Re: Problems with cfi_cmdset_0001

Shane Nay
2000-12-02T15:50:39Z

Nicholas,
> Please consider using the following for better efficiency instead:
>
> cmd_adr = addr & ~(mtd->erasesize-1);

Will do. I was trying to think of the bit wise way to do it, but I was/am
kind of tired.

>
> This produces the same result but omits the division which is best to
> avoid
> on some CPUs which don't have a native instruction for it.

Tell me about it..., working on FPU less MIPS processor. So division in
general makes the hair on my neck stand out on end.

>
> What kind of arrangement do the probe function find? Does it actually
> tell
> you: "Found 2 x8 CFI devices at location 0 in 8 bit mode"? If not,
> you'll
> have to look at the probe code in cfi-probe.c. Carefully reordering the
> probe sequence might be required (I had to do it for the 32-bit buswidth
> case).

Ah, ic. No, I think it found it correctly, here's the output: (Paste
isn't working right now, have to turn on Emulate3Buttons again)
supports x8 and x16 via BYTE# with asynchronous interface

>
> My impression is that it had better advantages to be separate just to
> keep
> things as simple as possible.

I happen to agree with your position now :-). After a couple days of
drudging through stuff, I think simple is much better :). I don't know
whether to contribut this stuff, and use a macro to re-probe for the
commandset_xip, and then write a commandset_xip.c file and contribute that
or what precisely. It's pretty special purpose, so maybe just a patch
floating around for people to try out. In any case, I have to maintain the
patch against linux-vr cvs repository for our device after we ship, so
it'll be floating around on the agenda computing pages starting Real Soon
Now, aka, as soon as I suck it into a kernel release for our device, which
is likely to be Monday or Tuesday.

> Well... I don't know who is the official maintainer, but I think I
> contributed the largest mods recently.

Cool, then I'll make the patch, post it on one of our pages and drop a link
here. You guys can choose to include it in your stuff or not. I
understand Daves philsophical issue on this..., RAM is cheaper than flash
:-).

Thanks,
Shane.