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 8/8] Cell IOMMU fixed mapping support
Date: Tue, 29 Jan 2008 09:50:48 -0600 [thread overview]
Message-ID: <20080129155048.GA19822@lixom.net> (raw)
In-Reply-To: <1201619625.10012.19.camel@concordia>
On Wed, Jan 30, 2008 at 02:13:45AM +1100, Michael Ellerman wrote:
> 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.
Ben denied that being so yesterday. :-)
If that's the case, then you can stick the dynamic range there for >32GB
configs, since it's still addressable with 32 bits.
-Olof
next prev parent reply other threads:[~2008-01-29 15:50 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 2/8] Allocate the hash table under 1G on cell 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 14:14 ` [PATCH 4/8] Split cell_iommu_setup_hardware() into two parts Michael Ellerman
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 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 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
2008-01-29 15:50 ` Olof Johansson [this message]
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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