From patchwork Thu Mar 20 22:27:43 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 14024600 X-Patchwork-Delegate: bhelgaas@google.com Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5FED31B422A; Thu, 20 Mar 2025 22:28:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742509713; cv=none; b=JOBtDWT0R628vxSgbmILluokzkK6ZRkqw3L/rT/Dz/2DouPSQrE5Ywa5sVY/tm6T37Fe5pQZTg4vDGlkzw2IXKc4uwGuemrKum4SoVQorqzn7cUXdfLvbJ43ht22BUrTqXZ8K6aQhAAdl/YJQPfsvVfQkDjHSUOAPEIqJtiq6/o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742509713; c=relaxed/simple; bh=HhRSRCpXSFmxEsrtP/Su72cgc0XjK9N/nmHPf0AN9A0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SyH9IszolMeXP3IFhpWjWbNbSYnrVwzsj3tTYbpP9ybz0OhP3RL+dmXyR7HarIp7E6CmFQFostNte8y+E0Ct29a7SsH4g8QKsckjsSkzZUnFw6Bb8FGvw+EeP0Zxd4VqWdpc4Kw2G1xvUNANg4NQYpYRE8OJ+aH5g7rZl5uWu0o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OVBKluKi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OVBKluKi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3417C4CEE3; Thu, 20 Mar 2025 22:28:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742509712; bh=HhRSRCpXSFmxEsrtP/Su72cgc0XjK9N/nmHPf0AN9A0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OVBKluKiT6sMtv+Gve8DS0qobblLGUkrPLSIXeU7MIR4BcU9stYxVYPX2gLFpAIqe pe7jZeMikOu6dHKl9TTeYLOngqB2nj3AkVO225liBESTI45PHdTAQt49dyKoHNNMHr ZDuS61/ov3FdkwO3PbX89Eh2lg3BsoeziMSqwOhxpSY/ylRFikkZTNEAMRgTOtkDtb m4k5dma34/V3Ll3F3N/kz+td9vu7g46YtYOlxS1xM9DqZWcmfKpmR9B/lyJvvDJBTX xY88PSgFxvv2bV5d0//2Dpy5yuAULJI5OxmgvPj9tLOLTpLHxV7qGwQscS8YOuKHYL /l4R6+qO7sJvg== From: Danilo Krummrich To: bhelgaas@google.com, gregkh@linuxfoundation.org, rafael@kernel.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu Cc: linux-pci@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH v2 1/4] rust: device: implement Device::parent() Date: Thu, 20 Mar 2025 23:27:43 +0100 Message-ID: <20250320222823.16509-2-dakr@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250320222823.16509-1-dakr@kernel.org> References: <20250320222823.16509-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Device::parent() returns a reference to the device' parent device, if any. Reviewed-by: Alice Ryhl Signed-off-by: Danilo Krummrich --- rust/kernel/device.rs | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 21b343a1dc4d..f6bdc2646028 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -65,6 +65,21 @@ pub(crate) fn as_raw(&self) -> *mut bindings::device { self.0.get() } + /// Returns a reference to the parent device, if any. + pub fn parent<'a>(&self) -> Option<&'a Self> { + // SAFETY: + // - By the type invariant `self.as_raw()` is always valid. + // - The parent device is only ever set at device creation. + let parent = unsafe { (*self.as_raw()).parent }; + + if parent.is_null() { + None + } else { + // SAFETY: Since `parent` is not NULL, it must be a valid pointer to a `struct device`. + Some(unsafe { Self::as_ref(parent) }) + } + } + /// Convert a raw C `struct device` pointer to a `&'a Device`. /// /// # Safety From patchwork Thu Mar 20 22:27:44 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 14024601 X-Patchwork-Delegate: bhelgaas@google.com Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A61F71B422A; Thu, 20 Mar 2025 22:28:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742509716; cv=none; b=YpboVLBGldkvGcbQuooza2RajZo6FQl5eUJ21KltfYEcxMaxKAdBOZIs/cZHS942eltScH4l1a7DzkaQqUk5tEdSlzly1V5gk5/DQeChfWPHINU7d2jlhiefTE2ffRVwMisH1gJ4F6wthKGwCLk3AzCqPpSehgnLnlh9uBnvZJo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742509716; c=relaxed/simple; bh=SQZafYFP1JrZU2z5rRL7rGUnXA9Ni4v/58cfQdkfXYM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gGRvz1gdN2noXuYQ8NjDIHaOR81y1x3YRXZS4O8Vv5TxdtlmvN7lzI1vzO+vWI040VcsftC8kBTD2rGCW8KykQUaSTWNClIqSuheaUXMwSaYydJLEJ/ZhaUMg92MJpOgGnu/LX8c2Ngvb6XoUlFs7MbJkY/LsvKKV6rMwPnh9+w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LSq/oMcD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LSq/oMcD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CA72C4CEDD; Thu, 20 Mar 2025 22:28:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742509716; bh=SQZafYFP1JrZU2z5rRL7rGUnXA9Ni4v/58cfQdkfXYM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LSq/oMcDW+enuh/46SbHigMnLYowagFmQYDdPVo8zfcXTE8TUMy4rax0NlGxd3hx4 4UTuey/6goNyoOYCEa3D3L2wror774GObVbo7hFlRxfQK7BVLaocRcVtfPypMPTF/S GMn62Og6Jct4tiYa3wcG+1OuftWMBwlcIpaAMuLxfVvWjhP8mJXsSFzptisIE9cnON DSNVIFvBQDfVQT2jIYpDVDAMzGyoSAqG8RsZzMHjF9ETwMr+GDjjULSNvlXap/qFam SCneUP1p7XI1K57kLjhF84agQsDBtxe55yD2MHRoMvjElh8+vaezqO2QJOcZuTO1+7 RVEncmCmwp9ww== From: Danilo Krummrich To: bhelgaas@google.com, gregkh@linuxfoundation.org, rafael@kernel.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu Cc: linux-pci@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH v2 2/4] rust: device: implement bus_type_raw() Date: Thu, 20 Mar 2025 23:27:44 +0100 Message-ID: <20250320222823.16509-3-dakr@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250320222823.16509-1-dakr@kernel.org> References: <20250320222823.16509-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement bus_type_raw(), which returns a raw pointer to the device' struct bus_type. This is useful for bus devices, to implement the following trait. impl TryFrom<&Device> for &pci::Device With this a caller can try to get the bus specific device from a generic device in a safe way. try_from() will only succeed if the generic device' bus type pointer matches the pointer of the bus' type. Reviewed-by: Alice Ryhl Signed-off-by: Danilo Krummrich Reviewed-by: Benno Lossin --- rust/kernel/device.rs | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index f6bdc2646028..1b554fdd93e9 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -80,6 +80,16 @@ pub fn parent<'a>(&self) -> Option<&'a Self> { } } + /// Returns a raw pointer to the device' bus type. + #[expect(unused)] + pub(crate) fn bus_type_raw(&self) -> *const bindings::bus_type { + // SAFETY: + // - By the type invariants, `self.as_raw()` is a valid pointer to a `struct device`. + // - `dev->bus` is a pointer to a `const struct bus_type`, which is only ever set at device + // creation. + unsafe { (*self.as_raw()).bus } + } + /// Convert a raw C `struct device` pointer to a `&'a Device`. /// /// # Safety From patchwork Thu Mar 20 22:27:45 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 14024602 X-Patchwork-Delegate: bhelgaas@google.com Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B63901B422A; Thu, 20 Mar 2025 22:28:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742509720; cv=none; b=Iet1xDAYEtTQpuWZ8igzhadzWk1kwmo8hDoy/uubC20UAZqjPS3kLKfDjwcsRtbCE5tSqM1HBcR/xKcilZbACNjHqZg+1QK+tlYzz+MByFod4BkAsjw67lIW6wc3z1ycDUfa1jg98DDY83EDBR61M5d1mLwS7B8ZFX4wdsTV3wk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742509720; c=relaxed/simple; bh=R3UfaAoWA9hqb0IAABlkpB/RL6uS8H409kUbpJ/3C60=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ho9aqfrOl6u4C3O3DliaLKjWG6t2Fj9yytmEJmBz8NKq3Djfl77ko57j0AJleKtEUQRvmlqp0cVGg4WyZmJUGQGrRm+yqAJR0hrNZkjTqrM6BmwwV/Tby42iFqsVskzdlNgES6tL1R39819q0DkYmgEAKZ/1FU93AgoPmmhOZTo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BAF5iJQT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BAF5iJQT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC935C4CEDD; Thu, 20 Mar 2025 22:28:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742509720; bh=R3UfaAoWA9hqb0IAABlkpB/RL6uS8H409kUbpJ/3C60=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BAF5iJQTPJZfYskoNEbj43YnWINaxd/u4Nhz3KSjFsfW1tLXJOTtejb0HMKgEQrHQ KdlHGUpfHTc2pNRmEKRJ7ORU7Sbv0vnUix39ChJQadfvMXNLpI4fY1S2FBLHrlZLpz rvlycKez0bexTK9u7vWvUzdY/8Bmg8LFB/cWD2zGkxw+dNYqoQSjLiXW0KuM/DWshW /zKjrRTO0bJWeQnMXVTyo71h20H00pZvYmsH/mkw3RLz7Yzl7Qc8NlLj0hWTrkgz5/ 3OzDB2XTQIhyDK05aFKcNgi+fMJ//hA2ArhL3ffxrxjA5Fqh1m2HwWFsgtXKVR4Db3 8PeXbcEUBW+aA== From: Danilo Krummrich To: bhelgaas@google.com, gregkh@linuxfoundation.org, rafael@kernel.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu Cc: linux-pci@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH v2 3/4] rust: pci: impl TryFrom<&Device> for &pci::Device Date: Thu, 20 Mar 2025 23:27:45 +0100 Message-ID: <20250320222823.16509-4-dakr@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250320222823.16509-1-dakr@kernel.org> References: <20250320222823.16509-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement TryFrom<&device::Device> for &Device. This allows us to get a &pci::Device from a generic &Device in a safe way; the conversion fails if the device' bus type does not match with the PCI bus type. Reviewed-by: Alice Ryhl Signed-off-by: Danilo Krummrich Reviewed-by: Benno Lossin --- rust/kernel/device.rs | 1 - rust/kernel/pci.rs | 21 +++++++++++++++++++-- 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 1b554fdd93e9..190719a04686 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -81,7 +81,6 @@ pub fn parent<'a>(&self) -> Option<&'a Self> { } /// Returns a raw pointer to the device' bus type. - #[expect(unused)] pub(crate) fn bus_type_raw(&self) -> *const bindings::bus_type { // SAFETY: // - By the type invariants, `self.as_raw()` is a valid pointer to a `struct device`. diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs index 22a32172b108..b717bcdb9abf 100644 --- a/rust/kernel/pci.rs +++ b/rust/kernel/pci.rs @@ -6,7 +6,7 @@ use crate::{ alloc::flags::*, - bindings, device, + bindings, container_of, device, device_id::RawDeviceId, devres::Devres, driver, @@ -20,7 +20,7 @@ use core::{ marker::PhantomData, ops::Deref, - ptr::{addr_of_mut, NonNull}, + ptr::{addr_of, addr_of_mut, NonNull}, }; use kernel::prelude::*; @@ -466,6 +466,23 @@ fn as_ref(&self) -> &device::Device { } } +impl TryFrom<&device::Device> for &Device { + type Error = kernel::error::Error; + + fn try_from(dev: &device::Device) -> Result { + if dev.bus_type_raw() != addr_of!(bindings::pci_bus_type) { + return Err(EINVAL); + } + + // SAFETY: We've just verified that the bus type of `dev` equals `bindings::pci_bus_type`, + // hence `dev` must be embedded in a valid `struct pci_dev`. + let pdev = unsafe { container_of!(dev.as_raw(), bindings::pci_dev, dev) }; + + // SAFETY: `pdev` is a valid pointer to a `struct pci_dev`. + Ok(unsafe { &*pdev.cast() }) + } +} + // SAFETY: A `Device` is always reference-counted and can be released from any thread. unsafe impl Send for Device {} From patchwork Thu Mar 20 22:27:46 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 14024603 X-Patchwork-Delegate: bhelgaas@google.com Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E82681B422A; Thu, 20 Mar 2025 22:28:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742509724; cv=none; b=r5/4TYJ0s439xNYTAX+/FVXdyjl9mY2wtXjNROu8wC4pSB0OOLyJcDWCj2q1ISYsCPRcS7yFfeMT8jAsKMV7zjO2BELqaY2JWnPu2B3JnWPNL3nCNwATjBLFG9nPgRXZi2R9Ai/RxIC6PRkxLTWlbPPqiWKzNOcRdtx2KAqApwc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742509724; c=relaxed/simple; bh=uKiDVjqXqoM1jJa6VHOyG2y9M/M3KF8/oYD/JGcLH6s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CuovsKSv+8sjSSPrf4kvCEcGrDUysK45n/okobRBU4957vJ+w9NkRuygKzuGbP7T8+wCra9+EkKHjEmVb2q0LB1ZndyQ29f2Q+0o6MV+dQikCnOTYoJs+ctnLK5FD4NHVUI6jsCRtgOVWxARAVuDnb1NroIIhu08TFvts9wSysA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O5TnhhjS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="O5TnhhjS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9852BC4CEE3; Thu, 20 Mar 2025 22:28:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742509723; bh=uKiDVjqXqoM1jJa6VHOyG2y9M/M3KF8/oYD/JGcLH6s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=O5TnhhjS8/65mAe7kflOqEpFEWsoZ/1SlwSLgDGc/CSvOpY4LJen769jEqHMdBG5A qMCEgqdbwprJwpV0MFJiJbnwyu3geHNWpZNjA+WCZEIHTkHw/SfT86shnxoCHNS24g MoCnoefJWM+Rz7aVEimnU0WOeATLiJ6iQRZIFXdn0T99dAPJXmdvQ3hKO+eAaKF68y pux/gXoIyE5CwTSsKH+kc0O6P0nqXPFpNrJWSGtfFDdFLdKIyk+oH99dR/ecFybupK f7vVaAx54q/P5odJAhwQSpCZWa6nWHt1FKFsNJvkMijtDz2YnLF1ddAgeodB9e4jw/ s5OXrRvb0D29A== From: Danilo Krummrich To: bhelgaas@google.com, gregkh@linuxfoundation.org, rafael@kernel.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu Cc: linux-pci@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH v2 4/4] rust: platform: impl TryFrom<&Device> for &platform::Device Date: Thu, 20 Mar 2025 23:27:46 +0100 Message-ID: <20250320222823.16509-5-dakr@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250320222823.16509-1-dakr@kernel.org> References: <20250320222823.16509-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement TryFrom<&device::Device> for &Device. This allows us to get a &platform::Device from a generic &Device in a safe way; the conversion fails if the device' bus type does not match with the platform bus type. Reviewed-by: Alice Ryhl Signed-off-by: Danilo Krummrich Reviewed-by: Benno Lossin --- rust/kernel/platform.rs | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs index e37531bae8e9..c17fc6e7c596 100644 --- a/rust/kernel/platform.rs +++ b/rust/kernel/platform.rs @@ -5,7 +5,7 @@ //! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h) use crate::{ - bindings, device, driver, + bindings, container_of, device, driver, error::{to_result, Result}, of, prelude::*, @@ -17,7 +17,7 @@ use core::{ marker::PhantomData, ops::Deref, - ptr::{addr_of_mut, NonNull}, + ptr::{addr_of, addr_of_mut, NonNull}, }; /// An adapter for the registration of platform drivers. @@ -234,6 +234,24 @@ fn as_ref(&self) -> &device::Device { } } +impl TryFrom<&device::Device> for &Device { + type Error = kernel::error::Error; + + fn try_from(dev: &device::Device) -> Result { + if dev.bus_type_raw() != addr_of!(bindings::platform_bus_type) { + return Err(EINVAL); + } + + // SAFETY: We've just verified that the bus type of `dev` equals + // `bindings::platform_bus_type`, hence `dev` must be embedded in a valid + // `struct platform_device`. + let pdev = unsafe { container_of!(dev.as_raw(), bindings::platform_device, dev) }; + + // SAFETY: `pdev` is a valid pointer to a `struct platform_device`. + Ok(unsafe { &*pdev.cast() }) + } +} + // SAFETY: A `Device` is always reference-counted and can be released from any thread. unsafe impl Send for Device {}