// SPDX-License-Identifier: GPL-2.0
/*
 * (C) COPYRIGHT 2018 ARM Limited. All rights reserved.
 * Author: James.Qian.Wang <james.qian.wang@arm.com>
 *
 */
#include <linux/interrupt.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_fbdev_dma.h>
#include <drm/drm_gem_dma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_managed.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_vblank.h>

#include "komeda_dev.h"
#include "komeda_framebuffer.h"
#include "komeda_kms.h"

DEFINE_DRM_GEM_DMA_FOPS(komeda_cma_fops);

static int komeda_gem_dma_dumb_create(struct drm_file *file,
                                      struct drm_device *dev,
                                      struct drm_mode_create_dumb *args)
{
        struct komeda_dev *mdev = dev->dev_private;
        u32 pitch = DIV_ROUND_UP(args->width * args->bpp, 8);

        args->pitch = ALIGN(pitch, mdev->chip.bus_width);

        return drm_gem_dma_dumb_create_internal(file, dev, args);
}

static irqreturn_t komeda_kms_irq_handler(int irq, void *data)
{
        struct drm_device *drm = data;
        struct komeda_dev *mdev = drm->dev_private;
        struct komeda_kms_dev *kms = to_kdev(drm);
        struct komeda_events evts;
        irqreturn_t status;
        u32 i;

        /* Call into the CHIP to recognize events */
        memset(&evts, 0, sizeof(evts));
        status = mdev->funcs->irq_handler(mdev, &evts);

        komeda_print_events(&evts, drm);

        /* Notify the crtc to handle the events */
        for (i = 0; i < kms->n_crtcs; i++)
                komeda_crtc_handle_event(&kms->crtcs[i], &evts);

        return status;
}

static const struct drm_driver komeda_kms_driver = {
        .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
        DRM_GEM_DMA_DRIVER_OPS_WITH_DUMB_CREATE(komeda_gem_dma_dumb_create),
        DRM_FBDEV_DMA_DRIVER_OPS,
        .fops = &komeda_cma_fops,
        .name = "komeda",
        .desc = "Arm Komeda Display Processor driver",
        .major = 0,
        .minor = 1,
};

static void komeda_kms_atomic_commit_hw_done(struct drm_atomic_state *state)
{
        struct drm_device *dev = state->dev;
        struct komeda_kms_dev *kms = to_kdev(dev);
        int i;

        for (i = 0; i < kms->n_crtcs; i++) {
                struct komeda_crtc *kcrtc = &kms->crtcs[i];

                if (kcrtc->base.state->active) {
                        struct completion *flip_done = NULL;
                        if (kcrtc->base.state->event)
                                flip_done = kcrtc->base.state->event->base.completion;
                        komeda_crtc_flush_and_wait_for_flip_done(kcrtc, flip_done);
                }
        }
        drm_atomic_helper_commit_hw_done(state);
}

static void komeda_kms_commit_tail(struct drm_atomic_state *old_state)
{
        struct drm_device *dev = old_state->dev;
        bool fence_cookie = dma_fence_begin_signalling();

        drm_atomic_helper_commit_modeset_disables(dev, old_state);

        drm_atomic_helper_commit_planes(dev, old_state,
                                        DRM_PLANE_COMMIT_ACTIVE_ONLY);

        drm_atomic_helper_commit_modeset_enables(dev, old_state);

        komeda_kms_atomic_commit_hw_done(old_state);

        drm_atomic_helper_wait_for_flip_done(dev, old_state);

        dma_fence_end_signalling(fence_cookie);

        drm_atomic_helper_cleanup_planes(dev, old_state);
}

static const struct drm_mode_config_helper_funcs komeda_mode_config_helpers = {
        .atomic_commit_tail = komeda_kms_commit_tail,
};

static int komeda_plane_state_list_add(struct drm_plane_state *plane_st,
                                       struct list_head *zorder_list)
{
        struct komeda_plane_state *new = to_kplane_st(plane_st);
        struct komeda_plane_state *node, *last;

        last = list_empty(zorder_list) ?
               NULL : list_last_entry(zorder_list, typeof(*last), zlist_node);

        /* Considering the list sequence is zpos increasing, so if list is empty
         * or the zpos of new node bigger than the last node in list, no need
         * loop and just insert the new one to the tail of the list.
         */
        if (!last || (new->base.zpos > last->base.zpos)) {
                list_add_tail(&new->zlist_node, zorder_list);
                return 0;
        }

        /* Build the list by zpos increasing */
        list_for_each_entry(node, zorder_list, zlist_node) {
                if (new->base.zpos < node->base.zpos) {
                        list_add_tail(&new->zlist_node, &node->zlist_node);
                        break;
                } else if (node->base.zpos == new->base.zpos) {
                        struct drm_plane *a = node->base.plane;
                        struct drm_plane *b = new->base.plane;

                        /* Komeda doesn't support setting a same zpos for
                         * different planes.
                         */
                        DRM_DEBUG_ATOMIC("PLANE: %s and PLANE: %s are configured same zpos: %d.\n",
                                         a->name, b->name, node->base.zpos);
                        return -EINVAL;
                }
        }

        return 0;
}

static int komeda_crtc_normalize_zpos(struct drm_crtc *crtc,
                                      struct drm_crtc_state *crtc_st)
{
        struct drm_atomic_state *state = crtc_st->state;
        struct komeda_crtc *kcrtc = to_kcrtc(crtc);
        struct komeda_crtc_state *kcrtc_st = to_kcrtc_st(crtc_st);
        struct komeda_plane_state *kplane_st;
        struct drm_plane_state *plane_st;
        struct drm_plane *plane;
        struct list_head zorder_list;
        int order = 0, err;
        u32 slave_zpos = 0;

        DRM_DEBUG_ATOMIC("[CRTC:%d:%s] calculating normalized zpos values\n",
                         crtc->base.id, crtc->name);

        INIT_LIST_HEAD(&zorder_list);

        /* This loop also added all effected planes into the new state */
        drm_for_each_plane_mask(plane, crtc->dev, crtc_st->plane_mask) {
                plane_st = drm_atomic_get_plane_state(state, plane);
                if (IS_ERR(plane_st))
                        return PTR_ERR(plane_st);

                /* Build a list by zpos increasing */
                err = komeda_plane_state_list_add(plane_st, &zorder_list);
                if (err)
                        return err;
        }

        kcrtc_st->max_slave_zorder = 0;

        list_for_each_entry(kplane_st, &zorder_list, zlist_node) {
                plane_st = &kplane_st->base;
                plane = plane_st->plane;

                plane_st->normalized_zpos = order++;
                /* When layer_split has been enabled, one plane will be handled
                 * by two separated komeda layers (left/right), which may needs
                 * two zorders.
                 * - zorder: for left_layer for left display part.
                 * - zorder + 1: will be reserved for right layer.
                 */
                if (to_kplane_st(plane_st)->layer_split)
                        order++;

                DRM_DEBUG_ATOMIC("[PLANE:%d:%s] zpos:%d, normalized zpos: %d\n",
                                 plane->base.id, plane->name,
                                 plane_st->zpos, plane_st->normalized_zpos);

                /* calculate max slave zorder */
                if (has_bit(drm_plane_index(plane), kcrtc->slave_planes)) {
                        slave_zpos = plane_st->normalized_zpos;
                        if (to_kplane_st(plane_st)->layer_split)
                                slave_zpos++;
                        kcrtc_st->max_slave_zorder =
                                max(slave_zpos, kcrtc_st->max_slave_zorder);
                }
        }

        crtc_st->zpos_changed = true;

        return 0;
}

static int komeda_kms_check(struct drm_device *dev,
                            struct drm_atomic_state *state)
{
        struct drm_crtc *crtc;
        struct drm_crtc_state *new_crtc_st;
        int i, err;

        err = drm_atomic_helper_check_modeset(dev, state);
        if (err)
                return err;

        /* Komeda need to re-calculate resource assumption in every commit
         * so need to add all affected_planes (even unchanged) to
         * drm_atomic_state.
         */
        for_each_new_crtc_in_state(state, crtc, new_crtc_st, i) {
                err = drm_atomic_add_affected_planes(state, crtc);
                if (err)
                        return err;

                err = komeda_crtc_normalize_zpos(crtc, new_crtc_st);
                if (err)
                        return err;
        }

        err = drm_atomic_helper_check_planes(dev, state);
        if (err)
                return err;

        return 0;
}

static const struct drm_mode_config_funcs komeda_mode_config_funcs = {
        .fb_create              = komeda_fb_create,
        .atomic_check           = komeda_kms_check,
        .atomic_commit          = drm_atomic_helper_commit,
};

static void komeda_kms_mode_config_init(struct komeda_kms_dev *kms,
                                        struct komeda_dev *mdev)
{
        struct drm_mode_config *config = &kms->base.mode_config;

        drm_mode_config_init(&kms->base);

        komeda_kms_setup_crtcs(kms, mdev);

        /* Get value from dev */
        config->min_width       = 0;
        config->min_height      = 0;
        config->max_width       = 4096;
        config->max_height      = 4096;

        config->funcs = &komeda_mode_config_funcs;
        config->helper_private = &komeda_mode_config_helpers;
}

struct komeda_kms_dev *komeda_kms_attach(struct komeda_dev *mdev)
{
        struct komeda_kms_dev *kms;
        struct drm_device *drm;
        int err;

        kms = devm_drm_dev_alloc(mdev->dev, &komeda_kms_driver,
                                 struct komeda_kms_dev, base);
        if (IS_ERR(kms))
                return kms;

        drm = &kms->base;

        drm->dev_private = mdev;

        komeda_kms_mode_config_init(kms, mdev);

        err = komeda_kms_add_private_objs(kms, mdev);
        if (err)
                goto cleanup_mode_config;

        err = komeda_kms_add_planes(kms, mdev);
        if (err)
                goto cleanup_mode_config;

        err = drm_vblank_init(drm, kms->n_crtcs);
        if (err)
                goto cleanup_mode_config;

        err = komeda_kms_add_crtcs(kms, mdev);
        if (err)
                goto cleanup_mode_config;

        err = komeda_kms_add_wb_connectors(kms, mdev);
        if (err)
                goto cleanup_mode_config;

        drm_mode_config_reset(drm);

        err = devm_request_irq(drm->dev, mdev->irq,
                               komeda_kms_irq_handler, IRQF_SHARED,
                               drm->driver->name, drm);
        if (err)
                goto cleanup_mode_config;

        drm_kms_helper_poll_init(drm);

        err = drm_dev_register(drm, 0);
        if (err)
                goto free_interrupts;

        return kms;

free_interrupts:
        drm_kms_helper_poll_fini(drm);
cleanup_mode_config:
        drm_mode_config_cleanup(drm);
        komeda_kms_cleanup_private_objs(kms);
        drm->dev_private = NULL;
        return ERR_PTR(err);
}

void komeda_kms_detach(struct komeda_kms_dev *kms)
{
        struct drm_device *drm = &kms->base;

        drm_dev_unregister(drm);
        drm_kms_helper_poll_fini(drm);
        drm_atomic_helper_shutdown(drm);
        drm_mode_config_cleanup(drm);
        komeda_kms_cleanup_private_objs(kms);
        drm->dev_private = NULL;
}

void komeda_kms_shutdown(struct komeda_kms_dev *kms)
{
        struct drm_device *drm = &kms->base;

        drm_atomic_helper_shutdown(drm);
}