[U-Boot] Imx6 u-boot clock frequency and wrong lpj in the kernel

Andy Ng andreas2025 at gmail.com
Sat Jan 31 00:58:24 CET 2015


Dear colleagues,

I faced a problem lately with the udelay function in the Linux kernel.
udelay uses loops_per_jiffy constant for its loops. lpj is calculated
during the init phase of the kernel, and then the calibrate  function is
removed. The boot loader uses 792MHz and when the kernel comes up dvfs
framework adjusts the  frequency to 1GHz, too late, and then the system
keeps using  lpj that was calculated at 792MHz.

Ideally we need to get the uboot to clock the imx6 at 1GHz. Is there any
special reason that u-boot does not pumps the clock up? Is there any patch
out there that enables u-boot to start at 1GHz?

Thank you
Andy


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