From nobody Fri Dec 19 12:46:35 2025 Received: from mout-p-201.mailbox.org (mout-p-201.mailbox.org [80.241.56.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E1236289E17; Tue, 20 May 2025 20:01:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747771275; cv=none; b=pKT2Fai6JygW/f8A/lvNF3ZGpMZ21ihpiwGWeyhdNLgXlVzounlV5H/V282e0A+Ns2vQp3kbNWpcy4rmbuAGndK9DV3hDoz4dW7ywcq/+LJNQurhIM35T2IzY3+EL7J/7BNiJGJG1OJ0Do7PtO/LOI0li6Bgh6Pi1xusAfDqkas= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747771275; c=relaxed/simple; bh=AjbI7tXF1FTZLMO6RR+FWGb96M8qcqTNYqu7i3vrx1g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rmU6O9LNAkj/G6RoPY2CH6yOnL14/T1Sz3lmFCm9uSBAGdir4NJ8NUkAQd55jcbRoaEKOFCTeIXJQtaVYVLJ3y2kRpaMomeJ+ID9kcUtn6lYKwtowQZTxCWCu0Y9r2wFyL6VccJjXGXXCirXP8Ka+Ok+wsbfIP7OZ6UeQG7YeXY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=buenzli.dev; spf=pass smtp.mailfrom=buenzli.dev; arc=none smtp.client-ip=80.241.56.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=buenzli.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=buenzli.dev Received: from smtp102.mailbox.org (smtp102.mailbox.org [10.196.197.102]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 4b255r4QJJz9std; Tue, 20 May 2025 22:01:04 +0200 (CEST) From: Remo Senekowitsch To: Rob Herring , Saravana Kannan , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Dirk Behme , Remo Senekowitsch Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, rust-for-linux@vger.kernel.org Subject: [PATCH v5 8/9] rust: device: Add property_get_reference_args Date: Tue, 20 May 2025 22:00:23 +0200 Message-ID: <20250520200024.268655-9-remo@buenzli.dev> In-Reply-To: <20250520200024.268655-1-remo@buenzli.dev> References: <20250520200024.268655-1-remo@buenzli.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Allow Rust code to read reference args from device properties. The wrapper type `FwNodeReferenceArgs` allows callers to access the buffer of read args safely. Signed-off-by: Remo Senekowitsch --- rust/kernel/device/property.rs | 68 ++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/rust/kernel/device/property.rs b/rust/kernel/device/property.rs index 0365c91a2e5b9..510903473695e 100644 --- a/rust/kernel/device/property.rs +++ b/rust/kernel/device/property.rs @@ -291,6 +291,65 @@ pub fn children<'a>(&'a self) -> impl Iterator> + 'a { Some(next) }) } + + /// Finds a reference with arguments. + pub fn property_get_reference_args( + &self, + prop: &CStr, + nargs: NArgs<'_>, + index: u32, + ) -> Result { + let mut out_args =3D FwNodeReferenceArgs::default(); + + let (nargs_prop, nargs) =3D match nargs { + NArgs::Prop(nargs_prop) =3D> (nargs_prop.as_char_ptr(), 0), + NArgs::N(nargs) =3D> (ptr::null(), nargs), + }; + + // SAFETY: `self.0.get()` is valid. `prop.as_char_ptr()` is valid = and + // zero-terminated. `nargs_prop` is valid and zero-terminated if `= nargs` + // is zero, otherwise it is allowed to be a null-pointer. + let ret =3D unsafe { + bindings::fwnode_property_get_reference_args( + self.0.get(), + prop.as_char_ptr(), + nargs_prop, + nargs, + index, + &mut out_args.0, + ) + }; + to_result(ret)?; + + Ok(out_args) + } +} + +/// The return value of `property_get_reference_args`. +/// +/// - [`Device::property_get_reference_args`] +/// - [`FwNode::property_get_reference_args`] +#[repr(transparent)] +#[derive(Copy, Clone, Default)] +pub struct FwNodeReferenceArgs(bindings::fwnode_reference_args); + +impl FwNodeReferenceArgs { + /// Returns the slice of reference arguments. + pub fn as_slice(&self) -> &[u64] { + // SAFETY: As per the safety invariant of FwNodeReferenceArgs, `na= rgs` + // is the number of elements in `args` that is valid. + unsafe { core::slice::from_raw_parts(self.0.args.as_ptr(), self.0.= nargs as usize) } + } + + /// Returns the number of reference arguments. + pub fn len(&self) -> usize { + self.0.nargs as usize + } + + /// Returns `true` if there are no reference arguments. + pub fn is_empty(&self) -> bool { + self.0.nargs =3D=3D 0 + } } =20 // SAFETY: Instances of `FwNode` are always reference-counted. @@ -450,6 +509,15 @@ fn read_from_fwnode_property(fwnode: &FwNode, name: &C= Str) -> Result { i64: fwnode_property_read_u64_array, } =20 +/// The number of arguments of a reference. +pub enum NArgs<'a> { + /// The name of the property of the reference indicating the number of + /// arguments. + Prop(&'a CStr), + /// The known number of arguments. + N(u32), +} + /// A helper for reading device properties. /// /// Use [`Self::required_by`] if a missing property is considered a bug and --=20 2.49.0