From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Andres Salomon <dilinger@queued.net>
Cc: David Miller <davem@davemloft.net>,
grant.likely@secretlab.ca, devicetree-discuss@lists.ozlabs.org,
sparclinux@vger.kernel.org, x86@kernel.org, tglx@linutronix.de,
mingo@redhat.com, hpa@zytor.com, cjb@laptop.org, wmb@laptop.org,
pgf@laptop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] sparc: break out some prom device-tree building code out into drivers/of
Date: Tue, 06 Jul 2010 20:17:33 +1000 [thread overview]
Message-ID: <1278411453.1665.273.camel@pasglop> (raw)
In-Reply-To: <20100707051548.2c44f30c@debxo>
> Sounds like we have a winner. I'll concentrate on that, thanks for
> the heads up.
Note that the conversion from OF -> fdt that powerpc does is a bit
"special". The code isn't quite a "wrapper" but almost. It shared pretty
much no symbols or variables with the rest of the kernel.
There are various reasons for that. It has to run -very- early, in fact,
before we do anything else at boot time, since we run off OF existing
environment (stack etc...) at at whatever address the kernel is loaded,
ie. before we relocate it down to 0.
To deal with that, we use compile/linker tricks to generate
pseudo-relocatable code (with limitations) and funny macros when
accessing global symbols.
In addition, we have various workarounds for powerpc specific
implementation issues (OF bugs, but also instanciating the IOMMU tables
on Power4, starting secondary CPUs and parking them in a wait loop,
etc...).
Thus I'm not sure there's that much benefit in trying to make that code
common with other archs, and possibly a lot of pain involved.
Cheers,
Ben.
next prev parent reply other threads:[~2010-07-06 10:20 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-29 1:54 [PATCH 0/4] RFC: OLPC/x86 device tree code Andres Salomon
2010-06-29 2:00 ` [PATCH 1/4] x86: OLPC: constify an olpc_ofw() arg Andres Salomon
2010-07-31 1:10 ` [tip:x86/olpc] x86, olpc: Constify " tip-bot for Andres Salomon
2010-06-29 2:00 ` [PATCH 2/4] sparc: break out some prom device-tree building code out into drivers/of Andres Salomon
2010-06-29 3:11 ` David Miller
2010-06-29 6:15 ` Stephen Rothwell
2010-06-29 7:50 ` Grant Likely
2010-06-29 15:03 ` Andres Salomon
2010-06-29 21:42 ` Grant Likely
2010-06-29 23:36 ` Andres Salomon
2010-06-30 21:52 ` Grant Likely
2010-07-07 4:07 ` Andres Salomon
2010-07-06 2:22 ` David Miller
2010-07-06 7:00 ` Grant Likely
2010-07-06 7:16 ` David Miller
2010-07-06 8:17 ` Grant Likely
2010-07-07 5:15 ` Andres Salomon
2010-07-06 10:17 ` Benjamin Herrenschmidt [this message]
2010-07-06 8:17 ` Grant Likely
2010-07-06 9:21 ` Grant Likely
2010-07-06 21:54 ` Andres Salomon
2010-07-06 22:06 ` Grant Likely
2010-07-07 1:15 ` Andres Salomon
2010-06-29 2:00 ` [PATCH 3/4] proc: unify PROC_DEVICETREE config Andres Salomon
2010-06-29 7:33 ` Grant Likely
2010-06-29 2:00 ` [PATCH 4/4] x86: OLPC: add OLPC device-tree support Andres Salomon
2010-06-29 8:12 ` Grant Likely
2010-06-29 8:33 ` Stephen Rothwell
2010-06-29 14:23 ` Andres Salomon
2010-06-30 21:13 ` Grant Likely
2010-06-30 21:32 ` Andres Salomon
2010-08-30 3:51 ` [PATCH 0/9] " Andres Salomon
2010-08-30 3:53 ` [PATCH 1/9] of: move phandle/ihandle into types.h Andres Salomon
2010-08-30 5:06 ` Sam Ravnborg
2010-09-03 8:17 ` Andres Salomon
2010-09-05 6:22 ` Sam Ravnborg
2010-08-30 3:55 ` [PATCH 2/9] sparc: convert various prom_* functions to use phandle Andres Salomon
2010-08-30 3:57 ` [PATCH 3/9] sparc: break out some PROM device-tree building code out into drivers/of Andres Salomon
2010-08-30 3:59 ` [PATCH 4/9] sparc: make drivers/of/pdt.c no longer sparc-only Andres Salomon
2010-08-30 4:00 ` [PATCH 5/9] of: no longer call prom_ functions directly; use an ops structure Andres Salomon
2010-08-30 4:02 ` [PATCH 6/9] of: add of_pdt namespace to pdt code Andres Salomon
2010-08-30 4:04 ` [PATCH 7/9] of: add package-to-path support to pdt Andres Salomon
2010-08-30 4:06 ` [PATCH 8/9] x86: of: irq additions to make drivers/of/* build on x86 Andres Salomon
2010-08-30 15:58 ` Stephen Neuendorffer
2010-08-30 17:31 ` Grant Likely
2010-08-30 4:07 ` [PATCH 9/9] x86: OLPC: add OLPC device-tree support Andres Salomon
2010-08-30 18:14 ` Grant Likely
2010-08-30 18:49 ` Andres Salomon
2010-08-31 5:49 ` Grant Likely
2010-08-30 17:58 ` [PATCH 0/9] " Grant Likely
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