Re: [PATCH] Extending kernel option pci=resource_alignment to be able to specify PCI device/vendor IDs

Re: [PATCH] Extending kernel option pci=resource_alignment to be able to specify PCI device/vendor IDs

[Koehrer Mathias (ETAS/ESW5)]

Hi Bjorn,

> On Tue, Jun 07, 2016 at 02:24:17PM +0000, Koehrer Mathias (ETAS/ESW5) wro=
te:
> > Some uio based PCI drivers (e.g. uio_cif) do not work if the assigned
> > PCI memory resources are not page aligned.
> > By using the kernel option "pci=3Dresource_alignment" it is possible to
> > force single PCI boards to use page alignment for their memory resource=
s.
> > However, this is fairly cumbersome if multiple of these boards are in
> > use as the specification of the cards has to be done via PCI
> > bus/slot/function number which might change e.g. by adding another boar=
d.
> > This patch extends the kernel option "pci=3Dresource_alignment" to allo=
w
> > to specify the relevant boards via PCI device/vendor (and subdevice/sub=
vendor)
> ids.
> > The specification of the devices via device/vendor is indicated by a
> > leading string "pci:" as argument to "pci=3Dresource_alignment".
> > The format of the specification is
> >   pci:<vendor>:<device>[:<subvendor>:<subdevice>]
> >
> > Signed-off-by: Mathias Koehrer <mathias.koehrer@etas.com>
> >
> > ---
> >  Documentation/kernel-parameters.txt |    2 +
> >  drivers/pci/pci.c                   |   66 +++++++++++++++++++++++++--=
---------
> >  2 files changed, 49 insertions(+), 19 deletions(-)
> >
> > Index: linux-4.7-rc1/Documentation/kernel-parameters.txt
> >
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> =3D=3D=3D=3D=3D=3D=3D
> > --- linux-4.7-rc1.orig/Documentation/kernel-parameters.txt
> > +++ linux-4.7-rc1/Documentation/kernel-parameters.txt
> > @@ -2998,6 +2998,8 @@ bytes respectively. Such letter suffixes
> >  		resource_alignment=3D
> >  				Format:
> >  				[<order of
> align>@][<domain>:]<bus>:<slot>.<func>[; ...]
> > +				[<order of align>@]pci:<vendor>:<device>\
> > +						[:<subvendor>:<subdevice>][; ...]
>=20
> Can you include a little example here so we know whether to use "pci:8086=
:1234" or
> "pci:0x8086:0x1234"?
>=20
> Bjorn

I have provided an example and extended the docu (sent in  http://marc.info=
/?l=3Dlinux-pci&m=3D146657769505684&w=3D2 and http://marc.info/?l=3Dlinux-p=
ci&m=3D146918412704107&w=3D2 ).
It would be great if you could comment on the modified patch...

Thanks=20

Best regards

Mathias

Re: [PATCH] Extending kernel option pci=resource_alignment to be able to specify PCI device/vendor IDs

[Bjorn Helgaas]

On Mon, Aug 08, 2016 at 07:39:01AM +0000, Koehrer Mathias (ETAS/ESW5) wrote:
> Hi Bjorn,
> 
> > On Tue, Jun 07, 2016 at 02:24:17PM +0000, Koehrer Mathias (ETAS/ESW5) wrote:
> > > Some uio based PCI drivers (e.g. uio_cif) do not work if the assigned
> > > PCI memory resources are not page aligned.
> > > By using the kernel option "pci=resource_alignment" it is possible to
> > > force single PCI boards to use page alignment for their memory resources.
> > > However, this is fairly cumbersome if multiple of these boards are in
> > > use as the specification of the cards has to be done via PCI
> > > bus/slot/function number which might change e.g. by adding another board.
> > > This patch extends the kernel option "pci=resource_alignment" to allow
> > > to specify the relevant boards via PCI device/vendor (and subdevice/subvendor)
> > ids.
> > > The specification of the devices via device/vendor is indicated by a
> > > leading string "pci:" as argument to "pci=resource_alignment".
> > > The format of the specification is
> > >   pci:<vendor>:<device>[:<subvendor>:<subdevice>]
> > >
> > > Signed-off-by: Mathias Koehrer <mathias.koehrer@etas.com>
> > >
> > > ---
> > >  Documentation/kernel-parameters.txt |    2 +
> > >  drivers/pci/pci.c                   |   66 +++++++++++++++++++++++++-----------
> > >  2 files changed, 49 insertions(+), 19 deletions(-)
> > >
> > > Index: linux-4.7-rc1/Documentation/kernel-parameters.txt
> > >
> > ============================================================
> > =======
> > > --- linux-4.7-rc1.orig/Documentation/kernel-parameters.txt
> > > +++ linux-4.7-rc1/Documentation/kernel-parameters.txt
> > > @@ -2998,6 +2998,8 @@ bytes respectively. Such letter suffixes
> > >  		resource_alignment=
> > >  				Format:
> > >  				[<order of
> > align>@][<domain>:]<bus>:<slot>.<func>[; ...]
> > > +				[<order of align>@]pci:<vendor>:<device>\
> > > +						[:<subvendor>:<subdevice>][; ...]
> > 
> > Can you include a little example here so we know whether to use "pci:8086:1234" or
> > "pci:0x8086:0x1234"?
> > 
> > Bjorn
> 
> I have provided an example and extended the docu (sent in  http://marc.info/?l=linux-pci&m=146657769505684&w=2 and http://marc.info/?l=linux-pci&m=146918412704107&w=2 ).
> It would be great if you could comment on the modified patch...

It looks like I applied the patch, but I forgot to include the updated
documentation.  Can you confirm that?  If you send a documentation
patch to add the example, I can add that.

Bjorn

[PATCH] Extending kernel option pci=resource_alignment to be able to specify PCI device/vendor IDs - Documentation

[Mathias Koehrer]

Extend the documentation for kernel option pci=resource_alignment

Some uio based PCI drivers (e.g. uio_cif) do not work if the assigned 
PCI memory resources are not page aligned.
By using the kernel option "pci=resource_alignment" it is possible to force
single PCI boards to use page alignment for their memory resources.
However, this is fairly cumbersome if multiple of these boards are in use as 
the specification of the cards has to be done via PCI bus/slot/function number
which might change e.g. by adding another board.
This patch extends the kernel option "pci=resource_alignment" to allow to
specify the relevant boards via PCI device/vendor (and subdevice/subvendor) ids.
The specification of the devices via device/vendor is indicated by a leading
string "pci:" as argument to "pci=resource_alignment".
The format of the specification is
  pci:<vendor>:<device>[:<subvendor>:<subdevice>]

Examples: 
  pci=resource_alignment=4096@pci:1234:abcd:1234:bcde
  pci=resource_alignment=pci:1234:abcd

Signed-off-by: Mathias Koehrer <mathias.koehrer@etas.com>

---
 pci/Documentation/kernel-parameters.txt |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-pci-git/pci/Documentation/kernel-parameters.txt
===================================================================
--- linux-pci-git.orig/pci/Documentation/kernel-parameters.txt
+++ linux-pci-git/pci/Documentation/kernel-parameters.txt
@@ -3032,6 +3032,9 @@ bytes respectively. Such letter suffixes
 				PAGE_SIZE is used as alignment.
 				PCI-PCI bridge can be specified, if resource
 				windows need to be expanded.
+				To specify the alignment for certain types of devices, the
+				PCI vendor/device (and subvendor/subdevice) may be
+				specified. E.g. 4096@pci:1234:abcd:1234:bcde
 		ecrc=		Enable/disable PCIe ECRC (transaction layer
 				end-to-end CRC checking).
 				bios: Use BIOS/firmware settings. This is the