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From: Michael Ellerman <michael@ellerman.id.au>
To: Olof Johansson <olof@lixom.net>
Cc: linuxppc-dev@ozlabs.org, cbe-oss-dev@ozlabs.org
Subject: Re: [PATCH 8/8] Cell IOMMU fixed mapping support
Date: Wed, 30 Jan 2008 02:13:45 +1100	[thread overview]
Message-ID: <1201619625.10012.19.camel@concordia> (raw)
In-Reply-To: <20080129151511.GA18975@lixom.net>

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On Tue, 2008-01-29 at 09:15 -0600, Olof Johansson wrote:
> On Wed, Jan 30, 2008 at 01:14:03AM +1100, Michael Ellerman wrote:
> 
> > For example a machine with 4GB of memory would end up with the normal
> > IOMMU window from 0-2GB and the fixed mapping window from 2GB to 6GB. In
> > this case a 64-bit device wishing to DMA to 1GB would be told to DMA to
> > 3GB, plus any offset required by firmware. The firmware offset is encoded
> > in the "dma-ranges" property.
> 
> Shouldn't the fixed mapping be between 4G and 8G (and the offset for 1G
> is at 5G), to account for the MMIO range at 2-4G?

I don't think so, ie. it works setup like that, but I'm not entirely
sure why. Presumably the 2-4GB for MMIO is only for cycles heading out
of the CPU.

cheers

-- 
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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  reply	other threads:[~2008-01-29 15:13 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-29 14:13 [PATCH 1/8] Add set_dma_ops() to match get_dma_ops() Michael Ellerman
2008-01-29 14:13 ` [PATCH 3/8] Split out the logic that allocates struct iommus Michael Ellerman
2008-02-05  0:23   ` Benjamin Herrenschmidt
2008-01-29 14:13 ` [PATCH 2/8] Allocate the hash table under 1G on cell Michael Ellerman
2008-01-29 14:14 ` [PATCH 4/8] Split cell_iommu_setup_hardware() into two parts Michael Ellerman
2008-01-29 14:14 ` [PATCH 6/8] Add support to cell_iommu_setup_page_tables() for multiple windows Michael Ellerman
2008-02-05  0:26   ` Benjamin Herrenschmidt
2008-01-29 14:14 ` [PATCH 5/8] Split out the IOMMU logic from cell_dma_dev_setup() Michael Ellerman
2008-02-05  0:26   ` Benjamin Herrenschmidt
2008-01-29 14:14 ` [PATCH 7/8] Split out the ioid fetching/checking logic Michael Ellerman
2008-02-05  0:27   ` Benjamin Herrenschmidt
2008-01-29 14:14 ` [PATCH 8/8] Cell IOMMU fixed mapping support Michael Ellerman
2008-01-29 15:15   ` Olof Johansson
2008-01-29 15:13     ` Michael Ellerman [this message]
2008-01-29 15:50       ` Olof Johansson
2008-01-30  0:54         ` Arnd Bergmann
2008-01-30  0:58           ` Olof Johansson
2008-01-29 21:18       ` Benjamin Herrenschmidt
2008-01-29 21:36         ` Olof Johansson
2008-01-29 23:56           ` Michael Ellerman
2008-01-30  0:03   ` Michael Ellerman

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