From: Segher Boessenkool <segher@kernel•crashing.org>
To: David Gibson <david@gibson•dropbear.id.au>
Cc: linuxppc-dev@ozlabs•org,
Yoder Stuart-B08248 <stuart.yoder@freescale•com>
Subject: Re: [PATCH 15/16] Add device tree for Ebony
Date: Thu, 15 Feb 2007 15:47:04 +0100 [thread overview]
Message-ID: <1ee5d4de0a640650826224f832374a67@kernel.crashing.org> (raw)
In-Reply-To: <20070215033328.GA17554@localhost.localdomain>
>> Yes true; you can hang the UICs from somewhere under the
>> "soc" node or whatever you want. You need some way to
>> distinguish separate identical devices though; you can't
>> do it by device unit since your devices don't have any
>> (they don't have a "reg" but only a "dcr-reg"). If you
>> would hang them in a DCR tree, you could use the plain
>> "reg" property instead of the "dcr-reg" property and
>> all would be fine (if the DCR binding allows this -- and
>> it better should, it is the standard OF addressing algorithm).
>
> No, doesn't work. The trouble is there are other devices that *do*
> sit on the normal MMIO bus, but also have DCRs (MAL, POB, SDRAM
> controller). The DCR tree has to cut across the normal bus tree, like
> the interrupt tree.
Yes, and they can use "dcr-reg" properties just fine; compare
to how "interrupt-parent" works: nodes that can use the normal
tree rules don't need it, everything else does.
>> However, my main point remains: the two interrupt controllers
>> should be siblings in the device tree, since they are that on
>> the hardware.
>
> In what way are they "that on the hardware". They're siblings on the
> DCR tree, they're parent/child on the interrupt tree. Given that
> they're not on the MMIO tree at all, I see no strong reason to pick
> one representation over another.
It's not about MMIO; it's about addressability. On many systems
almost none of the I/O subsystems primary address (config space
for PCI!) is on MMIO.
Quoting from OF1275:
> The device tree=92s structure mimics the organization of the system=20
> hardware, viewed as a hierarchy of interconnected buses and their=20
> attached devices.
The interrupt cascade is not a bus.
> I picked the interrupt tree, because
> it seemed to make as much or more logical sense as the other,
Yeah I know.
> and as a
> bonus it makes the probing logic easier.
How so? There already is completely generic probing
code for interrupt controllers AFAIK.
Segher
next prev parent reply other threads:[~2007-02-15 14:47 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-13 6:09 [0/16] Preliminary Ebony (440GP) support for arch/powerpc David Gibson
2007-02-13 6:10 ` [PATCH 3/16] [powerpc] Use udbg_early_init() on ppc32 David Gibson
2007-02-13 6:22 ` Benjamin Herrenschmidt
2007-02-13 6:10 ` [PATCH 7/16] Early serial debug support for PPC44x David Gibson
2007-02-13 15:04 ` Josh Boyer
2007-02-14 0:16 ` David Gibson
2007-02-14 1:02 ` Josh Boyer
2007-02-14 1:00 ` David Gibson
2007-02-14 2:00 ` Alan Modra
2007-02-14 2:02 ` David Gibson
2007-02-14 2:38 ` Alan Modra
2007-02-14 15:41 ` Josh Boyer
2007-02-14 23:05 ` David Gibson
2007-02-13 6:10 ` [PATCH 5/16] powerpc: Add zImage platform hook for kernel address David Gibson
2007-02-13 6:10 ` [PATCH 1/16] Remove ibm4{xx,4x}.h from arch/powerpc David Gibson
2007-02-13 14:19 ` Josh Boyer
2007-02-13 6:10 ` [PATCH 4/16] powerpc: Allow duplicate lmb_reserve() calls David Gibson
2007-02-13 7:05 ` Michael Neuling
2007-02-13 8:48 ` Michael Ellerman
2007-02-13 20:44 ` Benjamin Herrenschmidt
2007-02-13 6:10 ` [PATCH 2/16] More DCR native fixups David Gibson
2007-02-13 6:22 ` Benjamin Herrenschmidt
2007-02-13 6:10 ` [PATCH 6/16] Port 44x MMU definitions to ARCH=powerpc David Gibson
2007-02-13 6:24 ` Benjamin Herrenschmidt
2007-02-13 17:13 ` Roland Dreier
2007-02-13 17:45 ` Josh Boyer
2007-02-13 21:36 ` Benjamin Herrenschmidt
2007-02-13 6:10 ` [PATCH 8/16] Define FIXED_PORT flag for serial_core David Gibson
2007-02-13 6:10 ` [PATCH 12/16] Automatically lmb_reserve() initrd David Gibson
2007-02-13 7:14 ` Michael Neuling
2007-02-13 6:10 ` [PATCH 10/16] Add support for BSS stack for zImage wrapper David Gibson
2007-02-13 6:10 ` [PATCH 14/16] Add arch/powerpc driver for UIC, PPC4xx interrupt controller David Gibson
2007-02-13 6:10 ` [PATCH 11/16] zImage wrapper for Ebony David Gibson
2007-02-13 17:05 ` Geoff Levand
2007-02-14 0:17 ` David Gibson
2007-02-13 6:10 ` [PATCH 9/16] Use resource_size_t for serial port IO addresses David Gibson
2007-02-13 6:10 ` [PATCH 13/16] Add initrd properties to device tree from zImage David Gibson
2007-02-13 6:10 ` [PATCH 16/16] Support for Ebony in arch/powerpc David Gibson
2007-02-13 17:18 ` Roland Dreier
2007-02-14 0:20 ` David Gibson
2007-02-13 6:10 ` [PATCH 15/16] Add device tree for Ebony David Gibson
2007-02-13 20:08 ` Segher Boessenkool
2007-02-14 0:22 ` David Gibson
2007-02-14 1:51 ` Benjamin Herrenschmidt
2007-02-14 4:46 ` David Gibson
2007-02-14 17:54 ` Segher Boessenkool
2007-02-14 23:18 ` David Gibson
2007-02-15 0:25 ` Segher Boessenkool
2007-02-14 17:51 ` Segher Boessenkool
2007-02-14 17:48 ` Segher Boessenkool
2007-02-14 21:30 ` Benjamin Herrenschmidt
2007-02-15 0:03 ` Segher Boessenkool
2007-02-15 0:53 ` Benjamin Herrenschmidt
2007-02-15 1:00 ` Segher Boessenkool
2007-02-15 2:22 ` Benjamin Herrenschmidt
2007-02-15 2:51 ` Segher Boessenkool
2007-02-14 23:17 ` David Gibson
2007-02-15 0:27 ` Segher Boessenkool
2007-02-15 14:02 ` Jon Loeliger
2007-02-15 14:56 ` Segher Boessenkool
2007-02-15 17:02 ` Yoder Stuart-B08248
2007-02-15 17:10 ` Scott Wood
2007-02-16 9:20 ` Segher Boessenkool
2007-02-14 16:14 ` Yoder Stuart-B08248
2007-02-14 16:32 ` Josh Boyer
2007-02-14 17:58 ` Segher Boessenkool
2007-02-14 20:08 ` Yoder Stuart-B08248
2007-02-14 21:12 ` Segher Boessenkool
2007-02-14 21:35 ` Yoder Stuart-B08248
2007-02-14 21:42 ` Benjamin Herrenschmidt
2007-02-14 21:59 ` Scott Wood
2007-02-15 0:20 ` Segher Boessenkool
2007-02-14 22:50 ` Yoder Stuart-B08248
2007-02-14 22:57 ` Benjamin Herrenschmidt
2007-02-15 0:17 ` Segher Boessenkool
2007-02-15 2:12 ` Paul Mackerras
2007-02-15 2:43 ` Segher Boessenkool
2007-02-15 3:15 ` Paul Mackerras
2007-02-15 14:40 ` Segher Boessenkool
2007-02-16 1:17 ` Paul Mackerras
2007-02-16 9:41 ` Segher Boessenkool
2007-02-15 0:10 ` Segher Boessenkool
2007-02-14 23:32 ` David Gibson
2007-02-14 23:27 ` David Gibson
2007-02-14 23:22 ` David Gibson
2007-02-14 23:51 ` Benjamin Herrenschmidt
2007-02-15 0:36 ` Segher Boessenkool
2007-02-15 0:31 ` Segher Boessenkool
2007-02-15 1:53 ` David Gibson
2007-02-15 3:09 ` Segher Boessenkool
2007-02-15 3:33 ` David Gibson
2007-02-15 14:47 ` Segher Boessenkool [this message]
2007-02-15 10:52 ` Benjamin Herrenschmidt
2007-02-15 14:52 ` Segher Boessenkool
2007-02-15 20:43 ` Benjamin Herrenschmidt
2007-02-16 9:23 ` Segher Boessenkool
2007-02-15 16:37 ` Yoder Stuart-B08248
2007-02-15 21:41 ` Benjamin Herrenschmidt
2007-02-16 9:25 ` Segher Boessenkool
2007-02-16 15:32 ` Hartmut Penner
2007-02-16 16:47 ` Yoder Stuart-B08248
2007-02-19 12:02 ` Hartmut Penner
2007-02-14 21:29 ` Benjamin Herrenschmidt
2007-02-13 14:37 ` [0/16] Preliminary Ebony (440GP) support for arch/powerpc Josh Boyer
2007-02-13 20:21 ` Josh Boyer
2007-02-13 15:46 ` Josh Boyer
2007-02-14 16:06 ` Josh Boyer
2007-02-14 23:12 ` David Gibson
2007-02-16 2:19 ` Josh Boyer
2007-02-16 2:53 ` David Gibson
2007-02-16 4:33 ` Josh Boyer
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