UART's register read/write

JamesLeung — Thu, 29 Oct 2020 08:49:09 GMT

Hi i.mx experts,

I am trying create a hardware driver module for linux kernel. The hardware is connecting to the i.mx28 through UART, therefore I am trying to access the UART register directly through iowrite(). However I found that I can never write to the register address. Below is code I am using:

release_mem_region(UARTBASE_PA, 145);

if(request_mem_region(UARTBASE_PA, 145, "myserial") ==NULL){

 printk("iomem request refused\n");

} else

 UARTBASE =(u32) ioremap_nocache((u32) UARTBASE_PA, 145);

iowrite32((u32) 0x100,(u32) (UARTBASE+0x20));

x=ioread32(UARTBASE+0x20);

printk("%x\ \n", x);

Where the ioread() output always is the default value instead of the one I write to it.

I have no idea how to solve this problem, please help, any idea will be helpful.

Thank you in advance!

James

i.MX Processors中的主题 UART's register read/write

UART's register read/write