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Sun, 21 Dec 2025 13:41:09 +0100 (CET) Message-ID: <2f42525e678925a803ea4acaeb1e704953e44681.camel@posteo.de> Subject: Re: [PATCH RFC 2/4] rust: add basic serial device bus abstractions From: Markus Probst To: Dirk Behme , Rob Herring , Greg Kroah-Hartman , Jiri Slaby , Miguel Ojeda , Boqun Feng , Gary Guo , =?ISO-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Kari Argillander Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org Date: Sun, 21 Dec 2025 12:41:10 +0000 In-Reply-To: <4c26408c-b8ce-42a6-b0df-47053fd81eda@gmail.com> References: <20251220-rust_serdev-v1-0-e44645767621@posteo.de> <20251220-rust_serdev-v1-2-e44645767621@posteo.de> <4c26408c-b8ce-42a6-b0df-47053fd81eda@gmail.com> 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 66sLA9g== Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-/XVG65cPYd9G6NsyoQIJ" Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt --=-/XVG65cPYd9G6NsyoQIJ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Dirk, On Sun, 2025-12-21 at 10:19 +0100, Dirk Behme wrote: > Hi Markus, >=20 > On 20.12.25 19:44, Markus Probst wrote: > > Implement the basic serial device bus abstractions required to write a > > serial device bus device driver with or without the need for initial de= vice > > data. This includes the following data structures: > >=20 > > The `serdev::Driver` trait represents the interface to the driver. > >=20 > > The `serdev::Device` abstraction represents a `struct serdev_device`. > >=20 > > In order to provide the Serdev specific parts to a generic > > `driver::Registration` the `driver::RegistrationOps` trait is > > implemented by `serdev::Adapter`. > >=20 > > Co-developed-by: Kari Argillander > > Signed-off-by: Kari Argillander > > Signed-off-by: Markus Probst > > --- > > rust/bindings/bindings_helper.h | 1 + > > rust/helpers/helpers.c | 1 + > > rust/helpers/serdev.c | 22 ++ > > rust/kernel/lib.rs | 2 + > > rust/kernel/serdev.rs | 815 ++++++++++++++++++++++++++++++++= ++++++++ > > 5 files changed, 841 insertions(+) > >=20 > ... > > diff --git a/rust/kernel/serdev.rs b/rust/kernel/serdev.rs > > new file mode 100644 > > index 000000000000..0f5ef325a054 > > --- /dev/null > > +++ b/rust/kernel/serdev.rs > .... > > + /// Write data to the serial device until the controller has accep= ted all the data or has > > + /// been interrupted by a timeout or signal. > > + /// > > + /// Note that any accepted data has only been buffered by the cont= roller. Use > > + /// [ Device::wait_until_sent`] to make sure the controller write = buffer has actually been > > + /// emptied. > > + /// > > + /// Returns the number of bytes written (less than data if interru= pted). >=20 > Should it be "less than data.len"? Instead of just "data"? Same in the > comment for `write()`below. Yes. >=20 >=20 > > + /// [`kernel::error::code::ETIMEDOUT`] or [`kernel::error::code::E= RESTARTSYS`] if interrupted > > + /// before any bytes were written. > > + pub fn write_all(&self, data: &[u8], timeout: Timeout) -> Result { > > + // SAFETY: > > + // - `self.as_raw()` is guaranteed to be a pointer to a valid = `serdev_device`. > > + // - `data.as_ptr()` is guaranteed to be a valid array pointer= with the size of > > + // `data.len()`. > > + let ret =3D unsafe { > > + bindings::serdev_device_write( > > + self.as_raw(), > > + data.as_ptr(), > > + data.len(), > > + timeout.into_jiffies(), > > + ) > > + }; > > + if ret < 0 { > > + // CAST: negative return values are guaranteed to be betwe= en `-MAX_ERRNO` and `-1`, > > + // which always fit into a `i32`. > > + Err(Error::from_errno(ret as i32)) > > + } else { > > + Ok(ret.unsigned_abs()) > > + } > > + } > > + > > + /// Write data to the serial device. > > + /// > > + /// If you want to write until the controller has accepted all the= data, use > > + /// [`Device::write_all`]. > > + /// > > + /// Note that any accepted data has only been buffered by the cont= roller. Use > > + /// [ Device::wait_until_sent`] to make sure the controller write = buffer has actually been > > + /// emptied. > > + /// > > + /// Returns the number of bytes written (less than data if interru= pted). > > + /// [`kernel::error::code::ETIMEDOUT`] or [`kernel::error::code::E= RESTARTSYS`] if interrupted > > + /// before any bytes were written. > > + pub fn write(&self, data: &[u8]) -> Result { > > + // SAFETY: > > + // - `self.as_raw()` is guaranteed to be a pointer to a valid = `serdev_device`. > > + // - `data.as_ptr()` is guaranteed to be a valid array pointer= with the size of > > + // `data.len()`. > > + let ret =3D > > + unsafe { bindings::serdev_device_write_buf(self.as_raw(), = data.as_ptr(), data.len()) }; > > + if ret < 0 { > > + Err(Error::from_errno(ret)) > > + } else { > > + Ok(ret.unsigned_abs()) > > + } > > + } >=20 > Best regards >=20 > Dirk Thanks - Markus Probst --=-/XVG65cPYd9G6NsyoQIJ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQJPBAABCAA5FiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IFAmlH6uUbFIAAAAAABAAO bWFudTIsMi41KzEuMTEsMiwyAAoJEDR2H/jnrUPSKzwP/jRVFU10i5GjfwhXNi7L mNYrRiM1KRkacuJrAc4MknRGzn3C0KmgLTKMLvA2+P4Uei41Mo68buR1fuuFG98c 9O42GBuOgcj/OJ2AWqynp83pIy2Dbt4GCnmgTOxKQe2r4mNgyPM2trWdc1Y0EJqJ aKy4jq+ZoX89RYN3gmbc13uvme6cBxkm7igHrPCE1kTDAqr+h4FcvWP+Z5aHGo2A ialZJqEyh+Xwzoun7YjuTiGwUfbfXCvB5n0VyO5iIswY2oDgOBemI89ZrfLQcf3V h3SMtZdzrzQ6C2pTDWwLmve/++HkqFgBqeek4RGEUgm6Dni27v1oWMsXyWvqOB2y qQVZKltS13OPmOunTCBuHgCSEfYBWRUGuZVhYDWOUNWOELaZLGFrrhpfZ1IJZOtv HSn+yHyqUzrSnptNE8aDG/lAy6ZBsWvr2LGtGdJIPl3QfidkOQ4CH8E56p3ykrfR G5pUwV6lTXtAj6RheQP62FgeZwwMn0T35yGa1GSGqpKeRYTvK44nDF1dCUSaYjHl MwY1meFU8NkZBXe5CA6azbqk9UIX30kl+8LKZSeMRWLKSm9dzu+wlNayeZdvl/hn 7P2xSWkIT4yylvgq0v6G+l/yptafxcLoSdt1Lmge5tXuYbeLntYlK9BCibkp+W/X 04yfGlkxSinXCKfHrzNnzOxE =93Qy -----END PGP SIGNATURE----- --=-/XVG65cPYd9G6NsyoQIJ--