Date: Thu, 7 Jun 2007 22:05:06 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: Warner Losh <imp@bsdimp.com> Cc: arm@freebsd.org, bkoenig@alpha-tierchen.de, ticso@cicely.de Subject: Re: 4-bit SD Card mode Message-ID: <20070607200505.GO16463@cicely12.cicely.de> In-Reply-To: <20070607.133456.74668036.imp@bsdimp.com> References: <50392.2001:6f8:101e:0:20e:cff:fe6d:6adb.1181235257.squirrel@webmail.alpha-tierchen.de> <20070607180946.GK16463@cicely12.cicely.de> <49754.2001:6f8:101e:0:20e:cff:fe6d:6adb.1181244172.squirrel@webmail.alpha-tierchen.de> <20070607.133456.74668036.imp@bsdimp.com>
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On Thu, Jun 07, 2007 at 01:34:56PM -0600, Warner Losh wrote: > I'm not sure I like this at all. The devices shouldn't be setting up > the pins for that device. In some cases, they can't know how to do > that, and this is one of them. The device has no way of knowing if > all 4 wires are connected, or just 1 and the 'spare' lines are used > for GPIO. There are similar problems with the serial ports and the > ethernet. Absolutely - the MCI driver can't know the hardware. In fact it is routing the controller IO to pins, which is hardware related. > Does the boot loader you are using at least store the board ID in the > place that Linux expects it? Even then I don't really like this idea - at least not as a gerneral one. Many boards, including mine, have GPIO header, allowing the system integrator to use them for whatever they like. I don't see it sensible to introduce artificial different board-names for different uses. With the current system it is possible to have all drivers in the kernel and switch GPIO functionality even from userland. I don't see a good reason why the taskit board shouldn't get an updated firmware, which setups SD. FreeBSD even comes with source, which is able to do this in many cases. If it is really impossible, then this should at least be done in a board specific file and not spread into several drivers. -- B.Walter http://www.bwct.de http://www.fizon.de bernd@bwct.de info@bwct.de support@fizon.de
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