How to specify virtual Address for pl011 uart in linux kernel

Hi,

I am a beginner in kernel porting. I am trying to port Linux kernel (version- 4.9.22) on Custom SoC (cpu = arm1176jzfs based) for custom evaluation Board. I am having ARM Prime cell pl011 UART in my SoC. And it is physically mapped to 0x5800_1000 address. While i am trying to use it as Debug UART, kernel is asking for its virtual Address. How should i configure this option.

i.e:
    -> Kernel low-level debugging functions
        -> kernel low-level debugging port (Kernel low-level debugging on via ARM Ltd PL01x Primecell UART)
    (0x58001000) Physical base address of debug UART
    (??) Virtual base address of debug UART

Thanks,

Vivek T.

Parents
  • Vivek,

    The simple answer is that you don't need to provide it unless your platform calls iotable_init() manually (in which case you know what the virtual address is going to be ahead of time). If you're porting a 4.9 kernel you should not be doing this, so you can safely ignore it (the kernel will just move the console to whatever console=XXX argument or FDT stdout property points to at the appropriate time).

    Ta,

    Matt

Reply
  • Vivek,

    The simple answer is that you don't need to provide it unless your platform calls iotable_init() manually (in which case you know what the virtual address is going to be ahead of time). If you're porting a 4.9 kernel you should not be doing this, so you can safely ignore it (the kernel will just move the console to whatever console=XXX argument or FDT stdout property points to at the appropriate time).

    Ta,

    Matt

Children
More questions in this forum