[U-Boot-Users] waiting for timeouts in FPGA code?
Steven Scholz
steven.scholz at imc-berlin.de
Wed Feb 25 10:05:39 CET 2004
Wolfgang Denk wrote:
> In message <403B84DB.40900 at imc-berlin.de> you wrote:
>
>>in the U-Boot FPGA code timeouts are realized by
>>
>>if (get_timer (ts) > CFG_FPGA_WAIT{_INIT})
>> ...
>>
>>while CFG_FPGA_WAIT{_INIT} is supposed to be the timeout in milliseconds.
>
> Then this design is broken; get_timer() returns the number of timer
> ticks (= CFG_HZ per second). This is only milliseconds for CFG_HZ ==
> 1000.
So I does not matter how fast the timer ticks as long as CFG_HZ is set
to the correct value and timeouts are based on CFG_HZ. Correct?
>>This does not work for the AT91RM9200. Instead of using
>>
>>#define CFG_FPGA_WAIT 10
>>
>>I have to use
>>
>>#define CFG_FPGA_WAIT CFG_HZ/10
>
> Note that this is ten times as long as the original timeout.
Of course. Typo.
>>Is CFG_HZ defined for all other architectures?
> It is supposed to be defined. But many boards define it incorrectly.
>>Should we use CFG_HZ instead of hardcoded numbers?
> Definitely.
Hmm. But that means that when we change e.g. the above mentioned FPGA
code to use CFG_HZ that we might break these archictectures !?
--
Steven Scholz
imc Measurement & Control imc Meßsysteme GmbH
Voltastr. 5 Voltastr. 5
13355 Berlin 13355 Berlin
Germany Deutschland
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