I'm doing kernel porting to arm926 based FPGA board (similar to samsung-s3c6410 board). I'm trying to setup UART for early print and console. I gone through some reference boards(samsung-s3c6410) for setting up uart for early print & console. I can't trace the virtual mapping for UART registers in "adduart" macro in "debug-macro.S" file .macro addruart, rp, rv ldr \rp, = S3C_PA_UART ldr \rv, = S3C_VA_UART Basically,I want to know how to calculate this virtual address(S3C_VA_UART) from the physical address(S3C_PA_UART) Below are the details #define PLAT_PHYS_OFFSET 0x50000000 (with 256 MB SDRAM) #define CONFIG_PAGE_OFFSET 0xc0000000 #define S3C_ADDR_BASE 0xF6000000 (virtual address for device registers) #define S3C_VA_UART (S3C_ADDR_BASE + (0x01000000) ) #define S3C_PA_UART 0x7F005000 (UART - Physical address) #define S3C_VA_UART 0xF7000000 (UART virtual address = 0xF6000000 + 0x01000000) I tried to calculate the virtual address by using " __phys_to_virt(x)" macro. #define __phys_to_virt(x) ((x) - PHYS_OFFSET + PAGE_OFFSET) from the above macro, I expect __phys_to_virt(S3C_PA_UART) = S3C_VA_UART = 0xF7000000 but if i do calc, 0x7F005000 - 0x50000000 + 0xc0000000 = 0xef005000 which is not correct. I think, i'm not using the correct macro for getting the virtual address for UART. can someone suggest how to do this calculation for getting proper virtual address for UART for the above configuration. Thanks, pcuser