// 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);
}
