/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <drm/drm_crtc.h>
#include <drm/drm_fb_helper.h>

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

extern int msm_gem_mmap_obj(struct drm_gem_object *obj,
                                        struct vm_area_struct *vma);
static int msm_fbdev_mmap(struct fb_info *info, struct vm_area_struct *vma);

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

#define to_msm_fbdev(x) container_of(x, struct msm_fbdev, base)

struct msm_fbdev {
        struct drm_fb_helper base;
        struct drm_framebuffer *fb;
        struct drm_gem_object *bo;
};

static struct fb_ops msm_fb_ops = {
        .owner = THIS_MODULE,
        DRM_FB_HELPER_DEFAULT_OPS,

        /* Note: to properly handle manual update displays, we wrap the
         * basic fbdev ops which write to the framebuffer
         */
        .fb_read = drm_fb_helper_sys_read,
        .fb_write = drm_fb_helper_sys_write,
        .fb_fillrect = drm_fb_helper_sys_fillrect,
        .fb_copyarea = drm_fb_helper_sys_copyarea,
        .fb_imageblit = drm_fb_helper_sys_imageblit,
        .fb_mmap = msm_fbdev_mmap,
};

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 msm_fbdev *fbdev = to_msm_fbdev(helper);
        struct drm_gem_object *drm_obj = fbdev->bo;
        int ret = 0;

        ret = drm_gem_mmap_obj(drm_obj, drm_obj->size, vma);
        if (ret) {
                pr_err("%s:drm_gem_mmap_obj fail\n", __func__);
                return ret;
        }

        return msm_gem_mmap_obj(drm_obj, vma);
}

static int msm_fbdev_create(struct drm_fb_helper *helper,
                struct drm_fb_helper_surface_size *sizes)
{
        struct msm_fbdev *fbdev = to_msm_fbdev(helper);
        struct drm_device *dev = helper->dev;
        struct msm_drm_private *priv = dev->dev_private;
        struct drm_framebuffer *fb = NULL;
        struct fb_info *fbi = NULL;
        struct drm_mode_fb_cmd2 mode_cmd = {0};
        uint64_t paddr;
        int ret, size;

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

        mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
                        sizes->surface_depth);

        mode_cmd.width = sizes->surface_width;
        mode_cmd.height = sizes->surface_height;

        mode_cmd.pitches[0] = align_pitch(
                        mode_cmd.width, sizes->surface_bpp);

        /* allocate backing bo */
        size = mode_cmd.pitches[0] * mode_cmd.height;
        DBG("allocating %d bytes for fb %d", size, dev->primary->index);
        fbdev->bo = msm_gem_new(dev, size, MSM_BO_SCANOUT |
                        MSM_BO_WC | MSM_BO_STOLEN);
        if (IS_ERR(fbdev->bo)) {
                ret = PTR_ERR(fbdev->bo);
                fbdev->bo = NULL;
                dev_err(dev->dev, "failed to allocate buffer object: %d\n", ret);
                goto fail;
        }

        fb = msm_framebuffer_init(dev, &mode_cmd, &fbdev->bo);
        if (IS_ERR(fb)) {
                dev_err(dev->dev, "failed to allocate fb\n");
                /* note: if fb creation failed, we can't rely on fb destroy
                 * to unref the bo:
                 */
                drm_gem_object_unreference_unlocked(fbdev->bo);
                ret = PTR_ERR(fb);
                goto fail;
        }

        mutex_lock(&dev->struct_mutex);

        /*
         * 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_iova(fbdev->bo, priv->kms->aspace, &paddr);
        if (ret) {
                dev_err(dev->dev, "failed to get buffer obj iova: %d\n", ret);
                goto fail_unlock;
        }

        fbi = drm_fb_helper_alloc_fbi(helper);
        if (IS_ERR(fbi)) {
                dev_err(dev->dev, "failed to allocate fb info\n");
                ret = PTR_ERR(fbi);
                goto fail_unlock;
        }

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

        fbdev->fb = fb;
        helper->fb = fb;

        fbi->par = helper;
        fbi->flags = FBINFO_DEFAULT;
        fbi->fbops = &msm_fb_ops;

        strcpy(fbi->fix.id, "msm");

        drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->format->depth);
        drm_fb_helper_fill_var(fbi, helper, sizes->fb_width, sizes->fb_height);

        dev->mode_config.fb_base = paddr;

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

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

        mutex_unlock(&dev->struct_mutex);

        return 0;

fail_unlock:
        mutex_unlock(&dev->struct_mutex);
fail:

        if (ret) {
                if (fb)
                        drm_framebuffer_remove(fb);
        }

        return ret;
}

static const struct drm_fb_helper_funcs msm_fb_helper_funcs = {
        .fb_probe = msm_fbdev_create,
};

/* initialize fbdev helper */
struct drm_fb_helper *msm_fbdev_init(struct drm_device *dev)
{
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_fbdev *fbdev = NULL;
        struct drm_fb_helper *helper;
        int ret;

        fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
        if (!fbdev)
                goto fail;

        helper = &fbdev->base;

        drm_fb_helper_prepare(dev, helper, &msm_fb_helper_funcs);

        ret = drm_fb_helper_init(dev, helper, priv->num_connectors);
        if (ret) {
                dev_err(dev->dev, "could not init fbdev: ret=%d\n", ret);
                goto fail;
        }

        ret = drm_fb_helper_single_add_all_connectors(helper);
        if (ret)
                goto fini;

        ret = drm_fb_helper_initial_config(helper, 32);
        if (ret)
                goto fini;

        priv->fbdev = helper;

        return helper;

fini:
        drm_fb_helper_fini(helper);
fail:
        kfree(fbdev);
        return NULL;
}

void msm_fbdev_free(struct drm_device *dev)
{
        struct msm_drm_private *priv = dev->dev_private;
        struct drm_fb_helper *helper = priv->fbdev;
        struct msm_fbdev *fbdev;

        DBG();

        drm_fb_helper_unregister_fbi(helper);

        drm_fb_helper_fini(helper);

        fbdev = to_msm_fbdev(priv->fbdev);

        /* this will free the backing object */
        if (fbdev->fb) {
                msm_gem_put_vaddr(fbdev->bo);
                drm_framebuffer_remove(fbdev->fb);
        }

        kfree(fbdev);

        priv->fbdev = NULL;
}