linux-kernel - [RFC PATCH V2 7/8] rust: Extend OPP bindings with CPU frequency table

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Message-Id: <6e703e990bd1ce864927060c53025506568fd0b8.1717750631.git.viresh.kumar@linaro.org>
Date: Fri,  7 Jun 2024 14:42:22 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>,
	Miguel Ojeda <miguel.ojeda.sandonis@...il.com>,
	Miguel Ojeda <ojeda@...nel.org>,
	Alex Gaynor <alex.gaynor@...il.com>,
	Wedson Almeida Filho <wedsonaf@...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@...sung.com>,
	Alice Ryhl <aliceryhl@...gle.com>
Cc: Viresh Kumar <viresh.kumar@...aro.org>,
	linux-pm@...r.kernel.org,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Stephen Boyd <sboyd@...nel.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
Subject: [RFC PATCH V2 7/8] rust: Extend OPP bindings with CPU frequency table

This commit adds bindings for CPUFreq core related API.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 rust/kernel/opp.rs | 61 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 1 deletion(-)

diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs
index ebcb77b52558..4833848f79b1 100644
--- a/rust/kernel/opp.rs
+++ b/rust/kernel/opp.rs
@@ -15,7 +15,10 @@
     types::{ARef, AlwaysRefCounted, Opaque},
 };
 
-use core::{ffi::c_char, marker::PhantomData, ptr};
+#[cfg(CONFIG_CPU_FREQ)]
+use crate::cpufreq;
+
+use core::{ffi::c_char, marker::PhantomData, ops::Deref, ptr};
 
 use macros::vtable;
 
@@ -343,6 +346,56 @@ extern "C" fn config_regulators(
     }
 }
 
+/// CPU Frequency table created from OPP entries.
+#[cfg(CONFIG_CPU_FREQ)]
+pub struct FreqTable {
+    dev: ARef<Device>,
+    table: cpufreq::Table,
+}
+
+#[cfg(CONFIG_CPU_FREQ)]
+impl FreqTable {
+    /// Creates new instance of [`FreqTable`] from raw pointer.
+    fn new(table: &Table) -> Result<Self> {
+        let mut ptr: *mut bindings::cpufreq_frequency_table = ptr::null_mut();
+
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe {
+            bindings::dev_pm_opp_init_cpufreq_table(table.dev.as_raw(), &mut ptr)
+        })?;
+        Ok(Self {
+            dev: table.dev.clone(),
+            // SAFETY: The `ptr` is guaranteed by the C code to be valid.
+            table: unsafe { cpufreq::Table::from_raw(ptr) },
+        })
+    }
+
+    /// Returns reference to the underlying [`cpufreq::Table`].
+    pub fn table(&self) -> &cpufreq::Table {
+        &self.table
+    }
+}
+
+#[cfg(CONFIG_CPU_FREQ)]
+impl Deref for FreqTable {
+    type Target = cpufreq::Table;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        &self.table
+    }
+}
+
+#[cfg(CONFIG_CPU_FREQ)]
+impl Drop for FreqTable {
+    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::dev_pm_opp_free_cpufreq_table(self.dev.as_raw(), &mut self.as_ptr()) };
+    }
+}
+
 /// Operating performance point (OPP) table.
 ///
 /// # Invariants
@@ -538,6 +591,12 @@ pub fn adjust_voltage(
         })
     }
 
+    /// Create cpufreq table from OPP table.
+    #[cfg(CONFIG_CPU_FREQ)]
+    pub fn to_cpufreq_table(&mut self) -> Result<FreqTable> {
+        FreqTable::new(self)
+    }
+
     /// Sets a matching OPP based on frequency.
     pub fn set_rate(&self, freq: u64) -> Result<()> {
         // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
-- 
2.31.1.272.g89b43f80a514