/*
 * Copyright (C) 2012 Russell King
 *  Written from the i915 driver.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/errno.h>
#include <linux/fb.h>
#include <linux/kernel.h>
#include <linux/module.h>

#include <drm/drmP.h>
#include <drm/drm_fb_helper.h>
#include "armada_crtc.h"
#include "armada_drm.h"
#include "armada_fb.h"
#include "armada_gem.h"

static /*const*/ struct fb_ops armada_fb_ops = {
        .owner          = THIS_MODULE,
        .fb_check_var   = drm_fb_helper_check_var,
        .fb_set_par     = drm_fb_helper_set_par,
        .fb_fillrect    = drm_fb_helper_cfb_fillrect,
        .fb_copyarea    = drm_fb_helper_cfb_copyarea,
        .fb_imageblit   = drm_fb_helper_cfb_imageblit,
        .fb_pan_display = drm_fb_helper_pan_display,
        .fb_blank       = drm_fb_helper_blank,
        .fb_setcmap     = drm_fb_helper_setcmap,
        .fb_debug_enter = drm_fb_helper_debug_enter,
        .fb_debug_leave = drm_fb_helper_debug_leave,
};

static int armada_fb_create(struct drm_fb_helper *fbh,
        struct drm_fb_helper_surface_size *sizes)
{
        struct drm_device *dev = fbh->dev;
        struct drm_mode_fb_cmd2 mode;
        struct armada_framebuffer *dfb;
        struct armada_gem_object *obj;
        struct fb_info *info;
        int size, ret;
        void *ptr;

        memset(&mode, 0, sizeof(mode));
        mode.width = sizes->surface_width;
        mode.height = sizes->surface_height;
        mode.pitches[0] = armada_pitch(mode.width, sizes->surface_bpp);
        mode.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
                                        sizes->surface_depth);

        size = mode.pitches[0] * mode.height;
        obj = armada_gem_alloc_private_object(dev, size);
        if (!obj) {
                DRM_ERROR("failed to allocate fb memory\n");
                return -ENOMEM;
        }

        ret = armada_gem_linear_back(dev, obj);
        if (ret) {
                drm_gem_object_unreference_unlocked(&obj->obj);
                return ret;
        }

        ptr = armada_gem_map_object(dev, obj);
        if (!ptr) {
                drm_gem_object_unreference_unlocked(&obj->obj);
                return -ENOMEM;
        }

        dfb = armada_framebuffer_create(dev, &mode, obj);

        /*
         * A reference is now held by the framebuffer object if
         * successful, otherwise this drops the ref for the error path.
         */
        drm_gem_object_unreference_unlocked(&obj->obj);

        if (IS_ERR(dfb))
                return PTR_ERR(dfb);

        info = drm_fb_helper_alloc_fbi(fbh);
        if (IS_ERR(info)) {
                ret = PTR_ERR(info);
                goto err_fballoc;
        }

        strlcpy(info->fix.id, "armada-drmfb", sizeof(info->fix.id));
        info->par = fbh;
        info->flags = FBINFO_DEFAULT | FBINFO_CAN_FORCE_OUTPUT;
        info->fbops = &armada_fb_ops;
        info->fix.smem_start = obj->phys_addr;
        info->fix.smem_len = obj->obj.size;
        info->screen_size = obj->obj.size;
        info->screen_base = ptr;
        fbh->fb = &dfb->fb;

        drm_fb_helper_fill_fix(info, dfb->fb.pitches[0], dfb->fb.depth);
        drm_fb_helper_fill_var(info, fbh, sizes->fb_width, sizes->fb_height);

        DRM_DEBUG_KMS("allocated %dx%d %dbpp fb: 0x%08llx\n",
                dfb->fb.width, dfb->fb.height, dfb->fb.bits_per_pixel,
                (unsigned long long)obj->phys_addr);

        return 0;

 err_fballoc:
        dfb->fb.funcs->destroy(&dfb->fb);
        return ret;
}

static int armada_fb_probe(struct drm_fb_helper *fbh,
        struct drm_fb_helper_surface_size *sizes)
{
        int ret = 0;

        if (!fbh->fb) {
                ret = armada_fb_create(fbh, sizes);
                if (ret == 0)
                        ret = 1;
        }
        return ret;
}

static const struct drm_fb_helper_funcs armada_fb_helper_funcs = {
        .gamma_set      = armada_drm_crtc_gamma_set,
        .gamma_get      = armada_drm_crtc_gamma_get,
        .fb_probe       = armada_fb_probe,
};

int armada_fbdev_init(struct drm_device *dev)
{
        struct armada_private *priv = dev->dev_private;
        struct drm_fb_helper *fbh;
        int ret;

        fbh = devm_kzalloc(dev->dev, sizeof(*fbh), GFP_KERNEL);
        if (!fbh)
                return -ENOMEM;

        priv->fbdev = fbh;

        drm_fb_helper_prepare(dev, fbh, &armada_fb_helper_funcs);

        ret = drm_fb_helper_init(dev, fbh, 1, 1);
        if (ret) {
                DRM_ERROR("failed to initialize drm fb helper\n");
                goto err_fb_helper;
        }

        ret = drm_fb_helper_single_add_all_connectors(fbh);
        if (ret) {
                DRM_ERROR("failed to add fb connectors\n");
                goto err_fb_setup;
        }

        ret = drm_fb_helper_initial_config(fbh, 32);
        if (ret) {
                DRM_ERROR("failed to set initial config\n");
                goto err_fb_setup;
        }

        return 0;
 err_fb_setup:
        drm_fb_helper_release_fbi(fbh);
        drm_fb_helper_fini(fbh);
 err_fb_helper:
        priv->fbdev = NULL;
        return ret;
}

void armada_fbdev_lastclose(struct drm_device *dev)
{
        struct armada_private *priv = dev->dev_private;

        if (priv->fbdev)
                drm_fb_helper_restore_fbdev_mode_unlocked(priv->fbdev);
}

void armada_fbdev_fini(struct drm_device *dev)
{
        struct armada_private *priv = dev->dev_private;
        struct drm_fb_helper *fbh = priv->fbdev;

        if (fbh) {
                drm_fb_helper_unregister_fbi(fbh);
                drm_fb_helper_release_fbi(fbh);

                drm_fb_helper_fini(fbh);

                if (fbh->fb)
                        fbh->fb->funcs->destroy(fbh->fb);

                priv->fbdev = NULL;
        }
}