netdev - [PATCH net-next v1 1/2] rust: add delay abstraction

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Message-ID: <20241001112512.4861-2-fujita.tomonori@gmail.com>
Date: Tue,  1 Oct 2024 11:25:11 +0000
From: FUJITA Tomonori <fujita.tomonori@...il.com>
To: netdev@...r.kernel.org
Cc: rust-for-linux@...r.kernel.org,
	andrew@...n.ch,
	hkallweit1@...il.com,
	tmgross@...ch.edu,
	ojeda@...nel.org,
	alex.gaynor@...il.com,
	gary@...yguo.net,
	bjorn3_gh@...tonmail.com,
	benno.lossin@...ton.me,
	a.hindborg@...sung.com,
	aliceryhl@...gle.com
Subject: [PATCH net-next v1 1/2] rust: add delay abstraction

Add an abstraction for sleep functions in `include/linux/delay.h` for
dealing with hardware delays.

The kernel supports several `sleep` functions for handles various
lengths of delay. This adds fsleep helper function, internally calls
an appropriate sleep function.

This is used by QT2025 PHY driver to wait until a PHY becomes ready.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@...il.com>
---
 rust/bindings/bindings_helper.h |  1 +
 rust/helpers/delay.c            |  8 ++++++++
 rust/helpers/helpers.c          |  1 +
 rust/kernel/delay.rs            | 18 ++++++++++++++++++
 rust/kernel/lib.rs              |  1 +
 5 files changed, 29 insertions(+)
 create mode 100644 rust/helpers/delay.c
 create mode 100644 rust/kernel/delay.rs

diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index ae82e9c941af..29a2f59294ba 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/delay.h>
 #include <linux/errname.h>
 #include <linux/ethtool.h>
 #include <linux/firmware.h>
diff --git a/rust/helpers/delay.c b/rust/helpers/delay.c
new file mode 100644
index 000000000000..7ae64ad8141d
--- /dev/null
+++ b/rust/helpers/delay.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/delay.h>
+
+void rust_helper_fsleep(unsigned long usecs)
+{
+	fsleep(usecs);
+}
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 30f40149f3a9..279ea662ee3b 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -12,6 +12,7 @@
 #include "build_assert.c"
 #include "build_bug.c"
 #include "err.c"
+#include "delay.c"
 #include "kunit.c"
 #include "mutex.c"
 #include "page.c"
diff --git a/rust/kernel/delay.rs b/rust/kernel/delay.rs
new file mode 100644
index 000000000000..79f51a9608b5
--- /dev/null
+++ b/rust/kernel/delay.rs
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Delay and sleep routines.
+//!
+//! C headers: [`include/linux/delay.h`](srctree/include/linux/delay.h).
+
+use core::{ffi::c_ulong, time::Duration};
+
+/// Sleeps for a given duration.
+///
+/// Equivalent to the kernel's [`fsleep`] function, internally calls `udelay`,
+/// `usleep_range`, or `msleep`.
+///
+/// This function can only be used in a nonatomic context.
+pub fn sleep(duration: Duration) {
+    // SAFETY: FFI call.
+    unsafe { bindings::fsleep(duration.as_micros() as c_ulong) }
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 22a3bfa5a9e9..c08cb5509c82 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -30,6 +30,7 @@
 #[cfg(CONFIG_BLOCK)]
 pub mod block;
 mod build_assert;
+pub mod delay;
 pub mod device;
 pub mod error;
 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)]
-- 
2.34.1