AM4378，地址映射方式进行io复用操作时，寄存器写不进去数值

只看该作者 · 2020-9-15 11:38

本帖最后由丑小鸭丶于 2020-9-15 11:43 编辑

如题：在进行IO复用操作，先对寄存器进行地址映射，然后往寄存器里面写数据，但是发现写入失败，跪求大佬帮忙看下。

具体步骤 & 现象：
1、先进行IO复用相关寄存器地址映射
2、将值写入寄存器
3、读取寄存器的值，还是原来的默认值

备注：
同样是寄存器地址映射，写入GPIO寄存器、和写入SPI寄存器的值就可以正常写入，只有复用寄存器写入不了。大致代码如下：
备注：代码发不进来，不知道为啥，将代码贴到评论区了。

复制

<blockquote> /* pin mux io map */

打印结果如下：

复制

<blockquote>----pin mux iomap start.--------

只看该作者 · 2020-9-15 11:41

本帖最后由丑小鸭丶于 2020-9-15 14:55 编辑

代码如下：（因为用的QNX操作系统的库，有些函数说明如下）
mmap_device_io()函数为：地址映射函数。
in32()函数为：将寄存器里面的数值读取出来。
out32()函数为：将外面的变量的数值写入到寄存器中去。
bit0、bit1这种赋值方式为位域操作，直接给变量的对应位赋值0/1。如spi_pin->my_conf_mcasp0_aclkx.value.bit.bit0 = 1;表示给bit0赋值为1。

代码：
一、寄存器定义代码：
/* GPIO MUX */
#define AM437X_PIN_MUX_SIZE                   0x1000
#define CONTROL_MODULE_BASE                0x44E10000
#define CTRL_CONF_MCASP0_ACLKX             ((CONTROL_MODULE_BASE) + (0x990))
#define CTRL_CONF_MCASP0_FSX                ((CONTROL_MODULE_BASE) + (0x994))
#define CTRL_CONF_MCASP0_AXR0                ((CONTROL_MODULE_BASE) + (0x998))

typedef struct {
am437x_reg my_conf_mcasp0_aclkx;
am437x_reg my_conf_mcasp0_fsx;
am437x_reg my_conf_mcasp0_axr0;
} am437x_pin_mux;

二、功能代码：
am437x_pin_mux *spi_pin

/* 引脚复用寄存器地址映射  pin mux io map */
DEBUG_INFO("----pin mux iomap start.-----------\r\n");
spi_pin->my_conf_mcasp0_aclkx.vaddr = mmap_device_io(AM437X_PIN_MUX_SIZE, CTRL_CONF_MCASP0_ACLKX);
spi_pin->my_conf_mcasp0_fsx.vaddr = mmap_device_io(AM437X_PIN_MUX_SIZE, CTRL_CONF_MCASP0_FSX);
spi_pin->my_conf_mcasp0_axr0.vaddr  = mmap_device_io(AM437X_PIN_MUX_SIZE, CTRL_CONF_MCASP0_AXR0);
if ((spi_pin->my_conf_mcasp0_aclkx.vaddr == (uintptr_t)MAP_FAILED) ||
      (spi_pin->my_conf_mcasp0_fsx.vaddr == (uintptr_t)MAP_FAILED) ||
      (spi_pin->my_conf_mcasp0_axr0.vaddr  == (uintptr_t)MAP_FAILED)) {
      printf("io map failed\r\n");
      return ;
}
DEBUG_INFO("----pin mux iomap end.  -----------\r\n");

/* spi对应引脚复用寄存器操作  pin mux */
/* 1. sclk引脚复用寄存器  spi1_sclk */
DEBUG_INFO("reg value = 0x%8x\r\n", in32(spi_pin->my_conf_mcasp0_aclkx.vaddr));

spi_pin->my_conf_mcasp0_aclkx.value.all = in32(spi_pin->my_conf_mcasp0_aclkx.vaddr);
spi_pin->my_conf_mcasp0_aclkx.value.bit.bit0 = 1;
spi_pin->my_conf_mcasp0_aclkx.value.bit.bit1 = 1;
spi_pin->my_conf_mcasp0_aclkx.value.bit.bit2 = 0;
spi_pin->my_conf_mcasp0_aclkx.value.bit.bit3 = 0;
out32(spi_pin->my_conf_mcasp0_aclkx.vaddr, spi_pin->my_conf_mcasp0_aclkx.value.all);

DEBUG_INFO("value    = 0x%8x\r\n", spi_pin->my_conf_mcasp0_aclkx.value.all);
DEBUG_INFO("reg value = 0x%8x\r\n", in32(spi_pin->my_conf_mcasp0_aclkx.vaddr));

/* 2. spi1_d0引脚复用寄存器 */
DEBUG_INFO("reg value = 0x%8x\r\n", in32(spi_pin->my_conf_mcasp0_fsx.vaddr));

spi_pin->my_conf_mcasp0_fsx.value.all = in32(spi_pin->my_conf_mcasp0_fsx.vaddr);
spi_pin->my_conf_mcasp0_fsx.value.bit.bit0 = 1;
spi_pin->my_conf_mcasp0_fsx.value.bit.bit1 = 1;
spi_pin->my_conf_mcasp0_fsx.value.bit.bit2 = 0;
spi_pin->my_conf_mcasp0_fsx.value.bit.bit3 = 0;
out32(spi_pin->my_conf_mcasp0_fsx.vaddr, spi_pin->my_conf_mcasp0_fsx.value.all);

DEBUG_INFO("value    = 0x%8x\r\n", spi_pin->my_conf_mcasp0_fsx.value.all);
DEBUG_INFO("reg value = 0x%8x\r\n", in32(spi_pin->my_conf_mcasp0_fsx.vaddr));

/* 3. spi1_d1 引脚复用寄存器 */
DEBUG_INFO("reg value = 0x%8x\r\n", in32(spi_pin->my_conf_mcasp0_axr0.vaddr));

spi_pin->my_conf_mcasp0_axr0.value.all = in32(spi_pin->my_conf_mcasp0_axr0.vaddr);
spi_pin->my_conf_mcasp0_axr0.value.bit.bit0 = 1;
spi_pin->my_conf_mcasp0_axr0.value.bit.bit1 = 1;
spi_pin->my_conf_mcasp0_axr0.value.bit.bit2 = 0;
spi_pin->my_conf_mcasp0_axr0.value.bit.bit3 = 0;
out32(spi_pin->my_conf_mcasp0_axr0.vaddr, spi_pin->my_conf_mcasp0_axr0.value.all);

DEBUG_INFO("value    = 0x%8x\r\n", spi_pin->my_conf_mcasp0_axr0.value.all);
DEBUG_INFO("reg value = 0x%8x\r\n", in32(spi_pin->my_conf_mcasp0_axr0.vaddr));

只看该作者 · 2020-9-15 11:42

本帖最后由丑小鸭丶于 2020-9-15 15:37 编辑

打印结果如下：
----pin mux iomap start.-----------
----pin mux iomap end.  -----------
reg value = 0x 8040007 //读取寄存器的初始值
value    = 0x 8040003 //要写入的寄存器的值
reg value = 0x 8040007  //读取寄存器的新值
reg value = 0x 8040007 //读取寄存器的初始值
value    = 0x 8040003 //要写入的寄存器的值
reg value = 0x 8040007  //读取寄存器的新值

reg value = 0x 8040007 //读取寄存器的初始值
value    = 0x 8040003 //要写入的寄存器的值
reg value = 0x 8040007  //读取寄存器的新值

只看该作者 · 2020-9-15 17:11

最新情况：手册中找到如下描述：
Note: For writing to the control module registers, the MPU will need to be in privileged mode of operation and writes will not work from user mode.

复用寄存器（控制寄存器）写不进去值，貌似是因为我处于用户模式，必须要切换到特权模式下才能写数据，那么如何切换到特权模式呢？

AM4378，地址映射方式进行io复用操作时，寄存器写不进去数值

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