From: Anton Vorontsov <avorontsov@ru.mvista.com>
To: Scott Wood <scottwood@freescale.com>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: [PATCH RFC 0/7] "NAND on UPM" and related patches
Date: Wed, 12 Dec 2007 19:55:14 +0300 [thread overview]
Message-ID: <20071212165513.GA30981@localhost.localdomain> (raw)
In-Reply-To: <20071212164035.GB4329@loki.buserror.net>
On Wed, Dec 12, 2007 at 10:40:35AM -0600, Scott Wood wrote:
> On Mon, Dec 10, 2007 at 11:47:05PM +0300, Anton Vorontsov wrote:
> > 5 - FSL UPM infrastructure:
> > ---------------------------
> > UPM address register is shared among UPMs, so we have to do
> > proper locking. On the other hand, if we know that specific
> > board using only one UPM we could bypass locking, and gain some
> > performance win.
>
> Not enough to be worth the complexity compared to the overhead of NAND
> access -- especially in the likely case of a non-SMP build.
I'm allowing UPM access from the IRQ handlers (because nothing prevents
this, so why deny?). Thus locks are needed even on non-SMP build, on
UP they aren't thrown away. Lockless variant occupy less than 30 lines of
code, so I'd rather keep it.
--
Anton Vorontsov
email: cbou@mail.ru
backup email: ya-cbou@yandex.ru
irc://irc.freenode.net/bd2
next prev parent reply other threads:[~2007-12-12 16:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-10 20:47 [PATCH RFC 0/7] "NAND on UPM" and related patches Anton Vorontsov
2007-12-10 20:48 ` [PATCH RFC 1/7] [POWERPC] Implement GPIO API embryo Anton Vorontsov
2007-12-12 16:48 ` Scott Wood
2007-12-12 17:10 ` Anton Vorontsov
2007-12-10 20:48 ` [PATCH RFC 2/7] [POWERPC] QE: implement GPIO API Anton Vorontsov
2007-12-10 20:48 ` [PATCH RFC 3/7] [POWERPC] CPM2: " Anton Vorontsov
2007-12-12 15:49 ` Jochen Friedrich
2007-12-12 16:03 ` Anton Vorontsov
2007-12-12 16:56 ` Scott Wood
2007-12-10 20:49 ` [PATCH RFC 4/7] [GPIO] Let drivers link if they support GPIO API as an addition Anton Vorontsov
2007-12-10 22:55 ` David Brownell
2007-12-10 23:04 ` Anton Vorontsov
2008-02-22 23:42 ` David Brownell
2008-02-22 23:35 ` Anton Vorontsov
2007-12-10 20:49 ` [PATCH RFC 5/7] [POWERPC] FSL UPM: routines to manage FSL UPMs Anton Vorontsov
2007-12-10 20:49 ` [PATCH RFC 6/7] [POWERPC][NAND] FSL UPM NAND driver Anton Vorontsov
2007-12-10 20:49 ` [PATCH RFC 7/7] [POWERPC] MPC8360E-RDK: add support for NAND on UPM Anton Vorontsov
2007-12-10 23:03 ` David Gibson
2007-12-10 23:16 ` Anton Vorontsov
2007-12-12 16:59 ` Scott Wood
2007-12-10 23:04 ` [PATCH RFC 0/7] "NAND on UPM" and related patches David Gibson
2007-12-10 23:10 ` Anton Vorontsov
2007-12-11 0:36 ` David Gibson
2007-12-12 12:47 ` Anton Vorontsov
2007-12-16 6:44 ` David Gibson
2007-12-12 16:39 ` Scott Wood
2007-12-12 16:40 ` Scott Wood
2007-12-12 16:55 ` Anton Vorontsov [this message]
2007-12-12 16:54 ` Scott Wood
2007-12-12 20:58 ` Anton Vorontsov
2007-12-12 21:06 ` Scott Wood
2007-12-12 21:13 ` Scott Wood
2007-12-13 14:09 ` Anton Vorontsov
2007-12-13 3:01 ` Chris Fester
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