__raw_writeb __raw_writel __raw_readb

#include <mach/ep93xx-regs.h>

static unsigned char __raw_readb(unsigned int ptr)
{
	return *((volatile unsigned char *)ptr);
}

static unsigned int __raw_readl(unsigned int ptr)
{
	return *((volatile unsigned int *)ptr);
}

static void __raw_writeb(unsigned char value, unsigned int ptr)
{
	*((volatile unsigned char *)ptr) = value;
}

static void __raw_writel(unsigned int value, unsigned int ptr)
{
	*((volatile unsigned int *)ptr) = value;
}

这个函数直接操作的是寄存器，或者内存地址。