[U-Boot-Users] main clock calculation invalid

[Junior]

> -----Original Message-----
> From: wd at denx.de
> Sent: Thu, 19 Apr 2007 17:54:59 +0200
> To: ejr at inbox.com
> Subject: Re: [U-Boot-Users] main clock calculation invalid
> 
> In message <06D6E1270E8.0000028Aejr at inbox.com> you wrote:
>> 
>> I'm trying to figure out why the below calculation of my main frequencey
>> clock is not correct.
>> 
>> In the below equation:
>> maindiv2 = 28
>> maindiv1 = 13
>> prediv = 23
>> ps = 0
>> and CONFIG_SYS_CLK_FREQ is 14745600.
> 
> I'm sorry, but the user's manual for my Z80 processor does not contain
> any part which matches your description.
> 
> What might be missing?

I'm not sure what you're missing but my emphasis was on the calculation. 
This is on an ARM9 LH7A404 chip. Now I might be missing something but even on a 16 bit CPU
the calculation result shouldn't change, no?

This is the function, all my printed values are correct before the calculation.

/* return FCLK frequency */
ulong get_FCLK (void)
{
    lh7a40x_csc_t* csc = LH7A404_CSC_PTR;
    ulong maindiv1, maindiv2, prediv, ps;

    /*
     * FCLK = ((MAINDIV1 +2) * (MAINDIV2 +2) * 14.7456MHz) /
     *                   ((PREDIV+2) * (2^PS))
     */
    maindiv2 = (csc->clkset & CLKSET_MAINDIV2) >> 11;
    maindiv1 = (csc->clkset & CLKSET_MAINDIV1) >> 7;
    prediv = (csc->clkset & CLKSET_PREDIV) >> 2;
    ps = (csc->clkset & CLKSET_PS) >> 16;
    printf("maindiv2: %d, maindiv1 %d, prediv %d, ps %d\n",maindiv2,maindiv1,prediv,ps);
    printf("CONFIG_SYS_CLK_FREQ: %d \n",CONFIG_SYS_CLK_FREQ);
    return ( ((maindiv2 + 2) * (maindiv1 + 2) * CONFIG_SYS_CLK_FREQ) / ((prediv + 2) * (1 << ps)));
}