linux-kernel - [PATCH V8 06/14] rust: Add bare minimal bindings for clk framework

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <c68081e18d939aefc7f6dac798df6b72e81bba4b.1738832118.git.viresh.kumar@linaro.org>
Date: Thu,  6 Feb 2025 14:58:27 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>,
	Miguel Ojeda <miguel.ojeda.sandonis@...il.com>,
	Danilo Krummrich <dakr@...hat.com>,
	Miguel Ojeda <ojeda@...nel.org>,
	Alex Gaynor <alex.gaynor@...il.com>,
	Boqun Feng <boqun.feng@...il.com>,
	Gary Guo <gary@...yguo.net>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>,
	Benno Lossin <benno.lossin@...ton.me>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	Alice Ryhl <aliceryhl@...gle.com>,
	Trevor Gross <tmgross@...ch.edu>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>
Cc: Viresh Kumar <viresh.kumar@...aro.org>,
	linux-pm@...r.kernel.org,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Nishanth Menon <nm@...com>,
	rust-for-linux@...r.kernel.org,
	Manos Pitsidianakis <manos.pitsidianakis@...aro.org>,
	Erik Schilling <erik.schilling@...aro.org>,
	Alex Bennée <alex.bennee@...aro.org>,
	Joakim Bech <joakim.bech@...aro.org>,
	Rob Herring <robh@...nel.org>,
	linux-kernel@...r.kernel.org,
	linux-clk@...r.kernel.org
Subject: [PATCH V8 06/14] rust: Add bare minimal bindings for clk framework

This adds very basic bindings for the clk framework, implements only
clk_get() and clk_put(). These are the bare minimum bindings required
for many users and are simple enough to add in the first attempt.

These will be used by Rust based cpufreq / OPP core to begin with.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 MAINTAINERS                     |  1 +
 rust/bindings/bindings_helper.h |  1 +
 rust/kernel/clk.rs              | 48 +++++++++++++++++++++++++++++++++
 rust/kernel/lib.rs              |  2 ++
 4 files changed, 52 insertions(+)
 create mode 100644 rust/kernel/clk.rs

diff --git a/MAINTAINERS b/MAINTAINERS
index ff4511914e0a..604717065476 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5780,6 +5780,7 @@ F:	include/dt-bindings/clock/
 F:	include/linux/clk-pr*
 F:	include/linux/clk/
 F:	include/linux/of_clk.h
+F:	rust/kernel/clk.rs
 X:	drivers/clk/clkdev.c
 
 COMMON INTERNET FILE SYSTEM CLIENT (CIFS and SMB3)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 59b4bc49d039..4eadcf645df0 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -10,6 +10,7 @@
 #include <linux/blk-mq.h>
 #include <linux/blk_types.h>
 #include <linux/blkdev.h>
+#include <linux/clk.h>
 #include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/cred.h>
diff --git a/rust/kernel/clk.rs b/rust/kernel/clk.rs
new file mode 100644
index 000000000000..123cdb43b115
--- /dev/null
+++ b/rust/kernel/clk.rs
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Clock abstractions.
+//!
+//! C header: [`include/linux/clk.h`](srctree/include/linux/clk.h)
+
+use crate::{
+    bindings,
+    device::Device,
+    error::{from_err_ptr, Result},
+    prelude::*,
+};
+
+use core::ptr;
+
+/// A simple implementation of `struct clk` from the C code.
+#[repr(transparent)]
+pub struct Clk(*mut bindings::clk);
+
+impl Clk {
+    /// Creates `Clk` instance for a device and a connection id.
+    pub fn new(dev: &Device, name: Option<&CStr>) -> Result<Self> {
+        let con_id = if let Some(name) = name {
+            name.as_ptr() as *const _
+        } else {
+            ptr::null()
+        };
+
+        // SAFETY: It is safe to call `clk_get()`, on a device pointer earlier received from the C
+        // code.
+        Ok(Self(from_err_ptr(unsafe {
+            bindings::clk_get(dev.as_raw(), con_id)
+        })?))
+    }
+
+    /// Obtain the raw `struct clk *`.
+    pub fn as_raw(&self) -> *mut bindings::clk {
+        self.0
+    }
+}
+
+impl Drop for Clk {
+    fn drop(&mut self) {
+        // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to
+        // relinquish it now.
+        unsafe { bindings::clk_put(self.0) };
+    }
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index ccbf7fa087a0..77d3b1f82154 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -40,6 +40,8 @@
 pub mod block;
 #[doc(hidden)]
 pub mod build_assert;
+#[cfg(CONFIG_COMMON_CLK)]
+pub mod clk;
 pub mod cpu;
 pub mod cpumask;
 pub mod cred;
-- 
2.31.1.272.g89b43f80a514