Date: Wed, 19 Mar 2014 08:06:11 -0700 From: Warner Losh <imp@bsdimp.com> To: Adrian Chadd <adrian@freebsd.org> Cc: "freebsd-embedded@freebsd.org" <freebsd-embedded@freebsd.org> Subject: Re: nand controller - how should one handle controllers that want the command+address bits together? Message-ID: <72D01ACF-F827-48E7-82DF-6728E5FC24EE@bsdimp.com> In-Reply-To: <CAJ-VmokZ4Xx4upMh7BSNJpHhoYCauqLW7xcZwhWVfvLvb6HSjw@mail.gmail.com> References: <CAJ-VmonpUsvXFHMCyH--3S4AEocTjhESCyjp9UmT-w5GyuZmvw@mail.gmail.com> <CAJ-VmomM=8M420-LC0z1CoZcz%2BjRBKx4n31ebtbfWG8_xF4Npw@mail.gmail.com> <5BF1217D-6423-443B-A3AB-1722CDDDAD74@bsdimp.com> <CAJ-VmokZ4Xx4upMh7BSNJpHhoYCauqLW7xcZwhWVfvLvb6HSjw@mail.gmail.com>
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On Mar 19, 2014, at 12:51 AM, Adrian Chadd <adrian@freebsd.org> wrote: > On 18 March 2014 07:12, Warner Losh <imp@bsdimp.com> wrote: >=20 >> Because the state machines needed for different NAND types more or >> less require the 'low level' interface that we have today. The = different >> phases in setting up a transaction vary somewhat between the = different >> types of NAND, and we have no real knowledge of that in the NAND = layer >> today. It was written 4 years ago when most controllers on the market >> did little more than bit-bang and/or module the signals to the NAND = since >> the interfaces at the time were little more than fancy memory mapped >> memory controllers. >=20 > Right. >=20 >=20 >> I've also been looking towards this area as well, given my recent >> NAND history. In fact, I've been putting together a talk for BSDcan >> on what needs to be done to make the NAND layer sane, cool and >> groovy. >=20 > I may have to come to bsdcan then. >=20 > You have a DB120; take a look at the ar934x-nfc.c code in openwrt and > see what they do. OK. > There's apparently a PIO mechanism. It's unclear how to use it and > honestly I wouldn't want to. I=92ll give it a look when I climb back into the NAND world here next = week or so (I was planning on being somewhat specific in my talk at BSDcan, so need to re-review my notes I=92ve taken so far). I=92ll see if I can get = you early access to my talk (meaning, I=92ll see if I can finish early :). Warner
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