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Benedict, Michael wrote:
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<pre wrap="">Hello,
I wrote a driver for a 4 segment digital display device. I have
a requirement that this device be used as early as possible to report
kernel bootup state. The driver itself is pretty simple, just using
in/out_be32() and udelay(). The problem is that I don't know how to use
hardware resources in the early stages of booting, before I can call
request_mem_region() and friends.
Can anyone recommend a book / documentation / reference code /
anything that demonstrates this, or at least could improve my
understanding enough to accomplish this?
</pre>
</blockquote>
u-boot for embedded (or OpenBios) documentation, source code. <br>
Look for splash screen code although you will want to make <br>
multiple calls for various boot states. In the ISA days and now<br>
PCI there are cards that display a two hex-digit POST progress <br>
code which is a single x86, 8bit output instruction to port 0x80.<br>
This may still be supported in closed source BIOS distributions.<br>
Not sure what they do now with PCIe since it will take more than<br>
a single, simple processor instruction.<br>
<br>
-Frank Bennett
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cite="mid:BAF8B1E0BB28024A90895E746A3B610D1C2F01@twx-exch01.twacs.local"
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<pre wrap=""> Many thanks,
Michael
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</pre>
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<br>
<br>
<div class="moz-signature">-- <br>
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<pre wrap=""><b><big><font face="Times New Roman, Times, serif"><em>Frank Bennett
President</em></font></big></b>
Mathegraphics,LLC
613 Bentley Pl
Fort Collins,CO 80526
970-229-9269 (hm) 970-402-9269 (cell)
<a href="http://www.mathegraphics.com">www.mathegraphics.com</a>
<span style="text-decoration: underline;"><a
href="mailto:bennett78@lpbroadband.net">bennett78@lpbroadband.net</a>
</span><small><font color="black" face="Courier New" size="2"><small><span
style="font-size: 10pt;">"I think there's a world market for about five computers."<o:p></o:p></span></small></font><font
color="black" face="Courier New" size="2"><small><span
style="font-size: 10pt;">
-- attr. Thomas J. Watson (Chairman of the Board, IBM), 1943<o:p></o:p></span></small></font><font
color="black" face="Courier New" size="2"><small><span
style="font-size: 10pt;"><o:p> </o:p></span></small></font><span
style="text-decoration: underline;">
</span></small></pre>
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