Add STM32MP25 SPI NOR support

Merge series from patrice.chotard@foss.st.com:

This series adds SPI NOR support for STM32MP25 SoCs from STMicroelectronics.

On STM32MP25 SoCs family, an Octo Memory Manager block manages the muxing,
the memory area split, the chip select override and the time constraint
between its 2 Octo SPI children.

Due to these depedencies, this series adds support for:
  - Octo Memory Manager driver (not applied for SPI).
  - Octo SPI driver.
  - yaml schema for Octo Memory Manager and Octo SPI drivers.

The device tree files adds Octo Memory Manager and its 2 associated Octo
SPI chidren in stm32mp251.dtsi and adds SPI NOR support in stm32mp257f-ev1
board.

6 files changed, 74 insertions, 4 deletions

diff --git a/rust/Makefile b/rust/Makefile
index 8fcfd60447bc..ea3849eb78f6 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -144,7 +144,7 @@ rusttestlib-kernel: private rustc_target_flags = --extern ffi \
     --extern bindings --extern uapi
 rusttestlib-kernel: $(src)/kernel/lib.rs \
     rusttestlib-bindings rusttestlib-uapi rusttestlib-build_error \
-    $(obj)/libmacros.so $(obj)/bindings.o FORCE
+    $(obj)/$(libmacros_name) $(obj)/bindings.o FORCE
 	+$(call if_changed,rustc_test_library)
 
 rusttestlib-bindings: private rustc_target_flags = --extern ffi
@@ -240,6 +240,7 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
 	-fzero-call-used-regs=% -fno-stack-clash-protection \
 	-fno-inline-functions-called-once -fsanitize=bounds-strict \
 	-fstrict-flex-arrays=% -fmin-function-alignment=% \
+	-fzero-init-padding-bits=% \
 	--param=% --param asan-%
 
 # Derived from `scripts/Makefile.clang`.
@@ -331,7 +332,7 @@ $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ;
 $(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers/helpers.c FORCE
 	$(call if_changed_dep,bindgen)
 
-rust_exports = $(NM) -p --defined-only $(1) | awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ { printf $(2),$$3 }'
+rust_exports = $(NM) -p --defined-only $(1) | awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ && $$3!~/__odr_asan/ { printf $(2),$$3 }'
 
 quiet_cmd_exports = EXPORTS $@
       cmd_exports = \
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 55354e4dec14..f46cf3bb7069 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -11,6 +11,7 @@
 #include <linux/blk_types.h>
 #include <linux/blkdev.h>
 #include <linux/cred.h>
+#include <linux/device/faux.h>
 #include <linux/errname.h>
 #include <linux/ethtool.h>
 #include <linux/file.h>
diff --git a/rust/kernel/faux.rs b/rust/kernel/faux.rs
new file mode 100644
index 000000000000..5acc0c02d451
--- /dev/null
+++ b/rust/kernel/faux.rs
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+//! Abstractions for the faux bus.
+//!
+//! This module provides bindings for working with faux devices in kernel modules.
+//!
+//! C header: [`include/linux/device/faux.h`]
+
+use crate::{bindings, device, error::code::*, prelude::*};
+use core::ptr::{addr_of_mut, null, null_mut, NonNull};
+
+/// The registration of a faux device.
+///
+/// This type represents the registration of a [`struct faux_device`]. When an instance of this type
+/// is dropped, its respective faux device will be unregistered from the system.
+///
+/// # Invariants
+///
+/// `self.0` always holds a valid pointer to an initialized and registered [`struct faux_device`].
+///
+/// [`struct faux_device`]: srctree/include/linux/device/faux.h
+#[repr(transparent)]
+pub struct Registration(NonNull<bindings::faux_device>);
+
+impl Registration {
+    /// Create and register a new faux device with the given name.
+    pub fn new(name: &CStr) -> Result<Self> {
+        // SAFETY:
+        // - `name` is copied by this function into its own storage
+        // - `faux_ops` is safe to leave NULL according to the C API
+        let dev = unsafe { bindings::faux_device_create(name.as_char_ptr(), null_mut(), null()) };
+
+        // The above function will return either a valid device, or NULL on failure
+        // INVARIANT: The device will remain registered until faux_device_destroy() is called, which
+        // happens in our Drop implementation.
+        Ok(Self(NonNull::new(dev).ok_or(ENODEV)?))
+    }
+
+    fn as_raw(&self) -> *mut bindings::faux_device {
+        self.0.as_ptr()
+    }
+}
+
+impl AsRef<device::Device> for Registration {
+    fn as_ref(&self) -> &device::Device {
+        // SAFETY: The underlying `device` in `faux_device` is guaranteed by the C API to be
+        // a valid initialized `device`.
+        unsafe { device::Device::as_ref(addr_of_mut!((*self.as_raw()).dev)) }
+    }
+}
+
+impl Drop for Registration {
+    fn drop(&mut self) {
+        // SAFETY: `self.0` is a valid registered faux_device via our type invariants.
+        unsafe { bindings::faux_device_destroy(self.as_raw()) }
+    }
+}
+
+// SAFETY: The faux device API is thread-safe as guaranteed by the device core, as long as
+// faux_device_destroy() is guaranteed to only be called once - which is guaranteed by our type not
+// having Copy/Clone.
+unsafe impl Send for Registration {}
+
+// SAFETY: The faux device API is thread-safe as guaranteed by the device core, as long as
+// faux_device_destroy() is guaranteed to only be called once - which is guaranteed by our type not
+// having Copy/Clone.
+unsafe impl Sync for Registration {}
diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs
index 3f9236c1c9d5..7fd1ea8265a5 100644
--- a/rust/kernel/init.rs
+++ b/rust/kernel/init.rs
@@ -870,7 +870,7 @@ pub unsafe trait PinInit<T: ?Sized, E = Infallible>: Sized {
     /// use kernel::{types::Opaque, init::pin_init_from_closure};
     /// #[repr(C)]
     /// struct RawFoo([u8; 16]);
-    /// extern {
+    /// extern "C" {
     ///     fn init_foo(_: *mut RawFoo);
     /// }
     ///
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 496ed32b0911..398242f92a96 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -46,6 +46,7 @@ pub mod device_id;
 pub mod devres;
 pub mod driver;
 pub mod error;
+pub mod faux;
 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)]
 pub mod firmware;
 pub mod fs;
diff --git a/rust/kernel/rbtree.rs b/rust/kernel/rbtree.rs
index ee2731dad72d..0d1e75810664 100644
--- a/rust/kernel/rbtree.rs
+++ b/rust/kernel/rbtree.rs
@@ -1149,7 +1149,7 @@ pub struct VacantEntry<'a, K, V> {
 /// # Invariants
 /// - `parent` may be null if the new node becomes the root.
 /// - `child_field_of_parent` is a valid pointer to the left-child or right-child of `parent`. If `parent` is
-///     null, it is a pointer to the root of the [`RBTree`].
+///   null, it is a pointer to the root of the [`RBTree`].
 struct RawVacantEntry<'a, K, V> {
     rbtree: *mut RBTree<K, V>,
     /// The node that will become the parent of the new node if we insert one.