_mode_property - attach atomic scaling mode property
 * @connector: connector to attach scaling mode property on.
 * @scaling_mode_mask: or'ed mask of BIT(%DRM_MODE_SCALE_\*).
 *
 * This is used to add support for scaling mode to atomic drivers.
 * The scaling mode will be set to &drm_connector_state.picture_aspect_ratio
 * and can be used from &drm_connector_helper_funcs->atomic_check for validation.
 *
 * This is the atomic version of drm_mode_create_scaling_mode_property().
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_connector_attach_scaling_mode_property(struct drm_connector *connector,
                                               u32 scaling_mode_mask)
{
        struct drm_device *dev = connector->dev;
        struct drm_property *scaling_mode_property;
        int i, j = 0;
        const unsigned valid_scaling_mode_mask =
                (1U << ARRAY_SIZE(drm_scaling_mode_enum_list)) - 1;

        if (WARN_ON(hweight32(scaling_mode_mask) < 2 ||
                    scaling_mode_mask & ~valid_scaling_mode_mask))
                return -EINVAL;

        scaling_mode_property =
                drm_property_create(dev, DRM_MODE_PROP_ENUM, "scaling mode",
                                    hweight32(scaling_mode_mask));

        if (!scaling_mode_property)
                return -ENOMEM;

        for (i = 0; i < ARRAY_SIZE(drm_scaling_mode_enum_list); i++) {
                int ret;

                if (!(BIT(i) & scaling_mode_mask))
                        continue;

                ret = drm_property_add_enum(scaling_mode_property, j++,
                                            drm_scaling_mode_enum_list[i].type,
                                            drm_scaling_mode_enum_list[i].name);

                if (ret) {
                        drm_property_destroy(dev, scaling_mode_property);

                        return ret;
                }
        }

        drm_object_attach_property(&connector->base,
                                   scaling_mode_property, 0);

        connector->scaling_mode_property = scaling_mode_property;

        return 0;
}
EXPORT_SYMBOL(drm_connector_attach_scaling_mode_property);

/**
 * drm_mode_create_aspect_ratio_property - create aspect ratio property
 * @dev: DRM device
 *
 * Called by a driver the first time it's needed, must be attached to desired
 * connectors.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_create_aspect_ratio_property(struct drm_device *dev)
{
        if (dev->mode_config.aspect_ratio_property)
                return 0;

        dev->mode_config.aspect_ratio_property =
                drm_property_create_enum(dev, 0, "aspect ratio",
                                drm_aspect_ratio_enum_list,
                                ARRAY_SIZE(drm_aspect_ratio_enum_list));

        if (dev->mode_config.aspect_ratio_property == NULL)
                return -ENOMEM;

        return 0;
}
EXPORT_SYMBOL(drm_mode_create_aspect_ratio_property);

/**
 * drm_mode_create_suggested_offset_properties - create suggests offset properties
 * @dev: DRM device
 *
 * Create the the suggested x/y offset property for connectors.
 */
int drm_mode_create_suggested_offset_properties(struct drm_device *dev)
{
        if (dev->mode_config.suggested_x_property && dev->mode_config.suggested_y_property)
                return 0;

        dev->mode_config.suggested_x_property =
                drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE, "suggested X", 0, 0xffffffff);

        dev->mode_config.suggested_y_property =
                drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE, "suggested Y", 0, 0xffffffff);

        if (dev->mode_config.suggested_x_property == NULL ||
            dev->mode_config.suggested_y_property == NULL)
                return -ENOMEM;
        return 0;
}
EXPORT_SYMBOL(drm_mode_create_suggested_offset_properties);

/**
 * drm_mode_connector_set_path_property - set tile property on connector
 * @connector: connector to set property on.
 * @path: path to use for property; must not be NULL.
 *
 * This creates a property to expose to userspace to specify a
 * connector path. This is mainly used for DisplayPort MST where
 * connectors have a topology and we want to allow userspace to give
 * them more meaningful names.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_connector_set_path_property(struct drm_connector *connector,
                                         const char *path)
{
        struct drm_device *dev = connector->dev;
        int ret;

        ret = drm_property_replace_global_blob(dev,
                                               &connector->path_blob_ptr,
                                               strlen(path) + 1,
                                               path,
                                               &connector->base,
                                               dev->mode_config.path_property);
        return ret;
}
EXPORT_SYMBOL(drm_mode_connector_set_path_property);

/**
 * drm_mode_connector_set_tile_property - set tile property on connector
 * @connector: connector to set property on.
 *
 * This looks up the tile information for a connector, and creates a
 * property for userspace to parse if it exists. The property is of
 * the form of 8 integers using ':' as a separator.
 *
 * Returns:
 * Zero on success, errno on failure.
 */
int drm_mode_connector_set_tile_property(struct drm_connector *connector)
{
        struct drm_device *dev = connector->dev;
        char tile[256];
        int ret;

        if (!connector->has_tile) {
                ret  = drm_property_replace_global_blob(dev,
                                                        &connector->tile_blob_ptr,
                                                        0,
                                                        NULL,
                                                        &connector->base,
                                                        dev->mode_config.tile_property);
                return ret;
        }

        snprintf(tile, 256, "%d:%d:%d:%d:%d:%d:%d:%d",
                 connector->tile_group->id, connector->tile_is_single_monitor,
                 connector->num_h_tile, connector->num_v_tile,
                 connector->tile_h_loc, connector->tile_v_loc,
                 connector->tile_h_size, connector->tile_v_size);

        ret = drm_property_replace_global_blob(dev,
                                               &connector->tile_blob_ptr,
                                               strlen(tile) + 1,
                                               tile,
                                               &connector->base,
                                               dev->mode_config.tile_property);
        return ret;
}
EXPORT_SYMBOL(drm_mode_connector_set_tile_property);

/**
 * drm_mode_connector_update_edid_property - update the edid property of a connector
 * @connector: drm connector
 * @edid: new value of the edid property
 *
 * This function creates a new blob modeset object and assigns its id to the
 * connector's edid property.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_connector_update_edid_property(struct drm_connector *connector,
                                            const struct edid *edid)
{
        struct drm_device *dev = connector->dev;
        size_t size = 0;
        int ret;

        /* ignore requests to set edid when overridden */
        if (connector->override_edid)
                return 0;

        if (edid)
                size = EDID_LENGTH * (1 + edid->extensions);

        ret = drm_property_replace_global_blob(dev,
                                               &connector->edid_blob_ptr,
                                               size,
                                               edid,
                                               &connector->base,
                                               dev->mode_config.edid_property);
        return ret;
}
EXPORT_SYMBOL(drm_mode_connector_update_edid_property);

/**
 * drm_mode_connector_set_link_status_property - Set link status property of a connector
 * @connector: drm connector
 * @link_status: new value of link status property (0: Good, 1: Bad)
 *
 * In usual working scenario, this link status property will always be set to
 * "GOOD". If something fails during or after a mode set, the kernel driver
 * may set this link status property to "BAD". The caller then needs to send a
 * hotplug uevent for userspace to re-check the valid modes through
 * GET_CONNECTOR_IOCTL and retry modeset.
 *
 * Note: Drivers cannot rely on userspace to support this property and
 * issue a modeset. As such, they may choose to handle issues (like
 * re-training a link) without userspace's intervention.
 *
 * The reason for adding this property is to handle link training failures, but
 * it is not limited to DP or link training. For example, if we implement
 * asynchronous setcrtc, this property can be used to report any failures in that.
 */
void drm_mode_connector_set_link_status_property(struct drm_connector *connector,
                                                 uint64_t link_status)
{
        struct drm_device *dev = connector->dev;

        drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
        connector->state->link_status = link_status;
        drm_modeset_unlock(&dev->mode_config.connection_mutex);
}
EXPORT_SYMBOL(drm_mode_connector_set_link_status_property);

int drm_mode_connector_set_obj_prop(struct drm_mode_object *obj,
                                    struct drm_property *property,
                                    uint64_t value)
{
        int ret = -EINVAL;
        struct drm_connector *connector = obj_to_connector(obj);

        /* Do DPMS ourselves */
        if (property == connector->dev->mode_config.dpms_property) {
                ret = (*connector->funcs->dpms)(connector, (int)value);
        } else if (connector->funcs->set_property)
                ret = connector->funcs->set_property(connector, property, value);

        /* store the property value if successful */
        if (!ret)
                drm_object_property_set_value(&connector->base, property, value);
        return ret;
}

int drm_mode_connector_property_set_ioctl(struct drm_device *dev,
                                       void *data, struct drm_file *file_priv)
{
        struct drm_mode_connector_set_property *conn_set_prop = data;
        struct drm_mode_obj_set_property obj_set_prop = {
                .value = conn_set_prop->value,
                .prop_id = conn_set_prop->prop_id,
                .obj_id = conn_set_prop->connector_id,
                .obj_type = DRM_MODE_OBJECT_CONNECTOR
        };

        /* It does all the locking and checking we need */
        return drm_mode_obj_set_property_ioctl(dev, &obj_set_prop, file_priv);
}

static struct drm_encoder *drm_connector_get_encoder(struct drm_connector *connector)
{
        /* For atomic drivers only state objects are synchronously updated and
         * protected by modeset locks, so check those first. */
        if (connector->state)
                return connector->state->best_encoder;
        return connector->encoder;
}

static bool drm_mode_expose_to_userspace(const struct drm_display_mode *mode,
                                         const struct drm_file *file_priv)
{
        /*
         * If user-space hasn't configured the driver to expose the stereo 3D
         * modes, don't expose them.
         */
        if (!file_priv->stereo_allowed && drm_mode_is_stereo(mode))
                return false;

        return true;
}

int drm_mode_getconnector(struct drm_device *dev, void *data,
                          struct drm_file *file_priv)
{
        struct drm_mode_get_connector *out_resp = data;
        struct drm_connector *connector;
        struct drm_encoder *encoder;
        struct drm_display_mode *mode;
        int mode_count = 0;
        int encoders_count = 0;
        int ret = 0;
        int copied = 0;
        int i;
        struct drm_mode_modeinfo u_mode;
        struct drm_mode_modeinfo __user *mode_ptr;
        uint32_t __user *encoder_ptr;

        if (!drm_core_check_feature(dev, DRIVER_MODESET))
                return -EINVAL;

        memset(&u_mode, 0, sizeof(struct drm_mode_modeinfo));

        connector = drm_connector_lookup(dev, out_resp->connector_id);
        if (!connector)
                return -ENOENT;

        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
                if (connector->encoder_ids[i] != 0)
                        encoders_count++;

        if ((out_resp->count_encoders >= encoders_count) && encoders_count) {
                copied = 0;
                encoder_ptr = (uint32_t __user *)(unsigned long)(out_resp->encoders_ptr);
                for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
                        if (connector->encoder_ids[i] != 0) {
                                if (put_user(connector->encoder_ids[i],
                                             encoder_ptr + copied)) {
                                        ret = -EFAULT;
                                        goto out;
                                }
                                copied++;
                        }
                }
        }
        out_resp->count_encoders = encoders_count;

        out_resp->connector_id = connector->base.id;
        out_resp->connector_type = connector->connector_type;
        out_resp->connector_type_id = connector->connector_type_id;

        mutex_lock(&dev->mode_config.mutex);
        if (out_resp->count_modes == 0) {
                connector->funcs->fill_modes(connector,
                                             dev->mode_config.max_width,
                                             dev->mode_config.max_height);
        }

        out_resp->mm_width = connector->display_info.width_mm;
        out_resp->mm_height = connector->display_info.height_mm;
        out_resp->subpixel = connector->display_info.subpixel_order;
        out_resp->connection = connector->status;

        /* delayed so we get modes regardless of pre-fill_modes state */
        list_for_each_entry(mode, &connector->modes, head)
                if (drm_mode_expose_to_userspace(mode, file_priv))
                        mode_count++;

        /*
         * This ioctl is called twice, once to determine how much space is
         * needed, and the 2nd time to fill it.
         */
        if ((out_resp->count_modes >= mode_count) && mode_count) {
                copied = 0;
                mode_ptr = (struct drm_mode_modeinfo __user *)(unsigned long)out_resp->modes_ptr;
                list_for_each_entry(mode, &connector->modes, head) {
                        if (!drm_mode_expose_to_userspace(mode, file_priv))
                                continue;

                        drm_mode_convert_to_umode(&u_mode, mode);
                        if (copy_to_user(mode_ptr + copied,
                                         &u_mode, sizeof(u_mode))) {
                                ret = -EFAULT;
                                mutex_unlock(&dev->mode_config.mutex);

                                goto out;
                        }
                        copied++;
                }
        }
        out_resp->count_modes = mode_count;
        mutex_unlock(&dev->mode_config.mutex);

        drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
        encoder = drm_connector_get_encoder(connector);
        if (encoder)
                out_resp->encoder_id = encoder->base.id;
        else
                out_resp->encoder_id = 0;

        /* Only grab properties after probing, to make sure EDID and other
         * properties reflect the latest status. */
        ret = drm_mode_object_get_properties(&connector->base, file_priv->atomic,
                        (uint32_t __user *)(unsigned long)(out_resp->props_ptr),
                        (uint64_t __user *)(unsigned long)(out_resp->prop_values_ptr),
                        &out_resp->count_props);
        drm_modeset_unlock(&dev->mode_config.connection_mutex);

out:
        drm_connector_put(connector);

        return ret;
}


/**
 * DOC: Tile group
 *
 * Tile groups are used to represent tiled monitors with a unique integer
 * identifier. Tiled monitors using DisplayID v1.3 have a unique 8-byte handle,
 * we store this in a tile group, so we have a common identifier for all tiles
 * in a monitor group. The property is called "TILE". Drivers can manage tile
 * groups using drm_mode_create_tile_group(), drm_mode_put_tile_group() and
 * drm_mode_get_tile_group(). But this is only needed for internal panels where
 * the tile group information is exposed through a non-standard way.
 */

static void drm_tile_group_free(struct kref *kref)
{
        struct drm_tile_group *tg = container_of(kref, struct drm_tile_group, refcount);
        struct drm_device *dev = tg->dev;
        mutex_lock(&dev->mode_config.idr_mutex);
        idr_remove(&dev->mode_config.tile_idr, tg->id);
        mutex_unlock(&dev->mode_config.idr_mutex);
        kfree(tg);
}

/**
 * drm_mode_put_tile_group - drop a reference to a tile group.
 * @dev: DRM device
 * @tg: tile group to drop reference to.
 *
 * drop reference to tile group and free if 0.
 */
void drm_mode_put_tile_group(struct drm_device *dev,
                             struct drm_tile_group *tg)
{
        kref_put(&tg->refcount, drm_tile_group_free);
}
EXPORT_SYMBOL(drm_mode_put_tile_group);

/**
 * drm_mode_get_tile_group - get a reference to an existing tile group
 * @dev: DRM device
 * @topology: 8-bytes unique per monitor.
 *
 * Use the unique bytes to get a reference to an existing tile group.
 *
 * RETURNS:
 * tile group or NULL if not found.
 */
struct drm_tile_group *drm_mode_get_tile_group(struct drm_device *dev,
                                               char topology[8])
{
        struct drm_tile_group *tg;
        int id;
        mutex_lock(&dev->mode_config.idr_mutex);
        idr_for_each_entry(&dev->mode_config.tile_idr, tg, id) {
                if (!memcmp(tg->group_data, topology, 8)) {
                        if (!kref_get_unless_zero(&tg->refcount))
                                tg = NULL;
                        mutex_unlock(&dev->mode_config.idr_mutex);
                        return tg;
                }
        }
        mutex_unlock(&dev->mode_config.idr_mutex);
        return NULL;
}
EXPORT_SYMBOL(drm_mode_get_tile_group);

/**
 * drm_mode_create_tile_group - create a tile group from a displayid description
 * @dev: DRM device
 * @topology: 8-bytes unique per monitor.
 *
 * Create a tile group for the unique monitor, and get a unique
 * identifier for the tile group.
 *
 * RETURNS:
 * new tile group or error.
 */
struct drm_tile_group *drm_mode_create_tile_group(struct drm_device *dev,
                                                  char topology[8])
{
        struct drm_tile_group *tg;
        int ret;

        tg = kzalloc(sizeof(*tg), GFP_KERNEL);
        if (!tg)
                return ERR_PTR(-ENOMEM);

        kref_init(&tg->refcount);
        memcpy(tg->group_data, topology, 8);
        tg->dev = dev;

        mutex_lock(&dev->mode_config.idr_mutex);
        ret = idr_alloc(&dev->mode_config.tile_idr, tg, 1, 0, GFP_KERNEL);
        if (ret >= 0) {
                tg->id = ret;
        } else {
                kfree(tg);
                tg = ERR_PTR(ret);
        }

        mutex_unlock(&dev->mode_config.idr_mutex);
        return tg;
}
EXPORT_SYMBOL(drm_mode_create_tile_group);