Re: [RFC PATCH v3 02/16] cxl/acpi: Add an acpi_cxl module for the CXL interconnect

From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Ben Widawsky <ben.widawsky@intel.com>,
	<linux-cxl@vger.kernel.org>,
	"Vishal Verma" <vishal.l.verma@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	"linux-acpi@vger.kernel.org, Ira Weiny" <ira.weiny@intel.com>,
	"Kelley, Sean V" <sean.v.kelley@intel.com>,
	Rafael Wysocki <rafael.j.wysocki@intel.com>,
	Bjorn Helgaas <helgaas@kernel.org>,
	Jon Masters <jcm@jonmasters.org>,
	"Chris Browy" <cbrowy@avery-design.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Christoph Hellwig <hch@infradead.org>,
	<daniel.lll@alibaba-inc.com>,
	"Moore, Robert" <robert.moore@intel.com>,
	"Kaneda, Erik" <erik.kaneda@intel.com>
Subject: Re: [RFC PATCH v3 02/16] cxl/acpi: Add an acpi_cxl module for the CXL interconnect
Date: Tue, 12 Jan 2021 22:06:28 +0000	[thread overview]
Message-ID: <20210112220628.000037fb@Huawei.com> (raw)
In-Reply-To: <CAPcyv4hcppMZ2L8W8arUKmbCo0r=_yZggrnsj3w-Jgszjn=ZoA@mail.gmail.com>

On Tue, 12 Jan 2021 11:43:31 -0800
Dan Williams <dan.j.williams@intel.com> wrote:

> On Tue, Jan 12, 2021 at 10:44 AM Jonathan Cameron
> <Jonathan.Cameron@huawei.com> wrote:
> >
> > On Mon, 11 Jan 2021 14:51:06 -0800
> > Ben Widawsky <ben.widawsky@intel.com> wrote:
> >  
> > > From: Vishal Verma <vishal.l.verma@intel.com>
> > >
> > > Add an acpi_cxl module to coordinate the ACPI portions of the CXL
> > > (Compute eXpress Link) interconnect. This driver binds to ACPI0017
> > > objects in the ACPI tree, and coordinates access to the resources
> > > provided by the ACPI CEDT (CXL Early Discovery Table).
> > >
> > > It also coordinates operations of the root port _OSC object to notify
> > > platform firmware that the OS has native support for the CXL
> > > capabilities of endpoints.
> > >
> > > Note: the actbl1.h changes are speculative. The expectation is that they
> > > will arrive through the ACPICA tree in due time.  
> >
> > I would pull the ACPICA changes out into a precursor patch.  
> 
> 
> >  
> > >
> > > Cc: Ben Widawsky <ben.widawsky@intel.com>
> > > Cc: Dan Williams <dan.j.williams@intel.com>
> > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
> > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>  
> >
> > Hi,
> >
> > I think it would be good to also add CEDT to the list in drivers/acpi/tables.c
> > so that we can dump it from /sys/firmware/acpi/tables/ and potentially
> > override it from an initrd.  
> 
> ACPICA changes will eventually come through the ACPI tree not this patch set.

That particular file isn't from ACPICA though I value in the entry will be.

> 
> 
> >
> > https://elixir.bootlin.com/linux/v5.11-rc3/source/drivers/acpi/tables.c#L482
> > Can be very helpful whilst debugging.  Related to that, anyone know if anyone
> > has acpica patches so we can have iasl -d work on the table?  Would probably
> > be useful but I'd rather not duplicate work if it's already done.
> >  
> 
> The supplemental tables described here:
> 
> https://www.uefi.org/acpi
> 
> ...do eventually make there way into ACPICA. Added Bob and Erik in
> case they can comment on when CEDT and CDAT support will be picked up.
...