// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2010 Matt Turner.
 * Copyright 2012 Red Hat
 *
 * Authors: Matthew Garrett
 *          Matt Turner
 *          Dave Airlie
 */
#include <linux/module.h>
#include <drm/drmP.h>
#include <drm/drm_util.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_crtc_helper.h>

#include "mgag200_drv.h"

static void mga_dirty_update(struct mga_fbdev *mfbdev,
			     int x, int y, int width, int height)
{
	int i;
	struct drm_gem_object *obj;
	struct drm_gem_vram_object *gbo;
	int src_offset, dst_offset;
	int bpp = mfbdev->mfb.base.format->cpp[0];
	int ret;
	u8 *dst;
	bool unmap = false;
	bool store_for_later = false;
	int x2, y2;
	unsigned long flags;

	obj = mfbdev->mfb.obj;
	gbo = drm_gem_vram_of_gem(obj);

	if (drm_can_sleep()) {
		/* We pin the BO so it won't be moved during the
		 * update. The actual location, video RAM or system
		 * memory, is not important.
		 */
		ret = drm_gem_vram_pin(gbo, 0);
		if (ret) {
			if (ret != -EBUSY)
				return;
			store_for_later = true;
		}
	} else {
		store_for_later = true;
	}

	x2 = x + width - 1;
	y2 = y + height - 1;
	spin_lock_irqsave(&mfbdev->dirty_lock, flags);

	if (mfbdev->y1 < y)
		y = mfbdev->y1;
	if (mfbdev->y2 > y2)
		y2 = mfbdev->y2;
	if (mfbdev->x1 < x)
		x = mfbdev->x1;
	if (mfbdev->x2 > x2)
		x2 = mfbdev->x2;

	if (store_for_later) {
		mfbdev->x1 = x;
		mfbdev->x2 = x2;
		mfbdev->y1 = y;
		mfbdev->y2 = y2;
		spin_unlock_irqrestore(&mfbdev->dirty_lock, flags);
		return;
	}

	mfbdev->x1 = mfbdev->y1 = INT_MAX;
	mfbdev->x2 = mfbdev->y2 = 0;
	spin_unlock_irqrestore(&mfbdev->dirty_lock, flags);

	dst = drm_gem_vram_kmap(gbo, false, NULL);
	if (IS_ERR(dst)) {
		DRM_ERROR("failed to kmap fb updates\n");
		goto out;
	} else if (!dst) {
		dst = drm_gem_vram_kmap(gbo, true, NULL);
		if (IS_ERR(dst)) {
			DRM_ERROR("failed to kmap fb updates\n");
			goto out;
		}
		unmap = true;
	}

	for (i = y; i <= y2; i++) {
		/* assume equal stride for now */
		src_offset = dst_offset =
			i * mfbdev->mfb.base.pitches[0] + (x * bpp);
		memcpy_toio(dst + dst_offset, mfbdev->sysram + src_offset,
			    (x2 - x + 1) * bpp);
	}

	if (unmap)
		drm_gem_vram_kunmap(gbo);

out:
	drm_gem_vram_unpin(gbo);
}

static void mga_fillrect(struct fb_info *info,
			 const struct fb_fillrect *rect)
{
	struct mga_fbdev *mfbdev = info->par;
	drm_fb_helper_sys_fillrect(info, rect);
	mga_dirty_update(mfbdev, rect->dx, rect->dy, rect->width,
			 rect->height);
}

static void mga_copyarea(struct fb_info *info,
			 const struct fb_copyarea *area)
{
	struct mga_fbdev *mfbdev = info->par;
	drm_fb_helper_sys_copyarea(info, area);
	mga_dirty_update(mfbdev, area->dx, area->dy, area->width,
			 area->height);
}

static void mga_imageblit(struct fb_info *info,
			  const struct fb_image *image)
{
	struct mga_fbdev *mfbdev = info->par;
	drm_fb_helper_sys_imageblit(info, image);
	mga_dirty_update(mfbdev, image->dx, image->dy, image->width,
			 image->height);
}


static struct fb_ops mgag200fb_ops = {
	.owner = THIS_MODULE,
	.fb_check_var = drm_fb_helper_check_var,
	.fb_set_par = drm_fb_helper_set_par,
	.fb_fillrect = mga_fillrect,
	.fb_copyarea = mga_copyarea,
	.fb_imageblit = mga_imageblit,
	.fb_pan_display = drm_fb_helper_pan_display,
	.fb_blank = drm_fb_helper_blank,
	.fb_setcmap = drm_fb_helper_setcmap,
};

static int mgag200fb_create_object(struct mga_fbdev *afbdev,
				   const struct drm_mode_fb_cmd2 *mode_cmd,
				   struct drm_gem_object **gobj_p)
{
	struct drm_device *dev = afbdev->helper.dev;
	u32 size;
	struct drm_gem_object *gobj;
	int ret = 0;

	size = mode_cmd->pitches[0] * mode_cmd->height;
	ret = mgag200_gem_create(dev, size, true, &gobj);
	if (ret)
		return ret;

	*gobj_p = gobj;
	return ret;
}

static int mgag200fb_create(struct drm_fb_helper *helper,
			   struct drm_fb_helper_surface_size *sizes)
{
	struct mga_fbdev *mfbdev =
		container_of(helper, struct mga_fbdev, helper);
	struct drm_device *dev = mfbdev->helper.dev;
	struct drm_mode_fb_cmd2 mode_cmd;
	struct mga_device *mdev = dev->dev_private;
	struct fb_info *info;
	struct drm_framebuffer *fb;
	struct drm_gem_object *gobj = NULL;
	int ret;
	void *sysram;
	int size;

	mode_cmd.width = sizes->surface_width;
	mode_cmd.height = sizes->surface_height;
	mode_cmd.pitches[0] = mode_cmd.width * ((sizes->surface_bpp + 7) / 8);

	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
							  sizes->surface_depth);
	size = mode_cmd.pitches[0] * mode_cmd.height;

	ret = mgag200fb_create_object(mfbdev, &mode_cmd, &gobj);
	if (ret) {
		DRM_ERROR("failed to create fbcon backing object %d\n", ret);
		return ret;
	}

	sysram = vmalloc(size);
	if (!sysram) {
		ret = -ENOMEM;
		goto err_sysram;
	}

	info = drm_fb_helper_alloc_fbi(helper);
	if (IS_ERR(info)) {
		ret = PTR_ERR(info);
		goto err_alloc_fbi;
	}

	ret = mgag200_framebuffer_init(dev, &mfbdev->mfb, &mode_cmd, gobj);
	if (ret)
		goto err_alloc_fbi;

	mfbdev->sysram = sysram;
	mfbdev->size = size;

	fb = &mfbdev->mfb.base;

	/* setup helper */
	mfbdev->helper.fb = fb;

	info->fbops = &mgag200fb_ops;

	/* setup aperture base/size for vesafb takeover */
	info->apertures->ranges[0].base = mdev->dev->mode_config.fb_base;
	info->apertures->ranges[0].size = mdev->mc.vram_size;

	drm_fb_helper_fill_info(info, &mfbdev->helper, sizes);

	info->screen_base = sysram;
	info->screen_size = size;
	info->pixmap.flags = FB_PIXMAP_SYSTEM;

	DRM_DEBUG_KMS("allocated %dx%d\n",
		      fb->width, fb->height);

	return 0;

err_alloc_fbi:
	vfree(sysram);
err_sysram:
	drm_gem_object_put_unlocked(gobj);

	return ret;
}

static int mga_fbdev_destroy(struct drm_device *dev,
				struct mga_fbdev *mfbdev)
{
	struct mga_framebuffer *mfb = &mfbdev->mfb;

	drm_fb_helper_unregister_fbi(&mfbdev->helper);

	if (mfb->obj) {
		drm_gem_object_put_unlocked(mfb->obj);
		mfb->obj = NULL;
	}
	drm_fb_helper_fini(&mfbdev->helper);
	vfree(mfbdev->sysram);
	drm_framebuffer_unregister_private(&mfb->base);
	drm_framebuffer_cleanup(&mfb->base);

	return 0;
}

static const struct drm_fb_helper_funcs mga_fb_helper_funcs = {
	.fb_probe = mgag200fb_create,
};

int mgag200_fbdev_init(struct mga_device *mdev)
{
	struct mga_fbdev *mfbdev;
	int ret;
	int bpp_sel = 32;

	/* prefer 16bpp on low end gpus with limited VRAM */
	if (IS_G200_SE(mdev) && mdev->mc.vram_size < (2048*1024))
		bpp_sel = 16;

	mfbdev = devm_kzalloc(mdev->dev->dev, sizeof(struct mga_fbdev), GFP_KERNEL);
	if (!mfbdev)
		return -ENOMEM;

	mdev->mfbdev = mfbdev;
	spin_lock_init(&mfbdev->dirty_lock);

	drm_fb_helper_prepare(mdev->dev, &mfbdev->helper, &mga_fb_helper_funcs);

	ret = drm_fb_helper_init(mdev->dev, &mfbdev->helper,
				 MGAG200FB_CONN_LIMIT);
	if (ret)
		goto err_fb_helper;

	ret = drm_fb_helper_single_add_all_connectors(&mfbdev->helper);
	if (ret)
		goto err_fb_setup;

	/* disable all the possible outputs/crtcs before entering KMS mode */
	drm_helper_disable_unused_functions(mdev->dev);

	ret = drm_fb_helper_initial_config(&mfbdev->helper, bpp_sel);
	if (ret)
		goto err_fb_setup;

	return 0;

err_fb_setup:
	drm_fb_helper_fini(&mfbdev->helper);
err_fb_helper:
	mdev->mfbdev = NULL;

	return ret;
}

void mgag200_fbdev_fini(struct mga_device *mdev)
{
	if (!mdev->mfbdev)
		return;

	mga_fbdev_destroy(mdev->dev, mdev->mfbdev);
}