[U-Boot-Users] Uncompression of image takes time.

Jerry Van Baren gerald.vanbaren at smiths-aerospace.com
Thu Mar 1 19:22:20 CET 2007

Adarsh Babu wrote:
> Jerry Van Baren <gerald.vanbaren <at> smiths-aerospace.com> writes:
>> Adarsh Babu wrote:
>>> Hi,
>>> I have an image which is 1.5MB in size after compression, thats is done 
> for 
>>> MCF5271. When i try to load this on a MCF5271 eval board using u-boot 
> 1.2.0 it 
>>> takes about 25 secs to just uncompress. I loaded a MCF5272 eval board with 
> U-
>>> Boot 1.2.0 and then tried to start the same image(which was done for 
> MCF5271). 
>>> It was very fast. The checksum verification finish off in a second and 
>>> uncompression in 10 seconds ! 
>>> The clock configurations for both are provided below:
>>> M5272C3.h
>>> define CFG_HZ			1000
>>> #define CFG_CLK			66000000
>>> M5271EVB.h:
>>> define CFG_HZ			1000000
>>> #define CFG_CLK			100000000
>>> What should I do to get the image to uncompress faster in the MCF5271 EVB?
>>> Regards,
>>> Adarsh.
>> 1) Your CFG_HZ looks like a problem: it should be 1000 and your timer 
>> tick interrupt should be running 1000 times per second to match.  If you 
>> are indeed ticking 1,000,000 times per second, you are spending all of 
>> your processor time in your timer ISR.
>> 2) Why is your image 1.5MB?  I suspect you have large unused areas of 
>> memory (typically due to ISR vectors, followed by a huge unused gap, 
>> followed by the code).  If you fix your image size (assuming it is 
>> broken), the checksum and uncompress will be much faster.
>> gvb
> Hi Jerry,
> I tried the same after modifying the CFG_HZ to 1000. But i still get the same 
> result. Its as if there is no effect. The image size is 1.5MB becos its just 
> not a kernel image. Its kernel + our application. Could this be a problem with 
> the timer initialization and cofiguration?
> Regards,
> Adarsh.

Hi Adarsh,

I don't have any M527x experience, so I cannot say anything with detail. 
  Just changing CFG_HZ quite likely is not sufficient - usually you need 
to configure the timers in your hardware initialization routines and 
CFG_HZ simply reflects the choices you (or someone) made at 
initialization time.

If this is the case, and if you timer is really ticking at 1/100 your 
master clock rate, that would cause serious slowing of execution.  You 
will have to chase down what CFG_HZ is used for and how your hardware 
timer is initialized.  I simply don't have the knowledge or information.


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