教程成果freescale i.mx28boot-stream分析

快速啟 通用連 支 全球到 7 供電電壓： 5V±級 0– -40–85 10–90%（不結(jié)露 OEM、ODM Android技術(shù)支持 L2Switch，CAN6UART，便于工控產(chǎn)品系linux議、基礎(chǔ)庫、應(yīng)用程序框架和應(yīng)用程序支撐層。無需熟悉底層繁瑣的基礎(chǔ)性，linuxAPI，只需要會C++即可設(shè)計出完美的客戶應(yīng)用程序。工業(yè)級和汽車級環(huán)境，寬溫度范圍，高穩(wěn)定性，非常適合于工業(yè)控制、、醫(yī)療器械、儀器儀表碼。Linux_prepkernel，kernel(zImage)TCPIP網(wǎng)絡(luò)協(xié)議棧。i.MX28U-BootFEC以太網(wǎng)控制器內(nèi)置的驅(qū)動程序，可以使用TCP/IP網(wǎng)絡(luò)kernel.(NFS,TFTP)Bootstream啟動經(jīng)歷四個階段;這里直接IMX28USER'SGUIDE文檔的說明power_prep—Thisbootletconfiguresthepowerboot_prep—Thisbootletconfigurestheclocksandlinux_prep—Thisbootletpreparestoboot {.= .=.text:{*(.text).data:{*(.data).bss:{*(.bss) =號前的"."為地址計數(shù)器(locationcounter),該符號只能用于SECTIONS命令內(nèi)部，初始值為‘0’，可 //clearRTCALARMwakeuporAUTORESTARTbitsherehw_power_SetPowerClkGate(false); HW_POWER_VDDIOCTRL.B.LINREG_OFFSET=FIQ，可以參照i.MX28Datasheet在不同頻率時設(shè)置這個掉電/*VDDDVDDAVDDIOVDDD—providespowertothedigitalcomponentsofthei.MX28processor.TheusetheVDDDpowerVDDA—providespowerspecificallytotheaudiosystems,headphoneamp.TheVDDApowerrailalsoprovidespowertoregulatetheVDDMEMVDDIO—providespowertotheI/OperipheralsandalsototheNANDFlashandexternalSecureDigital/MultiMediaCards//但是電池需要開發(fā)板的支持，IMX28EVK ddi_power_SetVddio(3300,ddi_power_SetVddd(1350,VDDIOVDDDbrownoutlevel。BM_POWER_CTRL_VDDD_BO_IRQ|BM_POWER_CTRL_VDDA_BO_IRQ|BM_POWER_CTRL_VDDIO_BO_IRQ|BM_POWER_CTRL_VDD5V_DROOP_IRQ|BM_POWER_CTRL_VBUSVALID_IRQ|BM_POWER_CTRL_BATT_BO_IRQ|if(!bBatteryReady)returniRtn; {.= .=.text:{*(.text).data:{*(.data).bss:{*(.bss) link.lds和powe_prep下的link.lds一樣，毫無壓力，懂得。代碼到此將進(jìn)入boot_prep的_start()這里測試RAM的方法很簡單，volatileint*pTest= 向 CPU寄存器的設(shè)置必須滿足下面的條件：stmdbsp!,{r4-r12,/*Checkentrycounter*/ldrr4,entry_countcmpr4,bne>bl/*Updatecountertoshowwewerehere*/addr4,r4,#1strr4,/*ReturntoROM*/ldmiasp!,{r4-r12,lr}bxlrblclear_bss/*InitializeHWmodulesrelevantforlinux_prep*/blhw_init/*SetuptagsforLinuxkernelandsavetagspointerinr2blmovr2,//R2里面保持了內(nèi)核啟動參數(shù)的地址,r0里 /*Storemachineidinr1*/ldrr1,=MACHINE_ID//其實(shí)就是個數(shù)字 MACHINE_ID/*Zeror0register*/movr0,#0/*JumptoLinuxkernel*/ldrlr,=KERNEL_BASE_ADDRESSmovpc,//如果從休眠狀態(tài)啟動內(nèi)核，就跳到try_to_resumeu32u32setup_tags{enummagic_keymagic_key;magic_key=get_magic_key();return}staticstaticvoidsetup_start_tag(bd_t{params->hdr.tag=ATAG_CORE;params->u.core.flags=0;params->u.core.pagesize=params=tag_next(params);}staticstaticvoidsetup_memory_tags(bd_t{params->hdr.tag=params->u.mem.start=SDRAM_BASE;params->u.mem.size=get_sdram_size();params=}}函數(shù)設(shè)置了一個(3)setup_initrd_tagstaticstaticvoid{params->hdr.tag=ATAG_INITRD2;params->u.initrd.start=;params->u.initrd.size=;params=}設(shè)置了ramdiskimagestaticstaticvoidsetup_end_tag(bd_t{params->hdr.tag=ATAG_NONE;params->hdr.size=0;}ldrldrlr,movpc,IMX28-EVK編譯直接啟動linux這種方法需要將生產(chǎn)的zImage鏡像制成imx28_linux.sb鏡像imx28_linux.sbzImage鏡像做了些加工，為zImage的運(yùn)行準(zhǔn)備環(huán)境。章 scaleImx28開發(fā)環(huán)境的搭建#mkdir#mkdirboot-#cdboot-#sudotarxvfz # elftosb2-z-c./linux_prebuilt.db-oi