[U-Boot] Flag -mno-cache-volatile to bypass the cache

[ivanchuklist ivanchu]

Hi list,
I use readl() or writel() to access the hardware but i found a compiler flag
that bypass the cache for all volatile variables, it uses io versions of
load/store functions. So, what should i do, make use of write/read functions
or insert this flag in the makefile?.
It's a nios2 platform. Thank you in advance.
Ivan Llopard.