/*
 * Copyright 2010 Matt Turner.
 * Copyright 2012 Red Hat
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License version 2. See the file COPYING in the main
 * directory of this archive for more details.
 *
 * Authors: Matthew Garrett
 *          Matt Turner
 *          Dave Airlie
 */
#include <linux/module.h>
#include <drm/drmP.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 mgag200_bo *bo;
        int src_offset, dst_offset;
        int bpp = mfbdev->mfb.base.format->cpp[0];
        int ret = -EBUSY;
        bool unmap = false;
        bool store_for_later = false;
        int x2, y2;
        unsigned long flags;

        obj = mfbdev->mfb.obj;
        bo = gem_to_mga_bo(obj);

        /*
         * try and reserve the BO, if we fail with busy
         * then the BO is being moved and we should
         * store up the damage until later.
         */
        if (drm_can_sleep())
                ret = mgag200_bo_reserve(bo, true);
        if (ret) {
                if (ret != -EBUSY)
                        return;

                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);

        if (!bo->kmap.virtual) {
                ret = ttm_bo_kmap(&bo->bo, 0, bo->bo.num_pages, &bo->kmap);
                if (ret) {
                        DRM_ERROR("failed to kmap fb updates\n");
                        mgag200_bo_unreserve(bo);
                        return;
                }
                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(bo->kmap.virtual + src_offset, mfbdev->sysram + src_offset, (x2 - x + 1) * bpp);

        }
        if (unmap)
                ttm_bo_kunmap(&bo->kmap);

        mgag200_bo_unreserve(bo);
}

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;
        }

        info->par = mfbdev;

        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;

        strcpy(info->fix.id, "mgadrmfb");

        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_fix(info, fb->pitches[0], fb->format->depth);
        drm_fb_helper_fill_var(info, &mfbdev->helper, sizes->fb_width,
                               sizes->fb_height);

        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);
}