linux-cxl.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Dan Williams <dan.j.williams@intel.com>
To: Ben Widawsky <ben.widawsky@intel.com>
Cc: linux-cxl@vger.kernel.org,
	Alison Schofield <alison.schofield@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Vishal Verma <vishal.l.verma@intel.com>
Subject: Re: [PATCH 10/23] cxl/decoder: Support parentless decoders
Date: Fri, 30 Jul 2021 14:03:38 -0700	[thread overview]
Message-ID: <CAPcyv4hoUWj_4cDMRszoz5ZcsUBGXE=jX9E5khE=3x97GxJJ7w@mail.gmail.com> (raw)
In-Reply-To: <20210723210623.114073-11-ben.widawsky@intel.com>

On Fri, Jul 23, 2021 at 2:06 PM Ben Widawsky <ben.widawsky@intel.com> wrote:
>
> Currently, an ACPI0017 device (opaque platform thing) is parent to an
> ACPI0016 device (platform host bridge) child.

ACPI0017 is not a parent of ACPI0016 in the device hierarchy described
in the DSDT.

Linux does not even see ACPI0016 devices because the PCIE host-bridge
identifier dominates.

> The platform level
> decoders don't need a parent child relationship in order to traverse CXL
> hierarchy since once you get to these devices, you have a useless ACPI
> device instead of a CXL one.

The relationship is important for sysfs otherwise the root decoders
are floating in the sysfs hierarchy. For example, with this patch:

# ls /sys/devices/
breakpoint  decoder0.1  LNXSYSTM:00  pci0000:00  platform  software
tracepoint  virtual
decoder0.0  kprobe      msr          pci0000:34  pnp0      system    uprobe

...yuck, CXL decoders floating at the root of /sys/devices

> To support an upcoming expansion for CXL endpoints to be able to
> enumerate their decoders, support this NULL parent as a way to help
> distinguish decoder types.

Need to find a better way to make that distinction...

  reply	other threads:[~2021-07-30 21:03 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-23 21:06 [PATCH RFCish 00/23] cxl_region and cxl_memdev drivers Ben Widawsky
2021-07-23 21:06 ` [PATCH 01/23] cxl: Move cxl_core to new directory Ben Widawsky
2021-07-23 21:06 ` [PATCH 02/23] cxl/core: Improve CXL core kernel docs Ben Widawsky
2021-07-23 21:06 ` [PATCH 03/23] cxl/core: Extract register and pmem functionality Ben Widawsky
2021-07-23 21:06 ` [PATCH 04/23] cxl/mem: Move character device region creation Ben Widawsky
2021-07-23 21:06 ` [PATCH 05/23] cxl: Pass fops and shutdown to memdev creation Ben Widawsky
2021-07-23 21:06 ` [PATCH 06/23] cxl/core: Move memdev management to core Ben Widawsky
2021-07-23 21:06 ` [PATCH 07/23] cxl/pci: Ignore unknown register block types Ben Widawsky
2021-07-23 21:06 ` [PATCH 08/23] cxl/pci: Simplify register setup Ben Widawsky
2021-07-23 21:06 ` [PATCH 09/23] cxl/pci: Retain map information in cxl_mem_probe Ben Widawsky
2021-07-23 21:06 ` [PATCH 10/23] cxl/decoder: Support parentless decoders Ben Widawsky
2021-07-30 21:03   ` Dan Williams [this message]
2021-07-23 21:06 ` [PATCH 11/23] cxl: Enable an endpoint decoder type Ben Widawsky
2021-07-23 21:06 ` [PATCH 12/23] cxl/region: Add region creation ABI Ben Widawsky
2021-08-14  2:19   ` Dan Williams
2021-08-26 21:01     ` Ben Widawsky
2021-08-26 21:44       ` Dan Williams
2021-07-23 21:06 ` [PATCH 13/23] cxl/region: Introduce concept of region configuration Ben Widawsky
2021-07-23 21:06 ` [PATCH 14/23] cxl: Convert driver id to an enum Ben Widawsky
2021-07-23 21:06 ` [PATCH 15/23] cxl/region: Introduce a cxl_region driver Ben Widawsky
2021-07-23 21:06 ` [PATCH 16/23] cxl/core: Convert decoder range to resource Ben Widawsky
2021-07-23 21:06 ` [PATCH 17/23] cxl/region: Handle region's address space allocation Ben Widawsky
2021-07-23 21:06 ` [PATCH 18/23] cxl/region: Only allow CXL capable targets Ben Widawsky
2021-07-23 21:06 ` [PATCH 19/23] cxl/mem: Introduce CXL mem driver Ben Widawsky
2021-07-23 21:06 ` [PATCH 20/23] cxl/memdev: Determine CXL.mem capability Ben Widawsky
2021-07-23 21:06 ` [PATCH 21/23] cxl/mem: Check that the device is CXL.mem capable Ben Widawsky
2021-07-23 21:06 ` [PATCH 22/23] cxl/mem: Add device as a port Ben Widawsky
2021-07-23 21:06 ` [PATCH 23/23] cxl/core: Map component registers for ports Ben Widawsky

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAPcyv4hoUWj_4cDMRszoz5ZcsUBGXE=jX9E5khE=3x97GxJJ7w@mail.gmail.com' \
    --to=dan.j.williams@intel.com \
    --cc=Jonathan.Cameron@huawei.com \
    --cc=alison.schofield@intel.com \
    --cc=ben.widawsky@intel.com \
    --cc=ira.weiny@intel.com \
    --cc=linux-cxl@vger.kernel.org \
    --cc=vishal.l.verma@intel.com \
    --subject='Re: [PATCH 10/23] cxl/decoder: Support parentless decoders' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).