Date: Fri, 04 Jul 2008 12:50:31 -0700 From: Marcel Moolenaar <xcllnt@mac.com> To: Takahashi Yoshihiro <nyan@jp.FreeBSD.org> Cc: ed@80386.nl, arch@freebsd.org, sam@freebsd.org, freebsd-current@freebsd.org Subject: Re: MPSAFE TTY schedule [uart vs sio] Message-ID: <29489C48-93A2-41D9-9EF1-5395A673A9B3@mac.com> In-Reply-To: <20080704.221043.226715262.nyan@jp.FreeBSD.org> References: <486D4006.2050303@freebsd.org> <993E865A-A426-4036-9E09-A87D7474DE80@mac.com> <20080704.063540.1210476607.imp@bsdimp.com> <20080704.221043.226715262.nyan@jp.FreeBSD.org>
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On Jul 4, 2008, at 6:10 AM, Takahashi Yoshihiro wrote: > In article <20080704.063540.1210476607.imp@bsdimp.com> > "M. Warner Losh" <imp@bsdimp.com> writes: > >> Do you need physical access? I have a pc98 machine I can put back on >> the network. It has the 8251 chip in it. It also has a 16550 part >> as >> well since it is a later model which had both... >> >> I believe that uart works for the 16550 part, but haven't tried it >> lately... > > The uart probably works for some 16550 based devices but does not work > for other one like multi-port devices. The design principle of uart(4) is that it does not know about multi-port hardware. It controls a single serial port only. For multi-port hardware you must have multiple nodes on a bus or use an umbrella driver, such as puc(4), quicc(4) or scc(4). Those drivers provide attachments for every port. I suspect that support for multi-port devices is not to hard to do on pc98... -- Marcel Moolenaar xcllnt@mac.com
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