Re: [EXT] Re: Help on named object in kernel

[Sudeep Holla <sudeep.holla@arm.com>]

On Thu, Jun 13, 2019 at 01:20:32AM +0000, Udit Kumar wrote:
>
>
> > -----Original Message-----
> > From: linux-acpi-owner@vger.kernel.org <linux-acpi-owner@vger.kernel.org>
> > On Behalf Of Sudeep Holla
> > Sent: Wednesday, June 12, 2019 10:31 PM
> > To: Schmauss, Erik <erik.schmauss@intel.com>
> > Cc: Udit Kumar <udit.kumar@nxp.com>; ACPI Devel Maling List <linux-
> > acpi@vger.kernel.org>; lenb@kernel.org; Sudeep Holla
> > <sudeep.holla@arm.com>; Rafael J. Wysocki <rafael@kernel.org>
> > Subject: [EXT] Re: Help on named object in kernel
> >
> > Caution: EXT Email
> >
> > On Wed, Jun 12, 2019 at 04:37:09PM +0000, Schmauss, Erik wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
> > > > owner@vger.kernel.org] On Behalf Of Udit Kumar
> > > > Sent: Wednesday, June 12, 2019 4:48 AM
> > > > To: ACPI Devel Maling List <linux-acpi@vger.kernel.org>
> > > > Cc: lenb@kernel.org; Rafael J. Wysocki <rafael@kernel.org>
> > > > Subject: Help on named object in kernel
> > > >
> > > > Dear ACPI experts,
> > > > I need your help on defining named objected in ACPI under _CRS.
> > > > In my firmware, I have defined two addresses for my device using
> > > > Memory32Fixed and QwordMemory under _CRS.
> > > > These  two addresses are 32-bit and 64-bit long respectively.
> > > > For Memory32Fixed, I gave DescriptorName name as REG0 and for
> > > > QwordMemory I gave DescriptorName as SATA.
> > >
> > > Could you give us the ASL for the code snippet that you're talking about?
> > >
> >
> > IIUC, something like below(a very rough example based on the description
> > above):
> >
> >     Name (_CRS, ResourceTemplate (){
> >       QwordMemory (
> >         ResourceConsumer, PosDecode, MinFixed, MaxFixed, NonCacheable,
> >         ReadWrite, 0x0, 0x700100520, 0x700100523, 0x0, 4, , , "SATA",)
> >       Memory32Fixed(ReadWrite, 0x3200000, 0x10000, "REG0")
> >     }
> >
> > Basically 2 or more entries of Memory/Address Space Resource Descriptor
> > which can be identified in OSPM by DescriptorName. IOW if a device has
> > 2 sets of registers/memory/address space associated with it, instead of relying
> > on the order of declaration, identify them by the descriptor name provided in
> > ASL namespace.
>
> Thanks Sudeep,
> Shouldn't acpi frame work encapsulate descriptor name  while adding resource.
> So that driver can rely on platform_get_resource_byname .
> In such way, same driver could be used with device tree and acpi based systems.
>
> I am not sure, if acpi_evaluate_xx sort of api would work for
> descriptor-name , even if this does it will be limited to acpi only.
>

IIUC acpi_resource_source should have all the information, just not
used for this purpose yet. I do see some uses of string_ptr in that
elsewhere. I haven't tried it, but looking at the code I think the
support is there already.

But the question is who/where will the list of names for such resource
is listed for a given HID/CID/... ?
--
Regards,
Sudeep