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Subject: Re: [Cbe-oss-dev] [patch 11/11] powerpc/cell: Add
	DMA_ATTR_STRONG_ORDERING dma attribute and use in IOMMU code
From: Michael Ellerman <michael@ellerman.id.au>
To: arnd@arndb.de
In-Reply-To: <20080704190806.964824190@arndb.de>
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	<20080704190806.964824190@arndb.de>
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Date: Sat, 05 Jul 2008 15:43:04 +1000
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Cc: Paul Mackerras <paulus@samba.org>, cbe-oss-dev@ozlabs.org,
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On Fri, 2008-07-04 at 21:05 +0200, arnd@arndb.de wrote:

> Introduce a new dma attriblue DMA_ATTR_STRONG_ORDERING to use strong orde=
ring
> on DMA mappings in the Cell processor. Add the code to the Cell's IOMMU
> implementation to use this.
>=20
> The current Cell IOMMU implementation sets the IOPTE_SO_RW bits in all IO=
TPEs
> (for both the dynamic and fixed mappings) which enforces strong ordering =
of
> both reads and writes. This patch makes the default behaviour weak orderi=
ng
> (the IOPTE_SO_RW bits not set) and to request a strongly ordered mapping =
the
> new DMA_ATTR_STRONG_ORDERING needs to be used.

We're sure that's safe?

cheers

--=20
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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