Date: Fri, 04 Jan 2013 12:10:54 -0500 From: Nathan Whitehorn <nwhitehorn@freebsd.org> To: Andrew Turner <andrew@fubar.geek.nz> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, "Robert N. M. Watson" <rwatson@FreeBSD.org> Subject: Re: svn commit: r244899 - head/sys/mips/beri Message-ID: <50E70D1E.5060208@freebsd.org> In-Reply-To: <20130103100258.2e22763f@fubar.geek.nz> References: <201212311106.qBVB6chM016661@svn.freebsd.org> <20130102081746.5435db05@fubar.geek.nz> <D89C1409-9D10-4C09-BBF8-E00CC9B6A57A@FreeBSD.org> <20130102110856.7c280fd5@fubar.geek.nz> <0E1E1A5C-BB34-4B82-828F-6FEE770A6037@FreeBSD.org> <20130103100258.2e22763f@fubar.geek.nz>
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On 01/02/13 16:02, Andrew Turner wrote: > On Wed, 2 Jan 2013 11:01:27 +0000 > "Robert N. M. Watson" <rwatson@FreeBSD.org> wrote: > >> On 1 Jan 2013, at 22:08, Andrew Turner wrote: >> >>>> On a semi-related note: the current obstacle to moving more devices >>>> over to using FDT on BERI is that our FDT implementation appears to >>>> require a PIC to be configured. We're not actually using a PIC on >>>> BERI currently. It works fine attached to nexus, as the implied >>>> fallback for not having a PIC is to simply use the suitably >>>> numbered interrupt wires direct into the MIPS. However, trying the >>>> same setup described using FDT leads to an interrupt-related >>>> warning at boot, and no interrupt being provided to the driver. I >>>> suspect I need to provide a PIC-alike software component as a >>>> fall-back for the non-PIC case. From a brief e-mail exchange with >>>> JC, it sounds like the XLP FDT setup is actually not using >>>> interrupts either, currently. >>> I'm not sure if a PIC is required. From my reading of the code it >>> appears not. By the look of it if you are using the nexus to >>> handle interrupts you need to put an interrupts property in the >>> device and "#interrupt-cells = <1>;" in the soc node. >>> >>> You will also need to implement an interrupt decode function and >>> add it to the fdt_pic_table array. ARM has a number of almost >>> identical copies of this function you can use for inspration. >> >> This seemed to do the trick; what do you think of the attached? This >> isn't a board-specific change, so I dropped it into the common >> fdt_mips.c code. On the other hand, this left it a bit open as to >> what the right compatible= line to use was, so feedback there most >> welcome. > The patch looks good. From my reading of [1] the compatible value > should be something like "mips,mips4k" as it's value is of the form > "<manufacturer>,<model>". > > I have been thinking the best way of merging these almost identical > decode functions. Linux appears to do it by providing a per-controller > function that can translate between the interrupt spec and the > configuration allowing them to have a generic parsing function that > doesn't need to check if the controller is compatible. I would like us > to have something similar as it will remove the duplicate function. > > Andrew > > [1] http://www.devicetree.org/Device_Tree_Usage PowerPC does something very much like this currently in the real OF case. Looking at the contents of /sys/dev/fdt, it seems like there is a lot of code duplication in particular with interrupts and PCI handling compared to the equivalent parts of /sys/dev/ofw (and a few extra things that are actually MI like /sys/powerpc/ofw_pci*). It would be very nice if we could make FDT follow the normal OF codepaths instead of (partially) reinventing the wheel. -Nathan
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