商顯板領(lǐng)域板卡中有許多擴(kuò)展的端子，且這些端子是帶mcu并且包含內(nèi)置固件程序，為了后續(xù)的維護(hù)通常 需要有升級功能。5450 就是一款擴(kuò)展芯片，將手機(jī)信號轉(zhuǎn)換成DP 信號，主板上的DP轉(zhuǎn)換芯片再將DP信號 轉(zhuǎn)換HDMI 信號最后輸入給主板顯示出來。下面我們圍繞5450 來分享一下升級的流程。

1. 主體流程

如果是原廠提供的PC 工具端的基本升級流程： 大體就是啟動(dòng)VENDOR_CMD_ENABLE，FLASH_ACCESS_ENABLE，SMBUS_REASE_FLASH，CHECK_BANK，WRITE_BANK，FLASH_ACCESS_DISABLE，SMBUS_ISP_VALIDATION，RESET_TO_FLASH。
其中GET_IC_STATUS 獲取芯片狀態(tài)信息。

詳細(xì)信息可以查看文檔：
https://download.csdn.net/download/kehyuanyu/12629812

啟動(dòng)mcuSMBUS功能

操作碼為0x01， 發(fā)送三個(gè)字節(jié)的指令“0xDA,0x0B,0x01”，code 如下：

int nFd = open(RTL5450_MASTER_DEV, O_RDWR);if(nFd < 0){printf("[%s][%d] open %s failed !\n", __FUNCTION__,__LINE__,RTL5450_MASTER_DEV);return FALSE;}// 1. enable smbus functiondo{MAPI_U8 data[5] = {0x01,0x03,0xDA,0x0B,0x01};bRet = sendCmdToRtl5450(nFd, data, 5);if(!bRet){printf("[%s][%d] send cmd <0x01,0x03,0xDA,0x0B,0x01> failed. Count [%d]\n",\__FUNCTION__,__LINE__,uCount);break;}uCount = 0;while(uCount++ < 350){usleep(1000);bRet = recvFeedbackFromRtl5450Sigle(nFd,&u8FeedBuf);if(bRet && u8FeedBuf == 0x01){bStep1 = MAPI_TRUE;break;}else{continue;}}} while (0);

sendCmdToRtl5450 是發(fā)送指令給5450

static MAPI_BOOL sendCmdToRtl5450(int nDevFd, MAPI_U8 u8Cmd[], MAPI_U8 u8Size) {int nRet = -1;struct i2c_msg msg;struct i2c_rdwr_ioctl_data ioctl_data = {0};msg.addr = RTL5450_IIC_ADDR;msg.flags = I2C_SMBUS_WRITE; /* write */msg.len = u8Size;msg.buf = u8Cmd;ioctl_data.msgs = &msg;ioctl_data.nmsgs = 1;nRet = ioctl(nDevFd, I2C_RDWR, &ioctl_data);if( nRet < 0){printf("[%s][%d] ioctl rtl5450 i2c reg[0x%02x] failed! nRet: = %d, errno: %d, error: %s. \n", \__FUNCTION__,__LINE__,u8Cmd[0],nRet, errno,strerror(errno));return MAPI_FALSE;}return MAPI_TRUE; }

其中 RTL5450_IIC_ADDR 為typec 7位的設(shè)備地址，kernel 會(huì)根據(jù)上層的操作(讀/寫)來補(bǔ)全最后一位。
recvFeedbackFromRtl5450Sigle 獲取指令執(zhí)行后，5450 發(fā)過來的返回值，使用與所有指令執(zhí)行后的返回值

// GET_PING_STATUS static MAPI_BOOL recvFeedbackFromRtl5450Sigle(int nDevFd, MAPI_U8 *pu8FeedBuf) {struct i2c_msg msg;struct i2c_rdwr_ioctl_data data_ioctl;msg.addr = RTL5450_IIC_ADDR;msg.flags = I2C_SMBUS_READ;msg.len = 1;msg.buf = pu8FeedBuf;data_ioctl.msgs = &msg;data_ioctl.nmsgs = 1;if(ioctl(nDevFd, I2C_RDWR, &data_ioctl) < 0){printf("[%s][%d] read back value failed! \n", __FUNCTION__,__LINE__);return MAPI_FALSE;}return MAPI_TRUE; }

通過msg.buf 返回上調(diào)指令的執(zhí)行結(jié)果。

2. 獲取芯片信息

操作碼（亦寄存器）為0x3A，發(fā)送三個(gè)字節(jié)指令"0x00 0x00 0x14"到5450 ,其中主要是操作碼，及最后一個(gè)0x14（表示將返回0x14 個(gè)字節(jié)的狀態(tài)信息）。

// 2. get ic statusdo{MAPI_U8 data[5] = {0x3A,0x03,0x00,0x00,0x14};MAPI_U8 u8CmdCode = 0x00;MAPI_BOOL bRet = MAPI_FALSE;bRet = sendCmdToRtl5450(nFd, data, 5);if(!bRet){printf("[%s][%d] send cmd <0x3A,0x03,0x00,0x00,0x14> failed. Count [%d]\n",\__FUNCTION__,__LINE__,uCount);break;}uCount = 0;while(uCount++ < 350){usleep(1000);u8FeedBuf = 0x00;bRet = recvFeedbackFromRtl5450Sigle(nFd,&u8FeedBuf);if(bRet && u8FeedBuf == 0x01){break;}else{continue;}}uCount = 0;u8CmdCode = 0x80;while(uCount++ < 350){usleep(100);memset(u8FeedBufs, 0x00, sizeof(u8FeedBufs));recvFeedbackFromRtl5450FromReg(nFd, u8CmdCode, u8FeedBufs, sizeof(u8FeedBufs)/sizeof(u8FeedBufs[0]));if(bRet && u8FeedBufs[0] == 0x14){bStep2 = MAPI_TRUE;break;}else{continue;}}}while(0);

recvFeedbackFromRtl5450Sigle 返回值為0x01 ，表示5450 正常收到請求GET_IC_STATUS的指令，接著通過recvFeedbackFromRtl5450FromReg獲取0x14 (20)個(gè)的信息

static MAPI_BOOL recvFeedbackFromRtl5450FromReg(int nDevFd, MAPI_U8 u8Cmd, MAPI_U8 *pu8FeedBuf, MAPI_U8 u8FeedSize) {struct i2c_msg msg[2];struct i2c_rdwr_ioctl_data data_ioctl;MAPI_U8 ucAddr = u8Cmd;msg[0].addr = RTL5450_IIC_ADDR;msg[0].flags = I2C_SMBUS_WRITE;msg[0].len = 1;msg[0].buf = &ucAddr; // cmd or regmsg[1].addr = RTL5450_IIC_ADDR;msg[1].flags = I2C_M_RD;msg[1].len = u8FeedSize;msg[1].buf = pu8FeedBuf;data_ioctl.msgs = msg;data_ioctl.nmsgs = 2;if(ioctl(nDevFd, I2C_RDWR, &data_ioctl) < 0){printf("[%s][%d] read back value failed! \n", __FUNCTION__,__LINE__);return MAPI_FALSE;}return MAPI_TRUE; }

成功之后，解析這個(gè)20個(gè)bytes，其中byte【1】表示Rom code 還是MCM flash code，而byte【15】為0x10 時(shí)表示運(yùn)行在bank1，其他值則表示運(yùn)行在bank0，這個(gè)會(huì)影響寫flash的地址。

3. 啟動(dòng)falsh訪問權(quán)限

操作碼0x0a, 發(fā)送三個(gè)字節(jié)0xDA,0x0B,0x03 到5450

// 3. falsh enable accessdo{MAPI_U8 data[5] = {0x01,0x03,0xDA,0x0B,0x03};MAPI_BOOL bRet = MAPI_FALSE;bRet = sendCmdToRtl5450(nFd, data, 5);if(!bRet){printf("[%s][%d] send cmd <0x01,0x03,0xDA,0x0B,0x03> failed. Count [%d]\n",\__FUNCTION__,__LINE__,uCount);break;}uCount = 0;while(uCount++ < 350){u8FeedBuf = 0x00;bRet = recvFeedbackFromRtl5450Sigle(nFd,&u8FeedBuf);if(bRet && u8FeedBuf == 0x01){bStep3 = MAPI_TRUE;break;}else{continue;}usleep(1000);}} while (0);

4. 擦寫flash

static MAPI_BOOL writeBinTo5450m(MAPI_U8 u8CodeRun, const char* filename, int nFd) {MAPI_U8 u8Step4CmdCode1 = 0x00;MAPI_U8 u8Step4CmdCode2 = 0x00;char binFile[1024];MAPI_U8 u8TmpBin[32] = {0x00};MAPI_U8 u8WData[34] = {0x00};MAPI_U8 u8RUnitLen = 0x1D;MAPI_BOOL bWRet = MAPI_FALSE;const MAPI_U8 u8RUnitHeadLen = 5; // cmd, byte count, addr_l, addr_h,wData_countconst MAPI_U32 nBankHalfSize = 65536; // 64KFILE *pFHandle = NULL;int nLen = 0;MAPI_U16 uReadCnt = 0;MAPI_U32 uWAddr = 0x0000;MAPI_U16 uWUsdAddr = 0x0000;MAPI_U32 u32RTotal = 0x0000;MAPI_U8 u8RItemSize = 29;MAPI_U8 u8RItem = 1;MAPI_U8 u8LoopCnt = 0;if(u8CodeRun == 0x10) // bank1{// bank 0 cmd codeu8Step4CmdCode1 = 0x04;u8Step4CmdCode2 = 0x06;}else // bank0{// bank 1 cmd codeu8Step4CmdCode1 = 0x13;u8Step4CmdCode2 = 0x14;}printf("[%s][%d] will upgrade %s \n", __FUNCTION__,__LINE__,u8CodeRun ? "bank0" : "bank1");printf("[%s][%d] cmd code1: 0x%02x , cmd: code2 0x%02x .\n", __FUNCTION__,__LINE__,u8Step4CmdCode1,u8Step4CmdCode2);memset(binFile,0x00,sizeof(binFile));memcpy(binFile,filename,strlen(filename));pFHandle = fopen(binFile, "r");if(pFHandle == NULL){printf("[%s][%d] open %s failed! \n",__FUNCTION__,__LINE__,binFile);return MAPI_FALSE;}fseek(pFHandle, 0, SEEK_END);nLen = ftell(pFHandle);fseek(pFHandle, 0, SEEK_SET);printf("[%s][%d] file %s size: %d[0x%05x] \n",__FUNCTION__,__LINE__,binFile,nLen,nLen);while(TRUE){MAPI_BOOL bBackVal = MAPI_FALSE;u8RItem = (u8RItem % 10) == 0 ? 1 : (u8RItem % 10) ;if(u8RItem % 9 == 0){u8RItemSize = 24;}else{u8RItemSize = 29;}// init bufmemset(u8TmpBin, 0x00, sizeof(u8TmpBin));memset(u8WData, 0x00, sizeof(u8WData));u8RUnitLen = fread(u8TmpBin, sizeof(char), u8RItemSize, pFHandle);if(u8RUnitLen <= 0){int nCurPosition = ftell(pFHandle);if(nCurPosition >= nLen){break;}}u32RTotal = u32RTotal + u8RUnitLen;if(u32RTotal < nBankHalfSize){u8WData[0] = u8Step4CmdCode1;}else{u8RItem = 1;u8WData[0] = u8Step4CmdCode2;}#if (KERNEL_I2C_DEBUG == 1)if(u32RTotal % 1024 == 0){printf("[%s][%d] read item ( %d KB) from bin, two banks size: %d KB . \n", \__FUNCTION__,__LINE__,(u32RTotal/1024),(nLen/1024));}#endif// byte countu8WData[1] = u8RUnitLen + (u8RUnitHeadLen - 2); // remove 2 byte(cmd , byte count)uWUsdAddr = uWAddr % nBankHalfSize;// ADDR_Lu8WData[2] = (MAPI_U8)uWUsdAddr&0x00FF;// ADDR_Hu8WData[3] = ((MAPI_U8)((uWUsdAddr&0xFF00) >> 8));// WData_countu8WData[4] = u8RUnitLen;// data1 ~ dataNmemcpy(u8WData + u8RUnitHeadLen, u8TmpBin, u8RUnitLen);bWRet = sendCmdToRtl5450(nFd, u8WData, (u8RUnitLen+u8RUnitHeadLen));if(!bWRet){printf("[%s][%d] wirte bin data to 5450 failed\n", __FUNCTION__,__LINE__);break;}u8LoopCnt = 0;while(u8LoopCnt++ < 350){// MAPI_U8 u8CmdCode = u8WData[0];MAPI_BOOL bRetFeedval = MAPI_FALSE;MAPI_U8 u8FeedBuf = 0x00;usleep(1000);bRetFeedval = recvFeedbackFromRtl5450Sigle(nFd,&u8FeedBuf);if(bRetFeedval && u8FeedBuf == 0x01){bBackVal = MAPI_TRUE;break;}else{continue;}}if(!bBackVal){printf("[%s][%d] get back value failed , when wirte date to 0x%04x\n",\__FUNCTION__,__LINE__,uWAddr);break;}uReadCnt++;u8RItem++;uWAddr = uWAddr + u8RUnitLen;}if(feof(pFHandle) != 0 || (ftell(pFHandle) == nLen)){printf("[%s][%d] wirte bin file completed .\n", __FUNCTION__,__LINE__);fclose(pFHandle);return MAPI_TRUE;}printf("[%s][%d] write %d bytes to dev [addr: 0x%04x], [failed] \n",\__FUNCTION__,__LINE__,u8RUnitLen,uWAddr);fclose(pFHandle);return MAPI_FALSE; }

bank0 ： 0~ 128K, bank1: 128K~256K。 根據(jù)GET_IC_STATUS獲取信息，如果運(yùn)行在bank1就寫bank0，如果運(yùn)行在bank0 就寫bank1.
根據(jù)對應(yīng)操作碼，將從bin文件中讀取的數(shù)據(jù)封裝成包，寫入mcu 的flash中。一個(gè)輪回寫8次29bytes，接著寫1次24bytes，共計(jì)256 bytes，如此反復(fù)512次即可燒錄完128K數(shù)據(jù)。

5. 關(guān)閉smbus

do{MAPI_U8 data[5] = {0x01,0x03,0xDA,0x0B,0x01};MAPI_BOOL bRet = MAPI_FALSE;memset(u8FeedBufs, 0x00, sizeof(u8FeedBufs));bRet = sendCmdToRtl5450(nFd, data, 5);if(!bRet){printf("[%s][%d] send cmd <0x01,0x03,0xDA,0x0B,0x01> failed. Count [%d]\n",\__FUNCTION__,__LINE__,uCount);break;}uCount = 0;while(uCount++ < 350){usleep(1000);u8FeedBuf = 0x00;bRet = recvFeedbackFromRtl5450Sigle(nFd,&u8FeedBuf);if(bRet && u8FeedBuf == 0x01){bStep5_1 = MAPI_TRUE;break;}else{continue;}}} while (0);

6. 校驗(yàn)數(shù)據(jù)

操作碼0x01,發(fā)送三字節(jié)數(shù)據(jù)0xDA,0x0B,0x01給mcu

// 5. smbus isp validationdo{MAPI_U8 data[3] = {0x16,0x01,0x01};MAPI_BOOL bRet = MAPI_FALSE;bRet = sendCmdToRtl5450(nFd, data, 3);if(!bRet){printf("[%s][%d] send cmd <0x16,0x01,0x01> failed. Count [%d]\n",\__FUNCTION__,__LINE__,uCount);break;}uCount = 0;while(uCount++ < 350){usleep(1000);u8FeedBuf = 0x00;bRet = recvFeedbackFromRtl5450Sigle(nFd,&u8FeedBuf);if(bRet && u8FeedBuf == 0x01){bStep5_2 = MAPI_TRUE;break;}else{continue;}}} while (0);

7. 重啟flash

do{MAPI_U8 data[5] = {0x05,0x03,0xDA,0x0B,0x01};MAPI_BOOL bRet = MAPI_FALSE;bRet = sendCmdToRtl5450(nFd, data, 5);if(!bRet){printf("[%s][%d] send cmd <0x05,0x03,0xDA,0x0B,0x01> failed. Count [%d]\n",\__FUNCTION__,__LINE__,uCount);break;}uCount = 0;while(uCount++ < 350){usleep(1000);u8FeedBuf = 0x00;bRet = recvFeedbackFromRtl5450Sigle(nFd,&u8FeedBuf);if(bRet && u8FeedBuf == 0x01){bStep6 = MAPI_TRUE;break;}else{continue;}}} while (0);

至此，整個(gè)升級流程完成。

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