From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from majordomo by infradead.org with local (Exim 3.16 #2) id 142Evv-0006GO-00 for mtd-list@infradead.org; Sat, 02 Dec 2000 15:50:39 +0000 Received: from laxmls02.socal.rr.com ([24.30.163.11]) by infradead.org with esmtp (Exim 3.16 #2) id 142Evt-0006GI-00 for mtd@infradead.org; Sat, 02 Dec 2000 15:50:38 +0000 Date: Sat, 2 Dec 2000 08:54:19 +0000 From: Shane Nay To: Nicolas Pitre Cc: Shane Nay , mtd@infradead.org Subject: Re: Problems with cfi_cmdset_0001 Message-ID: <20001202085419.I4457@www.easysolutions.net> References: <20001202050132.B4457@www.easysolutions.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit In-Reply-To: ; from nico@cam.org on Sat, Dec 02, 2000 at 15:23:33 +0000 Sender: owner-mtd@infradead.org List-ID: 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. To unsubscribe, send "unsubscribe mtd" to majordomo@infradead.org