[RFC/PATCH 14/16] MPIC MSI backend

[Michael Ellerman]

On Sat, 2007-01-27 at 09:08 +1100, Benjamin Herrenschmidt wrote:
> > >From that comes our need for a data structure to map from an irq to a
> > msi data structure in a generic fashion, because we don't just program
> > the pci card and forget about it.  From those requirements comes our
> > need for a little bit more complete support of the features of the
> > hardware that Michaels implementation.
> 
> Well, we need to go from pci_dev -> MSI and from linux irq_desc ->
> MSI... for now, we can get away without the later on powerpc, but I
> understand that intel needs that. The initial intel code used an array
> of NR_IRQs, but that sucks. What I remember of your patch is that they
> were using chip_data in irq_desc.

There's still an array of NR_IRQs msi_desc*, which are also attached to
the irq_desc.

The msi_desc is allocated and immediately attached to the irq_desc. Then
later it gets hooked into the array (attach_msi_entry) - I don't
understand why both methods are necessary - they both require the irq.

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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