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] cxl: Enable an endpoint decoder type
Date: Fri, 13 Aug 2021 18:10:59 -0700 [thread overview]
Message-ID: <CAPcyv4hcZVKmvpGMwF+QH8aLCWd16Rh5a4BU74=YdmNoC1716A@mail.gmail.com> (raw)
In-Reply-To: <20210702040009.68794-1-ben.widawsky@intel.com>
On Thu, Jul 1, 2021 at 9:00 PM Ben Widawsky <ben.widawsky@intel.com> wrote:
>
> CXL memory devices support HDM decoders. Currently, when a decoder is
> instantiated there is no knowledge of the type of decoder; only the
> underlying endpoint type is specified. In order to have the memory
> devices reuse the existing decoder creation infrastructure it is
> convenient to pass along the type of decoder on creation.
>
> The primary difference for an endpoint decoder is that it doesn't have
> dports, nor targets. The target is just the underlying media (with
> offset).
>
It's been a while, can you redo this patch just focusing on how to
represent an endpoint without redoing the typing for existing
decoders? It's not clear that cxl_decoder_type needs any updates. An
endpoint decoder is either accelerator or expander (2 or 3). What
makes an endpoint is merely that it is terminal in the sysfs decode
topology. Just like the difference between root decoders and switch
decoders is that root ones are origins of a decode hierarchy. You
identify root decoders by the parent port type and endpoints by the
lack of a target_map.
Yes, target_map is a recent addition, but it seems to naturally fit
the endpoint decoder definition since the target list is replaced with
DPA Skip Low on endpoints.
In short I don't think any new type information is needed, it can all
be inferred inside devm_cxl_add_decoder().
prev parent reply other threads:[~2021-08-14 1:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-02 4:00 [PATCH] cxl: Enable an endpoint decoder type Ben Widawsky
2021-07-06 16:00 ` [PATCH v2] " Ben Widawsky
2021-07-09 23:56 ` Dan Williams
2021-07-16 23:37 ` Ben Widawsky
2021-07-17 22:18 ` Dan Williams
2021-07-20 23:43 ` Ben Widawsky
2021-07-26 18:12 ` Dan Williams
2021-08-14 1:10 ` Dan Williams [this message]
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