From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 213-239-205-147.clients.your-server.de ([213.239.205.147] helo=debian.tglx.de) by canuck.infradead.org with esmtp (Exim 4.42 #1 (Red Hat Linux)) id 1CEasy-0003Ly-J2 for linux-mtd@lists.infradead.org; Mon, 04 Oct 2004 18:00:50 -0400 From: Thomas Gleixner To: Nicolas Pouillon In-Reply-To: <20041004215001.769d8017.nipo@ssji.net> References: <20041004215001.769d8017.nipo@ssji.net> Content-Type: text/plain Message-Id: <1096926783.21297.535.camel@thomas> Mime-Version: 1.0 Date: Mon, 04 Oct 2004 23:53:03 +0200 Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org Subject: Re: [PATCH]Probing at 0x0 Reply-To: tglx@linutronix.de List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 2004-10-04 at 21:50, Nicolas Pouillon wrote: > I updated to last CVS snapshot. > After tweaking necessary declarations to interface with 2.6.7, I remade > some modifications in order to be able to probe at 0x0. > I made a patch for this (I hope that way is not too bad): > http://nipo.ssji.net/patches/mtd/nulladdress.diff Please add the patches to your mail. I'm not interested in collecting outdated http references. Providing patches by http reference makes sense for large modification which would either be rejected by the ML or annoying the majority of readers. > I still need to use readb and writeb, but this is not in the patch. WTF did say you should not use readb/writeb ? > This time, chip is probed as a DoC-Mil+ 32MB, driver complains about it > not being supported. It seems ok, and as mtd are much like rocket > science to me, I'll wait a little until it is (i hope) supported... It might be rocket science for you, but it still relies on simple straight forward facts. The DoC, which you pointed out, has Doc-chip-ID 0x41 according to the datasheet. from include/linux/mtd/doc2000.h #define DOC_ChipID_DocMilPlus32 0x40 #define DOC_ChipID_DocMilPlus16 0x41 So how is it identified as a Mil+32 ? Same magic as the NAND-ID is 0x85 instead of 0x75 ? Same quick solution, by adding some magic code / hope ? > I'll try to understand the mmio vs readb/writeb issue as a time > holder. ;) He, time holder. Did you mean placeholder ? It's neither nore. mmio is a technology. readb is a macro. writeb too. mmio == Memory Mapped Input Output. That means you have no seperate IO port instruction crap which was introduced by the worst CPU architecture on this planet. Everything, even your Line Printer Port is accessible in the memory space via a plain pointer without an extra IO-related instruction like outb/inb. see http://dri.sourceforge.net/cgi-bin/moin.cgi/MMIO and http://dri.sourceforge.net/cgi-bin/moin.cgi/PIO possibly http://www.c-for-dummies.com in any case see http://lxr.linux.no/ident?v=2.6.8.1;a=arm;i=readb where you can find out following the refrences that readb resolves at the end to (*(volatile unsigned char *)(a)) google for "volatile" yourself. Sorry for being cynical, but I'm too old to believe in IT-witchcrafts. tglx