From patchwork Tue Oct 22 21:31:48 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13846179 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 87C6E1CEAA7; Tue, 22 Oct 2024 21:33:33 +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=1729632813; cv=none; b=KjQvzdzLWDhOjCbMRERswE2qOtTmtq/SSybcqZRzcLPNkQvUgTfKhqSOpaUlaOWlCtgRL/iISxwrtMnHqM12ylvRouTwBtt2m6+f1I0uPZeMG/otrFhh6bZf+p9yVAnuqQSYdtEMuPQb3RXqFXWZcAnVWtVF6xcQg3orIEO0oAk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729632813; c=relaxed/simple; bh=f1g2lGypUnMSWSiEHr5MqHApk0asEuig3kZAXhnIuWM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bdoAsdGfhVZ1zPWrIe5rRvv0n8WAJNjM/HNVqPv/t9YODvrYxcR1L8zNYRktfqr5c4VciJvL7SOAFg0fer9mIDQb4VRx4IeWG4Le2uQE9TvgY4TYDLcjPsmGf9W3uMuGXDNfZFlIHas3X8VdeEzdQsW2pskmhJaAqj4iRncCgi0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cVOouSNX; 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="cVOouSNX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F7EDC4CEC7; Tue, 22 Oct 2024 21:33:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729632813; bh=f1g2lGypUnMSWSiEHr5MqHApk0asEuig3kZAXhnIuWM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cVOouSNXzvADmoyI/wvdj2wDtmokqY5U9leZT76/y3i5e24o3NkpM03wnbiQHpoMx KA576ZT7L1OQvom3SGBlgHojy1Ci0lpuTSL/pupWKPskmLOwOtQ7Nhah4YG0+T6kkE zIzIPrXAquwkOHPrGwvg5/bA2SW4V61DBCYyjBrNjMtLORONQwwQrly50yKm73mUUt DjlsRvJBeUBw7rb6RCQNdznmWE/OcUhd3LYlXFnFQpdg0S8SXrKnGdeY02ForiKcqW 1GfAugh3JZU84cp+nA/t8BghiU7VYYQd9fhJ5C08e7Pv+Cy9mL1nPBRBKGNO7Z50yL c6vhOKvIvAjsw== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v3 11/16] rust: pci: add basic PCI device / driver abstractions Date: Tue, 22 Oct 2024 23:31:48 +0200 Message-ID: <20241022213221.2383-12-dakr@kernel.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241022213221.2383-1-dakr@kernel.org> References: <20241022213221.2383-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement the basic PCI abstractions required to write a basic PCI driver. This includes the following data structures: The `pci::Driver` trait represents the interface to the driver and provides `pci::Driver::probe` for the driver to implement. The `pci::Device` abstraction represents a `struct pci_dev` and provides abstractions for common functions, such as `pci::Device::set_master`. In order to provide the PCI specific parts to a generic `driver::Registration` the `driver::RegistrationOps` trait is implemented by `pci::Adapter`. `pci::DeviceId` implements PCI device IDs based on the generic `device_id::RawDevceId` abstraction. Co-developed-by: FUJITA Tomonori Signed-off-by: FUJITA Tomonori Signed-off-by: Danilo Krummrich --- MAINTAINERS | 1 + rust/bindings/bindings_helper.h | 1 + rust/helpers/helpers.c | 1 + rust/helpers/pci.c | 18 ++ rust/kernel/lib.rs | 2 + rust/kernel/pci.rs | 284 ++++++++++++++++++++++++++++++++ 6 files changed, 307 insertions(+) create mode 100644 rust/helpers/pci.c create mode 100644 rust/kernel/pci.rs diff --git a/MAINTAINERS b/MAINTAINERS index 97914d0752fb..2d00d3845b4a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17939,6 +17939,7 @@ F: include/asm-generic/pci* F: include/linux/of_pci.h F: include/linux/pci* F: include/uapi/linux/pci* +F: rust/kernel/pci.rs PCIE DRIVER FOR AMAZON ANNAPURNA LABS M: Jonathan Chocron diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index a80783fcbe04..cd4edd6496ae 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 3acb2b9e52ec..8bc6e9735589 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -17,6 +17,7 @@ #include "kunit.c" #include "mutex.c" #include "page.c" +#include "pci.c" #include "rbtree.c" #include "rcu.c" #include "refcount.c" diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c new file mode 100644 index 000000000000..7c4f3ba49486 --- /dev/null +++ b/rust/helpers/pci.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void rust_helper_pci_set_drvdata(struct pci_dev *pdev, void *data) +{ + pci_set_drvdata(pdev, data); +} + +void *rust_helper_pci_get_drvdata(struct pci_dev *pdev) +{ + return pci_get_drvdata(pdev); +} + +u64 rust_helper_pci_resource_len(struct pci_dev *pdev, int bar) +{ + return pci_resource_len(pdev, bar); +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 5cb892419453..3ec690eb6d43 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -73,6 +73,8 @@ pub use bindings; pub mod io; pub use macros; +#[cfg(all(CONFIG_PCI, CONFIG_PCI_MSI))] +pub mod pci; pub use uapi; #[doc(hidden)] diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs new file mode 100644 index 000000000000..ccc9a5f322e4 --- /dev/null +++ b/rust/kernel/pci.rs @@ -0,0 +1,284 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Abstractions for the PCI bus. +//! +//! C header: [`include/linux/pci.h`](srctree/include/linux/pci.h) + +use crate::{ + bindings, container_of, device, + device_id::RawDeviceId, + driver, + error::{to_result, Result}, + str::CStr, + types::{ARef, ForeignOwnable}, + ThisModule, +}; +use core::ops::Deref; +use kernel::prelude::*; + +/// An adapter for the registration of PCI drivers. +pub struct Adapter(T); + +impl driver::RegistrationOps for Adapter { + type RegType = bindings::pci_driver; + + fn register( + pdrv: &mut Self::RegType, + name: &'static CStr, + module: &'static ThisModule, + ) -> Result { + pdrv.name = name.as_char_ptr(); + pdrv.probe = Some(Self::probe_callback); + pdrv.remove = Some(Self::remove_callback); + pdrv.id_table = T::ID_TABLE.as_ptr(); + + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. + to_result(unsafe { + bindings::__pci_register_driver(pdrv as _, module.0, name.as_char_ptr()) + }) + } + + fn unregister(pdrv: &mut Self::RegType) { + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. + unsafe { bindings::pci_unregister_driver(pdrv) } + } +} + +impl Adapter { + extern "C" fn probe_callback( + pdev: *mut bindings::pci_dev, + id: *const bindings::pci_device_id, + ) -> core::ffi::c_int { + // SAFETY: The PCI bus only ever calls the probe callback with a valid pointer to a + // `struct pci_dev`. + let dev = unsafe { device::Device::from_raw(&mut (*pdev).dev) }; + // SAFETY: `dev` is guaranteed to be embedded in a valid `struct pci_dev` by the call + // above. + let mut pdev = unsafe { Device::from_dev(dev) }; + + // SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct pci_device_id` and + // does not add additional invariants, so it's safe to transmute. + let id = unsafe { &*id.cast::() }; + let info = T::ID_TABLE.info(id.index()); + + match T::probe(&mut pdev, id, info) { + Ok(data) => { + // Let the `struct pci_dev` own a reference of the driver's private data. + // SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a + // `struct pci_dev`. + unsafe { bindings::pci_set_drvdata(pdev.as_raw(), data.into_foreign() as _) }; + } + Err(err) => return Error::to_errno(err), + } + + 0 + } + + extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) { + // SAFETY: The PCI bus only ever calls the remove callback with a valid pointer to a + // `struct pci_dev`. + let ptr = unsafe { bindings::pci_get_drvdata(pdev) }; + + // SAFETY: `remove_callback` is only ever called after a successful call to + // `probe_callback`, hence it's guaranteed that `ptr` points to a valid and initialized + // `KBox` pointer created through `KBox::into_foreign`. + let _ = unsafe { KBox::::from_foreign(ptr) }; + } +} + +/// Declares a kernel module that exposes a single PCI driver. +/// +/// # Example +/// +///```ignore +/// kernel::module_pci_driver! { +/// type: MyDriver, +/// name: "Module name", +/// author: "Author name", +/// description: "Description", +/// license: "GPL v2", +/// } +///``` +#[macro_export] +macro_rules! module_pci_driver { +($($f:tt)*) => { + $crate::module_driver!(, $crate::pci::Adapter, { $($f)* }); +}; +} + +/// Abstraction for bindings::pci_device_id. +#[repr(transparent)] +#[derive(Clone, Copy)] +pub struct DeviceId(bindings::pci_device_id); + +impl DeviceId { + const PCI_ANY_ID: u32 = !0; + + /// PCI_DEVICE macro. + pub const fn new(vendor: u32, device: u32) -> Self { + Self(bindings::pci_device_id { + vendor, + device, + subvendor: DeviceId::PCI_ANY_ID, + subdevice: DeviceId::PCI_ANY_ID, + class: 0, + class_mask: 0, + driver_data: 0, + override_only: 0, + }) + } + + /// PCI_DEVICE_CLASS macro. + pub const fn with_class(class: u32, class_mask: u32) -> Self { + Self(bindings::pci_device_id { + vendor: DeviceId::PCI_ANY_ID, + device: DeviceId::PCI_ANY_ID, + subvendor: DeviceId::PCI_ANY_ID, + subdevice: DeviceId::PCI_ANY_ID, + class, + class_mask, + driver_data: 0, + override_only: 0, + }) + } +} + +// Allow drivers R/O access to the fields of `pci_device_id`; should we prefer accessor functions +// to void exposing C structure fields? +impl Deref for DeviceId { + type Target = bindings::pci_device_id; + + fn deref(&self) -> &Self::Target { + &self.0 + } +} + +// SAFETY: +// * `DeviceId` is a `#[repr(transparent)` wrapper of `pci_device_id` and does not add +// additional invariants, so it's safe to transmute to `RawType`. +// * `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +unsafe impl RawDeviceId for DeviceId { + type RawType = bindings::pci_device_id; + + const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::pci_device_id, driver_data); + + fn index(&self) -> usize { + self.driver_data as _ + } +} + +/// IdTable type for PCI +pub type IdTable = &'static dyn kernel::device_id::IdTable; + +/// Create a PCI `IdTable` with its alias for modpost. +#[macro_export] +macro_rules! pci_device_table { + ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => { + const $table_name: $crate::device_id::IdArray< + $crate::pci::DeviceId, + $id_info_type, + { $table_data.len() }, + > = $crate::device_id::IdArray::new($table_data); + + $crate::module_device_table!("pci", $module_table_name, $table_name); + }; +} + +/// The PCI driver trait. +/// +/// # Example +/// +///``` +/// # use kernel::{bindings, pci}; +/// +/// struct MyDriver; +/// +/// kernel::pci_device_table!( +/// PCI_TABLE, +/// MODULE_PCI_TABLE, +/// ::IdInfo, +/// [ +/// (pci::DeviceId::new(bindings::PCI_VENDOR_ID_REDHAT, bindings::PCI_ANY_ID as u32), ()) +/// ] +/// ); +/// +/// impl pci::Driver for MyDriver { +/// type IdInfo = (); +/// const ID_TABLE: pci::IdTable = &PCI_TABLE; +/// +/// fn probe( +/// _pdev: &mut pci::Device, +/// _id: &pci::DeviceId, +/// _id_info: &Self::IdInfo, +/// ) -> Result>> { +/// Err(ENODEV) +/// } +/// } +///``` +/// Drivers must implement this trait in order to get a PCI driver registered. Please refer to the +/// `Adapter` documentation for an example. +pub trait Driver { + /// The type holding information about each device id supported by the driver. + /// + /// TODO: Use associated_type_defaults once stabilized: + /// + /// type IdInfo: 'static = (); + type IdInfo: 'static; + + /// The table of device ids supported by the driver. + const ID_TABLE: IdTable; + + /// PCI driver probe. + /// + /// Called when a new platform device is added or discovered. + /// Implementers should attempt to initialize the device here. + fn probe(dev: &mut Device, id: &DeviceId, id_info: &Self::IdInfo) -> Result>>; +} + +/// The PCI device representation. +/// +/// A PCI device is based on an always reference counted `device:Device` instance. Cloning a PCI +/// device, hence, also increments the base device' reference count. +#[derive(Clone)] +pub struct Device(ARef); + +impl Device { + /// Create a PCI Device instance from an existing `device::Device`. + /// + /// # Safety + /// + /// `dev` must be an `ARef` whose underlying `bindings::device` is a member of + /// a `bindings::pci_dev`. + pub unsafe fn from_dev(dev: ARef) -> Self { + Self(dev) + } + + fn as_raw(&self) -> *mut bindings::pci_dev { + // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device` + // embedded in `struct pci_dev`. + unsafe { container_of!(self.0.as_raw(), bindings::pci_dev, dev) as _ } + } + + /// Enable memory resources for this device. + pub fn enable_device_mem(&self) -> Result { + // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. + let ret = unsafe { bindings::pci_enable_device_mem(self.as_raw()) }; + if ret != 0 { + Err(Error::from_errno(ret)) + } else { + Ok(()) + } + } + + /// Enable bus-mastering for this device. + pub fn set_master(&self) { + // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. + unsafe { bindings::pci_set_master(self.as_raw()) }; + } +} + +impl AsRef for Device { + fn as_ref(&self) -> &device::Device { + &self.0 + } +}