spi: aspeed: Improve handling of shared SPI

Merge series from Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>:

This patch series improves handling of SPI controllers that are
shared by spi-mem devices and other SPI peripherals.

The primary goal of this series is to support non-spi-mem devices in
the ASPEED FMC/SPI controller driver. It also addresses an issue in
the spi-mem framework observed when different types of SPI devices
operate concurrently on the same controller, ensuring that spi-mem
operations are properly serialized.

1 files changed, 18 insertions, 9 deletions

diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 82e128431f08..bea76ca9c3da 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -50,13 +50,22 @@ pub use self::irq::{
 /// An adapter for the registration of PCI drivers.
 pub struct Adapter<T: Driver>(T);
 
-// SAFETY: A call to `unregister` for a given instance of `RegType` is guaranteed to be valid if
+// SAFETY:
+// - `bindings::pci_driver` is a C type declared as `repr(C)`.
+// - `T` is the type of the driver's device private data.
+// - `struct pci_driver` embeds a `struct device_driver`.
+// - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`.
+unsafe impl<T: Driver + 'static> driver::DriverLayout for Adapter<T> {
+    type DriverType = bindings::pci_driver;
+    type DriverData = T;
+    const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver);
+}
+
+// SAFETY: A call to `unregister` for a given instance of `DriverType` 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::pci_driver;
-
     unsafe fn register(
-        pdrv: &Opaque<Self::RegType>,
+        pdrv: &Opaque<Self::DriverType>,
         name: &'static CStr,
         module: &'static ThisModule,
     ) -> Result {
@@ -68,14 +77,14 @@ unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
             (*pdrv.get()).id_table = T::ID_TABLE.as_ptr();
         }
 
-        // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.
+        // SAFETY: `pdrv` is guaranteed to be a valid `DriverType`.
         to_result(unsafe {
             bindings::__pci_register_driver(pdrv.get(), module.0, name.as_char_ptr())
         })
     }
 
-    unsafe fn unregister(pdrv: &Opaque<Self::RegType>) {
-        // SAFETY: `pdrv` is guaranteed to be a valid `RegType`.
+    unsafe fn unregister(pdrv: &Opaque<Self::DriverType>) {
+        // SAFETY: `pdrv` is guaranteed to be a valid `DriverType`.
         unsafe { bindings::pci_unregister_driver(pdrv.get()) }
     }
 }
@@ -114,9 +123,9 @@ impl<T: Driver + 'static> Adapter<T> {
         // SAFETY: `remove_callback` is only ever called after a successful call to
         // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
         // and stored a `Pin<KBox<T>>`.
-        let data = unsafe { pdev.as_ref().drvdata_obtain::<T>() };
+        let data = unsafe { pdev.as_ref().drvdata_borrow::<T>() };
 
-        T::unbind(pdev, data.as_ref());
+        T::unbind(pdev, data);
     }
 }