/*
 * Copyright (C) Fuzhou Rockchip Electronics Co.Ltd
 * Author:Mark Yao <mark.yao@rock-chips.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 */

#include <linux/kernel.h>
#include <drm/drm.h>
#include <drm/drmP.h>
#include <drm/drm_atomic.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_crtc_helper.h>

#include "rockchip_drm_drv.h"
#include "rockchip_drm_gem.h"

#define to_rockchip_fb(x) container_of(x, struct rockchip_drm_fb, fb)

struct rockchip_drm_fb {
        struct drm_framebuffer fb;
        struct drm_gem_object *obj[ROCKCHIP_MAX_FB_BUFFER];
};

struct drm_gem_object *rockchip_fb_get_gem_obj(struct drm_framebuffer *fb,
                                               unsigned int plane)
{
        struct rockchip_drm_fb *rk_fb = to_rockchip_fb(fb);

        if (plane >= ROCKCHIP_MAX_FB_BUFFER)
                return NULL;

        return rk_fb->obj[plane];
}

static void rockchip_drm_fb_destroy(struct drm_framebuffer *fb)
{
        struct rockchip_drm_fb *rockchip_fb = to_rockchip_fb(fb);
        struct drm_gem_object *obj;
        int i;

        for (i = 0; i < ROCKCHIP_MAX_FB_BUFFER; i++) {
                obj = rockchip_fb->obj[i];
                if (obj)
                        drm_gem_object_unreference_unlocked(obj);
        }

        drm_framebuffer_cleanup(fb);
        kfree(rockchip_fb);
}

static int rockchip_drm_fb_create_handle(struct drm_framebuffer *fb,
                                         struct drm_file *file_priv,
                                         unsigned int *handle)
{
        struct rockchip_drm_fb *rockchip_fb = to_rockchip_fb(fb);

        return drm_gem_handle_create(file_priv,
                                     rockchip_fb->obj[0], handle);
}

static const struct drm_framebuffer_funcs rockchip_drm_fb_funcs = {
        .destroy        = rockchip_drm_fb_destroy,
        .create_handle  = rockchip_drm_fb_create_handle,
};

static struct rockchip_drm_fb *
rockchip_fb_alloc(struct drm_device *dev, const struct drm_mode_fb_cmd2 *mode_cmd,
                  struct drm_gem_object **obj, unsigned int num_planes)
{
        struct rockchip_drm_fb *rockchip_fb;
        int ret;
        int i;

        rockchip_fb = kzalloc(sizeof(*rockchip_fb), GFP_KERNEL);
        if (!rockchip_fb)
                return ERR_PTR(-ENOMEM);

        drm_helper_mode_fill_fb_struct(&rockchip_fb->fb, mode_cmd);

        for (i = 0; i < num_planes; i++)
                rockchip_fb->obj[i] = obj[i];

        ret = drm_framebuffer_init(dev, &rockchip_fb->fb,
                                   &rockchip_drm_fb_funcs);
        if (ret) {
                dev_err(dev->dev, "Failed to initialize framebuffer: %d\n",
                        ret);
                kfree(rockchip_fb);
                return ERR_PTR(ret);
        }

        return rockchip_fb;
}

static struct drm_framebuffer *
rockchip_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
                        const struct drm_mode_fb_cmd2 *mode_cmd)
{
        struct rockchip_drm_fb *rockchip_fb;
        struct drm_gem_object *objs[ROCKCHIP_MAX_FB_BUFFER];
        struct drm_gem_object *obj;
        unsigned int hsub;
        unsigned int vsub;
        int num_planes;
        int ret;
        int i;

        hsub = drm_format_horz_chroma_subsampling(mode_cmd->pixel_format);
        vsub = drm_format_vert_chroma_subsampling(mode_cmd->pixel_format);
        num_planes = min(drm_format_num_planes(mode_cmd->pixel_format),
                         ROCKCHIP_MAX_FB_BUFFER);

        for (i = 0; i < num_planes; i++) {
                unsigned int width = mode_cmd->width / (i ? hsub : 1);
                unsigned int height = mode_cmd->height / (i ? vsub : 1);
                unsigned int min_size;

                obj = drm_gem_object_lookup(dev, file_priv,
                                            mode_cmd->handles[i]);
                if (!obj) {
                        dev_err(dev->dev, "Failed to lookup GEM object\n");
                        ret = -ENXIO;
                        goto err_gem_object_unreference;
                }

                min_size = (height - 1) * mode_cmd->pitches[i] +
                        mode_cmd->offsets[i] +
                        width * drm_format_plane_cpp(mode_cmd->pixel_format, i);

                if (obj->size < min_size) {
                        drm_gem_object_unreference_unlocked(obj);
                        ret = -EINVAL;
                        goto err_gem_object_unreference;
                }
                objs[i] = obj;
        }

        rockchip_fb = rockchip_fb_alloc(dev, mode_cmd, objs, i);
        if (IS_ERR(rockchip_fb)) {
                ret = PTR_ERR(rockchip_fb);
                goto err_gem_object_unreference;
        }

        return &rockchip_fb->fb;

err_gem_object_unreference:
        for (i--; i >= 0; i--)
                drm_gem_object_unreference_unlocked(objs[i]);
        return ERR_PTR(ret);
}

static void rockchip_drm_output_poll_changed(struct drm_device *dev)
{
        struct rockchip_drm_private *private = dev->dev_private;
        struct drm_fb_helper *fb_helper = &private->fbdev_helper;

        if (fb_helper)
                drm_fb_helper_hotplug_event(fb_helper);
}

static void rockchip_crtc_wait_for_update(struct drm_crtc *crtc)
{
        struct rockchip_drm_private *priv = crtc->dev->dev_private;
        int pipe = drm_crtc_index(crtc);
        const struct rockchip_crtc_funcs *crtc_funcs = priv->crtc_funcs[pipe];

        if (crtc_funcs && crtc_funcs->wait_for_update)
                crtc_funcs->wait_for_update(crtc);
}

/*
 * We can't use drm_atomic_helper_wait_for_vblanks() because rk3288 and rk3066
 * have hardware counters for neither vblanks nor scanlines, which results in
 * a race where:
 *                              | <-- HW vsync irq and reg take effect
 *             plane_commit --> |
 *      get_vblank and wait --> |
 *                              | <-- handle_vblank, vblank->count + 1
 *               cleanup_fb --> |
 *              iommu crash --> |
 *                              | <-- HW vsync irq and reg take effect
 *
 * This function is equivalent but uses rockchip_crtc_wait_for_update() instead
 * of waiting for vblank_count to change.
 */
static void
rockchip_atomic_wait_for_complete(struct drm_device *dev, struct drm_atomic_state *old_state)
{
        struct drm_crtc_state *old_crtc_state;
        struct drm_crtc *crtc;
        int i, ret;

        for_each_crtc_in_state(old_state, crtc, old_crtc_state, i) {
                /* No one cares about the old state, so abuse it for tracking
                 * and store whether we hold a vblank reference (and should do a
                 * vblank wait) in the ->enable boolean.
                 */
                old_crtc_state->enable = false;

                if (!crtc->state->active)
                        continue;

                if (!drm_atomic_helper_framebuffer_changed(dev,
                                old_state, crtc))
                        continue;

                ret = drm_crtc_vblank_get(crtc);
                if (ret != 0)
                        continue;

                old_crtc_state->enable = true;
        }

        for_each_crtc_in_state(old_state, crtc, old_crtc_state, i) {
                if (!old_crtc_state->enable)
                        continue;

                rockchip_crtc_wait_for_update(crtc);
                drm_crtc_vblank_put(crtc);
        }
}

static void
rockchip_atomic_commit_complete(struct rockchip_atomic_commit *commit)
{
        struct drm_atomic_state *state = commit->state;
        struct drm_device *dev = commit->dev;

        /*
         * TODO: do fence wait here.
         */

        /*
         * Rockchip crtc support runtime PM, can't update display planes
         * when crtc is disabled.
         *
         * drm_atomic_helper_commit comments detail that:
         *     For drivers supporting runtime PM the recommended sequence is
         *
         *     drm_atomic_helper_commit_modeset_disables(dev, state);
         *
         *     drm_atomic_helper_commit_modeset_enables(dev, state);
         *
         *     drm_atomic_helper_commit_planes(dev, state, true);
         *
         * See the kerneldoc entries for these three functions for more details.
         */
        drm_atomic_helper_commit_modeset_disables(dev, state);

        drm_atomic_helper_commit_modeset_enables(dev, state);

        drm_atomic_helper_commit_planes(dev, state, true);

        rockchip_atomic_wait_for_complete(dev, state);

        drm_atomic_helper_cleanup_planes(dev, state);

        drm_atomic_state_free(state);
}

void rockchip_drm_atomic_work(struct work_struct *work)
{
        struct rockchip_atomic_commit *commit = container_of(work,
                                        struct rockchip_atomic_commit, work);

        rockchip_atomic_commit_complete(commit);
}

int rockchip_drm_atomic_commit(struct drm_device *dev,
                               struct drm_atomic_state *state,
                               bool async)
{
        struct rockchip_drm_private *private = dev->dev_private;
        struct rockchip_atomic_commit *commit = &private->commit;
        int ret;

        ret = drm_atomic_helper_prepare_planes(dev, state);
        if (ret)
                return ret;

        /* serialize outstanding asynchronous commits */
        mutex_lock(&commit->lock);
        flush_work(&commit->work);

        drm_atomic_helper_swap_state(dev, state);

        commit->dev = dev;
        commit->state = state;

        if (async)
                schedule_work(&commit->work);
        else
                rockchip_atomic_commit_complete(commit);

        mutex_unlock(&commit->lock);

        return 0;
}

static const struct drm_mode_config_funcs rockchip_drm_mode_config_funcs = {
        .fb_create = rockchip_user_fb_create,
        .output_poll_changed = rockchip_drm_output_poll_changed,
        .atomic_check = drm_atomic_helper_check,
        .atomic_commit = rockchip_drm_atomic_commit,
};

struct drm_framebuffer *
rockchip_drm_framebuffer_init(struct drm_device *dev,
                              const struct drm_mode_fb_cmd2 *mode_cmd,
                              struct drm_gem_object *obj)
{
        struct rockchip_drm_fb *rockchip_fb;

        rockchip_fb = rockchip_fb_alloc(dev, mode_cmd, &obj, 1);
        if (IS_ERR(rockchip_fb))
                return NULL;

        return &rockchip_fb->fb;
}

void rockchip_drm_mode_config_init(struct drm_device *dev)
{
        dev->mode_config.min_width = 0;
        dev->mode_config.min_height = 0;

        /*
         * set max width and height as default value(4096x4096).
         * this value would be used to check framebuffer size limitation
         * at drm_mode_addfb().
         */
        dev->mode_config.max_width = 4096;
        dev->mode_config.max_height = 4096;

        dev->mode_config.funcs = &rockchip_drm_mode_config_funcs;
}