首先確保在 linux 下已經調好 mipi 驅動，使用 uboot 已經移植好了 mipi 相關驅動，只需要點亮屏幕背光，以及屏相關的初始化。
首先需要在 Main.c 中增加 pwm 初始化的代碼，pwm 初始化寫寄存器即可，但是需要注意，需要將 PWM_OUT 和 pwm 時鐘打開，再去配置寄存器：

//open pwm,start screen light back//PWM_OUT0writel(1,0x04058074);//PERI_CRG101 PWM clockwritel(0x008AAA80,0x04510194);//PWM0 REGwritel(0,0x045a000c);writel(1000,0x045a0000);writel(500,0x045a0004);writel(10,0x045a0008);writel(5,0x045a000c);

然后在 cmd_vo_hi3519av100.c do_startvo 函數，會調到 mipi_tx_display，調到 Mipi_tx.c ，需要在此完成自己屏幕初始化的部分：

/ * name : mipi_tx_display* desc : mipi_tx interface display.*/ int mipi_tx_display(unsigned int vosync) {int ret;combo_dev_cfg_t *mipi_tx_config;printf("this is mipi_tx begin,vosync:%d.\n",vosync);/* mipi_tx drv init.*/mipi_tx_module_init();switch (vosync) {case VO_OUTPUT_576P50:mipi_tx_config = &g_mipi_tx_720x576_50_config;break;case VO_OUTPUT_720P60:mipi_tx_config = &g_mipi_tx_1280x720_60_config;break;case VO_OUTPUT_1080P60:mipi_tx_config = &g_mipi_tx_1920x1080_60_config;break;case VO_OUTPUT_1024x768_60:mipi_tx_config = &g_mipi_tx_1024x768_60_config;break;case VO_OUTPUT_1280x1024_60:mipi_tx_config = &g_mipi_tx_1280x1024_60_config;break;case VO_OUTPUT_720x1280_60:printf("%s,%d,vo sync: VO_OUTPUT_720x1280_60\n", __FUNCTION__, __LINE__);mipi_tx_config = &g_mipi_tx_720x1280_60_config;break;case VO_OUTPUT_1080x1920_60:mipi_tx_config = &g_mipi_tx_1080x1920_60_config;break;default:printf("%s,%d,unsupported vo sync\n", __FUNCTION__, __LINE__);mipi_tx_config = &g_mipi_tx_1920x1080_60_config;break;}/* step 1 : config mipi_tx controller.*/ret = mipi_tx_ioctl(HI_MIPI_TX_SET_DEV_CFG, (unsigned long)mipi_tx_config);if (ret != 0) {printf("MIPI_TX SET_DEV_CONFIG failed\n");return -1;}/* step 2 : init display device (do it yourself ).*/mipi_tx_screen_init();udelay(1000);/* step 3 : enable mipi_tx controller.*/ret = mipi_tx_ioctl(HI_MIPI_TX_ENABLE, (unsigned long)0);if (ret != 0) {printf("MIPI_TX enable failed\n");return -1;}printf("this is mipi_tx end.\n");return 0; }

其中，step 2 的 mipi_tx_screen_init 是我們需要完成的屏幕初始化函數，這里就是給 mipi_tx 發送命令，初始化屏幕：

void mipi_tx_screen_init(void){//mipi_tx param.char cmd[]={0xFF,0x01,0xFB,0x01,0xFF,0x02,0xFB,0x01, /******* 命令特別長，僅示例 ********/0xE5,0x03,0xE6,0xA8,0xE7,0x03,0xE8,0xC8,0xE9,0x03,0xEA,0xFF,0xFF,0x00,0xFB,0x01};unsigned int cmd_size=2;char cmd1[] ={0x11,0x29};cmd_info_t cmd_info;unsigned int cmd1_size=1;unsigned int loop;long ret;printf("func:%s line:%d send cmd begin.\n",__FUNCTION__,__LINE__);for(loop=0; loop<sizeof(cmd)/cmd_size; loop++) {udelay(loop == 12 ? 10000 : 1000);cmd_info.devno = 0;cmd_info.cmd_size = (((unsigned short)cmd[loop*cmd_size+1])<<8)+(cmd[loop*cmd_size]);cmd_info.data_type = 0x15;cmd_info.cmd = NULL;//printf("func:%s line:%d cmd_size = %x = %x + %x %d\n",__FUNCTION__,__LINE__,cmd_info.cmd_size,//((unsigned short)cmd[loop*cmd_size])<<8,cmd[loop*cmd_size+1],loop);ret = mipi_tx_ioctl(HI_MIPI_TX_SET_CMD, (unsigned long)(&cmd_info));if (0 != ret) {printf("MIPI_TX SET CMD failed\n");}}for(loop=0; loop<sizeof(cmd1)/cmd1_size; loop++) {cmd_info.devno = 0;cmd_info.cmd_size = cmd1[loop];cmd_info.data_type = 0x15;cmd_info.cmd = NULL;//printf("func:%s line:%d cmd_size1 = %x %d\n",__FUNCTION__,__LINE__,cmd_info.cmd_size,loop);ret = mipi_tx_ioctl(HI_MIPI_TX_SET_CMD, (unsigned long)(&cmd_info));if (0 != ret) {printf("MIPI_TX SET CMD failed\n");}udelay(10000);}printf("func:%s line:%d send cmd end.\n",__FUNCTION__,__LINE__); }

完成上述修改后，就可以在 uboot 命令加載開機畫面了，這里 uboot 燒寫在 0 大小 768K ，logo 燒寫在 768K ，大小 256K，之后是內核和文件系統等，代碼如下，

void ShowBootLogo(void) {//open pwm,start screen light back//PWM_OUT0writel(1,0x04058074);//PERI_CRG101 PWM clockwritel(0x008AAA80,0x04510194);//PWM0 REGwritel(0,0x045a000c);writel(1000,0x045a0000);writel(500,0x045a0004);writel(10,0x045a0008);writel(5,0x045a000c);//start logosetenv("jpeg_addr", "0x52000000"); //image addr startsetenv("jpeg_size", "0xe671"); //image file sizesetenv("jpeg_emar_buf","0x52200000");setenv("vobuf", "0x52400000"); //image decode addr//run commandsrun_command("nand read 0x52000000 0xc0000 0xe671",0); //read logo filerun_command("decjpg 0",0); //decode jpg from jpeg_addr to vobufrun_command("setvobg 0 0",0); //set vo background to blackrun_command("startvo 0 16384 45",0); //start vo with mipi 1080*1920 60psrun_command("startvl 0 0x52400000 768 180 824 720 190",0);//startvl,768 is decjpg picture stride,be sure [x y w h]/2==0 }

然后，在 main_loop 中調用 ShowBootLogo 即可。
還需要注意的是，在 uboot 中做了 pwm 初始化和 vo 0 顯示，所以在 hifb 啟動之后，最好先將 vo 0 關閉，再進行其他初始化，避免造成閃爍等現象。

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