Dear Ladislav Michl,
In message 20090428151147.GA19683@linux-mips.org you wrote:
a lot of changes are entering arm tree, many without any commit message. And now we have some special cases which needs some special care for yet unclear reason. OMAP3 timer precission was discussed to death and patch still didn't went in, because it needs to be verified against some document you are claiming is not mandatory.
Just in case there is any doubt here:
There is no, and I say *no*, mandatory verification of any timing precision in U-Boot.
We all agree that precision is a good thing to have, it it must come at a reasonable effort, and there is no reason to drive it into extreme precision.
Clock signals may need an accuracy of 1 or 2% or better - as we may see character corruption if the baudrate generators are off too far - but this is usually a hardware issue in the first place.
System timers (like udelay() etc.) in U-Boot do not need such a level of accuracy. That does not mean we should intentionally be inaccurate.
And of course actual testing is good, and documentation of the test results is even better.
But: it is not mandatory. Not in U-Boot (and also not in Linux, to the best of my knowledge).
I'll omit more comments to this topic until my objections get answered. Just one side note: Both methods can be easily set in code, freeing every and each developer from reimplementing test case. Such code could be one for all and selfexplaining. Is it worth doing using current timer API?
See my previuous posting. I don;t think that a generic test method that works on all boards would be possible.
Best regards,
Wolfgang Denk