Hi Mika

-----Original Message-----
From: linux-pci-owner at vger.kernel.org [mailto:linux-pci-
owner at vger.kernel.org] On Behalf Of Gabriele Paoloni
Sent: 19 June 2017 11:05
To: Mika Westerberg
Cc: Rafael J. Wysocki; Lorenzo Pieralisi; Rafael J. Wysocki;
catalin.marinas at arm.com; will.deacon at arm.com; robh+dt at kernel.org;
frowand.list at gmail.com; bhelgaas at google.com; arnd at arndb.de; linux-arm-
kernel at lists.infradead.org; mark.rutland at arm.com;
brian.starkey at arm.com; olof at lixom.net; benh at kernel.crashing.org; linux-
kernel at vger.kernel.org; linux-acpi at vger.kernel.org; Linuxarm; linux-
pci at vger.kernel.org; minyard at acm.org; John Garry; xuwei (O)
Subject: RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
devices before scanning

Hi Mika

quoted

-----Original Message-----
From: Mika Westerberg [mailto:mika.westerberg at linux.intel.com]
Sent: 19 June 2017 11:02
To: Gabriele Paoloni
Cc: Rafael J. Wysocki; Lorenzo Pieralisi; Rafael J. Wysocki;
catalin.marinas at arm.com; will.deacon at arm.com; robh+dt at kernel.org;
frowand.list at gmail.com; bhelgaas at google.com; arnd at arndb.de; linux-

arm-

quoted

kernel at lists.infradead.org; mark.rutland at arm.com;
brian.starkey at arm.com; olof at lixom.net; benh at kernel.crashing.org;

linux-

quoted

kernel at vger.kernel.org; linux-acpi at vger.kernel.org; Linuxarm; linux-
pci at vger.kernel.org; minyard at acm.org; John Garry; xuwei (O)
Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
devices before scanning

On Mon, Jun 19, 2017 at 09:50:49AM +0000, Gabriele Paoloni wrote:

quoted

Many thanks for your response and your help here.

I guess that as conclusion with respect to the current v9 patchset

we

quoted

can

quoted

disregard the idea of MFD and modify the current v9 so that it

doesn't

quoted

touch directly ACPI resources.
Instead as I proposed before we can have the scan handler to

enumerate

quoted

the children devices and translate its addresses filling dev-
resources[] and
at the same time we can modify acpi_default_enumeration to check
acpi_device_enumerated() before continuing with device

enumeration...?

quoted

Do you think it as a viable solution?

No, I think MFD + scan handler inside the MFD driver is the way to

go.

quoted

We don't want to trash ACPI core with stuff that does not belong

there

quoted

IMHO.

Ok Many thanks I will investigate this direction

I had a look into the MFD framework. If my understanding is correct the mfd
framework create a platform device for each declared mfd_cell that is passed
to mfd_add_devices().
However there is something that I do not quite understand:
from
http://elixir.free-electrons.com/linux/latest/source/drivers/mfd/mfd-core.c#L207
it seems that mfd_add_device() will create the platform device using the
resources that are statically declared in the respective mfd_cell.

In my case I'd like to have a platform device using the resources that are
parsed from the ACPI table (i.e. as it is done now by 
acpi_create_platform_device()).

If my understanding is correct, if I declared an mfd_cell for my IPMI child
the mfd subsystem would create a platform device for such child and
therefore acpi_create_platform_device() would fail to create a new platform
device as adev->physical_node_count will be non zero.
However as things stand now mfd_cell devices can only use the resources
that are statically defined in the code (and therefore not the ones in the
ACPI nodes)...am I right?

Thanks
Gab

quoted

Also you don't need to modify acpi_default_enumeration() because you
can
mark your device enumerated in the MFD driver. So all the dirty

details

quoted

will be in the MFD driver and not in ACPI core.

Ok got it :)

Cheers
Gab