From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 65BA1FCC074 for ; Sun, 8 Mar 2026 14:13:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DBB5710E42C; Sun, 8 Mar 2026 14:13:30 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; secure) header.d=posteo.de header.i=@posteo.de header.b="phk0fw+J"; dkim-atps=neutral Received: from mout02.posteo.de (mout02.posteo.de [185.67.36.66]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8919A10E180 for ; Fri, 6 Mar 2026 20:46:22 +0000 (UTC) Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 9396D240101 for ; Fri, 6 Mar 2026 21:46:20 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1772829980; bh=2iaC+pQxbZxpQoXRMUqKToJTmZXkRZTNoMlTI0V8Hnw=; h=Message-ID:Subject:From:To:Cc:Date:Autocrypt:Content-Type: MIME-Version:OpenPGP:From; b=phk0fw+J2DkqY919TIIAsyR+a+Rtz4/lr1nuk/ouG3opB6VJdC8rzSClPyt+8vQN4 i1JBf/paRzFBWcL3jwYwhValdnSWIqcm/1jFQSPNh0LQZ0dcHz0xXganj1ZGKOC9On 0uEyYF0rZz9miXFNJiWl65+O91yLCTdcFfLo4jF/WDlAxCWDCPYqKSX/x5eXJsFgdl 5PObe5/dzLfp+N3MZER89yroJWHeGlYy/u+aJiDAcx7Nwkbymz9c2H5vUrocePsg6H NoDUpfYqG2M/iv/eh4huzkktUvkkgEjmPWqhld0A0VCfVMvhfUNuViCgn0AZsnlTFI RmM+pU8lnW/7w== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4fSJN963Qyz6twG; Fri, 6 Mar 2026 21:46:17 +0100 (CET) Message-ID: Subject: Re: [PATCH v2 3/4] rust: add basic serial device bus abstractions From: Markus Probst To: Danilo Krummrich Cc: Rob Herring , Greg Kroah-Hartman , Jiri Slaby , Miguel Ojeda , Gary Guo , =?ISO-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Kari Argillander , "Rafael J. Wysocki" , Viresh Kumar , Boqun Feng , David Airlie , Simona Vetter , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-pm@vger.kernel.org, driver-core@lists.linux.dev, dri-devel@lists.freedesktop.org Date: Fri, 06 Mar 2026 20:46:19 +0000 In-Reply-To: References: <20260306-rust_serdev-v2-0-e9b23b42b255@posteo.de> <20260306-rust_serdev-v2-3-e9b23b42b255@posteo.de> Autocrypt: addr=markus.probst@posteo.de; prefer-encrypt=mutual; keydata=mQINBGiDvXgBEADAXUceKafpl46S35UmDh2wRvvx+UfZbcTjeQOlSwKP7YVJ4JOZrVs93 qReNLkOWguIqPBxR9blQ4nyYrqSCV+MMw/3ifyXIm6Pw2YRUDg+WTEOjTixRCoWDgUj1nOsvJ9tVA m76Ww+/pAnepVRafMID0rqEfD9oGv1YrfpeFJhyE2zUw3SyyNLIKWD6QeLRhKQRbSnsXhGLFBXCqt 9k5JARhgQof9zvztcCVlT5KVvuyfC4H+HzeGmu9201BVyihJwKdcKPq+n/aY5FUVxNTgtI9f8wIbm fAjaoT1pjXSp+dszakA98fhONM98pOq723o/1ZGMZukyXFfsDGtA3BB79HoopHKujLGWAGskzClwT jRQxBqxh/U/lL1pc+0xPWikTNCmtziCOvv0KA0arDOMQlyFvImzX6oGVgE4ksKQYbMZ3Ikw6L1Rv1 J+FvN0aNwOKgL2ztBRYscUGcQvA0Zo1fGCAn/BLEJvQYShWKeKqjyncVGoXFsz2AcuFKe1pwETSsN 6OZncjy32e4ktgs07cWBfx0v62b8md36jau+B6RVnnodaA8++oXl3FRwiEW8XfXWIjy4umIv93tb8 8ekYsfOfWkTSewZYXGoqe4RtK80ulMHb/dh2FZQIFyRdN4HOmB4FYO5sEYFr9YjHLmDkrUgNodJCX CeMe4BO4iaxUQARAQABtCdNYXJrdXMgUHJvYnN0IDxtYXJrdXMucHJvYnN0QHBvc3Rlby5kZT6JAl QEEwEIAD4CGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AWIQSCdBjE9KxY53IwxHM0dh/4561 D0gUCaIZ9HQIZAQAKCRA0dh/4561D0pKmD/92zsCfbD+SrvBpNWtbit7J9wFBNr9qSFFm2n/65qen NNWKDrCzDsjRbALMHSO8nigMWzjofbVjj8Nf7SDcdapRjrMCnidS0DuW3pZBo6W0sZqV/fLx+AzgQ 7PAr6jtBbUoKW/GCGHLLtb6Hv+zjL17KGVO0DdQeoHEXMa48mJh8rS7VlUzVtpbxsWbb1wRZJTD88 ALDOLTWGqMbCTFDKFfGcqBLdUT13vx706Q29wrDiogmQhLGYKc6fQzpHhCLNhHTl8ZVLuKVY3wTT+ f9TzW1BDzFTAe3ZXsKhrzF+ud7vr6ff9p1Zl+Nujz94EDYHi/5Yrtp//+N/ZjDGDmqZOEA86/Gybu 6XE/v4S85ls0cAe37WTqsMCJjVRMP52r7Y1AuOONJDe3sIsDge++XFhwfGPbZwBnwd4gEVcdrKhnO ntuP9TvBMFWeTvtLqlWJUt7n8f/ELCcGoO5acai1iZ59GC81GLl2izObOLNjyv3G6hia/w50Mw9MU dAdZQ2MxM6k+x4L5XeysdcR/2AydVLtu2LGFOrKyEe0M9XmlE6OvziWXvVVwomvTN3LaNUmaINhr7 pHTFwDiZCSWKnwnvD2+jA1trKq1xKUQY1uGW9XgSj98pKyixHWoeEpydr+alSTB43c3m0351/9rYT TTi4KSk73wtapPKtaoIR3rOFHLQXbWFya3VzLnByb2JzdEBwb3N0ZW8uZGWJAlEEEwEIADsWIQSCd BjE9KxY53IwxHM0dh/4561D0gUCaIO9eAIbAwULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgAAKCR A0dh/4561D0oHZEACEmk5Ng9+OXoVxJJ+c9slBI2lYxyBO84qkWjoJ/0GpwoHk1IpyL+i+kF1Bb7y Hx9Tiz8ENYX7xIPTZzS8hXs1ksuo76FQUyD6onA/69xZIrYZ0NSA5HUo62qzzMSZL7od5e12R6OPR lR0PIuc4ecOGCEq3BLRPfZSYrL54tiase8HubXsvb6EBQ8jPI8ZUlr96ZqFEwrQZF/3ihyV6LILLk geExgwlTzo5Wv3piOXPTITBuzuFhBJqEnT25q2j8OumGQ+ri8oVeAzx24g1kc11pwpR0sowfa5MvZ WrrBcaIL7uJfR/ig7FyGnTQ1nS3btf3p0v8A3fc4eUu/K2No3l2huJp3+LHhCmpmeykOhSB63Mj3s 3Q87LD0HE0HBkTEMwp+sD97ZRpO67H5shzJRanUaDTb/mREfzpJmRT1uuec0X2zItL7a6itgMJvYI KG29aJLX3fTzzVzFGPgzVZYEdhu4y53p0qEGrrC1JtKR6DRPE1hb/OdWOkjmJ75+PPLD9U5IuRd6y sHJWsEBR1F0wkMPkEofWsvMYJzWXx/rvTWO8N4D6HigTgBXAXNgbc3IHpHlkvKoBJptv6DRVRtIrz 0G0cfBY0Sm7he4N2IYDWWdGnPBZ3rlLSdj5EiBU2YWgIgtLrb8ZNJ3ZlhYluGnBJDGRqy2jC9s1jY 66sLA9rQZMHhJTzMyIDwweGlvMzJAcG9zdGVvLmV1PokCbQQTAQgAVxYhBIJ0GMT0rFjncjDEczR2 H/jnrUPSBQJpa71VGxSAAAAAAAQADm1hbnUyLDIuNSsxLjExLDIsMgIbAwULCQgHAgIiAgYVCgkIC wIEFgIDAQIeBwIXgAAKCRA0dh/4561D0gKJD/9uOQKYlsDoQX65Gd0LiMT0C+5vXgr3VI0PHDOwcv 51fJ3A1vNyPZRFPGrz8+mDEXUQOF/INfnz5Tu1QHwf+iYcWcTGAN/FHgVR6ET6VBNU2hJaKhu+Ggo kjYyJTOvyX+3yNRUfSny0GjTjIPuPTErjqmHF+BtjXslpgwqnNMznf3lRIuUjRORupos6p3k1DndE 5vzUTmXSvMyXyOD2KhBl/kL76k0bHYyAQytZPag12pltrtFbA/r2phDGN2si8PooDT99bSTJjaM45 MTAAHbHKJfvgfK41bNFD5mMtpWpL195XRtS0Nrxdg3PaYBxN5gtTG0RyZfpYRlkdEhm+jj/8RxuSG i/qdhRdbiI7K2IELWeQVHSNDi9JabR/UzlR4NSnhfAjRIVlRM+eFbUl8XwxwVrAkojF5IraH2qRvg VCmuFsHUW07FUlrDrzpjXsD73cKppoFGDCdDR0BHJepXbFLS9+AqkT+guRJlnCTg2p+TQtnbwPgKp Vj98JixovCl99zRYTsL2bRNU5+q8iET65VMJ1ydyNanvLd5vI/NqDkXhlXLsGmdaDTtu4R21PkToX dQNGrZ91M9nlIBKw8Y7c7xZ4098qX2b8JX/CxD+gC1r4C8vuA3GkhFLx+KlkON7LyiJPkrePp6Qky jfGillcaQOqFZ3WwVqyzG1BUfTow== Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-o/KXAoogandmA1L4aMdF" MIME-Version: 1.0 OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt X-Mailman-Approved-At: Sun, 08 Mar 2026 14:13:21 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" --=-o/KXAoogandmA1L4aMdF Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2026-03-06 at 21:40 +0100, Danilo Krummrich wrote: > On Fri Mar 6, 2026 at 8:35 PM CET, Markus Probst wrote: > > + extern "C" fn receive_buf_callback( > > + sdev: *mut bindings::serdev_device, > > + buf: *const u8, > > + length: usize, > > + ) -> usize { > > + // SAFETY: The serial device bus only ever calls the receive b= uf callback with a valid > > + // pointer to a `struct serdev_device`. > > + // > > + // INVARIANT: `sdev` is valid for the duration of `receive_buf= _callback()`. > > + let sdev =3D unsafe { &*sdev.cast::>() }; > > + > > + // SAFETY: `receive_buf_callback` is only ever called after a = successful call to > > + // `probe_callback`, hence it's guaranteed that `Device::set_d= rvdata()` has been called > > + // and stored a `Pin>`. > > + let data =3D unsafe { sdev.as_ref().drvdata_borrow::() }; > > + > > + // SAFETY: > > + // - The serial device bus only ever calls the receive buf cal= lback with a valid pointer to > > + // a `struct serdev_device`. > > + // - `receive_buf_callback` is only ever called after a succes= sful call to > > + // `probe_callback`, hence it's guaranteed that `sdev.privat= e_data` is a pointer > > + // to a valid `PrivateData`. > > + let private_data =3D unsafe { &*(*sdev.as_raw()).private_data.= cast::() }; > > + > > + private_data.probe_complete.complete_all(); >=20 > Will do a full review pass later on, but one quick question in advance: >=20 > What is this used for? It is completed here and in probe(), but I don't s= ee it ever > being used to actually wait. Uh, thats a typo. It is supposed to wait here in receive_buf_callback. Thanks - Markus Probst >=20 > > + > > + // SAFETY: No one has exclusive access to `private_data.error`= . > > + if unsafe { *private_data.error.get() } { > > + return length; > > + } > > + > > + // SAFETY: `buf` is guaranteed to be non-null and has the size= of `length`. > > + let buf =3D unsafe { core::slice::from_raw_parts(buf, length) = }; > > + > > + T::receive(sdev, data, buf) > > + } > > +} --=-o/KXAoogandmA1L4aMdF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQJPBAABCAA5FiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IFAmmrPRcbFIAAAAAABAAO bWFudTIsMi41KzEuMTEsMiwyAAoJEDR2H/jnrUPSWVEP/1ag22PV+effqCIXNtIi ojhUChzfy4ZFNQt7RTYHSrKwzWk0LWTMbCrEH2S818Rbhhwb8xVGLKFOujTKFx/0 RhnYaiCBCa5LmYRcSLIvp4cf9DLR547L9kAIQEbqZ0UaXyINt1sIKm9A17R28Zo8 JKu+Z57BkfSEn65N0E5w9xcHpzlBx7dK1zp0vLCWT/6GM1uXLwJQ5RYIP0ejcVpc xWKbwcLjPY6Wc35tIHOgTW4kJyQOBfNkO7flQn4kZvvnnVqwJz/bVl6TWH93s94H np6fggCna/m1JmOklY4MQVPLnLrDAAOSEWVZTytEXH6gYnOCbpYqwIdKiDrbTQKz Hki4V/ytUtSvoCtsoj53rPqawbTGP1dBCgcnNZwOf64h4HqY1UGqWGfriRFvczB+ DuHAndPRI/doaHzm7u/jXmVKjhHIfq1QByvF5n2JEii0YtqvFFqJ/+IOcQLewugx p8DUTAhPTLsXwfsuy/D4hgfpJVayXdnGxA7L8IUMbFyMnNS+8qwGSn0OkIfZbQIi 1zpi2P2FUwAB+YpEGxoI9r9cDSl0TckIoTny8BZskbzb6ZCZP9mB2Ie095UJbP3s BauRToFJ+KZi67Z8V4ooNgREBKEECBlxxs4aVPCo2lIHvW8aftj2riSq5Gy4hIgD rznZ+gd+0JDfXZFuGhtCi5SM =HjzS -----END PGP SIGNATURE----- --=-o/KXAoogandmA1L4aMdF--