1. g2d 模块概述
g2d 主要功能：
1）旋转：支持90、180、270旋转；
2）镜像反转：H / V;
3) scale：放缩
4）格式转换：yuv 转 rgb 等，多种格式相互间转换；
5）透明叠加功能：实现两个rgb图片叠加；
6）矩形填充，等诸多功能；
2. g2d 配置
1）源码目录：tina-v853-docker/kernel/linux-4.9/drivers/char/sunxi_g2d
2）make kernel_menuconfig 配置
Device Drivers > Character devices > sunxi g2d driver
按空格键选中【*】
![309b3811-659e-4000-8634-7e867717ab87-image.png]()
3）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 = <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&clk_g2d>;
iommus = <&mmu_aw 3 1>;
status = "okay";
};
status 要设定为“okay” 状态。
4）重新编译内核
mkernel
make -j1 V=s
pack
使用烧录工具PhoenixSuit 将路径：tina-v853-docker/out/v851s/lizard/openwrt/v851s_linux_lizard_uart0.img 下的img 镜像烧录到开发板。
adb shell 打开控制终端查看设备节点G2D：
![483651d3-abc6-4e99-9a22-e5bac90a0194-image.png]()
5）通过G2D 设备节点，对g2d 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;
}
3. 详解 eyesee-mpp 中g2d sample 具体应用
1）eyesee-mpp 中 g2d sample 编译与执行请参考另一篇帖子
链接文本
2）g2d sample 目录
![3e6039cc-ec14-4724-942b-92852b697e74-image.png]()
3）运用 g2d 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。
步骤如下：
1））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）：
![a804f646-d146-4e43-8f2f-9ee1352cfc8e-image.png]()
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：
在文件 tina-v853-docker/platform/allwinner/eyesee-mpp/middleware/sun8iw21/sample/sample_g2d/sample_g2d.c/sample_g2d.c 中
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;
}
2））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);
3））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);
}
4））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;
}
5））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);
}
4. 总结转化步骤
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：
1）为打开 iomen 初始化；
2）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；
3）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；
4）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）；
5）将转换好的dst图资保存起来；
