// 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_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_framebuffer *fb = helper->fb;
        struct drm_gem_object *bo = msm_framebuffer_bo(fb, 0);

        DBG();

        drm_fb_helper_fini(helper);

        /* this will free the backing object */
        msm_gem_put_vaddr(bo);
        drm_framebuffer_remove(fb);

        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_device *dev = helper->dev;
        struct msm_drm_private *priv = dev->dev_private;
        struct fb_info *fbi = helper->info;
        struct drm_framebuffer *fb = NULL;
        struct drm_gem_object *bo;
        uint64_t paddr;
        uint32_t format;
        int ret, pitch;

        format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);

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

        pitch = align_pitch(sizes->surface_width, sizes->surface_bpp);
        fb = msm_alloc_stolen_fb(dev, sizes->surface_width,
                        sizes->surface_height, pitch, format);

        if (IS_ERR(fb)) {
                DRM_DEV_ERROR(dev->dev, "failed to allocate fb\n");
                return PTR_ERR(fb);
        }

        bo = msm_framebuffer_bo(fb, 0);

        /*
         * 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_DEV_ERROR(dev->dev, "failed to get buffer obj iova: %d\n", ret);
                goto fail;
        }

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

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

        fbi->fbops = &msm_fb_ops;

        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 fail;
        }
        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", fb->width, fb->height);

        return 0;

fail:
        drm_framebuffer_remove(fb);
        return ret;
}