Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   "Kubalewski, Arkadiusz" <arkadiusz.kubalewski@intel.com>
To:     Jiri Pirko <jiri@resnulli.us>, Jakub Kicinski <kuba@kernel.org>
CC:     "vadfed@meta.com" <vadfed@meta.com>,
        "jonathan.lemon@gmail.com" <jonathan.lemon@gmail.com>,
        "pabeni@redhat.com" <pabeni@redhat.com>,
        "corbet@lwn.net" <corbet@lwn.net>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "edumazet@google.com" <edumazet@google.com>,
        "vadfed@fb.com" <vadfed@fb.com>,
        "Brandeburg, Jesse" <jesse.brandeburg@intel.com>,
        "Nguyen, Anthony L" <anthony.l.nguyen@intel.com>,
        "M, Saeed" <saeedm@nvidia.com>,
        "leon@kernel.org" <leon@kernel.org>,
        "richardcochran@gmail.com" <richardcochran@gmail.com>,
        "sj@kernel.org" <sj@kernel.org>,
        "javierm@redhat.com" <javierm@redhat.com>,
        "ricardo.canuelo@collabora.com" <ricardo.canuelo@collabora.com>,
        "mst@redhat.com" <mst@redhat.com>,
        "tzimmermann@suse.de" <tzimmermann@suse.de>,
        "Michalik, Michal" <michal.michalik@intel.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "jacek.lawrynowicz@linux.intel.com" 
        <jacek.lawrynowicz@linux.intel.com>,
        "airlied@redhat.com" <airlied@redhat.com>,
        "ogabbay@kernel.org" <ogabbay@kernel.org>,
        "arnd@arndb.de" <arnd@arndb.de>,
        "nipun.gupta@amd.com" <nipun.gupta@amd.com>,
        "axboe@kernel.dk" <axboe@kernel.dk>,
        "linux@zary.sk" <linux@zary.sk>,
        "masahiroy@kernel.org" <masahiroy@kernel.org>,
        "benjamin.tissoires@redhat.com" <benjamin.tissoires@redhat.com>,
        "geert+renesas@glider.be" <geert+renesas@glider.be>,
        "Olech, Milena" <milena.olech@intel.com>,
        "kuniyu@amazon.com" <kuniyu@amazon.com>,
        "liuhangbin@gmail.com" <liuhangbin@gmail.com>,
        "hkallweit1@gmail.com" <hkallweit1@gmail.com>,
        "andy.ren@getcruise.com" <andy.ren@getcruise.com>,
        "razor@blackwall.org" <razor@blackwall.org>,
        "idosch@nvidia.com" <idosch@nvidia.com>,
        "lucien.xin@gmail.com" <lucien.xin@gmail.com>,
        "nicolas.dichtel@6wind.com" <nicolas.dichtel@6wind.com>,
        "phil@nwl.cc" <phil@nwl.cc>,
        "claudiajkang@gmail.com" <claudiajkang@gmail.com>,
        "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "intel-wired-lan@lists.osuosl.org" <intel-wired-lan@lists.osuosl.org>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>, poros <poros@redhat.com>,
        mschmidt <mschmidt@redhat.com>,
        "linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>,
        "vadim.fedorenko@linux.dev" <vadim.fedorenko@linux.dev>
Subject: RE: [RFC PATCH v8 01/10] dpll: documentation on DPLL subsystem
 interface
Thread-Topic: [RFC PATCH v8 01/10] dpll: documentation on DPLL subsystem
 interface
Thread-Index: AQHZmszoYeH83BxaW02EVqODRhjpgq+HyQOAgAC7rICAAHCNgIABGgiAgAAa0HA=
Date:   Wed, 14 Jun 2023 12:21:29 +0000
Message-ID: <DM6PR11MB465799A5A9BB0B8E73A073449B5AA@DM6PR11MB4657.namprd11.prod.outlook.com>
References: <20230609121853.3607724-1-arkadiusz.kubalewski@intel.com>
 <20230609121853.3607724-2-arkadiusz.kubalewski@intel.com>
 <20230612154329.7bd2d52f@kernel.org> <ZIg8/0UJB9Lbyx2D@nanopsycho>
 <20230613093801.735cd341@kernel.org> <ZImH/6GzGdydC3U3@nanopsycho>
In-Reply-To: <ZImH/6GzGdydC3U3@nanopsycho>
Accept-Language: pl-PL, en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?CQpz9DIX3FVTzO40Pha6iEnBS1P9r3vA+UaVyO4SSZ0nReqb9vXpe+26e+qH?=
 =?us-ascii?Q?UvoaMN9PSn8UMAzeirj/VMqdU6+r5BSKIVeL0pvzT4E6ePVQIVwpbqNB9yr8?=
 =?us-ascii?Q?CsuPDWkL/9HDSJPVjsAFP6Vm6aCbDHDaehVvxsJ+BQx0LHmQ0tDVo5AHw6mp?=
 =?us-ascii?Q?FQvOGmM+xqOO2kuIKsQoc1wSVZOFV4G3HUjwpZYKjaZW+2fxljd4Wd7YOqRo?=
 =?us-ascii?Q?90G/9qtnccVp1QoneyC4x8up5oa6M8D158HJcGAaU+F6OZgGF7ciRwyEwRLV?=
 =?us-ascii?Q?V50H8qPNNV2QajWZ3ppz9UmW6PhKQVMUYPwclMT74TsIIW4nbC5A4Cyd0CXC?=
 =?us-ascii?Q?xoJzMiEWoqbJJqZ9E4/XT5UW8sAgbCIYogWTEOAud4VTCiRPfORlIbUlhXho?=
 =?us-ascii?Q?JJOcalFGi9zvh0WzlzjD6cFzoz7EQhZR8mlrMn7zx0C6Qh0r0uY5iKEN889w?=
 =?us-ascii?Q?KuOB/HDKxELtOyJbCU1jMc0U/5ARM5wjTpfkxAH57VxLQoHtpHrBFohbWPgo?=
 =?us-ascii?Q?s+CDfVhqrvgRWD9zSVrPL2UMNDZ7JSSIjgxULq8TgqtOwX24YpsCG8gjG5Qo?=
 =?us-ascii?Q?8VhGSnLncUH+XpcW9cA9BqgCQhHDveNSLC6PMXrqecZqytSSkis5qLzj7pk8?=
 =?us-ascii?Q?+DQmxEX2pqzE16q5rVcgta0PTxfY0GH0Y1fkpL7F/h53FV4TyJzBGUxVlCLf?=
 =?us-ascii?Q?zZ23w8M6ROuxt3jmAbMZA8105fvUHADtIdk74rqH9V8d4tHMENgvT6dWEA3y?=
 =?us-ascii?Q?8OWJ2ylQfUUX+SLuYepAxlJ7O/YxuMZPDnovAaGPt6psmrYYt+kWWRthbxOn?=
 =?us-ascii?Q?lNwEhuvFyFIykWeliv+hs8szDYemTbUo1Yvk9vYOLm4C8fQ4UhsTzHbKdYqj?=
 =?us-ascii?Q?QY2aeqvGcS7495QIVHkqftqs+irR+C1KQjJ+n/TgMcrW0zfgC7YvWGAjgs28?=
 =?us-ascii?Q?MzaKgwWDlIqaxfO0fWmkC7tZ1jiwSOCq741eacsKKsUtuTexahqHMsUiqeTq?=
 =?us-ascii?Q?985e4zv7Yl6QshniO3/mhNpb1VhfGSuG2xGPmJrZ4tr/MCLZZ9RCU0TO6Mqw?=
 =?us-ascii?Q?1avHpDSAKwTLi+Wy02reuN1yGEZ5RHADP8aqWfX7dUrZTDj56ApI4ZRnyE2O?=
 =?us-ascii?Q?TueAWL1HtmEQi8juzY1vkXgMyi31/PcDNcck57u3MuL4hRdjkb9cIIk6R1vN?=
 =?us-ascii?Q?CvfIkCtafescHSruukJ27qXSqTOsKIIF6QtZEny/NrazQt72tADj+vY4Tgw8?=
 =?us-ascii?Q?sP/fnqD7tdtg4RjcARKCZcevhYLO0aUNECHOy0hjJt5y4WVv6wILVGnsfGlv?=
 =?us-ascii?Q?iw4wvonJCrOgBTlxsXz4APkVSPAqAkOD82A1EM2ZMK060I+dnDQ9GhTN39jK?=
 =?us-ascii?Q?zvei9mK2+FNpXpKgkOf3h3YEVKjmvM6/452vbkwL1Ykyb5g07ojFN+hE586O?=
 =?us-ascii?Q?G9dLZzVxmbUrPvxQ7SDdNTvT85tCs5yHTr5V3G96xcZRKIih7SRdDnpRLNK9?=
 =?us-ascii?Q?gI89HcI6KoIea2q4PhoMGT7AABFvpTPnbHD51YhX5puGhOumWND7aF+Lj9Yq?=
 =?us-ascii?Q?xxKEY3z7mOcnF2/F7rPxoKC8HG8Z+MkMsf66JEC11X43Kxc5N+6cmghz4GZi?=
 =?us-ascii?Q?Rg=3D=3D?=
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: DM6PR11MB4657.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: f0b35c82-0ea3-4325-bf06-08db6cd1e1c6
X-MS-Exchange-CrossTenant-originalarrivaltime: 14 Jun 2023 12:21:29.4752
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: 1dJdcOamgTJzDk35+9p4WjDIVAn0C9f11hmRmAtcI3ujO6N2jSkT5KvZEGXZw/7ZeHQ5TRWoijhaan6B+MH1fSdWu2x1l92ZpF4X4tk9Dmw=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR11MB5796
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,
        SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED
        autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

>From: Jiri Pirko <jiri@resnulli.us>
>Sent: Wednesday, June 14, 2023 11:27 AM
>
>Tue, Jun 13, 2023 at 06:38:01PM CEST, kuba@kernel.org wrote:
>>On Tue, 13 Jun 2023 11:55:11 +0200 Jiri Pirko wrote:
>>> >> +``'pin': [{
>>> >> + {'clock-id': 282574471561216,
>>> >> +  'module-name': 'ice',
>>> >> +  'pin-dpll-caps': 4,
>>> >> +  'pin-id': 13,
>>> >> +  'pin-parent': [{'pin-id': 2, 'pin-state': 'connected'},
>>> >> +                 {'pin-id': 3, 'pin-state': 'disconnected'},
>>> >> +                 {'id': 0, 'pin-direction': 'input'},
>>> >> +                 {'id': 1, 'pin-direction': 'input'}],
>>> >> +  'pin-type': 'synce-eth-port'}
>>> >> +}]``
>>> >
>>> >It seems like pin-parent is overloaded, can we split it into two
>>> >different nests?
>>>
>>> Yeah, we had it as two and converged to this one. The thing is, the res=
t
>>> of the attrs are the same for both parent pin and parent device. I link
>>> it this way a bit better. No strong feeling.
>>
>>Do you mean the same attribute enum / "space" / "set"?
>
>Yeah, that is my understanding. Arkadiusz, could you please clarify?
>

From user perspective the pin object is configured either:
- by itself (DPLL_A_PIN_FREQUENCY), as this affects all registered pin's dp=
lls=20
and frequency set ops are called on all of them,
- in a tuples, where ops are called only on particular parent object:
  - pin:'dpll device' (DPLL_A_PIN_STATE, DPLL_A_PIN_PRIO, DPLL_A_PIN_DIRECT=
ION),
  - pin:'parent MUX-type pin' (DPLL_A_PIN_STATE).
 =20
Right now DPLL_A_PIN_PARENT nest can convey both parent types:
- if the nest contains DPLL_A_ID, other attributes describe config with the
parent dpll device,
- if it contains DPLL_A_PIN_ID, the other attributes describe config with t=
he
parent pin.

The above example is actually a bit misleading, as this relates to the muxe=
d
pin. From user perspective the information on parent dpll devices is redund=
ant,
and I think in this case we shall not pass it to the user, as the pin was n=
ot
explicitly registered with a device by device driver.
The user shall only get parent pin related info, like:
``'pin': [{
 {'clock-id': 282574471561216,
  'module-name': 'ice',
  'pin-dpll-caps': 4,
  'pin-id': 13,
  'pin-parent': [{'pin-id': 2, 'pin-state': 'connected'},
                 {'pin-id': 3, 'pin-state': 'disconnected'},
  'pin-type': 'synce-eth-port'}
}]``

Thus will fix this by removing the parent device information from the muxed
pins info.

But to answer the question: for now it seems good enough to have the PIN_PA=
RENT
nest that conveys either parent pin or parent dpll device information.
IMHO the real question here is about the future, are we going to add pin-pa=
rent
only config, which would not be a part of pin-device superset and would mak=
e
things unclear?
Unfortunately I don't have on my mind anything more that would be needed fo=
r
pin:parent_pin tuple..

Surely, we can skip this discussion and split the nest attr into something =
like:
- PIN_A_PIN_PARENT_DEVICE,
- PIN_A_PIN_PARENT_PIN.

>
>>In the example above the attributes present don't seem to overlap.
>>For user space its an extra if to sift thru the objects under
>>pin-parent.
>>
>>> >Also sounds like setting pin attrs and pin-parent attrs should be
>>> >different commands.
>>>
>>> Could be, but what't the benefit? Also, you are not configuring
>>> pin-parent. You are configuring pin:pin-parent tuple. Basically the pin
>>> configuration as a child. So this is mainly config of the pin itsest
>>> Therefore does not really make sense to me to split to two comments.
>>
>>Clarity of the API. If muxing everything thru few calls was the goal
>>we should also have very few members in struct dpll_pin_ops, and we
>>don't.
>
>How the the internal kernel api related to the uapi? I mean, it's quite
>common to have 1:N relationsip between cmd and op. I have to be missing
>your point. Could you be more specific please?
>
>Current code presents PIN_SET command with accepts structured set of
>attribute to be set. The core-driver api is pretty clear. Squashing to
>a single op would be disaster. Having one command per attr looks like an
>overkill without any real benefit. How exactly do you propose to change
>this?

Well, I agree that one command per attribute might be an overkill.

Thank you,
Arkadiusz