G2D主要功能：1）旋转：支持90、180、270旋转；2）scale：放缩；

3）镜像反转：H / V；

4）透明叠加：实现两个rgb图片叠加；

(资料图)

5）格式转换：yuv转rgb等多种格式相互间转换；

6）矩形填充，等诸多功能；

G2D配置

源码目录

tina-v853-docker/kernel/linux-4.9/drivers/char/sunxi_g2d

make kernel_menuconfig 配置

Device Drivers > Character devices > sunxi g2d driver

Device Tree 设备树配置

sun8iw21p1.dtsi路径：

tina-v853-docker/kernel/linux-4.9/arch/arm/boot/dts/sun8iw21p1.dtsi

g2d: g2d@05410000 {   compatible = "allwinner,sunxi-g2d";   reg = <0x0 0x05410000 0x0 0xbffff>;   interrupts = ;   clocks = <&clk_g2d>;   iommus = <&mmu_aw 3 1>;   status = "okay";  };

注：status 要设定为“okay” 状态。

重新编译内核

使用烧录工具PhoenixSuit 将编译打包好的img镜像烧录到开发板。

adb shell 打开控制终端查看设备节点G2D：

通过G2D设备节点进行操作

static int SampleG2d_G2dOpen(SAMPLE_G2D_CTX *p_g2d_ctx){  int ret = 0;  p_g2d_ctx->mG2dFd = open("/dev/g2d", O_RDWR, 0);  if (p_g2d_ctx->mG2dFd < 0)  {    aloge("fatal error! open /dev/g2d failed");    ret = -1;  }  return ret;}

G2D sample具体应用

G2D sample目录

进行rotation，scale，格式转换

具体实现：将 nv21 格式的1920x1080图转换成rgb888 格式并放缩为640x360 大小。具体用到两个功能，格式转换和放缩。

首先根据1920x1080 nv21 格式以及 640x360 rgb888 格式申请虚拟地址空间以及转换成物理地址（注意：g2d 转换是在物理地址中完成的）

1920x1080 nv21 格式空间大小（输入文件）：

Y 占 19201080 = 2073600 字节

UV 占 19201080 / 2 = 1036800 字节

640x360 rgb888 格式空间大小（输出文件）：

RGB 占 6403603 = 691200 字节

另外：虚拟地址转换成物理地址使用如下函数：

g2d_getPhyAddrByVirAddr（）

申请虚拟空间并转换成物理空间完整函数如下：

static int PrepareFrmBuff(SAMPLE_G2D_CTX *p_g2d_ctx){  SampleG2dConfig *pConfig = NULL;  unsigned int size = 0;  pConfig = &p_g2d_ctx->mConfigPara;    p_g2d_ctx->src_frm_info.frm_width = pConfig->mSrcWidth;  p_g2d_ctx->src_frm_info.frm_height = pConfig->mSrcHeight;  p_g2d_ctx->dst_frm_info.frm_width = pConfig->mDstWidth;  p_g2d_ctx->dst_frm_info.frm_height = pConfig->mDstHeight;  size = ALIGN(p_g2d_ctx->src_frm_info.frm_width, 16)*ALIGN(p_g2d_ctx->src_frm_info.frm_height, 16);  if(pConfig->mPicFormat == MM_PIXEL_FORMAT_YVU_SEMIPLANAR_420 || pConfig->mPicFormat == MM_PIXEL_FORMAT_YUV_SEMIPLANAR_420)  {    p_g2d_ctx->src_frm_info.p_vir_addr[0] = (void *)g2d_allocMem(size);    if(NULL == p_g2d_ctx->src_frm_info.p_vir_addr[0])    {      aloge("malloc_src_frm_y_mem_failed");      return -1;    }    p_g2d_ctx->src_frm_info.p_vir_addr[1] = (void *)g2d_allocMem(size/2);    if(NULL == p_g2d_ctx->src_frm_info.p_vir_addr[1])    {      g2d_freeMem(p_g2d_ctx->src_frm_info.p_vir_addr[0]);      aloge("malloc_src_frm_c_mem_failed");        return -1;    }    p_g2d_ctx->src_frm_info.p_phy_addr[0] = (void *)g2d_getPhyAddrByVirAddr(p_g2d_ctx->src_frm_info.p_vir_addr[0]);     p_g2d_ctx->src_frm_info.p_phy_addr[1] = (void *)g2d_getPhyAddrByVirAddr(p_g2d_ctx->src_frm_info.p_vir_addr[1]);  } if(pConfig->mDstPicFormat == MM_PIXEL_FORMAT_RGB_888) {  size = p_g2d_ctx->dst_frm_info.frm_width * p_g2d_ctx->dst_frm_info.frm_height * 3;  p_g2d_ctx->dst_frm_info.p_vir_addr[0] = (void *)g2d_allocMem(size);  if(NULL == p_g2d_ctx->dst_frm_info.p_vir_addr[0])  {   if(p_g2d_ctx->src_frm_info.p_vir_addr[0] != NULL)   {    g2d_freeMem(p_g2d_ctx->src_frm_info.p_vir_addr[0]);    }   if(p_g2d_ctx->src_frm_info.p_vir_addr[1] != NULL)   {    g2d_freeMem(p_g2d_ctx->src_frm_info.p_vir_addr[1]);   }   aloge("malloc_dst_frm_y_mem_failed");   return -1;  }  p_g2d_ctx->dst_frm_info.p_phy_addr[0] = (void *)g2d_getPhyAddrByVirAddr(p_g2d_ctx->dst_frm_info.p_vir_addr[0]);  }  return 0; }

通过fopen 传菜间两个文件句柄，fd_in fd_out 用来操作输入输出两个文件资源。

p_g2d_ctx->fd_in = fopen(p_g2d_ctx->mConfigPara.SrcFile,"r");    if(NULL == p_g2d_ctx->fd_in)    {      aloge("open src file failed");      ret = -1;      goto _err2;    }    fseek(p_g2d_ctx->fd_in, 0, SEEK_SET);      p_g2d_ctx->fd_out = fopen(p_g2d_ctx->mConfigPara.DstFile, "wb");      if (NULL == p_g2d_ctx->fd_out)      {        aloge("open out file failed");        ret = -1;        goto _err2;      }      fseek(p_g2d_ctx->fd_out, 0, SEEK_SET);

读出 1920x1080 nv21 图资放入 虚拟空间

read_len = p_g2d_ctx->src_frm_info.frm_width * p_g2d_ctx->src_frm_info.frm_height;    if(pConfig->mPicFormat == MM_PIXEL_FORMAT_YVU_SEMIPLANAR_420|| pConfig->mPicFormat == MM_PIXEL_FORMAT_YUV_SEMIPLANAR_420)    {      size1 = fread(p_g2d_ctx->src_frm_info.p_vir_addr[0] , 1, read_len, p_g2d_ctx->fd_in);      if(size1 != read_len)      {        aloge("read_y_data_frm_src_file_invalid");      }      size2 = fread(p_g2d_ctx->src_frm_info.p_vir_addr[1], 1, read_len /2, p_g2d_ctx->fd_in);      if(size2 != read_len/2)      {        aloge("read_c_data_frm_src_file_invalid");      }      fclose(p_g2d_ctx->fd_in);      g2d_flushCache((void *)p_g2d_ctx->src_frm_info.p_vir_addr[0], read_len);      g2d_flushCache((void *)p_g2d_ctx->src_frm_info.p_vir_addr[1], read_len/2);    }

打开g2d 初始化，并开始转换

ret = SampleG2d_G2dOpen(p_g2d_ctx);  if (ret < 0)  {    aloge("fatal error! open /dev/g2d fail!");    goto _err2;  }  ret = SampleG2d_G2dConvert(p_g2d_ctx);  if (ret < 0)  {    aloge("fatal error! g2d convert fail!");    goto _close_g2d;  }//具体转化函数：static int SampleG2d_G2dConvert_scale(SAMPLE_G2D_CTX *p_g2d_ctx){  int ret = 0;  g2d_blt_h blit;  g2d_fmt_enh eSrcFormat, eDstFormat;   SampleG2dConfig *pConfig = NULL;  pConfig = &p_g2d_ctx->mConfigPara;  ret = convert_PIXEL_FORMAT_E_to_g2d_fmt_enh(pConfig->mPicFormat, &eSrcFormat);  if(ret!=SUCCESS)  {    aloge("fatal error! src pixel format[0x%x] is invalid!", pConfig->mPicFormat);    return -1;  }  ret = convert_PIXEL_FORMAT_E_to_g2d_fmt_enh(pConfig->mDstPicFormat, &eDstFormat);  if(ret!=SUCCESS)  {    aloge("fatal error! dst pixel format[0x%x] is invalid!", pConfig->mPicFormat);    return -1;  }  //config blit  memset(&blit, 0, sizeof(g2d_blt_h));  if(0 != pConfig->mDstRotate)  {    aloge("fatal_err: rotation can"t be performed when do scaling");  }  blit.flag_h = G2D_BLT_NONE_H;    // angle rotation used//  switch(pConfig->mDstRotate)//  {//    case 0://      blit.flag_h = G2D_BLT_NONE_H;  //G2D_ROT_0, G2D_BLT_NONE_H//      break;//    case 90://      blit.flag_h = G2D_ROT_90;//      break;//    case 180://      blit.flag_h = G2D_ROT_180;//      break;//    case 270://      blit.flag_h = G2D_ROT_270;//      break;//    default://      aloge("fatal error! rotation[%d] is invalid!", pConfig->mDstRotate);//      blit.flag_h = G2D_BLT_NONE_H;//      break;//  }  //blit.src_image_h.bbuff = 1;  //blit.src_image_h.color = 0xff;  blit.src_image_h.format = eSrcFormat;  blit.src_image_h.laddr[0] = (unsigned int)p_g2d_ctx->src_frm_info.p_phy_addr[0];  blit.src_image_h.laddr[1] = (unsigned int)p_g2d_ctx->src_frm_info.p_phy_addr[1];  blit.src_image_h.laddr[2] = (unsigned int)p_g2d_ctx->src_frm_info.p_phy_addr[2];  //blit.src_image_h.haddr[] =   blit.src_image_h.width = p_g2d_ctx->src_frm_info.frm_width;  blit.src_image_h.height = p_g2d_ctx->src_frm_info.frm_height;  blit.src_image_h.align[0] = 0;  blit.src_image_h.align[1] = 0;  blit.src_image_h.align[2] = 0;  blit.src_image_h.clip_rect.x = pConfig->mSrcRectX;  blit.src_image_h.clip_rect.y = pConfig->mSrcRectY;  blit.src_image_h.clip_rect.w = pConfig->mSrcRectW;  blit.src_image_h.clip_rect.h = pConfig->mSrcRectH;  blit.src_image_h.gamut = G2D_BT601;  blit.src_image_h.bpremul = 0;  //blit.src_image_h.alpha = 0xff;  blit.src_image_h.mode = G2D_PIXEL_ALPHA;  //G2D_PIXEL_ALPHA, G2D_GLOBAL_ALPHA  blit.src_image_h.fd = -1;  blit.src_image_h.use_phy_addr = 1;  //blit.dst_image_h.bbuff = 1;  //blit.dst_image_h.color = 0xff;  blit.dst_image_h.format = eDstFormat;  blit.dst_image_h.laddr[0] = (unsigned int)p_g2d_ctx->dst_frm_info.p_phy_addr[0];  blit.dst_image_h.laddr[1] = (unsigned int)p_g2d_ctx->dst_frm_info.p_phy_addr[1];  blit.dst_image_h.laddr[2] = (unsigned int)p_g2d_ctx->dst_frm_info.p_phy_addr[2];  //blit.dst_image_h.haddr[] =   blit.dst_image_h.width = p_g2d_ctx->dst_frm_info.frm_width;  blit.dst_image_h.height = p_g2d_ctx->dst_frm_info.frm_height;  blit.dst_image_h.align[0] = 0;  blit.dst_image_h.align[1] = 0;  blit.dst_image_h.align[2] = 0;  blit.dst_image_h.clip_rect.x = pConfig->mDstRectX;  blit.dst_image_h.clip_rect.y = pConfig->mDstRectY;  blit.dst_image_h.clip_rect.w = pConfig->mDstRectW;  blit.dst_image_h.clip_rect.h = pConfig->mDstRectH;  blit.dst_image_h.gamut = G2D_BT601;  blit.dst_image_h.bpremul = 0;  //blit.dst_image_h.alpha = 0xff;  blit.dst_image_h.mode = G2D_PIXEL_ALPHA;  //G2D_PIXEL_ALPHA, G2D_GLOBAL_ALPHA  blit.dst_image_h.fd = -1;  blit.dst_image_h.use_phy_addr = 1;  ret = ioctl(p_g2d_ctx->mG2dFd, G2D_CMD_BITBLT_H, (unsigned long)&blit);  if(ret < 0)  {    aloge("fatal error! bit-block(image) transfer failed[%d]", ret);    system("cd /sys/class/sunxi_dump;echo 0x14A8000,0x14A8100 > dump;cat dump");  }  return ret;}

转化完成后将640x360 rgb888 图资通过fd_out句柄存储起来

if(pConfig->mDstPicFormat == MM_PIXEL_FORMAT_RGB_888)    {      out_len = p_g2d_ctx->dst_frm_info.frm_width * p_g2d_ctx->dst_frm_info.frm_height *3;      g2d_flushCache((void *)p_g2d_ctx->dst_frm_info.p_vir_addr[0], out_len);      fwrite(p_g2d_ctx->dst_frm_info.p_vir_addr[0], 1, out_len, p_g2d_ctx->fd_out);    }

转化步骤总结

通过步骤3中的模块化分析，可以看出g2d 转化大概分为一下步骤：

为打开 iomen 初始化；

为src以及dst图资申请虚拟地址空间并转换成物理地址空间；

将src图资放入虚拟地址空间，然后自动映射到物理地址空间；

打开g2d 设备节点进行转换（最重要的一环，可以通过手册分析具体怎么转换的）；

将转换好的dst图资保存起来；

审核编辑：刘清