Linux驱动操作地址(寄存器）的一些方式

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1.对绝对地址赋值操作

对绝对地址0x100000赋值操作

*（unsigned int *）0x100000=1234;

让程序跳转到绝对地址是0x100000去执行

*((void  (*) () )0x100000) ();

首先要将0x100000强制转换维函数指针，即：

(void  (*) () )0x100000

然后再调用它

*((void  (*) () )0x100000) ();

使用typedef可以更直观

typedef void(*) () voidFuncPtr;
*((voidFuncPtr)0x100000) ();

2. ioremap

2.1 void __iomem *地址

/* 寄存器物理地址 */
#define CCM_CCGR1_BASE              (0X020C406C)    
#define SW_MUX_GPIO1_IO03_BASE      (0X020E0068)
#define SW_PAD_GPIO1_IO03_BASE      (0X020E02F4)
#define GPIO1_DR_BASE               (0X0209C000)
#define GPIO1_GDIR_BASE             (0X0209C004)/* 映射后的寄存器虚拟地址指针 */
static void __iomem *IMX6U_CCM_CCGR1;
static void __iomem *SW_MUX_GPIO1_IO03;
static void __iomem *SW_PAD_GPIO1_IO03;
static void __iomem *GPIO1_DR;
static void __iomem *GPIO1_GDIR;

   /* 寄存器地址映射 */IMX6U_CCM_CCGR1 = ioremap(CCM_CCGR1_BASE, 4);SW_MUX_GPIO1_IO03 = ioremap(SW_MUX_GPIO1_IO03_BASE, 4);SW_PAD_GPIO1_IO03 = ioremap(SW_PAD_GPIO1_IO03_BASE, 4);GPIO1_DR = ioremap(GPIO1_DR_BASE, 4);GPIO1_GDIR = ioremap(GPIO1_GDIR_BASE, 4);

   int retvalue = 0;u32 val = 0;/*、使能GPIO1时钟 */val = readl(IMX6U_CCM_CCGR1);val &= ~(3 << 26);  /* 清楚以前的设置 */val |= (3 << 26);   /* 设置新值 */writel(val, IMX6U_CCM_CCGR1);/*设置GPIO1_IO03的复用功能，将其复用为*    GPIO1_IO03，最后设置IO属性。*/writel(5, SW_MUX_GPIO1_IO03);/*寄存器SW_PAD_GPIO1_IO03设置IO属性*bit 16:0 HYS关闭*bit [15:14]: 00 默认下拉*bit [13]: 0 kepper功能*bit [12]: 1 pull/keeper使能*bit [11]: 0 关闭开路输出*bit [7:6]: 10 速度100Mhz*bit [5:3]: 110 R0/6驱动能力*bit [0]: 0 低转换率*/writel(0x10B0, SW_PAD_GPIO1_IO03);/* 设置GPIO1_IO03为输出功能 */val = readl(GPIO1_GDIR);val &= ~(1 << 3);   /* 清除以前的设置 */val |= (1 << 3);    /* 设置为输出 */writel(val, GPIO1_GDIR);/* 默认关闭LED */val = readl(GPIO1_DR);val |= (1 << 3);    writel(val, GPIO1_DR);

2.2 volatile unsigned int *地址

static volatile unsigned int *CCM_CCGR1                       ;
static volatile unsigned int *IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03;
static volatile unsigned int *GPIO1_GDIR                      ;
static volatile unsigned int *GPIO1_DR                        ;

CCM_CCGR1                               = ioremap(0x20C406C, 4);
IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03        = ioremap(0x20E0068, 4);
GPIO1_GDIR                              = ioremap(0x0209C000 + 0x4, 4);
GPIO1_DR                                = ioremap(0x0209C000 + 0, 4);

/* GPIO1_IO03 */
/* a. 使能GPIO1* set CCM to enable GPIO1* CCM_CCGR1[CG13] 0x20C406C* bit[27:26] = 0b11*/
*CCM_CCGR1 |= (3<<26);/* b. 设置GPIO1_IO03用于GPIO* set IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03*      to configure GPIO1_IO03 as GPIO* IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03  0x20E0068* bit[3:0] = 0b0101 alt5*/
val = *IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03;
val &= ~(0xf);
val |= (5);
*IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03 = val;/* c. 设置GPIO1_IO03作为output引脚* set GPIO1_GDIR to configure GPIO1_IO03 as output* GPIO1_GDIR  0x0209C000 + 0x4* bit[3] = 0b1*/
*GPIO1_GDIR |= (1<<3);

2.3 struct+ioremap

struct iomux {volatile unsigned int unnames[23];volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO00; /* offset 0x5c */volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO01;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO02;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO04;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO05;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO06;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO07;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO08;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO09;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_UART1_TX_DATA;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_UART1_RX_DATA;volatile unsigned int IOMUXC_SW_MUX_CTL_PAD_UART1_CTS_B;
};struct imx6ull_gpio {volatile unsigned int dr;volatile unsigned int gdir;volatile unsigned int psr;volatile unsigned int icr1;volatile unsigned int icr2;volatile unsigned int imr;volatile unsigned int isr;volatile unsigned int edge_sel;
};/* enable GPIO4 */
static volatile unsigned int *CCM_CCGR3; /* enable GPIO5 */
static volatile unsigned int *CCM_CCGR1; /* set GPIO5_IO03 as GPIO */
static volatile unsigned int *IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER1;/* set GPIO4_IO14 as GPIO */
static volatile unsigned int *IOMUXC_SW_MUX_CTL_PAD_NAND_CE1_B;static struct iomux *iomux;static struct imx6ull_gpio *gpio4;
static struct imx6ull_gpio *gpio5;

CCM_CCGR1 = ioremap(0x20C406C, 4);
CCM_CCGR3 = ioremap(0x20C4074, 4);
IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER1 = ioremap(0x229000C, 4);
IOMUXC_SW_MUX_CTL_PAD_NAND_CE1_B        = ioremap(0x20E01B0, 4);iomux = ioremap(0x20e0000, sizeof(struct iomux));
gpio4 = ioremap(0x020A8000, sizeof(struct imx6ull_gpio));
gpio5 = ioremap(0x20AC000, sizeof(struct imx6ull_gpio));

       if (which == 0){/* 1. enable GPIO5 * CG15, b[31:30] = 0b11*/*CCM_CCGR1 |= (3<<30);/* 2. set GPIO5_IO03 as GPIO * MUX_MODE, b[3:0] = 0b101*/*IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER3 = 5;/* 3. set GPIO5_IO03 as output * GPIO5 GDIR, b[3] = 0b1*/gpio5->gdir |= (1<<3);}else if(which == 1){/* 1. enable GPIO1 * CG13, b[27:26] = 0b11*/*CCM_CCGR1 |= (3<<26);/* 2. set GPIO1_IO03 as GPIO * MUX_MODE, b[3:0] = 0b101*/iomux->IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03 = 5;/* 3. set GPIO1_IO03 as output * GPIO1 GDIR, b[3] = 0b1*/gpio1->gdir |= (1<<3);}else if(which == 2){/* 1. enable GPIO1 * CG13, b[27:26] = 0b11*/*CCM_CCGR1 |= (3<<26);/* 2. set GPIO1_IO05 as GPIO * MUX_MODE, b[3:0] = 0b101*/iomux->IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO05 = 5;/* 3. set GPIO1_IO05 as output * GPIO1 GDIR, b[5] = 0b1*/gpio1->gdir |= (1<<5);}else if(which == 3){/* 1. enable GPIO1 * CG13, b[27:26] = 0b11*/*CCM_CCGR1 |= (3<<26);/* 2. set GPIO1_IO06 as GPIO * MUX_MODE, b[3:0] = 0b101*/iomux->IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO06 = 5;/* 3. set GPIO1_IO06 as output * GPIO1 GDIR, b[6] = 0b1*/gpio1->gdir |= (1<<6);}if (which == 0){/* 1. enable GPIO5 * CG15, b[31:30] = 0b11*/*CCM_CCGR1 |= (3<<30);/* 2. set GPIO5_IO01 as GPIO * MUX_MODE, b[3:0] = 0b101*/*IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER1 = 5;/* 3. set GPIO5_IO01 as input * GPIO5 GDIR, b[1] = 0b0*/gpio5->gdir &= ~(1<<1);}else if(which == 1){/* 1. enable GPIO4 * CG6, b[13:12] = 0b11*/*CCM_CCGR3 |= (3<<12);/* 2. set GPIO4_IO14 as GPIO * MUX_MODE, b[3:0] = 0b101*/IOMUXC_SW_MUX_CTL_PAD_NAND_CE1_B = 5;/* 3. set GPIO4_IO14 as input * GPIO4 GDIR, b[14] = 0b0*/gpio4->gdir &= ~(1<<14);}