// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 */

#include <linux/fb.h>

#include <drm/drm_drv.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_file.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_prime.h>

#include "msm_drv.h"
#include "msm_gem.h"
#include "msm_kms.h"

static bool fbdev = true;
MODULE_PARM_DESC(fbdev, "Enable fbdev compat layer");
module_param(fbdev, bool, 0600);

/*
 * fbdev funcs, to implement legacy fbdev interface on top of drm driver
 */

FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(msm_fbdev,
				   drm_fb_helper_damage_range,
				   drm_fb_helper_damage_area)

static int msm_fbdev_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
	struct drm_fb_helper *helper = (struct drm_fb_helper *)info->par;
	struct drm_gem_object *bo = msm_framebuffer_bo(helper->fb, 0);

	return drm_gem_prime_mmap(bo, vma);
}

static void msm_fbdev_fb_destroy(struct fb_info *info)
{
	struct drm_fb_helper *helper = (struct drm_fb_helper *)info->par;
	struct drm_gem_object *bo = msm_framebuffer_bo(helper->fb, 0);

	DBG();

	drm_fb_helper_fini(helper);

	msm_gem_put_vaddr(bo);

	drm_client_buffer_delete(helper->buffer);
	drm_client_release(&helper->client);
}

static const struct fb_ops msm_fb_ops = {
	.owner = THIS_MODULE,
	__FB_DEFAULT_DEFERRED_OPS_RDWR(msm_fbdev),
	DRM_FB_HELPER_DEFAULT_OPS,
	__FB_DEFAULT_DEFERRED_OPS_DRAW(msm_fbdev),
	.fb_mmap = msm_fbdev_mmap,
	.fb_destroy = msm_fbdev_fb_destroy,
};

static int msm_fbdev_fb_dirty(struct drm_fb_helper *helper,
			      struct drm_clip_rect *clip)
{
	struct drm_device *dev = helper->dev;
	int ret;

	/* Call damage handlers only if necessary */
	if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
		return 0;

	if (helper->fb->funcs->dirty) {
		ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
		if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
			return ret;
	}

	return 0;
}

static const struct drm_fb_helper_funcs msm_fbdev_helper_funcs = {
	.fb_dirty = msm_fbdev_fb_dirty,
};

int msm_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
				 struct drm_fb_helper_surface_size *sizes)
{
	struct drm_client_dev *client = &helper->client;
	struct drm_device *dev = client->dev;
	struct drm_file *file = client->file;
	struct msm_drm_private *priv = dev->dev_private;
	struct fb_info *fbi = helper->info;
	const struct drm_format_info *format;
	u32 fourcc, pitch, handle;
	u64 size;
	struct drm_gem_object *bo;
	struct drm_client_buffer *buffer;
	uint64_t paddr;
	int ret;

	DBG("create fbdev: %dx%d@%d (%dx%d)", sizes->surface_width,
			sizes->surface_height, sizes->surface_bpp,
			sizes->fb_width, sizes->fb_height);

	fourcc = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
	format = drm_get_format_info(dev, fourcc, DRM_FORMAT_MOD_LINEAR);
	/* adreno needs pitch aligned to 32 pixels: */
	pitch = drm_format_info_min_pitch(format, 0, ALIGN(sizes->surface_width, 32));
	size = ALIGN(pitch * sizes->surface_height, PAGE_SIZE);

	/* allocate backing bo */
	DBG("allocating %llu bytes for fb %d", size, dev->primary->index);
	bo = msm_gem_new(dev, size, MSM_BO_SCANOUT | MSM_BO_WC | MSM_BO_STOLEN, NULL);
	if (IS_ERR(bo)) {
		drm_warn(dev, "could not allocate stolen bo\n");
		/* try regular bo: */
		bo = msm_gem_new(dev, size, MSM_BO_SCANOUT | MSM_BO_WC, NULL);
		if (IS_ERR(bo)) {
			drm_err(dev, "failed to allocate buffer object\n");
			return PTR_ERR(bo);
		}
	}

	msm_gem_object_set_name(bo, "stolenfb");

	ret = drm_gem_handle_create(file, bo, &handle);
	if (ret)
		goto err_drm_gem_object_put;

	buffer = drm_client_buffer_create(client, sizes->surface_width, sizes->surface_height,
					  fourcc, handle, pitch);
	if (IS_ERR(buffer)) {
		ret = PTR_ERR(buffer);
		goto err_drm_gem_handle_delete;
	}

	/*
	 * NOTE: if we can be guaranteed to be able to map buffer
	 * in panic (ie. lock-safe, etc) we could avoid pinning the
	 * buffer now:
	 */
	ret = msm_gem_get_and_pin_iova(bo, priv->kms->vm, &paddr);
	if (ret) {
		drm_err(dev, "failed to get buffer obj iova: %d\n", ret);
		goto err_drm_client_buffer_delete;
	}

	DBG("fbi=%p, dev=%p", fbi, dev);

	helper->funcs = &msm_fbdev_helper_funcs;
	helper->buffer = buffer;
	helper->fb = buffer->fb;

	fbi->fbops = &msm_fb_ops;
	fbi->flags |= FBINFO_VIRTFB; /* system memory */

	drm_fb_helper_fill_info(fbi, helper, sizes);

	fbi->screen_buffer = msm_gem_get_vaddr(bo);
	if (IS_ERR(fbi->screen_buffer)) {
		ret = PTR_ERR(fbi->screen_buffer);
		goto err_msm_gem_unpin;
	}
	fbi->screen_size = bo->size;
	fbi->fix.smem_start = paddr;
	fbi->fix.smem_len = bo->size;

	DBG("par=%p, %dx%d", fbi->par, fbi->var.xres, fbi->var.yres);
	DBG("allocated %dx%d fb", buffer->fb->width, buffer->fb->height);

	/* The handle is only needed for creating the framebuffer. */
	drm_gem_handle_delete(file, handle);

	/* The framebuffer still holds a reference on the GEM object. */
	drm_gem_object_put(bo);

	return 0;

err_msm_gem_unpin:
	msm_gem_unpin_iova(bo, priv->kms->vm);
	msm_gem_vma_put(bo);
err_drm_client_buffer_delete:
	drm_client_buffer_delete(buffer);
err_drm_gem_handle_delete:
	drm_gem_handle_delete(file, handle);
err_drm_gem_object_put:
	drm_gem_object_put(bo);
	return ret;
}