Issue in writing a data in PMU register

Hi,

Following are the query regarding the ARM Cortex A7 MP Core.

In ARM Cortex A7 MP Core,facing a issue in memory mapping the registers and accessing the registers by read and write operations.

By means of the reference manual the base configuration address has been read and set to the respective value.

I am not able to write the values by these assembly instruction " asm volatile("mcr p15, 0, %0, c9, c12, 0" : : "r"(0x07));" 0x07 is a data to be written to the PMU register.Even though the user enable register is set before writing the value to the register.

In the manual,the system control register holds a bit "WXN" [Write permission Execute Never] . According to my board,it was 0 (Regions with write permission are not forced to be XN, this is the reset value).Is this bit setting,blocks the write permissions to the other register?

Do i need to enable any register other than "PMUSERENR" before the write operation?

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