S3C6410时钟初始化

　　void system_clock_init(void) { 	int count = 1000; 	(*(volatile unsigned int *)S3C6410_OTHERS_ADDR)	|= (1 << 6);	//sys clock select in cmu  	while(count--);	//nop 	(*(volatile unsigned int *)S3C6410_OTHERS_ADDR)	|= ((1 << 7) | (1 << 6));	//syncmodereq to arm,0:asynchronous mode 1:synchronous mode  	while((((*(volatile unsigned int *)S3C6410_OTHERS_ADDR) & 0xF00) != 0xF00));	//synchronous acknowledge  	writel(0xffff, S3C6410_APLL_LOCK);	//control pll locking period for apll 	writel(0xffff, S3C6410_MPLL_LOCK);	//control pll locking period for mpll 	writel(0xffff, S3C6410_EPLL_LOCK);	//control pll locking period for epll  	(*(volatile unsigned int *)S3C6410_CLOCK_DIV2) &= 0xFFF0FFFF;	 	(*(volatile unsigned int *)S3C6410_CLOCK_DIV2) |= (0x3 << 16);	//uart clock pider ratio,clkuart=clkuart_in/(uart_ratio+1)  	//0:3 p_arm clock pider ratio 	//4 p_mpll clock pider ratio 	//8 hclk clock pider ratio 	//9:11 hclkx2 clock pider ratio 	//12:15 pclk clock pider ratio,which must be odd value. in other words,s3c6410 supports only even pider ratio 	(*(volatile unsigned int *)S3C6410_CLOCK_DIV0) &= 0xFFFC0000;	 	(*(volatile unsigned int *)S3C6410_CLOCK_DIV0) |= ((0x3 << 12) | (1 << 9) | (1 << 8) | (1 << 4) | 0);	  	//0:2 sp,pll s pide value  	//8:13 pp,pll p pide value  	//16:25 pp,pll m pide value  	//31: pll enable control,0:disable 1:enable 	//f_out=mp*f_in(12MHZ)/(pp * (1 << sp)) 	writel(((1 << 31) | (266 << 16) | (3 << 8) | (1 << 0)), S3C6410_APLL_CON); 	writel(((1 << 31) | (266 << 16) | (3 << 8) | (1 << 0)), S3C6410_MPLL_CON);  	//0:2 sp, pll s pide value 0x3 	//8:13 pp, pll p pide value 0x2 	//16:23 mp, pll m pide value 0x20 	//31: pll enable control,0:disable 1:enable 	writel(0x80200203, S3C6410_EPLL_CON0);  	//0:15 kp,pll k pide value 	//f_out=(mp+kp/2^16)*f_in/(pp*2^sp)	24MHZ 	writel(0, S3C6410_EPLL_CON1);  	//0 control mux_apll,0:fin_apll 1:fout_apll 	//1 control mux_mpll,0:fin_mpll 1:fout_mpll 	//2 control mux_epll,0:fin_epll 1:fout_epll 	//13 control uart0,which is the source clock of uart,0:mout_epll 1:dout_mpll    	(*(volatile unsigned int *)(S3C6410_CLOCK_SRC)) |= (0x2007); 	 	count = 0x10000; 	while(count--);	//nop  	//(*(volatile unsigned int *)S3C6410_OTHERS_ADDR)	&= 0xFFFFFFDF;	 }