精品文檔-下載后可編輯s3c2410的nandflash的驅(qū)動分析-基礎(chǔ)電子以前都是把別人寫好的代碼直接拿過來用，而沒有去關(guān)心里面到底怎么實現(xiàn)的，昨晚對照著samsung2410和k9f1208的芯片資料把這些代碼讀了一遍，終于明白了對nandflash的操作一步步是怎么實現(xiàn)的了。以下的這些代碼可以在vivi或者kernel里面找到對一個nandflash的操作，總體上可以分為這么四步：一、SelecttheNANDdevice二、SendcommandtoNANDdevice三、OperATION四、De-selecttheNANDdevice下面是以上四步的實現(xiàn)代碼：一、SelecttheNANDdevice#definenand_select()this-hwcontrol(NAND_CTL_SETNCE);\nand_command(mtd,NAND_CMD_RESET,-1,-1);\udelay(10);hwcontrol(NAND_CTL_SETNCE)的作用是設(shè)置2410的NANDFLASHCONFIGURATION(NFCONF)REGISTER的NANDFlashMemorychipenable位為0，具體請參考samsung2410datasheet。NANDFlashMemorychipenable[11]NANDflashmemorynFCEcontrol0:NANDflashnFCE=L(active)1:NANDflashnFCE=H(inactive)(Afterauto-boot,nFCEwillbeinactive.)nand_command(mtd,NAND_CMD_RESET,-1,-1)；看字面意思都知道是resetnanddevice，具體實現(xiàn)請看下面。二、SendcommandtoNANDdevice這步又主要有以下幾個過程1、Begincommandlatchcycle實現(xiàn)代碼：this-hwcontrol(NAND_CTL_SETCLE);//setcommandlatchenablethis-hwcontrol(NAND_CTL_DAT_OUT);//這個我還不清楚2、Writeoutthecommandtothedevice實現(xiàn)代碼：this-write_cmd(command);//writethecommandtoNANDFLASHCOMMANDSET(NFCMD)REGISTER3、SetALEandclearCLEtostartaddrESScycle實現(xiàn)代碼：this-hwcontrol(NAND_CTL_CLRCLE);//clearthecommandlatchenablthis-hwcontrol(NAND_CTL_SETALE);//settheaddresslatchenable4、Seriallyinputaddress實現(xiàn)代碼：this-write_addr(address);//writetheaddresstoNANDFLASHADDRESSSET(NFADDR)REGISTER5、Latchinaddress實現(xiàn)代碼：this-hwcontrol(NAND_CTL_CLRALE);//cleartheaddresslatchenablethis-hwcontrol(NAND_CTL_DAT_IN);//這個我也不清楚6、Pausefor？us實現(xiàn)代碼：udelay(?)//延時，總得給NandFlash一點反應(yīng)時間三//時間視具體NandFlash而定三、Operation主要是往NANDFLASHDATA(NFDATA)REGISTER里面寫或者讀數(shù)據(jù)例如：staticu_charread_data(void){return(u_char)NFDATA;}四、De-selecttheNANDdevice實現(xiàn)代碼：#definenand_deselect()this-hwcontrol(NAND_CTL_CLRNCE);跟selecttheNANDdevice相反，把NANDFLASHCONFIGURATION(NFCONF)REGISTER的NANDFlashMemorychipenable位置1至此，對samsung2410平臺上的NandFlash一個操作完成。以上是偶的個人理解，有啥不正確的地方還請大家指出來，感謝。下面是一個我還沒搞明白的問題，希望看到的朋友能指點下：這段代碼來自mizi_linux\drivers\mtd\nand\smc_s3c2410.cstaticvoidsmc_hwcontrol(intcmd){switch(cmd){caseNAND_CTL_SETNCE:NFCONF=~NFCONF_nFCE_HIGH;break;caseNAND_CTL_CLRNCE:NFCONF|=NFCONF_nFCE_HIGH;break;caseNAND_CTL_SETCLE:break;caseNAND_CTL_CLRCLE:break;caseNAND_CTL_SETALE:break;caseNAND_CTL_CLRALE:break;caseNAND_CTL_DAT_IN:break;ca