动态内存映射

ioremap_nocache

#define HOTPLUSPIN_MUX_REG  (0x120F0104)void __iomem *muxctrl_reg_va;static signed int GPIO_HOTPLUG = HIGPIO(5,3);int hotPlugPinInit(){    /**     *     *管脚复用值的修改放在pinmux.sh中修改     **/    muxctrl_reg_va = ioremap_nocache((unsigned long)HOTPLUSPIN_MUX_REG, (unsigned long)0x04);    if (NULL == muxctrl_reg_va)    {        printk(KERN_ERR "HOTPLUSPIN_MUX_REG function %s line %u failed\n",             __FUNCTION__, __LINE__);        return -1;    }    writel(0, muxctrl_reg_va);     _higpio_direction_output(GPIO_HOTPLUG,1);}

驱动卸载时要配合iounmap

iounmap(muxctrl_reg_va);