/*
 * Copyright (C) 2016 Noralf Trønnes
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <drm/drmP.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_plane_helper.h>
#include <drm/drm_simple_kms_helper.h>
#include <linux/slab.h>

/**
 * DOC: overview
 *
 * This helper library provides helpers for drivers for simple display
 * hardware.
 *
 * drm_simple_display_pipe_init() initializes a simple display pipeline
 * which has only one full-screen scanout buffer feeding one output. The
 * pipeline is represented by &struct drm_simple_display_pipe and binds
 * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
 * entity. Some flexibility for code reuse is provided through a separately
 * allocated &drm_connector object and supporting optional &drm_bridge
 * encoder drivers.
 */

static const struct drm_encoder_funcs drm_simple_kms_encoder_funcs = {
        .destroy = drm_encoder_cleanup,
};

static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
                                     struct drm_crtc_state *state)
{
        bool has_primary = state->plane_mask &
                           BIT(drm_plane_index(crtc->primary));

        /* We always want to have an active plane with an active CRTC */
        if (has_primary != state->enable)
                return -EINVAL;

        return drm_atomic_add_affected_planes(state->state, crtc);
}

static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
                                       struct drm_crtc_state *old_state)
{
        struct drm_simple_display_pipe *pipe;

        pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
        if (!pipe->funcs || !pipe->funcs->enable)
                return;

        pipe->funcs->enable(pipe, crtc->state);
}

static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
                                        struct drm_crtc_state *old_state)
{
        struct drm_simple_display_pipe *pipe;

        pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
        if (!pipe->funcs || !pipe->funcs->disable)
                return;

        pipe->funcs->disable(pipe);
}

static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
        .atomic_check = drm_simple_kms_crtc_check,
        .atomic_enable = drm_simple_kms_crtc_enable,
        .atomic_disable = drm_simple_kms_crtc_disable,
};

static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
        .reset = drm_atomic_helper_crtc_reset,
        .destroy = drm_crtc_cleanup,
        .set_config = drm_atomic_helper_set_config,
        .page_flip = drm_atomic_helper_page_flip,
        .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
        .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
};

static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
                                        struct drm_plane_state *plane_state)
{
        struct drm_rect clip = { 0 };
        struct drm_simple_display_pipe *pipe;
        struct drm_crtc_state *crtc_state;
        int ret;

        pipe = container_of(plane, struct drm_simple_display_pipe, plane);
        crtc_state = drm_atomic_get_new_crtc_state(plane_state->state,
                                                   &pipe->crtc);
        if (!crtc_state->enable)
                return 0; /* nothing to check when disabling or disabled */

        clip.x2 = crtc_state->adjusted_mode.hdisplay;
        clip.y2 = crtc_state->adjusted_mode.vdisplay;

        ret = drm_plane_helper_check_state(plane_state, &clip,
                                           DRM_PLANE_HELPER_NO_SCALING,
                                           DRM_PLANE_HELPER_NO_SCALING,
                                           false, true);
        if (ret)
                return ret;

        if (!plane_state->visible)
                return -EINVAL;

        if (!pipe->funcs || !pipe->funcs->check)
                return 0;

        return pipe->funcs->check(pipe, plane_state, crtc_state);
}

static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
                                        struct drm_plane_state *old_pstate)
{
        struct drm_simple_display_pipe *pipe;

        pipe = container_of(plane, struct drm_simple_display_pipe, plane);
        if (!pipe->funcs || !pipe->funcs->update)
                return;

        pipe->funcs->update(pipe, old_pstate);
}

static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
                                           struct drm_plane_state *state)
{
        struct drm_simple_display_pipe *pipe;

        pipe = container_of(plane, struct drm_simple_display_pipe, plane);
        if (!pipe->funcs || !pipe->funcs->prepare_fb)
                return 0;

        return pipe->funcs->prepare_fb(pipe, state);
}

static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
                                            struct drm_plane_state *state)
{
        struct drm_simple_display_pipe *pipe;

        pipe = container_of(plane, struct drm_simple_display_pipe, plane);
        if (!pipe->funcs || !pipe->funcs->cleanup_fb)
                return;

        pipe->funcs->cleanup_fb(pipe, state);
}

static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
        .prepare_fb = drm_simple_kms_plane_prepare_fb,
        .cleanup_fb = drm_simple_kms_plane_cleanup_fb,
        .atomic_check = drm_simple_kms_plane_atomic_check,
        .atomic_update = drm_simple_kms_plane_atomic_update,
};

static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
        .update_plane           = drm_atomic_helper_update_plane,
        .disable_plane          = drm_atomic_helper_disable_plane,
        .destroy                = drm_plane_cleanup,
        .reset                  = drm_atomic_helper_plane_reset,
        .atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
        .atomic_destroy_state   = drm_atomic_helper_plane_destroy_state,
};

/**
 * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
 * @pipe: simple display pipe object
 * @bridge: bridge to attach
 *
 * Makes it possible to still use the drm_simple_display_pipe helpers when
 * a DRM bridge has to be used.
 *
 * Note that you probably want to initialize the pipe by passing a NULL
 * connector to drm_simple_display_pipe_init().
 *
 * Returns:
 * Zero on success, negative error code on failure.
 */
int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
                                          struct drm_bridge *bridge)
{
        return drm_bridge_attach(&pipe->encoder, bridge, NULL);
}
EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);

/**
 * drm_simple_display_pipe_init - Initialize a simple display pipeline
 * @dev: DRM device
 * @pipe: simple display pipe object to initialize
 * @funcs: callbacks for the display pipe (optional)
 * @formats: array of supported formats (DRM_FORMAT\_\*)
 * @format_count: number of elements in @formats
 * @format_modifiers: array of formats modifiers
 * @connector: connector to attach and register (optional)
 *
 * Sets up a display pipeline which consist of a really simple
 * plane-crtc-encoder pipe.
 *
 * If a connector is supplied, the pipe will be coupled with the provided
 * connector. You may supply a NULL connector when using drm bridges, that
 * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
 *
 * Teardown of a simple display pipe is all handled automatically by the drm
 * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
 * release the memory for the structure themselves.
 *
 * Returns:
 * Zero on success, negative error code on failure.
 */
int drm_simple_display_pipe_init(struct drm_device *dev,
                        struct drm_simple_display_pipe *pipe,
                        const struct drm_simple_display_pipe_funcs *funcs,
                        const uint32_t *formats, unsigned int format_count,
                        const uint64_t *format_modifiers,
                        struct drm_connector *connector)
{
        struct drm_encoder *encoder = &pipe->encoder;
        struct drm_plane *plane = &pipe->plane;
        struct drm_crtc *crtc = &pipe->crtc;
        int ret;

        pipe->connector = connector;
        pipe->funcs = funcs;

        drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
        ret = drm_universal_plane_init(dev, plane, 0,
                                       &drm_simple_kms_plane_funcs,
                                       formats, format_count,
                                       format_modifiers,
                                       DRM_PLANE_TYPE_PRIMARY, NULL);
        if (ret)
                return ret;

        drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
        ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
                                        &drm_simple_kms_crtc_funcs, NULL);
        if (ret)
                return ret;

        encoder->possible_crtcs = 1 << drm_crtc_index(crtc);
        ret = drm_encoder_init(dev, encoder, &drm_simple_kms_encoder_funcs,
                               DRM_MODE_ENCODER_NONE, NULL);
        if (ret || !connector)
                return ret;

        return drm_mode_connector_attach_encoder(connector, encoder);
}
EXPORT_SYMBOL(drm_simple_display_pipe_init);

MODULE_LICENSE("GPL");