/*
 * Copyright (C) STMicroelectronics SA 2014
 * Author: Benjamin Gaignard <benjamin.gaignard@st.com> for STMicroelectronics.
 * License terms:  GNU General Public License (GPL), version 2
 */

#include <drm/drmP.h>

#include <linux/component.h>
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_platform.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_fb_cma_helper.h>

#include "sti_crtc.h"
#include "sti_drv.h"
#include "sti_plane.h"

#define DRIVER_NAME	"sti"
#define DRIVER_DESC	"STMicroelectronics SoC DRM"
#define DRIVER_DATE	"20140601"
#define DRIVER_MAJOR	1
#define DRIVER_MINOR	0

#define STI_MAX_FB_HEIGHT	4096
#define STI_MAX_FB_WIDTH	4096

static int sti_drm_fps_get(void *data, u64 *val)
{
	struct drm_device *drm_dev = data;
	struct drm_plane *p;
	unsigned int i = 0;

	*val = 0;
	list_for_each_entry(p, &drm_dev->mode_config.plane_list, head) {
		struct sti_plane *plane = to_sti_plane(p);

		*val |= plane->fps_info.output << i;
		i++;
	}

	return 0;
}

static int sti_drm_fps_set(void *data, u64 val)
{
	struct drm_device *drm_dev = data;
	struct drm_plane *p;
	unsigned int i = 0;

	list_for_each_entry(p, &drm_dev->mode_config.plane_list, head) {
		struct sti_plane *plane = to_sti_plane(p);

		plane->fps_info.output = (val >> i) & 1;
		i++;
	}

	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(sti_drm_fps_fops,
			sti_drm_fps_get, sti_drm_fps_set, "%llu\n");

static int sti_drm_fps_dbg_show(struct seq_file *s, void *data)
{
	struct drm_info_node *node = s->private;
	struct drm_device *dev = node->minor->dev;
	struct drm_plane *p;

	list_for_each_entry(p, &dev->mode_config.plane_list, head) {
		struct sti_plane *plane = to_sti_plane(p);

		seq_printf(s, "%s%s\n",
			   plane->fps_info.fps_str,
			   plane->fps_info.fips_str);
	}

	return 0;
}

static struct drm_info_list sti_drm_dbg_list[] = {
	{"fps_get", sti_drm_fps_dbg_show, 0},
};

static int sti_drm_debugfs_create(struct dentry *root,
				  struct drm_minor *minor,
				  const char *name,
				  const struct file_operations *fops)
{
	struct drm_device *dev = minor->dev;
	struct drm_info_node *node;
	struct dentry *ent;

	ent = debugfs_create_file(name, S_IRUGO | S_IWUSR, root, dev, fops);
	if (IS_ERR(ent))
		return PTR_ERR(ent);

	node = kmalloc(sizeof(*node), GFP_KERNEL);
	if (!node) {
		debugfs_remove(ent);
		return -ENOMEM;
	}

	node->minor = minor;
	node->dent = ent;
	node->info_ent = (void *)fops;

	mutex_lock(&minor->debugfs_lock);
	list_add(&node->list, &minor->debugfs_list);
	mutex_unlock(&minor->debugfs_lock);

	return 0;
}

static int sti_drm_dbg_init(struct drm_minor *minor)
{
	int ret;

	ret = drm_debugfs_create_files(sti_drm_dbg_list,
				       ARRAY_SIZE(sti_drm_dbg_list),
				       minor->debugfs_root, minor);
	if (ret)
		goto err;

	ret = sti_drm_debugfs_create(minor->debugfs_root, minor, "fps_show",
				     &sti_drm_fps_fops);
	if (ret)
		goto err;

	DRM_INFO("%s: debugfs installed\n", DRIVER_NAME);
	return 0;
err:
	DRM_ERROR("%s: cannot install debugfs\n", DRIVER_NAME);
	return ret;
}

void sti_drm_dbg_cleanup(struct drm_minor *minor)
{
	drm_debugfs_remove_files(sti_drm_dbg_list,
				 ARRAY_SIZE(sti_drm_dbg_list), minor);

	drm_debugfs_remove_files((struct drm_info_list *)&sti_drm_fps_fops,
				 1, minor);
}

static void sti_atomic_schedule(struct sti_private *private,
				struct drm_atomic_state *state)
{
	private->commit.state = state;
	schedule_work(&private->commit.work);
}

static void sti_atomic_complete(struct sti_private *private,
				struct drm_atomic_state *state)
{
	struct drm_device *drm = private->drm_dev;

	/*
	 * Everything below can be run asynchronously without the need to grab
	 * any modeset locks at all under one condition: It must be guaranteed
	 * that the asynchronous work has either been cancelled (if the driver
	 * supports it, which at least requires that the framebuffers get
	 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
	 * before the new state gets committed on the software side with
	 * drm_atomic_helper_swap_state().
	 *
	 * This scheme allows new atomic state updates to be prepared and
	 * checked in parallel to the asynchronous completion of the previous
	 * update. Which is important since compositors need to figure out the
	 * composition of the next frame right after having submitted the
	 * current layout.
	 */

	drm_atomic_helper_commit_modeset_disables(drm, state);
	drm_atomic_helper_commit_planes(drm, state, false);
	drm_atomic_helper_commit_modeset_enables(drm, state);

	drm_atomic_helper_wait_for_vblanks(drm, state);

	drm_atomic_helper_cleanup_planes(drm, state);
	drm_atomic_state_free(state);
}

static void sti_atomic_work(struct work_struct *work)
{
	struct sti_private *private = container_of(work,
			struct sti_private, commit.work);

	sti_atomic_complete(private, private->commit.state);
}

static int sti_atomic_commit(struct drm_device *drm,
			     struct drm_atomic_state *state, bool nonblock)
{
	struct sti_private *private = drm->dev_private;
	int err;

	err = drm_atomic_helper_prepare_planes(drm, state);
	if (err)
		return err;

	/* serialize outstanding nonblocking commits */
	mutex_lock(&private->commit.lock);
	flush_work(&private->commit.work);

	/*
	 * This is the point of no return - everything below never fails except
	 * when the hw goes bonghits. Which means we can commit the new state on
	 * the software side now.
	 */

	drm_atomic_helper_swap_state(state, true);

	if (nonblock)
		sti_atomic_schedule(private, state);
	else
		sti_atomic_complete(private, state);

	mutex_unlock(&private->commit.lock);
	return 0;
}

static void sti_output_poll_changed(struct drm_device *ddev)
{
	struct sti_private *private = ddev->dev_private;

	if (!ddev->mode_config.num_connector)
		return;

	if (private->fbdev) {
		drm_fbdev_cma_hotplug_event(private->fbdev);
		return;
	}

	private->fbdev = drm_fbdev_cma_init(ddev, 32,
					    ddev->mode_config.num_crtc,
					    ddev->mode_config.num_connector);
	if (IS_ERR(private->fbdev))
		private->fbdev = NULL;
}

static const struct drm_mode_config_funcs sti_mode_config_funcs = {
	.fb_create = drm_fb_cma_create,
	.output_poll_changed = sti_output_poll_changed,
	.atomic_check = drm_atomic_helper_check,
	.atomic_commit = sti_atomic_commit,
};

static void sti_mode_config_init(struct drm_device *dev)
{
	dev->mode_config.min_width = 0;
	dev->mode_config.min_height = 0;

	/*
	 * set max width and height as default value.
	 * this value would be used to check framebuffer size limitation
	 * at drm_mode_addfb().
	 */
	dev->mode_config.max_width = STI_MAX_FB_WIDTH;
	dev->mode_config.max_height = STI_MAX_FB_HEIGHT;

	dev->mode_config.funcs = &sti_mode_config_funcs;
}

static const struct file_operations sti_driver_fops = {
	.owner = THIS_MODULE,
	.open = drm_open,
	.mmap = drm_gem_cma_mmap,
	.poll = drm_poll,
	.read = drm_read,
	.unlocked_ioctl = drm_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = drm_compat_ioctl,
#endif
	.release = drm_release,
};

static struct drm_driver sti_driver = {
	.driver_features = DRIVER_HAVE_IRQ | DRIVER_MODESET |
	    DRIVER_GEM | DRIVER_PRIME | DRIVER_ATOMIC,
	.gem_free_object_unlocked = drm_gem_cma_free_object,
	.gem_vm_ops = &drm_gem_cma_vm_ops,
	.dumb_create = drm_gem_cma_dumb_create,
	.dumb_map_offset = drm_gem_cma_dumb_map_offset,
	.dumb_destroy = drm_gem_dumb_destroy,
	.fops = &sti_driver_fops,

	.get_vblank_counter = drm_vblank_no_hw_counter,
	.enable_vblank = sti_crtc_enable_vblank,
	.disable_vblank = sti_crtc_disable_vblank,

	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
	.gem_prime_export = drm_gem_prime_export,
	.gem_prime_import = drm_gem_prime_import,
	.gem_prime_get_sg_table = drm_gem_cma_prime_get_sg_table,
	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
	.gem_prime_vmap = drm_gem_cma_prime_vmap,
	.gem_prime_vunmap = drm_gem_cma_prime_vunmap,
	.gem_prime_mmap = drm_gem_cma_prime_mmap,

	.debugfs_init = sti_drm_dbg_init,
	.debugfs_cleanup = sti_drm_dbg_cleanup,

	.name = DRIVER_NAME,
	.desc = DRIVER_DESC,
	.date = DRIVER_DATE,
	.major = DRIVER_MAJOR,
	.minor = DRIVER_MINOR,
};

static int compare_of(struct device *dev, void *data)
{
	return dev->of_node == data;
}

static int sti_init(struct drm_device *ddev)
{
	struct sti_private *private;

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

	ddev->dev_private = (void *)private;
	dev_set_drvdata(ddev->dev, ddev);
	private->drm_dev = ddev;

	mutex_init(&private->commit.lock);
	INIT_WORK(&private->commit.work, sti_atomic_work);

	drm_mode_config_init(ddev);

	sti_mode_config_init(ddev);

	drm_kms_helper_poll_init(ddev);

	return 0;
}

static void sti_cleanup(struct drm_device *ddev)
{
	struct sti_private *private = ddev->dev_private;

	if (private->fbdev) {
		drm_fbdev_cma_fini(private->fbdev);
		private->fbdev = NULL;
	}

	drm_kms_helper_poll_fini(ddev);
	drm_vblank_cleanup(ddev);
	kfree(private);
	ddev->dev_private = NULL;
}

static int sti_bind(struct device *dev)
{
	struct drm_device *ddev;
	int ret;

	ddev = drm_dev_alloc(&sti_driver, dev);
	if (!ddev)
		return -ENOMEM;

	ddev->platformdev = to_platform_device(dev);

	ret = sti_init(ddev);
	if (ret)
		goto err_drm_dev_unref;

	ret = component_bind_all(ddev->dev, ddev);
	if (ret)
		goto err_cleanup;

	ret = drm_dev_register(ddev, 0);
	if (ret)
		goto err_register;

	drm_mode_config_reset(ddev);

	return 0;

err_register:
	drm_mode_config_cleanup(ddev);
err_cleanup:
	sti_cleanup(ddev);
err_drm_dev_unref:
	drm_dev_unref(ddev);
	return ret;
}

static void sti_unbind(struct device *dev)
{
	struct drm_device *ddev = dev_get_drvdata(dev);

	drm_dev_unregister(ddev);
	sti_cleanup(ddev);
	drm_dev_unref(ddev);
}

static const struct component_master_ops sti_ops = {
	.bind = sti_bind,
	.unbind = sti_unbind,
};

static int sti_platform_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *node = dev->of_node;
	struct device_node *child_np;
	struct component_match *match = NULL;

	dma_set_coherent_mask(dev, DMA_BIT_MASK(32));

	of_platform_populate(node, NULL, NULL, dev);

	child_np = of_get_next_available_child(node, NULL);

	while (child_np) {
		component_match_add(dev, &match, compare_of, child_np);
		of_node_put(child_np);
		child_np = of_get_next_available_child(node, child_np);
	}

	return component_master_add_with_match(dev, &sti_ops, match);
}

static int sti_platform_remove(struct platform_device *pdev)
{
	component_master_del(&pdev->dev, &sti_ops);
	of_platform_depopulate(&pdev->dev);

	return 0;
}

static const struct of_device_id sti_dt_ids[] = {
	{ .compatible = "st,sti-display-subsystem", },
	{ /* end node */ },
};
MODULE_DEVICE_TABLE(of, sti_dt_ids);

static struct platform_driver sti_platform_driver = {
	.probe = sti_platform_probe,
	.remove = sti_platform_remove,
	.driver = {
		.name = DRIVER_NAME,
		.of_match_table = sti_dt_ids,
	},
};

static struct platform_driver * const drivers[] = {
	&sti_tvout_driver,
	&sti_vtac_driver,
	&sti_hqvdp_driver,
	&sti_hdmi_driver,
	&sti_hda_driver,
	&sti_dvo_driver,
	&sti_vtg_driver,
	&sti_compositor_driver,
	&sti_platform_driver,
};

static int sti_drm_init(void)
{
	return platform_register_drivers(drivers, ARRAY_SIZE(drivers));
}
module_init(sti_drm_init);

static void sti_drm_exit(void)
{
	platform_unregister_drivers(drivers, ARRAY_SIZE(drivers));
}
module_exit(sti_drm_exit);

MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
MODULE_DESCRIPTION("STMicroelectronics SoC DRM driver");
MODULE_LICENSE("GPL");