[U-Boot-Users] Extending bootm command.

[Steven Scholz]

Hi there,

from time to time it might be necessary to (decompress and) copy some data from
flash to ram.

The configuration data for an Altera ACEX 1K FPGA for instance is about 163KB.
The gzipped file (for a quite complex design) is only 54kB. So instead of
wasting three flash sectors one could store a gzipped and mkimage wrapped
version of the data in flash. If calling mkimage with the type STANDALONE like
[1] proposes one could then use "bootm" to decompress and copy these data to
ram. In order to call "fpga load" afterwards one need the location and the
resulting size of the data. That is why I suggest the following patch:

* Patch by Steven Scholz, 29 Sep 2003:
    - A second parameter for bootm overwrites the load address for
      "Standalone Application" images.
    - bootm sets environment variable "filesize" to the resulting data lenght
      for "Standalone Application" images when autostart is set to "no".

Then one could do something like

if bootm $fpgadata $some_free_ram ; then
	fpga load 0 $some_free_ram $filesize ;
fi

Cheers,

Steven

[1] https://www.denx.de/twiki/bin/view/DULG/HowCanILoadAndUncompressACompressedImage

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