Subject: Re: [RFC/PATCH 3/7] Powerpc MSI ops layer

From: Michael Ellerman <[email-masked]>
Date: Tue, 24 Oct 2006 11:51:28 +1000

On Tue, 2006-10-03 at 16:54 -0500, Jake Moilanen wrote:
> On Fri, 2006-09-29 at 07:53 +1000, Michael Ellerman wrote:
> > Powerpc MSI ops layer.
> > 
> > Signed-off-by: Michael Ellerman <[email-masked]>
> > ---
> > 
> >  arch/powerpc/kernel/msi.c        |  347 +++++++++++++++++++++++++++++++++++++++
> >  include/asm-powerpc/machdep.h    |    6 
> >  include/asm-powerpc/msi.h        |  175 +++++++++++++++++++
> >  include/asm-powerpc/pci-bridge.h |    4 
> >  4 files changed, 532 insertions(+)
> > 
> > Index: to-merge/arch/powerpc/kernel/msi.c
> > ===================================================================
> > --- /dev/null
> > +++ to-merge/arch/powerpc/kernel/msi.c
> > @@ -0,0 +1,347 @@
> > +/*
> > + * Copyright 2006 (C), Michael Ellerman, IBM Corporation.
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * as published by the Free Software Foundation; either version
> > + * 2 of the License, or (at your option) any later version.
> > + */
> > +
> > +#undef DEBUG
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/slab.h>
> > +#include <asm/msi.h>
> > +#include <asm/machdep.h>
> > +
> > +static struct ppc_msi_ops *get_msi_ops(struct pci_dev *pdev)
> > +{
> > +	if (ppc_md.get_msi_ops)
> > +		return ppc_md.get_msi_ops(pdev);
> > +	return NULL;
> > +}
> > +
> > +/* Activated by pci=nomsi on the command line. */
> > +static int no_msi;
> > +
> > +void pci_no_msi(void)
> > +{
> > +	no_msi = 1;
> > +}
> > +
> > +
> > +/* msi_info helpers */
> > +
> > +static struct pci_dn *get_pdn(struct pci_dev *pdev)
> > +{
> > +	struct device_node *dn;
> > +	struct pci_dn *pdn;
> > +
> > +	dn = pci_device_to_OF_node(pdev);
> > +	if (!dn) {
> > +		pr_debug("get_pdn: no dn found for %s\n", pci_name(pdev));
> > +		return NULL;
> > +	}
> > +
> > +	pdn = PCI_DN(dn);
> > +	if (!pdn) {
> > +		pr_debug("get_pdn: no pci_dn found for %s\n", pci_name(pdev));
> > +		return NULL;
> > +	}
> > +
> > +	return pdn;
> > +}
> > +
> > +static int alloc_msi_info(struct pci_dev *pdev, int num,
> > +			struct msix_entry *entries, int type)
> > +{
> > +	struct msi_info *info;
> > +	unsigned int entries_size;
> > +	struct pci_dn *pdn;
> > +
> > +	entries_size = sizeof(struct msix_entry) * num;
> > +
> > +	info = kzalloc(sizeof(struct msi_info) + entries_size, GFP_KERNEL);
> 
> Shouldn't you do a second kzalloc for info->entries, and not just add on
> the size to the end?

We could, but I don't see why it's better. It's a little sneaky to tack
the entries on the end but I don't see a problem with it?

There is a bug in there that I don't set the entries pointer before
doing the memcpy, but I've fixed that - or is that what you meant ? :)

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