/*
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <unistd.h>
 
 #include <drm.h>
 #include <xf86drm.h>
 
 #include "avassert.h"
 #include "hwcontext.h"
 #include "hwcontext_drm.h"
 #include "hwcontext_internal.h"
 #include "imgutils.h"
 
 
 static void drm_device_free(AVHWDeviceContext *hwdev)
 {
     AVDRMDeviceContext *hwctx = hwdev->hwctx;
 
     close(hwctx->fd);
 }
 
 static int drm_device_create(AVHWDeviceContext *hwdev, const char *device,
                              AVDictionary *opts, int flags)
 {
     AVDRMDeviceContext *hwctx = hwdev->hwctx;
     drmVersionPtr version;
 
     hwctx->fd = open(device, O_RDWR);
     if (hwctx->fd < 0)
         return AVERROR(errno);
 
     version = drmGetVersion(hwctx->fd);
     if (!version) {
         av_log(hwdev, AV_LOG_ERROR, "Failed to get version information "
                "from %s: probably not a DRM device?\n", device);
         close(hwctx->fd);
         return AVERROR(EINVAL);
     }
 
     av_log(hwdev, AV_LOG_VERBOSE, "Opened DRM device %s: driver %s "
            "version %d.%d.%d.\n", device, version->name,
            version->version_major, version->version_minor,
            version->version_patchlevel);
 
     drmFreeVersion(version);
 
     hwdev->free = &drm_device_free;
 
     return 0;
 }
 
 static int drm_get_buffer(AVHWFramesContext *hwfc, AVFrame *frame)
 {
     frame->buf[0] = av_buffer_pool_get(hwfc->pool);
     if (!frame->buf[0])
         return AVERROR(ENOMEM);
 
     frame->data[0] = (uint8_t*)frame->buf[0]->data;
 
     frame->format = AV_PIX_FMT_DRM_PRIME;
     frame->width  = hwfc->width;
     frame->height = hwfc->height;
 
     return 0;
 }
 
 typedef struct DRMMapping {
     // Address and length of each mmap()ed region.
     int nb_regions;
     void *address[AV_DRM_MAX_PLANES];
     size_t length[AV_DRM_MAX_PLANES];
 } DRMMapping;
 
 static void drm_unmap_frame(AVHWFramesContext *hwfc,
                             HWMapDescriptor *hwmap)
 {
     DRMMapping *map = hwmap->priv;
     int i;
 
     for (i = 0; i < map->nb_regions; i++)
         munmap(map->address[i], map->length[i]);
 
     av_free(map);
 }
 
 static int drm_map_frame(AVHWFramesContext *hwfc,
                          AVFrame *dst, const AVFrame *src, int flags)
 {
     const AVDRMFrameDescriptor *desc = (AVDRMFrameDescriptor*)src->data[0];
     DRMMapping *map;
     int err, i, p, plane;
     int mmap_prot;
     void *addr;
 
     map = av_mallocz(sizeof(*map));
     if (!map)
         return AVERROR(ENOMEM);
 
     mmap_prot = 0;
     if (flags & AV_HWFRAME_MAP_READ)
         mmap_prot |= PROT_READ;
     if (flags & AV_HWFRAME_MAP_WRITE)
         mmap_prot |= PROT_WRITE;
 
     av_assert0(desc->nb_objects <= AV_DRM_MAX_PLANES);
     for (i = 0; i < desc->nb_objects; i++) {
         addr = mmap(NULL, desc->objects[i].size, mmap_prot, MAP_SHARED,
                     desc->objects[i].fd, 0);
         if (addr == MAP_FAILED) {
             err = AVERROR(errno);
             av_log(hwfc, AV_LOG_ERROR, "Failed to map DRM object %d to "
                    "memory: %d.\n", desc->objects[i].fd, errno);
             goto fail;
         }
 
         map->address[i] = addr;
         map->length[i]  = desc->objects[i].size;
     }
     map->nb_regions = i;
 
     plane = 0;
     for (i = 0; i < desc->nb_layers; i++) {
         const AVDRMLayerDescriptor *layer = &desc->layers[i];
         for (p = 0; p < layer->nb_planes; p++) {
             dst->data[plane] =
                 (uint8_t*)map->address[layer->planes[p].object_index] +
                                        layer->planes[p].offset;
             dst->linesize[plane] =     layer->planes[p].pitch;
             ++plane;
         }
     }
     av_assert0(plane <= AV_DRM_MAX_PLANES);
 
     dst->width  = src->width;
     dst->height = src->height;
 
     err = ff_hwframe_map_create(src->hw_frames_ctx, dst, src,
                                 &drm_unmap_frame, map);
     if (err < 0)
         goto fail;
 
     return 0;
 
 fail:
     for (i = 0; i < desc->nb_objects; i++) {
         if (map->address[i])
             munmap(map->address[i], map->length[i]);
     }
     av_free(map);
     return err;
 }
 
 static int drm_transfer_get_formats(AVHWFramesContext *ctx,
                                     enum AVHWFrameTransferDirection dir,
                                     enum AVPixelFormat **formats)
 {
     enum AVPixelFormat *pix_fmts;
 
     pix_fmts = av_malloc_array(2, sizeof(*pix_fmts));
     if (!pix_fmts)
         return AVERROR(ENOMEM);
 
     pix_fmts[0] = ctx->sw_format;
     pix_fmts[1] = AV_PIX_FMT_NONE;
 
     *formats = pix_fmts;
     return 0;
 }
 
 static int drm_transfer_data_from(AVHWFramesContext *hwfc,
                                   AVFrame *dst, const AVFrame *src)
 {
     AVFrame *map;
     int err;
 
     if (dst->width > hwfc->width || dst->height > hwfc->height)
         return AVERROR(EINVAL);
 
     map = av_frame_alloc();
     if (!map)
         return AVERROR(ENOMEM);
     map->format = dst->format;
 
     err = drm_map_frame(hwfc, map, src, AV_HWFRAME_MAP_READ);
     if (err)
         goto fail;
 
     map->width  = dst->width;
     map->height = dst->height;
 
     err = av_frame_copy(dst, map);
     if (err)
         goto fail;
 
     err = 0;
 fail:
     av_frame_free(&map);
     return err;
 }
 
 static int drm_transfer_data_to(AVHWFramesContext *hwfc,
                                 AVFrame *dst, const AVFrame *src)
 {
     AVFrame *map;
     int err;
 
     if (src->width > hwfc->width || src->height > hwfc->height)
         return AVERROR(EINVAL);
 
     map = av_frame_alloc();
     if (!map)
         return AVERROR(ENOMEM);
     map->format = src->format;
 
     err = drm_map_frame(hwfc, map, dst, AV_HWFRAME_MAP_WRITE |
                                         AV_HWFRAME_MAP_OVERWRITE);
     if (err)
         goto fail;
 
     map->width  = src->width;
     map->height = src->height;
 
     err = av_frame_copy(map, src);
     if (err)
         goto fail;
 
     err = 0;
 fail:
     av_frame_free(&map);
     return err;
 }
 
 static int drm_map_from(AVHWFramesContext *hwfc, AVFrame *dst,
                         const AVFrame *src, int flags)
 {
     int err;
 
     if (hwfc->sw_format != dst->format)
         return AVERROR(ENOSYS);
 
     err = drm_map_frame(hwfc, dst, src, flags);
     if (err)
         return err;
 
     err = av_frame_copy_props(dst, src);
     if (err)
         return err;
 
     return 0;
 }
 
 const HWContextType ff_hwcontext_type_drm = {
     .type                   = AV_HWDEVICE_TYPE_DRM,
     .name                   = "DRM",
 
     .device_hwctx_size      = sizeof(AVDRMDeviceContext),
 
     .device_create          = &drm_device_create,
 
     .frames_get_buffer      = &drm_get_buffer,
 
     .transfer_get_formats   = &drm_transfer_get_formats,
     .transfer_data_to       = &drm_transfer_data_to,
     .transfer_data_from     = &drm_transfer_data_from,
     .map_from               = &drm_map_from,
 
     .pix_fmts = (const enum AVPixelFormat[]) {
         AV_PIX_FMT_DRM_PRIME,
         AV_PIX_FMT_NONE
     },
 };