[U-Boot-Users] PPC CLKIN

[Greg Davis]

We currently have several PQII and PQIII PrPMC boards that dynamically
support PCI bus speeds between 25 MHz and 133 MHz. These boards provide
a CPLD register that gives PCI frequency. I would like to take advantage
of this register, if possible, within u-boot rather than using a #define
such as CONFIG_83XX_CLKIN, CONFIG_8260_CLKIN, or CONFIG_SYS_CLK_FREQ for
the input clock frequency to the processor. Is there a suggested method
of doing this?

For testing I have implemented the following in get_sys_info() in
speed.c for an MPC8560 board:

#if !defined (CONFIG_SYS_CLK_FREQ)
	sysInfo->freqSystemBus = plat_ratio * get_sys_clk();
#else
	sysInfo->freqSystemBus = plat_ratio * CONFIG_SYS_CLK_FREQ;
#endif  

The get_sys_clk() function resides in the board code directory. Would
this be an acceptable method? It would minimize any impact to other
existing boards.
 
Greg