count data memory access or I/O register access on OMAP4

Hi all, 

Is there any way to count data memory access or I/O register access on OMAP4?

My first thought was using performance counter. But unfortunately the PMU on OMAP4 can only count the number of LOAD/STORE instructions that are architecturally executed, which consists both data memory access and memory-mapped I/O access. But it can't distinguish them.

Is there any way to achieve this? Thank you.