Merge tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core and debugfs updates from Greg KH:
 "Here is the big set of driver core and debugfs updates for 6.14-rc1.

  Included in here is a bunch of driver core, PCI, OF, and platform rust
  bindings (all acked by the different subsystem maintainers), hence the
  merge conflict with the rust tree, and some driver core api updates to
  mark things as const, which will also require some fixups due to new
  stuff coming in through other trees in this merge window.

  There are also a bunch of debugfs updates from Al, and there is at
  least one user that does have a regression with these, but Al is
  working on tracking down the fix for it. In my use (and everyone
  else's linux-next use), it does not seem like a big issue at the
  moment.

  Here's a short list of the things in here:

   - driver core rust bindings for PCI, platform, OF, and some i/o
     functions.

     We are almost at the "write a real driver in rust" stage now,
     depending on what you want to do.

   - misc device rust bindings and a sample driver to show how to use
     them

   - debugfs cleanups in the fs as well as the users of the fs api for
     places where drivers got it wrong or were unnecessarily doing
     things in complex ways.

   - driver core const work, making more of the api take const * for
     different parameters to make the rust bindings easier overall.

   - other small fixes and updates

  All of these have been in linux-next with all of the aforementioned
  merge conflicts, and the one debugfs issue, which looks to be resolved
  "soon""

* tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits)
  rust: device: Use as_char_ptr() to avoid explicit cast
  rust: device: Replace CString with CStr in property_present()
  devcoredump: Constify 'struct bin_attribute'
  devcoredump: Define 'struct bin_attribute' through macro
  rust: device: Add property_present()
  saner replacement for debugfs_rename()
  orangefs-debugfs: don't mess with ->d_name
  octeontx2: don't mess with ->d_parent or ->d_parent->d_name
  arm_scmi: don't mess with ->d_parent->d_name
  slub: don't mess with ->d_name
  sof-client-ipc-flood-test: don't mess with ->d_name
  qat: don't mess with ->d_name
  xhci: don't mess with ->d_iname
  mtu3: don't mess wiht ->d_iname
  greybus/camera - stop messing with ->d_iname
  mediatek: stop messing with ->d_iname
  netdevsim: don't embed file_operations into your structs
  b43legacy: make use of debugfs_get_aux()
  b43: stop embedding struct file_operations into their objects
  carl9170: stop embedding file_operations into their objects
  ...

1 files changed, 200 insertions, 0 deletions

diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
new file mode 100644
index 0000000000000..50e6b04218132
--- /dev/null
+++ b/rust/kernel/platform.rs
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Abstractions for the platform bus.
+//!
+//! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h)
+
+use crate::{
+    bindings, container_of, device, driver,
+    error::{to_result, Result},
+    of,
+    prelude::*,
+    str::CStr,
+    types::{ARef, ForeignOwnable, Opaque},
+    ThisModule,
+};
+
+use core::ptr::addr_of_mut;
+
+/// An adapter for the registration of platform drivers.
+pub struct Adapter<T: Driver>(T);
+
+// SAFETY: A call to `unregister` for a given instance of `RegType` is guaranteed to be valid if
+// a preceding call to `register` has been successful.
+unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
+    type RegType = bindings::platform_driver;
+
+    unsafe fn register(
+        pdrv: &Opaque<Self::RegType>,
+        name: &'static CStr,
+        module: &'static ThisModule,
+    ) -> Result {
+        let of_table = match T::OF_ID_TABLE {
+            Some(table) => table.as_ptr(),
+            None => core::ptr::null(),
+        };
+
+        // SAFETY: It's safe to set the fields of `struct platform_driver` on initialization.
+        unsafe {
+            (*pdrv.get()).driver.name = name.as_char_ptr();
+            (*pdrv.get()).probe = Some(Self::probe_callback);
+            (*pdrv.get()).remove = Some(Self::remove_callback);
+            (*pdrv.get()).driver.of_match_table = of_table;
+        }
+
+        // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.
+        to_result(unsafe { bindings::__platform_driver_register(pdrv.get(), module.0) })
+    }
+
+    unsafe fn unregister(pdrv: &Opaque<Self::RegType>) {
+        // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.
+        unsafe { bindings::platform_driver_unregister(pdrv.get()) };
+    }
+}
+
+impl<T: Driver + 'static> Adapter<T> {
+    extern "C" fn probe_callback(pdev: *mut bindings::platform_device) -> kernel::ffi::c_int {
+        // SAFETY: The platform bus only ever calls the probe callback with a valid `pdev`.
+        let dev = unsafe { device::Device::get_device(addr_of_mut!((*pdev).dev)) };
+        // SAFETY: `dev` is guaranteed to be embedded in a valid `struct platform_device` by the
+        // call above.
+        let mut pdev = unsafe { Device::from_dev(dev) };
+
+        let info = <Self as driver::Adapter>::id_info(pdev.as_ref());
+        match T::probe(&mut pdev, info) {
+            Ok(data) => {
+                // Let the `struct platform_device` own a reference of the driver's private data.
+                // SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a
+                // `struct platform_device`.
+                unsafe { bindings::platform_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::platform_device) {
+        // SAFETY: `pdev` is a valid pointer to a `struct platform_device`.
+        let ptr = unsafe { bindings::platform_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<T>` pointer created through `KBox::into_foreign`.
+        let _ = unsafe { KBox::<T>::from_foreign(ptr) };
+    }
+}
+
+impl<T: Driver + 'static> driver::Adapter for Adapter<T> {
+    type IdInfo = T::IdInfo;
+
+    fn of_id_table() -> Option<of::IdTable<Self::IdInfo>> {
+        T::OF_ID_TABLE
+    }
+}
+
+/// Declares a kernel module that exposes a single platform driver.
+///
+/// # Examples
+///
+/// ```ignore
+/// kernel::module_platform_driver! {
+///     type: MyDriver,
+///     name: "Module name",
+///     author: "Author name",
+///     description: "Description",
+///     license: "GPL v2",
+/// }
+/// ```
+#[macro_export]
+macro_rules! module_platform_driver {
+    ($($f:tt)*) => {
+        $crate::module_driver!(<T>, $crate::platform::Adapter<T>, { $($f)* });
+    };
+}
+
+/// The platform driver trait.
+///
+/// Drivers must implement this trait in order to get a platform driver registered.
+///
+/// # Example
+///
+///```
+/// # use kernel::{bindings, c_str, of, platform};
+///
+/// struct MyDriver;
+///
+/// kernel::of_device_table!(
+///     OF_TABLE,
+///     MODULE_OF_TABLE,
+///     <MyDriver as platform::Driver>::IdInfo,
+///     [
+///         (of::DeviceId::new(c_str!("test,device")), ())
+///     ]
+/// );
+///
+/// impl platform::Driver for MyDriver {
+///     type IdInfo = ();
+///     const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+///
+///     fn probe(
+///         _pdev: &mut platform::Device,
+///         _id_info: Option<&Self::IdInfo>,
+///     ) -> Result<Pin<KBox<Self>>> {
+///         Err(ENODEV)
+///     }
+/// }
+///```
+pub trait Driver {
+    /// The type holding driver private data about each device id supported by the driver.
+    ///
+    /// TODO: Use associated_type_defaults once stabilized:
+    ///
+    /// type IdInfo: 'static = ();
+    type IdInfo: 'static;
+
+    /// The table of OF device ids supported by the driver.
+    const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>>;
+
+    /// Platform 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_info: Option<&Self::IdInfo>) -> Result<Pin<KBox<Self>>>;
+}
+
+/// The platform device representation.
+///
+/// A platform device is based on an always reference counted `device:Device` instance. Cloning a
+/// platform device, hence, also increments the base device' reference count.
+///
+/// # Invariants
+///
+/// `Device` holds a valid reference of `ARef<device::Device>` whose underlying `struct device` is a
+/// member of a `struct platform_device`.
+#[derive(Clone)]
+pub struct Device(ARef<device::Device>);
+
+impl Device {
+    /// Convert a raw kernel device into a `Device`
+    ///
+    /// # Safety
+    ///
+    /// `dev` must be an `Aref<device::Device>` whose underlying `bindings::device` is a member of a
+    /// `bindings::platform_device`.
+    unsafe fn from_dev(dev: ARef<device::Device>) -> Self {
+        Self(dev)
+    }
+
+    fn as_raw(&self) -> *mut bindings::platform_device {
+        // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device`
+        // embedded in `struct platform_device`.
+        unsafe { container_of!(self.0.as_raw(), bindings::platform_device, dev) }.cast_mut()
+    }
+}
+
+impl AsRef<device::Device> for Device {
+    fn as_ref(&self) -> &device::Device {
+        &self.0
+    }
+}