Date: Wed, 16 Dec 2015 02:55:00 +0100 From: Marius Strobl <marius@alchemy.franken.de> To: Andrew Turner <andrew@fubar.geek.nz> Cc: freebsd-sparc64@FreeBSD.org, freebsd-ppc@FreeBSD.org Subject: Re: Testing an Open Firmware interrupt-map patch Message-ID: <20151216015500.GA70379@alchemy.franken.de> In-Reply-To: <20151215002830.2531673d@zapp> References: <20151214134625.79283652@zapp> <20151214234710.GA32903@alchemy.franken.de> <20151215002830.2531673d@zapp>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, Dec 15, 2015 at 12:28:30AM +0000, Andrew Turner wrote: > On Tue, 15 Dec 2015 00:47:10 +0100 > Marius Strobl <marius@alchemy.franken.de> wrote: > > > On Mon, Dec 14, 2015 at 01:46:25PM +0000, Andrew Turner wrote: > > > Hello, > > > > > > I'm looking for testers for a patch to update how we parse the > > > interrupt-map property to follow the ePAPR spec. This property is > > > commonly used with PCIe controllers. > > > > > > The current code doesn't take the parent address size property. When > > > this is non-zero we need to also read these values. This is needed > > > on an arm64 board I have as the interrupt parent has memory-mapped > > > children so needs this to be set. > > > > > > I have a patch at [1] to add this, however would like it if this > > > could be tested on other platforms using this code to check it > > > doesn't break these platforms before I commit it. > > > > + "#address-cells", &paddrsz, sizeof(paddrsz)) == > > -1) > > + paddrsz = 0; /* default */ > > > > According to IEEE 1275-1994 (page 110) the default in case of a > > "#address-cells" property is 2 (see also ofw_bus_setup_iinfo()), > > with the latter also being known as the correct default value > > for sparc64 machines. > > However both Linux and NetBSD have similar code, both assume a missing > interrupt-parent #address-size property the correct value is 0. According to ePAPR v1.1, the default in case of missing "#address-cells" properties also is 2 (page 24). However, it also says that the open-pic node/parent interrupt domain has an "#address-cells" value of 0 (page 36). So the above snippet appears more like a workaround for broken device trees as far as ePAPR is concerned, at least the comment "default" is misleading in that regard. > > In any case, this will have quite an impact on the offset > > calculation on sparc64 machines for e. g. EBusses beneath PCI > > busses (which use 3 address cells there) and, thus, most likely > > will cause havoc. Maybe the parent unit address should be only > > taken into account on platforms using interrupt parents? > > It would seem there is a difference between the encoding on Sparc64 and > ePAPR. Using the the parent #address-size may lead to incorrect parsing > on Sparc64, as such I will disable it there. > Yes, as the name suggests, ePAPR is a specification for the Power Architecture. Originally, ofw_bus_search_intrmap() also was sparc64 MD code until nwhitehorn@ in r186128 brought it over to the truly MI sys/dev/ofw/ofw_bus_subr.c I had started. Actually, as for the parent unit address in the interrupt map table ePAPR v1.1 specifically refers to the interrupt parent (page 34). So in order to avoid an #if !defined(__sparc64__) in MI code it seems best to do what I suggested above and to apply paddrsz only on the platforms that actually use interrupt parents. Alternatively, please at least invert it to an #if defined(OFW_EPAPR) and define OFW_EPAPR in sys/<arch>/include/ofw_machdep.h as applicable. Marius
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20151216015500.GA70379>