求问AR9344的SRIF相关信息和用法

http://lxr.free-electrons.com/source/arch/mips/include/asm/mach-ath79/ar71xx_regs.h#L536

找到SRIF的相关定义，还有一点解释：


http://patchwork.linux-mips.org/patch/4324/Besides the CPU and DDR PLLs, the CPU and DDR frequenciescan be derived from other PLLs in the SRIF block on theAR934x SoCs. The current code does not checks if the SRIFPLLs are used and this can lead to incorrectly calculatedCPU/DDR frequencies.

求问这个SRIF是个什么东东，哪里有相关参考信息和使用，我在AR9344的datasheet找了半天，没发现相关信息，求教，谢谢！