From nobody Sat Oct 11 08:30:55 2025 Received: from mout-p-103.mailbox.org (mout-p-103.mailbox.org [80.241.56.161]) (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 C1A9A267B65; Wed, 11 Jun 2025 10:29:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.161 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749637794; cv=none; b=Uyt82cjYZav4BoPWpc1cvyVmSZPDxLo0/3RGxW2RBUy+zuCUk+YMIPO8f+TanQPw/YaYnQI6ZdZx/iGLL3FID3m448Ge4n7HOt6STllR5rLtP1CX1EesDH+TyWzvnoLhqyjTUlxFlkokE5Cv5i+XYsblot3gXbDvDRjiCMiYRHQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749637794; c=relaxed/simple; bh=2BoW4pFaIctzE8BFvVPtU04cbrv4X3tZKXfOo1/sW/A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Tk5/L0RIYom1zuGltXpUAkV5SX/lSy94H9aZt3zvjgm9CkC4EYjrQIeea5uMcfFMvFam847oGdqi1ARbjzwQhYBbt0AFaNXPFzdTYmb/D+pJMtU55QUh38zYGQVaIb32xRhtlpCfZxJgcXAqQlj1UpQhg8M5pwOb64ueNi2lAdY= 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=80.241.56.161 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 smtp202.mailbox.org (smtp202.mailbox.org [IPv6:2001:67c:2050:b231:465::202]) (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-103.mailbox.org (Postfix) with ESMTPS id 4bHMNR0zGNz9tKs; Wed, 11 Jun 2025 12:29:43 +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 v8 4/9] rust: device: Enable printing fwnode name and path Date: Wed, 11 Jun 2025 12:29:03 +0200 Message-ID: <20250611102908.212514-5-remo@buenzli.dev> In-Reply-To: <20250611102908.212514-1-remo@buenzli.dev> References: <20250611102908.212514-1-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 X-Rspamd-Queue-Id: 4bHMNR0zGNz9tKs Content-Type: text/plain; charset="utf-8" Add two new public methods `display_name` and `display_path` to `FwNode`. They can be used by driver authors for logging purposes. In addition, they will be used by core property abstractions for automatic logging, for example when a driver attempts to read a required but missing property. Tested-by: Dirk Behme Signed-off-by: Remo Senekowitsch --- rust/kernel/device/property.rs | 76 ++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/rust/kernel/device/property.rs b/rust/kernel/device/property.rs index 50c61aa056e6b..4cac335bad78c 100644 --- a/rust/kernel/device/property.rs +++ b/rust/kernel/device/property.rs @@ -57,6 +57,32 @@ pub(crate) fn as_raw(&self) -> *mut bindings::fwnode_han= dle { self.0.get() } =20 + /// Returns an object that implements [`Display`](core::fmt::Display) = for + /// printing the name of a node. + /// + /// This is an alternative to the default `Display` implementation, wh= ich + /// prints the full path. + pub fn display_name(&self) -> impl core::fmt::Display + '_ { + struct FwNodeDisplayName<'a>(&'a FwNode); + + impl core::fmt::Display for FwNodeDisplayName<'_> { + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::= Result { + // SAFETY: `self` is valid by its type invariant. + let name =3D unsafe { bindings::fwnode_get_name(self.0.as_= raw()) }; + if name.is_null() { + return Ok(()); + } + // SAFETY: + // - `fwnode_get_name` returns null or a valid C string. + // - `name` was checked to be non-null. + let name =3D unsafe { CStr::from_char_ptr(name) }; + write!(f, "{name}") + } + } + + FwNodeDisplayName(self) + } + /// Checks if property is present or not. pub fn property_present(&self, name: &CStr) -> bool { // SAFETY: By the invariant of `CStr`, `name` is null-terminated. @@ -78,3 +104,53 @@ unsafe fn dec_ref(obj: ptr::NonNull) { unsafe { bindings::fwnode_handle_put(obj.cast().as_ptr()) } } } + +enum Node<'a> { + Borrowed(&'a FwNode), + Owned(ARef), +} + +impl core::fmt::Display for FwNode { + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result { + // The logic here is the same as the one in lib/vsprintf.c + // (fwnode_full_name_string). + + // SAFETY: `self.as_raw()` is valid by its type invariant. + let num_parents =3D unsafe { bindings::fwnode_count_parents(self.a= s_raw()) }; + + for depth in (0..=3Dnum_parents).rev() { + let fwnode =3D if depth =3D=3D 0 { + Node::Borrowed(self) + } else { + // SAFETY: `self.as_raw()` is valid. + let ptr =3D unsafe { bindings::fwnode_get_nth_parent(self.= as_raw(), depth) }; + // SAFETY: + // - The depth passed to `fwnode_get_nth_parent` is + // within the valid range, so the returned pointer is + // not null. + // - The reference count was incremented by + // `fwnode_get_nth_parent`. + // - That increment is relinquished to + // `FwNode::from_raw`. + Node::Owned(unsafe { FwNode::from_raw(ptr) }) + }; + // Take a reference to the owned or borrowed `FwNode`. + let fwnode: &FwNode =3D match &fwnode { + Node::Borrowed(f) =3D> f, + Node::Owned(f) =3D> f, + }; + + // SAFETY: `fwnode` is valid by its type invariant. + let prefix =3D unsafe { bindings::fwnode_get_name_prefix(fwnod= e.as_raw()) }; + if !prefix.is_null() { + // SAFETY: `fwnode_get_name_prefix` returns null or a + // valid C string. + let prefix =3D unsafe { CStr::from_char_ptr(prefix) }; + write!(f, "{prefix}")?; + } + write!(f, "{}", fwnode.display_name())?; + } + + Ok(()) + } +} --=20 2.49.0