From: Olof Johansson <olof@lixom.net>
To: Michael Ellerman <michael@ellerman.id.au>
Cc: linuxppc-dev@ozlabs.org, cbe-oss-dev@ozlabs.org
Subject: Re: [PATCH 3/3] Cell IOMMU static mapping support
Date: Fri, 25 Jan 2008 20:51:17 -0600 [thread overview]
Message-ID: <20080126025117.GA28066@lixom.net> (raw)
In-Reply-To: <9ce4678eef9e50908969eb1ef8470e307f3076ff.1201257905.git.michael@ellerman.id.au>
On Fri, Jan 25, 2008 at 09:45:07PM +1100, Michael Ellerman wrote:
> Citing "release early release often", I'm posting this now as a mega-patch
> to get people looking at it. I'll try to split it up and make it look a
> little prettier before submitting it.
>
> The intent of this patch is to setup (on certain machines) a "static" IOMMU
> mapping of all of memory, to reduce the overhead of the IOMMU. If anyone has
> a better name than "static" I'm all ears.
>
> So instead of having an IOMMU window that we use to temporarily map things
> in and out of DMA'able space, at boot we create a 1:1 mapping for all of
> memory. This obviously only works for devices that can do 64-bit DMA.
I don't get it. Why not disable the iommu instead?
-Olof
next prev parent reply other threads:[~2008-01-26 2:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-25 10:45 [PATCH 1/3] Add set_dma_ops() to match get_dma_ops() Michael Ellerman
2008-01-25 10:45 ` [PATCH 2/3] Allocate the hash table under 1G on cell Michael Ellerman
2008-02-05 0:23 ` Benjamin Herrenschmidt
2008-01-25 10:45 ` [PATCH 3/3] Cell IOMMU static mapping support Michael Ellerman
2008-01-25 13:12 ` [Cbe-oss-dev] " Geert Uytterhoeven
2008-01-26 2:51 ` Olof Johansson [this message]
2008-01-28 11:41 ` Arnd Bergmann
2008-01-28 16:23 ` Olof Johansson
2008-01-28 21:16 ` Benjamin Herrenschmidt
2008-01-28 21:48 ` Olof Johansson
2008-01-28 21:37 ` Benjamin Herrenschmidt
2008-01-28 21:18 ` Benjamin Herrenschmidt
2008-02-05 0:23 ` [PATCH 1/3] Add set_dma_ops() to match get_dma_ops() Benjamin Herrenschmidt
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