實(shí)例解析：Uboot對(duì)非Linux kernel的引導(dǎo)

2024-06-28 13:04:03

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實(shí)現(xiàn)了uboot對(duì)非linux kernel的引導(dǎo)。雖然有一個(gè)IH_TYPE_STANDALONE，但是沒(méi)有實(shí)現(xiàn)。nnd。只能自己想辦法。實(shí)現(xiàn)詳細(xì)見(jiàn)下面。

1、兩個(gè)命令

set bootcmd tftp 84000000 uImage/;bootm 84000000

set bootdelay 1

2、非linux kernel的引導(dǎo)實(shí)現(xiàn)方法：

一共三個(gè)函數(shù)： jump，selectboot 和 system_boot

把jump放在需要跳轉(zhuǎn)的地方，參數(shù)就是要跳轉(zhuǎn)的地址。然后返回，重啟系統(tǒng)。select放在main的開(kāi)頭。通過(guò)判斷ram的特定地址的特定信息實(shí)現(xiàn)跳轉(zhuǎn)。

system_boot實(shí)現(xiàn)系統(tǒng)的重新啟動(dòng)

#define FDMA_SRAM_TOP_ADDRESS 0xB9229800#define MAGIC_NUM 0x71097100#define DEAD_PATTERN 0xBAD0BADF#define ST40_CPG_REGS_BASE 0xFFC00000#defineST40_CPG_WTCNT (ST40_CPG_REGS_BASE + 0x08)#define ST40_CPG_WTCSR (ST40_CPG_REGS_BASE + 0x0C)#define ST40_CPG_WTCSR2 (ST40_CPG_REGS_BASE + 0x1C)void Jump(unsigned int address){STSYS_WriteRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*1, MAGIC_NUM);STSYS_WriteRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*2, address);STSYS_WriteRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*3, ~address);STSYS_WriteRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*4, ~MAGIC_NUM); STSYS_WriteRegDev16LE(ST40_CPG_WTCNT, 0x5AF0); /*Watchdog counter*/STSYS_WriteRegDev16LE(ST40_CPG_WTCSR, 0xA547); /*Watchdog control*/STSYS_WriteRegDev16LE(ST40_CPG_WTCSR2, 0xAA00); /*Watchdog control2*/ STSYS_WriteRegDev16LE(ST40_CPG_WTCSR, 0xA5C7); /*Start watchdog counter*/ for(;;);}void SelectBoot(void){unsigned int MagicNum = 0;unsigned int NotMagicNum = 0;unsigned int JumpAddress = 0;unsigned int NotJumpAddress = 0; void (*entry)(void);/* entry=0xa0100000;entry();*/ //if((STSYS_ReadRegDev16LE(ST40_CPG_WTCSR2) & 0xFF) != 0x0){MagicNum = STSYS_ReadRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*1);JumpAddress = STSYS_ReadRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*2);NotJumpAddress = STSYS_ReadRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*3);NotMagicNum = STSYS_ReadRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*4); if((MagicNum == MAGIC_NUM)&& (MagicNum == (~NotMagicNum))&& (JumpAddress == (~NotJumpAddress))){entry = (void (*)(void))JumpAddress;STSYS_WriteRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*1, DEAD_PATTERN);STSYS_WriteRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*2, DEAD_PATTERN);STSYS_WriteRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*3, DEAD_PATTERN);STSYS_WriteRegDev32LE(FDMA_SRAM_TOP_ADDRESS - 4*4, DEAD_PATTERN); #if 0/*Setup For watchdog in case jump failed.*/STSYS_WriteRegDev16LE(ST40_CPG_WTCNT, 0x5AF0);STSYS_WriteRegDev16LE(ST40_CPG_WTCSR, 0xA543);STSYS_WriteRegDev16LE(ST40_CPG_WTCSR2, 0xAA01); STSYS_WriteRegDev16LE(ST40_CPG_WTCSR, 0xA5C7);#endif entry(); while(1);}}}void system_reboot(void){ulong sr;asm ("stc sr, %0":"=r" (sr));sr |= (1 << 28); /* set block bit */asm ("ldc %0, sr": :"r" (sr));asm volatile ("trapa #0");}

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