// SPDX-License-Identifier: MIT

#include <drm/drm_client.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_print.h>

#include "drm_client_internal.h"

/*
 * struct drm_client_funcs
 */

static void drm_fbdev_client_free(struct drm_client_dev *client)
{
        struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);

        drm_fb_helper_unprepare(fb_helper);
        kfree(fb_helper);
}

static void drm_fbdev_client_unregister(struct drm_client_dev *client)
{
        struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);

        if (fb_helper->info) {
                /*
                 * Fully probed framebuffer device
                 */
                drm_fb_helper_unregister_info(fb_helper);
        } else {
                /*
                 * Partially initialized client, no framebuffer device yet
                 */
                drm_client_release(&fb_helper->client);
        }
}

static int drm_fbdev_client_restore(struct drm_client_dev *client, bool force)
{
        struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);

        drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);

        return 0;
}

static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
{
        struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
        struct drm_device *dev = client->dev;
        int ret;

        if (dev->fb_helper)
                return drm_fb_helper_hotplug_event(dev->fb_helper);

        ret = drm_fb_helper_init(dev, fb_helper);
        if (ret)
                goto err_drm_err;

        if (!drm_drv_uses_atomic_modeset(dev))
                drm_helper_disable_unused_functions(dev);

        ret = drm_fb_helper_initial_config(fb_helper);
        if (ret)
                goto err_drm_fb_helper_fini;

        return 0;

err_drm_fb_helper_fini:
        drm_fb_helper_fini(fb_helper);
err_drm_err:
        drm_err(dev, "fbdev: Failed to setup emulation (ret=%d)\n", ret);
        return ret;
}

static int drm_fbdev_client_suspend(struct drm_client_dev *client)
{
        struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);

        drm_fb_helper_set_suspend_unlocked(fb_helper, true);

        return 0;
}

static int drm_fbdev_client_resume(struct drm_client_dev *client)
{
        struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);

        drm_fb_helper_set_suspend_unlocked(fb_helper, false);

        return 0;
}

static const struct drm_client_funcs drm_fbdev_client_funcs = {
        .owner          = THIS_MODULE,
        .free           = drm_fbdev_client_free,
        .unregister     = drm_fbdev_client_unregister,
        .restore        = drm_fbdev_client_restore,
        .hotplug        = drm_fbdev_client_hotplug,
        .suspend        = drm_fbdev_client_suspend,
        .resume         = drm_fbdev_client_resume,
};

/**
 * drm_fbdev_client_setup() - Setup fbdev emulation
 * @dev: DRM device
 * @format: Preferred color format for the device. DRM_FORMAT_XRGB8888
 *          is used if this is zero.
 *
 * This function sets up fbdev emulation. Restore, hotplug events and
 * teardown are all taken care of. Drivers that do suspend/resume need
 * to call drm_client_dev_suspend() and drm_client_dev_resume() by
 * themselves. Simple drivers might use drm_mode_config_helper_suspend().
 *
 * This function is safe to call even when there are no connectors present.
 * Setup will be retried on the next hotplug event.
 *
 * The fbdev client is destroyed by drm_dev_unregister().
 *
 * Returns:
 * 0 on success, or a negative errno code otherwise.
 */
int drm_fbdev_client_setup(struct drm_device *dev, const struct drm_format_info *format)
{
        struct drm_fb_helper *fb_helper;
        unsigned int color_mode;
        int ret;

        /* TODO: Use format info throughout DRM */
        if (format) {
                unsigned int bpp = drm_format_info_bpp(format, 0);

                switch (bpp) {
                case 16:
                        color_mode = format->depth; // could also be 15
                        break;
                default:
                        color_mode = bpp;
                }
        } else {
                switch (dev->mode_config.preferred_depth) {
                case 0:
                case 24:
                        color_mode = 32;
                        break;
                default:
                        color_mode = dev->mode_config.preferred_depth;
                }
        }

        drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
        drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");

        fb_helper = kzalloc_obj(*fb_helper);
        if (!fb_helper)
                return -ENOMEM;
        drm_fb_helper_prepare(dev, fb_helper, color_mode, NULL);

        ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);
        if (ret) {
                drm_err(dev, "Failed to register client: %d\n", ret);
                goto err_drm_client_init;
        }

        drm_client_register(&fb_helper->client);

        return 0;

err_drm_client_init:
        drm_fb_helper_unprepare(fb_helper);
        kfree(fb_helper);
        return ret;
}