Re: [iPAQ] Cpu scaling ??

Jamey

Having taken my 3630 apart and obtained the part numbers of the sdram, 2
different parts. One Samsung and one I now understand to be Micron. (Thank
you Steve for that) I have managed to get the Micron data, but am unable to
find any data on the samsung site (this could be my browser setup, but I get
partway to the data sheets and then just get blank pages). Given that the
memory slots in my 3630 have one of each manufacturer then the performance of
the memory should be the same.

Here I have to make a number of assumptions which feel free to contest/modify:
1) add the necessary code to RMK's cpu-sa1110.c module;
2) assuming the calculations in there are valid, then provide the sdram
parameters as required for each module/build of the ipaq;
3) determine a sensible method of picking the correct sdram parameters at
runtime;
4) add the conditional compile and off we go!!!!
5) test the changes and submit to RMK? or handhelds.org? for inclusion.

2 above is at variance to the way Erik has done the sdram timings in
cpu-sa1100.c, but I think dynamic calculations make more sense if we are
going to have to deal with a number of sdram variants.

3 may not be an issue if the sdram timings are sufficiently similar for each
memory size, ie 32 and 64Mb. I think it would be incumbent on anyone
introducing a memory upgrade to provide the sdram timings and detection
method for future memory configurations.

From the Micron data I can extract the necessary parameters to populate an
initdata structure of the correct from in cpu-sa1110.c. I would like to look
at the 64Mb samsung data, so if anyone has a copy of the data, could they
please email it to me.

I note Erik's comment about continuing this on the linux-arm-kernel mailing
list, but I don't subscribe to that list (we all have to draw the line
somewhere about the number of lists we track:)) and given this is ipaq
specific I am happy to continue on here.

Regards

Bob
Received on Thu Jan 10 08:34:17 2002