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...
next prev parent 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
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