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From: Scott Wood <scottwood@freescale.com>
To: Timur Tabi <timur@freescale.com>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: [PATCH 2/5] [POWERPC] QE: add support for QE USB clocks routing
Date: Thu, 17 Apr 2008 15:26:23 -0500	[thread overview]
Message-ID: <4807B26F.2020107@freescale.com> (raw)
In-Reply-To: <4807B062.3080004@freescale.com>

Timur Tabi wrote:
> Scott Wood wrote:
> 
>> That's implementation dependent, and support for accesses to uncached 
>> memory is being phased out of book E according to the E500 manual.
> 
> What's wrong with uncached memory?

The typical implementation of lwarx/stwcx depends on holding the 
reserved cache line in exclusive state, and stwcx failing if it is no 
longer exclusive.

> I figured that if I could use lwarx/stwcx to make clrsetbits atomic, there would
> be no need to spinlocks protecting an individual register.

OK, so you're not trying to be atomic with respect to the device, just 
with respect to other cores?  Just use the spinlock.

-Scott

  reply	other threads:[~2008-04-17 20:25 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-17 19:26 [PATCH 0/5] Few more patches for Kumar's powerpc.git Anton Vorontsov
2008-04-17 19:28 ` [PATCH 1/5] [POWERPC] sysdev: implement FSL GTM support Anton Vorontsov
2008-04-17 22:47   ` Anton Vorontsov
2008-04-18  4:19     ` Kumar Gala
2008-04-18  9:54       ` Anton Vorontsov
2008-04-17 19:28 ` [PATCH 2/5] [POWERPC] QE: add support for QE USB clocks routing Anton Vorontsov
2008-04-17 19:56   ` Timur Tabi
2008-04-17 19:59     ` Scott Wood
2008-04-17 20:04       ` Timur Tabi
2008-04-17 20:14         ` Scott Wood
2008-04-17 20:17           ` Timur Tabi
2008-04-17 20:26             ` Scott Wood [this message]
2008-04-17 20:47     ` Dale Farnsworth
2008-04-17 20:49       ` Timur Tabi
2008-04-17 20:54         ` Dale Farnsworth
2008-04-17 21:48     ` Anton Vorontsov
2008-04-17 22:00       ` Timur Tabi
2008-04-17 19:28 ` [PATCH 3/5] [POWERPC] QE: split par_io_config_pin() Anton Vorontsov
2008-04-17 21:53   ` Kumar Gala
2008-04-17 22:35     ` Anton Vorontsov
2008-04-17 19:29 ` [PATCH 4/5] [POWERPC] QE: implement support for the GPIO LIB API Anton Vorontsov
2008-04-17 22:35   ` Kumar Gala
2008-04-17 22:41     ` Anton Vorontsov
2008-04-18  2:21       ` Kumar Gala
2008-04-17 19:29 ` [PATCH 5/5] [POWERPC] 83xx: new board support: MPC8360E-RDK Anton Vorontsov
  -- strict thread matches above, loose matches on Subject: below --
2008-04-18 19:06 [PATCH 0/5 v2] Few more patches for Kumar's powerpc.git Anton Vorontsov
2008-04-18 19:09 ` [PATCH 2/5] [POWERPC] QE: add support for QE USB clocks routing Anton Vorontsov

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