Date: Wed, 25 Jan 2012 15:28:38 -0700 From: Warner Losh <imp@bsdimp.com> To: Marius Strobl <marius@alchemy.franken.de> Cc: Stefan Bethke <stb@lassitu.de>, FreeBSD-arch <freebsd-arch@freebsd.org> Subject: Re: Extending sys/dev/mii Message-ID: <EA39C477-1B2D-4CE4-B146-4D2E16603170@bsdimp.com> In-Reply-To: <20120125221753.GA17821@alchemy.franken.de> References: <47ABA638-7E08-4350-A03C-3D4A23BF2D7E@lassitu.de> <1763C3FF-1EA0-4DC0-891D-63816EBF4A04@lassitu.de> <20120106182756.GA88161@alchemy.franken.de> <95372FB3-406F-46C2-8684-4FDB672D9FCF@lassitu.de> <20120106214741.GB88161@alchemy.franken.de> <F60B2B70-049F-4497-BBA8-3C421088C1EA@lassitu.de> <20120108130039.GG88161@alchemy.franken.de> <23477898-8D85-498C-8E30-192810BD68A8@lassitu.de> <20120111193738.GB44286@alchemy.franken.de> <66DDA0A2-F878-43FF-8824-54868F493B18@lassitu.de> <20120125221753.GA17821@alchemy.franken.de>
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On Jan 25, 2012, at 3:17 PM, Marius Strobl wrote: > Yes, architecture of newbus is built around the assumption that > there's a single device tree and all you ever need are child- > parent-relationships. AFAICT this assumption dates back to at > least the device configuration in 4.4BSD and apart from the > embedded world it held true just fine so far ... Even in the embedded world it is true. The problem is that in the = embedded world multiple devices use the service of another device which = is why we're seeing teething pain with the MDIO bus (which shares all = the management lines between the PHY rather than having each MAC have = its own connection to the PHY). So while the basic resources are still = hierarchical, the interconnects have become more complicated. The issue = we're facing here is that we'd assumed that the MAC PHY connection could = provide management services since you knew you had to have data services = or else you'd have no packet flow... We're seeing the same struggles with gpio and interrupt pins... Warner
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