Writing to UART mapped memory address

Hello I am running trustzone Genode, with linux in normal world. I have made UART secure and I'm getting the fault address in DFAR register in dump in VM monitor. I want to write to a memory address which is mapped to UART i.e. physical address is in range [53FBC000, 53FFFFFF]. I am getting following error when I try to access the address:

``` no RM attachment (faulter 203128 with IP 7001e7d0 attempts to read from address 53fbc080) init -> tz_vmm -> vmm: unresolved pagefault at ip=7001e7d0 sp=e01fed10 fault address=53fbc080 core -> pager_ep: cannot submit unknown signal context ```

I'm using va_to_pa to get the physical address. I'm not sure how Genode maps the virtual addresses to I/O mapped physical region, or how can I write to UART mapped physical address?

Thanks Abhishek